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GEOCHEMISTRY ARTICLES – June 2018?Analytical ChemistryBerthod, A., Ruiz-?ngel, M.J., Carda-Broch, S., 2018. Recent advances on ionic liquid uses in separation techniques. Journal of Chromatography A 1559, 2-16.Chim, L.K., Yen, J.-Y., Huang, S.-Y., Liou, Y.-S., Tsai, L.L.-Y., 2018. Using Raman spectroscopy of carbonaceous materials to track exhumation of an active orogenic belt: An example from eastern Taiwan. Journal of Asian Earth Sciences 164, 248-259.Cunha, S.C., Fernandes, J.O., 2018. Extraction techniques with deep eutectic solvents. TrAC Trends in Analytical Chemistry 105, 225-239.Gras, R., Luong, J., Pursch, M., Shellie, R.A., 2018. Positive temperature coefficient compensating heating for analytical devices. Analytical Chemistry 90, 6426-6430.Gutiérrez Sama, S., Barrère-Mangote, C., Bouyssière, B., Giusti, P., Lobinski, R., 2018. Recent trends in element speciation analysis of crude oils and heavy petroleum fractions. TrAC Trends in Analytical Chemistry 104, 69-76.Hashemi, B., Zohrabi, P., Shamsipur, M., 2018. Recent developments and applications of different sorbents for SPE and SPME from biological samples. Talanta 187, 337-347.Lobo, L., Pereiro, R., Fernández, B., 2018. Opportunities and challenges of isotopic analysis by laser ablation ICP-MS in biological studies. TrAC Trends in Analytical Chemistry 105, 380-390.Maaten, B., Pikkor, H., Konist, A., Siirde, A., 2018. Determination of the total sulphur content of oil shale by using different analytical methods. Oil Shale 35, 144–153.Nakamura, H., 2018. Current status of water environment and their microbial biosensor techniques – Part I: Current data of water environment and recent studies on water quality investigations in Japan, and new possibility of microbial biosensor techniques. Analytical and Bioanalytical Chemistry 410, 3953-3965.Nakamura, H., 2018. Current status of water environment and their microbial biosensor techniques – Part II: Recent trends in microbial biosensor development. Analytical and Bioanalytical Chemistry 410, 3967-3989.Pasquini, C., 2018. Near infrared spectroscopy: A mature analytical technique with new perspectives – A review. Analytica Chimica Acta 1026, 8-36.Rakhmatullin, I.Z., Efimov, S.V., Tyurin, V.A., Al-Muntaser, A.A., Klimovitskii, A.E., Varfolomeev, M.A., Klochkov, V.V., 2018. Application of high resolution NMR (1H and 13C) and FTIR spectroscopy for characterization of light and heavy crude oils. Journal of Petroleum Science and Engineering 168, 256-262.Shukla, S.K., Pandey, S., Pandey, S., 2018. Applications of ionic liquids in biphasic separation: Aqueous biphasic systems and liquid–liquid equilibria. Journal of Chromatography A 1559, 44-61.Szymańska, E., 2018. Modern data science for analytical chemical data – A comprehensive review. Analytica Chimica Acta 1028, 1-10.Gas Chromatography/GC×GC/GC-MSAlinoori, A.H., Masoum, S., 2018. Multicapillary gas chromatography—temperature modulated metal oxide semiconductor sensors array detector for monitoring of volatile organic compounds in closed atmosphere using Gaussian apodization factor analysis. Analytical Chemistry 90, 6635-6642.Gras, R., Luong, J., Haddad, P.R., Shellie, R.A., 2018. Gas chromatography with simultaneous detection: Ultraviolet spectroscopy, flame ionization, and mass spectrometry. Journal of Chromatography A 1563, 171-179.Gruber, B., Weggler, B.A., Jaramillo, R., Murrell, K.A., Piotrowski, P.K., Dorman, F.L., 2018. Comprehensive two-dimensional gas chromatography in forensic science: A critical review of recent trends. TrAC Trends in Analytical Chemistry 105, 292-301.He, L., Prodhan, M.A.I., Yuan, F., Yin, X., Lorkiewicz, P.K., Wei, X., Feng, W., McClain, C., Zhang, X., 2018. Simultaneous quantification of straight-chain and branched-chain short chain fatty acids by gas chromatography mass spectrometry. Journal of Chromatography B 1092, 359-367.Kalambet, Y., Kozmin, Y., Samokhin, A., 2018. Comparison of integration rules in the case of very narrow chromatographic peaks. Chemometrics and Intelligent Laboratory Systems 179, 22-30.Kumar, K., 2018. Introducing an integral optimised warping (IOW) approach for achieving swift alignment of drifted chromatographic peaks: an optimisation of the correlation optimised warping (COW) technique. Analytical Methods 10, 2764-2774.Nan, H., Anderson, J.L., 2018. Ionic liquid stationary phases for multidimensional gas chromatography. TrAC Trends in Analytical Chemistry 105, 367-379.Pollo, B.J., Alexandrino, G.L., Augusto, F., Hantao, L.W., 2018. The impact of comprehensive two-dimensional gas chromatography on oil & gas analysis: Recent advances and applications in petroleum industry. TrAC Trends in Analytical Chemistry 105, 202-217.Primaz, C.T., Schena, T., Lazzari, E., Caram?o, E.B., Jacques, R.A., 2018. Influence of the temperature in the yield and composition of the bio-oil from the pyrolysis of spent coffee grounds: Characterization by comprehensive two dimensional gas chromatography. Fuel 232, 572-580.Purcaro, G., Stefanuto, P.-H., Franchina, F.A., Beccaria, M., Wieland-Alter, W.F., Wright, P.F., Hill, J.E., 2018. SPME-GC×GC-TOF MS fingerprint of virally-infected cell culture: Sample preparation optimization and data processing evaluation. Analytica Chimica Acta 1027, 158-167.Sciarrone, D., Schepis, A., Zoccali, M., Donato, P., Vita, F., Creti, D., Alpi, A., Mondello, L., 2018. Multidimensional gas chromatography coupled to combustion-isotope ratio mass spectrometry/quadrupole MS with a low-bleed ionic liquid secondary column for the authentication of truffles and products containing truffle. Analytical Chemistry 90, 6610-6617.Tranchida, P.Q., Aloisi, I., Giocastro, B., Mondello, L., 2018. Current state of comprehensive two-dimensional gas chromatography-mass spectrometry with focus on processes of ionization. TrAC Trends in Analytical Chemistry 105, 360-366.Xing, Y., Wang, M., Li, T., Fu, Y, x., Wang, X., 2018. Determination of polycyclic aromatic hydrocarbons in water samples by gas chromatography coupled to triple quadrupole tandem mass spectrometry using macroporous resin solid‐phase extraction. Journal of Separation Science 41, 2453-2460.Imaging: SEM, TEM, HIM, AFMAristov, A., Lelandais, B., Rensen, E., Zimmer, C., 2018. ZOLA-3D allows flexible 3D localization microscopy over an adjustable axial range. Nature Communications 9, Article 2409.Blom, J., Soenen, H., Katsiki, A., Van den Brande, N., Rahier, H., van den Bergh, W., 2018. Investigation of the bulk and surface microstructure of bitumen by atomic force microscopy. Construction and Building Materials 177, 158-169.Cao, G., Lin, M., Jiang, W., Zhao, W., Ji, L., Li, C., Lei, D., 2018. A statistical-coupled model for organic-rich shale gas transport. Journal of Petroleum Science and Engineering 169, 167-183.Chen, K., Zhang, T., Chen, X., He, Y., Liang, X., 2018. Model construction of micro-pores in shale: A case study of Silurian Longmaxi Formation shale in Dianqianbei area, SW China. Petroleum Exploration and Development 45, 412-421.Du, S., Pang, S., Shi, Y., 2018. A new and more precise experiment method for characterizing the mineralogical heterogeneity of unconventional hydrocarbon reservoirs. Fuel 232, 666-671.Ebeling, D., ?ekutor, M., Stiefermann, M., Tschakert, J., Dahl, J.E.P., Carlson, R.M.K., Schirmeisen, A., Schreiner, P.R., 2018. Assigning the absolute configuration of single aliphatic molecules by visual inspection. Nature Communications 9, Artcile 2420.Fang, Y., Xu, H., 2018. Study of an Ordovician carbonate with alternating dolomite–calcite laminations and its implication for catalytic effects of microbes on the formation of sedimentary dolomite. Journal of Sedimentary Research 88, 679-695.Fatayer, S., Coppola, A.I., Schulz, F., Walker, B.D., Broek, T.A., Meyer, G., Druffel, E.R.M., McCarthy, M., Gross, L., 2018. Direct visualization of individual aromatic compound structures in low molecular weight marine dissolved organic carbon. Geophysical Research Letters 45, 5590-5598.Girotto, G., China, S., Bhandari, J., Gorkowski, K., Scarnato, B.V., Capek, T., Marinoni, A., Veghte, D.P., Kulkarni, G., Aiken, A.C., Dubey, M., Mazzoleni, C., 2018. Fractal-like tar ball aggregates from wildfire smoke. Environmental Science & Technology Letters 5, 360–365.Hesketh, E.L., Saunders, K., Fisher, C., Potze, J., Stanley, J., Lomonossoff, G.P., Ranson, N.A., 2018. The 3.3?? structure of a plant geminivirus using cryo-EM. Nature Communications 9, Article 2369.Igder, M., Hosseinpour, N., Biyouki, A.A., Bahramian, A., 2018. Control of asphaltene aggregation in reservoir model oils along the production streamline by Fe3O4 and NiO nanoparticles. Energy & Fuels 32, 6689-6697.Javed, S.H., Zahir, A., Azhar, S., Hafeez, K., Abid, S., Nazir, A., Majeed, N., 2018. Physiochemical analysis of selected shale formations of Kohat region by advance characterization for oil potential evaluation. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 40, 1190-1198.Li, C., Ostadhassan, M., Gentzis, T., Kong, L., Carvajal-Ortiz, H., Bubach, B., 2018. Nanomechanical characterization of organic matter in the Bakken Formation by microscopy-based method. Marine and Petroleum Geology 96, 128-138.Liu, X., Zhang, J., Liu, Y., Huang, H., Liu, Z., 2018. Main factors controlling the wettability of gas shales: A case study of over-mature marine shale in the Longmaxi Formation. Journal of Natural Gas Science and Engineering 56, 18-28.Medina-Sandoval, C.F., Valencia-Dávila, J.A., Combariza, M.Y., Blanco-Tirado, C., 2018. Separation of asphaltene-stabilized water in oil emulsions and immiscible oil/water mixtures using a hydrophobic cellulosic membrane. Fuel 231, 297-306.Mudgil, D., Baskar, S., Baskar, R., Paul, D., Shouche, Y.S., 2018. Biomineralization potential of Bacillus subtilis, Rummeliibacillus stabekisii and Staphylococcus epidermidis strains in vitro isolated from speleothems, Khasi Hill Caves, Meghalaya, India. Geomicrobiology Journal 35, 675-694.Naveen, P., Asif, M., Ojha, K., 2018. Integrated fractal description of nanopore structure and its effect on CH4 adsorption on Jharia coals, India. Fuel 232, 190-204.Orberger, B., Delarue, V., Rodriguez, C., Salaün, A., Wallmach, T., Wirth, R., Boussafir, M., Dreux, G., Lafon, S., Schreiber, A., 2018. In-situ analyses of carbonaceous matter in manganiferous black shales: Analytical proxies and implication for ore processing. Minerals Engineering 125, 83-93.Othman, F., Yu, M., Kamali, F., Hussain, F., 2018. Fines migration during supercritical CO2 injection in sandstone. Journal of Natural Gas Science and Engineering 56, 344-357.Shao, X., Pang, X., Li, H., Hu, T., Xu, T., Xu, Y., Li, B., 2018. Pore network characteristics of lacustrine shales in the Dongpu Depression, Bohai Bay Basin, China, with implications for oil retention. Marine and Petroleum Geology 96, 457-473.Sobolev, I.S., Bredikhin, N.P., Bratec, T., Falk, A.Y., Tolkachev, O.S., Rikhvanov, L.P., Tishin, P.A., 2018. Chemical diagenesis in near-surface zone above oil fields in geochemical exploration. Applied Geochemistry 95, 33-44.Stranghoener, M., Schippers, A., Dultz, S., Behrens, H., 2018. Experimental microbial alteration and Fe mobilization from basaltic rocks of the ICDP HSDP2 Drill Core, Hilo, Hawaii. Frontiers in Microbiology 9, 1252. doi: 1210.3389/fmicb.2018.01252.Zhang, F., Ma, G., Tao, Y., Liu, X., Liu, Y., Li, R., 2018. Characteristics of hydraulic fracture surface based on 3D scanning technology. Royal Society Open Science 5, Article 171845.Zhang, H., Zhong, Y., She, J., Li, G., 2018. Characterization of shale matrix pore structure via experiment and model. Arabian Journal of Geosciences 11, Article 320.Zhang, L., Lu, S., Jiang, S., Xiao, D., Chen, L., Liu, Y., Zhang, Y., Li, B., Gong, C., 2018. Effect of shale lithofacies on pore structure of the Wufeng–Longmaxi Shale in southeast Chongqing, China. Energy & Fuels 32, 6603-6618.Zhang, N., Zhao, F., Guo, P., Li, J., Gong, W., Guo, Z., Sun, X., 2018. Nanoscale pore structure characterization and permeability of mudrocks and fine-grained sandstones in coal reservoirs by scanning electron microscopy, mercury intrusion porosimetry, and low-field nuclear magnetic resonance. Geofluids 2018, 20.Zhao, X., Wang, X., Shi, X., Tang, D., Shi, Q., 2018. Stepwise oxygenation of early Cambrian ocean controls early metazoan diversification. Palaeogeography, Palaeoclimatology, Palaeoecology 504, 86-103.Imaging: X-ray CTCole, J.M., Symes, D.R., Lopes, N.C., Wood, J.C., Poder, K., Alatabi, S., Botchway, S.W., Foster, P.S., Gratton, S., Johnson, S., Kamperidis, C., Kononenko, O., De Lazzari, M., Palmer, C.A.J., Rusby, D., Sanderson, J., Sandholzer, M., Sarri, G., Szoke-Kovacs, Z., Teboul, L., Thompson, J.M., Warwick, J.R., Westerberg, H., Hill, M.A., Norris, D.P., Mangles, S.P.D., Najmudin, Z., 2018. High-resolution μCT of a mouse embryo using a compact laser-driven X-ray betatron source. Proceedings of the National Academy of Sciences 115, 6335-6340.Du, S., Pang, S., Shi, Y., 2018. A new and more precise experiment method for characterizing the mineralogical heterogeneity of unconventional hydrocarbon reservoirs. Fuel 232, 666-671.Guo, C., Wang, X., Wang, H., He, S., Liu, H., Zhu, P., 2018. Effect of pore structure on displacement efficiency and oil-cluster morphology by using micro computed tomography (μCT) technique. Fuel 230, 430-439.Jiang, Y., Qin, C., Kang, Z., Zhou, J., Li, Y., Liu, H., Song, X., 2018. Experimental study of supercritical CO2 fracturing on initiation pressure and fracture propagation in shale under different triaxial stress conditions. Journal of Natural Gas Science and Engineering 55, 382-394.Lei, L., Seol, Y., Jarvis, K., 2018. Pore-scale visualization of methane hydrate-bearing sediments with micro-CT. Geophysical Research Letters 45, 5417-5426.Liu, J., Liang, W., Kang, Z., Lian, H., Geng, Y., 2018. Study on the quantitative model of oil shale porosity in the pyrolysis process based on pyrolysis kinetics Oil Shale 35, 128–143.Naveen, P., Asif, M., Ojha, K., 2018. Integrated fractal description of nanopore structure and its effect on CH4 adsorption on Jharia coals, India. Fuel 232, 190-204.Panahi, H., Kobchenko, M., Meakin, P., Dysthe, D.K., Renard, F., 2018. In-situ imaging of fracture development during maturation of an organic-rich shale: Effects of heating rate and confinement. Marine and Petroleum Geology 95, 314-327.Quigley, M.Y., Negassa, W.C., Guber, A.K., Rivers, M.L., Kravchenko, A.N., 2018. Influence of pore characteristics on the fate and distribution of newly added carbon. Frontiers in Environmental Science 6, 51. doi: 10.3389/fenvs.2018.00051.Schmitt Rahner, M., Halisch, M., Peres Fernandes, C., Weller, A., Sampaio Santiago dos Santos, V., 2018. Fractal dimensions of pore spaces in unconventional reservoir rocks using X-ray nano- and micro-computed tomography. Journal of Natural Gas Science and Engineering 55, 298-311.Shi, F., Liu, H., Rodrigues, S., Esterle, J., Nguyen, A.K., Manlapig, E., 2018. Lithotype-based modelling and simulations of coal degradation conditioned by both high and low energy breakage. Fuel 232, 405-414.Sim?es, T.R., Caldwell, M.W., Ta?anda, M., Bernardi, M., Palci, A., Vernygora, O., Bernardini, F., Mancini, L., Nydam, R.L., 2018. The origin of squamates revealed by a Middle Triassic lizard from the Italian Alps. Nature 557, 706-709.Tan, Y., Pan, Z., Liu, J., Zhou, F., Connell, L.D., Sun, W., Haque, A., 2018. Experimental study of impact of anisotropy and heterogeneity on gas flow in coal. Part II: Permeability. Fuel 230, 397-409.Wang, X., White, S.C., Balisi, M., Biewer, J., Sankey, J., Garber, D., Tseng, Z.J., 2018. First bone-cracking dog coprolites provide new insight into bone consumption in Borophagus and their unique ecological niche. eLife 7, Article e34773.Zhang, G., Ranjith, P.G., Perera, M.S.A., Haque, A., Choi, X., Sampath, K.S.M., 2018. Characterization of coal porosity and permeability evolution by demineralisation using image processing techniques: A micro-computed tomography study. Journal of Natural Gas Science and Engineering 56, 384-396.Liquid Chromatography/LC-MS/SFCBajtai, A., Lajkó, G., Szatmári, I., Fül?p, F., Lindner, W., Ilisz, I., Péter, A., 2018. Dedicated comparisons of diverse polysaccharide- and zwitterionic Cinchona alkaloid-based chiral stationary phases probed with basic and ampholytic indole analogs in liquid and subcritical fluid chromatography mode. Journal of Chromatography A 1563, 180-190.Desfontaine, V., Losacco, G.L., Gagnebin, Y., Pezzatti, J., Farrell, W.P., González-Ruiz, V., Rudaz, S., Veuthey, J.-L., Guillarme, D., 2018. Applicability of supercritical fluid chromatography – mass spectrometry to metabolomics. I – Optimization of separation conditions for the simultaneous analysis of hydrophilic and lipophilic substances. Journal of Chromatography A 1562, 96-107.Haghighi, F., Talebpour, Z., Nezhad, A.S., 2018. Towards fully integrated liquid chromatography on a chip: Evolution and evaluation. TrAC Trends in Analytical Chemistry 105, 302-337.Kalambet, Y., Kozmin, Y., Samokhin, A., 2018. Comparison of integration rules in the case of very narrow chromatographic peaks. Chemometrics and Intelligent Laboratory Systems 179, 22-30.Liu, M., Huang, X., Liu, Q., Chen, M., Liao, S., Zhu, F., Shi, S., Yang, H., Chen, X., 2018. Rapid screening and identification of antioxidants in the leaves of Malus hupehensis using off‐line two‐dimensional HPLC–UV–MS/MS coupled with a 1,1′‐diphenyl‐2‐picrylhydrazyl assay. Journal of Separation Science 41, 2536-2543.Ndiripo, A., Pasch, H., 2018. Comprehensive analysis of oxidized waxes by solvent and thermal gradient interaction chromatography and two-dimensional liquid chromatography. Analytical Chemistry 90, 7626-7634.Ohira, S.-I., Kaneda, K., Matsuzaki, T., Mori, S., Mori, M., Toda, K., 2018. Universal HPLC detector for hydrophilic organic compounds by means of total organic carbon detection. Analytical Chemistry 90, 6461-6467.Parr, M.K., Wüst, B., Teubel, J., Joseph, J.F., 2018. Splitless hyphenation of SFC with MS by APCI, APPI, and ESI exemplified by steroids as model compounds. Journal of Chromatography B 1091, 67-78.Poole, C.F., 2018. Chromatographic test methods for characterizing alkylsiloxane-bonded silica columns for reversed-phase liquid chromatography. Journal of Chromatography B 1092, 207-219.Pursch, M., Wegener, A., Buckenmaier, S., 2018. Evaluation of active solvent modulation to enhance two-dimensional liquid chromatography for target analysis in polymeric matrices. Journal of Chromatography A 1562, 78-86.Santerre, C., Vallet, N., Touboul, D., 2018. Fingerprints of flower absolutes using supercritical fluid chromatography hyphenated with high resolution mass spectrometry. Journal of Chromatography B 1092, 1-6.Woiwode, U., Neubauer, S., Lindner, W., Buckenmaier, S., L?mmerhofer, M., 2018. Enantioselective multiple heartcut two-dimensional ultra-high-performance liquid chromatography method with a Coreshell chiral stationary phase in the second dimension for analysis of all proteinogenic amino acids in a single run. Journal of Chromatography A 1562, 69-77.Yang, P., Bai, L., Wang, W., Rabasco, J., 2018. Analysis of hydrophobically modified ethylene oxide urethane rheology modifiers by comprehensive two dimensional liquid chromatography. Journal of Chromatography A 1560, 55-62.Mass Spectroscopy/ICR-FTMS/OrbitrapChen, M., Jung, J., Lee, Y.K., Hur, J., 2018. Surface accumulation of low molecular weight dissolved organic matter in surface waters and horizontal off-shelf spreading of nutrients and humic-like fluorescence in the Chukchi Sea of the Arctic Ocean. Science of The Total Environment 639, 624-632.Graham, E.B., Crump, A.R., Kennedy, D.W., Arntzen, E., Fansler, S., Purvine, S.O., Nicora, C.D., Nelson, W., Tfaily, M.M., Stegen, J.C., 2018. Multi 'omics comparison reveals metabolome biochemistry, not microbiome composition or gene expression, corresponds to elevated biogeochemical function in the hyporheic zone. Science of The Total Environment 642, 742-753.Heidke, I., Scholz, D., Hoffmann, T., 2018. Quantification of lignin oxidation products as vegetation biomarkers in speleothems and cave drip water Biogeosciences Discussions 2018, 1-23.Heninger, M., Mestdagh, H., Louarn, E., Mauclaire, G., Boissel, P., Leprovost, J., Bauchard, E., Thomas, S., Lemaire, J., 2018. Gas analysis by electron ionization combined with chemical ionization in a compact FTICR mass spectrometer. Analytical Chemistry 90, 7517-7525.Leshuk, T., Peru, K.M., de Oliveira Livera, D., Tripp, A., Bardo, P., Headley, J.V., Gu, F., 2018. Petroleomic analysis of the treatment of naphthenic organics in oil sands process-affected water with buoyant photocatalysts. Water Research 141, 297-306.Liu, W., Liao, Y., Pan, Y., Jiang, B., Zeng, Q., Shi, Q., Hsu, C.S., 2018. Use of ESI FT–ICR MS to investigate molecular transformation in simulated aerobic biodegradation of a sulfur-rich crude oil. Organic Geochemistry 123, 17-26.Maillard, J., Carrasco, N., Schmitz-Afonso, I., Gautier, T., Afonso, C., 2018. Comparison of soluble and insoluble organic matter in analogues of Titan's aerosols. Earth and Planetary Science Letters 495, 185-191.Powers, L.C., Luek, J.L., Schmitt-Kopplin, P., Campbell, B.J., Magen, C., Cooper, L.W., Gonsior, M., 2018. Seasonal changes in dissolved organic matter composition in Delaware Bay, USA in March and August 2014. Organic Geochemistry 122, 87-97.Rampler, E., Criscuolo, A., Zeller, M., El Abiead, Y., Schoeny, H., Hermann, G., Sokol, E., Cook, K., Peake, D.A., Delanghe, B., Koellensperger, G., 2018. A novel lipidomics workflow for improved human plasma identification and quantification using RPLC-MSn methods and isotope dilution strategies. Analytical Chemistry 90, 6494-6501.Reynolds, L.L., Lajtha, K., Bowden, R.D., Tfaily, M.M., Johnson, B.R., Bridgham, S.D., 2018. The path from litter to soil: Insights into soil C cycling from long‐term input manipulation and high‐resolution mass spectrometry. Journal of Geophysical Research: Biogeosciences 123, 1486-1497.Trapp, J., Gouveia, D., Almunia, C., Pible, O., Degli Esposti, D., Gaillard, J.-C., Chaumot, A., Geffard, O., Armengaud, J., 2018. Digging deeper into the pyriproxyfen-response of the amphipod Gammarus fossarum with a next-generation ultra-high-field Orbitrap analyser: new perspectives for environmental toxicoproteomics. Frontiers in Environmental Science 6, 54. doi: 10.3389/fenvs.2018.0005.Valencia-Dávila, J.A., Witt, M., Blanco-Tirado, C., Combariza, M.Y., 2018. Molecular characterization of naphthenic acids from heavy crude oils using MALDI FT-ICR mass spectrometry. Fuel 231, 126-133.Wang, X., Cai, T., Wen, W., Zhang, Z., 2018. Effect of biosurfactant on biodegradation of heteroatom compounds in heavy oil. Fuel 230, 418-429.Wang, Y., Spencer, R.G.M., Podgorski, D., Kellerman, A., Rashid, H., Zito, P., Xiao, W., Wei, D., Yang, Y., Xu, Y., 2018. Spatiotemporal transformation of dissolved organic matter along an alpine stream flowpath on the Qinghai-Tibetan Plateau: importance of source and permafrost degradation. Biogeosciences Discussions 2018, 1-34.Zhang, Y.-L., Gong, C., Pei, X.-L., Han, Y.-L., Huang, Y.-Y., Xu, X., 2018. Rapid quantitative determination of triglycerides in edible oils by matrix-assisted laser desorption/ionisation Fourier transform ion cyclotron resonance mass spectrometry using pencil graphite combined with 2,5-dihydroxybenzoic acid as matrix. International Journal of Mass Spectrometry 431, 56-62.Mass Spectroscopy/OtherAl-Kaabi, N., Al-Ghouti, M.A., Oualha, M., Mohammad, M.Y., Al-Naemi, A., S?lling, T.I., Al-Shamari, N., Zouari, N., 2018. A MALDI-TOF study of bio-remediation in highly weathered oil contaminated soils. Journal of Petroleum Science and Engineering 168, 569-576.Amo-González, M., Carnicero, I., Pérez, S., Delgado, R., Eiceman, G.A., Fernández de la Mora, G., Fernández de la Mora, J., 2018. Ion mobility spectrometer-fragmenter-ion mobility spectrometer analogue of a triple quadrupole for high-resolution ion analysis at atmospheric pressure. Analytical Chemistry 90, 6885-6892.Calvano, C.D., Monopoli, A., Cataldi, T.R.I., Palmisano, F., 2018. MALDI matrices for low molecular weight compounds: an endless story? Analytical and Bioanalytical Chemistry 410, 4015-4038.Duncan, K.D., Fang, R., Yuan, J., Chu, R.K., Dey, S.K., Burnum-Johnson, K.E., Lanekoff, I., 2018. Quantitative mass spectrometry imaging of prostaglandins as silver ion adducts with nanospray desorption electrospray ionization. Analytical Chemistry 90, 7246-7252.Giuliani, A., Williams, J.P., Green, M.R., 2018. Extreme ultraviolet radiation: A means of ion activation for tandem mass spectrometry. Analytical Chemistry 90, 7176-7180.Hoffmann, F., Jaeger, C., Bhattacharya, A., Schmitt, C.A., Lisec, J., 2018. Nontargeted identification of tracer incorporation in high-resolution mass spectrometry. Analytical Chemistry 90, 7253-7260.Kraková, L., ?oltys, K., Otlewska, A., Pietrzak, K., Purkrtová, S., Savická, D., Pu?kárová, A., Bu?ková, M., Szemes, T., Budi?, J., Demnerová, K., Gutarowska, B., Pangallo, D., 2018. Comparison of methods for identification of microbial communities in book collections: Culture-dependent (sequencing and MALDI-TOF MS) and culture-independent (Illumina MiSeq). International Biodeterioration & Biodegradation 131, 51-59.Montes-Bayón, M., Sharar, M., Corte-Rodriguez, M., 2018. Trends on (elemental and molecular) mass spectrometry based strategies for speciation and metallomics. TrAC Trends in Analytical Chemistry 104, 4-10.Reddy, S.B., Pavankumar, P., Sridhar, L., Saha, S., Narahari, S., G., Prabhakar, S., 2018. Differential cationization of fatty acids with monovalent cations studied by electrospray ionization tandem mass spectrometry and a computational approach. Rapid Communications in Mass Spectrometry 32, 1126-1134.Shelley, J.T., Badal, S.P., Engelhard, C., Hayen, H., 2018. Ambient desorption/ionization mass spectrometry: evolution from rapid qualitative screening to accurate quantification tool. Analytical and Bioanalytical Chemistry 410, 4061-4076.Yin, R., Kyle, J., Burnum-Johnson, K., Bloodsworth, K.J., Sussel, L., Ansong, C., Laskin, J., 2018. High spatial resolution imaging of mouse pancreatic islets using nanospray desorption electrospray ionization mass spectrometry. Analytical Chemistry 90, 6548-6555.Metabolomics/LipidomicsBatarseh, A.M., Abbott, S.K., Duchoslav, E., Alqarni, A., Blanksby, S.J., Mitchell, T.W., 2018. Discrimination of isobaric and isomeric lipids in complex mixtures by combining ultra-high pressure liquid chromatography with collision and ozone-induced dissociation. International Journal of Mass Spectrometry 431, 27-36.Chou, L., Kenig, F., Murray, A.E., Fritsen, C.H., Doran, P.T., 2018. Effects of legacy metabolites from previous ecosystems on the environmental metabolomics of the brine of Lake Vida, East Antarctica. Organic Geochemistry 122, 161-170.Desfontaine, V., Losacco, G.L., Gagnebin, Y., Pezzatti, J., Farrell, W.P., González-Ruiz, V., Rudaz, S., Veuthey, J.-L., Guillarme, D., 2018. Applicability of supercritical fluid chromatography – mass spectrometry to metabolomics. I – Optimization of separation conditions for the simultaneous analysis of hydrophilic and lipophilic substances. Journal of Chromatography A 1562, 96-107.Evans, E.M., Freund, D.M., Sondervan, V.M., Cohen, J.D., Hegeman, A.D., 2018. Metabolic patterns in Spirodela polyrhiza revealed by 15N stable isotope labeling of amino acids in photoautotrophic, heterotrophic, and mixotrophic growth conditions. Frontiers in Chemistry 6, 191. doi: 110.3389/fchem.2018.00191.Fu, T., Touboul, D., Della-Negra, S., Hou?l, E., Amusant, N., Duplais, C., Fisher, G.L., Brunelle, A., 2018. 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Proceedings of the National Academy of Sciences 115, 6428-6433.Bruger, E.L., Marx, C.J., 2018. A decade of genome sequencing has revolutionized studies of experimental evolution. Current Opinion in Microbiology 45, 149-155.Chandru, K., Guttenberg, N., Giri, C., Hongo, Y., Butch, C., Mamajanov, I., Cleaves, H.J., 2018. Simple prebiotic synthesis of high diversity dynamic combinatorial polyester libraries. Communications Chemistry 1, Article 30.Dohm, J.M., Maruyama, S., Kido, M., Baker, V.R., 2018. A possible anorthositic continent of early Mars and the role of planetary size for the inception of Earth-like life. Geoscience Frontiers 9, 1085-1098.Gunde-Cimerman, N., Plemenita?, A., Oren, A., 2018. Strategies of adaptation of microorganisms of the three domains of life to high salt concentrations. FEMS Microbiology Reviews 42, 353-375.Higashi, K., Kawai, Y., Baba, T., Kurokawa, K., Oshima, T., 2018. Essential cellular modules for the proliferation of the primitive cell. 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Journal of Earth Science 29, 556-563.Wang, Y., Liu, L., Ji, H., Song, G., Luo, Z., Li, X., Xu, T., Li, L., 2018. Origin and accumulation of crude oils in Triassic reservoirs of Wuerhe-Fengnan area (WFA) in Junggar Basin, NW China: Constraints from molecular and isotopic geochemistry and fluid inclusion analysis. Marine and Petroleum Geology 96, 71-93.Xu, F., Yuan, H., Xu, G., Luo, X., 2018. Fluid charging and hydrocarbon accumulation in the Cambrian Longwangmiao Formation of Moxi Structure, Sichuan Basin, SW China. Petroleum Exploration and Development 45, 442-451.General InterestAle-Agha, N., Goy, C., Jakobs, P., Spyridopoulos, I., Gonnissen, S., Dyballa-Rukes, N., Aufenvenne, K., von Ameln, F., Zurek, M., Spannbrucker, T., Eckermann, O., Jakob, S., Gorressen, S., Abrams, M., Grandoch, M., Fischer, J.W., K?hrer, K., Deenen, R., Unfried, K., Altschmied, J., Haendeler, J., 2018. 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Geochemistry International 56, 554-565.Giraldo-Gómez, V.M., Beik, I., Podlaha, O.G., Mutterlose, J., 2018. A paleoenvironmental analyses of benthic foraminifera from Upper Cretaceous – Lower Paleocene oil shales of Jordan. Cretaceous Research 91, 1-13.Hakimi, M.H., Al-Matary, A.M., Salad Hersi, O., 2018. Late Jurassic bituminous shales from Marib oilfields in the Sabatayn Basin (NW Yemen): Geochemical and petrological analyses reveal oil-shale resource. Fuel 232, 530-542.He, T., Lu, S., Li, W., Tan, Z., Zhang, X., 2018. Effect of salinity on source rock formation and its control on the oil content in shales in the Hetaoyuan Formation from the Biyang Depression, Nanxiang Basin, Central China. Energy & Fuels 32, 6698-6707.Igisu, M., Yokoyama, T., Ueno, Y., Nakashima, S., Shimojima, M., Ohta, H., Maruyama, S., 2018. Changes of aliphatic C–H bonds in cyanobacteria during experimental thermal maturation in the presence or absence of silica as evaluated by FTIR microspectroscopy. 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Organic porosity: A geochemist's view of the current state of understanding. Organic Geochemistry 123, 1-16.Kosakowski, P., Koltun, Y., Machowski, G., Poprawa, P., Papiernik, B., 2018. The geochemical characteristics of the Oligocene – Lower Miocene Menilite Formation in the Polish and Ukrainian Outer Carpathians: A review. Journal of Petroleum Geology 41, 319-335.Kotla, S.S., Patnaik, R., Sehgal, R.K., Kharya, A., 2018. Isotopic evidence for ecological and climate change in the richly fossiliferous Plio-Pleistocene Upper Siwalik deposits exposed around Chandigarh, India. Journal of Asian Earth Sciences 163, 32-42.Lapidus, A.L., Kerimov, V.Y., Mustaev, R.N., Movsumzade, E.M., Zakharchenko, M.V., 2018. Caucasus Maykopian kerogenous shale sequences: Generative potential. Oil Shale 35, 113–127.Li, C., Ostadhassan, M., Gentzis, T., Kong, L., Carvajal-Ortiz, H., Bubach, B., 2018. Nanomechanical characterization of organic matter in the Bakken Formation by microscopy-based method. Marine and Petroleum Geology 96, 128-138.Liu, S., Wu, C., Li, T., Wang, H., 2018. Multiple geochemical proxies controlling the organic matter accumulation of the marine-continental transitional shale: A case study of the Upper Permian Longtan Formation, western Guizhou, China. Journal of Natural Gas Science and Engineering 56, 152-165.Maaten, B., Pikkor, H., Konist, A., Siirde, A., 2018. Determination of the total sulphur content of oil shale by using different analytical methods. Oil Shale 35, 144–153.Meilijson, A., Ashckenazi-Polivoda, S., Illner, P., Speijer, R.P., Almogi-Labin, A., Feinstein, S., Püttmann, W., Abramovich, S., 2018. From phytoplankton to oil shale reservoirs: A 19-million-year record of the Late Cretaceous Tethyan upwelling regime in the Levant Basin. Marine and Petroleum Geology 95, 188-205.Mirshahani, M., Bahrami, H., Rashidi, M., Tarhandeh, E., Khani, B., 2018. Organic geochemical evaluation of potential Cenozoic source rocks in the Moghan Basin, NW Iran: Implications for hydrocarbon exploration. Journal of Petroleum Geology 41, 393-410.Mishra, S., Singh, V.P., 2018. Palynology, palynofacies, and taphonomical studies of Kamthi Formation, (Godavari Graben), southern India: Implications to biostratigraphy, palaeoecology, and depositional environment. International Journal of Coal Geology 195, 102-124.Peng, J., Pang, X., Shi, H., Peng, H., Xiao, S., 2018. Hydrocarbon-generation potential of Upper Eocene Enping Formation mudstones in the Huilu area, northern Pearl River Mouth Basin, South China Sea. American Association of Petroleum Geologists Bulletin 102, 1323-1342.Ponsaing, L., Bojesen-Koefoed, J.A., Thomsen, E., Stemmerik, L., 2018. Temporal organic facies variations of Upper Jurassic - lowermost Cretaceous source rocks in the Danish Central Graben, North Sea. International Journal of Coal Geology 195, 217-237.Pupp, M., Bechtel, A., ?ori?, S., Gratzer, R., Rustamov, J., Sachsenhofer, R.F., 2018. Eocene and Oligo‐Miocene source rocks in the Rioni and Kura basins of Georgia: Depositional environment and petroleum potential. Journal of Petroleum Geology 41, 367-392.Reolid, J., Betzler, C., 2018. Ichnofabric logs for the characterization of the organic content in carbonates. Marine and Petroleum Geology 95, 246-254.Sachsenhofer, R.F., Popov, S.V., Coric, S., Mayer, J., Misch, D., Morton, M.T., Pupp, M., Rauball, J., Tari, G., 2018. Paratethyan petroleum source rocks: An overview. Journal of Petroleum Geology 41, 219-245.Tang, X., Zhang, J., Jiang, Z., Zhang, R., Lan, C., Zhao, W., Zhu, J., Wang, J., Zhao, P., 2018. Heterogeneity of organic-rich lacustrine marlstone succession and their controls to petroleum expulsion, retention, and migration: A case study in the Shulu Sag, Bohai Bay Basin, China. Marine and Petroleum Geology 96, 166-178.Wang, Y., Li, X., Chen, B., Wu, W., Dong, D., Zhang, J., Han, J., Ma, J., Dai, B., Wang, H., Jiang, S., 2018. Lower limit of thermal maturity for the carbonization of organic matter in marine shale and its exploration risk. Petroleum Exploration and Development 45, 402-411.Washburn, A.M., Hudson, S.M., Selby, D., Abdullayev, N., Shiyanova, N., 2018. Re‐Os geochronology and chemostratigraphy of the Maikop series source rocks of eastern Azerbaijan. Journal of Petroleum Geology 41, 411-416.Xiao, Z., Tan, J., Ju, Y., Hilton, J., Yang, R., Zhou, P., Huang, Y., Ning, B., Liu, J., 2018. Natural gas potential of Carboniferous and Permian transitional shales in central Hunan, South China. Journal of Natural Gas Science and Engineering 55, 520-533.Xu, C., Liu, C., Guo, P., Li, M., Huang, L., Zhao, Y., Pan, Y., Zhang, Y., 2018. Geochemical characteristics and their geological significance of intrasalt mudstones from the Paleogene Qianjiang Formation in the Qianjiang Graben, Jianghan Basin, China. Acta Sedimentologica Sinica 36, 617-629.Xu, Q., Qiu, N., Liu, W., Shen, A., Wang, X., 2018. Thermal evolution and maturation of Sinian and Cambrian source rocks in the central Sichuan Basin, Southwest China. Journal of Asian Earth Sciences 164, 143-158.Yurchenko, I.A., Moldowan, J.M., Peters, K.E., Magoon, L.B., Graham, S.A., 2018. The role of calcareous and shaly source rocks in the composition of petroleum expelled from the Triassic Shublik Formation, Alaska North Slope. Organic Geochemistry 122, 52-67.Zhang, J., Li, X., Zhang, X., Zhang, M., Cong, G., Zhang, G., Wang, F., 2018. Geochemical and geological characterization of marine–continental transitional shales from Longtan Formation in Yangtze area, South China. Marine and Petroleum Geology 96, 1-15.Zhang, L., Li, B., Jiang, S., Xiao, D., Lu, S., Zhang, Y., Gong, C., Chen, L., 2018. Heterogeneity characterization of the lower Silurian Longmaxi marine shale in the Pengshui area, South China. International Journal of Coal Geology 195, 250-266.Zhang, M., Li, Z., Yin, J., 2018. Sedimentary and geochemical characteristics of oil shale in the Permian Lucaogou Formation in the southeastern Junggar Basin, northwest China: Implications for sedimentary environments Oil Shale 35, 97–112.Unconventional ResourcesCao, G., Lin, M., Jiang, W., Zhao, W., Ji, L., Li, C., Lei, D., 2018. A statistical-coupled model for organic-rich shale gas transport. Journal of Petroleum Science and Engineering 169, 167-183.Chen, J., Li, W., Ni, Y., Dai, X., Liang, D., Deng, C., Bian, L., 2018. The Permian source rocks and their natural gas prospects in the Sichuan Basin (II): The geochemical characteristics of source rocks and the potential of natural gas resource. Natural Gas Industry 38, 33-45.Chen, K., Zhang, T., Chen, X., He, Y., Liang, X., 2018. Model construction of micro-pores in shale: A case study of Silurian Longmaxi Formation shale in Dianqianbei area, SW China. Petroleum Exploration and Development 45, 412-421.Chen, T., Feng, X.-T., Pan, Z., 2018. Experimental study on kinetic swelling of organic-rich shale in CO2, CH4 and N2. Journal of Natural Gas Science and Engineering 55, 406-417.Du, S., Pang, S., Shi, Y., 2018. A new and more precise experiment method for characterizing the mineralogical heterogeneity of unconventional hydrocarbon reservoirs. Fuel 232, 666-671.Fan, K., Li, Y., Elsworth, D., Dong, M., Yin, C., Li, Y., Chen, Z., 2018. Three stages of methane adsorption capacity affected by moisture content. Fuel 231, 352-360.Geng, L., Li, G., Wang, M., Li, Y., Tian, S., Pang, W., Lyu, Z., 2018. A fractal production prediction model for shale gas reservoirs. Journal of Natural Gas Science and Engineering 55, 354-367.Guo, C., Wang, X., Wang, H., He, S., Liu, H., Zhu, P., 2018. Effect of pore structure on displacement efficiency and oil-cluster morphology by using micro computed tomography (μCT) technique. Fuel 230, 430-439.Hao, Y., Wang, W., Yuan, B., Su, Y., An, J., Shu, H., 2018. Shale gas simulation considering natural fractures, gas desorption, and slippage flow effects using conventional modified model. Journal of Petroleum Exploration and Production Technology 8, 607-615.Huang, D., Duan, Y., Yang, G., Yan, W., Wei, T., Zou, J., Wang, W., Li, Y., 2018. Controlling effect of source-reservoir configuration model on tight oil enrichment in freshwater lacustrine sedimentary area:a case study of the Jurassic Da’anzhai Member in Sichuan Basin. Acta Petrolei Sinica 39, 518-527.Huang, H., Sun, W., Xiong, F., Chen, L., Li, X., Gao, T., Jiang, Z., Ji, W., Wu, Y., Han, J., 2018. A novel method to estimate subsurface shale gas capacities. Fuel 232, 341-350.Huang, S., Wu, Y., Cheng, L., Liu, H., Xue, Y., Ding, G., 2018. Apparent permeability model for shale gas reservoirs considering multiple transport mechanisms. Geofluids 2018, Article 2186194.Ishii, E., 2018. Assessment of hydraulic connectivity of fractures in mudstones by single-borehole investigations. Water Resources Research 54, 3335-3356.Jiang, F., Wang, Q., Liu, L., Gao, X., Hu, T., 2018. Geological and geochemical characteristics of the Middle–Lower Jurassic shales in the Kuqa Depression, Tarim Basin: an evaluation of shale gas resources. Australian Journal of Earth Sciences 65, 557-573.Jiang, Y., Qin, C., Kang, Z., Zhou, J., Li, Y., Liu, H., Song, X., 2018. Experimental study of supercritical CO2 fracturing on initiation pressure and fracture propagation in shale under different triaxial stress conditions. Journal of Natural Gas Science and Engineering 55, 382-394.Kamari, A., Li, L., Sheng, J.J., 2018. Effects of rock pore sizes on the PVT properties of oil and gas-condensates in shale and tight reservoirs. Petroleum 4, 148-157.Katz, B.J., Arango, I., 2018. Organic porosity: A geochemist's view of the current state of understanding. Organic Geochemistry 123, 1-16.Kumari, W.G.P., Ranjith, P.G., Perera, M.S.A., Li, X., Li, L.H., Chen, B.K., Isaka, B.L.A., De Silva, V.R.S., 2018. Hydraulic fracturing under high temperature and pressure conditions with micro CT applications: Geothermal energy from hot dry rocks. Fuel 230, 138-154.Li, Q., Pang, X., Tang, L., Chen, G., Shao, X., Jia, N., 2018. Occurrence features and gas content analysis of marine and continental shales: A comparative study of Longmaxi Formation and Yanchang Formation. Journal of Natural Gas Science and Engineering 56, 504-522.Li, X., Zhang, J., Wang, Y., Guo, M., Wang, Z., Wang, F., 2018. Accumulation condition and favorable area evaluation of shale gas from the?Niutitang Formation in northern Guizhou, South China. Journal of Natural Gas Geoscience 3, 1-10.Liu, J., Liang, W., Kang, Z., Lian, H., Geng, Y., 2018. Study on the quantitative model of oil shale porosity in the pyrolysis process based on pyrolysis kinetics Oil Shale 35, 128–143.Liu, K., Ostadhassan, M., Kong, L., 2018. Multifractal characteristics of Longmaxi Shale pore structures by N2 adsorption: A model comparison. Journal of Petroleum Science and Engineering 168, 330-341.Liu, X., Zhang, J., Liu, Y., Huang, H., Liu, Z., 2018. Main factors controlling the wettability of gas shales: A case study of over-mature marine shale in the Longmaxi Formation. Journal of Natural Gas Science and Engineering 56, 18-28.Liu, Y., Tang, X., Zhang, J., Mo, X., Huang, H., Liu, Z., 2018. Geochemical characteristics of the extremely high thermal maturity transitional shale gas in the Southern North China Basin (SNCB) and its differences with marine shale gas. International Journal of Coal Geology 194, 33-44.Liu, Y., Zhu, Y., Liu, S., Li, W., 2018. A hierarchical methane adsorption characterization through a multiscale approach by considering the macromolecular structure and pore size distribution. Marine and Petroleum Geology 96, 304-314.Lovell, A.E., Srinivasan, S., Karra, S., O'Malley, D., Makedonska, N., Viswanathan, H.S., Srinivasan, G., Carey, J.W., Frash, L.P., 2018. Extracting hydrocarbon from shale: An investigation of the factors that influence the decline and the tail of the production curve. Water Resources Research 54, 3748-3757.Lu, S., Li, J., Zhang, P., Xue, H., Wang, G., Zhang, J., Liu, H., Li, Z., 2018. Classification of microscopic pore-throats and the grading evaluation on shale oil reservoirs. Petroleum Exploration and Development 45, 452-460.Meshalkin, Y., Koroteev, D., Popov, E., Chekhonin, E., Popov, Y., 2018. Robotized petrophysics: Machine learning and thermal profiling for automated mapping of lithotypes in unconventionals. Journal of Petroleum Science and Engineering 167, 944-948.Miao, Y., Li, X., Lee, J., Zhou, Y., Liu, S., Chang, Y., Wang, S., 2018. Characterization of hydrocarbon/pores generation and methane adsorption in shale organic matter. Petroleum Science and Technology 36, 1187-1193.Panahi, H., Kobchenko, M., Meakin, P., Dysthe, D.K., Renard, F., 2018. In-situ imaging of fracture development during maturation of an organic-rich shale: Effects of heating rate and confinement. Marine and Petroleum Geology 95, 314-327.Schmitt Rahner, M., Halisch, M., Peres Fernandes, C., Weller, A., Sampaio Santiago dos Santos, V., 2018. Fractal dimensions of pore spaces in unconventional reservoir rocks using X-ray nano- and micro-computed tomography. Journal of Natural Gas Science and Engineering 55, 298-311.Senger, R., Romero, E., Marschall, P., 2018. Modeling of gas migration through low-permeability clay rock using information on pressure and deformation from fast air injection tests. Transport in Porous Media 123, 563-579.Shao, X., Pang, X., Li, H., Hu, T., Xu, T., Xu, Y., Li, B., 2018. Pore network characteristics of lacustrine shales in the Dongpu Depression, Bohai Bay Basin, China, with implications for oil retention. Marine and Petroleum Geology 96, 457-473.Shen, W., Zheng, L., Oldenburg, C.M., Cihan, A., Wan, J., Tokunaga, T.K., 2018. Methane diffusion and adsorption in shale rocks: A numerical study using the dusty gas model in TOUGH2/EOS7C-ECBM. Transport in Porous Media 123, 521-531.Su, S., Jiang, Z., Shan, X., Zhu, Y., Wang, P., Luo, X., Li, Z., Zhu, R., Wang, X., 2018. The wettability of shale by NMR measurements and its controlling factors. Journal of Petroleum Science and Engineering 169, 309-316.Tathed, P., Han, Y., Misra, S., 2018. Hydrocarbon saturation in Bakken Petroleum System based on joint inversion of resistivity and dielectric dispersion logs. Fuel 233, 45-55.Wan, T., Mu, Z., 2018. The use of numerical simulation to investigate the enhanced Eagle Ford shale gas condensate well recovery using cyclic CO2 injection method with nano-pore effect. Fuel 233, 123-132.Wang, G., Wang, K., Wang, S., Elsworth, D., Jiang, Y., 2018. An improved permeability evolution model and its application in fractured sorbing media. Journal of Natural Gas Science and Engineering 56, 222-232.Wang, S., Shi, J., Wang, K., Sun, Z., Miao, Y., Hou, C., 2018. Apparent permeability model for gas transport in shale reservoirs with nano-scale porous media. Journal of Natural Gas Science and Engineering 55, 508-519.Wang, X., Guo, C., He, S., Jiang, Z., Ma, Y., 2018. Improved skeleton extraction method considering surface feature of natural micro fractures in unconventional shale/tight reservoirs. Journal of Petroleum Science and Engineering 168, 521-532.Wang, Y., Liu, S., Zhao, Y., 2018. Modeling of permeability for ultra-tight coal and shale matrix: A multi-mechanistic flow approach. Fuel 232, 60-70.Wei, M., Liu, J., Elsworth, D., Wang, E., 2018. Triple-porosity modelling for the simulation of multiscale flow mechanisms in shale reservoirs. Geofluids 2018, Article 6948726.Yuan, Y., Rezaee, R., Verrall, M., Hu, S.-Y., Zou, J., Testmanti, N., 2018. Pore characterization and clay bound water assessment in shale with a combination of NMR and low-pressure nitrogen gas adsorption. International Journal of Coal Geology 194, 11-21.Zeng, Q., Chen, S., He, P., Yang, Q., Guo, X., Chen, P., Dai, C., Li, X., Gai, S., Deng, Y., Hou, H., 2018. Quantitative prediction of shale gas sweet spots based on seismic data in Lower Silurian Longmaxi Formation, Weiyuan area, Sichuan Basin, SW China. Petroleum Exploration and Development 45, 422-430.Zhang, C., Wang, X., Zhu, L., 2018. Estimation of total porosity in shale formations from element capture logging and conventional logging data. Arabian Journal of Geosciences 11, 264.Zhang, F., Ma, G., Tao, Y., Liu, X., Liu, Y., Li, R., 2018. Characteristics of hydraulic fracture surface based on 3D scanning technology. Royal Society Open Science 5, Article 171845.Zhang, H., Zhong, Y., She, J., Li, G., 2018. Characterization of shale matrix pore structure via experiment and model. Arabian Journal of Geosciences 11, Article 320.Zhang, L., Lu, S., Jiang, S., Xiao, D., Chen, L., Liu, Y., Zhang, Y., Li, B., Gong, C., 2018. Effect of shale lithofacies on pore structure of the Wufeng–Longmaxi Shale in southeast Chongqing, China. Energy & Fuels 32, 6603-6618.Zhao, X., Zhou, L., Pu, X., Jin, F., Han, W., Xiao, D., Chen, S., Shi, Z., Zhang, W., Yang, F., 2018. Geological characteristics of shale rock system and shale oil exploration breakthrough in a lacustrine basin: A case study from the Paleogene 1st sub-member of Kong 2 Member in Cangdong sag, Bohai Bay Basin, China. Petroleum Exploration and Development 45, 377-388.Zou, J., Rezaee, R., Xie, Q., You, L., Liu, K., Saeedi, A., 2018. Investigation of moisture effect on methane adsorption capacity of shale samples. Fuel 232, 323-332.AbstractsAcevedo, S., Castillo, J., Vargas, V., Castro, A., Delgado, O., Cortés, F.B., Franco, C.A., Bouyssiere, B., 2018. Suppression of phase separation as a hypothesis to account for nuclei or nanoaggregate formation by asphaltenes in toluene. Energy & Fuels 32, 6669-6677., the concept of suppression of phase separation is proposed to account for the solubility behavior of asphaltenes at high dilution in toluene under ambient conditions. Nuclei formation at concentrations near 90 mg L–1 is the consequence of reaching A1 fraction solubility, and phase separation is suppressed by the intercalation of sufficient A2 in these nuclei or nanoaggregates. Presumably, such intercalation leads to media penetration of the nuclei periphery, hindering the growth and allowing for nuclei dispersion as a kinetic unit. Trapped compounds (TCs) or compounds trapped by asphaltene clusters were isolated, and their elemental analysis showed that they were neither resins nor asphaltenes. The information available regarding the A1 and A2 asphaltene subfractions is revised and complemented with new thermogravimetric analysis, simulation distillation (SimDis) curves, microcarbon Conradson, softening points, and nanoparticle results involving size-exclusion microchromatography. In general, physical results, such as solubility, SimDis, aggregation, and the softening point, differ substantially, whereas structural results, such as elemental analysis, DBE, and 13C nuclear magnetic resonance spectra, are similar. These results suggest that minor structural differences strongly affect the solubility, softening point, and other physical characteristics.Agrawal, V., Sharma, S., 2018. Testing utility of organogeochemical proxies to assess sources of organic matter, paleoredox conditions, and thermal maturity in mature Marcellus Shale. Frontiers in Energy Research 6, 42. doi: 10.3389/fenrg.2018.00042. is generally accepted that in mature shales, biomarkers and pyrolysis proxies are not very helpful in understanding the source/type of organic matter (OM), paleo-redox conditions during deposition and thermal maturity. The purpose of the study study was conducted to test the efficacy of these proxies in mature Marcellus shale (VRo> 1). Samples were collected from oil-prone (WV-7) and gas-prone (WV-6) wells in Wetzel and Monongalia Counties, West Virginia, respectively. These wells were chosen for this test study because high-resolution geochemical and isotopic studies have previously been conducted on these cores and depositional model had been proposed. The model suggests that sediments in WV-6 well are more mature, received higher terrestrial OM influx and were deposited in less anoxic environment as compared to WV-7 well. We used an improved method to extract the small amount of biomarkers preserved in the samples. Further, the extracts were analyzed by a high-resolution GC×GC FID method to quantify the distribution of aliphatic biomarkers. The hydrogen and oxygen indices (HI vs. OI plot) determined by Source Rock Analysis could not be used to determine the kerogen type due to their very low values. However, interpretations were derived from S1 vs. S2 and S2/S3 vs. TOC cross plots, thermal maturity parameter (Tmax), fraction conversion of OM to hydrocarbon (HC), and residual carbon/pyrolysable carbon (RC/PC) ratio. The conclusions drawn from the biomarkers and SRA data are in agreement with the HC production data from these wells as well as interpretations derived from geochemical and isotopic studies conducted on these core. Therefore, we propose that despite some limitations biomarker and pyrolysis proxies can be used to determine the thermal and depositional history of mature shales like the Marcellus Shale.Ahad, J.M.E., Pakdel, H., Gammon, P.R., Siddique, T., Kuznetsova, A., Savard, M.M., 2018. Evaluating in situ biodegradation of 13C-labelled naphthenic acids in groundwater near oil sands tailings ponds. Science of The Total Environment 643, 392-399. seepage of naphthenic acids (NAs) from tailings ponds into surface water and groundwater is one of the main environmental concerns associated with the Canadian Athabasca oil sands mining operations. Here we report the application of 13C-labelled NA surrogate compounds to evaluate intrinsic biodegradation along groundwater flow-paths originating from oil sands tailings ponds at two different sites: a glacio-fluvial aquifer (Site 1) and a low-lying wetland (Site 2). Microcosms containing the carboxyl group labelled (99%) NA surrogates (cyclohexanecarboxylic acid, CHCA; 1,2-cyclohexanedicarboxylic acid, CHDCA; 1-adamantanecarboxylic acid, ACA) were lowered into monitoring wells for several months to allow sufficient time for substrate degradation and formation of a biofilm in conditions characteristic of the local aquifer. Phospholipid fatty acids (PLFAs), biomarkers for the active microbial population, were extracted from the biofilms for stable carbon isotope (δ13C) analysis. At Site 1, highly 13C-enriched δ13C values (up to ~+7100‰) confirmed the in situ microbial breakdown of CHCA and CHDCA. At Site 2, δ13C-PLFA values from ?60.6 to ?24.5‰ indicated uptake of a 13C-depleted substrate such as biogenic methane and not 13C-labelled ACA. Determination of the microbial community using 16s RNA sequencing confirmed the presence of methane-oxidizing bacteria in the subsurface at Site 2. The in situ biodegradation of NAs at Site 1 demonstrates that the indigenous microbial population in the shallow subsurface near tailings ponds can readily break down some of these compounds prior to surface water discharge. The lack of evidence for microbial uptake of 13C-labelled ACA at Site 2 demonstrates that other NAs, in particular tricyclic diamondoid acids, may persist in the environment following seepage from tailings ponds or natural sources.Al-Ananzeh, N.M., Al-Smadi, M.L., Dawagreh, A.-K.M.A., 2018. Thermogravimetric and composition analysis of Jordanian oil shale. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 40, 1374-1379. occupies the eighth place in oil shale reserve in the world. Prospective efforts are directed toward the production of fuel from shale. Analysis of oil shale samples will help in planning for energy strategies. Oil shale samples were collected from Wadi Ash Shallala at Yarmouk Basin. X-ray fluorescence spectrometer and X-ray diffraction showed that calcite is the dominant mineral. Other minerals such as; Kaolinite, quartz, and Fluorapatite, were detected. Thermogravimetric analysis revealed that mass loss is due to organic matter decomposition at 350–550°C and carbonate and silicate decomposition at 650–850°C. Fourier transform infrared analysis revealed the main organic groups.Al-Kaabi, N., Al-Ghouti, M.A., Oualha, M., Mohammad, M.Y., Al-Naemi, A., S?lling, T.I., Al-Shamari, N., Zouari, N., 2018. A MALDI-TOF study of bio-remediation in highly weathered oil contaminated soils. Journal of Petroleum Science and Engineering 168, 569-576. have shown that Bacillus cereus is dominating the bacterial population at three polluted oil-industry sites where weather and soil conditions are extreme in terms of temperature, UV-radiation and salinity. A minor part of the bacterial population includes a strain of Bacillus sonorensis and Pseudomonas stuztzeri. Six bacterial isolates were characterized by MALDI-TOF mass spectrometry. The identity of Bacillus sonorensis was also confirmed by ribotyping using molecular techniques. The extreme conditions result in the limited bacterial diversity at the present sites. Our results indicate that the bacteria have sustained because of their ability to degrade low, medium and high molecular weight hydrocarbons in diesel which were removed by up to 89%, 61% and 92%, respectively by Bacillus sonorensis. Bacillus cereus isolates were less effective, but all showed high activity on high molecular weight hydrocarbons. The study is based on growth tolerance to high diesel toxicity and removal of the three ranges of hydrocarbons. Each isolate showed higher hydrocarbon removal efficiencies when applied separately in biopiles in fresh soil compared to weathered soil. Almost 88% and 25% of the diesel range organics and 23% and 83% of the polyaromatic hydrocarbons were removed from the weathered soil versus the clean, respectively, by Bacillus sonorensis. Such efficiencies were obtained with growth stimulation by addition of nitrogen and phosphorus sources and with Tween-80 as a surfactant. The results are key in an application context, since it is clear that overcoming the recalcitrance of weathered hydrocarbon contaminations to biodegradation is a central issue in for example the Arabian Gulf. Moreover the results emphasize that bioaugmentation/biostimulation with bacteria originally adapted to the site conditions is the way forward since endogenous or exogenous hydrocarbon-degrading bacteria generally are not appropriate for applications that involve weathered hydrocarbon spills.Al Obaidi, Y., Kozminski, M., Ward, J.D., 2018. Method and device for quantitative measurement of crude oil fouling deposits of several crude oils and blends at a higher temperature and the impact of antifoulant additives. Energy & Fuels 32, 6782-6787. the establishment of crude oil refining, refiners have encountered the problem of fouling in heat exchanger trains, heaters, and atmospheric and vacuum distillation columns. Crude oil fouling is one of the major problems that triggers efficiency reduction, environmental impact, unplanned shutdown, and loss of revenue and yield. In the topic of crude oil fouling, most published papers were focused on heat exchanger fouling and, to a lesser extent, the distillation columns and heaters. However, with the absence of a vacuum column, some small refineries operate and flash the crude oil at or above 700 °F for better recovery. In this study, a simple and affordable bench-type research laboratory rig was fabricated and used for the determination of the gravimetric fouling deposits for several crude oils and blends at an elevated temperature of 720 °F or more. To address the high-temperature impact on crude oil fouling, the ΔAPI and Δmicrocarbon were used to indicate the extent of the thermal cracking. Ultraviolet–visible spectroscopy was used to detect the increased aromaticity of agglomerated asphaltenes and resins as a result of the possible self-association at higher temperatures. At a higher temperature, the thermal cracking is much greater than that at 580–620 °F and the fouling could take on different mechanisms.Albers, C.N., Kramsh?j, M., Rinnan, R., 2018. Rapid mineralization of biogenic volatile organic compounds in temperate and Arctic soils. Biogeosciences 15, 3591-3601. volatile organic compounds (BVOCs) are produced by all life forms. Their release into the atmosphere is important with regards to a number of climate-related physical and chemical processes and great effort has been put into determining sources and sinks of these compounds in recent years. Soil microbes have been suggested as a possible sink for BVOCs in the atmosphere; however, experimental evidence for this sink is scarce despite its potentially high importance to both carbon cycling and atmospheric concentrations of these gases. We therefore conducted a study with a number of commonly occurring BVOCs labelled with 14C and modified existing methods to study the mineralization of these compounds to 14CO2 in four different topsoils. Five of the six BVOCs were rapidly mineralized by microbes in all soils. However, great differences were observed with regards to the speed of mineralization, extent of mineralization and variation between soil types. Methanol, benzaldehyde, acetophenone and the oxygenated monoterpene geraniol were mineralized within hours in all soils. The hydrocarbon monoterpene p-cymene was mineralized rapidly in soil from a coniferous forest but was mineralized slower in soil from an adjacent beech stand, while chloroform was mineralized slowly in all soils. From our study it is clear that soil microbes are able to completely degrade BVOCs released by above-ground vegetation as well as BVOCs released by soil microbes and plant roots. In addition to the possible atmospheric implications of this degradation, the very fast mineralization rates are likely important in shaping the net BVOC emissions from soil and it is possible that BVOC formation and degradation may be important but little-recognized parts of internal carbon cycling in soil.Alcalde, J., Flude, S., Wilkinson, M., Johnson, G., Edlmann, K., Bond, C.E., Scott, V., Gilfillan, S.M.V., Ogaya, X., Haszeldine, R.S., 2018. Estimating geological CO2 storage security to deliver on climate mitigation. Nature Communications 9, Article 2201. capture and storage (CCS) can help nations meet their Paris CO2 reduction commitments cost-effectively. However, lack of confidence in geologic CO2 storage security remains a barrier to CCS implementation. Here we present a numerical program that calculates CO2 storage security and leakage to the atmosphere over 10,000 years. This combines quantitative estimates of geological subsurface CO2 retention, and of surface CO2 leakage. We calculate that realistically well-regulated storage in regions with moderate well densities has a 50% probability that leakage remains below 0.0008% per year, with over 98% of the injected CO2 retained in the subsurface over 10,000 years. An unrealistic scenario, where CO2 storage is inadequately regulated, estimates that more than 78% will be retained over 10,000 years. Our modelling results suggest that geological storage of CO2 can be a secure climate change mitigation option, but we note that long-term behaviour of CO2 in the subsurface remains a key uncertainty.Ale-Agha, N., Goy, C., Jakobs, P., Spyridopoulos, I., Gonnissen, S., Dyballa-Rukes, N., Aufenvenne, K., von Ameln, F., Zurek, M., Spannbrucker, T., Eckermann, O., Jakob, S., Gorressen, S., Abrams, M., Grandoch, M., Fischer, J.W., K?hrer, K., Deenen, R., Unfried, K., Altschmied, J., Haendeler, J., 2018. CDKN1B/p27 is localized in mitochondria and improves respiration-dependent processes in the cardiovascular system—New mode of action for caffeine. PLOS Biology 16, Article e2004408.: We show that the cyclin-dependent kinase inhibitor 1B (CDKN1B)/p27, previously known as a cell cycle inhibitor, is also localized within mitochondria. The migratory capacity of endothelial cells, which need intact mitochondria, is completely dependent on mitochondrial p27. Mitochondrial p27 improves mitochondrial membrane potential, increases adenosine triphosphate (ATP) content, and is required for the promigratory effect of caffeine. Domain mapping of p27 revealed that the N-terminus and C-terminus are required for those improvements. Further analysis of those regions revealed that the translocation of p27 into the mitochondria and its promigratory activity depend on serine 10 and threonine 187. In addition, mitochondrial p27 protects cardiomyocytes against apoptosis. Moreover, mitochondrial p27 is necessary and sufficient for cardiac myofibroblast differentiation. In addition, p27 deficiency and aging decrease respiration in heart mitochondria. Caffeine does not increase respiration in p27-deficient animals, whereas aged mice display improvement after 10 days of caffeine in drinking water. Moreover, caffeine induces transcriptome changes in a p27-dependent manner, affecting mostly genes relevant for mitochondrial processes. Caffeine also reduces infarct size after myocardial infarction in prediabetic mice and increases mitochondrial p27. Our data characterize mitochondrial p27 as a common denominator that improves mitochondria-dependent processes and define an increase in mitochondrial p27 as a new mode of action of caffeine.Author summary: The protein p27 is a nuclear cell cycle inhibitor that can be shuttled to the cytoplasm to inactivate its inhibitory role, and this mechanism is thought to be used by cancer cells to unlock cell cycle arrest. Recent reports, however, have shown that p27 has other roles independent of cell cycle regulation, and it was observed that p27 mutant mice had increased mortality to myocardial infarction. Here, we have analyzed the potential role of p27 in the major cell types of the heart and shown that it is also present in mitochondria, the cellular powerhouses, where it fulfils important functions. We find that p27 is required for migration of endothelial cells by enhancing mitochondrial functions and that caffeine concentrations reached after consumption of 4 cups of coffee induce its translocation into mitochondria. Moreover, we observe that mitochondrial p27 protects heart muscle cells from cell death and is necessary for the conversion of fibroblasts into mechanically strong, contractile myofibroblasts, a process critical after myocardial infarction. Molecularly, we show that p27 is essential for caffeine-induced gene expression changes that mainly affect mitochondria and for mitochondrial respiration. We conclude that mitochondrial p27 improves mitochondria-dependent processes in heart cells and that physiological concentrations of caffeine have a protective effect.Alinoori, A.H., Masoum, S., 2018. Multicapillary gas chromatography—temperature modulated metal oxide semiconductor sensors array detector for monitoring of volatile organic compounds in closed atmosphere using Gaussian apodization factor analysis. Analytical Chemistry 90, 6635-6642. unique metal oxide semiconductor sensor (MOS) array detector with eight sensors was designed and fabricated in a PTFE chamber as an interface for coupling with multicapillary gas chromatography. This design consists of eight transfer lines with equal length between the multicapillary columns (MCC) and sensors. The deactivated capillary columns were passed through each transfer line and homemade flow splitter to distribute the same gas flow on each sensor. Using the eight ports flow splitter design helps us to equal the length of carrier gas path and flow for each sensor, minimizing the dead volume of the sensor’s chamber and increasing chromatographic resolution. In addition to coupling of MCC to MOS array detector and other considerations in hardware design, modulation of MOS temperature was used to increase sensitivity and selectivity, and data analysis was enhanced with adapted Gaussian apodization factor analysis (GAFA) as a multivariate curve resolution algorithm. Continues air sampling and injecting system (CASI) design provides a fast and easily applied method for continues injection of air sample with no additional sample preparation. The analysis cycle time required for each run is less than 300 s. The high sample load and sharp injection with the fast separation by MCC decrease the peak widths and improve detection limits. This homemade customized instrument is an alternative to other time-consuming and expensive technologies for continuous monitoring of outgassing in air samples.Alizadeh, B., Maroufi, K., Heidarifard, M.H., 2018. Estimating source rock parameters using wireline data: An example from Dezful Embayment, South West of Iran. Journal of Petroleum Science and Engineering 167, 857-868. and high potential of wireline data to correlate with geochemical properties convinced petroleum geologists to use them for source rock detection and calculating their richness. In this research, intelligent techniques and mathematical relationships were used to evaluate source rock potential and organic matter type indirectly. Artificial neural networks (ANN) and ΔLogR techniques were successfully used to model the relation between wireline logs and Total Organic Carbon (TOC) content. Furthermore, wireline data and TOC values were used as input data to model a second ANN for S2 parameter (present hydrocarbon potential) calculation. Owing to its great ability in the course of solving non-linear problems with overwhelming complexity, the back propagation method was used to train the networks using 70 points datasets. Predicted TOC contents were validated by Rock-Eval pyrolysis results of which revealed dependency of the ΔLogR accuracy to the organic richness and lithology, and therefore higher precision of the ANN outputs in compare to the ΔLogR results.Hydrogen Index (HI) and kerogen type were also effectively predicted using mathematical relationship between TOC and S2 factors. Reliability of all steps of the methodology was approved using a 16 members retest dataset for which testing predicted parameters against measured data demonstrated good correlation coefficients combined with negligible errors. Finally, applicability of the methodology was checked by applying it on two wells in the Dezful Embayment to evaluate geochemical and depositional properties of the Paleocene-Early Oligocene Pabdeh Formation.Alnarabiji, M.S., Yahya, N., Nadeem, S., Adil, M., Baig, M.K., Ghanem, O.B., Azizi, K., Ahmed, S., Maulianda, B., Kleme?, J.J., Elraies, K.A., 2018. Nanofluid enhanced oil recovery using induced ZnO nanocrystals by electromagnetic energy: Viscosity increment. Fuel 233, 632-643. the trapped oil in the pores and channels of rock reservoirs, after secondary recovery, using traditional enhanced oil recovery (EOR) techniques is still a challenging task. Nano-materials offer novel pathways to address these unsolved challenges as EOR agents due to their unique characteristics. This study aimed to investigate the novel use of zinc oxide nanocrystals (ZnO-NCs) in EOR and, investigate the influence of the combination of ZnO-NCs with EM energy irradiation on the recovery efficiency. For this purpose, different nanofluid concentrations and flow rates, as well as brine salinity was injected into the porous medium, in the absence of EM energy, to obtain the optimum experimental conditions with the highest recovery efficiency. The injected nanofluid in the porous medium, under the optimum conditions, was subjected to EM energy. The Zinc oxide nanofluid (ZnO-NF) showed a significant rise in recovery efficiency in the absence of EM energy by 50% ROIP due to the self-assembling of the ZnO-NCs which resulted in an increment in the local viscosity of the nanofluid at the water–oil interface. This study proved the capability of EM energy to enhance the viscosity of the injected ZnO-NF in the porous medium, which consequently increased the recovery efficiency by 23.3% ROIP through the electrorheological effect of the activated dielectric ZnO-NCs.Amenabar, M.J., Boyd, E.S., 2018. Mechanisms of mineral substrate acquisition in a thermoacidophile. Applied and Environmental Microbiology 84, Article e00334-00318.: The thermoacidophile Acidianus is widely distributed in Yellowstone National Park hot springs that span large gradients in pH (1.60 to 4.84), temperature (42 to 90°C), and mineralogical composition. To characterize the potential role of flexibility in mineral-dependent energy metabolism in contributing to the widespread ecological distribution of this organism, we characterized the spectrum of minerals capable of supporting metabolism and the mechanisms that it uses to access these minerals. The energy metabolism of Acidianus strain DS80 was supported by elemental sulfur (S0), a variety of iron (hydr)oxides, and arsenic sulfide. Strain DS80 reduced, oxidized, and disproportionated S0. Cells growing via S0 reduction and disproportionation did not require direct access to the mineral to reduce it, whereas cells growing via S0 oxidation did require direct access, observations that are attributable to the role of H2S produced by S0 reduction/disproportionation in solubilizing and increasing the bioavailability of S0. Cells growing via iron (hydr)oxide reduction did not require access to the mineral, suggesting that the cells reduce Fe(III) that is being leached by the acidic growth medium. Cells growing via oxidation of arsenic sulfide with Fe(III) did not require access to the mineral to grow. The stoichiometry of reactants to products indicates that cells oxidize soluble As(III) released from oxidation of arsenic sulfide by aqueous Fe(III). Taken together, these observations underscore the importance of feedbacks between abiotic and biotic reactions in influencing the bioavailability of mineral substrates and defining ecological niches capable of supporting microbial metabolism. Importance: Mineral sources of electron donor and acceptor that support microbial metabolism are abundant in the natural environment. However, the spectrum of minerals capable of supporting a given microbial strain and the mechanisms that are used to access these minerals in support of microbial energy metabolism are often unknown, in particular among thermoacidophiles. Here, we show that the thermoacidophile Acidianus strain DS80 is adapted to use a variety of iron (hydro)oxide minerals, elemental sulfur, and arsenic sulfide to support growth. Cells rely on a complex interplay of abiologically and biologically catalyzed reactions that increase the solubility or bioavailability of minerals, thereby enabling their use in microbial metabolism. Amo-González, M., Carnicero, I., Pérez, S., Delgado, R., Eiceman, G.A., Fernández de la Mora, G., Fernández de la Mora, J., 2018. Ion mobility spectrometer-fragmenter-ion mobility spectrometer analogue of a triple quadrupole for high-resolution ion analysis at atmospheric pressure. Analytical Chemistry 90, 6885-6892. differential mobility analyzers (DMAs) acting as narrow band mobility filters are coupled in series, with a thermal fragmentation cell placed in between, such that parent ions selected in DMA1 are fragmented in the cell at atmospheric pressure, and their product ions are analyzed on DMA2. Additional mass spectrometer analysis is performed for ion identification purposes. A key feature of the tandem DMA is the short residence time (～0.2 ms) of ions in the analyzer, compared to tens of milliseconds in drift tube ion mobility spectrometers (IMS). Ion fragmentation within the analyzer and associated mobility tails are therefore negligible for a DMA but not necessarily so in conventional IMS. This advantage of the DMA is demonstrated here by sharply defined product ion mobility peaks. Ambient pressure ion fragmentation has been previously demonstrated by both purely thermal means as well as rapidly oscillating intense electric fields. Our purely thermal fragmentation cell here achieves temperatures up to 700 °C measured inside the heating coil of a cylindrical ceramic heater, through whose somewhat colder axis we direct a beam of mobility-selected ions. We investigate tandem separation of chloride adducts from the explosives EGDN, nitroglycerine (NG), PETN, and RDX and from deprotonated TNT. Atmospheric pressure fragmentation of the first three ions yields one or several previously reported fragments, providing highly distinctive tandem DMA channels for explosive identification at 1 atm. RDX ions had not been previously fragmented at ambient pressure, yet [RDX + Cl]– converts up to 7% (at 300 °C) into a 166 m/z product. The known high thermal resilience of TNT is confirmed here by its rather modest conversion, even when the ceramic is heated to 700 °C. At this temperature some previously reported fragments are found, but their mobilities are fairly close to each other and to the one of the far more abundant parent ion, making their identification by mobility alone problematic. We anticipate that moderately higher fragmenter temperatures will produce smaller fragments with mobilities readily separated from that of [TNT – H]–.Anantharaman, K., Hausmann, B., Jungbluth, S.P., Kantor, R.S., Lavy, A., Warren, L.A., Rappé, M.S., Pester, M., Loy, A., Thomas, B.C., Banfield, J.F., 2018. Expanded diversity of microbial groups that shape the dissimilatory sulfur cycle. The ISME Journal 12, 1715-1728. critical step in the biogeochemical cycle of sulfur on Earth is microbial sulfate reduction, yet organisms from relatively few lineages have been implicated in this process. Previous studies using functional marker genes have detected abundant, novel dissimilatory sulfite reductases (DsrAB) that could confer the capacity for microbial sulfite/sulfate reduction but were not affiliated with known organisms. Thus, the identity of a significant fraction of sulfate/sulfite-reducing microbes has remained elusive. Here we report the discovery of the capacity for sulfate/sulfite reduction in the genomes of organisms from 13 bacterial and archaeal phyla, thereby more than doubling the number of microbial phyla associated with this process. Eight of the 13 newly identified groups are candidate phyla that lack isolated representatives, a finding only possible given genomes from metagenomes. Organisms from Verrucomicrobia and two candidate phyla, Candidatus Rokubacteria and Candidatus Hydrothermarchaeota, contain some of the earliest evolved dsrAB genes. The capacity for sulfite reduction has been laterally transferred in multiple events within some phyla, and a key gene potentially capable of modulating sulfur metabolism in associated cells has been acquired by putatively symbiotic bacteria. We conclude that current functional predictions based on phylogeny significantly underestimate the extent of sulfate/sulfite reduction across Earth’s ecosystems. Understanding the prevalence of this capacity is integral to interpreting the carbon cycle because sulfate reduction is often coupled to turnover of buried organic carbon. Our findings expand the diversity of microbial groups associated with sulfur transformations in the environment and motivate revision of biogeochemical process models based on microbial community composition.Anderson, J.S., Romanak, K.D., Meckel, T.A., 2018. Assessment of shallow subsea hydrocarbons as a proxy for leakage at offshore geologic CO2 storage sites. International Journal of Greenhouse Gas Control 74, 19-27. study is part of a multi-phase effort to identify and characterize offshore geological carbon storage (GCS) potential along the Texas Gulf Coast. Previous efforts acquired a high-resolution 3D seismic dataset (P-cable?) and interpreted a seismically discontinuous zone as shallow gas pockets (<100?m below seafloor) associated with a vertical chimney structure. Our approach was to measure hydrocarbon concentrations and stable carbon isotopes near the seafloor to assess if gas migrated vertically from seismic anomalies. Deep-sourced thermogenic hydrocarbons would indicate that the structure is transmissive which could indicate an unacceptable risk for GCS at the site. Alternatively, hydrocarbons formed in-situ from biogenic processes would not preclude transmissivity of the structure but would add information to the risk assessment. Gases were extracted from 23 piston core samples recovered between 2.56 and 3.50?m subseafloor. Light hydrocarbons and stable carbon isotopes of methane were used for source attribution. The result was that geochemical signatures were consistent with typical background values observed within the first few meters of subsea sediment and therefore did not indicate leakage from depth. From our analysis, we offer insights into the use of hydrocarbon molecular and isotopic compositions at the seafloor for signal attribution as part of environmental assessments at geological CO2 storage sites.Andrae, J.W., McInerney, F.A., Polissar, P.J., Sniderman, J.M.K., Howard, S., Hall, P.A., Phelps, S.R., 2018. Initial expansion of C4 vegetation in Australia during the Late Pliocene. Geophysical Research Letters 45, 4831-4840. Since the late Miocene, plants using the C4 photosynthetic pathway have increased to become major components of many tropical and subtropical ecosystems. However, the drivers for this expansion remain under debate, in part because of the varied histories of C4 vegetation on different continents. Australia hosts the highest dominance of C4 vegetation of all continents, but little is known about the history of C4 vegetation there. Carbon isotope ratios of plant waxes from scientific ocean drilling sediments off north?western Australia reveal the onset of Australian C4 expansion at ~3.5?Ma, later than in many other regions. Pollen analysis from the same sediments reveals increasingly open C3-dominated biomes preceding the shift to open C4-dominated biomes by several million years. We hypothesize that the development of a summer monsoon climate beginning in the late Pliocene promoted a highly seasonal precipitation regime favorable to the expansion of C4 vegetation.Plain Language Summary. This study documents for the first time that C4 vegetation initially expanded on the Australian continent in the late Pliocene, several million years later than in Asia, Africa, North America, and South America. The expansion of C4 plants displaced C3 open habitat vegetation. Understanding the timing and sequence of expansion of C4‐dominated biomes enables us to better constrain the key environmental and evolutionary factors in their development and provides a basis for future conservation of these widespread and important biomes. Ansah, E.O., Sugai, Y., Sasaki, K., 2018. Modeling microbial-induced oil viscosity reduction: Effect of temperature, salinity and nutrient concentration. Petroleum Science and Technology 36, 1113-1119. research simulated oil recovery with emphasis on oil viscosity reduction by direct microbe action and metabolites; predicted hydrogeochemical reactions involved with nutrient ? brine interaction in reservoirs. PHREEQC was used to simulate reactions between the reservoir brine and nutrient minus microbe. Hitherto, UTCHEM was employed for the enhancement of oil viscosity by assuming production of gases and by the direct microbe action. The model depicted the precipitation of calcite plus dissolution of k-feldspar combined with the evolution of CO2 and CH4 influenced by temperature and pH. Oil recovery was directly proportional to salinity reduction and increasing nutrient concentration.Aoki, S., Kabashima, C., Kato, Y., Hirata, T., Komiya, T., 2018. Influence of contamination on banded iron formations in the Isua supracrustal belt, West Greenland: Reevaluation of the Eoarchean seawater compositions. Geoscience Frontiers 9, 1049-1072. Iron Formations (BIFs) are chemical sediments, ubiquitously distributed in the Precambrian supracrustal belts; thus their trace element compositions are helpful for deciphering geochemical evolution on the Earth through time. However, it is necessary to elucidate factors controlling the whole-rock compositions in order to decode the ancient seawater compositions because their compositions are highly variable. We analyzed major and trace element contents of the BIFs in the 3.8–3.7?Ga Isua supracrustal belt (ISB), southern West Greenland. The BIFs are petrographically classified into four types: Black-, Gray-, Green- and White-types, respectively. The Green-type BIFs contain more amphiboles, and are significantly enriched in Co, Ni, Cu, Zn, Y, heavy rare earth element (HREE) and U contents. However, their bulk compositions are not suitable for estimate of seawater composition because the enrichment was caused by secondary mobility of metamorphic Mg, Ca and Si-rich fluid, involvement of carbonate minerals and silicate minerals of olivine and pyroxene and/or later silicification or contamination of volcanic and clastic materials. The White-type BIFs are predominant in quartz, and have lower transition element and REE contents. The Gray-type BIFs contain both quartz and magnetite. The Black-type BIFs are dominated by magnetite, and contain moderate to high transition element and REE contents. But, positive correlations of V, Ni, Zn and U contents with Zr contents suggest that involvement of detrital, volcanic and exhalative materials influences on their contents. The evidence for significant influence of the materials on the transition element contents such as Ni in the BIFs indicates the transition element contents in the Archean ocean were much lower than previously estimated. We reconstructed secular variations of V, Co, Zn and U contents of BIFs through time, which show Ni and Co contents decreased whereas V, Zn and U contents increased through time. Especially, the Ni and Co contents drastically decreased in the Mesoarchean rather than around the Great Oxidation Event. On the other hand, the V, Zn and U contents progressively increased from the Mesoarchean to the Proterozoic. Stratigraphical trends of the BIFs show increase in Y/Ho ratios and decrease in positive Eu anomaly upwards, respectively. The stratigraphic changes indicate that a ratio of hydrothermal fluid to seawater component gradually decrease through the deposition, and support the Eoarchean plate tectonics, analogous to the their stratigraphic variations of seafloor metalliferous sediments at present and in the Mesoarchean.Aristov, A., Lelandais, B., Rensen, E., Zimmer, C., 2018. ZOLA-3D allows flexible 3D localization microscopy over an adjustable axial range. Nature Communications 9, Article 2409. molecule localization microscopy can generate 3D super-resolution images without scanning by leveraging the axial variations of normal or engineered point spread functions?(PSF). Successful implementation of these approaches for extended axial ranges remains, however, challenging. We present Zernike Optimized Localization Approach in 3D?(ZOLA-3D), an easy-to-use computational and optical solution that achieves optimal resolution over a tunable axial range. We use ZOLA-3D to demonstrate 3D super-resolution imaging of mitochondria, nuclear pores and microtubules in entire nuclei or cells up to ~5?μm deep.Ariza, E., Chaves-Guerrero, A., Molina V, D., 2018. Effect of average molecular parameters of asphaltenes on the rheological properties of crude oils from Colorado oil field. Energy & Fuels 32, 6557-6564. our previous articles (Energy & Fuels 2017, 31, 133–139 and Energy & Fuels 2017, 31, 8997–9005), it was presented that the asphaltenes of the Colorado field have different chemical structures, and these change the properties of crystallization of the paraffins. In this paper, we present a new way to understand the effects of the chemical structure of the asphaltenes on crude oil rheology, which includes correlating the average molecular parameters (AMPs) and the concentration of the asphaltenes with rheological properties using chemometric methods such as the partial least squares method. The asphaltenes were separated from six crude oil samples (average °API of 38) and were characterized using nuclear magnetic resonance to determine their main molecular parameters. Rheological properties including viscosity, yield stress, and gel temperature were experimentally determined for each of the crude oil samples and their respective maltenes. The results of a multivariate analysis show that the AMPs of the asphaltenes that cause the greatest effects are the ratio of peripheral aromatic carbons to aromatic carbons (Cp/Car) and pericondensed aromatic carbons (Caaa), which increase the gel temperature among maltenes and crude oils. The concentration of the asphaltenes (Coasf) contributes to decreasing this property. An increase in the yield stress is mainly caused by the aliphatic chains of the asphaltenes (n) and the molecular weight (Mw), whereas Coasf causes decrease on the yield stress. Finally, the change in viscosity at 20 °C is increased by Cp/Car and is decreased by Coasf and paraffinic carbons (Cs).Ashish, Debnath, M., 2018. Application of biosurfactant produced by an adaptive strain of C. tropicalis MTCC230 in microbial enhanced oil recovery (MEOR) and removal of motor oil from contaminated sand and water. Journal of Petroleum Science and Engineering 170, 40-48. enhanced oil recovery (MEOR) represents the use of microorganisms or their products to recover remaining oil trapped up in oil reservoirs. In this study adaptive strain C. tropicalis MTCC230 was used to determine its suitability in MEOR. Biosurfactant produced from an adaptive strain C. tropicalis MTCC230 was characterized as lipopeptide surfactin by Near IR, FTIR spectrum and HPLC and mass spectroscopy analysis. It can significantly reduce the surface tension 72?mN/m to 32?mN/m, with the critical micelle concentration (CMC) of 32.5?mg/l and B. subtilis MTCC2423 used as a standard surfactin (Biosurfactant) producing strain for comparative study. It shows stable Physiochemical properties under the extreme pH (2–12), temperature (30°C-90?°C) and salinity (2%–10%) that promote its potential use in enhanced oil recovery. Oil spreading method and soil washing analysis confirmed it suitability to remove the hydrocarbon contaminants from water and soil. Laboratory scale sand pack column saturated with four stroke engine oil resulted ～39.80% additional oil recovery (AOR), suggesting its suitability for commercial use in microbial enhanced oil recovery (MEOR) in oil reservoirs.Ayuso-Fernández, I., Ruiz-Due?as, F.J., Martínez, A.T., 2018. Evolutionary convergence in lignin-degrading enzymes. Proceedings of the National Academy of Sciences 115, 6428-6433.: We analyze the molecular mechanisms that led to the rise of a powerful strategy for lignin degradation (i.e., the formation of a solvent-exposed tryptophanyl radical capable of oxidizing the bulky lignin polymer) as a convergent trait in different species of fungi (order Polyporales). We use ancestral sequence reconstruction and enzyme resurrection to obtain the ancestors of the two extant types of ligninolytic peroxidases—lignin peroxidase (LiP) and versatile peroxidase (VP)—and compare their predicted molecular structures and catalytic properties after resurrection. The results presented demonstrate convergent evolution in distant LiP and VP lineages with the exposed tryptophan residue appearing twice, as two independent events, following different molecular changes.Abstract: We analyze the molecular mechanisms that led to the rise of a powerful strategy for lignin degradation (i.e., the formation of a solvent-exposed tryptophanyl radical capable of oxidizing the bulky lignin polymer) as a convergent trait in different species of fungi (order Polyporales). We use ancestral sequence reconstruction and enzyme resurrection to obtain the ancestors of the two extant types of ligninolytic peroxidases—lignin peroxidase (LiP) and versatile peroxidase (VP)—and compare their predicted molecular structures and catalytic properties after resurrection. The results presented demonstrate convergent evolution in distant LiP and VP lineages with the exposed tryptophan residue appearing twice, as two independent events, following different molecular changes.The resurrection of ancestral enzymes of now-extinct organisms (paleogenetics) is a developing field that allows the study of evolutionary hypotheses otherwise impossible to be tested. In the present study, we target fungal peroxidases that play a key role in lignin degradation, an essential process in the carbon cycle and often a limiting step in biobased industries. Ligninolytic peroxidases are secreted by wood-rotting fungi, the origin of which was recently established in the Carboniferous period associated with the appearance of these enzymes. These first peroxidases were not able to degrade lignin directly and used diffusible metal cations to attack its phenolic moiety. The phylogenetic analysis of the peroxidases of Polyporales, the order in which most extant wood-rotting fungi are included, suggests that later in evolution these enzymes would have acquired the ability to degrade nonphenolic lignin using a tryptophanyl radical interacting with the bulky polymer at the surface of the enzyme. Here, we track this powerful strategy for lignin degradation as a phenotypic trait in fungi and show that it is not an isolated event in the evolution of Polyporales. Using ancestral enzyme resurrection, we study the molecular changes that led to the appearance of the same surface oxidation site in two distant peroxidase lineages. By characterization of the resurrected enzymes, we demonstrate convergent evolution at the amino acid level during the evolution of these fungi and track the different changes leading to phylogenetically distant ligninolytic peroxidases from ancestors lacking the ability to degrade nonphenolic lignin.Azzolina, N.A., Bosshart, N.W., Burton-Kelly, M.E., Hamling, J.A., Peck, W.D., 2018. Statistical analysis of pulsed-neutron well logs in monitoring injected carbon dioxide. International Journal of Greenhouse Gas Control 75, 125-133. well logs (PNLs) were acquired to monitor CO2 storage associated with enhanced oil recovery. This work quantifies the precision of repeat PNLs using data from four wells and 15 repeat PNLs. Root-mean-square (RMS) precision for the repeat PNLs was less than 3%, indicating good agreement between the baseline and repeat PNLs. Evaluations of scaled relative difference (Scaled-D) showed variation in precision among individual wells and formations. Analysis of false-positive rates (FPRs) across the entire data set showed that a Scaled-D threshold in sandstone formations of approximately ±8% resulted in a 1% FPR. These Scaled-D precision thresholds were used to estimate the value of CO2 saturation able to be confidently distinguished from baseline. The detection limit for CO2 is lowest for high-porosity formations filled with saline water and is highest for low-porosity formations filled with fresh water. Thus, detection of vertical out-of-zone CO2 migration using repeat PNLs is a function of instrument precision, petrophysical properties, and hydrology, all of which must be taken into account as part of the monitoring program. The results of this work provide insight into how PNLs may be included within monitoring plans to detect vertical out-of-zone CO2 migration along a wellbore or instances of wellbore failure and provide a quantitative basis for establishing detection limits of repeat PNLs to distinguish change from baseline conditions.Babilonia, J., Conesa, A., Casaburi, G., Pereira, C., Louyakis, A.S., Reid, R.P., Foster, J.S., 2018. Comparative metagenomics provides insight into the ecosystem functioning of the Shark Bay stromatolites, Western Australia. Frontiers in Microbiology 9, 1359. doi: 1310.3389/fmicb.2018.01359. are organosedimentary build-ups that have formed as a result of the sediment trapping, binding and precipitating activities of microbes. Today, extant systems provide an ideal platform for understanding the structure, composition, and interactions between stromatolite-forming microbial communities and their respective environments. In this study, we compared the metagenomes of three prevalent stromatolite-forming microbial mat types in the Spaven Province of Hamelin Pool, Shark Bay located in Western Australia. These stromatolite-forming mat types included an intertidal pustular mat as well as a smooth and colloform mat types located in the subtidal zone. Additionally, the metagenomes of an adjacent, non-lithifying mat located in the upper intertidal zone were also sequenced for comparative purposes. Taxonomic and functional gene analyses revealed distinctive differences between the lithifying and non-lithifying mat types, which strongly correlated with water depth. Three distinct populations emerged including the upper intertidal non-lithifying mats, the intertidal pustular mats associated with unlaminated carbonate build-ups, and the subtidal colloform and smooth mat types associated with laminated structures. Functional analysis of metagenomes revealed that amongst stromatolite-forming mats there was an enrichment of photosynthesis pathways in the pustular stromatolite-forming mats. In the colloform and smooth stromatolite-forming mats, however, there was an increase in the abundance of genes associated with those heterotrophic metabolisms typically associated with carbonate mineralization, such as sulfate reduction. The comparative metagenomic analyses suggest that stromatolites of Hamelin Pool may form by two distinctive processes that are highly dependent on water depth. These results provide key insight into the potential adaptive strategies and synergistic interactions between microbes and their environments that may lead to stromatolite formation and accretion.Bae, H.-S., Huang, L., White, J.R., Wang, J., DeLaune, R.D., Ogram, A., 2018. Response of microbial populations regulating nutrient biogeochemical cycles to oiling of coastal saltmarshes from the Deepwater Horizon oil spill. Environmental Pollution 241, 136-147. communities play vital roles in the biogeochemistry of nutrients in coastal saltmarshes, ultimately controlling water quality, nutrient cycling, and detoxification. We determined the structure of microbial populations inhabiting coastal saltmarsh sediments from northern Barataria Bay, Louisiana, USA to gain insight into impacts on the biogeochemical cycles affected by Macondo oil from the 2010 Deepwater Horizon well blowout two years after the accident. Quantitative PCR directed toward specific functional genes revealed that oiled marshes were greatly diminished in the population sizes of diazotrophs, denitrifiers, nitrate-reducers to ammonia, methanogens, sulfate-reducers and anaerobic aromatic degraders, and harbored elevated numbers of alkane-degraders. Illumina 16S rRNA gene sequencing indicated that oiling greatly changed the structure of the microbial communities, including significant decreases in diversity. Oil-driven changes were also demonstrated in the structure of two functional populations, denitrifying and sulfate reducing prokaryotes, using nirS and dsrB as biomarkers, respectively. Collectively, the results from 16S rRNA and functional genes indicated that oiling not only markedly altered the microbial community structures, but also the sizes and structures of populations involved in (or regulating) a number of important nutrient biogeochemical cycles in the saltmarshes. Alterations such as these are associated with potential deterioration of ecological services, and further studies are necessary to assess the trajectory of recovery of microbial-mediated ecosystem functions over time in oiled saltmarsh sediment.Bai, B., Wu, H., Li, X., 2018. Investigation on the relationship between wellhead injection pressure and injection rate for practical injection control in CO2 geological storage projects. Geofluids 2018, Article 4927415. existing investigations on the maximum allowable wellhead injection pressure have found the upper limit of wellhead injection pressure, which, however, cannot provide a practical operational designing scheme of wellhead injection parameters for CO2 geological storage projects. Therefore, this work firstly proposes the complete constraint conditions of wellbore injection to realize the whole process of forward and inverse calculations of wellbore pressure and then applies it to explore the relationship between wellhead injection pressure and injection rate. The results show that the wellhead injection pressure and the injection rate are a pair of mutually constrained physical quantities. For a certain injection project, the allowable wellhead injection pressure and injection rate separately form a continuous interval. Change of one quantity within its allowable interval will also change the other within its interval, both jointly forming a closed region. Thus, controlling the wellhead injection parameters in this closed region can simultaneously ensure the effectiveness and safety of injection. Subsequently, this work further studies the factors of impacting the relationship between wellhead injection pressure and injection rate and finds that all the temperature of injected fluid, the parameters of saturation, and the characteristic parameters of reservoirs only change their upper and lower limits to some extent but have no essential effects on their relationship. Application of this theory and method in Shenhua CCS demonstration project obtained the relationship diagram of wellhead injection pressure and injection rate, which found that its actual injection parameters just fall into the closed region of the relationship diagram, effectively verifying the reliability of this work.Bajtai, A., Lajkó, G., Szatmári, I., Fül?p, F., Lindner, W., Ilisz, I., Péter, A., 2018. Dedicated comparisons of diverse polysaccharide- and zwitterionic Cinchona alkaloid-based chiral stationary phases probed with basic and ampholytic indole analogs in liquid and subcritical fluid chromatography mode. Journal of Chromatography A 1563, 180-190. phase (NP) high-performance liquid and sub- and supercritical fluid chromatographic (both acronymed as SFC) methods have been developed for the enantiomer separation of three basic and three ampholytic structurally related C-3-substituted indole analogs on seven non-ionic (neutral) polysaccharide-based and two chemically entirely different zwitterionic Cinchona alkaloid- and sulfonic acid-based chiral stationary phases (CSPs). In a systematic fashion the effect of the composition of the mobile phase, the nature of the alcohol and amine additives on the retention characteristics and enantioselectivity of the ionizable analytes were investigated. On all studied polysaccharide-based CSPs the three ampholytes remained unretained in NP-LC mode, while they were nicely retained and resolved in SFC mode. These unexpected results underline a specific property of liquid CO2 as bulk solvent in combination with alcohols as co-solvents and amine additives thus creating an environment around the chiral selector sites which support the retention of ampholytes. The zwitterionic CSPs worked equally well for the resolution of the basic and ampholytic analytes using a polar ionic mobile phase in both LC and SFC modes.Results acquired by studying the effect of temperature were used to calculate the changes in standard enthalpy Δ(ΔH°), entropy Δ(ΔS°), and free energy Δ(ΔG°) applying van't Hoff plots. The values of the thermodynamic parameters depended on the nature of selectors, the structure of analytes and the properties of the mobile phases. On polysaccharide-based CSPs and columns operated in NP-LC mode enthalpically-, whereas in SFC mode both enthalpically- and entropically-driven enantiomer separations were observed.Bakermans, C., 2018. Adaptations to marine versus terrestrial low temperature environments as revealed by comparative genomic analyses of the genus Psychrobacter. FEMS Microbiology Ecology 94, Article fiy102. cold-adapted bacteria isolated from marine or terrestrial low temperature environments share many similarities, cold-adapted bacteria from terrestrial environments usually grow over a broader range of temperatures suggesting different constraints of these two low temperature environments. The diversity of habitats from which Psychrobacter have been isolated (e.g. cold marine environments, frozen soils, permafrost and humans) provides a unique opportunity to examine habitat specific adaptations while reducing phylogenetic effects. Here, comparative genomic analyses of 26 strains of Psychrobacter revealed several clusters with characteristics that correlated with habitat. Marine and terrestrial Psychrobacter have amino acid composition typical of psychrophiles (e.g. fewer proline and lysine, more acidic) when compared to Psychrobacter strains associated with warm hosts, and have many potentially cold-adapted core genes (e.g. ClpX, DsbC, GroEL/GroES and MutS2). Marine and terrestrial Psychrobacter share many genes (e.g. FadB) not found in warm host Psychrobacter, which had their own distinct gene content (e.g. collagenase-like protease). Furthermore, terrestrial Psychrobacter were differentiated from marine Psychrobacter by the use of different cold adaptations and more hydrophobic and aliphatic proteins. These data suggest that terrestrial and marine Psychrobacter evolved from a mesophilic ancestor and are accumulating adaptations for low temperatures as well as for their respective habitats.Bakkour, R., Bolotin, J., Sellergren, B., Hofstetter, T.B., 2018. Molecularly imprinted polymers for compound-specific isotope analysis of polar organic micropollutants in aquatic environments. Analytical Chemistry 90, 7292-7301. isotope analysis (CSIA) of polar organic micropollutants in environmental waters requires a processing of large sample volumes to obtain the required analyte masses for analysis by gas chromatography/isotope-ratio mass spectrometry (GC/IRMS). However, the accumulation of organic matter of unknown isotopic composition in standard enrichment procedures currently compromises the accurate determination of isotope ratios. We explored the use of molecularly imprinted polymers (MIPs) for selective analyte enrichment for 13C/12C and 15N/14N ratio measurements by GC/IRMS using 1H-benzotriazole, a typical corrosion inhibitor in dishwashing detergents, as example of a widely detected polar organic micropollutant. We developed procedures for the treatment of >10 L of water samples, in which custom-made MIPs enabled the selective cleanup of enriched analytes in organic solvents obtained through conventional solid-phase extractions. Hydrogen bonding interactions between the triazole moiety of 1H-benzotriazole, and the MIP were responsible for selective interactions through an assessment of interaction enthalpies and 15N isotope effects. The procedure was applied successfully without causing isotope fractionation to river water samples, as well as in- and effluents of wastewater treatment plants containing μg/L concentrations of 1H-benzotriazole and dissolved organic carbon (DOC) loads of up to 28 mg C/L. MIP-based treatments offer new perspectives for CSIA of organic micropollutants through the reduction of the DOC-to-micropollutant ratios.Balci, N., Demirel, C., Akcer ?n, S., Gültekin, A.H., Kurt, M.A., 2018. Evaluating abiotic and microbial factors on carbonate precipitation in Lake Acig?l, a hypersaline lake in Southwestern Turkey. Quaternary International 486, 116-128. recent carbonate precipitation occurs in Lake Ac?g?l, a hypersaline playa lake. Elucidating precipitation mechanisms of carbonate minerals under particularly supersaturated ionic solution at low temperature may hold key understanding to recognize microbial fingerprints throughout the Earth history. In the presented study abiotic and microbial factors controlling carbonate precipitation mechanisms are investigated by using geochemical, isotopic and chemical approaches. Our data demonstrated that aragonite, calcite and dolomite are readily precipitated in oxic column of lake water in decreasing order. Major metabolites profile of pore water showed that carbonate alkalinity and pH increased by microbial activity seems to be insignificant in the lake sediments to support precipitation. On the contrary a positive correlation between δ13C and δ18O values of carbonates suggest that carbonate super-saturation occurs as a result of evaporation and associated degassing of CO2 in the lake basin. However, a putative microbial role such as binding of cations to microbial cell wall or EPS to overcome kinetic inhibitors (e.g Mg2+) is likely possible in the lake as a driving carbonate precipitation mechanism. Overall, the present study demonstrated that carbonate precipitation in the lake is the result of complex players, such as lake water chemistry, ionic interactions, evaporation and EPS-organic compounds (e.g EPS) in addition to kinetic microbial processes. The data also provide a fundamental insight which is that revealing of changes in carbonate mineralogy of the lake, strongly influenced by evaporation, would provide significant insights about paleoclimatic conditions of the region.Banerjee, S., Hascakir, B., 2018. Flow control devices in SAGD completion design: Enhanced heavy oil/ bitumen recovery through improved thermal efficiency. Journal of Petroleum Science and Engineering 169, 297-308. method of thermal recovery, steam-assisted gravity drainage (SAGD), has proven a commercial success in heavy oil/bitumen production. However, geological and reservoir heterogeneity often complicate this task resulting in uneven production rates, higher operational costs, and stranded heavy oil/bitumen. This work theorizes that SAGD recovery is improved using flow control devices (FCDs) to force conformance in SAGD laterals. To test this theory, a novel protocol and test flow loop was developed to measure pressure drop across an autonomous hybrid FCD while flowing multiphase mixtures containing steam. This laboratory data was used to qualify existing pressure drop correlations and determine if nitrogen gas, a common test gas to describe FCD pressure drop response, creates suitable data for modeling steam systems. Finally, the flow loop was used to induce a steam “flash”, a transition of water at saturation temperature to vapor due to a suddenly decreased pressure environment, within the FCD to determine if steam flashing changes expected pressure drops. Using linear regression, a correlation of expected pressure drop across the autonomous hybrid FCD for mixtures of heavy oil/bitumen, water, and steam was generated. Existing correlations proved inadequate for mixtures containing steam, consistently underestimating pressure drop across the FCD. However, the empirical correlation of this research highly matched laboratory data with an R-squared value of 0.94. A secondary linear model captured modifications in FCD behavior due to steam flashing. This second model also exhibited a strong goodness-of-fit with an R-squared value of 0.96. For both empirical correlations, p-values less than 0.05 were easily obtained, inferring the statistical significance of each correlation. Correlations generated in this research were added to the REVEAL? reservoir simulation package to accurately forecast FCD impact on SAGD well pair performance. Simulating four-year periods of production for SAGD well pairs in Albertan reservoirs consistently show that FCD usage simultaneous improved bitumen recovery by 50% or more and decreased cumulative steam/oil ratios (cSOR) by 12?m3/m3, largely through improved steam chamber conformance and by eliminating steam breakthrough events in the producer. Net Present Value (NPV) analysis of improvements with the additional cost of FCD completion tools unfailingly showed a strong economic argument for the use of FCDs to improve thermal efficiency.Barlas ?im?ek, F., ?a?atay, M.N., 2018. Late Holocene high resolution multi-proxy climate and environmental records from Lake Van, eastern Turkey. Quaternary International 486, 57-72. present the multi-proxy records of centennial scale climate and environmental changes over the last 3.5 ka from a varved sediment core in Lake Van, eastern Turkey. The multi-proxy analyses include ostracod counts, μ-XRF elemental, total organic (TOC) and inorganic carbon, C-N elemental and stable isotopes. For the age model of the core, we use radionuclide (210Pb and 137Cs) analysis and varve counting. Large differences between Accelerator Mass Spectrometry (AMS) radiocarbon dates from TOC and varve ages indicate reservoir ages of 1.2–3.8 ka calBP. Average sedimentation rate for the last 170 years (top 75?mm of the core) ranges between 0.42 and 0.54?mm/yr according to 210Pb dating. Multi-proxy parameters show that Lake Van experienced more arid conditions during the 3.5–1.6 Ka calBP than those during the last 1.6 ka BP. 16 periods of alternating cold/dry and warm/wet intervals with 100–350 years duration are observed over the last 3.5 ka. The Lake Van climate records are conformable with the Lake Nar and the Sofular speleothem records as well as the European historical climate periods including Roman Warm Period (RWP), Dark Age Cold Period (DACP), Medieval Warm Period (MWP) and Little Ice Age (LIA), indicating teleconnections with the North Atlantic system. Human influence is reflected by high detrital influx in the last 700 years.Barry, P.H., Kulongoski, J.T., Landon, M.K., Tyne, R.L., Gillespie, J.M., Stephens, M.J., Hillegonds, D.J., Byrne, D.J., Ballentine, C.J., 2018. Tracing enhanced oil recovery signatures in casing gases from the Lost Hills oil field using noble gases. Earth and Planetary Science Letters 496, 57-67. oil recovery (EOR) and hydraulic fracturing practices are commonly used methods to improve hydrocarbon extraction efficiency; however, the environmental effects of such practices remain poorly understood. EOR is particularly prevalent in oil fields throughout California where water resources are in high demand and the disposal of large volumes of produced water may affect groundwater quality. Consequently, it is essential to better understand the fate of injected (EOR) fluids in California, and other subsurface petroleum systems, as well as any potential effect on nearby aquifer systems. Noble gases can be used as tracers to understand hydrocarbon generation, migration, and storage conditions, as well as the relative proportions of oil and water present in the subsurface. In addition, a noble gas signature diagnostic of injected (EOR) fluids can be readily identified. We report noble gas isotope and concentration data in casing gases from oil production wells in the Lost Hills oil field, northwest of Bakersfield, California, and injectate gas data from the Fruitvale oil field, located within the city of Bakersfield. Casing and injectate gas data are used to: 1) establish pristine hydrocarbon noble-gas signatures and the processes controlling noble gas distributions, 2) characterize the noble gas signature of injectate fluids, 3) trace injectate fluids in the subsurface, and 4) construct a model to estimate EOR efficiency. Noble gas results range from pristine to significantly modified by EOR, and can be best explained using a solubility exchange model between oil and connate/formation fluids, followed by gas exsolution upon production. This model is sensitive to oil–water interaction during hydrocarbon expulsion, migration, and storage at reservoir conditions, as well as any subsequent modification by EOR.Bartlett, R., Elrick, M., Wheeley, J.R., Polyak, V., Desrochers, A., Asmerom, Y., 2018. Abrupt global-ocean anoxia during the Late Ordovician–early Silurian detected using uranium isotopes of marine carbonates. Proceedings of the National Academy of Sciences 115, 5896-5901.: The Late Ordovician mass extinction (LOME) terminated one of the greatest biodiversity radiations in Earth history eliminating ～85% of marine animals, and it is coincident with the first major glaciation of the Phanerozoic. To evaluate LOME origins, we use uranium isotopes from marine limestones as a proxy for global-ocean redox conditions. Our results provide evidence of an abrupt global-ocean anoxic event coincident with the LOME onset and its continuation after the biologic recovery, through peak glaciation, and the following early Silurian deglaciation. These results also provide evidence for widespread ocean anoxia initiating and continuing during icehouse conditions.Abstract: Widespread marine anoxia is hypothesized as the trigger for the second pulse of the Late Ordovician (Hirnantian) mass extinction based on lithologic and geochemical proxies that record local bottom waters or porewaters. We test the anoxia hypothesis using δ238U values of marine limestones as a global seawater redox proxy. The δ238U trends at Anticosti Island, Canada, document an abrupt late Hirnantian ～0.3‰ negative shift continuing through the early Silurian indicating more reducing seawater conditions. The lack of observed anoxic facies and no covariance among δ238U values and other local redox proxies suggests that the δ238U trends represent a global-ocean redox record. The Hirnantian ocean anoxic event (HOAE) onset is coincident with the extinction pulse indicating its importance in triggering it. Anoxia initiated during high sea levels before peak Hirnantian glaciation, and continued into the subsequent lowstand and early Silurian deglacial eustatic rise, implying that major climatic and eustatic changes had little effect on global-ocean redox conditions. The HOAE occurred during a global δ13C positive excursion, but lasted longer indicating that controls on the C budget were partially decoupled from global-ocean redox trends. U cycle modeling suggests that there was a ～15% increase in anoxic seafloor area and ～80% of seawater U was sequestered into anoxic sediments during the HOAE. Unlike other ocean anoxic events (OAE), the HOAE occurred during peak and waning icehouse conditions rather than during greenhouse climates. We interpret that anoxia was driven by global cooling, which reorganized thermohaline circulation, decreased deep-ocean ventilation, enhanced nutrient fluxes, stimulated productivity, which lead to expanded oxygen minimum zones.Batarseh, A.M., Abbott, S.K., Duchoslav, E., Alqarni, A., Blanksby, S.J., Mitchell, T.W., 2018. Discrimination of isobaric and isomeric lipids in complex mixtures by combining ultra-high pressure liquid chromatography with collision and ozone-induced dissociation. International Journal of Mass Spectrometry 431, 27-36. inability of current mass spectrometry techniques to differentiate phospholipid isomers results in a routine under-estimation of phospholipid molecular diversity in complex biological matrices. Recent technological advances in tandem mass spectrometry and ion activation are helping to overcome these limitations, but all rely on tandem mass spectrometry with unit mass-selection and suffer from co-isolation of isobaric or isomeric species. Accordingly, separation of phospholipid isomers and isobars prior to characterization is required to fully delve into the complexity of the lipidome. Here we present a novel two-stage workflow combining reversed-phase ultra-high performance liquid chromatography with ozone-induced dissociation (OzID) and combined-collision- and ozone-induced-dissociation (COzID) that reduces spectral complexity and enables discrimination of lipid isomers and isobars. Application of this technique to the analysis of human red blood cell lipid extracts allowed the separation, or partial separation, of adduct ion and head group isobars as well as double bond and sn-positional isomers affording near complete structural characterization of low abundance lipids, e.g. PC 18:0/20:3(n-6), PS 18:0/20:4(n-6) and PS 20:4(n-6)/18:0 all observed at m/z 834.7. We also introduce a software plug-in that automatically annotates OzID mass spectra to assign the carbon–carbon double bond positions in lipids. This new workflow allows us to delve deeper into the lipidome and represents another valuable tool for the lipidomics toolbox.Baverstock, K., 2018. Commentary on: Cause of Cambrian explosion – Terrestrial or Cosmic? Progress in Biophysics and Molecular Biology 136, 25-26. someone who, unexpectedly, has addressed the question of the origin of life as a scientific issue I am grateful to the editors for the invitation to write a commentary on Steel et al. In the early 1970s, as a physical chemist working in a research unit primarily concerned with biology and genetics, I was sceptical to the point of ridicule of the idea that science had anything at all useful to say about the origin of life. Much later I came to consider the process of abiogenesis in a scientific context as the result of addressing a “white raven” problem, the induction of genomic instability by ionising radiation (Kadhim et al., 1992; Luning et al., 1976), a phenomenon that could not be explained within the prevailing molecular genetic paradigm. The ramifications of a proposed alternative paradigm to incorporate genomic instability into a broad biological context (Annila and Baverstock, 2014) entailed implications for evolution and, it seemed to me at least, a theory of evolution must have a plausible origin for life. In my case, the origin of life theory adopted is ancillary to a hypothesis on how life has evolved based on the laws of physics; it is not an end in itself.I was sceptical of “origin of life theories” as scientific constructs because they seemed to entail if not highly implausible, then essentially unquantifiable, assumptions. This made it impossible to compare one theory with another and so arrive at an opinion as to which was overall the most plausible. How do you compare the assertion that living organisms are travelling galaxy to galaxy on an intergalactic highway, dropping off periodically on Earth, with the improbability that DNA bases will spontaneously concatenate, in a specific order, over a sufficient length, to code for a simple organism? Origin of life theories can only be judged in terms of how they contribute to a wider context. For example, in the evolutionary hypothesis I am pursuing, which emphasises the role of metabolism in the life process over that of replication, a metabolism-first theory, such as that due to Oparin (1953), elaborated in detail by Dyson (1999), is more plausible than theories entailing the spontaneous formation of self-replicating molecules.It is a different matter to make the origin of life theory the central issue, as is the case with Steele et al. and the Panspermia hypothesis they advocate. In the absence of direct evidence of life in the aqueous core of a comet, what should we, the readers, be looking for in Panspermia to be convinced of the authors' arguments and, therefore, abandon all further attempts at understanding evolution with an ancillary context of abiogenesis on Earth? Are claims that meteorites contain what could plausibly be fossilised life forms, or claims that bacteria collected 40 km above the earth are more plausibly incoming alien life than terrestrial life hefted high by violent weather, enough? These are two major arguments advanced in support of Panspermia, but each has been subject to serious questioning and neither has achieved “smoking gun” status. In Steele et al., the authors put forward much evidence that would support an extraterrestrial origin of life, but not evidence that could not be explained in any other terms; definitive evidence. Take for example the claim that carbonised fossils dating back to well before 3.5 billion years ago provide evidence that life existed around deep ocean vents up to 4 billion years ago (Dodd et al., 2017). To quote Dodd et al.'s abstract: “Collectively, these observations are consistent with an oxidized biomass and provide evidence for biological activity in submarine-hydrothermal environments more than 3770 million years ago.” Acknowledging that this is a summary statement, it is already problematic in that it uses the words “consistent with” together with “evidence for”. A feature of the carbonaceous deposits is that they are abnormally rich in the isotope 12C, thus, putatively suggesting they were once living, but as Dodd et al. acknowledge, having been alive is not the only possible explanation for enhanced 12C content. In my view, it would only be “evidence” if it were definitive; only one interpretation possible.In a section headed “Quotations that lead into the paper” the authors cite this quotation in respect of Tardigrades, organisms that are exceptionally resistant to environmental stress: “how on earth did they evolve?”. This quotation heralds a statement: “it goes without saying that Tardigrades … which emerged in the Cambrian period pose a serious challenge to traditional neo-Darwinian thinking”. Earlier on, Tardigrades are described as “space hardy”. The authors then go on to say: “The catalogue of 'living' space-hardy properties is entirely consistent with 'evolutionary natural selective events' acting on Tardigrades evolving in extra-terrestrial space environments.”. Steele et al. then say: “A plausible evidentiary case for proof of Cosmic Panspermia could rest entirely on this one example.”, but is it impossible that Tardigrades evolved on earth?While Steele et al. imply that Tardigrades could be a “smoking gun” for Panspermia I have drawn on the properties of Tardigrades to support my arguments for a terrestrial metabolism-first abiogenesis, suggesting that the adult Tardigrade is an example of multicellular life that does not require the genomic DNA in its somatic cells to function normally, with the exception of replication (Baverstock, 2013). I am suggesting that hatched Tardigrades can be regarded, for practical purposes, as protein only multicellular organisms, thereby giving credence to the idea that single celled protein only life was a precursor to true life in the Oparin-Dyson hypothesis (Dyson, 1982). Tardigrades, I suggest, are resistant to environmental stress because they are eutelic, meaning that the somatic cells do not divide after the Tardigrade hatches. Particularly relevant is the Tardigrade's resistance to the effects of ionising radiation, where damage to the genomic DNA is the first cause of radiation lethality at the cellular level. Adult Tardigrades can withstand several thousand Gy (Beltran-Pardo et al., 2013), much higher doses than Tardigrade egg cells in the early stages of development (Jonsson et al., 2013), where the DNA is needed for cell division. True, this high level of resistance to radiation is a by-product of natural selection\ a “spandrel” (Gould, 2002), as a result of having adopted eutelic growth.Another problematic organism (from the point of view of the neo-Darwinian theory of evolution) that Steele et al. believe can be best explained by Panspermia is the Octopus. Recent evidence has revealed that the Octopus has several genes putatively associated with its high level of intelligence, ability to change colour and to taste through its suckers on its limbs that have no apparent ancestry, i.e., appear de novo in that species (Albertin et al., 2015). This leads Steele et al. to designate these genes as either “borrowed from the future”, or being of extra terrestrial origin as the result of “cryopreserved Octopus eggs”, travelling for several light years from an “adjacent” earth like exo-planet. In fact, the phenomenon of de novo protein coding genes is quite widespread (Kaessmann, 2010). It may be the case that the phenomenon is difficult to explain by the yardstick of the conventional neo-Darwinian paradigm, but Shapiro (2011) has drawn attention to the read/write character of the genome in all species and thus, it is possible that de novo genes arise from splicing together parts of the non-coding DNA. That sort of process is not part of the neo-Darwinian dogma, but it is nevertheless well established (Guerzoni and McLysaght, 2011).Lack of consistency with neo-Darwinism should not be an inviolable criterion upon which to reject abiogenesis on this planet in favour of Panspermia. Here is a different perspective: self-organising pre-life forms (Annila and Baverstock, 2014) constituted of proteins, as proposed by Oparin and developed as a two-stage origin of life theory by Dyson, 1982, 1999, produced the gene coding sequences as a data base for the essential peptides required for cells to function (Nijhout, 1990). Furthermore, the genotype is a read/write organ of the cell (Shapiro, 2011) so it can modify its genome, and finally that cells have agency in the form of awareness of their environments and the ability (intelligence) to act to improve their survival in a hostile environment (e.g. (Baluska and Mancuso, 2009; Bray, 2009; Dreyer and Edelmann, 2018; Vogel and Dussutour, 2016),). It is easy to see that, in such a scenario, there is little to be learned, (or dismissed) about evolution from DNA coding sequences per se and certainly the constraints that might act on self-organisation are unknown. In short, there is still much to understand about how life works without needing to invoke Panspermia.Finally, Steel et al. invoke “punctuated equilibria” as supporting Panspermia. Instead of seeing a continuum of species evolving on earth; long periods of relative stability punctuated by rapid evolution, as proposed by Eldridge and Gould (Eldredge and Gould, 1977), Steele et al. propose the punctuations to be due to injections of comet-borne life onto the planet at times of high cometary bombardment. This would account for the Cambrian explosion, where the fossil evidence of ancestors to the diverse organisms discovered in the Burgess Shale is missing. I too have called on the Eldridge and Gould's punctuated equilibria hypothesis, by proposing that speciation events occur in periods of environmentally induced genomic instability, which represent the punctuations inferred by Eldridge and Gould from the paleontological evidence. The phenomenon of genomic instability, despite its 40-year long history, attracts little attention, possibly because it is a non–Mendelian phenomenon: unstable cells do not truly replicate their phenotypes. This unstable state, where germ cells are concerned, provides an opportunity to explore new phenotypic possibilities to better adapt to a changing ecosystem (Baverstock, 2011). Who can say what could be achieved in a million years of replication by genomically unstable organisms with the ability to influence their own survival?Steele et al. is a long and comprehensive review that urges (it cannot be described as neutral as is usually the case for a scientific review) the reader to accept Panspermia as the basis for the phenomenon of evolution, which they claim will then be “an inquiry into mankind's place in, and relations to, the entire cosmos”. In fact, in that section of the paper (Appendix C) it is argued that adopting Panspermia over neo-Darwinism is akin to the revolution instigated by the great Polish scientist, Copernicus, which led to the ditching of Ptolemaic astronomy in favour of the heliocentric paradigm: if that were the case it would be profound indeed. I am unconvinced for the reasons laid out above. I believe this paper justifies scepticism of the scientific value of stand alone theories of the origin of life: the weight of plausible, but non-definitive, evidence, great though that might be, is not the point. The heliocentric solar system transformed thinking based on a “narrative” about wayward planetary movements, to a self-consistent vision of planets as law abiding entities under Newtonian mechanics. Steele et al. point out shortcomings in neo-Darwinism (e.g., for ignoring the Lamarckian dimension), but have not yet made the case for Panspermia providing the biological equivalent of the heliocentric solar system.ReferencesC.B. Albertin, O. Simakov, T. Mitros, Z.Y. Wang, J.R. Pungor, E. Edsinger-Gonzales, S. Brenner, C.W. Ragsdale, D.S. Rokhsar, The octopus genome and the evolution of cephalopod neural and morphological novelties, Nature, 524 (2015), pp. 220-224A. Annila, K. Baverstock, Genes without prominence: a reappraisal of the foundations of biology, J. R. Soc. Interface, 11 (2014)F. Baluska, S. Mancuso, Deep evolutionary origins of neurobiology: turning the essence of 'neural' upside-down, Commun. Integr. Biol., 2 (2009), pp. 60-65K. Baverstock, A comparison of two cell regulatory models entailing high dimensional attractors representing phenotype, Prog. Biophys. Mol. Biol., 106 (2011), pp. 443-449K. Baverstock, Life as physics and chemistry: a system view of biology, Prog. Biophys. Mol. Biol., 111 (2013), pp. 108-115E. Beltran-Pardo, K.I. Jonsson, A. Wojcik, S. Haghdoost, M. Harms-Ringdahl, R.M. Bermudez-Cruz, J.E. Bernal Villegas, Effects of ionizing radiation on embryos of the tardigrade Milnesium cf. tardigradum at different stages of development, PLoS One, 8 (2013), p. e72098D. Bray, Wetware : a Computer in Every Living Cell, pp. xii, 267 p, Yale University Press, New Haven ; London (2009)M.S. Dodd, D. Papineau, T. Grenne, J.F. Slack, M. Rittner, F. Pirajno, J. O'Neil, C.T. Little, Evidence for early life in Earth's oldest hydrothermal vent precipitates, Nature, 543 (2017), pp. 60-64J. Dreyer, H.G. Edelmann, Root cap - mediated evaluation of soil resistance towards graviresponding roots of maize (Zea mays L.) and the relevance of ethylene, Ann. Bot. (2018), . Dyson, A model for the origin of life, J. Mol. Evol., 18 (1982), pp. 344-350F.J. Dyson, Origins of Life, Cambridge University Press, Cambridge [England] ; New York (1999)N. Eldredge, S.J. Gould, Punctuated equilibria: the tempo and mode of evolution reconsidered, Paleobiology, 3 (1977), pp. 115-151S.J. Gould, The Structure of Evolutionary Theory, pp. xxii, 1433, Belknap, Cambridge, Mass. ; London (2002)D. Guerzoni, A. McLysaght, De novo origins of human genes, PLoS Genet., 7 (2011), p. e1002381Jonsson et al., 2013, K.I. Jonsson, E. Beltran-Pardo, S. Haghordoost, A. Wojcic, R.M. Bermudez-Cruz, J.E. Bernal -Villigas, M. Harms-Ringdahl, Tolerance to gamma-irradiation in eggs of the tardigrade Richtersius coronifer depends on stage of development, J. Limnol., 72 (s1) (2013), pp. 73-79, 10.4081/jlimnol.2013.s1.e9M.A. Kadhim, D.A. Macdonald, D.T. Goodhead, S.A. Lorimore, S.J. Marsden, E.G. Wright, Transmission of chromosomal instability after plutonium alpha-particle irradiation, Nature, 355 (1992), pp. 738-740H. Kaessmann, Origins, evolution, and phenotypic impact of new genes, Genome Res., 20 (2010), pp. 1313-1326K.G. Luning, H. Frolen, A. Nilsson, Genetic effects of 239Pu salt injections in male mice, Mutat. Res., 34 (1976), pp. 539-542H.F. Nijhout, Metaphors and the role of genes in development, Bioessays, 12 (1990), pp. 441-446A.I. Oparin, The Origin of Life, Dover Publications, New York (1953), p. 270J.A. Shapiro, Evolution : a View from the 21st Century, FT Press Science, Upper Saddle River, N.J (2011), pp. xi, 253 pD. Vogel, A. Dussutour, Direct transfer of learned behaviour via cell fusion in non-neural organisms, Proc. Biol. Sci. (2016), p. 283Beall, A.P., Moresi, L., Cooper, C.M., 2018. Formation of cratonic lithosphere during the initiation of plate tectonics. Geology 46, 487-490.’s oldest near-surface material, the cratonic crust, is typically underlain by thick lithosphere (&gt;200 km) of Archean age. This cratonic lithosphere likely thickened in a high-compressional-stress environment, potentially linked to the onset of crustal shortening in the Neoarchean. Mantle convection in the hotter Archean Earth would have imparted relatively low stresses on the lithosphere, whether or not plate tectonics was operating, so a high stress signal from the early Earth is paradoxical. We propose that a rapid transition from heat pipe–mode convection to the onset of plate tectonics generated the high stresses required to thicken the cratonic lithosphere. Numerical calculations are used to demonstrate that an existing buoyant and strong layer, representing depleted continental lithosphere, can thicken and stabilize during a lid-breaking event. The peak compressional stress experienced by the lithosphere is 3×–4× higher than for the stagnant-lid or mobile-lid regimes immediately before and after. It is plausible that the cratonic lithosphere has not been subjected to this high stress state since, explaining its long-term stability. The lid-breaking thickening event reproduces features observed in typical Neoarchean cratons, such as lithospheric seismological reflectors and the formation of thrust faults. Paleoarchean “pre-tectonic” structures can also survive the lid-breaking event, acting as strong rafts that are assembled during the compressive event. Together, the results indicate that the signature of a catastrophic switch from a stagnant-lid Earth to the initiation of plate tectonics has been captured and preserved in the characteristics of cratonic crust and lithosphere.Belli, K.M., Taillefert, M., 2018. Geochemical controls of the microbially mediated redox cycling of uranium and iron. Geochimica et Cosmochimica Acta 235, 431-449. oxidation state is often a primary determinant of the mobility of uranium in subsurface environments, a comprehensive understanding of the redox cycling of uranium is essential to predict the fate of this contaminant. The potential of iron to serve as both a reductant and an oxidant of uranium suggests that remediation strategies which primarily rely on the reduction of the uranyl ion (U(VI)) to the poorly soluble uranous ion (U(IV)) to immobilize uranium in the solid phase may be either enhanced or hindered depending on the biogeochemical transformations of iron. To identify the geochemical controls of both uranium and iron redox cycling, batch incubations with the model metal-reducing bacterium Shewanella putrefaciens were conducted with either U(VI), ferrihydrite, or both as terminal electron acceptors, and concentrations of dissolved inorganic carbon (DIC), calcium, and silica were varied to alter aqueous uranyl speciation and secondary mineralization pathways of ferrihydrite. The presence of ferrihydrite increased the pseudo-first order rate constant of initial uranium removal from solution in nearly all conditions compared to uranium-only controls due to a combination of abiotic U(VI) reduction by Fe(II) and solid-phase association of uranium with secondary mineralization products of ferrihydrite. Following an initial period of uranium reduction, U(IV) was oxidized by ferrihydrite which led to a rebound in dissolved uranium. Once ferrihydrite was completely consumed by microbial respiration and secondary mineralization, uranium was again removed from solution via reductive precipitation and association with secondary mineralization products. DIC and calcium enhanced the oxidative dissolution of U(IV) solids but did not affect the redox potential of the U(VI)/U(IV) redox couple despite the formation of aqueous uranyl carbonate and calcium-uranyl carbonate species. Instead, removal of dissolved Fe(II) from solution and the accompanied shift in the redox potential of the Fe(III)/Fe(II) redox couple was responsible for the abrupt shift in iron acting as a reductant of U(VI) to an oxidant of U(IV). The removal of dissolved Fe(II) via siderite precipitation at the highest DIC concentration and in the presence of calcium enhanced the oxidation of U(IV), and the presence of silica limited the conversion of ferrihydrite to magnetite and sustained U(IV) oxidation. A kinetic model was developed which could reproduce incubation time series of uranium and iron speciation provided the thermodynamic favorability of abiotic uranium-iron redox cycling was accounted for. The modeling exercise revealed that the non-uraninite U(IV) solids formed in the incubations have a redox potential approximately 84?mV lower than that of amorphous uraninite, highlighting the need for a thermodynamic characterization of non-uraninite U(IV) solids. The results of this study identify dissolved Fe(II) concentration as the primary geochemical control of the role of iron in uranium redox cycling at moderate to high DIC concentrations and emphasize the importance of considering this parameter when designing site-specific, in situ bioremediation strategies.Bengelsdorf, F.R., Beck, M.H., Erz, C., Hoffmeister, S., Karl, M.M., Riegler, P., Wirth, S., Poehlein, A., Weuster-Botz, D., Dürre, P., 2018. Bacterial anaerobic synthesis gas (syngas) and CO2+H2 fermentation. Advances in Applied Microbiology 103, 143-221. bacterial gas fermentation gains broad interest in various scientific, social, and industrial fields. This microbial process is carried out by a specific group of bacterial strains called acetogens. All these strains employ the Wood–Ljungdahl pathway but they belong to different taxonomic groups. Here we provide an overview of the metabolism of acetogens and naturally occurring products. Characteristics of 61 strains were summarized and selected acetogens described in detail. Acetobacterium woodii, Clostridium ljungdahlii, and Moorella thermoacetica serve as model organisms. Results of approaches such as genome-scale modeling, proteomics, and transcriptomics are discussed. Metabolic engineering of acetogens can be used to expand the product portfolio to platform chemicals and to study different aspects of cell physiology. Moreover, the fermentation of gases requires specific reactor configurations and the development of the respective technology, which can be used for an industrial application. Even though the overall process will have a positive effect on climate, since waste and greenhouse gases could be converted into commodity chemicals, some legislative barriers exist, which hamper successful exploitation of this technology.Berthod, A., Ruiz-?ngel, M.J., Carda-Broch, S., 2018. Recent advances on ionic liquid uses in separation techniques. Journal of Chromatography A 1559, 2-16. molten organic salts with melting point below 100°C, commonly called ionic liquids (ILs) have found numerous uses in separation sciences due to their exceptional properties as non molecular solvents, namely, a negligible vapor pressure, a high thermal stability, and unique solvating properties due to polarity and their ionic character of molten salts. Other properties, such as viscosity, boiling point, water solubility, and electrochemical window, are adjustable playing with which anion is associated with which cation. This review focuses on recent development of the uses of ILs in separation techniques actualizing our 2008 article (same authors, J. Chromatogr. A, 1184 (2008) 6–18) focusing on alkyl methylimidazolium salts. These developments include the use of ILs in nuclear waste reprocessing, highly thermally stable ILs that allowed for the introduction of polar gas chromatography capillary columns able to work at temperature never seen before (passing 300°C), the use of ILs in liquid chromatography and capillary electrophoresis, and the introduction of tailor-made ILs for mass spectrometry detection of trace anions at the few femtogram level. The recently introduced deep eutectic solvents are not exactly ILs, they are related enough so that their properties and uses in countercurrent chromatography are presented.Beti, D.R., Thul, D.J., Ring, T.A., McLennan, J.D., Levey, R., 2018. A new method of source and reservoir rock pyrolysis to determine the boiling point distribution of petroleum in rock samples. Journal of Petroleum Science and Engineering 170, 71-80. paper presents a new method of source and reservoir rock pyrolysis used to understand the boiling point distribution of petroleum in rock samples. Experiments and simulations of the new incremental S1 method were performed on a range of rock types and API gravities (Black oil?<?40, Volatile oil 40–45, Gas condensate?≥?50 and Wet gas?>?50). Comparison of the results from experiments and simulations are presented. The boiling point distribution results from the new incremental method can be used to infer the carbon number distribution of oil present in rock samples. However, the boiling point distribution data from the incremental S1 method is not adequate to determine the API Gravity of oil present in rock samples. Refractive index (RI) and density of oil have a straight line correlation. The boiling point distribution data from the Incremental S1 can be used in conjunction with the refractive index data to predict the composition of oil present in rock samples.Bi, S., Zheng, X., Wang, X., Cignetti, N.E., Yang, S., Wible, J.R., 2018. An Early Cretaceous eutherian and the placental–marsupial dichotomy. Nature 558, 390-395. estimates of the divergence of placental and marsupial mammals and their broader clades (Eutheria and Metatheria, respectively) fall primarily in the Jurassic period. Supporting these estimates, Juramaia—the oldest purported eutherian—is from the early Late Jurassic (160 million years ago) of northeastern China. Sinodelphys—the oldest purported metatherian—is from the same geographic area but is 35 million years younger, from the Jehol biota. Here we report a new Jehol eutherian, Ambolestes zhoui, with a nearly complete skeleton that preserves anatomical details that are unknown from contemporaneous mammals, including the ectotympanic and hyoid apparatus. This new fossil demonstrates that Sinodelphys is a eutherian, and that postcranial differences between Sinodelphys and the Jehol eutherian Eomaia—previously thought to indicate separate invasions of a scansorial niche by eutherians and metatherians—are instead variations among the early members of the placental lineage. The oldest known metatherians are now not from eastern Asia but are 110 million years old from western North America, which produces a 50-million-year ghost lineage for Metatheria.Bielicki, J.M., Langenfeld, J.K., Tao, Z., Middleton, R.S., Menefee, A.H., Clarens, A.F., 2018. The geospatial and economic viability of CO2 storage in hydrocarbon depleted fractured shale formations. International Journal of Greenhouse Gas Control 75, 8-23. depleted fractured shale (HDFS) formations could be attractive for geologic carbon dioxide (CO2) storage. Shale formations may be able to leverage existing infrastructure, have larger capacities, and be more secure than saline aquifers. We compared regional storage capacities and integrated CO2 capture, transport, and storage systems that use HDFS with those that use saline aquifers in a region of the United States with extensive shale development that overlies prospective saline aquifers. We estimated HDFS storage capacities with a production-based method and costs by adapting methods developed for saline aquifers and found that HDFS formations in this region might be able to store with less cost an estimated ～14× more CO2 on average than saline aquifers at the same location. The potential for smaller Areas of Review and less investment in infrastructure accounted for up to 84% of the difference in estimated storage costs. We implemented an engineering-economic geospatial optimization model to determine and compare the viability of storage capacity for these two storage resources. Across the state-specific and regional scenarios we investigated, our results for this region suggest that integrated CCS systems using HDFS could be more centralized, require less pipelines, prioritize different routes for trunklines, and be 6.4–6.8% ($5-10/tCO2) cheaper than systems using saline aquifers. Overall, CO2 storage in HDFS could be technically and economically attractive and may lower barriers to large scale CO2 storage if they can be permitted.Bjerg, J.T., Boschker, H.T.S., Larsen, S., Berry, D., Schmid, M., Millo, D., Tataru, P., Meysman, F.J.R., Wagner, M., Nielsen, L.P., Schramm, A., 2018. Long-distance electron transport in individual, living cable bacteria. Proceedings of the National Academy of Sciences 115, 5786-5791.: Cable bacteria are centimeter-long, multicellular filamentous bacteria, which are globally occurring in marine and freshwater sediments. Their presence coincides with the occurrence of electrical fields, and gradients of oxygen and sulfide that are best explained by electron transport from sulfide to oxygen along the cable-bacteria filaments, implying electric conductance by living bacteria over centimeter distances. Until now, all indications for such long-distance electron transport were derived from bulk sediment incubations. Here we present measurements on individual cable-bacteria filaments that allow us to quantify a voltage drop along cable-bacteria filaments and show a transport of electrons over several millimeters. This is orders of magnitude longer than previously known for biological electron transport.Abstract: Electron transport within living cells is essential for energy conservation in all respiring and photosynthetic organisms. While a few bacteria transport electrons over micrometer distances to their surroundings, filaments of cable bacteria are hypothesized to conduct electric currents over centimeter distances. We used resonance Raman microscopy to analyze cytochrome redox states in living cable bacteria. Cable-bacteria filaments were placed in microscope chambers with sulfide as electron source and oxygen as electron sink at opposite ends. Along individual filaments a gradient in cytochrome redox potential was detected, which immediately broke down upon removal of oxygen or laser cutting of the filaments. Without access to oxygen, a rapid shift toward more reduced cytochromes was observed, as electrons were no longer drained from the filament but accumulated in the cellular cytochromes. These results provide direct evidence for long-distance electron transport in living multicellular bacteria.Bjerrum, C.J., 2018. Sea level, climate, and ocean poisoning by sulfide all implicated in the first animal mass extinction. Geology 46, 575-576. decades ago, Newell (1967) suggested a strong relationship between marine mass extinction and eustatic sea-level fall, and proposed loss of habitable shelf area as the primary driver. However, many extinctions are now linked with global warming and marine anoxia, which go hand in hand with marine transgressions (Hallam and Wignall, 1999, and references therein; Bond and Grasby, 2017). In contrast, Zou et al. (2018, p. 535 in this issue of Geology), now offer a much more nuanced picture, with expanding toxic sulfide conditions during cooling, and falling sea level during the first of the big five mass extinctions, the Late Ordovician mass extinction (LOME; ca. 445 Ma). Paradoxically, the LOME is the only one of the big five extinctions that seems to coincide with glaciations, with a double blow to metazoan-based communities. Excellent reviews have mapped out the taxonomic extinctions and ecological severity for the LOME event (Harper et al., 2014, and references therein).Two main mechanisms have previously been proposed for the two extinction intervals of the LOME (Harper et al., 2014; Bond and Grasby, 2017), where the least controversial invokes marine anoxia during sea-level rise and global warming during the latter extinction interval (LOMEI-2). The first extinction interval (LOMEI-1) is, however, more controversial, particularly with respect to oxygenation. Many research groups link LOMEI-1 to rapid glacial sea-level lowering, cooling, and increased oxygenation of the open ocean. These models build, in part, on the widespread facies change from black to gray shales, as well as on nitrogen isotope data (Melchin et al., 2013). While possibly explaining the disappearance of the main extinction victims on the outer shelf-slope and in the upper oxygen minimum zone (OMZ), oxygenation is a difficult kill mechanism for high-latitude, cool-water taxa (Harper et al., 2014). Other research groups have proposed expansion of anoxic waters onto the outer shelf and slope during the cooling as the prime killer, based on redox geochemistry and pyrite sulfur isotopes (Hammarlund et al., 2012; Harper et al., 2014). In this scenario, the widespread change from black to gray shales reflects glacially lowered sea level, which pushed the chemocline deeper than the continental shelf observation window. Invariant sulfate isotope data, together with super heavy sulfide, could be interpreted as oxidation of a deep ocean sulfide reservoir (Jones and Fike, 2013; Kah et al., 2016). Alternatively, the sulfur isotope anomaly could be interpreted as a result of decreased fractionation during increased microbial sulfate reduction prompted by increased glacial ocean nutrients and productivity (Jones and Fike, 2013). Molybdenum and uranium isotopes suggest extensive ocean anoxia prior to LOMEI-1, and subsequent intensified oxygenation during the glacial interval (Lu et al., 2017). The latter interpretation is controversial, as it stems from a highly variable redox setting in the Yangtze Sea, China. Adding to the controversy, sequence stratigraphic concepts and a Pliocene-Pleistocene glacial analogy has led to the proposal that known LOME sections are incomplete, and missing interglacial high stands (Ghienne et al., 2014). The implication is that, perhaps, the LOMEI-1 also occurred during global warming and rising sea level, just like LOMEI-2 and other mass extinctions.A problem with most studies to date is that each only gives a snapshot for a given basin or climate zone, and that sea-level change results in a “sliding” observation window in terms of paleo–water depth. A better understanding of the kill mechanism that caused the LOME can come from studies using multiple high-resolution sections in basin paleo-depth transects. Precisely such an undertaking is presented by Zou et al. They identify a reduction in chemical weathering interpreted as a response to glacial cooling. In addition, they use iron speciation and redox-sensitive metals to map changes in the extent of oxygen and anoxia, as well as euxinic conditions associated with toxic sulfide in the water column.Perhaps not surprisingly, the authors find extensive ferruginous anoxia prior to the LOME in the Yangtze Sea, where the subtropical tradewind belt caused upwelling. Zou et al. observed a weathering decrease during LOMEI-1, suggesting the onset of a glacial weathering regime. They thus tie the first extinction phase to increased cooling and sea-level lowering, resulting in a decreased warm-water eco space when, in particular, low-latitude plankton went extinct. Then, what about the other victims?Concomitant with cooling, Zou et al. found that the inner shelf was oxygenated as expected when the chemocline was pushed down during glacial sea-level fall. Interestingly, the decrease in weathering (cooling) is also associated with increasing water-column sulfide in mid-shelf and deeper settings. The latter explains the observed dying off of outer shelf-slope benthic faunas. However, increasing sulfide in an upwelling setting is surprising during cooling and sea-level lowering.During the last glacial lowstand (ca. 20 ka) the OMZs of upwelling systems around the world seem to have been more oxygenated than during the interglacial (Jaccard and Galbraith, 2012; Scholz et al., 2014). In contrast, the deeper slope and abyss was more dysoxic, with a higher accumulation of organic carbon (Cartapanis et al., 2016). These changes presumably resulted from a strengthened oxygenated, equatorward undercurrent and reduced biological respiration in the upper water column, in response to lower metabolic activity at lower temperatures.Ongoing research offers further insight into the oxygenation and biogeochemical response to variable shelf width during sea-level change (Fig. 1). Shelf and open ocean systems respond oppositely in the steady state with fixed input flux boundary conditions. Consistent with these results, three-dimensional regional ocean model shows that upwelling systems respond much more readily to shelf width changes than the average global shelf (cf. Al Azhar et al., 2013; M. Al Azhar and C.J. Bjerrum, our data.). These results contrast with Zou et al.’s observation of increased shelf anoxia during cooling and sea-level fall, and not during sea-level rise. The contrast indicates that other feedback relationships were at work. Reduced glacial weathering and limited increase in tradewind intensity result in no enhancement of nutrient delivery to the shelf system, underlining the observed increase in sulfide levels (Pohl et al., 2017; Pogge von Strandmann et al., 2017; Zou et al., 2018). Shelf exposure in a system with no rooted vegetation may result in further “shelf unloading”, increasing the oxygen demand in the deep ocean (Broecker, 1982). Lower temperatures further act to decrease metabolic activity, pushing the oxygen demand deeper into the ocean. When mapping the Earth system feedback, it is seen that sea-level change in the short term results in a negative feedback centered on the shelf, whereas sea-level change on the long term may be a positive feedback (see Broecker, 1982) (Fig. 2). From the results presented by Zou et al., it seems that long-term open ocean response “won” in expanding the OMZ with toxic sulfide during cooling during LOMEI-1. But perhaps the picture is more complicated.Remember that LOMEI-1 could have occurred during global warming and rising sea level, just as LOMEI-2 did (Ghienne et al., 2014). Inspecting in detail the data of Zou et al., we see a few more intense weathering points just at the base of LOMEI-1. A short-lived interglacial could have resulted in intense weathering and sea-level rise, as also shown in temperature and glacial volume proxies (Finnegan et al., 2011). If so, it may not be the glacial interval that drove the first of the big five mass extinctions, but rather short-lived increasing temperature and sea-level rise.Regardless, the thorough data set presented by Zou et al. presents several valuable observations. It confirms records from an upwelling location in western Laurentia, where sustained anoxia persisted though LOMEI-1 (Ahm et al., 2017). And their data set creates a paradox in how upwelling systems respond to glacial conditions during the Late Ordovician Mass Extinction.Blom, J., Soenen, H., Katsiki, A., Van den Brande, N., Rahier, H., van den Bergh, W., 2018. Investigation of the bulk and surface microstructure of bitumen by atomic force microscopy. Construction and Building Materials 177, 158-169., the heavy residue of crude oil, can display a rich microscale morphology, including so-called Bee structures. The use of Atomic Force Microscopy (AFM) measurements in literature strongly indicates that the appearance of Bee structures is related to the presence of paraffin wax crystals. Most studies have investigated standard bitumen surfaces when cooling bitumen in an air atmosphere. Only a few investigations have analysed surfaces formed in other media or have analysed fractured surfaces which relate to the bulk morphology. Although considerable research has focussed on identifying Bee structures, less attention has been paid to the Bee structure morphology of different bitumen types and the relations to other binder parameters. The comparison between the micro morphology of the air-oil interface compared to the bulk phase volume has been studied even less.In this experimental study, five bitumen samples were selected based on differences in their natural wax content. Both the air-cooled surface interface and fractured surfaces were characterised using AFM in tapping mode. All the air-cooled surfaces revealed Bee structures, except the wax-free bitumen, which did not display the presence of any Bee structure. None of the fracture surfaces revealed Bee structures. Reheating a fractured surface of a wax-containing bitumen transformed the morphology into Bee structures.The experiments demonstrate that Bee structures are present in different binders but display very different shapes and sizes. However: image analysis indicates that the unit cell inside these structures is rather constant and independent of the binder type. This work confirms a relationship between natural wax and Bee structures and it also shows that Bee structures, as such, are a surface phenomenon which is not present in the bulk phase volume of samples.Bobay, L.-M., Ochman, H., 2018. Biological species in the viral world. Proceedings of the National Academy of Sciences 115, 6040-6045.: The biological species concept (BSC) has served as the basis for defining species for over 75 years. Members of a biological species are defined by their ability to exchange genetic material, and it was originally thought that asexual lineages were not amenable to species-level classification based on the BSC since clonal individuals are reproductively isolated from one another. In this study, we demonstrate that the rates and patterns of gene exchange in acellular organisms (viruses and bacteriophages) allow the assignment of true biological species, an essential step to organizing the tree of life. Our results show that a universal species definition, based on the BSC, can be used to define biological species in all major lifeforms.Abstract: Due to their dependence on cellular organisms for metabolism and replication, viruses are typically named and assigned to species according to their genome structure and the original host that they infect. But because viruses often infect multiple hosts and the numbers of distinct lineages within a host can be vast, their delineation into species is often dictated by arbitrary sequence thresholds, which are highly inconsistent across lineages. Here we apply an approach to determine the boundaries of viral species based on the detection of gene flow within populations, thereby defining viral species according to the biological species concept (BSC). Despite the potential for gene transfer between highly divergent genomes, viruses, like the cellular organisms they infect, assort into reproductively isolated groups and can be organized into biological species. This approach revealed that BSC-defined viral species are often congruent with the taxonomic partitioning based on shared gene contents and host tropism, and that bacteriophages can similarly be classified in biological species. These results open the possibility to use a single, universal definition of species that is applicable across cellular and acellular lifeforms.Boehnke, P., Bell, E.A., Stephan, T., Trappitsch, R., Keller, C.B., Pardo, O.S., Davis, A.M., Harrison, T.M., Pellin, M.J., 2018. Potassic, high-silica Hadean crust. Proceedings of the National Academy of Sciences 115, 6353-6356.: To understand early Earth’s habitability, we need to know when the continental crust first formed. However, due to the combined actions of plate tectonics and erosion, most of the evidence of the early crust has been destroyed. To shed light on this debate, we analyzed the strontium isotopic composition of apatite inclusions in zircons from Nuvvuagittuq, Canada, where independent evidence suggests a crust-forming event prior to 4.2 Ga, possibly as early as 4.4 Ga. Our results show that this early crust had a high Rb/Sr ratio and therefore a high silica content. This suggests that the early Earth was capable of forming continental crust within <350 million y of solar system formation.Abstract: Understanding Hadean (>4 Ga) Earth requires knowledge of its crust. The composition of the crust and volatiles migrating through it directly influence the makeup of the atmosphere, the composition of seawater, and nutrient availability. Despite its importance, there is little known and less agreed upon regarding the nature of the Hadean crust. By analyzing the 87Sr/86Sr ratio of apatite inclusions in Archean zircons from Nuvvuagittuq, Canada, we show that its protolith had formed a high (>1) Rb/Sr ratio reservoir by at least 4.2 Ga. This result implies that the early crust had a broad range of igneous rocks, extending from mafic to highly silicic compositions.Boglaienko, D., Tansel, B., 2018. Classification of oil–particle interactions in aqueous environments: Aggregate types depending on state of oil and particle characteristics. Marine Pollution Bulletin 133, 693-700. are significant differences in the aggregation mechanisms and types of aggregates that form by oil-particle interactions in marine and laboratory environments depending on the state of oil (i.e., dissolved, emulsified, floating), size and type of particles involved (i.e., colloidal, granular, organic, inorganic), oil-particle interaction mechanisms, and settling/suspension characteristics. Distinct characteristics of oil-particle aggregates that form by interaction of granular particles with floating oil separate them from the well-known oil-colloidal particle aggregates (OcPA), which are sometimes called Pickering emulsions. Unlike OcPA, which involve emulsified oil (entrained oil droplets suspended in the water column) and colloidal particles, the oil-granular particle aggregates (OgPA) involve the floating oil and granular particles. Here, to clarify the differences and similarities between the two types of aggregates (OcPA and OgPA), we present classification of oil aggregates, drawing attention to important characteristics of OcPA, marine oil snow (MOS), and OgPA.Bogomolov, A.K., Sidorenko, S.A., 2018. The features of the transformation of organic matter of Precambrian carboniferous rocks of the Ukrainian crystalline shield. Moscow University Geology Bulletin 73, 150-160. main features of the transformation of organic matter (OM) in the greenschist, amphibolite, and granulite facies of metamorphism are considered based on the example of the Ukrainian crystal shield. The occurrence area and OM content in highly carbonaceous ancient rocks are characterized. The composition of primary sedimentary rocks and the processes of accumulation of biophile elements under the OM transformation are reconstructed. Original Russian Text ? A.Kh. Bogomolov, Sv.A. Sidorenko, 2018, published in Vestnik Moskovskogo Universiteta, Seriya 4: Geologiya, 2018, No. 1, pp. 44–53.Bonelli, N., Montis, C., Mirabile, A., Berti, D., Baglioni, P., 2018. Restoration of paper artworks with microemulsions confined in hydrogels for safe and efficient removal of adhesive tapes. Proceedings of the National Academy of Sciences 115, 5932.: From Dead Sea Scrolls to Federico Fellini and Lucio Fontana drawings, pressure-sensitive tapes (PSTs) have been used as adhesive fasteners or as part of temporary conservation treatments that frequently became permanent. Their safe and efficient removal poses ethical and aesthetic questions: Adhesive tape residues damage the paper substrate and, due to discoloring, prejudice the artwork enjoyment and conservation. Selective removal without affecting the underlying support is challenging and often impossible. We tackled this issue from a physicochemical and a colloidal perspective, by designing a system where nanosized solvent droplets are confined within a hydrogel. This method has the potential to revolutionize the approaches used so far in the removal of PSTs and coatings from a plurality of materials.Abstract: The presence of pressure-sensitive tapes (PSTs) on paper artworks, either fortuitous or specifically applied for conservation purposes, is one of the most frequent and difficult issues encountered during restoration. Aged PSTs can damage or disfigure artworks, compromising structural integrity, readability, and enjoyment. Current procedures are often inherently hazardous for artistic media and paper support. Challenged by the necessity to remove PSTs from a contemporary and an ancient drawing (20th century, by artists da Silva and Hayter, and a 16th-century drawing of one figure from the Sistine Chapel by Michelangelo), we addressed this issue from a physicochemical perspective, leveraging colloid and interface science. After a characterization of the specific PSTs present on the artifact, we selected a highly water-retentive hydrogel as the host of 23% wt/wt of “green” organic solvents uniformly dispersed within the gel in the form of nanosized droplets. The double confinement of the organic solvent in the nanodroplets and into the gel network promotes a tailored, controlled removal of PSTs of different natures, with virtually no interaction with the solvent-sensitive artwork. This noninvasive procedure allows complete retrieval of artwork readability. For instance, in the ancient drawing, the PST totally concealed the inscription, “di mano di Michelangelo” (“from Michelangelo’s hand”), a possibly false attribution hidden by a collector, which is now perfectly visible and whose origin is currently under investigation. Remarkably, the same methodology was successful for the removal of aged PST adhesive penetrated inside paper fibers of a drawing from the celebrated artist Lucio Fontana.Boote, D.R.D., Sachsenhofer, R.F., Tari, G., Arbouille, D., 2018. Petroleum provinces of the Paratethyan region. Journal of Petroleum Geology 41, 247-297. crustal collision between Africa and Eurasia in the middle Eocene – early Oligocene enclosed a semi‐restricted Paratethyan seaway of linked basins and platforms across a region stretching from the Eastern Alps to the South Caspian Sea. As the African Plate continued to advance north during the later Neogene, the seaway shrank into a series of more isolated basins separated by the rising Alpine – Carpathian – Caucasus fold‐thrust belts. Organic‐rich oil‐prone Paratethyan source rocks of middle Eocene (Kuma Formation and equivalents) and Oligocene – early Miocene (Maikop and Menilite Beds) ages, and more gas‐prone post‐orogenic mid‐upper Miocene shales, subsequently charged over 2500 accumulations across the region with combined recoverable reserves of 95 billion brl oil‐equivalent (B boe). These accumulations are clustered in discrete petroleum provinces, each with a distinct tectono‐stratigraphic architecture and comprised of one or more petroleum systems. The provinces can be grouped into five broad categories: Bordes, L., Fullagar, R., Prinsloo, L.C., Hayes, E., Kozlikin, M.B., Shunkov, M.V., Derevianko, A.P., Roberts, R.G., 2018. Raman spectroscopy of lipid micro-residues on Middle Palaeolithic stone tools from Denisova Cave, Siberia. Journal of Archaeological Science 95, 52-63. spectroscopy is a powerful method for detecting micro-residues on stone tools. To further develop techniques for determining stone tool function, we devised a methodology using Raman microscopy to analyse in situ micro-residues before conventional usewear study. We analysed 18 stone artefacts collected in situ from Denisova Cave in Siberia, where excellent organic residue preservation is expected. We report here details of saturated and unsaturated fatty acids identified on eight stone tools from the Middle Palaeolithic levels. The spatial distribution of smeared fatty acids shows strong correlation with spatial distributions of usewear (particularly use-polish, but also striations, edge rounding and scarring) on each tool, demonstrating that these micro-residues are likely associated with prehistoric tool contact with animal tissue. We compared Raman spectra and the types, abundance and distribution of micro-residues on the Denisova Cave artefacts with those on modern experimental stone tools (with known function). The results provide further support for Middle Palaeolithic processing of animal tissue and probable skin scraping at Denisova Cave.Borisov, D.N., Tazeev, D.I., Milordov, D.V., Mironov, N.A., Borisova, Y.Y., Yakubov, M.R., Beregovoy, A.N., Amerkhanov, M.I., Khisamov, R.S., 2018. Physical modeling of the composite solvent injection to improve the ultra-viscous oil recovery efficiency steam-assisted gravity drainage. Journal of Petroleum Science and Engineering 169, 337-343. experiments carried out on a physical model of reservoir of ultra-viscous oil have revealed features of oil displacement in various variants of the composite solvent and steam injection. In order to avoid precipitation of asphaltenes, the employment of inhibitors has been rationalized and their minimum fraction in displacement fluid has been determined. The effect of the sequence of solvent and vapor injection on the dynamics of ultra-viscous oil recovery has been investigated. The effect of clay and water in the rock on the rate of oil displacement and the ultimate oil recovery factor has been evaluated.Botting, J.P., Muir, L.A., Wang, W., Qie, W., Tan, J., Zhang, L., Zhang, Y., 2018. Sponge-dominated offshore benthic ecosystems across South China in the aftermath of the end-Ordovician mass extinction. Gondwana Research 61, 150-171. benthic communities were sparse after the end-Ordovician mass extinction. The recent discovery of diverse, abundant sponges in south-eastern China (Anhui and Zhejiang provinces) that flourished during the Hirnantian (Late Ordovician) post-extinction interval raises questions over the extent and ecological significance of the sponge community at that time. This paper dramatically expands the scale of the Hirnantian sponge fauna within South China, with seven new occurrences across 2000?km. These occurrences cross the Ordovician–Silurian boundary interval in the marginal and submerged platform areas of the Yangtze Sea in Jiangsu, Hubei, Hunan, Chongqing and Sichuan provinces. In condensed sections (platform-margin facies), the occurrences are normally represented by extensive spiculite layers, but several sites yield entire, exceptionally preserved body fossils; at Ganggangshan (near Nanjing, Jiangsu Province), such preservation is abundant. The new occurrences are combined with palaeogeographic and tectonic reconstructions to produce a model for the distribution and preservation of the sponge fauna. We argue that the exceptional preservation was due largely to nepheloid layers that were generated during rapid post-glacial transgression that flooded the weathered land surface of the uplifted Cathaysia Block. Nepheloid-layer collapse led to rapid deposition of suspended sediment within the deeper parts of the intra-plate, restricted basin and on adjacent platform margins and slopes. The suspended sediment influx also introduced abundant nutrients to the water column, as indicated by a significant δ13C excursion during the sponge-bearing mudstone interval at Ganggangshan. The combined sponge assemblage was dominant over large areas of the Hirnantian offshore sea floor across South China. We predict that similar occurrences with exceptional preservation will also be found in other continental blocks: abundant articulated sponges may be encountered particularly in restricted basin successions containing rapidly deposited graptolitic mudstones near the Ordovician–Silurian boundary.Bouvier, L.C., Costa, M.M., Connelly, J.N., Jensen, N.K., Wielandt, D., Storey, M., Nemchin, A.A., Whitehouse, M.J., Snape, J.F., Bellucci, J.J., Moynier, F., Agranier, A., Gueguen, B., Sch?nb?chler, M., Bizzarro, M., 2018. Evidence for extremely rapid magma ocean crystallization and crust formation on Mars. Nature 558, 586-589. formation of a primordial crust is a critical step in the evolution of terrestrial planets but the timing of this process is poorly understood. The mineral zircon is a powerful tool for constraining crust formation because it can be accurately dated with the uranium-to-lead (U–Pb) isotopic decay system and is resistant to subsequent alteration. Moreover, given the high concentration of hafnium in zircon, the lutetium-to-hafnium (176Lu–176Hf) isotopic decay system can be used to determine the nature and formation timescale of its source reservoir. Ancient igneous zircons with crystallization ages of around 4,430 million years (Myr) have been reported in Martian meteorites that are believed to represent regolith breccias from the southern highlands of Mars. These zircons are present in evolved lithologies interpreted to reflect re-melted primary Martian crust , thereby potentially providing insight into early crustal evolution on Mars. Here, we report concomitant high-precision U–Pb ages and Hf-isotope compositions of ancient zircons from the NWA?7034 Martian regolith breccia. Seven zircons with mostly concordant U–Pb ages define 207Pb/206Pb dates ranging from 4,476.3?±?0.9 Myr ago to 4,429.7?±?1.0 Myr ago, including the oldest directly dated material from Mars. All zircons record unradiogenic initial Hf-isotope compositions inherited from an enriched, andesitic-like crust extracted from a primitive mantle no later than 4,547 Myr ago. Thus, a primordial crust existed on Mars by this time and survived for around 100 Myr before it was reworked, possibly by impacts, to produce magmas from which the zircons crystallized. Given that formation of a stable primordial crust is the end product of planetary differentiation, our data require that the accretion, core formation and magma ocean crystallization on Mars were completed less than 20 Myr after the formation of the Solar System. These timescales support models that suggest extremely rapid magma ocean crystallization leading to a gravitationally unstable stratified mantle, which subsequently overturns, resulting in decompression melting of rising cumulates and production of a primordial basaltic to andesitic crust.Bramucci, A.R., Labeeuw, L., Orata, F.D., Ryan, E.M., Malmstrom, R.R., Case, R.J., 2018. The bacterial symbiont Phaeobacter inhibens shapes the life history of its algal host Emiliania huxleyi. Frontiers in Marine Science 5, 188. doi: 110.3389/fmars.2018.00188. microbes form host-associated biofilm communities that are shaped by complex interactions between bacteria and their host. The roseobacter Phaeobacter inhibens exploits both symbiotic and pathogenic niches while interacting with its microalgal host Emiliania huxleyi. During co-cultivation over extended periods with E. huxleyi, we show that P. inhibens selectively kills two host cell types, the diploid calcifying strain and the haploid flagellated strain. Meanwhile, various non-calcifying diploid strains are resistant to this pathogen or the pathogen is avirulent to this cell type. This differential pathogenesis has the potential of dramatically altering the composition of E. huxleyi blooms, which are typically dominated by the roseobacter-susceptible calcifying strain. This cell type makes calcite plates, which are an important sink in the marine carbon cycle and forms part of the marine paleobotanic record. P. inhibens kills the haploid cells, which have been proposed as critical to the survival of the algae, as they readily escape both eukaryotic predation and viral infection. Consequently, bacteria such as P. inhibens could influence E. huxleyi’s life history by selective pathogenesis, thereby altering the composition of cell types within its populations and its bloom-bust lifestyle.Bridges, K.N., Lay, C.R., Alloy, M.M., Gielazyn, M.L., Morris, J.M., Forth, H.P., Takeshita, R., Travers, C.L., Oris, J.T., Roberts, A.P., 2018. Estimating incident ultraviolet radiation exposure in the northern Gulf of Mexico during the Deepwater Horizon oil spill. Environmental Toxicology and Chemistry 37, 1679-1687. of barrels of oil were released into the Gulf of Mexico following the 2010 explosion of the Deepwater Horizon oil rig. Polycyclic aromatic hydrocarbons (PAHs) are toxic components of crude oil, which may become more toxic in the presence of ultraviolet (UV) radiation, a phenomenon known as photo?induced toxicity. The Deepwater Horizon spill impacted offshore and estuarine sites, where biota may be co?exposed to UV and PAHs. Penetration of UV into the water column is affected by site?specific factors. Therefore, measurements and/or estimations of UV are necessary when one is assessing the risk to biota posed by photo?induced toxicity. We describe how estimates of incident UV were determined for the area impacted by the Deepwater Horizon oil spill, using monitoring data from radiometers near the spill, in conjunction with reference spectra characterizing the composition of solar radiation. Furthermore, we provide UV attenuation coefficients for both near? and offshore sites in the Gulf of Mexico. These estimates are specific to the time and location of the spill, and fall within the range of intensities utilized during photo-induced toxicity tests performed in support of the Deepwater Horizon Natural Resource Damage Assessment (NRDA). These data further validate the methodologies and findings of phototoxicity tests included in the Deepwater Horizon NRDA, while underscoring the importance of considering UV exposure when assessing possible risks following oil spills.Bristow, T.F., Rampe, E.B., Achilles, C.N., Blake, D.F., Chipera, S.J., Craig, P., Crisp, J.A., Des Marais, D.J., Downs, R.T., Gellert, R., Grotzinger, J.P., Gupta, S., Hazen, R.M., Horgan, B., Hogancamp, J.V., Mangold, N., Mahaffy, P.R., McAdam, A.C., Ming, D.W., Morookian, J.M., Morris, R.V., Morrison, S.M., Treiman, A.H., Vaniman, D.T., Vasavada, A.R., Yen, A.S., 2018. Clay mineral diversity and abundance in sedimentary rocks of Gale crater, Mars. Science Advances 4, Article eaar3330. minerals provide indicators of the evolution of aqueous conditions and possible habitats for life on ancient Mars. Analyses by the Mars Science Laboratory rover Curiosity show that ~3.5–billion year (Ga) fluvio-lacustrine mudstones in Gale crater contain up to ~28 weight % (wt %) clay minerals. We demonstrate that the species of clay minerals deduced from x-ray diffraction and evolved gas analysis show a strong paleoenvironmental dependency. While perennial lake mudstones are characterized by Fe-saponite, we find that stratigraphic intervals associated with episodic lake drying contain Al-rich, Fe3+-bearing dioctahedral smectite, with minor (3 wt %) quantities of ferripyrophyllite, interpreted as wind-blown detritus, found in candidate aeolian deposits. Our results suggest that dioctahedral smectite formed via near-surface chemical weathering driven by fluctuations in lake level and atmospheric infiltration, a process leading to the redistribution of nutrients and potentially influencing the cycling of gases that help regulate climate.Broda, M., Majka, J., Olek, W., Mazela, B., 2018. Dimensional stability and hygroscopic properties of waterlogged archaeological wood treated with alkoxysilanes. International Biodeterioration & Biodegradation 133, 34-41. waterlogged elm wood was treated with methyltrimethoxysilane (MTMS) and (3-mercaptopropyl)trimethoxysilane (MPTES), respectively, and anti-shrink efficiency and sorption properties of the impregnated wood samples were determined. The applied impregnants stabilized wood dimensions efficiently enough, i.e. the obtained anti-shrink efficiency was 81 and 98% for MTMS- and MPTES-treated wood, respectively. Both alkoxysilanes can be considered as potential new consolidants. Hygroscopic properties of untreated and impregnated wood were investigated with the DVS experiments. The application of MTMS and MPTES reduced wood equilibrium moisture content (EMC) and sorption hysteresis e.g. hysteresis relative change was ?83.7 and ?73.7% for MTMS- and MPTES-treated wood, respectively. The EMC reduction was observed in the whole hygroscopic range and it was primary due to the monolayer capacity decrease to 50 and 30% of the value for untreated wood and observed for adsorption and desorption modes, respectively. The DVS experiments revealed chemical instability of the MTMS-wood system which was neutralized after the cyclic sorption. The possible scenarios of the interaction of both alkoxysilanes with wood structure were discussed.Brook, E.J., Buizert, C., 2018. Antarctic and global climate history viewed from ice cores. Nature 558, 200-208. growing network of ice cores reveals the past 800,000 years of Antarctic climate and atmospheric composition. The data show tight links among greenhouse gases, aerosols and global climate on many timescales, demonstrate connections between Antarctica and distant locations, and reveal the extraordinary differences between the composition of our present atmosphere and its natural range of variability as revealed in the ice core record. Further coring in extremely challenging locations is now being planned, with the goal of finding older ice and resolving the mechanisms underlying the shift of glacial cycles from 40,000-year to 100,000-year cycles about a million years ago, one of the great mysteries of climate science.Brookfield, M.E., Stebbins, A.G., Rampino, M.R., Hannigan, R.E., 2018. Significance of carbon, nitrogen and their isotopic changes in a Permian-Triassic non-marine boundary section at Carlton Heights (Karoo Basin), South Africa. Journal of African Earth Sciences 145, 170-177. performed analyses of Corg, Norg, δ13Corg, and δ15Norg from the non-marine Permian-Triassic boundary section at Carlton Heights in the Karoo Basin, South Africa. The Carlton Heights section is thus far unique in the Karoo in containing the Permian-Triassic palynological boundary between the Upper Permian Klausipollenites schaubergeri Zone and the Lower Triassic Kraeuselisporites-Lunatisporites Zone, separated by a 1-m thick “fungal event” zone, marked by abundant fungal cell remains (Reduviasporonites) and woody debris. The Corg values obtained are very low (below 0.05%), but reach a maximum of 0.1% in the middle of the fungal event zone. Norg varies little from 0.02%, except in the middle and top of the fungal event, where it rises to 0.04%. C/N ratios are extremely low throughout the section (less than 3), reaching a maximum of 2.49 during the fungal event, coincident with the peaks in Norg and Corg. The very low C/N ratios resemble those found in modern burned soils with low bacteria/fungi ratios, and the lack of variation suggests no change in the organic matter source. δ15Norg values vary between 2.46‰ and 4.25‰, showing no significant changes in the fungal event zone. The δ13Corg values are all below ?25‰, and reach a low of ?27.41‰ in the fungal event zone. This negative shift in δ13Corg is an example of the global negative shift in δ13C found associated with the end-Permian extinctions and fungal event.Bruger, E.L., Marx, C.J., 2018. A decade of genome sequencing has revolutionized studies of experimental evolution. Current Opinion in Microbiology 45, 149-155. sequencing has revolutionized studies using experimental evolution of microbes because it readily provides comprehensive insight into the genetic bases of adaptation. In this perspective we discuss applications of sequencing-based technologies used to study evolution in microbes, including genomic sequencing of isolated evolved clones and mixed evolved populations, and also the use of sequencing methods to follow the fate of introduced variations, whether neutral barcodes or variants introduced by genome editing. Collectively, these sequencing-based approaches have vastly advanced the examination of evolution in the lab, as well as begun to synthesize this work with examination of the genetic bases of adaptation and evolutionary dynamics within natural populations.Brügger, B., 2018. Inconspicuous little allies: How membrane lipids help modulate protein function. ACS Central Science 4, 530-531. molecular-level insight into the lipid binding to membrane proteins and how it induces a protein’s conformational change.Brzozowska, I., Bogdanowicz, A., Szcz?sny, P., Zielenkiewicz, U., Laudy, A., 2018. Evaluation of bacterial diversity on historical silk velvet textiles from the Museum of King John III's Palace at Wilanów, Poland. International Biodeterioration & Biodegradation 131, 78-87. the diversity and the role of microorganisms residing on an art object is important for its conservation and future preservation. This study reports the first application of a culture-independent NGS approach to identify the total community present on biodeteriorated historical artistic textiles. The samples were taken from five Royal Apartments decorated with Genoa type silk velours and different conservation procedures were applied to their fragments. Sequencing of 16S rRNA amplicons revealed overall high similarity in microbial biodiversity. Interestingly, conservation procedures had little effect on the structure of the microbial population. Similarly, airflow did not appear to influence the biodiversity of microorganisms on the silks, as neighbouring rooms did not exhibit greater similarity in the structure of the population of bacteria, in comparison to remote ones. The high biodiversity found on silks is likely to represent the complex history of the velvets, not the immediate past. Therefore, further studies, relying on techniques for analysis of living microbes, are needed to elucidate the sophisticated process of biodeterioration of museum objects.Bulkan, ?., Yal??n, M.N., Wilkes, H., 2018. Geochemistry of Marmara Lake sediments - Implications for Holocene environmental changes in Western Turkey. Quaternary International 486, 199-214. from the Early Holocene marked environmental changes have been revealed by a multi-proxy study of two radiocarbon-dated sediment cores from Lake Marmara. Both cores are composed of fine clastic sediments deposited over the last 1845 years. The core taken from the western depocentre supplementary consists of a 20?cm thick interval which represents a time period of 10.28 to 8.28ka yrBP. A desiccation event caused 6435 year hiatus in the sedimentary record. The lake was established again at 1.85ka yrBP. After a transitional humid phase at the beginning of the Late Holocene, overall arid conditions were continuously effective.Especially the difference between the geochemical composition of Early and Late Holocene sediments indicates distinctive environmental conditions. Respective humid phases took place in between 10.28 and 8.28ka yrBP (Early Holocene) and 1.85 to 1.72ka yrBP (Late Holocene). The Early Holocene phase is characterized by higher fluvial activity controlled by the humid climate and active tectonics. Right after the Middle Holocene droughts, a short-termed tendency to relatively fresh and oxic conditions prevailed. However, the small surface area of the lake and its shallow conditions caused fast variations of hydrology, oxidation level, salinity and organic productivity during the last 1850 years. We suggest that a combination of the instability of the Eastern Mediterranean climate and local conditions is the main control on the changing paleo-environment during the study period.Burgener, L.K., Huntington, K.W., Sletten, R., Watkins, J.M., Quade, J., Hallet, B., 2018. Clumped isotope constraints on equilibrium carbonate formation and kinetic isotope effects in freezing soils. Geochimica et Cosmochimica Acta 235, 402-430. clumped and stable isotope (Δ47, δ18O, and δ13C) composition of pedogenic (soil) carbonates from cold, arid environments may be a valuable paleoclimate archive for climate change-sensitive areas at high latitudes or elevations. However, previous work suggests that the isotopic composition of cold-climate soil carbonates is susceptible to kinetic isotope effects (KIE). To evaluate the conditions under which KIE occur in cold-climate soil carbonates, we examine the Δ47, δ18O, and δ13C composition of soil carbonate pendants from Antarctica (Dry Valleys, 77°S), the High Arctic (Svalbard 79°N), the Chilean and Argentinian Andes, and the Tibetan plateau (3800–4800?m), and compare the results to local climate and water δ18O records. At each site we calculate the expected equilibrium soil carbonate Δ47 and δ18O values and estimate carbonate Δ47 and δ18O anomalies (observed Δ47 or δ18O minus the expected equilibrium Δ47 or δ18O). Additionally, we compare the measured carbonate δ13C to the expected range of equilibrium soil carbonate δ13C values. To provide context for interpreting the Δ47 and δ18O anomalies, the soil carbonate results are compared to results for sub-glacial carbonates from two different sites, which exhibit large Δ47 anomalies (up to ?0.29‰). The Antarctic and 4700 masl Chilean Andes samples have negative Δ47 anomalies and positive δ18O anomalies consistent with KIE due to rapid bicarbonate dehydration during cryogenic carbonate formation. In contrast, the lower elevation Chilean Andes, Argentinian Andes, Tibetan Plateau and High Arctic results are consistent with equilibrium, summer carbonate formation. We attribute the differences in Δ47 and δ18O anomalies to variations in inter-cobble matrix grain size and its effects on the effective soil pore space, permeability (hydraulic conductivity), moisture, and bicarbonate dehydration rate. The Antarctic and 4700 masl Chilean Andean soils have coarse-grained matrices that facilitate rapid bicarbonate dehydration. In contrast, the lower elevation Chilean Andes, Argentinian Andes, High Arctic and Tibetan Plateau soils have finer-grained matrices that decrease the soil pore space, soil permeability and CO2 gas flux, promoting equilibrium carbonate formation. The sub-glacial carbonate samples yield highly variable Δ47 and δ18O anomalies, and we propose that the differences between the two glacier sites may be due to variations in local sub-glacial drainage conditions, pCO2, and pH. Our findings suggest that carbonates from soils with coarse-grained matrices may exhibit KIE in cold climates, making them poor paleoclimate proxies. Soils with fine-grained matrices are more likely to yield equilibrium carbonates suitable for paleoclimate reconstructions regardless of climate. Paleosol matrix grain size should therefore be taken into account in the evaluation of carbonate stable and clumped isotope values in paleoclimate studies.Burke, A., Present, T.M., Paris, G., Rae, E.C.M., Sandilands, B.H., Gaillardet, J., Peucker-Ehrenbrink, B., Fischer, W.W., McClelland, J.W., Spencer, R.G.M., Voss, B.M., Adkins, J.F., 2018. Sulfur isotopes in rivers: Insights into global weathering budgets, pyrite oxidation, and the modern sulfur cycle. Earth and Planetary Science Letters 496, 168-177. biogeochemical sulfur cycle is intimately linked to the cycles of carbon, iron, and oxygen, and plays an important role in global climate via weathering reactions and aerosols. However, many aspects of the modern budget of the global sulfur cycle are not fully understood. We present new δ34S measurements on sulfate from more than 160 river samples from different geographical and climatic regions—more than 46% of the world's freshwater flux to the ocean is accounted for in this estimate of the global riverine sulfur isotope budget. These measurements include major rivers and their tributaries, as well as time series, and are combined with previously published data to estimate the modern flux-weighted global riverine δ34S as 4.4 ± 4.5‰ (V-CDT), and 4.8 ± 4.9‰ when the most polluted rivers are excluded. The sulfur isotope data, when combined with major anion and cation concentrations, allow us to tease apart the relative contributions of different processes to the modern riverine sulfur budget, resulting in new estimates of the flux of riverine sulfate due to the oxidative weathering of pyrites (1.3 ± 0.2 Tmol S/y) and the weathering of sedimentary sulfate minerals (1.5 ± 0.2 Tmol S/y). These data indicate that previous estimates of the global oxidative weathering of pyrite have been too low by a factor of two. As pyrite oxidation coupled to carbonate weathering can act as a source of CO2 to the atmosphere, this global pyrite weathering budget implies that the global CO2 weathering sink is overestimated. Furthermore, the large range of sulfur isotope ratios in modern rivers indicates that secular changes in the lithologies exposed to weathering through time could play a major role in driving past variations in the δ34S value of seawater.Bushnev, D.A., Burdelnaya, N.S., Goncharov, I.V., Samoylenko, V.V., Veklich, M.A., 2018. Comparison of organic matter from Upper Jurassic oil shale of the East European Platform and the Bazhenov Formation by molecular and isotopic data. Doklady Earth Sciences 480, 611-614. molecular and isotopic composition of an extract from the rocks of the Bazhenov Formation in the southeast part of Western Siberia, oils that are genetically related to this formation, and products of hydrous pyrolysis of the organic matter of oil shale (Middle Volgian) of the East European Platform were studied. Common features and differences in their molecular composition were shown. The carbon isotope composition for C14–C30 n-alkanes was determined for the first time; a negative isotope anomaly was revealed for C26 n-alkane in all samples studied. It was concluded that in spite of the geographical distance, specific biota was revealed in the Volga Basin. This biota conditioned an isotopic indicator, which is genetically significant. Original Russian Text ? D.A. Bushnev, N.S. Burdelnaya, I.V. Goncharov, V.V. Samoylenko, M.A. Veklich, 2018, published in Doklady Akademii Nauk, 2018, Vol. 480, No. 2, pp. 195–199.Calvano, C.D., Monopoli, A., Cataldi, T.R.I., Palmisano, F., 2018. MALDI matrices for low molecular weight compounds: an endless story? Analytical and Bioanalytical Chemistry 410, 4015-4038. its introduction in the 1980s, matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) has gained a prominent role in the analysis of high molecular weight biomolecules such as proteins, peptides, oligonucleotides, and polysaccharides. Its application to low molecular weight compounds has remained for long time challenging due to the spectral interferences produced by conventional organic matrices in the low m/z window. To overcome this problem, specific sample preparation such as analyte/matrix derivatization, addition of dopants, or sophisticated deposition technique especially useful for imaging experiments, have been proposed. Alternative approaches based on second generation (rationally designed) organic matrices, ionic liquids, and inorganic matrices, including metallic nanoparticles, have been the object of intense and continuous research efforts. Definite evidences are now provided that MALDI MS represents a powerful and invaluable analytical tool also for small molecules, including their quantification, thus opening new, exciting applications in metabolomics and imaging mass spectrometry. This review is intended to offer a concise critical overview of the most recent achievements about MALDI matrices capable of specifically address the challenging issue of small molecules analysis.Cao, G., Lin, M., Jiang, W., Zhao, W., Ji, L., Li, C., Lei, D., 2018. A statistical-coupled model for organic-rich shale gas transport. Journal of Petroleum Science and Engineering 169, 167-183. of shale permeability is challenging owing to the complicated physics of gas flow and the small-scale heterogeneity in nanometer pores. In this study, a statistical-coupled model (SCM), based on the combination of FIB/SEM and SEM imaging measurements and statistical analysis is proposed to bridge the nanopore-scale with the organic representative elementary volume (oREV)-scale. FIB/SEM imaging is adopted to get the nanometer pores properties in organic matter (OM), and SEM imaging is used to get the OM content distribution. With the analysis of nanopores of a Longmaxi shale sample from the Chongqing Province, China, it is demonstrated that the pore size distribution obtained from FIB/SEM images of typical samples is representative considering the principal parts of the pore radii are similar comparing with 2D SEM image. Then, the SCM is constructed based on the combination of the statistical method, the series-parallel model and the equivalent model for microstructures, and the rationality of SCM are also investigated. The obtained characteristic parameters show an excellent performance in calculating the SCM element permeability with a small deviation of less than 3% and a significantly faster computation speed comparing with the previous literature by approximately 400 times. Using the SCM, a method for the construction of oREV and the determination of oREV-scale permeability for the organic-rich shale is presented. Finally, the sensitivity analyses of oREV-scale permeability are conducted and the results show that the permeability is sensitive to the OM content distribution, the district of shale sample and the permeability of IOM. The influence of OM permeability on macroscale is also analyzed. The new model can advance the understanding of the multiscale phenomena and establish a relationship between microscale properties and macroscale behavior.Cao, M., Rueda, G., Rivas-Ruiz, P., Trapote, M.C., Henriksen, M., Vegas-Vilarrúbia, T., Rosell-Melé, A., 2018. Branched GDGT variability in sediments and soils from catchments with marked temperature seasonality. Organic Geochemistry 122, 98-114. distributions of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in sediments are used as a proxy measurement to infer changes in past mean annual air temperatures (MAT). When applied to high resolution sedimentary sequences, measurement of brGDGT distributions is employed to reconstruct MAT at subdecadal time scales. In addition, brGDGT proxy estimates are also sometimes purported to be seasonally biased in environments where annual brGDGT production may not be constant during a seasonal cycle. The main aim of this study was to assess the occurrence of seasonality in the production and distribution of brGDGTs and the seasonality bias of the derived temperature proxy. For this purpose, we examined brGDGT distributions and brGDGT-derived MAT estimates in surface soils and settling/suspended particulate matter over one year, from two sites located in the same latitude but at different altitudes, in the Catalan Pyrenees, as well as at one site in southern Norway. These locations have marked seasonal temperature cycles, which were expected to maximize the possibility of detecting any seasonal bias in the production and compositions of brGDGTs. The results show that brGDGT abundance is heterogeneous and increases with soil humidity. The brGDGT distributions and some of the brGDGT-derived proxy measurements in soils are relatively stable throughout the year and do not change significantly in the suspended particulate matter in the river or settling particulate matter in traps. Our study shows that the impact of the seasonality of temperature on brGDGT distribution was absent in the soils studied, regardless of altitude or latitude on a catchment/regional scale. As soils are likely to contain a brGDGT signature which is representative of average environmental conditions in the catchment at least over decades, brGDGT proxy reconstructions derived from soil sources are more suitable to infer variability in environmental parameters over the same timescales (i.e. decades or longer). On shorter timescales (i.e. annual), sediment downcore variability in brGDGTs is likely to be related to changes derived from in situ production and sediment sources.Cappellini, E., Prohaska, A., Racimo, F., Welker, F., Pedersen, M.W., Allentoft, M.E., de Barros Damgaard, P., Gutenbrunner, P., Dunne, J., Hammann, S., Roffet-Salque, M., Ilardo, M., Moreno-Mayar, J.V., Wang, Y., Sikora, M., Vinner, L., Cox, J., Evershed, R.P., Willerslev, E., 2018. Ancient biomolecules and evolutionary inference. Annual Review of Biochemistry 87, 1029-1060. the past three decades, studies of ancient biomolecules -particularly ancient DNA, proteins, and lipids - have revolutionized our understanding of evolutionary history. Though initially fraught with many challenges, today the field stands on firm foundations. Researchers now successfully retrieve nucleotide and amino acid sequences, as well as lipid signatures, from progressively older samples, originating from geographic areas and depositional environments that, until recently, were regarded as hostile to long-term preservation of biomolecules. Sampling frequencies and the spatial and temporal scope of studies have also increased markedly, and with them the size and quality of the data sets generated. This progress has been made possible by continuous technical innovations in analytical methods, enhanced criteria for the selection of ancient samples, integrated experimental methods, and advanced computational approaches. Here, we discuss the history and current state of ancient biomolecule research, its applications to evolutionary inference, and future directions for this young and exciting field.Catling, D.C., Krissansen-Totton, J., Kiang, N.Y., Crisp, D., Robinson, T.D., DasSarma, S., Rushby, A.J., Del Genio, A., Bains, W., Domagal-Goldman, S., 2018. Exoplanet biosignatures: A framework for their assessment. Astrobiology 18, 709-738. life on exoplanets from telescopic observations is an ultimate goal of exoplanet science. Life produces gases and other substances, such as pigments, which can have distinct spectral or photometric signatures. Whether or not life is found with future data must be expressed with probabilities, requiring a framework of biosignature assessment. We present a framework in which we advocate using biogeochemical “Exo-Earth System” models to simulate potential biosignatures in spectra or photometry. Given actual observations, simulations are used to find the Bayesian likelihoods of those data occurring for scenarios with and without life. The latter includes “false positives” wherein abiotic sources mimic biosignatures. Prior knowledge of factors influencing planetary inhabitation, including previous observations, is combined with the likelihoods to give the Bayesian posterior probability of life existing on a given exoplanet. Four components of observation and analysis are necessary. (1) Characterization of stellar (e.g., age and spectrum) and exoplanetary system properties, including “external” exoplanet parameters (e.g., mass and radius), to determine an exoplanet's suitability for life. (2) Characterization of “internal” exoplanet parameters (e.g., climate) to evaluate habitability. (3) Assessment of potential biosignatures within the environmental context (components 1–2), including corroborating evidence. (4) Exclusion of false positives. We propose that resulting posterior Bayesian probabilities of life's existence map to five confidence levels, ranging from “very likely” (90–100%) to “very unlikely” (<10%) inhabited.Chandan, D., Peltier, W.R., 2018. On the mechanisms of warming the mid-Pliocene and the inference of a hierarchy of climate sensitivities with relevance to the understanding of climate futures. Climate of the Past 14, 825-856. present results from our investigation into the physical mechanisms through which the mid-Pliocene, with a pCO2 of only ?～??400?ppmv, could have supported the same magnitude of global warmth as has been projected for the climate at the end of the 21st century when pCO2 is expected to be 3 times higher. These mechanisms allow us to understand the warming in terms of changes to the radiative properties of the surface, the clouds, greenhouse gases, and changes to the meridional heat transport. We find that two-thirds of the warming pervasive during the mid-Pliocene, compared to the preindustrial, could be attributed to the reduction in the planetary emissivity owing to the higher concentrations of the greenhouse gases CO2 and water vapor, and the remaining one-third to the reduction in planetary albedo. We also find that changes to the orography and the pCO2 are the leading causes of the warming with each contributing in roughly equal parts to a total of 87?% of the warming and changes to the polar ice sheets responsible for the remaining warming. Furthermore, we provide a mid-Pliocene perspective on ongoing efforts to understand the climate system's sensitivity at various timescales and using multiple lines of evidence. The similarities in the boundary conditions between the mid-Pliocene and the present day, together with the globally elevated temperatures, make the mid-Pliocene an ideal paleo time period from which to derive inferences of climate sensitivity and assess the impacts of various timescale-dependent feedback processes. We assess a hierarchy of climate sensitivities of increasing complexity in order to explore the response of the climate over a very large range of timescales. The picture that emerges is as follows: on the short timescale, owing to the influence of fast feedback processes, the climate sensitivity is 3.25?°C per doubling of CO2; sensitivity increases to 4.16?°C per doubling of CO2 on an intermediate timescale as the ice–albedo feedback becomes active, and then sensitivity further increases to 7.0?°C per doubling of CO2 on long timescales due to the feedback from the glacial isostatic adjustment of the Earth's surface in response to the melting of the polar ice sheets. Finally, once the slow feedbacks have stabilized, the sensitivity of the system drops to 3.35?°C per doubling of CO2. Our inference of the intermediate-timescale climate sensitivity suggests that the projected warming by 2300?CE, inferred using Earth system models of intermediate complexity on the basis of an extension to the RCP4.5 emission scenario in which atmospheric pCO2 stabilizes at roughly twice the PI level in year 2150?CE, could be underestimated by ?～?1?°C due to the absence of ice-sheet-based feedbacks in those models.Chandrasekharan Nair, V., Mech, D., Gupta, P., Sangwai, J.S., 2018. Polymer flooding in artificial hydrate bearing sediments for methane gas recovery. Energy & Fuels 32, 6657-6668. flooding has been one of the most promising methods used for enhanced oil recovery from matured crude oil reservoirs across the globe due to its distinct advantages over simple water flooding. However, the use of polymer flooding has not yet been investigated for methane recovery from hydrate reservoirs. In our earlier work, we have investigated the effect of various molecular weights and concentrations of polyethylene glycol (PEG) polymer on the phase stability and kinetics of methane hydrate. This information has been explored for successful use of PEG as a chemical agent for polymer flooding from hydrate reservoirs. In this work, detailed experimental investigations on methane production from hydrate bearing sediments have been carried out using PEG polymer flooding in a three-dimensional hydrate reactor. Initially, methane hydrate formation has been investigated using two silica sand porous beds (viz., 0.16 and 0.46 mm), and pure water at an initial hydrate formation pressure of 8 MPa and 277.15 K. Subsequently, hydrate dissociation studies have been carried out using polymer flooding at a final hydrate reservoir pressure of ～4.3 MPa and 277.15 K. The effect of molecular weights (200 and 600 kg/kmol, viz., PEG-200 and PEG-600, respectively), concentrations (0.2 and 0.4 mass fractions), and injection rates (1 and 5 mL/min) of PEG aqueous solution has been analyzed for methane gas recovery. PEG-200 is observed to be an effective flooding agent as compared to PEG-600 and other inhibitor such as ethylene glycol used in the literature. In addition, studies on the total dissolved solids (TDS) and electrical conductivity of PEG aqueous solutions have also been investigated before and after flooding to check the efficacy of polymer flooding for methane production. PEG has a much lower freezing point (208.15 K, i.e., ?65 °C) compared to ethylene glycol (260.25 K, i.e., ?12.9 °C); therefore, polymer flooding is expected to be more beneficial for methane gas production from hydrate bearing zones with low reservoir temperatures.Chandru, K., Guttenberg, N., Giri, C., Hongo, Y., Butch, C., Mamajanov, I., Cleaves, H.J., 2018. Simple prebiotic synthesis of high diversity dynamic combinatorial polyester libraries. Communications Chemistry 1, Article 30. is widely believed that the origin of life depended on environmentally driven complexification of abiotically produced organic compounds. Polymerization is one type of such complexification, and it may be important that many diverse polymer sequences be produced for the sake of selection. Not all compound classes are easily polymerized under the environmental conditions present on primitive planets, and it is possible that life’s origin was aided by other monomers besides those used in contemporary biochemistry. Here we show that alpha-hydroxy acids, which are plausibly abundant prebiotic monomers, can be oligomerized to generate vast, likely sequence-complete libraries, which are also stable for significant amounts of time. This occurs over a variety of reaction conditions (temperature, concentration, salinity, and presence of congeners) compatible with geochemical settings on the primitive Earth and other solar system environments. The high-sequence heterogeneity achievable with these compounds may be useful for scaffolding the origin of life.Chang, H., Chu, X., Feng, L., Huang, J., Chen, Y., 2018. Marine redox stratification on the earliest Cambrian (ca. 542–529?Ma) Yangtze Platform. Palaeogeography, Palaeoclimatology, Palaeoecology 504, 75-85. order to explore the marine redox structure on the earliest Cambrian (ca. 542–529?Ma) Yangtze Platform, South China, new Fe-Mo-C-S geochemical data from the slope Xugongping section for the Liuchapo and the base of Niutitang Formation are reported here. Integrated Fe speciation and Mo abundance data from the Xugongping section, in combination with previously published data from slope-basinal Longbizui section and others, suggest oxic surface waters and ferruginous deep waters coexisting with occasional mid-depth euxinic waters during the Fortunian Stage, and with widespread euxinic waters during the early Stage 2 marine transgression. A compilation of new and published sulfur isotope data of pyrite for the Liuchapo and the base of Niutitang Formations presents high isotopic values (mostly >+10‰) and distinctly different spatiotemporal gradient characteristics during the Fortunian Stage and the beginning of the Stage 2. We propose that redox stratification developed in the earliest Cambrian protected basin, and eustatic change and the connectivity of the protected basin with the open ocean controlled the materials supply from riverine input and open ocean reservoir and thus spatiotemporal variability of ocean Chaturvedi, E., Prasad, N., Mandal, A., 2018. Enhanced formation of methane hydrate using a novel synthesized anionic surfactant for application in storage and transportation of natural gas. Journal of Natural Gas Science and Engineering 56, 246-257. and transportation of natural gas in the form of hydrate attract interest in recent times as a huge amount of gas can be accumulated within a small volume of solid hydrate. In the present study, a novel surfactant synthesized from castor oil is used as gas hydrate promoter with a significant increase in formation rate, reduction of induction time and higher gas storage capacity, which is desirable for storage and transportation of natural gas in the form of hydrate. The study includes characterization of the synthesized natural surfactant and its effect on storage capacity, kinetics, and rate of formation of hydrate at different concentrations. A higher storage capacity of 96% of the theoretical maximum value was obtained for the system with 9000?ppm concentration of the surfactant. Hydrate formation follows first-order kinetics with a higher kinetic rate at higher concentration of surfactant. This indicates feasibility to use the naturally derived surfactant to increase the storage capacity and transportation efficiency of natural gas.Chen, H., Qin, Y., Tian, W., Geng, M., Li, G., Chen, Z., Deng, Z., Sang, G., Xia, D., 2018. Factors influencing the biogenic gas production of low rank coal beds in the Jiergalangtu sag, Erlian Basin. Natural Gas Industry 38, 27-32. study on the factors influencing the biogenic gas production of low rank coal beds is of great significance to the search of the favorable biogas enrichment areas of similar coal beds and the guidance of the microbial stimulation technologies. In this paper, the lignite samples taken from the Jiergalangtu sag in the Erlian Basin were selected to carry out the simulation experiment of biogenic coalbed methane under different temperatures, pH values, oxidation-reduction potentials (Eh) and trace element concentrations. Then, the influences on biogenic gas production were discussed and the optimal biogenic gas production condition was determined. And the following research results were obtained. First, in the simulation experiments, the biogas production of coal beds increases first and then decreases with the increase of temperature, pH and trace element concentration and the decrease of Eh. Second, in the case of temperature 30-35 ℃, pH 7.0-7.5 and Eh –225 mV, the metabolism of methanogen is the most active and the most favorable for the generation of biogas, so biogenic gas production can be promoted by adding the trace elements (Fe2+ and Ni2+) of proper concentration. It is concluded that a proper burial depth (300–600 m), a weak runoff hydrodynamic condition and an anaerobic environment constitute the favorable conditions for the generation of biogas in the Jiergalangtu sag, Erlian Basin. Moreover, the addition of appropriate trace elements can be an effective means of microbial stimulation.Chen, J., He, L., Luo, X., Zhang, C., 2018. Foaming of crude oil: Effect of acidic components and saturation gas. Colloids and Surfaces A: Physicochemical and Engineering Aspects 553, 432-438. tendency of crude oil is diverse due to the variance in crude oil components. Crude oil viscosity, asphaltene, and resin contents have been studied in general, but the specific surfactant molecules that stabilize crude oil foam are not identified. Carbon dioxide oftentimes accompanies hydrocarbon gases in reservoirs rich in natural CO2 and fields where CO2 enhanced recovery is implemented. Crude oil acidic components and carbon dioxide may have considerable significance to foam formation and defoaming kinetics. We studied the effect of acidic components and saturation gas on foaming of crude oils with pneumatic and depressurization tests respectively. Foaminess, foamability and time to half collapse are used to characterize foaming of oils. We present a new piecewise model that can be divided into two segments with almost equal timescales to fit the collapse curve and we use parabola function and expdec1 function to model the two segments respectively. The t values at the intersection of two segments are approximately the same as time to half collapse. Model parameter A is close to foamability. Increase in the rigidity of the interface and viscosity of the bulk liquid may account for excellent foam stability of some acids/oil systems. Some acidic crude oil components, for example, naphthenic acids, long-chain fatty acids, increase foaminess significantly, suggesting that crude oil antifoams combined with reagents that will react with some acidic components may have better performance.Chen, J., Li, W., Ni, Y., Dai, X., Liang, D., Deng, C., Bian, L., 2018. The Permian source rocks and their natural gas prospects in the Sichuan Basin (II): The geochemical characteristics of source rocks and the potential of natural gas resource. Natural Gas Industry 38, 33-45. are two sets of source rocks in the Permian of the Sichuan Basin, i.e., the Middle Permian marine carbonate rocks and the Upper Permian transitional clastic rocks. Since the Permian source rocks are currently at the over-mature stage, there is no clear understanding of their original hydrocarbon generation potential and natural gas resource potential. In this paper, the geochemical characteristics and the relationship between hydrocarbon generation potential and maturity of abundant Permian source rock samples taken from the exploration wells in the Sichuan Basin and its peripheral sections were investigated. Then, the original hydrocarbon generation potential of Permian source rocks, the hydrocarbon generation and expulsion during geological history and the resource potential of natural gas from kerogen and crude oil cracking were discussed. And the following research results were obtained. First, mudstone and carbonaceous mudstone in the Upper Permian Longtan Fm are characterized by high organic matter abundance and great hydrocarbon generation potential, and they are the most important source rocks in the Permian. Coal in the Longtan Fm is also very important gas source rocks. The Dalong Fm of Upper Permian is also very high in TOC and hydrocarbon generation potential, and it is the important source rock in the northern part of the basin. While the Middle Permian carbonate source rocks are the secondary source rocks with low organic matter abundance and initial hydrocarbon generation potential. Second, the Permian source rocks generated 3 290×108 t crude oil and 420×1012 m3 natural gas during the geological history, in which the contribution of Longtan Fm source rocks to crude oil and natural gas is 80% and 85%, respectively. Third, the crude oil resources of paleo-oil reservoirs derived from the Permian source rocks are as high as 580×108 t, and the total natural gas resources are up to 6.55×1012 m3, including 4.45×1012 m3 (70%) oil-cracking gas and 2.10×1012 m3 natural gas directly generated from kerogen. It is concluded that the northern and central–southeastern parts of the basin are the two hydrocarbon generation centers of the Permian and they are the favorable areas of Permian hydrocarbon accumulation and natural gas exploration. Moreover, the paleo-oil reservoirs in these two areas are the most prospective targets for natural gas exploration in the Sichuan Basin.Chen, J., Wei, J., Ni, Y., Chen, J., Deng, C., Tian, D., Hu, J., Huang, Z., Zhang, D., Han, Y., 2018. Geochemical features and maturity classification of crude oil in the Jiuxi depression, Jiuquan Basin. Acta Petrolei Sinica 39, 491-503. depression in Jiuquan Basin is a typical well-explored petroliferous depression, where the crude oil that have been found is mainly distributed in Qingxi sag and the tectonic belt of Yaerxia-Laojunmiao-Shiyougou. The vast majority of crude oil is medium-high waxy crude oil with normal density and viscosity, while only a small amount is medium-high waxy heavy oil, and all is characterized by the geochemical characteristics of typical lacustrine crude oil with the whole-oil carbon isotope δ13C ratio of -32 ‰ to- -30 ‰, overall similar biomarker compositions and distribution characteristics. However, there are some differences, based on which this study has classified three types of crude oil with different categories or maturities. The first type is low-maturity crude oil, of which the steranes are dominated by regular steranes and no diasterane exists. Regular steranes mainly consist of ααα-20R steranes, and C27, C28 and C29 steranes show asymmetric V-type distribution; the 20S/(20S+20R)and ββ/(αα+ββ) ratios of C29 sterane are generally less than 0.4. Terpanes are mainly composed of pentacyclic terpanes with low contents of Ts, C29Ts and C30 diahopane and high content of gammacerane. The second type is generally characterized by medium maturity, of which Pr/Ph value is generally less than 1.0. The steranes are also dominated by regular steranes; no diasterane is found. But ααα-20S and αββ steranes are significantly higher as compared with the first type of crude oil, and the 20S/(20S+20R)and ββ/(αα+ββ) ratios of C29 steranes generally range from 0.40 to 0.55. The ααα-20R C27, C28 and C29 steranes show an asymmetric V-type distribution, and the C27/C29 ratio is generally greater than 0.6; terpanes present the similar distribution with the first type of crude oil; the Ts/Tm ratio is generally less than 0.5. The sterane/terpane ratio is essentially above 1.0. The third type is generally high-maturity crude oil, of which the Pr/Ph value is generally greater than 1.0. The steranes are dominated by regular steranes, but apparently contain diasteranes with great changes in content. The αββ steranes are significantly higher than ααα steranes, and the 20S/(20S+20R)and ββ/(αα+ββ) ratios of C29 steranes are greater than 0.5 and 0.6 respectively. The C29 sterane content is significantly higher than the C27 sterane, while the C27/C29 ratio is generally less than 0.6. This type of crude oil has similar distribution of terpanes with the former two types, the Ts, C29Ts and C30 diahopanes have higher contents, and the Ts/Tm is generally greater than 0.5; the content of gammacerane changes greatly; the sterane/terpane ratio is basically below 1.0.Chen, K., Zhang, T., Chen, X., He, Y., Liang, X., 2018. Model construction of micro-pores in shale: A case study of Silurian Longmaxi Formation shale in Dianqianbei area, SW China. Petroleum Exploration and Development 45, 412-421. on scanning electron microscopy and nitrogen adsorption experiment at low temperature, the pore types and structures of the Longmaxi Formation shale in the Dianqianbei area, SW China were analyzed, and a molecular model was built. According to mathematical statistics, the validation of the model was solved by converting it into a mathematical formula. It is found by SEM that the pores in clay mineral layers and organic pores occupy most of the pores in shale; the nitrogen adsorption experiment at low temperature reveals that groove pores formed by flaky particles and micro-pores are the main types of pores, and the results of the two are in good agreement. A molecular model was established by illite and graphene molecular structures. Moreover, based on the fractal theory and the Frenkel-Halsey-Hill formula, a modified Frenkel-Halsey-Hill formula was proposed. The reliability of the molecular model was verified to some extent by obtaining parameters such as the fractal dimension, replacement rate and fractal coefficients of correction, and mathematical calculation. This study provides the theoretical basis for quantitative study of shale reservoirs.Chen, M.-y., Cheng, Y.-p., Li, H.-r., Wang, L., Jin, K., Dong, J., 2018. Impact of inherent moisture on the methane adsorption characteristics of coals with various degrees of metamorphism. Journal of Natural Gas Science and Engineering 55, 312-320. and water coexist in coal reservoirs. Many scholars have examined the effect of moisture on the gas adsorption property of coal. In this paper, the oxygen-containing functional groups and pore characteristics of five coal samples with different degrees of metamorphism were studied by Fourier transform infrared (FTIR) spectroscopy and CO2 adsorption method, and methane adsorption tests were carried out on coal samples with different inherent moisture contents. The water-holding capacities of different rank coals are related to their oxygen-containing functional groups and micropores characteristics, and the former play a decisive role. This is probably the main reason why low rank coals have stronger water-holding capacity than medium and high rank coals. The Langmuir volume tends to decrease with increasing inherent moisture content for all of the samples, which can be attributed to hydrogen bonding between the coal macromolecules and water molecules. The relationship between the amount of adsorbed methane and the inherent moisture content can be characterized well using the linear and exponential models. And it can be found that the moisture effect coefficient is dependent on the coal rank. Further analysis indicates that the influence of inherent moisture on the methane adsorption capacity is more prominent for low rank coals, which is probably due to its greater hydrophilia and water-holding capacity. Whereas, the reduction in methane adsorption capacity is mainly controlled by the pore-blocking effect of adsorbed water for high rank coals, and the extent of the influence of inherent moisture is a little.Chen, M., Jung, J., Lee, Y.K., Hur, J., 2018. Surface accumulation of low molecular weight dissolved organic matter in surface waters and horizontal off-shelf spreading of nutrients and humic-like fluorescence in the Chukchi Sea of the Arctic Ocean. Science of The Total Environment 639, 624-632. regions play unique roles in global overturning circulation, carbon cycling, and climate change. In this study, seawater dissolved organic matter (DOM) was characterized for the Chukchi Sea in the Arctic Ocean in the summer season. The seawater generally contains high concentrations of dissolved organic carbon (DOC, up to 92?μM?C) and tyrosine-like fluorescence (up to 0.21 RU), and it was enriched with heteroatomic molecular formula with nitrogen-containing and sulfur-containing formulas counting 2246 (~41% of total identified molecular formula) and 1838 (~34%), respectively. Significant correlations were observed between salinity and the absorption coefficient at 254?nm, between chlorophyll-a and DOC as well as the tyrosine-like component, C270/302 (Cex/em maxima), and between biological index and two protein-like components, C275/338 and C305/344. A comparison between surface waters and close-to-seafloor deep waters suggested a trend of the accumulation of low molecular weight (LMW) fraction (~54–74%, nominal average molecular weight Mn?<?~350?Da) in the surface waters. Another interesting finding from spatial data was an obvious horizontal off-shelf spreading of nutrients and humic-like fluorescence. This study sheds novel insights of DOM characteristics and dynamics in the highly productive polar sea.Chen, R., Liu, H., Tong, M., Zhao, L., Zhang, P., Liu, D., Yuan, S., 2018. Impact of Fe(II) oxidation in the presence of iron-reducing bacteria on subsequent Fe(III) bio-reduction. Science of The Total Environment 639, 1007-1014. interplay of Fe(II) oxidation and Fe(III) bio-reduction occurs widely in both natural and engineered redox-dynamic systems. This study aimed to unravel the impact of Fe(II) oxidation by O2 in the presence of iron-reducing bacteria on subsequent Fe(III) bio-reduction. Mixed solutions of Fe2+ (0.1–0.5?mM) and Shewanella oneidensis strain MR-1 (MR-1, 2.0?×?107?CFU/mL) at neutral pH were first exposed to laboratory air for Fe(II) oxidation and bacterial inactivation, and then the resultant Fe(III) suspensions were switched to anoxic conditions for bio-reduction by the surviving bacteria. In the oxidation step, the coexisting MR-1 was inactivated by 0.8–1.71 orders of magnitude within 60?min. In the subsequent bio-reduction step, the resultant Fe(III) was bio-reduced by the surviving MR-1. Bio-reduction of the resultant Fe(III) by the surviving MR-1 was 1.8–2.5 times faster than that of the Fe(III) that was produced from Fe2+ oxidation without MR-1 by fresh MR-1 cells at 2.0?×?107?CFU/mL. Although MR-1 inactivation during Fe(II) oxidation may inhibit Fe(III) bio-reduction, the increase in bio-availability of the resultant Fe(III) and the residual reactivity of dead cells led to net enhancement of bio-reduction under the tested conditions. Lepidocrocite was the sole Fe(III) mineral that was produced from Fe2+ oxidation without MR-1, while 19% ferrihydrite was produced from Fe2+ oxidation in the presence of MR-1. The formation of low-crystallinity ferrihydrite accounts for the increase in bio-availability of the Fe(III) minerals. The findings of this study highlight an important but overlooked impact underlying the interplay of Fe(II) oxidation and Fe(III) bio-reduction.Chen, T., Feng, X.-T., Pan, Z., 2018. Experimental study on kinetic swelling of organic-rich shale in CO2, CH4 and N2. Journal of Natural Gas Science and Engineering 55, 406-417. the increasing demand in natural gas and interest in greenhouse gas sequestration, gas transport mechanism and gas-induced deformation of shale have become important research topics. The shale matrix swells after adsorbing gas, which will impact on the gas transport behaviour in shale. In this paper, the kinetic shale swelling and kinetic gas adsorption in different types of gases at various gas pressures under confining pressure of 20?MPa and temperature of 25?°C were investigated. The gases used in the tests were helium, N2, CH4 and CO2. It was found that shale swelling under this experimental conditions has two components: strain caused by poroelasticity and gas adsorption-induced swelling strain. The experimental results show that gas adsorption induced shale swelling and the absolute adsorption amount in different gases are both about one order of magnitude lower than that of coal and are in a trend line with the results of gas adsorption-induced coal swelling, indicating that shale swelling mechanism may be similar to that of coal. The swelling rate of shale has a positive correlation with the mass rate of gas uptake. Moreover the swelling rate of shale in helium is the highest, and that in CO2 is the lowest due to slow gas diffusion caused by larger CO2 adsorption-induced swelling and CO2 phase transition from vapor state to liquid state at the experimental condition in this study. The swelling rate of shale in CH4 and N2 are almost the same. Helium-induced swelling rate increases with gas pressure due to the change of effective stress, while the swelling rates of shale in CH4, N2 and CO2 are positively correlated to the gas pressure in the early stage and negatively correlated in the later stage due to the different adsorbing gas transport mechanism in macropores and micropores. The phase change of CO2 leads to the change in density and viscosity, resulting in the change of kinetic swelling rate. It was also found in this work that the anisotropy ratio for shale swelling decreases in the order of He, N2, CH4 and CO2. Gas adsorption results in a lower anisotropy ratio, which may be related to the more random distribution of the organic matter and clay minerals, where gas adsorption and its induced swelling occur.Chen, x., Xie, X.t., Li, Y., Chen, S., 2018. Investigation of the synergistic effect of alumina nanofluids and surfactant on oil recovery – Interfacial tension, emulsion stability and viscosity reduction of heavy oil. Petroleum Science and Technology 36, 1131-1136. order to understand the synergistic effect of surfactants and nanofluids on enhancing recovery, hydrophilic and hydrophobic alumina nanomaterials were prepared for alumina nanofluids with surfactants. Oil-water interfacial tension and emulsion stability were investigated. The experimental results showed that nanofluids cooperated with surfactants could reduce oil-water interfacial tension in the proper concentration range, Nanoparticles decreased the average size of droplets, and restrained creaming and coalescence, therefore stabilizing the emulsion. The effect of nanofluids on the viscosity of heavy oil was also tested. The results indicated that the viscosity of heavy oil with surfactants was reduced by 42.8% when nanofluids were added at the shear rate of 10 s-1.Chen, Z., Chen, X., Zhou, C., Yuan, X., Xiao, S., 2018. Late Ediacaran trackways produced by bilaterian animals with paired appendages. Science Advances 4, Article eaao6691. trace fossils provide key paleontological evidence for the evolution of early animals and their behaviors. Thus far, however, this fossil record has been limited to simple surface trails and relatively shallow burrows. We report possible trackways, preserved in association with burrows, from the terminal Ediacaran Shibantan Member (ca. 551 to ca. 541 million years ago) in the Yangtze Gorges area of South China. These trace fossils represent the earliest known trackways. They consist of two rows of imprints arranged in poorly organized series or repeated groups. These trackways may have been produced by bilaterian animals with paired appendages, although the phylum-level phylogenetic affinity of the trace makers remains unknown. It is possible that the trackways and associated burrows were produced by the same trace maker, indicating a complex behavior involving both walking and burrowing. Together, these trackways and burrows mark the arrival of a new era characterized by an increasing geobiological footprint of bilaterian animals.Chen, Z., Li, M., Ma, X., Cao, T., Liu, X., Li, Z., Jiang, Q., Wu, S., 2018. Generation kinetics based method for correcting effects of migrated oil on Rock-Eval data – An example from the Eocene Qianjiang Formation, Jianghan Basin, China. International Journal of Coal Geology 195, 84-101. hydrocarbons occur commonly in liquid-rich source rock reservoirs and can distort analytical results of programed pyrolysis. Disregarding the effect may result in unreliable data interpretation and inappropriate hydrocarbon generation kinetics. This paper proposes a method based on kerogen kinetics for characterizing the impacts, estimating the severity and subsequently minimizing the effects by removal of the migrated components from the oil-stained samples through a numerical approach. The restored hydrocarbon pyrograms are then used for recalculation of relevant Rock-Eval parameters and proper construction of generation kinetic models. The proposed methods and workflow were applied to the source rock samples from the Qianjiang Formation, a confined source rock system imbedded in salt layers, where contamination from migrated hydrocarbons is common. An additional Rock-Eval dataset consisting of whole-rock samples and post-solvent extracted replicates was used to validate the methods. The validation results show that the proposed numerical approach is a cost-effective alternative to the traditional laboratory solution.Chen, Z., Wang, T.G., Li, M., Yang, F., Cheng, B., 2018. Biomarker geochemistry of crude oils and Lower Paleozoic source rocks in the Tarim Basin, western China: An oil-source rock correlation study. Marine and Petroleum Geology 96, 94-112. order to select biomarker parameters that have potential to quantitatively distinguish between the Cambrian–Lower Ordovician and Upper Ordovician source rocks in the Tarim Basin with a total organic carbon content >0.5%, 42 Lower Paleozoic shale samples, were collected from a number of wells and outcrops in the Tarim Basin, northwestern China. The biomarkers in the extracts of the source rocks were analyzed by gas chromatography–mass spectrometry. The results show that C23 and C30 were dominant in the tricyclic terpanes and pentacyclic triterpanes, respectively, and C27 and C29 were both dominant in C27–29 steranes of the source rock samples. The distribution of n-alkanes, isoprenoids and terpanes indicate that the source rock samples have been slightly to moderately biodegraded, and they originated from a reducing depositional environment with considerable marine algal input in. Comparatively, Upper Ordovician source rock samples presented lower values of C28/C29 regular steranes and higher values of C29 ααα20S/(20S + 20R) and C29αββ/(αββ+ααα). Abnormally lower values of C29 ααα20S/(20S + 20R) and C29αββ/(αββ+ααα) were observed in the Cambrian–Lower Ordovician strata. The set of data in this study show that homohopane index including C31 homohopane/C30 hopane, C31-35homohopanes/C30hopane, and the ratios related to the triaromatic steroids including C26?20S/C28?20S TAS, C27?20R/C28?20R, (C26?20R + C27?20S)/C28?20S and C28/(C26+C27) TAS, could serve as potential biomarker parameters to distinguish between the two groups of source rocks in the Tarim Basin. The values of those parameters (in above order) in Cambrian–Lower Ordovician source rocks were <0.6, <1.5, >0.3, >0.5, >0.85, and <1.2, respectively, whereas those in Upper Ordovician source rocks were >0.8, >1.9, <0.3, <0.5, <0.85, and >1.2, respectively. The correlation between the source rock samples and 19 oils obtained from the Tadong, Tabei and Tazhong uplifts in the Tarim Basin show that most of the oils in Tabei uplift are probably from Upper Ordovician source rocks, the oils in Tadong uplift are more likely from Cambrian- Lower Ordovician source rocks, and the Tazhong uplift is more like a mixed oil region with oils from both of the two groups of source rocks.Chen, Z., Yang, D., 2018. Quantification of phase behaviour of solvents-heavy oil/bitumen systems in the presence of water at high pressures and elevated temperatures. Fuel 232, 803-816. this work, a new and pragmatic methodology has been developed and validated to predict phase boundaries together with their types as well as solvent solubility for solvents-heavy oil/bitumen-water systems in a temperature range of 298–573?K, for which the measured data are collected from literature. More specifically, two newly modified alpha functions respectively for non-water components and water are incorporated into the Peng-Robinson equation of state (PR EOS). The binary interaction parameters (BIPs) are based on the solubility data of binary mixtures, while new BIP correlations are proposed for toluene-water pair and heavy oil/bitumen-water pairs. The BIPs for heavy oil/bitumen-water pairs (denoted as BIPHO - water) is regressed as a function of the concentration of resin and asphaltene in heavy oil/bitumen. The newly developed model is found to accurately predict the measured ALV/AL and LV/L boundaries (“A” represents the aqueous phase, “L” denotes the oleic phase, and “V” refers to the vapour phase) with an overall AARD of 4.5% and solvent solubility in the oleic phase with an overall AARD of 9.4%, respectively. It is found that addition of water may dramatically affect the phase boundaries of solvents-heavy oil/bitumen mixtures, and thus leads to a significant reduction of solvent solubility in heavy oil/bitumen, depending on solvent type, temperature, and pressure. The water molar fraction in feed plays an important role in influencing the solvent dissolution in heavy oil/bitumen in LV equilibria due to the fact that it affects the partial pressure of the solvent greatly. After adding a certain amount of water for which ALV equilibria is established, solvent dissolution in heavy oil/bitumen will not be affected by water because its subsequent addition in feed does not impose an impact on the partial pressure of the solvent. Since solvent dissolution rate in heavy oil/bitumen can be much higher in ALV equilibria than LV equilibria and a large portion of solvents can be dissolved in heavy oil/bitumen in ALV equilibria in a very narrow pressure range, effects of water must be considered at given conditions. Addition of solvents can enhance the water dissolution in heavy oil, while the enhancement is increased with carbon number of alkanes.Chen, Z., Zhang, X., Liu, Z., Liu, Q., Xu, T., 2018. Quantification of reactive intermediate radicals and their induction effect during pyrolysis of two n-alkylbenzenes. Fuel Processing Technology 178, 126-132. of heavy organic resources follows the radical mechanism. It involves the reactions between radicals generated from the cleavage of covalent bonds in a reactant and the reactions between the radicals and the reactant. The radicals are the reactive intermediates that govern the rate and product distribution of pyrolysis. This paper quantifies the reactive intermediate radicals generated in direct pyrolysis of two n-alkylbenzenes and the induced pyrolysis of the alkylbenzenes by the radicals, based on the data obtained in pyrolysis with and without tetralin that is able to donate hydrogen radicals. It is found that about 90% reactive intermediate radicals can be capped by the hydrogen radicals from tetralin. At 400–440?°C the contribution of induced pyrolysis is more than that of direct pyrolysis, about 1.9 times for n-propylbenzene and 3 times for n-pentylbenzene. The role of induced pyrolysis is larger at higher temperatures due to its higher activation energy than direct pyrolysis.Cheng, B., Xu, J., Liang, Y., Deng, Q., Tian, Y., Liao, Z., 2018. Determination and geochemical implication of multiple series of long-chain oxygen-bearing compounds trapped in kerogen in the Lucaogou Formation, Santanghu Basin, NW China. Organic Geochemistry 121, 68-79. of occluded oxygen-bearing compounds inside kerogen are scarce, although such studies are important in understanding early-stage transformation of organic matter. A relatively low-maturity kerogen from the late Permian mudstone of the Lucaogou Formation of the Santanghu Basin, northwestern China, was successively extracted with n-hexane, acetone and dichloromethane to release the adsorbed components, and the extracted kerogen was treated with a mild oxidation reagent H2O2 to release the occluded components. Gas chromatography–mass spectrometry analysis of the adsorbed and occluded components revealed a suite of oxygen-bearing compounds, including n-alkan-2-ones, n-aldehydes and fatty acid methyl esters. The n-alkan-2-ones were mainly detected in the adsorbed fraction and n-aldehydes in the occluded component. Comparison of the long-chain oxygen-bearing compound distributions and their individual stable carbon isotope characteristics both suggest that the oxygen-bearing compounds released by H2O2 treatment were occluded in the kerogen. The shorter-chain (C15 to C19) occluded n-aldehydes reflected similar isotopic distribution trends to the adsorbed n-alkan-2-ones, and the δ13C values of the mid-length (C21 to C25) occluded n-aldehydes were much closer to the adsorbed n-alkanes. Bacterially mediated methylation and decarbonylation of the n-aldehydes during kerogen formation may be important source(s) of n-alkan-2-ones and n-alkanes, respectively. The mid-chain ketones mainly originated from hydrothermal alteration of n-alkanes after kerogen formation. Uplift of the Lucaogou Formation in the Yuejingou section allowed surface-enhanced aerobic reactions.Cheng, X., Mao, Z., Mao, R., Li, Z., Guan, Q., Chen, X., 2018. Families of reservoired crude oils from the Cangdong Sag, Bohai Bay Basin, China. Organic Geochemistry 122, 115-125. organic geochemistry of 35 crude oils from six oil fields across the Cangdong Sag, Bohai Bay Basin, was characterized and an oil family classification was carried out for the first time. Four oil families were classified based on 18 parameters related to source and depositional environment using hierarchical cluster analysis. The families have broadly similar geochemical characteristics which suggest oils derived from lacustrine source rocks deposited in a reducing environment. Family A has relatively abundant C27 steranes and C30 4α-methyl-24-ethylcholestanes, high Pr/Ph, C22/C21 tricyclic terpane and C31R/C30 hopane ratios, and low ETR, C26/C25 tricyclic terpane and C35S/C34S homohopane ratios. Family A shows higher thermal maturity than families C and D, but lower than family B. The most distinct feature for Family B is the high gammacerane index; they also show slightly higher C22/C21 tricyclic terpane, C31R/C30 hopane and C29/C30 hopane, lower dibenzothiophene/phenanthrene, and higher maturity than the other families. Families C and D oils are low maturity and they are more similar to each other than families A and B based on most biomarker ratios. However, family C can be distinguished from family D by slightly higher C27/C29 steranes and C30 4Me/C29 steranes C30 4α-methyl-24-ethylcholestanes/C29 steranes, and lower C29 steranes/C30 hopane ratios. A preliminary oil–source rock correlation suggests that the oil families originated from various intervals having different organofacies within the second member of the Kongdian Formation. Family A is more widespread than the other families, supporting extensive distribution of the source rock. Family B was only found in the southern part of Kongdong slope, which suggests limited geographical distribution of the related source rock. Families C and D show similar geographical distributions and dominate Wangguantun, Shenjiapu and Shenvsi fields, suggesting that the source kitchens are near these regions.Chim, L.K., Yen, J.-Y., Huang, S.-Y., Liou, Y.-S., Tsai, L.L.-Y., 2018. Using Raman spectroscopy of carbonaceous materials to track exhumation of an active orogenic belt: An example from eastern Taiwan. Journal of Asian Earth Sciences 164, 248-259. burial and exhumation history of an orogen can provide insights into the thermal history of rocks in the mountain belt. Asynchronous collision will exhume materials to the surface at different times and expose different metamorphic grades along the orogenic axis. By tracking the thermal signals of eroded materials, it is possible to compare spatial patterns of exhumation along the mountain belt. Previous studies such as bulk mineralogy of sandstones, crystallinity of clay minerals, and fission track thermochronology all suggest that the Pliocene to Pleistocene meta-sedimentary deposits within the preserved basins of the Coastal Range reflect the unroofing history of the Central Range in Eastern Taiwan. In this study, modern sediments from six drainages of the east Central Range (Liwu, Mugua, Laku- Laku, Luye, Jinlun, and Hsuhai Rivers) and three basin sections of meta-sedimentary deposits from the Coastal Range (Shuilien, Chimei, and Madagida sections) were sampled to reconstruct the thermal signals of each drainage along the modern orogenic axis and reconstruct temporal variations of thermal signals in preserved Plio-Pleistocene sedimentary rocks.The temperature index (T.I.) of modern sediments determined by Raman spectroscopy of carbonaceous materials are medium to high (0.4–0.8). In conjunction with bio- and magneto-stratigraphy, our data suggest that the northern Shuilien area has been receiving detritus of medium metamorphic grade from the exhumed orogeny in the north from 3.4?Ma and higher grade since 2?Ma; meanwhile, the southern Madagida section has been mostly taking in juvenile detritus from the south part of the orogen until 1?Ma. The central Chimei section has started collecting mature detritus since 1.24?Ma. The data suggest that the Plio-Pleistocene basins contain a good record of orogen evolution.Cho, J., Kim, T.H., Chang, N., Lee, K.S., 2018. Effects of relative permeability change resulting from interfacial tension reduction on vertical sweep efficiency during the CO2-LPG hybrid EOR process. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 40, 1242-1249. addition of liquefied petroleum gas (LPG) to the CO2 stream reduces interfacial tension (IFT) between the injected gas and the reservoir oil, and it changes the gas-liquid relative permeability by making it more water-wet, which affects not only the oil mobility, but also the vertical sweep efficiency. The reduction of the IFT decreases vertical sweep efficiency because it enhances the relative permeability of the solvent, resulting in an increase in the viscous gravity number. For CO2-LPG enhanced oil recovery (EOR), oil recovery is enhanced by up to 47%, as compared to CO2 flooding, when the relative permeability change caused by the IFT is not considered. By taking the vertical sweep-out caused by IFT and relative permeability change into consideration, this increase is reduced to 40%. These results indicate the importance of considering the relative permeability and IFT change when predicting the performance of the CO2-LPG EOR process.Choi, J.H., Dai, S., Lin, J.S., Seol, Y., 2018. Multistage triaxial tests on laboratory‐formed methane hydrate‐bearing sediments. Journal of Geophysical Research: Solid Earth 123, 3347-3357. A sound understanding of the geomechanical behavior of hydrate?bearing sediments (HBSs) is essential not only for assessing reservoir and wellbore stability during methane gas production but also for projecting the impact of global warming on the stability of geological settings that contain hydrates. This study experimentally investigated the geomechanical responses of laboratory?formed methane?HBS to triaxial shearing under drained conditions. The hydrate pore habit formed in the sediments is noncontact?cementing, which is different from contact?cementing or grain?coating hydrate pore habits formed when the excessive gas method is used. The multistage triaxial test method, which shears a single specimen under different confinements, was employed to examine its applicability in measuring geomechanical properties of the HBS. Conventional single?stage triaxial tests were also performed to serve as baselines. The results show that both the strength and stiffness of HBS increase with increased hydrate saturation and confining stress. Shear dilatancy increases with increased hydrate saturation and decreased confining stress. The peak strength and peak/postpeak shear dilation measured using the multistage tests are comparable to those using the single?stage tests. However, the stiffness measured in later stress stages in the multistage tests was enhanced by the stress?strain history of earlier stages. Therefore, the multistage test offers an efficient way of measuring the strength and volumetric response of the HBS with a much smaller number of specimens than the single?stage test. This benefits the geomechanical characterization of the HBS, as obtaining the pressure cores is extremely costly and preparing lab samples is usually sophisticated and time consuming.Chong, L., Myshakin, E.M., 2018. Molecular simulations of competitive adsorption of carbon dioxide – methane mixture on illitic clay surfaces. Fluid Phase Equilibria 472, 185-195. dynamics and Monte Carlo simulation studies were carried out to investigate adsorption behavior of carbon dioxide and methane mixtures on illitic clay surfaces under dry conditions. Various compositions of the mixtures and distributions of isomorphic substitutions in clay layers were chosen to explore competitive adsorption depending on component concentration and charge localization. The simulations show that carbon dioxide is preferentially sorbed on the illitic surface and is capable to promote methane desorption. Density distributions of the molecular species in pore space reveal formation of multilayers on the clay surfaces at elevated pressures. Mixed adsorption isotherms were compared with adsorption isotherms of pure compounds and thermodynamic quantities were reported to characterize the interaction of the carbon dioxide and methane with the clay surface.Chou, L., Kenig, F., Murray, A.E., Fritsen, C.H., Doran, P.T., 2018. Effects of legacy metabolites from previous ecosystems on the environmental metabolomics of the brine of Lake Vida, East Antarctica. Organic Geochemistry 122, 161-170. Vida, located in a closed basin in the McMurdo Dry Valleys, East Antarctica, permanently encapsulates an interstitial anoxic, aphotic, cold (?13?°C), brine ecosystem within 27+ m of ice. Metabolically active, but cold-limited, slow-growing bacteria were detected in the brine. Lake Vida brine is derived from the evaporation of a body of water that occupied the same basin prior to ～2800?years ago. The characteristics of this body of water changed over time and, at one point, likely resembled other modern well-studied perennial ice-covered lakes of the Dry Valleys. We characterized the dichloromethane-extractable fraction of the environmental metabolome of Lake Vida brine in order to constrain current and ancient biogeochemical processes. Analysis of the dichloromethane-extract of Lake Vida brine by gas chromatography-mass spectrometry and comprehensive multidimensional gas chromatography-time of flight-mass spectrometry reveals the presence of legacy compounds (i.e. diagenetic products of chlorophylls and carotenoids) deriving from photosynthetic algae and anaerobic, anoxygenic photosynthetic bacteria. This legacy component dilutes the environmental signal of metabolites deriving from the extant bacterial community. The persistence of legacy metabolites (paleometabolites), apparent in Lake Vida brine, is a result of the slow turnover rates of the extant bacterial population due to low metabolic activities caused by the cold limitation. Such paleometabolites may also be preserved in other cold-limited or nutrient-depleted slow-growing ecosystems. When analyzing ecosystems with low metabolic rates, the presence of legacy metabolites must first be addressed in order to confidently recognize and interpret the environmental metabolome of the extant ecosystem.Churakova, O.V., Fonti, M.V., Saurer, M., Guillet, S., Corona, C., Fonti, P., Myglan, V.S., Kirdyanov, A.V., Naumova, O.V., Ovchinnikov, D.V., Shashkin, A., Panyushkina, I., Büntgen, U., Hughes, M.K., Vaganov, E.A., Siegwolf, R.T.W., Stoffel, M., 2018. Heterogeneous response of Siberian tree-ring and stable isotope proxies to the largest Common Era volcanic eruptions. Climate of the Past Discussions 2018, 1-44. volcanic eruptions have far-reaching impacts on global climate and society. Tree rings can provide valuable climatic information on these impacts across different spatial and temporal scales. Here we explore the suitability of tree-ring width (TRW), maximum latewood density (MXD), cell wall thickness (CWT), and δ13C and δ18O in tree-ring cellulose for the detection of climatic changes in northeastern Yakutia (YAK), eastern Taimyr (TAY) and Russian Altai (ALT) sites caused by six largest Common Era stratospheric volcanic eruptions (535, 540, 1257, 1640, 1815 and 1991). Our findings suggest that TRW, MXD, and CWT show strong summer air temperature anomalies in 536, 541–542, 1258–1259 at all study sites. However, they do not reveal distinct and coherent fingerprints after other eruptions. Based on δ13C data, 536 was extremely humid in YAK and TAY, whereas 541 and 542 were humid years in TAY and ALT. In contrast, the 1257 eruption of Samalas likely triggered a sequence of at least two dry summers across all three Siberian sites. No further extreme hydro-climatic anomalies occurred at Siberian sites in the aftermath of the 1991 eruption. Summer sunshine duration decreased significantly in 536, 541–542, 1258–1259 in YAK, and 536 in ALT. Conversely, 1991 was very sunny in YAK. Since climatic responses to large volcanic eruptions are different, and thus affect ecosystem functioning and productivity differently in space and time, a combined assessment of multiple tree-ring parameters is needed to provide a more complete picture of past climate dynamics, which in turns appears fundamental to validate global climate models.Clark, E.B., Bramall, N.E., Christner, B., Flesher, C., Harman, J., Hogan, B., Lavender, H., Lelievre, S., Moor, J., Siegel, V., Stone, W.C., 2018. An intelligent algorithm for autonomous scientific sampling with the VALKYRIE cryobot. International Journal of Astrobiology 17, 247-257. development of algorithms for agile science and autonomous exploration has been pursued in contexts ranging from spacecraft to planetary rovers to unmanned aerial vehicles to autonomous underwater vehicles. In situations where time, mission resources and communications are limited and the future state of the operating environment is unknown, the capability of a vehicle to dynamically respond to changing circumstances without human guidance can substantially improve science return. Such capabilities are difficult to achieve in practice, however, because they require intelligent reasoning to utilize limited resources in an inherently uncertain environment. Here we discuss the development, characterization and field performance of two algorithms for autonomously collecting water samples on VALKYRIE (Very deep Autonomous Laser-powered Kilowatt-class Yo-yoing Robotic Ice Explorer), a glacier-penetrating cryobot deployed to the Matanuska Glacier, Alaska (Mission Control location: 61°42′09.3″N 147°37′23.2″W). We show performance on par with human performance across a wide range of mission morphologies using simulated mission data, and demonstrate the effectiveness of the algorithms at autonomously collecting samples with high relative cell concentration during field operation. The development of such algorithms will help enable autonomous science operations in environments where constant real-time human supervision is impractical, such as penetration of ice sheets on Earth and high-priority planetary science targets like Europa.Cole, J.M., Symes, D.R., Lopes, N.C., Wood, J.C., Poder, K., Alatabi, S., Botchway, S.W., Foster, P.S., Gratton, S., Johnson, S., Kamperidis, C., Kononenko, O., De Lazzari, M., Palmer, C.A.J., Rusby, D., Sanderson, J., Sandholzer, M., Sarri, G., Szoke-Kovacs, Z., Teboul, L., Thompson, J.M., Warwick, J.R., Westerberg, H., Hill, M.A., Norris, D.P., Mangles, S.P.D., Najmudin, Z., 2018. High-resolution μCT of a mouse embryo using a compact laser-driven X-ray betatron source. Proceedings of the National Academy of Sciences 115, 6335-6340.: High-resolution microcomputed tomography with benchtop X-ray sources requires long scan times because of the heat load limitation on the anode. We present an alternative, high-brightness plasma-based X-ray source that does not suffer from this restriction. A demonstration of tomography of a centimeter-scale complex organism achieves equivalent quality to a commercial scanner. We will soon be able to record such scans in minutes, rather than the hours required by conventional X-ray tubes.Abstract: In the field of X-ray microcomputed tomography (μCT) there is a growing need to reduce acquisition times at high spatial resolution (approximate micrometers) to facilitate in vivo and high-throughput operations. The state of the art represented by synchrotron light sources is not practical for certain applications, and therefore the development of high-brightness laboratory-scale sources is crucial. We present here imaging of a fixed embryonic mouse sample using a compact laser–plasma-based X-ray light source and compare the results to images obtained using a commercial X-ray μCT scanner. The radiation is generated by the betatron motion of electrons inside a dilute and transient plasma, which circumvents the flux limitations imposed by the solid or liquid anodes used in conventional electron-impact X-ray tubes. This X-ray source is pulsed (duration <30 fs), bright (>1010 photons per pulse), small (diameter <1 μm), and has a critical energy >15 keV. Stable X-ray performance enabled tomographic imaging of equivalent quality to that of the μCT scanner, an important confirmation of the suitability of the laser-driven source for applications. The X-ray flux achievable with this approach scales with the laser repetition rate without compromising the source size, which will allow the recording of high-resolution μCT scans in minutes.Coleine, C., Stajich, J.E., Zucconi, L., Onofri, S., Pombubpa, N., Egidi, E., Franks, A., Buzzini, P., Selbmann, L., 2018. Antarctic cryptoendolithic fungal communities are highly adapted and dominated by Lecanoromycetes and Dothideomycetes. Frontiers in Microbiology 9, 1392. doi: 1310.3389/fmicb.2018.01392. growth is one of the most spectacular microbial adaptations to extreme environmental constraints and the predominant life-form in the ice-free areas of Continental Antarctica. Although Antarctic endolithic microbial communities are known to host among the most resistant and extreme-adapted organisms, our knowledge on microbial diversity and composition in this peculiar niche is still limited. In this study, we investigated the diversity and structure of the fungal assemblage in the cryptoendolithic communities inhabiting sandstone using a meta-barcoding approach targeting the fungal Internal Transcribed Sequence region 1 (ITS1). Samples were collected from 14 sites in the Victoria Land, along an altitudinal gradient ranging from 1,000 to 3,300 m a.s.l. and from 29 to 96 km distance to coast. Our study revealed a clear dominance of a ‘core’ group of fungal taxa consistently present across all the samples, mainly composed of lichen-forming and Dothideomycetous fungi. Pareto-Lorenz curves indicated a very high degree of specialization (F0 approximately 95%), suggesting these communities are highly adapted but have limited ability to recover after perturbations. Overall, both fungal community biodiversity and composition did not show any correlation with the considered abiotic parameters, potentially due to strong fluctuations of environmental conditions at local scales.Cong, P.-Y., Harvey, T.H.P., Williams, M., Siveter, D.J., Siveter, D.J., Gabbott, S.E., Li, Y.-J., Wei, F., Hou, X.-G., 2018. Naked chancelloriids from the lower Cambrian of China show evidence for sponge-type growth. Proceedings of the Royal Society B: Biological Sciences 285, Article 20180296. are an extinct group of spiny Cambrian animals of uncertain phylogenetic position. Despite their sponge-like body plan, their spines are unlike modern sponge spicules, but share several features with the sclerites of certain Cambrian bilaterians, notably halkieriids. However, a proposed homology of these ‘coelosclerites&#039; implies complex transitions in body plan evolution. A new species of chancelloriid, Allonnia nuda, from the lower Cambrian (Stage 3) Chengjiang Lagerst?tte is distinguished by its large size and sparse spination, with modified apical sclerites surrounding an opening into the body cavity. The sclerite arrangement in A. nuda and certain other chancelloriids indicates that growth involved sclerite addition in a subapical region, thus maintaining distinct zones of body sclerites and apical sclerites. This pattern is not seen in halkieriids, but occurs in some modern calcarean sponges. With scleritome assembly consistent with a sponge affinity, and in the absence of cnidarian- or bilaterian-grade features, it is possible to interpret chancelloriids as sponges with an unusually robust outer epithelium, strict developmental control of body axis formation, distinctive spicule-like structures and, by implication, minute ostia too small to be resolved in fossils. In this light, chancelloriids may contribute to the emerging picture of high disparity among early sponges.Conrad, J.E., Prouty, N.G., Walton, M.A.L., Kluesner, J.W., Maier, K.L., McGann, M., Brothers, D.S., Roland, E.C., Dartnell, P., 2018. Seafloor fluid seeps on Kimki Ridge, offshore southern California: Links to active strike-slip faulting. Deep Sea Research Part II: Topical Studies in Oceanography 150, 82-91. Kimki Ridge fluid seeps are located in western Catalina Basin about 60 km southwest of the southern California mainland and at a water depth of approximately 1100 m. Multichannel seismic reflection profiles collected by the U.S. Geological Survey (USGS) in 2014 show acoustic transparency within the Kimki Ridge, suggesting the possibility of fluid seeps and possible sub-seafloor fluid pathways. Subsequent multibeam bathymetric and backscatter intensity data collected during a cooperative University of Washington/USGS cruise in early 2016 show subtle seafloor buildups with high acoustic backscatter (reflectivity) in three places along Kimki Ridge, supporting the existence of fluid seepage. A Remotely Operated Vehicle (ROV) dive, conducted as part of the Nautilus Exploration Program, took place in August 2016 to confirm the presence of these previously unknown seeps and document their characteristics as well as those of any associated biological communities. Two of the three seeps were explored by ROV, and showed abundant evidence of fluid seepage, including characteristic algal mats, chemosynthetic clams, and authigenic carbonate formation. The seeps are comprised of carbonate buildups 1–3 m thick and 300–500 m across. Within these areas, we interpret broad crater-like depressions 30–50 m across and 1–2 m deep to be individual seep vents. The seep areas appear to be broad zones of diffuse seepage that support chemosynthetic biologic communities; however, active venting was not observed. Geochemical analyses of rock samples collected from the seeps indicate microbially driven anaerobic oxidation of methane at or near the sediment water interface. Seismic-reflection profiles show chimney-like fluid pathways along the limbs and in the axis of the fold forming Kimki Ridge, and evidence of methane in shallow sediments can be traced into the adjacent Catalina Basin. A system of closely spaced faults located at the axis of the Kimki Ridge anticline may serve as pathways to allow fluid flow to the seafloor. Our data are consistent with other studies that suggest that transpression is an important component in the formation and localization of fluid seeps in a strike-slip setting, implying that seep formation may be a common occurrence at fault stepovers or transpressional bends in strike-slip systems.Cornacchia, I., Brandano, M., Raffi, I., Tomassetti, L., Flores, I., 2018. The Eocene–Oligocene transition in the C-isotope record of the carbonate successions in the Central Mediterranean. Global and Planetary Change 167, 110-122. Eocene-Oligocene transition marks a fundamental step in the evolution of the modern climate. This climate change and the consequent major oceanic reorganisation affected the global carbon cycle, whose dynamics across this crucial interval are far from being clearly understood. In this work, the upper Eocene to lower Oligocene δ13CCarb and δ13CTOC records of a shallow-water and a hemipelagic carbonate settings within the Central Mediterranean area have been studied and discussed. The shallow-water carbon isotope signal has been analysed in the northern portion of the Apula Platform, cropping out in the Majella Mountain, Central Apennines (Santo Spirito Formation). A coeval Umbria-Marche basinal succession has been investigated in the Massignano section (Conero area, Central Italy). The purposes of this work are: to discriminate between the global and the local (Mediterranean) signature of C-isotope record during the Oi-1 event, to correlate the regional C-isotope signal with the global record, and to evaluate the carbon cycle dynamics across the greenhouse-icehouse transition through the integration of complementary records (shallow-water vs pelagic settings, δ13CCarb vs δ13CTOC ). The upper Eocene carbon isotope record of the analysed successions matches with the global signal. The overall trend shows a decrease of the δ13CCarb and a contemporary increase of the δ13CTOC . The decoupling of the two curves is consistent with a reduced fractionation effect by primary producers that characterised the interval between the Middle Eocene Climatic Optimum and the onset of the Oi-1 event. However, regional factors superimposed the global signal. In fact, the upper Eocene basinal δ13CTOC record is marked by short-term negative spikes, which possibly represent times of higher productivity triggered by the westward subtropical Eocene Neo-tethys current entering from the Arabian-Eurasian gateway. On the contrary, the shallow-water record does not display these short-term productivity pulses. A change in the carbonate factory is only recorded at the Eocene-Oligocene transition, marked by a reduction of the larger benthic foraminifera and the spread of seagrass and corals. Moreover, in the shallow-water record of the Santo Spirito Formation, no major carbon isotope shift related to the Oi-1 event is recorded due to the presence of extensive slumps that disrupt the bedding. These slumps are the main evidence of the sea-level drop that occurred concomitantly with the onset of the Antarctica ice-sheet, which caused the deepening of the storm wave base and increased the instability over the entire ramp.Cram, J.A., Weber, T., Leung, S.W., McDonnell, A.M.P., Liang, J.H., Deutsch, C., 2018. The role of particle size, ballast, temperature, and oxygen in the sinking flux to the deep sea. Global Biogeochemical Cycles 32, 858-876. The ?transfer efficiency? of organic particles from the surface to depth is a critical determinant of ocean carbon sequestration. Recently, direct observations and geochemical analyses have revealed a systematic geographical pattern of transfer efficiency, which is highest in high latitude regions and lowest in the subtropical gyres. We evaluate the possible causes of this pattern using a mechanistic model of sinking particle dynamics. The model represents the size distribution of particles, the effects of mineral ballast, seawater temperature (which influences both particle settling velocity and microbial metabolic rates), and O2. Parameters are optimized within reasonable ranges to best match the observational constraints. Our model shows that no single factor can explain the observed pattern of transfer efficiency, but the biological effect of temperature on remineralization rate and particle size effects together can reproduce most of the regional variability with both factors contributing to low transfer efficiency in the subtropical gyres and high transfer efficiency in high latitudes. Particle density from mineral ballast has a similar directional effect to temperature and size but plays a substantially smaller role in our optimum solution, due to the opposing patterns of silicate and calcium carbonate ballasting. Oxygen effects modestly improved model fit by depressing remineralization rates and thus increasing transfer efficiency in the Eastern Tropical Pacific. Our model implies that climate?driven changes to upper ocean temperature and associated changes in surface plankton size distribution would reduce the carbon sequestration efficiency in a warmer ocean.Crampton, J.S., Meyers, S.R., Cooper, R.A., Sadler, P.M., Foote, M., Harte, D., 2018. Pacing of Paleozoic macroevolutionary rates by Milankovitch grand cycles. Proceedings of the National Academy of Sciences 115, 5686-5691.: There has been long-standing debate about the relative roles of intrinsic biotic interactions vs. extrinsic environmental factors as drivers of biodiversity change. Here, we show that, relatively early in the history of complex life, Milankovitch “grand cycles” associated with astronomical rhythms explain between 9 and 16% of variation in species turnover probability (extinction probability plus speciation probability) in a major Early Paleozoic zooplankton group, the graptoloids. These grand cycles would have modulated climate variability, alternating times of relative stability in the environment with times of maximum volatility, which influenced oceanic circulation and structure and thus, phytoplankton populations at the base of the marine food web.Abstract: Periodic fluctuations in past biodiversity, speciation, and extinction have been proposed, with extremely long periods ranging from 26 to 62 million years, although forcing mechanisms remain speculative. In contrast, well-understood periodic Milankovitch climate forcing represents a viable driver for macroevolutionary fluctuations, although little evidence for such fluctuation exists except during the Late Cenozoic. The reality, magnitude, and drivers of periodic fluctuations in macroevolutionary rates are of interest given long-standing debate surrounding the relative roles of intrinsic biotic interactions vs. extrinsic environmental factors as drivers of biodiversity change. Here, we show that, over a time span of 60 million years, between 9 and 16% of the variance in biological turnover (i.e., speciation probability plus species extinction probability) in a major Early Paleozoic zooplankton group, the graptoloids, can be explained by long-period astronomical cycles (Milankovitch “grand cycles”) associated with Earth’s orbital eccentricity (2.6 million years) and obliquity (1.3 million years). These grand cycles modulate climate variability, alternating times of relative stability in the environment with times of maximum volatility. We infer that these cycles influenced graptolite speciation and extinction through climate-driven changes to oceanic circulation and structure. Our results confirm the existence of Milankovitch grand cycles in the Early Paleozoic Era and show that known processes related to the mechanics of the Solar System were shaping marine macroevolutionary rates comparatively early in the history of complex life. We present an application of hidden Markov models to macroevolutionary time series and protocols for the evaluation of statistical significance in spectral analysis.Cúcio, C., Overmars, L., Engelen, A.H., Muyzer, G., 2018. Metagenomic analysis shows the presence of bacteria related to free-living forms of sulfur-oxidizing chemolithoautotrophic symbionts in the rhizosphere of the seagrass Zostera marina. Frontiers in Marine Science 5, 171. doi: 110.3389/fmars.2018.00171. play an important role as ecosystem engineers; they provide shelter to many animals and improve water quality by filtering out nutrients and by controlling pathogens. Moreover, their rhizosphere promotes a myriad of microbial interactions and processes, which are dominated by microorganisms involved in the sulfur cycle. This study provides a detailed insight into the metabolic sulfur pathways in the rhizobiome of the seagrass Zostera marina, a dominant seagrass species across the temperate northern hemisphere. Shotgun metagenomic sequencing revealed the relative dominance of Gamma- and Deltaproteobacteria, and comparative analysis of sulfur genes identified a higher abundance of genes related to sulfur oxidation than sulfate reduction. We retrieved four high-quality draft genomes that are closely related to the gill symbiont of the clam Solemya velum, which suggests the presence of putative free-living forms of symbiotic bacteria. These are potentially highly versatile chemolithoautotrophic bacteria, able to alternate their metabolism between parallel pathways of sulfide oxidation (via sqr and fcc), nitrate reduction (denitrification or DNRA) and carbon fixation (via CBB or TCA cycle), depending on the environmental availability of sulfide. Our results support the hypothesis that seagrass meadows might function as a source of symbionts for invertebrates that inhabit within or around seagrass meadows. While providing ideal conditions for the proliferation of these free-living forms of symbionts, seagrasses would benefit from their genetic versatility, which contributes to sulfide detoxification and ammonium production, the seagrasses' preferred nitrogen source.Cui, H., Kaufman, A.J., Peng, Y., Liu, X.-M., Plummer, R.E., Lee, E.I., 2018. The Neoproterozoic Hüttenberg δ13C anomaly: Genesis and global implications. Precambrian Research 313, 242-262. Neoproterozoic Hüttenberg Formation in northeastern Namibia records a remarkable δ13Ccarb positive excursion with a sustained plateau of values up to +12‰ (i.e., the Hüttenberg anomaly). High-resolution chemostratigraphic analyses of drill core samples spanning the upper Elandshoek and Hüttenberg formations reveal multiple new observations: (1) overall high but oscillatory δ13Ccarb values; (2) δ18Ocarb values ranging from ?8‰ to ?2‰; (3) significant enrichment of 13C in organic carbon and a broad co-variation between δ13Ccarb and δ13Corg; (4) a profound negative excursion in δ34Spyrite from +30‰ to ?10‰; (5) an overall inverse δ13C–δ34S relationship; and (6) 87Sr/86Sr values down to 0.7074 in limestone samples. The new data suggest that the Hüttenberg anomaly records dynamic fluctuations in marine redox conditions, which may include an oxygenation event during the height of the δ13Ccarb positive excursion and a deoxygenation event at its termination. The δ34Spyrite negative excursion suggests the buildup of the marine sulfate reservoir, likely due to enhanced pyrite oxidation during the oxygenation event. The δ34Spyrite increase at the end of the Hüttenberg anomaly may result from a seawater sulfate concentration drawdown towards pre-anomaly conditions. On one hand, the Hüttenberg anomaly may reflect restricted basin signals that are deviated from the Ediacaran open ocean; on the other hand, the Ediacaran Hüttenberg anomaly, together with the Cryogenian δ13Ccarb positive excursions, suggests a stepwise pattern of the Neoproterozoic Oxygenation Event. Both local and global environmental factors may have contributed to the Hüttenberg anomaly. The Hüttenberg anomaly therefore represents a local enhancement of global oxygenation signals. Our data support the emerging view that the Neoproterozoic Oxygenation Event may have facilitated the evolution of early life at that time.Cui, Q., Ma, X., Nakano, K., Nakabayashi, K., Miyawaki, J., Al-Mutairi, A., Marafi, A.M.J., Park, J.-I., Yoon, S.-H., Mochida, I., 2018. Hydrotreating reactivities of atmospheric residues and correlation with their composition and properties. Energy & Fuels 32, 6726-6736. order to better understand the effects of composition and properties of atmospheric residues (AR) on their reactivities for hydrodesulfurization (HDS), hydrodenitrogenation (HDN), hydrodevanadium (HDV), hydrodenickel (HDNi), hydrodeasphaltene (HDAsp), and hydrodeconradson-carbon-residue (HDCCR) in the hydrotreating process, analysis and characterization of three ARs (AA-AR, AB-AR, and AM-AR) from Arabia crudes were conducted, and their hydrotreating reactivities were evaluated in a pilot unit over a catalyst system at 370 °C under a H2 pressure of 13.5 MPa by comparing the conversions of the various species and their rate constants on each catalyst. The overall reactivity of various species decreases in the order of vanadium species > sulfur species ≈ asphaltenes > nickel species > Conradson carbon residue precursor > nitrogen species, regardless of the sources of the ARs. Reactivities of the three ARs in HDS, HDV, and HDAsp increase in the order of AB-AR < AA-AR < AM-AR, while reactivities of the three ARs in HDNi, HDCCR, and HDN are similar. The higher nitrogen and asphaltenes concentrations and larger density of AR have strong and negative effects on the HDS, HDV, and HDAsp reactivities but no significant effect on the HDN, HDNi, and HDCCR reactivities. The B parameter obtained from electron spin resonance analysis can be a good index to predict the HDV reactivity of AR.Cunha, S.C., Fernandes, J.O., 2018. Extraction techniques with deep eutectic solvents. TrAC Trends in Analytical Chemistry 105, 225-239. last years, a plethora of extraction techniques has emerged as environmental-friendly alternatives to conventional extraction procedures. In this particular field, a novel class of solvents known as deep eutectic solvents (DES) has arisen as a new and very promising tool. Compared with conventional organic solvents, DES as well as the so-called natural deep eutectic solvents (NADES) have attracted considerable attention due to the fact that they not only are eco-friendly, non-toxic, and biodegradable organic compounds but also have a low cost, being easy to produce in the own laboratory. The present review provides a critical and organized overview of novel extraction techniques using DES as extracting solvents that were applied in food, biological and environmental sample analysis. An evaluation of how these DES/NADES could improve extraction yields of a variety of analytes and advantages and limitations of each proposal will be discussed and compared with earlier studies.da Cunha, L.C., Hamacher, C., Farias, C.d.O., Kerr, R., Mendes, C.R.B., Mata, M.M., 2018. Contrasting end-summer distribution of organic carbon along the Gerlache Strait, Northern Antarctic Peninsula: Bio-physical interactions. Deep Sea Research Part II: Topical Studies in Oceanography 149, 206-217. carbon (DOC) was determined at the Gerlache Strait, a coastal area off the Northern Antarctic Peninsula, in the austral summers of 2015 and 2016 during NAUTILUS I and II cruises, respectively. Hydrographic conditions in the area were very different between the study years. Despite that, the surface mixed layer displayed higher DOC concentrations compared to intermediate and deeper waters, as a result of the strong water column stratification, for both years. DOC accumulation on the surface is significantly related to the net community production (NCP), and stronger when the nitrate surface deficit (ΔNO3-) is higher (2016). The presence of a surface/subsurface thermal front at the central Gerlache Strait likely promotes the export of surface-produced organic carbon to deeper layers. A weak correlation between DOC and apparent oxygen utilization (AOU) suggests that the degradationof organic carbon in the deeper water column has a small role in oxygen consumption (less than 10%). This “recalcitrant” DOC characteristic below the surface layers observed in this study is similar to that found twenty years ago in the same area (FRUELA campaign, early Summer 1995). The Gerlache Strait allows, as an adequate regional scale study, assessments on the efficiency of the export and distribution of organic carbon in deep water masses in view of the observed trends of freshening, cooling, and lightening in the Antarctic Peninsula shelf waters.Dalmagro, H.J., Lathuillière, M.J., Hawthorne, I., Morais, D.D., Pinto Jr, O.B., Couto, E.G., Johnson, M.S., 2018. Carbon biogeochemistry of a flooded Pantanal forest over three annual flood cycles. Biogeochemistry 139, 1-18. Pantanal is the largest wetland in the world and yet little is known about the variability in carbon (C) dynamics across its flood seasons. We examined the effect of inundation on the C cycle in the 2013–2015 flood cycles illustrated by dissolved CO2, CH4, organic C (DOC) concentration measurements, and optical properties of dissolved organic matter (DOM) evaluated by absorbance and fluorescence spectroscopy with parallel factor analysis (PARAFAC). During the 2015 flood cycle, pCO2 varied between 5973 and 14,292 μatm, with pCH4 concentrations ranging between 2956 and 51,675 μatm respectively, with high temporal variability for both gases. The supersaturation of CO2 and CH4 in relation to the atmospheric equilibrium caused the system to behave as a net source of CO2 and CH4 to the atmosphere with evasion rates of 320?mg CO2 m?2 d?1 and 20?mg CH4 m?2 d?1, respectively. Mean DOC concentration was 7.0?±?0.4?mg L?1 and did not differ between flood cycles. Higher concentrations of DOC were measured at the start (rising floodwaters) and at the end (receding floodwaters) of flood cycles, while lower DOC concentrations were observed during the peak flood. The PARAFAC analysis indicated the presence of five DOM components: humic (C1 and C2) and fulvic type material (C3) showed the highest relative abundance (68.5% of the total PARAFAC component fluorescence), as well as protein-like material (C4 and C5) derived from microorganisms. Our measured diffusive flux levels were below the range of emissions found for wetlands and floodplains for CO2, but were slightly higher for CH4 relative to other studies in lakes and seasonally flooded areas of the Pantanal. The large variations in concentrations of CO2, CH4 and DOC and the optical properties of DOM during the course of each flood cycle suggest a close relationship between carbon and water cycles in this tropical wetland.Daly, R.T., Schultz, P.H., Lassiter, J.C., Loewy, S.W., Thompson, L.M., Spray, J.G., 2018. Contrasting meteoritic signatures within the Clearwater East and Clearwater West impact structures: The view from osmium isotopes. Geochimica et Cosmochimica Acta 235, 262-284. isotopes provide a powerful tool for identifying meteoritic signatures in impactites. We apply the osmium isotope method to impact melt and country rocks from the Clearwater East and Clearwater West craters located in Quebec, Canada. Impact melts from Clearwater East have 187Os/188Os ratios of 0.1281–0.1285. These values indicate a significant meteoritic component, which exceeds that in impact melts at all terrestrial craters studied to date, except Morokweng. Such findings align with earlier results from chromium isotopes and platinum-group elements. In contrast, impact melts from Clearwater West have 187Os/188Os ratios between 6.604 and 59.12. These highly radiogenic ratios are indistinguishable from the 187Os/188Os ratios in country rocks. Hence, osmium isotopes provide no evidence for a meteoritic component in impact melts at Clearwater West. The Clearwater craters formed in almost identical targets. Therefore, target effects cannot readily explain the stark difference between the two Clearwater craters. If melt sheet heterogeneity is similar at the two craters, the probability that melts at Clearwater West host an undetected chondritic component is?<?0.2%. Multiple scenarios may explain the non-detection of a meteoritic signature at West; the possibility of a differentiated achondrite impactor could be tested using chromium isotopes. At Clearwater East, a low impact speed (<10?km?s?1) may best explain the unusually strong meteoritic signature. Although the signature (or its nondetection) at each crater may be related to asymmetric preservation of the impactor component, the results presented here provide further evidence that Clearwater East and Clearwater West were temporally separate impact events.Davies, R.J., 2018. The cause of the 2006 Lusi mud volcano (Indonesia): Please let's not rewrite history. Marine and Petroleum Geology 95, 344. Lusi mud volcano started to erupt at approximately 05:00 on May 29th, 2006 near Sidoarjo, Indonesia (Davies et al., 2007, Mazzini et al., 2007). The mud flowed into houses, schools, government offices, factories, places of worship and agricultural land. It is still erupting today. It led to an estimated 60,000 people losing their homes (Richards, 2011) and there were 13 related fatalities. Given the impact this mud volcano has had on the environment and the lives of the people living near it, research on the evolution of the Lusi mud volcano is to be welcomed and therefore also the paper by Mauri et al. (2017) ‘Insights on the structure of Lusi mud edifice from land gravity data’. But the selective and therefore biased description of what caused the disaster is unwise.The eruption started approximately 150 m from a gas exploration well (Banjar Panji-1). The well had experienced an influx of formation fluid (a ‘kick), 24 hours earlier, between 05:00 and 08:00 on May 28th (Davies et al., 2008). The timing of the eruption was also two days after the Yogyakarta Earthquake which occurred on May 27th 2006 at 05:54 local time. Whether drilling or the earthquake caused the eruption have both been argued in a number of research papers and is an active academic debate (Davies et al., 2008, Mazzini et al., 2009, Lupi et al., 2013, Tingay et al., 2015).The Mauri et al. (2017) paper is not about the cause of the mud volcano but in the introduction the authors raise one of the two potential causes inferring it is the trigger mechanism. The first sentence of the introduction is: ‘In May 2006, following a M6.3 earthquake event in Central Java, Merapi and Semeru volcanoes in Central and East Java showed increased activity (Mazzini et al., 2009). Simultaneously, in an urban area in the south of Sidoarjo, numerous mud eruptions appeared at the surface, ultimately resulting in the birth of the Lusi mud eruption (Mazzini et al., 2007, Sawolo et al., 2009)’. There is no mention in the paper at all of the Banjar Panji-1 well and the fact that this well was being drilled and that it is also considered to be the cause of the eruption. If this bias is not highlighted there is a risk that the cause of the Lusi mud volcano will one day be solely attributed to an earthquake, when the scientific literature clearly demonstrates there are two causes that have been considered.The purpose of this comment is not to get into the details of the earthquake versus drilling trigger because this is covered elsewhere but to simply point out that bias in any research paper should be avoided. Although the paper is not about triggering, scientists have an ethical duty to provide a balanced introduction to the topic. Our scientific duty in this regard is even greater when one is dealing with a subject matter that has had such a significant societal impact.de Barros Damgaard, P., Martiniano, R., Kamm, J., Moreno-Mayar, J.V., Kroonen, G., Peyrot, M., Barjamovic, G., Rasmussen, S., Zacho, C., Baimukhanov, N., Zaibert, V., Merz, V., Biddanda, A., Merz, I., Loman, V., Evdokimov, V., Usmanova, E., Hemphill, B., Seguin-Orlando, A., Yediay, F.E., Ullah, I., Sj?gren, K.-G., Iversen, K.H., Choin, J., de la Fuente, C., Ilardo, M., Schroeder, H., Moiseyev, V., Gromov, A., Polyakov, A., Omura, S., Senyurt, S.Y., Ahmad, H., McKenzie, C., Margaryan, A., Hameed, A., Samad, A., Gul, N., Khokhar, M.H., Goriunova, O.I., Bazaliiskii, V.I., Novembre, J., Weber, A.W., Orlando, L., Allentoft, M.E., Nielsen, R., Kristiansen, K., Sikora, M., Outram, A.K., Durbin, R., Willerslev, E., 2018. The first horse herders and the impact of early Bronze Age steppe expansions into Asia. Science 360, eaar7711.'s Summary: Ancient steppes for human equestrians. The Eurasian steppes reach from the Ukraine in Europe to Mongolia and China. Over the past 5000 years, these flat grasslands were thought to be the route for the ebb and flow of migrant humans, their horses, and their languages. de Barros Damgaard et al. probed whole-genome sequences from the remains of 74 individuals found across this region. Although there is evidence for migration into Europe from the steppes, the details of human movements are complex and involve independent acquisitions of horse cultures. Furthermore, it appears that the Indo-European Hittite language derived from Anatolia, not the steppes. The steppe people seem not to have penetrated South Asia. Genetic evidence indicates an independent history involving western Eurasian admixture into ancient South Asian peoples.Abstract: The Yamnaya expansions from the western steppe into Europe and Asia during the Early Bronze Age (~3000 BCE) are believed to have brought with them Indo-European languages and possibly horse husbandry. We analyzed 74 ancient whole-genome sequences from across Inner Asia and Anatolia and show that the Botai people associated with the earliest horse husbandry derived from a hunter-gatherer population deeply diverged from the Yamnaya. Our results also suggest distinct migrations bringing West Eurasian ancestry into South Asia before and after, but not at the time of, Yamnaya culture. We find no evidence of steppe ancestry in Bronze Age Anatolia from when Indo-European languages are attested there. Thus, in contrast to Europe, Early Bronze Age Yamnaya-related migrations had limited direct genetic impact in Asia.Structured AbstractIntroduction: According to the commonly accepted “steppe hypothesis,” the initial spread of Indo-European (IE) languages into both Europe and Asia took place with migrations of Early Bronze Age Yamnaya pastoralists from the Pontic-Caspian steppe. This is believed to have been enabled by horse domestication, which revolutionized transport and warfare. Although in Europe there is much support for the steppe hypothesis, the impact of Early Bronze Age Western steppe pastoralists in Asia, including Anatolia and South Asia, remains less well understood, with limited archaeological evidence for their presence. Furthermore, the earliest secure evidence of horse husbandry comes from the Botai culture of Central Asia, whereas direct evidence for Yamnaya equestrianism remains elusive.Rationale: We investigated the genetic impact of Early Bronze Age migrations into Asia and interpret our findings in relation to the steppe hypothesis and early spread of IE languages. We generated whole-genome shotgun sequence data (~1 to 25 X average coverage) for 74 ancient individuals from Inner Asia and Anatolia, as well as 41 high-coverage present-day genomes from 17 Central Asian ethnicities.Results: We show that the population at Botai associated with the earliest evidence for horse husbandry derived from an ancient hunter-gatherer ancestry previously seen in the Upper Paleolithic Mal’ta (MA1) and was deeply diverged from the Western steppe pastoralists. They form part of a previously undescribed west-to-east cline of Holocene prehistoric steppe genetic ancestry in which Botai, Central Asians, and Baikal groups can be modeled with different amounts of Eastern hunter-gatherer (EHG) and Ancient East Asian genetic ancestry represented by Baikal_EN.In Anatolia, Bronze Age samples, including from Hittite speaking settlements associated with the first written evidence of IE languages, show genetic continuity with preceding Anatolian Copper Age (CA) samples and have substantial Caucasian hunter-gatherer (CHG)–related ancestry but no evidence of direct steppe admixture.In South Asia, we identified at least two distinct waves of admixture from the west, the first occurring from a source related to the Copper Age Namazga farming culture from the southern edge of the steppe, who exhibit both the Iranian and the EHG components found in many contemporary Pakistani and Indian groups from across the subcontinent. The second came from Late Bronze Age steppe sources, with a genetic impact that is more localized in the north and west.Conclusion: Our findings reveal that the early spread of Yamnaya Bronze Age pastoralists had limited genetic impact in Anatolia as well as Central and South Asia. As such, the Asian story of Early Bronze Age expansions differs from that of Europe. Intriguingly, we find that direct descendants of Upper Paleolithic hunter-gatherers of Central Asia, now extinct as a separate lineage, survived well into the Bronze Age. These groups likely engaged in early horse domestication as a prey-route transition from hunting to herding, as otherwise seen for reindeer. Our findings further suggest that West Eurasian ancestry entered South Asia before and after, rather than during, the initial expansion of western steppe pastoralists, with the later event consistent with a Late Bronze Age entry of IE languages into South Asia. Finally, the lack of steppe ancestry in samples from Anatolia indicates that the spread of the earliest branch of IE languages into that region was not associated with a major population migration from the steppe.Dehaghani, Y.H., Assareh, M., Feyzi, F., 2018. Asphaltene precipitation modeling with PR and PC-SAFT equations of state based on normal alkanes titration data in a Multisolid approach. Fluid Phase Equilibria 470, 212-220. fluid Asphaltenes show different precipitation behavior during titration with different normal paraffins, reminding a polydisperse nature. In this respect, the precipitated Asphaltene is increased with decreasing the solvent carbon number. Titration experimental data can be used to improve the precipitation model flexibility. In this study, an improved thermodynamic model is developed to calculate the Asphaltene precipitation conditions. The main focus of this work is on the maximum use of experimental data to increase the accuracy of Asphaltene precipitation calculation using perturbed chain statistical associating fluid theory (PC-SAFT) and Peng-Robinson (PR) equations of state (EOS) (including volume shift) in a Multisolid framework. To do so, at first, PR and PC-SAFT Asphaltene parameters are regressed to bubble point pressure, precipitation onset pressure and the amount of precipitated Asphaltene using the published experimental data on titration of dead oil using normal pentane as a solvent in atmospheric conditions. Afterwards, to follow the polydisperse behavior, the Asphaltene component is divided into three pseudo-components based on the precipitating solvents and the calculations are repeated to adjust the parameters of the EOSs of the new Asphaltene parts. Finally, the results for monodisperse and polydisperse Asphaltene are compared with experimental date of two types of Mexican crude oil samples from reliable published literature and the modeling results with statistical associating fluid theory for the potentials of variable attractive range (SAFT-VR) used by Buenrostro-Gonzalez et?al. [1]. The maximum and minimum deviations from the experimental data to calculate the weight percent of the precipitated Asphaltene after dilution are obtained by PR EOS for monodisperse and by PC-SAFT EOS for polydisperse Asphaltene. For one of the oil samples the maximum and minimum mean percent deviation by PR and PC-SAFT EOSs are 9.1079 and 1.7279, respectively, while for the other oil sample they are 3.6674 and 1.0845, respectively.Delarue, F., Derenne, S., Sugitani, K., Baudin, F., Westall, F., Kremer, B., Tartèse, R., Gonzalez, A., Robert, F., 2018. What is the meaning of hydrogen-to-carbon ratio determined in Archean organic matter? Organic Geochemistry 122, 140-146. search for hydrocarbon molecular biomarkers in Archean metasediments is of prime importance for deciphering the early evolution of life. Suitable criteria are required to identify promising targets for further molecular biomarkers. Possible criteria include the Hydrogen-to-Carbon (H/C) atomic ratio used as a proxy of the aliphatic content of the kerogen matrix. However, H/C ratio values exhibit large variation in Archean kerogens and their significance remains poorly understood. In this study, we thus investigate the significance of the H/C ratios of Archean kerogens by combining elemental analyses, Nanoscale Secondary Ion Mass Spectrometry (NanoSIMS), Rock-Eval pyrolysis and Raman spectroscopy. First, NanoSIMS investigations show the H/C ratio of kerogen can be compromised by residual minerals. In addition, Rock-Eval pyrolysis underlines the fact that thermal cracking of Archean kerogens does not just release hydrocarbon covalently linked to the macromolecular network but also a complex mixture of organic pools distinguished by their thermal maturity. Therefore, the H/C ratio alone cannot be used to probe the preservation of aliphatic compounds bound to kerogen since it can be biased by the presence of (i) residual bitumen, as well as (ii) refractory organic matter in secondary hydrothermal veins whose syngenecity is debatable. Rock-Eval pyrolysis then provides a useful and complementary method to check the significance of H/C atomic ratio as a proxy for hydrocarbon preservation in Archean kerogens.Denis, N., 2018. Editorial. Progress in Biophysics and Molecular Biology 136, 1-2. this issue of the journal we publish a multi-author article (Steele et al., 2018a) on the role of viruses in evolution, including the theory that dormant forms of viruses and conceivably other micro-organisms and, even more remotely, tiny multicellular organisms might have arrived on earth from interplanetary or interstellar space, locked up with sufficient water in comets and other space material. The theory is not a new one, having been first formulated as a scientific hypothesis by Arrhenius in 1903 (Arrhenius, 1903), and revived by Hoyle and Wickramasinghe in the 1970s (Hoyle and Wickramasinghe, 1979). It is also a highly controversial theory, with many biologists dismissing it out of hand. One of the reasons is the difficulty of conceiving how such dormant forms could survive. They would have to do so like dormant seeds, as well as resisting the effects of radiation. The authors propose some ideas on how that might happen. In addition to attributing the origin of life on earth to its seeding from elsewhere in the universe, the article proposes that such seeding continues and may have played a major role, e.g. in the Cambrian explosion.When journals receive ‘way-out’ speculative articles of this kind, they carry a heavy responsibility. The first is to judge whether the theories proposed are empirical and testable. That judgement is not always easy. Physics encounters that kind of problem with, for example, multi-universe theories. In the case of the possible extra-terrestrial origin of life the answer is clear. One day we should be able to know whether invading meteorites and comets contain the ‘seeds of life’.We therefore invited a wide range of referees to review the article. Some declined to do so, either (as in one case) because the referee did not think that the article should even be considered for publication, or because they did not feel competent to judge the science involved. Four referees did agree to review the article and a decision was made based on their recommendations and criticisms. The decision was to publish a revised version of the article after inviting several critical commentaries. We also publish those in this issue (Moelling, 2018, Baverstock, 2018) and a brief reply from the authors of the main article (Steele et al., 2018b). The article has therefore been through extensive review, following the standard practice of the journal, and extending that practice by commissioning open commentaries as well as confidential reviews. This initiative also illustrates the journal's new policy to include interactions between authors and either invited commentators or referees when the editors believe that these interactions will be of interest to readers of the journal.Theories on the origin of life on earth, including the possible role of dormant forms of life from beyond the earth are far from agreed and there are many different approaches. The great majority of biologists favour the terrestrial origin of life, and research on the possible processes by which this could have happened is steadily increasing. This includes attempts to test processes by which living systems could have emerged from the earth's chemistry and attempts to synthesise primitive living organisms using modern DNA and RNA technology.Exploration of our solar system is developing the techniques for detecting relevant organic molecules in extra-terrestrial objects. If we do find viruses or any other forms of life within the solar system it would be deeply significant if we found that the DNA sequences correspond to ones developed during the Cambrian explosion on earth. And even more deeply significant if we were to find totally different forms of life with, e.g. with coding incompatible with forms on earth, or even life forms with no coding molecules. Some origins of life theories include early forms with metabolic networks and no coding molecules, i.e. the metabolism-first theories referenced by one of the commentators, Keith Baverstock.Either way, the stakes are high. With plans for sending humans to Mars, and probes to other moons, asteroids and planets we also have to be careful not to contaminate the very evidence we hope to find.Meanwhile, all we have is speculation. It is in that spirit that we publish the present article. The commentaries published with the article are both very critical of the main idea of the article, one of them ending with the comment that “the main statement about viruses, microbes and even animals coming to us from space, cannot be taken seriously.” Both sides of the argument are therefore represented in the journal.As the editor responsible for the refereeing of the article and for commissioning the commentaries, I believe that our science is advanced by critical review of controversial theories, particularly in an area where so little is known. There really is no agreed theory on how life arose on earth. We simply don't know. All theories therefore are currently ‘way out’ theories. The history of science is littered with way-out theories, most of which have fallen by the wayside, but some of which survived to become today's orthodoxy. As the authors remind us, that was once true of tectonic plate theory, originally ridiculed but now the cornerstone of understanding the origins of the continents.We thank the authors of the article and of the commentaries for being willing to share the arguments in print, and the anonymous referees for their careful work.The usual mantra “further research is needed” applies even more than usual. As space chemistry and biology grows in importance it is appropriate for a journal devoted to the interface between physics and biology to encourage the debates. In the future, the ideas will surely become testable.ReferencesS. Arrhenius, Die Verbreitung des Lebens im Weltenraum, Umschau, 7 (1903), pp. 481-485K. Baverstock, Commentary on: cause of Cambrian explosion – terrestrial or cosmic?, Prog. Biophys. Mol. Biol. (2018)F. Hoyle, N.C. Wickramasinghe, Diseases from Space, J.M. Dent Ltd, London (1979)K. Moelling, Cause of Cambrian explosion - terrestrial or cosmic?, Prog. Biophys. Mol. Biol. (2018)E.J. Steele, et al., Cause of Cambrian explosion - terrestrial or cosmic?, Prog. Biophys. Mol. Biol. (2018)E.J. Steele, et al., Reply to editorial and commentaries on Steele, et al (2018) “Cause of Cambrian explosion - terrestrial or cosmic?”, Prog. Biophys. Mol. Biol. (2018)Desfontaine, V., Losacco, G.L., Gagnebin, Y., Pezzatti, J., Farrell, W.P., González-Ruiz, V., Rudaz, S., Veuthey, J.-L., Guillarme, D., 2018. Applicability of supercritical fluid chromatography – mass spectrometry to metabolomics. I – Optimization of separation conditions for the simultaneous analysis of hydrophilic and lipophilic substances. Journal of Chromatography A 1562, 96-107. aim of this study was to evaluate the suitability of SFC-MS for the analysis of a wide range of compounds including lipophilic and highly hydrophilic substances (log P values comprised between ?6 and 11), for its potential application toward human metabolomics. For this purpose, a generic unified chromatography gradient from 2 to 100% organic modifier in CO2 was systematically applied. In terms of chemistry, the best stationary phases for this application were found to be the Agilent Poroshell HILIC (bare silica) and Macherey-Nagel Nucleoshell HILIC (silica bonded with a zwitterionic ligand). To avoid system overpressure at very high organic modifier proportion, columns of 100?×?3?mm I.D. packed with sub-3?μm superficially porous particles were selected. In terms of organic modifier, a mixture of 95% MeOH and 5% water was selected, with 50?mM ammonium formate and 1?mM ammonium fluoride, to afford good solubility of analytes in the mobile phase, limited retention for the most hydrophilic metabolites and suitable peak shapes of ionizable species. A sample diluent containing 50%ACN/50% water was employed as injection solvent.These conditions were applied to a representative set of metabolites belonging to nucleosides, nucleotides, small organic acids, small bases, sulfated/sulfonated metabolites, poly-alcohols, lipid related substances, quaternary ammonium metabolites, phosphate-based substances, carbohydrates and amino acids. Among all these metabolites, 65% of the compounds were adequately analyzed with excellent peak shape, 23% provided distorted peak shapes, while only 12% were not detected (mostly metabolites having several phosphate or several carboxylic acid groups).Dibike, Y.B., Shakibaeinia, A., Droppo, I.G., Caron, E., 2018. Modelling the potential effects of Oil-Sands tailings pond breach on the water and sediment quality of the Lower Athabasca River. Science of The Total Environment 642, 1263-1281. the Oil-Sands industry in Alberta, Canada, tailings ponds are used as water recycling and tailings storage facilities (TSF) for mining activities. However, there could be possible circumstances under which a sudden breach of an embankment confining one of the TSFs may occur. Such a tailings pond breach would result in a sudden release of a huge volume of Oil Sands process-affected water (OSPW) and sediment slurry containing substantial amount of chemical constituents that would follow the downstream drainage paths and subsequently enter into the Lower Athabasca River (LAR). This study investigates the implications of OS tailings release on the water and sediment quality of the LAR by simulating the fate of sediment and associated chemicals corresponding to a hypothetical breach and release scenarios from a select set of tailings ponds using a two-dimensional hydrodynamic and constituent transport model. After predicting the total volume, time evolution and concentration of sediment and associated chemicals (metals, polycyclic aromatic hydrocarbons (PAHs) and naphthenic acids (NAs)) reaching the LAR, the transport and deposition of these materials within the study reach is simulated. The results show that, depending on tailings release locations, between 40 and 70% of the sediment and associated chemicals get deposited onto the river bed of the 160?km study reach while the rest leaves the study domain during the first three days following the release event. These sediment/chemicals deposited during the initial spill may also have long-term effects on the water quality and aquatic ecosystem of the river and the downstream delta. However, care has to be taken in interpreting the results as further analysis has shown that the outcomes of such model simulations are very sensitive to the various underlying assumptions as well as the values assigned to some model parameters representing the physical properties of the tailings material.Dick, G.J., Grim, S.L., Klatt, J.M., 2018. Controls on O2 production in cyanobacterial mats and implications for Earth's oxygenation. Annual Review of Earth and Planetary Sciences 46, 123-147. mats are widely assumed to have been globally significant hot spots of biogeochemistry and evolution during the Archean and Proterozoic, but little is known about their quantitative contributions to global primary productivity or Earth's oxygenation. Modern systems show that mat biogeochemistry is the outcome of concerted activities and intimate interactions between various microbial metabolisms. Emerging knowledge of the regulation of oxygenic and sulfide-driven anoxygenic photosynthesis by versatile cyanobacteria, and their interactions with sulfur-oxidizing bacteria and sulfate-reducing bacteria, highlights how ecological and geochemical processes can control O2 production in cyanobacterial mats in unexpected ways. This review explores such biological controls on O2 production. We argue that the intertwined effects of light availability, redox geochemistry, regulation and competition of microbial metabolisms, and biogeochemical feedbacks result in emergent properties of cyanobacterial mat communities that are all critical yet largely overlooked mechanisms to potentially explain the protracted nature of Earth's oxygenation.Dillon, J.T., Lash, S., Zhao, J., Smith, K.P., van Dommelen, P., Scherer, A.K., Huang, Y., 2018. Bacterial tetraether lipids in ancient bones record past climate conditions at the time of disposal. Journal of Archaeological Science 96, 45-56. impacts of climate change on ancient human societies requires accurate reconstructions of regional climate variations. However, due to the scarcity of in situ climate indicators in archaeological sites, climate interpretation often relies on indirect, geographically distant data from geological archives such as lake or ocean sediments, ice cores and speleothems. Because many cultural changes occurred abruptly over periods of years to decades, and are regional or even local in scale, correlating societal changes with climate reconstructions from geological archives induces significant uncertainties: factors such as chronological dating inconsistencies and geographic heterogeneity of climate can severely undermine interpretation. Here we show, for the first time, that it is possible to determine past climate change by analyzing bacteria-derived ‘branched glycerol dialkyl glycerol tetraethers’ (br-GDGTs) in ancient bones from archaeological sites. To the best of our knowledge this proxy has never been applied before to bones, nor with the intention of developing the method for application in archaeological research. We demonstrate that these compounds are likely derived from bacterial growth within bones following deposition in the ground, and the potential for their distributions to reflect climate and environmental conditions during the years immediately following deposition when bacteria consume internal substrates. Our preliminary results show that bone samples from different climate zones display distinct br-GDGT distributions. Well-dated late Pleistocene and Holocene bones from Alaska yield reconstructed temperatures consistent with existing climate reconstructions. While further work is necessary to determine how quickly the signal stabilizes in the bones, and to continue ongoing refinement of calibrations for temperature, precipitation, and other influences on br-GDGTs, we propose that br-GDGTs from ancient bones in archaeological sites may be taken as a new, in situ archive for reconstructing past climate conditions. This opens new perspectives for assessing connections between climate variations and social transformations in the past.Djokic, T., Van Kranendonk, M.J., 2018. Textural biosignatures from the Pilbara: an important benchmark for early life on Earth. PalZ 92, 191-193. Pilbara Craton of Western Australia provides unique preservation of some of the best and earliest evidence of life on Earth. The ~?3.5 Ga Dresser Formation, located in the North Pole Dome of the East Pilbara Terrane, displays converging lines of evidence indicative of thriving communities of microorganisms (Buick and Dunlop 1990; Nijman et al. 1998; Van Kranendonk et al. 2008; Djokic et al. 2017). Discovered in the 1970s, Dresser Formation stromatolites were interpreted as forming in a quiet, shallow water marine environment much like modern Shark Bay, Western Australia (Walter et al. 1980; Buick and Dunlop 1990). However, the paleoenvironmental model has changed dramatically, showing that at least some of this ancient life grew in a dynamic volcanic caldera that manifested land-based hot springs (Nijman et al. 1998; Van Kranendonk and Pirajno 2004; Van Kranendonk et al. 2008; Harris et al. 2009; Djokic et al. 2017). Biosignatures include stromatolites, putative microfossils, and stable isotopic data, which have been used to indicate phototrophic and chemotrophic communities including methanogens and sulphur cycling metabolisms (Ueno et al. 2004; Shen et al. 2009; Glikson et al. 2008; Morag et al. 2016). Presented here is a brief review of textural biosignatures in the ~?3.5 Ga Dresser Formation, observed over 40 years, demonstrating the Pilbara as an important benchmark for the preservation of fossil life on the early Earth.The principle textural biosignatures observed in the Dresser Formation are stromatolites. These exhibit a wide range of morphologies, including conical and domical forms that range in size from centimetres to decimetres in height and width, with varying smooth to undulating laminae (Fig. 1a–c), as well as large mounds of wrinkly laminated stromatolitic mats (Fig. 1d, e) and elongated conical and domical forms (Fig. 1f). Stromatolite distribution appears widespread, having flourished in a range of environments including shallow water marine to fluvio-lacustrine settings, and on land in terrestrial hot springs (Walter et al. 1980; Buick and Dunlop 1990; Van Kranendonk 2006, 2011; Van Kranendonk et al. 2008; Djokic 2015, 2017). Biogenicity of these stromatolites is based on macro- and microscale features, including internal microlaminated fabrics such as irregular and undulated layering (Fig. 1g, h; Buick and Dunlop 1990; Djokic 2015; Djokic et al. 2017). Fragments and clasts of ripped up microbial mats within volcaniclastic breccias and fluvial units, respectively, are evident at multiple stratigraphic levels (Fig. 1i, j). Within unweathered drillcore, sulphur isotopic studies on pyritised stromatolites have indicated the presence of sulphur metabolisers (Philippot et al. 2007; Shen et al. 2009).Recent evidence of microtextural biosignatures include infilled, silicified bubbles and silicified palisade fabric (Djokic et al. 2017). The silicified microscopic bubbles are observed with hot spring geyserite, where they are lined by inward-radiating anatase crystal splays (Fig. 1k). It is uncertain whether the bubbles are metabolic gas derivatives or produced by abiogenic gasses, but their preservation is inferred as the result of entrapment within sticky microbial EPS (Djokic et al. 2017). Palisade fabric is preserved as one very thin (~?250 μm) layer that displays vertically aligned quartz crystals in a 10 cm-thick, finely bedded unit interpreted as hot spring sinter terracettes (Fig. ln; Djokic et al. 2017). In modern sinter terraces, such distinctive “palisade” fabric is formed from in situ silicification of microbial filaments oriented vertical to bedding (Campbell et al. 2015).The macro- to micro-scale textural biosignatures indicated here highlight preservation of life in the Pilbara at ~?3.5 Ga. Currently, the Dresser Formation is the only geological formation of this age on Earth to exhibit such a high degree of preservation and diversity. Life was markedly advanced at this time given the range of biosignatures within the one dynamic setting (shallow water marine to terrestrial hot springs). This diversity implies an appreciably earlier origin of life and is consistent with hints of life in ~?3.7 Ga rocks in Greenland (Nutman et al. 2016). The Dresser volcanic-hydrothermal system, with its terrestrial hot springs, favourably preserves microbial textures as a result of pervasive sulphide- and silica-rich hydrothermal waters, which rapidly entomb and preserve biological fabrics. Considering the high preservation potential at the Dresser Formation, opportunities for continued insights into microbial ecosystems in the Archean appear promising.ReferencesBuick, R., and J.S.R. Dunlop. 1990. Evaporitic sediments of early archaean age from the warrawoona group, north pole, western australia. Sedimentology 37 (2): 247–277.Campbell, K.A., D.M. Guido, P. Gautret, F. Foucher, C. Ramboz, and F. Westall. 2015. Geyserite in hot-spring siliceous sinter: window on earth’s hottest terrestrial (paleo) environment and its extreme life. Earth-Science Reviews 148: 44–64.Djokic, T. 2015. Assessing the link between earth’s earliest convincing evidence of life and hydrothermal fluids: The c. 3.5 ga dresser formation of the north pole dome, pilbara craton, western australia. Thesis MPhil, The University of New South Wales.Djokic, T., M.J. Van Kranendonk, K.A. Campbell, M.R. Walter, and C.R. Ward. 2017. Earliest signs of life on land preserved in ca. 3.5 ga hot spring deposits. Nature communications 8: 15263.Glikson, M., L.J. Duck, S.D. Golding, A. Hofmann, R. Bolhar, R. Webb, J.C.F. Baiano, and L.I. Sly. 2008. Microbial remains in some earliest earth rocks: comparison with a potential modern analogue. Precambrian Research 164 (3): 187–200.Harris, A.C., White, N.C., McPhie, J., Bull, S.W., Line, M.A., Skrzeczynski, R., Mernagh, T.P., and R.M. Tosdal. 2009. Early archean hot springs above epithermal veins, North Pole, Western Australia: new insights from fluid inclusion microanalysis. Economic Geology 104: 793–814.Morag, N., K.H. Williford, K. Kitajima, P. Philippot, M.J. Van Kranendonk, K. Lepot, C. Thomazo, and J.W. Valley. 2016. Microstructure-specific carbon isotopic signatures of organic matter from ～?3.5 ga cherts of the pilbara craton support a biologic origin. Precambrian Research 275: 429–449.Nijman, W., K. Bruijne, and M.E. Valkering. 1998. Growth fault control of early archaean cherts, barite mounds and chert-barite veins, north pole dome, eastern pilbara, western Australia. Precambrian Research 88 (1): 25–52.Nutman, A.P., V.C. Bennett, C.R.L. Friend, M.J. Van Kranendonk, and A.R. Chivas. 2016. Rapid emergence of life shown by discovery of 3,700-million-year-old microbial structures. Nature 537 (7621): 535–538.Philippot, P., M. Van Zuilen, K. Lepot, C. Thomazo, J. Farquhar, and M.J. Van Kranendonk. 2007. Early Archean microorganisms preferred elemental sulphur, not sulphate. Science 317: 1534–1537.Shen, Y., J. Farquhar, A. Masterson, A.J. Kaufman, and R. Buick. 2009. Evaluating the role of microbial sulfate reduction in the early archean using quadruple isotope systematics. Earth and Planetary Science Letters 279 (3): 383–391.Ueno, Y., H. Yoshioka, S. Maruyama, and Y. Isozaki. 2004. Carbon isotopes and petrography of kerogens in?～?3.5-ga hydrothermal silica dikes in the north pole area, western australia. Geochimica et Cosmochimica Acta 68 (3): 573–589.Van Kranendonk, M.J. 2006. Volcanic degassing, hydrothermal circulation and the flourishing of early life on Earth: new evidence from the Warrawoona Group, Pilbara Craton, Western Australia. Earth-Science Reviews 74: 197–240.Van Kranendonk, M.J. 2011. Morphology as an indicator of biogenicity for 3.5–3.2 ga fossil stromatolites from the pilbara craton, western Australia. In Advances in stromatolite geobiology, eds. J. Reitner, N.-V. Quéric, and G. Arp, 537–554. Heidelberg: Springer.Van Kranendonk, M.J., P. Philippot, K. Lepot, S. Bodorkos, and F. Pirajno. 2008. Geological setting of Earth’s oldest fossils in the c. 3.5 Ga Dresser Formation, Pilbara Craton, Western Australia. Precambrian Research 167: 93–124.Van Kranendonk, M.J., and F. Pirajno. 2004. Geochemistry of metabasalts and hydrothermal alteration zones associated with c. 3.45 ga chert and barite deposits: implications for the geological setting of the Warrawoona group, Pilbara Craton, Australia. Geochemistry: Exploration, Environment, Analysis 4 (3): 253–278.Walter, M.R., R. Buick, and J.S.R. Dunlop. 1980. Stromatolites 3400–3500 m year old from the North Pole area, Western Australia. Nature 284: 443–445.Dohm, J.M., Maruyama, S., Kido, M., Baker, V.R., 2018. A possible anorthositic continent of early Mars and the role of planetary size for the inception of Earth-like life. Geoscience Frontiers 9, 1085-1098. Moon has an anorthositic primordial continental crust. Recently anorthosite has also been discovered on the Martian surface. Although the occurrence of anorthosite is observed to be very limited in Earth's extant geological record, both lunar and Martian surface geology suggest that anorthosite may have comprised a primordial continent on the early Earth during the first 600 million years after its formation. We hypothesized that differences in the presence of an anorthositic continent on an Earth-like planet are due to planetary size. Earth likely lost its primordial anorthositic continent by tectonic erosion through subduction associated with a kind of proto-plate tectonics (PPT). In contrast, Mars and the Moon, as much smaller planetary bodies, did not lose much of their anorthositic continental crust because mantle convection had weakened and/or largely stopped, and with time, they had appropriately cooled down. Applying this same reasoning to a super-Earth exoplanet suggests that, while a primordial anorthositic continent may briefly form on its surface, such a continent will be likely transported into the deep mantle due to intense mantle convection immediately following its formation. The presence of a primordial continent on an Earth-like planet seems to be essential to whether the planet will be habitable to Earth-like life. The key role of the primordial continent is to provide the necessary and sufficient nutrients for the emergence and evolution of life. With the appearance of a “trinity” consisting of (1) an atmosphere, (2) an ocean, and (3) the primordial continental landmass, material circulation can be maintained to enable a “Habitable Trinity” environment that will permit the emergence of Earth-like life. Thus, with little likelihood of a persistent primordial continent, a super-Earth affords very little chance for Earth-like life to emerge.?okovi?, N., Mitrovi?, D., ?ivoti?, D., Bechtel, A., Sachsenhofer, R.F., Mati?, V., Glamo?anin, L., Stojanovi?, K., 2018. Petrographical and organic geochemical study of the lignite from the Smederevsko Pomoravlje field (Kostolac Basin, Serbia). International Journal of Coal Geology 195, 139-171. Upper Miocene (Pontian) lignite seams are present in the Smederevsko Pomoravlje field (Kostolac Basin, Serbia). The origin of their organic matter (OM), the characteristics of the depositional environment and certain utilisation properties have been evaluated based on petrographic data, bulk organic geochemical parameters, biomarker patterns and their isotope signatures. Moreover, results of isotopic analysis were used for the investigation of the influence of diagenetic aromatisation on δ13C signatures of biomarkers.The studied lignites are typical humic coals. The OM of lignites is derived from woody vegetation and herbaceous peat-forming plants, with a strong prevalence of the former. The peat-forming vegetation is dominated by decay resistant conifers, including gymnosperm families Cupressaceae, Taxodiaceae, and Pinaceae. Angiosperms occurred in lower amounts. Minor contribution of ferns, fungi and emergent aquatic macrophyta to the biomass is also evident. Chemoautotrophic- and heterotrophic bacteria played an import role during diagenesis. Diagenetic alterations, associated with change in the number of carbon atoms, influence δ13C ratios. Diagenetic aromatisation of di- and non-hopanoid triterpenoids is accompanied with 13C depletion, whereas aromatisation of hopanoids displays the opposite trend.Peatification proceeded in a fresh water environment under variable, anoxic to slightly oxic redox conditions. The lowermost coal seam III accumulated in a topogenous fresh water peat mire with open water areas, which changed occasionally into a wet forest swamp. This resulted in the deposition of mineral-rich coal. The characteristics of lignite in coal seam II are similar to those of coal seam III. This is supported also by generally similar δ13C values of individual biomarkers. Coal seam I is dominated by xylite-rich coal, formed under mesotrophic to ombrotrophic conditions. Rapid flooding of the bogs stopped peat growth in all three coal seams. The ratios of ring-A-degraded and non-degraded aromatic diterpenoids and non-hopanoid triterpenoids, proposed in this study, as well as degree of aromatisation of these biomarkers, reflect changes in the water table.Calorific values of the samples indicate that they meet basic requirements for utilisation in the thermal power plants. None of the lignite samples is suitable for coal briquetting, whereas, based on petrographic data, lignite from coal seam I possesses certain potential for fluidized bed gasification.dos Reis, D.E.S., Rodrigues, R., Moldowan, J.M., Jones, C.M., Brito, M., da Costa Cavalcante, D., Portela, H.A., 2018. Biomarkers stratigraphy of Irati Formation (Lower Permian) in the southern portion of Paraná Basin (Brazil). Marine and Petroleum Geology 95, 110-138. study covers the application of biomarkers as stratigraphic markers in a Lower Permian marine section from the Paraná Basin, southern Brazil. The biomarker variations reveal changes in sedimentary environment that were not detected by sedimentological and paleontological methods and will contribute to high resolution stratigraphy. The Irati Formation contains two lithostratigraphic units: (1) the lower unit (Taquaral Member) is composed of shales, deposited in a marine epicontinental to restricted environment and (2) the upper unit (Assistência Member) which consists of carbonates interbedded with shales and organic-rich shale intervals deposited in a restricted marine environment. The biomarker differences observed in the Taquaral Member can be explained by two different types of organic matter. The lower and upper parts are characterized by a high relative abundance of high molecular weight n-alkanes, C27 (17α) trisnorhopane, C31 αβR homohopane, high hopanes/steranes ratio, and low hydrogen index values. This facies contains greater relative amount of terrestrial organic matter. The low hopanes/steranes ratio, together with the high hydrogen index values and amorphous organic matter relative proportion observed in the middle part of the Taquaral Member indicate a more marine organic matter contribution. In the Assistência Member based on gammacerane/C30 αβ hopane ratio, C28ααα (20R) methylcholestane/C29ααα (20R) methylcholestane ratio, total organic carbon, hydrogen index values, palynofacies and sedimentary structures it was possible to distinguish changes in salinity and redox conditions. The bituminous shales intervals were deposited in an anoxic environment (high total organic carbon, high hydrogen index values, high preserved amorphous organic matter content) with lower salinity (lower gammacerane/C30 αβ hopane and C28ααα (20R) methylcholestane/C29ααα (20R) ethylcholestane ratios) on the other hand, the limestones intervals were deposited in an aerobic environment (low total organic carbon, low hydrogen index va.lues, high oxidized organic matter content) with higher salinity (higher gammacerane/C30 αβ hopane and C28ααα (20R) methylcholestane/C29ααα (20R) methylcholestane ratios).Drake, T.W., Guillemette, F., Hemingway, J.D., Chanton, J.P., Podgorski, D.C., Zimov, N.S., Spencer, R.G.M., 2018. The ephemeral signature of permafrost carbon in an Arctic fluvial network. Journal of Geophysical Research: Biogeosciences 123, 1475-1485. fluvial networks process, outgas, and transport significant quantities of terrestrial organic carbon (C), particularly dissolved organic carbon (DOC). The proportion of permafrost C in these fluxes, however, is poorly constrained. A primary obstacle to the quantification of permafrost‐derived DOC is that it is rapidly respired without leaving a unique tracer of its presence. In this study, we investigated the production of bacterial respiratory carbon dioxide (CO2; measured as dissolved inorganic carbon; DIC) during maximum late‐summer thaw in sites spanning a fluvial network (Kolyma Basin, Siberia) to assess whether the biodegradation of permafrost DOC could be detected by the presence of a persistent aged (14C‐depleted) signature on the DIC pool. Using Keeling plot interpretation of DIC produced in bioincubations of river water, we show that bacteria respire varying sources of DOC moving downstream through the fluvial network. Respiration of permafrost (production of aged CO2) was only detected in heavily permafrost thaw influenced sites. In nonpermafrost thaw impacted sites, ambient DIC was modern (14C‐enriched), but rather than precluding the respiration of permafrost OC upstream, we suggest that 14C‐depleted DIC is overwhelmed by modern DIC. Investigation of dissolved organic matter composition via Fourier transform ion cyclotron resonance mass spectrometry highlighted that elevated levels of aliphatic and nitrogen‐containing compounds were associated with the production of aged DIC, providing molecular‐level insight as to why permafrost‐derived dissolved organic matter is rapidly respired. Overall, results from this study demonstrate the difficulty of tracing inputs of a highly reactive substrate to systems with diverse organic matter sources. Du, S., Pang, S., Shi, Y., 2018. A new and more precise experiment method for characterizing the mineralogical heterogeneity of unconventional hydrocarbon reservoirs. Fuel 232, 666-671. study is aimed to introduce the new and more precise experiment method which could characterize the mineralogical heterogeneity of unconventional hydrocarbon reservoirs. As the 2D characterization methods and techniques still have a large amount of information to be excavated with quite strong vitality, the new method could be used to discover the minerals directly under the FE-SEM combining with the EDS method after considering both the resolution (10?nm) and representativeness (20?mm). The higher the ratio of the maximum to the minimum and the mean square deviation of each mineral parameter in thin sections from 8 different directions, the higher the microscopic heterogeneity of the reservoir. The new method would help to the study on enhancing the remaining unconventional hydrocarbon recovery.Duchamp-Alphonse, S., Siani, G., Michel, E., Beaufort, L., Gally, Y., Jaccard, S.L., 2018. Enhanced ocean-atmosphere carbon partitioning via the carbonate counter pump during the last deglacial. Nature Communications 9, Article 2396. synergistic mechanisms were likely involved in the last deglacial atmospheric pCO2 rise. Leading hypotheses invoke a release of deep-ocean carbon through enhanced convection in the Southern Ocean (SO) and concomitant decreased efficiency of the global soft-tissue pump (STP). However, the temporal evolution of both the STP and the carbonate counter pump (CCP) remains unclear, thus preventing the evaluation of their contributions to the pCO2 rise. Here we present sedimentary coccolith records combined with export production reconstructions from the Subantarctic Pacific to document the leverage the SO biological carbon pump (BCP) has imposed on deglacial pCO2. Our data suggest a weakening of BCP during the phases of carbon outgassing, due in part to an increased CCP along with higher surface ocean fertility and elevated [CO2aq]. We propose that reduced BCP efficiency combined with enhanced SO ventilation played a major role in propelling the Earth out of the last ice age.Duncan, K.D., Fang, R., Yuan, J., Chu, R.K., Dey, S.K., Burnum-Johnson, K.E., Lanekoff, I., 2018. Quantitative mass spectrometry imaging of prostaglandins as silver ion adducts with nanospray desorption electrospray ionization. Analytical Chemistry 90, 7246-7252. (PG) are an important class of lipid biomolecules that are essential in many biological processes, including inflammation and successful pregnancy. Despite a high bioactivity, physiological concentrations are typically low, which makes direct mass spectrometric analysis of endogenous PG species challenging. Consequently, there have not been any studies investigating PG localization to specific morphological regions in tissue sections using mass spectrometry imaging (MSI) techniques. Herein, we show that silver ions, added to the solvent used for nanospray desorption electrospray ionization (nano-DESI) MSI, enhances the ionization of PGs and enables nano-DESI MSI of several species in uterine tissue from day 4 pregnant mice. It was found that detection of [PG + Ag]+ ions increased the sensitivity by ～30 times, when compared to [PG – H]? ions. Further, the addition of isotopically labeled internal standards enabled generation of quantitative ion images for the detected PG species. Increased sensitivity and quantitative MSI enabled the first proof-of-principle results detailing PG localization in mouse uterus tissue sections. These results show that PG species primarily localized to cellular regions of the luminal epithelium and glandular epithelium in uterine tissue. Further, this study provides a unique scaffold for future studies investigating the PG distribution within biological tissue samples.Ebeling, D., ?ekutor, M., Stiefermann, M., Tschakert, J., Dahl, J.E.P., Carlson, R.M.K., Schirmeisen, A., Schreiner, P.R., 2018. Assigning the absolute configuration of single aliphatic molecules by visual inspection. Nature Communications 9, Artcile 2420. absolute configuration of a single molecule by direct visual inspection is the next step in compound identification, with far-reaching implications for medicinal chemistry, pharmacology, and natural product synthesis. We demonstrate the feasibility of this approach utilizing low temperature atomic force microscopy (AFM) with a CO-functionalized tip to determine the absolute configuration and orientation of a single, adsorbed [123]tetramantane molecule, the smallest chiral diamondoid. We differentiate between single enantiomers on Cu(111) by direct visual inspection, and furthermore identify molecular dimers and molecular clusters. The experimental results are confirmed by a computational study that allowed quantification of the corresponding intermolecular interactions. The unique toolset of absolute configuration determination combined with AFM tip manipulation opens?a route for studying molecular nucleation, including chirality-driven assembly or reaction mechanisms.Ebenesersdóttir, S.S., Sandoval-Velasco, M., Gunnarsdóttir, E.D., Jagadeesan, A., Gu?mundsdóttir, V.B., Thordardóttir, E.L., Einarsdóttir, M.S., Moore, K.H.S., Sigur?sson, ?., Magnúsdóttir, D.N., Jónsson, H., Snorradóttir, S., Hovig, E., M?ller, P., Kockum, I., Olsson, T., Alfredsson, L., Hansen, T.F., Werge, T., Cavalleri, G.L., Gilbert, E., Lalueza-Fox, C., Walser, J.W., Kristjánsdóttir, S., Gopalakrishnan, S., ?rnadóttir, L., Magnússon, ?.?., Gilbert, M.T.P., Stefánsson, K., Helgason, A., 2018. Ancient genomes from Iceland reveal the making of a human population. Science 360, 1028-1032.: Opportunities to directly study the founding of a human population and its subsequent evolutionary history are rare. Using genome sequence data from 27 ancient Icelanders, we demonstrate that they are a combination of Norse, Gaelic, and admixed individuals. We further show that these ancient Icelanders are markedly more similar to their source populations in Scandinavia and the British-Irish Isles than to contemporary Icelanders, who have been shaped by 1100 years of extensive genetic drift. Finally, we report evidence of unequal contributions from the ancient founders to the contemporary Icelandic gene pool. These results provide detailed insights into the making of a human population that has proven extraordinarily useful for the discovery of genotype-phenotype associations.Editor's Summary: Founder effects in modern populations. The genomes of ancient humans can reveal patterns of early human migration (see the Perspective by Achilli et al.). Iceland has a genetically distinct population, despite relatively recent settlement (～1100 years ago). Ebenesersdóttir et al. examined the genomes of ancient Icelandic people, dating to near the colonization of Iceland, and compared them with modernday Icelandic populations. The ancient DNA revealed that the founders had Gaelic and Norse origins. Genetic drift since the initial settlement has left modern Icelanders with allele frequencies that are distinctive, although still skewed toward those of their Norse founders. Scheib et al. sequenced ancient genomes from the Channel Islands of California, USA, and Ontario, Canada. The ancient Ontario population was similar to other ancient North Americans, as well as to modern Algonquian-speaking Native Americans. In contrast, the California individuals were more like groups that now live in Mexico and South America. It appears that a genetic split and population isolation likely occurred during the Ice Age, but the peoples remixed at a later date.Egger, M., Riedinger, N., Mogollón, J.M., J?rgensen, B.B., 2018. Global diffusive fluxes of methane in marine sediments. Nature Geoscience 11, 421-425. oxidation of methane provides a globally important, yet poorly constrained barrier for the vast amounts of methane produced in the subseafloor. Here we provide a global map and budget of the methane flux and degradation in diffusion-controlled marine sediments in relation to the depth of the methane oxidation barrier. Our new budget suggests that 45–61?Tg of methane are oxidized with sulfate annually, with approximately 80% of this oxidation occurring in continental shelf sediments (<200?m water depth). Using anaerobic oxidation as a nearly quantitative sink for methane in steady-state diffusive sediments, we calculate that ~3–4% of the global organic carbon flux to the seafloor is converted to methane. We further report a global imbalance of diffusive methane and sulfate fluxes into the sulfate–methane transition with no clear trend with respect to the corresponding depth of the methane oxidation barrier. The observed global mean net flux ratio between sulfate and methane of 1.4:1 indicates that, on average, the methane flux to the sulfate–methane transition accounts for only ~70% of the sulfate consumption in the sulfate–methane transition zone of marine sediments.Ehsan, M., Gu, H., Akhtar, M.M., Abbasi, S.S., Ullah, Z., 2018. Identification of hydrocarbon potential of Talhar Shale: Member of Lower Goru Formation using well logs derived parameters, Southern Lower Indus Basin, Pakistan. Journal of Earth Science 29, 587-593. well logs data only, the evaluation of shale gas hydrocarbon potential of Talhar Shale Member of Lower Goru Formation has been a challenge in Southern Lower Indus Basin in Pakistan. Well logs data analysis is helpful to evaluate the gas potential of source shale rocks. We introduced and applied empirical and graphical method to fulfil this task and derived geochemical parameters from well logs data. The method mentioned is cheap and fast. Talhar Shale has kerogen type III and type II which are montmorillonite clay and have potential to produce oil and gas. Talhar Shale has better sorption property. Empirical formulas are used to derive parameters, using well logs of porosity, density and uranium. Porosity and volume of kerogen, calculated from density log, give average values of 11.8% and 11.4%. Average value of level of maturity index (LMI) derived from log is 0.54, which indicates that it is at the early stage of maturity. Vitrinite reflectance is between 0.5%–0.55% as calculated by graphical method and empirical formula. Talhar Shale is at onset of oil generation, with main products of oil and gas. It is a good potential source in the study area.Eigenbrode, J.L., Summons, R.E., Steele, A., Freissinet, C., Millan, M., Navarro-González, R., Sutter, B., McAdam, A.C., Franz, H.B., Glavin, D.P., Archer, P.D., Mahaffy, P.R., Conrad, P.G., Hurowitz, J.A., Grotzinger, J.P., Gupta, S., Ming, D.W., Sumner, D.Y., Szopa, C., Malespin, C., Buch, A., Coll, P., 2018. Organic matter preserved in 3-billion-year-old mudstones at Gale crater, Mars. Science 360, 1096-1101.: Establishing the presence and state of organic matter, including its possible biosignatures, in martian materials has been an elusive quest, despite limited reports of the existence of organic matter on Mars. We report the in situ detection of organic matter preserved in lacustrine mudstones at the base of the ~3.5-billion-year-old Murray formation at Pahrump Hills, Gale crater, by the Sample Analysis at Mars instrument suite onboard the Curiosity rover. Diverse pyrolysis products, including thiophenic, aromatic, and aliphatic compounds released at high temperatures (500° to 820°C), were directly detected by evolved gas analysis. Thiophenes were also observed by gas chromatography–mass spectrometry. Their presence suggests that sulfurization aided organic matter preservation. At least 50 nanomoles of organic carbon persists, probably as macromolecules containing 5% carbon as organic sulfur molecules.Editor's Summary. Measuring martian organics and methane: The Curiosity rover has been sampling on Mars for the past 5 years (see the Perspective by ten Kate). Eigenbrode et al. used two instruments in the SAM (Sample Analysis at Mars) suite to catch traces of complex organics preserved in 3-billion-year-old sediments. Heating the sediments released an array of organics and volatiles reminiscent of organic-rich sedimentary rock found on Earth. Most methane on Earth is produced by biological sources, but numerous abiotic processes have been proposed to explain martian methane. Webster et al. report atmospheric measurements of methane covering 3 martian years and found that the background level varies with the local seasons. The seasonal variation provides an important clue for determining the origin of martian methane.Eliebid, M., Mahmoud, M., Shawabkeh, R., Elkatatny, S., Hussein, I.A., 2018. Effect of CO2 adsorption on enhanced natural gas recovery and sequestration in carbonate reservoirs. Journal of Natural Gas Science and Engineering 55, 575-584. this study, CO2 injection for the purpose of Enhanced Gas Recovery (EGR) and sequestration after primary recovery is investigated on Pink Desert limestone from Edwards Plateau formation in central-west Texas. In this paper, competitive adsorption of CH4 and CO2 is studied in the temperature range 50?°C–150?°C using a mixture of CO2 and CH4. Methane adsorption on the surface of the carbonate rock reduced from 50?mg/g at 50?°C to 12.4?mg/g at 150?°C due to exothermic nature of physical adsorption of methane on calcite. Addition of 10% CO2 to methane has enhanced the adsorption from 12.4?mg/g for pure methane to 18.3?mg/g for the 10% CO2 gas mixture at 150?°C. Adding CO2 to methane will compete with CH4 on the adsorption sites and due to CO2 high adsorption affinity the total uptake of the system is increased depending on CO2 partial pressure. The adsorption experiments have shown that the adsorption of CO2 on Pink Desert limestone is four times higher than that of CH4 at the same pressure and temperature due to the high affinity of CO2 to the calcite rocks derived from strong electrostatic attraction between CO2 molecules and calcite. The thermodynamic analysis confirmed the high natural selectivity of carbonate toward CO2 with lower heat of adsorption for CO2 and the adsorption is spontaneous at low temperatures. The adsorption-desorption experiments showed that CO2 content of injected gas has a strong influence on natural gas desorption from the rocks. The CO2 content and rock mineralogy influence the desorption isotherm model. The potential of using CO2 in EGR and sequestration applications especially in low temperature reservoirs is discussed. A model that explains the contribution of the desorption of natural gas to the total gas production is proposed.Elkins-Tanton, L.T., 2018. Mars beat Earth in the race for habitable conditions. Nature 558, 522-523. analysis of meteoritic material from Mars provides an accurate timeline of the planet’s early history. The results have major implications for our understanding of the processes involved in rocky-planet formation. During their formation, many rocky planets go through a phase known as a magma ocean, during which they are mostly or completely molten. Many researchers thought that the solidification of Mars’s magma ocean was protracted, perhaps lasting for up to 100 million years (Myr) after the ocean’s formation1–3. But in a paper in Nature, Bouvier et al.4 show that this process was completed in less than 10 Myr. The finding suggests that habitable conditions existed on Mars up to 100 Myr before they did on Earth.In the contest between scientific models, empirical evidence is the arbiter. More than 100 meteorites that originated on Mars have been identified on Earth, providing samples of the Martian crust. And advances in the sensitivity of instruments that measure the concentrations of individual isotopes allow the ages of these materials to be determined with high precision.Bouvier and colleagues looked for minerals known as zircons in Martian meteoritic material. When a zircon crystallizes from its parent magma, its crystal structure allows stray uranium atoms to be trapped in the growing crystal, but rejects lead atoms. Consequently, when researchers study these minerals billions of years later, they can be confident that any lead in the crystals was produced by uranium decay and that no other sources of lead need to be considered. Furthermore, two uranium–lead decay processes (235U to 207Pb and 238U to 206Pb) can be used simultaneously to improve the precision of the results. Uranium–lead geochronology using zircons therefore yields the most precise ages of ancient geological materials that are currently possible.The authors analysed seven hard-earned zircons and obtained ages ranging from 4,476 to 4,430 Myr. For comparison, the first solids in the gas disk around the growing young Sun, known as calcium–aluminium-rich inclusions (CAIs), formed 4,567.3 Myr ago5. Therefore, in the astonishingly short interval of 90 Myr, Mars grew from dust to a planet, solidified from its initial magma-ocean state and formed a crust containing zircons.This result already shows that models predicting a protracted magma-ocean stage on Mars1–3 cannot be correct, but Bouvier and co-workers’ study yielded even finer constraints. The lutetium–hafnium decay process, 176Lu to 176Hf, can be used to constrain the melting history of the zircons’ parent magmas, because the two isotopes behave differently during melting. The authors found that the zircons have unusually low concentrations of 176Hf. This indicates that the parent magmas had lower amounts of 176Lu than would be expected if they originated from the solidified products of Mars’s magma ocean. To form these parent magmas, the planet must have partially melted after it had solidified.Bouvier and colleagues’ findings provide a revised timeline for the early stages of Mars’s history (Fig. 1). The planet grew to approximately its current size within less than 10 Myr (and probably less than 5 Myr) of the formation of CAIs6,7. It then took less than 10 Myr to solidify from its initial magma-ocean phase. To put these timescales into perspective, if the Solar System were one day old, Mars would have fully formed in the first 6 minutes. About 20 Myr after the formation of CAIs, the planet partially melted to produce magmas that rose to the planet’s surface; 70 Myr later, these magmas had solidified to form a zircon-containing crust.The rapid solidification of Mars’s magma ocean has important implications for our understanding of both Mars and the planet’s formation of rocky planets in general. The speediness suggests that heat was easily lost from Mars, which implies that the planet’s atmosphere was relatively thin. Two processes could have produced such an atmosphere: a low release of volatile gases from the magma ocean; and a stripping of the atmosphere by the young Sun8,9. Researchers can now constrain the extent to which such processes occur much more closely, and can apply the results to the young Earth.The early growth and magma-ocean phase of Mars, and, by extension, of other planetary embryos, means that at least some of the planet’s formation probably happened while the gas disk was still present around the young Sun — on average, such disks exist for only a few million years10. Therefore, there is strong reason to think that gas in the disk would have diffused into the magma oceans on these embryos.This diffusion process could help to answer some long-standing questions about, for example, the noble-gas content of Earth. Today, Earth releases noble gases that must have been implanted in the mantle at the time of the planet’s formation. The origin of these gases has been unclear because the rocky material that built Earth contained only a small quantity of noble gases. The diffusion of noble gases from the gas disk directly into the magma ocean might solve the mystery.Finally, Bouvier and co-workers’ timeline allows the early histories of Earth and Mars to be compared directly. About 100 Myr after the formation of CAIs, Earth went through a magma-ocean phase that is thought to have been initiated by the collision of the planet with a Mars-sized body — a collision that led to the formation of the Moon11. Consequently, the authors’ results suggest that Mars had clement conditions, and was possibly even hospitable to the formation of life, for as long as 100 Myr before such conditions existed on Earth. Mars had a head start on Earth in the planetary-evolution game. References1. Debaille, V., Brandon, A. D., Yin, Q. Z. & Jacobsen, B. Nature 450, 525–528 (2007).2. Borg, L. E., Brennecka, G. A. & Symes, S. J. K. Geochim. Cosmochim. Acta 175, 150–167 (2016).3. Kruijer, T. S. et al. Earth Planet. Sci. Lett. 474, 345–354 (2017).4. Bouvier, L. C. et al. Nature 558, 586–589 (2018).5. Connelly, J. N. et al. Science 338, 651–655 (2012).6. Johansen, A., Mac Low, M.-M., Lacerda, P. & Bizzarro, M. Sci. Adv. 1, e1500109 (2015).7. Bollard, J. et al. Sci. Adv. 3, e1700407 (2017).8. Ikoma, M., Elkins-Tanton, L., Hamano, K. & Suckale, J. Space Sci. Rev. 214, 76 (2018).9. Erkaev, N. V. et al. Planet. Space Sci. 98, 106–119 (2014).10. Fu, R. R. et al. Science 346, 1089–1092 (2014).11. Touboul, M., Kleine, T., Bourdon, B., Palme, H. & Wieler, R. Nature 450, 1206–1209 (2007).Ellery, A.A., 2018. Engineering a lunar photolithoautotroph to thrive on the moon – life or simulacrum? International Journal of Astrobiology 17, 258-280. work in developing self-replicating machines has approached the problem as an engineering problem, using engineering materials and methods to implement an engineering analogue of a hitherto uniquely biological function. The question is – can anything be learned that might be relevant to an astrobiological context in which the problem is to determine the general form of biology independent of the Earth. Compared with other non-terrestrial biology disciplines, engineered life is more demanding. Engineering a self-replicating machine tackles real environments unlike artificial life which avoids the problem of physical instantiation altogether by examining software models. Engineering a self-replicating machine is also more demanding than synthetic biology as no library of functional components exists. Everything must be constructed de novo. Biological systems already have the capacity to self-replicate but no engineered machine has yet been constructed with the same ability – this is our primary goal. On the basis of the von Neumann analysis of self-replication, self-replication is a by-product of universal construction capability – a universal constructor is a machine that can construct anything (in a functional sense) given the appropriate instructions (DNA/RNA), energy (ATP) and materials (food). In the biological cell, the universal construction mechanism is the ribosome. The ribosome is a biological assembly line for constructing proteins while DNA constitutes a design specification. For a photoautotroph, the energy source is ambient and the food is inorganic. We submit that engineering a self-replicating machine opens up new areas of astrobiology to be explored in the limits of life.Ellery, A.A., 2018. Robotic astrobiology – prospects for enhancing scientific productivity of mars rover missions. International Journal of Astrobiology 17, 203-217. astrobiology involves the remote projection of intelligent capabilities to planetary missions in the search for life, preferably with human-level intelligence. Planetary rovers would be true human surrogates capable of sophisticated decision-making to enhance their scientific productivity. We explore several key aspects of this capability: (i) visual texture analysis of rocks to enable their geological classification and so, astrobiological potential; (ii) serendipitous target acquisition whilst on the move; (iii) continuous extraction of regolith properties, including water ice whilst on the move; and (iv) deep learning-capable Bayesian net expert systems. Individually, these capabilities will provide enhanced scientific return for astrobiology missions, but together, they will provide full autonomous science capability.Emami Baghdadi, M.H., Darvish, H., Rezaei, H., Savadinezhad, M., 2018. Applying LSSVM algorithm as a novel and accurate method for estimation of interfacial tension of brine and hydrocarbons. Petroleum Science and Technology 36, 1170-1174. of the critical parameters in petroleum and chemical engineering is the interfacial tension between brine and hydrocarbon which has major effects on trapping and residual oil in reservoir pore throat so it becomes one of the interesting topics in enhancement of oil recovery in this work Least squares support vector machine (LSSVM) algorithm was applied as a novel predicting machine for prediction of interfacial tension of brine and hydrocarbons in terms of hydrocarbon carbon number, temperature, pressure and ionic strength of brine. A total number of 175 interfacial tensions were collected from literature in the purpose of training and testing of the model. The root mean squared error (RMSE), average absolute relative deviation (AARD) and the coefficient of determination (R2) were calculated overall datasets as 0.23964, 0.27444 and 0.98509 respectively. The results of study showed that predicting LSSVM machine can be applicable for estimation of interfacial tension and EOR processes.Emo, R.B., Smit, M.A., Schmitt, M., Kooijman, E., Scherer, E.E., Sprung, P., Bleeker, W., Mezger, K., 2018. Evidence for evolved Hadean crust from Sr isotopes in apatite within Eoarchean zircon from the Acasta Gneiss Complex. Geochimica et Cosmochimica Acta 235, 450-462. models for the properties of Hadean-Eoarchean crust encompass a full range of possibilities, involving crust that is anywhere from thick and differentiated to thin and mafic. New data are needed to test and refine these models, and, ultimately, to determine how continents were first formed. The Rb-Sr system provides a potentially powerful proxy for crustal evolution and composition. However, this system has thus far been underutilized in studies on early crustal evolution due to its susceptibility to re-equilibration. Overcoming this issue requires new analytical approaches to micro-sample ancient Sr-rich mineral relics that may retain primary Rb-Sr systematics, allowing for the precise and accurate determination of initial 87Sr/86Sr values. In this study, we used a novel application of laser-ablation multi-collector inductively coupled plasma mass spectrometry to determine the Sr isotope composition of apatite inclusions in >3.6?Ga zircon grains from Eoarchean granodiorite gneisses of the Acasta Gneiss Complex, Slave Province, Canada. The 87Rb-corrected 87Sr/86Sr values of these inclusions are largely identical and are distinctly different from values obtained from altered matrix apatite. The inclusion data provide the first direct estimate of initial 87Sr/86Sr for these ancient rocks. Combining this result with information on the protolith and source-extraction age yields estimates for the range of Rb/Sr values, and by extension composition, that the source of these rocks may have had. The data indicate that continental crust containing over 60?wt% of SiO2 was present in the ca. 4.2?Ga source of the Acasta Gneiss Complex. Thus vestiges of evolved crust must have existed within the primitive proto-continents that were present on the Hadean Earth.Engel, A., Sperling, M., Sun, C., Grosse, J., Friedrichs, G., 2018. Organic matter in the surface microlayer: Insights from a wind wave channel experiment. Frontiers in Marine Science 5, 182. doi: 110.3389/fmars.2018.00182. surface microlayer (SML) is the uppermost thin layer of the ocean and influencing interactions between the air and sea, such as gas exchange, atmospheric deposition and aerosol emission. Organic matter (OM) plays a key role in air-sea exchange processes, but studying how the accumulation of organic compounds in the SML relates to biological processes is impeded in the field by a changing physical environment, in particular wind speed and wave breaking. Here, we studied OM dynamics in the SML under controlled physical conditions in a large annular wind wave channel, filled with natural seawater, over a period of 26 days. Biology in both SML and bulk water was dominated by bacterioneuston, and -plankton, respectively, while autotrophic biomass in the two compartments was very low. In general, SML thickness was related to the concentration of dissolved organic carbon (DOC) but not to enrichment of DOC or of specific OM components in the SML. Pronounced changes in OM enrichment and molecular composition were observed in the course of the study and correlated significantly to bacterial abundance. Thereby, hydrolysable amino acids, in particular arginine, were more enriched in the SML than combined carbohydrates. Amino acid composition indicated that less degraded organic matter accumulated preferentially in the SML. A strong correlation was established between the amount of surfactants coverage and ?-aminobutric acid, suggesting that microbial cycling of amino acids can control physiochemical traits of the SML. Our study shows that accumulation and cycling of OM in the SML can occur independently of recent autotrophic production, indicating a widespread biogenic control of process across the air-sea exchange.Enkhjargal, G., Enkhsaruul, B., Monkhoobor, D., Narangerel, J., Yoshikazu, S., 2018. Characterization and hydrotreatment of shale oils of Mongolian oil shales. Oil Shale 35, 168–182. shale oils of oil shales from Mongolian Khoot, Tesegtiin honhor, Uvurjargalant and Zuun bulag deposits, as well as their distillates were studied by the hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodeoxygenation (HDO) processes for the possibility of improv?ing the quality of liquid products. Elemental and chemical composi?tions of the shale oils, distillates and hydrotreated oils were examined qualitatively and quantitatively, using a Thermo Scientific FLASH2000 CHNS analyzer and an Agilent 6890A gas chromatograph (GC). Hydro?treatment of Khoot shale oil (KH) under different reaction conditions showed that with increasing reaction temperature from 330 to 370 °C, HDN, HDS and HDO increased from 13 to 37%, from 65 to 92% and from 59 to 81%, respectively. Among the shale oils hydrotreated at a temperature of 350 °C for 2h, the Uvurjargalant shale oil (UJ) had the highest conversion by HDN (39%), HDS (89%) and HDO (71%).Eroglu, S., Schoenberg, R., Pascarelli, S., Beukes, N.J., Kleinhanns, I.C., Swanner, E.D., 2018. Open ocean vs. continentally-derived iron cycles along the Neoarchean Campbellrand-Malmani Carbonate platform, South Africa. American Journal of Science 318, 367-408. deposition of large amounts of mixed-valence Fe minerals in iron formations during the Archean and Paleoproterozoic indicates that the Fe(II)aq (aqueous) content of coeval anoxic seawater was likely several hundred μM, compared to ca. 1 to 20 nM of the modern oxygenated ocean. It has been suggested that oxygen production along shallow marine continental shelves, which probably started several hundred million years before the rise of atmospheric oxygen, effectively oxidized Fe(II)aq from deeper seawater and removed it as Fe(III)ppt (poorly soluble precipitates). However, the reconstruction of the marine Fe cycle during the Archean is still incomplete, partly because of diagenetic redox processes that challenge the interpretation of Fe concentration and isotope signatures of sedimentary archives. In this study, we present new Fe concentrations and isotope compositions of carbonate and mudrock samples from the Neoarchean Campbellrand-Malmani carbonate platform (CMCP) in South Africa. These samples are from the shelf facies of the CMCP and in combination with previously published data of Czaja and others (2012) from carbonates and mudrocks of the slope facies, we show that different depositional settings and conditions resulted in different data distributions. Coupled δ56Fe values (?3.685 to +0.083 ‰) and iron concentrations (861–27672 μg g?1) of pure carbonates deposited during open marine conditions, can be explained by partial Fe(II) oxidation between ferruginous deeper water and oxygenated shallow water, leaving the residual Fe(II)aq pool isotopically light, although Fe(II) oxidation by anoxygenic phototrophy cannot be ruled out. Pure carbonates deposited in a peritidal setting, with less exposure to open ocean water, show a smaller Fe isotope variability with δ56Fe values of ?1.207 to ?0.204 permil and Fe concentration range from 388 to 5413 μg g?1, respectively. We propose that the Fe systematics of peritidal carbonates were dominated by early diagenetic Fe cycling between carbonates and adjacent mudrocks. Synchrotron based X-ray adsorption spectroscopy reveals a change in Fe speciation, where Fe(II)-bearing ankerite and Fe-sulfide dominate the carbonates in the lower part of the CMCP, whereas carbonates of the upper part of the CMCP mainly contain Fe(III)-(oxyhydr)oxides. The fact that Fe(III) phases are still preserved argues for a higher oxidation state on the shelf of the upper CMCP. This is likely because of a lower content of reductants in those settings, in particular organic carbon, sulfide species, as well as restricted influx of reducing species from the anoxic open ocean due to the formation of a rimmed margin. Nevertheless, more studies of similar carbonate settings are necessary to verify our model. We propose that unfractionated Fe(II)aq in seawater was about two to three times lower on the shelf (30–310 μM) than along the slope (61–928 μM), which implies that Fe(II)aq was removed from the water column closer to the continent, likely by oxidation and precipitation. Overall, the Fe isotope composition and Fe speciation of CMCP sediments support the presence of molecular oxygen in the shallow-marine system and emphasize the utility of Ca-Mg carbonates as proxies for iron cycling in the aqueous environment. Esmaeili, S., Maaref, S., 2018. Applying the Patel-Teja EoS with regular solution theory to predict the onset of asphaltene precipitation. Fluid Phase Equilibria 473, 112-126. precipitation is one of the most challenging issue in the oil industry which causes many problems within the hydrocarbon transmission and production. During the past decades, numerous methods have been proposed to model and predict the asphaltene precipitation process and the onset point at different conditions. The present research tried to apply the regular solution theory with a liquid-liquid equilibrium to model the asphaltene precipitation and estimate the onset point of asphaltene precipitation for four Canadian bitumens diluted by various n-alkane pure solvents at a range of temperature and pressure. This approach requires the liquid molar volume, mole fraction and solubility parameters for each component. The heavy oil/bitumen can be characterized by SARA fractions and divided into the four different pseudo-components named as Saturates, Aromatics, Resins, and Asphaltene. To calculate the values of solubility parameters, molar volume and density of each SARA fractions, the original and modified Patel-Teja equation of state were employed for the first time. The critical properties of SARA fractions were estimated by the proposed empirical correlations. The measured density and molar weight of SARA fractions were used to tune the model. The model developed here successfully fitted and predicted the onset point and amount of asphaltene precipitation which were reported in previous studies. The effect of pressure up to 25?MPa, temperature ranges from 276.15 to 348.15?K and molecular weight of n-alkane from n-pentane through n-decane were investigated on the onset point of asphaltene precipitation with n-alkane diluent. Our attempt showed that the original Patel-Teja equation of state without the volume shift term can be adopted in the regular solution theory like the PR-EoS and the SRK-EoS to predict the onset point of asphaltene precipitation. The results were in reasonable agreement with previous experimental research.Etiope, G., 2018. Understanding the origin of methane on Mars through isotopic and molecular data from the ExoMars orbiter. Planetary and Space Science 159, 93-96. identification of methane (CH4) and its origin on Mars is a major mandate of the ExoMars mission, because this gas has potential links with biological activity. Starting in 2018, the NOMAD spectrometer suite of the ExoMars Trace Gas Orbiter can measure, in the martian atmosphere, important parameters that can contribute to identification of the origin of methane, i.e., its stable C isotope composition, its isotopologue 13CH3D, and ethane concentrations. Assuming that the gas is produced in subsurface rocks and considering genetic and secondary, post-genetic alteration processes observed on Earth, it is anticipated that isotopic and molecular composition of the gas in the martian atmosphere may have a wide range of values, each reflecting a number of possible genetic mechanisms, microbial, thermogenic or abiotic. Due to oxidation and alterations during migration, the CH4 isotopic signature observable in the martian atmosphere will likely be different from the one originally produced in the subsurface. Although there will likely be a considerable degree of uncertainty regarding the origin of any methane detected by NOMAD, integrating atmospheric with geological analysis can help to reduce the uncertainties.Evans, E.M., Freund, D.M., Sondervan, V.M., Cohen, J.D., Hegeman, A.D., 2018. Metabolic patterns in Spirodela polyrhiza revealed by 15N stable isotope labeling of amino acids in photoautotrophic, heterotrophic, and mixotrophic growth conditions. Frontiers in Chemistry 6, 191. doi: 110.3389/fchem.2018.00191. this study we describe a [15N] stable isotopic labeling study of amino acids in Spirodela polyrhiza (common duckweed) grown under three different light and carbon input conditions which represent unique potential metabolic modes. Plants were grown with a light cycle, either with supplemental sucrose (mixotrophic) or without supplemental sucrose (photoautotrophic) and in the dark with supplemental sucrose (heterotrophic). Labeling patterns, pool sizes (both metabolically active and inactive), and kinetics/turnover rates were estimated for fifteen of the proteinogenic amino acids. Estimation of these parameters followed several overall trends. First, most amino acids showed plateaus in labeling patterns of less than 100% [15N]-labeling, indicating the possibility of a large proportion of amino acids residing in metabolically inactive metabolite pools. Second, total pool sizes appear largest in the dark (heterotrophic) condition, whereas active pool sizes appeared to be largest in the light with sucrose (mixotrophic) growth condition. In contrast turnover measurements based on pool size were highest overall in the light with sucrose experiment, with the exception of leucine/isoleucine, lysine, and arginine, which all showed higher turnover in the dark. K-means clustering analysis also revealed more rapid turnover in the light treatments with many amino acids clustering in lower-turnover groups. Emerging insights from other research were also supported, such as the prevalence of alternate pathways for serine metabolism in non-photosynthetic cells. These data provide extensive novel information on amino acid pool size and kinetics in S. polyrhiza and can serve as groundwork for future metabolic studies.Ezcurra, M.D., Butler, R.J., 2018. The rise of the ruling reptiles and ecosystem recovery from the Permo-Triassic mass extinction. Proceedings of the Royal Society B: Biological Sciences 285, Article 20180361. of the key faunal transitions in Earth history occurred after the Permo-Triassic mass extinction (ca 252.2 Ma), when the previously obscure archosauromorphs (which include crocodylians, dinosaurs and birds) become the dominant terrestrial vertebrates. Here, we place all known middle Permian–early Late Triassic archosauromorph species into an explicit phylogenetic context, and quantify biodiversity change through this interval. Our results indicate the following sequence of diversification: a morphologically conservative and globally distributed post-extinction ‘disaster fauna’; a major but cryptic and poorly sampled phylogenetic diversification with significantly elevated evolutionary rates; and a marked increase in species counts, abundance, and disparity contemporaneous with global ecosystem stabilization some 5 million years after the extinction. This multiphase event transformed global ecosystems, with far-reaching consequences for Mesozoic and modern faunas.Fan, J., Louie, S.M., Rodrigues, D.F., 2018. The influence of salinity, pH, temperature and particles on produced water oil quantification precision and accuracy with confocal laser fluorescence microscopy. Energy & Fuels 32, 6978-6989. present study investigates the effects of different produced water parameters, such as salinity, pH, temperature, and presence of colloidal particles, in oil quantification using confocal laser fluorescence microscopy (CLFM). The study simulates different produced water samples, which typically contains a mixture of oil, salts, and different concentrations of particles. The accuracy of the quantification was not affected by the environmental condition for any of the conditions investigated. On the other hand, under extreme environmental conditions, such as high pH (pH 8), salinity (250000 ppm), and temperatures (60 °C), the precision of the CLFM oil quantification was reduced. Changes in the average oil droplet size upon variation of the environmental conditions generally correlated with the change in CLFM measurement precision. Interfacial tension and DLVO interactions were further evaluated to gain a better mechanistic understanding of how the environmental conditions affect the size or colloidal stability of the oil droplets and therefore impact the precision of CLFM measurements. To obtain an overall understanding of the relationship of the different environmental parameters and oil droplet properties with the level of CLFM measurement precision, multiple correspondence analysis (MCA) and multiple regression analysis were employed. The results showed that conditions of lower salinity, temperature, and SiO2 concentration, as well as neutral pH (pH 7), favor smaller oil droplet sizes (close to 4 μm) in the oil-in-water emulsion and more precise CLFM measurements. The better understanding of the impact of different water chemistries on oil droplet stability will be essential for decision-makers on conditions that could impact the precision of the method. This work presents a new perspective of investigating CLFM as an oil-in-water quantification technology and guidance for engineers operating this novel technology on the optimum environmental conditions to achieve the best performance of the technology.Fan, K., Li, Y., Elsworth, D., Dong, M., Yin, C., Li, Y., Chen, Z., 2018. Three stages of methane adsorption capacity affected by moisture content. Fuel 231, 352-360. adsorption capacity is a key factor in determining shale gas in place (GIP) – requiring that it is determined under in situ moisture conditions. Current methods may be insufficient to investigate these exact characteristics when applied to actual reservoirs with high or variable moisture contents. We propose a heating and cooling (HC) method to prepare shale samples to arbitrary moisture contents (Mc up to 10%). A series of CH4 adsorption experiments on two different types of shale are conducted as a function of Mc at 35?°C, 45?°C, and 55?°C, and at a CH4 pressure of up to 10?MPa. Experimental results indicate that the methane sorption capacity versus moisture content curves exhibit a linear decreasing stage, a flat stage and a convex decreasing stage, separated by two threshold moisture contents. The lower moisture content threshold (Mfc) represents coverage of the entire hydrophilic surface by a monolayer of water. The upper moisture content threshold (Msc) is the point at which no methane is adsorbed on the surface of the clay pores and adsorption capacity is further reduced as moisture content is increased. The linear stage with Mc up to the Mfc is mainly dominated by the competition between water and methane for adsorption sites on the surface of clay pores. Slope value of this stage are affected by pressure, temperature and shale compositions. The flat stage represents that the moisture content has negligible effect on shale adsorption capacity for Mc in the range Mfc to Msc. Methane adsorption capacity decreases in a convex manner above Msc, suggesting water condensation in organic pores as the surface area for methane adsorption is reduced by water blocking. A conceptual Bi-Langmuir model is presented to represent the crucial effects of moisture content on methane adsorption capacity including accurate estimations of original GIP under different reservoir conditions.Fan, Y., Deng, C., Zhang, X., Li, F., Wang, X., Qiao, L., 2018. Numerical study of CO2-enhanced coalbed methane recovery. International Journal of Greenhouse Gas Control 76, 12-23. CO2-enhanced coalbed methane (CO2-ECBM) recovery has been comprehensively investigated, fewer scholars have taken the effect of temperature into account, which brought a large deviation for the study of the influence of CO2-ECBM. In this work, a hydraulic-mechanical-thermal coupled model of CO2-ECBM is established, it combines binary gases (CO2 and CH4) infiltration and diffusion, where non-isothermal adsorption is also considered. The effect of injection pressure and reservoir initial temperature on CO2-ECBM was simulated by the finite element simulation software COMSOL Multiphysics, results show that: the injection of CO2 into coalbed has a good effect on enhancing the production of CH4, and both the CO2 storage rate and CH4 production rate increase with the increase of injection pressure. The effect of initial reservoir temperature on CO2-ECBM is obvious. Since the amount of adsorbed gas in coal decreases with the increase of temperature, the CO2 storage rate and CH4 production rate decrease with the increase of initial reservoir temperature. In the gas extraction process without CO2 injection, the variation of permeability is competition result of two types of factors: the coal matrix shrinkage caused by temperature reduction and gas desorption increase, the other is the coal matrix expansion caused by gas pressure decrease, so the permeability follows the rule of first decreasing and then increasing with the extraction time. The injection of CO2 has a great influence on the permeability of coalbed, adsorption of CO2 by the coal matrix causes the permeability to drop rapidly.Fang, Y., Xu, H., 2018. Study of an Ordovician carbonate with alternating dolomite–calcite laminations and its implication for catalytic effects of microbes on the formation of sedimentary dolomite. Journal of Sedimentary Research 88, 679-695. mechanism of sedimentary dolomite formation has puzzled the geology community for more than a century. Within the past several years, successful synthesis of disordered dolomite under ambient conditions using abiotic materials derived from microbial organisms such as polysaccharides and exopolymeric substances (EPS) has been reported. The success in laboratory experiments has driven this study to find evidence in natural ancient carbonate samples that correlate dolomite formation and the presence of organic matter. A micro-laminated carbonate with alternating dolomite–calcite layers from the mid-Lower Ordovician St. Paul Group from the Central Appalachians in southern Pennsylvania was examined using optical microscopes, X-ray diffraction (XRD), scanning electron microscopy (SEM) with X-ray energy-dispersive spectroscopy, electron microprobe analysis (EPMA), scanning transmission electron microscopy (STEM), laser-induced fluorescence (LIF) imaging, short-wave infrared (SWIR) imaging, and X-ray fluorescence (XRF) imaging. The sample is composed mainly of two types of layers. Dolomite-dominated layers are darker in color, generally thinner, and contain detrital minerals such as quartz and feldspar. In contrast, calcite-dominated layers are lighter in color, thicker, and contain less detrital minerals supported by microcrystalline calcite matrix. In situ XRD, LIF, XRF, and SWIR results show that organic remnants are enriched in the dolomite layers. The coincided spatial distribution confirmed a positive correlation between dolomite and organic matter, and hence provide evidence for microbial-EPS-catalyzed formation of sedimentary dolomite.Fatayer, S., Coppola, A.I., Schulz, F., Walker, B.D., Broek, T.A., Meyer, G., Druffel, E.R.M., McCarthy, M., Gross, L., 2018. Direct visualization of individual aromatic compound structures in low molecular weight marine dissolved organic carbon. Geophysical Research Letters 45, 5590-5598.: Dissolved organic carbon (DOC) is the largest pool of exchangeable organic carbon in the ocean. However, less than 10% of DOC has been molecularly characterized in the deep ocean to understand DOC's recalcitrance. Here we analyze the radiocarbon (14C) depleted, and presumably refractory, low molecular weight (LMW) DOC from the North Central Pacific using atomic force microscopy to produce the first atomic‐resolution images of individual LMW DOC molecules. We evaluate surface and deep LMW DOC chemical structures in the context of their relative persistence and recalcitrance. Atomic force microscopy resolved planar structures with features similar to polycyclic aromatic compounds and carboxylic‐rich alicyclic structures with less than five aromatic carbon rings. These compounds comprise 8% and 20% of the measurable molecules investigated in the surface and deep, respectively. Resolving the structures of individual DOC molecules represents a step forward in molecular characterization of DOC and in understanding its long‐term stability. Plain Language Summary: The marine dissolved organic carbon (DOC) reservoir is similar in size to that of atmospheric carbon dioxide and plays an important role in the ocean carbon cycle. DOC comprises a vast mixture of diverse molecules, the majority of which remain structurally uncharacterized. Identification of DOC molecular structures will aid our understanding of DOC cycling. Here, we present the first images of individual DOC molecules using atomic force microscopy. We compare images of low molecular weight DOC molecules extracted from samples collected at different depths in the North Central Pacific. Our results help unravel the molecular architecture, formation processes, and cycling of marine DOC in the ocean. This work demonstrates that atomic force microscopy can facilitate structure determination in oceanic mixtures and provide an additional complimentary toolbox for analytical techniques in geophysical relevant environments. Fedonkin, M.A., Sergeev, V.N., 2018. Pseudofossils, contaminants, and other hazards in Archean and Proterozoic micropaleontology. Stratigraphy and Geological Correlation 26, 364-365.. Original Russian Text ? M.A. Fedonkin, V.N. Sergeev, 2018, published in Stratigrafiya, Geologicheskaya Korrelyatsiya, 2018, Vol. 26, No. 3, pp. 127–128.Fernandes, S., Mazumdar, A., Bhattacharya, S., Peketi, A., Mapder, T., Roy, R., Carvalho, M.A., Roy, C., Mahalakshmi, P., Da Silva, R., Rao, P.L.S., Banik, S.K., Ghosh, W., 2018. Enhanced carbon-sulfur cycling in the sediments of Arabian Sea oxygen minimum zone center. Scientific Reports 8, Article 8665. of oxygen minimum zone (OMZ) sediments, which are characterized by high input of labile organic matter, have crucial bearings on the benthic biota, gas and metal fluxes across the sediment-water interface, and carbon-sulfur cycling. Here we couple pore-fluid chemistry and comprehensive microbial diversity data to reveal the sedimentary carbon-sulfur cycle across a water-depth transect covering the entire thickness of eastern Arabian Sea OMZ, off the west coast of India. Geochemical data show remarkable increase in average total organic carbon content and aerial sulfate reduction rate (JSO42?) in the sediments of the OMZ center coupled with shallowing of sulfate methane transition zone and hydrogen sulfide and ammonium build–up. Total bacterial diversity, including those of complex organic matter degraders, fermentative and exoelectrogenic bacteria, and sulfate-reducers (that utilize only simple carbon compounds) were also found to be highest in the same region. The above findings indicate that higher organic carbon sequestration from the water-columns (apparently due to lower benthic consumption, biodegradation and biotransformation) and greater bioavailability of simple organic carbon compounds (apparently produced by fermetative microflora of the sediments) are instrumental in intensifying the carbon-sulfur cycle in the sediments of the OMZ center.Field, D.J., Bercovici, A., Berv, J.S., Dunn, R., Fastovsky, D.E., Lyson, T.R., Vajda, V., Gauthier, J.A., 2018. Early evolution of modern birds structured by global forest collapse at the End-Cretaceous mass extinction. Current Biology 28, 1825-1831.e1822. The fossil record and recent molecular phylogenies support an extraordinary early-Cenozoic radiation of crown birds (Neornithes) after the Cretaceous-Paleogene (K-Pg) mass extinction. However, questions remain regarding the mechanisms underlying the survival of the deepest lineages within crown birds across the K-Pg boundary, particularly since this global catastrophe eliminated even the closest stem-group relatives of Neornithes. Here, ancestral state reconstructions of neornithine ecology reveal a strong bias toward taxa exhibiting predominantly non-arboreal lifestyles across the K-Pg, with multiple convergent transitions toward predominantly arboreal ecologies later in the Paleocene and Eocene. By contrast, ecomorphological inferences indicate predominantly arboreal lifestyles among enantiornithines, the most diverse and widespread Mesozoic avialans. Global paleobotanical and palynological data show that the K-Pg Chicxulub impact triggered widespread destruction of forests]. We suggest that ecological filtering due to the temporary loss of significant plant cover across the K-Pg boundary selected against any flying dinosaurs (Avialae) committed to arboreal ecologies, resulting in a predominantly non-arboreal post-extinction neornithine avifauna composed of total-clade Palaeognathae, Galloanserae, and terrestrial total-clade Neoaves that rapidly diversified into the broad range of avian ecologies familiar today. The explanation proposed here provides a unifying hypothesis for the K-Pg-associated mass extinction of arboreal stem birds, as well as for the post-K-Pg radiation of arboreal crown birds. It also provides a baseline hypothesis to be further refined pending the discovery of additional neornithine fossils from the Latest Cretaceous and earliest Paleogene.Finch, B.E., Stefansson, E.S., Langdon, C.J., Pargee, S.M., Stubblefield, W.A., 2018. Photo-enhanced toxicity of undispersed and dispersed weathered Macondo crude oil to Pacific (Crassostrea gigas) and eastern oyster (Crassostrea virginica) larvae. Marine Pollution Bulletin 133, 828-834. the Deepwater Horizon oil spill rapid natural weathering of Macondo crude oil occurred during the transport of oil to coastal areas. In response to the DWH incident, dispersant was applied to Macondo crude oil to reduce the movement of oil to coastal regions. This study aimed to assess the narcotic and phototoxicity of water-accommodated fractions (WAFs) of weathered Macondo crude oil, and chemically-enhanced WAFs of Corexit 9500 to Pacific (Crassostrea gigas) and eastern (Crassostrea virginica) oyster larvae. Phototoxic effects were observed for larval Pacific oysters exposed to combinations of oil and dispersant, but not for oil alone. Phototoxic effects were observed for larval eastern oysters exposed to oil alone and combinations of oil and dispersant. Corexit 9500 did not exhibit phototoxicity but resulted in significant narcotic toxicity for Pacific oysters. Oyster larvae may have experienced reduced survival and/or abnormal development if reproduction coincided with exposures to oil or dispersant.Fletcher, T., Warden, L., Sinninghe Damsté, J.S., Brown, K.J., Rybcynski, N., Gosse, J., Ballantyne, A.P., 2018. The role of elevated atmospheric CO2 and increased fire in Arctic amplification of temperature during the Early to mid-Pliocene. Climate of the Past Discussions 2018, 1-41. mid-Pliocene is a valuable time interval for understanding the mechanisms that determine equilibrium climate at current CO2 concentrations. One intriguing, but not fully understood, feature of the early to mid-Pliocene climate is the amplified arctic temperature response. Current models underestimate the degree of warming in the Pliocene Arctic and validation of proposed feedbacks is limited by scarce terrestrial records of climate and environment, as well as discrepancies in current CO2 proxy reconstructions. Here we reconstruct the CO2 and summer temperature from a re-dated 3.9 +1.5/?0.5?Ma sub-fossil fen-peat deposit on west-central Ellesmere Island, Canada, and investigate fire as a potential feedback to Arctic amplification of warming during the mid-Pliocene. Average CO2 was determined using isotope ratios of mosses to be 440?±?50?ppm. The estimate for average mean summer temperature is 15.4?±?0.8?°C using specific bacterial membrane lipids, i.e. branched glycerol dialkyl glycerol tetraethers. Macro-charcoal was present in all samples from this Pliocene section with notably higher charcoal concentration in the upper part of the sequence. This change in charcoal was synchronous with a change in vegetation that saw fire promoting taxa increase in abundance. Paleovegetation reconstructions are consistent with warm summer temperatures, relatively low summer precipitation and an incidence of fire comparable to fire adapted boreal forests of North America, or potentially central Siberia. To our knowledge, this study represents the furthest northern evidence of fire during the Pliocene and highlights the important role of forest fire in the ecology and climatic processes of the Pliocene High Arctic. The results provide evidence that terrestrial fossil localities in the Pliocene High Arctic were probably formed during warm intervals that coincided with relatively high CO2 concentrations that supported productive biotic communities. This study indicates that interactions between paleovegetation and paleoclimate were mediated by fire in the High Arctic during the Pliocene, even though CO2 concentrations were only ~?30?ppm higher than modern.Folland, C.K., Boucher, O., Colman, A., Parker, D.E., 2018. Causes of irregularities in trends of global mean surface temperature since the late 19th century. Science Advances 4, Article eaao5297. time series of monthly global mean surface temperature (GST) since 1891 is successfully reconstructed from known natural and anthropogenic forcing factors, including internal climate variability, using a multiple regression technique. Comparisons are made with the performance of 40 CMIP5 models in predicting GST. The relative contributions of the various forcing factors to GST changes vary in time, but most of the warming since 1891 is found to be attributable to the net influence of increasing greenhouse gases and anthropogenic aerosols. Separate statistically independent analyses are also carried out for three periods of GST slowdown (1896–1910, 1941–1975, and 1998–2013 and subperiods); two periods of strong warming (1911–1940 and 1976–1997) are also analyzed. A reduction in total incident solar radiation forcing played a significant cooling role over 2001–2010. The only serious disagreements between the reconstructions and observations occur during the Second World War, especially in the period 1944–1945, when observed near-worldwide sea surface temperatures (SSTs) may be significantly warm-biased. In contrast, reconstructions of near-worldwide SSTs were rather warmer than those observed between about 1907 and 1910. However, the generally high reconstruction accuracy shows that known external and internal forcing factors explain all the main variations in GST between 1891 and 2015, allowing for our current understanding of their uncertainties. Accordingly, no important additional factors are needed to explain the two main warming and three main slowdown periods during this epoch.Fornaro, T., Boosman, A., Brucato, J.R., ten Kate, I.L., Siljestr?m, S., Poggiali, G., Steele, A., Hazen, R.M., 2018. UV irradiation of biomarkers adsorbed on minerals under Martian-like conditions: Hints for life detection on Mars. Icarus 313, 38-60. simulations of Martian conditions are essential to develop quantitative models for the survival of organic biomarkers for future Mars exploration missions.In this work, we report the results of ultraviolet (UV) irradiation processing of biomarkers adsorbed on minerals under Martian-like conditions. Specifically, we prepared Mars soil analogues by doping forsterite, lizardite, antigorite, labradorite, natrolite, apatite and hematite minerals with organic compounds considered as potential biomarkers of extant terrestrial life such as the nucleotides adenosine monophosphate (AMP) and uridine monophosphate (UMP). We characterized such Mars soil analogues by means of Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and Confocal Raman Imaging Spectroscopy (CRIS), in order to get insights into the specific molecule-mineral interactions and explore the capabilities of different techniques to reveal diagnostic features of these biomarkers. Then, we performed irradiation experiments in the mid-UV spectral region under simulated Martian conditions and under terrestrial ambient conditions for comparison, monitoring the degradation process through DRIFTS.We observed that degradation under Martian-like conditions occurs much slower than in terrestrial ambient conditions. The minerals labradorite and natrolite mainly promote photodegradation of nucleotides, hematite and forsterite exhibit an intermediate degrading effect, while apatite, lizardite and antigorite do not show any significant catalytic effect on the degradation of the target organic species.Fortney, N.W., He, S., Kulkarni, A., Friedrich, M.W., Holz, C., Boyd, E.S., Roden, E.E., 2018. Stable isotope probing for microbial iron reduction in Chocolate Pots Hot Spring, Yellowstone National Park. Applied and Environmental Microbiology 84.: Chocolate Pots hot springs (CP) is a circumneutral-pH Fe-rich geothermal feature located in Yellowstone National Park. Previous Fe(III)-reducing enrichment culture studies with CP sediments identified close relatives of known dissimilatory Fe(III)-reducing bacterial (FeRB) taxa, including Geobacter and Melioribacter. However, the abundances and activities of such organisms in the native microbial community are unknown. Here, we used stable isotope probing experiments combined with 16S rRNA gene amplicon and shotgun metagenomic sequencing to gain an understanding of the in situ Fe(III)-reducing microbial community at CP. Fe-Si oxide precipitates collected near the hot spring vent were incubated with unlabeled and 13C-labeled acetate to target active FeRB. We searched reconstructed genomes for homologs of genes involved in known extracellular electron transfer (EET) systems to identify the taxa involved in Fe redox transformations. Known FeRB taxa containing putative EET systems (Geobacter, Ignavibacteria) increased in abundance under acetate-amended conditions, whereas genomes related to Ignavibacterium and Thermodesulfovibrio that contained putative EET systems were recovered from incubations without electron donor. Our results suggest that FeRB play an active role in Fe redox cycling within Fe-Si oxide-rich deposits located at the hot spring vent. Importance: The identification of past near-surface hydrothermal environments on Mars emphasizes the importance of using modern Earth environments, such as CP, to gain insight into potential Fe-based microbial life on other rocky worlds, as well as ancient Fe-rich Earth ecosystems. By combining stable carbon isotope probing techniques and DNA sequencing technology, we gained insight into the pathways of microbial Fe redox cycling at CP. The results suggest that microbial Fe(III) oxide reduction is prominent in situ, with important implications for the generation of geochemical and stable Fe isotopic signatures of microbial Fe redox metabolism within Fe-rich circumneutral-pH thermal spring environments on Earth and Mars. Foss, L., Petrukhina, N., Kayukova, G., Amerkhanov, M., Romanov, G., Ganeeva, Y., 2018. Changes in hydrocarbon content of heavy oil during hydrothermal process with nickel, cobalt, and iron carboxylates. Journal of Petroleum Science and Engineering 169, 269-276. conducted autoclave modeling experiments to study the process of upgrading heavy oil in the reservoir conditions and used carboxylates of transition metals (Ni, Co, Fe) as catalyst precursors. The process was carried out at temperatures of 250, 300, and 350?°C in the presence of a naphthenoaromatic hydrogen donor. We found that significant content changes of oil occur at temperatures of 300 and 350?°C accompanied by an increase of light fractions and a decrease of high molecular weight hydrocarbons. We studied the hydrocarbon composition of the initial oil and the products of the hydrothermal process as well as tetralin (proton donor) transformations to determine the patterns of influence of the process conditions and catalyst precursors.Fox, C.A., Abdulla, H.A., Burdige, D.J., Lewicki, J.P., Komada, T., 2018. Composition of dissolved organic matter in pore waters of anoxic marine sediments analyzed by 1H nuclear magnetic resonance spectroscopy. Frontiers in Marine Science 5, 172. doi: 110.3389/fmars.2018.00172. sediments are globally significant sources of dissolved organic matter (DOM) to the oceans, but the biogeochemical role of pore-water DOM in the benthic and marine carbon cycles remains unclear due to a lack of understanding about its molecular composition. To help fill this knowledge gap, we used 1H nuclear magnetic resonance (NMR) spectroscopy to examine depth variability in the composition of pore-water DOM in anoxic sediments of Santa Barbara Basin, California Borderland. Proton detected spectra were acquired on whole samples without pre-concentration to avoid preclusion of any DOM components from the analytical window. Broad unresolved resonance (operationally assigned to carboxyl-rich alicyclic molecules, or CRAM) dominated all spectra. Most of the relatively well-resolved peaks (attributed to biomolecules or their derivatives) appeared at chemical shifts similar to those previously reported for marine DOM in the literature, but at different relative intensities. DOM composition changed significantly within the top 50 cm of the sediment column, where the relative intensity of CRAM increased, and the relative intensity of resolved resonances decreased. The composition of CRAM itself also changed throughout the entire length of the 4.5-m profile, as CRAM protons became increasingly aliphatic at the expense of functionalized protons. Given that pore-water DOM is generated from sedimentary organic matter that includes pre-aged and degraded material, and that DOM could theoretically be subjected to microbial reworking in the pore waters for centuries to millennia, these data suggest that marine sediments may be sources of CRAM that are compositionally unique from CRAM generated in the upper ocean.France, C.A.M., Qi, H., Kavich, G.M., 2018. Combined influence of meteoric water and protein intake on hydrogen isotope values in archaeological human bone collagen. Journal of Archaeological Science 96, 33-44. isotopes in archaeological human bone collagen are poorly understood, but present an opportunity to add new depth to our understanding of ancient populations. The competing influences of meteoric water versus protein intake on human bone collagen hydrogen isotope values were examined through comparison with the well-understood proxies of hydroxyapatite oxygen and collagen nitrogen isotopes, respectively. Consideration of the data set as individual points compared to averaged pools of individuals in each of 11 archaeological sites suggested the latter partially eliminates inherent variability due to food choice or regional movement. Collagen hydrogen isotopes were moderately correlated with hydroxyapatite oxygen isotopes (R?=?0.695, site averages) and collagen nitrogen isotopes (R?=?0.562, site averages). Correlation improved with a multiple linear regression including both oxygen and nitrogen (R?=?0.745, site averages). Correlation between meteoric water hydrogen and oxygen isotope values converted from hydroxyapatite and collagen values, respectively, yielded a slope well below the expected value of ～8 observed directly in meteoric water (i.e. the “meteoric water line”). Correlation between converted meteoric water hydrogen and the measured collagen non-exchangeable hydrogen isotope values showed a slope well below the expected value of 1.0. Theoretical meteoric water hydrogen isotope values and theoretical herbivorous collagen hydrogen isotope values were calculated based on previously established equations in order to construct a hypothetical framework free of trophic level influences. Deviations between actual values and these theoretical values correlated weakly with collagen nitrogen isotope values, suggesting that direct trophic level enrichment/depletion is not controlling the disparity between expected and measured values. The deviations are hypothetically caused by non-local food sources, and a decoupling of expected oxygen and hydrogen relationships as individuals consumed more meat and decreased in vivo non-essential amino acid production. This work presents a new model that facilitates understanding of the complex relationship between meteoric water and protein intake controls on hydrogen isotopes in omnivorous human populations that can potentially inform about past meteoric water values and amounts of animal protein consumption.Fu, T., Touboul, D., Della-Negra, S., Hou?l, E., Amusant, N., Duplais, C., Fisher, G.L., Brunelle, A., 2018. Tandem mass spectrometry imaging and in situ characterization of bioactive wood metabolites in Amazonian tree species Sextonia rubra. Analytical Chemistry 90, 7535-7543. by a necessity for confident molecular identification at high spatial resolution, a new time-of-flight secondary ion mass spectrometry (TOF-SIMS) tandem mass spectrometry (tandem MS) imaging instrument has been recently developed. In this paper, the superior MS/MS spectrometry and imaging capability of this new tool is shown for natural product study. For the first time, via in situ analysis of the bioactive metabolites rubrynolide and rubrenolide in Amazonian tree species Sextonia rubra (Lauraceae), we were able both to analyze and to image by tandem MS the molecular products of natural biosynthesis. Despite the low abundance of the metabolites in the wood sample(s), efficient MS/MS analysis of these γ-lactone compounds was achieved, providing high confidence in the identification and localization. In addition, tandem MS imaging minimized the mass interferences and revealed specific localization of these metabolites primarily in the ray parenchyma cells but also in certain oil cells and, further, revealed the presence of previously unidentified γ-lactone, paving the way for future studies in biosynthesis.Fugazza, C., Moesta, A., Pogány, ?., Miklósi, ?., 2018. Presence and lasting effect of social referencing in dog puppies. Animal Behaviour 141, 67-75. referencing is the process by which individuals utilize cues from emotional displays of a social partner to form their response to a new situation. Social referencing can provide advantages, especially to young, inexperienced individuals, by favouring an appropriate reaction to novel situations while avoiding the risks of trial and error learning. While there is evidence for social referencing from humans in adult dogs, Canis familiaris, the ontogeny of this behaviour has not been investigated. Moreover, it is not known whether dogs acquire some information during such interactions and recall it later, when encountering a similar situation. We tested 8-week-old companion dog puppies (N=48) of various breeds by exposing them to a novel stimulus in the presence of human or conspecific social partners. With humans, we tested the effect of different emotional signals expressed by the informant. With conspecifics, we tested whether the presence of the subject's mother or an unfamiliar dog affected behaviour towards the stimulus. Puppies alternated their gaze between the stimulus and the social partner (referential looking) with all the partners. Puppies tested in the presence of a human expressing positive emotional signals towards the stimulus were more likely to approach it than puppies tested with a human expressing neutral emotional signals (behavioural regulation). Importantly, this effect was still apparent after a delay of 1 h, when puppies were tested alone. Puppies tested in the presence of their mother were more likely to approach the stimulus than puppies tested alone or with an unfamiliar dog. The results of this study show that the ability for social referencing develops early in the ontogeny of companion dogs as it is already present at 8 weeks. The valence of the emotional cues provided by a human social partner and the presence of the mother affect the behaviour of puppies exposed to novel situations, even after a delay.Fujii, Y., Angerhausen, D., Deitrick, R., Domagal-Goldman, S., Grenfell, J.L., Hori, Y., Kane, S.R., Pallé, E., Rauer, H., Siegler, N., Stapelfeldt, K., Stevenson, K.B., 2018. Exoplanet biosignatures: Observational prospects. Astrobiology 18, 739-778. hunting efforts have revealed the prevalence of exotic worlds with diverse properties, including Earth-sized bodies, which has fueled our endeavor to search for life beyond the Solar System. Accumulating experiences in astrophysical, chemical, and climatological characterization of uninhabitable planets are paving the way to characterization of potentially habitable planets. In this paper, we review our possibilities and limitations in characterizing temperate terrestrial planets with future observational capabilities through the 2030s and beyond, as a basis of a broad range of discussions on how to advance “astrobiology” with exoplanets. We discuss the observability of not only the proposed biosignature candidates themselves but also of more general planetary properties that provide circumstantial evidence, since the evaluation of any biosignature candidate relies on its context. Characterization of temperate Earth-sized planets in the coming years will focus on those around nearby late-type stars. The James Webb Space Telescope (JWST) and later 30-meter-class ground-based telescopes will empower their chemical investigations. Spectroscopic studies of potentially habitable planets around solar-type stars will likely require a designated spacecraft mission for direct imaging, leveraging technologies that are already being developed and tested as part of the Wide Field InfraRed Survey Telescope (WFIRST) mission. Successful initial characterization of a few nearby targets will be an important touchstone toward a more detailed scrutiny and a larger survey that are envisioned beyond 2030. The broad outlook this paper presents may help develop new observational techniques to detect relevant features as well as frameworks to diagnose planets based on the observables.Fujita, R., Morimoto, S., Umezawa, T., Ishijima, K., Patra, P.K., Worthy, D.E.J., Goto, D., Aoki, S., Nakazawa, T., 2018. Temporal variations of the mole fraction, carbon, and hydrogen isotope ratios of atmospheric methane in the Hudson Bay Lowlands, Canada. Journal of Geophysical Research: Atmospheres 123, 4695-4711. We have conducted simultaneous measurements of the mole fraction and carbon and hydrogen isotope ratios (δ13C and δD) of atmospheric methane (CH4) at Churchill (58°44?N, 93°49'W) in the northern part of the Hudson Bay Lowlands (HBL), Canada, since 2007. Compared with the measurements at an Arctic baseline monitoring station, Ny-?lesund, Svalbard (78°55'N, 11°56?E), CH4 mole fraction is generally higher and δ13C and δD are lower at Churchill due to regional biogenic CH4 emissions. Clear seasonal cycles in the CH4 mole fraction, δ13C, and δD are observable at Churchill, and their seasonal phases in summer are earlier by approximately 2?weeks than those at Ny??lesund. Using the one?box model analysis, the phase difference is ascribed to the different seasonal influence of CH4 emissions from boreal wetlands on the two sites. Short-term CH4 variations are also observed at Churchill throughout the year. The analysis of the observed isotopic signatures of atmospheric CH4 confirmed that the short?term CH4 variations are mainly produced by biogenic CH4 released from the HBL wetlands in summer and by fossil fuel CH4 transported over the Arctic in winter. Forward simulations of an atmospheric chemistry-transport model, with wetland CH4 fluxes prescribed by a process-based model, show unrealistically high CH4 mole fractions at Churchill in summer, suggesting that CH4 emissions assigned to the HBL wetlands are overestimated. Our best estimate of the HBL CH4 emissions is 2.7?±?0.3?Tg?CH4 yr-1 as an average of 2007-2013, consistent with recent estimations by inverse modeling studies.Fulton, J.M., Arthur, M.A., Thomas, B., Freeman, K.H., 2018. Pigment carbon and nitrogen isotopic signatures in euxinic basins. Geobiology 16, 429-445. carbon and nitrogen isotopic signatures of chloropigments and porphyrins from the sediments of redox‐stratified lakes and marine basins reveal details of past biogeochemical nutrient cycling. Such interpretations are strengthened by modern calibration studies, and here, we report on the C and N isotopic composition of pigments and nutrients in the water column and surface sediment of redox‐stratified Fayetteville Green Lake (FGL; New York). We also report δ13C and δ15N values for pyropheophytin a (Pphe a) and bacteriochlorophyll e (Bchl e) deposited in the Black Sea during its transition to a redox‐stratified basin ca. 7.8 ka. We propose a model for evolving nutrient cycling in the Black Sea from 7.8 to 6.4 ka, informed by the new pigment data from FGL. The seasonal study of water column nutrients and pigments at FGL revealed population dynamics in surface and deep waters that were also captured in the sediments. Biomass was greatest near the chemocline, where cyanobacteria, purple sulfur bacteria (PSB), and green sulfur bacteria (GSB) had seasonally variable populations. Bulk organic matter in the surface sediment, however, was derived mainly from the oxygenated surface waters. Surface sediment pigment δ13C and δ15N values indicate intact chlorophyll a (Chl a) was derived from near the chemocline, but its degradation product pheophytin a (Phe a) was derived primarily from surface waters. Bacteriopheophytin a (Bphe a) and Bchl e in the sediments came from chemocline populations of PSB and GSB, respectively. The distinctive δ13C and δ15N values for Chl a, Phe a, and Bphe a in the surface sediment are inputs to an isotopic mixing model that shows their decomposition to a common porphyrin derivative can produce non‐specific sedimentary isotope signatures. This model serves as a caveat for paleobiogeochemical interpretations in basins that had diverse populations near a shallow chemocline. Galushkin, Y.I., Leichenkov, G.L., Dubinin, E.P., 2018. Hydrocarbon generation by the rocks of the Bremer Formation in adjacent areas of the nonvolcanic passive margins of Australia and Antarctica. Geochemistry International 56, 554-565. paper analyzes differences in the history of hydrocarbon (HC) generation by the rocks of the Bremer 1–6 formations in adjacent areas of the nonvolcanic passive continental margins of Australia and Antarctica. The problem is examined by the example of the numerical reconstruction of the burial and thermal history of two sedimentary sequences of approximately equal thicknesses: the section of well 19–2012 in the Bremer sub-basin of the southwestern margin of Australia and the section of pseudowell 2 in the adjacent area of the passive margin of Antarctica on seismic profile 5909 across the Mawson Sea. The asymmetry of Gondwana rifting in the region of interest resulted in asymmetry in the tectonic structure and development of adjacent areas of passive margins and, as a consequence, significantly different histories of HC generation by the rocks of the Bremer 1–6 formations in these areas. Modeling indicates that the rocks of the Bremer 1 and 2 formations are mainly gas-prone in the Bremer basin and can become oil-prone in the Mawson Sea region of the Antarctic margin. In contrast, according to modeling, the rocks of the Bremer 4 and 5 formations generate a minor amount of HC in the well 19–2012 area of the Bremer sub-basin and considerable amounts of heavy and light oil in the adjacent Antarctic margin area at pseudowell 2 in the Mawson Sea. Original Russian Text ? Yu.I. Galushkin, G.L. Leichenkov, E.P. Dubinin, 2018, published in Geokhimiya, 2018, No. 6, pp. 559–571.Ganesh Saratale, R., Kumar, G., Banu, R., Xia, A., Periyasamy, S., Dattatraya Saratale, G., 2018. A critical review on anaerobic digestion of microalgae and macroalgae and co-digestion of biomass for enhanced methane generation. Bioresource Technology 262, 319-332. production using algal resources has been widely studied as a green and alternative renewable technology. This review provides an extended overview of recent advances in biomethane production via direct anaerobic digestion (AD) of microalgae, macroalgae and co-digestion mechanism on biomethane production and future challenges and prospects for its scaled-up applications. The effects of pretreatment in the preparation of algal feedstock for methane generation are discussed briefly. The role of different operational and environmental parameters for instance pH, temperature, nutrients, organic loading rate (OLR) and hydraulic retention time (HRT) on sustainable methane generation are also reviewed. Finally, an outlook on the possible options towards the scale up and enhancement strategies has been provided. This review could encourage further studies in this area, to intend and operate continuous mode by designing stable and reliable bioreactor systems and to analyze the possibilities and potential of co-digestion for the promotion of algal-biomethane technology.Gao, Y., Yang, M., Zheng, J.-n., Chen, B., 2018. Production characteristics of two class water-excess methane hydrate deposits during depressurization. Fuel 232, 99-107. are four main classes of methane hydrate deposits in nature. These classes differ in their distributions of the methane hydrate layer, free water layer and free gas layer. The gas production rate, water production rate, gas-to-water ratio, gas and water production recovery during the depressurization dissociation process are different for hydrate samples of different classes. Water-excess hydrate samples of Classes 2 and 3 were prepared in the present work, and they were dissociated at 2.0?MPa, 2.3?MPa, 2.6?MPa and 3.0?MPa. Ice formation was observed when the backpressure was 2.0?MPa. The gas-to-water ratio for Class 3 samples was higher than that of Class 2 samples, regardless of the backpressure. The average gas production rate for the 90% overall gas amount of Class 2 samples was higher than that of Class 3 samples for a backpressure of 2.0?MPa, whereas the opposite result was found for backpressures equal to or greater than 2.3?MPa. Furthermore, the water recovery value of Class 2 samples was higher than that of Class 3 samples by approximately 10%, and the gas recovery value of Class 2 samples was lower than that of Class 3 samples by approximately 20% at the same backpressure. These experiments provided some basic data for the exploitation of Class 2 and Class 3 deposits and find out the influence of backpressure on methane hydrate dissociation of the two class deposits by depressurization.Gao, Z., Guéguen, C., 2018. Distribution of thiol, humic substances and colored dissolved organic matter during the 2015 Canadian Arctic GEOTRACES cruises. Marine Chemistry 203, 1-9. sulfur and humics play a key role in the biogeochemistry of metals in natural waters but their distribution is not well understood. In this study, we measured the concentrations of thiol-like, humic substance (HS) -like and fluorescent dissolved organic matter (FDOM) during the 2015 Canadian Arctic GEOTRACES cruises in the Canada Basin and Canadian Arctic Archipelago (CAA). Concentrations of thiol-like (7–85?nM, expressed as equivalent to glutathione concentration) and HS-like (19 to 190?μg C/L) determined by cathodic stripping voltammetry (CSV) were congruent with previous marine CSV-based studies. Three humic-like (C1-C3) and one protein-like (C4) components identified and validated using excitation-emission matrix (EEM) and parallel factor analysis (PARAFAC) have been reported in previous ocean studies. The distributions of HS-like and humic-like components (C1 and C2) in the CAA were similar, whereas thiol-like and protein-like component C4 were closely related in the study area. Maximum CSV-based thiol-like levels were associated with chlorophyll-a maximum, confirming the biogenic origin of thiols. The distribution and concentrations of CSV-based thiol- and HS-like, and FDOM varied between four distinct water masses (i.e. surface waters, Arctic outflow waters, Arctic intermediate waters and North Atlantic deep waters) with the lowest levels associated with the surface waters, likely due to photobleaching and sea ice melt dilution. The concentrations in CSV-based HS-like and FDOM in the Arctic outflow waters decreased from western to eastern CAA, reflecting the influence of DOM-rich Pacific derived waters.Ge, X., Liu, J., Fan, Y., Xing, D., Deng, S., Cai, J., 2018. Laboratory investigation into the formation and dissociation process of gas hydrate by low‐field NMR technique. Journal of Geophysical Research: Solid Earth 123, 3339-3346. We monitored the gas hydrate through low?field nuclear magnetic resonance measurement. An observed decrease of the relaxation time (T2) intensity corresponds to the formation process, whereas an increase of the intensity corresponds to the dissociation process. The right domain of the spectrum with T2 larger than 10?ms disappears gradually with the formation time, whereas the left domain with T2 smaller than 1?ms remains invariant, indicating the gas hydrate forms preferentially in larger pores. In addition, the right domain increases rapidly with the dissociation time, revealing that the gas hydrate preferentially decomposes in large pores. The spectrum distributions move toward the fast relaxation domain with the growth of gas hydrate, because the generated gas hydrate occupies the large pore and accelerate the relaxation rate. There is no obvious relationship between the gas hydrate saturation and the porosity, whereas the volume and preliminary dissociation ratio are strongly correlated with the porosity.Geng, L., Li, G., Wang, M., Li, Y., Tian, S., Pang, W., Lyu, Z., 2018. A fractal production prediction model for shale gas reservoirs. Journal of Natural Gas Science and Engineering 55, 354-367. production forecasting model for shale gas reservoirs is proposed based on the continuum medium theory (organic/inorganic matrix) and discrete fracture model (fracture system). The fractal property of the pore size distribution of shale matrix is considered. The stability and accuracy of the model are successfully validated with the field data. Variations of different flow mechanisms during the exploitation of shale gas are investigated. The sensitivities of gas production to the pore size distribution of shale matrix, natural fracture parameters and hydraulic fracture parameters are analyzed. Our results show that: (1) The contribution of the convective flow and surface diffusion to total gas flow increases with the depletion of shale gas, while that of the bulk diffusion and Knudsen diffusion decreases gradually. (2) Among the fractal pore-size parameters, the maximum inorganic pore diameter has the most significant impact on the cumulative gas production of up to 13.9%. (3) After the natural fracture number increases to a certain extent, gas production increases slowly even if more natural fractures exist in the reservoir. The complex fracture network is beneficial to increase shale gas production. (4) The cumulative gas production rises as the increase of the hydraulic fracture half-length, flow conductivity, spacing and number. The rapid production rate in the early production stage may result in a fast reservoir energy depletion, which has a negative effect on production.Genovese, C., Grotti, M., Pittaluga, J., Ardini, F., Janssens, J., Wuttig, K., Moreau, S., Lannuzel, D., 2018. Influence of organic complexation on dissolved iron distribution in East Antarctic pack ice. Marine Chemistry 203, 28-37. Antarctic sea ice covers an area larger than the Antarctic continent itself, the discovery that it can fertilize the Southern Ocean with iron (Fe) has fostered a new breadth of research in recent years. In order to test the hypothesis that Fe-binding organic ligands control the distribution of dissolved iron (DFe) in Antarctic pack ice, iron organic speciation was investigated in samples collected during the Sea Ice Physics and Ecosystem eXperiment-2 (SIPEX-2) voyage in Austral winter/spring 2012. Dissolved Fe was measured using sector field inductively coupled plasma mass spectrometry, and iron organic speciation parameters were determined by competitive ligand equilibration - adsorptive cathodic stripping voltammetry method, using 1-nitroso-2-naphthol (NN) as the added ligand. The concentration of Fe-binding organic ligands (Lt) ranged from 4.9?nM to 41?nM (average of 14.9?±?8.4?nM, n?=?34), and was always higher than the corresponding DFe (average of 7.5?±?4.5?nM, n?=?34). Conditional stability constants (log K′Fe’L?=?11.7–13.0) were similar to those previously observed in land-fast ice. Concentrations of DFe and Lt displayed similar depth profiles; their strong correlation (Spearman's ρ?=?0.80, p?<?0.001) suggested that Fe-binding organic ligands control DFe distribution in Antarctic pack ice. Unlike results previously obtained for land-fast ice, Fe-binding organic ligands in pack ice were never saturated with iron (Lt/DFe?>?1). Estimates showed that pack ice would have released 0.45?μmol/m2/d of Lt during spring melt, 0.21?μmol/m2/d of which are free from Fe binding, and hence available for further complexation. Therefore, it is suggested that this excess of Fe-free ligands may play a key role in controlling the solubility of free or newly formed Fe in surface waters before the peak of primary production, outcompeting the Fe-binding organic ligands already present in seawater.Gess, R., Ahlberg, P.E., 2018. A tetrapod fauna from within the Devonian Antarctic Circle. Science 360, 1120-1124.: Until now, all known fossils of tetrapods (limbed vertebrates with digits) and near-tetrapods (such as Elpistostege, Tiktaalik, and Panderichthys) from the Devonian period have come from localities in tropical to subtropical paleolatitudes. Most are from Laurussia, a continent incorporating Europe, Greenland, and North America, with only one body fossil and one footprint locality from Australia representing the southern supercontinent Gondwana. Here we describe two previously unknown tetrapods from the Late Devonian (late Famennian) Gondwana locality of Waterloo Farm in South Africa, then located within the Antarctic Circle, which demonstrate that Devonian tetrapods were not restricted to warm environments and suggest that they may have been global in distribution.Editor's Summary. Out of Antarctica: When we think of Devonian tetrapods, the ancestors of all modern vertebrates, we tend to picture amphibian-like creatures emerging from the water into a wet tropical forest or swamp. Indeed, all previously described specimens of this group have been recovered from the tropics. Gess and Ahlberg now describe two fossil tetrapods from Devonian Antarctica. Thus, the distribution of tetrapods may have been global, which encourages us to rethink the environments in which this important group was shaped.Gibson, G.M., Champion, D.C., Withnall, I.W., Neumann, N.L., Hutton, L.J., 2018. Assembly and breakup of the Nuna supercontinent: Geodynamic constraints from 1800 to 1600?Ma sedimentary basins and basaltic magmatism in northern Australia. Precambrian Research 313, 148-169. formation from 1800 to 1640?Ma in northern Australia took place in a backarc extensional upper plate setting accompanied by lithospheric thinning and voluminous but episodic basaltic magmatism. West-dipping subduction combined with oceanward retreat of an associated magmatic arc drove these processes and commenced after the separation of Laurentia, precluding any connection with eastern Australia from 1800?Ma until basin closure and re-accretion of the arc ca. 1650–1640?Ma. Early rift-related basaltic magmatism generated km-thick piles of interstratified 1785–1775?Ma shallow-water sediment and tholeiitic lava whose low- and high-Ti compositions bear some resemblance to basalts erupted during the earlier stages of Gondwana breakup. Later basalts evolved in a western Pacific-style marginal marine basin and exhibit compositions consistent with melting of a subcontinental mantle source that had either been metasomatically altered during flat-slab subduction or contaminated with crustal material during an earlier subduction-related event. From 1700 to 1670?Ma, the crust and underlying lithospheric mantle rapidly thinned, and basaltic magmatism increasingly occurred in a turbidite-dominated deep marine environment with concomitant changes towards more subdued subduction-related signatures in the east and less enrichment in incompatible elements. Coincidently, granites emplaced from 1780 to 1670?Ma at deeper crustal levels were extensionally unroofed along with their country rocks. Backarc extension concluded no later than 1655?Ma by which time MORB-like magmas were being sourced directly from the asthenosphere and northern Australia had transitioned from an active to passive continental margin lying along the inboard side of the marginal sea. With ongoing subduction and consumption of oceanic crust to the east, Laurentia began to encroach upon both the arc and Australian margin, resulting initially in collapse of the backarc basin and then continent–continent collision by ca. 1620?Ma. These events represent an important milestone in assembly of the Nuna supercontinent and mark the end of one complete Wilson cycle from the time that the two continents first separated until their re-amalgamation 150?Myr later. Timeframes for the opening and closure of ocean basins in southern Laurentia are similar, raising the possibility that the same convergent margin and backarc extensional processes may once have extended along strike into ancestral North America.Gilleaudeau, G.J., Voegelin, A.R., Thibault, N., Moreau, J., Ullmann, C.V., Klaebe, R.M., Korte, C., Frei, R., 2018. Stable isotope records across the Cretaceous-Paleogene transition, Stevns Klint, Denmark: New insights from the chromium isotope system. Geochimica et Cosmochimica Acta 235, 305-332. Cretaceous to Early Paleogene time represents a critical transitional period in Earth history. Global events include short-term instability in climate and ocean circulation, large igneous province emplacement, and catastrophic extinction of marine and terrestrial fauna due at least in part to a bolide impact event. The response of the ocean system to Cretaceous-Paleogene (K-Pg) global events has been the subject of much research, yet fundamental questions remain regarding carbon cycling, climate, ocean mixing, and redox conditions. To help elucidate paleoceanographic changes across the K-Pg transition, we revisit the classic Maastrichtian to Danian chalk-limestone succession at Stevns Klint, Denmark with a suite of new geochemical data, including insights from the redox-sensitive chromium isotope system. We use carbon and oxygen isotope trends to form a well-constrained framework for the succession, before presenting strontium isotope, chromium isotope, and rare-earth element data for the units deposited both before and after the K-Pg event. Carbon isotopes show only minor perturbation across the K-Pg boundary and oxygen isotopes record a prominent positive excursion, with both of these trends standing in contrast to many K-Pg boundary sections worldwide. Strontium isotopes record a spike towards more radiogenic values, which is consistent with a globally-observed, short-term weathering pulse. The chromium isotope profile of Maastrichtian chalk begins with strongly positive values followed by a sharp negative excursion associated with a facies shift and initiation of bottom currents in the Chalk Sea. δ53Cr values then recover, before falling steadily across the K-Pg boundary and into the Danian limestone. Chromium isotope trends do not correspond to changes in hydrothermal input or basin redox conditions—instead, we propose that mixing of water masses with distinct chromium isotope signatures controlled temporal chromium isotope variability. The local mixing event inferred from our Maastrichtian chromium isotope data could be related to a temporary inflow of Tethyan bottom waters, or the shift from end-Maastrichtian greenhouse warming (associated with Deccan volcanism) to the worldwide cooling phase that immediately preceded the K-Pg boundary. No immediate change in chromium isotopes is recorded across the K-Pg boundary, indicating that the bolide impactor did not substantially perturb the marine chromium cycle, at least at the scale resolvable by our data. Instead, chromium isotope trends continued to be controlled by local oceanographic processes, highlighting the potential of the chromium isotope system to record isotopic heterogeneity and mixing events in ancient oceans.Giraldo-Gómez, V.M., Beik, I., Podlaha, O.G., Mutterlose, J., 2018. A paleoenvironmental analyses of benthic foraminifera from Upper Cretaceous – Lower Paleocene oil shales of Jordan. Cretaceous Research 91, 1-13. study is based on Maastrichtian and Danian oil shales of a cored well located in the Jafr Basin in central Jordan. Studied sedimentary rocks consist of alternations of monotonous bituminous marls, phosphatized marls, occasional dolomite, black chert, and limestone concretions. The main characteristics of these deposits are the high values of the total organic carbon (TOC) which fluctuate between 2.8 and 32.1 wt%. Benthic foraminifera were studied quantitatively in order to reconstruct environmental changes across the Maastrichtian and early Danian. Three clusters of benthic foraminifera, showing different assemblage compositions on the species level, were distinguished. Each of these assemblages is characterized by changes of diversity indices and abundances, indicating fluctuations of the bottom water oxygenation and organic matter fluxes. Water-depth preferences based on three associations and marker species of benthic foraminifera indicate an estimated paleodepth from middle to outer neritic (～50–200 m) during the Maastrichtian and Danian.During the Maastrichtian, Anomalinoides praeacutus is the dominant benthic foraminifera species characterized by high abundances. A short decline of A. praeacutus, observed in calcareous nannofossil > biozone UC18/19 (lower Maastrichtian), is compensated by an increase of Anomalinoides umboniferus. Abundance fluctuations of benthic foraminifera included in the Buliminacea (Sitella fabilis, Elhasaella alanwoodi, Neobulimina canadensis, Reussella aegyptiaca) are recorded from the assemblages. The taxonomic composition of the assemblages and the varying TOC values indicate low oxygen bottom-water conditions under high organic flux across the Maastrichtian. A moderate change is documented for the Danian, where A. praeacutus continues to dominate the assemblages, but Siphogenerinoides eleganta and Uvigerinella spp. are less common. These benthic associations along with a decrease of the TOC content suggest a gentle increase of the bottom water oxygenation with moderate organic fluxes.Girotto, G., China, S., Bhandari, J., Gorkowski, K., Scarnato, B.V., Capek, T., Marinoni, A., Veghte, D.P., Kulkarni, G., Aiken, A.C., Dubey, M., Mazzoleni, C., 2018. Fractal-like tar ball aggregates from wildfire smoke. Environmental Science & Technology Letters 5, 360–365. balls are atmospheric particles that are abundant in slightly aged biomass burning smoke and have a significant, but highly uncertain, role in Earth’s radiative balance. Tar balls are typically detected using electron microscopy and generally, they are observed as individual spheres. Here, we report new observations of a significant fraction of tar ball aggregates (～27% by number) from samples collected in a plume of the Whitewater-Baldy Complex fire in New Mexico. The structure of these aggregates is fractal-like and follows a scale invariant power law similar to that of soot particles, despite the considerably larger size and smaller number of monomers. We also present observations of tar ball aggregates from four other geographical locations, including a remote high-elevation site in the North Atlantic Ocean. Aggregation affects the particle optical properties and, therefore, their climatic impact. We performed numerical simulations based on the observed morphology and estimated the effects of aggregation on the optical properties of the tar balls. On the basis of single-particle numerical simulations, we find that aggregates had a single scattering albedo up to 41% and 23% higher than that of individual tar balls at 550 nm and 350 nm, respectively.Giuliani, A., Williams, J.P., Green, M.R., 2018. Extreme ultraviolet radiation: A means of ion activation for tandem mass spectrometry. Analytical Chemistry 90, 7176-7180. mass spectrometry has long been established as a corner stone of analytical and structural chemistry. Fast radical-directed dissociation, produced by electron-transfer and electron-capture dissociation (ETD and ECD) has been shown to provide important complementary information to collision-induced dissociation (CID). We report the first application of extreme-ultraviolet (XUV) lamps to tandem mass spectrometry. These discharge lamps are versatile, robust, and low-cost sources of energetic photons (40–80 nm). The coupling of the discharge lamp with a Waters Synapt G2-Si Q-ToF mass spectrometer is achieved through a specific trapping scheme in the TriWave region of the instrument, allowing efficient irradiation of the precursor ions. Rich radical-directed dissociation was produced for a number of model compounds, providing unique, complementary information to existing dissociation techniques.Goedert, J., Lécuyer, C., Amiot, R., Arnaud-Godet, F., Wang, X., Cui, L., Cuny, G., Douay, G., Fourel, F., Panczer, G., Simon, L., Steyer, J.S., Zhu, M., 2018. Euryhaline ecology of early tetrapods revealed by stable isotopes. Nature 558, 68-72. fish-to-tetrapod transition—followed later by terrestrialization—represented a major step in vertebrate evolution that gave rise to a successful clade that today contains more than 30,000 tetrapod species. The early tetrapod Ichthyostega was discovered in 1929 in the Devonian Old Red Sandstone sediments of East Greenland (dated to approximately 365 million years ago). Since then, our understanding of the fish-to-tetrapod transition has increased considerably, owing to the discovery of additional Devonian taxa that represent early tetrapods or groups evolutionarily close to them. However, the aquatic environment of early tetrapods and the vertebrate fauna associated with them has remained elusive and highly debated. Here we use a multi-stable isotope approach (δ13C, δ18O and δ34S) to show that some Devonian vertebrates, including early tetrapods, were euryhaline and inhabited transitional aquatic environments subject to high-magnitude, rapid changes in salinity, such as estuaries or deltas. Euryhalinity may have predisposed the early tetrapod clade to be able to survive Late Devonian biotic crises and then successfully colonize terrestrial environments.Goh, B., Kim, J., Seo, S., Kim, T.-Y., 2018. High-throughput measurement of lipid turnover rates using partial metabolic heavy water labeling. Analytical Chemistry 90, 6509-6518. analytical platforms for high-throughput determination of lipid turnover in vivo have been developed based on partial metabolic 2H2O labeling. The performance on lipid kinetics measurement of our methods was validated in three different liquid chromatography–mass spectrometry (LC-MS) setups: MS-only, untargeted MS/MS, and targeted MS/MS. The MS-only scheme consisted of multiple LC-MS runs for quantification of lipid mass isotopomers and an extra LC-MS/MS run for lipid identification. The untargeted MS/MS format utilized multiple data-dependent LC-MS/MS runs for both quantification of lipid mass isotopomers and lipid identification. An in-house software was also developed to streamline the data processing from peak area quantification of mass isotopomers to exponential curve fitting for extracting the turnover rate constant. With HeLa cells cultured in 5% 2H2O media for 48 h, we could deduce the species-level turnover rates of 108 and 94 lipids in the MS-only and untargeted MS/MS schemes, respectively, which covers 13 different subclasses and spans 3 orders of magnitude. Furthermore, the targeted MS/MS setup, which performs scheduled LC-MS/MS experiments for some targeted lipids, enabled differential measurement between the turnover rates of the head and tail groups of lipid. The reproducibility of our lipid kinetics measurement was also demonstrated with lipids that commonly detected in both positive and negative ion modes or in two different adduct forms.Gong, D., Li, J., Ablimit, I., He, W., Lu, S., Liu, D., Fang, C., 2018. Geochemical characteristics of natural gases related to Late Paleozoic coal measures in China. Marine and Petroleum Geology 96, 474-500. 2013, more than 20 gas fields related to Late Paleozoic coal measures have been discovered in China, primarily distributed in the Bohai Bay, Ordos, Sichuan, and Junggar Basins. The total proven reserve in these gas fields is more than 3200?×?109?m3, accounting for 30.1% of the proven gas reserves in China. After analyzing the molecular compositions, stable carbon isotopes, and helium isotopes of 375 gas samples, genetic types and origins of the natural gas, as well as the secondary alterations it experienced, are discussed in this study. Most of the natural gas related to the Late Paleozoic coal measures are coal-type gas, with some of the gases from the Sichuan Basin and the Jingbian gas field in the Ordos Basin being oil-type gases generated from marine mudstones in the Permian Longtan Formation and marine carbonates in the Ordovician Majiagou Formation, respectively. The equivalent vitrinite reflectance values based on stable carbon isotopes of natural gases vary from 0.8% to 2.5%, indicating the mature to over mature stage. Positive carbon isotope series (δ13C-CH4?<?δ13C-C2H6?<?δ13C-C3H8) are observed in most gas samples, and carbon isotope reversals occur in the forms of δ13C-CH4?>?δ13C-C2H6 and δ13C-CH4?<?δ13C-C2H6?>?δ13C-C3H8. The form of δ13C-CH4?>?δ13C-C2H6 is primarily resulted from the mixing of oil-type gases of different maturities, while the form of δ13C-CH4?<?δ13C-C2H6?>?δ13C-C3H8 is primarily resulted from the mixing of coal-type gases of different maturities. High concentrations of hydrogen sulfide in natural gas from the Sichuan Basin and the Chenghai gas field in the Bohai Bay Basin are resulted from thermochemical sulfate reduction (TSR), which causes, to some extent, the fractionation of carbon isotopes. By contrast, the fractionation of methane carbon isotopes resulting from the TSR effect is not clear. Carbon dioxide from the Bohai Bay and Junggar Basins is primarily biogenic, generated via the thermal decomposition of organic matter, while that from the Ordos Basin, Sichuan Basin, and Chenghai gas field is generated via the thermal decomposition of carbonates. Carbon dioxide related to the TSR effect has also contributed to the Sichuan Basin and Chenghai gas field.Gong, X., Garcia-Robledo, E., Lund, M.B., Lehner, P., Borisov, S.M., Klimant, I., Revsbech, N.P., Schramm, A., 2018. Gene expression of terminal oxidases in two marine bacterial strains exposed to nanomolar oxygen concentrations. FEMS Microbiology Ecology 94, Article fiy072. final step of aerobic respiration is carried out by a terminal oxidase transporting electrons to oxygen (O2). Prokaryotes harbor diverse terminal oxidases that differ in phylogenetic origin, structure, biochemical function, and affinity for O2. Here we report on the expression of high-affinity (cytochrome cbb3 oxidase), low-affinity (cytochrome aa3 oxidase), and putative low-affinity (cyanide-insensitive oxidase (CIO)) terminal oxidases in the marine bacteria Idiomarina loihiensis L2-TR and Marinobacter daepoensis SW-156 upon transition to very low O2 concentrations (<200 nM), measured by RT-qPCR. In both strains, high-affinity cytochrome cbb3 oxidase showed the highest expression levels and was significantly up-regulated upon transition to low O2 concentrations. Low-affinity cytochrome aa3 oxidase showed very low transcription levels throughout the incubation. Surprisingly, however, it was also up-regulated upon transition to low O2 concentrations. In contrast, putative low-affinity CIO had much lower expression levels and markedly different regulation patterns between the two strains. These results demonstrate that exposure to low O2 concentrations regulates the gene expression of different types of terminal oxidases, but also that the type and magnitude of transcriptional response is species-dependent. Therefore, in situ transcriptome data cannot, without detailed knowledge of the transcriptional regulation of the species involved, be translated into relative respiratory activity.Gonzalez-Gil, L., Mauricio-Iglesias, M., Carballa, M., Lema, J.M., 2018. Why are organic micropollutants not fully biotransformed? A mechanistic modelling approach to anaerobic systems. Water Research 142, 115-128. of most organic micropollutants (OMPs) during wastewater treatment is not complete and an unexplained steady decrease of the biotransformation rate with time is reported for many OMPs in different biological processes. To minimize and accurately predict the emission of OMPs into the environment, the mechanisms and limitations behind their biotransformations should be clarified. Aiming to achieve this objective, the present study follows a mechanistic modelling approach, based on the formulation of four models according to different biotransformation hypotheses: Michaelis-Menten kinetics, chemical equilibrium between the parent compound and the transformation product (TP), enzymatic inhibition by the TP, and a limited compound bioavailability due to its sequestration in the solid phase. These models were calibrated and validated with kinetic experiments performed in two different anaerobic systems: continuous reactors enriched with methanogenic biomass and batch assays with anaerobic sludge. Model selection was conducted according to model suitability criteria (goodness of fitting the experimental data, confidence of the estimated parameters, and model parsimony) but also considering mechanistic evidences. The findings suggest that reversibility of the biological reactions and/or sequestration of compounds are likely the causes preventing the complete biotransformation of OMPs, and biotransformation is probably limited by thermodynamics rather than by kinetics. Taking into account its simplicity and broader applicability spectrum, the reversible biotransformation is the proposed model to explain the incomplete biotransformation of OMPs.González-Nicolás, A., Baù, D., Cody, B.M., 2018. Application of binary permeability fields for the study of CO2 leakage from geological carbon storage in saline aquifers of the Michigan Basin. Mathematical Geosciences 50, 525-547. feasibility of geological carbon storage (GCS) sites depends on their capacity to retain safely CO2. While deep saline formations and depleted gas/oil reservoirs are good candidates to sequester $${\hbox {CO}_{2}}$$ CO 2 , gas/oil reservoirs typically have a limited storage capacity compared to ideal targets ( ～ ?1?Mt/year) considered for CO2 disposal (Celia et al. in Water Resour Res 51(9):6846–6892, 2015. doi: 10.1002/2015WR017609 ). In this respect, deep saline aquifers are considered more appropriate formations for GCS, but present the disadvantage of having limited characterization data. In particular, information about the continuity of the overlying sealing formations (caprock) is often sparse if it exists at all. In this work, a study of CO2 leakage is conducted for a candidate GCS site located in the Michigan Basin, whose sealing properties of the caprock are practically unknown. Quantification of uncertainty on CO2 leakage from the storage formation is achieved through a Monte Carlo simulation approach, relying on the use of a computationally efficient semi-analytical leakage model based upon the solution derived by Nordbotten et al. (Environ Sci Technol 43(3):743–749, 2009), which assumes leakage occurs across “passive” wells intersecting caprock layers. A categorical indicator Kriging simulator is developed and implemented to represent the caprock sealing properties and model the permeability uncertainty. Binary fields of caprock permeability are generated and exhibit mostly low permeability, with sparsely-occurring local high permeability areas where brine and CO2 may leak out of the storage formation. In addition, the feasibility of extending the use of the semi-analytical model to large-area leakage pathways is studied. This work advances a methodology for preliminary uncertainty quantification of CO2 leakage at sites of GCS with little or no information on the ealing properties of the caprock. The implemented analysis shows that, for the considered site, CO2 leakage may not be negligible even for relatively low (～ ?1%) probabilities of finding permeable inclusions in the caprock and highlights the importance of being able to characterize caprock sealing properties over large areas.Goswami, R., Chaturvedi, K.R., Kumar, R.S., Chon, B.H., Sharma, T., 2018. Effect of ionic strength on crude emulsification and EOR potential of micellar flood for oil recovery applications in high saline environment. Journal of Petroleum Science and Engineering 170, 49-61. flooding is one of the chemical oil recovery techniques in which micelle action emulsifies the crude oil to be mobilized in form of emulsion from a subsurface porous media. However, the subsurface conditions such as high ionic strength and temperature are challenges to the successful use of micellar flood owing to the deterioration of micelle action suggesting no crude emulsification. The ionic compounds dissociate into different ions that may further affect micelle action via loss in viscosity and pressure drop, increased water cut, and mobility contrast between micellar flood and displaced oil. Thus, investigation leading to the successful use of micellar flood, context to crude emulsion, in extreme salinity and temperature is vital to extend the use of chemical methods in new reservoirs. In this work, a typical surfactant sodium dodecyl sulfate (SDS) solution with critical micelle concentration (0.8?wt%) was tested to emulsify a fresh crude oil in the presence of varying ionic strength (0–4?wt%, NaCl/CaCl2 and temperature (40–98?°C). The efficacy of SDS micelles to produce crude emulsion significantly reduced with increasing salt concentration as reported through microscopic, rheological, and flooding experiments, particularly for divalent salt (CaCl2) than monovalent salt (NaCl). The increase in temperature (>40?°C) further curtailed the growth of crude emulsion, mainly due to enhanced droplet coalescence; thus the use of micellar flood is critical in a reservoir enriched with high salinity and high temperature. Salinity effect on emulsion viscosity is reported through rheological measurements. The study highlighted important aspects of surfactant flooding and is a forward step towards the use of SDS based micellar flood at complex reservoir conditions.Graham, E.B., Crump, A.R., Kennedy, D.W., Arntzen, E., Fansler, S., Purvine, S.O., Nicora, C.D., Nelson, W., Tfaily, M.M., Stegen, J.C., 2018. Multi 'omics comparison reveals metabolome biochemistry, not microbiome composition or gene expression, corresponds to elevated biogeochemical function in the hyporheic zone. Science of The Total Environment 642, 742-753. hotspots are pervasive at terrestrial-aquatic interfaces, particularly within groundwater-surface water mixing zones (hyporheic zones), and they are critical to understanding spatiotemporal variation in biogeochemical cycling. Here, we use multi 'omic comparisons of hotspots to low-activity sediments to gain mechanistic insight into hyporheic zone organic matter processing. We hypothesized that microbiome structure and function, as described by metagenomics and metaproteomics, would distinguish hotspots from low-activity sediments by shifting metabolism towards carbohydrate-utilizing pathways and elucidate discrete mechanisms governing organic matter processing in each location. We also expected these differences to be reflected in the metabolome, whereby hotspot carbon (C) pools and metabolite transformations therein would be enriched in sugar-associated compounds. In contrast to expectations, we found pronounced phenotypic plasticity in the hyporheic zone microbiome that was denoted by similar microbiome structure, functional potential, and expression across sediments with dissimilar metabolic rates. Instead, diverse nitrogenous metabolites and biochemical transformations characterized hotspots. Metabolomes also corresponded more strongly to aerobic metabolism than bulk C or N content only (explaining 67% vs. 42% and 37% of variation respectively), and bulk C and N did not improve statistical models based on metabolome composition alone. These results point to organic nitrogen as a significant regulatory factor influencing hyporheic zone organic matter processing. Based on our findings, we propose incorporating knowledge of metabolic pathways associated with different chemical fractions of C pools into ecosystem models will enhance prediction accuracy.Gras, R., Luong, J., Haddad, P.R., Shellie, R.A., 2018. Gas chromatography with simultaneous detection: Ultraviolet spectroscopy, flame ionization, and mass spectrometry. Journal of Chromatography A 1563, 171-179. effective analytical strategy was developed and implemented to exploit the synergy derived from three different detector classes for gas chromatography, namely ultraviolet spectroscopy, flame ionization, and mass spectrometry for volatile compound analysis. This strategy was achieved by successfully hyphenating a user-selectable multi-wavelength diode array detector featuring a positive temperature coefficient thermistor as an isothermal heater to a gas chromatograph. By exploiting the non-destructive nature of the diode array detector, the effluent from the detector was split to two parallel detectors; namely a quadrupole mass spectrometer and a flame ionization detector.This multi-hyphenated configuration with the use of three detectors is a powerful approach not only for selective detection enhancement but also for improvement in structural elucidation of volatile compounds where fewer fragments can be obtained or for isomeric compound analysis. With the diode array detector capable of generating high resolution gas phase spectra, the information collected provides useful confirmatory information without a total dependence on the chromatographic separation process which is based on retention time. This information-rich approach to chromatography is achieved without incurring extra analytical time, resulting in improvements in compound identification accuracy, analytical productivity, and cost. Chromatographic performance obtained from model compounds was found to be acceptable with a relative standard deviation of the retention times of less than 0.01% RSD, and a repeatability at two levels of concentration of 100 and 1000 ppm (v/v) of less than 5% (n = 10).With this configuration, correlation of data between the three detectors was simplified by having near identical retention times for the analytes studied.Gras, R., Luong, J., Pursch, M., Shellie, R.A., 2018. Positive temperature coefficient compensating heating for analytical devices. Analytical Chemistry 90, 6426-6430. temperature coefficient thermistors acting as heating devices are quickly growing in popularity and are being adapted into critical applications in many sectors from medical to space discovery. Positive temperature coefficient heating offers substantial benefits for miniaturized and portable analytical devices in key aspects such as energy efficiency, safety in overheating, size, scalability, and in discovering new thermal management strategies. These heaters can reach 230 °C without additional requirements for regulating electronics. By incorporating positive temperature coefficient technology into a commercial diode array photometric detector, the detector is made suitable for coupling with gas chromatography. The detector cartridge flow cell is heated to a specific target temperature within the range of 70 to 150 °C without impacting the detector’s construction material or imparting any negative effect to the surrounding detector system electronics. Applying a temperature of 150 °C to the cell permits analysis of volatile and semivolatile compounds with a boiling point equivalent to that of n-hexadecene (285 °C). Model compounds of alkene homologues from C8 to C16 showed a maximum peak asymmetry of 1.10 with the heated cell design. A high degree of repeatability was observed with RSD of less than 0.01% in retention time and 3% in peak area (n = 10).Greig, K., Gosling, A., Collins, C.J., Boocock, J., McDonald, K., Addison, D.J., Allen, M.S., David, B., Gibbs, M., Higham, C.F.W., Liu, F., McNiven, I.J., O’Connor, S., Tsang, C.H., Walter, R., Matisoo-Smith, E., 2018. Complex history of dog (Canis familiaris) origins and translocations in the Pacific revealed by ancient mitogenomes. Scientific Reports 8, Article 9130. evidence suggests that dogs were introduced to the islands of Oceania via Island Southeast Asia around 3,300 years ago, and reached the eastern islands of Polynesia by the fourteenth century AD. This dispersal is intimately tied to human expansion, but the involvement of dogs in Pacific migrations is not well understood. Our analyses of seven new complete ancient mitogenomes and five partial mtDNA sequences from archaeological dog specimens from Mainland and Island Southeast Asia and the Pacific suggests at least three dog dispersal events into the region, in addition to the introduction of dingoes to Australia. We see an early introduction of dogs to Island Southeast Asia, which does not appear to extend into the islands of Oceania. A shared haplogroup identified between Iron Age Taiwanese dogs, terminal-Lapita and post-Lapita dogs suggests that at least one dog lineage was introduced to Near Oceania by or as the result of interactions with Austronesian language speakers associated with the Lapita Cultural Complex. We did not find any evidence that these dogs were successfully transported beyond New Guinea. Finally, we identify a widespread dog clade found across the Pacific, including the islands of Polynesia, which likely suggests a post-Lapita dog introduction from southern Island Southeast Asia.Gross, D., Sachsenhofer, R.F., Bechtel, A., Gratzer, R., Grundtner, M.L., Linzer, H.G., Misch, D., Pytlak, L., Scheucher, L., 2018. Petroleum systems in the Austrian sector of the North Alpine Foreland Basin: An overview. Journal of Petroleum Geology 41, 299-317. separate petroleum systems have been identified in the Austrian sector of the North Alpine Foreland Basin: a lower Oligocene – Cenomanian/Eocene oil and thermogenic gas system; and an Oligocene‐Miocene microbial gas system. Recent studies by both academic and industry‐based research groups have resulted in an improved understanding of these petroleum systems, which are reviewed in this paper. Lower Oligocene organic‐rich intervals (up to 12 %TOC; HI: 400–600 mgHC/gTOC), capable of generating slightly more than 1 t of hydrocarbons/m2, are the source rocks for the thermogenic petroleum system in the Austrian sector of the North Alpine Foreland Basin. The present‐day distribution of this source rock is controlled by submarine mass movements which removed a large part of the organic‐rich interval from its depositional location during the late early Oligocene. The transported material was redeposited in locations to the south which are at the present day buried beneath Alpine thrust sheets. In addition, source rock units were incorporated into Molasse imbricates during Alpine deformation. Hydrocarbon generation began during the Miocene, and the oil kitchen was located to the south of the Alpine thrust front. Hence, lateral migration over distances of up to 50 km was required to charge the mainly Eocene and Cenomanian non‐ and shallow‐marine sandstone reservoir units. Hydrocarbons are in general trapped in structures related to east‐west trending normal faults, and differences in source rock facies resulted in the development of separate western and eastern oil families. Surprisingly, with the exception of some fields in the eastern part of the study area, associated gas contains varying (and sometimes very high) percentages of primary and secondary microbial methane. The composition of oil in some fields is influenced by both biodegradation and water washing. Post‐Miocene uplift in the Austrian sector of the basin had further effects on biodegradation and the consequent formation of secondary microbial gas, and also resulted in re‐migration. The upper Oligocene to lower Miocene succession (Puchkirchen Group, Hall Formation) provides both source and reservoir rocks for the microbial petroleum system in the Austrian sector of the North Alpine Foreland Basin. TOC contents (<1.0 %) and HI values (<140 mgHC/gTOC) of pelitic source rocks are typically low. Microbial gas was generated shortly after deposition during early diagenesis and was subsequently fixed in gas hydrates. Basin subsidence and high sedimentation rates resulted in decomposition of the hydrates below their stability zone, and reservoirs were filled during the early Miocene. Subsequent mixing of microbial gas with thermogenic gas and condensates is widespread. However, biodegradation has prevented precise determination of the fraction of thermogenic hydrocarbons present in gas samples. Reservoir sandstones were deposited within a deep‐marine channel belt along the axis of the North Alpine Foreland Basin, and reservoir quality depends on the precise position within this belt. In the study area, gas is trapped in compaction anticlines or at channel margin pinch‐outs and additional traps are formed by imbrication structures. Gruber, B., Weggler, B.A., Jaramillo, R., Murrell, K.A., Piotrowski, P.K., Dorman, F.L., 2018. Comprehensive two-dimensional gas chromatography in forensic science: A critical review of recent trends. TrAC Trends in Analytical Chemistry 105, 292-301. two-dimensional gas chromatography (GC?×?GC) has become accepted as one of the most powerful separation techniques in several application areas. In forensic investigations, however, it has not yet been entirely established due to limitations regarding standardized methodology, data interpretation and consistency of results. Nevertheless, GC?×?GC allows for target analysis, compound class analysis and chemical fingerprinting of samples and is therefore increasingly applied in forensic analytics. In this review, recent and significant advances in GC?×?GC for application to forensic studies including human scent, arson investigations, security-relevant substances and environmental forensics are discussed. The discussion includes a brief overview of the latest trends and evolutions with regard to the various forensic applications and data evaluation as well as limitations. This leads to the conclusion that the full potential of the comprehensive data sets can only be achieved by implementing standardized analysis and data processing methods.Guan, Q., Goharzadeh, A., Chai, J.C., Vargas, F.M., Biswal, S.L., Chapman, W.G., Zhang, M., Yap, Y.F., 2018. An integrated model for asphaltene deposition in wellbores/pipelines above bubble pressures. Journal of Petroleum Science and Engineering 169, 353-373. has been recognized as the cholesterol of petroleum for decades due to its precipitation and deposition in oil production, transportation and processing facilities, causing tremendous losses to the oil industry each year. This work presents a numerical model to predict asphaltene deposition in wellbores/pipelines. A Thermodynamic Module is developed to model asphaltene precipitation, based on the sequential stability-testing-and-phase-split-calculation method using Peng-Robinson equation of state with Peneloux volume correction. A Transport Module is developed to model fluid transport, asphaltene particle transport and asphaltene deposition, according to basic conservation laws. Using a thermodynamic properties look-up table, these two modules are linked to each other to account for the effects of a finite deposit layer thickness on the coupled flow fields and deposition process. In this article, verification and validation of the Thermodynamic Module are first carried out. Then, the integrated model is utilized to study asphaltene deposition problems in an actual oilfield where the asphaltene deposit layer profile is reasonably accurately predicted. This case shows that the presented model has great potential as a predicting tool to assist reservoir engineers in assessing asphaltene deposition risks in wellbores/pipelines.Gunde-Cimerman, N., Plemenita?, A., Oren, A., 2018. Strategies of adaptation of microorganisms of the three domains of life to high salt concentrations. FEMS Microbiology Reviews 42, 353-375. environments with salt concentrations up to NaCl saturation are inhabited by a great diversity of microorganisms belonging to the three domains of life. They all must cope with the low water activity of their environment, but different strategies exist to provide osmotic balance of the cells’ cytoplasm with the salinity of the medium. One option used by many halophilic Archaea and a few representatives of the Bacteria is to accumulate salts, mainly KCl and to adapt the entire intracellular machinery to function in the presence of molar concentrations of salts. A more widespread option is the synthesis or accumulation of organic osmotic, so-called compatible solutes. Here, we review the mechanisms of osmotic adaptation in a number of model organisms, including the KCl accumulating Halobacterium salinarum (Archaea) and Salinibacter ruber (Bacteria), Halomonas elongata as a representative of the Bacteria that synthesize organic osmotic solutes, eukaryotic microorganisms including the unicellular green alga Dunaliella salina and the black yeasts Hortaea werneckii and the basidiomycetous Wallemia ichthyophaga, which use glycerol and other compatible solutes. The strategies used by these model organisms and by additional halophilic microorganisms presented are then compared to obtain an integrative picture of the adaptations to life at high salt concentrations in the microbial world.Guo, C., Wang, X., Wang, H., He, S., Liu, H., Zhu, P., 2018. Effect of pore structure on displacement efficiency and oil-cluster morphology by using micro computed tomography (μCT) technique. Fuel 230, 430-439. recovery in mature oil fields, mostly in a high-water-cut stage, requires advanced methods to enhance oil recovery. However, incomplete understanding of the mechanisms of low oil recovery in pore-scale limits the application of proposed methods in industry. Digital core technology and high-resolution micro computed tomography ( μ CT) scanning were deployed to investigate effects of pore structure and permeability scales on oil displacement efficiency and remaining oil-cluster morphology visually and quantitatively. In the study, brine displacing oil experiments were conducted on four naturally water-wet sandstone samples with different permeability scales. A μCT equipment with a resolution of 3.78?μm was used to image the samples at different water flooding stages by injecting brine water with different PV (pore volume): 0 (irreducible water saturation), 1, 5, 15, and 50PV. The complexity of the pore structures of four samples were quantified by fractal dimension analysis from μCT images. The order of pore structure from simple to complex is samples 1, 2, 3, and 4. Then the distributions of cluster pattern of reminding oil were analyzed. Based on the cluster pattern distributions, microscopic remaining oil was classified into five categories by using shape factor and Euler number. Results show that large connected oil clusters can be more easily broken into smaller segments in high permeability samples. Sample 1 has the largest pore connectivity and shows the biggest change of distribution pattern. The clusters are concentrated on one to two distribution patterns. If the permeability gets lower and pore structure becomes complex, all distribution patterns coexist. Also, the lower permeability samples show a smaller displacement efficiency at all displacing stages. A large coordination number improves the displacement efficiency, but the large tortuosity and pore-throat ratio reduce the displacement efficiency. Results of this study can enrich the understandings of the low oil recovery and can inspire innovative methods to further tap those remaining oil.Guo, J., Zhang, L., Liu, S., Li, B., 2018. Effects of hydrophilic groups of nonionic surfactants on the wettability of lignite surface: Molecular dynamics simulation and experimental study. Fuel 231, 449-457. oxygen-containing functional groups make lignite high moisture content, which reduces the utilization efficiency of lignite. The decrease in hydrophilicity of lignite surface can be achieved by treating with surfactant. In the present work, two kinds of nonionic surfactants with different hydrophilic groups, n-dodecyl β-D-maltoside (C12G2) and dodecyl hepta glycol (C12E7), were selected to modify the wettability of lignite surface by molecular dynamics simulation. Because of the drastic differences in compositions and structure of their headgroups, different behaviors were observed. The adsorption results of simulation indicate that polyhydroxy surfactant, C12G2, adsorbs strongly on lignite surface as a comparison to the poly ether surfactant, C12E7. However, the extent of hydrophobicity of modified lignite surface by these surfactants is inconsistent with their adsorption capabilities. Compared to the raw lignite, the hydrophilicity of lignite significantly decreases by adsorption of C12E7, while the C12G2 makes the lignite even more hydrophilicity. The strong polar oxygen-containing functional groups of lignite surface are covered by ethers in C12E7 with weaker polarity, which weakens the interaction between water and lignite. The hydrophilicity of lignite adsorbed C12G2 is strengthened due to the increase in surface polarity by the introduction of polar hydroxyl groups. The results of simulations are in accord with the available experimental data.Gutiérrez Sama, S., Barrère-Mangote, C., Bouyssière, B., Giusti, P., Lobinski, R., 2018. Recent trends in element speciation analysis of crude oils and heavy petroleum fractions. TrAC Trends in Analytical Chemistry 104, 69-76. and heavy crude oils and high-boiling distillation fractions which are increasingly used in petroleum industry contain high concentrations of sulfur and metals. Their behavior in refining processes is critically dependent on the speciation. Recent analytical developments, especially on the level of coupled techniques and high-resolution mass spectrometry, start allowing the speciation of individual metal compounds in crude oil known for its extreme complexity. These developments include: (i) GC stationary phases of high thermal stability and the high-temperature interfaces with ICP-MS and TOF-MS; (ii) high-efficiency microcolumn gel-permeation chromatography with detection by sector-field ICP-MS; (iii) thin layer chromatography coupling with laser ablation ICP-MS detection; and (iv) two-dimensional separation protocols increasing the purity of heteroelement containing fractions. Progress in electrospray and atmospheric-pressure photoionization Fourier Transform MS allows resolutions of above 1,000,000 to be achieved making it possible to identify by accurate mass measurement individual sulfur and metal species directly in crude oils.Haarmann, N., Enders, S., Sadowski, G., 2018. Modeling binary mixtures of n-alkanes and water using PC-SAFT. Fluid Phase Equilibria 470, 203-211. and measuring the mutual solubility in binary n-alkane?+?water mixtures is very challenging due to their low order of magnitude. Consequently, experimental data regarding mutual solubilities of these systems scatter remarkably. In this work, the PC-SAFT equation of state has been applied to model liquid-liquid and vapor-liquid-liquid equilibria of binary n-alkane?+?water mixtures. For this purpose, temperature-dependent binary interaction parameters have been fitted to the n-alkane solubility in the aqueous phase for n-alkanes ranging from n-pentane to n-undecane. Furthermore, these binary interaction parameters have been correlated with the carbon number of the n-alkane in order to predict phase equilibria of binary n-alkane?+?water mixtures for n-alkanes ranging from n-propane to n-pentadecane. Excellent agreement between modeling results and available experimental data has been observed for the liquid-liquid equilibria including the description of the minimum of n-alkane solubility in water as a function of temperature. Even the prediction of the vapor-liquid-liquid equilibria of the respective mixtures showed remarkably good results compared to experimental data.Haghighi, F., Talebpour, Z., Nezhad, A.S., 2018. Towards fully integrated liquid chromatography on a chip: Evolution and evaluation. TrAC Trends in Analytical Chemistry 105, 302-337. of liquid chromatography (LC) is at the leading edge of the research topics and offers a wide range of applications in chemistry, biology, pharmaceutical, clinical diagnosis, and food analysis. The state-of-the-art “lab-on-chip” or “micro-total analysis systems” gathered scientists all over the world to provide systems with the aim of portability, reliability, reduced analysis time and cost of operation and analysis. From the hardware equipment point of view, the LC system is made by the primary compartments of solvent reservoir, pump, injector, column, and detector. In this work, we surveyed the development of LC systems and advances in each of the integrated components (i.e. pumping systems, injectors, separation channels, and detector) and the materials used for their fabrication from the beginning up to now. Finally, we summarize the application of fully integrated LC systems and exemplify about the multidimensional LCs on a chip development.Hakimi, M.H., Al-Matary, A.M., Salad Hersi, O., 2018. Late Jurassic bituminous shales from Marib oilfields in the Sabatayn Basin (NW Yemen): Geochemical and petrological analyses reveal oil-shale resource. Fuel 232, 530-542. this study, bituminous shale samples were collected from Late Jurassic sedimentary section in the Marib oilfields to study their petrologic and organic geochemical properties. The results of this study indicate that the Late Jurassic bituminous shales can be considered as an oil-source rocks in the Sabatayn Basin (NW Yemen). The analyzed Late Jurassic shales have high organic matter (TOC up to 10%) content of kerogen Types I/II. These kerogen types in the analyzed samples are consistent with the high dominance of alginite and amorphous organic matter. Open pyrolysis–gas chromatography results are generally consistent with the Rock-Eval results and further indicate that the analyzed shale samples contain Types I/II and II-S kerogen and generally can produce paraffinic oils with low to high wax content. Type II-S kerogen can produce oil with high sulphur content at low maturity level. The maturity data reflect immature and very early maturity stages of petroleum formation of the Late Jurassic bituminous shales. Therefore, the kerogen types in the Late Jurassic bituminous shales has not been altered by thermal maturity for oil generation, thus, artificial heating is required of kerogen cracking generate significant oil.Hall, J.L.O., Newton, R.J., Witts, J.D., Francis, J.E., Hunter, S.J., Jamieson, R.A., Harper, E.M., Crame, J.A., Haywood, A.M., 2018. High benthic methane flux in low sulfate oceans: Evidence from carbon isotopes in Late Cretaceous Antarctic bivalves. Earth and Planetary Science Letters 497, 113-122. shell material of marine benthic bivalves provides a sensitive archive of water chemistry immediately above the sediment–water interface, which in turn is affected by sedimentary geochemistry and redox reactions. Sulfate has a major controlling effect on sedimentary carbon cycling, particularly the processes of methane production and oxidation, with lower concentrations of sulfate likely resulting in an increase in sedimentary methane production. Whilst it is accepted that ocean sulfate varied markedly across the Phanerozoic, evidence of changes in methane production in sediments has so far been lacking. There is potential for the oxidation products of sedimentary methane to be preserved and detected in marine fossils. Here we present the results of high resolution carbonate isotope records from two taxa of well-preserved shallow-infaunal bivalve (Lahillia and Cucullaea) collected from the marine shelf succession across the Cretaceous–Paleogene (K–Pg) boundary in Seymour Island, Antarctica. The succession has pre-existing subtle indications of more abundant methane, and the time period is characterized by much lower marine sulfate concentrations than modern.These shell carbonate–carbon isotope records vary widely: at one extreme, shells have typical average values and small ranges compatible with a contemporaneous marine dissolved inorganic carbon (DIC) source and modern-style sedimentary carbon cycling. At the other, the shells have large-amplitude annual cycles of carbon isotopic variability of up to 23.8‰ within a single year of growth and shell carbonate δ13C compositions as negative as ?34‰. Shells with these increased ranges and unusually negative values are found at discrete intervals and across both bivalve taxa. The contribution of methane required to explain the most negative carbonate–carbon isotopic values in the bivalve shells is extremely high (between 30 to 85% of bottom-water DIC based on mass balance calculations). Records of organic-carbon isotopes from the same succession remained between ?26.1 and ?21.7‰ throughout, suggesting that methane influence was restricted to bottom-waters. A lack of authigenic carbonate in the section indicates that methane oxidation progressed aerobically and may have provided a significant driver for transient bottom water de-oxygenation.Where methane addition is indicated, the seasonal sensitivity precludes control by methane hydrates. We argue that these data represent the increased importance and sensitivity of methanogenesis in the sediments, enabled by lower ocean sulfate concentrations during the Late Cretaceous. The tendency towards a more dynamic role for marine methane production and oxidation is likely to apply to other times of low marine sulfate in Earth's history.Han, T., Fan, H., Wen, H., 2018. Dwindling vanadium in seawater during the early Cambrian, South China. Chemical Geology 492, 20-29. vanadium (V), an essentially redox-sensitive metal in seawater, has had a significant impact on the understanding of the evolution of the atmosphere-ocean system throughout the history of the Earth. In fact, the geochemical cycle of V in early Cambrian seawater may have had an influence on the Chengjiang Biota in South China; however, it has not yet been well established. Given the authigenic vanadium accumulation is sensitive to the redox conditions of seawater, here, to constrain the geochemical cycle of V in seawater during the early Cambrian, the Mo, U and total organic carbon (TOC) distributions with high-resolution samples from both the outer shelf and slope facies (e.g., the Duoding and Longbizui sections), are applied to evaluate the redox conditions of ambient seawater. The Mo-U relationships indicate that the redox conditions of the mid-depth seawater evolved in a systematic way in South China, transitioning from an Fe-Mn reduction zone to anoxic/intermittently euxinic states and then to oxic conditions during the early Cambrian. As a consequence, the authigenic V enrichment, constrained by the marine redox conditions, was mainly controlled by the Fe-Mn particulate shuttle and the reduction and adsorption of organic matter in anoxic/euxinic conditions. However, the decoupling among V, Mo, U and TOC under anoxic/euxinic conditions suggests a dwindling vanadium concentration in the early Cambrian seawater of South China. The scavenging efficiency of V from seawater is much higher than those of Mo and U under anoxic/euxinic conditions. Ultimately, these trace elements (e.g., Mo, U, and especially V) in seawater could effectively be regulated and adjusted to a reasonable level under the widespread anoxic/euxinic conditions. The drawdown of trace elements in seawater might provide an early-stage preparation of the marine environment for the subsequent Chengjiang Biota.Hanna, A.J.M., Shanahan, T.M., Allison, M.A., Bianchi, T.S., Schreiner, K.M., 2018. A multi-proxy investigation of late-Holocene temperature change and climate-driven fluctuations in sediment sourcing: Simpson Lagoon, Alaska. The Holocene 28, 984-997. significant and ongoing environmental changes in Arctic regions demonstrate the need for quantitative, high-resolution records of pre-industrial climate change in this climatically sensitive region; such records are fundamental for understanding recent anthropogenic changes in the context of natural variability. Sediment contained within Arctic coastal environments proximal to large fluvial systems has the ability to record paleoclimate variability on subdecadal to decadal scale resolution, on par with many other terrestrial climate archives (i.e. lake sediments, ice cores). Here, we utilize one such sediment archive from Simpson Lagoon, Alaska, located adjacent to the Colville River Delta to reconstruct temperature variability and fluctuations in sediment sourcing over the past 1700 years. Quantitative reconstructions of summer air temperature are obtained using the branched glycerol dialkyl glycerol tetraether (brGDGT)-derived methylation index of branched tetraethers (MBT’)/cyclization ratio of branched tetraether (CBT) paleothermometer and reveal temperature departures correlative with noted climate events (i.e. ‘Little Ice Age’, ‘Medieval Climate Anomaly’). In addition, temporal variability in sediment sourcing to the lagoon, determined using a multi-proxy approach (i.e. granulometry, elemental analysis, clay mineralogy), broadly corresponds with temperature fluctuations, indicating relative increases in fluvial sediment discharge during colder intervals and decreased river discharge/increased coastal erosion during warmer periods. The Simpson Lagoon record presented in this study is the first temperature reconstruction, to our knowledge, developed from coastal marine sediments in the Alaskan Beaufort Sea.Hao, H., Zhao, J., Liu, H., Zhong, G., Ma, W., Xue, P., Lu, W., Dieyan, C., 2018. Prediction of oil and gas reservoir traps by aromatic hydrocarbons from seabed sediments in Chaoshan depression,South China Sea. Acta Petrolei Sinica 39, 528-540. this study, an advanced geochemical exploration technology is used to predict possible oil and gas traps by detecting the content distribution of aromatic hydrocarbons in seabed sediments. Using new high-polymer adsorption materials, the trace benzene, toluene, ethylbenzene and xylene(BTEX), naphthalene, phenanthrene, anthracene(PAHs) and other aromatic components in marine surficial sediments are extracted rapidly and efficiently. On this basis, thermal desorption and gas chromatography mass spectrometry(GC-MS) are further applied to complete the qualitative and quantitative analysis of trace BTEX and PAHs in sediments. According to abnormal range of BTEX and PAHs concentrations, oil and gas traps are predicted. Based on the validation results of LW3-1 oil and gas field in Liwan area, Baiyun Depression of the deep waters on the northern slope of South China Sea as well as the two-dimensional seismic exploration results in the new Mesozoic hydrocarbon exploration areas(Chaoshan Depression), Dongsha seawaters of South China Sea, the deep waters with the depth of 1000-1500 m on the northern slope zone and central uplift belt of Chaoshan Depression are proposed to be the frontier exploration areas for Mesozoic oil and gas reservoirs. It provides an important reference for shrinking exploration target areas and reducing exploration cost.Hao, Y., Wang, W., Yuan, B., Su, Y., An, J., Shu, H., 2018. Shale gas simulation considering natural fractures, gas desorption, and slippage flow effects using conventional modified model. Journal of Petroleum Exploration and Production Technology 8, 607-615. paper presents the theory and application to modify the conventional simulator to describe the effects of gas adsorption and gas slippage flow in shale gas. Because of the local desorption of gas and the assumptions of gas desorption instantaneously with the decrease in pore pressure, we define one fictitious immobile “pseudo” oil with dissolved gas. The dissolved gas–oil ratio is calculated from the Langmuir adsorption isotherm constants and shale gas properties. Additional modifications required in the input data are the porosity and relative permeability curves to account for the existence of “pseudo” oil. The input rock table considers the changes of rock permeability versus pressure to describe the gas slippage flow effects. In addition, dual-porosity dual-permeability models coupled with local grid refinement method are used to distinguish the impacts of natural fractures and hydraulic fractures on shale gas production with the comparison of vertical well, fractured vertical well, horizontal well, and multistage fractured horizontal well production. This proposed simulation approach shows enough accuracy and outstanding time efficiency. Results show that ignoring gas desorption and slippage flow effects would bring significant error in shale gas simulation The existence of natural fractures also imposes great effects on the productivity of shale gas.Hardy, K., 2018. Plant use in the Lower and Middle Palaeolithic: Food, medicine, and raw materials. Quaternary Science Reviews 191, 393-405. is little surviving evidence for plant use in the Lower and Middle Palaeolithic periods yet the evidence there is, clearly indicates the importance of plants in the diet, as medicines and as raw materials. Here, the current evidence for plants is summarised, and the way this can be used to enrich perceptions of the Lower and Middle Palaeolithic are explored. The evidence for plant food fits well with basic nutritional requirements while the presence of medicinal plants correlates with plant-based self-medication by animals. Many plant-based technologies are likely to have developed early in the Palaeolithic. Though investigating this is challenging due to a lack of evidence, the extensive evidence for use of plant materials as tools by chimpanzees provides a broad backdrop. The ecological knowledge carried by all hominins would have provided a safety net when moving into new regions, while varying levels of neophobia would have enabled adaptation to new environments as hominin populations moved and climates changed. Recent plant use among traditional societies in high latitudes shows that even in locations with reduced biodiversity, plant resources can fulfil essential dietary requirements.Harman, C.E., Pavlov, A.A., Babikov, D., Kasting, J.F., 2018. Chain formation as a mechanism for mass-independent fractionation of sulfur isotopes in the Archean atmosphere. Earth and Planetary Science Letters 496, 238-247. anomalous abundances of sulfur isotopes in ancient sediments provide the strongest evidence for an anoxic atmosphere prior to ～2.45 Ga, but the mechanism for producing this ‘mass-independent’ fractionation pattern remains in question. The prevailing hypothesis has been that it is created by differences in the UV photolysis rates of different SO2 isotopologues. We investigate here a recently proposed additional source of fractionation during gas-phase formation of elemental sulfur (S4 and S8). Because two minor S isotopes rarely occur in the same chain, the longer S4 and S8 chains should be strongly, and roughly equally, depleted in all minor isotopes. This gives rise to negative Δ33S values and positive Δ 36 S values in elemental sulfur—just the opposite of (and much larger than) what is predicted from SO2 photolysis itself. Back-reactions during chain formation, specifically photolysis of S2 and S3, pass sulfur having the opposite fractionation back to atomic S, and thence to other sulfur species, causing H2S, SO2, sulfate, and short-chain elemental sulfur to have positive Δ33S and negative Δ36S. Positive Δ33S values in elemental sulfur produced in laboratory SO2 photolysis experiments could be caused by the initial fractionation during photolysis, combined with rapid condensation of short-chain sulfur species on the walls of the reaction chamber, along with a scarcity of back-reactions. The simulated fractionations produced by the chain formation mechanism do not directly match fractionations from the rock record. The mismatch might be explained if the isotopic signals leaving the atmosphere were significantly modulated by life, by uncertainties in the rates of reactions of both major and minor isotopic sulfur species, or by the relatively large potential range of atmospheric parameters. Further work is needed to better constrain these uncertainties, but this novel mechanism suggests new avenues to explore in our search for a explanation for the S-MIF record.Harmsen, J., Rietra, R.P.J.J., 2018. 25 years monitoring of PAHs and petroleum hydrocarbons biodegradation in soil. Chemosphere 207, 229-238. of polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPH) in sediment and soil has been monitored on seven experimental fields during periods up to 25 years. With this unique dataset, we investigated long-term very slow biodegradation under field conditions. . The data show that three biodegradation rates can be distinguished for PAHs: 1) rapid degradation during the first year, 2) slow degradation during the following 6 years and 3), subject of this paper, a very slow degradation after 7 years until at least 25 years. Beside 2-, 3- and 4-ring PAHs, also 5- and 6-ring PAHs (aromatic rings) were degraded, all at the same rate during very slow degradation. In the period of very slow degradation, 6% yr?1 of the PAHs present were removed in five fields and 2% yr?1 in two other fields, while in the same period no very slow degradation of TPH could be observed. The remaining petroleum hydrocarbons were high boiling and non-toxic. Using the calculated degradation rates and the independently measured bioavailability of the PAHs (Tenax-method), the PAHs degradation curves of all seven monitored fields could be modelled. Applying the model and data obtained with the Tenax-method for fresh contaminated material, results of long-term biodegradation can be predicted, which can support the use of bioremediation in order to obtain a legally acceptable residual concentration.Hashemi, B., Zohrabi, P., Shamsipur, M., 2018. Recent developments and applications of different sorbents for SPE and SPME from biological samples. Talanta 187, 337-347. phase extraction (SPE) and solid phase microextraction (SPME) are among the most significant sample clean-up and pretreatment techniques, which have attracted a considerable interest in the pre-concentration and determination of a wide variety of analytes in biological, pharmaceutical, environmental, industrial and food samples. The purpose of this review article is to focus on the latest advancements and applications of SPE and SPME methods based on new nanomaterial adsorbents for separation, concentration and determination of different analytes in biological media. To this end, some sorbents such as metal organic frameworks, molecularly/ion-imprinted polymers, carbon nanotubes, magnetic nanoparticles, graphene and graphene oxide, and metallic nanoparticles are discussed here.Hausmann, B., Pelikan, C., Herbold, C.W., K?stlbacher, S., Albertsen, M., Eichorst, S.A., Glavina del Rio, T., Huemer, M., Nielsen, P.H., Rattei, T., Stingl, U., Tringe, S.G., Trojan, D., Wentrup, C., Woebken, D., Pester, M., Loy, A., 2018. Peatland Acidobacteria with a dissimilatory sulfur metabolism. The ISME Journal 12, 1729-1742. microorganisms impact organic matter decomposition in wetlands and consequently greenhouse gas emissions from these globally relevant environments. However, their identities and physiological properties are largely unknown. By applying a functional metagenomics approach to an acidic peatland, we recovered draft genomes of seven novel Acidobacteria species with the potential for dissimilatory sulfite (dsrAB, dsrC, dsrD, dsrN, dsrT, dsrMKJOP) or sulfate respiration (sat, aprBA, qmoABC plus dsr genes). Surprisingly, the genomes also encoded DsrL, which so far was only found in sulfur-oxidizing microorganisms. Metatranscriptome analysis demonstrated expression of acidobacterial sulfur-metabolism genes in native peat soil and their upregulation in diverse anoxic microcosms. This indicated an active sulfate respiration pathway, which, however, might also operate in reverse for dissimilatory sulfur oxidation or disproportionation as proposed for the sulfur-oxidizing Desulfurivibrio alkaliphilus. Acidobacteria that only harbored genes for sulfite reduction additionally encoded enzymes that liberate sulfite from organosulfonates, which suggested organic sulfur compounds as complementary energy sources. Further metabolic potentials included polysaccharide hydrolysis and sugar utilization, aerobic respiration, several fermentative capabilities, and hydrogen oxidation. Our findings extend both, the known physiological and genetic properties of Acidobacteria and the known taxonomic diversity of microorganisms with a DsrAB-based sulfur metabolism, and highlight new fundamental niches for facultative anaerobic Acidobacteria in wetlands based on exploitation of inorganic and organic sulfur molecules for energy conservation.Hawes, I., Jungblut, A.D., Matys, E.D., Summons, R.E., 2018. The “Dirty Ice” of the McMurdo Ice Shelf: Analogues for biological oases during the Cryogenian. Geobiology 16, 369-377. Cryogenian (~717–636 Ma) is characterized by widespread glaciation and dramatic fluctuations in biogeochemical cycling during the Sturtian and Marinoan glaciations. The Snowball Earth hypothesis posits that during this period, ice‐covered oceans of more or less global extent shut down or greatly diminished photosynthesis in the marine realm. However, rather than suffering a catastrophic loss of biodiversity, fossil evidence suggests that major eukaryotic lineages survived and, indeed, the end of the Cryogenian marks the onset of a rapid diversification of eukaryotic life. Persistence of diverse life forms through glaciations is thought to have occurred in supraglacial refugia although the exact nature and full extent of such habitats remain uncertain. We present further evidence for the diversity and characteristics of supraglacial ecosystems on the McMurdo Ice Shelf in Antarctica and suggest that refugia analogous to “dirty ice,” that is debris‐covered ice shelf ecosystems, potentially provided nutrient‐rich and long‐lasting biological Cryogenian oases. We also discuss how features of the McMurdo Ice Shelf indicate that mechanisms exist whereby material can be exchanged between the shallow sea floor and the surfaces of ice shelves along continental margins, providing vectors whereby ice shelf ecosystems can nourish underlying seafloor communities and vice versa. Hay, A., Samson, C., Ellery, A., 2018. Robotic magnetic mapping with the Kapvik planetary micro-rover. International Journal of Astrobiology 17, 218-227. data gathering by micro-rovers is gaining momentum both for future planetary exploration missions and for terrestrial applications in extreme environments. This paper presents research into the integration of a planetary micro-rover with a potassium total-field magnetometer. The 40 kg Kapvik micro-rover is an ideal platform due to an aluminium construction and a rocker-bogie mobility system, which provides good manoeuvrability and terrainability. A light-weight GSMP 35U (uninhabited aerial vehicle) magnetometer, comprised of a 0.65 kg sensor and 0.63 kg electronics module, was mounted to the chassis via a custom 1.21 m composite boom. The boom dimensions were optimized to be an effective compromise between noise mitigation and mechanical practicality. An analysis using the fourth difference method was performed estimating the magnetic noise envelope at ±0.03 nT at 10 Hz sampling frequency from the integrated systems during robotic operations. A robotic magnetic survey captured the total magnetic intensity along three parallel 40 m long lines and a perpendicular 15 m long tie line over the course of 3.75 h. The total magnetic intensity data were corrected for diurnal variations, levelled by linear interpolation of tie-line intersection points, corrected for a regional gradient, and then interpolated using Delaunay triangulation to lead a residual magnetic intensity map. This map exhibited an anomalous linear feature corresponding to a magnetic dipole 650 nT in amplitude. This feature coincides with a storm sewer buried approximately 2 m in the subsurface. This work provides benchmark methodologies and data to guide future integration of magnetometers on board planetary micro-rovers.He, L., Prodhan, M.A.I., Yuan, F., Yin, X., Lorkiewicz, P.K., Wei, X., Feng, W., McClain, C., Zhang, X., 2018. Simultaneous quantification of straight-chain and branched-chain short chain fatty acids by gas chromatography mass spectrometry. Journal of Chromatography B 1092, 359-367. research in areas such as metabolic disorders, neuromodulatory, and immunomodulatory conditions involves lipid metabolism and demands a reliable and inexpensive method for quantification of short chain fatty acids (SCFAs). We report a GC–MS method for analysis of all straight-chain and branched-chain SCFAs using pentafluorobenzyl bromide (PFBBr) as derivatization reagent. We optimized the derivatization and GC–MS conditions using a mixture containing all eight SCFA standards, i.e., five straight-chain and three branched-chain SCFAs. The optimal derivatization conditions were derivatization time 90?min, temperature 60?°C, pH?7, and (CH3)2CO:H2O ratio 2:1 (v:v). Comparing the performance of different GC column configurations, a 30?m DB-225ms hyphenated with a 30?m DB-5ms column in tandem showed the best separation of SCFAs. Using the optimized experiment conditions, we simultaneously detected all SCFAs with much improved detection limit, 0.244–0.977?μM. We further applied the developed method to measure the SCFAs in mouse feces and all SCFAs were successfully quantified. The recovery rates of the eight SCFAs ranged from 55.7% to 97.9%.He, T., Lu, S., Li, W., Tan, Z., Zhang, X., 2018. Effect of salinity on source rock formation and its control on the oil content in shales in the Hetaoyuan Formation from the Biyang Depression, Nanxiang Basin, Central China. Energy & Fuels 32, 6698-6707. total of 75 shale samples from the Biyang Depression were analyzed with Rock-Eval, total organic carbon (TOC), organic maceral, and gas chromatography–mass spectrometry (GC–MS) techniques to reveal the effect of salinity on source rock formation and its control on the oil content. On the basis of the diversities in salinity and redox conditions reflected by the gammacerane/αβ C30 hopane (G/H) ratio, the pristine/phytane (Pr/Ph) ratio, and the extended tricyclic terpane ratio [ETR = (C28 + C29) tricyclic terpane/Ts)], three types (T1, T2, and T3) of shales were identified, which deposited in the brackish condition (G/H ratio < 0.3), the semi-saline condition (G/H ratio = 0.3–0.6), and the saline condition (G/H ratio > 0.6), respectively. The comparisons among T1, T2, and T3 shales revealed that the salinity had a significant effect on the paleoproductivity of the lacustrine system. Most algae thrive in semi-saline conditions (T2) but are restrained in saline conditions (T3), so that moderate salinity conditions (G/H ratio = 0.3–0.6) are most conducive to the accumulation of algae organic matter (AOM). Although they have similar thermal maturity (0.6–1.1% vitrinite reflectance) and kerogen type (type II), the T1, T2, and T3 shales were developed in different reducing environments indicated by the Pr/Ph ratio and contained variable abundance of organic matter, resulting in remarkable differences in the preservation condition of AOM and the shale oil content within the T1, T2, and T3 shales. The classification and evaluation criteria of the shale oil resource were performed according to three categories based on the oil content (S1) and TOC values. It was revealed that the T1, T2, and T3 source rocks were mainly distributed among these areas of the potential, enriched, and ineffective shale oil resources, respectively, suggesting that shales developed in semi-saline environments deserve to be the most desirable target of shale oil exploration and development at present. Thus, this work may help related industry practitioners acquire valuable information from lacustrine shale systems.Heidke, I., Scholz, D., Hoffmann, T., 2018. Quantification of lignin oxidation products as vegetation biomarkers in speleothems and cave drip water Biogeosciences Discussions 2018, 1-23. we present a sensitive method to analyse lignin oxidation products (LOPs) in speleothems and cave drip water to provide a new tool for paleo vegetation reconstruction. Speleothems are valuable climate archives. However, compared to other terrestrial climate archives, such as lake sediments, speleothems contain very little organic matter. Therefore, very few studies on organic biomarkers in speleothems are available. Our new sensitive method allows to use LOPs as vegetation biomarkers in speleothems.Our method consists of acid digestion of the speleothem sample followed by solid phase extraction (SPE) of the organic matter. The extracted polymeric lignin is degraded in a microwave assisted alkaline CuO oxidation step to yield monomeric LOPs. The LOPs are extracted via SPE and finally analysed via ultrahigh-performance liquid chromatography (UHPLC) coupled to electrospray ionisation (ESI) and high-resolution orbitrap mass spectrometry (HRMS). The method was applied to stalagmite samples with a sample size of 3–5?g and cave drip water samples with a sample size of 100–200?mL from the Herbstlabyrinth-Advent-Cave in Germany. In addition, fresh plant samples, soil water and powdered lignin samples were analysed for comparison. The concentration of the sum of eight LOPs (Σ8) was in the range of 20–84?ng?g?1 for the stalagmite samples and 230–440?ng?L?1 for the cave drip water samples. The limits of quantification for the individual LOPs ranged from 0.3–8.2?ng per sample.Our method represents a new and powerful analytical tool for paleo vegetation studies and has great potential to identify the pathways of lignin incorporation into speleothems.Heindel, K., Foster, W.J., Richoz, S., Birgel, D., Roden, V.J., Baud, A., Brandner, R., Krystyn, L., Mohtat, T., Ko?un, E., Twitchett, R.J., Reitner, J., Peckmann, J., 2018. The formation of microbial-metazoan bioherms and biostromes following the latest Permian mass extinction. Gondwana Research 61, 187-202. the latest Permian mass extinction event, microbial mats filled the ecological niche previously occupied by metazoan reefs, resulting in widespread microbialites. This study focuses on the lipid biomarker (molecular fossil) and invertebrate fossil records from Neotethyan platform margin sections to understand microbial-metazoan bioherm formation. Here, we find that early Griesbachian thrombolitic and stromatolitic microbialites from ?ürük Dag (Turkey) and Kuh e Surmeh (Iran) contain abundant lipid biomarkers, representing input from cyanobacteria, anoxygenic phototrophic bacteria, sulfate-reducing bacteria, and halophilic archaea. The biomarker inventory suggests that the microbialites were constructed by cyanobacteria-dominated microbial mats. Biomarkers of halophilic archaea are interpreted to reflect input from the water column, suggesting that the Neotethys experienced at least episodically hypersaline conditions. We also demonstrate that bacteria, possible keratose sponges (up to 50% of the carbonate is represented by the possible sponges), and microconchids lived synergistically to form microbial-metazoan bioherms in the immediate aftermath of the extinction along the western margin of the Neotethys. Abundant fossils of oxygen-dependent invertebrates (i.e. microconchids, bivalves, gastropods, brachiopods, and ostracods) and foraminifers were also found within these bioherms. The presence of invertebrates in conjunction with abundant molecular fossils of cyanobacteria indicates an oxygenated water column. Even though the presence of the biomarker isorenieratane in microbialites may considered as evidence for euxinic conditions in the water column, its absence in the background sediments rather points to a source organism belonging to the mat community. The new finding of bioherms built in part by metazoans suggests that reef ecosystems underwent a major turnover across the extinction event, and shortens the ‘metazoan reef gap’ to just the uppermost Changhsingian. During the Early Triassic, therefore, reefal ecosystems were able to recover in oxygenated settings since the earliest Griesbachian, albeit in an impoverished state.Heninger, M., Mestdagh, H., Louarn, E., Mauclaire, G., Boissel, P., Leprovost, J., Bauchard, E., Thomas, S., Lemaire, J., 2018. Gas analysis by electron ionization combined with chemical ionization in a compact FTICR mass spectrometer. Analytical Chemistry 90, 7517-7525. this Article, a compact Fourier transform ion cyclotron resonance (FTICR) mass spectrometer based on a permanent magnet is presented. This instrument has been developed for real-time analysis of gas emissions. The instrument is well-suited to industrial applications or analysis of toxic and complex samples where the concentrations can vary rapidly on a wide range. The novelty of this instrument is the ability to use either electron ionization (EI) or chemical ionization (CI) individually or both of them alternatively. Also in CI mode, different precursor ions can be used alternatively. Volatile organic compounds (VOCs) from the ppb level to very high concentrations (% level) can be detected by CI or EI. The magnet is composed of three Halbach arrays, and the nominal field achieved is 1.5 T. The ICR cell is a 3 cm side length cubic cell. The mass range is 12–200 u with a broad band detection. The mass accuracy of 0.005 u and the resolving power allow the separation of isobaric ions such as C3H8+ and CO2+. Gas introduction via controlled gas pulses, electron ionization, ion–molecule reactions, ion selection, and detection are all performed in the ICR cell. The potential of the instrument will be illustrated by an analysis of a gas mixture containing trace components at ppm level (VOCs) and components in the 0.5–100% range (N2, alkanes, and CO2).Hermon, L., Denonfoux, J., Hellal, J., Joulian, C., Ferreira, S., Vuilleumier, S., Imfeld, G., 2018. Dichloromethane biodegradation in multi-contaminated groundwater: Insights from biomolecular and compound-specific isotope analyses. Water Research 142, 217-226. (DCM) is a widespread and toxic industrial solvent which often co-occurs with chlorinated ethenes at polluted sites. Biodegradation of DCM occurs under both oxic and anoxic conditions in soils and aquifers. Here we investigated in situ and ex situ biodegradation of DCM in groundwater sampled from the industrial site of Themeroil (France), where DCM occurs as a major co-contaminant of chloroethenes. Carbon isotopic fractionation (εC) for DCM ranging from??46 to??22‰ were obtained under oxic or denitrifying conditions, in mineral medium or contaminated groundwater, and for laboratory cultures of Hyphomicrobium sp. strain GJ21 and two new DCM-degrading strains isolated from the contaminated groundwater. The extent of DCM biodegradation (B%) in the aquifer, as evaluated by compound-specific isotope analysis (δ13C), ranged from 1% to 85% applying DCM-specific εC derived from reference strains and those determined in this study. Laboratory groundwater microcosms under oxic conditions showed DCM biodegradation rates of up to 0.1?mM·day?1, with concomitant chloride release. Dehalogenase genes dcmA and dhlA involved in DCM biodegradation ranged from below 4?×?102 (boundary) to 1?×?107 (source zone) copies L?1 across the contamination plume. High-throughput sequencing on the 16S rrnA gene in groundwater samples showed that both contaminant level and terminal electron acceptor processes (TEAPs) influenced the distribution of genus-level taxa associated with DCM biodegradation. Taken together, our results demonstrate the potential of DCM biodegradation in multi-contaminated groundwater. This integrative approach may be applied to contaminated aquifers in the future, in order to identify microbial taxa and pathways associated with DCM biodegradation in relation to redox conditions and co-contamination levels.Hesketh, E.L., Saunders, K., Fisher, C., Potze, J., Stanley, J., Lomonossoff, G.P., Ranson, N.A., 2018. The 3.3?? structure of a plant geminivirus using cryo-EM. Nature Communications 9, Article 2369. are major plant pathogens that threaten food security globally. They have a unique architecture built from two incomplete icosahedral particles, fused to form a geminate capsid. However, despite their importance to agricultural economies and fundamental biological interest, the details of how this is realized in 3D remain unknown. Here we report the structure of Ageratum yellow vein virus at 3.3?? resolution, using single-particle cryo-electron microscopy, together with an atomic model that shows that the N-terminus of the single capsid protein (CP) adopts three different conformations essential for building the interface between geminate halves. Our map also contains density for ~7 bases of single-stranded DNA bound to each CP, and we show that the interactions between the genome and CPs are different at the interface than in the rest of the capsid. With additional mutagenesis data, this suggests a central role for DNA binding-induced conformational change in directing the assembly of geminate capsids.Hickok, K.A., Nguyen, T.B., Lang, S.Q., 2018. Assessment of apolar lipids in subseafloor rocks and potential contaminants from the Atlantis Massif (IODP Expedition 357). Organic Geochemistry 122, 68-77. Ocean Discovery Program Expedition 357 drilled 17 boreholes across the Atlantis Massif with the goals of investigating carbon cycling and the presence of life in a zone of active serpentinization. The expedition recovered multiple lithologies including gabbros, basalts, carbonate sands, and serpentinites. A subset of contrasting lithologies were analyzed for apolar lipid content to determine if non-volatile organic molecules can be detected in the oceanic subsurface. The definitive detection and identification of abiotic and biological lipids in the subsurface of an actively serpentinizing system would be a significant step towards understanding a variety of scientific processes, including the evolution of pre-biotic chemistry, microbial habitability, and the global carbon cycle. Given the high potential for contamination during drilling, a suite of materials used in sample collection and processing were also analyzed to characterize their signatures. An n-alkane series ranging from C18 to C30 with δ13C isotopic values of ?30.9‰ to ?28.8‰ was present in lithologically diverse samples. Multiple lines of evidence point to the rock saw used to remove core exteriors during sample processing as the source of these compounds. Many of the other sample-handling procedures designed to reduce surface contamination were determined to be effective and could be implemented in future projects. This result highlights the value of careful prevention and characterization of contamination to allow for more accurate interpretations of complex and dynamic subsurface processes, and the importance that future reports of these compounds occurs in conjunction with thorough contamination assessments.Higashi, K., Kawai, Y., Baba, T., Kurokawa, K., Oshima, T., 2018. Essential cellular modules for the proliferation of the primitive cell. Geoscience Frontiers 9, 1155-1161. appeared early in the evolution of cellular life on planet Earth, and therefore the universally essential genes or biological pathways found across bacterial domains may represent fundamental genetic or cellular systems used in early life. The essential genes and the minimal gene set required to support bacterial life have recently been experimentally and computationally identified. It is, however, still hard to estimate the ancient genes present in primitive cells compared to the essential genes in contemporary bacteria, because we do not know how ancestral primitive cells lived and proliferated, and therefore cannot directly evaluate the essentiality of the genes in ancestral primitive cells. The cell wall is normally essential for bacterial proliferation and cellular division of walled bacterial cells is normally highly controlled by the essential FtsZ cell division machinery. But, bacteria are capable of reverting to their cell wall deficient ancestral form, called the “L-form”. Unlike “normal” cells, L-forms divide by a simple physical mechanism based on the effects of membrane dynamics, suggesting a mode of primitive proliferation before the appearance of the cell wall. In this review, we summarize the experimental and computational investigations of minimal gene sets and discuss the minimal cellular modules required to support the proliferation of primitive cells, based on L-form proliferation.Hoffmann, F., Jaeger, C., Bhattacharya, A., Schmitt, C.A., Lisec, J., 2018. Nontargeted identification of tracer incorporation in high-resolution mass spectrometry. Analytical Chemistry 90, 7253-7260.“Fluxomics” refers to the systematic analysis of metabolic fluxes in a biological system and may uncover novel dynamic properties of metabolism that remain undetected in conventional metabolomic approaches. In labeling experiments, tracer molecules are used to track changes in the isotopologue distribution of metabolites, which allows one to estimate fluxes in the metabolic network. Because unidentified compounds cannot be mapped on pathways, they are often neglected in labeling experiments. However, using recent developments in de novo annotation may allow to harvest the information present in these compounds if they can be identified. Here, we present a novel tool (HiResTEC) to detect tracer incorporation in high-resolution mass spectrometry data sets. The software automatically extracts a comprehensive, nonredundant list of all compounds showing more than 1% tracer incorporation in a nontargeted fashion. We explain and show in an example data set how mass precision and other filter heuristics, calculated on the raw data, can efficiently be used to reduce redundancy and noninformative signals by 95%. Ultimately, this allows to quickly investigate any labeling experiment for a complete set of labeled compounds (here 149) with acceptable false positive rates. We further re-evaluate a published data set from liquid chromatography-electrospray ionization (LC-ESI) to demonstrate broad applicability of our tool and emphasize importance of quality control (QC) tests. HiResTEC is provided as a package in the open source software framework R and is freely available on CRAN.Holman, A.I., Grice, K., 2018. δ13C of aromatic compounds in sediments, oils and atmospheric emissions: A review. Organic Geochemistry 123, 27-37. review discusses major applications of stable carbon isotopic measurements of aromatic compounds, along with some specific technical aspects including purification of aromatic fractions for baseline separation. δ13C measurements of organic matter (OM) in sediments and oils are routine in all fields of organic geochemistry, but they are predominantly done on saturated compounds. Aromatic compounds are important contributors to sedimentary organic matter, and provide indication of diagenetic processes, OM source, and thermal maturity. Studies have found evidence for a small 13C-enrichment during diagenetic aromatisation of approximately 1–2‰, but the formation of polycyclic aromatic hydrocarbons (PAHs) from combustion and hydrothermal processes seems to produce no effect. Likewise, maturation and biodegradation also produce only small isotopic effects. An early application of δ13C of aromatic compounds was in the classification of oil families by source. Bulk measurements have had some success in differentiating marine and terrigenous oils, but were not accurate in all settings. Compound-specific analyses measure certain aromatics with strong links to source, therefore allowing more accurate source identification. δ13C measurements of individual aromatic compounds also allow identification of higher plant input in ancient sediments, even after severe diagenetic alteration or combustion to PAHs. Perylene, a PAH with a historically contentious origin, was assigned a source from wood-degrading fungi on the basis of its isotopic composition. Stable carbon isotopic measurements are also important in the analysis of organic matter from Chlorobiaceae, which is an important indicator of photic zone euxinic conditions in ancient sediments. A large range of aromatic products are formed from the carotenoid pigments of Chlorobiaceae, with an enriched carbon isotopic composition characteristic of the reverse tricarboxylic acid photosynthetic pathway employed by this family of organisms. In future, site-specific isotope analysis using techniques such as nuclear magnetic resonance spectrometry and high-resolution isotope ratio mass spectrometry may reveal more information about isotopic effects associated with aromatisation processes and maturation.Hooper, D., 2018. Life versus dark energy: How an advanced civilization could resist the accelerating expansion of the Universe. arXiv:1806.05203 [astro-ph.CO]. presence of dark energy in our universe is causing space to expand at an accelerating rate. As a result, over the next approximately 100 billion years, all stars residing beyond the Local Group will fall beyond the cosmic horizon and become not only unobservable, but entirely inaccessible, thus limiting how much energy could one day be extracted from them. Here, we consider the likely response of a highly advanced civilization to this situation. In particular, we argue that in order to maximize its access to useable energy, a sufficiently advanced civilization would chose to expand rapidly outward, build Dyson Spheres or similar structures around encountered stars, and use the energy that is harnessed to accelerate those stars away from the approaching horizon and toward the center of the civilization. We find that such efforts will be most effective for stars with masses in the range of M～(0.2?1)M⊙, and could lead to the harvesting of stars within a region extending out to several tens of Mpc in radius, potentially increasing the total amount of energy that is available to a future civilization by a factor of several thousand. We also discuss the observable signatures of a civilization elsewhere in the universe that is currently in this state of stellar harvesting. Hou, J., Ma, Y., Li, S., Shi, J., He, L., Li, J., 2018. Transformation of sulfur and nitrogen during Shenmu coal pyrolysis. Fuel 231, 134-144. of sulfur and nitrogen and properties of pyrolysates (semicoke, retorting gas, coal tar) during Shenmu coal pyrolysis were investigated using XPS, TG-FTIR-MS, GC–MS and GC-PFPD. The results showed that total sulfur content in the semicoke decreased gradually and turned to sulfate sulfur and thiophenic sulfur with increasing pyrolysis temperature. In Shenmu coal, predominant nitrogen species consisted of pyrrolic and pyridinic compounds. Total nitrogen content was decreased, resulting from mutual conversion of different nitrogen compounds. The composition of retorting gas from TG-FTIR indicated that H2S began to release at 400?°C and reached maximum at about 600?°C. This trend was consistent with the release of carbonyl sulfide (500–650?°C) and SO2. GC-PFPD analysis revealed that detected sulfur compounds in coal tar were benzothiophene, dibenzothiophene and thiophene with the contents of 0.141%, 0.110% and 0.0004%, respectively. In coal tar, 57 kinds of nitrogen-containing compounds were identified using GC–MS, in which basic nitrogen was 0.90% and non-basic nitrogen was 0.23%.Hou, J., Tian, Q., Wang, M., 2018. Variable apparent hydrogen isotopic fractionation between sedimentary n-alkanes and precipitation on the Tibetan Plateau. Organic Geochemistry 122, 78-86. hydrogen isotope ratio values of sedimentary leaf wax n-alkanes (δDwax) have been considered a reliable proxy for precipitation isotope ratios (δDP) across various transects on a global basis. Records of δDwax have been used to infer past changes in hydrology, climate and altimetry, assuming nearly constant apparent hydrogen isotopic fractionation (εwax-P) between sedimentary leaf wax components and precipitation. Here, we present the results of an analysis of δDwax values from the surface sediments of 22 lakes across a precipitation and vegetation gradient on the Tibetan Plateau. The δDwax values correlated significantly with mean annual precipitation δD (r 0.90) and summer precipitation δD (r 0.91), suggesting that δDwax can record δDP in very dry regions. However, εwax-P varies with annual precipitation as well as with relative humidity. Calculation using Craig-Gordon isotope models showed that the variable εwax-P values likely resulted from intensive soil evaporation and plant evapotranspiration in this relatively arid region. This implies that variable isotopic fractionation should be taken into consideration when reconstructing paleohydrology, paleoclimate and paleoaltimetry.Hou, X., Wu, Y., Wang, Z., Liu, Y., 2018. Study on characterization and mechanism of thermal evolution of Green River shale kerogen by flash stepwise pyrolysis. Acta Sedimentologica Sinica 36, 630-638. stepwise pyrolysis provide more efficient information than the simple one step pyrolysis for the same samples. This technique could be used to study on the specific thermal evolution trends of kerogen (or other samples) and its changes of structural characteristics effectively with temperature increased. In this study, thermal simulation analysis of was carried out by flash stepwise pyrolysis on the kerogen samples of the Green River shale at seven heating temperatures separatedly. There was almost no pyrolysed products at 300℃ while a little absorbed hydrocarbons appeared at 350℃. Three pyrolysis temperatures were enriched in pyrolysates at 400℃, 450℃and 500℃, respectively, and the pyrolysis products reached a peak at 450℃. The products were mainly in pairs of n-alkanes and n-alkenes, accompanied by the gradual reduction of isoprenoids and long carbon hydrocarbons, prist-1-ene was the dominated single component at both 400℃and 450℃.; There were only a very small quantity of hydrocarbons liberated at 550℃. After 600℃, pyrolysates almost disappeared, indicating the thermal cracking mainly occurred at lower temperatures. These results may demonstrate that the pyrolysates by flash stepwise pyrolysis at temperatures from 300℃ to 600℃ with an interval of 50℃ could provide enough information for the study of thermal evolution and hydrocarbon generation mechanism of kerogen.Hu, P., Chen, D., Zi, M., Wu, G., 2018. Effects of carbon steel corrosion on the methane hydrate formation and dissociation. Fuel 230, 126-133. surface corrosion and gas hydrate plugging are two tricky problems with security risks to the oil-gas production and transportation. The surface morphology, induction time, normalized formation rate and percentage conversion of water to methane hydrate were in situ monitored on the carbon steel (CS) coupon inserted in the SDS solution, which was corroded by soaking in the seawater for different times (0–336?h) before use. The water distribution and methane hydrate cages formation on the metal surfaces with different physical structures were also investigated by microsecond molecular dynamics (MD) simulation. Results indicated that the presence of CS coupons could facilitate the hydrate nucleation via reducing the induction time by about 37%. CS corrosion led to 60% decrease in the induction time compared with the pristine CS, but insignificant difference was found for the CS coupons with different corrosion time. Moreover, the CS coupons had insignificant effects on the normalized hydrate formation rate, but were able to significantly enhance the percent conversion of water to hydrate and inhibit the hydrate dissociation. Overall tendency observed from experiments agreed with the MD simulations, which highlighted the contribution of the changes in the physical structure (formation of grooves with different sizes) other than the chemical components (formation of rust) to the hydrate formation.Hu, Q., Xie, Z., Wang, X., Kang, H., Zhang, Y., Ding, X., Zhang, P., 2018. Monocarboxylic and dicarboxylic acids over oceans from the East China Sea to the Arctic Ocean: Roles of ocean emissions, continental input and secondary formation. Science of The Total Environment 640–641, 284-292. acids are major components in marine organic aerosols. Many studies on the occurrence, sources and sinks of organic acids over oceans in the low and middle latitudes have been conducted. However, the understanding of relative contributions of specific sources to organic acids over oceans, especially in the high latitudes, is still inadequate. This study measured organic acids, including C14:0 – C32:0 saturated monocarboxylic acids (MCAs), C16:1, C18:1 and C18:2 unsaturated MCAs, and di-C4 – di-C10 dicarboxylic acids (DCAs), in the marine boundary layer from the East China Sea to the Arctic Ocean during the 3rd Chinese Arctic Research Expedition (CHINARE 08). The average concentrations were 18?±?16?ng/m3 and 11?±?5.4?ng/m3 for ΣMCA and ΣDCA, respectively. The levels of saturated MCAs were much higher than those of unsaturated DCAs, with peaks at C16:0, C18:0 and C14:0. DCAs peaked at di-C4, followed by di-C9 and di-C8. Concentrations of MCAs and DCAs generally decreased with increasing latitudes. Sources of MCAs and DCAs were further investigated using principal component analysis with a multiple linear regression (PCA-MLR) model. Overall, carboxylic acids originated from ocean emissions, continental input (including biomass burning, anthropogenic emissions and terrestrial plant emissions), and secondary formation. All the five sources contributed to MCAs with ocean emissions as the predominant source (48%), followed by biomass burning (20%). In contrast, only 3 sources (i.e., secondary formation (50%), anthropogenic emissions (41%) and biomass burning (9%)) contributed to DCAs. Furthermore, the sources varied with regions. Over the Arctic Ocean, only secondary formation and anthropogenic emissions contributed to MCAs and DCAs.Huang, C., Joachimski, M.M., Gong, Y., 2018. Did climate changes trigger the Late Devonian Kellwasser Crisis? Evidence from a high-resolution conodont record from South China. Earth and Planetary Science Letters 495, 174-184. impact of climate change on biodiversity has been the focus of studies on the Phanerozoic biotic crises. However, it is still controversial whether climate change has caused the Frasnian–Famennian (F–F) biotic crisis since there is no unequivocal view on the global climate change during this critical period. In order to reconstruct palaeotemperatures during the F–F transition in South China (eastern Palaeotethys), a high-resolution oxygen isotope (δ18OPO4) record was obtained based on 104 measurements of conodont apatite from the Yangdi section. The oxygen isotope record based on mono-generic samples reveals an increase in δ18OPO4 by 0.7‰ in the Lower Kellwasser horizon (LKH) and 1.4‰ in the Upper Kellwasser horizon (UKH), translating into low-latitude surface water cooling of ～3 °C and ～6?°C, respectively. These two δ18OPO4 shifts agree well with the time-equivalent δ18OPO4 records from the western Palaeotethys, suggesting that two climate cooling pulses in conjunction with the deposition of the Kellwasser horizons are a global signal during the F–F transition. The positive shift of δ18OPO4δ18OPO4 coincides with positive excursion in carbon isotope of carbonates (δ13Ccarb) in the UKH, indicating that enhanced burial of organic carbon resulted in a drop in atmospheric pCO2 and thus global climate cooling. Cooling started immediately before the Upper Kellwasser biotic crisis, with the lowest temperature documented at the top of the UKH. Climate cooling during the deposition of the LKH is observed in conjunction with the sharp decline in metazoan reefs. The coincidence of cooling and the Kellwasser biotic crisis suggests that global cooling played a major role in the collapse of ecosystems.Huang, C., Song, J., Shen, J., Gong, Y., 2018. The influence of the Late Devonian Kellwasser events on deep-water ecosystems: Evidence from palaeontological and geochemical records from South China. Palaeogeography, Palaeoclimatology, Palaeoecology 504, 60-74. Late Devonian Frasnian–Famennian (F–F) event, consisting of the Lower and Upper Kellwasser events, had a severe impact on shallow-water ecosystems, while the effect on deep-water ecosystems is ambiguous. In order to recognize the Kellwasser events and to evaluate their influences on the deep-water ecosystems, a newly refined conodont biostratigraphic framework spanning the Lower Palmatolepis rhenana Zone to the Pa. delicatula platys Zone has been established in the Nandong section (basinal facies), Guangxi, South China. The Upper Devonian Lower and Upper Kellwasser horizons (LKH and UKH) have been recognized in the deep-water facies on the basis of lithological variations, biological turnovers, and positive carbon isotope (δ13Ccarb) excursions. The LKH is characterized by the enrichment of marine nektonic communities (e.g. conodonts, homoctenids, and entomozoacean ostracods), whereas the top of the UKH is barren of fossil organisms, suggesting that the Upper Kellwasser event had a more severe effect on nekton than the Lower Kellwasser event. The Upper Kellwasser (UK) δ13Ccarb positive excursion lags behind the enrichment of Cu, Ni, Mo and V, indicating that the UK δ13Ccarb positive excursion was probably related to elevated primary productivity, which induced oxygen depletion in the water column. The UK δ13Ccarb positive excursion peak prior to the F–F boundary indicates a more limited effect of riverine influx on the deep-water setting, which suggests that the regional palaeogeographic configuration played an important role in the carbon cycle.Huang, D., Duan, Y., Yang, G., Yan, W., Wei, T., Zou, J., Wang, W., Li, Y., 2018. Controlling effect of source-reservoir configuration model on tight oil enrichment in freshwater lacustrine sedimentary area:a case study of the Jurassic Da’anzhai Member in Sichuan Basin. Acta Petrolei Sinica 39, 518-527. Jurassic Da'anzhai Member in Sichuan Basin is a type of typical freshwater lacustrine facies, and the pre-evaluated tight oil resources is as high as 9×108 tons, indicating a great prospect of exploration and development. Based on the analysis of source rock and reservoir characteristics in combination with a large number of production dynamic data, this study emphatically analyzes the controlling effect of source-reservoir configurations on tight oil rich area in the freshwater lacustrine sedimentary area. The results show that the relationship between source and storage in this area is controlled by five categories of sedimentary microfacies, i.e., lower thick reservoir-upper thin source, upper thick reservoir-lower thin source, thick reservoir sandwiched with thick source, thin reservoir sandwiched with thick source, and source-reservoir lateral contact. The laboratory simulation shows that the source-reservoir spatial configuration is the key to control the enrichment of tight oil. The exploration and development practice in typical oil fields reveals that the lower thick reservoir-upper thin source under lacustrine sedimentary facies belt is the optimal configuration type, followed by the thick reservoir sandwiched with thick source under shallow lacustrine sedimentary facies belt, whereas the thin reservoir sandwiched with thick source under semi-deep lacustrine sedimentary facies belt is relatively poorer. According to the above source-reservoir configuration models and current exploration and development practice, it can be obtained that the lacustrine sedimentary facies belt is the exploration area for tight oil, while the semi-deep lacustrine sedimentary facies zone is the exploration area of shale oil and gas. The above knowledge lays a solid foundation for the exploration, development and evaluation of tight oil and shale hydrocarbons in this area.Huang, H., Sun, W., Xiong, F., Chen, L., Li, X., Gao, T., Jiang, Z., Ji, W., Wu, Y., Han, J., 2018. A novel method to estimate subsurface shale gas capacities. Fuel 232, 341-350. order to evaluate shale gas content more accurately, a novel method for estimation of shale gas content in place is proposed based on the Polanyi adsorption potential and the London dispersion potential energy (P-L method). A series of integrated analyses were conducted on one shale core sample from the 7th member of Yanchang Formation (Chang 7 Member) in Ordos Basin, NW China, including on-site canister desorption tests, high-pressure methane adsorption isotherms, helium-based porosimetry, and gas composition analysis. On the basis of our experimental results, the P-L method and the commonly used ‘direct’ (based on measurement of desorbed gas) and ‘indirect’ (based on measurement of pore volume and state of equation) methods were used, respectively, to model the in-situ shale gas content. The results show that the shale gas content under the same experimental conditions predicted by the P-L method was 4.398?cm3/g and that by the direct method was 1.668?cm3/g, which is significantly lower. Meanwhile, those under the same lab conditions by the P-L method and the indirect method are 3.954?cm3/g and 3.820?cm3/g, respectively. Direct methods are more sensitive to human errors than the indirect methods, remove the impact of arbitrary factors by operators, and can shed light on the actual shale gas content in place based on the measured properties of samples. The P-L method is supported by well-developed theoretical basis. Through comparison between all these three methods, the results by the P-L method can be reasonable and practicable, and could be used to recover shale gas content in-situ during the shale gas resource potential assessment.Huang, J., Yu, Z., Chistoserdova, L., 2018. Lanthanide-dependent methanol dehydrogenases of XoxF4 and XoxF5 clades are differentially distributed among methylotrophic bacteria and they reveal different biochemical properties. Frontiers in Microbiology 9, 1366. doi: 1310.3389/fmicb.2018.01366. alcohol dehydrogenases have recently emerged as environmentally important enzymes, most prominently represented in methylotrophic bacteria. The diversity of these enzymes, their environmental distribution, and their biochemistry, as well as their evolutionary relationships with their calcium-dependent counterparts remain virtually untapped. Here, we make important advances toward understanding lanthanide-dependent methylotrophy by assessing the distribution of XoxF4 and XoxF5 clades of lanthanide methanol dehydrogenases among, respectively, Methylophilaceae and non-Methylophilaceae methylotrophs, and we carry out comparative biochemical characterization of XoxF4 and XoxF5 enzymes, demonstrating differences in their properties, including catalytic efficiencies. We conclude that one subtype of the XoxF4 enzyme, XoxF4-1 is the dominant type in nature while other XoxF4 subtypes appear to be auxiliary, representatives of this clade only found in the Methylophilaceae (Betaproteobacteria). In contrast, we demonstrate that XoxF5 enzymes are widespread among Alpha-, Beta-, and Gammaproteobacteria. We purified and biochemically characterized two XoxF4 enzymes (XoxF4-1 and XoxF4-2), both from Methylotenera mobilis, and one XoxF5 enzyme, from Methylomonas sp., after expressing their His-tagged versions in respective natural hosts. All three enzymes showed broad specificities toward alcohols and aldehydes and strict dependence on lighter lanthanides. However, they revealed differences in their properties in terms of optimal pH for in vitro activity, ammonia dependence, the range of lanthanides that could serve as cofactors, and in kinetic properties. Overall, our data advance the understanding of the biochemistry and environmental distribution of these recently discovered enzymes that appear to be key enzymes in lanthanide-dependent methylotrophy.Huang, S., Wu, Y., Cheng, L., Liu, H., Xue, Y., Ding, G., 2018. Apparent permeability model for shale gas reservoirs considering multiple transport mechanisms. Geofluids 2018, Article 2186194. formation is featured in nanopores and much gas adsorptions. Gas flow in the shale matrix is not a singular viscous flow, but a combination of multiple mechanisms. Much work has been carried out to analyze apparent permeability of shale, but little attention has been paid to the effect of unique gas behavior in nanopores at high pressure and adsorbed layer on apparent permeability. This work presents a new model considering multiple transport mechanisms including viscous flow (without slip), slip flow, Knudsen diffusion, and surface diffusion in the adsorption layer. Pore diameter and mean free path of gas molecules are corrected by considering the adsorption layer and dense gas effect, respectively. Then the effects of desorption layer, surface diffusion, and gas behavior on gas apparent permeability in nanopores of shale are analyzed. The results show that surface diffusion is the dominant flow mechanism in pores with small diameter at low pressure and that the effect of adsorbed layer and dense gas on apparent permeability is strongly affected by pressure and pore diameter. From the analysis results, the permeability value calculated with the new apparent permeability model is lower than in the other model under high pressure and higher than in the other model under high pressure, so the gas production calculated using the new permeability model will be lower than using the other model at early stage and higher than using the other model at late stage.Huang, S., Zhang, Y., Sheng, J.J., 2018. Experimental investigation of enhanced oil recovery mechanisms of air injection under a low-temperature oxidation process: Thermal effect and residual oil recovery efficiency. Energy & Fuels 32, 6774-6781. air injection process (AIP) has been applied as an enhanced oil recovery (EOR) method in the light oil reservoir for decades. When high-temperature combustion reactions cannot be achieved, the low-temperature oxidation (LTO) reactions will dominate the AIP. The exothermic intensity of LTO reactions is much milder than that of high-temperature combustion reactions, which caused the thermal effect of the LTO reactions to be underestimated by researchers for a long time. Besides the thermal effect, questions such as whether LTO reactions could improve recovery efficiency and whether the LTO reactions could produce residual oil from the reservoir need to be answered. In this study, a series of isothermal core flooding tests under different environmental temperature conditions were applied to study the thermal effect on oil recovery. In addition, alternate injection of nitrogen and air was performed to study the LTO effect on oil recovery besides the thermal effect. The experimental results showed that the thermal effect can play a significant role on recovery performance because a higher temperature results in a higher oil recovery factor, where a temperature increment of 40 °C by the LTO reactions can result in a 10% recovery factor increase. On the other side, the LTO effect on producing residual oil was not observed in this study. Moreover, despite the thermal effect, the LTO-generated oxygenated compounds will increase the viscosity of the crude oil, which will decrease the recovery efficiency. Therefore, because the thermal effect of LTO works against the viscosity increment effect of LTO, the AIP is recommended only if the thermal effect is more significant compared to the increased viscosity effect in terms of recovery efficiency.Huang, X., Guo, X., Lu, X., Zhou, X., Qi, Z., Yan, W., Li, J., 2018. Mathematical model study on the damage of the liquid phase to productivity in the gas reservoir with a bottom water zone. Petroleum 4, 209-214. production process in the gas reservoir with an aquifer is complex. With gas production, aquifer water could possibly flow into the production well and accumulate within the well bore, which leads to a lower production rate and may even block the producer. However, few studies in the literature investigate the damage caused by the liquid phase in this kind of reservoir or predict gas productivity using the relationship between reservoir pressure and water gas ratio (WGR). For this reason, it is important to know the effects of the formation of liquid phase behavior on production when an aquifer is present under a gas reservoir.From the results of published literature reviews, we found that studies focused on the production of a gas reservoir with bottom water. Nevertheless, for gas well damage from the liquid phase behavior, we found that there was no statistical data or mathematical model of the relationship between reservoir pressure and the gas oil ratio (GOR), which affects production.In this research, based on the theory of fluid flow in porous media, a new mathematical model of water and gas production and a new equation on gas well productivity is developed. To verify the model and equation, gas production data collected from the field are applied. By analyzing the typical gas reservoir with bottom water and the collected data, influences from the liquid phase behavior are shown. In this way, mathematical relationships between reservoir pressure and the WGR and between the GOR and production decline were obtained. The new gas productivity model is derived from the gas and water pseudo pressure functions, which can be applied to analyze well damage caused by the liquid phase.In order to verify the mathematical model, production data were collected from a typical gas reservoir with an aquifer located in the Changxing gas reservoir. The results indicate that a semi-logarithmic linear relationship is obtained between the WGR and productivity decrease. When the WGR increases from 0.5 to 15?m3/104?m3, damage caused by liquid phase decreases to 59%.The tendency of gas productivity in the Changxing gas reservoir was obtained so that it decreases as reservoir pressure decreases and increases as the WGR decreases. The gradient of the gas productivity deduction increases as the WGR increases. By the end of the data analysis, two linear equations indicating the relationship between gas productivity and reservoir pressure and the relationship between gas productivity and the water gas ratio are obtained: QAOF=?A1lnWGR?B1 and ?QAOF=A2lnP?B2, respectively.The new model and these two equations can be applied to predict gas productivity in the gas reservoir with an aquifer and determine the damage level to the gas well. They also can be used to guide development plans in the gas reservoir with an aquifer.Hughes, L.C., Ortí, G., Huang, Y., Sun, Y., Baldwin, C.C., Thompson, A.W., Arcila, D., Betancur-R, R., Li, C., Becker, L., Bellora, N., Zhao, X., Li, X., Wang, M., Fang, C., Xie, B., Zhou, Z., Huang, H., Chen, S., Venkatesh, B., Shi, Q., 2018. Comprehensive phylogeny of ray-finned fishes (Actinopterygii) based on transcriptomic and genomic data. Proceedings of the National Academy of Sciences 115, 6249.. Ray-finned fishes form the largest and most diverse group of vertebrates. Establishing their phylogenetic relationships is a critical step to explaining their diversity. We compiled the largest comparative genomic database of fishes that provides genome-scale support for previous phylogenetic results and used it to resolve further some contentious relationships in fish phylogeny. A vetted set of exon markers identified in this study is a promising resource for current sequencing approaches to significantly increase genetic and taxonomic coverage to resolve the tree of life for all fishes. Our time-calibrated analysis suggests that most lineages of living fishes were already established in the Mesozoic Period, more than 65 million years ago.Abstract. Our understanding of phylogenetic relationships among bony fishes has been transformed by analysis of a small number of genes, but uncertainty remains around critical nodes. Genome-scale inferences so far have sampled a limited number of taxa and genes. Here we leveraged 144 genomes and 159 transcriptomes to investigate fish evolution with an unparalleled scale of data: >0.5 Mb from 1,105 orthologous exon sequences from 303 species, representing 66 out of 72 ray-finned fish orders. We apply phylogenetic tests designed to trace the effect of whole-genome duplication events on gene trees and find paralogy-free loci using a bioinformatics approach. Genome-wide data support the structure of the fish phylogeny, and hypothesis-testing procedures appropriate for phylogenomic datasets using explicit gene genealogy interrogation settle some long-standing uncertainties, such as the branching order at the base of the teleosts and among early euteleosts, and the sister lineage to the acanthomorph and percomorph radiations. Comprehensive fossil calibrations date the origin of all major fish lineages before the end of the Cretaceous.Husinec, A., Read, J.F., 2018. Cyclostratigraphic and δ13C record of the Lower Cretaceous Adriatic Platform, Croatia: Assessment of Milankovitch-forcing. Sedimentary Geology 373, 11-31. 700-m-thick Hauterivian to Albian section from the interior of the large, Adriatic Platform is exposed on Mljet and Kor?ula islands, Croatia. The cyclic platform consists of meter-scale parasequences, bundled into parasequence sets, superbundles and then into breccia-bounded depositional sequences. Spectral analysis of time series (cycle number vs. cycle thickness) shows peaks in the short-term eccentricity (95 to 130?kyr) bands and 160 to 200?kyr bands. Isotope samples from micrite matrix of mudstone and wackestone have δ13C values generally from ?1.5 to +2‰ VPDB, and δ18O from ?1 to ?3.5‰ VPDB. Adriatic Platform δ13C values are shifted ~2‰ VPDB more negative than marine pelagic values. A δ13C and δ18O meteoric signal is limited to just beneath sequence boundaries, suggesting that the isotopic shift is due mainly to marine phreatic‐ and synorogenic burial diagenesis. Major excursions on the 5-point smoothed δ13C profile of the Adriatic Platform, tied biostratigraphically to δ13C curves from pelagic sections, include the oceanic anoxic events OAE1a, 1b, and 1c. Time series constructed from δ13C values (unsmoothed data) vs. stratigraphic position show peaks in the Milankovitch band, especially short-term eccentricity. Most positive peaks are near parasequence set boundaries (50 to 60%) and regressive parts of parasequences (20%). Although diagenetically shifted, the δ13C record retains a highly clipped memory of astronomically-driven global δ13C fluctuations albeit modified by platform water restriction during cyclic deposition.Huttenlocker, A.K., Grossnickle, D.M., Kirkland, J.I., Schultz, J.A., Luo, Z.-X., 2018. Late-surviving stem mammal links the lowermost Cretaceous of North America and Gondwana. Nature 558, 108-112. was a successful clade of mammaliaforms, spanning the Late Triassic period to at least the Late Jurassic period, but their fossils are scant outside Eurasia and Cretaceous records are controversial. Here we report, to our knowledge, the first cranium of a large haramiyidan from the basal Cretaceous of North America. This cranium possesses an amalgam of stem mammaliaform plesiomorphies and crown mammalian apomorphies. Moreover, it shows dental traits that are diagnostic of isolated teeth of supposed multituberculate affinities from the Cretaceous of Morocco, which have been assigned to the enigmatic ‘Hahnodontidae’. Exceptional preservation of this specimen also provides insights into the evolution of the ancestral mammalian brain. We demonstrate the haramiyidan affinities of Gondwanan hahnodontid teeth, removing them from multituberculates, and suggest that hahnodontid mammaliaforms had a much wider, possibly Pangaean distribution during the Jurassic–Cretaceous transition.Igder, M., Hosseinpour, N., Biyouki, A.A., Bahramian, A., 2018. Control of asphaltene aggregation in reservoir model oils along the production streamline by Fe3O4 and NiO nanoparticles. Energy & Fuels 32, 6689-6697. oxide (Fe3O4) and nickel oxide (NiO) nanoparticles were employed to control the aggregation of asphaltenes in reservoir model oils along the production streamline from the far-field region to near-wellbore area to wellbore conditions. Fe3O4 and NiO nanoparticles with an average particle size of 30 and 78 nm, respectively, were synthesized via a simple precipitation method and characterized by X-ray diffraction, Brunauer, Emmett, and Teller (BET), Fourier transform infrared spectroscopy, and field emission scanning electron microscopy imaging techniques. Asphaltenes were extracted from an Iranian heavy oil sample, and their structure and functional groups were characterized. The asphaltenes were dissolved in toluene at a concentration of 400 mg/L, designated as reservoir model oil. The average size of the asphaltene nanoaggregates in the model oil, as determined by dynamic light scattering (DLS), is 18 nm, representative of the size of asphaltene aggregates in reservoir oils. The nanoparticles were added to the model oil at an optimum ratio of 0.09 m2 BET surface area/g of the asphaltenes, and the samples were shaken at 70 rpm to approach equilibrium. In order to simulate the effects of pressure depletion on aggregation of asphaltenes at far-field conditions, n-heptane was added at different volume ratios to the thus-obtained equilibrium model oil followed by shaking to approach a new equilibrium, designated as far-field tests. The equilibrium samples obtained from the far-field tests were exposed to shear stress in a flow assurance apparatus to simulate the effects of shear rate on aggregation/fragmentation of asphaltenes at near-wellbore/wellbore conditions, classified as near-wellbore tests. The Couette–Taylor flow assurance apparatus consists of two concentric cylinders, and the fluid in the annular space is subjected to shear stress by rotation of the internal cylinder. In order to determine the size distribution of the asphaltene aggregates at the far-filed and near-wellbore conditions, the samples were exposed to a magnetic field or centrifugation, and the supernatant liquids were subjected to dynamic light scattering analysis. It is found from the far-field tests that the asphaltenes onset point, i.e., the average aggregate size of 500 nm, is obtained at 21, 29, and 45 vol % of n-C7 in the absence of the nanoparticles, in the presence of NiO and in the presence of Fe3O4, respectively. The higher activity of the Fe3O4 nanoparticles for the control of the asphaltene aggregation is attributed to the number and strength of the interactions of the asphaltenes’ functional groups with the surface sites of the nanoparticles. Furthermore, the near-wellbore test results show that the shear stress leads to aggregation where the size of the asphaltene nanoaggregates is smaller than around 50 nm. Fragmentation of the asphaltene aggregates is the result of shear stress for samples with aggregates sizes of higher than about 50 nm. This may be ascribed to the effects of the shear stress on the development of electrostatic fields (aggregation) as well as fragmentation (break up) of the asphaltene aggregates in the model oils.Igisu, M., Yokoyama, T., Ueno, Y., Nakashima, S., Shimojima, M., Ohta, H., Maruyama, S., 2018. Changes of aliphatic C–H bonds in cyanobacteria during experimental thermal maturation in the presence or absence of silica as evaluated by FTIR microspectroscopy. Geobiology 16, 412-428. C–H bonds are one of the major organic signatures detected in Proterozoic organic microfossils, and their origin is a topic of interest. To investigate the influence of the presence of silica on the thermal alteration of aliphatic C–H bonds in prokaryotic cells during diagenesis, cyanobacteria Synechocystis sp. PCC6803 were heated at temperatures of 250–450°C. Changes in the infrared (IR) signals were monitored by micro‐Fourier transform infrared (FTIR) spectroscopy. Micro‐FTIR shows that absorbances at 2,925 cm?1 band (aliphatic CH2) and 2,960 cm?1 band (aliphatic CH3) decrease during heating, indicating loss of the C–H bonds, which was delayed by the presence of silica. A theoretical approach using solid‐state kinetics indicates that the most probable process for the aliphatic C–H decrease is three‐dimensional diffusion of alteration products under both non‐embedded and silica‐embedded conditions. The extrapolation of the experimental results obtained at 250–450°C to lower temperatures implies that the rate constant for CH3 (kCH3) is similar to or lower than that for CH2 (kCH2; i.e., CH3 decreases at a similar rate or more slowly than CH2). The peak height ratio of 2,960 cm?1 band (CH3)/2,925 cm?1 band (CH2; R3/2 values) either increased or remained constant during the heating. These results reveal that the presence of silica does affect the decreasing rate of the aliphatic C–H bonds in cyanobacteria during thermal maturation, but that it does not significantly decrease the R3/2 values. Meanwhile, studies of microfossils suggest that the R3/2 values of Proterozoic prokaryotic fossils from the Bitter Springs Group and Gunflint Formation have decreased during fossilization, which is inconsistent with the prediction from our experimental results that R3/2 values did not decrease after silicification. Some process other than thermal degradation, possibly preservation of specific classes of biomolecules with low RR3/2 values, might have occurred during fossilization. Ishii, E., 2018. Assessment of hydraulic connectivity of fractures in mudstones by single-borehole investigations. Water Resources Research 54, 3335-3356. Assessing the hydraulic connectivity of fractures by single-borehole investigations is crucial to radioactive waste disposal but is still a challenge as such connectivity is difficult to measure directly. This study presents geological, hydrological, hydrochemical, and rock-mechanical data for three faulted/fractured mudstones (the Koetoi, Wakkanai, and Palfris Formations) and proposes a new methodology for assessing the hydraulic connectivity of fractures. The methodology consists of three steps: (a) dividing the formation into two domains with a ductility index (DI) of >2 and <2 (DI is defined as the effective mean stress normalized to the tensile strength of intact rock), (b) estimating the hydraulic connectivity of fractures by analyzing pressure change obtained by packer tests and geological interpretation, and (c) verifying the estimation using pore pressure and water chemistry/geochemistry. The first step is necessary because the failure mode of damage-zone fractures in fault zones can differ between the DI?>?2 and DI?<?2 domains, which may lead to significant differences in the hydraulic connectivity of fractures. During the second step, potential domains in which the hydraulic connectivity of fractures is limited are identified where upward trends, characterized by slopes of ?0.5?1.0, are observed during the middle to late period of elapsed time on log-log plots of pressure derivatives. Although the third step can be performed in various ways, this study employs the observation of pressure anomalies and the detection of young external water. Analyses of the three formations demonstrate the applicability and reliability of the proposed methodology.Ishii, H.A., Bradley, J.P., Bechtel, H.A., Brownlee, D.E., Bustillo, K.C., Ciston, J., Cuzzi, J.N., Floss, C., Joswiak, D.J., 2018. Multiple generations of grain aggregation in different environments preceded solar system body formation. Proceedings of the National Academy of Sciences 115, 6608-6613.: The initial solids from which the solar system formed consisted almost entirely of amorphous silicate, carbon, and ices. This dust was mostly destroyed and reworked by processes that led to the formation of planets. Surviving samples of presolar dust are most likely to be preserved in comets, small cold bodies that formed in the outer solar nebula. In interplanetary dust particles originating from comets, we observe organic carbon mantles on subgrains within amorphous-silicate?dominated grains called GEMS (glass with embedded metal and sulfides). Our observations constrain GEMS grain formation to cold and radiation-rich environments, making a compelling case that these exotic grains, unique to a relatively obscure class of extraterrestrial material, are surviving dust from (variable) interstellar environments and thus the original building materials of planetary systems.Abstract: The solar system formed from interstellar dust and gas in a molecular cloud. Astronomical observations show that typical interstellar dust consists of amorphous (a-) silicate and organic carbon. Bona fide physical samples for laboratory studies would yield unprecedented insight about solar system formation, but they were largely destroyed. The most likely repositories of surviving presolar dust are the least altered extraterrestrial materials, interplanetary dust particles (IDPs) with probable cometary origins. Cometary IDPs contain abundant submicron a-silicate grains called GEMS (glass with embedded metal and sulfides), believed to be carbon-free. Some have detectable isotopically anomalous a-silicate components from other stars, proving they are preserved dust inherited from the interstellar medium. However, it is debated whether the majority of GEMS predate the solar system or formed in the solar nebula by condensation of high-temperature (>1,300 K) gas. Here, we map IDP compositions with single nanometer-scale resolution and find that GEMS contain organic carbon. Mapping reveals two generations of grain aggregation, the key process in growth from dust grains to planetesimals, mediated by carbon. GEMS grains, some with a-silicate subgrains mantled by organic carbon, comprise the earliest generation of aggregates. These aggregates (and other grains) are encapsulated in lower-density organic carbon matrix, indicating a second generation of aggregation. Since this organic carbon thermally decomposes above ～450 K, GEMS cannot have accreted in the hot solar nebula, and formed, instead, in the cold presolar molecular cloud and/or outer protoplanetary disk. We suggest that GEMS are consistent with surviving interstellar dust, condensed in situ, and cycled through multiple molecular clouds.Isson, T.T., Love, G.D., Dupont, C.L., Reinhard, C.T., Zumberge, A.J., Asael, D., Gueguen, B., McCrow, J., Gill, B.C., Owens, J., Rainbird, R.H., Rooney, A.D., Zhao, M.Y., Stueeken, E.E., Konhauser, K.O., John, S.G., Lyons, T.W., Planavsky, N.J., 2018. Tracking the rise of eukaryotes to ecological dominance with zinc isotopes. Geobiology 16, 341-352. biogeochemical cycling of zinc (Zn) is intimately coupled with organic carbon in the ocean. Based on an extensive new sedimentary Zn isotope record across Earth's history, we provide evidence for a fundamental shift in the marine Zn cycle ~800 million years ago. We discuss a wide range of potential drivers for this transition and propose that, within available constraints, a restructuring of marine ecosystems is the most parsimonious explanation for this shift. Using a global isotope mass balance approach, we show that a change in the organic Zn/C ratio is required to account for observed Zn isotope trends through time. Given the higher affinity of eukaryotes for Zn relative to prokaryotes, we suggest that a shift toward a more eukaryote‐rich ecosystem could have provided a means of more efficiently sequestering organic‐derived Zn. Despite the much earlier appearance of eukaryotes in the microfossil record (~1700 to 1600 million years ago), our data suggest a delayed rise to ecological prominence during the Neoproterozoic, consistent with the currently accepted organic biomarker records. Jaiswal, D., Prasannan, C.B., Hendry, J.I., Wangikar, P.P., 2018. SWATH tandem mass spectrometry workflow for quantification of mass isotopologue distribution of intracellular metabolites and fragments labeled with isotopic 13C carbon. Analytical Chemistry 90, 6486-6493. quantification of mass isotopologue distribution (MID) of metabolites is a prerequisite for 13C-metabolic flux analysis. Currently used mass spectrometric (MS) techniques based on multiple reaction monitoring (MRM) place limitations on the number of MIDs that can be analyzed in a single run. Moreover, the deconvolution step results in amplification of error. Here, we demonstrate that SWATH MS/MS, a data independent acquisition (DIA) technique allows quantification of a large number of precursor and product MIDs in a single run. SWATH sequentially fragments all precursor ions in stacked mass isolation windows. Co-fragmentation of all precursor isotopologues in a single SWATH window yields higher sensitivity enabling quantification of MIDs of fragments with low abundance and lower systematic and random errors. We quantify the MIDs of 53 precursor and product ions corresponding to 19 intracellular metabolites from a dynamic 13C-labeling of a model cyanobacterium, Synechococcus sp. PCC 7002. The use of product MIDs resulted in an improved precision of many measured fluxes compared to when only precursor MIDs were used for flux analysis. The approach is truly untargeted and allows additional metabolites to be quantified from the same data.Jambrina-Enríquez, M., Herrera-Herrera, A.V., Mallol, C., 2018. Wax lipids in fresh and charred anatomical parts of the Celtis australis tree: Insights on paleofire interpretation. Organic Geochemistry 122, 147-160. waxes have been assumed to be the dominant source of wax delivered to sediment. However, wooden branches and twigs have not been widely considered in this context and could be a potential source of wax lipids in fire places or combustion structures. Black sedimentary layers are the main material of open-air archaeological combustion structures and represent either carbonized fuel (wood) or the charred ground beneath the fire (mainly leaves) and it is difficult to discern between the two sources. To identify different plant parts as components of combustion residues, fresh and charred leaves, branches and twigs (bark and xylem) of the Celtis australis tree were analyzed for aliphatic and aromatic hydrocarbons and fatty acid concentrations, as well as the carbon isotopic composition of n-alkanes (δ13Calkane). Charred biomass was produced under limited oxygen conditions at 150, 250 (3 and 5?h), 350 and 450?°C for 1?h. The n-alkyl profiles in different parts of C. australis are sufficiently distinct to allow their identification as components of combustion structures under low combustion temperature conditions. Average chain lengths and carbon preference index ratios decrease with increasing temperature and vary among plant parts. The δ13Calkane values remained slightly unaltered up to 350?°C and changed by 3–4‰ at 450?°C. Our results provide new information on the molecular and isotopic changes that occur upon burning different plant parts, which in turn show potential for good preservation of organic matter in archaeological black layers and for positive identification of burned leaf and wood residues in them.Jansen, J., Hill, N.A., Dunstan, P.K., Eléaume, M.P., Johnson, C.R., 2018. Taxonomic resolution, functional traits, and the influence of species groupings on mapping Antarctic seafloor biodiversity. Frontiers in Ecology and Evolution 6, 81. doi: 10.3389/fevo.2018.00081. marine biodiversity on the Antarctic continental shelf is high and unique, yet its distributional patterns are still relatively poorly understood. Some of the main issues are that biological data are sparse, and that many species are rare and seem only weakly related to environmental conditions. Grouping species by taxonomic or functional similarity has historically been used to compensate for missing species identification, to generate a more widespread distribution of data-points, and this practice can help to gain a better understanding of the distribution of biodiversity. However, there are few guidelines on how to group species, the implicit assumptions about species associations in the groups are difficult to validate, and the information loss associated with grouping species is unknown. Here, we analyse whether grouping benthic macrofaunal species by taxonomic or functional similarity preserves distributional patterns seen in species distributions, using a model-based approach called ‘species archetype model’ that groups species or other units based on the similarity in their responses to environmental factors. Using presence-absence data, the species archetype models identify twice as many assemblages when used on the highest taxonomic resolution data, than when applied to taxonomic data at lower resolution (e.g. class) or functional groups based on mobility, feeding type and body shape. Further, confidence in the predictions of either taxonomic or functional groups is far less than for predictions based on the highest taxonomic resolution data. Although using functional groups is often thought to accumulate species with similar environmental responses, our analysis shows that functional groups may insufficiently resolve assemblage structure for presence-absence data. Model-based approaches provide key information to understanding the regional distribution of Antarctic marine biodiversity, and care needs to be taken when using a-priori groupings of species to make statements about the distribution of biodiversity.Javed, S.H., Zahir, A., Azhar, S., Hafeez, K., Abid, S., Nazir, A., Majeed, N., 2018. Physiochemical analysis of selected shale formations of Kohat region by advance characterization for oil potential evaluation. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 40, 1190-1198. current scientific study summarized the physiochemical analysis of shale sample by advance characterization such as Fourier-transform infrared spectroscopy? (FTIR), X-ray diffraction? (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy? to evaluate the energy potential of shale rock pertinent in Kohat region of Pakistan. The samples were collected during the drilling of mines from 1,670 to 4,500 m depth. A total of 21 samples were collected, among which 14 samples were taken from Patala Formation, 4 were from Panoba formation, and 3 were from Kuldana Formation. The proximate analysis was conducted to determine the gross calorific value, moisture, and volatile matters. SEM confirmed the porous surface of shale samples. XRD analysis revealed the presence of quartz, calcite, and plagioclase in the collected shale samples. FTIR tests were conducted to identify functional groups inside the shale samples. It was observed that Panoba Formation has a considerable amount of hydrocarboneous matters with an average value of 6.25%. Patala Formation got lower hydrocarboneous matters than Panoba with an average value of 5.22%, whereas Kuldana Formation contains a hydrocarboneous average value of 3.51%.Jha, N., Aggarwal, N., Mishra, S., 2018. A review of the palynostratigraphy of Gondwana sediments from the Godavari Graben, India: Global comparison and correlation of the Permian-Triassic palynoflora. Journal of Asian Earth Sciences 163, 1-21. continental sequences of Gondwana deposits from the Chintalapudi sub-basin of the Godavari Graben, South India have been palynologically investigated to explore the Permian–Triassic palynoflora. Total 11 distinct palynoassemblages belonging to the Asselian-Sakmarian (I, II), Artinskian (III, IV), Guadalupian (V, VI), Lopingian (VII, VIII, IX), Induan (X) and Olenekian (XI) age have been documented. The palynological studies support the existence of the two coal-bearing horizons in the Chintalapudi sub-basin, one in the Karharbari and Barakar formations (Sakmarian-Artinskian) while other in the Raniganj Formation (Guadalupian-Lopingian). The lack of the Upper Barakar and Barren Measures (Roadian) palynoflora indicates apparent discordance in stratigraphic sequence in this sub-basin. Presently studied the Permian-Triassic palynofloral transition has been found akin to the palynoflora of the Salt Range, Madagascar, Antarctica, Australia and South Africa. The palynofloral correlation supports the presence of Guttulapollenites palaeophytogeographic province in the Gondwana during the Guadalupian– Lopingian. The Guttulapollenites palaeophytogeographic province co-exists with the Glossopteris megafloral province and extends from the Salt Range in the north to Amery Basin in the south, Mid Zambesi-Luangwa Basin in the west to Satpura-Wardha-Godavari Basin in the east.Jia, Z., Hou, D., Sun, D., Jiang, Y., Zhang, H., Han, X., Zhang, Z., Hong, M., Chang, Z., 2018. The intensity evaluation of the hydrothermal sedimentation and the relationship with the formation of organic-rich source rocks in the Lower Cambrian Niutitang Formation in Guizhou Province, China. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 40, 1442-1451. synthetical study was carried out on the relationship between the hydrothermal sedimentation and the formation of organic-rich source rocks in the Lower Cambrian Niutitang Formation in Guizhou Province, China. Analysis of the high trace elemental contents showed that the V/Sc-V/Cr diagram can be used to distinguish the hydrothermal sediments from normal marine sediments. Cr/Sc ratios can quantitatively evaluate the intensity of hydrothermal sedimentation on account of the positive correlation between the ratios with enrichment factors (EFs) for As, Sb and others. The relationship between Cr/Sc ratios and TOC content illustrated that (1) there was a positive linear correlation between them under the low intensity of hydrothermal activities (Cr/Sc<20), and the enrichment and preservation of organic matters were obviously dominated and potentiated by the hydrothermal sedimentation; (2) The hydrothermal sedimentation was one of the most essential factors influencing the enrichment and preservation of organic matters amidst the medium condition (20< Cr/Sc <300); (3) in the high condition (Cr/Sc > 300), the higher the hydrothermal intensity, the less the enrichment and preservation of organic matters, in other words, it is not conducive to the formation of organic-rich source rocks.Jiang, C., Reyes, J., Snowdon, L.R., Milovic, M., Robinson, R., Zhang, S., Armstrong, D., Lavoie, D., 2018. Cyclopentanones and 2-cyclopenten-1-ones as major products of hydrous pyrolysis of immature organic-rich shales. Organic Geochemistry 122, 126-139. is an important platform chemical for various industrial syntheses. It has been recently reported as a major product in biomass cellulose-derived biofuels but has rarely been reported in geochemical research. We report here the abundant occurrence of cyclopentanone, 2-cyclopenten-1-one and their alkyl derivatives in pyrolysates of organic-rich shales. Closed system pyrolyses at temperatures from 290?°C to 350?°C have been carried out on thermally immature organic-rich shale samples of Ordovician and Devonian age from Canada. GC–MS analyses of the pyrolysates show that cyclopentanones, 2-cyclopenten-1-ones and phenols dominate over hydrocarbons in the low temperature hydrous pyrolysates, and their abundance relative to hydrocarbons decreases with increasing thermal maturation. However, these low molecular weight cyclic ketones are only minor components compared with hydrocarbons in anhydrous pyrolysates, indicating that water has played an important role in the formation of these oxygen-containing compounds. In addition, n-alkan-2-ones in the range of C6–C35 are also detected in the hydrous pyrolysates, but they are at much reduced concentrations compared with the cyclic ketones. The potential precursors in the shale and the likely chemical reaction mechanism for the formation of these cyclic ketones are discussed in detail in the paper.Jiang, F., Pang, X., Li, L., Wang, Q., Dong, Y., Hu, Tao, Chen, L., Chen, J., Wang, Y., 2018. Petroleum resources in the Nanpu sag, Bohai Bay Basin, eastern China. American Association of Petroleum Geologists Bulletin 102, 1213-1237. Nanpu sag is an important secondary tectonic division of the Bohai Bay Basin and has an area of 1532 km2 (591 mi2), of which 1000 km2 (386 mi2) has been explored near Bohai. Recently, exploration has gradually shifted from continental to beach to shallow-marine settings, with significant exploration breakthroughs having occurred in the Nanpu 1, 2, and 3 tectonic belts, indicating good resource potential. However, a systematic resource assessment has yet to be performed, which strongly restricts the exploration progress. In this study, we improved upon the Pareto model and reevaluated the area’s resource potential using two new methods. In one method, the traps are divided into several types, including structural, stratigraphic, and buried hill traps, to predict their individual resource potential and total resources of this area; in the other method, the normalized fluid potential is used to divide the area into several accumulation systems to calculate the resource potential. The Nanpu sag resources are estimated at 1.45 × 109 t (10.6 × 109 bbl), which represents an increase of approximately 2.70 × 108 t (19.8 × 108 bbl) compared with previous evaluations because of the increase in exploration maturity and information validation. The main residual resource is distributed in beach to shallow-marine settings. The stratigraphic and buried hill traps present better resource potential using the trap-type method. Such information can guide the direction of exploration and selection of potential traps.Jiang, F., Wang, Q., Liu, L., Gao, X., Hu, T., 2018. Geological and geochemical characteristics of the Middle–Lower Jurassic shales in the Kuqa Depression, Tarim Basin: an evaluation of shale gas resources. Australian Journal of Earth Sciences 65, 557-573.–Lower Jurassic terrigenous shales constitute a set of significant hydrocarbon source rocks in the Kuqa Depression of the Tarim Basin. Until recently, however, most investigations regarding this set of hydrocarbon source rocks have mainly focused on conventional oil and gas reservoirs, and little research has been conducted on the formation conditions of shale gases. This research, which is based on core samples from nine wells in the Kuqa Depression, investigated the geological, geochemical, mineralogical and porosity characteristics of the shales, analysed the geological and geochemical conditions for the formation of shale gases, and evaluated the shale gas resource potential. The results show that the distribution of the Middle–Lower Jurassic shales is broad, with thicknesses reaching up to 300–500 km. The total organic carbon (TOC) content is relatively high, ranging from 0.2 to 13.5 wt% with a mean of 2.7 wt%. The remaining hydrocarbon generative potential is between 0.1 and 22.34 mg/g, with a large range of variation and a mean value of 3.98 mg/g. It is dominated by type III kerogen with the presence of minor type II1 kerogen. The vitrinite reflectance values range from 0.517 to 1.572%, indicating the shales are in a mature or highly mature stage. The shales are mainly composed of quartz (19–76%), clay (18–68%) and plagioclase (1–10%) with mean contents of 50.36 wt%, 41.42 wt%, and 3.37 wt%, respectively. The pore spaces are completely dominated by primary porosity, secondary porosity and microfractures. The porosity is less than 10% and is mainly between 0.5 and 4%, and the permeability is generally less than 0.1 mD. These results classify the shale as a low-porosity and ultra-low-permeability reservoir. The porosity has no obvious correlation with the brittle or clay mineral contents, but it is significantly positively correlated with the TOC content. The maximum adsorbed gas content is between 0.82 and 8.52 m3/t with a mean of 3.37 m3/t. In general, the shale gas adsorption content increases with increasing the TOC content, especially when the TOC content is greater than 1.0%. The volumetric method, used to calculate the geological resources of the Middle–Lower Jurassic shales in the Kuqa Depression, shows that the geological resources of the Middle and Lower Jurassic shales reach 667.681 and 988.115 × 109 m3, respectively with good conditions for the formation of shale gas and good prospects for shale gas exploration.Jiang, T., Sun, X., 2018. Development of Keshen ultra-deep and ultra-high pressure gas reservoirs in the Kuqa foreland basin, Tarim Basin: Understanding points and technical countermeasures. Natural Gas Industry 38, 1-9. Keshen Gas Field in the Kuqa foreland basin, Tarim Basin, is a rare fractured tight sandstone gas reservoir with ultra depth and ultra high pressure. During its pilot period of gas field development, the development effect is poor with a low development well success rate, a low utilization rate of production capacity and a rapid decline of gas well productivity. In view of these problems, development experiments and technological research were carried out continuously after the geological characteristics of gas reservoirs, productivity control factors, reservoir connectivity, seepage characteristics, gas and water relations and water invasion laws were studied thoroughly. And consequently, the development countermeasures of "well placement in high position, moderate stimulation and early-stage drainage" were prepared, and five matching development technologies were formed, such as description technology of ultra deep complex structures, well pattern optimization technology for fractured tight sandstone gas reservoirs, fracture net acid fracturing technology for fractured tight sandstone reservoirs, dynamic monitoring technology for ultra deep and ultra high pressure gas wells, wellbore integrity management and evaluation technology for high pressure gas wells. The following remarkable application results were achieved in the process of gas field development. First, the drilling depth error of the target formation drops from 125 m to less than 30 m. Second, the utilization rate of production capacity in the Keshen 8 Block reaches 100%. Third, the average absolute open flow rate is increased by 5 times to 273×104 m3/d from 50×104 m3/d before the stimulation. Fourth, safe and smooth production under high temperature and high pressure conditions is realized in the Keshen Gas Field. In conclusion, the successful efficient development of the Keshen Gas Field provides the experience for the development of similar gas reservoirs at home and abroad and its development countermeasures and matching technologies have important guidance and reference significance.Jiang, Y., Qin, C., Kang, Z., Zhou, J., Li, Y., Liu, H., Song, X., 2018. Experimental study of supercritical CO2 fracturing on initiation pressure and fracture propagation in shale under different triaxial stress conditions. Journal of Natural Gas Science and Engineering 55, 382-394. carbon dioxide (SC-CO2) fracturing technique used in the development of shale gas has attracted increasing attention in the past decades. Using a self-developed physical simulation system equipped with acoustic emission (AE) and computed tomography (CT) system, the fracture initiation pressure (FIP) and fracture propagation mechanism of shale in the process of SC-CO2 fracturing was invested. The results show that the FIP for the shale without pre-existing fractures obtained from experiment is consistent with the theoretical values under different triaxial stress conditions, indicating that the theoretical calculation for FIP is feasible. The FIP increased gradually with increasing in situ stress for the shale without pre-existing fractures. The pre-existing fractures will affect the FIP and the fracture propagation direction in the shale. AE signals are obviously observed in the fracture initiation and the fracture propagation stages. In addition, the hit, energy, and amplitude are increased stepwise with increasing fracturing time. In the triaxial stress state, the initiation position and the propagation direction of cracks are random in the process of the SC-CO2 fracturing of shale and are along the direction of weak structural planes or pre-existing fractures. The SC-CO2 fracturing technique integrated with AE monitoring and CT scanning can be used to analyse the crack initiation position, the direction and sequence of crack propagation, and the number of the fracturing-generated cracks in shale. This research lays a foundation for SC-CO2 fracturing of shale in the Longmaxi formation in the Sichuan Basin.Jin, L., Pekot, L.J., Hawthorne, S.B., Salako, O., Peterson, K.J., Bosshart, N.W., Jiang, T., Hamling, J.A., Gorecki, C.D., 2018. Evaluation of recycle gas injection on CO2 enhanced oil recovery and associated storage performance. International Journal of Greenhouse Gas Control 75, 151-161. enhanced oil recovery (EOR) technique comprising the alternate injection of gas (CO2) and water, commonly referred to as water alternating gas (WAG) flooding, is currently ongoing at an oil field in the northeastern Powder River Basin (PRB), where 4 million barrels (MMbbl) of oil were produced between May 2013 and September 2017. During WAG flooding, a large amount of CO2, which contains some impurities, is produced at the surface with the recovered oil and reinjected into the reservoir to minimize the amount of purchased CO2. The concentration of these impurities in the CO2, which are dominated by CH4, is a key parameter in the design of miscible CO2 flooding of an oil reservoir and in the quantitative assessment of the associated storage of CO2 that occurs in the reservoir. For a given oil and reservoir temperature, the CO2–oil minimum miscibility pressure (MMP) is strongly and adversely affected by the presence of CH4, the concentration of which varies with time and operational conditions, such as injection pressure, flooding pattern, and injection scheme (i.e., continuous CO2 injection or WAG). To capture the full range of potential variation in the MMP caused by the presence of CH4, a series of laboratory experiments were conducted to determine CO2–oil MMP with different mole percentages of CH4 in the CO2. All of the experiments were performed at reservoir temperature (108?°F) using the VIT (vanishing interfacial tension) method. Results showed that MMP increases from 1403 to 4085?psi as the mole percentage of CH4 in the CO2 increases from 0% to 100%. To assess the impact of this variation in MMP on the oil recovery performance in the field, a history-matched, compositional reservoir simulation model was used to predict the oil production performance for a WAG flood using CO2 that contained a range of CH4 concentrations. The reservoir simulations examined the effects of permeability heterogeneity, fluid crossflow, and phase behavior on the oil displacement performance in three-dimensional space over time. Simulation results indicated that CO2 floods using a limited range of CO2–CH4 mixtures could still maintain multiple-contact miscibility and result in effective EOR. In addition, the ability to reinject produced CO2–CH4 mixtures as is, without removal of the CH4, ensured that this approach to EOR would continue to be cost-effective.Jin, L., Pekot, L.J., Smith, S.A., Salako, O., Peterson, K.J., Bosshart, N.W., Hamling, J.A., Mibeck, B.A.F., Hurley, J.P., Beddoe, C.J., Gorecki, C.D., 2018. Effects of gas relative permeability hysteresis and solubility on associated CO2 storage performance. International Journal of Greenhouse Gas Control 75, 140-150. enhanced oil recovery (EOR) has been carried out in the Bell Creek oil field since 2013. Together with the encouraging oil production results, a considerable quantity of CO2 has also been trapped in the reservoir as a normal part of the EOR process, also referred to as associated storage. Because of the complex geologic conditions in the field, a series of experimental and modeling work have been conducted to better understand the CO2 EOR and associated storage performance in the reservoir. Effects of gas relative permeability hysteresis and solubility on associated CO2 storage performance are thoroughly investigated in this study.A proportion of injected CO2 remains behind through residual and solubility trapping mechanisms when CO2 flows through a reservoir during a CO2 EOR process. Over 50 core plugs were collected from the reservoir to characterize the rock properties. Mineralogical analysis and capillary pressure measurements showed that the mineral composition and pore-size distribution in the reservoir are favorable for residual trapping of CO2. The hysteresis of gas relative permeability was measured to assess the effect of residual trapping on associated CO2 storage using steady-state relative permeability tests and reservoir simulation. The reservoir oil was characterized based on pressure–volume–temperature experiments and Peng–Robinson equation of state modeling, which showed that CO2 solubility in oil is much greater (≥5 times) than in water. Results indicated that depleted oil reservoirs have great potential to store a huge quantity of CO2 associated with EOR operations, as residual oil saturation is 0.3 or greater in most conventional oil reservoirs after water flooding.Jin, X., Shi, Z., Rigo, M., Franceschi, M., Preto, N., 2018. Carbonate platform crisis in the Carnian (Late Triassic) of Hanwang (Sichuan Basin, South China): Insights from conodonts and stable isotope data. Journal of Asian Earth Sciences 164, 104-124. the Carnian, the Hanwang area in the northwestern Sichuan Basin (South China) was characterized by shallow water carbonate sedimentation that underwent an abrupt demise associated to a sudden input of terrigenous sediments. This major facies change was considered to be the expression of the onset of the Carnian Humid Episode, a most remarkable environmental crisis in Late Triassic that is well recognized in northwestern Tethys margins and coincides with a major global perturbation of the carbon stable isotope record. However, the lack of detailed biostratigraphic constraints have so far prevented a precise dating of the carbonate platform demise in western Sichuan Basin.In this work, the Qingyan Gou (HWQ) section, cropping out in Hanwang, was investigated for its facies and microfacies, carbonate carbon and oxygen isotopes on brachiopods, microbial grains and bulk matrix. Facies analysis shows a marine transgression from inner ramp oolitic shoal to middle ramp siliceous sponge mound, then overlain by shale and calcareous siltstone with interbedded silty mudstones. Refined biostratigraphic data from HWQ and Guanyin Ya (HWG) sections imply that the demise of sponge mounds occur in the late Tuvalian or later.A negative carbon isotope perturbation was found in the bulk matrix immediately below the sponge mounds demise, but it was not found on the isotope record from brachiopods. This suggests that the negative shift in the bulk carbonate was probably related to diagenesis. Given the late Tuvalian (last substage of Carnian) age attributed to the demise of the sponge mounds and the absence of a carbon isotopic excursion, we infer that the carbonate platform crisis and strong terrigenous input in Hanwang cannot be related to the onset of the Carnian Humid Episode. These the demise of the carbonate platform and the facies deepening trend could be rather due to the interplay between accelerating subsidence rates, environmental chants and enhanced siliciclastic input related to the formation of a foreland basin during Indosinian orogenesis.Jin, Y., Han, D.Y., Cao, Z.B., Qiao, H.Y., Shi, W.W., Xin, Y.Y., 2018. Extraction and spectroscopy analysis of basic nitrogen and phenolic compounds of the shale oil of Baoming oil shale, China Oil Shale 35, 183–194. (DMF) was used as a refining solvent to separate the diesel distillate of shale oil of Baoming oil shale, Xinjiang Province, China. The basic nitrogen and phenolic compounds of the shale oil diesel distillate were first concentrated in the extract oil, then enriched using column chromatography (CC) and thereafter analyzed by Fourier transform infrared spectrometry (FT-IR) and gas chromatography-mass spectrometry (GC-MS). The relative content of the basic nitrogen compounds were increased from 12.09% in the extract oil to 69.50% in the concentrated product by employing the CC method. The relative content of phenolic com?pounds was increased from 21.55% in the extract oil to 87.57% in the con?centrated product. The results showed that the basic nitrogen and phenolic compounds in the diesel distillate of Baoming shale oil could be concentrated and separated gradiently by solvent refining and column chromatography. Sixty basic nitrogen compounds were identified in the concentrated product. Thirty-three phenolic compounds, mainly phenol, alkyl phenol, thymol, naphthol and alkyl naphthol, were identified in the final enriched product. The alkyl phenols consisted mainly of C1–C3 phenolic compounds.Johansson, L., Zahirovic, S., Müller, R.D., 2018. The interplay between the eruption and weathering of Large Igneous Provinces and the deep-time carbon cycle. Geophysical Research Letters 45, 5380-5389.: Although many sources of atmospheric CO2 have been estimated, the major sinks are poorly understood in a deep‐time context. Here we combine plate reconstructions, the eruption ages and outlines of Large Igneous Provinces (LIPs), and the atmospheric CO2 proxy record to investigate how their eruptions and weathering within the equatorial humid zone impacted global atmospheric CO2 since 400 Ma. Wavelet analysis reveals significant correlations between the eruption of the Emeishan LIP (259 Ma), the Siberian Traps (251 Ma), the Central Atlantic Magmatic Province (201 Ma), the second pulse of the North Atlantic Igneous Province (55 Ma), the High Arctic LIP (130 Ma), and the Deccan Traps (65 Ma) and perturbations in atmospheric CO2. Our analysis also reveals a clear relationship between the weathering of the Central Atlantic Magmatic Province (~200–100 Ma), the Deccan Traps (50–35 Ma), and the Afar Arabian LIP (30–0 Ma) and a significant atmospheric CO2 drawdown. Our results illustrate the significant role of subaerial LIP emplacement and weathering in modulating atmospheric CO2 and Earth's surface environments. Plain Language Summary: Carbon dioxide in the atmosphere plays a significant role in regulating Earth's climate. There are many processes, which over geologic timescales add to or sequester CO2 from the atmosphere, and in turn alter Earth's climate. Here we investigate processes involved in the eruption and weathering of Large Igneous Provinces (LIPs), massive nonexplosive volcanic eruption of basaltic lava and rock. During eruptions, LIPs contribute significant amounts of CO2 to the atmosphere in very short periods of geologic time, and subsequently, when basalt is exposed to physical and chemical weathering, the process will draw CO2 from the atmosphere. We consider both eruptions, and the subsequent latitudinal positions of the LIPs in the context of their weathering, which is most severe at low latitudes due to high tropical precipitation rates. We find that periods of elevated atmospheric CO2 were related to the eruption of the Emeishan LIP and Siberian Traps (260—240 Ma), the Central Atlantic Magmatic Province (210—190 Ma), and the North Atlantic Igneous Province, High Arctic LIP, and the Deccan Traps (90—60 Ma) and those of lowered CO2 to be related to weathering of the Central Atlantic Magmatic Province (~200–100 Ma), the Deccan Traps (as it drifted through low latitude regions ~50–35 Ma), and the Afar Arabian LIP (30–0 Ma). Our analysis reveals the significant role LIPs have played in modulating Earth's climate. John, G.F., Han, Y., Clement, T.P., 2018. Fate of hopane biomarkers during in-situ burning of crude oil — A laboratory-scale study. Marine Pollution Bulletin 133, 756-761. burning (ISB) is a remediation strategy that is used for managing oil spills. ISB generates heavy residues that can submerge and negatively impact benthic environments. To track the fate of toxic contaminants in ISB residues, a conservative hopane biomarker, such as C30-αβ hopane, is often used. Furthermore, diagnostic ratios of various hopanes are used for source oil identification. Use of these biomarkers assume that during ISB the quantity of C30-αβ hopane will be conserved, and the diagnostic ratios of various hopanes will be stable. The objective of this study is to test the validity of these two assumptions. We conducted laboratory-scale ISB experiments using a model oil prepared from commercial C30-αβ hopane standard, and a reference crude oil. Laboratory data collected under controlled burning conditions show that C30-αβ hopane will not be conserved; however, the diagnostic ratios of hopanes will still remain fairly stable.Johnson, K.P., Nguyen, N.-p., Sweet, A.D., Boyd, B.M., Warnow, T., Allen, J.M., 2018. Simultaneous radiation of bird and mammal lice following the K-Pg boundary. Biology Letters 14. diversification of parasite groups often occurs at the same time as the diversification of their hosts. However, most studies demonstrating this concordance only examine single host–parasite groups. Multiple diverse lineages of ectoparasitic lice occur across both birds and mammals. Here, we describe the evolutionary history of lice based on analyses of 1107 single-copy orthologous genes from sequenced genomes of 46 species of lice. We identify three major diverse groups of lice: one exclusively on mammals, one almost exclusively on birds and one on both birds and mammals. Each of these groups radiated just after the Cretaceous–Paleogene (K-Pg) boundary, the time of the mass extinction event of the dinosaurs and rapid diversification of most of the modern lineages of birds and mammals.Jones, E.D., 2018. Ancient DNA's history of the science before Jurassic Park. Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences 68–69, 1-14. history highlights the search for DNA from ancient and extinct organisms from the late 1970s to the mid 1980s, uncovering the origination and exploration of ideas that contributed to the construction of this new line of research.1 Although this is the first academic historical account of ancient DNA's disciplinary development, there are other reviews and reports that outline its history.2 Most cite a paper published in Nature in 1984, where researchers reported the discovery of DNA from a 140-year-old extinct quagga, as the beginning of ancient DNA's history. Most also cite Michael Crichton's 1990 book and Steven Spielberg's 1993 movie, Jurassic Park, as the beginning of its popularity. I argue for a different history. Drawing on archival material as well as published and unpublished documents, this paper presents a new narrative about the search for DNA from fossils.First, this article argues that ideas regarding the recovery of DNA from fossils were pursued by different people in different places, both inside and outside of the lab, at around the same time. Stories about these ideas and the individuals who championed them have been told in one way or another, but they have never been told together in a way that captures their contribution to the disciplinary development of ancient DNA research. There are six strands of inquiry in this history starting with (one) Charles Pellegrino and extending to (2) John Tkach, (three) George Poinar and Roberta Hess, (four) Michael Crichton, (five) Allan Wilson and Russell Higuchi, and (six) Svante P??bo. I argue that an array of actors from futurists and enthusiasts to scientists and the popular press contributed to ancient DNA's early history, and that what we see as science often has its beginnings with ideas and individuals that are outside the conventional confinements of the laboratory.Second, this article argues that from the beginning, particularly preceding the release of Jurassic Park, the search for DNA from fossils was closely connected to the idea of bringing back extinct organisms. Ancient DNA elicited enthusiasm and speculation across different audiences. Some imagined using DNA to study evolutionary history. Others speculated about its potential to resurrect long-lost species. These ideas were coupled but also contested. This study showcases the interplay between science, speculation, and spectacle – particularly around the idea of bringing dinosaurs back to life – as influential in ancient DNA's early history. I argue that this interplay contributed to the construction of expectations for this new line of research and played a part in its emergence, then evolution, into a discipline.Appreciation of this historical and intellectual connection between the idea of recovering ancient genetic material and resurrecting extinct organisms, especially the ways in which individuals associated or dissociated from the coupling of these ideas, is essential for understanding the whole of ancient DNA's disciplinary development within the broader backdrop of evolutionary biology. Crucially, this account and analysis of ancient DNA research contributes to wider historical, sociological, and philosophical conversations about disciplinary development in terms of the features that help to form new disciplines, as well as those that sustain them over time.Jones, M.M., Sageman, B.B., Meyers, S.R., 2018. Turonian sea level and paleoclimatic events in astronomically tuned records from the tropical North Atlantic and Western Interior Seaway. Paleoceanography and Paleoclimatology 33, 470-492. hiatuses punctuate the Middle to Upper Turonian Substages of the Western Interior Basin (WIB, USA), interrupting an otherwise highly resolved and relatively conformable Upper Cretaceous stratigraphic record. To determine the duration and possible causes of these hiatuses, while simultaneously reconstructing Turonian carbon cycling, we develop a new astronomically tuned carbon isotope (δ13C) chemostratigraphy from time?equivalent organic carbon?rich shales of the tropical North Atlantic (Demerara Rise?Ocean Drilling Program Leg 207). A Gaussian kernel smoothing and cross-correlation technique is also introduced to quantitatively correlate the astronomically tuned Demerara Rise δ13C chemostratigraphy to coeval records globally. This analysis reveals a general consistency among ages for Turonian δ13C excursions from astronomical and radioisotopic timescales. It also indicates that a positive oxygen isotope excursion at Demerara Rise, previously interpreted to signify cooling, is synchronous (~±200?ka) with the Ogbourne Hardground in the English Chalk, the Bass River?Magothy sequence boundary, and an expansive mid?Turonian hiatus in the WIB. However, the event is not concurrent with maximum regression in the WIB. Trends in δ13C, and additional geochemical data from Demerara Rise (weight percent total organic carbon, weight percent carbonate, and C/N), are consistent with oceanic upwelling conditions modulated by monsoonal winds, which drove significant organic carbon burial instep with several prominent positive δ13C excursions (e.g., Hitchwood #2?3). Moreover, δ13C and weight percent total organic carbon preserve strong obliquity power (~1?Ma). This suggests that higher cross-equatorial insolation gradients resulting from changes in Earth's axial tilt intensified monsoonal winds, strongly influencing tropical Atlantic organic carbon burial and Turonian carbon cycling dynamics following Ocean Anoxic Event 2.Kaiser, J., Moros, M., Tomczak, M., Dellwig, O., Schulz-Bull, D., Arz, H.W., 2018. The invasive diatom Pseudosolenia calcar-avis and specific C25 isoprenoid lipids as a sedimentary time marker in the Black Sea. Geology 46, 507-510. time markers based on the recent history of anthropogenic radionuclides or pollutants are extremely valuable in synchronizing and calibrating proxy-based records with instrumental data and observations. However, such time markers are rare for the early 20th century, and any additional time marker for this time period would be valuable for studying the early anthropogenic impact on Earth. The invasive marine phytoplanktonic diatom Pseudosolenia calcar-avis (Schultze) (Sundstr?m, 1986) was first observed in the Black Sea in A.D. 1924–1926 after its introduction by ships’ ballast water. In a sediment core dated by an event stratigraphy approach, the first appearance of both remnant frustules and two C25 highly branched isoprenoid (HBI) alkenes produced by P. calcar-avis has been estimated at A.D. 1925 ± 8 yr. Therefore, the appearance of P. calcar-avis frustules and C25 HBIs can serve as a time marker (or isochrone) for A.D. 1925 in Black Sea sediments. The pronounced increase in C25 HBI contents toward the present day reflects, very likely, the increase in the biomass of P. calcar-avis, which became a mass phytoplankton species in the modern Black Sea. Using anthropogenic radionuclides and pollutants, together with first appearances of invasive species, as sedimentary time markers for the last century is a promising stratigraphic approach that could be applied in other suitable environments where historical data on invasive species are available.Kalambet, Y., Kozmin, Y., Samokhin, A., 2018. Comparison of integration rules in the case of very narrow chromatographic peaks. Chemometrics and Intelligent Laboratory Systems 179, 22-30. of peak integration is revised for very narrow peaks. It is shown, that Trapezoidal rule area is efficient estimate of full peak area with extraordinary low error. Simpson's rule is less efficient in full area integration. Theoretical conclusions are illustrated by digital simulation and processing of experimental data. It was shown that for Gaussian peak Trapezoidal rule requires 0.62 points per standard deviation (2.5 points per peak width at baseline) to achieve integration error of only 0.1%, while Simpson's rule requires 1.8 times higher data rates. Asymmetric peaks require higher data rates as well. Reasons of poor behavior of Simpson's rule are discussed; averaged Simpson's rules are constructed, these rules coincide with those based on Euler-Maclaurin formula. Euler-Maclaurin rules can reduce error in the case of partial peak integration. Higher peak moments (average retention time, dispersion, skewness, etc.) also exhibit extraordinary low errors and can potentially be used for evaluation of peak shape.Kamari, A., Li, L., Sheng, J.J., 2018. Effects of rock pore sizes on the PVT properties of oil and gas-condensates in shale and tight reservoirs. Petroleum 4, 148-157. make up a large proportion of the rocks with extremely low permeability representing many challenges which can be complex in many cases. A careful study of rock and fluid properties (i.e. PVT of shales) of such resources is needed for long-term success, determining reservoirs quality, and increased recovery factor in unique unconventional plays. In this communication, a comprehensive thermodynamic modelling is undertaken in which capillary pressure is coupled with the phase equilibrium equations. To this end, the data associated with both shale oil and gas-condensates of Eagle Ford shale reservoir located in South Texas, U.S., is used. Different properties, including bubble and dew point pressures, capillary pressure, interfacial tension, liquid and gas densities, and liquid and gas viscosities, are predicted observing the effects of rock pore sizes by the thermodynamic modelling performed in this study. The results demonstrate that the thermodynamic model developed in this study is capable of simulating the PVT properties of oil and gas-condensates in shale and tight reservoirs. For a binary mixture 25:75 C1/C6, the bubble point pressure at different reservoir temperature is increased by increasing the pore sizes from 10 to 50?nm. Furthermore, an increase in pore sizes from 10 to 50?nm can increase the dew point pressure for a studied binary mixture 75:25 C1/C6.Kamennaya, N.A., Zemla, M., Mahoney, L., Chen, L., Holman, E., Holman, H.-Y., Auer, M., Ajo-Franklin, C.M., Jansson, C., 2018. High pCO2-induced exopolysaccharide-rich ballasted aggregates of planktonic cyanobacteria could explain Paleoproterozoic carbon burial. Nature Communications 9, 2116. contribution of planktonic cyanobacteria to burial of organic carbon in deep-sea sediments before the emergence of eukaryotic predators ~1.5?Ga has been considered negligible owing to the slow sinking speed of their small cells. However, global, highly positive excursion in carbon isotope values of inorganic carbonates ~2.22–2.06?Ga implies massive organic matter burial that had to be linked to oceanic cyanobacteria. Here to elucidate that link, we experiment with unicellular planktonic cyanobacteria acclimated to high partial CO2 pressure (pCO2) representative of the early Paleoproterozoic. We find that high pCO2 boosts generation of acidic extracellular polysaccharides (EPS) that adsorb Ca and Mg cations, support mineralization, and aggregate cells to form ballasted particles. The down flux of such self-assembled cyanobacterial aggregates would decouple the oxygenic photosynthesis from oxidative respiration at the ocean scale, drive export of organic matter from surface to deep ocean and sustain oxygenation of the planetary surface.Kaplan, H.H., Milliken, R.E., Alexander, C.M.O.D., 2018. New constraints on the abundance and composition of organic matter on Ceres. Geophysical Research Letters 45, 5274-5282.: Near‐infrared reflectance spectra from the Dawn mission at Ceres were recently found to exhibit a 3.4 μm absorption indicative of the presence of aliphatic organic compounds. Constraints on abundance and composition of these organics are necessary to inform discussions of their origin. We model reflectance spectra of organic‐bearing regions on Ceres using laboratory spectra of insoluble organics of known composition extracted from terrestrial sedimentary rocks (i.e., kerogens) and carbonaceous chondrite meteorites (i.e., insoluble organic matter, IOM). The 3.4 μm aliphatic organic absorptions observed in Dawn near‐infrared data are stronger than those observed in lab spectra of carbonaceous chondrites, and modeling requires 45% to 65% spectral fraction of IOM to fit spectra from Ceres. The spectral fraction of kerogen necessary to fit the same Ceres spectra ranges from 5% to 15% depending on the hydrogen to carbon ratio of the kerogen. Any proposed mechanism of organic delivery or formation on Ceres should explain the presence of highly concentrated IOM or why the composition is distinct from meteorite‐derived IOM if lower organic abundances are considered more plausible. Plain Language Summary: Organics were recently detected on the dwarf planet Ceres with infrared spectroscopy. The origin of these organics is, as yet, unknown. Using laboratory spectra of terrestrial and extraterrestrial (meteorite‐derived) organic materials with known composition, we reanalyze the Ceres spectra to constrain composition and abundance of those organics. Such constraints could help us discern whether these organics formed on Ceres or were delivered by an impactor. Katz, B.J., Arango, I., 2018. Organic porosity: A geochemist's view of the current state of understanding. Organic Geochemistry 123, 1-16. the increasing interest in unconventional resource plays, there have been important changes in the way how reservoirs and their attributes are assessed and characterized. Of particular relevance to the development of unconventional plays has been the focus on the assessment of organic porosity. A review of the available literature reveals contradictions with respect to where organic porosity develops (kerogen, bitumen, or pyrobitumen), when it develops with respect to hydrocarbon generation and cracking (within the oil window or beyond), its mode of formation (inherited or authigenic), the influence of organic carbon content, and the importance of organic porosity with respect to hydrocarbon storage and production. Many of these apparent contradictions appear to result from the nature of the data sets upon which the studies are based. Organic pore size generally limits the role that organic porosity plays in liquid-rich plays.From the available literature, it has become clear that there are number of issues that need to be clarified when addressing organic porosity. One such issue is terminology. There appears to be confusion in the usage of the terms kerogen, bitumen, and pyrobitumen. This confusion exists in the literature and reports prepared by various service providers for those engaged in the exploration and exploitation of unconventional resources. Another issue is the observed differences in the morphology of the organic pores (e.g., spongy, isolated bubbles, or fractures). Differences in pore morphology indicate multiple mechanisms for formation and/or growth of organic pores, suggesting more complexity to organic porosity development than often implied. For example, the spongy appearance of organic pores in some systems could reflect the amorphous character of some oil-prone kerogen, whereas the bubble pore character could be the result of degassing during the transition from the oil window into the gas window or an artifact of decompression and degassing as bitumen solidifies during core retrieval. Similarly, fractures could be a result of the conversion of oil to gas and the inability of the gas to escape or could be desiccation cracks, possibly formed after sample retrieval. Organic pores, if present in situ, increase space for hydrocarbon storage and increase surface area resulting in higher absorption capacity. However, the connectivity of these pores may be somewhat limited and may be dependent on the nature of the organic network, thus limiting their impact on permeability.A challenge when studying organic porosity is its observed variability within an individual reservoir. Very different spatial distribution of pores can occur between adjacent organic particles (e.g., macerals, solid bitumen) as well as within individual “macerals”. It has been suggested that this could be, in part, a result of organic–inorganic interactions although alternative interpretations have also been proposed. Further complicating the scientific understanding of organic porosity is the possibility that the act of studying the samples containing these pores may result in alteration of the rocks and the pores themselves. Therefore, observed organic pores may not be reflective of native conditions.The lack of a clear understanding of organic porosity development in unconventional mudstone reservoirs is by no means a surprise. Porosity and its development in conventional reservoirs have been studied since Sorby began the examination of sandstone thin sections in 1850 and is still under examination, while organic porosity has been studied for less than a decade. The focus of this study is to provide a review of porosity associated with the organic fraction, which may, in some shale-reservoirs, play a key role in hydrocarbon storage, migration, and production.Kazmierczak, P.R., Paredes, M.L.L., Lima, E.R.A., Coutinho, J.A.P., 2018. A comparative analysis of thermophysical properties correlations for n-paraffins to be used in wax precipitation modeling. Fluid Phase Equilibria 472, 172-184. performance of a thermodynamic wax precipitation model strongly depends upon the n-paraffin thermophysical properties used. In order to estimate them, several correlations have been proposed, and their values have a great impact on both calculated wax disappearance temperature (WDT) and amount of wax precipitated at each temperature (WPC). The main goal of this work is to evaluate the correlations available for the relevant thermophysical properties aiming at achieving a reliable wax precipitation modeling. The methodology used involves the direct comparison of the correlations with the values of pure n-paraffin properties, and indirect evaluation by their use in the estimation of wax disappearance temperatures, the amount of wax precipitated at each temperature, and DSC experimental curves. This study contemplates two thermodynamic approaches for paraffin precipitation: the solid solution (SS), which considers the formation of one solid solution; and the multisolid phase model (MS), that assumes that each solid phase consists of a pure component.Kent, D.V., Olsen, P.E., Rasmussen, C., Lepre, C., Mundil, R., Irmis, R.B., Gehrels, G.E., Giesler, D., Geissman, J.W., Parker, W.G., 2018. Empirical evidence for stability of the 405-kiloyear Jupiter–Venus eccentricity cycle over hundreds of millions of years. Proceedings of the National Academy of Sciences 115, 6153-6158;.: Rhythmic climate cycles of various assumed frequencies recorded in sedimentary archives are increasingly used to construct a continuous geologic timescale. However, the age range of valid theoretical orbital solutions is limited to only the past 50 million years. New U–Pb zircon dates from the Chinle Formation tied using magnetostratigraphy to the Newark–Hartford astrochronostratigraphic polarity timescale provide empirical confirmation that the unimodal 405-kiloyear orbital eccentricity cycle reliably paces Earth’s climate back to at least 215 million years ago, well back in the Late Triassic Period.Abstract: The Newark–Hartford astrochronostratigraphic polarity timescale (APTS) was developed using a theoretically constant 405-kiloyear eccentricity cycle linked to gravitational interactions with Jupiter–Venus as a tuning target and provides a major timing calibration for about 30 million years of Late Triassic and earliest Jurassic time. While the 405-ky cycle is both unimodal and the most metronomic of the major orbital cycles thought to pace Earth’s climate in numerical solutions, there has been little empirical confirmation of that behavior, especially back before the limits of orbital solutions at about 50 million years before present. Moreover, the APTS is anchored only at its younger end by U–Pb zircon dates at 201.6 million years before present and could even be missing a number of 405-ky cycles. To test the validity of the dangling APTS and orbital periodicities, we recovered a diagnostic magnetic polarity sequence in the volcaniclastic-bearing Chinle Formation in a scientific drill core from Petrified Forest National Park (Arizona) that provides an unambiguous correlation to the APTS. New high precision U–Pb detrital zircon dates from the core are indistinguishable from ages predicted by the APTS back to 215 million years before present. The agreement shows that the APTS is continuous and supports a stable 405-kiloyear cycle well beyond theoretical solutions. The validated Newark–Hartford APTS can be used as a robust framework to help differentiate provinciality from global temporal patterns in the ecological rise of early dinosaurs in the Late Triassic, amongst other problems.Khorshidian, H., James, L.A., Butt, S.D., 2018. Pore-level investigation of the influence of wettability and production rate on the recovery of waterflood residual oil with a gas assisted gravity drainage process. Energy & Fuels 32, 6438-6451. assisted gravity drainage (GAGD) is an oil recovery mechanism that can be implemented after waterflood to enhance the recovery of oil. The performance of postwaterflood GAGD is affected by a variety of parameters that determine the balance between capillary, gravitational, and viscous forces. In this research, the influence of the wettability, heterogeneities, and production rate on the recovery of oil have been studied at the pore level to recognize phenomena affecting mechanisms of oil recovery visualizing interfaces in a newly designed micromodel that contains a coarse pore network covered by fine capillaries. Experimental results show that regions with high oil saturation (oil-bank) were formed ahead of the gas front in both oil-wet and water-wet micromodels when the production rate was low. Under oil-wet conditions, the size of the oil-bank was greater, and the recovery of oil initiated prior to a gas breakthrough. Under water-wet conditions, the flow of the residual oil after a gas breakthrough was initially restricted by the presence of the residual water in small pores and fine capillaries. However, high oil recovery was finally obtained upon an effective reduction of the water saturation extending the time of the process. Under both wettability conditions, increasing the drainage rate contributed to the instability of gas fronts and early gas breakthroughs without a remarkable oil recovery. The experimental result implies that, although the oil production characteristics under oil-wet and water-wet conditions are different, both of the wettability states have potential for the implementation of postwaterflood GAGD.Khosravani Haghighi, S., Nabipour, M., 2018. Application of LSSVM algorithm as a novel tool for prediction of density of bitumen and heavy n-alkane mixture. Petroleum Science and Technology 36, 1137-1142. most of oil reservoirs in the world are heavy oil and bitumen reservoirs. Due to high viscosity and density of these types of reservoirs the production has problems so importance of enhanced oil recovery (EOR) processes for them is clear. The injection of solvents such as tetradecane is known as one of methods which improve oil recovery from bitumen reservoirs. In the present investigation, the Least squares support vector machine (LSSVM) algorithm was used to estimate density of Athabasca bitumen and heavy n-alkane mixture in term of temperature, pressure and weight percent of the solvent. The Root mean square error (RMSE), average absolute relative deviation (AARD) and the coefficient of determination (R2) for total dataset are determined 0.033466, 0.0025686 and 1 respectively. The predicted results indicate that the LSSVM algorithm has potential to be a predicting machine for the bitumen-heavy alkane mixture density prediction.Kiang, N.Y., Domagal-Goldman, S., Parenteau, M.N., Catling, D.C., Fujii, Y., Meadows, V.S., Schwieterman, E.W., Walker, S.I., 2018. Exoplanet biosignatures: At the dawn of a new era of planetary observations. Astrobiology 18, 619-629. rapid rate of discoveries of exoplanets has expanded the scope of the science possible for the remote detection of life beyond Earth. The Exoplanet Biosignatures Workshop Without Walls (EBWWW) held in 2016 engaged the international scientific community across diverse scientific disciplines, to assess the state of the science and technology in the search for life on exoplanets, and to identify paths for progress. The workshop activities resulted in five major review papers, which provide (1) an encyclopedic review of known and proposed biosignatures and models used to ascertain them (Schwieterman et al.,2018 in this issue); (2) an in-depth review of O2 as a biosignature, rigorously examining the nuances of false positives and false negatives for evidence of life (Meadows et al.,2018 in this issue); (3) a Bayesian framework to comprehensively organize current understanding to quantify confidence in biosignature assessments (Catling et al.,2018 in this issue); (4) an extension of that Bayesian framework in anticipation of increasing planetary data and novel concepts of biosignatures (Walker et al.,2018 in this issue); and (5) a review of the upcoming telescope capabilities to characterize exoplanets and their environment (Fujii et al.,2018 in this issue). Because of the immense content of these review papers, this summary provides a guide to their complementary scope and highlights salient features. Strong themes that emerged from the workshop were that biosignatures must be interpreted in the context of their environment, and that frameworks must be developed to link diverse forms of scientific understanding of that context to quantify the likelihood that a biosignature has been observed. Models are needed to explore the parameter space where measurements will be widespread but sparse in detail. Given the technological prospects for large ground-based telescopes and space-based observatories, the detection of atmospheric signatures of a few potentially habitable planets may come before 2030. Key Words: Killgrove, K., Tykot, R.H., 2018. Diet and collapse: A stable isotope study of Imperial-era Gabii (1st–3rd centuries AD). Journal of Archaeological Science: Reports 19, 1041-1049. city of Gabii arose just east of Rome around the 8th century BC. By the Imperial period, it had all but collapsed, its habitation areas either abandoned or repurposed for industrial production. Burials within the city, however, may speak to the urbanization and collapse of Gabii. Twenty-one skeletons from the Imperial era (1st–3rd centuries AD) were analyzed for stable carbon and nitrogen isotopes in an effort to understand palaeodiet. Adults' diets are relatively homogeneous, particularly in comparison with samples from nearby sites dating to the same period, and reflect consumption of terrestrial meats and C3 plants. Subadult diets do not reflect breastfeeding at the time of death. One individual with anomalous isotopes may have been an immigrant to Gabii.Kitadai, N., Maruyama, S., 2018. Origins of building blocks of life: A review. Geoscience Frontiers 9, 1117-1153. and where did life on Earth originate? To date, various environments have been proposed as plausible sites for the origin of life. However, discussions have focused on a limited stage of chemical evolution, or emergence of a specific chemical function of proto-biological systems. It remains unclear what geochemical situations could drive all the stages of chemical evolution, ranging from condensation of simple inorganic compounds to the emergence of self-sustaining systems that were evolvable into modern biological ones. In this review, we summarize reported experimental and theoretical findings for prebiotic chemistry relevant to this topic, including availability of biologically essential elements (N and P) on the Hadean Earth, abiotic synthesis of life’s building blocks (amino acids, peptides, ribose, nucleobases, fatty acids, nucleotides, and oligonucleotides), their polymerizations to bio-macromolecules (peptides and oligonucleotides), and emergence of biological functions of replication and compartmentalization. It is indicated from the overviews that completion of the chemical evolution requires at least eight reaction conditions of (1) reductive gas phase, (2) alkaline pH, (3) freezing temperature, (4) fresh water, (5) dry/dry-wet cycle, (6) coupling with high energy reactions, (7) heating-cooling cycle in water, and (8) extraterrestrial input of life’s building blocks and reactive nutrients. The necessity of these mutually exclusive conditions clearly indicates that life’s origin did not occur at a single setting; rather, it required highly diverse and dynamic environments that were connected with each other to allow intra-transportation of reaction products and reactants through fluid circulation. Future experimental research that mimics the conditions of the proposed model are expected to provide further constraints on the processes and mechanisms for the origin of life.Kleiner, M., Dong, X., Hinzke, T., Wippler, J., Thorson, E., Mayer, B., Strous, M., 2018. Metaproteomics method to determine carbon sources and assimilation pathways of species in microbial communities. Proceedings of the National Academy of Sciences 115, E5576-E5584.: To understand the roles that microorganisms play in diverse environments such as the open ocean or the human intestinal tract, we need an understanding of their metabolism and physiology. A variety of methods such as metagenomics and metaproteomics exist to assess the metabolism of environmental microorganisms based on gene content and gene expression. These methods often only provide indirect evidence for which substrates are used by a microorganism in a community. The direct protein stable isotope fingerprint (SIF) method that we developed allows linking microbial species in communities to the environmental carbon sources they consume by determining their stable carbon isotope signature. Direct protein-SIF also allows assessing which carbon fixation pathway is used by autotrophic microorganisms that directly assimilate CO2.Abstract: Measurements of stable carbon isotope ratios (δ13C) are widely used in biology to address questions regarding food sources and metabolic pathways used by organisms. The analysis of these so-called stable isotope fingerprints (SIFs) for microbes involved in biogeochemical cycling and microbiota of plants and animals has led to major discoveries in environmental microbiology. Currently, obtaining SIFs for microbial communities is challenging as the available methods either only provide low taxonomic resolution, such as the use of lipid biomarkers, or are limited in throughput, such as nanoscale secondary ion MS imaging of single cells. Here we present “direct protein-SIF” and the Calis-p software package (), which enable high-throughput measurements of accurate δ13C values for individual species within a microbial community. We benchmark the method using 20 pure culture microorganisms and show that the method reproducibly provides SIF values consistent with gold-standard bulk measurements performed with an isotope ratio mass spectrometer. Using mock community samples, we demonstrate that SIF values can also be obtained for individual species within a microbial community. Finally, a case study of an obligate bacteria–animal symbiosis shows that direct protein-SIF confirms previous physiological hypotheses and can provide unexpected insights into the symbionts’ metabolism. This confirms the usefulness of this approach to accurately determine δ13C values for different species in microbial community samples.Knockaert, J., Balasse, M., Rendu, C., Burens, A., Campmajo, P., Carozza, L., Bousquet, D., Fiorillo, D., Vigne, J.-D., 2018. Mountain adaptation of caprine herding in the eastern Pyrenees during the Bronze Age: A stable oxygen and carbon isotope analysis of teeth. Quaternary International 484, 60-74. activities in the northeastern Pyrenees increased substantially during the Bronze Age, raising the question of the modalities of occupations in zones where the snow cover limited access to grasslands for a significant part of the year. The present study explores how stable isotope analysis may characterize the adaptation of husbandry to mountain environments through herding strategies, including the vertical mobility of livestock. It also addresses the broader issue of the occupation of territories by Bronze Age communities in the Western Mediterranean area, focusing on possible links between coastal plains and mountainous areas. For this purpose, sequential stable carbon and oxygen isotope analyses were conducted on caprines' teeth from the mountain site of Llo (Pyrénées-Orientales, 1630?m asl, Middle Bronze Age) and the permanent coastal site of Portal-Vielh (Hérault, 0?m asl, Late Bronze Age). An exploratory analysis was also conducted on modern sedentary and transhumant ewes to investigate the effect of altitudinal mobility on enamel oxygen isotope values. The range of δ18O values measured in modern and archaeological caprines raised in mountain zones was lower than the one measured in the lowland caprines, while no significant difference could be observed in the range of δ13C values. Co-variations between δ13C and δ18O sequences reveal the most information. The positive correlation observed in all instances at low elevation sites was not the leading pattern at Llo, where a variety of schemes could be observed, including opposite δ13C and δ18O sequences. This opposition could not be explained by a reversal of the δ18O cycle due to vertical mobility. Other causes could involve changes in the pattern of variation of δ13C values, potentially linked to human responses to the local constraints, including vertical mobility and/or foddering. Portal-Vielh delivered a fully lowland signal. At Llo, although a full adaptation to a mountain environment seems clear, the question of the vertical mobility of δ13C livestock cannot be resolved at the moment. Most importantly, Llo was characterized by a high inter-individual variability in the co-variation of δ13C and δ18O profiles, reflecting great plasticity of the husbandry practices on the inter-annual scale. This could have been a key to the adaptation to these marginal environments. The apparent disjunction between the coastal and mountain settlements, as far as herd trajectory is concerned, must be reaffirmed by further investigations in a larger number of sites.Kobraei, M., Rabbani, A., 2018. Gas-condensate potential of the middle-Jurassic petroleum system in Abadan plain, Southwest Iran: Results of 2-D basin modeling. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 40, 1161-1174. Jurassic petroleum system has been proven as prolific oil and gas prospects in the southwestern of Iran. During this study, 2-D regional modeling was done on two selected sections (north-south and east-west); furthermore, 1-D models were reconstructed on 7 deeply drilled wells in order to evaluate petroleum generation and source rock maturity histories in the Abadan Plain area in southwest Iran. The results revealed that the Middle Jurassic Sargelu Formation with average present-time TOC and HI values of 2.65wt% and 151 mgHC/gTOC, respectively, can be classified as good to excellent type II source rock. The initial TOC and HI values regarded for modeling are 5wt% and 620 mgHC/gTOC, respectively. The geochemical maturity parameters indicate a wet gas window for the Sargelu Formation. The modeling results show that the maximum temperature and vitrinite reflectance in the Sargelu Formation has reached 150 oC and 1.3%VRo. Generation of hydrocarbon in the Sargelu commenced during the Early Cretaceous, while the main expulsion happened in the Paleogene. 2-D models show that the Jurassic source rock has already reached a high transformation ratio within the studied area and, due to lack of intense tectonic activity, the maturity is the same throughout the studied area. Oil and gas migrated mostly vertically to the overlying traps which are existed in the Jurassic and Cretaceous succession. The results predict the existence of gas-condensate in the Jurassic petroleum system of the studied area.Koeksoy, E., Halama, M., Hagemann, N., Weigold, P.R., Laufer, K., Kleindienst, S., Byrne, J.M., Sundman, A., Hanselmann, K., Halevy, I., Schoenberg, R., Konhauser, K.O., Kappler, A., 2018. A case study for late Archean and Proterozoic biogeochemical iron‐ and sulphur cycling in a modern habitat—the Arvadi Spring. Geobiology 16, 353-368. a consequence of Earth's surface oxygenation, ocean geochemistry changed from ferruginous (iron(II)‐rich) into more complex ferro‐euxinic (iron(II)‐sulphide‐rich) conditions during the Paleoproterozoic. This transition must have had profound implications for the Proterozoic microbial community that existed within the ocean water and bottom sediment; in particular, iron‐oxidizing bacteria likely had to compete with emerging sulphur‐metabolizers. However, the nature of their coexistence and interaction remains speculative. Here, we present geochemical and microbiological data from the Arvadi Spring in the eastern Swiss Alps, a modern model habitat for ferro‐euxinic transition zones in late Archean and Proterozoic oceans during high‐oxygen intervals, which enables us to reconstruct the microbial community structure in respective settings for this geological era. The spring water is oxygen‐saturated but still contains relatively elevated concentrations of dissolved iron(II) (17.2 ± 2.8 μM) and sulphide (2.5 ± 0.2 μM) with simultaneously high concentrations of sulphate (8.3 ± 0.04 mM). Solids consisting of quartz, calcite, dolomite and iron(III) oxyhydroxide minerals as well as sulphur‐containing particles, presumably elemental S0, cover the spring sediment. Cultivation‐based most probable number counts revealed microaerophilic iron(II)‐oxidizers and sulphide‐oxidizers to represent the largest fraction of iron‐ and sulphur‐metabolizers in the spring, coexisting with less abundant iron(III)‐reducers, sulphate‐reducers and phototrophic and nitrate‐reducing iron(II)‐oxidizers. 16S rRNA gene 454 pyrosequencing showed sulphide‐oxidizing Thiothrix species to be the dominating genus, supporting the results from our cultivation‐based assessment. Collectively, our results suggest that anaerobic and microaerophilic iron‐ and sulphur‐metabolizers could have coexisted in oxygenated ferro‐sulphidic transition zones of late Archean and Proterozoic oceans, where they would have sustained continuous cycling of iron and sulphur compounds. K?k, M.V., Varfolomeev, M.A., Nurgaliev, D.K., 2018. Wax appearance temperature (WAT) determinations of different origin crude oils by differential scanning calorimetry. Journal of Petroleum Science and Engineering 168, 542-545. this research, wax appearance temperatures (WAT) of eight different crude oils from south-eastern region of Turkey were determined by differential scanning calorimetry. The experiments were performed at a heating/cooling-rate of 2?°C/min from 60 to ?20?°C It was observed that the wax appearance temperature of different origin crude oils was varied between 14.2 and 37.8?°C depending on the API gravity and wax content. It was also observed that the crude oils have enthalpy of precipitation ranging from ?3.42 to +6.39?mW and melting enthalpy from – 2.5 to +7.46?mW, respectively.K?nig, S., Worrich, A., Banitz, T., Centler, F., Harms, H., K?stner, M., Miltner, A., Wick, L.Y., Thullner, M., Frank, K., 2018. Spatiotemporal disturbance characteristics determine functional stability and collapse risk of simulated microbial ecosystems. Scientific Reports 8, Article 9488. microbial ecosystems are exposed to many types of disturbances varying in their spatial and temporal characteristics. The ability to cope with these disturbances is crucial for maintaining microbial ecosystem functions, especially if disturbances recur regularly. Thus, understanding microbial ecosystem dynamics under recurrent disturbances and identifying drivers of functional stability and thresholds for functional collapse is important. Using a spatially explicit ecological model of bacterial growth, dispersal, and substrate consumption, we simulated spatially heterogeneous recurrent disturbances and investigated the dynamic response of pollutant biodegradation – exemplarily for an important ecosystem function. We found that thresholds for functional collapse are controlled by the combination of disturbance frequency and spatial configuration (spatiotemporal disturbance regime). For rare disturbances, the occurrence of functional collapse is promoted by low spatial disturbance fragmentation. For frequent disturbances, functional collapse is almost inevitable. Moreover, the relevance of bacterial growth and dispersal for functional stability also depends on the spatiotemporal disturbance regime. Under disturbance regimes with moderate severity, microbial properties can strongly affect functional stability and shift the threshold for functional collapse. Similarly, networks facilitating bacterial dispersal can delay functional collapse. Consequently, measures to enhance or sustain bacterial growth/dispersal are promising strategies to prevent functional collapses under moderate disturbance regimes.Kosakowski, P., Koltun, Y., Machowski, G., Poprawa, P., Papiernik, B., 2018. The geochemical characteristics of the Oligocene – Lower Miocene Menilite Formation in the Polish and Ukrainian Outer Carpathians: A review. Journal of Petroleum Geology 41, 319-335. principal source rocks in the Outer Carpathians are organic‐rich shales in the Oligocene to Lower Miocene Menilite Formation. The average total organic carbon (TOC) content in the Menilite Formation is 4–8 wt%; the maximum measured is 26 wt%. Organic matter (OM) is oil‐prone Type II kerogen derived mainly from algae and cyanobacteria which was deposited under euxinic conditions. The thermal maturity of the Menilite shales varies significantly within the Outer Carpathians, both vertically in relation to burial depth and laterally in different tectonic units, and increases from external to internal parts of the orogenic belt. Maturity in general ranges from immature to different phases of the “oil window” and up to the “gas window”. Kotla, S.S., Patnaik, R., Sehgal, R.K., Kharya, A., 2018. Isotopic evidence for ecological and climate change in the richly fossiliferous Plio-Pleistocene Upper Siwalik deposits exposed around Chandigarh, India. Journal of Asian Earth Sciences 163, 32-42. Plio-Pleistocene Siwalik deposits around Chandigarh, well known for their great wealth of mammalian fossils, preserve a continuous record of calcareous paleosols ranging in age from ～2.7 to ～0.6?Ma. The carbon isotope composition (δ13C relative to Vienna Peedee belemnite [VPDB]) of 140 pedogenic carbonates from Ghaggar and Nadah sections and 13 gastropod samples from Nadah section record a landscape primarily occupied by C4 grasses during this interval. However, a mixed C3–C4 vegetation between 2.15 and 1.7?Ma and a progressive increase in the percentage of C3 plants from ～1.1 to ～0.6?Ma has been recorded. Most of the pedogenic carbonate δ18O values (VPDB) in the Ghaggar River Section range between ?5.29 and ?8.93‰ indicating the dominance of monsoon climate. These δ18O values exhibit somewhat consistent trend in relation to δ13C values suggesting influence of climate on the vegetation. At two instances ～1.07 and ～0.66?Ma, there is significant depletion in carbonate δ18O and δ13C values, suggesting monsoon intensification and a synchronous development of C3 vegetation. Pedogenic carbonate and gastropod δ18O values (VPDB) in the Nadah paleoswamp, also exhibit consistent trends in relation to δ13C values, indicating steady relationship between short-term climatic fluctuations in terms of warm-humid and cool-dry conditions and the abundance of C3/C4 biomass on the landscape nearly 1.8?Ma ago. The vegetation change on the Siwalik landscape during Early and Middle Pleistocene appears to have been influenced mainly by the regional tectonics, sedimentation patterns and monsoonal rains rather than global climate changes.Kraková, L., ?oltys, K., Otlewska, A., Pietrzak, K., Purkrtová, S., Savická, D., Pu?kárová, A., Bu?ková, M., Szemes, T., Budi?, J., Demnerová, K., Gutarowska, B., Pangallo, D., 2018. Comparison of methods for identification of microbial communities in book collections: Culture-dependent (sequencing and MALDI-TOF MS) and culture-independent (Illumina MiSeq). International Biodeterioration & Biodegradation 131, 51-59. identification strategies employing new methodologies, namely, culture-dependent (using matrix-assisted laser desorption/ionization – time-of-flight mass spectrometry, MALDI-TOF MS) and culture-independent (using high-throughput sequencing on Illumina MiSeq platform) approaches, were applied for the first time to analysis of the deteriorating microflora of book samples. We compared two different identification techniques coupled to microbial cultivation: DNA sequencing and MALDI-TOF MS. The two identification systems produced almost the same results. DNA sequencing was able to better identify all the recovered isolates, while MALDI-TOF MS failed to properly recognize Streptomyces ambofaciens and Lysinibacillus fusiformis, the latter method permitting identification at least at genus level. In addition, the isolates Myxotrichum deflexum and Oidiodendron cerealis were not identified by the MALDI-TOF MS approach. This incongruence was caused by the absence of different kinds of microorganisms in the MALDI BioTyper reference database. The Illumina high-throughput sequencing coupled to non-invasive sampling allowed the identification of a complex bacterial and fungal community. The study presents the satisfactory performance of two novel alternative identification methods (MALDI-TOF MS and Illumina MiSeq) for the investigation of microflora colonizing archival items.Kramer, E.D., Rowan, M., 2018. Revisiting the dark matter - comet shower connection. arXiv:1610.04239v2 [astro-ph.EP] revisit the question of whether the observed periodicity of comet impacts on Earth is consistent with Solar oscillation about the Galactic midplane and spiral arm crossings, here in the context of dissipative dark matter models. Consider whether a hypothetical thin dark disk, a signature of these models, is necessary to give the right periodicity, and whether such a dark disk is allowed given kinematic and other observational constraints on the Galaxy's gravitational potential, taking into account recent updates of these limits based on the vertical epicyclic oscillations of the tracer populations. Our analysis contains updated parameters for the Galactic disk, a self-consistent gravitational potential under the Poisson-Jeans equations, and includes prior probabilities from local stellar kinematics and the distribution of Milky Way interstellar gas. Moreover, our analysis also includes radial oscillations and Galactic spiral arm crossings. We find a dark disk explanation for the comet periodicity to be 10 times more likely than a constant average rate model. Moreover, we find that spiral arm crossing is necessary to correctly predict the date of the Chicxulub crater dated to 66 My ago. Kraus, E.A., Beeler, S.R., Mors, R.A., Floyd, J.G., GeoBiology 2016, Stamps, B.W., Nunn, H.S., Stevenson, B.S., Johnson, H.A., Shapiro, R.S., Loyd, S.J., Spear, J.R., Corsetti, F.A., 2018. Microscale biosignatures and abiotic mineral authigenesis in Little Hot Creek, California. Frontiers in Microbiology 9, 997. doi: 910.3389/fmicb.2018.00997. spring environments can create physical and chemical gradients favorable for unique microbial life. They can also include authigenic mineral precipitates that may preserve signs of biological activity on Earth and possibly other planets. The abiogenic or biogenic origins of such precipitates can be difficult to discern, therefore a better understanding of mineral formation processes is critical for the accurate interpretation of biosignatures from hot springs. Little Hot Creek (LHC) is a hot spring complex located in the Long Valley Caldera, California, that contains mineral precipitates composed of a carbonate base (largely submerged) topped by amorphous silica (largely emergent). The precipitates occur in close association with microbial mats and biofilms. Geological, geochemical, and microbiological data are consistent with mineral formation via degassing and evaporation rather than direct microbial involvement. However, the microfabric of the silica portion is stromatolitic in nature (i.e., wavy and finely laminated), suggesting that abiogenic mineralization has the potential to preserve textural biosignatures. Although geochemical and petrographic evidence suggests the calcite base was precipitated via abiogenic processes, endolithic microbial communities modified the structure of the calcite crystals, producing a textural biosignature. Our results reveal that even when mineral precipitation is largely abiogenic, the potential to preserve biosignatures in hot spring settings is high. The features found in the LHC structures may provide insight into the biogenicity of ancient Earth and extraterrestrial rocks.Krickov, I.V., Lim, A.G., Manasypov, R.M., Loiko, S.V., Shirokova, L.S., Kirpotin, S.N., Karlsson, J., Pokrovsky, O.S., 2018. Riverine particulate C and N generated at the permafrost thaw front: case study of western Siberian rivers across a 1700-km latitudinal transect. Biogeosciences Discussions 2018, 1-32. contrast to numerous studies on the dynamics of dissolved (<?0.45??m) elements in permafrost-affected high latitude rivers, very little is known of the behavior of river suspended (>?0.45??m) matter (RSM) in these regions. In order to test the effect of climate, permafrost and physio-geographical landscape parameters (bogs, forest and lake coverage of the watershed) on RSM and particulate C, N and P concentration in river water, we sampled 33 small and medium size rivers (10–100?000?km2 watershed) along a 1700?km N–S transect including both permafrost-affected and permafrost-free zones of Western Siberian Lowland (WSL). The concentration of C and N in RSM decreased with the increase in river watershed size, illustrating (i) the importance of organic debris in small rivers which drain peatlands and (ii) the role of mineral matter from bank abrasion in larger rivers. The presence of lakes in the watershed increased C and N but decreased P concentrations in RSM. The C?:?N ratio in the RSM reflected the source from deep rather than surface soil horizon, similar to that of other Arctic rivers. This suggests the export of peat and mineral particles through suprapermafrost flow occurring at the base of the active layer. There was a maximum of particulate C and N concentration at the beginning of permafrost appearance (a sporadic and discontinuous zone, 62–64°?N). This presumably reflected the organic matter mobilization from newly thawed organic horizons in soils at the active latitudinal thawing front. The results suggest that a northward shift of permafrost boundaries and an increase in active layer thickness may increase particulate C and N export by WSL rivers to the Arctic Ocean by a factor of 2, while P export may remain unchanged. In contrast, within a long-term climate warming scenario, the disappearance of permafrost in the north, the drainage of lakes and transformation of bogs to forest may decrease C and N concentration in RSM by 2 to 3 times.Kuippers, G., Boothman, C., Bagshaw, H., Ward, M., Beard, R., Bryan, N., Lloyd, J.R., 2018. The biogeochemical fate of nickel during microbial ISA degradation; implications for nuclear waste disposal. Scientific Reports 8, Article 8753. level radioactive waste (ILW) generally contains a heterogeneous range of organic and inorganic materials, of which some are encapsulated in cement. Of particular concern are cellulosic waste items, which will chemically degrade under the conditions predicted during waste disposal, forming significant quantities of isosaccharinic acid (ISA), a strongly chelating ligand. ISA therefore has the potential to increase the mobility of a wide range of radionuclides via complex formation, including Ni-63 and Ni-59. Although ISA is known to be metabolized by anaerobic microorganisms, the biodegradation of metal-ISA complexes remains unexplored. This study investigates the fate of a Ni-ISA complex in Fe(III)-reducing enrichment cultures at neutral pH, representative of a microbial community in the subsurface. After initial sorption of Ni onto Fe(III)oxyhydroxides, microbial ISA biodegradation resulted in >90% removal of the remaining Ni from solution when present at 0.1?mM, whereas higher concentrations of Ni proved toxic. The microbial consortium associated with ISA degradation was dominated by close relatives to Clostridia and Geobacter species. Nickel was preferentially immobilized with trace amounts of biogenic amorphous iron sulfides. This study highlights the potential for microbial activity to help remove chelating agents and radionuclides from the groundwater in the subsurface geosphere surrounding a geodisposal facility.Kularatne, K., Sissmann, O., Kohler, E., Chardin, M., Noirez, S., Martinez, I., 2018. Simultaneous ex-situ CO2 mineral sequestration and hydrogen production from olivine-bearing mine tailings. Applied Geochemistry 95, 195-205. alteration batch experiments were conducted on olivine bearing mine tailings in order to investigate two potential valorization methods: the ex-situ CO2 sequestration and hydrogen production. The originality of this work lies in the simultaneous investigation of these two processes. We reacted powdered mine tailings with CO2-saturated water at three different sets of P/T conditions, 473?K/15?MPa, 523?K/30?MPa and 573?K/30?MPa. After 25 days of reaction, CO2 was sequestered in the form of Fe-bearing magnesite, (Mg,Fe)CO3 in all the experiments. Maximum carbonation yield was achieved at 523?K and 30?MPa, which was 53.8?wt.% of product, equivalent to the trapping of 320.5?g of CO2 per kg of mine tailings. Hydrogen gas was produced via the oxidation of Fe2+ in olivine. The highest quantity of hydrogen (H2) was produced at 573?K/30?MPa which was 0.57?g of H2 per kg of mine tailings. It suggests that the temperatures between 523?K and 540?K?at pCO2?=?30?MPa are favorable for simultaneous ex-situ CO2 mineral sequestration and hydrogen production from New Caledonian mine tailings.The combined method of ex-situ CO2 storage and hydrogen production proposed by this study offsets 90% of New Caledonia's annual CO2 emissions while compensating ～10% of New Caledonia's annual energy demand. More globally, it has implications for cost effective disposal of industrial CO2 emissions and production of hydrogen gas (clean energy) at a large scale; those two processes could be combined using the residual heat provided by a third one such as the high temperature smelting of ore.Kumar, K., 2018. Introducing an integral optimised warping (IOW) approach for achieving swift alignment of drifted chromatographic peaks: an optimisation of the correlation optimised warping (COW) technique. Analytical Methods 10, 2764-2774. drift in the position of chromatographic peaks is an unavoidable problem that needs to be taken care of before subjecting them to any data analysis work packages. The correction is essential because each of these data analysis work packages compares the chromatograms at each retention time point. Thus, it is important that a peak if present in all chromatograms must appear at the same retention time point. Correlation optimised warping (COW) has found its place in various data analysis work packages as a pre-processing technique to correct the drift in the chromatographic peak position. However, it has a disadvantage that computationally it is demanding, laborious and time consuming; as a result it becomes the bottleneck for any work package. The present work addresses this issue by introducing a novel approach baptised as integral optimised warping (IOW) that makes the correction of the drift in the peak position a simple and swift process. IOW achieves this by reducing the ambiguity in selecting the reference chromatogram and synthesising the reference chromatogram mathematically using a Gaussian function. COW optimises the combination of segment length (m) and slack (t) parameters by maximizing the Pearson correlation ([small rho]) coefficient between the reference and the warped chromatogram. COW calculates the [small rho] values for every possible combination of m and t making it a computationally challenging task. The IOW algorithm reduces the computational time that is required to optimise m and t by a significant amount by introducing mathematical criteria that allow evaluation of the integral overlap between the reference and the warped chromatogram only if the overlap occurs in a specified region around the reference peak. The IOW algorithm also reduces the computational time significantly by allowing simultaneous alignment of a specific peak in all the chromatograms. The utility of IOW is successfully demonstrated using simulated as well as real life chromatograms.Kumar, N., Mandal, A., 2018. Surfactant stabilized oil-in-water nanoemulsion: Stability, interfacial tension, and rheology study for enhanced oil recovery application. Energy & Fuels 32, 6452-6466. are kinetically stable biphasic dispersion of two immiscible liquids typically stabilized by an emulsifier with droplet sizes in the range of 10–200 nm. Present work deals with the formulation and characterization of stable oil-in-water nanoemulsions using nonionic surfactant (Tween 40) and light mineral oil for their application in enhanced oil recovery. The stability study of the nanoemulsions formed by high energy and low energy method was accomplished by bottle testing method. The emulsions were characterized in terms of droplet size, morphology and inner structure, surface charge, interfacial tension, and rheology. Droplet sizes of 18–31 nm obtained by dynamic light scattering analysis and surface charge values above ?35 mV obtained by ζ potential measurement prove the higher kinetic stability of the formed emulsions. Cryo-TEM micrographs reveal the surface morphology and inner structure of nanoemulsions. A miscibility test was performed to determine the dissolving ability of the nanoemulsions with crude oil. Measurement of interfacial tension (IFT) by pendant drop method shows a considerable reduction in IFT values with the increase of surfactant concentration and temperature, which is highly desirable for recovering trapped oil from the fine pores of the reservoirs. The viscosity of the nanoemulsions remains stable at a wide temperature (30–70 °C) range, denoting its thermal stability. The viscoelastic property of prepared nanoemulsions shows the increase of storage modulus (G′) and loss modulus (G″) with the increase in surfactant concentration and angular frequency (rad/s). Specific frequency (SF), the crossover point of G′ and G″, indicates the transition between elastic and viscous phases of nanoemulsions. A stable value of loss modulus after SF denotes better flowability of the emulsion. To test the efficiency of nanoemulsion in enhanced oil recovery, flooding experiment was performed by injection of a small pore volume of emulsion slug in a sand pack system, and an additional recovery of 28.94% was obtained after conventional water flooding.Kumari, W.G.P., Ranjith, P.G., Perera, M.S.A., Li, X., Li, L.H., Chen, B.K., Isaka, B.L.A., De Silva, V.R.S., 2018. Hydraulic fracturing under high temperature and pressure conditions with micro CT applications: Geothermal energy from hot dry rocks. Fuel 230, 138-154. fracturing has been widely employed to enhance the permeability of tight geological formations including deep geothermal reservoirs. However, due to the complex in-situ stresses, high-temperature conditions and heterogeneity of the formations, hydraulic fracturing under deep geothermal conditions is poorly understood to date. The aim of the current study is, therefore, to investigate the effect of reservoir depth, temperature, and sample heterogeneity during hydraulic fracturing and the influences of rock micro-structure on fracture propagation. A series of hydraulic fracturing experiments was conducted on two Australian granite types under a wide range of confining pressures from 0 to 60?MPa and temperatures from room temperature to 300?°C simulating different geothermal environments. The corresponding micro-structural effects on the rock matrix were investigated employing high-resolution CT imaging using the IMBL facility of the Australian Synchrotron. According to the results, the breakdown pressure of reservoir rock linearly increases with reservoir depth (confining pressure). However, with increasing temperature breakdown pressure linearly decreases. This corresponds to the linear reduction of tensile strength measured by high-temperature Brazilian tensile tests. In addition, CT images showed that the injection of cold water into hot rock can result in a porous zone with porosity ranging from 2 to 3% close to the wellbore due to thermally-induced inter- and intra-crystalline cracks. In this condition, fluid leak-off is high and the measured fracture aperture of the main hydraulic fracture is relatively small. Further, fracture propagation paths and apertures are mainly controlled by the stress state and the heterogeneity of the rock matrix. It was found that fractures tend to propagate along preferential paths, mainly along grain boundaries and in large quartz and biotite minerals (grain size?&gt;?0.3?mm) and minerals with pre-existing micro-cracks.Lai, H., Fang, H., Huang, L., He, G., Reible, D., 2018. A review on sediment bioflocculation: Dynamics, influencing factors and modeling. Science of The Total Environment 642, 1184-1200. in a water column provides excellent substratum for microorganism colonization, and biological processes would alter the physical and chemical of sediment, resulting in substantial changes in sediment dynamics. The flocculation of sediment with biological processes are defined as sediment bioflocculation, which has been ubiquitously observed across aquatic ecosystems, activated sludge plants and bioflocculant applications, as a result of various processes involving particle aggregation and breakage under the complex effects of microorganisms and their metabolic products (e.g., extracellular polymeric substances EPS). EPS are complex high-molecular-weight mixtures of polymers, which are the primary components that hold microbial aggregates together by acting as a biological glue. Several mechanistic aggregation theories such as the alginate theory, adsorption bridging theory, divalent cation bridging theory, and Derjaguin–Landau–Verwey–Overbeek (DLVO) theory, and a number of influencing factors (e.g., sediment properties, microbial activity, EPS quantities and components, and external environment conditions) have been proposed to elucidate the role of microorganisms and EPS in sediment aggregation, promoting the investigation of the sediment bioflocculation evolution and kinetics models. However, due to the complex interrelationships of multiple physical, chemical, and biological processes and the incomprehensive knowledge of microorganisms and EPS, considerable research should be further conducted to fully understand their precise roles in the sediment bioflocculation process. In this study, a review of dynamic characterizations, mechanism, influencing factors and models of sediment bioflocculation are given to obtain a more comprehensive understanding of sediment bioflocculation dynamics.Landry, Z.C., Vergin, K., Mannenbach, C., Block, S., Yang, Q., Blainey, P., Carlson, C., Giovannoni, S., 2018. Optofluidic single-cell genome amplification of sub-micron bacteria in the ocean subsurface. Frontiers in Microbiology 9, 152. doi: 110.3389/fmicb.2018.01152. single-cell genome amplification was used to obtain genome sequences from sub-micron cells collected from the euphotic and mesopelagic zones of the northwestern Sargasso Sea. Plankton cells were visually selected and manually sorted with an optical trap, yielding twenty partial genome sequences representing seven bacterial phyla. Two organisms, E01-9C-26 (Gammaproteobacteria), represented by four single cell genomes, and Opi.OSU.00C, an uncharacterized Verrucomicrobia, were the first of their types retrieved by single cell genome sequencing and were studied in detail. Metagenomic data showed that E01-9C-26 is found throughout the dark ocean, while Opi.OSU.00C was observed to bloom transiently in the nutrient-depleted euphotic zone of the late spring and early summer. The E01-9C-26 genomes had an estimated size of 4.76-5.05 Mbps, and contained ‘O’ and ‘W’-type monooxygenase genes related to methane and ammonium monooxygenases that were previously reported from ocean metagenomes. Metabolic reconstruction indicated E01-9C-26 are likely versatile methylotrophs capable of scavenging C1 compounds, methylated compounds, reduced sulfur compounds, and a wide range of amines, including D-amino acids. The genome sequences identified E01-9C-26 as a source of ‘O’ and ‘W’-type monooxygenase genes related to methane and ammonium monooxygenases that were previously reported from ocean metagenomes, but are of unknown function. In contrast, Opi.OSU.00C genomes encode genes for catabolizing carbohydrate compounds normally associated with eukaryotic phytoplankton. This exploration of optofluidics showed that it was effective for retrieving diverse single-cell bacterioplankton genomes and has potential advantages in microbiology applications that require working with small sample volumes or targeting cells by their morphology.Lapidus, A.L., Kerimov, V.Y., Mustaev, R.N., Movsumzade, E.M., Zakharchenko, M.V., 2018. Caucasus Maykopian kerogenous shale sequences: Generative potential. Oil Shale 35, 113–127. generative potential of kerogenous shale sequences in the Caucasus Maykopian series, the southern part of European Russia, is evaluated. The Khadum and Batalpashin sediments in the Eastern and Central Fore-Caucasus include three types of kerogen: I, II and III. The Khadum sediments are dominated by a more “noble” type II kerogen, mixed humic-sapropelic organic matter (OM). The Maykopian series may be attributed to the category of “rich” and “very rich” (“outstanding”) oil source rocks. The maturity extent of the subject sediments within the region varies between the grades of protokatagenesis (maximum pyrolysis tem?perature (Tmax) = 390 °С) and MC4 (Tmax = 471 °С). Based on the pyrolytic studies, the Khadum and Batalpashin sediments are distinct from other pelitic rocks in rather high generative potential values. The average value of the total generative potential (S1 + S2) in the studied samples from the Khadum and Batalpashin Formations is 4.83 mg HC/g rock. The quantitative estimate of the hydrocarbon generative potential of the Khadum and Batalpashin sediments in this region was conducted for the first time. The total initial generative hydrocarbon potential of the sediments is 133.4 BT, being 92.7 BT for the Khadum Formation, and 40.7 BT for the Batalpashin Formation.Latour, P., Hong, W.-L., Sauer, S., Sen, A., Gilhooly III, W.P., Lepland, A., Fouskas, F., 2018. Dynamic interactions between iron and sulfur cycles from Arctic methane seeps Biogeosciences Discussions 2018, 1-48. iron is an important micro-nutrient for marine phytoplankton and therefore critical to global biogeochemical cycles. Anoxic marine sediment is a significant source of Fe(II) to the ocean. Here, we investigate how the fluxes of Fe(II), both towards the sedimentary oxic layer and across the sediment-water interface, are impacted by the high concentration and flux of porewater sulfide in cold seep environments. We present new porewater data from four recently documented cold seeps around Svalbard as well as from continental shelves and fjords in northern Norway. We quantitatively investigated porewater data first by calculating the Fe(II) fluxes towards oxidized surface sediments and bottom water and, second, applied a transport-reaction model to estimate the mass balance of several key chemical species. Sedimentary sulfur speciation data from two of the sites were used to constrain Fe(II) consumption in the shallow sediments. We showed that the iron reduction zone is usually confined to the top 10?cm of the sediments from our studied sites due to high sulfate turnover and therefore high sulfide flux. Such a thin iron reduction zone allows proportionally more Fe(II) to reach the bottom water. Rapid precipitation of pyrite occurs at the base of the iron reduction zone, where the downward diffusing Fe(II) meets upward migrating hydrogen sulfide. Dissolved H2 released during pyrite formation stimulates a small but significant rate of sulfate reduction in the same horizon, which results in faster production of hydrogen sulfide and a positive feedback for iron reduction in the shallow sediment. Deeper in the sediment, where sulfate is actively consumed due to anaerobic methane oxidation, no apparent formation of pyrite is observed from the available measurements and our modeling results. This is mostly due to the relatively low availability of Fe(II) as a result of slower turnover of the less active iron mineral phases. Such an observation may contradict the use of pyrite abundance to deduce the sulfate-methane-transition-zone in past sedimentary records. A series of model sensitivity tests were performed to systematically investigate how the Fe(II) dynamics is impacted by higher deposition rate of iron (oxyhydr)oxides minerals on the seafloor and intensifying methane supply. We showed that the increases in iron reduction rate, pyrite formation rate, and Fe(II) flux are expected with higher seafloor iron (oxyhydr)oxides deposition initially. However, complicated feedbacks between Fe(II) production and sulfate reduction pose negative feedbacks to pyrite formation in the sediments. With a larger supply of methane, Fe(II) flux towards the oxic surface sediments is initially intensified by the higher production of hydrogen sulfide until such an interplay is too fast that essentially all reactive iron minerals settled on the seafloor dissolve immediately and dissolved iron is fixed through pyrite precipitation. Such an interplay between Fe(II) and sulfide determines the distribution of animals with chemoautotrophic symbionts which rely on sulfide as their energy source.Le Masle, A., Santin, S., Marlot, L., Chahen, L., Charon, N., 2018. Centrifugal partition chromatography a first dimension for biomass fast pyrolysis oil analysis. Analytica Chimica Acta 1029, 116-124. fast pyrolysis oils contain molecules having a large variety of chemical functions and a wide range of molecular weights (from several tens to several thousand grams per mole). The good knowledge of their complex composition is essential for optimizing the conversion of bio-oils to biofuels, thereby requiring powerful separation techniques. In this work, we investigate the interest of centrifugal partition chromatography (CPC) as a first dimension for the analysis of a bio-oil. A CPC method is proposed to separate oxygen containing compounds according to their partition coefficients in the solvent system. This approach is a powerful and easy-to-use technique that enables fractionation of a bio-oil at a semi-preparative scale, without any sample loss related to adsorption on the stationary phase. Collected fractions are then injected in liquid chromatography as a second dimension of separation. Contour plot representations of the CPC?×?LC separation are established to discuss the potential of this approach. These representations can be used as a veritable fingerprint in the comparison of different samples or samples at different steps of a conversion process but also as a powerful tool to identify new compounds and describe the entire composition of the bio-oil.Le Moine Bauer, S., Stensland, A., Daae, F.L., Sandaa, R.-A., Thorseth, I.H., Steen, I.H., Dahle, H., 2018. Water masses and depth structure prokaryotic and T4-like viral communities around hydrothermal systems of the Nordic Seas. Frontiers in Microbiology 9, 1002. doi: 1010.3389/fmicb.2018.01002. oceanographic features of the Nordic Seas, situated between Iceland and Svalbard, have been extensively studied over the last decades. As well, the Nordic Seas hydrothermal systems situated on the Arctic Mid-Ocean Ridge System have received an increasing interest. However, there is very little knowledge on the microbial communities inhabiting the water column of the Nordic Seas, and nothing is known about the influence of the different water masses and hydrothermal plumes on the microbial community structures. In this study, we aimed at characterizing the impact of hydrothermal plumes on prokaryotic and T4-like viral communities around the island of Jan Mayen. To this end, we used 16S rRNA-gene and g23-gene profiling as well as flow cytometry counts to examine prokaryotic and viral communities in 27 samples obtained from different water masses in this area. While Thaumarchaeota and Marine group II Archaea dominated the waters deeper than 500 m, members of Flavobacteria generally dominated the shallower waters. Furthermore, extensive chemical and physical characteristics of all samples were obtained, including temperature measurements and concentrations of major ions and gases. The effect of these physiochemical variables on the communities was measured by using constrained and unconstrained multivariate analyzes, Mantel tests, network analyzes, phylogenetic analyzes, taxonomic analyzes and temperature-salinity (Θ-S) plots. Our results suggest that hydrothermal activity has little effect on pelagic microbial communities in hydrothermal plumes of the Nordic Seas. However, we provide evidences that observed differences in prokaryotic community structure can largely be attributed to which water mass each sample was taken from. In contrast, depth was the major factor structuring the T4-like viral communities. Our results also show that it is crucial to include water masses when studying the influence of hydrothermal plumes on microbial communities, as it could prevent to falsely associate a change in community structure with the presence of a plume.Lécuyer, C., 2018. Learning from past climatic changes. Science 360, 1400-1401. the course of the past 540 million years, five catastrophic mass extinction events occurred as a result of global climate changes. Those periods of large-magnitude warming or cooling resulted from catastrophic events such as asteroid impacts, paroxysmal volcanic activity, or peculiar geographic distributions of continents (1). The last of these mass extinction events occurred 66 million years ago at the Cretaceous/Paleogene (K/Pg) boundary, which is well known for the vanishing of ammonoids and nonavian dinosaurs (see the figure). On page 1467 of this issue, MacLeod et al. (2) provide evidence that the temperature of surface marine waters off the coast of Tunisia rose by 5°C in the 100,000 years after the K/Pg boundary.Lee, A.K., Banta, A.B., Wei, J.H., Kiemle, D.J., Feng, J., Giner, J.-L., Welander, P.V., 2018. C-4 sterol demethylation enzymes distinguish bacterial and eukaryotic sterol synthesis. Proceedings of the National Academy of Sciences 115, 5884-5889.: Sterols are essential eukaryotic lipids that can be preserved as steroids in sedimentary rocks for billions of years. Because eukaryotes are the predominant modern day producers of these lipids, fossilized sterols are used as geological biomarkers for the presence of specific eukaryotes in ancient environments. Sterol lipids are also produced by a few bacteria, but the biosynthesis and function of sterols in bacteria are not as well-understood. In this study, we used a combination of bioinformatics and lipid analyses to identify bacterial sterol synthesis proteins. Our results indicate that bacteria have evolved distinct aspects of the sterol synthesis pathway independent of eukaryotes and show that exploring sterol physiology in bacteria can provide insight into this geologically relevant pathway.Abstract: Sterols are essential eukaryotic lipids that are required for a variety of physiological roles. The diagenetic products of sterol lipids, sterane hydrocarbons, are preserved in ancient sedimentary rocks and are utilized as geological biomarkers, indicating the presence of both eukaryotes and oxic environments throughout Earth’s history. However, a few bacterial species are also known to produce sterols, bringing into question the significance of bacterial sterol synthesis for our interpretation of sterane biomarkers. Recent studies suggest that bacterial sterol synthesis may be distinct from what is observed in eukaryotes. In particular, phylogenomic analyses of sterol-producing bacteria have failed to identify homologs of several key eukaryotic sterol synthesis enzymes, most notably those required for demethylation at the C-4 position. In this study, we identified two genes of previously unknown function in the aerobic methanotrophic γ-Proteobacterium Methylococcus capsulatus that encode sterol demethylase proteins (Sdm). We show that a Rieske-type oxygenase (SdmA) and an NAD(P)-dependent reductase (SdmB) are responsible for converting 4,4-dimethylsterols to 4α-methylsterols. Identification of intermediate products synthesized during heterologous expression of SdmA-SdmB along with 13C-labeling studies support a sterol C-4 demethylation mechanism distinct from that of eukaryotes. SdmA-SdmB homologs were identified in several other sterol-producing bacterial genomes but not in any eukaryotic genomes, indicating that these proteins are unrelated to the eukaryotic C-4 sterol demethylase enzymes. These findings reveal a separate pathway for sterol synthesis exclusive to bacteria and show that demethylation of sterols evolved at least twice—once in bacteria and once in eukaryotes.Lee, K.J., Finsterle, S., Moridis, G.J., 2018. Analyzing the impact of reaction models on the production of hydrocarbons from thermally upgraded oil shales. Journal of Petroleum Science and Engineering 168, 448-464. parameters significantly affect oil production from shales by means of heating and in-situ upgrading. In this study, we perform numerical simulations of two chemical reaction models, which are mainly used in the research of kerogen pyrolysis and subsequent hydrocarbon decomposition in organic-rich porous media. They are the Braun and Burnham model and Wellington model. In these forward numerical simulations, we present the influence of the two reaction models on hydrocarbon production. The Braun and Burnham reaction model shows more vigorous kerogen and subsequent decomposition reactions and more hydrocarbon production than the Wellington model. A local sensitivity analysis identifies the reaction parameters with the highest influence on productivity, and the most sensitive outputs. A data-worth analysis identifies the most valuable observation data to be measured for the best prediction of total hydrocarbon production. We find that the most valuable observation data is the cumulative production of heavy oil in the Braun and Burnham model and of light oil in the Wellington model, respectively. Once we determine the maximum allowable prediction uncertainty and the expected measurement uncertainty, the observation data to be measured for the minimization of prediction uncertainty can be obtained.Lei, L., Seol, Y., Jarvis, K., 2018. Pore-scale visualization of methane hydrate-bearing sediments with micro-CT. Geophysical Research Letters 45, 5417-5426.: X‐ray computed tomography (CT) has become a critical technique in the study of porous media. It has attracted growing attention for analyzing hydrate‐bearing sediment, but this has been done using surrogates (Xe/Kr) only due to difficulties in distinguishing methane hydrate from water. This study presents the successful imaging of methane hydrate coexisting with pore liquid, gas, and sediments. We used potassium iodide (KI) solutions and in‐line propagation‐based phase‐contrast CT analysis of X‐ray attenuation and diffraction to distinguish the four materials. Thus, consideration for CT‐related X‐ray physics was necessary to optimize KI concentrations, improve material separation with X‐ray propagation, and properly interpret artifacts within the images. The images clearly show methane hydrate in the pore space of sand (~250 μm) coexisting with KI solution and gas. Following this, X‐ray CT can now be used to visualize pore habits of natural methane hydrate in sediment cores. Plain Language Summary: Methane hydrate has great potential as an energy resource. Thus, the behavior of methane hydrate in reservoirs is the current focus of research for gas production and environmental impacts. It is critical to know how hydrate is distributed in sediment pores and how it interacts with sediments in order to understand the potentially dynamic physical and chemical properties of hydrate‐bearing sediments. This study develops an X‐ray computed tomography technique to gain 3‐D insight into sediment pores with resolution down to micron level, while maintaining high pressure and low temperature during the scan to keep methane hydrate stable. This technique takes advantages of both the attenuation and interference of X‐ray waves. Attenuation characteristics of materials of interest are manipulated with enhancing agents to achieve optimum contrasts. X‐ray wave interference is utilized to enhance edge detection between different materials. Our results establish the ability of the proposed techniques to discern methane hydrate from its hosting environment. The proper interpretation of results relies on the fundamental understanding of X‐ray physics so that artifacts induced by X‐ray wave interference can be discerned from real features of interest on material surfaces. The technique can be utilized for various aspects of geomaterial characterization. Lei, R., Xiong, Y., Li, Y., Zhang, L., 2018. Main factors influencing the formation of thermogenic solid bitumen. Organic Geochemistry 121, 155-160. mature solid bitumen, a residue of oil cracking, is widespread in the lower Paleozoic paleo-oil reservoirs of southern China. Solid bitumen is not a simple, pure component, but rather a compositionally and structurally variable mixture of materials. This study investigated the formation of thermogenic solid bitumen and the effects of oil composition and reservoir environment. A series of seven gold-tube pyrolysis experiments were conducted: three used the main fraction groups (i.e., saturated, aromatic, and resin?+?asphaltene fractions) of crude oil to evaluate the effect of oil composition on the formation of solid bitumen during cracking; the other four tested the effects of water and pressure in reservoirs by simulating the cracking of crude oil under different reservoir conditions. Quantitative analyses of pyrolytic products (including methane, C2–C5 gaseous hydrocarbons, C6–C13 light hydrocarbons, C13+ heavy hydrocarbons, and solid bitumen) indicated that thermogenic solid bitumen formed at different stages of oil cracking, and its formation was clearly affected by oil composition. In contrast, water and pressure in the reservoir had little effect on the formation of solid bitumen.Leshuk, T., Peru, K.M., de Oliveira Livera, D., Tripp, A., Bardo, P., Headley, J.V., Gu, F., 2018. Petroleomic analysis of the treatment of naphthenic organics in oil sands process-affected water with buoyant photocatalysts. Water Research 141, 297-306. persistence of toxicity associated with the soluble naphthenic organic compounds (NOCs) of oil sands process-affected water (OSPW) implies that a treatment solution may be necessary to enable safe return of this water to the environment. Due to recent advances in high-resolution mass spectrometry (HRMS), the majority of the toxicity of OSPW is currently understood to derive from a subset of toxic classes, comprising only a minority of the total NOCs. Herein, oxidative treatment of OSPW with buoyant photocatalysts was evaluated under a petroleomics paradigm: chemical changes across acid-, base- and neutral-extractable organic fractions were tracked throughout the treatment with both positive and negative ion mode electrospray ionization (ESI) Orbitrap MS. Elimination of detected OS+ and NO+ classes of concern in the earliest stages of the treatment, along with preferential degradation of high carbon-numbered O2? acids, suggest that photocatalysis may detoxify OSPW with higher efficiency than previously thought. Application of petroleomic level analysis offers unprecedented insights into the treatment of petroleum impacted water, allowing reaction trends to be followed across multiple fractions and thousands of compounds simultaneously.Lestander, T.A., Sandstr?m, L., Wiinikka, H., ?hrman, O.G.W., Thyrel, M., 2018. Characterization of fast pyrolysis bio-oil properties by near-infrared spectroscopic data. Journal of Analytical and Applied Pyrolysis 133, 9-15. transforms bulky and heterogeneous lignocellulosic biomass into more easily-handled oils that can be upgraded into bio-based transportation fuels. Existing systems for monitoring pyrolysis processes and characterizing their products rely on slow and time-consuming wet chemical analyses. On-line near-infrared (NIR) spectroscopy could potentially replace such analyses, providing real-time data and reducing costs. To test the usefulness of NIR methods in characterizing pyrolysis oils and processes, biomass from conifers, Salix, and reed canary grass was milled and pyrolyzed at 675, 750, and 775?°C. Two separate pyrolytic fractions (aerosol and condensed) were produced in each experiment, and NIR spectra were collected for each fraction. Multivariate modelling of the resulting data clearly showed that the samples’ NIR spectra could be used to accurately predict important properties of the pyrolysis oils such as their energy values, main organic element (C, H and O) contents, and water content. The spectra also contained predictive information on the samples’ origins, fraction, and temperature treatment, demonstrating the potential of on-line NIR techniques for monitoring pyrolytic production processes and characterizing important properties of pyrolytic oils from lignocellulosic biomass.Leuchtle, B., Epping, L., Xie, W., Eiden, S.J., Koch, W., Diarra, D., Lucka, K., Zimmermann, M., Blank, L.M., 2018. Defined inoculum for the investigation of microbial contaminations of liquid fuels. International Biodeterioration & Biodegradation 132, 84-93. contamination of hydrocarbons, especially fuels, has been intensively investigated, as the contamination leads to quality losses of the fuel or damage and even destruction of storage equipment. Researchers use different microbes for these investigations. Alternative inocula include pure cultures, low diversity mixed cultures or samples from (contaminated) storage tanks. In contrast to chemical investigations, no standards exist regarding the composition and use of the organisms; hence, the results may differ widely. Here, a defined mixture for the investigation of microbial contamination of stored fuels, especially middle distillates under standardized conditions, is presented. The organisms represent genera and species commonly found in fuel storage systems. The mixture includes 27 individual species, consisting of bacteria, yeast, and molds. The microbes use heating oil as well as biodiesel as sole carbon source and produce acids and surfactants during growth. The defined mixture is diverse enough to cover all aspects of fuel contamination but defined enough for easy handling during experiments including analytics. The defined microbe mix could contribute to greater reproducibility of experiments, resulting in faster development of technical solutions to minimize or avoid microbial contamination and its negative results during fuel storage.Lewis, A., Prince, R.C., 2018. Integrating dispersants in oil spill response in Arctic and other icy environments. Environmental Science & Technology 52, 6098-6112. oil exploration and marine navigation may well extend into the Arctic Ocean, and government agencies and responders need to plan for accidental oil spills. We argue that dispersants should play an important role in these plans, since they have substantial logistical benefits, work effectively under Arctic conditions, and stimulate the rapid biodegradation of spilled oil. They also minimize the risk of surface slicks to birds and mammals, the stranding of oil on fragile shorelines and minimize the need for large work crews to be exposed to Arctic conditions.Li, C., Chen, P., Kang, S., Yan, F., Tripathee, L., Wu, G., Qu, B., Sillanp??, M., Yang, D., Dittmar, T., Stubbins, A., Raymond Peter, A., 2018. Fossil fuel combustion emission from South Asia influences precipitation dissolved organic carbon reaching the remote Tibetan Plateau: Isotopic and molecular evidence. Journal of Geophysical Research: Atmospheres 123, 6248-6258. dissolved organic carbon in precipitation (water‐soluble organic carbon, WSOC) can provide a carbon subsidy to receiving ecosystems. The concentrations, isotopic signatures (δ13C/Δ14C), and molecular signatures (transform ion cyclotron mass spectrometry) of WSOC being delivered to Nam Co—a remote site on the inland Tibetan Plateau (TP)—were compared to those of WSOC in the snowpack, and in wet deposition from urban cities fringing the TP. The average WSOC concentration at Nam Co (1.0 ± 0.9 mg C L?1) was lower than for the large cities (1.6 to 2.3 mg C L?1) but higher than in the snowpack samples (0.26 ± 0.09 mg C L?1). Based upon radiocarbon data, it is estimated that 15 ± 6% of Nam Co WSOC was fossil derived, increasing to 20 ± 8% for snowpack WSOC, 29 ± 4% for Lhasa WSOC, and 34 ± 8% for the three cities. Transform ion cyclotron mass spectrometry results revealed that the abundance of dissolved black carbon and sulfur‐containing molecules of WSOC increased in the order Nam Co < snow pack < urban. The enrichment in 14C and depletion in dissolved black carbon and sulfurous organic molecules of Nam Co WSOC was suggestive of low, but still detectable inputs of fossil‐derived organics to WSOC on the remote TP. Backward air mass trajectories for the precipitation events at Nam Co suggested that the fossil fuel contributions to WSOC in Nam Co region originated mainly from South Asia. This study provides novel radiocarbon age, chemistry, and source evidence that anthropogenic WSOC is delivered to the remote TP, one of the most remote regions on Earth. Li, C., Ostadhassan, M., Gentzis, T., Kong, L., Carvajal-Ortiz, H., Bubach, B., 2018. Nanomechanical characterization of organic matter in the Bakken Formation by microscopy-based method. Marine and Petroleum Geology 96, 128-138. shales are highly heterogeneous due to the presence of a variety of constituent components. Among them, organic matter is poorly known in terms of mechanical properties due to the lack of high-resolution analytical equipment to isolate organic matter in-situ for mechanical testing. In this study, we proposed a new method to link morphology and geochemical properties of organic matter to its mechanical characteristics at the nanoscale. Kerogen type and thermal maturity, along with mineralogy were evaluated by Rock- Eval 6 pyrolysis/Total Organic Carbon (TOC) analysis and X-ray Diffraction (XRD) analysis. Then, the atomic force microscopy PeakForce Quantitative Nano-mechanical Mapping (AFM PeakForce QNM) mode was employed and coupled with optical and electron microscopy, to first visualize and then quantify the elastic properties of organic components in three different samples from the Bakken Formation. Hebamorphinite matrix bituminite and solid bitumen were identified as the main organic constituent, along with oil-prone marine kerogen type II (alginite and acritarch) and also a bacterial-derived granular micrinite-like maceral. Based on Tmax and vitrinite Ro values (or VRo-Eq from Bitumen Ro), thermal maturity of the samples ranged from immature to mature (past peak oil window). The average value of Young's modulus for organic matter was measured in the range of 2.91–11.77?GPa. It was also found that organic matter becomes stiffer with increased thermal maturity. This study exhibits a great potential, as a novel method, for in-situ analysis of mechanical properties of organic matter in shale reservoirs at a fine scale.Li, J., Ma, W., Wang, Y., Wang, D., Xie, Z., Li, Z., Ma, C., 2018. Modeling of the whole hydrocarbon-generating process of sapropelic source rock. Petroleum Exploration and Development 45, 461-471. on experimental data from hydrocarbon generation with a semi-open system, hydrocarbon generation kinetics modeling in gold tube of closed system, high temperature pyrolysis chromatography mass spectrometry experiment with open system and geological data, the characteristics of whole hydrocarbon-generating process, hydrocarbon expulsion efficiency and retained hydrocarbon quantity, origins of natural gas generated in high-over mature stage and cracking temperature of methane homologs were investigated in this study. The sapropelic source rock has a hydrocarbon expulsion efficiency of 30%?60% and 60%?80% in the major oil generation window (with Ro of 0.8%?1.3%) and high maturity stage (with Ro of 1.3%?2.0%) respectively; and the contribution ratio of kerogen degradation gas to oil cracking gas in total generated gas in high maturity stage is about 1:4. The degradation gas of kerogen accounts for 20%, the retained liquid hydrocarbon cracking gas accounts for 13.5%, and the amount of out-reservoir oil cracking gas (including aggregation type and dispersed oil cracking gas) accounts for 66.5%. The lower limit of gas cracking is determined preliminarily. Based on the new understandings, a model of the whole hydrocarbon-generating process of source rock is built.Li, J., Wang, Q., Liu, Y., Wang, M., Tan, Y., 2018. Long branched-chain amphiphilic copolymers: Synthesis, properties, and application in heavy oil recovery. Energy & Fuels 32, 7002-7010. series of water-soluble long branched-chain amphiphilic copolymers, AAGASs, were synthesized and applied in the enhanced oil recovery of heavy oil. Hydrophobically associating water-soluble copolymers (AAGs) with an epoxy group were first synthesized by free-radical copolymerization of acrylamide (AM) and sodium 2-acrylamido-2-methylpropanesulfonic acid with glycidyl methacrylate. An amino-terminated amphiphilic copolymer (AS-N) was also prepared with AM and sodium 4-styrenesulfonate via chain transfer polymerization. AAGASs were then obtained by the chain-extending reaction between the epoxy groups of the AAG and amino group of the AS-N. Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance spectroscopy, static light scattering, and thermogravimetric analysis measurements were performed to determine the polymer structures and properties. Shear viscosity, surface tension, and interfacial tension were also investigated to understand the oil displacement mechanism of AAGAS solutions. The results showed that AAGASs have a unique associative property in solution and possess good surface and interfacial activities, allowing AAGAS solutions to both thicken water and convert highly viscous heavy oil into low-viscosity oil-in-water emulsions. Measurement of the apparent viscosities showed that AAGAS-3 achieves optimal performance with a degree of viscosity reduction of heavy oil up to 96.8% at 1000 mg/L. Therefore, our work showed a two-pronged approach for enhancing the recovery of heavy oil, namely, using a polymer incorporating water-thickening properties with heavy oil viscosity-reducing ability.Li, J., Yu, H., Wu, X., Shen, L., Liu, Y., Qiu, G., Zeng, W., Yu, R., 2018. Novel hyper antimony-oxidizing bacteria isolated from contaminated mine soils in China. Geomicrobiology Journal 35, 713-720. (Sb)-oxidizing bacteria play an important role in environmental Sb bioremediation because of their ability to convert the more toxic Sb(III) to the less toxic Sb(V). So far, the information about the Sb(III)-oxidizing bacteria species is still limited. In this study, three highly Sb(III)-resistant bacterial strains were isolated from contaminated mine soils after aerobic enrichment culturing with Sb(III) (1 mM). The morphological, biochemical, and 16S rRNA gene sequencing analysis suggested that the three novel bacterial isolates fell within Cupriavidus, Moraxella, and Bacillus, respectively. Among the strains, Moraxella sp. S2 isolated from soils with the highest Sb content exhibited the highest minimum inhibitory concentration for Sb(III) but the lowest Sb(III) oxidation efficiency, which could not completely oxidize 50 ?M Sb(III) in 15?days. Cupriavidus sp. S1 was able to oxidize 50 μM Sb(III) completely in 12?days, but could not oxidize 100 μM Sb(III) even with extended time of incubation, while Bacillus sp. S3 with the lowest resistance to Sb(III) could aerobically oxidize 100 ?M Sb(III) within 2?days, showing high Sb(III) oxidation efficiency. Our research demonstrated that indigenous microorganisms associated with Sb mine soils were capable of Sb oxidation, and the novel bacteria isolated could represent good candidates for Sb remediation in heavily polluted sites.Li, K., Rimmer, S.M., Liu, Q., 2018. Geochemical and petrographic analysis of graphitized coals from Central Hunan, China. International Journal of Coal Geology 195, 267-279. graphite can form from coal naturally as a result of igneous intrusion, but the mechanism of alteration from anthracite to graphite remains elusive. The occurrence of microcrystalline graphite in altered coal seams is not common globally; however, several microcrystalline graphite occurrences that are associated with igneous intrusions are currently being mined commercially in China. In this study, petrographic, geochemical, and X-ray diffraction analyses of a series of Carboniferous coals with different levels of graphitization were used to study transformations in coal structure and chemical composition evolution during natural graphitization.The graphitized coals were collected from mines located at varying distances from a large (~130?km2 in extent) Indosinian-period granite intrusion; the coals in this region have been highly altered by this intrusion. Mean random reflectance of the samples increases from 4.36% to 8.23% approaching the intrusion, but decreases to 4.58% in the most graphitized samples. Vitrinite and inertinite become difficult to distinguish under white light with increased coal rank, and newly formed components including pyrolytic carbon, needle graphite, and flake graphite are seen in the most graphitized samples. The pyrolytic carbon accumulated from a vapor phase that was likely generated during intrusion. The needle and flake graphite occur as fracture and void fills and probably represent graphitization of a mobile phase that migrated through the coal. Timing of generation and the source of the mobile phase is unclear, but predates graphitization and could have been associated with the intrusion event. Microcrystalline graphite, with a characteristic texture consisting of fine granular particles, is the dominant component in the most graphitized samples. Reflectance of microcrystalline graphite using standard coal procedures does not accurately reflect its rank. Approaching the intrusion, structural parameters show a progressive change, especially in highly graphitized coals. Samples closest to the intrusion have transformed into graphite (as confirmed by X-ray diffraction and geochemical data). A plot of volatile matter (VM) versus Rr suggests that the maturation pathway for graphitized coals differs from that of coals that have undergone normal burial maturation. Elemental changes in graphitized coals also differ from coals that have been intruded by smaller-scale sills and dikes. This is probably due to the extreme level of metamorphism associated with the large-scale intrusion that graphitized these coals.Li, Q., Pang, X., Tang, L., Chen, G., Shao, X., Jia, N., 2018. Occurrence features and gas content analysis of marine and continental shales: A comparative study of Longmaxi Formation and Yanchang Formation. Journal of Natural Gas Science and Engineering 56, 504-522. study the occurrence state and content of shale gas in different depositional environments, 15 marine shale samples from Longmaxi Formation in the Sichuan Basin and 15 continental shale samples from Yanchang Formation in the Ordos Basin were sampled. Then a series of experiments, including X-ray diffraction analysis, TOC content analysis, Ro measurement, NMR measurements, FE-ESEM observation, low-pressure N2 adsorption, and CH4 isothermal adsorption were conducted. In general, shale gas in Yanchang formation has the characteristics of primary adsorbed gas, moderate free gas, and non-ignorable dissolved gas, whereas shale gas in Longmaxi formation has the characteristics of joint dominated free gas and adsorbed gas, as well as negligible dissolved gas. Both macroscopic accumulation pattern and microscopic occurrence model show four stages in the whole thermal evolution, that is, adsorption, pore filling, fracture filling and accumulation. By analyzing the affecting factors of shale gas adsorption, conclusions can be drawn that geological characteristics, mineral compositions, pore structure features and formation conditions have influence on adsorbed gas content to various degrees. Cause analyses reveal that differences in occurrence state and gas content between marine and continental shales are immediately affected by the differences of organic matter type, thermal maturity, brittle minerals content, carbonate content, SSA, PD, porosity, gas saturation, residual oil quantity, as well as T&P, indirectly controlled by sedimentary environment and tectonic movement.Li, Q., Yi, L., Tang, J., Guan, W., Jiang, Y., Zheng, H., Zhou, J., Wang, X., 2018. Mechanisms and influencing factors of the oil bank in fire flooding. Petroleum Exploration and Development 45, 491-498. on the systematic summary of current research on oil bank, the definition of oil bank in the process of fire flooding and its quantitative indices were proposed; and a new one-dimensional positive dry-fire flooding model considering temperature gradient was established based on the steady flow theory of gas and liquid phases. Single factor analysis and orthogonal experiments were adopted to verify the reliability and reveal the formation mechanisms and the controlling factors of the oil bank. Then the optimal conditions for the oil bank to form were discussed. The study results show the formation of the oil bank is controlled by 3 factors: (1) Oil bank would come into being within a certain temperature interval and above a critical value of temperature gradient (absolute value), with temperature too high or too low and temperature gradient absolute value lower than the critical value, the oil bank couldn't form. (2) For fire flooding process in heavy oil reservoirs, the viscosity of oil influences the width of oil bank and the speed at which oil bank forms; the lower the oil viscosity is, the wider the oil bank is and the faster the oil bank forms. (3) Oil saturation could affect the developing temperature and speed of oil bank. The favorable temperature at which oil bank develops gets lower and the accumulating speed of oil gets faster when the oil saturation is higher. By orthogonal experiments with the model, the optimal combinations of reservoir conditions for forming oil bank during fire flooding in heavy oil reservoirs can be worked out.Li, W., Mu, L., Yin, T., Zhao, L., Zhao, A., Xie, P., Li, F., Huang, L., 2018. Distribution of remaining oil based on fine 3-D geological modelling and numerical reservoir simulation: a case of the northern block in Xingshugang Oilfield, China. Journal of Petroleum Exploration and Production Technology 8, 313-322. the Xingshugang Oilfield is in the late stage of development, a conventional geological model could not meet the needs of further enhancing oil recovery, and the establishment of a fine 3-D geological model, namely the 3-D reservoir architecture model, is urgently required. The 3-D reservoir architecture model has a strong advantage in the detailed characterization of the distribution of various architectural elements and flow baffles and barriers in 3-D space. Based on the abundant data from close well spacing, in combination with the understanding of sedimentary facies and reservoir architecture, this study builds the 3-D reservoir architecture model to show the spatial distribution of different architectural elements and intercalations (mud drapes) under the control of third-, fourth- and fifth-order bounding surfaces. The study then establishes the property model under the control of sedimentary facies (architectural elements). Subsequently, based on the fine 3-D geological model, the distribution of remaining oil is obtained after the numerical reservoir simulation. The remaining oil primarily lies in the port of channel bifurcation, the parts blocked by intercalations and abandoned channels, and the edges of different facies. This observation provides a theoretical basis for further development and adjustment.Li, X., Bai, Y., Sui, H., He, L., 2018. Understanding desorption of oil fractions from mineral surfaces. Fuel 232, 257-266. of heavy hydrocarbons from mineral surfaces is highly dependent on the oil composition and their host rock surface properties. Herein, the petroleum is divided into SARA fractions (saturates, aromatics, resins, asphaltenes) to investigate their desorption behaviors on different types of mineral surfaces (silica (SiO2), kaolinite (Al2Si2O5(OH)4) and calcium carbonate (CaCO3)). The Quartz Crystal Microbalance with Dissipation (QCM-D) tests show that the saturates and aromatics could desorb from the mineral surfaces spontaneously even in water, while no desorption was observed for the asphaltenes and resins. Although the above desorption could be enhanced by alkaline or surfactant solutions, great difference still appears to different oil fractions. Oil characterization shows that the heavy fractions (i.e., asphaltenes, resins) possess richer acid groups than those of light fractions, allowing the stronger affinity of heavy fractions to the mineral surfaces through polar and chemical interactions. Additionally, the heavy fractions dominate in determining the desorption properties of bitumen (the mixed fractions), and lead to more significant wettability alteration to the mineral surfaces. Furthermore, the oil fractions desorption is also found to be highly influenced by the mineral types. Compared with silica, kaolinite has stronger affinity to the heavy oil fractions, leading to smaller amount of desorption. While on the calcium carbonate surface, less than 11% of the coated oil fractions are observed to be desorbed. Surface characterizations summarize that, due to the difference in mineral composition, the affinity of minerals to oil components in aqueous solutions is given as: calcium carbonate (positively charged calcium ions)?>?kaolinite (containing –AlOH, –SiOH groups and heavy metal elements)?>?silica (–SiOH group). The above results reveal the differences among bitumen subfractions and mineral types, allowing potential insights to the development of enhanced oil recovery, such as aqueous-nonaqueous hybrid extraction process, solvent extraction, CO2-enhanced oil recovery, etc.Li, X., Fan, F., Zhang, B., Zhang, K., Chen, B., 2018. Biosurfactant enhanced soil bioremediation of petroleum hydrocarbons: Design of experiments (DOE) based system optimization and phospholipid fatty acid (PLFA) based microbial community analysis. International Biodeterioration & Biodegradation 132, 216-225. microbial mechanisms in nutrient and biosurfactant enhanced soil bioremediation of petroleum hydrocarbons (PHCs) were investigated. A systematic factorial design was conducted and a response surface reduced quadratic model was developed to determine the effects of nutrients and two surfactants (i.e., rhamnolipids and Tween 80) in the 36-day PHC degradation. A significant effect was observed from nutrient addition and a 92.3% removal of PHCs was achieved by applying rhamnolipids at a concentration of 150?mg/kg and nutrient solution at 1000?μL. Rhamnolipids promoted higher metabolic activities of indigenous soil microorganisms to assimilate hydrocarbons than Tween 80 during the kinetic investigation. Phospholipid fatty acid (PLFA) analysis indicated three different microbial transformation patterns were observed when the soils were treated by natural attenuation, enhanced by rhamnolipids and Tween 80, respectively. As indicated by PLFA biomarkers of the Gram-negative bacterial populations (cy17:0, cy19:0, 16:1ω7c and 18:1ω7c), Gram-negative bacteria are closely correlated with the amount of total soil biomass and are the sources of hydrocarbon degraders. PLFA compositional characteristics were also used to evaluate the physiological status of the indigenous microorganisms and elucidate biodegradation mechanisms linked to different soil treatments.Li, X., Kang, Y., Zhou, L., 2018. Investigation of gas displacement efficiency and storage capability for enhanced CH4 recovery and CO2 sequestration. Journal of Petroleum Science and Engineering 169, 485-493. gas into coal seam is an effective technique for enhanced coalbed methane recovery and CO2 sequestration. Displacement efficiency of various gas injections was investigated by experimental measurements. Experimental results show that any factor of adsorption amount, back pressure, displacement pressure and displacement time can have a significant influence on methane recovery. Displacement efficiency has a non-monotonic increase with the ascending equilibrium pressure, is enhanced by back pressure reduction and increasing displacement pressure, and tends to reach a higher degree by the mixture rich in nitrogen. Displacement pressure presents a significant influence on displacement efficiency and causes a rapid production response in early injection stage for the rich nitrogen mixture. Displacement dynamics of various gas injections was investigated by the numerical simulation. A good consistency of displacement efficiency by displacement experiment and numerical simulation is found. For the mixture rich in nitrogen, the higher displacement efficiency is obtained and the breakthrough time of N2 and CO2 can be both shortened. Spatial and temporal distribution of adsorbed gas for pure gas injection shows that the displacement and breakthrough time of pure CO2 are both delayed. Based on spatial and temporal distribution of mixed gas displacement, displacement efficiency is controlled by the composition and competitive sorption of the mixture. Gas transport is sensitive to the injection pressure and faster to reach the stable state with the ascending pressure. The result of this study is helpful to realize the mechanism of enhanced coalbed methane recovery by gas injection and design the scheme of gas injection.Li, X., Zhang, J., Wang, Y., Guo, M., Wang, Z., Wang, F., 2018. Accumulation condition and favorable area evaluation of shale gas from the?Niutitang Formation in northern Guizhou, South China. Journal of Natural Gas Geoscience 3, 1-10. order to investigate the potential of the Lower Cambrian shale gas in South China, a study on the accumulation condition of shale gas from the Niutitang Formation was conducted. In addition, the favorable accumulation area of shale gas in northern Guizhou was evaluated. The study and evaluation were both analyzed according to the geochemical analysis data of the core and outcrop samples in this paper. The result shows that the Niutitang Formation shale in northern Guizhou is formed in the shallow sea sedimentary environment, which features moderate buried depth (<3000?m), high organic-rich shale thickness (30–110?m), high organic abundance (average TOC>3.0%), type I kerogens, over-mature thermal evolution level (Ro>2.0%), low porosity, abundant micro- and nano-meter pores and fractures, rich brittle mineral (average content >40%), and relatively high gas content (average 1.5?m3/t). The aforementioned feature indicates that the Niutitang Formation in northern Guizhou has good accumulation condition for shale gas. Through the studies above, it is proposed that the southeastern Shiqian—Yuqing—Shibing area is the most favorable area for shale gas accumulation in northern Guizhou.Li, Y., Liu, Y., Jiang, D., Xu, J., Zhao, X., Hou, Y., 2018. Effects of weathering process on the stable carbon isotope compositions of polycyclic aromatic hydrocarbons of fuel oils and crude oils. Marine Pollution Bulletin 133, 852-860. fuel oils and two crude oils were subjected to a 60-day weathering simulation experiment, and the effects of weathering on some common parameters for aromatics and aromatic δ13C values were studied. The results show that weathering of all oil samples affected little the DBT/P (dibenzothiophene/phenanthrene) ratio and methylphenanthrene distribution fraction. Four oil samples could be distinguished only by the DBT/P ratio. The effect of weathering on isotopes in polycyclic aromatic hydrocarbons was small. The results show that the types of four oil samples can be distinguished, while Kuwait and Russia crude oils cannot be discriminated from each other totally by double-coordinate two-dimensional maps for aromatic δ13C; all of the oil samples can be distinguished by principal component analysis of δ13Cfor aromatics, the relationship of DBT/P and PAHs δ13C values. Therefore, the δ13C value of aromatics can be used as an alternative index for the analysis of oil spills.Li, Z., Lu, Y., Guo, Y., Cao, H., Wang, Q., Shui, W., 2018. Comprehensive evaluation of untargeted metabolomics data processing software in feature detection, quantification and discriminating marker selection. Analytica Chimica Acta 1029, 50-57. analysis represents a key challenge for untargeted metabolomics studies and it commonly requires extensive processing of more than thousands of metabolite peaks included in raw high-resolution MS data. Although a number of software packages have been developed to facilitate untargeted data processing, they have not been comprehensively scrutinized in the capability of feature detection, quantification and marker selection using a well-defined benchmark sample set. In this study, we acquired a benchmark dataset from standard mixtures consisting of 1100 compounds with specified concentration ratios including 130 compounds with significant variation of concentrations. Five software evaluated here (MS-Dial, MZmine 2, XCMS, MarkerView, and Compound Discoverer) showed similar performance in detection of true features derived from compounds in the mixtures. However, significant differences between untargeted metabolomics software were observed in relative quantification of true features in the benchmark dataset. MZmine 2 outperformed the other software in terms of quantification accuracy and it reported the most true discriminating markers together with the fewest false markers. Furthermore, we assessed selection of discriminating markers by different software using both the benchmark dataset and a real-case metabolomics dataset to propose combined usage of two software for increasing confidence of biomarker identification. Our findings from comprehensive evaluation of untargeted metabolomics software would help guide future improvements of these widely used bioinformatics tools and enable users to properly interpret their metabolomics results.Liang, T., Li, Q., Liang, X., Yao, E., Wang, Y., Li, Y., Chen, M., Zhou, F., Lu, J., 2018. Evaluation of liquid nanofluid as fracturing fluid additive on enhanced oil recovery from low-permeability reservoirs. Journal of Petroleum Science and Engineering 168, 390-399. fracturing creates a complex fracture network that makes the oil production from low-permeability reservoirs economical. However, significant amount of water is likely lost into the rock matrix during hydraulic fracturing. This can cause formation damage due to multiphase flow, thus hindering the oil production rate. Surfactants can alter rock wettability and/or reduce oil-water interfacial tension (IFT), and it has been proposed to be used to mitigate such water blockage and enhance oil recovery. Among different approaches of using surfactants, forming liquid nanofluid (LNF) can minimize the adsorption of surfactants on rock surface, and it is likely to be one of the best options for low-permeability rocks with extensive surface area. In this study, the key properties of a well-screened LNF are evaluated, and then compared with a commercial flowback surfactant (CFS) that is widely used in the field. Pressure transmission test is further applied, which can determine the change of rock permeability due to different fluids and the potential formation damage due to multiphase flow. A systematic evaluation method is thus established to screen fracturing fluid additives to enhance oil production from low-permeability reservoirs both effectively and efficiently.Liu, B., Zhao, C., Ma, J., Sun, Y., Püttmann, W., 2018. The origin of pale and dark layers in Pliocene lignite deposits from Yunnan Province, Southwest China, based on coal petrological and organic geochemical analyses. International Journal of Coal Geology 195, 172-188. set of 39 pale lignite and dark lignite samples, obtained from a profile of the Pliocene Jinsuo lignite basin, Yunnan Province, China, were analyzed using coal petrology and biomarkers to determine whether changes in the depositional environment and/or vegetation caused the color changes ultimately observed in the lignites. A comprehensive analysis of all the data obtained revealed significant differences in the petrological and geochemical composition of the two lignite types.The pale lignites are characterized by a higher abundance of the liptinite group compared with the dark lignites. The composition of liptinites is dominated by bituminite (mineral-bituminous groundmass) and sporinite, along with a relatively low abundance of the huminite group. This indicates a higher degree of oxidation in the drier, more elevated peatland environments during deposition of the pale lignites. The low values of the tissue preservation index (TPI), vegetation index (VI), and gelification index (GI) in the pale lignites suggest a relatively high decomposition rate of plant materials under dry/aerobic conditions. In contrast, the dark lignites have a very high proportion of huminite dominated by ulminite, along with a low content of liptinite and inertinite macerals, which suggests the prevalence of wet/anaerobic conditions in the peat-forming mire. The high values of TPI, VI, and GI in the dark layers suggest better preservation of organic matter during deposition under anaerobic conditions, and more wet/humid climatic conditions, when compared with the pale lignites.With respect to the biomarker composition, the high concentrations of long-chain (C27-C31) n-alkanes in both pale and dark lignites are typical characteristics for the predominance of higher terrestrial plants. Significant concentrations of mid-chain n-alkanes (n-C21-C25) were detected preferentially in the dark lignites, suggesting that aquatic plants might also have contributed to the plant community during the formation of the dark layers. The content of diterpenoids, and the average ratio of diterpenoids to the sum of diterpenoids and triterpenoids (Di-/(Di-?+?Tri-terpenoids)) are higher in the pale lignites than in the dark lignites. This indicates that gymnosperms made a crucial contribution to the plant community during the formation of the pale lignites. In the dark lignites, triterpenoids are generally far more abundant than diterpenoids, which suggests that the dark layers were overwhelmingly formed by angiosperm plants. This is consistent with lower C/N ratios in the dark lignite layers (av. 40.8) compared with the pale lignite layers (av. 60.6). Higher microbial activities in the pale lignites than in the dark lignites are reflected by the higher concentration of hopanoids and 17α,21β-homohopane (22R) in the pale lignites.Liu, C., McGovern, G.P., Liu, P., Zhao, H., Horita, J., 2018. Position-specific carbon and hydrogen isotopic compositions of propane from natural gases with quantitative NMR. Chemical Geology 491, 14-26. isotope compositions of light hydrocarbons are expected to provide valuable information on their formation and migration-degradation processes. Here we present a high-accuracy and high-precision (≤±10 and ≤±1‰ for 2H and 13C isotope compositions, respectively) method to determine position-specific hydrogen and carbon isotope compositions of propane from natural gases with quantitative NMR. Customized, light-weight high-pressure sapphire NMR cells were developed for liquefied propane samples. Precision and accuracy of our technique were demonstrated using 13C-labeled compounds, neat samples of C3-C5 with natural isotope abundances, and inter-laboratory comparison of a C7 sample. To determine position-specific isotope compositions of propane from natural gas samples, a method was developed to collect and purify large amount (~6.8?mmol) of propane, using a variable-temperature cold trap. A test with a synthetic sample of natural gas mixture indicates that little isotope fractionation occurred during the propane separation and purification from natural gas mixtures. For the first time, high-precision and high accuracy data are reported of position-specific carbon and hydrogen isotope compositions of propane from different sources, including conventional and unconventional petroleum reservoirs. Preliminary results show that position-specific isotope fractionations between the center and terminal sites of propane vary widely for the different sources. Position-specific isotope compositions of propane have the potential to improve our understanding on the origins, migration and degradation processes of natural gas and hydrocarbons in general.Liu, C., Wang, Z., Macdonald, F.A., 2018. Sr and Mg isotope geochemistry of the basal Ediacaran cap limestone sequence of Mongolia: Implications for carbonate diagenesis, mixing of glacial meltwaters, and seawater chemistry in the aftermath of Snowball Earth. Chemical Geology 491, 1-13. seawater chemistry and oceanographic information associated with Snowball Earth are commonly inferred from the geochemistry of cap carbonates deposited on continental margins during and after deglaciation. However, interpretation of such records can be complicated by carbonate diagenesis and contamination from siliciclastic components. In an attempt to disentangle these effects, we studied the geochemistry of the post-Marinoan cap carbonate sequence from Mongolia using a step-leaching procedure, which revealed that most samples are heterogeneous with respect to multiple geochemical signatures, including trace element concentrations, Sr, Mg, C and O isotopic signatures, raising questions to previous studies applying carbonate bulk-rock geochemistry for paleoenvironment reconstructions. Such sample heterogeneity can be explained by contamination from non-carbonate phases and carbonate alteration. After stepped leaching, the least-altered/contaminated geochemical signatures for each sample were identified and the influences of carbonate diagenesis were evaluated. Our data indicate that mixing of glacial meltwater persisted to the maximum flooding surface within the cap carbonate sequence, below which carbonates record significant Mg and Sr isotope fluxuations that are most readily interpreted in the context of the mixing of water masses having distinct isotopic compositions. Only limestones deposited above the maximum flooding surface formed in a well-mixed ocean and exhibit Mg and Sr isotope values that record the integrated effects of Snowball Earth on ocean chemistry. Our study cautions against interpreting the geochemistry of cap carbonates in terms of whole ocean geochemical cycles.Liu, F.-J., Gasem, K.A.M., Tang, M., Goroncy, A., He, X., Huang, Z., Sun, K., Fan, M., 2018. Mild degradation of Powder River Basin sub-bituminous coal in environmentally benign supercritical CO2-ethanol system to produce valuable high-yield liquid tar. Applied Energy 225, 460-470. novel and environmentally benign binary supercritical fluid system, comprised of supercritical CO2 and ethanol (SCCO2-ethanol), was employed to convert coal, a conventional energy resource, into high-value liquid tar which can be used as feedstock for the production of fuels/chemicals and carbon fibers. The SCCO2-ethanol system shows good performance for producing valuable liquid tar in high yield from Powder River Basin sub-bituminous coal. The results show that the highest yield of liquid tar reaches up to approximate 38?wt% (38?g/100?g raw coal) at 350?°C, and that SCCO2 can promote the liquid tar yield by 5.6?wt% compared to that using pure ethanol due to the synergistic effect between ethanol and SCCO2. The liquid tars are better candidates as clean fuels than the raw coal or even bituminous coal due to their higher heating values and almost free from ash. The liquid tars from degradation in SCCO2-ethanol (liquid tarSCCO2-ethanol) and in ethanol without SCCO2 (liquid tarethanol) at 350?°C were characterized with multiple analytical techniques. Fourier transform infrared analyses indicated that both liquid tars have similar distributions of functional groups. The proportion of volatile and small-molecular species in liquid tarSCCO2-ethanol is higher than liquid tarethanol according to thermogravimetric analysis. Further, gas chromatograph/mass spectrometry analyses show that phenols and aliphatic esters are the dominant volatile compounds in both liquid tars. The 1H and 13C nuclear magnetic resonance analyses reveal that both liquid tars have low aromaticity and liquid tarSCCO2-ethanol contains more aromatic carbons than liquid tarethanol, especially highly condensed aromatic carbons. Methylene and aliphatic and aromatic CH3 are the major aliphatic moieties in both liquid tars. The liquid tars can be separated into light oil and asphaltene fractions by extraction with n-heptane. In addition, the asphaltene fraction has potential to be used as the precursor for fabricating carbon nanofibers via electrospinning. Possible mechanisms for releasing volatile compounds and asphaltene from Powder River Basin sub-bituminous coal by SCCO2-ethanol degradation were also discussed.Liu, H., Yang, H., Cao, Y., Liu, W., 2018. Compound-specific δD and its hydrological and environmental implication in the lakes on the Tibetan Plateau. Science China Earth Sciences 61, 765-777. hydrogen isotopic composition (δD) of n-alkanes in lacustrine sediments is widely used in palaeoenvironmental studies, but the heterogeneous origins and relative contributions of these lipids provide challenges for the interpretation of the increasing dataset as an environment and climatic proxy. We systematically investigated n-alkane δD values from 51 submerged plants (39 Potamogeton, 1 Myriophyllum, and 11 Ruppia), 13 algae (5 Chara, 3 Cladophora, and 5 Spirogyra) and 20 terrestrial plants (10 grasses and 10 shrubs) in and around 15 lakes on the Tibetan Plateau. Our results demonstrate that δD values of C29 n-alkane are correlated significantly with the lake water δD values both for algae (R2 = 0.85, p<0.01, n=9) and submerged plants (R2 =0.90, p<0.01, n=25), indicating that δD values of these algae and submerged plants reflect the δD variation of lake water. We find that apparent hydrogen isotope fractionation factors between individual n-alkanes and water (εa/w) are not constant among different algae and submerged plants, as well as in a single genus under different liminological conditions, indicating that the biosynthesis or environmental conditions (e.g. salinity) may affect their δD values. The δD values of submerged plant Ruppia in the Xiligou Lake (a closed lake) are significant enriched in D than those of terrestrial grasses around the lake (one-way ANOVA, p<0.01), but the algae Chara in the Keluke Lake (an open lake) display similar δD values with grasses around the lake (one-way ANOVA, p=0.826>0.05), suggesting that the n-alkane δD values of the algae and submerged plants record the signal of D enrichment in lake water relative to precipitation only in closed lakes in arid and semi-arid area. For each algae and submerged plant sample, we find uniformed δD values of different chain length n-alkanes, implying that, in combination with other proxies such as Paq and Average Chain Length, the offset between the δD values of different chain length n-alkanes can help determine the source of sedimentary n-alkanes as well as inferring the hydrological characteristics of an ancient lake basin (open vs closed lake).Liu, J., Liang, W., Kang, Z., Lian, H., Geng, Y., 2018. Study on the quantitative model of oil shale porosity in the pyrolysis process based on pyrolysis kinetics Oil Shale 35, 128–143. of the porosity variation of oil shale during the pyrolysis process is of great importance in understanding the migration mechanism of pyrolysis products. Using the Fushun oil shale of China as an example and taking into account the fact that the porosity change of oil shale arises from pyrolysis of kerogen at high temperature, in this paper, the thermal curve of oil shale was employed to obtain its pyrolysis rate equation. A quantitative model of oil shale porosity during pyrolysis was constructed. The porosity of oil shale under different pyrolysis conditions was determined using the conventional method, computed tomography (CT) and the mercury intrusion method. The calculated results were in good agreement with the experimental data.Liu, K., Ostadhassan, M., Kong, L., 2018. Multifractal characteristics of Longmaxi Shale pore structures by N2 adsorption: A model comparison. Journal of Petroleum Science and Engineering 168, 330-341. adsorption is one of the most widely used techniques to assess pore structures of shale samples due to its ability for characterizing pores in nanoscale. Various models have been developed to quantify pore structures based on adsorption isotherms. In this regard, using a suitable model can give us more accurate pore structure information. The Barret, Joyner and Halenda (BJH) model along with density functional theory (DFT), two most frequently used ones for pore structures of shales, employed on Longmaxi shale samples and compared. BJH model can be divided into two sub-models: adsorption (BJHAD) and desorption (BJHDE). First, the multifractal analysis was used to quantify the heterogeneity of pore size distributions derived from these models. Second, partial least regression analysis (PLS) was employed to quantify the correlations between pore structures and rock compositions. The results showed that pore structures (volume and surface area) and pore heterogeneity derived from BJHAD, BJHDE and DFT model would differ. In addition, PLS results indicated that minerals (except dolomite and clay) and organic matter would correlate positively while clay minerals negatively with pore surface area and volume independent of the method that was used. Finally, the comparison of results from these three methods demonstrated that DFT model is superior to BJHAD and BJHDE for pore structure characterization in shale gas formations.Liu, M., Huang, X., Liu, Q., Chen, M., Liao, S., Zhu, F., Shi, S., Yang, H., Chen, X., 2018. Rapid screening and identification of antioxidants in the leaves of Malus hupehensis using off‐line two‐dimensional HPLC–UV–MS/MS coupled with a 1,1′‐diphenyl‐2‐picrylhydrazyl assay. Journal of Separation Science 41, 2536-2543. leaves of Malus hupehensis have a strong antioxidant activity and are commonly consumed as a healthy tea. However, detailed information about its antioxidants is incomplete. Herein, we developed an effective strategy based on combining off‐line two‐dimensional high‐performance liquid chromatography with ultraviolet and tandem mass spectrometry detection with a 1,1′‐diphenyl‐2‐picrylhydrazyl assay to rapidly screen and identify the antioxidants from the leaves of M. hupehensis. In the orthogonal two‐dimensional liquid chromatography system, a Venusil HILIC column was used for the first dimension, while a Universil XB‐C18 column was installed in the second dimension. As a result, 32 antioxidants, including ten dihydrochalcones, two flavanones, nine flavonols, four flavones, and seven phenolic acids were tentatively identified, out of which 23 compounds, as far as we know, were isolated and characterized from the leaves of M. hupehensis for the first time. To the best of our knowledge, this is the first systematic investigation of the antioxidants from the leaves of M. hupehensis. The results indicated that the proposed method is an efficient technique to rapidly investigate antioxidants, especially for coeluted and minor compounds in a complex system. Liu, S., Wu, C., Li, T., Wang, H., 2018. Multiple geochemical proxies controlling the organic matter accumulation of the marine-continental transitional shale: A case study of the Upper Permian Longtan Formation, western Guizhou, China. Journal of Natural Gas Science and Engineering 56, 152-165. organic-rich shale of the Longtan Formation of the Upper Permian in western Guizhou formed during the marine-continental transitional facies depositional environment. With a high total organic carbon (TOC) content and a large cumulative thickness, it is thought to be the superior source rock for shale gas development. The depositional environment of marine-continental transitional shale is significantly different from marine shale, which leads to the various accumulation characteristics of the organic matter. In this paper, shale samples were collected from the Longtan Formation of the Upper Permian, which is typical marine-continental transitional shale. The TOC, major elements and trace elements were measured, and the formation and preservation conditions were investigated using multiple geochemical proxies, including paleoclimate, detrital influx, redox parameters, paleoproductivity and sedimentation rate. The TOC decreases first and then increases from the bottom to the top of the Longtan Formation shale, and the TOC for the lower Longtan Formation is higher than the upper Longtan Formation. For the lower Longtan Formation, the positive correlations between TOC and redox indicators (V, U and V/Cr) demonstrate that the dysoxic bottom water environment was the key factor that controlled the accumulation of organic matter. For the upper Longtan Formation, there are positive correlations between the TOC and the paleoclimate and sedimentation rate, which suggests that the enrichment of the organic matter was influenced by both a warm and humid paleoclimate and the high sedimentation rate of an oxic environment. However, the high detrital influx (aluminosilicate) occurred as the diluent decreased the concentration of organic matter. The paleoproductivity has a poor correlation with TOC for the Longtan Formation, suggesting that it was inferior to the gathering of organic matter. The sedimentary models built for the upper and lower Longtan Formation shale can reproduce the enrichment of organic matter.Liu, W., Liao, Y., Pan, Y., Jiang, B., Zeng, Q., Shi, Q., Hsu, C.S., 2018. Use of ESI FT–ICR MS to investigate molecular transformation in simulated aerobic biodegradation of a sulfur-rich crude oil. Organic Geochemistry 123, 17-26. an understanding of the biodegradation of organic sulfur compound(s) (OSC) in crude oils has been hampered by limitations in separation methods and analytical techniques. In this study, a simulated aerobic biodegradation experiment was performed on a sulfur-rich crude oil, from which a series of biodegraded oils from slight to moderate degrees of biodegradation were obtained. Molecular transformations in these biodegraded oils were investigated by gas chromatography–mass spectrometry (GC–MS) and Fourier transform ion cyclotron resonance mass spectrometry (FT–ICR MS) under both positive- and negative-ion electrospray ionization (ESI) modes. The variations in the distributions of saturated hydrocarbons, OSCs, and acidic components during aerobic biodegradation were studied. A gradual decrease of OSCs with alkyl chains during biodegradation, especially in those with few sulfur-containing or naphthenic/aromatic rings, was observed. In addition, sulfur-containing phenols with alkyl chains also exhibited a trend of gradual decrease similar to alkyl phenols, with fewer ring numbers being more susceptible to biodegradation. The biodegradation pathways for OSCs and sulfur-containing acids, as well as certain other heteroatomic compounds, are discussed. Terminal oxidation, rather than sulfur-specific degradation, is the more likely biodegradation pathway of these OSCs, as in the case of n-alkanes in this study. Sulfur-containing carboxylic acids may be the biodegradation products of these OSCs.Liu, X., Li, D., Yang, Z., Wang, S., Pei, L., Shao, R., Niu, M., Li, W., 2018. Investigation on the structure of low-temperature coal tar asphaltene precipitated with different n-alkane solvents. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 40, 1226-1233. study the effects of deasphalting solvents on asphaltene, n-pentane asphaltene (As-5), n-heptane asphaltene (As-7), and soluble in n-heptane but insoluble in n-pentane asphaltene (As-(5–7)) were precipitated from low-temperature coal tar. Gel Permeation Chromatography (GPC), nuclear magnetic resonance (NMR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) are used to analyze their structure. The results show that As-(5–7) is composed of the aromatic layer periphery of As-5, so the aromatic degree of As-(5–7) is lower and the content of alkyl and naphthenic base groups is larger. What is more, the aromatic ring consistency and condensation degree of As-(5–7), As-5, and As-7 increase gradually, so their coking potential and hydrogenating difficulty increase.Liu, X., Liu, H., Xing, L., Yin, Y., Wang, J., 2018. Seismic low-frequency shadow beneath gas hydrate in the Shenhu area based on the stereoscopic observation system. Journal of Earth Science 29, 669-678. analysis shows a low-frequency shadow under the BSR interface. Traditional low-frequency shadow analysis is based on stacked data. In order to understand the BSR low-frequency shadow more clearly, a frequency division analysis on stereoscopic observation seismic data based on the adaptive optimal-kernel (AOK) frequency analysis method is presented. It includes ocean-bottom seismometer (OBS) data (common receiver point data including vertical and horizontal components), vertical cable data (common receiver point data) and horizontal cable data (stacked section of different offsets). The OBS data frequency analysis gets a conclusion that vertical component has a significant effect on the low-frequency shadow, but the horizontal component did not. The vertical cable data shows that the low frequency band of vertical cable is wider than OBS. And then the horizontal cable data frequency analysis points out that the bigger the angle of incidence is, the more obvious the low-frequency shadow will be. The low-frequency shadow feature is shown in the stereoscopic observation field and the visual effect on common reception point data is better. The lateral reservoir distribution characteristics are predicted from low-frequency shadow feature analysis of the hydrate BSR based on stereoscopic observation.Liu, X., Zhang, J., Liu, Y., Huang, H., Liu, Z., 2018. Main factors controlling the wettability of gas shales: A case study of over-mature marine shale in the Longmaxi Formation. Journal of Natural Gas Science and Engineering 56, 18-28. plays a significant role in the exploration and exploitation of shale gas. However, it is challenging to evaluate the wettability of gas shale due to the complexity and heterogeneity of the mineral components, physical properties, and pore structures. In this study, we conduct rock composition analysis, field gas desorption, and air-liquid contact angle measurements for 15 core samples, and analyze the petrophysical properties of 8 core samples from the YY3 well drilled in the Longmaxi Formation, Hunan Province, Southern China. A strong parabolic correlation was found between water contact angles and total organic carbon (TOC) content. We divided the samples into two analysis groups using the symmetry axis with TOC ≈1.5%. Scanning Electron Microscope (SEM) analysis demonstrated that migratory organic matter is sparsely distributed in samples with TOC?<?1.5%. However, in the samples with TOC >1.5%, the migratory organic matter appeared to be like a uniformly distributed network. This suggests that migratory organic matter increases the water contact angle and is a significant factor explaining strong oil-wetting with high TOC. A negative correlation was found between the content of illite and the water contact angle (R2?=?0.9070), while a positive correlation exists between the illite/smectite mixed layer and the water contact angle (R2?=?0.8048). This relationship is likely due to the large inner surface area of the structure layer in the illite/smectite mixed layer, allowing for chemical adsorption of organic matter. Additionally, a positive correlation between TOC and total gas content was identified. Pore throat analysis and SEM imaging demonstrated that organic pores constitute a significant portion of porosity. Nevertheless, the negative correlation between total gas content and the water contact angle indicated that gas occupies the pore space which previously stored degraded asphalt. Eventually, identifying the main factors that influence the water contact angle of gas shales provides a new mode diagram to analyze the wettability of over-mature marine gas shales.Liu, Y., Tang, X., Zhang, J., Mo, X., Huang, H., Liu, Z., 2018. Geochemical characteristics of the extremely high thermal maturity transitional shale gas in the Southern North China Basin (SNCB) and its differences with marine shale gas. International Journal of Coal Geology 194, 33-44. great number of studies have been carried out on the geochemical characteristics of marine shale gas from the lower Silurian Longmaxi Formation in the Sichuan Basin. However, a systematic study on geochemical and isotopic characteristics of transitional shale gas (gas from the alternating marine-terrigenous shale facies) has not been well addressed. In the present study, transitional shale gas from the lower Permian Shanxi (P1s) and Taiyuan (P1t) Formation in the Southern North China Basin (SNCB) were collected and analyzed for their geochemical and isotopic compositions. The hydrocarbon gases are dominated by methane, with small amounts of ethane, without propane and butane, which is consistent with the extremely high thermal maturity of the gas shales (RO% values between 3.2 and 4.2%). Compared with marine shale gas, the relatively high non-hydrocarbon components may be associated with the humic source rocks. The δ13C1 values range from ?31.6‰ to ?21.0‰ and the δ13C2 values range from ?35.9‰ to ?26.1‰, the δ2HCH4 values range from ?221‰ to ?138‰. These results indicate that the gases are of thermogenic origin, methane with anomalous heavy carbon isotopic and light hydrogen isotopic values was interpreted as redox reactions of gases with transition metals and water at maximum burial resulting in Rayleigh-type fractionation. The difficulties of identifying marine and transitional shale gas may be due to the complete or partial carbon isotopic reversal caused by secondary alteration and the extremely high thermal maturity of the gas shales. CO2 concentration and δ13C(CO2) values suggest that CO2 in the transitional shale gas was mainly thermogenic origin and formed together with hydrocarbon generation. Furthermore, significant differences can be observed from the CO2 in different types of shale gas, CO2 in the transitional shale gas is mainly distributed in areas with CO2?>?5% and δ13C(CO2)?<??8‰, while CO2 in the marine shale gas is mainly distributed in areas with CO2?<?5% and δ13C(CO2)?>??8‰. The δ15N(N2) values and high illite and illite-smectite mixed clay (I/S) content suggest that nitrogen in transitional shale gas was possibly generated during thermo-ammoniation of organic matter and/or the breakdown of NH4-rich clay minerals. In addition, based on the geochemical characteristics of marine and transitional shale gas, a geochemical pattern of shale gas is presented in this paper.Liu, Y., Zhu, Y., Liu, S., Li, W., 2018. A hierarchical methane adsorption characterization through a multiscale approach by considering the macromolecular structure and pore size distribution. Marine and Petroleum Geology 96, 304-314. structure of coal is known to be strongly heterogeneous in terms of size, shape and occurrence. The underlying sorption mechanisms are expected to be different depending on the type and size of pores. In this study, both experiments and numerical simulation were used to study sorption behavior of coal. Vitrinite maceral was chosen as the study material and the macerals were separated from Yilan subbituminous coals. Pores in vitrinite were categorized into two different types depending on the occurrence mechanisms and they are termed as elemental particle pore (EP pore) and molecular structure pores (MS pore). According to the pore structure and macromolecular structure, pore models of the two types of pores were established and used to numerically estimate the methane adsorption capacity. It was found that gas sorption varies significantly for different types of pores. Methane adsorption capacity of MS micropores is determined by the pore volume, and while that of EP pores is determined by the internal surface area due to the different sorption mechanisms. Methane adsorption in MS pores showed pore volume filling mechanism, and the methane adsorption results can be well modeled by Dubinin and Astakhov (D-A) model. On the contrary, two distinguishable adsorbed layers can be identified for in EP pore sorption, and the methane density of the first layer was much larger than that of the second layer, which is consistent with the BET model. Of the total gas adsorption amount in coal, the amount of absorbed methane in MS pores contributed a relatively large proportion compared to EP pores. With elevated gas pressure, the difference between these two mechanisms decreased, and when the pressure was 10?MPa, the proportion of methane adsorption in EP pores was ～40%. The overall measured gas adsorption isotherm is a sum of methane adsorption in different types of pores. The combination of simulation and experimental methods can provide more accurate and detailed information and help understand methane adsorption in coal.Liu, Z., Cheng, Y., Wang, L., Wang, H., Jiang, J., Li, W., 2018. Analysis of coal permeability rebound and recovery during methane extraction: Implications for carbon dioxide storage capability assessment. Fuel 230, 298-307. permeability rebound and recovery severely affect the efficiency of coalbed methane extraction and CO2 storage capability of coal seams, but theoretical research on it is insufficient now. Besides, ambiguity still remains in evolution laws of coal permeability rebound and recovery pressure with the change of various influencing factors. In this work, the focus is first placed on the influences of effective stress (considering engineering-strain and natural-strain) and adsorption-induced swelling (considering matrix bridge) on fracture aperture; then, a new evolution model of coal fracture aperture is established by adopting the competition mechanism of the two. At the same time, based on the correlation between the variation of fracture aperture and permeability using the classical cubic law, the evolution model of coal permeability is set up, of which is on the basis together with some reasonable assumptions to obtain the factors influencing permeability rebound and the recovery pressure. The evolution laws of coal permeability rebound and recovery under the influence of main factors are in detailed analysis. Specifically, permeability rebounds and recovers when the initial coal reservoir pressure is greater than its switching threshold. The greater the initial pressure, the larger the numerical range dropping from the initial value to rebound value, so does the effect of coal cleat compressibility. However, only on condition that the internal swelling coefficient is smaller than its switching threshold, the permeability will rebound and recover. Besides, the influencing mechanism of CO2 storage and CBM extraction on permeability evolution is the same, while the variation laws of permeability, of rebound and recovery especially, exert strong impact on CO2 storage capability. Therefore, the influence of various permeability evolution laws on CO2 storage capability is discussed macroscopically for valid assessment of it, providing guidance to select appropriate coal seams for CO2 storage.Lobo, L., Pereiro, R., Fernández, B., 2018. Opportunities and challenges of isotopic analysis by laser ablation ICP-MS in biological studies. TrAC Trends in Analytical Chemistry 105, 380-390. of natural isotopic abundances and isotope ratio variations in hard tissues (such as bone, tooth, coral skeletons and otoliths) either from radiogenic and/or stable isotopes can provide important information about human evolution, palaeoenvironmental reconstructions and provenance. Besides, the addition of stable isotopically-enriched isotopes to vegetables, animals, or even humans, allows the design of a wide variety of studies to track, understand or improve biological systems. Within this context, laser ablation (LA) coupled to inductively coupled plasma - mass spectrometry (ICP-MS) is being increasingly employed for direct isotopic analysis of solids, offering the possibility to perform analyses with high spatial resolution. In this review current research and instrumental developments devoted to isotope ratio analysis by LA-ICP-MS in hard and soft biological tissues are described together with some representative applications. An outlook of challenges and research opportunities within the field is also given.Loginova, A.N., Thomsen, S., Dengler, M., Lüdke, J., Engel, A., 2018. Diapycnal dissolved organic matter supply into the upper Peruvian oxycline. Biogeosciences Discussions 2018, 1-23. Eastern Tropical South Pacific (ETSP) hosts the Peruvian upwelling system, which represents one of the most productive areas in the world ocean. High primary production followed by rapid heterotrophic utilization of organic matter supports the formation of one of the most intense oxygen minimum zones (OMZ) in the world ocean where dissolved oxygen (O2) concentrations reach well below 1??mol?kg?1. The high productivity leads to an accumulation of dissolved organic matter (DOM) in the surface layers that may serve as a substrate for heterotrophic respiration. However, the importance of DOM utilization for O2 respiration within the Peruvian OMZ remains unclear so far. Here, we evaluate the diapycnal fluxes of O2, dissolved organic carbon (DOC), dissolved organic nitrogen, dissolved hydrolysable amino acids (DHAA) and dissolved combined carbohydrates (DCCHO) and the composition of DOM in the ETSP off Peru to learn, whether labile DOM is reaching into the core of the OMZ and how important DOM utilization might be for O2 attenuation. The observed diapycnal 2 flux (50?mmol?O2?m?2?day?1 at max) was limited to the upper 80?m of the water column, the flux attenuation of ~1??mol?L?1day?1, was comparable to previously published O2 consumption rates for the North and South Pacific OMZs. The diapycnal DOM flux (31?mmol?C?m?2?day?1 at max) was limited to ~30?m water depth, suggesting that the labile DOM is already utilized within the upper part of the shallow oxycline off Peru. The analyses of DCCHO and DHAA composition support this finding, suggesting that DOM undergoes comprehensive remineralization already within the upper part of the oxycline, as the DOM within the core of the OMZ was found to be largely altered. Estimated by a simple equation for carbon combustion, aerobic respiration of DCCHO and DHAA, supplied by diapycnal mixing (0.46??mol?L?1?day?1 at max), could account for up to 38?% of the diapycnal O2 supply in the upper oxycline, which suggests that DOM utilization may play a significant role for shape of the upper Peruvian oxycline.Loher, M., Marcon, Y., Pape, T., R?mer, M., Wintersteller, P., dos Santos Ferreira, C., Praeg, D., Torres, M., Sahling, H., Bohrmann, G., 2018. Seafloor sealing, doming, and collapse associated with gas seeps and authigenic carbonate structures at Venere mud volcano, Central Mediterranean. Deep Sea Research Part I: Oceanographic Research Papers 137, 76-96. release from the seafloor is commonly associated with chemosynthesis-based cold-seep ecosystems that facilitate the precipitation of authigenic carbonates. It has been proposed that carbonate growth results in self-sealing, but little is known regarding the evolution of cold-seep structures in relation to fluid migration pathways. This study investigates structures resulting from gas seepage along ring faults peripheral to Venere mud volcano (1600 m water depth), based on multibeam bathymetry and seafloor backscatter data collected by an autonomous underwater vehicle, together with photomosaics, video observations, and samples obtained by a remotely operated vehicle. Sites of focused fluid flow are identified by gas bubble streams rising from the seafloor while anaerobic oxidation of methane over wider areas is indicated by the occurrence of chemosynthesis-based organisms (microbial mats, vesicomyid clams, vestimentiferan tube worms). At some sites, flakes of gas hydrate were observed in the water column during sampling. A range of carbonate structures exists at these sites: 1) flat and extensive pavements; 2) mounds with disseminated nodules or cm-thick crusts; 3) fractured mounds with exposed, dm-thick crusts; and 4) seafloor depressions lined by dm-thick crusts. The mineralogy and stable carbon isotopic compositions of the carbonates are consistent with anaerobic oxidation of methane from thermogenic sources, and possible near-seabed influence of gas hydrate formation and dissolution. The seafloor expressions of seepage are inferred to be controlled by the interaction of fluid flow due to carbonate precipitation and gas hydrate formation. A conceptual model for mound development is proposed in the context of the known timescales of seep-colonization and rates of carbonate precipitation: (A) the onset of hydrocarbon-rich fluid-seepage through hemipelagic sediments leads to (B) the establishment of microbial mats on flat seafloor over decadal timescales and is followed by (C) the growth of pavements cemented by carbonates that seal the seafloor; over longer timescales (centuries to millennia), carbonate growth and subsurface gas hydrate formation/dissolution lead to (D) upward doming and fracturing of carbonate mounds, re-sealing and stacking of carbonates and in some cases to (E) their collapse to form depressions. Gas migration through fractures in the carbonates allows resealing and fuels AOM to provide habitats for chemosynthesis-based fauna. This evolutionary scenario is argued to be broadly applicable to the development of ruptured mounds and collapse features described at other seepage sites in the eastern Mediterranean Sea and elsewhere.Lomakina, A.V., Mamaeva, E.V., Pogodaeva, T.V., Kalmychkov, G.V., Khal’zov, I.A., Zemskaya, T.I., 2018. Anaerobic methane oxidation in enrichment cultures from deep sediments of a mud volcano Peschanka (South Baikal). Microbiology 87, 317-325. laboratory conditions, the microbial communities of bottom sediments of a mud volcano Peschanka (Lake Baikal) were found to carry out anaerobic methane oxidation (AOM). After 16 days of anaerobic cultivation of the enrichment cultures, methane content in the gas phase decreased, and microbial consortia were established. The content of carbon, nitrogen, and oxygen determined by energy dispersive X-ray spectroscopy (EDS) was higher than in the nearby sediment particles. The presence of bacteria of the NC10 phylum and archaea of the ANME-2d cluster was established by fluorescent in situ hybridization (FISH). Original Russian Text ? A.V. Lomakina, E.V. Mamaeva, T.V. Pogodaeva, G.V. Kalmychkov, I.A. Khal’zov, T.I. Zemskaya, 2018, published in Mikrobiologiya, 2018, Vol. 87, No. 3.Loomer, D.B., MacQuarrie, K.T.B., Al, T.A., Bragdon, I.K., Loomer, H.A., 2018. Temporal variability of dissolved methane and inorganic water chemistry in private well water in New Brunswick, Canada. Applied Geochemistry 94, 53-66. recent years, there have been a number of studies assessing water chemistry in private water supply wells in areas of unconventional oil and gas development. Many of the wells in these studies were only sampled once and a question remains as to how representative the results from a single sample are given the potential for temporal variability. To evaluate this issue, the temporal variability of water chemistry from fourteen private water wells in two study areas of southeastern New Brunswick was monitored on a monthly basis over the course of a year. The study areas had been the focus of unconventional natural gas development (the Sussex study area) or exploration (the Kent study area). Temporal data for dissolved methane, ethane and propane concentrations, the stable isotopes of carbon and hydrogen in methane, and inorganic chemistry were collected. In the Kent study area, there was little variation in water chemistry from the six wells studied, with the relative standard deviations (RSD) for methane ranging from 0 to 20%. This indicates that the water from these wells was not affected by seasonal factors such as changing temperature or hydrogeological conditions and that it is possible to acquire reproducible dissolved methane concentrations and water chemistry data from private water supply wells. The drillers’ logs for the Kent wells indicate that the casings were installed to depths that likely isolated the water-producing intervals from near-surface hydrogeochemical variations and that the majority of water drawn from the wells enters from a single, relatively high-yield, water-bearing zone. The temporal variability was higher in the eight wells located in the Sussex study area, with the RSDs for methane ranging from 18 to 141%. There were concurrent variations in inorganic parameters, suggesting that the changes in methane concentrations reflected hydrogeochemical fluctuations in the aquifers as opposed to sampling artifacts. The wells with the most variable water chemistry over time had multiple, often relatively low-yield, water-bearing zones. In those wells, methane was associated with Na-HCO3 water from relatively deep water-bearing zones, while dissolved oxygen (DO) and NO3 were associated with shallower, Ca-HCO3, groundwater. The presence of the redox-controlled species Mn, Fe, SO4 and H2S, did not appear to affect the temporal variability of methane.Loose, B., Naveira Garabato, A.C., Schlosser, P., Jenkins, W.J., Vaughan, D., Heywood, K.J., 2018. Evidence of an active volcanic heat source beneath the Pine Island Glacier. Nature Communications 9, Article 2431. landforms reveal that the West Antarctic Ice Sheet (WAIS) lies atop a major volcanic rift system. However, identifying subglacial volcanism is challenging. Here we show geochemical evidence of a volcanic heat source upstream of the fast-melting Pine Island Ice Shelf, documented by seawater helium isotope ratios at the front of the Ice Shelf cavity. The localization of mantle helium to glacial meltwater reveals that volcanic heat induces melt beneath the grounded glacier and feeds the subglacial hydrological network crossing the grounding line. The observed transport of mantle helium out of the Ice Shelf cavity indicates that volcanic heat is supplied to the grounded glacier at a rate of ~?2500?±?1700?MW, which is ca. half as large as the active Grimsv?tn volcano on Iceland. Our finding of a substantial volcanic heat source beneath a major WAIS glacier highlights the need to understand subglacial volcanism, its hydrologic interaction with the marine margins, and its potential role in the future stability of the WAIS.Lopes, S.P., Azevedo, N.F., Pereira, M.O., 2018. Quantitative assessment of individual populations within polymicrobial biofilms. Scientific Reports 8, Article 9494. appropriate tools providing reliable quantitative measures of individual populations in biofilms is critical as we now recognize their true polymicrobial and heterogeneous nature. Here, plate count, quantitative real-time polymerase chain reaction (q-PCR) and peptide nucleic acid probe-fluorescence in situ hybridization (PNA-FISH) were employed to quantitate cystic fibrosis multispecies biofilms. Growth of Pseudomonas aeruginosa, Inquilinus limosus and Dolosigranulum pigrum was assessed in dual- and triple-species consortia under oxygen and antibiotic stress. Quantification methods, that were previously optimized and validated in planktonic consortia, were not always in agreement when applied in multispecies biofilms. Discrepancies in culture and molecular outcomes were observed, particularly for triple-species consortia and antibiotic-stressed biofilms. Some differences were observed, such as the higher bacterial counts obtained by q-PCR and/or PNA-FISH (≤4 log10 cells/cm2) compared to culture. But the discrepancies between PNA-FISH and q-PCR data (eg D. pigrum limited assessment by q-PCR) demonstrate the effect of biofilm heterogeneity in method’s reliability. As the heterogeneity in biofilms is a reflection of a myriad of variables, tailoring an accurate picture of communities? changes is crucial. This work demonstrates that at least two, but preferentially three, quantification techniques are required to obtain reliable measures and take comprehensive analysis of polymicrobial biofilm-associated infections.López‐Comino, J.A., Cesca, S., 2018. Source complexity of an injection induced event: The 2016 Mw 5.1 Fairview, Oklahoma Earthquake. Geophysical Research Letters 45, 4025-4032.: Complex rupture processes are occasionally resolved for weak earthquakes and can reveal a dominant direction of the rupture propagation and the presence and geometry of main slip patches. Finding and characterizing such properties could be important for understanding the nucleation and growth of induced earthquakes. One of the largest earthquakes linked to wastewater injection, the 2016 Mw 5.1 Fairview, Oklahoma earthquake, is analyzed using empirical Green's function techniques to reveal its source complexity. Two subevents are clearly identified and located using a new approach based on relative hypocenter‐centroid location. The first subevent has a magnitude of Mw 5.0 and shows the main rupture propagated toward the NE, in the direction of higher pore pressure perturbations due to wastewater injection. The second subevent appears as an early aftershock with lower magnitude, Mw 4.7. It is located SW of the mainshock in a region of increased Coulomb stress, where most aftershocks relocated. Plain Language Summary Understanding the process of nucleation and rupture growth of natural and induced earthquakes is important for the assessment and mitigation of the corresponding time‐dependent hazard. Advanced earthquake source analysis reveals significant properties such as rupture geometry, preferred direction of rupture propagation, and the configuration of main slip patches in an earthquake rupture. This work use the seismic recording of foreshocks and aftershocks to invert the source complexity of one of the largest earthquakes linked to wastewater injection, the 2016 Mw 5.1 Fairview, Oklahoma earthquake. Two subevents are clearly identified and their centroids are located with respect to the hypocenter. The first subevent has a magnitude of Mw 5.0 showing the main rupture propagated toward the NE, in the direction where the most of the wastewater injection activity is concentrated. The second subevent appears as an early aftershock with lower magnitude, Mw 4.7, located SW where most aftershocks were relocated. These results have important implications to discuss the role of anthropogenic stress perturbation in controlling the direction and extent of the earthquake rupture growth. Lovell, A.E., Srinivasan, S., Karra, S., O'Malley, D., Makedonska, N., Viswanathan, H.S., Srinivasan, G., Carey, J.W., Frash, L.P., 2018. Extracting hydrocarbon from shale: An investigation of the factors that influence the decline and the tail of the production curve. Water Resources Research 54, 3748-3757. Understanding physical processes that control the long-term production of hydrocarbon from shale formations is important for both predicting the yield and increasing it. In this work, we explore the processes that could control the tail of the production curve by using a discrete fracture network method to calculate the total travel time from the rock matrix to small-scale fractures to the primary hydraulic fracture network. The factors investigated include matrix diffusion, extent of the small-scale fracture zone (or tributary fracture zone/TFZ) consisting of natural, reactivated and induced fractures, and the percentage of free hydrocarbon in the primary fracture network. Individual and combined parameter spaces are explored for each of these to understand the limits of these parameters as well as any systematic correlations between pairs of parameters. Although recent studies have shown that the matrix diffusion in virgin shale influences the production tail only after nearly 20 years, we demonstrate that matrix diffusion in the region of the TFZ significantly impacts production within the first year itself. Additionally, we found that the depth of TFZ fracturing region had no effect on the shape of the production curves although the total mass of the hydrocarbon produced increases with the depth. We also show that one can fit the production data using a site-specific set of parameters representing the diffusion in the TFZ, depth of the TFZ, and the free hydrocarbon in the large-scale fractures.Lowery, C.M., Bralower, T.J., Owens, J.D., Rodríguez-Tovar, F.J., Jones, H., Smit, J., Whalen, M.T., Claeys, P., Farley, K., Gulick, S.P.S., Morgan, J.V., Green, S., Chenot, E., Christeson, G.L., Cockell, C.S., Coolen, M.J.L., Ferrière, L., Gebhardt, C., Goto, K., Kring, D.A., Lofi, J., Ocampo-Torres, R., Perez-Cruz, L., Pickersgill, A.E., Poelchau, M.H., Rae, A.S.P., Rasmussen, C., Rebolledo-Vieyra, M., Riller, U., Sato, H., Tikoo, S.M., Tomioka, N., Urrutia-Fucugauchi, J., Vellekoop, J., Wittmann, A., Xiao, L., Yamaguchi, K.E., Zylberman, W., 2018. Rapid recovery of life at ground zero of the end-Cretaceous mass extinction. Nature 558, 288-291. Cretaceous/Palaeogene mass extinction eradicated 76% of species on Earth. It was caused by the impact of an asteroid on the Yucatán carbonate platform in the southern Gulf of Mexico 66 million years ago, forming the Chicxulub impact crater. After the mass extinction, the recovery of the global marine ecosystem—measured as primary productivity—was geographically heterogeneous; export production in the Gulf of Mexico and North Atlantic–western Tethys was slower than in most other regions, taking 300 thousand years (kyr) to return to levels similar to those of the Late Cretaceous period. Delayed recovery of marine productivity closer to the crater implies an impact-related environmental control, such as toxic metal poisoning , on recovery times. If no such geographic pattern exists, the best explanation for the observed heterogeneity is a combination of ecological factors—trophic interactions , species incumbency and competitive exclusion by opportunists —and ‘chance. The question of whether the post-impact recovery of marine productivity was delayed closer to the crater has a bearing on the predictability of future patterns of recovery in anthropogenically perturbed ecosystems. If there is a relationship between the distance from the impact and the recovery of marine productivity, we would expect recovery rates to be slowest in the crater itself. Here we present a record of foraminifera, calcareous nannoplankton, trace fossils and elemental abundance data from within the Chicxulub crater, dated to approximately the first 200 kyr of the Palaeocene. We show that life reappeared in the basin just years after the impact and a high-productivity ecosystem was established within 30 kyr, which indicates that proximity to the impact did not delay recovery and that there was therefore no impact-related environmental control on recovery. Ecological processes probably controlled the recovery of productivity after the Cretaceous/Palaeogene mass extinction and are therefore likely to be important for the response of the ocean ecosystem to other rapid extinction events.Lu, H., Liu, W., Sheng, W., 2018. Carbon isotopic composition of branched tetraether membrane lipids in a loess-paleosol sequence and its geochemical significance. Palaeogeography, Palaeoclimatology, Palaeoecology 504, 150-155. isotopes of organic matter have been widely used in quantitative reconstruction of paleovegetation and paleoclimate since they are sensitive to vegetation and environmental changes. However, the effect of transformation of soil organic matter after burial remains unclear. The carbon isotopes of brGDGTs, which were likely produced by heterotrophic bacteria in soil or peat, provide an opportunity to fill this gap. In this study, we investigated the stable carbon isotopic composition of brGDGT-derived alkane spanning the last 60?kyr in the Lantian loess-paleosol sequence from the southern Chinese Loess Plateau, as well as its relationship with δ13C values of total organic carbon (TOC) and other established climatic proxies. The results show that the δ13C values of brGDGTs were slightly depleted (ca. 1–2‰) relative to TOC, and a good linear relationship between them was observed. These support a heterotrophic lifestyle of brGDGT-producing bacteria and suggest that δ13C values of brGDGTs may have potential use in paleovegetation reconstruction. The similar variations between δ13C values of brGDGTs and TOC in the soil core also suggest that the effect of soil organic matter transformation after burial may have limited impact on the environmental significance of δ13C values of TOC. In comparison with δ13C values of the TOC, the widely used proxy for past vegetation changes, the δ13C values of brGDGTs seem more specific and sensitive in the Lantian profile due to its specific origin and stable chemical structure.Lu, S., Li, J., Zhang, P., Xue, H., Wang, G., Zhang, J., Liu, H., Li, Z., 2018. Classification of microscopic pore-throats and the grading evaluation on shale oil reservoirs. Petroleum Exploration and Development 45, 452-460. the basis of the characterization of microscopic pore-throats in shale oil reservoirs by high-pressure mercury intrusion technique, a grading evaluation standard of shale oil reservoirs and a lower limit for reservoir formation were established. Simultaneously, a new method for the classification of shale oil flow units based on logging data was established. A new classification scheme for shale oil reservoirs was proposed according to the inflection points and fractal features of mercury injection curves: microscopic pore-throats (less than 25 nm), small pore-throats (25?100 nm), medium pore-throats (100?1 000 nm) and big pore-throats (greater than 1 000 nm). Correspondingly, the shale reservoirs are divided into four classes, I, II, III and IV according to the number of microscopic pores they contain, and the average pore-throat radii corresponding to the dividing points are 150 nm, 70 nm and 10 nm respectively. By using the correlation between permeability and pore-throat radius, the permeability thresholds for the reservoir classification are determined at 1.00× 10?3 μm2, 0.40×10?3 μm2 and 0.05×10?3 μm2 respectively. By using the exponential relationship between porosity and permeability of the same hydrodynamic flow unit, a new method was set up to evaluate the reservoir flow belt index and to identify shale oil flow units with logging data. The application in the Dongying sag shows that the standard proposed is suitable for grading evaluation of shale oil reservoirs.Lu, X., Zhou, Y., Zhuang, Q., Prigent, C., Liu, Y., Teuling, A., 2018. Increasing methane emissions from natural land ecosystems due to sea‐level rise. Journal of Geophysical Research: Biogeosciences 123, 1756-1768. Atmospheric methane (CH4) is one of the most important greenhouse gases. However, there is still a large uncertainty in simulating CH4 emissions from terrestrial ecosystems. Different from modeling studies focusing on response of CH4 emissions to various environmental changes in land ecosystems, this study analyzed the response of CH4emissions to sea?level rise (SLR). To do so, a large?scale surface water routing module was incorporated into an existing CH4 model. This allowed the model to simulate the effect of SLR on river flows and inland water levels. This study focused on these freshwater systems and did not address saltwater intrusion or coastal wetland impacts. Both the annual maximum inundation extent and CH4 emissions at the global level showed a steadily growing trend, with an increase of 1.21?x?105?km2 in extent and an increase of 3.13?Tg CH4/year in CH4 emissions, in a 22-year SLR experiment from 1993 to 2014. Most of new inundation and methane source areas were located near rivers' deltas and along downstream reaches of rivers. The increase in the inundation extent is primarily influenced by precipitation, channel geomorphic characteristics, and topography of riverside area. The increase of CH4 emissions due to the SLR is largely determined by the inundation extent, but other factors such as air temperature and carbon storage also play roles. Although the current SLR-induced increases in the inundation extent and CH4 emissions only accounted for 1.0% and 1.3% of their global totals, these increases contributed 7.0% and 17.3% of the mean annual variability in both, respectively, during the study period. Considering that SLR has a long?term increasing trend, future SLR under a changing climate could play a more important role in global CH4 emissions.Lumibao, C.Y., Formel, S., Elango, V., Pardue, J.H., Blum, M., Van Bael, S.A., 2018. Persisting responses of salt marsh fungal communities to the Deepwater Horizon oil spill. Science of The Total Environment 642, 904-913. plant microbiome, composed of diverse interacting microorganisms, is thought to undergird host integrity and well-being. Though it is well understood that environmental perturbations like oil pollution can alter the diversity and composition of microbiomes, remarkably little is known about how disturbance alters plant-fungal associations. Using Next-Generation sequencing of the 18S rDNA internal transcribed spacer (ITS1) region, we examined outcomes of enduring oil exposure on aboveground leaf and belowground endophytic root and rhizosphere fungal communities of Spartina alterniflora, a highly valued ecosystem engineer in southeastern Louisiana marshes affected by the 2010 Deepwater Horizon accident. We found that aboveground foliar fungal communities exhibited site-dependent compositional turnover with consequent loss in diversity according to oiling history. Rhizosphere soil communities also exhibited shifts in community composition associated with oiling history, whereas root endophytic communities did not. Oiling did not increase or decrease similarities among aboveground and belowground communities within an individual host, indicating that host plant characteristics exert stronger control than external factors on fungal community composition. These results show that fungal community responses to oiling vary within tissues of the same host plant, and that differences in the local environment, or alternatively, site-specific differences in residual oil constrain the magnitude of exposure responses. Our study offers novel perspectives on how environmental contaminants and perturbations can influence plant microbiomes, highlighting the importance of assessing long-term ecological outcomes of oil pollution to better understand how shifts in microbial communities influence plant performance and ecosystem function. Our findings are relevant to coastal management programs tasked with responding to oil spills and increasing pressures arising from intensifying development and climate change. Understanding how modification of plant-microbiome associations influences plant performance, particularly of ecosystem engineers like S. alterniflora, can help guide efforts to protect and restore at-risk coastal ecosystems.Luo, H., Zhang, Y., Fan, W., Nan, G., Li, Z., 2018. Effects of the non-ionic surfactant (CiPOj) on the interfacial tension behavior between CO2 and crude oil. Energy & Fuels 32, 6708-6712. interfacial tension (IFT) between CO2 and crude oil is considered as one of the key properties for the CO2 flooding process, and a reduction in IFT is desirable to improve the efficiency of the process. In this work, propoxylated surfactants denoted as CiPOj (where Ci is the hydrocarbon tail and POj are oxypropylene groups, with i = 12 and j = 4–9) were adopted to reduce the IFT between CO2 and crude oil by means of the pendant drop method. The results reveal that the IFT was significantly reduced or even close to zero and the miscible phenomenon was observed in the presence of CiPOj. In comparison to pentane or ethanol, CiPOj at a dosage of 0.5 wt % causes far higher reduction of the IFT than 20 wt % pentane or 5 wt % ethanol. With the increase of the CiPOj dosage, the IFT was reduced and the slope of IFT versus pressure was increased. However, there is a threshold dosage; further addition of CiPOj beyond the threshold could no longer reduce the IFT. Moreover, attributed to the amphiphilic characteristic of CiPOj, the minimum miscibility pressure (MMP) and the first-contact miscibility pressures (Pmax) of the crude oil/CO2 systems were decreased from 19.1 and 43.0 to 13.8 and 19.0 MPa at CiPOj dosage of 0.6 wt % and temperature of 333 K, respectively.Luo, Q., Wang, Y., Wang, Y., Chen, M., Zheng, Y., Wu, S., Chang, X., Zeng, R., 2018. Time-lapse VSP monitoring for CO2 injection: A case study in ordos, China. International Journal of Greenhouse Gas Control 75, 41-51. dioxide capture and storage (CCS) is considered one of the options for reducing atmospheric emissions of CO2 from human activities. Geological storage, as an important method to reduce CO2 emissions, may lead to a series of geomechanical problems due to the large amounts of gas injected. Starting in 2010, the Shenhua CCS demonstration project in the Ordos Basin, China, which is the first and the largest full-chain saline aquifer storage project in Asia, had injected a total of 0.3 million tons (Mt) of CO2 by 2015. The VSP method was used to monitor seismic properties. Baseline and repeat VSP surveys were conducted in May 2011 and August 2013, respectively. This paper focuses on the techniques of wave field separation and consistency processing. The upgoing P wave was used to image the time-lapse profiles by the VSP-CDP stack. Comparing the results, it was found that the time-lapse VSP method provides accurate and high-resolution images to monitor the CO2 diffusion range. The reliability of the method was then checked by the lithology of the target layer. With this current time-lapse VSP and geological analysis, the results showed that there is no obvious danger of gas leakage in the project, and that CO2 has been sealed in five predetermined reservoirs.Lupisella, M.L., Race, M.S., 2018. Low-latency teleoperations, planetary protection, and astrobiology. International Journal of Astrobiology 17, 239-246. remote operation of an asset with time-delays short enough to allow for ‘real-time’ or near real-time control – often referred to as low-latency teleoperations (LLT) – has important potential to address planetary protection concerns and to enhance astrobiology exploration. Not only can LLT assist with the search for extraterrestrial life and help mitigate planetary protection concerns as required by international treaty, but it can also aid in the real-time exploration of hazardous areas, robotically manipulate samples in real-time, and engage in precise measurements and experiments without the presence of crew in the immediate area. Furthermore, LLT can be particularly effective for studying ‘Special Regions’ – areas of astrobiological interest that might be adversely affected by forward contamination from humans or spacecraft contaminants during activities on Mars. LLT can also aid human exploration by addressing concerns about backward contamination that could impact mission details for returning Martian samples and crew back to Earth.This paper provides an overview of LLT operational considerations and findings from recent NASA analyses and workshops related to planetary protection and human missions beyond Earth orbit. The paper focuses primarily on three interrelated areas of Mars operations that are particularly relevant to the planetary protection and the search for life: Mars orbit-to-surface LLT activities; Crew-on-surface and drilling LLT; and Mars surface science laboratory LLT. The paper also discusses several additional mission implementation considerations and closes with information on key knowledge gaps identified as necessary for the advance of LLT for planetary protection and astrobiology purposes on future human missions to Mars.Maaten, B., Pikkor, H., Konist, A., Siirde, A., 2018. Determination of the total sulphur content of oil shale by using different analytical methods. Oil Shale 35, 144–153. paper presents the results of determination of the total sulphur content of Estonian and Chinese oil shales (OS) by using different analytical methods – elemental analysis, quantitative chemical analysis and X-ray fluorescence spectroscopy (XRF). The different forms of sulphur and respective quantities were determined in order to offer a possible explanation to the discrepancy between the results. Thermogravimetric analysis coupled with mass spectrometry (TGA-MS) was used as an additional tool to verify the release of SO2 and confirm the existence of sulphur in the organic and mineral parts of oil shale. Different analysis methods established different sulphur contents for the samples, showing a strong relationship between the sample composition and the analysis result. For both Estonian and Chinese oil shales the highest total sulphur content values, 1.53 and 2.23%, respectively, were determined using elemental analysis. As expected, the values were highly dependent on analysis conditions: the mass of sample and amount of catalyst used. The total sulphur contents of Estonian and Chinese oil shale samples as determined by the quantitative chemical analysis were 1.2 and 2.01%, respectively. Surprisingly, for Chinese oil shale the total sulphur content found by the quantitative chemical analysis was lower than that established by XRF. XRF determined the total sulphur contents of Estonian and Chinese oil shales to be 1.2 and 2.19%, respectively. These results suggest that elemental analysis should be the preferred method for the determination of total sulphur content.MacLeod, K.G., Quinton, P.C., Sepúlveda, J., Negra, M.H., 2018. Postimpact earliest Paleogene warming shown by fish debris oxygen isotopes (El Kef, Tunisia). Science 360, 1467-1469.: Greenhouse warming is a predicted consequence of the Chicxulub impact, but supporting data are sparse. This shortcoming compromises understanding of the impact’s effects, and it has persisted due to an absence of sections that both contain suitable material for traditional carbonate- or organic-based paleothermometry and are complete and expanded enough to resolve changes on short time scales. We address the problem by analyzing the oxygen isotopic composition of fish debris, phosphatic microfossils that are relatively resistant to diagenetic alteration, from the Global Stratotype Section and Point for the Cretaceous/Paleogene boundary at El Kef, Tunisia. We report an ~1 per mil decrease in oxygen isotopic values (~5°C warming) beginning at the boundary and spanning ~300 centimeters of section (~100,000 years). The pattern found matches expectations for impact-initiated greenhouse warming.Editor's Summary: Warming after the big one. The Chicxulub impact 65 million years ago, which caused the mass extinction at the Cretaceous-Paleogene boundary, also initiated a long period of strong global warming. Using data from phosphatic microfossils, including fish teeth, scales, and bone, MacLeod et al. estimated global average temperature. Immediately after the asteroid strike, temperatures increased by ～5°C and remained high for about 100,000 years (see the Perspective by Lécuyer). These results are relevant to current climate projections, because the Chicxulub impact perturbed Earth systems on time scales even shorter than the current rate of change.Madhi, M., Kharrat, R., Hamoule, T., 2018. Screening of inhibitors for remediation of asphaltene deposits: Experimental and modeling study. Petroleum 4, 168-177. of the most severe problems during production from heavy crude oil reservoirs is the formation of asphaltene precipitation and as a result deposition in the tubing, surface facilities and near wellbore region which causes oil production and permeability reduction in addition to rock wettability alteration in the reservoir. So one of the economical ways to prevent such incidents is using the chemicals which are called asphaltene inhibitor.In this study, the influence of three commercial inhibitors, namely; Cetyl Terimethyl Ammonium Bromide (CTAB), Sodium Dodecyl Sulfate (SDS), Triton X-100 and four non-commercial (Benzene, Benzoic Acid, Salicylic Acid, Naphthalene) inhibitors on two Iranian crude oils were investigated. This study extends previous works and contributes toward the better understanding of interactions between asphaltene and inhibitor. Effect of functional groups and structure of inhibitors on asphaltene precipitation were studied and it seems clear that the nature and polarity of asphaltene (structure and amount of impurities presented) has a significant impact on the selection of inhibitors. asphaltene dispersant tests and Core flood tests were designed for evaluation of inhibitors in static and dynamic conditions. The results revealed distinguished mechanisms for asphaltene solubilization/dispersion (such as hydrogen bonding, π–π interaction and acid-base interaction) and influence of additional side group (OH) on inhibition power of inhibitor.During the experiments, it was found that increasing inhibitor concentration may lead to the self-assembly of inhibitor and declining of asphaltene stabilization. So, finding optimum concentration of inhibitor with high efficiency and available at a reasonable price is very important. The results suggest that 600 ppm of CTAB and 300 ppm of SDS were approximately optimum concentrations for the studied crude oils. One of the most important findings that differ from previous studies is the revelation of the mechanism behind the SDS/asphaltene behavior in various concentrations of inhibitor. Effect of chosen inhibitors on asphaltene precipitation and consequently deposition in porous media was studied, and then experimental data were modeled for evaluation of permeability impairment mechanisms. Permeability revived after inhibitor squeezing and cake formation mechanism played an important role in permeability reduction before and after treatment in porous media. The findings can also be applied to prediction of future behavior of reservoirs in oil field scale and evaluation of formation damage in the different period of production if needed any treatment process.Madof, A.S., 2018. Gas hydrates in coarse-grained reservoirs interpreted from velocity pull up: Mississippi Fan, Gulf of Mexico. Geology 46, 559-562. hydrates are recognized as an emerging energy resource and a submarine geohazard; they are also thought to be a modulating mechanism on the global organic carbon budget and on past climate change. Although identified primarily from reflectivity changes at the base of the stability zone, gas hydrates located above this boundary are regularly difficult to interpret, suggesting that the deposits may be present in areas previously unconsidered. Here, I introduce a nonreflectivity, traveltime-based method to detect gas hydrates in coarse-grained reservoirs. The technique uses seismic traveltime deficits located below high-velocity deposits to identify gas hydrate accumulations and magnitudes of velocity pull up to quantify in situ saturation. The approach has been applied to a portion of the central Gulf of Mexico and has uncovered continuous high-velocity accumulations contained within coarse-grained turbidites of the Quaternary Mississippi Fan. Deposits extend more than 175 km and are interpreted to be previously unidentified gas hydrate accumulations locally reaching saturations of &gt;60%. Further application of the velocity pull-up method can help to identify and quantify remaining gas hydrate reservoirs, and to aid in the worldwide assessment of the deposits as a future energy resource.Maillard, J., Carrasco, N., Schmitz-Afonso, I., Gautier, T., Afonso, C., 2018. Comparison of soluble and insoluble organic matter in analogues of Titan's aerosols. Earth and Planetary Science Letters 495, 185-191., the biggest moon of Saturn, has a thick atmosphere which presents similarities with the one thought to be on Earth at its beginning. The study of Titan's photochemical haze is thus a precious tool in gaining knowledge of the primitive atmosphere of Earth. The chemistry occurring in Titan's atmosphere and the exact processes at act in the formation of the hazes remain largely unknown. The production of analogs samples on Earth has proved to be a useful tool to improve our knowledge of the aerosols formation on Titan. Such solid organic analogs samples, named tholins, were produced with the PAMPRE experiment (French acronym for Aerosols Microgravity Production by Reactive Plasma). PAMPRE tholins were found to be mostly insoluble, with only one-third of the bulk sample that can be dissolved in methanol. This partial solubility limited the previous studies in mass spectrometry, which were done only on the soluble fraction. The goal of the present study is to compare the two fractions of PAMPRE's tholins (insoluble and soluble) using a ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometer (FTICR) equipped with a laser desorption/ionization source. Using modified Van Krevelen diagrams, we compare the global distribution of the molecules within the samples according to their Hydrogen/Carbon ratio and Nitrogen/Carbon ratio. Major differences are observed in the molecular composition of the soluble and the insoluble fraction. The soluble fraction of tholins was previously identified as a set of polymers of average formula (C2H3N)n. In this work we observe that the insoluble fraction of tholins is comprised of a significantly different set of polymers with an average composition of (C4H3N2)n.Malla, M.A., Dubey, A., Yadav, S., Kumar, A., Hashem, A., Abd Allah, E.F., 2018. Understanding and designing the strategies for the microbe-mediated remediation of environmental contaminants using omics approaches. Frontiers in Microbiology 9, :1132. doi: 1110.3389/fmicb.2018.01132. industrialization and population explosion has resulted in the generation and dumping of various contaminants into the environment. These harmful compounds deteriorate the human health as well as the surrounding environments. Current research aims to harness and enhance the natural ability of different microbes to metabolise these toxic compounds. Microbial-mediated bioremediation offers great potential to reinstate the contaminated environments in an ecologically acceptable approach. However the lack of the knowledge regarding the factors controlling and regulating the growth, metabolism and dynamics of diverse microbial communities in the contaminated environments often limits its execution. In recent years the importance of advanced tools such as genomics, proteomics, transcriptomics, metabolomics and fluxomics has increased to design the strategies to treat these contaminants in ecofriendly manner. Previously researchers has largely focused on the environmental remediation using single omics-approach, however the present review specifically addresses the integrative role of the multi-omics approaches in microbial-mediated bioremediation. Additionally, we discussed how the multi-omics approaches help to comprehend and explore the structural and functional aspects of the microbial consortia in response to the different environmental pollutants and presented some success stories by using these approaches.Mallants, D., Jeffrey, R., Zhang, X., Wu, B., Kear, J., Chen, Z., Wu, B., Bekele, E., Raiber, M., Apte, S., Gray, B., 2018. Review of plausible chemical migration pathways in Australian coal seam gas basins. International Journal of Coal Geology 195, 280-303. seam gas (CSG) or coal bed methane production has grown exponentially in Australia over the last two decades with currently nearly 7000 productive wells and another 18,750 wells planned over the next five to ten years. To address concerns over environmental contamination by hydraulic fracture fluids (HFF) attributed to (i) incidents involving poor surface handling of HFF and other fluids with potential migration pathways in soil and shallow groundwater, and (ii) leakage pathways arising from HFF injection into coal seams and unintended migration of these chemicals, the National assessment of chemicals associated with coal seam gas extraction in Australia (the Assessment) was undertaken. The Assessment included a review of international studies on unconventional gas migration pathways to provide prior knowledge and comparison for use in the Australian study. The international literature highlighted that accidents with HFF were mainly due to surface operations and included leaking equipment and spills. Contamination risks of groundwater from hydraulic fracturing itself were found to be very small based on analysis of micro-seismic and groundwater hydrochemistry data; geologic modelling of vertical fracture growth further reveals a low risk of leakage pathways developing in aquifers confined by deep shale formations. This is due to limitations on the fracture growth vertically across aquitards often hundreds of meters thick, retention within the shale of limited amounts of injected fluid, and preferential fracture growth at shallow depths in the horizontal direction. These arguments are broadly applicable to Australian CSG basins. However, important differences exist, such as the reduced thickness in Australia of the aquitards that separate the targeted gas resource from groundwater. Also, hydraulic fracturing in Australian coal seams is practised only when permeabilities are too low for gas extraction to be economical without stimulation. From the nearly 10,000 CSG wells drilled in the Bowen and Surat Basins in Queensland, only 6% have received hydraulic fracturing to date. The reduced risk of leakage pathways developing during CSG production in Australian basins is further corroborated by geologic criteria based on modelling and observations. Criteria include encountering certain favourable conditions during drilling/injection, i.e. (i) interfaces, such as natural fractures, faults, and bedding planes, which promote offsetting and branching, or rock layers with higher fracture toughness causing the cessation or reduction in fracture growth, (ii) narrow fractures due to a relatively higher elastic modulus, leading to higher viscous flow loss, (iii) high permeability layers, and (iv) overlying layer(s) with a higher confining stress. In addition to the leakage pathways considered in North American shale gas basins involving (i) pre-existing fractures and faults, or (ii) flow up the production well due to poor casing or cementing, plausible chemical migration pathways in Australian CSG basins are due to (iii) connectivity via a fracture in or extended out of the coal seam formation between CSG wells and water bores co-located in the same formation, and (iv) poor integrity water bores enhancing inter-aquifer connectivity. These plausible pathways are described and used in subsequent work as the basis of risk assessments for contamination at the local- and regional scale.Malone, K., Pesch, S., Schlüter, M., Krause, D., 2018. Oil droplet size distributions in deep-sea blowouts: Influence of pressure and dissolved gases. Environmental Science & Technology 52, 6326-6333. date, experimental investigations to determine the droplet size distribution (DSD) of subsea oil spills were mostly conducted at surface conditions, i.e. at atmospheric pressure, and with dead, i.e. purely liquid, oils. To investigate the influence of high hydrostatic pressure and of gases dissolved in the oil on the DSD, experiments with a downscaled blowout are conducted in a high-pressure autoclave at 150 bar hydrostatic pressure. Jets of “live”, i.e. methane-saturated, crude oil and n-decane are compared to jets of “dead” hydrocarbon liquids in artificial seawater. Experiments show that methane dissolved in the liquid oil increases the volume median droplet diameter significantly by up to 97%. These results are not in good accordance with state-of-the-art drop formation models, which are based on oil-only experiments at atmospheric pressure, and therefore show the need for a modification of such models which incorporates effects of hydrostatic pressure and dissolved gases for the modeling of deep-sea oil spills and blowouts.Malvoisin, B., Mazzini, A., Miller, S.A., 2018. Deep hydrothermal activity driving the Lusi mud eruption. Earth and Planetary Science Letters 497, 42-49. Lusi mud eruption in East Java continues unabated after more than a decade of activity as a pulsating geyser system bursting mud, clasts, water, and gas. The origin of the fluids and their properties at depth are not well constrained, thus hampering our understanding and modelling of the system. Previous geochemical and geophysical studies show that Lusi is a sediment-hosted hydrothermal system with two sources of mud at depths between 0.3–2 km and another between 3.5–4.75 km. Here, we present results of mineral thermometry using Raman spectroscopy and chlorite composition on clasts erupted at Lusi. The results show that some of these specimens originate from the two main fluid sources, and at depths consistent with the geochemical and geophysical interpretation. Two main clast lithotypes erupt at Lusi. The first lithotype is a light grey shale returned to the surface from the Upper Kalibeng Formation (the primary mud source) and equilibrated at temperatures below 200?°C. The second lithotype is a black shale, whose source is the Ngimbang Formation at >3800 m depth. Two distinct temperature clusters are recorded in these black shales: one at 179 ±17 °C, consistent with the temperature estimate at 3800 m depth with the pre-eruption geothermal gradient, while younger minerals in the same specimen recorded substantial anomalous heating at ～250?°C. These high temperatures indicate interaction with a heat source associated with the eruption through mixing with hydrothermal fluids. This temperature jump suggests rapid heating at ～4000 m depth, consistent with a scenario of a magmatic intrusion and hydrothermal fluids circulation. This rapid and significant temperature increase would initiate devolatilisation reactions of hydrous minerals within the deep sedimentary package and generate substantial (highly overpressured) fluids at depths significantly below the main source of erupted mud. We infer that reactive and thermal pressurisation led to a deep and metastable system susceptible to e.g. seismic activity ultimately opening fluid pathways towards the surface along the Watukosek fault system. The two temperatures clusters recorded in the clasts show that conductive heat flow was the dominant heat transport prior to the eruption, while the system is now driven by large-scale convection and advective heat transport. The Lusi eruption occurred in a highly populated area forcing the evacuation of several tens of thousands of people. This system appears unstoppable and poses a real and present hazard for the settlements still surrounding the eruption site. Continuous research is necessary to understand this spectacular phenomenon, both for its important scientific relevance, and the societal impact of this natural disaster.Mandakovic, D., Maldonado, J., Pulgar, R., Cabrera, P., Gaete, A., Urtuvia, V., Seeger, M., Cambiazo, V., González, M., 2018. Microbiome analysis and bacterial isolation from Lejía Lake soil in Atacama Desert. Extremophiles 22, 665-673. a consequence of the severe climatic change affecting our entire world, many lakes in the Andes Cordillera are likely to disappear within a few decades. One of these lakes is Lejía Lake, located in the central Atacama Desert. The objectives of this study were: (1) to characterize the bacterial community from Lejía Lake shore soil (LLS) using 16S rRNA sequencing and (2) to test a culture-based approach using a soil extract medium (SEM) to recover soil bacteria. This extreme ecosystem was dominated by three phyla: Bacteroidetes, Proteobacteria, and Firmicutes with 29.2, 28.2 and 28.1% of the relative abundance, respectively. Using SEM, we recovered 7.4% of the operational taxonomic units from LLS, all of which belonged to the same three dominant phyla from LLS (6.9% of Bacteroidetes, 77.6% of Proteobacteria, and 15.3% of Firmicutes). In addition, we used SEM to recover isolates from LLS and supplemented the culture medium with increasing salt concentrations to isolate microbial representatives of salt tolerance (Halomonas spp.). The results of this study complement the list of microbial taxa diversity from the Atacama Desert and assess a pipeline to isolate selective bacteria that could represent useful elements for biotechnological approaches.Mann, A., 2018. Life after the asteroid apocalypse. Proceedings of the National Academy of Sciences 115, 5820. million years ago, an asteroid wiped out a huge swath of life on planet Earth. Could similar impacts have helped kick-start life itself?“Wow, she’s really high above the water,” Sean Gulick thought as his ship chugged toward a drilling platform some 30 kilometers off Mexico’s Yucatan Peninsula. Perched on three sturdy pylons resting on the seafloor, the innovative platform—a “liftboat” known as Myrtle—towered 17 meters above the ocean’s surface.Researchers needed to keep Myrtle well clear of the waves to steady the drilling equipment that extended from the platform. Their efforts worked: After boring more than 1,300 meters into the seafloor, Myrtle’s crew collected hundreds of intact cores of rock from beneath the surface of the 190-kilometer-wide Chicxulub crater. “I have been on over 25 scientific cruises,” Gulick, a geoscientist at the University of Texas at Austin (UT), wrote on the mission blog during drilling operations in April 2016. “But never on one with as much potential for discovering something truly new.” What the researchers found were indications that living organisms bounced back in the face of extraordinary devastation—in the process, they may have uncovered a clue or two about life’s very beginnings.Even if most people don’t recognize its name, the Chicxulub crater is probably the most famous impact scar on the surface of our planet. The crater formed a little more than 66 million years ago when a meteorite the size of San Francisco tore through our atmosphere and plowed into Earth’s surface, ending the reign of the dinosaurs. The catastrophe wiped out 75% of all species on the planet and left behind a giant blemish that researchers have been studying for decades.The impact also left behind several longstanding mysteries. The center of the Chicxulub crater contains a circular range of hills known as a peak ring, and Gulick and his research team ventured to the Yucatan to try to understand how the ring had formed. They also hoped to reconstruct how local life had recovered after the disaster.Over the past year, analysis of the rock cores drilled out of the Earth has exceeded the team’s initial expectations and offered more than a few surprises. Although large asteroids that smash into the Earth are often regarded as destructive killers—and they are—that is only part of the story. At the crash site, the researchers discovered evidence of a productive ecosystem that thrived in the immediate aftermath of the fiery strike. “It was the opposite of what we expected,” says geophysicist and mission co-chief Joanna Morgan of Imperial College London in the United Kingdom. “It actually ended up being a habitat for life, and quite soon after the impact.”Other findings lend credence to an even more radical idea. During the first half-billion years of Earth’s history, a constant shower of impactors bombarded the planet at rates that should have rendered the surface uninhabitable. But beneath Chicxulub and other craters, researchers have uncovered fossilized hydrothermal systems created by these impacts. The systems bear a remarkable resemblance to the volcanic chimneys known as black smokers that are found in mid-oceanic ridges. “These vast subsurface hydrothermal systems would have been perfect crucibles for prebiotic chemistry,” says planetary scientist David Kring of the Lunar and Planetary Institute in Houston. Such results suggest that this early incendiary spree might have done more than rain fiery destruction on the planet. The impact’s aftermath could have helped generate the conditions necessary for the creation of life itself.Ground ZeroIn 1980, father-and-son researchers Luis and Walter Alvarez, both at the University of California, Berkeley, hypothesized that an extraterrestrial impactor precipitated the extinction event that took out the dinosaurs (1). Controversial at the time, the theory was based on a 66-million-year-old worldwide geological layer rich in iridium, an element rare on Earth but common in asteroids. The Alvarez duo eventually succeeded in convincing most of their colleagues, and about a decade later, surveyors found a likely location for ground zero of the apocalyptic event.The Mexican state-owned oil company Pemex had conducted geological forays into a region near a Yucatan town called Chicxulub in the late 1970s, hoping to find petroleum. Using data on magnetic and gravimetric anomalies in the area, researchers identified a ring-like structure at least 70 kilometers across. In 1991, they tested the oil company’s stored samples and found that they contained shocked quartz, a mineral that forms only in asteroid strikes and nuclear test sites (2). Five years later, Morgan and her colleagues blasted the seafloor with seismic waves, which bounced back and allowed them to map the full extent of the feature, which sticks out from the Yucatan Peninsula, half onshore and half off (3).Chicxulub turned out to be the third-biggest impact crater on Earth and the only one young enough to retain its central peak ring, whose jagged bulls-eye of hills once rose taller than the Eiffel Tower above the crater floor. Such structures have been spotted in large craters on Mercury, Venus, Mars, and the Moon, but nobody was quite sure which aspects of an impact were responsible for creating them. Chicxulub finally offered a chance for geologists to take a hands-on approach to these enigmatic formations. “We have access to the subsurface of Chicxulub, which we don’t have to similarly sized craters elsewhere in the solar system,” says geophysicist Jay Melosh of Purdue University in West Lafayette, IN. “There’s still no better way to learn about the craters then to actually drill in.”In 1996, Morgan approached the International Ocean Discovery Program (IODP), a global marine research collaboration funded by the governmental agencies of country members, to fund a major expedition that could collect cores from below Chicxulub. But the $100-million price tag of the proposed mission made it a nonstarter. It would take nearly two decades to gather enough additional data and support, and for Morgan to slim down the project to a tenth of its original price, before the collaboration agreed to carry out what became IODP Expedition 364.In the eons since the Chicxulub impact, the crater had been buried under a half kilometer of limestone sediments. From their perch on Myrtle, the Expedition 364 team used a diamond-tipped drill to bore through this upper layer before switching to coring bits, which only drill the sides of a hole and leave the middle untouched, creating 3-meter-long cylindrical samples of the subsurface. These segments, each a little wider than a hockey puck, provide a window into the geologic layers surrounding the crater’s peak ring.The samples didn’t come easy—life onboard the vessel was not exactly lavish. “We were living six to a cabin and working in shipping containers turned into labs,” recalls Gulick. “But we didn’t care because of the sheer excitement of discovery.” Morgan says her single most thrilling moment was when the drill reached the peak ring at a depth of around 640 meters below the seafloor and began pulling up “stunningly beautiful” granite blocks. These exquisite orange- and black-speckled samples helped the research team assess two competing theories about the likely mechanism behind peak-ring formation in craters.Dynamic CollapseOne proposal, the nested melt-cavity hypothesis, suggests that a gigantic sheet of molten rock engulfs a crater’s floor in the moments after a major meteorite impact. The rim of the crater then slumps inward, bumping up against the molten rock and forming a peak ring. In Chicxulub’s case, that ring would contain minerals from the layer of limestone that the asteroid originally burrowed through.But the core samples support a different theory, known as the dynamic collapse model. It posits that the powerful meteorite blast dug a hole 30 kilometers deep and exposed the rocks beneath to nearly 600,000 times normal atmospheric pressure. For roughly 10 minutes, the ground at the impact site behaved like a viscous fluid, rebounding upward to create a dramatic cascade of debris that fell back and formed the ring-shaped structure. Expedition 364 found granite in the peak ring that originally came from 8–10 kilometers below the surface, heavily favoring this idea (4).The result was unexpected, says Melosh. Earlier studies that involved bouncing seismic waves off the crater’s subsurface had suggested it contained rocks with the density of sedimentary minerals such as limestone. But the granite core samples extracted by Myrtle had been so pulverized and fractured by the meteorite impact that their density was lower than normal granite and similar to a sedimentary rock. “To this day we don’t understand what the pattern of fractures was that led to those changes,” Melosh says.Just as puzzling are the relatively ephemeral effects on the surrounding ecosystem—gleaned from discoveries at Chicxulub that stand in marked contrast to previous findings. Sitting below the Chesapeake Bay in Virginia is another crater, which is both smaller—only 85 kilometers across—and about 30 million years younger than Chicxulub; it is the only other relatively large marine crater whose ancient ecological impact has been explored. Researchers with the US Geological Survey have drilled into the Chesapeake Bay crater and uncovered evidence that the impact caused a 4,000-year-long dead zone on the ocean floor and that marine life in the area took nearly 1 million years to recover its full productivity and diversity (5).Because Chicxulub is a larger crater, with a stronger environmental impact, “we expected that we would see something worse,” says micropaleontologist Christopher Lowery, also at UT. But instead, the group’s data revealed that the ecological upheaval from the Chicxulub impactor passed much more quickly. The question was: What made Chicxulub’s aftermath so drastically different?Death and DestructionThe days after that fateful asteroid strike must have been truly devastating. Smashing into the Gulf of Mexico, the 10- to-15-kilometer-wide bolide generated tsunamis 100 meters high that battered the Caribbean islands and southeastern United States, leaving geologic indications of their destruction as far inland as central Texas (6). Charcoal deposits indicate that global forest fires might have raged for months (7). Sulfur-rich aerosols vaporized by the asteroid blast lingered in the atmosphere and blotted out the Sun, starving photosynthetic organisms and causing worldwide temperatures to plunge by an average of 26??C for a decade and a half (8).In the aftermath of Chicxulub, 90% of Foraminifera species—tiny amoeba-like creatures that produce incredible geometric shells—went extinct around the world. Yet the Expedition 364 cores of sediment layers from just above the crater contain a surprisingly rich diversity of Foraminifera microfossils. Trace fossils, which were left by animals such as worms and small crustaceans burrowing in the seafloor, also appeared rapidly after the event. Geochemical analyses of the samples suggested that large amounts of biomass were being generated in the area just 30,000 years after the cataclysm.Nevertheless, the ecosystem at Chicxulub was clearly turned upside down by the blast. Photosynthetic phytoplankton struggled to recover for millions of years after the event, for example. Samples from the expedition suggested that there was an order of magnitude less diversity in phytoplankton fossils than in zooplankton such as Foraminifera, which typically feed on phytoplankton. The research team is still puzzling over the difference in these rates of recovery and what the Foraminifera were living on during this period. “It’s counterintuitive,” says earth scientist Timothy Bralower of Pennsylvania State University in University Park, PA, who is studying the phytoplankton fossils.Part of the answer may lie in the physical landscape surrounding Chicxulub. When the Chesapeake Bay meteorite struck the ground, it carved out a shallow depression that isolated water inside the crater from the rest of the Atlantic Ocean. In contrast, Chicxulub’s tsunamis traveled to the edges of the Gulf of Mexico and then reflected back, filling the crater and rapidly reconnecting it to the larger ocean.Core samples recovered by Expedition 364 also revealed that porous rocks in the center of the Chicxulub crater had remained hotter than 300?°C for more than 100,000 years. Seawater percolating through these “The whole of the early planet could have been a giant prebiotic reactor.”—Charles Cockellrocks would have created an ecosystem analogous to underwater volcanoes that belch mineral-rich water and feed microbes. Although similar structures appeared in the Chesapeake Bay, the water within that crater was stagnant and unable to draw in nutrients from the larger ocean. Lowery speculates that the hydrothermal environment at Chicxulub might have helped nurture the organisms nearby, allowing the productivity of some species to recover much more quickly.Crucibles of LifeThese findings dovetail nicely with a theory that Kring has long advocated, called the impact-origin of life hypothesis. This suggests that asteroid strikes might have provided a jolt of energy that stirred up biochemistry and ignited the process of creating living organisms (9). “Just like around Yellowstone today, you would have had circulating hot water systems,” says Kring. “And we know from Yellowstone that some very primitive life can persist in those types of environments.”There are indications that the Earth was already water-rich a mere 100 million years after it coalesced from a ring of dust around the early Sun (10). Leftover chunks from the solar system’s genesis would have been slamming into the primordial planet around this time, potentially generating energy-rich environments that could persist for millions of years after each crash.“The whole of the early planet could have been a giant prebiotic reactor,” says astrobiologist Charles Cockell of the University of Edinburgh in the United Kingdom. Craters might have made particularly good crucibles, he adds, because they would contain heat gradients that slowly cooled, favoring the creation of different types of organic molecules at different times. “You can see impacts as generating a whole set of experiments, producing lots of organic material, and then at some point you can imagine that a self-replicating molecule emerged.”Geneticists have suggested that the earliest common ancestor to all organisms on Earth might have been a hyperthermophile—an extreme heat lover—providing further evidence that the organic Garden of Eden could have been forged by a meteorite (11). Still, the idea has a long way to go before gaining widespread acceptance.“As we scientists like to say, ‘It is not unreasonable’,” muses planetary scientist Kevin Zahnle of NASA’s Ames Research Center in Moffett Field, CA. But it is difficult to say whether impacts are better bets for life’s origins compared with alternatives such as volcanic hydrothermal vents, he adds.“I think it’s a real mistake for anyone to get too polarized about pet environments,” agrees Cockell. “It was a sheer random event that a molecule emerged that happened to be able to self-replicate. Maybe there are lots of environments where that could happen.”For now, says Kring, the Chicxulub results suggest that the hydrothermal system created by the impact was sufficiently hot and long-lived to favor biochemical experimentation and nurture living organisms. More details about Earth’s earliest days, along with information from the Moon’s well-preserved geologic record, will be necessary to test his hypothesis further.In either case, the findings coming from Chicxulub continue to astound and bewilder, exposing more layers in this famous story. “I often say that asteroid impacts both giveth and taketh away,” says Melosh. “That’s very much what Chicxulub did. It wiped out the biota at the time, but then set the stage for the recovery of mammals to take over the Earth.”References1. Alvarez LW, Alvarez W, Asaro F, Michel HV (1980) Extraterrestrial cause for the cretaceous-tertiary extinction. Science 208:1095–1108..2. Hildebrand A, et al. (1991) Chicxulub crater: A possible Cretaceous/Tertiary boundary impact crater on the Yucatán Peninsula, Mexico. Geology 19:867–871.3. Morgan J, et al. (1997) Size and morphology of the Chicxulub impact crater. Nature 390:472–476..4. Morgan JV, et al. (2016) The formation of peak rings in large impact craters. Science 354:878–882..5. Poag CW, et al. (2004) The Chesapeake Bay Crater (Springer, Berlin), pp 387–432..6. Hart M, et al. (2013) The Cretaceous-Paleogene boundary on the Brazos River, Texas: New stratigraphic sections and revised interpretations. GCAGS J 1:69–80.7. Wolbach WS, Gilmour I, Anders E (1990) Major wildfires at the Cretaceous/Tertiary boundary. Global Catastrophes in Earth History: An Interdisciplinary Conference on Impacts, Volcanism, and Mass Mortality, eds Sharpton VL, Ward PD (Geological Society of America, Boulder, CO), Vol 247, pp 247–391.8. Artemieva N, et al. (2017) Quantifying the release of climate-active gases by large meteorite impacts with a case study of Chicxulub. Geophys Res Lett 44:10180–10188.9. Kring D (2000) Impact events and their effect on the origin, evolution, and distribution of life. GSA Today 10:1–7.10. Wilde SA, Valley JW, Peck WH, Graham CM (2001) Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago. Nature 409:175–178.11. Stetter KO (2006) Hyperthermophiles in the history of life. Philos Trans R Soc Lond B Biol Sci 361:1837–1842, discussion 1842–1843.Manzoni, S., ?apek, P., Porada, P., Thurner, M., Winterdahl, M., Beer, C., Brüchert, V., Frouz, J., Herrmann, A.M., Lindahl, B.D., Lyon, S.W., ?antr??ková, H., Vico, G., Way, D., 2018. Reviews and syntheses: Carbon use efficiency from organisms to ecosystems – Definitions, theories, and empirical evidence. Biogeosciences Discussions 2018, 1-29. cycling of carbon (C) between the Earth surface and the atmosphere is controlled by biological and abiotic processes that regulate C storage in biogeochemical compartments and release to the atmosphere. This partitioning is quantified using various forms of C-use efficiency (CUE) – the ratio of C remaining in a system over C entering that system. Biological CUE is the fraction of C taken up allocated to new biomass. In soils and sediments C storage depends also on abiotic processes, so the term C-storage efficiency (CSE) can be used. Here we first review and reconcile CUE and CSE definitions proposed for autotrophic and heterotrophic organisms and communities, food webs, whole ecosystems, and soils and sediments using a common mathematical framework. Second, we identify general CUE patterns, such as the CUE increase with improving growing conditions, and apparent decrease due to turnover. We then synthesize >?6000 CUE estimates showing that CUE decreases with increasing biological and ecological organization – from unicellular to multicellular organisms, and from individuals to ecosystems. We conclude that CUE is an emergent property of coupled biological-abiotic systems, and it should be regarded as a flexible and scale-dependent index of the capacity of a given system to effectively retain C.Marques, C.R., 2018. Extremophilic microfactories: Applications in metal and radionuclide bioremediation. Frontiers in Microbiology 9, 1191. doi: 1110.3389/fmicb.2018.01191. and radionuclides (M&Rs) are a worldwide concern claiming for resilient, efficient and sustainable clean-up measures aligned with environmental protection goals and global change constraints. The unique defense mechanisms of extremophilic bacteria and archaea have been proving usefulness towards M&Rs bioremediation. Hence, extremophiles can be viewed as microfactories capable of providing specific and controlled services (i.e., genetic/metabolic mechanisms) and/or products (e.g., biomolecules) for that purpose. However, the natural physiological plasticity of such extremophilic microfactories can be further explored to nourish different hallmarks of M&R bioremediation, which are scantly approached in the literature and were never integrated. Therefore, this review not only briefly describes major valuable extremophilic pathways for M&R bioremediation, as it highlights the advances, challenges and gaps from the interplay of ‘omics’ and biological engineering to improve extremophilic microfactories performance for M&R clean-up. Microfactories’ potentialities are also envisaged to close the M&R bioremediation processes and shift the classical idea of never ‘getting rid’ of M&Rs into making them ‘the belle of the ball’ through bio-recycling and bio-recovering techniques.Maruyama, S., Santosh, M., Azuma, S., 2018. Initiation of plate tectonics in the Hadean: Eclogitization triggered by the ABEL Bombardment. Geoscience Frontiers 9, 1033-1048. plate tectonics began on the Earth has been long debated and here we argue this topic based on the records of Earth-Moon geology and asteroid belt to conclude that the onset of plate tectonics was during the middle Hadean (4.37–4.20?Ga). The trigger of the initiation of plate tectonics is the ABEL Bombardment, which delivered oceanic and atmospheric components on a completely dry reductive Earth, originally comprised of enstatite chondrite-like materials. Through the accretion of volatiles, shock metamorphism processed with vaporization of both CI chondrite and supracrustal rocks at the bombarded location, and significant recrystallization went through under wet conditions, caused considerable eclogitization in the primordial continents composed of felsic upper crust of 21?km thick anorthosite, and 50?km or even thicker KREEP lower crust. Eclogitization must have yielded a powerful slab-pull force to initiate plate tectonics in the middle Hadean. Another important factor is the size of the bombardment. By creating Pacific Ocean class crater by 1000?km across impactor, rigid plate operating stagnant lid tectonics since the early Hadean was severely destroyed, and oceanic lithosphere was generated to have bi-modal lithosphere on the Earth to enable the operation of plate tectonics. Considering the importance of the ABEL Bombardment event which initiated plate tectonics including the appearance of ocean and atmosphere, we propose that the Hadean Eon can be subdivided into three?periods: (1) early Hadean (4.57–4.37?Ga), (2) middle Hadean (4.37–4.20?Ga), and (3) late Hadean (4.20–4.00?Ga).Masaki, Y., Hirajima, T., Sasaki, K., Miki, H., Okibe, N., 2018. Microbiological redox potential control to improve the efficiency of chalcopyrite bioleaching. Geomicrobiology Journal 35, 648-656. effect of controlling the redox potential (Eh) on chalcopyrite bioleaching kinetics was studied as a new aspect of redox control during chalcopyrite bioleaching, and its mechanism was investigated by employing the “normalized” solution redox potential (Enormal) and the reaction kinetics model. Different Eh ranges were established by use of different acidophiles (Sulfobacillus acidophilus YTF1; Sulfobacillus sibiricus N1; Acidimicrobium ferrooxidans ICP; Acidiplasma sp. Fv-AP). Cu dissolution was very susceptible to real-time change in Eh during the reaction. It was found that efficiency of bioleaching of chalcopyrite can be effectively evaluated on the basis of Enormal, since it is normalized for real-time fluctuations of concentrations of major metal solutes during bioleaching. For steady Cu solubilization during bioleaching at a maximum rate, it was important to maintain a redox potential range of 0 ≤ Enormal ≤ 1 (?0.35 mV optimal) at the mineral surface by employing a “weak” ion-oxidizer. This led to a copper recovery of > 75%. At higher Enormal levels ( Enormal > 1 by “strong” microbial Fe2+ oxidation), Cu solubilization was slowed by diffusion through the product film at the mineral surface (< 50% Cu recovery) caused by low reactivity of the chalcopyrite and by secondary passivation of the chalcopyrite surface, mainly by jarosite.Mastalerz, M., Drobniak, A., Stankiewicz, A.B., 2018. Origin, properties, and implications of solid bitumen in source-rock reservoirs: A review. International Journal of Coal Geology 195, 14-36. paper reviews the significance of solid bitumen with emphasis on source-rock reservoirs. We discuss difficulties and discrepancies with terminology, especially those terms related to the origin of solid bitumen and its physical and chemical properties. Various definitions of solid bitumen have their own justifications and can be used provided there is clarity about which defining criteria are being considered. Difficulties in conforming to chemical-, solubility-, or origin-related definitions lead us to suggest adapting the reflectance of solid hydrocarbon as a practical choice for placing the boundary between solid bitumen and pyrobitumen, and 1.50% is proposed as the boundary value. It has to be noted that this boundary may be shifted down to 1.3% for sulfur-rich kerogen. Recently, much progress has been made by combining imaging and physical adsorption techniques in porosity studies, and so the porosity of solid bitumen is given special emphasis. Comparing pore characteristics obtained from SEM versus those generated by gas adsorption, mercury intrusion, or neutron scattering techniques indicates that the SEM pore inventory fails to account for the smallest pores (<5?nm in size) present in organic matter. Therefore, low-pressure CO2 adsorption is still the most effective technique to assess microporosity (pores <2?nm in diameter) in shales. We conclude that combining observational in situ techniques with techniques based on physical principles is necessary to make progress toward a better understanding of porosity systems in organic matter, including solid bitumen.We review the implications of the abundance of solid bitumen on reservoir quality, porosity, permeability, and producibility, based on examples of selected sequences. One of the difficulties in predicting the influence of solid-bitumen-bearing horizons on reservoir quality arises from the problems with detecting organic phases using various logging techniques. The use of specialized techniques such as NMR logging that allows two-dimensional T1 and T2 measurements should be expanded, and other potential techniques need to be further researched and tested. Certain aspects of the properties of solid bitumen that are not as well understood, such as its hydrocarbon generation potential or its role in hydrocarbon migration are also discussed with the aim of identifying further research that could lead to a better understanding of the role that solid bitumen plays in unconventional reservoirs.Mastrogiuseppe, M., Poggiali, V., Hayes, A.G., Lunine, J.I., Seu, R., Di Achille, G., Lorenz, R.D., 2018. Cassini radar observation of Punga Mare and environs: Bathymetry and composition. Earth and Planetary Science Letters 496, 89-95. January 2015 (fly-by T108), the Cassini radar observed Punga Mare, Titan's northernmost and third-largest sea, in altimetry mode during closest approach. The ground track intercepted a section of the mare and a system of channels and flooded areas connecting Punga to Kraken Mare. We use a processing technique, successfully adopted for Ligeia Mare and Ontario Lacus, for detecting echoes from the sea floor and constraining the depth and composition of these liquid bodies. We find that, along the radar transect, Punga Mare has a maximum measured depth of 110 m. The relative reduction in backscatter of the seafloor, as a function of increasing depth, suggests a liquid loss tangent of 3 ± 1 × 10 ? 5 . While this value is within the formal uncertainty of the loss tangent derived for Ligeia Mare, the best-fit solution is lower and is consistent with a nearly pure binary methane-nitrogen liquid with little to no ethane or higher order components. The indication of very low amounts of ethane toward the pole suggests that atmospheric processes are controlling the surface liquid composition of Titan's seas.Matheus Carnevali, P.B., Herbold, C.W., Hand, K.P., Priscu, J.C., Murray, A.E., 2018. Distinct microbial assemblage structure and archaeal diversity in sediments of Arctic thermokarst lakes differing in methane sources. Frontiers in Microbiology 9, 1192. doi: 1110.3389/fmicb.2018.01192. an ecological understanding of Arctic thermokarst lake sediment-associated microbial diversity, distributions, and potential activities in a geochemical context is an essential first step towards comprehending the contributions of these systems to greenhouse gas emissions, and understanding how they may shift as a result of long term changes in climate. In light of this, we set out to study microbial diversity and structure in sediments from four shallow thermokarst lakes in the Arctic Coastal Plain of Alaska. Sediments from one of these lakes (Sukok) emit methane (CH4) of thermogenic origin, as expected for an area with natural gas reserves. However, sediments from a lake 10 km to the North West (Siqlukaq) produce CH4 of biogenic origin. Sukok and Siqlukaq were chosen among the four lakes surveyed to test the hypothesis that active CH4-producing organisms (methanogens) would reflect the distribution of CH4 gas levels in the sediments. We first examined the structure of the little known microbial community inhabiting the thaw bulb of arctic thermokarst lakes near Barrow, AK. Molecular approaches (PCR-DGGE and iTag sequencing) targeting the SSU rRNA gene and rRNA molecule were used to profile diversity, assemblage structure, and identify potentially active members of the microbial assemblages. Overall, the potentially active (rRNA dominant) fraction included taxa that have also been detected in other permafrost environments (e.g. Bacteroidetes, Actinobacteria, Nitrospirae, Chloroflexi and others). In addition, Siqlukaq sediments were unique compared to the other sites, in that they harbored CH4-cycling organisms (i.e. methanogenic Archaea and methanotrophic Bacteria), as well as bacteria potentially involved in N cycling (e.g. Nitrospirae) whereas Sukok sediments were dominated by taxa typically involved in photosynthesis and biogeochemical sulfur (S) transformations. This study revealed a high degree of archaeal phylogenetic diversity in addition to CH4-producing archaea, which spanned nearly the phylogenetic extent of currently recognized Archaea phyla (e.g. Euryarchaeota, Bathyarchaeota, Thaumarchaeota, Woesearchaeota, Pacearchaeota, and others). Together these results shed light on expansive bacterial and archaeal diversity in Arctic thermokarst lakes and suggest important differences in biogeochemical potential in contrasting methanogenic Arctic thermokarst lake sediment ecosystems.Mayer, J., Sachsenhofer, R.F., Ungureanu, C., Bechtel, A., Gratzer, R., Sweda, M., Tari, G., 2018. Petroleum charge and migration in the Black Sea: Insights from oil and source rock geochemistry. Journal of Petroleum Geology 41, 337-350. a number of significant oil and gas discoveries have been made within the Western Black Sea and the surrounding area, only sparse data about migration mechanisms are available. In this paper, biomarker and isotope data from five oilfields and one oil show located offshore Bulgaria and Romania (in the western Black Sea), and from one field onshore Georgia (at the margin of the eastern Black Sea), were compared with geochemical data from potential source rock intervals from borehole samples. The source rock data came from offshore Bulgaria and outcrop samples from onshore Georgia. The biomarker data indicates that all the oils analysed were generated by source rocks of Late Cretaceous or Cenozoic age. In the Western Black Sea sub‐basin, the most likely source rocks are Oligocene to Lower Miocene shales of the Maikop Group. Compound‐specific isotope data indicate that Lower Oligocene source rocks are the most significant although a contribution by Lower Miocene diatom‐rich source rocks cannot be excluded. For an oil sample from the Shromisubani field onshore Georgia, isotope data from individual n‐alkanes together with biomarker data indicates that the oil contains a mixture of hydrocarbons generated from the Middle Eocene Kuma Formation and the Oligocene part of the Maikop Group. Oligocene and Miocene source rocks are immature at the shelfal locations where the oil samples were recovered. Charge for these hydrocarbon accumulations is interpreted to have been provided by long‐distance lateral migration from source kitchens in more central parts of the Black Sea basin, where Oligocene and (some) Miocene source rocks are within the oil and gas window. The results of this study highlight the prospectivity of recently‐discovered deep‐water plays, and significantly de‐risk future deep‐water projects within the Black Sea area. McConnell, J.R., Wilson, A.I., Stohl, A., Arienzo, M.M., Chellman, N.J., Eckhardt, S., Thompson, E.M., Pollard, A.M., Steffensen, J.P., 2018. Lead pollution recorded in Greenland ice indicates European emissions tracked plagues, wars, and imperial expansion during antiquity. Proceedings of the National Academy of Sciences 115, 5726-5731.: An 1100 BCE to 800 CE record of estimated lead emissions based on continuous, subannually resolved, and precisely dated measurements of lead pollution in deep Greenland ice and atmospheric modeling shows that European emissions closely varied with historical events, including imperial expansion, wars, and major plagues. Emissions rose coeval with Phoenician expansion and accelerated during expanded Carthaginian and Roman lead–silver mining primarily in the Iberian Peninsula. Emissions fluctuated synchronously with wars and political instability, particularly during the Roman Republic, reaching a sustained maximum during the Roman Empire before plunging in the second century coincident with the Antonine plague, and remaining low for >500 years. Bullion in silver coinage declined in parallel, reflecting the importance of lead–silver mining in ancient economies.Abstract:An 1100 BCE to 800 CE record of estimated lead emissions based on continuous, subannually resolved, and precisely dated measurements of lead pollution in deep Greenland ice and atmospheric modeling shows that European emissions closely varied with historical events, including imperial expansion, wars, and major plagues. Emissions rose coeval with Phoenician expansion and accelerated during expanded Carthaginian and Roman lead–silver mining primarily in the Iberian Peninsula. Emissions fluctuated synchronously with wars and political instability, particularly during the Roman Republic, reaching a sustained maximum during the Roman Empire before plunging in the second century coincident with the Antonine plague, and remaining low for &amp;gt;500 years. Bullion in silver coinage declined in parallel, reflecting the importance of lead–silver mining in ancient economies.Lead pollution in Arctic ice reflects midlatitude emissions from ancient lead–silver mining and smelting. The few reported measurements have been extrapolated to infer the performance of ancient economies, including comparisons of economic productivity and growth during the Roman Republican and Imperial periods. These studies were based on sparse sampling and inaccurate dating, limiting understanding of trends and specific linkages. Here we show, using a precisely dated record of estimated lead emissions between 1100 BCE and 800 CE derived from subannually resolved measurements in Greenland ice and detailed atmospheric transport modeling, that annual European lead emissions closely varied with historical events, including imperial expansion, wars, and major plagues. Emissions rose coeval with Phoenician expansion, accelerated during expanded Carthaginian and Roman mining primarily in the Iberian Peninsula, and reached a maximum under the Roman Empire. Emissions fluctuated synchronously with wars and political instability particularly during the Roman Republic, and plunged coincident with two major plagues in the second and third centuries, remaining low for &amp;gt;500 years. Bullion in silver coinage declined in parallel, reflecting the importance of lead–silver mining in ancient economies. Our results indicate sustained economic growth during the first two centuries of the Roman Empire, terminated by the second-century Antonine plague.McFarlin, J.M., Axford, Y., Osburn, M.R., Kelly, M.A., Osterberg, E.C., Farnsworth, L.B., 2018. Pronounced summer warming in northwest Greenland during the Holocene and Last Interglacial. Proceedings of the National Academy of Sciences 115, 6357-6362.: Reconstructions of climate over Greenland during past warm periods provide crucial insights into the likely response of the Greenland Ice Sheet to future warming. However, limited preservation of interglacial archives due to extensive glacial scouring has hindered paleoclimate reconstructions along Greenland’s margins. Here, we report a Greenland lake sediment record that preserves both the present and previous interglacial periods. This record, combined with prior studies, demonstrates exceptionally strong warming over the northern Greenland Ice Sheet. Pronounced summer warming in this region helps explain ice sheet changes in the Early Holocene, while highlighting seemingly incongruous evidence for ice sheet extent and temperatures during the Last Interglacial. These findings may portend large future warming in this high-latitude region.Abstract: Reconstructions of climate over Greenland during past warm periods provide crucial insights into the likely response of the Greenland Ice Sheet to future warming. However, limited preservation of interglacial archives due to extensive glacial scouring has hindered paleoclimate reconstructions along Greenland’s margins. Here, we report a Greenland lake sediment record that preserves both the present and previous interglacial periods. This record, combined with prior studies, demonstrates exceptionally strong warming over the northern Greenland Ice Sheet. Pronounced summer warming in this region helps explain ice sheet changes in the Early Holocene, while highlighting seemingly incongruous evidence for ice sheet extent and temperatures during the Last Interglacial. These findings may portend large future warming in this high-latitude region. Projections of future rates of mass loss from the Greenland Ice Sheet are highly uncertain because its sensitivity to warming is unclear. Geologic reconstructions of Quaternary interglacials can illustrate how the ice sheet responded during past warm periods, providing insights into ice sheet behavior and important tests for data-model comparisons. However, paleoclimate records from Greenland are limited: Early Holocene peak warmth has been quantified at only a few sites, and terrestrial sedimentary records of prior interglacials are exceptionally rare due to glacial erosion during the last glacial period. Here, we discuss findings from a lacustrine archive that records both the Holocene and the Last Interglacial (LIG) from Greenland, allowing for direct comparison between two interglacials. Sedimentary chironomid assemblages indicate peak July temperatures 4.0 to 7.0 °C warmer than modern during the Early Holocene maximum in summer insolation. Chaoborus and chironomids in LIG sediments indicate July temperatures at least 5.5 to 8.5 °C warmer than modern. These estimates indicate pronounced warming in northwest Greenland during both interglacials. This helps explain dramatic ice sheet thinning at Camp Century in northwest Greenland during the Early Holocene and, for the LIG, aligns with controversial estimates of Eemian warming from ice core data retrieved in northern Greenland. Converging geologic evidence for strong LIG warming is challenging to reconcile with inferred Greenland Ice Sheet extent during the LIG, and the two appear incompatible in many models of ice sheet evolution. An increase in LIG snowfall could help resolve this problem, pointing to the need for hydroclimate reconstructions from the region.McKay, D.I.A., Lenton, T.M., 2018. Reduced carbon cycle resilience across the Palaeocene-Eocene Thermal Maximum. Climate of the Past Discussions 2018, 1-19. past episodes of rapid carbon cycle and climate change are hypothesised to be the result of the Earth system reaching a tipping point beyond which an abrupt transition to a new state occurs. At the Palaeocene-Eocene Thermal Maximum (PETM) ~?56?Ma, and at subsequent hyperthermal events, hypothesised tipping points involve the abrupt transfer of carbon from surface reservoirs to the atmosphere. Theory suggests that tipping points in complex dynamical systems should be preceded by critical slowing down of their dynamics, including increasing temporal autocorrelation and variability. However, reliably detecting these indicators in palaeorecords is challenging, with issues of data quality, false positives, and parameter selection potentially affecting reliability. Here we show that in a sufficiently long, high-resolution palaeorecord there is consistent evidence of destabilisation of the carbon cycle in the ~?1.5?My prior to the PETM, elevated carbon cycle and climate instability following both the PETM and Eocene Thermal Maximum 2 (ETM2), and differing carbon cycle dynamics preceding the PETM and ETM2. Our results indicate a loss of resilience (weakened stabilising negative feedbacks and greater sensitivity to small shocks) in the carbon cycle before the PETM, and in the carbon-climate system following it. This pre-PETM carbon cycle destabilisation may reflect gradual forcing by the contemporaneous North Atlantic Volcanic Province eruptions. Our results are consistent with but cannot prove the existence of a tipping point for abrupt carbon release, e.g. from methane hydrate or terrestrial organic carbon reservoirs, whereas we find no support for a tipping point in deep ocean temperature.McMahon, S., Bosak, T., Grotzinger, J.P., Milliken, R.E., Summons, R.E., Daye, M., Newman, S.A., Fraeman, A., Williford, K.H., Briggs, D.E.G., 2018. A field guide to finding fossils on Mars. Journal of Geophysical Research: Planets 123, 1012-1040.: The Martian surface is cold, dry, exposed to biologically harmful radiation and apparently barren today. Nevertheless, there is clear geological evidence for warmer, wetter intervals in the past that could have supported life at or near the surface. This evidence has motivated National Aeronautics and Space Administration and European Space Agency to prioritize the search for any remains or traces of organisms from early Mars in forthcoming missions. Informed by (1) stratigraphic, mineralogical and geochemical data collected by previous and current missions, (2) Earth's fossil record, and (3) experimental studies of organic decay and preservation, we here consider whether, how, and where fossils and isotopic biosignatures could have been preserved in the depositional environments and mineralizing media thought to have been present in habitable settings on early Mars. We conclude that Noachian‐Hesperian Fe‐bearing clay‐rich fluvio‐lacustrine siliciclastic deposits, especially where enriched in silica, currently represent the most promising and best understood astropaleontological targets. Siliceous sinters would also be an excellent target, but their presence on Mars awaits confirmation. More work is needed to improve our understanding of fossil preservation in the context of other environments specific to Mars, particularly within evaporative salts and pore/fracture‐filling subsurface minerals. Plain Language Summary: This paper reviews the rocks and minerals on Mars that could potentially host fossils or other signs of ancient life preserved since Mars was warmer and wetter billions of years ago. We apply recent results from the study of Earth's fossil record and fossilization processes, and from the geological exploration of Mars by rovers and orbiters, in order to select the most favoured targets for astrobiological missions to Mars. We conclude that mudstones rich in silica and iron‐bearing clays currently offer the best hope of finding fossils on Mars and should be prioritized, but that several other options warrant further research. We also recommend further experimental work on how fossilization processes operate under conditions analogous to early Mars. McNamara, M.E., Zhang, F., Kearns, S.L., Orr, P.J., Toulouse, A., Foley, T., Hone, D.W.E., Rogers, C.S., Benton, M.J., Johnson, D., Xu, X., Zhou, Z., 2018. Fossilized skin reveals coevolution with feathers and metabolism in feathered dinosaurs and early birds. Nature Communications 9, Article 2072. are remarkable evolutionary innovations that are associated with complex adaptations of the skin in modern birds. Fossilised feathers in non-avian dinosaurs and basal birds provide insights into feather evolution, but how associated integumentary adaptations evolved is unclear. Here we report the discovery of fossil skin, preserved with remarkable nanoscale fidelity, in three non-avian maniraptoran dinosaurs and?a basal bird from the Cretaceous Jehol biota (China). The skin comprises patches of desquamating epidermal corneocytes that preserve a?cytoskeletal array of helically coiled α-keratin tonofibrils. This structure confirms that basal birds and non-avian dinosaurs shed small epidermal flakes as in modern mammals and birds, but structural differences imply that these Cretaceous taxa had lower body heat production than modern birds. Feathered epidermis acquired many, but not all, anatomically modern attributes close to the base of the Maniraptora by the Middle Jurassic.McNichol, J., Stryhanyuk, H., Sylva, S.P., Thomas, F., Musat, N., Seewald, J.S., Sievert, S.M., 2018. Primary productivity below the seafloor at deep-sea hot springs. Proceedings of the National Academy of Sciences 115, 6756-6761.. The existence of a chemosynthetic subseafloor biosphere was immediately recognized when deep-sea hot springs were discovered in 1977. However, quantifying how much new carbon is fixed in this environment has remained elusive. In this study, we incubated natural subseafloor communities under in situ pressure/temperature and measured their chemosynthetic growth efficiency and metabolic rates. Combining these data with fluid flux and in situ chemical measurements, we derived empirical constraints on chemosynthetic activity in the natural environment. Our study shows subseafloor microorganisms are highly productive (up to 1.4 Tg C produced yearly), fast-growing (turning over every 17–41 hours), and physiologically diverse. These estimates place deep-sea hot springs in a quantitative framework and allow us to assess their importance for global biogeochemical cycles.Abstract. Below the seafloor at deep-sea hot springs, mixing of geothermal fluids with seawater supports a potentially vast microbial ecosystem. Although the identity of subseafloor microorganisms is largely known, their effect on deep-ocean biogeochemical cycles cannot be predicted without quantitative measurements of their metabolic rates and growth efficiency. Here, we report on incubations of subseafloor fluids under in situ conditions that quantitatively constrain subseafloor primary productivity, biomass standing stock, and turnover time. Single-cell-based activity measurements and 16S rRNA-gene analysis showed that Campylobacteria dominated carbon fixation and that oxygen concentration and temperature drove niche partitioning of closely related phylotypes. Our data reveal a very active subseafloor biosphere that fixes carbon at a rate of up to 321 μg C?L?1?d?1, turns over rapidly within tens of hours, rivals the productivity of chemosynthetic symbioses above the seafloor, and significantly influences deep-ocean biogeochemical cycling.McVeigh, D., Skarke, A., Dekas, A.E., Borrelli, C., Hong, W.L., Marlow, J., Pasulka, A., Jungbluth, S.P., Barco, R.A., Djurhuus, A., 2018. Characterization of benthic biogeochemistry and ecology at three methane seep sites on the northern U.S. Atlantic margin. Deep Sea Research Part II: Topical Studies in Oceanography 150, 41-56. hundred methane seeps were recently discovered along the U.S. Atlantic margin, a passive margin without a major hydrocarbon basin. These seeps represent a compelling opportunity to compare and contrast geochemical parameters, as well as the distribution and composition of associated chemosynthetic ecosystems, across geologically distinct seeps. Specifically, this study characterized the physical, chemical, geological, and biological features at Veatch Canyon, New England, and Shallop Canyon methane seep sites using a suite of state-of-the-art sampling and communication tools: AUV Sentry, HOV Alvin, a video-equipped multicore, and a real-time telepresence connection to the Inner Space Center (ISC) at the University of Rhode Island. Water column backscatter data collected by AUV Sentry confirmed previously detected gas emission and further indicated the presence of 13 actively emitting gas seeps within the Veatch Canyon survey area, 5 within the New England survey area, and 15 within the Shallop Canyon survey area. Complementary high-resolution seafloor bathymetry and backscatter mapping data indicated highly rugose morphology at all surveyed seep sites including the presence of extensive rock outcrops and bivalve beds. Video collected by HOV Alvin provided visual confirmation of gas plumes and the presence of chemosynthetic communities, including microbial mats and mussel beds, as well as large outcrops of authigenic carbonate rock surrounding locations of discrete gas emission. Bathymodiolus was the dominant species observed at the Veatch Canyon methane seep site, while the deep-sea red crab, Chaceon quinquedens, dominated the New England and Shallop Canyon seep sites. Elevated pore water sulfide concentrations suggested stimulation of sulfate-coupled anaerobic oxidation of methane (AOM) and/or degradation of organic matter in seep sediments relative to non-seep sediments; AOM was observed directly within overlying authigenic carbonate rocks. DNA sequencing of the surface sediments revealed diverse sulfide-oxidizing bacteria similar to the taxa described previously at other methane seeps, including members of the Thiotrichales and Campylobacterales. Together, these analyses provide one of the first interdisciplinary descriptions of sites within this massive seep system, setting the stage for more targeted, hypothesis-driven investigations. In this context, telepresence facilitated interdisciplinary research between specialists at the ISC and scientists and engineers at sea, enabling researchers to transfer data and maximize research efforts with sampling tools at sea. Our findings suggest that although the geological setting is distinct, the surficial microbial and macrofaunal communities closely resemble those of previously described methane seeps.Meadows, V.S., Reinhard, C.T., Arney, G.N., Parenteau, M.N., Schwieterman, E.W., Domagal-Goldman, S.D., Lincowski, A.P., Stapelfeldt, K.R., Rauer, H., DasSarma, S., Hegde, S., Narita, N., Deitrick, R., Lustig-Yaeger, J., Lyons, T.W., Siegler, N., Grenfell, J.L., 2018. Exoplanet biosignatures: Understanding oxygen as a biosignature in the context of its environment. Astrobiology 18, 630-662. describe how environmental context can help determine whether oxygen (O2) detected in extrasolar planetary observations is more likely to have a biological source. Here we provide an in-depth, interdisciplinary example of O2 biosignature identification and observation, which serves as the prototype for the development of a general framework for biosignature assessment. Photosynthetically generated O2 is a potentially strong biosignature, and at high abundance, it was originally thought to be an unambiguous indicator for life. However, as a biosignature, O2 faces two major challenges: (1) it was only present at high abundance for a relatively short period of Earth's history and (2) we now know of several potential planetary mechanisms that can generate abundant O2 without life being present. Consequently, our ability to interpret both the presence and absence of O2 in an exoplanetary spectrum relies on understanding the environmental context. Here we examine the coevolution of life with the early Earth's environment to identify how the interplay of sources and sinks may have suppressed O2 release into the atmosphere for several billion years, producing a false negative for biologically generated O2. These studies suggest that planetary characteristics that may enhance false negatives should be considered when selecting targets for biosignature searches. We review the most recent knowledge of false positives for O2, planetary processes that may generate abundant atmospheric O2 without a biosphere. We provide examples of how future photometric, spectroscopic, and time-dependent observations of O2 and other aspects of the planetary environment can be used to rule out false positives and thereby increase our confidence that any observed O2 is indeed a biosignature. These insights will guide and inform the development of future exoplanet characterization missions.Medina-Sandoval, C.F., Valencia-Dávila, J.A., Combariza, M.Y., Blanco-Tirado, C., 2018. Separation of asphaltene-stabilized water in oil emulsions and immiscible oil/water mixtures using a hydrophobic cellulosic membrane. Fuel 231, 297-306. present a two-step method to prepare a hydrophobic cellulosic membrane involving a SiO2 sol-gel process, to increase surface roughness, followed by grafting of hexadecyltrimethoxysilane groups to chemically enhance the membrane’s water repellency. The modification processes induced morphological and chemical changes as observed by scanning electron microscopy and infrared spectroscopy, respectively. The hydrophobic membrane was used to separate immiscible oil/water mixtures with efficiencies over 99%. In addition, we tested the material for breaking an asphaltene–stabilized water in oil emulsion and registered separation efficiencies from 75% to 95%. The demulsification process depends on membrane surface hydrophobicity, emulsion viscosity and dispersed droplet size. The hydrophobic/oleophilic cellulose membrane was efficiently reused over 18?times to break a water/oil (50% water) emulsion. This facile solution for breaking low viscosity w/o emulsions and immiscible water/oil mixtures could be easily scalable and used to develop efficient separation methods driven solely by gravity.Meilijson, A., Ashckenazi-Polivoda, S., Illner, P., Speijer, R.P., Almogi-Labin, A., Feinstein, S., Püttmann, W., Abramovich, S., 2018. From phytoplankton to oil shale reservoirs: A 19-million-year record of the Late Cretaceous Tethyan upwelling regime in the Levant Basin. Marine and Petroleum Geology 95, 188-205. complexity of sedimentary organic-matter formation, its source to burial, and influence on bottom-water communities are addressed in this study of the 19 million years-long Upper Cretaceous Tethyan upwelling regime in the Levant. A multi-proxy approach is amalgamated into a model through which the paleoceanographic complexity of an intense and long-lasting upwelling system is better understood. A shift in primary producer assemblages and reorganization of the bottom water bacterial consortium followed the Campanian-Maastrichtian boundary, enforcing conspicuous sedimentological and faunal changes. The siliceous and phosphatic-bearing sediments of the Campanian gave way to Maastrichtian uniform and regionally distributed organic-rich carbonates, accompanied by an increase in sedimentation rates from ～1 to >6?cm/kyr. This has facilitated both the increase in organic-matter production and its excellent preservation, and through diagenetic pathways affected its elemental composition. These paleoceanographic modifications have also affected foraminiferal assemblages, from massive blooms of triserial (buliminid) benthic foraminifera during the Campanian which have sequestered diatom chloroplasts, to diverse trochospiral forms during the Maastrichtian using nitrate instead of oxygen for their respiratory pathways. We propose that shifts in the type of primary producers promote a change in the amount and type of preserved organic matter, in bottom water communities, on the lithological composition of the rock-mass, and ultimately on the hydrocarbon generation potential of the studied source rock. The continued rise of southern Tethyan sea level and global highstands during the Upper Maastrichtian, culminating into Arabian Plate-wide maximum flooding surfaces, cause the migration of upwelling activity away from the study area, terminating the high productivity sequence in the Levant.Melnikov, S., Manakongtreecheep, K., S?ll, D., 2018. Revising the structural diversity of ribosomal proteins across the three Domains of life. Molecular Biology and Evolution 35, 1588-1598. proteins are indispensable components of a living cell, and yet their structures are remarkably diverse in different species. Here we use manually curated structural alignments to provide a comprehensive catalog of structural variations in homologous ribosomal proteins from bacteria, archaea, eukaryotes, and eukaryotic organelles. By resolving numerous ambiguities and errors of automated structural and sequence alignments, we uncover a whole new class of structural variations that reside within seemingly conserved segments of ribosomal proteins. We then illustrate that these variations reflect an apparent adaptation of ribosomal proteins to the specific environments and lifestyles of living species. Finally, we show that most of these structural variations reside within nonglobular extensions of ribosomal proteins—protein segments that are thought to promote ribosome biogenesis by stabilizing the proper folding of ribosomal RNA. We show that although the extensions are thought to be the most ancient peptides on our planet, they are in fact the most rapidly evolving and most structurally and functionally diverse segments of ribosomal proteins. Overall, our work illustrates that, despite being long considered as slowly evolving and highly conserved, ribosomal proteins are more complex and more specialized than is generally recognized.Merey, ?., Longinos, S.N., 2018. Does the Mediterranean Sea have potential for producing gas hydrates? Journal of Natural Gas Science and Engineering 55, 113-134. hydrate reservoirs are considered as future global energy resource, however, minimal studies have been conducted on one of the most important historical seas to investigate the potential - the Mediterranean Sea. In this study, it is aimed to investigate this potential. According to the analyses in this study, there are many indicators of gas hydrates in the Mediterranean Sea. These indicators are mainly appropriate pressure-temperature conditions of gas hydrate formation, source gas potential, and coarse sands potential. In this study, by using the literature marine survey data and drilling data of the Mediterranean Sea such as pressure, temperature, salinity, porosity, geothermal gradient, sand content of sediments, etc., it was estimated that up to 98.2 (median) standard trillion cubic meters of methane may be available in the potential producible gas hydrates of the Mediterranean Sea. Due to the paucity of bottom simulating reflectance in the Mediterranean Sea, three hypothetical Class 3 gas hydrate reservoirs in the Mediterranean Sea conditions were simulated by using depressurization production method with/without wellbore heating with HydrateResSim numerical simulator. When the depressurization pressure is lower, much more gas is produced but until certain value. The main reason of gas production stop in these three reservoirs is hydrate reformation along the wellbore. Wellbore heating at 50?°C extended gas production for a while but could not avoid hydrate reformation along the wellbore. Ice formation due to the endothermic gas hydrate dissociation is not the cause of gas production stop because the temperature of the Mediterranean Sea sediments is high.Meshalkin, Y., Koroteev, D., Popov, E., Chekhonin, E., Popov, Y., 2018. Robotized petrophysics: Machine learning and thermal profiling for automated mapping of lithotypes in unconventionals. Journal of Petroleum Science and Engineering 167, 944-948. present a method for predicting rock types. The method is based on continuous high-resolution thermal logging along full-size core samples and being applied for rocks from a major unconventional formation. The method utilizes spatial spectral decomposition and machine learning approaches allowing automatic classification of the core samples over lithological groups within an isolated stratigraphic depth interval of a wellbore. The core samples are basically classified to the particular lithotypes by means of spectral representation of profiles of thermal properties obtained by a modern contactless method.Meyers, S.R., Malinverno, A., 2018. Proterozoic Milankovitch cycles and the history of the solar system. Proceedings of the National Academy of Sciences 115, 6363-6368.: Periodic variations in Earth’s orbit and rotation axis occur over tens of thousands of years, producing rhythmic climate changes known as Milankovitch cycles. The geologic record of these climate cycles is a powerful tool for reconstructing geologic time, for understanding ancient climate change, and for evaluating the history of our solar system, but their reliability dramatically decreases beyond 50 Ma. Here, we extend the analysis of Milankovitch cycles into the deepest stretches of Earth history, billions of years ago, while simultaneously reconstructing the history of solar system characteristics, including the distance between the Earth and Moon. Our results improve the temporal resolution of ancient Earth processes and enhance our knowledge of the solar system in deep time.Abstract: The geologic record of Milankovitch climate cycles provides a rich conceptual and temporal framework for evaluating Earth system evolution, bestowing a sharp lens through which to view our planet’s history. However, the utility of these cycles for constraining the early Earth system is hindered by seemingly insurmountable uncertainties in our knowledge of solar system behavior (including Earth–Moon history), and poor temporal control for validation of cycle periods (e.g., from radioisotopic dates). Here we address these problems using a Bayesian inversion approach to quantitatively link astronomical theory with geologic observation, allowing a reconstruction of Proterozoic astronomical cycles, fundamental frequencies of the solar system, the precession constant, and the underlying geologic timescale, directly from stratigraphic data. Application of the approach to 1.4-billion-year-old rhythmites indicates a precession constant of 85.79 ± 2.72 arcsec/year (2σ), an Earth–Moon distance of 340,900 ± 2,600 km (2σ), and length of day of 18.68 ± 0.25 hours (2σ), with dominant climatic precession cycles of ～14 ky and eccentricity cycles of ～131 ky. The results confirm reduced tidal dissipation in the Proterozoic. A complementary analysis of Eocene rhythmites (～55 Ma) illustrates how the approach offers a means to map out ancient solar system behavior and Earth–Moon history using the geologic archive. The method also provides robust quantitative uncertainties on the eccentricity and climatic precession periods, and derived astronomical timescales. As a consequence, the temporal resolution of ancient Earth system processes is enhanced, and our knowledge of early solar system dynamics is greatly improved.Miao, Y., Li, X., Lee, J., Zhou, Y., Liu, S., Chang, Y., Wang, S., 2018. Characterization of hydrocarbon/pores generation and methane adsorption in shale organic matter. Petroleum Science and Technology 36, 1187-1193. exploration and development of shale gas reservoirs has been of growing interest in the industry in recent years. It has been widely acknowledged that, during different thermal evolution stages, some characteristics including: the hydrocarbon-generation mechanism, development of organic matter pores, and methane storage/transport mechanism in organic matter/pores will affect shale gas desorption and production fundamentally. However, current research has failed to reveal them completely, which introduces large discrepancies between actual and predicted production in some shale gas reservoirs. In this paper, for the four thermal evolution stages of shale organic matter, i.e., the biochemical, thermo-catalytic, thermo-cracking and deep high temperature phases, respectively, characteristics of products generated from shale kerogen, including the form and quality of the solid frame, gas-oil ratios, and pore characteristics in organic matter (e.g., types of pores, pore wall materials) were first investigated. A new classification method for organic-matter pores was proposed. Additionally, methane absorption characteristics in shale organic matter and pores were demonstrated, the fact that water is involved during each thermal evolution phase was addressed, and current theories of solid-gas interface adsorption/desorption in the organic matter in shale were questioned. This work concluded that the system of solid-gas interface differs from actual shale reservoirs, so predicting production based on this understanding leads to significant inaccuracies. This work explained the possibility of solid-liquid interface effects in the organic matter of shale through analyzing product-generation and pore-formation mechanisms during the evolution of shale, which will directly affect potential reserves of shale. Therefore, this work should provide a basis for improving the accuracy of production predictions in actual reservoirs and should assist analysts in determining reasonable shale gas targets.Michel, A.P.M., Wankel, S.D., Kapit, J., Sandwith, Z., Girguis, P.R., 2018. In situ carbon isotopic exploration of an active submarine volcano. Deep Sea Research Part II: Topical Studies in Oceanography 150, 57-66. geologic and biogeochemical cycling of carbon in deep ocean environments has important implications for our understanding of the functioning of Earth systems across a wide range of spatial and temporal scales. To improve our ability to study the cycling and fluxes of carbon in the deep ocean, new technologies are emerging for making in situ measurements of carbon compounds over a range of environmental contexts. Within many of these deep-sea environments, fluxes of carbon compounds often occur as either venting fluids or rising gas bubbles. Key compounds of interest include methane (CH4), dissolved inorganic carbon (DIC), and carbon dioxide (CO2) – a component of DIC. In particular, measurement of the carbon isotopic composition (δ13C) of these pools can offer a better understanding of the nature of sources, fluxes, and cycling processes involving these compounds. Here we present the advancement of an in situ laser spectrometer (initially developed for measurement of δ13CCH4 only) into a sensor that can measure δ13C of both CH4 and CO2 in both deep-sea bubble plumes as well as geologic fluids. We present results of a 2014 investigation of a back arc submarine volcano (Kick’em Jenny) in the Caribbean Sea. In situ isotopic analysis of both bubbles and fluids suggest a primarily thermogenic origin for CH4 and a magmatic origin for CO2, yet highlight the occurrence of some heterogeneities indicating locally elevated contribution of organic matter to DIC fluxes.Miller, H.M., Chaudhry, N., Conrad, M.E., Bill, M., Kopf, S.H., Templeton, A.S., 2018. Large carbon isotope variability during methanogenesis under alkaline conditions. Geochimica et Cosmochimica Acta 237, 18-31. carbon isotope values (δ13CCH4?&gt;??40‰) have widely been used as evidence that methane in alkaline rock-hosted fluids was formed abiotically, particularly in serpentinizing systems. However, isotope fractionation during microbial methanogenesis is relatively understudied at high pH. We isolated a hydrogenotrophic Methanobacterium sp. from hyperalkaline subsurface fluids in the Samail ophiolite to assess how carbon and hydrogen isotope values of CH4 varied depending upon pH and carbonate mineral source (NaHCO3 or CaCO3). The hydrogen isotope fractionation αH20/CH4 (1.46–1.66) did not vary across pH. In contrast, the expressed carbon isotope fractionation, αCO2/CH4, ranged from 1.028 to 1.089. Carbon isotope fractionation increased with pH, reaching a maximum 13C depletion of ?85‰. However, the 13C depletion significantly diminished at pH?≥?9 for CaCO3-amended experiments, generating δ13CCH4 as high as ?28‰. To evaluate the large variability in δ13CCH4, we developed a steady-state model to assess how the rates of carbonate dissolution, cellular uptake of CO2 and irreversible CH4 production can affect the net isotope fractionation during methanogenesis. Methanobacterium sp. can produce highly depleted δ13CCH4 in simulated alkaline serpentinizing fluids when dissolved inorganic carbon levels are high and methanogenesis rates are slow. However, small carbon isotope fractionation occurs when rates of carbonate dissolution are slower than cellular uptake, leading to relatively high δ13CCH4 values (>～?35‰) that are traditionally interpreted to be purely “abiotic”. Thus, microbial CH4 can be produced in carbon-limited mafic and ultramafic rock-hosted environments on Earth and potentially other planetary bodies, but it may be difficult to isotopically identify biogenic methane when mineral carbonates are the dominant carbon source.Miller, R.B., Lawson, K., Sadek, A., Monty, C.N., Senko, J.M., 2018. Uniform and pitting corrosion of carbon steel by Shewanella oneidensis MR-1 under nitrate-reducing conditions. Applied and Environmental Microbiology 84, Article e00790-00718.: Despite observations of steel corrosion in nitrate-reducing environments, processes of nitrate-dependent microbially influenced corrosion (MIC) remain poorly understood and difficult to identify. We evaluated carbon steel corrosion by Shewanella oneidensis MR-1 under nitrate-reducing conditions using a split-chamber/zero-resistance ammetry (ZRA) technique. This approach entails the deployment of two metal (carbon steel 1018 in this case) electrodes into separate chambers of an electrochemical split-chamber unit, where the microbiology or chemistry of the chambers can be manipulated. This approach mimics the conditions of heterogeneous metal coverage that can lead to uniform and pitting corrosion. The current between working electrode 1 (WE1) and WE2 can be used to determine rates, mechanisms, and, we now show, extents of corrosion. When S. oneidensis was incubated in the WE1 chamber with lactate under nitrate-reducing conditions, nitrite transiently accumulated, and electron transfer from WE2 to WE1 occurred as long as nitrite was present. Nitrite in the WE1 chamber (without S. oneidensis) induced electron transfer in the same direction, indicating that nitrite cathodically protected WE1 and accelerated the corrosion of WE2. When S. oneidensis was incubated in the WE1 chamber without an electron donor, nitrate reduction proceeded, and electron transfer from WE2 to WE1 also occurred, indicating that the microorganism could use the carbon steel electrode as an electron donor for nitrate reduction. Our results indicate that under nitrate-reducing conditions, uniform and pitting carbon steel corrosion can occur due to nitrite accumulation and the use of steel-Fe(0) as an electron donor, but conditions of sustained nitrite accumulation can lead to more-aggressive corrosive conditions. Importance: Microbially influenced corrosion (MIC) causes damage to metals and metal alloys that is estimated to cost over $100 million/year in the United States for prevention, mitigation, and repair. While MIC occurs in a variety of settings and by a variety of organisms, the mechanisms by which microorganisms cause this damage remain unclear. Steel pipe and equipment may be exposed to nitrate, especially in oil and gas production, where this compound is used for corrosion and “souring” control. In this paper, we show uniform and pitting MIC under nitrate-reducing conditions and that a major mechanism by which it occurs is via the heterogeneous cathodic protection of metal surfaces by nitrite as well as by the microbial oxidation of steel-Fe(0). Minkkinen, K., Ojanen, P., Penttil?, T., Aurela, M., Laurila, T., Tuovinen, J.-P., Lohila, A., 2018. Persistent carbon sink at a boreal drained bog forest. Biogeosciences 15, 3603-3624. of peatlands is expected to turn these ecosystems into carbon sources to the atmosphere. We measured carbon dynamics of a drained forested peatland in southern Finland over 4 years, including one with severe drought during growing season. Net ecosystem exchange (NEE) of carbon dioxide (CO2) was measured with the eddy covariance method from a mast above the forest. Soil and forest floor CO2 and methane (CH4) fluxes were measured from the strips and from ditches with closed chambers. Biomass and litter production were sampled, and soil subsidence was measured by repeated levellings of the soil surface. The drained peatland ecosystem was a strong sink of carbon dioxide in all studied years. Soil CO2 balance was estimated by subtracting the carbon sink of the growing tree stand from NEE, and it showed that the soil itself was a carbon sink as well. A drought period in one summer significantly decreased the sink through decreased gross primary production. Drought also decreased ecosystem respiration. The site was a small sink for CH4, even when emissions from ditches were taken into account. Despite the continuous carbon sink, peat surface subsided slightly during the 10-year measurement period, which was probably mainly due to compaction of peat. It is concluded that even 50 years after drainage this peatland site acted as a soil C sink due to relatively small changes in the water table and in plant community structure compared to similar undrained sites, and the significantly increased tree stand growth and litter production. Although the site is currently a soil C sink, simulation studies with process models are needed to test whether such sites could remain C sinks when managed for forestry over several tree-stand rotations.Mirnaghi, F.S., Soucy, N., Hollebone, B.P., Brown, C.E., 2018. Rapid fingerprinting of spilled petroleum products using fluorescence spectroscopy coupled with parallel factor and principal component analysis. Chemosphere 208, 185-195. characterization of spilled petroleum products in an oil spill is necessary for identifying the spill source, selection of clean-up strategies, and evaluating potential environmental and ecological impacts. Existing standard methods for the chemical characterization of spilled oils are time-consuming due to the lengthy sample preparation for analysis. The main objective of this study is the development of a rapid screening method for the fingerprinting of spilled petroleum products using excitation/emission matrix (EEM) fluorescence spectroscopy, thereby delivering a preliminary evaluation of the petroleum products within hours after a spill. In addition, the developed model can be used for monitoring the changes of aromatic compositions of known spilled oils over time. This study involves establishing a fingerprinting model based on the composition of polycyclic and heterocyclic aromatic hydrocarbons (PAH and HAHs, respectively) of 130 petroleum products at different states of evaporative weathering. The screening model was developed using parallel factor analysis (PARAFAC) of a large EEM dataset. The significant fluorescing components for each sample class were determined. After which, through principal component analysis (PCA), the variation of scores of their modeled factors was discriminated based on the different classes of petroleum products. This model was then validated using gas chromatography-mass spectrometry (GC-MS) analysis. The rapid fingerprinting and the identification of unknown and new spilled oils occurs through matching the spilled product with the products of the developed model. Finally, it was shown that HAH compounds in asphaltene and resins contribute to ≥4-ring PAHs compounds in petroleum products.Mirshahani, M., Bahrami, H., Rashidi, M., Tarhandeh, E., Khani, B., 2018. Organic geochemical evaluation of potential Cenozoic source rocks in the Moghan Basin, NW Iran: Implications for hydrocarbon exploration. Journal of Petroleum Geology 41, 393-410. detailed organic geochemical evaluation of potential source rock samples (n = 350) collected from outcrops and wells in the Cenozoic Moghan Basin, NW Iran, was undertaken using whole rock (Rock‐Eval pyrolysis, organic petrography) and extract (GC and GC‐MS) analyses. The studied intervals consist of Eocene to Miocene shale/sandstone successions interpreted to have been deposited in nearshore marine conditions. Three potential source rock intervals were investigated: the Salm Aghaji Formation (lower Middle Eocene), the lower member of the Ojagheshlagh Formation (upper Middle Eocene), and the Ziveh Formation (Oligo‐Miocene). The results were used to evaluate the samples' petroleum potential and thermal maturity. A range of maturity parameters indicate that these source rocks are in the early oil generation window in the study area, and outcrop samples are less mature than subsurface samples. Rock‐Eval Tmax values for the outcrop and subsurface samples range from 410–442 °C and 438–445 °C, respectively. At a regional scale, there is an eastwards increase in thermal maturity which reaches the main oil window (ca. 3000 m) in the east of the Moghan Basin, as indicated by both VRo measurements and maturity‐sensitive biomarkers. Fair to moderate TOC contents (averaging 0.72, 0.99 and 0.78 wt.%) were recorded respectively for the Salm Aghaji, Ojagheshlagh and Ziveh Formations. Average HI values of less than 200 mg HC/g TOC (131, 178 and 104 respectively for the three formations) indicate the dominance of Type III kerogen. This is consistent with detailed molecular parameters which show a dominance of C29 steranes over C27 and C28 homologues. These observations are interpreted to indicate a nearshore marine depositional environment with an abundant terrigenous organic matter input. However, HI values of several samples fall into the range of 250 to 650 mg HC/g TOC showing the local presence of Type II kerogen. Thus the geochemistry and maturity results from this study suggest that shale‐rich intervals in the Salm Aghaji, Ojagheshlagh and Ziveh Formations may be potential source rocks for the oil shows which have been recorded in wells in the Moghan Basin. Mishra, S., Singh, V.P., 2018. Palynology, palynofacies, and taphonomical studies of Kamthi Formation, (Godavari Graben), southern India: Implications to biostratigraphy, palaeoecology, and depositional environment. International Journal of Coal Geology 195, 102-124. ambiguity regarding the age and palaeoecology of the Kamthi Formation is persisting for several years. In order to find the scientific answers to this problem, an integrated approach has been adopted on the samples collected from a 604?m thick sedimentary sequence (borehole) of the Kamthi Formation (late Permian), Godavari Graben. The compilation of detailed investigation includes the palynology, palynofacies and taphonomic studies, in order to establish the age, reconstructing the palaeoecology and inferring the environment of deposition. The palynological investigation indicates the presence of two informal palynoassemblages: the lower Palynoassemblage-A (Faunipollenites?+?Striasulcites), corresponds to the coarse-grained sandstone dominated basal part, and the Palynoassemblage-B (Densipollenites?+?striate bisaccates) occur in the upper fine-grained sandstone and shale dominated sequence. A detailed Gondwanan correlation of the palynoassemblages assign a late Permian age to the palynoflora: Palynoassemblage-A belongs to the Guadalupian age while Palynoassemblage-B corresponds to the Lopingian age.The dominance of glossopterids, peltasperms, conifers and Cordaites derived pollens indicate the presence of thick arborescent palaeovegetation. The rich cryptogam spore assemblage (algal, fillicopsid, and equisetopsid) constitute the opportunistic and rare component of the understorey flora. The present study suggests that the lycopsids along with few acritarchs make their appearance post-Guadalupian.The taphonomic studies infer that the palynoassemblages are greatly influenced by the structure of spores and pollen saccus. Further, the palynofacies analysis reveals a cyclic change in the environment fluctuating from unstable oxic to the stable anoxic environment. The occurrence of microscopic charcoal from the late Permian also suggests palaeo-wildfire events in the hinterland.Mitnick, E.H., Lammers, L.N., Zhang, S., Zaretskiy, Y., DePaolo, D.J., 2018. Authigenic carbonate formation rates in marine sediments and implications for the marine δ13C record. Earth and Planetary Science Letters 495, 135-145. isotope (δ13C) variations measured in carbonates have been attributed to large-scale phenomena throughout Earth history, such as changes in atmospheric oxygen or global glaciations. These interpretations follow from a model wherein the δ13C of marine dissolved inorganic carbon (DIC) is controlled by the relative sedimentary burial rates of biogenic carbonate (BC) and organic carbon (OC). A new model proposes authigenic carbonate (AC) as a third major sedimentary C pool, implying that δ13C anomalies are not necessarily indicative of extreme changes in the global carbon cycle and/or atmospheric oxygen. Two conditions are required for AC formation to significantly alter bulk carbonate δ13C: the AC isotopic composition must be at least ～3‰ different from that of BC and the AC/BC ratio must be >0.1. We use pore fluid Ca and Sr concentrations to estimate rates of AC formation in Late Cenozoic marine sediments, then calculate relative fractions of AC, OC, and BC. Today AC is not expected to constitute a significant fraction of total sedimentary carbon (AC+OC+BC) globally; however, there are modern sites where local conditions promote elevated AC/BC and anaerobic metabolisms can alter the δ13C of pore fluids. We investigate these sites to determine what conditions might enable AC to alter δ13C of marine DIC. We find there is very little net addition of AC relative to BC, but large quantities of AC form today across many settings via recrystallization. In settings where remineralization of organic matter causes recrystallized carbonate to form with modified δ13C, AC/BC is generally too low for this recrystallization to significantly shift the δ13C of the bulk carbonate. However, exceptions are found in sites with very low BC and extensive methane oxidation, suggesting that this environment type would need to be globally extensive in the past in order for AC formation to change the δ13C of marine DIC.Moelling, K., 2018. Commentary to: Cause of Cambrian explosion - Terrestrial or cosmic? Steele, E.J. et?al. Progress in Biophysics and Molecular Biology 136, 24. authors reflect about the emergence of life on our planet, the cause for the Cambrian explosion about 500 Mio years ago, the origin of octopus and intelligence and how all of this culminated in the emergence of mankind.They present a fantastic overview of the various hypotheses about the evolution of life on our planet and the contribution of extraterrestrial elements. The review includes many references, several different opinions and ranges all the way to the up-to-date literature.This is very useful and inspiring and opens a narrow view onto our earth into space. Thinking of the influence of the universe on our planet may be new to many readers, especially since only during recent years our understanding of the universe has changed. We learnt a lot new facts through astrophysics, astrobiology, and astrochemistry. One of them is the new result that there are billions of habitable planets in our galaxy. Rocks from space coming to us by asteroids or meteorites, hitting our planet, transported many components, which originated from extraterrestrial space, such as organic building blocks and minerals which allowed to generate outside of the earth nucleotides, aminoacis, lipids - the three main components of terrestrial life. Their existence outside of our planet is clearly evidence-based. Not only monomers but possibly also polymers formed.Then later during evolution, even till today the genetic material has increased by the contribution of viruses - they are indeed the drivers of evolution by their complexity, variability, enormous abundance, and interaction with all cells known in the genetic tree.The authors take, however, one more step. Their view differs from common scientific concepts and available evidence, claiming that the origin of viruses, microbes and even animals all the way to tardigradus - originate from space. Retroviruses caused the Cambrian explosion of all animal species. Indeed, one can find close to 50% of retroviral sequences in the human genome, which are even designated as viral fossils - but this does not tell us where the viruses came from. If if they were formed somewhere in the universe and travelled in some protective rocks or ice, there is no evidence for it at all. And how did they form in the first place?There are several explanations why the Cambrian explosion occurred - animals started to go on land, used and produced oxygen, had collagen allowing multicellular organisms - but the notion that viruses from extraterrestrial space are the main drivers - is uniquely presented here in this article. The authors believe this and use strong expressions, describing it as evidence -based, yet without any of the necessary evidence. As an excuse they point out to other previous unconventional ideas during history of science which turned out to be true later - this is the argument the authors use. They even find their idea “plausible” - but it is hard to follow their thinking in this respect. So this article is useful, calling for attention, and it is worth thinking about - yet the main statement about viruses, microbes and even animals which came to us from space, cannot be taken seriously.Montes-Bayón, M., Sharar, M., Corte-Rodriguez, M., 2018. Trends on (elemental and molecular) mass spectrometry based strategies for speciation and metallomics. TrAC Trends in Analytical Chemistry 104, 4-10. capabilities of electrospray ionization (ESI) and matrix assisted laser desorption/ionization (MALDI) to permit species identification in combination with inductively coupled plasma (ICP) mass spectrometry to conduct element-tagged species monitoring have been exploited for a number of applications in speciation studies over the years. In this review, we report the new trends in the combined application of these techniques to address the structural and quantitative insights for different speciation/metallomics issues including the monitoring of natural elemental labels and drug metabolism products as well as the characterization of metallic nanoparticles and their corresponding metal ions. In addition, the trends on the analysis of trace elements in single cells by elemental MS together with the exponential growth of the imaging experiments, are also covered.Morelle, J., Schapira, M., Fran?oise, S., Courtay, G., Orvain, F., Claquin, P., 2018. Dynamics of exopolymeric carbon pools in relation with phytoplankton succession along the salinity gradient of a temperate estuary (France). Estuarine, Coastal and Shelf Science 209, 18-29. parallel to phytoplankton community dynamics, transparent exopolymeric particles (TEP) and exopolymeric substances (EPS) were investigated along the salinity gradient of a temperate estuary (Seine estuary, Normandy, France) over the course of a year. The phytoplankton community was mainly dominated by marine diatom species (especially Skeletonema sp., Nitzschia sp., and Paralia sulcata) associated with a spring bloom of pico-eukaryotes and the development of Cryptophyceae in summer. The decreases in species richness and salinity were correlated along the estuary and a significant exponential relationship between species richness and primary production was identified. Concentrations of TEP and EPS (soluble and bound carbohydrates) are highly dynamic in this estuary and can reach respectively 69?mgC L?1, and 33?mgC L?1. TEP distribution was mainly related to physical factors (hydrodynamics, maximum turbidity zone formation and sediment resuspension) probably produced by stressed or dying phytoplankton, while EPS appeared to be excreted during the phytoplankton spring bloom. Soluble and bound EPS appear to be related to Skeletonema sp. and Cryptophyceae occurrences. This paper presents the dynamic pattern of these carbon pools, which play an important role in the trophic network and influence the flocculation processes involved in the fate of both organic and inorganic matter.Moschos, V., Kumar, N.K., Daellenbach, K.R., Baltensperger, U., Prév?t, A.S.H., El Haddad, I., 2018. Source apportionment of brown carbon absorption by coupling ultraviolet–visible spectroscopy with aerosol mass spectrometry. Environmental Science & Technology Letters 5, 302–308. impact of brown carbon (BrC) on climate has been widely acknowledged but remains uncertain, because either its contribution to absorption is being ignored in most climate models or the associated mixed emission sources and atmospheric lifetime are not accounted for. In this work, we propose positive matrix factorization as a framework to apportion the contributions of individual primary and secondary organic aerosol (OA) source components of BrC absorption, by combining long-term aerosol mass spectrometry (AMS) data with concurrent ultraviolet–visible (UV-vis) spectroscopy measurements. The former feature time-dependent factor contributions to OA mass, and the latter consist of wavelength-dependent absorption coefficients. Using this approach for a full-year case study, we estimate for the first time the mass absorption efficiency (MAE) of major light-absorbing water-soluble OA components in the atmosphere. We show that secondary biogenic OA contributes negligibly to absorption despite dominating the mass concentration in the summer. In contrast, primary and secondary wood burning emissions are highly absorbing up to 500 nm. The approach allowed us to constrain their MAE within a confined range consistent with previous laboratory work, which can be used in climate models to estimate the impact of BrC from these emissions on the overall absorption.Mudedla, S.K., Kumar, C.V.S., Suresh, A., Baskar, P., Dash, P.S., Subramanian, V., 2018. Water catalyzed pyrolysis of oxygen functional groups of coal: A density functional theory investigation. Fuel 233, 328-335. pyrolysis mechanism of carboxylic and hydroxyl groups which are present in the coal has been investigated with the help of density functional theory calculations. The role of water in the pyrolysis reaction mechanisms has also been investigated by the calculation of activation energy barriers. The activation energy barriers for the water mediated reactions are less when compared to thermal pyrolysis process. The results show the significant decrease in the energy barriers for decarboxylation reactions than the hydroxyl groups in the presence of water. Therefore, water can significantly decrease the oxygen content in the non-coking coals with high content of carboxylic groups.Mudgil, D., Baskar, S., Baskar, R., Paul, D., Shouche, Y.S., 2018. Biomineralization potential of Bacillus subtilis, Rummeliibacillus stabekisii and Staphylococcus epidermidis strains in vitro isolated from speleothems, Khasi Hill Caves, Meghalaya, India. Geomicrobiology Journal 35, 675-694. were isolated and identified from speleothems at Khasi hill caves, Meghalaya. The aim was to understand their biomineralization potential. Analyses of the speleothems from Krem Soitan, Krem Mawpun, and Krem Lawbah using scanning electron microscope (SEM) showed evidences for microbe–mineral interactions. SEM showed microbial reticulate and beaded filaments, cells, fiber calcites, and clusters of coccoid-like structures. A total of 113 bacterial strains were isolated and identified by a combination of conventional and molecular based tools. 105 strains that were sequenced belonged to the genus: Bacillus, Rummeliibacillus, Staphylococcus, and Brevibacterium. The BLASTn sequence search of 16S rRNA sequences with the National Centre for Biotechnology Information database to establish the identity of the strains yielded similarity scores of ≥99% with the respective organisms. The strains were identified as Bacillus simplex, Bacillus gaemokensis, Bacillus subtilis, Bacillus thuringiensis, Bacillus albus, Bacillus cereus, Bacillus anthracis, Bacillus weihenstephanensis, Rummeliibacillus stabekisii, Bacillus wiedmannii, Staphylococcus epidermidis, Rummeliibacillus pycnus, Kurthia zopfii, and Brevibacterium frigoritolerans. These strains were tested for biomineralization on B-4 medium. Five strains (B. subtilis, R. stabekisii, Staphylococcus epiderdimis, B. cereus, and B. wiedmannii) had the capability to precipitate biominerals in vitro. B. subtilis, R. stabekisii, and S. epidermidis precipitated 0.24, 0.36, and 0.35 g/L of biominerals at 22°C at the end of the four week experiment period. These strains increased the pH of the medium from 7 to 8.95. The precipitated biominerals were imaged using an ultra-high resolution field emission SEM. X-ray diffraction of the biomineral precipitated by R. stabekisii showed that it was composed of vaterite and jungite. Whereas S. epidermidis showed that it was composed of calcite, vaterite, and jungite. B. subtilis produced small, circular calcite crystals. This is the first comprehensive report on the possible evidences about the role of R. stabekisii and S. epidermidis in calcite precipitation isolated from speleothems in the Indian caves. These results allow us to postulate that the identified strains have biomineralization potential. Further evidences of the coexistence of exopolysaccharides, whisker fiber calcites, microbial filaments, and coccoid-like forms point to biogenic inputs in the cave mineral formations.Munson-McGee, J.H., Peng, S., Dewerff, S., Stepanauskas, R., Whitaker, R.J., Weitz, J.S., Young, M.J., 2018. A virus or more in (nearly) every cell: ubiquitous networks of virus–host interactions in extreme environments. The ISME Journal 12, 1706-1714. application of viral and cellular metagenomics to natural environments has expanded our understanding of the structure, functioning, and diversity of microbial and viral communities. The high diversity of many communities, e.g., soils, surface ocean waters, and animal-associated microbiomes, make it difficult to establish virus-host associations at the single cell (rather than population) level, assign cellular hosts, or determine the extent of viral host range from metagenomics studies alone. Here, we combine single-cell sequencing with environmental metagenomics to characterize the structure of virus–host associations in a Yellowstone National Park (YNP) hot spring microbial community. Leveraging the relatively low diversity of the YNP environment, we are able to overlay evidence at the single-cell level with contextualized viral and cellular community structure. Combining evidence from hexanucelotide analysis, single cell read mapping, network-based analytics, and CRISPR-based inference, we conservatively estimate that >60% of cells contain at least one virus type and a majority of these cells contain two or more virus types. Of the detected virus types, nearly 50% were found in more than 2 cellular clades, indicative of a broad host range. The new lens provided by the combination of metaviromics and single-cell genomics reveals a network of virus–host interactions in extreme environments, provides evidence that extensive virus–host associations are common, and further expands the unseen impact of viruses on cellular life.Myshakin, E.M., Singh, H., Sanguinito, S., Bromhal, G., Goodman, A.L., 2018. Numerical estimations of storage efficiency for the prospective CO2 storage resource of shales. International Journal of Greenhouse Gas Control 76, 24-31. shale formations might be an attractive geologic reservoir for permanent carbon dioxide (CO2) storage. Shale formations applicable for storage require previous hydrocarbon production to deplete a reservoir, hydraulic fracturing to provide a highly-permeable stimulated zone, sufficient depths (generally > 800?m or 2600 feet) to maintain CO2 in a supercritical state, and an overlying seal to prevent CO2 migration to underground sources of drinking water and into the atmosphere. CO2 is stored in shale as a free phase within fractures and matrix pores, and as a sorbed phase on organic matter and clay minerals. Recently in our previous work, we presented a screening-level assessment methodology for CO2 storage in shales using a volumetric approach. The approach deals with reduction of CO2 storage through estimations of efficiency factors based on petrophysical properties (i.e., bulk volume, porosity, sorption, etc.) and their limitations on fluid transport. Here, we conducted numerical simulations using the FRACGEN/NFFLOW simulator to study the CO2 injection into a depleted hydro-fractured shale reservoir to estimate storage efficiencies using a range of reservoir parameters and injection scenarios. Specifically, the ranges for two efficiency factors, E ? and E S , measure the effectiveness of free and sorbed CO2 storage. These efficiency factors were estimated to have P10 to P90 probability ranges of 0.15 to 0.36 for E ? and 0.11 to 0.24 for E S , reported after 60 years of CO2 injection.Najafi-Marghmaleki, A., Kord, S., Hashemi, A., Motamedi, H., 2018. Experimental investigation of efficiency of MEOR process in a carbonate oil reservoir using Alcaligenes faecalis: Impact of interfacial tension reduction and wettability alteration mechanisms. Fuel 232, 27-35. Enhanced Oil Recovery (MEOR) is a term which is attributed to the process of utilizing bacterial activity for increasing the recovery factor of oil reservoirs. This process relies on several mechanisms especially interfacial tension reduction and wettability alteration mechanisms. The main purpose of this work is to evaluate the impact of these mechanisms during MEOR process for microorganism isolated from formation water of one of the Iranian southwest carbonate oil reservoirs. The isolated microorganism was identified to be Alcaligenes faecalis. The optimum condition for growth of microorganism was found at 28?°C, pH?=?7, carbon to nitrogen ratio of 30 and 3% salinity. Results show that the selected microorganism is able to reduce the interfacial tension between formation brine and crude oil from 28.1?mN/m to 8.4?mN/m and alter the wettability of reservoir rock from approximately 156° to 86° which represents a change from oil-wet condition toward intermediate-wet. Results show that the isolated microorganism is able to produce 8.2% and 5.2% additional oil recovery in respective shut in and quick flooding scenarios. This show that the isolated microorganism is efficient in production of additional oil as a part of tertiary oil recovery process.Nakamura, H., 2018. Current status of water environment and their microbial biosensor techniques – Part I: Current data of water environment and recent studies on water quality investigations in Japan, and new possibility of microbial biosensor techniques. Analytical and Bioanalytical Chemistry 410, 3953-3965. my 2010 review, I addressed conventional water analysis and biosensing of organic pollutants in Japan between 1960s and 2000s. It is now timely to reexamine current analytical and biomonitoring approaches in view of the new challenges in assessing pollution, particularly in closed water bodies, as pollutants tend to accumulate in these endorheic basins. In the present review series, I presented current water environment and its microbial biosensors. In this part, I presented current data of the water quality of these water bodies in Japan and established the need to further develop microbial biosensor technologies to address and monitor water quality here.Nakamura, H., 2018. Current status of water environment and their microbial biosensor techniques – Part II: Recent trends in microbial biosensor development. Analytical and Bioanalytical Chemistry 410, 3967-3989. Part I of the present review series, I presented the current state of the water environment by focusing on Japanese cases and discussed the need to further develop microbial biosensor technologies for the actual water environment. I comprehensively present trends after approximately 2010 in microbial biosensor development for the water environment. In the first section, after briefly summarizing historical studies, recent studies on microbial biosensor principles are introduced. In the second section, recent application studies for the water environment are also introduced. Finally, I conclude the present review series by describing the need to further develop microbial biosensor technologies.Nakamura, R., Naruse, M., 2018. Spectroscopic analysis of colorants used for bachiru carving technique found in the Shosoin treasures. Studies in Conservation 63, 267-276. Shosoin treasures, which include the belongings of Emperor Shomu (CE 701?756) and Empress Komyo (CE 701?760), have an honorable origin and have been continuously handed down for generations since the eighth century in the Todaiji temple in Nara, Japan. Some of the beautiful artifacts found among the treasures display the bachiru carving technique, in which a delicate pattern is produced by carving dyed ivory or antler using additional painting. To elucidate the colorants used for dyeing and painting in the bachiru technique, non-invasive scientific analyses using fiber optic reflectance spectrometry in the visible region, X-ray fluorescence spectroscopy, and X-ray diffraction were performed for eight treasures: a go game board, two go pieces, a nyoi (ritual nail pole), a kugo harp, a bird-shaped accessory, a kaburaya arrow, and a ritual ruler. Second derivatization of the reflectance spectra led to characterization of the dyes in the treasures as sappanwood, lac, madder, gromwell, and indigo. Lac and atacamite were respectively identified in the red and green areas of the painting by reflectance spectrometry and X-ray diffractometry. These results indicated the use of a variety of colorants for the bachiru carving technique in the eighth century.Nan, H., Anderson, J.L., 2018. Ionic liquid stationary phases for multidimensional gas chromatography. TrAC Trends in Analytical Chemistry 105, 367-379. liquids (ILs) are a class of organic salts that meet many of the requirements of GC stationary phases including high thermal stability, high viscosity, and tunable selectivity through the modification of the chemical structure. IL-based columns, when incorporated either in the first or second dimension, can offer unique selectivity compared to polydimethyl(siloxane) and poly(ethyleneglycol) derived GC stationary phases for the separation of complex samples by multidimensional gas chromatography. In addition, IL-based columns are emerging as superior choices for applications requiring high polarity as well as high thermal stability. The present contribution provides an overview on IL-based stationary phases for multidimensional gas chromatography with an emphasis on developments in the period from 2012 to early 2018. The analysis of various analytes (e.g., fatty acids, polycyclic aromatic sulfur heterocycles, and biodiesels) in complex matrices as well as the developments of new IL-based stationary phases for multidimensional gas chromatography are described.Napp, A.P., Pereira, J.E.S., Oliveira, J.S., Silva-Portela, R.C.B., Agnez-Lima, L.F., Peralba, M.C.R., Bento, F.M., Passaglia, L.M.P., Thompson, C.E., Vainstein, M.H., 2018. Comparative metagenomics reveals different hydrocarbon degradative abilities from enriched oil-drilling waste. Chemosphere 209, 7-16. oil drilling process generates large volumes of waste with inadequate treatments. Here, oil drilling waste (ODW) microbial communities demonstrate different hydrocarbon degradative abilities when exposed to distinct nutrient enrichments as revealed by comparative metagenomics. The ODW was enriched in Luria Broth (LBE) and Potato Dextrose (PDE) media to examine the structure and functional variations of microbial consortia. Two metagenomes were sequenced on Ion Torrent platform and analyzed using MG-RAST. The STAMP software was used to analyze statistically significant differences amongst different attributes of metagenomes. The microbial diversity presented in the different enrichments was distinct and heterogeneous. The metabolic pathways and enzymes were mainly related to the aerobic hydrocarbons degradation. Moreover, our results showed efficient biodegradation after 15 days of treatment for aliphatic hydrocarbons (C8-C33) and polycyclic aromatic hydrocarbons (PAHs), with a total of about 50.5% and 46.4% for LBE and 44.6% and 37.9% for PDE, respectively. The results obtained suggest the idea that the enzymatic apparatus have the potential to degrade petroleum compounds.Naveen, P., Asif, M., Ojha, K., 2018. Integrated fractal description of nanopore structure and its effect on CH4 adsorption on Jharia coals, India. Fuel 232, 190-204. pore surface heterogeneity and pore matrix irregularities have a decisive influence on the gas adsorption capacity and transportation in the coalbed methane (CBM) reservoir. This study integrates novel idea of relating the multiple approaches to customize the obtained results from analytical techniques to attain efficient elucidation and quantification of pore features and its influence on gas storage and transport in CBM reservoirs. Fractal profiles are analyzed to evolve fractal dimensions from LPA-N2 and imaging techniques for surface fractals and matrix fractals. Measured results of fractal dimension depict surface texture, complexity and heterogeneity of pore structure, thereby its relationship with CH4 adsorption are investigated. A 3D model of pore structure and connectivity are reconstructed to quantify the porous regions using 2D FE-SEM data and 3D tomographic interface-Amira software. In contrast to the conventional surface fractal approaches, this technique helps to illustrate pore structure and provides realistic pore connectivity. Study analysis reveals that the pores with higher surface fractal dimension, i.e. (DS?>?2.65) have possibly large amount of adsorption sites, where adsorption of gases becomes easier than desorption due to surface roughness. However, the higher matrix fractal dimension results in a more complex pore microstructure in contrary to that of surface fractal dimension, which directly effects the adsorption mechanism causing pore filling adsorption and the adsorption capacity decreases because of relatively higher liquid/gas surface tension.Ndiripo, A., Pasch, H., 2018. Comprehensive analysis of oxidized waxes by solvent and thermal gradient interaction chromatography and two-dimensional liquid chromatography. Analytical Chemistry 90, 7626-7634. report addresses the comprehensive analysis of oxidized/functionalized polyethylene waxes according to chemical composition and molar mass by selective chromatographic methods. For the first time, tailored high-temperature interaction chromatography in solvent gradient (HT-SGIC) and thermal gradient (HT-TGIC) modes are used for the chemical composition separation of these materials. Separation protocols are developed using three model wax samples with different degrees of oxidation. For the chromatographic separations polar silica gel is used as the stationary phase. Solvent gradients of decane and cyclohexanone are used in HT-SGIC at 110 °C to separate the bulk waxes into several heterogeneous fractions according to polarity and the type of functionality. Column temperature and gradient manipulation are shown to influence chromatographic resolution and retention. The HT-SGIC investigations are complemented by HT-TGIC separations where a solvent mixture of decane and cyclohexanone is used as the mobile phase in isocratic mode. It is shown that HT-SGIC and HT-TGIC provide different types of separation, however, both are predominantly based on differences in functionality. To provide comprehensive information on chemical composition (functionality) and molar mass, HT-SGIC and HT-TGIC are coupled to HT-SEC, using ortho-dichlorobenzene as the second dimension mobile phase. Clear differences between oxidized and nonoxidized waxes are detected in HT-2D-LC providing comprehensive information on the molecular heterogeneity of these materials.Nesse, L.L., Simm, R., 2018. Biofilm: A hotspot for emerging bacterial genotypes. Advances in Applied Microbiology 103, 223-246. have the ability to adapt to changing environments through rapid evolution mediated by modification of existing genetic information, as well as by horizontal gene transfer (HGT). This makes bacteria a highly successful life form when it comes to survival. Unfortunately, this genetic plasticity may result in emergence and dissemination of antimicrobial resistance and virulence genes, and even the creation of multiresistant “superbugs” which may pose serious threats to public health. As bacteria commonly reside in biofilms, there has been an increased interest in studying these phenomena within biofilms in recent years. This review summarizes the present knowledge within this important area of research.Studies on bacterial evolution in biofilms have shown that mature biofilms develop into diverse communities over time. There is growing evidence that the biofilm lifestyle may be more mutagenic than planktonic growth. Furthermore, all three main mechanisms for HGT have been observed in biofilms. This has been shown to occur both within and between bacterial species, and higher transfer rates in biofilms than in planktonic cultures were detected. Of special concern are the observations that mutants with increased antibiotic resistance occur at higher frequency in biofilms than in planktonic cultures even in the absence of antibiotic exposure. Likewise, efficient dissemination of antimicrobial resistance genes, as well as virulence genes, has been observed within the biofilm environment. This new knowledge emphasizes the importance of biofilm awareness and control.Nevalainen, M., Helle, I., Vanhatalo, J., 2018. Estimating the acute impacts of Arctic marine oil spills using expert elicitation. Marine Pollution Bulletin 131, 782-792. maritime traffic in the Arctic has heightened the oil spill-related risks in this highly sensitive environment. To quantitatively assess these risks, we need knowledge about both the vulnerability and sensitivity of the key Arctic functional groups that may be affected by spilled oil. However, in the Arctic these data are typically scarce or lacking altogether. To compensate for this limited data availability, we propose the use of a probabilistic expert elicitation methodology, which we apply to seals, anatids, and seabirds. Our results suggest that the impacts of oil vary between functional groups, seasons, and oil types. Overall, the impacts are least for seals and greatest for anatids. Offspring seem to be more sensitive than adults, the impact is greatest in spring, and medium and heavy oils are the most harmful oil types. The elicitation process worked well, yet finding enough skilled and motivated experts proved to be difficult.Ni, Y., Gao, J., Chen, J., Liao, F., Liu, J., Zhang, D., 2018. Gas generation and its isotope composition during coal pyrolysis: Potential mechanism of isotope rollover. Fuel 231, 387-395. studies on both conventional (thermogenic gas) and unconventional (shale gas) gases show comparable carbon/hydrogen isotope rollover, i.e., before the rollover point, carbon/hydrogen isotope increases with increasing thermal maturity (or decreasing gas wetness), while after the rollover point, the gas component (i.e., ethane, propane, etc.) becomes more depleted in 13C or 2H with increasing thermal maturity. In order to further investigate potential mechanism of the isotope rollover, combined with previous researches on isotope rollover, this study carried out two batches of pyrolysis experiments on a low mature coal sample from the Songliao Basin, China at constant temperatures for about 72?h under the condition with added water and without added water. The results demonstrate that carbon and hydrogen isotope rollover of ethane and propane started at 500?°C, no matter with added water or without added water. Combined with previous studies on gases of various origins, it is found that such isotopic anomalies were a common phenomenon at high thermal mature stage, despite of what kind of the source rocks and whether adding water or not under the laboratory condition. This is likely caused by the mixing of gases directly from the decomposition of macromolecule of kerogen and those from the tightly entrapped straight-chain species in kerogen at relatively high thermal mature stage. These straight-chain species are normally entrapped in the kerogen, and will probably be released at high thermal maturation stage. Marine facies source rocks from southern China also demonstrate the existence of such tightly entrapped hydrocarbons at very high thermal maturity. The results may have important significance on the gas exploration at relatively high mature stage and have a guidance on the gas production changes during the exploration.Nicol, C., Ellery, A., Lynch, B., Cloutis, E., de Croon, G., 2018. Martian methane plume models for defining Mars rover methane source search strategies. International Journal of Astrobiology 17, 228-238. detection of atmospheric methane on Mars implies an active methane source. This introduces the possibility of a biotic source with the implied need to determine whether the methane is indeed biotic in nature or geologically generated. There is a clear need for robotic algorithms which are capable of manoeuvring a rover through a methane plume on Mars to locate its source. We explore aspects of Mars methane plume modelling to reveal complex dynamics characterized by advection and diffusion. A statistical analysis of the plume model has been performed and compared to analyses of terrestrial plume models. Finally, we consider a robotic search strategy to find a methane plume source. We find that gradient-based techniques are ineffective, but that more sophisticated model-based search strategies are unlikely to be available in near-term rover missions.Nkwain, F.N., Demyan, M.S., Rasche, F., Dignac, M.-F., Schulz, E., K?tterer, T., Müller, T., Cadisch, G., 2018. Coupling pyrolysis with mid-infrared spectroscopy (Py-MIRS) to fingerprint soil organic matter bulk chemistry. Journal of Analytical and Applied Pyrolysis 133, 176-184. novel method coupling pyrolysis with mid-infrared spectroscopy (Py-MIRS) was developed to characterize soil organic matter (SOM) chemistry in soils. The pyrolyzer was interfaced to the MIR spectrometer by means of a Brill cell? (CDS Analytica). The set-up generates pyrolysis fingerprint spectra from which individual pyrolysis products can be related to SOM bulk chemistry. Py-MIRS development involved the testing of experimental conditions like pyrolysis temperature (550, 700, 1000?°C), heating rate (20?°C?s?1 and 20?°C?ms?1) and time (15, 30 and 60?s) using reference standard compounds ranging from carbohydrates to phenols varying in chemical and structural composition like levoglusogan, gluten, tannin, syringol, pectin and leucine falling within different compound categories (carbohydrates, amino acids, proteins, phenols, etc.) as well as soil samples. Pyrolysis yields of prominent specific functional groups, like aliphatics (C-H stretching at 2930?cm?1) and C=C aromatics (1510?cm?1), varied with pyrolysis temperature, heating rate and time. The preferred settings for high pyrolysis yield and minimized secondary reactions were obtained at a pyrolysis temperature of 700?°C, heating rate of 20?°C?ms?1 and heating time of 30?s. The suitability of Py-MIRS to detect changes in SOM composition was evaluated by comparing Py-MIRS results to Diffuse Reflectance Fourier Transform mid-Infrared Spectroscopy (DRIFTS) results. Soil samples taken from the Static Fertilization Experiment, Bad Lauchst?dt, Germany (Chernozem) revealed a major SOM contribution of the peak at 1750?cm?1 (C=O), followed by peaks at 950 (C-H), 1510 (C=C), 1176 (C-H, O-H) cm?1, with smaller contributions from the 2930 (C-H) and 3015 (CH4) cm?1 peaks, apart from a dominant CO2 peak. Using the preferred pyrolysis settings, Py-MIRS as well as DRIFTS results further indicated that soils receiving organic (e.g. farmyard manure) inputs were highly enriched in aliphatic groups, while their absence favored the accumulation of carboxyl and aromatic groups as well as polysaccharides. Py-MIRS allowed via semi-quantification of pyrolysis products a rapid monitoring of SOM bulk chemistry with a high degree of reproducibility. It was concluded that Py-MIRS represents a fast, effective and reproducible technique to characterize changes in the SOM bulk chemistry as a result of management practices. It also allows to minimize acknowledged constraints of other analytical techniques used to characterize SOM bulk chemistry such as mineral interferences and associated secondary reactions.Nürnberg, D.J., Morton, J., Santabarbara, S., Telfer, A., Joliot, P., Antonaru, L.A., Ruban, A.V., Cardona, T., Krausz, E., Boussac, A., Fantuzzi, A., Rutherford, A.W., 2018. Photochemistry beyond the red limit in chlorophyll f–containing photosystems. Science 360, 1210-1213.. Photosystems I and II convert solar energy into the chemical energy that powers life. Chlorophyll a photochemistry, using red light (680 to 700 nm), is near universal and is considered to define the energy “red limit” of oxygenic photosynthesis. We present biophysical studies on the photosystems from a cyanobacterium grown in far-red light (750 nm). The few long-wavelength chlorophylls present are well resolved from each other and from the majority pigment, chlorophyll a. Charge separation in photosystem I and II uses chlorophyll f at 745 nm and chlorophyll f (or d) at 727 nm, respectively. Each photosystem has a few even longer-wavelength chlorophylls f that collect light and pass excitation energy uphill to the photochemically active pigments. These photosystems function beyond the red limit using far-red pigments in only a few key positions.Editor's Summary: Lower-energy photons do the work, too. Plants and cyanobacteria use chlorophyll-rich photosystem complexes to convert light energy into chemical energy. Deep-water organisms do not receive the full spectrum of light and have adaptations to take advantage of longer-wavelength photons. Nürnberg et al. studied photosystem complexes from cyanobacteria grown in the presence of far-red light. The authors identified the primary donor chlorophyll as one of a few chlorophyll molecules in the red light–adapted enzymes that were chemically altered to shift their absorption spectrum. Kinetic measurements demonstrated that far-red light is capable of directly driving water oxidation, despite having less energy than the red light used by most photosynthetic organisms.Ohira, S.-I., Kaneda, K., Matsuzaki, T., Mori, S., Mori, M., Toda, K., 2018. Universal HPLC detector for hydrophilic organic compounds by means of total organic carbon detection. Analytical Chemistry 90, 6461-6467. quantifications are achieved by comparison of the signals obtained with the sample to those from a standard. Thus, the purity and stability of the standard are key in chemical analysis. Furthermore, if an analyte standard cannot be obtained, quantification cannot be achieved, even if the chemical structures are identified by a qualification method (e.g., high-resolution mass spectrometry). Herein, we describe a universal and analyte standard-free detector for aqueous-eluent-based high-performance liquid chromatography. This universal carbon detector (UCD) was developed based on total organic carbon detection. Separated analytes were oxidized in-line and converted to carbon dioxide (CO2). Generated CO2 was transferred into the gas phase and collected into ultrapure water, which was followed by conductivity detection. The system can be applied as a HPLC detector that does not use an organic solvent as an eluent. The system can be calibrated with a primary standard of sodium bicarbonate for organic compounds. The universality and quantification were evaluated with organic compounds, including organic acids, sugars, and amino acids. Furthermore, the system was successfully applied to evaluation of the purity of formaldehyde in formalin solution, and determination of sugars in juices. The results show the universal carbon detector has good universality and can quantify many kinds of organic compounds with a single standard such as sodium bicarbonate.Olaru, R., Krézsek, C., Rainer, T.M., Ungureanu, C., Turi, V., Ionescu, G., Tari, G., 2018. 3D basin modelling of Oligocene – Miocene Maikop source rocks offshore Romania and in the western Black Sea. Journal of Petroleum Geology 41, 351-365. discoveries in the Western Black Sea have proved the presence of both thermogenic and biogenic petroleum systems. The presence of Tertiary biomarkers in oils from the Romanian part of the Western Black Sea sub‐basin, and correlation with Oligocene to Lower Miocene black shales, suggests that the thermogenic petroleum system is sourced mainly by the Oligocene – Miocene Maikop Group. Older source rocks may also be present locally in other parts of the sub‐basin, but their contribution is currently poorly understood. This paper presents the results of 3D basin modelling which was intended to evaluate charge models for prospects in the Western Black Sea sourced by the Maikop Group shales. The model is built on the regional‐scale interpretation of recently acquired, long‐offset 2D reflection seismic data, and was calibrated with proprietary and published well, geochemical and temperature data. The sensitivity of the thermal models on source maturity was tested. The basin models investigated two end‐member heat‐flow scenarios, “hot” and “cold”. Whereas the “hot” model more successfully reproduces the field and well data in shelfal areas of the Western Black Sea, the “cold” model is considered to be more valid for deeper‐water areas. Hydrocarbon expulsion maps were calculated for both scenarios at key stratigraphic levels, with preferential migration routes identified. The results of the basin modelling suggest that the most likely source rocks for the oils in accumulations offshore Romania are located in the mid‐Maikop Group (Upper Rupelian? to Chattian). Core data from offshore wells indicate that the source rocks consist of black shales with fair to good oil generation potential (TOC ～ 0.5 to 4.5%, HI <600 mg/g TOC, and mixed Type II/III kerogen). At the present day, these shales are in the early oil window offshore Romania to the SE of the producing fields, and in the wet gas window further to the east. Hydrocarbon expulsion from the mid‐Maikop interval began during the Middle Miocene, but significant volumes of liquids were generated only in the Late Miocene with the peak of expulsion not yet reached. Charging the accumulations on the Romanian Shelf requires lateral migration along the base‐Oligocene unconformity over distances of about 20–50 km. In addition, hydrocarbons have charged underlying Eocene and Cretaceous reservoir sections by lateral downward migration, filling structural traps and spilling over to higher structural levels. The results highlight the underexplored potential associated with the Maikop Group in the Western Black Sea. Orberger, B., Delarue, V., Rodriguez, C., Salaün, A., Wallmach, T., Wirth, R., Boussafir, M., Dreux, G., Lafon, S., Schreiber, A., 2018. In-situ analyses of carbonaceous matter in manganiferous black shales: Analytical proxies and implication for ore processing. Minerals Engineering 125, 83-93. matter is generally known to be problematic for metal recovery during metallurgical processing of black shales. In particularly, metal upgrading during beneficiation prior to (bio-) hydrometallurgical and/or pyrometallurgical processing is hindered by the presence of abundant carbonaceous matter (CM). This study presents the characterization of CM and mineral bound carbonaceous matter (CMP) in three manganese carbonate-rich shales hosting 6–8?wt% total organic carbon. Non-destructive methods, such as incident light microscopy, scanning electron (SEM) and focused-ion-beam-transmission electron microscopy (FIB-TEM), QEMSCAN and electron microprobe, were used to show that free CM is adsorbed onto illite-smectite surfaces. This form of CM ranges in grain size from sub-micrometer up to ≈100?μm. The most efficient method to show the illite-smectite association is SEM and for quantification of this association, QEMSCAN should be used. Mineral-bound carbonaceous matter may be relicts of extrapolymers (pyrite and/or carbonate) and needs characterization using FIB-TEM. The quantity of CM can then be estimated by a rough calculation as the difference between the total organic carbon (Rock Eval) and the free carbon calculated from normative mineral compositions based on X-ray Fluorescence (XRF) and X-ray-Diffraction (XRD) analyses. The mineral bound CM could not be detected by QEMSCAN under conventional analytical conditions. We estimated that about 85% of the CM in the test samples was adsorbed on mineral surfaces and about 15% was bound to minerals. The physical protection of the CM by clays, and the morphological and density differences between pyrite, carbonates and biochemically-bound CM in pyrite/carbonates needs to be taken into consideration in the process design.Oron, S., Abramovich, S., Almogi-Labin, A., Woeger, J., Erez, J., 2018. Depth related adaptations in symbiont bearing benthic foraminifera: New insights from a field experiment on Operculina ammonoides. Scientific Reports 8, Article 9560. benthic foraminifera (LBF) are marine calcifying protists that commonly harbor algae as symbionts. These organisms are major calcium carbonate producers and important contributors to primary production in the photic zones. Light is one of the main known factors limiting their distribution, and species of this group developed specific mechanisms that allow them to occupy different habitats across the light gradient. Operculina ammonoides (Gronovius, 1781) is a planispiral LBF that has two main shell morphotypes, thick involute and flat evolute. Earlier studies suggested morphologic changes with variation in water depth and presumably light. In this study, specimens of the two morphotypes were placed in the laboratory under artificial low light and near the sea floor at depths of 15?m, 30?m, and 45?m in the Gulf of Aqaba-Eilat for 23 days. Differences in growth and symbionts content were evaluated using weight, size, and chlorophyll a. Our results show that O. ammonoides exhibit morphological plasticity when constructing thinner chambers after relocation to low light conditions, and adding more weight per area after relocation to high light conditions. In addition, O. ammonoides exhibited chlorophyll content adaptation to a certain range of light conditions, and evolute specimens that were acclimatized to very low light did not survive relocation to a high light environment, possibly due to photo-oxidative stress.Orsini, S., Yadav, A., Dilillo, M., McDonnell, L.A., Bonaduce, I., 2018. Characterization of degraded proteins in paintings using bottom-up proteomic approaches: New strategies for protein digestion and analysis of data. Analytical Chemistry 90, 6403-6408. hydrolysis assisted by microwave irradiation has been proposed as an alternative method for the analysis of proteins in highly insoluble matrices. In this work, chemical hydrolysis was applied for the first time to detect degraded proteins from paintings and polychromies. To evaluate the performance of this approach, the number of identified peptides, protein sequence coverage (%), and PSMs were compared with those obtained using two trypsin-based proteomics procedures used for the analysis of samples from cultural heritage objects. It was found that chemical hydrolysis allowed the successful identification of all proteinaceous materials in all paint samples analyzed except for egg proteins in one extremely degraded sample. Moreover, in one sample, casein was only identified by chemical digestion. In general, chemical hydrolysis identified more peptides, more PSM’s, and greater sequence coverage in the samples containing caseins, and often also in animal glue, highlighting the great potential of this approach for the rapid digestion and identification of insoluble and degraded proteins from the field of the cultural heritage.Othman, F., Yu, M., Kamali, F., Hussain, F., 2018. Fines migration during supercritical CO2 injection in sandstone. Journal of Natural Gas Science and Engineering 56, 344-357. formations are widely considered for underground sequestration of CO2. During CO2 injection, fines migration can cause pore blockage, which reduces sandstone permeability and CO2 injectivity. To better the understanding of the mechanism of fines migration during CO2 injection, this study characterizes the fines mobilized.This paper presents a CO2 injection experiment with detailed characterization of the rock and fluids produced. A Berea sandstone core sample is used. To characterize the core sample, X-Ray powder Diffraction (XRD), X-Ray Fluorescence (XRF), and Scanning Electron Microscopy (SEM) analyses are performed. The core receives injection first of brine (10?g/l NaCl), then of CO2-saturated brine, and finally of brine-saturated supercritical CO2 (scCO2). During the injection, pressure difference between the core's injection face and production face is recorded. Samples of produced water are used for calculating produced fines concentration and for ionic chromatography. Then fines are separated from the produced water samples for further characterization. After the experiment, SEM images of the core are taken and compared with the pre-injection images to assess fines migration. Energy Dispersive X-ray Spectroscopy (EDS) is run on the post-injection SEM images to identify the fines blocking the pores.SEM-EDS analysis of the produced fines and blocked pores in the core show that blockage is caused by clay, quartz, and cement. Ionic chromatography for produced water during CO2-saturated brine and brine-saturated scCO2 injection show an increase in the ions present in the intergranular cement of Berea core. This indicates that CO2-saturated brine dissolved the cement, resulting in dislodgement of clay and quartz particles, some of which blocked the pore space near the core production end and thereby reduced permeability.Pace, A., Bourillot, R., Bouton, A., Vennin, E., Braissant, O., Dupraz, C., Duteil, T., Bundeleva, I., Patrier, P., Galaup, S., Yokoyama, Y., Franceschi, M., Virgone, A., Visscher, P.T., 2018. Formation of stromatolite lamina at the interface of oxygenic–anoxygenic photosynthesis. Geobiology 16, 378-398. modern stromatolites, mineralization results from a complex interplay between microbial metabolisms, the organic matrix, and environmental parameters. Here, we combined biogeochemical, mineralogical, and microscopic analyses with measurements of metabolic activity to characterize the mineralization processes and products in an emergent (<18 months) hypersaline microbial mat. While the nucleation of Mg silicates is ubiquitous in the mat, the initial formation of a Ca‐Mg carbonate lamina depends on (i) the creation of a high‐pH interface combined with a major change in properties of the exopolymeric substances at the interface of the oxygenic and anoxygenic photoautotrophic layers and (ii) the synergy between two major players of sulfur cycle, purple sulfur bacteria, and sulfate‐reducing bacteria. The repetition of this process over time combined with upward growth of the mat is a possible pathway leading to the formation of a stromatolite. Pall, J., Zahirovic, S., Doss, S., Hassan, R., Matthews, K.J., Cannon, J., Gurnis, M., Moresi, L., Lenardic, A., Müller, R.D., 2018. The influence of carbonate platform interactions with subduction zone volcanism on palaeo-atmospheric CO2 since the Devonian. Climate of the Past 14, 857-870. CO2 liberated along subduction zones through intrusive/extrusive magmatic activity and the resulting active and diffuse outgassing influences global atmospheric CO2. However, when melts derived from subduction zones intersect buried carbonate platforms, decarbonation reactions may cause the contribution to atmospheric CO2 to be far greater than segments of the active margin that lacks buried carbon-rich rocks and carbonate platforms. This study investigates the contribution of carbonate-intersecting subduction zones (CISZs) to palaeo-atmospheric CO2 levels over the past 410 million years by integrating a plate motion and plate boundary evolution model with carbonate platform development through time. Our model of carbonate platform development has the potential to capture a broader range of degassing mechanisms than approaches that only account for continental arcs.Continuous and cross-wavelet analyses as well as wavelet coherence are used to evaluate trends between the evolving lengths of carbonate-intersecting subduction zones, non-carbonate-intersecting subduction zones and global subduction zones, and are examined for periodic, linked behaviour with the proxy CO2 record between 410?Ma and the present. Wavelet analysis reveals significant linked periodic behaviour between 60 and 40?Ma, when CISZ lengths are relatively high and are correlated with peaks in palaeo-atmospheric CO2, characterised by a 32–48?Myr periodicity and a ?～??8–12?Myr lag of CO2 peaks following CISZ length peaks. The linked behaviour suggests that the relative abundance of CISZs played a role in affecting global climate during the Palaeogene. In the 200–100?Ma period, peaks in CISZ lengths align with peaks in palaeo-atmospheric CO2, but CISZ lengths alone cannot be determined as the cause of a warmer Cretaceous–Jurassic climate. Nevertheless, across the majority of the Phanerozoic, feedback mechanisms between the geosphere, atmosphere and biosphere likely played dominant roles in modulating climate. Our modelled subduction zone lengths and carbonate-intersecting subduction zone lengths approximate magmatic activity through time, and can be used as input into fully coupled models of CO2 flux between deep and shallow carbon reservoirs.Panahi, H., Kobchenko, M., Meakin, P., Dysthe, D.K., Renard, F., 2018. In-situ imaging of fracture development during maturation of an organic-rich shale: Effects of heating rate and confinement. Marine and Petroleum Geology 95, 314-327. statistics and dynamics of fractures formed during the accelerated maturation of kerogen-rich shale was investigated by heating Green River Shale (R-8 unit, Piceance Basin, northwestern Colorado) core samples while 3D X-ray microtomographic images were acquired. Previous studies have shown that, when there was no confining stress, fractures formed while the kerogen contained in the shale matured, and the produced hydrocarbon was expelled through these fractures. In the present study, X-ray tomographic scans at multiple voxel sizes were conducted on similar samples during heating. In one experiment, the shale sample was tightly fitted in a non-porous ceramic tube to confine it while it was heated. Three unconfined samples were heated and then held at different final temperatures to investigate the effects of the gas production rate on fracturing. 3D image processing was used to survey fracture network development, and time-lapse 2D digital image correlation analysis was used to monitor the development of the displacement and strain fields. The results revealed that fracturing is strongly dependent on the heating rate and the final heating temperature. While most of the fractures were oriented more-or-less parallel to the bedding plane, some were strongly inclined relative to the bedding plane. The formation of inclined fractures is attributed primarily to the shape and orientation of a minority of the flake-like kerogen patches, and also to the effective stress field and fractured zones of weakness. A conceptual model is proposed to explain the dynamics of fluid expulsion and the associate fracturing behavior.Panasia, G., Philipp, B., 2018. LaoABCR, a novel system for oxidation of long-chain alcohols derived from SDS and alkane degradation in Pseudomonas aeruginosa. Applied and Environmental Microbiology 84, Article AEM.00626-00618.: The opportunistic pathogen Pseudomonas aeruginosa strain PAO1 is able to use a variety of organic pollutants as growth substrates, including the anionic detergent sodium dodecyl sulfate (SDS) and long-chain alkanes. While the enzymes initiating SDS and alkane degradation are well known, the subsequent enzymatic steps for degradation of the derived primary long-chain alcohols have not yet been identified. By evaluating genes specifically induced during growth with SDS, a gene cluster encoding a putative alcohol dehydrogenase (PA0364/LaoA), a probable inner membrane protein (PA0365/LaoB), and a presumable aldehyde dehydrogenase (PA0366/LaoC) was identified and designated the Lao (long-chain-alcohol/aldehyde-oxidation) system. Growth experiments with deletion mutants with SDS, 1-dodecanol, and alkanes revealed that LaoA and LaoB are involved in the degradation of primary long-chain alcohols. Moreover, detection of 1-dodecanol oxidation in cell extracts by activity staining revealed an interdependency of LaoA and LaoB for efficient 1-dodecanol oxidation. An in silico analysis yielded no well-characterized homologue proteins for LaoA and LaoB. Furthermore, a gene adjacent to the lao gene cluster encodes a putative transcriptional regulator (PA0367/LaoR). A laoR deletion mutant exhibited constitutive expression of LaoA and LaoB, indicating that LaoR is a repressor for the expression of laoABC. Taken together, these results showed that the proteins LaoA and LaoB constitute a novel oxidation system for long-chain alcohols derived from pollutants. Importance: The versatile and highly adaptive bacterium Pseudomonas aeruginosa is able to colonize a variety of habitats, including anthropogenic environments, where it is often challenged with toxic compounds. Its ability to degrade such compounds and to use them as growth substrates can significantly enhance spreading of this opportunistic pathogen in hygienic settings, such as clinics or water distribution systems. Thus, knowledge about the metabolism of P. aeruginosa can contribute to novel approaches for preventing its growth and reducing nosocomial infections. As the Lao system is important for the degradation of two different classes of pollutants, the identification of these novel enzymes can be a useful contribution for developing effective antibacterial strategies. Pandey, R., Harpalani, S., 2018. An imaging and fractal approach towards understanding reservoir scale changes in coal due to bioconversion. Fuel 230, 282-297. enhanced coalbed methane (MECBM) aims to replicate the natural process of microbial methane generation in coal under in situ conditions. Considerable work has been reported over the years to optimize the associated microbial geo-chemistry. However, there is very little insight with regards to changes in the physical structure of coal due to bioconversion, and its impact on fluid flow properties. This paper presents the result of an image and fractal-based approach used to evaluate the changes in physical properties of coal. Samples of coal treated over 30, 60 and 120?days respectively were imaged before and after bioconversion. The results revealed that coal bioconversion resulted in swelling of the coal matrix. Cleats narrower than 5??m reduced in its width post-bioconversion. A 77% drop in the permeability of coal is expected from the obtained results. Bioconversion also resulted in separation of thin layers of coal flakes from the coal surface, serving as a potential source of fines. Fractal analysis of the images revealed a decrease in the fractal dimension post bioconversion, which is in agreement with the previously reported studies, thus corroborating the variations in sorption-trends observed due to bioconversion. Additionally, the methodology to determine the fractal dimension via two-dimensional image processing was modified to improve its accuracy, and remove the dependency of the dimension to the scale of the obtained images. Bioconversion also resulted in formation of new pores/fractures. Shorter treatment duration resulted in nanometer-scale discontinuous pores, which do not contribute to Darcian flow. Longer treatment periods resulted in sub-micron wide continuous pores. Also, few larger fractures (>5??m wide) saw an increase in its aperture post-treatment. This opens up new avenues, such as, utilizing artificially induced fracturing techniques to enhance biogenic methane production in future.Pang, Z., Lyu, X., Zhang, F., Wu, T., Gao, Z., Geng, Z., Luo, C., 2018. The macroscopic and microscopic analysis on the performance of steam foams during thermal recovery in heavy oil reservoirs. Fuel 233, 166-176. heavy oil reservoirs, steam channeling and steam override seriously decrease oil production and the ultimate oil recovery during steam flooding. Aiming at the two problems, some experiments were carried out to analyze the EOR mechanisms through injecting foaming agents along with steam injection in heavy oil reservoirs. An orthogonal method was employed to analyze the multiple factors on foam’s properties to optimize foaming agent for steam injection. Then a novel 2D-visualization experiment was carried out to quantitatively study the characteristics of steam channeling and the variation of sweep efficiency during steam or steam foams flooding. Based on the experimental results, many bubble’s characteristics, such as migration, retention, regeneration and etc., were analyzed through the macroscopic and microscopic perspectives. The experimental results show that the Jamin effect increases the flow resistance of steam-phase in porous media to obviously enlarge the macro sweep efficiency and effectively increase micro oil displacement efficiency. On a macroscopic level, because of the unique structure, foams decrease steam override or steam channeling to improve sweep efficiency; on a microscopic level, due to the expansion effect of gas-phase, bubbles can desquamate the oil film on the pore wall and even the oil drop in the blind pore to decrease the residual oil saturation. In our experiments, the ultimate recovery of steam flooding can only reach 48.48%. However, the ultimate recovery of steam foams can reach 59.95%, which is 11.47% higher than steam flooding.Panyushkina, A.E., Tsaplina, I.A., Kondrat’eva, T.F., Belyi, A.V., Bulaev, A.G., 2018. Physiological and morphological characteristics of acidophilic bacteria Leptospirillum ferriphilum and Acidithiobacillus thiooxidans, members of a chemolithotrophic microbial consortium. Microbiology 87, 326-338. thermoacidophilic consortium of chemolithotrophic microorganisms oxidizing the concentrate of high-pyrrhotite pyrite?arsenopyrite ore at 38–40°C was isolated. The most active members of the consortium were identified as Leptospirillum ferriphilum, Acidithiobacillus thiooxidans, Ferroplasma acidiphilum, and Sulfobacillus thermotolerans. Leptospirillum and Thiobacillus species were the most numerous members of the consortium and had the highest activity of ferrous iron and sulfur oxidation, respectively. The optimal temperature values for the growth of both isolates were within 35–38°C. The optimal ranges of initial pH were 1.0–1.2 and 1.75–1.85 for leptospirilla and 1.7–3.3 for thiobacilli with the pH optimum of 1.9. Significant polymorphism and specific cyclic growth with formation of vibrios, spirilla, rods with different end shape, spiral filaments, numerous “pseudococci,” and densely packed spiral filaments surrounded by a sheath were revealed for the Leptospirillum isolate. Two latter morphoforms of L. ferriphilum were not previously described. Differences in ability of the morphoforms to oxidize Fe2+ were revealed. For the first time, the possibility of growth in the presence of organic substances was demonstrated for A. thiooxidans. The rates of growth and substrate oxidation, cell size, and the maximal cell yield decreased insignificantly in comparison with the lithoautotrophic strain. Original Russian Text ? A.E. Panyushkina, I.A. Tsaplina, T.F. Kondrat’eva, A.V. Belyi, A.G. Bulaev, 2018, published in Mikrobiologiya, 2018, Vol. 87, No. 3.Paparella, I., Palci, A., Nicosia, U., Caldwell, M.W., 2018. A new fossil marine lizard with soft tissues from the Late Cretaceous of southern Italy. Royal Society Open Science 5, Article 172411. new marine lizard showing exceptional soft tissue preservation was found in Late Cretaceous deposits of the Apulian Platform (Puglia, Italy). Primitivus manduriensis gen. et sp. nov. is not only the first evidence of the presence of dolichosaurs in a southern Italian Carbonate Platform, filling a palaeogeographic gap in the Mediterranean Tethys, but also extends the range of this group to the upper Campanian–lower Maastrichtian. Our parsimony analysis recovers a monophyletic non-ophidian pythonomorph clade, including Tetrapodophis amplectus at the stem of Mosasauroidea?+?Dolichosauridae, which together represent the sister group of Ophidia (modern and fossil snakes). Based on Bayesian inference instead, Pythonomorpha is monophyletic, with Ophidia representing the more deeply nested clade, and the new taxon as basal to all other pythonomorphs. Primitivus displays a fairly conservative morphology in terms of both axial elongation of the trunk and limb reduction, and the coexistence of aquatic adaptations with features hinting at the retention of the ability to move on land suggests a semi-aquatic lifestyle. The exceptional preservation of mineralized muscles, portions of the integument, cartilages and gut content provides unique sources of information about this extinct group of lizards. The new specimen may represent local persistence of a relict dolichosaur population until almost the end of the Cretaceous in the Mediterranean Tethys, and demonstrates the incompleteness of our knowledge of dolichosaur temporal and spatial distributions.Parastar, H., Garreta‐Lara, E., Campos, B., Barata, C., Lacorte, S., Tauler, R., 2018. Chemometrics comparison of gas chromatography with mass spectrometry and comprehensive two‐dimensional gas chromatography with time‐of‐flight mass spectrometry Daphnia magna metabolic profiles exposed to salinity. Journal of Separation Science 41, 2368-2379. performances of gas chromatography with mass spectrometry and of comprehensive two‐dimensional gas chromatography with time‐of‐flight mass spectrometry are examined through the comparison of Daphnia magna metabolic profiles. Gas chromatography with mass spectrometry and comprehensive two‐dimensional gas chromatography with mass spectrometry were used to compare the concentration changes of metabolites under saline conditions. In this regard, a chemometric strategy based on wavelet compression and multivariate curve resolution–alternating least squares is used to compare the performances of gas chromatography with mass spectrometry and comprehensive two‐dimensional gas chromatography with time‐of‐flight mass spectrometry for the untargeted metabolic profiling of Daphnia magna in control and salinity‐exposed samples. Examination of the results confirmed the outperformance of comprehensive two‐dimensional gas chromatography with time‐of‐flight mass spectrometry over gas chromatography with mass spectrometry for the detection of metabolites in D. magna samples. The peak areas of multivariate curve resolution–alternating least squares resolved elution profiles in every sample analyzed by comprehensive two‐dimensional gas chromatography with time‐of‐flight mass spectrometry were arranged in a new data matrix that was then modeled by partial least squares discriminant analysis. The control and salt‐exposed daphnids samples were discriminated and the most relevant metabolites were estimated using variable importance in projection and selectivity ratio values. Salinity de‐regulated 18 metabolites from metabolic pathways involved in protein translation, transmembrane cell transport, carbon metabolism, secondary metabolism, glycolysis, and osmoregulation. Park, C., Park, W., 2018. Survival and energy producing strategies of alkane degraders under extreme conditions and their biotechnological potential. Frontiers in Microbiology 9, 1081. doi: 1010.3389/fmicb.2018.01081. petroleum-polluted areas are considered as extreme environments because of co-occurrence of low and high temperatures, high salt, and acidic and anaerobic conditions. Alkanes, which are major constituents of crude oils, can be degraded under extreme conditions, both aerobically and anaerobically by bacteria and archaea of different phyla. Alkane degraders possess exclusive metabolic pathways and survival strategies, which involve the use of protein and RNA chaperones, compatible solutes, biosurfactants, and exopolysaccharide production for self-protection during harsh environmental conditions such as oxidative and osmotic stress, and ionic nutrient-shortage. Recent findings suggest that the thermophilic sulfate-reducing archaeon Archaeoglobus fulgidus uses a novel alkylsuccinate synthase for long-chain alkane degradation, and the thermophilic Candidatus Syntrophoarchaeum butanivorans anaerobically oxidizes butane via alkyl-coenzyme M formation. In addition, gene expression data suggest that extremophiles produce energy via the glyoxylate shunt and the Pta-AckA pathway when grown on a diverse range of alkanes under stress conditions. Alkane degraders possess biotechnological potential for bioremediation because of their unusual characteristics. This review will provide genomic and molecular insights on alkane degraders under extreme conditions.Parr, M.K., Wüst, B., Teubel, J., Joseph, J.F., 2018. Splitless hyphenation of SFC with MS by APCI, APPI, and ESI exemplified by steroids as model compounds. Journal of Chromatography B 1091, 67-78. systematic evaluation of splitless hyphenation of supercritical fluid chromatography (SFC) with mass spectrometry (MS) was performed using different techniques for ambient pressure ionization. Interfaces commonly known from HPLC-MS/MS, i.e. electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and atmospheric pressure photo ionization (APPI), were tested for their suitability in SFC-MS/MS. A triple quadrupole MS was used for data evaluation in a targeted multi-analyte design using endogenous steroids as model compounds. Individual optimization of the ionization parameters was performed in multi-dimensional design for best support of ionization in all three techniques. A post-column make-up was used to avoid analyte precipitation in the transfer capillary but also to support ionization independently from mobile phase composition. Buffer choice and concentration as well as temperature were found crucial in ESI and APCI. Best results for the multi-analyte method were obtained in both techniques using ammonium fluoride as make-up buffer. Instead of buffer solutions different organic solvents were used as dopants in APPI to support ionization. The mobile phase constituent isopropanol was already found to support ionization in APPI, however, for many analytes the addition of toluene resulted in superior results in terms of intensity. Comparing the optimized methods in terms of limit of detection (LOD), limit of quantification (LOQ), and sensitivity (slope of calibration curve) ESI was the best choice for the multiple analyte design. Only a few analytes resulted in a different optimum ionization, if focused on separately. In terms of linear dynamic range, APCI and APPI proved superior to ESI, where calibration over the whole range of concentrations (from LOD up to 5000?pg???μL?1) required quadratic regression.Partensky, F., Six, C., Ratin, M., Garczarek, L., Vaulot, D., Probert, I., Calteau, A., Gourvil, P., Marie, D., Grébert, T., Bouchier, C., Le Panse, S., Gachenot, M., Rodríguez, F., Garrido, J.L., 2018. A novel species of the marine cyanobacterium Acaryochloris with a unique pigment content and lifestyle. Scientific Reports 8, Article 9142. characterized members of the ubiquitous genus Acaryochloris share the unique property of containing large amounts of chlorophyll (Chl) d, a pigment exhibiting a red absorption maximum strongly shifted towards infrared compared to Chl a. Chl d is the major pigment in these organisms and is notably bound to antenna proteins structurally similar to those of Prochloron, Prochlorothrix and Prochlorococcus, the only three cyanobacteria known so far to contain mono- or divinyl-Chl a and b as major pigments and to lack phycobilisomes. Here, we describe RCC1774, a strain isolated from the foreshore near Roscoff (France). It is phylogenetically related to members of the Acaryochloris genus but completely lacks Chl d. Instead, it possesses monovinyl-Chl a and b at a b/a molar ratio of 0.16, similar to that in Prochloron and Prochlorothrix. It differs from the latter by the presence of phycocyanin and a vestigial allophycocyanin energetically coupled to photosystems. Genome sequencing confirmed the presence of phycobiliprotein and Chl b synthesis genes. Based on its phylogeny, ultrastructural characteristics and unique pigment suite, we describe RCC1774 as a novel species that we name Acaryochloris thomasi. Its very unusual pigment content compared to other Acaryochloris spp. is likely related to its specific lifestyle.Parthipan, P., Elumalai, P., Narenkumar, J., Machuca, L.L., Murugan, K., Karthikeyan, O.P., Rajasekar, A., 2018. Allium sativum (garlic extract) as a green corrosion inhibitor with biocidal properties for the control of MIC in carbon steel and stainless steel in oilfield environments. International Biodeterioration & Biodegradation 132, 66-73. the present study, the effectiveness of garlic extract to inhibit the bio-corrosion of carbon steel API 5LX (CS) and stainless steel 316 (SS) in the presence of Bacillus subtilis A1 and Streptomyces parvus B7 was estimated. The antibacterial activity of the garlic extract (GAE) was tested; 100?ppm of the GAE was identified as the minimal inhibitory concentration for bacterial growth. Weight loss and electrochemical studies including linear polarization and AC impedance along with surface analysis were used to examine the corrosion inhibition efficiency (IE) for both metals in the presence of GAE. The strains A1, B7 and their mixed consortium caused severe corrosion to both metals. In the presence of GAE the IE for abiotic system was about 81?±?3% and 75?±?3%, while in the presence of the mixed consortium the IE was 72?±?3% and 69?±?3% for CS and SS, respectively. Gas chromatography mass spectrum analysis of GAE indicated that GAE contains a sulphur rich compound which plays a key role in the inhibition of both bacterial development and corrosion. This is the first time garlic extract is proposed as a green corrosion inhibitor with biocidal activity to control biocorrosion in hypersaline corrosive environment containing microorganisms.Pasquini, C., 2018. Near infrared spectroscopy: A mature analytical technique with new perspectives – A review. Analytica Chimica Acta 1026, 8-36. decade's advances and modern aspects of near infrared spectroscopy are critically examined and reviewed. Innovative instrumentation, highlighted by portable and imaging instruments, chemometrics data multivariate processing, and new and valuable applications are presented and discussed. Because of these advances, this mature analytical technique is continually experiencing renewed interest. The drawbacks and misuses of the technique and its supporting mathematical tools are also addressed. The principal achievements in the field are shown in a critical manner, in order to understand why the technique has found intensive application in the most diverse and modern areas of analytical importance during the last ten years.Patel, H., Shah, S., Ahmed, R., Ucan, S., 2018. Effects of nanoparticles and temperature on heavy oil viscosity. Journal of Petroleum Science and Engineering 167, 819-828. objective of this research is to investigate the efficacy of nanoparticles in reducing the viscosity of heavy oil. In this study, three types of metal oxide nanoparticles (CuO, Fe2O3, and NiO) are employed, and their effect on heavy oil viscosity is examined at three different concentrations (0.05, 0.1, and 0.5?wt.% of oil). For all test fluids, rheological measurements were obtained at four different temperatures ranging from 27 to 71?°C. The experimental work is conducted with two extremely viscous heavy oil samples having viscosity of approximately 77 and 350?Pas?at ambient temperature. This study is unprecedented in terms of viscosity of heavy oil samples investigated. The heavy oil samples used in this study are 9–40 times more viscous than those used in previous similar studies.The addition of nanoparticles resulted in a notable reduction in viscosity of both heavy oil samples. For each type of nanoparticles, 50–70% viscosity reduction was observed. The level of viscosity reduction is sensitive to the types of nanoparticles, their concentration, and fluid temperature. Moreover, the results indicate existence of an optimum concentration of nanoparticles at which maximum viscosity reduction occurs. This optimum concentration is a function of the metal type and fluid temperature.To explain observed viscosity alteration behavior, the paper provides a theoretical overview of various molecular-level physical and chemical interactions between nanoparticles and heavy oil. Additionally, the study presents a new heavy oil viscosity data and delineates some of the challenges associated with viscosity measurement of heavy oil.This research provides valuable information for future rheological and core-flooding studies involving nanoparticle stabilized solvent-based emulsions. Besides, remarkable viscosity reduction obtained in this work reinforces the industry's interest in developing an economically feasible nanoparticle-based technique and helps to solve real problems in the field.Peng, J., Pang, X., Shi, H., Peng, H., Xiao, S., 2018. Hydrocarbon-generation potential of Upper Eocene Enping Formation mudstones in the Huilu area, northern Pearl River Mouth Basin, South China Sea. American Association of Petroleum Geologists Bulletin 102, 1323-1342. Eocene Enping Formation mudstones in the Pearl River Mouth Basin, South China Sea, which formed during a lake-flooding event, are one of the most important sets of cap rocks in the basin. However, the generation potential (GP) of Enping Formation mudstones remains poorly understood and controversial. Despite a lack of documentation, these mudstones are presumed to have the potential to generate hydrocarbons. In this study, new organic geochemical data for these mudstones are provided based on several new wells drilled into Eocene strata in the Huilu area, northern Pearl River Mouth Basin, which illustrate their hydrocarbon GP. Total organic carbon content ranges from 0.55 to 3.3 wt. % (mean, 1.31 wt. %) with kerogens dominated by type III organic matter (OM) derived from terrigenous plant material. The Zhuqiong II movement, a rifting episode that occurred during the late Eocene (ca. 38 Ma), was associated with the introduction of a large quantity of terrigeneous higher plants by rivers that led to type III OM accumulation and preservation of Enping Formation mudstones. Rapid transverse facies changes led to the geochemical heterogeneity of the source rocks. The OM in these rocks reached an early–midmature stage in uplifted areas (vitrinite reflectance [Ro] = 0.5%–1.0%) and a late–mature stage in sags (Ro =1.0%–1.3%), stages wherein hydrocarbons can be generated. Therefore, the Enping Formation mudstones may have had the potential to generate hydrocarbons, especially gas, and hence deserve attention in future exploration.Perazzo, A., Tomaiuolo, G., Preziosi, V., Guido, S., 2018. Emulsions in porous media: From single droplet behavior to applications for oil recovery. Advances in Colloid and Interface Science 256, 305-325. are suspensions of droplets ubiquitous in oil recovery from underground reservoirs. Oil is typically trapped in geological porous media where emulsions are either formed in situ or injected to elicit oil mobilization and thus enhance the amount of oil recovered. Here, we briefly review basic concepts on geometrical and wetting features of porous media, including thin film stability and fluids penetration modes, which are more relevant for oil recovery and oil-contaminated aquifers. Then, we focus on the description of emulsion flow in porous media spanning from the behaviour of single droplets to the collective flow of a suspension of droplets, including the effect of bulk and interfacial rheology, hydrodynamic and physico-chemical interactions. Finally, we describe the particular case of emulsions used in underground porous media for enhanced oil recovery, thereby discussing some perspectives of future work. Although focused on oil recovery related topics, most of the insights we provide are useful towards remediation of oil-contaminated aquifers and for a basic understanding of emulsion flow in any kind of porous media, such as biological tissues.Percival, L.M.E., Davies, J.H.F.L., Schaltegger, U., De Vleeschouwer, D., Da Silva, A.C., F?llmi, K.B., 2018. Precisely dating the Frasnian–Famennian boundary: implications for the cause of the Late Devonian mass extinction. Scientific Reports 8, Article 9578. Frasnian–Famennian boundary records one of the most catastrophic mass extinctions of the Phanerozoic Eon. Several possible causes for this extinction have been suggested, including extra-terrestrial impacts and large-scale volcanism. However, linking the extinction with these potential causes is hindered by the lack of precise dating of either the extinction or volcanic/impact events. In this study, a bentonite layer in uppermost-Frasnian sediments from Steinbruch Schmidt (Germany) is re-analysed using CA-ID-TIMS U-Pb zircon geochronology in order to constrain the date of the Frasnian–Famennian extinction. A new age of 372.36?±?0.053?Ma is determined for this bentonite, confirming a date no older than 372.4?Ma for the Frasnian–Famennian boundary, which can be further constrained to 371.93–371.78?Ma using a pre-existing Late Devonian age model. This age is consistent with previous dates, but is significantly more precise. When compared with published ages of the Siljan impact crater and basalts produced by large-scale volcanism, there is no apparent correlation between the extinction and either phenomenon, not clearly supporting them as a direct cause for the Frasnian–Famennian event. This result highlights an urgent need for further Late Devonian geochronological and chemostratigraphic work to better understand the cause(s) of this extinction.Peter, S., Sobek, S., 2018. High variability in iron-bound organic carbon among five boreal lake sediments. Biogeochemistry 139, 19-29. both stable carbon sinks and greenhouse gas sources, boreal lake sediments represent significant players in carbon (C) cycling. The release of dissolved organic carbon (DOC) into anoxic water is a widespread phenomenon in boreal lakes with impact on sediment C budgets. The association of OC with iron (Fe) is assumed to play an important role for this anoxic OC release via the dissimilatory reduction of Fe, but also to influence the stabilization of OC in sediments. To investigate the role of Fe–OC association for OC dynamics in different boreal lake sediments, we compared the content of Fe-bound OC [Fe–OC, defined as citrate bicarbonate dithionite (CBD) extractable OC] and the extent of reductive dissolution of solid-phase Fe and OC at anoxia. We found high among-lake variability in Fe–OC content, and while the amount of Fe–OC was high in three of the lakes (980–1920??mol?g?1), the overall contribution of Fe–OC to the sediment OC pool in all study lakes was not higher than 11%. No linkages between the amount of the Fe–OC pool and lake or sediment characteristics (e.g., pH, DOC concentration, sediment OC content, C:N ratio) could be identified. The observed release of OC from anoxic sediment may be derived from dissolution of Fe–OC in the lake sediments with high Fe–OC, but in other lake sediments, OC release during anoxia exceeded the sediment Fe–OC pool, indicating low contribution of reductive Fe dissolution to OC release from these lake sediments. The range of the investigated boreal lakes reflects the high variability in the size of the sediment Fe–OC pool (0–1920??mol?g?1) and CBD-extractable Fe (123–4050??mol?g?1), which was not mirrored in the extent of reductive dissolution of Fe (18.9–84.6??mol?g?1) and OC (1080–1700??mol?g?1) during anoxia, suggesting that Fe-bound OC may play a minor role for sediment OC release in boreal lakes. However, studies of redox-related OC cycling in boreal lake sediments should consider that the amount of Fe–OC can be high in some lakes.Phan, D.C., Goodwin Jr, D.G., Frank, B.P., Bouwer, E.J., Fairbrother, D.H., 2018. Biodegradability of carbon nanotube/polymer nanocomposites under aerobic mixed culture conditions. Science of The Total Environment 639, 804-814. properties and commercial viability of biodegradable polymers can be significantly enhanced by the incorporation of carbon nanotubes (CNTs). The environmental impact and persistence of these carbon nanotube/polymer nanocomposites (CNT/PNCs) after disposal will be strongly influenced by their microbial interactions, including their biodegradation rates. At the end of consumer use, CNT/PNCs will encounter diverse communities of microorganisms in landfills, surface waters, and wastewater treatment plants. To explore CNT/PNC biodegradation under realistic environmental conditions, the effect of multi-wall CNT (MWCNT) incorporation on the biodegradation of polyhydroxyalkanoates (PHA) was investigated using a mixed culture of microorganisms from wastewater. Relative to unfilled PHA (0% w/w), the MWCNT loading (0.5–10% w/w) had no statistically significant effect on the rate of PHA matrix biodegradation. Independent of the MWCNT loading, the extent of CNT/PNC mass remaining closely corresponded to the initial mass of CNTs in the matrix suggesting a lack of CNT release. CNT/PNC biodegradation was complete in approximately 20?days and resulted in the formation of a compressed CNT mat that retained the shape of the initial CNT/PNC. This study suggests that although CNTs have been shown to be cytotoxic towards a range of different microorganisms, this does not necessarily impact the biodegradation of the surrounding polymer matrix in mixed culture, particularly in situations where the polymer type and/or microbial population favor rapid polymer biodegradation.Philippot, P., ?vila, J.N., Killingsworth, B.A., Tessalina, S., Baton, F., Caquineau, T., Muller, E., Pecoits, E., Cartigny, P., Lalonde, S.V., Ireland, T.R., Thomazo, C., van Kranendonk, M.J., Busigny, V., 2018. Globally asynchronous sulphur isotope signals require re-definition of the Great Oxidation Event. Nature Communications 9, Article 2245. Great Oxidation Event (GOE) has been defined as the time interval when sufficient atmospheric oxygen accumulated to prevent the generation and preservation of mass-independent fractionation of sulphur isotopes (MIF-S) in sedimentary rocks. Existing correlations suggest that the GOE was rapid and globally synchronous. Here we apply sulphur isotope analysis of diagenetic sulphides combined with U-Pb and Re-Os geochronology to document the sulphur cycle evolution in Western Australia spanning the GOE. Our data indicate that, from ~2.45?Gyr to beyond 2.31?Gyr, MIF-S was preserved in sulphides punctuated by several episodes of MIF-S disappearance. These results establish the MIF-S record as asynchronous between South Africa, North America and Australia, argue for regional-scale modulation of MIF-S memory effects due to oxidative weathering after the onset of the GOE, and suggest that the current paradigm of placing the GOE at 2.33–2.32?Ga based on the last occurrence of MIF-S in South Africa should be re-evaluated.Phillips, S.C., Hong, W.-L., Johnson, J.E., Fahnestock, M.F., Bryce, J.G., 2018. Authigenic carbonate formation influenced by freshwater inputs and methanogenesis in coal-bearing strata offshore Shimokita, Japan (IODP site C0020). Marine and Petroleum Geology 96, 288-303. carbonate chemistry and mineralogy provide key insights into diagenetic pathways and microbial processes in sedimentary records. We characterize the mineralogy, elemental composition, and isotopic composition of 28 authigenic carbonate nodules recovered from coal-bearing forearc sediments offshore Shimokita Peninsula (Japan) to better understand fluid sources, diagenetic environments, and biogeochemical processes associated with subsiding sediments containing high organic carbon content. The carbonate nodules were collected at Integrated Ocean Drilling Program (IODP) Site C0020 from sediment cores between 1604 and 2460?m below seafloor (mbsf) spanning a transition from terrestrial to marine depositional environments. These carbonates range from <1?cm to 9?cm thick and most commonly occur in sandstones/sands adjacent to the 2?km-deep early Miocene to late Oligocene lignite beds deposited within terrestrial to estuarine sediments. Almost all samples are composed of relatively pure siderite (74–92% FeCO3) with two interlayered siderite and low Mg-calcite samples below 2400?mbsf. High δ13C (?1.2 to +12.8‰ VPDB) signatures indicate the carbonates were precipitated within the zone of methanogenesis, which was likely coupled to the weathering of silicate minerals, with no evidence of any carbonate produced as a result of anaerobic oxidation of methane. Low δ18O values (?7.4 to ?1.6‰ VPDB) suggest the influence of meteoric waters during carbonate precipitation. High 87Sr/86Sr values in the carbonates within the main coal-bearing unit relative to the values in pore water suggest mineral precipitation began more shallowly than their current depth and was influenced by meteoric water and/or volcanic material weathering endmembers. Low rare earth element (REE) content and enrichment in heavier REEs suggest carbonate precipitation occurred mainly during early burial. Iron availability for siderite precipitation was likely influenced by microbial reduction of Fe (oxyhydr)oxides. The precipitation of these carbonates likely began within shallow freshwater/brackish aquifers and continued with burial, based on their composition and host strata.Pietrucci, F., Aponte, J.C., Starr, R., Pérez-Villa, A., Elsila, J.E., Dworkin, J.P., Saitta, A.M., 2018. Hydrothermal decomposition of amino acids and origins of prebiotic meteoritic organic compounds. ACS Earth and Space Chemistry 2, 588-598. organic compounds found in carbonaceous chondrite meteorites provide insight into primordial solar system chemistry. Evaluating the formation and decomposition mechanisms of meteoritic amino acids may aid our understanding of the origins of life and homochirality on Earth. The amino acid glycine is widespread in meteorites and other extraterrestrial environments; other amino acids, such as isovaline, are found with enantiomeric excesses in some meteorites. The relationship between meteoritic amino acids and other compounds with similar molecular structures, such as aliphatic monoamines and monocarboxylic acids is unclear; experimental results evaluating the decomposition of amino acids have produced inconclusive results about the preferred pathways, reaction intermediates, and if the conditions applied may be compatible with those occurring inside meteoritic parent bodies. In this work, we performed extensive tandem metadynamics, umbrella sampling, and committor analysis to simulate the neutral mild hydrothermal decomposition mechanisms of glycine and isovaline and put them into context for the origins of meteoritic organic compounds. Our ab initio simulations aimed to determine free energy profiles and decomposition pathways for glycine and isovaline. We found that under our modeled conditions, methylammonium, glycolic acid, and sec-butylamine are the most likely decomposition products. These results suggest that meteoritic aliphatic monocarboxylic acids are not produced from decomposition of meteoritic amino acids. Our results also indicate that the decomposition of l-isovaline prefers an enantioselective pathway resulting in the production of (S)-sec-butylamine.Pinnock, T., Voordouw, J., Voordouw, G., 2018. Use of carbon steel ball bearings to determine the effect of biocides and corrosion inhibitors on microbiologically influenced corrosion under flow conditions. Applied Microbiology and Biotechnology 102, 5741-5751. consortium of sulfate-reducing bacteria consisting mostly of Desulfovibrio, Desulfomicrobium, and Desulfocurvus from oil field produced water was cultivated in a chemostat, receiving medium with 20?mM formate and 10?mM sulfate as the energy and 1?mM acetate as the carbon source. The chemostat effluent, containing 5?mM sulfide and 0.5?mM of residual acetate, was passed through 1-ml syringe columns with 60 carbon steel ball bearings (BBs) of 53.6?±?0.1?mg each at a flow rate of 0.8?ml/h per column. These were treated every 5?days with 1.6?ml of 300?ppm of glutaraldehyde (Glut), tetrakis(hydroxymethyl)phosphonium sulfate (THPS), benzalkonium chloride (BAC), or Glut/BAC, a mixture of Glut and BAC. Alternatively, BBs were treated with 33% (v/v) of a water-soluble (CR_W) or an oil-soluble (CR_O1 or CR_O3) corrosion inhibitor for 20?s after which the corrosion inhibitor was drained off and BBs were packed into columns. The effluent of untreated control columns had no acetate. Treatment with the chemically reactive biocides Glut and THPS, as well as with Glut/BAC, gave a transient increase of acetate indicating decreased microbial activity. This was not seen with BAC alone indicating it to be the least effective biocide. Relative to untreated BBs (100%), those treated periodically with Glut, THPS, BAC, or Glut/BAC had a general weight loss corrosion rate of 91, 81, 45, and 36% of the untreated rate of 0.104?±?0.004?mm/year, respectively. Single treatment with corrosion inhibitors decreased corrosion to 48, 2, and 1% of the untreated rate for CR_W, CR_O1 and CR_O3, respectively. Analysis of the distribution of corrosion rates from the weight loss of individual BBs (N?=?120) indicated the presence of a more slowly and a more rapidly corroding group. BAC treatment prevented emergence of the latter, and this quaternary ammonium detergent appeared most effective in decreasing corrosion not because of its biocidal properties, but because of its corrosion inhibitory properties.Pizzarello, S., Yarnes, C.T., 2018. Chiral molecules in space and their possible passage to planetary bodies recorded by meteorites. Earth and Planetary Science Letters 496, 198-205. searched the ethanol extracts of the Murchison meteorite for propylene oxide (PrOx), the only chiral molecule discovered so far outside solar environments, and detected its likely derivative after isolation of the low boiling components of the extract. This compound is also chiral and, upon hydrolysis, produces propylene glycol (PrGl), the expected product of PrOx under these conditions. Both the PrOx derivative and PrGl were detected with variable enantiomeric excesses (ee) averaging at ～10% and to have the (R)(+) configuration, i.e., for the same optical isomer as for sugars in the biosphere and sugar derivatives in meteorites. Besides PrGl, the hydrolysates also contained homologous compounds and polymeric materials with the combined δD (‰) of +235 and +65, respectively, suggesting a yet unknown compositional complexity in meteorites. The occurrence of ee in interstellar PrOx cannot be ascertained with current spectroscopic methodologies, however, the overall data reported here would allow to imply it.Podgorski, D.C., Zito, P., McGuire, J.T., Martinovic-Weigelt, D., Cozzarelli, I.M., Bekins, B.A., Spencer, R.G.M., 2018. Examining natural attenuation and acute toxicity of petroleum-derived dissolved organic matter with optical spectroscopy. Environmental Science & Technology 52, 6157-6166. samples containing petroleum-derived dissolved organic matter (DOMHC) originating from the north oil body within the National Crude Oil Spill Fate and Natural Attenuation Research Site near Bemidji, MN, USA were analyzed by optical spectroscopic techniques (i.e., absorbance and fluorescence) to assess relationships that can be used to examine natural attenuation and toxicity of DOMHC in contaminated groundwater. A strong correlation between the concentration of dissolved organic carbon (DOC) and absorbance at 254 nm (a254) along a transect of the DOMHC plume indicates that a254 can be used to quantitatively assess natural attenuation of DOMHC. Fluorescence components, identified by parallel factor (PARAFAC) analysis, show that the composition of the DOMHC beneath and adjacent to the oil body is dominated by aliphatic, low O/C compounds (“protein-like” fluorescence) and that the composition gradually evolves to aromatic, high O/C compounds (“humic-/fulvic-like” fluorescence) as a function of distance downgradient from the oil body. Finally, a direct, positive correlation between optical properties and Microtox acute toxicity assays demonstrates the utility of these combined techniques in assessing the spatial and temporal natural attenuation and toxicity of the DOMHC in petroleum-impacted groundwater systems.Pogány, ?., Torda, O., Marinelli, L., Lenkei, R., Junó, V., Pongrácz, P., 2018. The behaviour of overweight dogs shows similarity with personality traits of overweight humans. Royal Society Open Science 5, Article 172398. food intake and the resulting excess weight gain is a growing problem in human and canine populations. Dogs, due to their shared living environment with humans, may provide a beneficial model to study the causes and consequences of obesity. Here, we make use of two well-established research paradigms (two-way choice paradigm and cognitive bias test), previously applied with dogs, to investigate the role of obesity and obesity-prone breeds for food responsiveness. We found no evidence of breed differences in food responsiveness due to one breed being more prone to obesity than another. Breed differences found in this study, however, can be explained by working dog status, i.e. whether the dog works in cooperation with, or independently from, humans. Our results also confirm that overweight dogs, as opposed to normal weight dogs, tried to maximize food intake from the higher quality food and hesitated to do the task when the food reward was uncertain. These results are very similar to those expected from the parallel models that exist between certain personality traits and being overweight in humans, suggesting that dogs are indeed a promising model for experimentally investigating obesity in humans.Pollo, B.J., Alexandrino, G.L., Augusto, F., Hantao, L.W., 2018. The impact of comprehensive two-dimensional gas chromatography on oil & gas analysis: Recent advances and applications in petroleum industry. TrAC Trends in Analytical Chemistry 105, 202-217. two-dimensional gas chromatography (GC?×?GC) has impacted the workflow of GC-based methods used in petroleum industry. Application of GC?×?GC to petroleomic investigations have guided sample preparation to faster, cleaner, and more reliable formats. For instance, solvent consumption has been drastically reduced when using miniaturized devices in routine applications. Furthermore, flow-modulation has enabled cost-effective analysis and powerful separations of gases, fuels, and crude oils. Hyphenation of GC?×?GC to conventional and high resolution mass spectrometry has enabled the detection and identification of hundreds of compounds in a single analysis. Pixel-based methods enabled efficient handling of big data generated by GC?×?GC in forensic and geochemical investigations. This review has highlighted an ever-growing demand for modern and powerful analytical methods for oil & gas industry. Here, we described the most recent advances to sample preparation, GC?×?GC instrumentation, and multivariate data analysis in petroleum industry, including microextractions, high temperature GC?×?GC, and pixel-based data analysis.Ponsaing, L., Bojesen-Koefoed, J.A., Thomsen, E., Stemmerik, L., 2018. Temporal organic facies variations of Upper Jurassic - lowermost Cretaceous source rocks in the Danish Central Graben, North Sea. International Journal of Coal Geology 195, 217-237. Upper Jurassic – lowermost Cretaceous marine mudstones of the Farsund Formation constitute the principal source rocks in the Danish North Sea sector with the uppermost Bo Member considered most prolific. However, the areal distribution of the Bo Member is limited and since it is thermally immature over large areas it is unlikely that this interval has generated sufficient quantities of petroleum to fill the reservoirs in the Danish sector. In search for additional source rocks potential we have investigated the lower part of the Farsund Formation using a sequence stratigraphic framework. Organic geochemical screening and petrographic analyses of core and cuttings samples have been performed to define the source potential and map the regional distribution of organic-rich sequences in the Upper Jurassic succession. The study outlines variations of both maturity, source rock quality, and kerogen quality at sequence level with an upward improvement from poor gas-prone Type II kerogen in the Kimm-1 and Kimm-3 sequences to highly oil-prone Type II kerogen in the Volg-1, Volg-4 and Ryaz-1 sequences. The kerogen is dominated by fluorescent AOM and liptinite and structural alginite in form of Leiosphaerida- and Tasmanites-type telalginites throughout the entire succession, with vertical- and regional variations in the amount of larger Tasmanites. The study shows that the shales in Volg-1 and -3 sequences are organic-rich and oil prone with TOC?&gt;?4?wt% and HI?&gt;?340?mg HC/g TOC. Particularly the Volg-1 sequence, being the thickest and laterally most widespread forms a significant supplementary source for oil in the Danish sector.Poole, C.F., 2018. Chromatographic test methods for characterizing alkylsiloxane-bonded silica columns for reversed-phase liquid chromatography. Journal of Chromatography B 1092, 207-219. obstacles to formulating a simple retention mechanism for reversed-phase liquid chromatography have a direct impact on the development of experimental methods for column characterization as they limit our capability to understand observed differences in retention at a system level. These problems arise from the heterogeneous composition of the stationary phase, the difficulty of providing a working definition for the phase ratio, and uncertainty as to whether the distribution mechanism for varied compounds is a partition, adsorption or mixed (combination) of these models. Retention factor and separation factor measurements offer little guidance as they represent an average of various and variable contributing factors that can only be interpreted by assuming a specific model. Column characterization methods have tended to ignore these difficulties by inventing a series of terms to describe column properties, such as hydrophobicity, hydrophilicity, silanol activity, steric resistance, etc., without proper definition. This has allowed multiple scales to be proposed for the same property which generally are only weakly correlated. Against this background we review the major approaches for the characterization of alkylsiloxane-bonded silica stationary phases employing prototypical compounds, the hydrophobic-subtraction model and the solvation parameter model. Those methods using prototypical compounds are limited by the lack of compounds with a singular dominant interaction. The multivariate approaches that extract column characteristic properties from the retention of varied compounds are more hopeful but it is important to be more precise in defining the characteristic column properties and cognizant that general interpretation of these properties for varied columns cannot escape the problem of a poor understanding of the distribution mechanism.Postberg, F., Khawaja, N., Abel, B., Choblet, G., Glein, C.R., Gudipati, M.S., Henderson, B.L., Hsu, H.-W., Kempf, S., Klenner, F., Moragas-Klostermeyer, G., Magee, B., N?lle, L., Perry, M., Reviol, R., Schmidt, J., Srama, R., Stolz, F., Tobie, G., Trieloff, M., Waite, J.H., 2018. Macromolecular organic compounds from the depths of Enceladus. Nature 558, 564-568.’s moon Enceladus harbours a global water ocean , which lies under an ice crust and above a rocky core . Through warm cracks in the crust a cryo-volcanic plume ejects ice grains and vapour into space that contain materials originating from the ocean. Hydrothermal activity is suspected to occur deep inside the porous core, powered by tidal dissipation . So far, only simple organic compounds with molecular masses mostly below 50 atomic mass units have been observed in plume material. Here we report observations of emitted ice grains containing concentrated and complex macromolecular organic material with molecular masses above 200 atomic mass units. The data constrain the macromolecular structure of organics detected in the ice grains and suggest the presence of a thin organic-rich film on top of the oceanic water table, where organic nucleation cores generated by the bursting of bubbles allow the probing of Enceladus’ organic inventory in enhanced concentrations.Powers, L.C., Luek, J.L., Schmitt-Kopplin, P., Campbell, B.J., Magen, C., Cooper, L.W., Gonsior, M., 2018. Seasonal changes in dissolved organic matter composition in Delaware Bay, USA in March and August 2014. Organic Geochemistry 122, 87-97. combined Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and mass spectrometric analysis of stable carbon isotopes, a traditional method for tracking DOM sources, to investigate the variation in the complexity of water samples collected along a salinity gradient in Delaware Bay in March and August 2014. Detailed analyses of optical properties (ultraviolet and visible (UV-Vis) absorbance and excitation-emission matrix (EEM) fluorescence spectroscopy) were carried out. Results from statistical parallel factor analysis (PARAFAC) of EEM data were also used to track and further constrain fluorescent DOM (FDOM). Optical analyses and FT-ICR-MS data showed large differences between late winter and summer conditions, and the stable carbon isotopic composition was more variable in summer than in late winter. Although terrestrial inputs of DOM are evident at low salinities in both seasons, our data suggest that a significant source of FDOM, from either in situ water column production or from benthic aquatic or semi-aquatic plant communities, contributes DOM to low and mid-salinity waters in Delaware Bay during summer but not in late winter.Prajapat, G., Rellegadla, S., Jain, S., Agrawal, A., 2018. Reservoir souring control using benzalkonium chloride and nitrate in bioreactors simulating oil fields of western India. International Biodeterioration & Biodegradation 132, 30-39. located in western India produce crude by injection of large amounts of water during secondary oil recovery. This water is obtained from underground aquifer and contains 5?mM sulfate approximately. Sulfate present in this water is converted in to sulfide by sulfate reducing bacteria (SRB) present in the reservoir. Increased concentration of sulfide in the production fluid negatively impacts oil production and is known as reservoir souring. Most probable number and quantitative PCR enumerated 103-108 SRB ml?1 in various field installations. Isolates from produced water in sulfate containing medium showed similarity with Desulfotomaculum, Desulfomicrobium and Thermodesulfobacterium genera. Similarly, isolates from produced water in nitrate containing medium were related to Tepidiphilus, Paenibacillaceae, Kocuria and Thauera genera. In the present study four sand packed bioreactors simulating moderately high temperature oil reservoir were used for different souring control treatments. Results revealed that continuous injection of 4?mM nitrate or 1.5?mM benzalkonium chloride (BAC) was not able to control souring. However, co-injection of 2?mM nitrate and 0.75?mM BAC completely ceased sulfide production and controlled souring.Prakoso, A., Punase, A., Rogel, E., Ovalles, C., Hascakir, B., 2018. Effect of asphaltene characteristics on its solubility and overall stability. Energy & Fuels 32, 6482-6487. molecular structure, high impurity content, and self-association tendency of asphaltenes make the determination of their phase behavior very difficult. Because asphaltene phase behavior is indicative of asphaltene stability within the bulk oil, it is very important to understand its stability. Various production and flow assurance challenges related to precipitation of unstable asphaltenes can be prevented by proper comprehension of asphaltene stability. This study provides a data set on 11 different asphaltenes, which helps us to understand the complicated nature of the components of asphaltenes and crude oils that play an important role in maintaining the stability of asphaltenes. In addition to the physical and chemical characterizations, elemental analysis and ΔPS parameter, which is the indication of the solubility of asphaltenes in different solvents of the bulk oil samples, were measured and evaluated. The results of this study show that the presence of paraffinic wax and water within the crude oil samples along with impurities in the form of reservoir fines can greatly affect the stability of asphaltenes. The organometallic content of crude oil destabilizes asphaltenes, whereas a high fine content increases the stability of asphaltenes.Pratt, C., Tate, K., 2018. Mitigating methane: Emerging technologies to combat climate change’s second leading contributor. Environmental Science & Technology 52, 6084-6097. (CH4) is the second greatest contributor to anthropogenic climate change. Emissions have tripled since preindustrial times and continue to rise rapidly, given the fact that the key sources of food production, energy generation and waste management, are inexorably tied to population growth. Until recently, the pursuit of CH4 mitigation approaches has tended to align with opportunities for easy energy recovery through gas capture and flaring. Consequently, effective abatement has been largely restricted to confined high-concentration sources such as landfills and anaerobic digesters, which do not represent a major share of CH4’s emission profile. However, in more recent years we have witnessed a quantum leap in the sophistication, diversity and affordability of CH4 mitigation technologies on the back of rapid advances in molecular analytical techniques, developments in material sciences and increasingly efficient engineering processes. Here, we present some of the latest concepts, designs and applications in CH4 mitigation, identifying a number of abatement synergies across multiple industries and sectors. We also propose novel ways to manipulate cutting-edge technology approaches for even more effective mitigation potential. The goal of this review is to stimulate the ongoing quest for and uptake of practicable CH4 mitigation options; supplementing established and proven approaches with immature yet potentially high-impact technologies. There has arguably never been, and if we do not act soon nor will there be, a better opportunity to combat climate change’s second most significant greenhouse gas.Prieto-Barajas, C.M., Alcaraz, L.D., Valencia-Cantero, E., Santoyo, G., 2018. Life in hot spring microbial mats located in the Trans-Mexican Volcanic Belt: A 16S/18S rRNA gene and metagenomic analysis. Geomicrobiology Journal 35, 704-712. geothermal system of the Araró region, located in the Trans-Mexican Volcanic Belt of México, hosts various hot springs with unique physicochemical characteristics, including temperatures ranging from 45°C to 78°C. The microbial diversity in these hot springs has been explored only by culture-dependent surveys. In this study, we performed metagenomic Illumina MiSeq, and 16S and 18S rRNA pyrosequencing analysis of the microbial life are residing in the microbial mats of the springs called “Tina–Bonita”. Our results show the presence of 186 operational taxonomic units, 99.7% of which belong to bacteria, 0.27% to eukaryotes, and 0.03% to archaea. The most abundant bacterial divisions are the Proteobacteria, Chloroflexi, and Cyanobacteria, which include 105 genera. The ecological indexes indicate that the microbial mats have moderate microbial diversity. An abundant group of genes that participate in photosynthesis, including photosynthetic electron transport, as well as photosystems I and II, were detected. Another cluster of genes was found that participates in sulfur, nitrogen, and methane metabolism. Finally, this phylogenetic and metagenomic analysis revealed an unexpected taxonomic and genetic diversity, expanding our knowledge of microbial life under specific extreme conditions.Primaz, C.T., Schena, T., Lazzari, E., Caram?o, E.B., Jacques, R.A., 2018. Influence of the temperature in the yield and composition of the bio-oil from the pyrolysis of spent coffee grounds: Characterization by comprehensive two dimensional gas chromatography. Fuel 232, 572-580. is an important agricultural product being one of the most consumed beverages in the world. The goal of this work is to apply the pyrolysis to this residue for the production of bio-oil. The pyrolysis of the biomass (SCG) was done in a fixed bed reactor and varying the final temperature (400, 450, 500, 550 and 600?°C). The higher crude bio-oil yield was obtained at 500?°C with a flow of N2 in 100?mL/min (mass yield?=?30.51%). The bio-oil produced by pyrolysis of SCG had its chemical composition analyzed by comprehensive two-dimensional gas chromatography coupled to mass spectrometry detector (GC?×?GC/TOF-MS) and associated with LTPRI. This bio-oil showed potential for the production of chemical and liquid fuels, evidencing to be a good option for the destination of this waste. Its composition showed high amount of phenols, fatty acids and nitrogen compounds. The major compounds in the bio-oil sample were n-hexadecanoic acid (palmitic acid) (19%), 9-octadecenoic acid (oleic acid) (11%), octadecanoic acid (stearic acid) (10%).Pupp, M., Bechtel, A., ?ori?, S., Gratzer, R., Rustamov, J., Sachsenhofer, R.F., 2018. Eocene and Oligo‐Miocene source rocks in the Rioni and Kura basins of Georgia: Depositional environment and petroleum potential. Journal of Petroleum Geology 41, 367-392. over a century, oil has been produced in Georgia from oilfields located in the foreland basins between the Greater and Lesser Caucasus foldbelts. To date, little information on the associated source rocks has been available. In this context, this paper presents a study of 380 samples of Eocene (Kuma Formation) and Oligocene to Lower Miocene (Maikop Group) source rocks from three outcrop sections in the Rioni and Kura Basins. The Kuma Formation in the Rioni Basin is composed of fully‐marine marls and is about 40 m thick. At the Martivili and Khobi sections, the formation is thermally immature and has an average TOC of 3.2 wt%. The hydrogen indices (HI) of 300–600 mg HC/g TOC indicate that the organic matter is oil‐prone Type II kerogen. The oil generation potential is between 1.0 and 2.4 t HC/m2, and the Kuma Formation is therefore interpreted as a prolific source rock. The Maikop Group in the Rioni Basin was studied at the Martvili section, where it is thermally immature. The Oligocene succession is divided by calcareous shales deposited during the Solenovian Event (at the onset of nannoplankton zone NP23) into Pshekhian and Solenovian‐to‐Kalmykian intervals. The Pshekhian interval (NP21‐22) is over 60 m thick and comprises a marly lower part and a shale‐rich upper part, and contains high quantities (average 2.7 wt% TOC) of Type II‐III kerogen (average HI: 278 mg HC/g TOC). The overlying largely carbonate‐free shale succession, 424 m thick, is less organic matter ‐rich (～2.0 %TOC) and contains dominantly Type III kerogen (average HI: 140 mg HC/g TOC). In total, the Maikop Group has a generation potential of about 4 t HC/m2, a value which is higher than in most other sub‐basins in the Eastern Paratethys. Because the Rioni Basin continues westwards into the Black Sea, these results are relevant for future exploration in the eastern part of the Black Sea Basin. The Maikop Group in the western Kura Basin in the Tbilisi area is over 3500 m thick and includes numerous sandstone beds. Because of the great thickness of the Maikop Group and the presence of about 3 km of overburden, which was removed during Miocene to Recent unroofing, potential source rocks in the Eocene to Lower Oligocene succession have reached oil window maturities but their hydrocarbon potential is low. Purcaro, G., Stefanuto, P.-H., Franchina, F.A., Beccaria, M., Wieland-Alter, W.F., Wright, P.F., Hill, J.E., 2018. SPME-GC×GC-TOF MS fingerprint of virally-infected cell culture: Sample preparation optimization and data processing evaluation. Analytica Chimica Acta 1027, 158-167. metabolomics study of volatile organic compounds produced by different cell cultures is a field that has gained increasing attention over the years. Solid-phase microextraction has been the sampling technique of choice for most of the applications mainly due to its simplicity to implement. However, a careful optimization of the analytical conditions is necessary to obtain the best performances, which are highly matrix-dependent. In this work, five different solid-phase microextraction fibers were compared for the analysis of the volatiles produced by cell culture infected with the human respiratory syncytial virus. A central composite design was applied to determine the best time-temperature combination to maximize the extraction efficiency and the salting-out effect was evaluated as well. The linearity of the optimized method, along with limits of detection and quantification and repeatability was assessed. Finally, the effect of i) different normalization techniques (i.e. z-score and probabilistic quotient normalization), ii) data transformation (i.e. in logarithmic scale), and iii) different feature selection algorithms (i.e. Fisher ratio and random forest) on the capability of discriminating between infected and not-infected cell culture was evaluated.Pursch, M., Wegener, A., Buckenmaier, S., 2018. Evaluation of active solvent modulation to enhance two-dimensional liquid chromatography for target analysis in polymeric matrices. Journal of Chromatography A 1562, 78-86. new methodology is presented for two-dimensional liquid chromatography (2D-LC) separations of polymers. Active solvent modulation (ASM) was evaluated in its effectiveness to enhance solvent compatibility for both separation dimensions. As an example the determination of target compounds in epoxy resins was used. Ultra-high pressure size-exclusion chromatography was applied in the first dimension using THF as the solvent. The second dimension separation was operated in reversed-phase mode using an acetonitrile/water gradient. ASM prevents sample breakthrough in the second dimension and produces chromatograms that are of great peak shape and high resolution. It enables very sensitive determination of target components down to the low ppm level. The resulting high-speed 2D-LC method (10?min analysis time) showed good linearity (R2?>?0.9995) and reproducibility (as low as 0.3–0.7% peak area RSD). ASM was also applied in comprehensive 2D-LC (SECxLC) mode for characterization of molecular weight and chemical composition distribution of a polymer blend consisting of epoxy novolac and phenol novolac. The SECxLC separation was executed at short run times (20?min). ASM technology can markedly enhance productivity in 2D-LC analysis for many complex sample matrices.Qiao, Y., Chen, D., Wen, D., 2018. Use of coupled wavelength ultraviolet light-emitting diodes for inactivation of bacteria in subsea oil-field injection water. Science of The Total Environment 640-641, 757-763. development of subsea injection water disinfection systems will enable the novel exploration of offshore oilfields. Ultraviolet light emitting diodes (UV-LEDs) with peak wavelengths at 255?nm, 280?nm, 350?nm, and combinations of 255?nm and 350?nm, and 280?nm and 350?nm were investigated in this study to determine their efficiency at disinfecting saprophytic bacteria, iron bacteria, and sulfate reducing bacteria. Results show that UV-LEDs with peak wavelengths at 280?nm were the most practical in this domain because of their high performance in both energy-efficiency and reactivation suppression, although 255?nm UV-LEDs achieved an optimal germicidal effect in dose-based experiments. The use of combined 280?nm and 350?nm wavelengths also induced synergistic bactericidal effects on saprophytic bacteria.Quigley, M.Y., Negassa, W.C., Guber, A.K., Rivers, M.L., Kravchenko, A.N., 2018. Influence of pore characteristics on the fate and distribution of newly added carbon. Frontiers in Environmental Science 6, 51. doi: 10.3389/fenvs.2018.00051. create a transportation network within a soil matrix, which controls the flow of air, water, and movement of microorganisms .The flow of air, water, and movement of microbes, in turn, control soil carbon dynamics. Computed microtomography (μCT) allows for the visualization of pore structure at micron scale, but quantitative information on contribution of pores to fate and protection of soil carbon, essential for modeling, is still lacking. This study uses the natural difference between carbon isotopes of C3 and C4 plants to determine how the presence of pores of different sizes affects spatial distribution patterns of newly added carbon immediately after plant termination and then after one-month incubation. We considered two contrasting soil structure scenarios: soil with the structure kept intact and soil for which the structure was destroyed via sieving. For the experiment, soil was collected from 0-15 cm depth from a 20-year continuous maize (Zea mays L., C4 plant) experiment into which cereal rye (Secale cereale L., C3 plant) was planted. Intact soil fragments (5-6 mm) were procured after 3 months rye growth in a greenhouse. Pore characteristics of the fragments were determined through μCT imaging. Each fragment was sectioned and total carbon, total nitrogen, δ13C, and δ15N were measured. The results indicate that, prior to incubation, greater presence of 40-90 μm pores was associated with higher levels of C3 carbon, pointing to the positive role of these pores in transport of new C inputs. Nevertheless, after incubation, the association became negative, indicating greater losses of newly added C in such pores. These trends were statistically significant in destroyed-structure soil and numerical in intact-structure soil. In soils of intact-structures, after incubation, higher levels of total carbon were associated with greater abundance of 6.5-15 and 15-40 μm pores, indicating a lower carbon loss associated with these pores. The results indicate that, in the studied soil, pores of 40-90 μm size range are associated with the fast influx of new C followed by its quick decomposition, while pores <40 μm tend to be associated with C protection.Racki, G., Rakociński, M., Marynowski, L., Wignall, P.B., 2018. Mercury enrichments and the Frasnian-Famennian biotic crisis: A volcanic trigger proved? Geology 46, 543-546. Frasnian-Famennian (F-F) global event, one of the five largest biotic crises of the Phanerozoic, has been inconclusively linked to rapid climatic perturbations promoted in turn by volcanic cataclysm, especially in the Viluy large igneous province (LIP) of Siberia. Conversely, the triggers of four other Phanerozoic mass extinction intervals have decisively been linked to LIPs, owing to documented mercury anomalies, shown as the diagnostic proxy. Here, we report multiple Hg enrichments in the two-step late Frasnian (Kellwasser) crisis interval from paleogeographically distant successions in Morocco, Germany, and northern Russia. The distinguishing signal, >1 ppm Hg in the domain of closing Rheic Ocean, was identified in different lithologies immediately below the F-F boundary and approximately correlated with the onset of the main extinction pulse. This key Hg anomaly, comparable only with an extreme spike known from the end-Ordovician extinction, was not controlled by increased bioproductivity in an anoxic setting. We suggest, therefore, that the global chemostratigraphic pattern near the F-F boundary records a greatly increased worldwide Hg input, controlled by the Center Hill eruptive pulse of the Eovariscan volcanic acme, but likely not manifested exclusively by LIP(s). Consequently, all five major biotic crises of the Phanerozoic have now been more reliably linked to volcanic cataclysms.Rakhmatullin, I.Z., Efimov, S.V., Tyurin, V.A., Al-Muntaser, A.A., Klimovitskii, A.E., Varfolomeev, M.A., Klochkov, V.V., 2018. Application of high resolution NMR (1H and 13C) and FTIR spectroscopy for characterization of light and heavy crude oils. Journal of Petroleum Science and Engineering 168, 256-262. nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy experiments were applied to obtain detailed information on the hydrocarbon chemistry of three light and three heavy crude oils. Quantitative fractions of aromatic molecules and functional groups constituting oil hydrocarbons were determined by 13C NMR spectroscopy and comparative analysis of the oil samples with different viscosity, origin and preliminary treatment. SARA composition and some important information about aromaticity, oxidation behavior, branching, aliphaticity and sulfurization of studied oil samples were obtained. Integral characteristics of high-resolution NMR and FTIR spectra have a great potential to study the structure and characterization of light and heavy crude oils, which could substitute present traditional fractionation procedures. Relationships between spectroscopic parameters obtained by high-resolution NMR and FTIR spectroscopy methods and crude oil compositions can be useful for fast prediction of crude oil properties due to different type of treatment, including thermal methods for enhanced oil recovery. Also quantitative proportions of functional groups obtained by NMR and spectral indices obtained by FTIR can be one of the criteria for developing fingerprint approach.Ramos, R., Pajares, S., 2018. Reviews and syntheses: Processes and functional genes involved in nitrogen cycling in marine environments. Biogeosciences Discussions 2018, 1-50. is a key element for life in the oceans. It controls primary productivity in many parts of the global ocean, consequently playing a crucial role in the uptake of atmospheric carbon dioxide. The nitrogen cycle is driven by complex biogeochemical transformations mediated by microorganisms, including classical processes such as nitrogen fixation, assimilation, nitrification, denitrification, and dissimilarity nitrate reduction to ammonia, as well as novel processes such as anaerobic ammonium oxidation, comammox and nitrite-driven anaerobic methane oxidation. The nitrogen cycle maintains the functioning of marine ecosystems and will be a crucial component in how the ocean responds to global environmental change. In this review, we summarize the current understanding of the marine microbial nitrogen cycle, its underlying biochemical and enzymatic reactions, the ecology and distribution of the microorganisms involved, and the main impacts of anthropogenic activities.Rampler, E., Criscuolo, A., Zeller, M., El Abiead, Y., Schoeny, H., Hermann, G., Sokol, E., Cook, K., Peake, D.A., Delanghe, B., Koellensperger, G., 2018. A novel lipidomics workflow for improved human plasma identification and quantification using RPLC-MSn methods and isotope dilution strategies. Analytical Chemistry 90, 6494-6501. identification and quantification are essential objectives in comprehensive lipidomics studies challenged by the high number of lipids, their chemical diversity, and their dynamic range. In this work, we developed a tailored method for profiling and quantification combining (1) isotope dilution, (2) enhanced isomer separation by C30 fused-core reversed-phase material, and (3) parallel Orbitrap and ion trap detection by the Orbitrap Fusion Lumos Tribid mass spectrometer. The combination of parallelizable ion analysis without time loss together with different fragmentation techniques (HCD/CID) and an inclusion list led to higher quality in lipid identifications exemplified in human plasma and yeast samples. Moreover, we used lipidome isotope-labeling of yeast (LILY)—a fast and efficient in vivo labeling strategy in Pichia pastoris—to produce (nonradioactive) isotopically labeled eukaryotic lipid standards in yeast. We integrated the 13C lipids in the LC-MS workflow to enable relative and absolute compound-specific quantification in yeast and human plasma samples by isotope dilution. Label-free and compound-specific quantification was validated by comparison against a recent international interlaboratory study on human plasma SRM 1950. In this way, we were able to prove that LILY enabled quantification leads to accurate results, even in complex matrices. Excellent analytical figures of merit with enhanced trueness, precision and linearity over 4–5 orders of magnitude were observed applying compound-specific quantification with 13C-labeled lipids. We strongly believe that lipidomics studies will benefit from incorporating isotope dilution and LC-MSn strategies.Ran, L., Tian, M., Fang, N., Wang, S., Lu, X., Yang, X., Cho, F., 2018. Riverine carbon export in the arid to semiarid Wuding River catchment on the Chinese Loess Plateau. Biogeosciences 15, 3857-3871. export of terrestrially derived carbon represents a key component of the global carbon cycle. In this study we quantify the fate of riverine carbon within the Wuding River catchment on the Chinese Loess Plateau. Export of dissolved organic and inorganic carbon (DOC and DIC) exhibited pronounced spatial and temporal variability. While DOC concentration first presented a downward trend along the river course and then increased in the main-stem river, it showed no significant seasonal differences and was not sensitive to flow dynamics. This likely reflects the predominance of groundwater input over the entire year and its highly stable DOC. DIC concentration in the loess subcatchment is significantly higher than that in the sandy subcatchment, due largely to dissolution of carbonates that are abundant in loess. In addition, bulk particulate organic carbon content (POC%) showed strong seasonal variability with low values in the wet season owing to input of deeper soils by gully erosion. The downstream carbon flux was (7.0?±?1.9)??×??1010?g?C?yr?1 and dominated by DIC and POC. Total CO2 emissions from water surface were (3.7?±?0.6)??×??1010?g?C?yr?1. Radiocarbon analysis revealed that the degassed CO2 was 810–1890 years old, indicating the release of old carbon previously stored in soil horizons. Riverine carbon export in the Wuding River catchment has been greatly modified by check dams. Our estimate shows that carbon burial through sediment storage was (7.8?±?4.1)??×??1010?g?C?yr?1, representing 42?% of the total riverine carbon export from terrestrial ecosystems on an annual basis ((18.5?±?4.5)??×??1010?g?C?yr?1). Moreover, the riverine carbon export accounted for 16?% of the catchment's net ecosystem production (NEP). It appears that a significant fraction of terrestrial NEP in this arid to semiarid catchment is laterally transported from the terrestrial biosphere to the drainage network.Rana, B.S., Cho, D.-W., Cho, K., Kim, J.-N., 2018. Total Acid Number (TAN) reduction of high acidic crude oil by catalytic esterification of naphthenic acids in fixed-bed continuous flow reactor. Fuel 231, 271-280. acid crude oils contain large amount of naphthenic acids which cause serious corrosion problem in petroleum industry. Therefore, the removal of naphthenic acids becomes a great concern and challenge for oil refineries. In this study, the naphthenic acids in high TAN crude oils were removed by esterification with low consumption of methanol using a solid acid catalyst consisting of 12-tungstophosphoric acid (TPA) supported on γ-Al2O3 (TPA/γ-Al2O3) in a fixed-bed up-flow reactor. The catalyst was prepared by conventional wet impregnation method, and it possessed 25?wt% TPA with high dispersion, and large pore structure. TPA leaching problem from catalyst support was not observed during the reaction. The effect of various reaction parameters such as temperature and liquid hour space velocity (LHSV), and methanol to the crude oil ratio on TAN reduction were investigated in detail to maximize TAN reduction. The results revealed that the TPA/γ-Al2O3 catalyst effectively removed the naphthenic acids via esterification in high TAN crude oils. The TAN decreased with increase in methanol/oil mass ratio, reaction temperature, but it increased with increase in LHSV. In a long-term experiments (up to 100?h) running at a reaction temperature of 250?°C and LHSV of 3?h?1 using 2?wt% methanol in acidic crude oil, the TANs of acidic crude oil reduced from 2.0?mg KOH/g to a value below 0.5?mg KOH/g which is an acceptable TAN value of crude oil to process in the refineries without material upgrades.Rapf, R.J., Perkins, R.J., Dooley, M.R., Kroll, J.A., Carpenter, B.K., Vaida, V., 2018. Environmental processing of lipids driven by aqueous photochemistry of α-keto acids. ACS Central Science 4, 624-630. can initiate photochemical reactions of organic molecules though direct photolysis, photosensitization, and indirect processes, often leading to complex radical chemistry that can increase molecular complexity in the environment. α-Keto acids act as photoinitiators for organic species that are not themselves photoactive. Here, we demonstrate this capability through the reaction of two α-keto acids, pyruvic acid and 2-oxooctanoic acid, with a series of fatty acids and fatty alcohols. We show for five different cases that a cross-product between the photoinitiated α-keto acid and non-photoactive species is formed during photolysis in aqueous solution. Fatty acids and alcohols are relatively unreactive species, which suggests that α-keto acids are able to act as radical initiators for many atmospherically relevant molecules found in the sea surface microlayer and on atmospheric aerosol particles.Rasmusson, K., Rasmusson, M., Tsang, Y., Benson, S., Hingerl, F., Fagerlund, F., Niemi, A., 2018. Residual trapping of carbon dioxide during geological storage—Insight gained through a pore-network modeling approach. International Journal of Greenhouse Gas Control 74, 62-78. reduce emissions of the greenhouse gas CO2 to the atmosphere, sequestration in deep saline aquifers is a viable strategy. Residual trapping is a key containment process important to the success of CO2 storage operations. While residual trapping affects CO2 migration over large scales, it is inherently a pore-scale process. Pore-network models (PNMs), capturing such processes, are useful for our understanding of residual trapping, and for upscaling trapping parameters for larger scale models. A PNM for simulation of quasi-static two-phase flow; CO2 intrusion (drainage) followed by water flooding (imbibition) was developed. It accounts for pore-scale displacement mechanisms, and was used to investigate residual CO2 trapping. The sensitivity of the residual CO2 saturation to several parameters was studied, to validate a trapping behavior in agreement with earlier studies. Then the PNM was calibrated to core sample data and used to simulate drainage-imbibition scenarios with different turning point saturations. From these the initial-residual saturation curves of CO2 in Heletz sandstone were estimated, essential for future macroscopic-scale simulations. Further, the occurrence of different pore-scale mechanisms were quantified and the size distribution of the residual clusters was shown to exhibit a bimodal appearance. The findings improve the understanding of residual trapping in Heletz sandstone.Reddy, S.B., Pavankumar, P., Sridhar, L., Saha, S., Narahari, S., G., Prabhakar, S., 2018. Differential cationization of fatty acids with monovalent cations studied by electrospray ionization tandem mass spectrometry and a computational approach. Rapid Communications in Mass Spectrometry 32, 1126-1134.: The intercellular and intracellular transport of charged species (Na+/K+) entail interaction of the ions with neutral organic molecules and formation of adduct ions. The rate of transport of the ions across the cell membrane(s) may depend on the stability of the adduct ions, which in turn rely on structural aspects of the organic molecules that interact with the ions. Methods: Positive electrospray ionization (ESI) mass spectra were recorded for the solutions containing fatty acids (FAs) and monovalent cations (X = Li+, Na+, K+, Rb+ and Cs+). Product ion spectra of the [FA + X]+ ions were recorded at different collision energies. Theoretical studies were exploited under both the gas and solvent phase to investigate the structural effects of the FAs during cationization. The stability of [FA + X]+ adduct ions was further estimated by means of AIM topological analyses and interaction energy (IE) values. Results; Positive ion ESI‐MS analyses of the solution of FAs and X+ ions showed preferential binding of the K+ ions to FAs. The K+ ion binding increased with the increase in the number of double bonds in the FAs, while it decreased with the increase in the number of carbon atoms in FAs. Dissociation curves of [FA + X]+ ions indicated the relative stability order of the [FA + X]+ ions and it was in line with the observed trends in ESI‐MS. The solvent phase computational studies divulged the mode of binding and the binding efficiencies of different FAs with monovalent cations. Conclusions: Among the studied monovalent cations, the cationization of FAs follows the order K+> > Na+ > Li+ > Rb+ > Cs+. Docosahexaenoic acid showed high efficiency in binding with the K+ ion. The K+ ion binding efficiency of FAs depends on the number of double bonds in unsaturated FAs and the carbon chain length in saturated FAs. The cationization trends of FAs obtained from the ESI‐MS and ESI‐MS/MS analyses were in good agreement with solvent‐phase computational studies. Redfern, R., Gowland, R., Millard, A., Powell, L., Gr?cke, D., 2018. ‘From the mouths of babes’: A subadult dietary stable isotope perspective on Roman London (Londinium). Journal of Archaeological Science: Reports 19, 1030-1040. (48–410CE) was the focus for Roman administration and trade in Britain; it was established and inhabited by people from across the Empire who continued to practice their diverse food-ways. Roman London was a unique settlement, whose fluctuating economic and political fortunes throughout Roman occupation are clearly evidenced in the archaeological and historical records. This study conducts stable isotope analysis of the diet of a large sample of subadults (0–20years old) dating from the 1st to 4th centuries AD in London. It includes an assessment of breastfeeding and weaning practices, but aims to focus more on the diets of older children and the transition to ‘adult’ dietary behaviours. The rib bones of 100 subadults and 20 adults were sampled for carbon and nitrogen isotopes. Using these data, we identified an infant feeding pattern that differed from contemporaneous sites in Italy and which remained unchanged over time, a special diet for nursing females, and temporal changes in diet, whereby subadults consumed greater quantities of freshwater resources compared to adults during periods of economic instability.Ren, G., Nguyen, Q.P., Lau, H.C., 2018. Laboratory investigation of oil recovery by CO2 foam in a fractured carbonate reservoir using CO2-Soluble surfactants. Journal of Petroleum Science and Engineering 169, 277-296. CO2 flooding has been used as an EOR method for carbonate reservoirs which hold around 60% of the world's oil reserves. However, natural fractures, unfavorable mobility ratio and gravity segregation in carbonate reservoirs often lead to premature CO2 breakthrough and bypassed oil. To remedy this situation, CO2 foam has been used to reduce the mobility of the injected CO2. Typically, this employed a water soluble surfactant for foam propagation. However, surfactant transport in the aqueous phase was often hindered by surfactant adsorption and undesirable chemical reactions with reservoir minerals. In this study, we investigated whether CO2-soluble surfactants were more effective than water-soluble surfactant in oil recovery of fractured carbonate reservoirs under miscible conditions. A series of corefloods were conducted to determine the oil recovery factor (RF), speed of foam propagation and foam strength in artificially fractured carbonate cores at 35?°C (308.15?K) and 1500 psi (1.034*107?Pa) which was above minimum miscibility pressure. Silurian Dolomite outcrop with permeability of 150 md and West Texas Wasson crude were used. The cores were intermediate-wet indicated by both qualitative and quantitative tests. Three different surfactants were compared including an anionic water-soluble surfactant and other two nonionic CO2 soluble surfactants (2-ethyl-1-hexanol with different ethylene oxide groups) with distinct degree of solubility in CO2. Phase behavior experiments indicated these surfactants did not lower the interfacial tension significantly between the crude and water. RF of CO2 flooding was only 24% due to the heterogeneous nature of the fractured core. Co-injection of CO2 and water increased the RF to 35%, which was further increased to 54% when a water-soluble only surfactant presented. However, use of CO2 foam by the two CO2-soluble surfactants increased the RF to 71% and 92% respectively, with a higher RF for the surfactant that partitioned more to the CO2 phase. Also, pressure drop in different sections of the core confirmed that the surfactant which partitioned more into the CO2 phase gave a faster-propagating and stronger foam. These results educated that the partitioning of surfactant into the CO2 phase has several advantages. First, it allows surfactant to be transported in the CO2 phase ahead of the aqueous phase thus leading to faster foam propagation. Second, it generated a stronger foam. The combined effect of the two leaded to higher RF in current scenarios. Several hypotheses based on literature were raised and listed to further interpret the observations. Our results also reinforce that the so-called optimal CO2 soluble surfactant is case dependent and is the function of injection strategy, reservoir environment, and operation pressure or rates as well as other specific conditions. One could tailor a surfactant with suitable solubility in the CO2 phase to optimize oil recovery in fractured carbonates. We believed the results were encouraging enough to warrant further R&D and eventual field piloting.Renne, P.R., Arenillas, I., Arz, J.A., Vajda, V., Gilabert, V., Bermúdez, H.D., 2018. Multi-proxy record of the Chicxulub impact at the Cretaceous-Paleogene boundary from Gorgonilla Island, Colombia. Geology 46, 547-550. 40 m stratigraphic section at Gorgonilla Island, Colombia, provides a unique deep-marine, low-latitude, Southern Hemisphere record of events related to the end-Cretaceous Chicxulub impact and the global Cretaceous/Paleogene boundary (KPB). The KPB is marked by a 20-mm-thick, densely packed spherule bed as defined by planktic foraminifera, in contrast to complex relationships found in high-energy, impact-proximal sites in the Gulf of Mexico and Caribbean basins. The absence of basal Danian foraminiferal Zone P0 may indicate a possible hiatus of <10 ka immediately above the spherule bed, but is most probably an artifact of deposition below the calcite compensation depth as suggested by the nearly complete absence of calcareous fossils for 20 m below the Zone Pα. A weighted mean 40Ar/39Ar age of 66.051 ± 0.031 Ma for 25 fresh glassy spherules unequivocally establishes both their derivation from Chicxulub, and the association between the impact and the KPB. The spherule bed, and Maastrichtian strata below it, display soft-sediment deformation features consistent with strong seismic motion, suggesting that seismic activity in the immediate aftermath of the Chicxulub impact continued for weeks. We discovered a fern-spike immediately above the spherule bed, representing the first record of this pioneer vegetation from the South American continent, and from a low-latitude (tropical) environment.Reolid, J., Betzler, C., 2018. Ichnofabric logs for the characterization of the organic content in carbonates. Marine and Petroleum Geology 95, 246-254. study proposes an approach to visualize ichnological data from cores that allows direct comparison with downhole logs. It provides preliminary but accurate environmental information, especially on the oxygenation and/or the organic matter content at the sea floor. The method comprises three steps: Step 1) ichnological analysis of the sediments including quantification of bioturbation intensity, identification of the main ichnotaxa and sizes of the burrows, depth of burrowing or tiering, and documentation of cross-cutting relationships; Step 2) ichnofabric definition following a series of criteria including the bioturbation index, the ichnoassemblage, and the sediment type; and Step 3) the organization of the ichnofabrics from low bioturbation indices and deep tiers to completely bioturbated. The resulting ichnofabrics are plotted against depth and can directly be compared to spectral natural gamma ray logs, which in the discussed example are dominated by variations of the uranium content reflecting the organic matter content in the sediment. The ichnofabric analysis of carbonate sediment cores of the Maldives, recovered during IODP Expedition 359, demonstrates a good correlation between synthetic ichnofabric logs and downhole gamma radiation logs. The combined study of these logs provides information on the main changes in the organic matter content of the sediment. The graphical representation of ichnofabrics together with gamma ray logs presented here is a very useful implement for sedimentologists working on cores.Reyes-Sosa, M.B., Apodaca-Hernández, J.E., Arena-Ortiz, M.L., 2018. Bioprospecting for microbes with potential hydrocarbon remediation activity on the northwest coast of the Yucatan Peninsula, Mexico, using DNA sequencing. Science of The Total Environment 642, 1060-1074. environments harbor diverse microbial communities, which can contain genera with potential bioremediation activity. Next-generation DNA sequencing was used to identify bacteria to the genus level in water and sediment samples collected from the open ocean, shoreline, wetlands and freshwater upwellings on the northwest coast of the Yucatan Peninsula. Supported by an extensive literature review, a phylogenetic investigation of the communities was done using reconstruction of unobserved states software (PICRUSt) to predict metagenome functional content from the sequenced 16S gene in all the samples. Bacterial genera were identified for their potential hydrocarbon bioremediation activity. These included generalist genera commonly reported in hydrocarbon-polluted areas and petroleum reservoirs, as well as specialists such as Alcanivorax and Cycloclasticus. The highest readings for bacteria with potential hydrocarbon bioremediation activity were for the genera Vibrio, Alteromonas, Pseudomonas, Acinetobacter, Burkholderia, Acidovorax and Pseudoalteromonas from different environments in the study area. Some genera were identified only in specific sites; for example, Aquabacterium and Polaromonas were found only in freshwater upwellings. Variation in genera distribution was probably due to differences in environmental conditions in the sampled zones. Bacterial diversity was high in the study area and included numerous genera with known bioremediation activity. Functional prediction of the metagenome indicated that the studied bacterial communities would most probably degrade toluene, naphthalene, chloroalkane and chloroalkene, with lower degradation proportions for aromatic hydrocarbons, fluorobenzoate and xylene. Differences in predicted degradation existed between sediments and water, and between different locations.Reynolds, L.L., Lajtha, K., Bowden, R.D., Tfaily, M.M., Johnson, B.R., Bridgham, S.D., 2018. The path from litter to soil: Insights into soil C cycling from long‐term input manipulation and high‐resolution mass spectrometry. Journal of Geophysical Research: Biogeosciences 123, 1486-1497. path of carbon (C) from plant litter to soil organic matter (SOM) is key to understanding how soil C stocks and microbial decomposition will respond to climate change and whether soil C sinks can be enhanced. Long?term ecosystem?scale litter manipulations and molecular characterization of SOM provide a unique opportunity to explore these issues. We incubated soils from a 20?year litter input experiment for 525?days and asked how litter quantity and source (i.e., roots versus aboveground litter) affected C cycling, microbial function, and the size and molecular composition of C pools. Input exclusion led to a 30% loss of soil C, attributable largely to the nonmineral?associated C fraction, and to declines in soil C decomposition. The absence of roots caused a shift in the microbial catabolic profile, though there was little evidence that root litter was preferentially stabilized. Although C pool size did not change with litter additions, Fourier transform ion cyclotron resonance mass spectrometry analysis of the finest mineral fraction revealed dramatic changes to the chemical composition of carbon. Lipid content increased proportionally with input addition and was subsequently mineralized during incubation, indicating that this fraction was metabolically active. Moreover, nonmetric dimensional scaling showed that both litter treatments and incubation caused the molecular composition of SOM to change. We conclude that the path of C from litter to soil may involve labile pools and root?driven microbial activity associated directly with SOM in the soil mineral matrix otherwise previously hypothesized to be stable.Rho, W.G., Kim, S.H., Cho, D.-W., Kang, J.W., Lee, C.S., 2018. An experimental and modeling study on incipient hydrate-forming conditions for ternary guests of carbon dioxide, nitrogen and sulfur dioxide. Fluid Phase Equilibria 473, 127-131. carbon dioxide capture and sequestration (CCS) processes, captured CO2 may encounter conditions of hydrate formation due to the presence of water. For stable, long-term operation of CCS processes, hydrate-phase equilibrium data are essential. Captured Hydrates; Sulfur dioxide; Nitrogen; Carbon dioxide; Lattice fluid equation of statefrom combustion of fossil fuel may include other impurities such as N2 and SO2. Phase equilibria including a single impurity (N2 or SO2) have been reported by other researchers, but no experimental observations have been obtained for ternary guest systems. In this work, the incipient hydrate-forming temperatures for a binary guest of CO2 and N2 and a ternary guest of CO2, N2 and SO2 were experimentally measured at 2.0–3.5?MPa. An effect of the ratio between guest components and water was observed. The experimental results were compared with calculations using an equation of state based on a hydrogen-bonding nonrandom lattice fluid (NLF-HB) combined with the van der Waals-Platteeuw model. The model predictions were in good agreement with experimental data with an overall average deviation of 2.6%.Richter, L.V., Mansfeldt, C.B., Kuan, M.M., Cesare, A.E., Menefee, S.T., Richardson, R.E., Ahner, B.A., 2018. Altered microbiome leads to significant phenotypic and transcriptomic differences in a lipid accumulating chlorophyte. Environmental Science & Technology 52, 6854-6863. the challenges facing the economically favorable production of products from microalgae, understanding factors that might impact productivity rates including growth rates and accumulation of desired products, for example, triacylglycerols (TAG) for biodiesel feedstock, remains critical. Although operational parameters such as media composition and reactor design can clearly effect growth rates, the role of microbe–microbe interactions is just beginning to be elucidated. In this study an oleaginous marine algae Chlorella spp. C596 culture is shown to be better described as a microbial community. Perturbations to this microbial community showed a significant impact on phenotypes including sustained differences in growth rate and TAG accumulation of 2.4 and 2.5 fold, respectively. Characterization of the associated community using Illumina 16S rRNA amplicon and random shotgun transcriptomic analyses showed that the fast growth rate correlated with two specific bacterial species (Ruegeria and Rhodobacter spp). The transcriptomic response of the Chlorella species revealed that the slower growing algal consortium C596-S1 upregulated genes associated with photosynthesis and resource scavenging and decreased the expression of genes associated with transcription and translation relative to the initial C596-R1. Our studies advance the appreciation of the effects microbiomes can have on algal growth in bioreactors and suggest that symbiotic interactions are involved in a range of critical processes including nitrogen, carbon cycling, and oxidative stress.Roach, L.A.N., White, D.J., 2018. Evolution of a deep CO2 plume from time-lapse seismic imaging at the Aquistore storage site, Saskatchewan, Canada. International Journal of Greenhouse Gas Control 74, 79-86. Aquistore CO2 Storage Site in southeast Saskatchewan, Canada began CO2 injection in April 2015. CO2 is injected into a 3200?m–deep sandstone reservoir for long-term storage. 3D time-lapse seismic surveys have been acquired using a permanent sparse seismic array to monitor the CO2 plume. Time-lapse data have been acquired prior to CO2 injection (November 2013) and after injection of 36?kilotonnes (February 2016, Monitor 1), and 102?kilotonnes (November 2016, Monitor 2). 3D time-lapse seismic analyses reveal amplitude differences (nRMS of 0.10–0.25) within the reservoir that exceed the background noise-level (nRMS?～?0.03–0.04). These amplitude anomalies are interpreted as zones of CO2 saturation and are thus used to track/map the CO2 plume within the reservoir at these times. They show the development of a stratified CO2 plume that is spreading predominantly along NNW-SSE structural/permeability trends in the reservoir.Rojas, P., Rodríguez, N., de la Fuente, V., Sánchez-Mata, D., Amils, R., Sanz, J.L., 2018. Microbial diversity associated with the anaerobic sediments of a soda lake (Mono Lake, California, USA). Canadian Journal of Microbiology 64, 385-392. lakes are inhabited by important haloalkaliphilic microbial communities that are well adapted to these extreme characteristics. The surface waters of the haloalkaline Mono Lake (California, USA) are alkaline but, in contrast to its bottom waters, do not present high salinity. We have studied the microbiota present in the shoreline sediments of Mono Lake using next-generation sequencing techniques. The statistical indexes showed that Bacteria had a higher richness, diversity, and evenness than Archaea. Seventeen phyla and 8 “candidate divisions” were identified among the Bacteria, with a predominance of the phyla Firmicutes, Proteobacteria, and Bacteroidetes. Among the Proteobacteria, there was a notable presence of Rhodoplanes and a high diversity of sulfate-reducing Deltaproteobacteria, in accordance with the high sulfate-reducing activity detected in soda lakes. Numerous families of bacterial fermenters were identified among the Firmicutes. The Bacteroides were represented by several environmental groups that have not yet been isolated. Since final organic matter in anaerobic environments with high sulfate contents is mineralized mainly by sulfate-reducing bacteria, very little methanogenic archaeal biodiversity was detected. Only 2 genera, Methanocalculus and Methanosarcina, were retrieved. The species similarities described indicate that a significant number of the operational taxonomic units identified may represent new species.Rouhibakhsh, K., Darvish, H., 2018. Utilization of Fuzzy C-means algorithm as a novel predictive tool for estimation of interfacial tension of hydrocarbon and brine. Petroleum Science and Technology 36, 1107-1112. interfacial tension that exists between brine and hydrocarbon is known as one of major properties in petroleum industries because it extremely affects oil trapping in reservoirs and consequently oil recovery. Due to aforementioned reasons the importance of investigation of this parameter has been highlighted. In the present study, Fuzzy C-means (FCM) algorithm was developed to predict interfacial tension between hydrocarbon and brine as function of different parameters such as pressure, temperature, carbon number of hydrocarbon and ionic strength of brine. The obtained results of predicting algorithm expressed its low relative error and deviation from the experimental data which gathered from the literature. Also the coefficients of determination (R2) for training and testing data were calculated 0.9508 and 0.9309 respectively. This predictive tool is simple and user friend to utilize and can be helpful for petroleum engineers to estimate interfacial tension between hydrocarbons and brine.Rouhibakhsh, K., Darvish, H., Sabzgholami, H., Goodarzi, M.S., 2018. Application of ANFIS-GA as a novel and accurate tool for estimation of interfacial tension of carbon dioxide and hydrocarbon. Petroleum Science and Technology 36, 1143-1149. the recent years, the enhancement oil recovery processes become the one of the interesting topics in petroleum engineering because of declination of oil reservoirs. One of the most popular processes is the carbon dioxide injection that has special importance because of its environmentally friendly and high efficiency of displacement. The interfacial tension (IFT) between carbon dioxide and hydrocarbon is known as a key parameter in this process so in the present investigation the Adaptive neuro-fuzzy inference system (ANFIS) was coupled with Genetic Algorithm (GA) to create a novel tool for prediction IFT between carbon dioxide and hydrocarbon in terms of temperature, pressure, molecular weight of alkane, gas and liquid densities. The outputs of predicting model were compared with experimental IFT statistically and graphically. The comparisons showed that predicting model has acceptable accuracy in prediction of IFT of hydrocarbon and carbon dioxide.Rousaki, A., Vargas, E., Vázquez, C., Aldazábal, V., Bellelli, C., Carballido Calatayud, M., Hajduk, A., Palacios, O., Moens, L., Vandenabeele, P., 2018. On-field Raman spectroscopy of Patagonian prehistoric rock art: Pigments, alteration products and substrata. TrAC Trends in Analytical Chemistry 105, 338-351. extensive in situ Raman spectroscopic campaign was performed on archaeological sites in three different provinces in Patagonia, Argentina (Neuquén, Río Negro and Chubut). 16 open air shelters located in different environments (forests, ecotones, steppes) were investigated and interpreted in terms of pigments used and the identification of substrata. Special attention was given to the alteration products and accretions that were found on the rock art paintings of the shelters and on the surface of the rock walls, as they can affect and damage this magnificent works of art. Haematite (α-Fe2O3) was the main chromophore that was found on the red paintings of the most of the shelters studied. The green earth glauconite, was identified only in one case, by using a red (785?nm) and a green laser (532?nm). Other minerals and silicates were found on the coloured areas but also on the rock support. Calcite (CaCO3) and gypsum (CaSO4???2H2O) crystallization was identified on the paintings, crusts and rock surfaces, in combination or alone, and are associated with weathering. In some cases the shelters were so severely degraded that no Raman signal of pigments and/or other components could be retrieved. Calcium oxalates were also detected in several figures and motifs in different shelters.Ruwoldt, J., Subramanian, S., Simon, S., Oschmann, H., Sj?blom, J., 2018. Asphaltene fractionation based on adsorption onto calcium carbonate: Part 3. Effect of asphaltenes on wax crystallization. Colloids and Surfaces A: Physicochemical and Engineering Aspects 554, 129-141. fractionation procedures were developed and tested in two preceding articles (doi: , doi: ), and asphaltene fractions were characterized in terms of composition, adsorption and self-aggregation properties. In this article, the effect of asphaltene fraction on wax crystallization was studied. Asphaltene fractionation on calcium carbonate was developed further to a column separation procedure, which yielded asphaltene fractions with even larger differences according to FTIR analysis. Wax crystallization was studied using differential scanning calorimetry (DSC), cross-polarized microscopy (CPM), rheometry, and pour point tests (PPT). Asphaltenes were found to change wax crystal morphology and decrease gel yield strength with increasing concentration. The effect on wax appearance temperature (WAT) was generally less. The greatest effect on WAT and pour point was made by bulk asphaltenes, which is the lowest polarity fraction from separation on calcium carbonate. Irreversibly adsorbed asphaltenes, containing significant amounts of carbonyl, carboxylic or derivative groups, induced the largest changes in wax crystal morphology. Still, high pour point and gel yield strength indicated low performance for this fraction. Overall, wax inhibition performance tended to be best for asphaltene fractions with low solubility and mixed functional groups. In isothermal titration calorimetry (ITC), unfractionated whole asphaltenes interacted more strongly with crystallized wax than asphaltene fractions bulk and irreversibly adsorbed. The findings indicate that wax crystallization is influenced the most by an ensemble of asphaltenes with different functional groups, rather than groups with more distinct properties.Ryb, U., Eiler, J.M., 2018. Oxygen isotope composition of the Phanerozoic ocean and a possible solution to the dolomite problem. Proceedings of the National Academy of Sciences 115, 6602-6607.: The elemental and isotopic compositions of seawater have evolved throughout Earth’s history, in tandem with major climatic, tectonic and biologic events, including the emergence and diversification of life. Over geological timescales, the oxygen isotope composition of seawater reflects a global balance between mineral–rock reactions occurring at the Earth’s surface (weathering and sedimentation) and crustal (hydrothermal alteration) environments. We put constraints on the oxygen isotope composition of seawater throughout the Phanerozoic and demonstrate that this value has remained stable. This stability suggests that the fluxes of globally averaged oxygen isotope exchange, associated with weathering and hydrothermal alteration reactions, have remained proportional through time and is consistent with the hypothesis that a steady-state balance exists between seafloor hydrothermal activity and surface weathering.Abstract: The 18O/16O of calcite fossils increased by ～8‰ between the Cambrian and present. It has long been controversial whether this change reflects evolution in the δ18O of seawater, or a decrease in ocean temperatures, or greater extents of diagenesis of older strata. Here, we present measurements of the oxygen and ?clumped” isotope compositions of Phanerozoic dolomites and compare these data with published oxygen isotope studies of carbonate rocks. We show that the δ18O values of dolomites and calcite fossils of similar age overlap one another, suggesting they are controlled by similar processes. Clumped isotope measurements of Cambrian to Pleistocene dolomites imply crystallization temperatures of 15–158 °C and parent waters having δ18OVSMOW values from ?2 to +12‰. These data are consistent with dolomitization through sediment/rock reaction with seawater and diagenetically modified seawater, over timescales of 100 My, and suggest that, like dolomite, temporal variations of the calcite fossil δ18O record are largely driven by diagenetic alteration. We find no evidence that Phanerozoic seawater was significantly lower in δ18O than preglacial Cenozoic seawater. Thus, the fluxes of oxygen–isotope exchange associated with weathering and hydrothermal alteration reactions have remained stable throughout the Phanerozoic, despite major tectonic, climatic and biologic perturbations. This stability implies that a long-term feedback exists between the global rates of seafloor spreading and weathering. We note that massive dolomites have crystallized in pre-Cenozoic units at temperatures >40 °C. Since Cenozoic platforms generally have not reached such conditions, their thermal immaturity could explain their paucity of dolomites.Sachsenhofer, R.F., Popov, S.V., Coric, S., Mayer, J., Misch, D., Morton, M.T., Pupp, M., Rauball, J., Tari, G., 2018. Paratethyan petroleum source rocks: An overview. Journal of Petroleum Geology 41, 219-245. Paratethys area extends from Central Europe to the borders of the Caspian Sea in Central Asia and hosts a significant number of petroleum provinces, many of which have been charged by Eocene to Miocene source rocks of supra‐regional significance. These include highly oil‐prone Middle Eocene marls and limestones in the Eastern Paratethys (Kuma Formation and equivalents) which are several tens of metres thick. Estimates of the source potential index (SPI) indicate that the Kuma Formation in the northern Caucasus and the Rioni Basin (Georgia) may generate 1 to 2 tons of hydrocarbons per square metre (tHC/m2). This implies that the Kuma Formation may also be an important and additional source rock in the eastern Black Sea. Oligocene and Lower Miocene pelitic rocks (Maikop Group and equivalents) are considered to be the most important source rocks in the Paratethys. Vertical variations in source potential record different stages of basin isolation that reached a maximum during the Early Oligocene (NP23) Solenovian Event. However major variations exist between different sub‐basins in the Central and the Eastern Paratethys. In the Central Paratethys, the highest quality source rocks occur in the Carpathian Basin where the Menilite Formation, several hundreds of metres thick, can generate up to 10 tHC/m2. Locally the Menilite Formation is about 1500 m thick and continues into the Lower Miocene. In these settings, the Menilite Formation can generate approximately 70 tHC/m2. In the Alpine Foreland Basin (Sch?neck and Eggerding Formations) and the Pannonian Basin (Tard Clay Formation), oil‐prone source rocks are restricted to the Lower Oligocene. In the Eastern Paratethys, the best source rock intervals of the Maikop Group are typically associated with the Early Oligocene Solenovian Event. By contrast, with the exception of the Kura Basin in Azerbaijan, the potential of Upper Oligocene and Lower Miocene rocks is often limited. In total, the Maikop Group may generate up to 2 tHC/m2 in the North Caucasus area and 4 tHC/m2 in the Rioni Basin. A particular source rock facies is found in the Western Black Sea where diatomaceous rocks with good oil potential accumulated in the Kaliakra Canyon during Early Miocene time. This facies may generate up to 8 tHC/m2, but is probably limited to shelf‐break canyons. Middle and Upper Miocene rocks are the main source for oil and thermogenic gas in the Pannonian Basin System, and also contributed to thermogenic hydrocarbons in the Moesian Platform and the South Caspian Basin. In addition, Upper Oligocene and Miocene rocks are the source for microbial gas in several basins including the Alpine and Carpathian foredeeps. Sahoo, S.K., Marín‐Moreno, H., North, L.J., Falcon‐Suarez, I., Madhusudhan, B.N., Best, A.I., Minshull, T.A., 2018. Presence and consequences of coexisting methane gas with hydrate under two phase water‐hydrate stability conditions. Journal of Geophysical Research: Solid Earth 123, 3377-3390. Methane hydrate saturation estimates from remote geophysical data and borehole logs are needed to assess the role of hydrates in climate change, continental slope stability, and energy resource potential. Here we present laboratory hydrate formation/dissociation experiments in which we determined the methane hydrate content independently from pore pressure and temperature and from electrical resistivity. Using these laboratory experiments, we demonstrate that hydrate formation does not take up all the methane gas or water even if the system is under two phase water?hydrate stability conditions and gas is well distributed in the sample. The experiment started with methane gas and water saturations of 16.5% and 83.5%, respectively; during the experiment, hydrate saturation proceeded up to 26% along with 12% gas and 62% water remaining in the system. The coexistence of hydrate and gas is one possible explanation for discrepancies between estimates of hydrate saturation from electrical and acoustic methods. We suggest that an important mechanism for this coexistence is the formation of a hydrate film enveloping methane gas bubbles, trapping the remaining gas inside.Salerno, J.L., Little, B., Lee, J., Hamdan, L.J., 2018. Exposure to crude oil and chemical dispersant may impact marine microbial biofilm composition and steel corrosion. Frontiers in Marine Science 5, 196. doi: 110.3389/fmars.2018.00196. release of hydrocarbons and chemical dispersant in marine environments may disrupt benthic ecosystems, including artificial reefs, formed by historic steel shipwrecks, and their associated organisms. Experiments were performed to determine the impacts of crude oil, dispersed crude oil, and dispersant on the community structure and function of microorganisms in seawater (SW) and biofilms formed on carbon steel, a common ship hull construction material. Steel corrosion was also monitored to illustrate how oil spills may impact preservation of steel shipwrecks. Microcosms were filled with seawater (SW) and incubated at 4?C. Carbon steel disks (CSDs) were placed in each tank, and tanks were amended with crude oil and/or dispersant or no treatment. SW and CSD biofilms were sampled biweekly for genetic analysis using Illumina sequencing of 16S ribosomal RNA gene amplicons. Predicted and sequenced bacterial metagenomes were analyzed to examine impacts of oil and dispersant on metabolic function. Gammaproteobacteria, Alphaproteobacteria, and Flavobacteriia dominated SW and biofilms. Bacterial community structure differed significantly between treatments for SW and biofilms. OTUs affiliated with known (Pseudomonas) and potential (Marinomonas) hydrocarbon-degraders were roughly twice as abundant in biofilms treated with oil and dispersed oil, and steel corrosion of CSDs in these treatments was higher compared to control and dispersant treatments. OTUs affiliated with the Rhodobacteraceae family (biofilm formers and potential oil degraders) were less abundant in the dispersant treatment compared to other treatments in biofilm and SW samples, but OTUs affiliated with the Pseudoalteromonas genus (biofilm formers and proposed hydrocarbon degraders) were more abundant in dispersant-treated biofilms. Overall, functional gene analyses revealed a decrease in genes (predicted using PICRUSt and observed in sequenced metagenomes) associated with hydrocarbon degradation in dispersant-treated biofilms. This study indicates that exposure to oil and dispersant could disrupt the composition and metabolic function of biofilms colonizing metal hulls, as well as corrosion processes, potentially compromising shipwrecks as ecological and historical resources.Sánchez-Illana, ?., Pérez-Guaita, D., Cuesta-García, D., Sanjuan-Herráez, J.D., Vento, M., Ruiz-Cerdá, J.L., Quintás, G., Kuligowski, J., 2018. Model selection for within-batch effect correction in UPLC-MS metabolomics using quality control - Support vector regression. Analytica Chimica Acta 1026, 62-68. performance liquid chromatography – mass spectrometry (UPLC-MS) is increasingly being used for untargeted metabolomics in biomedical research. Complex matrices and a large number of samples per analytical batch lead to gradual changes in the instrumental response (i.e. within-batch effects) that reduce the repeatability and reproducibility and limit the power to detect biological responses. A strategy for within-batch effect correction based on the use of quality control (QC) samples and Support Vector Regression (QC-SVRC) with a radial basis function kernel was recently proposed. QC-SVRC requires the optimization of three hyperparameters that determine the accuracy of the within-batch effects elimination: the tolerance threshold (ε), the penalty term (C) and the kernel width (γ). This work compares three widely used strategies for QC-SVRC hyperparameter optimization (grid search, random search and particle swarm optimization) using a UPLC-MS data set containing 193 urine injections as model example. Results show that QC-SVRC is robust to hyperparameter selection and that a pre-selection of C and ε, followed by optimization of γ is competitive in terms of accuracy, precision and number of function evaluations with full grid analysis, random search and particle swarm optimization. The QC-SVRC optimization procedure can be regarded as a useful non-parametric tool for efficiently complementing alternative approaches such as QC-robust splines correction (RSC).Sanguinito, S., Goodman, A.L., Sams III, J.I., 2018. CO2-SCREEN tool: Application to the Oriskany Sandstone to estimate prospective CO2 storage resource. International Journal of Greenhouse Gas Control 75, 180-188. ability to accurately predict the CO2 storage resource in saline formations is important to make high-level, energy-related government policy and business decisions. CO2-SCREEN (Storage prospeCtive Resource Estimation Excel aNalysis) is a tool developed by the United States Department of Energy ? National Energy Technology Laboratory (US-DOE-NETL) to screen saline formations for prospective CO2 storage resources. CO2-SCREEN uses DOE methods and equations to serve as a consistent mechanism for calculating prospective CO2 storage resources. CO2-SCREEN is comprised of two files: an Excel file used for inputs and outputs and a GoldSim Player file used to run Monte Carlo simulations. CO2-SCREEN requires input of physical geologic parameters (i.e. thickness, porosity) as well as efficiency factor ranges (i.e. net-to-gross thickness) to calculate a mass storage estimate. An application of CO2-SCREEN is demonstrated here using well log data from the Oriskany Sandstone portion in Pennsylvania. The Oriskany Sandstone is divided into 20?km x 20?km grid cells in which 151 cells contain well log data. CO2-SCREEN calculates prospective CO2 storage resource for each grid cell based on the well log data and uses lithology and depositional environment information for efficiency factor ranges. The Oriskany Sandstone CO2 storage resource estimate for Pennsylvania, calculated by CO2-SCREEN, ranges from 0.07 to 1.28 gigatons (Gt) with a P50 value of 0.32 Gt. This resource assessment analysis is done to demonstrate the use of CO2-SCREEN and results are comparable to previous studies which encourages the application of CO2-SCREEN to other saline formations and warrants exploring the expansion of this tool to assess the CO2 storage resource in other formations such as shale and depleted oil and gas reservoirs.Santerre, C., Vallet, N., Touboul, D., 2018. Fingerprints of flower absolutes using supercritical fluid chromatography hyphenated with high resolution mass spectrometry. Journal of Chromatography B 1092, 1-6. fluid chromatography hyphenated with high resolution mass spectrometry (SFC-HRMS) was developed for fingerprint analysis of different flower absolutes commonly used in cosmetics field, especially in perfumes. Supercritical fluid chromatography-atmospheric pressure photoionization-high resolution mass spectrometry (SFC-APPI-HRMS) technique was employed to identify the components of the fingerprint. The samples were separated with a porous graphitic carbon (PGC) Hypercarb? column (100?mm?×?2.1?mm, 3?μm) by gradient elution using supercritical CO2 and ethanol (0.0–20.0?min (2–30% B), 20.0–25.0?min (30% B), 25.0–26.0?min (30–2% B) and 26.0–30.0?min (2% B)) as mobile phase at a flow rate of 1.5?mL/min. In order to compare the SFC fingerprints between five different flower absolutes: Jasminum grandiflorum absolutes, Jasminum sambac absolutes, Narcissus jonquilla absolutes, Narcissus poeticus absolutes, Lavandula angustifolia absolutes from different suppliers and batches, the chemometric procedure including principal component analysis (PCA) was applied to classify the samples according to their genus and their species. Consistent results were obtained to show that samples could be successfully discriminated.Sawada, H., Isozaki, Y., Sakata, S., Hirata, T., Maruyama, S., 2018. Secular change in lifetime of granitic crust and the continental growth: A new view from detrital zircon ages of sandstones. Geoscience Frontiers 9, 1099-1115. ages of detrital zircons were newly dated for 4 Archean sandstones from the Pilbara craton in Australia, Wyoming craton in North America, and Kaapvaal craton in Africa. By using the present results with previously published data, we compiled the age spectra of detrital zircons for 2.9, 2.6, 2.3, 1.0, and 0.6?Ga sandstones and modern river sands in order to document the secular change in age structure of continental crusts through time. The results demonstrated the following episodes in the history of continental crust: (1) low growth rate of the continents due to the short cycle in production/destruction of granitic crust during the Neoarchean to Paleoproterozoic (2.9–2.3?Ga), (2) net increase in volume of the continents during Paleo- to Mesoproterozoic (2.3–1.0?Ga), and (3) net decrease in volume of the continents during the Neoproterozoic and Phanerozoic (after 1.0?Ga). In the Archean and Paleoproterozoic, the embryonic continents were smaller than the modern continents, probably owing to the relatively rapid production and destruction of continental crust. This is indeed reflected in the heterogeneous crustal age structure of modern continents that usually have relatively small amount of Archean crusts with respect to the post-Archean ones. During the Mesoproterozoic, plural continents amalgamated into larger ones comparable to modern continental blocks in size. Relatively older crusts were preserved in continental interiors, whereas younger crusts were accreted along continental peripheries. In addition to continental arc magmatism, the direct accretion of intra-oceanic island arc around continental peripheries also became important for net continental growth. Since 1.0?Ga, total volume of continents has decreased, and this appears consistent with on-going phenomena along modern active arc-trench system with dominant tectonic erosion and/or arc subduction. Subduction of a huge amount of granitic crusts into the mantle through time is suggested, and this requires re-consideration of the mantle composition and heterogeneity.Scheib, C.L., Li, H., Desai, T., Link, V., Kendall, C., Dewar, G., Griffith, P.W., M?rseburg, A., Johnson, J.R., Potter, A., Kerr, S.L., Endicott, P., Lindo, J., Haber, M., Xue, Y., Tyler-Smith, C., Sandhu, M.S., Lorenz, J.G., Randall, T.D., Faltyskova, Z., Pagani, L., Danecek, P., O’Connell, T.C., Martz, P., Boraas, A.S., Byrd, B.F., Leventhal, A., Cambra, R., Williamson, R., Lesage, L., Holguin, B., Ygnacio-De Soto, E., Rosas, J., Metspalu, M., Stock, J.T., Manica, A., Scally, A., Wegmann, D., Malhi, R.S., Kivisild, T., 2018. Ancient human parallel lineages within North America contributed to a coastal expansion. Science 360, 1024-1027.: Little is known regarding the first people to enter the Americas and their genetic legacy. Genomic analysis of the oldest human remains from the Americas showed a direct relationship between a Clovis-related ancestral population and all modern Central and South Americans as well as a deep split separating them from North Americans in Canada. We present 91 ancient human genomes from California and Southwestern Ontario and demonstrate the existence of two distinct ancestries in North America, which possibly split south of the ice sheets. A contribution from both of these ancestral populations is found in all modern Central and South Americans. The proportions of these two ancestries in ancient and modern populations are consistent with a coastal dispersal and multiple admixture events.Editor's Summay. Founder effects in modern populations: The genomes of ancient humans can reveal patterns of early human migration (see the Perspective by Achilli et al.). Iceland has a genetically distinct population, despite relatively recent settlement (～1100 years ago). Ebenesersdóttir et al. examined the genomes of ancient Icelandic people, dating to near the colonization of Iceland, and compared them with modernday Icelandic populations. The ancient DNA revealed that the founders had Gaelic and Norse origins. Genetic drift since the initial settlement has left modern Icelanders with allele frequencies that are distinctive, although still skewed toward those of their Norse founders. Scheib et al. sequenced ancient genomes from the Channel Islands of California, USA, and Ontario, Canada. The ancient Ontario population was similar to other ancient North Americans, as well as to modern Algonquian-speaking Native Americans. In contrast, the California individuals were more like groups that now live in Mexico and South America. It appears that a genetic split and population isolation likely occurred during the Ice Age, but the peoples remixed at a later date.Schicks, J.M., Strauch, B., Heeschen, K.U., Spangenberg, E., Luzi‐Helbing, M., 2018. From microscale (400?μl) to macroscale (425?L): Experimental investigations of the CO2/N2‐CH4 exchange in gas hydrates simulating the I?nik Sikumi Field Trial. Journal of Geophysical Research: Solid Earth 123, 3608-3620. 2012 the production of CH4 from hydrate-bearing sediments via CO2 injection was conducted in the framework of the I?nik Sikumi Field Trial in Alaska, USA. In order to preserve the injectivity by avoiding a formation of CO2 hydrate in the near-well region, a mixture containing 77?mol% N2 and 23?mol% CO2 was chosen. The interpretation of the complex test results was difficult, and the nature of the interaction between the N2-CO2 mixture and the initial CH4 hydrate could not be clarified. In this study we present the results of our experimental investigations simulating the I?nik Sikumi Field Trial at different scales. We conducted (1) in situ Raman spectroscopic investigations to study the exchange process of the guest molecules in the hydrate phase on a molecular level in a flow?through pressure cell with a volume of 0.393?ml, (2) batch experiments with pure hydrates and hydrate?bearing sediments in pressure cells with volumes of 420?ml, and (3) the injection of a CO2-N2 mixture into a hydrate?bearing sediment in a large-scale reservoir simulator with a total volume of 425?L. The results indicate a dissociation of the initial CH4 hydrate rather than an exchange reaction. The formation of a secondary mixed hydrate phase may occur, but this process strongly depends on the local composition of the gas phase and the pressure at given temperature.Schmitt Rahner, M., Halisch, M., Peres Fernandes, C., Weller, A., Sampaio Santiago dos Santos, V., 2018. Fractal dimensions of pore spaces in unconventional reservoir rocks using X-ray nano- and micro-computed tomography. Journal of Natural Gas Science and Engineering 55, 298-311. attention has been paid to the development of unconventional reservoir fields due to the availability of such resources worldwide. The heterogeneities throughout the pore space structure in a rock and their effects on the occurrence of gas and oil can be quantitatively analysed using fractal theory. This study focuses on the investigation of the fractal dimension (FD) in shale and tight gas sandstones (TGS) from Brazilian oil and gas fields using 3-D X-ra nano- and micro-computed tomography. Obtaining the broad size distribution of pore space structures in unconventional reservoir rocks using 3-D images is challenging due to the multiscale characteristics of the rocks. Thus, sample images were acquired with two voxel size/resolutions (0.064?μm and from 0.46 to 1.20?μm). Very small pores (ganglia), main pore networks and organic matter grains were observed as segmented structures within sample sets for which the FD was assessed and quantified. Box-counting (BC) and pore size distribution (PSD) approaches were applied. The average FD values ranged from 1.78 to 2.59 in shale and from 2.36 to 2.46 in TGS. Correlations of the FD with the experimentally acquired specific surface area, porosity and permeability related petrophysical properties, relevant to the quantitative modelling of gas transport in unconventional reservoirs, were established. The pore scale morphologies described by the FD from 3-D X-ray CT images help on the foundation for further research in shale/tight gas sandstones.Schneider, A., Panieri, G., Lepland, A., Consolaro, C., Crémière, A., Forwick, M., Johnson, J.E., Plaza-Faverola, A., Sauer, S., Knies, J., 2018. Methane seepage at Vestnesa Ridge (NW Svalbard) since the Last Glacial Maximum. Quaternary Science Reviews 193, 98-117. proxies in the geological record offshore NW Svalbard track shallow subseafloor diagenesis and seafloor methane seepage during the Last Glacial Maximum (LGM) extent and the disintegration of the Svalbard Barents Sea Ice Sheet (SBIS). Vestnesa Ridge, located at 79°N and in 1200?m water depth, is one of the northernmost known active methane seep sites and is characterised by a subseafloor fluid flow system, numerous seafloor pockmarks and gas flares in the water column. In this study, we develop a Late Pleistocene and Holocene stratigraphic framework, use stable oxygen and carbon isotope signatures (δ18O, δ13C) of benthic and planktic foraminifera, the mineralogical and carbon isotope composition of methane-derived authigenic carbonate (MDAC) and sediment geochemical data of ten sediment cores to assess methane seepage variability on Vestnesa Ridge.The studied cores cover the age range between 31.9 and 10?cal ka BP and record 32 negative δ13C excursions in benthic and planktic foraminifera with amplitudes down to ?29 ‰ VPDB. These δ13C excursions are often associated with elevated Ca/Ti and Sr/Ti elemental ratios in sediments and MDAC nodules. The precipitation of MDAC overgrowth on foraminiferal tests explains most of the negative δ13C excursions. In this dataset, the oldest recorded methane emission episodes on Vestnesa Ridge occurred between the LGM (24–23.5?cal ka BP) and Heinrich Event 1 (HE 1; 17.7–16.8?cal ka BP).Geological indicators for past subseafloor methane cycling and seafloor methane seepage, such as negative foraminiferal δ13C excursions, MDAC nodules, and elevated Sr/Ti elemental ratios recorded in post-LGM sediments, possibly represent vertical migration of the sulphate-methane transition zone (SMTZ) and post-date sedimentation by up to 13.4 ka. However, it is important to note that indications of post-LGM seafloor methane seepage at Vestnesa Ridge also correspond to the established methane efflux chronology for the adjacent Barents Sea shelf, implying that glacio-isostatic adjustments and associated re-activation of pre-existing deep-seated faults after disintegration of the SBIS are likely important controlling factors on fluid migration towards the seafloor.Schwarzbauer, J., Stock, F., Brückner, H., Dsikowitzky, L., Krichel, M., 2018. Molecular organic indicators for human activities in the Roman harbor of Ephesus, Turkey. Geoarchaeology 33, 498-509. organic‐geochemical analyses were applied to sediment core samples from the Roman harbor of Ephesus that date to the open, protected, and post‐harbor time periods. Screening analyses revealed a substance spectrum comprising n‐alkanes, fatty acids, polycyclic aromatic hydrocarbons (PAHs), and selected terpenoids. All these substance groups have been quantified and show a significant increase of concentration in the samples affected by the intensive use of Ephesus’ Roman harbor. However, a unique indicator substance or a single anthropogenic marker compound directly reflecting ancient harbor activities has not been identified. Nonetheless, systematic changes in the patterns of some major organic substance groups (PAHs, fatty acids, and n‐alkanes) point to a significant change in the composition of organic matter (OM), which might reflect increased anthropogenic impacts during Ephesus’ flourishing period. These observations are likely related to enhanced anthropogenic use of natural products, such as waxes, and subsequent discharge by municipal sewage or the direct use and emission of such products in the harbor area. This study clearly demonstrates the usefulness of indicative organic compounds and changes in their patterns through time to detect the activities of ancient civilizations. This approach can be transferred to other sedimentary geoarchives associated with former settlement activities. Schwieterman, E.W., Kiang, N.Y., Parenteau, M.N., Harman, C.E., DasSarma, S., Fisher, T.M., Arney, G.N., Hartnett, H.E., Reinhard, C.T., Olson, S.L., Meadows, V.S., Cockell, C.S., Walker, S.I., Grenfell, J.L., Hegde, S., Rugheimer, S., Hu, R., Lyons, T.W., 2018. Exoplanet biosignatures: A review of remotely detectable signs of life. Astrobiology 18, 663-708. the coming years and decades, advanced space- and ground-based observatories will allow an unprecedented opportunity to probe the atmospheres and surfaces of potentially habitable exoplanets for signatures of life. Life on Earth, through its gaseous products and reflectance and scattering properties, has left its fingerprint on the spectrum of our planet. Aided by the universality of the laws of physics and chemistry, we turn to Earth's biosphere, both in the present and through geologic time, for analog signatures that will aid in the search for life elsewhere. Considering the insights gained from modern and ancient Earth, and the broader array of hypothetical exoplanet possibilities, we have compiled a comprehensive overview of our current understanding of potential exoplanet biosignatures, including gaseous, surface, and temporal biosignatures. We additionally survey biogenic spectral features that are well known in the specialist literature but have not yet been robustly vetted in the context of exoplanet biosignatures. We briefly review advances in assessing biosignature plausibility, including novel methods for determining chemical disequilibrium from remotely obtainable data and assessment tools for determining the minimum biomass required to maintain short-lived biogenic gases as atmospheric signatures. We focus particularly on advances made since the seminal review by Des Marais et al. The purpose of this work is not to propose new biosignature strategies, a goal left to companion articles in this series, but to review the current literature, draw meaningful connections between seemingly disparate areas, and clear the way for a path forward.Sciarrone, D., Schepis, A., Zoccali, M., Donato, P., Vita, F., Creti, D., Alpi, A., Mondello, L., 2018. Multidimensional gas chromatography coupled to combustion-isotope ratio mass spectrometry/quadrupole MS with a low-bleed ionic liquid secondary column for the authentication of truffles and products containing truffle. Analytical Chemistry 90, 6610-6617. are among the most expensive foods available in the market, usually used as flavoring additives for their distinctive aroma. The most valuable species is Tuber magnatum Pico, better known as “Alba white truffle”, in which bis(methylthio)methane is the key aroma compound. Given the high economical value of genuine white truffles, analytical approaches are required to be able to discriminate between natural or synthetic truffle aroma. Gas chromatography coupled to combustion-isotope ratio mass spectrometry (GC-C-IRMS), exploiting the 13C/12C ratio abundance of the key flavorings compounds in foods, has been a recognized technique for authenticity and traceability purposes; however, a number of issues have greatly limited its widespread use so far. In the present research, a high-efficiency HS-SPME MDGC-C-IRMS with simultaneous quadrupole MS detection has been applied for the evaluation of bis(methylthio)methane, resolving the coelution occurring with other components. With the aim to minimize the effect of column bleeding on δ13C measurement, a medium polarity ionic liquid-based stationary phase was preferred to a polyethylene glycol one, as the secondary column. In total, 24 genuine white truffles harvested in Italy were analyzed, attaining a δ13C values between ?42.6‰ and ?33.9‰, with a maximum standard deviation lower than 0.7‰. Two commercial intact truffles and 14 commercial samples of pasta, sauce, olive oil, cream, honey, and fresh cheese flavored with truffle aroma were analyzed, and the results from δ13C measurement were evaluated in comparison with those of genuine “white truffle” range and commercial synthetic bis(methylthio)methane standard.Seabrook, S., De Leo, F., Baumberger, T., Raineault, N., Thurber, A.R., 2018. Heterogeneity of methane seep biomes in the Northeast Pacific. Deep Sea Research Part II: Topical Studies in Oceanography 150, 195-209. seeps provide biogeochemical and microbial heterogeneity in deep-sea habitats. In the Northeast (NE) Pacific Ocean recent studies have found an abundance of seeps at varying spatial separations and within distinct biogeochemical environments ranging in oxygen, depth, and temperature. Here, we examine 8 newly discovered seeps and 2 known seeps covering 800 km and varying across 2000m water depth to identify: (1) novel megafaunal communities in this geographical region; (2) variations in the microbiome of seep habitats across the margin; (3) spatial and biogeochemical drivers of microbial diversity at seeps. In addition to authigenic carbonates, clam beds, microbial mats, and exposed hydrates - we also observed Siboglinidae tube worm bushes and an anomalous deep-sea barnacle adding to the overall habitats known from the NE Pacific. The microbial communities showed high variability in their spatial distribution and community structure. The seep communities formed distinct groups that included multiple groups of anaerobic methane oxidizing Archaea (ANME; 1, 2ab, 2c, and 3), often co-occurring within one site – however, there were also other sites with clearly dominant members (e.g. ANME-1s at Nehalem Bank). Sulfide oxidizers were dominated by the non-mat forming Campylobacterales and even though vertical gradients in redox potential typify seep sediments, in two cases there was not a significant change in community structure across the top 5 cm of sediment. We posit that these patterns were driven by ‘bubble-turbation,’ and bioirrigation by megafauna. A surprising latitudinal trend was observed in species diversity and richness with increasing richness significantly correlated to increasing latitude. Overall, our results demonstrate that heterogeneity is ubiquitous in the seep biome, spanning all faunal classes, and that the understanding of seeps and the drivers of the community structure can be improved by studying seeps at a range of spatial scales.Segev, A., Sass, E., Schattner, U., 2018. Age and structure of the Levant basin, Eastern Mediterranean. Earth-Science Reviews 182, 233-250. parts of the Mediterranean were formed during the Mesotethys Ocean opening and subsequently became land-locked in the midst of the Africa-Eurasia plate convergence. Since the Neogene, this convergence has concealed key sections of the original basins. Previous studies widely agree that the easternmost part of the Mediterranean, the Levant Basin, opened during the Permian to Early Jurassic (PJ) and accordingly explain the architecture of the basin and its margins. However, since the PJ model was suggested in the late 1990’s a flood of new evidence has arrived since the hydrocarbon exploration, some of which do not fit in with the PJ model, and some remain unexplained. The current research re-examines the old and new evidence from the Levant basin, its margins, the surrounding landmass, the adjacent Eratosthenes Seamount and the eastern part of the Herodotus Basin. The integration of geological and geophysical data suggests that the Levant Basin formed ~100 Myr later than previously thought, i.e., during the Cretaceous. Its opening was triggered by the ‘Levant-Nubia' mantle plume that induced a sequence of wide-spread Ocean Island Basalt volcanism. The resulting crustal updoming and stretching led to the breakup of the Levant landmass since ~141?Ma, and drifting of the Eratosthenes Seamount since ~125?Ma. Back-arc extension shaped the Levant Basin as a hybrid crust comprising continental slivers intervened by oceanic patches. The basin opened during the Long Normal Cretaceous Polarity Chrons between ~122 and ~84?Ma, and therefore it does not show any magnetic lineation. The opening of the Levant basin occurred while the Herodotus basin floor subducted eastward under the Eratosthenes Seamount. The subduction hinge did a roll-back and facilitated the Seamount drifting. The Seamount absorbed intensive volcanism while chasing the subduction roll-back and sliding between two Subduction-Transform Edge Propagator (STEP) faults that bounded the stretching Levant back-arc basin. The Turonian-Maastrichtian compression stress regime, or inversion, halted the extension of the Levant Basin, stagnated its hybrid fabric, and prevented the development of a spreading center. The evolutionary scenario suggested here is a game changer for future exploration in the Levant and may serve as a global analog for the formation of marginal seas.Segschneider, J., Schneider, B., Khon, V., 2018. Climate and marine biogeochemistry during the Holocene from transient model simulations. Biogeosciences 15, 3243-3266. and marine biogeochemistry changes over the Holocene are investigated based on transient global climate and biogeochemistry model simulations over the last 9500 years. The simulations are forced by accelerated and non-accelerated orbital parameters, respectively, and atmospheric pCO2, CH4, and N2O. The analysis focusses on key climatic parameters of relevance to the marine biogeochemistry, and on the physical and biogeochemical processes that drive atmosphere–ocean carbon fluxes and changes in the oxygen minimum zones (OMZs). The simulated global mean ocean temperature is characterized by a mid-Holocene cooling and a late Holocene warming, a common feature among Holocene climate simulations which, however, contradicts a proxy-derived mid-Holocene climate optimum. As the most significant result, and only in the non-accelerated simulation, we find a substantial increase in volume of the OMZ in the eastern equatorial Pacific (EEP) continuing into the late Holocene. The concurrent increase in apparent oxygen utilization (AOU) and age of the water mass within the EEP OMZ can be attributed to a weakening of the deep northward inflow into the Pacific. This results in a large-scale mid-to-late Holocene increase in AOU in most of the Pacific and hence the source regions of the EEP OMZ waters. The simulated expansion of the EEP OMZ raises the question of whether the deoxygenation that has been observed over the last 5 decades could be a – perhaps accelerated – continuation of an orbitally driven decline in oxygen. Changes in global mean biological production and export of detritus remain of the order of 10?%, with generally lower values in the mid-Holocene. The simulated atmosphere–ocean CO2 flux would result in atmospheric pCO2 changes of similar magnitudes to those observed for the Holocene, but with different timing. More technically, as the increase in EEP OMZ volume can only be simulated with the non-accelerated model simulation, non-accelerated model simulations are required for an analysis of the marine biogeochemistry in the Holocene. Notably, the long control experiment also displays similar magnitude variability to the transient experiment for some parameters. This indicates that also long control runs are required when investigating Holocene climate and marine biogeochemistry, and that some of the Holocene variations could be attributed to internal variability of the atmosphere–ocean systemSekine, Y., Kodama, K., Kobayashi, T., Obata, S., Chang, Y., Ogawa, N.O., Takano, Y., Ohkouchi, N., Saiki, K., Sekine, T., 2018. An experimental study on impact‐induced alterations of planetary organic simulants. Meteoritics & Planetary Science 53, 1267-1282. present study systematically investigates shock‐induced alteration of organic simulants of planetary bodies (OSPBs) as a function of peak shock pressure and temperature by impact experiments. Our results show that the composition and structure of OSPBs are unchanged upon impacts at peak pressures ≤~5 GPa and temperatures ≤~350 °C. On the other hand, these are dramatically changed upon impacts at >7–8 GPa and > ~400 °C, through loss of hydrogen‐related bonds and concurrent carbonization, regardless of the initial compositions of OSPBs. Compared with previous results on static heating of organic matter, we suggest that shock‐induced alteration cannot be distinguished from static heating only by Raman and infrared spectroscopy. Our experimental results would provide a proxy indicator for assessing degree of shock‐induced alteration of organic matter contained in carbonaceous chondrites. We suggest that a remote‐sensing signature of the 3.3–3.6 μm absorption due to hydrogen‐related bonds on the surface of small bodies would be a promising indicator for the presence of less‐thermally‐altered (i.e., <350 °C) organic matter there, which will be a target for landing to collect primordial samples in sample‐return spacecraft missions, such as Hayabusa2 and OSIRIS‐REx. Senger, R., Romero, E., Marschall, P., 2018. Modeling of gas migration through low-permeability clay rock using information on pressure and deformation from fast air injection tests. Transport in Porous Media 123, 563-579. characterization of gas migration through low-permeability clay formations has been a focus of R&D programs for radioactive waste disposal, which is also of great importance for shale gas exploration, cap-rock behavior of hydrocarbon reservoirs, and CO2 sequestration. Laboratory tests have been performed on Opalinus Clay, a Mesozoic claystone that is being investigated in Switzerland as a potential host rock for the storage of nuclear waste. The laboratory program included specific water and air injections tests, as well as oedometer and isotropic compression tests. Undisturbed core samples have been retrieved from a shallow borehole in the Mont Terri Underground Research Laboratory (URL) and from a deep borehole in northern Switzerland. For the shallow cores from Mont Terri URL, largely linear-elastic deformations associated with the gas injection test could be inferred and the change in void ratio was accounted for by the pore compressibility. The corresponding change in permeability was obtained from the results of the water tests, indicating a log-linear relation between permeability and porosity. The derived porosity change and the corresponding change in permeability were implemented in the standard TOUGH2 code, which reproduced the measured gas test results using fitted water retention data derived from laboratory measurements. Similar air injection tests performed on Opalinus Clay cores from the borehole at greater depth showed overall similar behavior, but at lower porosities, lower permeability values, and lower compressibility. These cases indicated nonlinear behavior which was implemented using an effective stress-dependent porosity change and the associated change in permeability. In addition, the anisotropy associated with the bedding planes of the clay formation was considered by assuming different properties for “soft” and “hard” layers to account for storage capacity for the injected gas prior to gas breakthrough. The computed change in the overall porosity could be compared to the measured axial deformation during the gas injection test and was used for calibration of the parameters describing the relationship between the effective stress and porosity, as well as the corresponding change in permeability and capillary pressure.Sengupta, A., Pakrasi, H.B., Wangikar, P.P., 2018. Recent advances in synthetic biology of cyanobacteria. Applied Microbiology and Biotechnology 102, 5457-5471. are attractive hosts that can be engineered for the photosynthetic production of fuels, fine chemicals, and proteins from CO2. Moreover, the responsiveness of these photoautotrophs towards different environmental signals, such as light, CO2, diurnal cycle, and metals make them potential hosts for the development of biosensors. However, engineering these hosts proves to be a challenging and lengthy process. Synthetic biology can make the process of biological engineering more predictable through the use of standardized biological parts that are well characterized and tools to assemble them. While significant progress has been made with model heterotrophic organisms, many of the parts and tools are not portable in cyanobacteria. Therefore, efforts are underway to develop and characterize parts derived from cyanobacteria. In this review, we discuss the reported parts and tools with the objective to develop cyanobacteria as cell factories or biosensors. We also discuss the issues related to characterization, tunability, portability, and the need to develop enabling technologies to engineer this “green” chassis.Seyyedi, M., Tagliaferri, S., Abatzis, J., Nielsen, S.M., 2018. An integrated experimental approach to quantify the oil recovery potential of seawater and low-salinity seawater injection in North Sea chalk oil reservoirs. Fuel 232, 267-278. this study, the oil recovery potential of seawater (SW), SW with different ion compositions, low-salinity seawater (LSSW), and formation water (FW), is investigated, using chalk reservoir cores and crude oil from the North Sea. Furthermore, the impact of temperature on SW flooding performance is addressed.A series of flooding experiments were conducted at reservoir conditions (2800?psi and 60?°C), followed by spontaneous imbibition tests. Secondary SW and FW flooding led to the same oil recovery. Tertiary SW injections, performed after secondary FW flooding and secondary LSSW injection, did not lead to any extra oil recovery at 60?°C. Injecting SW at 100?°C did not lead to additional recovery either. Spiking the SO4?2 content of SW by four times, at 60?°C, did not show any additional oil production as well as increasing the concentration of Ca+2 and the Ca+2/Mg+2 ratio at 60?°C. Conversely, tertiary LSSW injection, after secondary SW injection, led to 2.5% OOIP additional oil recovery. More importantly, secondary LSSW injection, compared to the secondary SW and FW injection, led to around 8% OOIP extra oil recovery. Consistently, the results of the imbibition test showed the same trend: tertiary LSSW imbibition, after secondary SW imbibition, led to 4.25% OOIP extra oil recovery.This study, through employing chalk reservoir cores and crude oil, reveals that LSSW flooding in examples of silica containing chalk reservoirs in the North Sea, has a better oil recovery potential compared to both SW and FW flooding. This is in contrast to other published results as it will be discussed in the paper.Shah, C., Sudheer, A.K., Bhushan, R., 2018. Distribution of dissolved organic carbon in the Bay of Bengal: Influence of sediment discharge, fresh water flux, and productivity. Marine Chemistry 203, 91-101. organic carbon (DOC) plays an important role in the oceanic carbon cycle, with its distribution and variation primarily controlled by in situ productivity. The vertical and spatial distribution of DOC measured during two cruises has been investigated to decipher the processes controlling DOC in the Bay of Bengal (BoB). The terrestrial DOC flux to the BoB constitutes a significant fraction of the total DOC and has implications for the carbon budget of the northern Indian Ocean. High concentrations of DOC were observed in the northern BoB, which is primarily due to high flux of terrestrially derived fresh water from various rivers draining to the BoB. Compared to surface DOC concentration of the world oceans, BoB surface water generally has a higher DOC concentration (75–100?μM), which can be attributed to the high DOC content of the riverine flux. Stratification of surface water helps to maintain DOC content due to inhibited vertical mixing in the BoB as a result of the fresh water lens. High subsurface DOC concentration is due to the remineralisation of biogenic sinking particles brought along with the sediments. Subsurface DOC concentrations in the BoB exhibit a conspicuous decreasing trend southwards due to reduced influence of riverine biogenic flux. This study demonstrates that the average contribution of apparent oxygen utilization (AOU) to the DOC remineralisation in the BoB was ~18%.Shakun, J.D., Corbett, L.B., Bierman, P.R., Underwood, K., Rizzo, D.M., Zimmerman, S.R., Caffee, M.W., Naish, T., Golledge, N.R., Hay, C.C., 2018. Minimal East Antarctic Ice Sheet retreat onto land during the past eight million years. Nature 558, 284-287. East Antarctic Ice Sheet (EAIS) is the largest potential contributor to sea-level rise. However, efforts to predict the future evolution of the EAIS are hindered by uncertainty in how it responded to past warm periods, for example, during the Pliocene epoch (5.3 to 2.6 million years ago), when atmospheric carbon dioxide concentrations were last higher than 400 parts per million. Geological evidence indicates that some marine-based portions of the EAIS and the West Antarctic Ice Sheet retreated during parts of the Pliocene, but it remains unclear whether ice grounded above sea level also experienced retreat. This uncertainty persists because global sea-level estimates for the Pliocene have large uncertainties and cannot be used to rule out substantial terrestrial ice loss, and also because direct geological evidence bearing on past ice retreat on land is lacking. Here we show that land-based sectors of the EAIS that drain into the Ross Sea have been stable throughout the past eight million years. We base this conclusion on the extremely low concentrations of cosmogenic 10Be and 26Al isotopes found in quartz sand extracted from a land-proximal marine sediment core. This sediment had been eroded from the continent, and its low levels of cosmogenic nuclides indicate that it experienced only minimal exposure to cosmic radiation, suggesting that the sediment source regions were covered in ice. These findings indicate that atmospheric warming during the past eight million years was insufficient to cause widespread or long-lasting meltback of the EAIS margin onto land. We suggest that variations in Antarctic ice volume in response to the range of global temperatures experienced over this period—up to 2–3 degrees Celsius above preindustrial temperatures, corresponding to future scenarios involving carbon dioxide concentrations of between 400 and 500 parts per million—were instead driven mostly by the retreat of marine ice margins, in agreement with the latest models.Shang, X., Moczyd?owska, M., Liu, P., Liu, L., 2018. Organic composition and diagenetic mineralization of microfossils in the Ediacaran Doushantuo chert nodule by Raman and petrographic analyses. Precambrian Research 314, 145-159. studied microfossils and their embedding matrix minerals from chert nodules in the Ediacaran Doushantuo Formation of the Yangtze Gorges area in South China using Raman spectroscopy as well as transmitted- and polarized light microscopy. The microfossils are composed of organic carbonaceous material with weak structural organization/ordering, which indicates a low degree of thermal maturation and alteration. Raman spectral disparity of carbonaceous material among different portions (vesicle/inclusion) of microfossils reveals some differences in organic composition and structure of their precursor biological matters. The mineral phases of silica matrix that entombs the microfossils are recognized as opal-CT, cryptocrystalline quartz, and their transitional phases. Overall, Raman spectral analyses and petrographic observations document a complete and continuous sequence of silica phase transformation from opal-CT to quartz. When reconstructing the diagenetic history of sediments and mineralization process of microfossils in a localized microenvironment, the silica in pore waters precipitated preferentially at the periphery of microorganisms in the form of opal, gradually decreasing in abundance as it transformed into more stable cryptocrystalline quartz. The recrystallization took place in cryptocrystalline quartz to form grains. Authigenic fluorapatite readily precipitated in the vicinity of some microfossils and within their degraded organic fragments. While apatite was crystallizing around organisms and their biostructures, silica precipitated in the surrounding voids, inhibiting the space of potential apatite crystallization. The silicification and phosphatization of microfossils occurred in the microbial sulfate reduction (MSR) zone of the sediment column, and both were driven by the localized pH change resulting from MSR and pyrite precipitation in the microenvironment, thus facilitating the exceptional fossil preservation in the Doushantuo chert nodules.Shao, P., Wang, X., Song, Y., Li, Y., 2018. Study on the characteristics of matrix compressibility and its influence factors for different rank coals. Journal of Natural Gas Science and Engineering 56, 93-106. thoroughly understand the mechanism of permeability change and improve production in coalbed methane development, it is important to clarify the evolution characteristics and influencing factors of matrix compressibility for various coal ranks. This paper presents calculations of matrix compressibility coefficients of different rank coals through mercury intrusion porosimetry (MIP) and N2 adsorption. Furthermore, the evolution of coal material and pores based on coal rank is analyzed to study their effect on matrix compressibility coefficients. The results show that the relationship between matrix compressibility coefficients and coal rank is a cubic polynomial function, in which two inflection points are situated in the maximum vitrinite reflectance (Ro,max)?=?1.3% and 2.5%. For coals with Ro,max &lt; 1.3%, matrix compressibility coefficients increase as vitrinite and volatile matter contents increase, which may be related to the lower microhardness of vitrinite and the more random structure of aromatic carbon micells surrounded or linked by carbon functional groups, such as aliphatic chains, methoxyl and carboxylic functional groups. Moreover, the regular change of moisture content with coal rank is similar to matrix compressibility coefficients and it also plays a positive role in matrix compressibility. However, the inertinite and mineral content has a rather opposite effect on matrix compressibility. For the pore structure, the larger porosity and micropore volume in coals, the greater matrix compressibility. The coals Ro,max <1.0%, which have a loose chemical structure and high micropore volume, can bear a greater intrusion pressure than the coals with Ro,max &gt; >1.0%, in which the micropore structure will be broken when pressure exceeds 150?MPa. The coals with greater fractal dimension are more sensitive to stress. The matrix compression can lead to reduction of micropore volume and can make the micropore structure more irregular. It indicates that the increasing of effective stress with gas discharge could reduce the permeability of the reservoir and enhance the adsorption of micropore.Shao, X., Pang, X., Li, H., Hu, T., Xu, T., Xu, Y., Li, B., 2018. Pore network characteristics of lacustrine shales in the Dongpu Depression, Bohai Bay Basin, China, with implications for oil retention. Marine and Petroleum Geology 96, 457-473. development and the location of retained hydrocarbons are key topics to understand the shale oil system. In an attempt to investigate pore network characteristics and oil retention in lacustrine shales, 24 samples from the Es3 shales in the Dongpu Depression, Bohai Bay Basin were subjected to mineralogical, petrological, geochemistry and pore structure investigations using X-ray diffraction (XRD), thin section, field emission-scanning electronic microscope (FE-SEM), N2 adsorption-desorption. After removing retained oil by solvent extraction, 12 selected samples were again analyzed by Rock-Eval pyrolysis and N2 adsorption-desorption experiment. According to the mineral compositions and petrological characteristics, six types of lithofacies are identified in the Es3 shales in the Dongpu Depression: laminated calcareous shales, lenticular calcareous shales, laminated argillaceous shales, massive argillaceous shales, laminated siliceous shales, and massive siliceous shales. Geochemical characteristics of these shales are quite different, as calcareous/laminated shales have higher TOC contents than massive argillaceous and siliceous shales. Interparticle pores, intraparticle pores, organic matter pores and fracture pores are observed in the studied samples, while bitumens were found retaining in well-connected pore network. The N2 adsorption-desorption experiments on samples before and after solvent extraction reveal the different pore structure characteristics in six lithofacies and the occurrence of oil in lacustrine shales. In general, pore volumes within pore diameter range of 1.7–10 nm and 10–200 nm of samples show increase after solvent extraction, indicating that large and small pores in shales both play important roles in oil retention. Oil retained in shales can be divided as free and heavy fractions, as from the pyrolysis results. In lacustrine shales, larger pores are main storage space for hydrocarbon. Larger pores in different lithologies have similar capacity for free oil retention, while those in calcareous and argillaceous shales are more efficient for heavy oil retention. For both free and heavy oil, small pores in argillaceous shales are efficient for their storage.Shelley, J.T., Badal, S.P., Engelhard, C., Hayen, H., 2018. Ambient desorption/ionization mass spectrometry: evolution from rapid qualitative screening to accurate quantification tool. Analytical and Bioanalytical Chemistry 410, 4061-4076. this article, some recent trends and developments in ambient desorption/ionization mass spectrometry (ADI-MS) are reviewed, with a special focus on quantitative analyses with direct, open-air sampling. Accurate quantification with ADI-MS is still not routinely performed, but this aspect is considered of utmost importance for the advancement of the field. In fact, several research groups are devoted to the development of novel and optimized ADI-MS approaches. Some key trends include novel sample introduction strategies for improved reproducibility, tailored sample preparation protocols for removing the matrix and matrix effects, and multimode ionization sources. In addition, there is significant interest in quantitative mass spectrometry imaging.Shen, W., Zheng, L., Oldenburg, C.M., Cihan, A., Wan, J., Tokunaga, T.K., 2018. Methane diffusion and adsorption in shale rocks: A numerical study using the dusty gas model in TOUGH2/EOS7C-ECBM. Transport in Porous Media 123, 521-531. production from shale gas reservoirs plays a significant role in satisfying increasing energy demands. Compared with conventional sandstone and carbonate reservoirs, shale gas reservoirs are characterized by extremely low porosity, ultra-low permeability and high clay content. Slip flow, diffusion, adsorption and desorption are the primary gas transport processes in shale matrix, while Darcy flow is restricted to fractures. Understanding methane diffusion and adsorption, and gas flow and equilibrium in the low-permeability matrix of shale is crucial for shale formation evaluation and for predicting gas production. Modeling of diffusion in low-permeability shale rocks requires use of the Dusty gas model (DGM) rather than Fick’s law. The DGM is incorporated in the TOUGH2 module EOS7C-ECBM, a modified version of EOS7C that simulates multicomponent gas mixture transport in porous media. Also included in EOS7C-ECBM is the extended Langmuir model for adsorption and desorption of gases. In this study, a column shale model was constructed to simulate methane diffusion and adsorption through shale rocks. The process of binary CH4-N2 diffusion and adsorption was analyzed. A sensitivity study was performed to investigate the effects of pressure, temperature and permeability on diffusion and adsorption in shale rocks. The results show that methane gas diffusion and adsorption in shale is a slow process of dynamic equilibrium, which can be illustrated by the slope of a curve in CH4 mass variation. The amount of adsorption increases with the pressure increase at the low pressure, and the mass change by gas diffusion will decrease due to the decrease in the compressibility factor of the gas. With the elevated temperature, the gas molecules move faster and then the greater gas diffusion rates make the process duration shorter. The gas diffusion rate decreases with the permeability decrease, and there is a limit of gas diffusion if the permeability is less than 1.0 × 10 - 15 m 2 . The results can provide insights for a better understanding of methane diffusion and adsorption in the shale rocks so as to optimize gas production performance of shale gas reservoirs.Shi, F., Liu, H., Rodrigues, S., Esterle, J., Nguyen, A.K., Manlapig, E., 2018. Lithotype-based modelling and simulations of coal degradation conditioned by both high and low energy breakage. Fuel 232, 405-414. control of coal fragmentation and fines generation during mining and processing is important in coal production. A method to characterise, model and simulate coal size degradation and fines generation based on lithotypes has been developed. This method was refined to cover both high energy single impact to mimic blasting and crushing and low energy incremental breakage to mimic coal handling, transiting, stockpiling and processing. The JKRBT was utilised to characterise high energy single impact breakage and drop shatter tests were used to characterise low energy incremental breakage. X-ray Computed Tomography (XCT) scanning was used as an undisruptive technique to estimate size distributions of drill cores in the drop shatter tests. The JK size-dependent breakage model was applied for breakage characterisation, size degradation modelling and fines generation simulation. The results indicate that coal lithotype has a significant influence on coal degradation and fines generation. This paper has demonstrated that the adaption of two distinct breakage characterisation tests and linkage via the one model is a significant advance in quantifying coal degradation and fines generation during coal production.Shi, J., Chang, Y., Wu, S., Xiong, X., Liu, C., Feng, K., 2018. Development of material balance equations for coalbed methane reservoirs considering dewatering process, gas solubility, pore compressibility and matrix shrinkage. International Journal of Coal Geology 195, 200-216. one of the important unconventional resources, coalbed methane (CBM) can mitigate energy shortage issue, and its efficient exploitation has received widespread attention globally. The development of CBM is of great significance to coal mine safety and energy supply. CBM reserve evaluation provides a basis for selecting development zones and determining development strategies. However, most existing CBM reserve evaluation methods do not consider the effects of dissolved gas, free gas and the difference between initial reservoir pressure and critical desorption pressure. Thus, the predicted results usually deviate from the actual reserve.In this paper, firstly, the material balance equation (MBE) for early dewatering stage considering the effect of stress sensitivity on porosity is established, and the initial free gas and dissolved gas reserves of undersaturated CBM reservoirs can be obtained. Secondly, the MBE for gas desorption stage is derived, in which the effects of stress sensitivity, matrix shrinkage and dissolved gas are considered. So the original gas in place (OGIP) of CBM reservoirs can be solved. Next, the correctness and rationality of MBEs for early dewatering stage and gas desorption stage are verified against King's MBE method and CBM dynamic analysis software. Finally, this method is applied to actual production wells.The results show that in early dewatering stage, equations, have a linear shape, and the control area of CBM reservoir can be calculated based on the slope of the straight line. In addition, the ratio of the intercept to the slope of the straight line can be used to calculate the initial free gas and dissolved gas reserves of undersaturated CBM reservoirs. During gas desorption stage, p/Z* and Gp have a linear relationship. OGIP of CBM reservoirs can be obtained by the ratio of y-intercept to the slope of the straight line. Using gas and water production data provided by CBM dynamic analysis software, the reserves of undersaturated CBM reservoirs evaluated by the proposed method are in good agreement with those from CBM dynamic analysis software, which proves that the proposed material balance equations and corresponding methods are reasonable and reliable.The material balance equations and methods presented in this paper take into account the effects of various factors such as the difference between initial reservoir pressure and critical desorption pressure, pore compressibility, water compressibility, coal matrix shrinkage, dissolved gas, and free gas. The proposed reserve calculation methods for undersaturated CBM reservoirs can provide an important basis for selecting dominant production area, determining well spacing and guiding development policy.Shiao, J.C., Shirai, K., Tanaka, K., Takahata, N., Sano, Y., Hsiao, S.S.Y., Lee, D.C., Tseng, Y.C., 2018. Assimilation of nitrogen and carbon isotopes from fish diets to otoliths as measured by nanoscale secondary ion mass spectrometry. Rapid Communications in Mass Spectrometry 32, 1250-1256.; Nitrogen and carbon stable isotope ratios (δ15N and δ13C values) of carbonate‐bound organic materials in otoliths can provide information to address the biological and ecological functions of fish. Correct interpretation of otolith δ15N and δ13C profiles requires knowledge of the metabolic routes of nitrogen and carbon isotopes. However, the isotopic assimilation of δ15N and δ13C compositions from diets to otoliths has rarely been investigated. Methods: This study traced the daily nitrogen and carbon isotopic assimilation between diets and otoliths using nanoscale secondary ion mass spectrometry (NanoSIMS). Isotopically labeled algae (Tetraselmis chui) were fed to tilapia (Oreochromis niloticus) for 14–17 days. NanoSIMS and conventional isotope ratio mass spectrometry were used to measure δ15N and δ13C variations in the otoliths and fish muscle, respectively. Results: Otolith δ15N values abruptly surged from natural abundance levels by 1000–2300‰ after the fish ate 15N‐spiked algae with δ15N values of approximately 2200‰. However, the δ15N values of fish muscle increased to only approximately 500‰ at the end of the feeding experiment. Much higher δ15N values (3700–14 000‰) and moderate δ13C values (60–200‰) were detected in the otoliths after the tilapia ate 15N‐ and 13C‐spiked algae with a δ15N value of 36667‰ and a δ13C value of 272‰. Mapping analysis showed sub‐micrometer‐scale distribution of 15N embedded in the otolith growth increments with a low‐to‐high δ15N signal after the tilapia shifted diets from non‐spiked to 15N‐labeled algae. Conclusions: These results suggest that otolith nitrogen and carbon isotopes from food were directly assimilated on the same day. Food is the major and in some cases only source of otolith nitrogen isotopes but makes only a partial contribution to otolith carbon isotopes. Therefore, the δ15N values recorded in the sclerochronological layers of the otoliths can be used to determine the trophic levels, food sources and diet changes of fish. Shilla, D.J., Routh, J., 2018. Distribution, behavior, and sources of polycyclic aromatic hydrocarbon in the water column, sediments and biota of the Rufiji estuary, Tanzania. Frontiers in Earth Science 6, 70. doi: 10.3389/feart.2018.00070. establish the environmental status of Rufiji coastal waters in Tanzania, it is necessary to document the different contaminants as major entry points into the lower estuarine areas. Because there is no data on polycyclic aromatic hydrocarbon (PAH) contamination in this estuarine delta, the current study measured the concentrations of 19 PAHs in suspended particulate matter (SPM), surface sediments and marine organisms that are part of a telescoping food chain (gastropod Terebralia sp., clams Crassostrea cucullata, crabs Uca sp., panaeid shrimps Panaeus monodon, teleost Hilsa kelee, Trichiurus lepturus, and Arius thalassinus). Total PAH concentrations in SPM were low to moderate (18.7–223 ng/g) and varied between the sites; phenanthrene and chrysene were the dominant PAHs (2.40–47.2 and 4.20–28.1 ng/g, respectively). Significant variation between the sites indicates the in?uence of fuel spills and contribution from terrestrial sources resulting from different land use practices, such as agriculture, fishing, and harvesting firewood, charcoal, and mangroves poles. PAH concentrations in surface sediments were higher (127–376 ng/g) than SPM samples, and high molecular weight PAHs were the dominant fraction. Animal tissues indicated low PAH levels (9.20–158 ng/g). Only low molecular weight PAHs were dominant in the muscle tissues of pelagic and filter feeders (C. cucullata, P. monodon, and H. kelee). Bioaccumulation factor (BAF) ranged between 0.20 and 69.5 and it suggests 1) PAH accumulation in the marine organisms has so far been limited, and 2) distribution of PAHs in the Rufiji estuary poses limited risks.Shirodkar, G., Naqvi, S.W.A., Naik, H., Pratihary, A.K., Kurian, S., Shenoy, D.M., 2018. Methane dynamics in the shelf waters of the West coast of India during seasonal anoxia. Marine Chemistry 203, 55-63. Western Continental Shelf of India experiences water-column anoxia during late summer/early autumn, thereby providing conducive conditions for methane (CH4) accumulation. Measurements of CH4 along with other ancillary physico-chemical variables were made during the period of anoxia (September–October) in 2003, 2005 and 2009. The shelf waters experienced variable oxygen deficiency (hypoxic to anoxic) in space and time. Maximum observed accumulation of CH4 was only ~104?nmol/L although the bottom waters were strongly reducing with hydrogen sulphide (H2S) concentration reaching up to 26.6?μmol/L. Methane showed a reasonable positive correlation with H2S. The observed CH4 accumulation over the Indian shelf was lower than previously reported from the major Eastern Boundary Upwelling systems, especially off Namibia. It is proposed that the low organic loading arising from lower productivity and consequently weak sedimentary methanogenesis may largely account for the lower CH4 concentrations in anoxic bottom waters over the Indian shelf. Also, while anoxia may limit CH4 oxidation, sedimentary inputs are probably a more important source of water column CH4. In spite of the moderate CH4 build up in bottom waters, CH4 saturation at the sea-surface observed in the present study (89–1041%) was relatively lower than observed in 1996–1997 (~110–2521%). The sea to air flux of CH4 ranged from ?0.52 to 26.56?μmol?m?2?d?1, marginally higher than previously reported from the upwelling system in the western Arabian Sea.Shu, D., Zhang, B., He, Y., Wei, G., 2018. Abundant and rare microbial sub-communities in anammox granules present contrasting assemblage patterns and metabolic functions in response to inorganic carbon stresses. Bioresource Technology 265, 299-309. microorganisms play pivotal roles for the microbial nitrogen-cycling network in the anammox granular system. However, little is known about the effects of inorganic carbon (IC) stresses on the assemblage patterns and functional profiles of abundant and rare taxa. Herein, the community assemblage and functional traits of abundant and rare sub-communities were investigated. Results revealed that insufficient IC had adverse influences on the process performance, while anammox activity could be recovered by IC addition. Co-occurrence network analysis indicated that abundant and rare sub-communities present divergent co-occurrence patterns. Additionally, environmental filtering had different influences on the ecological adaptability of bacterial sub-communities. Furthermore, qPCR results illustrated that NH4+-N and NO2?-N consumption were regulated by abundant sub-community, while their accumulation was mediated by rare sub-community. Collectively, these findings suggest that abundant and rare sub-communities present contrasting assemblage patterns and metabolic pathways, and functional profiles dominated selection of bacterial sub-communities under IC stresses.Shukla, S.K., Pandey, S., Pandey, S., 2018. Applications of ionic liquids in biphasic separation: Aqueous biphasic systems and liquid–liquid equilibria. Journal of Chromatography A 1559, 44-61. liquids (ILs) have been receiving much attention in many fields of analytical chemistry because of their various interesting properties which distinguish them from volatile organic compounds. They offer both directional and non-directional forces towards a solute molecule and therefore act as excellent solvents for a wide range of polar and non-polar compounds. Because of the presence of various possible interactions, ILs easily undergo biphasic separation with water and other less polar/non-polar organic solvents. Their ability to create biphasic splitting makes them a promising candidate for liquid–liquid separation processes, such as aqueous biphasic systems and liquid–liquid equilibria. Various aspects of ILs in these separation methods are discussed in view of the origin of physical forces responsible for the biphasic interactions, the effect of structural components, temperature, pressure, pH and additives. The specific advantages of using ILs in aqueous biphasic systems and liquid–liquid equilibria in binary and ternary systems are discussed with a view to defining their future role in separation processes by giving major emphasis on developing non-toxic ILs with physical and solution properties tailored to the needs of specific sample preparation techniques.Signori, C.N., Pellizari, V.H., Enrich-Prast, A., Sievert, S.M., 2018. Spatiotemporal dynamics of marine bacterial and archaeal communities in surface waters off the northern Antarctic Peninsula. Deep Sea Research Part II: Topical Studies in Oceanography 149, 150-160. changes in taxonomic and functional diversity of microbial communities in polar regions are commonly observed, requiring strategies of microbes to adapt to the corresponding changes in environmental conditions. These natural fluctuations form the backdrop for changes induced by anthropogenic impacts. The main goal of this study was to assess the seasonal and temporal changes in bacterial and archaeal diversity and community structure off the northern Antarctic Peninsula over several seasons (spring, summer, autumn) from 2013 to 2015. Ten monitoring stations were selected across the Gerlache and Bransfield Straits and nearby Elephant Island, and archaeal and bacterial communities examined by amplicon sequencing of 16S rRNA genes. Alpha-diversity indices were higher in spring and correlated significantly with temperature. Spring was characterized by the presence of SAR11, and microbial communities remaining from winter, including representatives of Thaumarchaeota (Nitrosopumilus), Euryarchaeota, members of Oceanospirillales, SAR324. Summer and autumn were characterized by a high prevalence of Flavobacteria (NS5 marine group and Polaribacter), Alphaproteobacteria (Rhodobacterales and SAR11 clade) and Gammaproteobacteria (Oceanospirillales/Balneatrix and Cellvibrionales), generally known to be associated with organic matter degradation. Relatively higher abundance of phytoplankton groups occurred in spring, mainly characterized by the presence of the haptophyte Phaeocystis and the diatom Corethron, influencing the succession of heterotrophic bacterial communities. Microbial diversity and community structure varied significantly over time, but not over space, i.e., were similar between monitoring stations for the same time. In addition, the observed interannual variability in microbial community structure might be related to an increase in sea surface temperature. Environmental conditions related to seasonal variation, including temperature and most likely phytoplankton derived organic matter, appear to have triggered the observed shifts in microbial communities in the waters off the northern Antarctic Peninsula.Sim?es, T.R., Caldwell, M.W., Ta?anda, M., Bernardi, M., Palci, A., Vernygora, O., Bernardini, F., Mancini, L., Nydam, R.L., 2018. The origin of squamates revealed by a Middle Triassic lizard from the Italian Alps. Nature 557, 706-709. squamates (lizards, snakes and amphisbaenians) are the world’s most diverse group of tetrapods along with birds and have a long evolutionary history, with the oldest known fossils dating from the Middle Jurassic period—168 million years ago. The evolutionary origin of squamates is contentious because of several issues: (1) a fossil gap of approximately 70 million years exists between the oldest known fossils and their estimated origin; (2) limited sampling of squamates in reptile phylogenies; and (3) conflicts between morphological and molecular hypotheses regarding the origin of crown squamates. Here we shed light on these problems by using high-resolution microfocus X-ray computed tomography data from the articulated fossil reptile Megachirella wachtleri (Middle Triassic period, Italian Alps). We also present a phylogenetic dataset, combining fossils and extant taxa, and morphological and molecular data. We analysed this dataset under different optimality criteria to assess diapsid reptile relationships and the origins of squamates. Our results re-shape the diapsid phylogeny and present evidence that M. wachtleri is the oldest known stem squamate. Megachirella is 75 million years older than the previously known oldest squamate fossils, partially filling the fossil gap in the origin of lizards, and indicates a more gradual acquisition of squamatan features in diapsid evolution than previously thought. For the first time, to our knowledge, morphological and molecular data are in agreement regarding early squamate evolution, with geckoes—and not iguanians—as the earliest crown clade squamates. Divergence time estimates using relaxed combined morphological and molecular clocks show that lepidosaurs and most other diapsids originated before the Permian/Triassic extinction event, indicating that the Triassic was a period of radiation, not origin, for several diapsid lineages.Singh, A.K., Kumar, A., Singh, P.K., Singh, A.L., Kumar, A., 2018. Bacterial desulphurization of low-rank coal: A case study of Eocene Lignite of Western Rajasthan, India. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 40, 1199-1208. sulfur lignite samples collected from Giral mine was subjected to desulfurization using bacteria Burkholderia sp. GR 8–02 isolated from native lignite. A removal of 50.69% of total Sulfur (St) has been observed. The reduction in hydrogen and ash content was found up to 2.92% and 14.78%, respectively. In addition, relative carbon (up to 12.81%) and nitrogen (up to 34.52%) has also been increased. An increase in the relative concentration of volatile matter and fixed carbon (up to 19.47% & 3.29%) has been detected. In addition, the desulfurization of high sulfur lignite with Burkholderia sp. GR 8–02 increased the calorific value from 5.24% to 20.74%.Smith, H.J., Dieser, M., McKnight, D.M., SanClements, M.D., Foreman, C.M., 2018. Relationship between dissolved organic matter quality and microbial community composition across polar glacial environments. FEMS Microbiology Ecology 94, Article fiy090. expanses of Earth’s surface are covered by ice, with microorganisms in these systems affecting local and global biogeochemical cycles. We examined microbial assemblages from habitats fed by glacial meltwater within the McMurdo Dry Valleys, Antarctica and on the west Greenland Ice Sheet (GrIS), evaluating potential physicochemical factors explaining trends in community structure. Microbial assemblages present in the different Antarctic dry valley habitats were dominated by Sphingobacteria andFlavobacteria, while Gammaproteobacteria and Sphingobacteria prevailed in west GrIS supraglacial environments. Microbial assemblages clustered by location (Canada Glacier, Cotton Glacier and west GrIS) and were separated by habitat type (i.e. ice, cryoconite holes, supraglacial lakes, sediment and stream water). Community dissimilarities were strongly correlated with dissolved organic matter (DOM) quality. Microbial meltwater assemblages were most closely associated with different protein-like components of the DOM pool. Microbes in environments with mineral particles (i.e. stream sediments and cryoconite holes) were linked to DOM containing more humic-like fluorescence. Our results demonstrate the establishment of distinct microbial communities within ephemeral glacial meltwater habitats, with DOM-microbe interactions playing an integral role in shaping communities on local and polar spatial scales.Smith, N.M., Ebrahimi, H., Ghosh, R., Dickerson, A.K., 2018. High-speed microjets issue from bursting oil gland reservoirs of citrus fruit. Proceedings of the National Academy of Sciences 115, E5887-E5895.. Here we show a unique, natural method for microscale jetting of fluid made possible by the tuning of material properties from which the jets emanate. The composite, layered construction of the citrus exocarp allows for the buildup of fluid pressure in citrus oil gland reservoirs and their subsequent explosive rupture. Citrus jetting has not been documented in literature, and its purpose is unknown. This method for microscale fluid dispersal requires no auxiliary equipment and may open avenues for new methods of medicine and chemical delivery. We show how jet kinematics are related to substrate properties and reservoir shape.Abstract. The rupture of oil gland reservoirs housed near the outer surface of the citrus exocarp is a common experience to the discerning citrus consumer and bartenders the world over. These reservoirs often rupture outwardly in response to bending the peel, which compresses the soft material surrounding the reservoirs, the albedo, increasing fluid pressure in the reservoir. Ultimately, fluid pressure exceeds the failure strength of the outermost membrane, the flavedo. The ensuing high-velocity discharge of oil and exhaustive emptying of oil gland reservoirs creates a method for jetting small quantities of the aromatic oil. We compare this jetting behavior across five citrus hybrids through high-speed videography. The jetting oil undergoes an extreme acceleration to reach velocities in excess of 10 m/s. Through material characterization and finite element simulations, we rationalize the combination of tuned material properties and geometries enabling the internal reservoir pressures that produce explosive dispersal, finding the composite structure of the citrus peel is critical for microjet production.Sobolev, I.S., Bredikhin, N.P., Bratec, T., Falk, A.Y., Tolkachev, O.S., Rikhvanov, L.P., Tishin, P.A., 2018. Chemical diagenesis in near-surface zone above oil fields in geochemical exploration. Applied Geochemistry 95, 33-44. microseepages result in chemical and mineralogical changes in the near-surface zone above oil reservoirs. The results of geochemical research within the three oil fields of the West Siberian Basin demonstrate that chemical diagenetic processes lead to an increased inhomogeneity in chemical element distribution in soils, subsoil atmosphere and snow. Pulse cathodoluminescence (PCL) study of soils and transmission electron microscopy (TEM) study of micro- and nanoparticles, collected from the subsoil atmosphere, showed that geochemical conditions over oil reservoirs were favorable for the enrichment of silicate and aluminosilicate minerals by chemical impurities. Chemical composition of micro- and nanoparticles of metal compounds, collected from within the vertical projection of the oil field outline, suggested that these compounds were formed under intense reductive conditions that are not characteristic for the hypergene zone.Song, Y., Liu, S., Ma, X., Ju, Y., Hong, F., Jiang, L., 2018. Accumulation models for coalbed methane in medium- to high-rank coals: examples from the southern Qinshui Basin and southeastern Ordos Basin. Australian Journal of Earth Sciences 65, 575-590. majority of known coalbed methane (CBM) production worldwide comes primarily from high-abundance CBM-enrichment areas or ‘fairways.’ The high-abundance CBM-enrichment areas are primarily characterised by large CBM resources with high single-well productions. CBM accumulation areas from the medium- to high-rank coals in the southern Qinshui Basin and the Hancheng CBM fields in the Ordos Basin were investigated based on regional geological analyses and physical analogue experiments. The results show that gas contents in the study areas increase with depths over the range from approximately 300 to 800 m, while permeabilities generally decrease with depths. Intervals with optimal gas content and permeability exist at a moderate depth along an inclined coal seam under the coupled control of temperature and stress. Brittle–ductile transition deformation increases the permeability and the pore-specific surface areas of coals. The gas content and permeability of the CBM reservoirs are shown to be two key factors determining the formation of high-abundance CBM areas. The coupling of gas enrichment and high permeability provides a favourable combination for CBM accumulation and high production. Combining CBM exploration and development practices in the study areas with physical analogue experiments, two CBM-enrichment models for medium- to high-rank coal have been recognised for different geological conditions, including (1) the model controlled by the depth in the slope zone and (2) the model controlled by the coal brittle and ductile in the deformation zones.Spyrou, M.A., Tukhbatova, R.I., Wang, C.-C., Valtue?a, A.A., Lankapalli, A.K., Kondrashin, V.V., Tsybin, V.A., Khokhlov, A., Kühnert, D., Herbig, A., Bos, K.I., Krause, J., 2018. Analysis of 3800-year-old Yersinia pestis genomes suggests Bronze Age origin for bubonic plague. Nature Communications 9, Article 2234. origin of Yersinia pestis and the early stages of its evolution are fundamental subjects of investigation given its high virulence and mortality that resulted from past pandemics. Although the earliest evidence of Y. pestis infections in humans has been identified in Late Neolithic/Bronze Age Eurasia (LNBA 5000–3500y BP), these strains lack key genetic components required for flea adaptation, thus making their mode of transmission and disease presentation in humans unclear. Here, we reconstruct ancient Y. pestis genomes from individuals associated with the Late Bronze Age period (~3800 BP) in the Samara region of modern-day Russia. We show clear distinctions between our new strains and the LNBA lineage, and suggest that the full ability for flea-mediated transmission causing bubonic plague evolved more than 1000 years earlier than previously suggested. Finally, we propose that several Y. pestis lineages were established during the Bronze Age, some of which persist to the present day.Steele, E.J., Al-Mufti, S., Augustyn, K.A., Chandrajith, R., Coghlan, J.P., Coulson, S.G., Ghosh, S., Gillman, M., Gorczynski, R.M., Klyce, B., Louis, G., Mahanama, K., Oliver, K.R., Padron, J., Qu, J., Schuster, J.A., Smith, W.E., Snyder, D.P., Steele, J.A., Stewart, B.J., Temple, R., Tokoro, G., Tout, C.A., Unzicker, A., Wainwright, M., Wallis, J., Wallis, D.H., Wallis, M.K., Wetherall, J., Wickramasinghe, D.T., Wickramasinghe, J.T., Wickramasinghe, N.C., Liu, Y., 2018. Cause of Cambrian Explosion - Terrestrial or Cosmic? Progress in Biophysics and Molecular Biology 136, 3-23. review the salient evidence consistent with or predicted by the Hoyle-Wickramasinghe (H-W) thesis of Cometary (Cosmic) Biology. Much of this physical and biological evidence is multifactorial. One particular focus are the recent studies which date the emergence of the complex retroviruses of vertebrate lines at or just before the Cambrian Explosion of ～500 Ma. Such viruses are known to be plausibly associated with major evolutionary genomic processes. We believe this coincidence is not fortuitous but is consistent with a key prediction of H-W theory whereby major extinction-diversification evolutionary boundaries coincide with virus-bearing cometary-bolide bombardment events. A second focus is the remarkable evolution of intelligent complexity (Cephalopods) culminating in the emergence of the Octopus. A third focus concerns the micro-organism fossil evidence contained within meteorites as well as the detection in the upper atmosphere of apparent incoming life-bearing particles from space. In our view the totality of the multifactorial data and critical analyses assembled by Fred Hoyle, Chandra Wickramasinghe and their many colleagues since the 1960s leads to a very plausible conclusion – life may have been seeded here on Earth by life-bearing comets as soon as conditions on Earth allowed it to flourish (about or just before 4.1 Billion years ago); and living organisms such as space-resistant and space-hardy bacteria, viruses, more complex eukaryotic cells, fertilised ova and seeds have been continuously delivered ever since to Earth so being one important driver of further terrestrial evolution which has resulted in considerable genetic diversity and which has led to the emergence of mankind.Steele, E.J., Al-Mufti, S., Augustyn, K.A., Chandrajith, R., Coghlan, J.P., Coulson, S.G., Ghosh, S., Gillman, M., Gorczynski, R.M., Klyce, B., Louis, G., Mahanama, K., Oliver, K.R., Padron, J., Qu, J., Schuster, J.A., Smith, W.E., Snyder, D.P., Steele, J.A., Stewart, B.J., Temple, R., Tokoro, G., Tout, C.A., Unzicker, A., Wainwright, M., Wallis, J., Wallis, D.H., Wallis, M.K., Wetherall, J., Wickramasinghe, D.T., Wickramasinghe, J.T., Wickramasinghe, N.C., Liu, Y., 2018. Reply to editorial and commentaries on Steele, Al-Mufti, Augustyn, Chandrajith, Coghlan, Coulson et al. (2018) "Cause of Cambrian explosion - Terrestrial or cosmic?". Progress in Biophysics and Molecular Biology 136, 27-28. an individual scientist a paradigm shift occurs in two stages: 1). An instant personal decision to embrace the new global way of understanding reality. This happens within a blink of an eye, as in a Gestalt shift made famous by Thomas Kuhn. The individual confronting the data compares the available evidence for and against - a piece of evidence clicks into place which only makes sense under the new alternative paradigm, and is quite nonsensical under the old way of understanding the world.2). This personal decision can then move into the public domain but there are many inhibitory processes as the scholar and scientist has to weigh up the socio-political costs, such as: How will this affect my relationships with colleagues? How will this affect my prospects for promotion? How will this affect my future prospects for research funding? etc.The more fundamental the shift the deeper is the problem for successfully moving to stage 2. However these shifts do happen regularly in Science and are largely accrued community decisions over time (See <;.). It is an intellectual battle as described in that Wiki article: When enough significant anomalies have accrued against a current paradigm, the scientific discipline is thrown into a state of crisis, according to Kuhn. During this crisis, new ideas, perhaps ones previously discarded, are tried. Eventually a new paradigm is formed, which gains its own new followers, and an intellectual "battle" takes place between the followers of the new paradigm and the hold-outs of the old paradigm.The battle between rival paradigms on the origin and further evolution of life on Earth is underway and we look forward to more scientists engaging in it. The battle should enrich and spur on each paradigm. However we agree that the thesis that life is a cosmic phenomenon is generally considered inadmissible by the body politic of scientists today. The intellectual shift in the population of scientists to the cosmic perspective will, of course, be protracted particularly in the messy final stages - for example as occurred in the first Copernican revolution - which are likely to continue for some time. Thus to directly quote Kuhn: …The state of Ptolemaic (Earth-centred) astronomy was a scandal before Copernicus' announcement. Given a particular discrepancy, astronomers were invariably able to eliminate it by making some particular adjustment in Ptolemy's system of compounded circles. But as time went on, a man looking at the net result of the normal research effort of many astronomers could observe that astronomy's complexity was increasing far more rapidly than its accuracy and that a discrepancy corrected in one place was likely to show up in another (Kuhn, 1969).We have therefore resisted the temptation to respond in detail to the interesting Commentaries by Keith Baverstock (2018) and Karin Moelling (2018). We agree with the Editor Denis Noble (2018) that the whole issue is on the verge of being decided by decisive evidence of extra-terrestrial life being found elsewhere in our solar system, particularly in the water rich warmed interiors of comets and moons (and their snap frozen ejecta). We have laid out all the key data, analyses and critical arguments why we believe there is already wide ranging supportive evidence collected over the past 50 years by Fred Hoyle, Chandra Wickramasinghe and their associates, many of whom are co-authors of this review. We urge those interested to read our article, then read the key books and papers cited in the primary literature. On this we rest our case but we are of course open to further email discussions. As the Editor has done we also thank the authors of the Commentaries for sharing their arguments in print, and the four anonymous referees for their careful work.ReferencesKeith Baverstock (2018) Commentary to: "Cause of Cambrian Explosion - Terrestrial or Cosmic? Steele, E.J. et al" to accompany the article by Steele, et al in Progress in Biophysics and Molecular BiologyThomas S. Kuhn: The Structure of Scientific Revolutions (1969) p.68 Second Enlarged Edition, University of Chicago Press, ChicagoKarin Moelling (2018) Commentary to: " Cause of Cambrian Explosion - Terrestrial or Cosmic? Steele, E.J. et al " to accompany the article by Steele, et al in Progress in Biophysics and Molecular BiologyNoble (2018) Editorial to: " Cause of Cambrian Explosion - Terrestrial or Cosmic? Steele, E.J. et al " to accompany the article by Steele, et al in Progress in Biophysics and Molecular BiologyStewart, L.C., Stucker, V.K., Stott, M.B., de Ronde, C.E.J., 2018. Marine-influenced microbial communities inhabit terrestrial hot springs on a remote island volcano. Extremophiles 22, 687-698. Island is a subaerial island volcano approximately 1000?km northeast of New Zealand. Its caldera contains a circumneutral closed-basin volcanic lake and several associated pools, as well as intertidal coastal hot springs, all fed by a hydrothermal system sourced from both meteoric water and seawater. Here, we report on the geochemistry, prokaryotic community diversity, and cultivatable abundance of thermophilic microorganisms of four terrestrial features and one coastal feature on Raoul. Hydrothermal fluid contributions to the volcanic lake and pools make them brackish, and consequently support unusual microbial communities dominated by Planctomycetes, Chloroflexi, Alphaproteobacteria, and Thaumarchaeota, as well as up to 3% of the rare sister phylum to Cyanobacteria, Candidatus Melainabacteria. The dominant taxa are mesophilic to moderately thermophilic, phototrophic, and heterotrophic marine groups related to marine Planctomycetaceae. The coastal hot spring/shallow hydrothermal vent community is similar to other shallow systems in the Western Pacific Ocean, potentially due to proximity and similarities of geochemistry. Although rare in community sequence data, thermophilic methanogens, sulfur-reducers, and iron-reducers are present in culture-based assays.Stolpovsky, K., Dale, A.W., Wallmann, K., 2018. A new look at the multi-G model for organic carbon degradation in surface marine sediments for coupled benthic–pelagic simulations of the global ocean Biogeosciences 15, 3391-3407. kinetics of particulate organic carbon (POC) mineralization in marine surface sediments is not well constrained. This creates considerable uncertainties when benthic processes are considered in global biogeochemical or Earth system circulation models to simulate climate–ocean interactions and biogeochemical tracer distributions in the ocean. In an attempt to improve our understanding of the rate and depth distribution of organic carbon mineralization in bioturbated (0–20?cm) sediments at the global scale, we parameterized a 1-D diagenetic model that simulates the mineralization of three discrete POC pools (a multi-G model). The rate constants of the three reactive classes (highly reactive, reactive, refractory) are fixed and determined to be 70, 0.5 and ～?0.001?yr?1, respectively, based on the Martin curve model for pelagic POC degradation. In contrast to previous approaches, however, the reactivity of the organic material degraded in the seafloor is continuous with, and set by, the apparent reactivity of material sinking through the water column. Despite the simplifications of describing POC remineralization using G-type approaches, the model is able to simulate a global database (185 stations) of benthic oxygen and nitrate fluxes across the sediment–water interface in addition to porewater oxygen and nitrate distributions and organic carbon burial efficiencies. It is further consistent with degradation experiments using fresh phytoplankton reported in a previous study. We propose that an important yet mostly overlooked consideration in upscaling approaches is the proportion of the reactive POC classes reaching the seafloor in addition to their reactivity. The approach presented is applicable to both steady-state and non-steady state scenarios, and links POC degradation kinetics in sedimentary environments to water depth and the POC rain rate to the seafloor.St?tter, T., Bastviken, D., Bodelier, P.L.E., van Hardenbroek, M., Rinta, P., Schilder, J., Schubert, C.J., Heiri, O., 2018. Abundance and δ13C values of fatty acids in lacustrine surface sediments: Relationships with in-lake methane concentrations. Quaternary Science Reviews 191, 337-347. in lake sediments provide the only approach by which the dynamics of in-lake methane cycling can be examined on multi-decadal to centennial time scales. This information is necessary to constrain how lacustrine methane production, oxidation and emissions are expected to respond to global change drivers. Several of the available proxies for reconstructing methane cycle changes of lakes rely on interpreting past changes in the abundance or relevance of methane oxidizing bacteria (MOB), either directly (e.g. via analysis of bacterial lipids) or indirectly (e.g. via reconstructions of the past relevance of MOB in invertebrate diet). However, only limited information is available about the extent to which, at the ecosystem scale, variations in abundance and availability of MOB reflect past changes in in-lake methane concentrations. We present a study examining the abundances of fatty acids (FAs), particularly of 13C-depleted FAs known to be produced by MOB, relative to methane concentrations in 29 small European lakes. 39 surface sediment samples were obtained from these lakes and FA abundances were compared with methane concentrations measured at the lake surface, 10?cm above the sediments and 10?cm within the sediments. Three of the FAs in the surface sediment samples, C16:1ω7c, C16:1ω5c/t, and C18:1ω7c were characterized by lower δ13C values than the remaining FAs. We show that abundances of these FAs, relative to other short-chain FAs produced in lake ecosystems, are related with sedimentary MOB concentrations assessed by quantitative polymerase chain reaction (qPCR). We observed positive relationships between methane concentrations and relative abundances of C16:1ω7c, C16:1ω5c/t, and C18:1ω7c and the sum of these FAs. For the full dataset these relationships were relatively weak (Spearman's rank correlation (rs) of 0.34–0.43) and not significant if corrected for multiple testing. However, noticeably stronger and statistically significant relationships were observed when sediments from near-shore and deep-water oxic environments (rs?=?0.57 to 0.62) and those from anoxic deep-water environment (rs?=?0.55 to 0.65) were examined separately. Our results confirm that robust relationships exist between in-lake CH4 concentrations and 13C-depleted groups of FAs in the examined sediments, agreeing with earlier suggestions that the availability of MOB-derived, 13C-depleted organic matter for aquatic invertebrates increases with increasing methane concentrations. However, we also show that these relationships are complex, with different relationships observed for oxic and anoxic sediments and highest values measured in sediments deposited in oxic environments overlain with relatively methane-rich water. Furthermore, although all three 13C-depleted FA groups identified in our survey are known to be produced by MOB, they also receive contributions by other organism groups, and this will have influenced their distribution in our dataset.Stranghoener, M., Schippers, A., Dultz, S., Behrens, H., 2018. Experimental microbial alteration and Fe mobilization from basaltic rocks of the ICDP HSDP2 drill core, Hilo, Hawaii. Frontiers in Microbiology 9, 1252. doi: 1210.3389/fmicb.2018.01252. interaction of a single bacterial species (Burkholderia fungorum) with basaltic rocks from the ICDP HSDP2 drill core and synthetic basaltic glasses was investigated in batch laboratory experiments to better understand the role of microbial activity on rock alteration and Fe mobilization. Incubation experiments were performed with drill core basaltic rock samples to investigate differences in the solution chemistry during biotic and abiotic alteration. Additionally, colonization experiments with synthetic basaltic glasses of different Fe redox states and residual stresses were performed to evaluate their influence on microbial activity and surface attachment of cells. In biotic incubation experiments bacterial growth was observed and the release of Fe and other major elements from drill core basaltic rocks to solution exceeded that of abiotic controls only when the rock sample assay was nutrient depleted. The concentration of dissolved major elements in solution in biotic colonization experiments with synthetic basaltic glasses increased with increasing residual stress and Fe(II) content. Furthermore, the concentration of dissolved Fe and Al increased similarly in biotic colonization experiments indicating that their dissolution might be triggered by microbial activity. Surface morphology imaging by SEM revealed that cells on basaltic rocks in incubation experiments were most abundant on the glass and surfaces with high roughness and almost absent on minerals. In colonization experiments, basaltic glasses with residual stress and high Fe(II) content were intensely covered with a cellular biofilm. In contrast, glasses with high Fe(III) content and no residual stress were sparsely colonized. We therefore conclude that structurally bound Fe is most probably used by B. fungorum as a nutrient. Furthermore, we assume that microbial activity overall increased rock dissolution as soon as the environment becomes nutrient depleted. Our results show that besides compositional effects, other factors such as redox state and residual stress can control microbial alteration of basaltic glasses.Street-Perrott, F.A., Holmes, J.A., Robertson, I., Ficken, K.J., Koff, T., Loader, N.J., Marshall, J.D., Martma, T., 2018. The Holocene isotopic record of aquatic cellulose from Lake ?ntu Sinij?rv, Estonia: Influence of changing climate and organic-matter sources. Quaternary Science Reviews 193, 68-83. well characterized oxygen-isotopic fractionation during cellulose biosynthesis has been utilised by numerous studies of stable isotopes in fine-grained aquatic cellulose. We measured the δ13Ccellulose and δ18Ocellulose values of bulk cellulose and moss fragments from an ～11.4ka-long core obtained from a shallow, productive, spring-fed, hardwater lake, ?ntu Sinij?rv, Estonia (59?3.8′N; 26?14.5′E; 94.6?m a.s.l.; maximum depth 7.3?m), in order to reconstruct regional Holocene climate and lake-basin evolution. Isotopically, the modern waterbody is a well-behaved, open, hydrological system with negligible evaporative effects. Cellulose-isotope records were compared with down-core measurements of loss-on-ignition (LOI), carbonate and mineral contents, total organic carbon (TOC), total nitrogen (TN), C/N ratio, δ13CTOC, biomarker indices (Palg and Paq), published palaeoecological data and a δ18Ocarbonate record from the same palaeolake. Green microalgae, freshwater macroalgae (Chara) and aquatic bryophytes were important sources of sedimentary cellulose during different phases in the environmental history of the lake. Although a strong palaeoclimatic imprint can be detected in the δ18Ocellulose record from ?ntu Sinij?rv, notably the Preboreal oscillation, the 8.2ka event and an unnamed cold oscillation ～3.25ka BP, the isotopic signal of these events may have been amplified by increases in 18O-depleted spring snowmelt. In contrast, δ18Ocellulose was tightly coupled to the Holocene evolution of terrestrial ecosystems and soils by significant inputs of biogenic carbon from the catchment and sublacustrine springs. During the early Holocene, ～11 – 9ka BP, the δ18Ocellulose and δ18Ocarbonate records diverge markedly, which can be attributed to “no-analogue” seasonal, climatic, hydrological and isotopic conditions resulting from orbital forcing and residual ice-sheet impacts.Su, K., Lu, J., Zhang, G., Chen, S., Li, Y., Xiao, Z., Wang, P., Qiu, W., 2018. Origin of natural gas in Jurassic Da'anzhai Member in the western part of central Sichuan Basin, China. Journal of Petroleum Science and Engineering 167, 890-899. distribution pattern of oil and gas in the western part of central Sichuan Basin is complicated, there are many different views on the sources of natural gas, which restrict further exploration and deployment of oilfields. Therefore, by analyzing geochemical characteristics and quantitative calculation of natural gas in study area, combined with the data of structure and gas-oil ratio, the origin and sources of gas are discussed and analyzed. The results show that the dryness coefficient of the natural gas ranges between 0.71 ～ 0.93, δ13C values range between ?45.3 ～ ?38.0‰ in methane, ?32.0 ～ ?25.6‰ in ethane and ?30.0 ～ ?25.3‰ in propane. Crossplots of isotope data and quantitative calculation indicate that natural gas in Da'anzhai Member is characterized by the mixture of sapropelic and humic natural gas, the humic gas largely occupies the proportion of 20–40%, up to 70%. It is the result of upward migration of natural gas in Triassic Xujiahe Formation. The abnormally high gas-oil ratio is an important manifestation of this upward intrusion. Based on the study of high gas-oil ratio wells, the distribution of humic natural gas that intruded from Xujiahe Formation and enriched in Da'anzhai Member is unevenly distributed. It inherits characteristics of “Plaque accumulation” of natural gas in Xujiahe Formation. The inhomogeneity of this plane distribution is controlled by fault location, fault scale and the size of underlying Xujiahe Formation gas reservoirs. The humic gas from Xujiahe Formation occupies a large proportion in blocks of Da'anzhai Member which are favorable for intrusion, accumulation and preservation of Xujiahe Formation natural gas, whereas for blocks without these conditions, natural gas is often associated gas.Su, S., Jiang, Z., Shan, X., Zhu, Y., Wang, P., Luo, X., Li, Z., Zhu, R., Wang, X., 2018. The wettability of shale by NMR measurements and its controlling factors. Journal of Petroleum Science and Engineering 169, 309-316. this study, shale samples from the Zhanhua Sag in the Jiyang Depression of the Bohai Bay Basin were used to test the wettability of shale by nuclear magnetic resonance (NMR). The organic matter abundance, movable hydrocarbon content, clay content and carbonate content of shale samples with different wetting characteristics were compared. The results demonstrated that the TOC content of shale samples with mixed wettability was greater than that of water-wettability samples. This finding indicates that with the increase in TOC content, pores can be changed from water-wetting to oil-wetting, and the inorganic pores become organic. The above analysis demonstrates that the existence of organic matter is the basic reason that shale porosity exhibits oil wettability. Further, the shale samples with mixed wettability were higher in mobile hydrocarbon content (S1) than were those with only water wettability. The shale samples with mixed wettability showed higher clay content than did those with water wettability, indicating that organic matter is associated with clay minerals. However, the samples with water wettability had greater carbonate content than those with mixed wettability, indicating that inorganic pores are formed primarily by carbonate rock. In summary, shale with mixed wettability in the Zhanhua Sag can be used as an exploration target favorable for shale oil enrichment.Sun, F., Tian, W., Chen, Z., Sun, B., Yang, M., Sun, Q., Qi, L., Zhang, Y., Wu, B., 2018. Low-rank coalbed methane gas pooling in China: Characteristics and exploration orientation. Natural Gas Industry 38, 10-18. to the complicated geological settings of low-rank coal-bearing basins and particular CBM enrichment characteristics, CBM exploration has been in a test stage. In view of this, we first summarized coal-bearing basin types, CBM gas origins, occurrence states and accumulation modes, etc. On this basis, we analyzed the present challenges and further goals of scientific research and put forward the favorable exploration orientation for CBM gas reservoirs of low rank coals. The following findings were obtained. (1) The low-rank coalbed methane gas pooling is characterized by diversified basin types, various origins, multiple occurrence states, and accumulation modes. (2) The low-rank coalbed methane gas exploration is now challenged by optimal selection of exploration targets, evaluation of co-exploration and co-production system of deep-strata coal-derived gas, and reservoir stimulation technologies together with drilling & completion. (3) Further related research will focus on the CBM gas pooling process and dynamic mechanisms, gas origins and resource contribution, adsorptive and free CBM gas space distribution laws and geological controlling factors, and CBM gas resource availability and recoverability assessment should be made, thus a series of deep-strata coal-derived gas exploration and development evaluation methodologies will be developed. In conclusion, it is considered that favorable CBM gas exploration zones in shallow strata will include Jiergalangtu, Huolinhe, Baiyanhua depressions in the Erlian Basin Groups, Yimin, Huhehu, Chenqi depression in the Hailar Basin Groups, and Binxian, Jiaoping, Huangling, eastern Wushenqi in the Ordos Basin, and the southern margin areas in the Junggar Basin, while those zones in deep strata will include the areas in the Junggar, Tuha, Santanghu, Hailar and Sanjiang basins or basin groups.Sun, J.-Q., Xu, L., Liu, X.-Y., Zhao, G.-F., Cai, H., Nie, Y., Wu, X.-L., 2018. Functional genetic diversity and culturability of petroleum-degrading bacteria isolated from oil-contaminated soils. Frontiers in Microbiology 9, 1332. doi: 1310.3389/fmicb.2018.01332 this study, we compared the culturability of aerobic bacteria isolated from long-term oil-contaminated soils via enrichment and direct-plating methods; bacteria were cultured at 30°C or ambient temperatures. Two soil samples were collected from two sites in the Shengli oilfield located in Dongying, China. One sample (S0) was close to the outlet of an oil-production water treatment plant, and the other sample (S1) was located 500 m downstream of the outlet. In total, 595 bacterial isolates belonging to 56 genera were isolated, distributed in Actinobacteria, Firmicutes, Bacterioidetes, and Proteobacteria. It was interesting that Actinobacteria and Firmicutes were not detected from the 16S rRNA gene clone library. The results suggested the activation of rare species during culture. Using the enrichment method, 239 isolates (31 genera) and 96 (22 genera) isolates were obtained at ambient temperatures and 30°C, respectively, from S0 soil. Using the direct-plating method, 97 isolates (15 genera) and 163 isolates (20 genera) were obtained at ambient temperatures and 30°C, respectively, from two soils. Of the 595 isolates, 244 isolates (41.7% of total isolates) could degrade n-hexadecane. A greater number of alkane-degraders was isolated at ambient temperatures using the enrichment method, suggesting that this method could significantly improve bacterial culturability. Interestingly, the proportion of alkane degrading isolates was lower in the isolates obtained using enrichment method than that obtained using direct-plating methods. Considering the greater species diversity of isolates obtained via the enrichment method, this technique could be used to increase the diversity of the microbial consortia. Furthermore, phenol hydroxylase genes (pheN), medium-chain alkane monooxygenases genes (alkB and CYP153A), and long-chain alkane monooxygenase gene (almA) were detected in 60 isolates (11 genotypes), 91 isolates (27 genotypes) and 93 isolates (24 genotypes), and 34 isolates (14 genotypes), respectively. This study could provide new insights into microbial resources from oil fields or other environments, and this information will be beneficial for bioremediation of petroleum contamination and for other industrial applications.Sun, L., Chiu, M.-H., Xu, C., Lin, P., Schwehr, K.A., Bacosa, H., Kamalanathan, M., Quigg, A., Chin, W.-C., Santschi, P.H., 2018. The effects of sunlight on the composition of exopolymeric substances and subsequent aggregate formation during oil spills. Marine Chemistry 203, 49-54. the Deepwater Horizon oil spill, a large amount of marine oil snow (MOS) was formed in surface waters of the Gulf of Mexico (GOM) that eventually settled to the bottom. MOS consists of a microbially colonized matrix of extracellular polymeric substances (EPS), to which cells, and both ionic (e.g., trace nutrients, Ca2+) and non-ionic (e.g., toxic oil) substances can attach. The secretion of EPS is one of the microbial defense strategies against harmful or stressful environmental situations. In the surface waters, the toxicity of oil can be enhanced by elevated oxidative stress through UV radiation. To test the effects of sunlight on the composition and secretion of EPS and the subsequent aggregation process, we conducted short-term irradiation experiments in three treatments, i.e., control (GOM coastal seawater), water accommodated fraction of oil (WAF), and chemically-enhanced WAF (CEWAF). EPS composition (mainly carbohydrates and proteins) was quantified in the colloidal and aggregate fractions. In addition, bacterial abundance, live/dead cell ratio, particle size distribution, and the ambient hydroxyl radical (OH) formation rate were measured under these conditions. We found that in the presence of oil, natural sunlight stimulated polysaccharide secretion, coinciding with increased reactive oxygen species (ROS; i.e. OH) production. Moreover, formation of larger sized aggregates (>10?μm) was observed in the irradiated WAF treatments. The results support the hypothesis that sunlight plays an important role in MOS formation during an oil spill.Sun, R., Sun, Y., Li, Q.X., Zheng, X., Luo, X., Mai, B., 2018. Polycyclic aromatic hydrocarbons in sediments and marine organisms: Implications of anthropogenic effects on the coastal environment. Science of The Total Environment 640–641, 264-272. human activities aggravate environmental pollution, particularly in the coastal environment. Sixteen priority polycyclic aromatic hydrocarbons (PAHs) were determined in the sediments and marine species from Zhanjiang Harbor, a large harbor in China. The total PAH concentrations ranged from 151 to 453?ng/g dry weight (dw) in sediments and from 86.7 to 256?ng/g wet weight (ww) in organism tissues. High levels of PAHs occurred in the sample sites next to the estuary. A decrease in PAH levels was observed in comparison to the previous survey prior to 2012. Fish exhibited lower lipid weight normalized PAH concentrations than the other species, which may be related to their efficient metabolic transformation. Three ring PAHs dominated both in marine sediments and species, but low molecular weight PAHs exhibited higher proportions in biota than in sediments (p?<?0.05). Petrogenic and pyrolytic sources both contributed to the occurrence of PAHs, and the latter became increasingly important in the study area. The ecological risk from PAHs in the sediments was relatively low (9% incidence of adverse biological effect) according to the effects-based sediment quality guideline values. Exposure to PAHs via consuming seafoods might pose a health risk to local residents. Overall, these results revealed anthropogenic activities in the coastal area have an impact on the local ecosystem.Sun, Y.-F., Zhong, J.-R., Li, R., Zhu, T., Cao, X.-Y., Chen, G.-J., Wang, X.-H., Yang, L.-Y., Sun, C.-Y., 2018. Natural gas hydrate exploitation by CO2/H2 continuous Injection-Production mode. Applied Energy 226, 10-21. replacement is considered as a promising method for the simultaneous development of natural gas hydrate and CO2 sequestration. The addition of small molecular gases, such as N2 and H2, into the injected gas can increase the gas recovery ratio and prevent CO2 liquefaction. Based on previous studies, this work presents methane hydrate exploitation using the CO2/H2 continuous injection-production mode. The mechanism combines gas sweep with CH4/CO2 replacement. A series of experiments were carried out to optimize the injected gas composition and flow rate, which have a significant effect on the rate of CH4 hydrate decomposition, amount of CO2 sequestration, and cost. The compositions of the injected gases had little effect on the recovery rate when a relatively higher flow rate was employed. A balance between CH4 production and CO2 sequestration was established when the COCO2 2 mole fraction was slightly <74%, and the temperature of the reservoir did not decline throughout the whole process. The injection rate affected both the displacement efficiency and the production cost. Moreover, through these experiments, we discovered a more economically feasible and productive measure for regulating the injection rate.Super, J.R., Chin, K., Pagani, M., Li, H., Tabor, C., Harwood, D.M., Hull, P.M., 2018. Late Cretaceous climate in the Canadian Arctic: Multi-proxy constraints from Devon Island. Palaeogeography, Palaeoclimatology, Palaeoecology 504, 1-22. climate in the Late Cretaceous has long been recognized to have been warm and wet relative to the present, but quantitative assessments of paleoclimate have been challenging due, in part, to disagreements between proxies in marine and terrestrial environments. This study provides a first multiproxy evaluation of Late Cretaceous (~93–90?Ma to 73–72?Ma) paleoclimate and paleohydrology from Devon Island in the Canadian High Arctic (modern location: 76°17′N, 91°12′W; Late Cretaceous location: ~71°30′N, ~24°30′W). Surface temperatures are reconstructed at ~12.6 to 20.6?°C for the ocean and 11.7 to 16.9?°C over land, using glycerol dialkyl glycerol tetraether (GDGT) based proxies measured from marine (TEX86) and terrestrial samples (MBT′5ME). These proxies are likely skewed toward warm month temperatures, based on novel analysis and interpretation of biomarkers in sediment and co-occurring marine vertebrate coprolites. The hydrogen isotopic composition (δ2H) of precipitation is constrained to have varied from ?123‰ to ?82‰ (VSMOW) using evidence from n-alkanes likely derived from higher plants. δ18O of shelfal marine surface water is constrained to have been between ?10.5‰ to ?3.4‰, using phosphate oxygen isotopes of marine vertebrate teeth and coprolites. From these, marine salinity is modeled to have varied from 10 PSU and 30 PSU, indicative of periodic freshwater influx. These estimates indicate that large marine vertebrates lived and fed, at least intermittently, in near-shore brackish waters. Finally, the Arctic was similarly warm in both the Late Cretaceous and Paleocene/Eocene, but the Late Cretaceous isotopic composition of precipitation at Devon Island was enriched in the heavy isotope of hydrogen by up to +60 to +70‰ relative to Arctic Eocene sites. The combination of techniques used here reduces uncertainties related to the application of proxies to an environment without a modern analogue, providing novel paleoclimatic constraints on the Late Cretaceous Arctic region.Super, J.R., Thomas, E., Pagani, M., Huber, M., O’Brien, C., Hull, P.M., 2018. North Atlantic temperature and pCO2 coupling in the early-middle Miocene. Geology 46, 519-522. proxies indicate coupling between changes in atmospheric pCO2, global temperatures, and ice volume over much of the Cenozoic. Evidence has been presented for decoupling of these factors in the Miocene, though the cause of the apparent decoupling was uncertain. Here, we revisit Deep Sea Drilling Program (DSDP) Site 608 (24–9 Ma) in the North Atlantic Ocean, to provide improved constraints on sea-surface temperatures (SSTs) using the TEX86 and U37k' proxies, and use these to recalculate atmospheric pCO2. From the Oligocene/Miocene boundary to the middle Miocene Climatic Optimum (MCO, ca. 23.03 to ca. 14.5 Ma), SSTs at Site 608 were upward of 30 °C, nearly 15 °C warmer than modern. During the Middle Miocene Climatic Transition (MMCT), ca. 14.5 to ca. 12.5 Ma), SSTs cooled by ～6 °C. Lower SSTs persisted until the end of our record at 9 Ma. Our organic proxy derived SST estimates are considerably higher than those previously calculated from planktonic foraminiferal oxygen isotope data, leading to reassessed alkenone pCO2 estimates ～65 to ～175 ppm higher than previously calculated, with other assumptions held constant. A pCO2 decrease from an average of ～430 ppm in MCO to ～305 ppm after the MMCT, in step with the ～6 °C SST cooling, demonstrates coupling of climate and the carbon cycle, as well as a highly sensitive climate system.Sutherland, K.M., Wankel, S.D., Hansel, C.M., 2018. Oxygen isotope analysis of bacterial and fungal manganese oxidation. Geobiology 16, 399-411. ability of micro‐organisms to oxidize manganese (Mn) from Mn(II) to Mn(III/IV) oxides transcends boundaries of biological clade or domain. Many bacteria and fungi oxidize Mn(II) to Mn(III/IV) oxides directly through enzymatic activity or indirectly through the production of reactive oxygen species. Here, we determine the oxygen isotope fractionation factors associated with Mn(II) oxidation via various biotic (bacteria and fungi) and abiotic Mn(II) reaction pathways. As oxygen in Mn(III/IV) oxides may be derived from precursor water and molecular oxygen, we use a twofold approach to determine the isotope fractionation with respect to each oxygen source. Using both 18O‐labeled water and closed‐system Rayleigh distillation approaches, we constrain the kinetic isotope fractionation factors associated with O atom incorporation during Mn(II) oxidation to ?17.3‰ to ?25.9‰ for O2 and ?1.9‰ to +1.8‰ for water. Results demonstrate that stable oxygen isotopes of Mn(III/IV) oxides have potential to distinguish between two main classes of biotic Mn(II) oxidation: direct enzymatic oxidation in which O2 is the oxidant and indirect enzymatic oxidation in which superoxide is the oxidant. The fraction of Mn(III/IV) oxide‐associated oxygen derived from water varies significantly (38%–62%) among these bio‐oxides with only weak relationship to Mn oxidation state, suggesting Mn(III) disproportionation may account for differences in the fraction of mineral‐bound oxygen from water and O2. Additionally, direct incorporation of molecular O2 suggests that Mn(III/IV) oxides contain a yet untapped proxy of δ18OO2 of environmental O2, a parameter reflecting the integrated influence of global respiration, photorespiration, and several other biogeochemical reactions of global significance. Swann, G.E.A., Kendrick, C.P., Dickson, A.J., Worne, S., 2018. Late Pliocene marine pCO2 reconstructions from the subarctic Pacific Ocean. Paleoceanography and Paleoclimatology 33, 457-469. The development of large ice sheets across the Northern Hemisphere during the late Pliocene and the emergence of the glacial-interglacial cycles that punctuate the Quaternary mark a significant threshold in Earth's climate history. Although a number of different mechanisms have been proposed to initiate this cooling and the onset of major Northern Hemisphere glaciation, reductions in atmospheric concentrations of CO2 likely played a key role. The emergence of a stratified (halocline) water column in the subarctic northwest Pacific Ocean at 2.73?Ma has often been interpreted as an event which would have limited oceanic ventilation of CO2 to the atmosphere, thereby helping to cool the global climate system. Here diatom carbon isotopes (δ13Cdiatom) are used to reconstruct changes in regional carbon dynamics through this interval. Results show that the development of a salinity stratification did not fundamentally alter the net oceanic/atmospheric flux of CO2 in the subarctic northwest Pacific Ocean through the late Pliocene/early Quaternary. These results provide further insights into the long?term controls on global carbon cycling and the role of the subarctic Pacific Ocean in instigating global climatic changes.Swift, J.A., Roberts, P., Boivin, N., Kirch, P.V., 2018. Restructuring of nutrient flows in island ecosystems following human colonization evidenced by isotopic analysis of commensal rats. Proceedings of the National Academy of Sciences 115, 6392-6397.: The arrival of humans and human-introduced species to Pacific islands resulted in significant, long-lasting transformations to local ecosystems. However, direct measurements of deep-time human effects can be difficult to quantify from archaeological datasets. Isotopically reconstructed diet of the Pacific rat (Rattus exulans), a commensal species introduced by humans during one of the most dramatic archaeological examples of past human migration and ecosystem alteration, can provide insight into resource availability and utilization within the human-commensal niche. Our results highlight significant long-term restructuring of nutrient flows through ecosystems resulting from human arrival and subsequent land use on three Polynesian islands. We also demonstrate that stable isotope analysis of often-ignored commensal taxa represents a tool for tracking human activities and ecosystem effects more broadly.Abstract: The arrival of humans and human-introduced species to Pacific islands resulted in significant, long-lasting transformations to local ecosystems. However, direct measurements of deep-time human effects can be difficult to quantify from archaeological datasets. Isotopically reconstructed diet of the Pacific rat (Rattus exulans), a commensal species introduced by humans during one of the most dramatic archaeological examples of past human migration and ecosystem alteration, can provide insight into resource availability and utilization within the human-commensal niche. Our results highlight significant long-term restructuring of nutrient flows through ecosystems resulting from human arrival and subsequent land use on three Polynesian islands. We also demonstrate that stable isotope analysis of often-ignored commensal taxa represents a tool for tracking human activities and ecosystem effects more broadly.The role of humans in shaping local ecosystems is an increasing focus of archaeological research, yet researchers often lack an appropriate means of measuring past anthropogenic effects on local food webs and nutrient cycling. Stable isotope analysis of commensal animals provides an effective proxy for local human environments because these species are closely associated with human activities without being under direct human management. Such species are thus central to nutrient flows across a range of socionatural environments and can provide insight into how they intersected and transformed over time. Here we measure and compare stable carbon and nitrogen isotope data from Pacific rat (Rattus exulans) skeletal remains across three Polynesian island systems [Mangareva, Ua Huka (Marquesas), and the Polynesian Outlier of Tikopia] during one of the most significant cases of human migration and commensal introduction in prehistory. The results demonstrate widespread δ15N declines across these islands that are associated with human land use, intensification, and faunal community restructuring. Local comparison of rat stable isotope data also tracks human activities and resource availability at the level of the settlement. Our results highlight the large-scale restructuring of nutrient flows in island ecosystems that resulted from human colonization and ecosystem engineering activities on Pacific islands. They also demonstrate that stable isotope analysis of often-ignored commensal taxa can provide a tool for tracking human land use and environmental effects.Szymańska, E., 2018. Modern data science for analytical chemical data – A comprehensive review. Analytica Chimica Acta 1028, 1-10. and reliable analysis of chemical analytical data is a great challenge due to the increase in data size, variety and velocity. New methodologies, approaches and methods are being proposed not only by chemometrics but also by other data scientific communities to extract relevant information from big datasets and provide their value to different applications. Besides common goal of big data analysis, different perspectives and terms on big data are being discussed in scientific literature and public media. The aim of this comprehensive review is to present common trends in the analysis of chemical analytical data across different data scientific fields together with their data type-specific and generic challenges. Firstly, common data science terms used in different data scientific fields are summarized and discussed. Secondly, systematic methodologies to plan and run big data analysis projects are presented together with their steps. Moreover, different analysis aspects like assessing data quality, selecting data pre-processing strategies, data visualization and model validation are considered in more detail. Finally, an overview of standard and new data analysis methods is provided and their suitability for big analytical chemical datasets shortly discussed.Taheri-Shakib, J., Shekarifard, A., Naderi, H., 2018. Heavy crude oil upgrading using nanoparticles by applying electromagnetic technique. Fuel 232, 704-711. upgrading of heavy oil is one of the most important processes in heavy oil recovery due to the low quality of these types of oil. In this study, the effects of nanomaterials of Fe, titanium oxide (TO) and super activated carbon (CA) as catalysts in the process of upgrading heavy oil from the Azadegan Oilfield in Southwest Iran using microwave (MW) radiation are investigated. Samples of heavy oil are exposed for 2, 4, 6, 8 and 10?min to MW radiation with 4?wt% of each nanoparticle in each step. The results of the experiments show that Fe and TO nanoparticles have no significant effect on MW absorption in the initial 2 and 4?min intervals, while the CA nanoparticle, due to its higher potential for absorbing these waves, causes the temperature of the heavy oil sample to rise from the earliest time intervals. The presence of nanoparticles in heavy oil leads to a greater reduction in viscosity at initial and even longer intervals. In fact, these nanoparticles, by absorbing MWs over longer periods of time, cause cracking of heavier compounds the effect of which exceeds that of the loss of lighter compounds from the heavy oil. The CA catalyst has the highest viscosity reduction during the 6-min period and viscosity varies from 882.37?mPa.s to 791.19?mPa.s. The results of the analysis of carbon compounds (C), hydrogen (H), sulfur (S) and nitrogen (N) indicate that the presence of nanoparticles results in a further reduction of S and N in heavy oil than with MW radiation alone. The highest CA desulfurization over a period of 8?min is a reduction by 30.5%, while the highest H/C ratio occurs in the presence of this nanoparticle at 6?min. On the other hand, the lowest amount of N in the heavy oil sample is observed in the presence of the Fe nanoparticle with a decrease of 0.65?wt% at 10?min. According to Fourier transform infrared (FTIR) spectra, the presence of nanoparticles along with MW radiation reduces the concentration of OH, S-H, alkyl groups, carbonyl, carboxylic acid or derivative groups and aromatic compounds in heavy oil. These changes are more evident with CA and Fe nanoparticles. In terms of deasphalting heavy oil, the Fe nanoparticle has the greatest effectiveness with the asphaltene content reduced from 12.75?wt% to 9.13?wt% in 4?min. However, other nanoparticles reduced asphaltene components compared to MW radiation alone and promoted the process of reducing asphaltene content over longer periods. From the results of this study, it can be concluded that the use of nanoparticles with a higher potential for MW absorption can be more suitable options for the process of upgrading heavy oils. Moreover, the optimal duration of MW radiation in the presence of nanoparticles is one of the key parameters that varies greatly depending on the type of catalyst and the type of heavy oil.Tai, H.-C., Shen, Y.-P., Lin, J.-H., Chung, D.-T., 2018. Acoustic evolution of old Italian violins from Amati to Stradivari. Proceedings of the National Academy of Sciences 115, 5926-5931.: Amati and Stradivari violins are highly appreciated by musicians and collectors, but the objective understanding of their acoustic qualities is still lacking. By applying speech analysis techniques, we found early Italian violins to emulate the vocal tract resonances of male singers, comparable to basses or baritones. Stradivari pushed these resonance peaks higher to resemble the shorter vocal tract lengths of tenors or altos. Stradivari violins also exhibit vowel qualities that correspond to lower tongue height and backness. These properties may explain the characteristic brilliance of Stradivari violins. The ideal for violin tone in the Baroque era was to imitate the human voice, and we found that Cremonese violins are capable of producing the formant features of human singers.Abstract: The shape and design of the modern violin are largely influenced by two makers from Cremona, Italy: The instrument was invented by Andrea Amati and then improved by Antonio Stradivari. Although the construction methods of Amati and Stradivari have been carefully examined, the underlying acoustic qualities which contribute to their popularity are little understood. According to Geminiani, a Baroque violinist, the ideal violin tone should “rival the most perfect human voice.” To investigate whether Amati and Stradivari violins produce voice-like features, we recorded the scales of 15 antique Italian violins as well as male and female singers. The frequency response curves are similar between the Andrea Amati violin and human singers, up to ～4.2 kHz. By linear predictive coding analyses, the first two formants of the Amati exhibit vowel-like qualities (F1/F2 = 503/1,583 Hz), mapping to the central region on the vowel diagram. Its third and fourth formants (F3/F4 = 2,602/3,731 Hz) resemble those produced by male singers. Using F1 to F4 values to estimate the corresponding vocal tract length, we observed that antique Italian violins generally resemble basses/baritones, but Stradivari violins are closer to tenors/altos. Furthermore, the vowel qualities of Stradivari violins show reduced backness and height. The unique formant properties displayed by Stradivari violins may represent the acoustic correlate of their distinctive brilliance perceived by musicians. Our data demonstrate that the pioneering designs of Cremonese violins exhibit voice-like qualities in their acoustic output.Tan, Y., Pan, Z., Liu, J., Kang, J., Zhou, F., Connell, L.D., Yang, Y., 2018. Experimental study of impact of anisotropy and heterogeneity on gas flow in coal. Part I: Diffusion and adsorption. Fuel 232, 444-453. is adsorbed in the pores of coal matrix and during gas production gas is desorbed from the pore surface and diffuses through the matrix pore structure and flows in the fracture/cleat system to the production well or boreholes. However, coal is highly heterogeneous and anisotropic. How heterogeneity and anisotropy affect the gas storage and especially the diffusion behaviour is not well studied. In this work, a series of measurements were performed on three dry cubic coal samples cut from the same coal block from the Bowen Basin, Australia, using an adsorbing gas, methane. For each sample, gas adsorption experiments with gas flowing from three principal directions were performed. The diffusion data was fitted with a bidisperse diffusion model to obtain diffusion coefficient. The three samples, although from the same coal block, showed difference in adsorption amount and significant difference in effective diffusivity. It was found that the effective macropore diffusivity increased with gas pressure and effective micropore coefficient decreased with gas pressure. The effective diffusivity showed difference among samples and directions, demonstrating coal heterogeneity and anisotropy both have a significant impact on gas diffusion behaviour. However, no generalisation can be obtained with any single pore structure parameter, such as pore size or surface area, as it may be related to all pore and fracture structures at various scales.Tan, Y., Pan, Z., Liu, J., Zhou, F., Connell, L.D., Sun, W., Haque, A., 2018. Experimental study of impact of anisotropy and heterogeneity on gas flow in coal. Part II: Permeability. Fuel 230, 397-409. is highly anisotropic and heterogeneous, affecting coal permeability. As permeability is one of the most important reservoir properties for coalbed methane production, it is useful to understand the impact of coal anisotropy and heterogeneity on coal permeability. In this work, anisotropic permeability measurements were performed in the laboratory on three cubic samples from the same coal block from the Bowen Basin, Queensland, Australia. The permeability was measured at a series of gas and confining pressures. Cleat compressibility, a measure of permeability sensitivity to stress, was also calculated from the experimental results. Each sample was then scanned using microscopic X-ray computerised tomography after permeability measurements to study its cleat system. The results show that permeability is strongly anisotropic and heterogeneous among the three samples and is correlated with the cleat system. A permeability model, which incorporates stress, gas pressure and swelling effects, is used to describe the experimental results. At last, numerical simulations were conducted to demonstrate the impact of coal permeability heterogeneity on coalbed methane production.Tan, Z., Mao, L., Han, Y., Mo, D., Gu, H., Liu, Z., Long, Y., An, Z., 2018. Black carbon and charcoal records of fire and human land use over the past 1300?years at the Tongguan Kiln archaeological site, China. Palaeogeography, Palaeoclimatology, Palaeoecology 504, 162-169. examine fire patterns and landscape evolution in the Xiangjiang River Basin over the past 1300?years, high-resolution charcoal and black carbon (BC, char and soot) records from the Tongguan Kiln archaeological site of historical ceramic production have been analyzed in combination with robust Optically Stimulated Luminescence (OSL) and accelerator mass spectrometry radiocarbon (AMS14C) dating, archaeological documents, and paleo-environmental proxies (i.e., magnetic susceptibility, total organic carbon, XRF-derived elemental data, etc.).Throughout history, charcoal and BC have recorded changes in regional land use at the Tongguan Kiln site. Peaks in char and macro-charcoal contents indicate that local smoldering fire occurrences were typical with large amount of fuel used for kilns between 1300 and 1100?years?B.P. under wet climate conditions. These peaks coincided with the size of the Tongguan Kiln archaeological site, which led to reduction of forest cover from nearby mountains and activated soil erosion. Subsequently, the frequency of fire activity declined to a very low level between 1100 and 600?years?B.P., coupling with the decline of the Tongguan Kiln, and with a warm period in the study region. Over the past 600?years, with sharp growth in population, regional fires increased to an unprecedented scale for land reclamation for dry crop cultivation during a cold period, which in turn resulted in further environmental deterioration.In summary, shifts of fire patterns in the study site over the past 1300?years have been closely related to (1) climate variation; (2) the mode of human land use; and (3) vegetation type and fuel combustion efficiency. There was an interactive, complex relationship between these factors in the Xiangjiang River Basin, and these results suggest that the intensity and pattern of human land use could have further impacts on fire patterns and landscape evolution in response to climatic change of the East Asian Monsoon, in the past as well as in the future.Tanaka, K., Zelenitsky, D.K., Lü, J., DeBuhr, C.L., Yi, L., Jia, S., Ding, F., Xia, M., Liu, D., Shen, C., Chen, R., 2018. Incubation behaviours of oviraptorosaur dinosaurs in relation to body size. Biology Letters 14. birds sit on their eggs during incubation, a behaviour that likely evolved among non-avian dinosaurs. Several ‘brooding&#039; specimens of smaller species of oviraptorosaurs and troodontids reveal these non-avian theropods sat on their eggs, although little is known of incubation behaviour in larger theropod species. Here we examine egg clutches over a large body size range of oviraptorosaurs in order to understand the potential effect of body size on incubation behaviour. Eggshell porosity indicates that the eggs of all oviraptorosaurs were exposed in the nest, similar to brooding birds. Although all oviraptorosaur clutches consist of radially arranged eggs in a ring configuration, clutch morphology varies in that the central opening is small or absent in the smallest species, becomes significantly larger in larger species, and occupies most of the nest area in giant species. Our results suggest that the smallest oviraptorosaurs probably sat directly on the eggs, whereas with increasing body size more weight was likely carried by the central opening, reducing or eliminating the load on the eggs and still potentially allowing for some contact during incubation in giant species. This adaptation, not seen in birds, appears to remove the body size constraints of incubation behaviour in giant oviraptorosaurs.Tanasi, D., Greco, E., Noor, R.E., Feola, S., Kumar, V., Crispino, A., Gelis, I., 2018. 1H NMR, 1H-1H 2D TOCSY and GC-MS analyses for the identification of olive oil in Early Bronze Age pottery from Castelluccio (Noto, Italy). Analytical Methods 10, 2756-2763. development of analytical research in recent decades, at the edge between analytical chemistry and archaeology, provides new methods for the study of organic residues that are usually highly sensitive to natural decay. Using Nuclear Magnetic Resonance (NMR) and Gas Chromatography-Mass Spectrometry (GC-MS), it is now possible to chemically identify a series of natural substances preserved in archaeological environments. This paper presents a protocol to detect natural compounds, such as olive oil, from amorphous organic residues discovered inside the pores of prehistoric pottery from the Early Bronze Age settlement of Castelluccio (Noto, Italy), and dated to the end of the 3rd and the beginning of the 2nd millennium Before the Common Era (BCE).Tang, X., Zhang, J., Jiang, Z., Zhang, R., Lan, C., Zhao, W., Zhu, J., Wang, J., Zhao, P., 2018. Heterogeneity of organic-rich lacustrine marlstone succession and their controls to petroleum expulsion, retention, and migration: A case study in the Shulu Sag, Bohai Bay Basin, China. Marine and Petroleum Geology 96, 166-178. documented a new type of self-sourced unconventional reservoir consisting of interbedded organic-rich marlstone and calcareous conglomerates developed in lacustrine carbonate successions in the Eogene Shahejie formation (Es33) of Shulu Sag, Bohai Bay Basin. The Es33 interval used to be regarded as a set of homogeneous source rock for oil plays in the upper strata due to their high abundance of organic-matter. However, the Es33 interval actually has very strong heterogeneity in their organic richness and hydrocarbon generation ability among different stratigraphic sequences (the Es33 interval can be divided into sequence SQ1 to SQ5 from bottom to up). To better understand the heterogeneity in the unconventional reservoir and its effect on the hydrocarbon retention and migration, thin sections and scanning electronic microscopes were used to characterize the pore system in the reservoir, together with a amount of collected well database including wireline logging, gas logging, and physical property data (e.g. porosity and permeability). Intensive sampling from the Es33 interval of Well ST1H was performed and samples were measured with Rock-Eval and TOC analysis. The rock extracts were analyzed with SARA and gas chromatography - Mass spectrum (GC-MS) analysis to examine the fluid geochemical characteristics and molecular biomarkers composition. The results show that although the whole Es33 are characterized by low and ultra-low porosity and permeability, but the pore types in different lithology are different. The organic-rich marlstones develop large amount of organic matter pore and dissolved mineral pores, while the conglomerates developed inter-partical or inter-crystalline mineral pores dominantly. The sequence SQ2 has high quality of source rock for hydrocarbon generation, possessing moderate to high content of organic matter (TOC range 2–5?wt %) with Type I-II kerogen predominantly, basically in the thermal maturity stage of the peak oil window. OM and lithology play significant roles in controlling hydrocarbon expulsion and retention. Oil retained in the organic-rich marlstone was observed to absorb on the surface of OM and clay-rich matrix, which is also supported by the positive correlation between retained oil (represented by Rock-Eval S1) and TOC. Organic-lean conglomerates in the sequence SQ3 obtain abnormal high content of low mature oil determined by biomarker composition, which suggests the oil were derived from oil migration and mixture. Thermal maturity profile based on hydrocarbon biomarkers composition of rock extract provides a method to determine the effect of the hydrocarbon migration or retention within source rock. The organic-lean intervals adjacent or close to organic-rich source rock can be favorable targets for oil exploration.Tao, S., Zhao, X., Tang, D., Deng, C., Meng, Q., Cui, Y., 2018. A model for characterizing the continuous distribution of gas storing space in low-rank coals. Fuel 233, 552-557. quantitative characterization of pore size distribution in low-rank coal reservoirs is significant for the determination of gas content and evaluation of coalbed methane (CBM) development potential. However, each test method can only detect the limited pore size range and the measured data cannot be used comprehensively. In this paper, a continuous distribution model of pore space was constructed for coal reservoirs based on the measured data of mercury intrusion porosimetry (MIP) and low-temperature nitrogen adsorption (LTNA) experiments. This model can overcome the above weakness and obtain the complete pore size distribution from nanopores to microfractures. Through verifying and adjusting the whole structure model, it can be used to refine the gas storage space of low-rank coals. The simulation results show that the pore size distribution differs greatly for coal samples from different regions or even from the same region, which is consistent with the general feature of strong heterogeneity of coal reservoirs in China. Even though pores smaller than 100?nm are still dominate in low-rank coal reservoir, the average volume of pores larger than 100?nm can reach 37%, which is obviously higher than that in medium-high rank coal reservoir and provides effective space for the storage of large amount of free gas. With the increase of coalification degree, the percentage of pores smaller than 100?nm presents an increasing trend.Tarakki, N., Risk, D., Spafford, L., Fougère, C., 2018. A meta-analysis of the surface soil gas measurement monitoring and verification (MMV) program at the Aquistore project. International Journal of Greenhouse Gas Control 75, 189-197. Capture and Storage (CCS) is playing a greater role in reducing CO2 emissions. The Aquistore project at Estevan, Saskatchewan, Canada is an operational CCS demonstration and research site. Surface soil gas geochemistry is one method of Measurement, Monitoring, and Verification (MMV) techniques used for detection of leakage at CO2 injection sites. We have been operating the surface soil gas MMV program for several years, which has involved measuring gas concentrations of CO2, O2, N2, CH4, the stable isotope of CO2 (δ13C), and radiocarbon isotope Δ14CO2 as tracers for storage containment analysis. Soil CO2 surface flux measurements were also conducted during the baseline monitoring program. At Aquistore, CO2 concentration is typically elevated relative to the mean for the location, but such values are characteristic in this area. Ratio-based tracer analyses, such as O2 vs. CO2, CO2 vs. N2, and CO2 vs. N2/O2, all indicated that storage is secure. The Δ14CO2 values observed in soil gas were interesting in the parts of the site which had a more depleted baseline than expected. To date, there have been no changes in the soil gas indicators since the injections started. These observations will help to inform new research aimed at improving the effectiveness and efficiency of soil gas MMV at Aquistore and similar projects worldwide.Tasianas, A., Bünz, S., Bellwald, B., Hammer, ?., Planke, S., Lebedeva-Ivanova, N., Krassakis, P., 2018. High-resolution 3D seismic study of pockmarks and shallow fluid flow systems at the Sn?hvit hydrocarbon field in the SW Barents Sea. Marine Geology 403, 247-261. Barents Sea is an epicontinental shelf sea with a fragmented structure consisting of long fault complexes, basins and basement highs. Fluid leakage from deep-seated hydrocarbon accumulations is a widespread phenomenon and mostly related to its denudation history during the glacial/interglacial cycles. In this study, we aimed to better understand shallow fluid flow processes that have led to the formation of numerous pockmarks observed at the seabed, in this area. To achieve this goal, we acquired and interpreted high-resolution 3D seismic and multibeam swath bathymetry data from the Sn?hvit area in the Hammerfest Basin, SW Barents Sea. The high-resolution 3D seismic data were obtained using the P-Cable system, which consists of 14 streamers and allows for a vertical resolution of ~1.5?m and a bin size of 6.25?×?6.25?m to be obtained. The frequency bandwidth of this type of acquisition configuration is approximately 50–300?Hz. Seismic surfaces and volume attributes, such as variance and amplitude, have been used to identify potential fluid accumulations and fluid flow pathways. Several small fluid accumulations occur at the Upper Regional Unconformity separating the glacial and pre-glacial sedimentary formations. Together, these subsurface structures and fluid accumulations control the presence of pockmarks in the Sn?hvit study area. Two different types of pockmarks occur at the seabed: a few pockmarks with elliptical shape, up to a few hundred meters wide and with depths up to 12?m, and numerous circular, small, “unit pockmarks” that are only up to 20?m wide and up to 1?m deep. Both types of pockmarks are found within glacial ploughmarks, suggesting that they likely formed during deglaciation or afterwards. Some of the larger normal pockmarks show columnar leakage zones beneath them. Pressure and temperature conditions were favourable for the formation of gas hydrates. During deglaciation, gases may have been released from dissociating gas hydrates prolonging the period over which active seepage occurred. At present, there is no evidence from the 3D seismic data of active gas seepage in the Sn?hvit area. Low sedimentation rates or the influence of strong deep ocean currents may explain why these pockmarks can still be identified on the contemporary seabed.Tasker, T.L., Burgos, W.D., Piotrowski, P., Castillo-Meza, L., Blewett, T.A., Ganow, K.B., Stallworth, A., Delompré, P.L.M., Goss, G.G., Fowler, L.B., Vanden Heuvel, J.P., Dorman, F., Warner, N.R., 2018. Environmental and human health impacts of spreading oil and gas wastewater on roads. Environmental Science & Technology 52, 7081-7091. states in the United States allow the spreading of O&G wastewaters on roads for deicing or dust suppression. In this study, the potential environmental and human health impacts of this practice are evaluated. Analyses of O&G wastewaters spread on roads in the northeastern, U.S. show that these wastewaters have salt, radioactivity, and organic contaminant concentrations often many times above drinking water standards. Bioassays also indicated that these wastewaters contain organic micropollutants that affected signaling pathways consistent with xenobiotic metabolism and caused toxicity to aquatic organisms like Daphnia magna. The potential toxicity of these wastewaters is a concern as lab experiments demonstrated that nearly all of the metals from these wastewaters leach from roads after rain events, likely reaching ground and surface water. Release of a known carcinogen (e.g., radium) from roads treated with O&G wastewaters has been largely ignored. In Pennsylvania from 2008 to 2014, spreading O&G wastewater on roads released over 4 times more radium to the environment (320 millicuries) than O&G wastewater treatment facilities and 200 times more radium than spill events. Currently, state-by-state regulations do not require radium analyses prior to treating roads with O&G wastewaters. Methods for reducing the potential impacts of spreading O&G wastewaters on roads are discussed.Tathed, P., Han, Y., Misra, S., 2018. Hydrocarbon saturation in Bakken Petroleum System based on joint inversion of resistivity and dielectric dispersion logs. Fuel 233, 45-55. Petroleum System (BPS) is composed of both conventional and unconventional units, which exhibits significant variations in lithology, rock texture, clay content, total organic carbon, accompanied by high connate water salinity, presence of disseminated pyrite grains, and low values of porosity. These petrophysical attributes of the BPS lead to inconsistency in the oil-in-place estimates for those obtained from Electromagnetic (EM) induction log, Nuclear Magnetic Resonance (NMR) log, dielectric dispersion log measured by Array Dielectric Tool (ADT), and Dean-Stark core measurements. For purposes of improved hydrocarbon saturation estimation and petrophysical characterization in the BPS, a joint-inversion-based interpretation was performed on dispersive electrical conductivity and dielectric permittivity measurements at 4 dielectric-log-acquisition frequencies and 1 induction resistivity acquired at 20?kHz. This analysis was performed across a 350-ft depth interval in one of the science wells intersecting the BPS. Three geo-electromagnetic mixing models, namely Complex Refractive Index model, Stroud-Milton-De model, and Waxman Smits model are integrated and coupled to the inversion scheme to simultaneously estimate water saturation, formation brine conductivity, cementation exponent and saturation exponent in BPS.Water saturation estimates obtained using the proposed interpretation method were compared against those obtained from NMR log, Dean-Stark core measurements and service company’s dielectric inversion. In Middle Bakken from depth XX720 to XX750?ft, our estimates of water saturation are in better agreement with those estimated by service company’s mineral inversion method and service company’s dielectric interpretation as compared to those obtained from NMR interpretation and Dean Stark core measurement. Water saturation and formation brine conductivity estimates in Middle Bakken are in the ranges of 0.5–1 and 25–45?S/m, respectively. Inversion-derived brine conductivity and saturation exponent estimates are most uncertain in Lodgepole and Three Forks 2 formations, which exhibit a wide range of pore size distribution. Average relative errors in matching the 1 induction resistivity and 8 dielectric dispersion logs using the inversion-derived estimates are 33% and 20%, respectively, in the 350-ft depth interval of BPS. The proposed inversion achieves high certainty for the estimates when the formation has low clay content, low electrical anisotropy, and high porosity.Tavani, S., Balsamo, F., Granado, P., 2018. Petroleum system in supra-salt strata of extensional forced-folds: A case-study from the Basque-Cantabrian basin (Spain). Marine and Petroleum Geology 96, 315-330. accumulations in the Plataforma Burgalesa are located in structural traps that resulted from Mesozoic extensional forced folding. Pre-rift Triassic evaporites favoured the structural decoupling between faulted basement rocks and their supra-salt cover, which includes carbonate and fluvial reservoirs. These reservoir levels record severe syn-extension fracturing, related to the stretching of the supra-salt layers as extensional forced folding proceeded. The observed syn-extension fracture pattern has been partly modified by subsequent Cenozoic shortening. The availability of a large data set of seismic profiles, well data, oil shows, and the exposures of reservoir and seal levels, make the Plataforma Burgalesa an outstanding analogue for petroleum plays in extensional settings with supra-salt reservoirs. Here, we provide a reassessment of recently published structural data from the area, including geometry, kinematics, and fracture pattern of the partly inverted extensional forced fold system. We then compare structural features and occurrence of hydrocarbon accumulations, to discuss the implications for structural traps formation in rift basins with an intermediate décollement level.Telfer, M.W., Parteli, E.J.R., Radebaugh, J., Beyer, R.A., Bertrand, T., Forget, F., Nimmo, F., Grundy, W.M., Moore, J.M., Stern, S.A., Spencer, J., Lauer, T.R., Earle, A.M., Binzel, R.P., Weaver, H.A., Olkin, C.B., Young, L.A., Ennico, K., Runyon, K., 2018. Dunes on Pluto. Science 360, 992-997.: The surface of Pluto is more geologically diverse and dynamic than had been expected, but the role of its tenuous atmosphere in shaping the landscape remains unclear. We describe observations from the New Horizons spacecraft of regularly spaced, linear ridges whose morphology, distribution, and orientation are consistent with being transverse dunes. These are located close to mountainous regions and are orthogonal to nearby wind streaks. We demonstrate that the wavelength of the dunes (~0.4 to 1 kilometer) is best explained by the deposition of sand-sized (~200 to ~300 micrometer) particles of methane ice in moderate winds (<10 meters per second). The undisturbed morphology of the dunes, and relationships with the underlying convective glacial ice, imply that the dunes have formed in the very recent geological past.Editor's Summay. Methane ice dunes on Pluto: Wind-blown sand or ice dunes are known on Earth, Mars, Venus, Titan, and comet 67P/Churyumov-Gerasimenko. Telfer et al. used images taken by the New Horizons spacecraft to identify dunes in the Sputnik Planitia region on Pluto (see the Perspective by Hayes). Modeling shows that these dunes could be formed by sand-sized grains of solid methane ice transported in typical Pluto winds. The methane grains could have been lofted into the atmosphere by the melting of surrounding nitrogen ice or blown down from nearby mountains. Understanding how dunes form under Pluto conditions will help with interpreting similar features found elsewhere in the solar system.ten Kate, I.L., 2018. Organic molecules on Mars. Science 360, 1068-1069.: Variable levels of methane in the martian atmosphere have eluded explanation partly because the measurements are not repeatable in time or location. We report in situ measurements at Gale crater made over a 5-year period by the Tunable Laser Spectrometer on the Curiosity rover. The background levels of methane have a mean value 0.41 ± 0.16 parts per billion by volume (ppbv) (95% confidence interval) and exhibit a strong, repeatable seasonal variation (0.24 to 0.65 ppbv). This variation is greater than that predicted from either ultraviolet degradation of impact-delivered organics on the surface or from the annual surface pressure cycle. The large seasonal variation in the background and occurrences of higher temporary spikes (~7 ppbv) are consistent with small localized sources of methane released from martian surface or subsurface reservoirs.Editor's Summary: Measuring martian organics and methane. The Curiosity rover has been sampling on Mars for the past 5 years (see the Perspective by ten Kate). Eigenbrode et al. used two instruments in the SAM (Sample Analysis at Mars) suite to catch traces of complex organics preserved in 3-billion-year-old sediments. Heating the sediments released an array of organics and volatiles reminiscent of organic-rich sedimentary rock found on Earth. Most methane on Earth is produced by biological sources, but numerous abiotic processes have been proposed to explain martian methane. Webster et al. report atmospheric measurements of methane covering 3 martian years and found that the background level varies with the local seasons. The seasonal variation provides an important clue for determining the origin of martian methane.Them II, T.R., Gill, B.C., Caruthers, A.H., Gerhardt, A.M., Gr?cke, D.R., Lyons, T.W., Marroquín, S.M., Nielsen, S.G., Trabucho Alexandre, J.P., Owens, J.D., 2018. Thallium isotopes reveal protracted anoxia during the Toarcian (Early Jurassic) associated with volcanism, carbon burial, and mass extinction. Proceedings of the National Academy of Sciences 115, 6596-6601.. Declining oxygen contents in today’s oceans highlight the need to better understand ancient, natural marine deoxygenation and associated extinctions. In the Early Jurassic, the Toarcian Oceanic Anoxic Event (T-OAE; ～183 Ma) is associated with significant perturbations to the Earth system, historically defined by carbon isotopes. We reconstructed global oceanic (de)oxygenation using thallium isotopes from two ocean basins that suggest a stepwise decline of oxygen that initiated before and extended well after the classically defined T-OAE interval. This initial deoxygenation occurs with the start of massive volcanism and marine extinctions, while a later shift corresponds to the traditional T-OAE. This emphasizes the need for more nuanced records of ancient environmental and biogeochemical feedbacks that lead to and maintain widespread marine anoxia.Abstract. For this study, we generated thallium (Tl) isotope records from two anoxic basins to track the earliest changes in global bottom water oxygen contents over the Toarcian Oceanic Anoxic Event (T-OAE; ～183 Ma) of the Early Jurassic. The T-OAE, like other Mesozoic OAEs, has been interpreted as an expansion of marine oxygen depletion based on indirect methods such as organic-rich facies, carbon isotope excursions, and biological turnover. Our Tl isotope data, however, reveal explicit evidence for earlier global marine deoxygenation of ocean water, some 600 ka before the classically defined T-OAE. This antecedent deoxygenation occurs at the Pliensbachian/Toarcian boundary and is coeval with the onset of initial large igneous province (LIP) volcanism and the initiation of a marine mass extinction. Thallium isotopes are also perturbed during the T-OAE interval, as defined by carbon isotopes, reflecting a second deoxygenation event that coincides with the acme of elevated marine mass extinctions and the main phase of LIP volcanism. This suggests that the duration of widespread anoxic bottom waters was at least 1 million years in duration and spanned early to middle Toarcian time. Thus, the Tl data reveal a more nuanced record of marine oxygen depletion and its links to biological change during a period of climatic warming in Earth’s past and highlight the role of oxygen depletion on past biological evolution.Thuy, B., St?hr, S., 2018. Unravelling the origin of the basket stars and their allies (Echinodermata, Ophiuroidea, Euryalida). Scientific Reports 8, Article 8493., which include the spectacular basket stars, form a morphologically aberrant group of brittle stars. Surprisingly, the most recent molecular work found them to be sister to ophiurid brittle stars, thus challenging the traditional dichotomy between euryalids and non-euryalids, and leaving an enormous ghost lineage of more than 100 million years between the oldest unambiguous euryalid fossils and their predicted divergence from ophiurids during the Triassic. Here we examine both previously known and newly collected fossils to explore the evolutionary history of euryalids. A morphology-based phylogenetic estimate confirms the Triassic Aspiduriella as a basal member of the euryalid clade that superficially resembles members of the living ophiurid sister clades. Furthermore, we use lateral arm plates and vertebrae to identify two new Jurassic ophiuroids, Melusinaster alissawhitegluzae and Melusinaster arcusinimicus, as early euryalids that are morphologically intermediate between Aspiduriella and extant euryalids. Our phylogenetic analysis is the first to combine data from completely preserved skeletons and from microfossils in order to bridge morphological and stratigraphical gaps between the sampled taxa. It fills a major gap in the fossil record of euryalids and sets a robust phylogenetic framework to understand the morphological transition from ophiurid-like ancestors to the typical modern euryalids better.Tingay, M., Manga, M., Rudolph, M.L., Davies, R., 2018. An alternative review of facts, coincidences and past and future studies of the Lusi eruption. Marine and Petroleum Geology 95, 345-361. cause of the Lusi mud eruption remains controversial. The review by Miller and Mazzini (2017) firmly dismisses a role of drilling operations at the adjacent Banjarpanji-1 well and argues that the eruption was triggered by the M6.3 Yogyakarta earthquake some 254 km away. We disagree with these conclusions. We review drilling data and the daily drilling reports, which clearly confirm that the wellbore was not intact and that there was a subsurface blowout. Downhole pressure data from Lusi directly witness the birth of Lusi at the surface on the 29th of May 2006, indicating a direct connection between the well and the eruption. Furthermore, the daily drilling reports specifically state that Lusi activity was visibly altered on three separate occasions by attempts to kill the eruption by pumping dense fluid down the BJP-1 well, providing further evidence of a connection between the wellbore and Lusi. By comparison with other examples of newly initiated mud eruptions elsewhere by other earthquakes, the Yogyakarta earthquake was far away given its magnitude. The seismic energy density of the Yogyakarta earthquake was only 0.0043 J/m3, which is less than a quarter of the minimum 0.019 J/m3 seismic energy density that has ever been inferred to trigger other mud eruptions. We show that the Lusi area had previously experienced other shallow earthquakes with similar frequencies and stronger ground shaking that did not trigger an eruption. Finally, the data from the BJP-1 well indicates that there was no prior hydrodynamic connection between deep overpressured hydrothermal fluids and the shallow Kalibeng clays, and that there was no evidence of any liquefaction or remobilization of the Kalibeng clays induced by the earthquake. We thus strongly favor initiation by drilling and not an earthquake.Toledo, D., Irwin, P.G.J., Teanby, N.A., Simon, A.A., Wong, M.H., Orton, G.S., 2018. Uranus's northern polar cap in 2014. Geophysical Research Letters 45, 5329-5335.; In October and November 2014, spectra covering the 1.436 to 1.863‐μm wavelength range from the SINFONI Integral Field Unit Spectrometer on the Very Large Telescope showed the presence of a vast bright north polar cap on Uranus, extending northward from about 40°N and at all longitudes observed. The feature, first detected in August 2014 from Keck telescope images, has a morphology very similar to the southern polar cap that was seen to fade before the 2007 equinox. At strong methane‐absorbing wavelengths (for which only the high troposphere or stratosphere is sampled) the feature is not visible, indicating that it is not a stratospheric phenomenon. We show that the observed northern bright polar cap results mainly from a decrease in the tropospheric methane mixing ratio, rather than from a possible latitudinal variation of the optical properties or abundance of aerosol, implying an increase in polar downwelling near the tropopause level. Plain Language Summary: In this paper we show that Uranus's northern polar cap in 2014 results from a hole‐like depletion of methane rather than a formation or accumulation of aerosols as was previously thought. In this regard, our results provide key insights on the Uranus postequinox circulation as well as on the formation and nature of the different bright features observed before and after 2007 equinox in both hemispheres. Tourova, T.P., Sokolova, D.S., Semenova, E.M., Poltaraus, A.B., Nazina, T.N., 2018. Diversity of the alkB genes of n-alkane biodegradation in thermophilic hydrocarbon-oxidizing bacteria of the genera Geobacillus, Parageobacillus, and Aeribacillus. Microbiology 87, 301-307. of complete genomes of thermophilic bacteria of the genus Geobacillus, oxidizing n-alkanes and crude oil revealed the ladA gene and its homologues. In the genomes of some strains, the ladA gene was not detected, although they were capable of growth on n-alkanes. Cloning with degenerate primers has previously revealed eight homologues of the alkB gene (alkB-geo1–alkB-geo8) encoding alkane hydroxylases in Geobacillus. In the present work, investigation of the alkB genes of several new strains of thermophilic, hydrocarbon-oxidizing bacilli was carried out. In the clone libraries obtained using degenerate primers for the alkB genes from five strains of the genera Geobacillus, Parageobacillus, and Aeribacillus, mostly the universal homologous genes alkB-geo1 and alkB-geo4 were revealed. Additional PCR amplification with specific primers for each of the eight known alkB homologues revealed the universal homologous genes only in some of the studied strains. A correlation was found between the set of the alkB-geo3–alkB-geo6 homologus genes from Geobacillus subterraneus strain K amplified with specific primers and the previously revealed a set of these homologous genes transcripted at different cultivation conditions. This correlation may be due to accumulation of the copies of individual homologues under different cultivation conditions, which results in higher sensitivity of specific primers. The least common homologue, alkB-geo7, which was not detected in the relevant clone libraries, was found in two strains, indicating the possibility of development of more specific primers for amplification of this homologue in order to reveal hydrocarbon-oxidizing bacteria of related genera Geobacillus–Parageobacillus in molecular ecological research. Original Russian Text ? T.P. Tourova, D.Sh. Sokolova, E.M. Semenova, A.B. Poltaraus, T.N. Nazina, 2018, published in Mikrobiologiya, 2018, Vol. 87, No. 3.Tovar‐Herrera, O.E., Martha‐Paz, A.M., Pérez‐LLano, Y., Aranda, E., Tacoronte‐Morales, J.E., Pedroso‐Cabrera, M.T., Arévalo‐Ni?o, K., Folch‐Mallol, J.L., Batista‐García, R.A., 2018. Schizophyllum commune: An unexploited source for lignocellulose degrading enzymes. MicrobiologyOpen 7, e00637. represents the most abundant source of carbon in the Earth. Thus, fraction technology of the biomass turns up as an emerging technology for the development of biorefineries. Saccharification and fermentation processes require the formulation of enzymatic cocktails or the development of microorganisms (naturally or genetically modified) with the appropriate toolbox to produce a cost?effective fermentation technology. Therefore, the search for microorganisms capable of developing effective cellulose hydrolysis represents one of the main challenges in this era. Schizophyllum commune is an edible agarical with a great capability to secrete a myriad of hydrolytic enzymes such as xylanases and endoglucanases that are expressed in a high range of substrates. In addition, a large number of protein?coding genes for glycoside hydrolases, oxidoreductases like laccases (Lacs; EC 1.10.3.2), as well as some sequences encoding for lytic polysaccharide monooxygenases (LPMOs) and expansins?like proteins demonstrate the potential of this fungus to be applied in different biotechnological process. In this review, we focus on the enzymatic toolbox of S.?commune at the genetic, transcriptomic, and proteomic level, as well as the requirements to be employed for fermentable sugars production in biorefineries. At the end the trend of its use in patent registration is also reviewed.Tranchida, P.Q., Aloisi, I., Giocastro, B., Mondello, L., 2018. Current state of comprehensive two-dimensional gas chromatography-mass spectrometry with focus on processes of ionization. TrAC Trends in Analytical Chemistry 105, 360-366. present article contains information on current trends in the field of the hyphenated technology comprehensive two-dimensional gas chromatography-mass spectrometry, namely the most powerful analytical tool today-available for the analysis of mixtures formed of volatile compounds. The information herein reported relates mainly to a four-year time period (2014–2017). Focus is devoted to various aspects of mass spectrometry, in particular to ionization methodologies. Apart from critical considerations on past and present research, a future perspective on processes of ionization is given.Trapp, J., Gouveia, D., Almunia, C., Pible, O., Degli Esposti, D., Gaillard, J.-C., Chaumot, A., Geffard, O., Armengaud, J., 2018. Digging deeper into the pyriproxyfen-response of the amphipod Gammarus fossarum with a next-generation ultra-high-field Orbitrap analyser: new perspectives for environmental toxicoproteomics. Frontiers in Environmental Science 6, 54. doi: 10.3389/fenvs.2018.0005. proteins from sentinel species have been shown to be among the most relevant proteins to monitor the biological effects of anthropogenic contaminations. Shotgun proteomics allows high-throughput analysis of animal proteomes, but comprehensive coverage remains difficult to achieve due to the wide dynamic range. Here, the advantages of a new generation of mass analyser for environmental toxicoproteomics are documented through the identification of candidate biomarkers in a sentinel animal species for which the genome is as yet unsequenced. A label-free comparative proteomic study was performed on testis from the freshwater amphipod Gammarus fossarum challenged with 0.5 ?g or 50 ?g/L pyriproxyfen, a juvenile hormone analogue used as an insecticide. A total of 4,031 proteins could be monitored with a Q Exactive HF mass spectrometer incorporating an ultra-high-field Orbitrap analyser. Five times more MS/MS spectra and 4-fold more peptides and proteins were identified with this instrument compared to a LTQ Orbitrap XL spectrometer. Comparison of protein abundance between control and organisms exposed to 0.5 ?g or 50 ?g/L pyriproxyfen indicated that 32 and 21 proteins, respectively, were significantly modulated between test and control conditions. Functional annotation of these novel candidate biomarkers and their specificities are discussed in light of their potential applications in freshwater quality monitoring. The potential contribution of next-generation mass spectrometers to environmental toxicoproteomics is also touched on.Treu, L., Campanaro, S., Kougias, P.G., Sartori, C., Bassani, I., Angelidaki, I., 2018. Hydrogen-fueled microbial pathways in biogas upgrading systems revealed by genome-centric metagenomics. Frontiers in Microbiology 9, 1079. doi: 1010.3389/fmicb.2018.01079. upgrading via carbon dioxide hydrogenation is an emerging technology for electrofuel production. The biomethanation efficiency is strongly dependent on a balanced microbial consortium, whose high- resolution characterization along with their functional potential and interactions are pivotal for process optimization. The present work is the first genome-centric metagenomic study on mesophilic and thermophilic biogas upgrading reactors aiming to define the metabolic profile of more than 200 uncultivated microbes involved in hydrogen assisted methanogenesis. The outcomes from predictive functional analyses were correlated with microbial abundance variations to clarify the effect of process parameters on the community. The operational temperature significantly influenced the microbial richness of the reactors, while the H2 addition distinctively alternated the abundance of the taxa. Two different Methanoculleus species (one mesophilic and one thermophilic) were identified as the main responsible ones for methane metabolism. Finally, it was demonstrated that the addition of H2 exerted a selective pressure on the concerted or syntrophic interactions of specific microbes functionally related to carbon fixation, propionate and butanoate metabolisms. Novel bacteria were identified as candidate syntrophic acetate oxidizers (e.g., Tepidanaerobacter sp. DTU063), while the addition of H2 favored the proliferation of potential homoacetogens (e.g., Clostridia sp. DTU183). Population genomes encoding genes of Wood-Ljungdahl pathway were mainly thermophilic, while propionate degraders were mostly identified at mesophilic conditions. Finally, putative syntrophic interactions were identified between microbes that have either versatile metabolic abilities or are obligate/facultative syntrophs.Tse, T.J., Doig, L.E., Tang, S., Zhang, X., Sun, W., Wiseman, S.B., Feng, C.X., Liu, H., Giesy, J.P., Hecker, M., Jones, P.D., 2018. Combining high-throughput sequencing of sedaDNA and traditional paleolimnological techniques to infer historical trends in cyanobacterial communities. Environmental Science & Technology 52, 6842-6853. worldwide are under increasing pressure from anthropogenic activities and changing climate. Unfortunately, many inland waters lack sufficient long-term monitoring to assess environmental trends. Analysis of sedimentary ancient DNA (sedaDNA) is emerging as a means to reconstruct the past occurrence of microbial communities of inland waters. The purpose of this study was to assess a combination of high-throughput sequencing (16S rRNA) of sedaDNA and traditional paleolimnological analyses to explore multidecadal relationships among cyanobacterial community composition, the potential for cyanotoxin production, and paleoenvironmental proxies. DNA was extracted from two sediment cores collected from a northern Canadian Great Plains reservoir. Diversity indices illustrated significant community-level changes since reservoir formation. Furthermore, higher relative abundances in more recent years were observed for potentially toxic cyanobacterial genera including Dolichospermum. Correlation-based network analysis revealed this trend significantly and positively correlated to abundances of the microcystin synthetase gene (mcyA) and other paleoproxies (nutrients, pigments, stanols, sterols, and certain diatom species), demonstrating synchrony between molecular and more standard proxies. These findings demonstrate a novel approach to infer long-term dynamics of cyanobacterial diversity in inland waters and highlight the power of high-throughput sequencing to reconstruct trends in environmental quality and inform lake and reservoir management and monitoring program design.Tucker, J.M., Mukhopadhyay, S., Gonnermann, H.M., 2018. Reconstructing mantle carbon and noble gas contents from degassed mid-ocean ridge basalts. Earth and Planetary Science Letters 496, 108-119. fluxes of volatile elements from the mantle have long been used to understand mantle structure and evolution, and are critical controls on Earth's climate stability. Because of the ubiquity of magmatic degassing, inferring pre-degassing volatile concentrations from measured basalts requires the application of a degassing model. Such models, including the commonly-applied equilibrium Rayleigh distillation, typically assume equilibrium or solubility-based partitioning between melt and vapor. Here, we demonstrate that ratios of radiogenic isotopes of He, Ne, Ar and, especially, Xe measured in global mid-ocean ridge basalts (MORBs) are inconsistent with equilibrium degassing models, even when not considering He. We conclude that kinetic disequilibrium is a crucial process affecting volatile abundances during degassing. We present a simple disequilibrium Rayleigh distillation model to reconstruct pre-degassing MORB noble gas and carbon concentrations, which predicts that He and Ne achieve nearly equilibrium partitioning between melt and vesicles, but the slower-diffusing heavier noble gases are strongly affected by disequilibrium, resulting in non-equilibrium fractionation of noble gas elemental ratios, and other volatile element ratios like CO2/He.We apply our model to a large set of MORB data, and find average pre-degassing 3He, 22Ne, and 36Ar concentrations of 4.4 ± 0.9 × 10?10, 6.6 ± 1.4 × 10?11, and 6.8 ± 4.5 × 10?10 ccSTP/g (2σ), with variations of approximately 2 orders of magnitude, similar to other highly incompatible elements. Pre-degassing noble gas concentrations imply a mid-ocean ridge 3He flux of 800 ± 170 mol/yr and upper mantle 3He/22Ne and 3He/36Ar ratios of 6.6 ± 2.0 and 0.64 ± 0.44, but substantial variability in these ratios between samples. Applying our model to CO2, we calculate an average mantle CO2/3He molar ratio of 1.67 ± 0.21 × 109, which, when combined with our estimate of 3He flux, implies an upper mantle CO2 flux of 5.9 ± 1.0 × 1013 g/yr and a CO2 concentration of approximately 110 ppm.Our estimate of the mantle 3He flux is the first determined independently of oceanographic 3He measurements, and consequently represents a time-integrated flux substantially longer than ～1000 years. And although at the high end of the range of previous estimates, our estimate does not resolve the long-standing heat-helium paradox. Additionally, our requirement for heterogeneous pre-degassing 3He/22Ne and 3He/36Ar ratios between samples is contrary to conclusions of previous applications of disequilibrium degassing models, which advocated uniform ratios. Furthermore, we find that CO2/Ba ratios are highly variable in MORB samples, but still consistent with an average mantle mass ratio of ～100. However, estimating pre-degassing CO2 concentrations and the mantle CO2 flux depend strongly on the poorly-constrained carbon diffusivity. Consequently, our demonstration of the prevalence of disequilibrium during mid-ocean ridge degassing, and the potential for disequilibrium in other volcanic settings, highlights the need for better characterization of the physical parameters associated with volcanic degassing.Turtle, E.P., Perry, J.E., Barbara, J.M., Del Genio, A.D., Rodriguez, S., Le Mouélic, S., Sotin, C., Lora, J.M., Faulk, S., Corlies, P., Kelland, J., MacKenzie, S.M., West, R.A., McEwen, A.S., Lunine, J.I., Pitesky, J., Ray, T.L., Roy, M., 2018. Titan's meteorology over the Cassini Mission: Evidence for extensive subsurface methane reservoirs. Geophysical Research Letters 45, 5320-5328.: Cassini observations of Titan's weather patterns over >13?years, almost half a Saturnian year, provide insight into seasonal circulation patterns and the methane cycle. The Imaging Science Subsystem and the Visual and Infrared Mapping Spectrometer documented cloud locations, characteristics, morphologies, and behavior. Clouds were generally more prevalent in the summer hemisphere, but there were surprises in locations and timing of activity: Southern clouds were common at midlatitudes, northern clouds initially appeared much sooner than model predictions, and north polar summer convective systems did not appear before the mission ended. Differences from expectations constrain atmospheric circulation models, revealing factors that best match observations, including the roles of surface and subsurface reservoirs. The preference for clouds at mid-northern latitudes rather than near the pole is consistent with models that include widespread polar near-surface methane reservoirs in addition to the lakes and seas, suggesting a broader subsurface methane table is accessible to the atmosphere.Plain Language Summary: We monitored methane clouds in the atmosphere of Saturn's moon Titan for over 13 years, using images from the Cassini spacecraft. The observations cover almost half of Titan's year, showing how weather patterns changed from late southern summer to northern summer (approximately mid‐January through late June on Earth). During southern summer, extensive clouds and, on one occasion, rainfall were observed near Titan's south pole. But surprisingly, this weather pattern did not repeat at the north pole in northern summer. By comparing weather observations to atmospheric models, we can determine sources for the moisture in the atmosphere. Our analysis shows that, in addition to Titan's lakes and seas, there may also be liquid beneath the surface near both poles. This result is consistent with other evidence that suggests there may be underground connections between some of the lakes and seas. Knowing there may be more liquid below Titan's surface helps explain how methane is supplied to the atmosphere and how Titan's methane cycle works (similar to Earth's water cycle: evaporation, cloud formation, rain, and surface collection into rivers, lakes, and oceans). With the end of the Cassini mission, Earth‐based telescopes will continue to watch for large clouds on Titan. Uhlig, C., Kirkpatrick, J.B., D'Hondt, S., Loose, B., 2018. Methane-oxidizing seawater microbial communities from an Arctic shelf. Biogeosciences 15, 3311-3329. microbial communities can consume dissolved methane before it can escape to the atmosphere and contribute to global warming. Seawater over the shallow Arctic shelf is characterized by excess methane compared to atmospheric equilibrium. This methane originates in sediment, permafrost, and hydrate. Particularly high concentrations are found beneath sea ice. We studied the structure and methane oxidation potential of the microbial communities from seawater collected close to Utqiagvik, Alaska, in April 2016. The in situ methane concentrations were 16.3?±?7.2?nmol?L?1, approximately 4.8 times oversaturated relative to atmospheric equilibrium. The group of methane-oxidizing bacteria (MOB) in the natural seawater and incubated seawater was >?97?% dominated by Methylococcales (γ-Proteobacteria). Incubations of seawater under a range of methane concentrations led to loss of diversity in the bacterial community. The abundance of MOB was low with maximal fractions of 2.5?% at 200 times elevated methane concentration, while sequence reads of non-MOB methylotrophs were 4 times more abundant than MOB in most incubations. The abundances of MOB as well as non-MOB methylotroph sequences correlated tightly with the rate constant (kox) for methane oxidation, indicating that non-MOB methylotrophs might be coupled to MOB and involved in community methane oxidation. In sea ice, where methane concentrations of 82?±?35.8?nmol?kg?1 were found, Methylobacterium (α-Proteobacteria) was the dominant MOB with a relative abundance of 80?%. Total MOB abundances were very low in sea ice, with maximal fractions found at the ice–snow interface (0.1?%), while non-MOB methylotrophs were present in abundances similar to natural seawater communities. The dissimilarities in MOB taxa, methane concentrations, and stable isotope ratios between the sea ice and water column point toward different methane dynamics in the two environments.Valencia-Dávila, J.A., Witt, M., Blanco-Tirado, C., Combariza, M.Y., 2018. Molecular characterization of naphthenic acids from heavy crude oils using MALDI FT-ICR mass spectrometry. Fuel 231, 126-133. acid (NA) fractions from heavy crude oils are typically analyzed in mass spectrometry via electrospray ionization (ESI). Here, we show that NA analysis is also possible by MALDI using a highly basic matrix (proton sponge). When compared with ESI, that allowed detection of six compound families, MALDI resulted in the observation of twenty-two compound families. Besides, MALDI analysis affords compositional-dependent information. Unlike ESI, where all NAs are detected as deprotonated molecules, in MALDI we observe both deprotonated molecules and radical anions. This indicates that ion formation in NA by MALDI can occur by either acid-base and electron-capture mechanisms, or both. Interestingly, the preferred ionization channel seems to be compound class dependent; for instance, the acid base mechanism (which allows detection of deprotonated NA species through a Br?nsted-Lowry reaction) applies exclusively to NAs with high H/C ratios along the whole O/C range. On the other hand, for less saturated compounds both mechanisms apply, while the electron capture channel occurs exclusively in species with low H/C and high O/C ratios or high H/C and low O/C ratios (envelope of the van Krevelen plots). In summary, we demonstrate that MALDI(-) is an alternative method for the analysis of complex petrochemical samples offering additional advantages, when compared with ESI, such as increasing compositional space accessibility for polar samples, high throughput and exceptional tolerance to the presence of impurities and salts in the samples. Furthermore, exploration on semi-quantitative approaches in MALDI can provide additional advantages such as those offered by LC-ESI MS, currently used to quantify naphthenic acids.Valsala, R., Govindarajan, S.K., 2018. Interaction of dissolution, sorption and biodegradation on transport of BTEX in a saturated groundwater system: Numerical modeling and spatial moment analysis. Journal of Earth System Science 127, 53. of various physical, chemical and biological transport processes plays an important role in deciding the fate and migration of contaminants in groundwater systems. In this study, a numerical investigation on the interaction of various transport processes of BTEX in a saturated groundwater system is carried out. In addition, the multi-component dissolution from a residual BTEX source under unsteady flow conditions is incorporated in the modeling framework. The model considers Benzene, Toluene, Ethyl Benzene and Xylene dissolving from the residual BTEX source zone to undergo sorption and aerobic biodegradation within the groundwater aquifer. Spatial concentration profiles of dissolved BTEX components under the interaction of various sorption and biodegradation conditions have been studied. Subsequently, a spatial moment analysis is carried out to analyze the effect of interaction of various transport processes on the total dissolved mass and the mobility of dissolved BTEX components. Results from the present numerical study suggest that the interaction of dissolution, sorption and biodegradation significantly influence the spatial distribution of dissolved BTEX components within the saturated groundwater system. Mobility of dissolved BTEX components is also found to be affected by the interaction of these transport processes.van Bree, L.G.J., Peterse, F., van der Meer, M.T.J., Middelburg, J.J., Negash, A.M.D., De Crop, W., Cocquyt, C., Wieringa, J.J., Verschuren, D., Sinninghe Damsté, J.S., 2018. Seasonal variability in the abundance and stable carbon-isotopic composition of lipid biomarkers in suspended particulate matter from a stratified equatorial lake (Lake Chala, Kenya/Tanzania): Implications for the sedimentary record. Quaternary Science Reviews 192, 208-224. studied the distribution and stable carbon-isotopic (δ13C) composition of various lipid biomarkers in suspended particulate matter (SPM) from the water column of Lake Chala, a permanently stratified crater lake in equatorial East Africa, to evaluate their capacity to reflect seasonality in water-column processes and associated changes in the lake's phytoplankton community. This lake has large seasonal variation in water-column dynamics (stratified during wet seasons and mixing during dry seasons) with associated phytoplankton succession. We analyzed lipid biomarkers in SPM collected monthly at 5 depths (0–80?m) from September 2013 to January 2015. Seasonal variation in total phytoplankton biovolume is strongly reflected in the concentration of phytadienes, a derivative of the general photosynthetic pigment chlorophyll. The wax and wane of several specific biomarker lipids between June and December 2014 reflect pronounced phytoplankton succession after deep mixing, starting with a long and sustained chlorophyte bloom (reflected by C23:1, C25:1 and C27:1 n-alkenes, and C21 and C23 n-alkanes), followed by a peak in diatoms between July and October (loliolide and isololiolide), and then eustigmatophytes (C30 and C32 1,15 diols) once stratification resumes in October. Peak abundance of the C19:1 n-alkene during shallow mixing of the water column in January–February 2014 can be tentatively linked to the seasonal distribution of cyanobacteria. The concentration, seasonal variability, and low δ13C values of the C28 fatty acid in the SPM suggest that this biomarker is produced in the water column of Lake Chala instead of having the typically assumed vascular plant origin. The δ13C signature of particulate carbon and all aquatic biomarkers become increasingly more negative (by up to 16‰) during mixing-induced episodes of high productivity, whereas enrichment would be expected during such blooms. This reversed fractionation may be attributed to chemically enhanced diffusion, which generates depleted HCO3? under high pH (>9) conditions, as occur in the epilimnion of Lake Chala during periods of high productivity. The influence of this process can potentially explain previously observed 13C-depleted carbon signatures in the paleorecord of Lake Chala, and should be considered prior to paleorecord interpretation of organic-matter δ13C values derived (partially) from aquatic organisms in high-pH, i.e. alkaline, lakes.van de Waterbeemd, M., Tamara, S., Fort, K.L., Damoc, E., Franc, V., Bieri, P., Itten, M., Makarov, A., Ban, N., Heck, A.J.R., 2018. Dissecting ribosomal particles throughout the kingdoms of life using advanced hybrid mass spectrometry methods. Nature Communications 9, Article 2493. mass spectrometry has matured strongly over the past decades and has now reached a stage where it can provide deep insights into the structure and composition of large cellular assemblies. Here, we describe a three-tiered hybrid mass spectrometry approach that enables the dissection of macromolecular complexes in order to complement structural studies. To demonstrate the capabilities of the approach, we investigate ribosomes, large ribonucleoprotein particles consisting of a multitude of protein and RNA subunits. We identify sites of sequence processing, protein post-translational modifications, and the assembly and stoichiometry of individual ribosomal proteins in four distinct ribosomal particles of bacterial, plant and human origin. Amongst others, we report extensive cysteine methylation in the zinc finger domain of the human S27 protein, the heptameric stoichiometry of the chloroplastic stalk complex, the heterogeneous composition of human 40S ribosomal subunits and their association to the CrPV, and HCV internal ribosome entry site RNAs.Van Loon, L.R., Leupin, O.X., Cloet, V., 2018. The diffusion of SO42? in Opalinus Clay: Measurements of effective diffusion coefficients and evaluation of their importance in view of microbial mediated reactions in the near field of radioactive waste repositories. Applied Geochemistry 95, 19-24. experiments with 36Cl?, 35SO42? and HTO in Opalinus Clay (OPA) samples from a deep borehole in North-East Switzerland (Benken; BE) have been performed. The effect of burial depth on the experimental results has been investigated.It could be shown that the effective diffusion coefficients decrease with sample depth for all three tracers. Moreover, there was a good correlation with the texture of the samples. The diffusion coefficients for HTO are the largest (De?=?5.4–8.8?×?10?12?m2?s?1), followed by those for 36Cl? (De?=?0.7–1.9?×?10?12?m2?s?1), and finally 35SO42? (De?=?0.2–0.6?×?10?12?m2?s?1). 36Cl? was partially excluded from the total porosity resulting in an accessible porosity smaller than the total porosity (εCl?=?0.041–0.064). 35SO42?, on the other hand, showed interaction with OPA resulting in a capacity factor (α) larger than the total porosity (εtot?=?0.13–0.16). Using extended Archie's law the accessible porosity for 35SO42? was estimated between 0.013 and 0.030. This enabled to evaluate the sorption coefficient of 35SO42? from the measured capacity factor, resulting in values of Kd between 6?×?10?5 and 9?×?10?5?m3?kg?1.Venkatramani, A.V., Okuno, R., 2018. Mechanistic simulation study of expanding-solvent steam-assisted gravity drainage under reservoir heterogeneity. Journal of Petroleum Science and Engineering 169, 146-156. steam-assisted gravity drainage (ES-SAGD) is a potential method to reduce steam-oil ratio (SOR) of SAGD, which is a critical concern especially for highly-heterogeneous reservoirs. The main objective of this research is to investigate the flow characteristics of heterogeneous reservoirs in which solvent is more likely to lower SOR of SAGD.SAGD and ES-SAGD with normal hexane are simulated for fifty geostatistical realizations consisting of clean sand and shale, qualitatively representative of the middle member of the McMurray formation. Thermodynamic models are calibrated with experimental phase behavior data for reliable comparison between SAGD and ES-SAGD, including the water solubility in oil at elevated temperatures.Results show that the SOR reduction by steam-solvent coinjection is positively correlated with the increase in SAGD's SOR due to heterogeneity. Enhancement of bitumen flow by dilution is more important for lowering SOR for those reservoirs in which the permeability variation makes slow-flow regions during SAGD.Simulation results show that a larger amount of bitumen tends to be diluted by solvent in those reservoirs for which SAGD exhibits slow production of bitumen. Then, the observed results are analyzed by use of SAGD analytical equations that clarify several influential factors for bitumen flow beyond the edge of a steam chamber. It is shown that dilution of bitumen by solvent in steam-solvent coinjection becomes more significant where flow barriers limit the local bitumen flow under SAGD even at high temperatures. In such slow-flow regions, the bitumen flow rate can be substantially increased by accumulation of solvent in ES-SAGD, which reduces the oleic-phase viscosity and increases the oleic-phase saturation and, therefore, relative permeability. Solvent accumulation within a steam chamber can also reduce thermal losses because of lower operating-chamber temperatures.Vignola, C., Masi, A., Balossi Restelli, F., Frangipane, M., Marzaioli, F., Passariello, I., Rubino, M., Terrasi, F., Sadori, L., 2018. δ13C values in archaeological 14C‐AMS dated charcoals: Assessing mid‐Holocene climate fluctuations and human response from a high‐resolution isotope record (Arslantepe, Turkey). Rapid Communications in Mass Spectrometry 32, 1149-1162.: Past climate has always influenced human adaptation to the environment. In order to reconstruct palaeoclimate fluctuations and their role in the evolution of Near Eastern societies during the mid‐Holocene, high‐resolution Δ13C records from fossil wood remains at the archaeoloical site of Arslantepe (eastern Turkey) have been developed. Methods: After chemical treatment, δ13C values were measured by sample combustion flow using a FLASH EA‐CHNS instrument interfaced with a Delta V isotope ratio mass spectrometer via a CONFLO III. Two replicates per sample were analysed. The measurement precision was evaluated by propagating variations of the δ13C values of samples and V‐PDB standards, whereas the accuracy was checked by a quality control sample. To account for changes in atmospheric CO2, Δ13C values were calculated. In addition, 14C/12C ratios were measured by means of an AMS system (3 MV tandem accelerator). Results: Mean Δ13C curves of deciduous Quercus and Juniperus from archaeological levels between 4700 and 2000 bc (Arslantepe periods VIII‐VI D) were produced, where the isotope values were ordered by the available Radiocarbon ages. Interspecific variations of evergreen vs deciduous plants were postulated for the juniper Δ13C values being higher than 3‰. The seasonal rainfall amount was recorded by the juniper remains, while the water table levels were obtained from the oak samples. Conclusions: The local climate experienced times of enhanced/reduced precipitation in concert with regional trends. Anomalies in the air mass circulation from the Mediterranean basin also produced oscillations of rainfall amount. In such a frame the Rapid Climate Change dry events had a consistent signature in the Arslantepe Δ13C record, thus potentially contributing to social or organisational changes at the site.Vilcáez, J., York, J., Youssef, N., Elshahed, M., 2018. Stimulation of methanogenic crude oil biodegradation in depleted oil reservoirs. Fuel 232, 581-590. examined the feasibility of stimulating methanogenic crude oil biodegradation through the combined supply of CO2 and protein-rich matter in anaerobic microcosms, without the external supply of H2, and using formation waters and crude oil collected from the Stillwater and Cushing oil fields of Oklahoma, USA. We found that, depending on the chemical and microbiological composition of the formation water, protein-rich matter can stimulate methanogenic crude oil biodegradation if supplied along with CO2. For the low salinity (116, 714?mg/L) Stillwater oil field formation water, during the early stages of the stimulation process, CH4 was produced by the microbiological reduction of the supplied CO2 with H2 produced from the syntrophic/fermentative biodegradation of the supplied protein-rich matter. As indicated by 16S rRNA gene community analysis, this resulted in a syntrophic enrichment of a methanogenic crude oil-degrading microbial community and led to >42% crude oil biodegradation with the concurrent production of CH4 after 100?days of incubation at 50?°C. For the high salinity (176,665?mg/L) Cushing oil field formation water, although H2 was produced, enrichment of a methanogenic crude oil-degrading microbial community—and thus CH4 production—was not possible. We tested two types of protein-rich matter (yeast extract and isolated soy protein) and found that isolated soy protein can be used as a substitute for yeast extract in field-scale applications. These findings have large implications toward the coupling of geological CO2 storage and microbial enhanced oil recovery in depleted oil reservoirs.Villanueva, L., 2018. Engineering E. coli to have a hybrid Archaeal/Bacterial membrane. Trends in Microbiology 26, 559-560. and Archaea have membrane lipids with an opposite stereochemistry. The most plausible explanation for this differentiation implies an unstable heterochiral membrane stage. A recent study engineered Escherichia coli with a significant abundance of archaeal lipids showing higher robustness, disproving heterochirality as the driving force for this differentiation.Voosen, P., 2018. NASA Curiosity rover hits organic pay dirt on Mars. Science 360, 1054-1055. NASA's Curiosity rover landed on Mars in 2012, it has sifted samples of soil and ground-up rock for signs of organic molecules—the complex carbon chains that on Earth form the building blocks of life. Past detections have been so faint that they could be just contamination. Now, samples taken from two different drill sites on an ancient lakebed have yielded complex organic macromolecules that look strikingly similar to kerogen, the goopy fossilized building blocks of oil and gas on Earth. At a few dozen parts per million, the detected levels are 100 times higher than previous finds, but scientists still cannot say whether they have origins in biology or geology. The discovery positions scientists to begin searching for direct evidence of past life on Mars and bolsters the case for returning rock samples from the planet, an effort that begins with the Mars 2020 rover.Vosper, H., Chadwick, R.A., Williams, G.A., 2018. CO2 plume migration in underground CO2 storage: The effects of induced hydraulic gradients. International Journal of Greenhouse Gas Control 74, 271-281. use of water production as a pressure mitigation tool in the context of CO2 storage is widely studied but the impact it might have on the migration behaviour of a buoyant CO2 plume is less well reported. To investigate this further two different scenarios were modelled. In the first, a single water production well was used to draw CO2 along the strike of an open aquifer with a regional dip. Large rates of water production (5–10 times the volume of injected CO2) were required to achieve only small displacements of the CO2 plume. The second scenario investigated to what extent an induced hydraulic gradient might spill CO2 already stored in a structural trap. Here the effects were more pronounced with over 90% of the CO2 being spilled at a water cycling rate of 10 Mt per year (corresponding to a hydraulic gradient of 1.28?bar/km). The modelling was tested by the real case at Sleipner where CO2 migration in the Utsira Sand is potentially impacted by water production at the nearby Volve field. Simulations concluded that the CO2 plume at Sleipner should not be materially affected by water production from Volve and this is supported by the time-lapse seismics.Walker, S.I., Bains, W., Cronin, L., DasSarma, S., Danielache, S., Domagal-Goldman, S., Kacar, B., Kiang, N.Y., Lenardic, A., Reinhard, C.T., Moore, W., Schwieterman, E.W., Shkolnik, E.L., Smith, H.B., 2018. Exoplanet biosignatures: Future directions. Astrobiology 18, 779-824. introduce a Bayesian method for guiding future directions for detection of life on exoplanets. We describe empirical and theoretical work necessary to place constraints on the relevant likelihoods, including those emerging from better understanding stellar environment, planetary climate and geophysics, geochemical cycling, the universalities of physics and chemistry, the contingencies of evolutionary history, the properties of life as an emergent complex system, and the mechanisms driving the emergence of life. We provide examples for how the Bayesian formalism could guide future search strategies, including determining observations to prioritize or deciding between targeted searches or larger lower resolution surveys to generate ensemble statistics and address how a Bayesian methodology could constrain the prior probability of life with or without a positive detection.Wan, T., Mu, Z., 2018. The use of numerical simulation to investigate the enhanced Eagle Ford shale gas condensate well recovery using cyclic CO2 injection method with nano-pore effect. Fuel 233, 123-132. huge reserves of Eagle Ford shale gas condensate reservoirs have drawn great attention. The well productivity analysis indicates that the leading Eagle Ford is in reservoir decline stage. Condensate banking effect induces severer adverse effect on ultra-low permeability reservoirs and shale gas production than conventional reservoirs. The objective of this paper is to investigate the effect of CO2 huff-n-puff injection on mitigating condensate accumulation surrounding the induced fractures. The nano-pore confinement effect on condensate and gas production performance is considered. The nano-meter scale of shale condensate plays exhibit different phase behavior than conventional condensate reservoirs. The influence of nano-pore confinement on liquid phase behavior in shales is similar to adding CO2 in admixture with reservoir fluids, which acts to suppress the phase envelope. The interaction of CO2 injection with reservoir oil at molecular scale was discussed. Two scenarios including a lean gas condensate and rich gas condensate were compared in order to study the CO2 huff-n-puff performance with different reservoir fluids. The simulation results indicated that CO2 is more favorable in improving the rich condensate recovery. Removal of condensate accumulation in rich condensate Eagle Ford shale reservoirs by CO2 huff-n-puff injection results in substantial recovery increment in comparison with the pressure depletion scheme. This paper focuses on studying the influences of nano-pore walls on CO2 injection phase behavior in shale gas-condensate reservoirs.Wang, C., Bendle, J.A., Zhang, H., Yang, Y., Liu, D., Huang, J., Cui, J., Xie, S., 2018. Holocene temperature and hydrological changes reconstructed by bacterial 3-hydroxy fatty acids in a stalagmite from central China. Quaternary Science Reviews 192, 97-105. achieve a sufficient understanding of the spatial dynamics of terrestrial climate variability, new proxies and networks of data that cover thousands of years and run up to the present day are needed. Here we show the first Gram-negative bacterial 3-hydroxy fatty acid (3-OH-FA) based temperature and hydrological records from any paleoclimate archive globally. The data, covering the last 9 ka before present (BP), are generated from an individual stalagmite, collected from Heshang Cave, located on a tributary of the Yangtze River, central China (30°27′N, 110°25′E; 294?m). Our results indicate a clear early-to-middle Holocene Climatic Optimum (8.0–6.0 ka BP) followed by a long-term monotonic cooling and increasing variability over the last 0.9 ka BP. The hydrological record shows two relatively long wet periods (8.8–5.9 ka BP and 3.0–0 ka BP) and one relatively dry period (5.9–3.0 ka BP) in central China. We show that 3-OH-FA biomarkers hold promise as independent tools for paleoclimate reconstruction, with the potential to deconvolve temperature and hydrological signals from an individual stalagmite.Wang, C., Yang, S., Li, J., Li, X., Jiang, C., 2018. Influence of coal moisture on initial gas desorption and gas-release energy characteristics. Fuel 232, 351-361. and gas outbursts (hereinafter referred to as ‘outbursts’) result in serious damage and often occur in tectonically-deformed coal that is rich in gas. It has been demonstrated that the level of outburst risk declines with increasing coal moisture content. Moreover, an outburst generally lasts for mere tens of seconds and the required energy is mainly provided by the gas expansion energy. However, the gas desorption and energy release characteristics of tectonically deformed coal with different moisture contents during the first dozen seconds have not often been studied. In this study, a set of self-designed gas desorption equipment was used to carry out gas adsorption-desorption experiments in the first dozen seconds (about 13?s) on coal with different moisture contents. The results show that the drop rate of the gas pressure increases with an increase in coal moisture content, and the total amount of gas desorption and the mass flow rate of gas desorption reduce correspondingly in the gas desorption process. Moreover, the gas velocity also slows with increasing moisture content. Under different gas pressures, the total gas expansion energy (TGEE) and the total gas energy (TGE) released from the coal decrease with the increasing moisture content. Correspondingly, it takes a shorter time for coal to release 90% of the TGEE and the TGE. For all of the coal samples, the time taken for releasing 90% of the TGEE is shorter than that for releasing 90% of the TGE. Meanwhile, the ratio of TGEE in the TGE increases with the increasing moisture content. The TGEE accounts for 14–16% of the TGE released from coal samples of different moisture contents under different gas pressures.Wang, G., Wang, K., Wang, S., Elsworth, D., Jiang, Y., 2018. An improved permeability evolution model and its application in fractured sorbing media. Journal of Natural Gas Science and Engineering 56, 222-232. this paper, we consider fractured sorbing media (e.g., gas shale and coal bed methane reservoirs) as either dual porosity media comprising matrix-fracture or as triple porosity media comprising separate organic and inorganic matrix components and fractures. We accommodate the combination of mechanical deformation and desorption induced matrix shrinking in conditioning the evolution of fracture aperture and effective stress difference between each medium. These considerations result in an improved permeability evolution model (IPEM) for both dual porosity and triple porosity fractured sorbing media. Then we have simplified the model for triple porosity fractured sorbing media by reducing the geometry configuration from three dimensional to one dimensional, marked as SIPEM1. Specifically, SIPEM1 is a model simplified from the IPEM, and consider that when the size of the REV and the volumetric strain is small, replacing the volume with the side length of each layer medium in defining the model will bring relatively small error. This model is further simplified to SIPEM1-1 by assuming that the effective stress of each medium is the same. Then we have validated the models with field data. Finally, we compared prediction results from these models under different conditions. This study has found that IPEM is the most accurate model, especially for fractured sorbing media with a larger compressibility. SIPEM1-1 does not consider the difference of the effective stress of each medium and thus it is relatively less accurate in describing the evolution of permeability compared with SIPEM1 that considers this difference. This gap increases with the increase of permeability difference between fracture and matrix.Wang, K., Wang, T., Wang, Z., Luo, P., Li, Q., Fang, J., Ma, K., 2018. Characteristics and hydrocarbon geological conditions of the Changchengian rifts in the southern North China Craton. Acta Petrolei Sinica 39, 504-517. Meso-Neoproterozoic are wildly developed in North China Craton (NCC)with the distribution of Changchengian being the most extensive. Taking the Changchengian in the south NCC as study object, coupled with the isotopic chronological and petrological analyses, it suggests that the Xiong'er rift is a plume rift responding to the dispersion of Columbia supercontinent. Seismic data show that the Changchengian in southern part of Ordos Basin and Qinshui Basin covered by Phanerozoic strata respectively developed half graben-like rifts and garben rifts. Aeromagnetic data indicate that a rift system with strike of NE developed in the west to Xiong'er rift and the Qinshui Basin rift is the extension of the north branch of Xiong'er rift. The filling process of rifts can be divided into four stages. The early rift stage developed thick andesitic volcanic rocks; the later rift stage developed coarse clastic rocks; the sag stage developed relative fine clastic rocks; and epeiric sea stage developed carbonate rocks. Cuizhuang and Chenjiajian formations of sag stage developed dark argillaceous rocks and the black shale in Cuizhuang Formation is evaluated as effective source rock. Bitume was observed in the crack of dolostone of Luoyukou Formation. Longjiayuan Formation developed dissolved pores and large vugs. The argillaceous sandstone and muddy limestone of Lower Cambrian is the well cap rocks. These strata together with the underlying source rock in Cuizhuang Formation and reservoir in Luoyu Group, constitute the potential accumulation assemblage of Changchengian which could be still effective at present.Wang, Q., Pan, S., Bai, J., Chi, M., Cui, D., Wang, Z., Liu, Q., Xu, F., 2018. Experimental and dynamics simulation studies of the molecular modeling and reactivity of the Yaojie oil shale kerogen. Fuel 230, 319-330. this study, the chemical structural parameters of a kerogen from Yaojie oil shale were identified and investigated by using experimental data obtained from solid-state 13C nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, flash pyrolysis–gas chromatography–mass spectrometry, and Fourier transform infrared spectroscopy. Twelve constitutional isomers of the Yaojie 2D models with different grids and their corresponding 3D models were constructed by the combination of molecular simulation methods and multiple testing techniques. Finally, a reasonable 3D model of Yaojie kerogen was determined by a series of anneal dynamics simulations and geometry optimization calculations. From the results obtained by Mulliken population analysis and electron density analysis, the π–π conjugation effect among the aromatic ring structures is significantly impacted by the heteroatoms, leading to the accumulation of electrons on heteroatoms. Meanwhile, sulfur, oxygen, and nitrogen in the heterocyclic structures exhibited higher electronic charge density and considerably more reactivity compared with those of other atoms. Moreover, the molecular orbitals of HOMO and LUMO were calculated to examine the properties of chemical reaction of kerogen. The HOMO–LUMO energy gap indicated that the Yaojie kerogen exhibited higher reactivities compared to Type Ⅰ kerogen.Wang, Q., Peng, P.a., Zhang, W., Liu, J., Yu, C., 2018. Quantitative full-component hydrocarbon-generating simulation and crude oil mobility evaluation of shale in 7th Member of Yanchang Formation, Ordos Basin. Acta Petrolei Sinica 39, 541-553. oil and tight oil are current hot spots of oil and gas exploration, and the shale hydrocarbon-generating simulation experiment can provide important information for the exploration of these oil and gas resources. Taking the shale in 7th Member of Yanchang Formation (Chang-7 Member), Ordos Basin, the gold tube-autoclave hydrocarbon-generating simulator is used to systematically study the Type-II organic matter, the gaseous hydrocarbon (C1-5), light hydrocarbon (C6-14), heavy hydrocarbon (C14+), other components of hydrocarbon-generating products in the maturity range (Easy Ro 0.7% -1.6%) corresponding to "oil-generation window", and the geochemical characteristics of hydrocarbon generation residues. It is found that in the shale of Chang-7 Member during oil-generation period, gaseous hydrocarbons of 2.35-103.91 mL/g and light hydrocarbons of 10.83-88.24 mg/g are produced simultaneously. The peak yield of heavy hydrocarbons corresponds to Easy Ro of 1.00%, closely approaching to the maturities corresponding to the peak yield of saturated hydrocarbons, aromatics and non-hydrocarbons. Moreover, the asphaltene yield of heavy hydrocarbons starts to decline after reaching the Easy Ro of 1.35%, reflecting subsequent large scale of asphaltene cracking and solidification. However, the light/heavy ratio (gaseous hydrocarbon/light hydrocarbon) and gas/oil ratio (light hydrocarbon/heavy hydrocarbon) vital for physical property of crude oil are continuously increasing as the maturity getting higher, and the increasing rates are evidently accelerated after Easy Ro of 1.05% -1.15%. During oil-generating process, the massive loss of HI and H element of shale residue and the kerogen solid carbon isotope becoming heavier occur prior to Easy Ro of 1.00%; the kerogen solid carbon isotope changes less, and can be taken as an original source index in Ordos Basin. Through comparing six kinds of common biomarker maturity parameters in the hydrocarbon-generating products, it is validated that MPI and F1 among the PAH maturity are linearly correlated to maturity in the whole oil-generating window, and can be used to identify the crude oil maturity in the shale of Chang-7 Member in Ordos Basin. The change nodes of various geochemical characteristics of hydrocarbon-generating products and the maturity indexes can be applied to the exploitability assessment for shale oil or correlative tight oil in 7th Member of Yanchang Formation, Ordos Basin.Wang, S., Shi, J., Wang, K., Sun, Z., Miao, Y., Hou, C., 2018. Apparent permeability model for gas transport in shale reservoirs with nano-scale porous media. Journal of Natural Gas Science and Engineering 55, 508-519. mechanisms of gas transport in shale matrix pores is of great importance for more accurate production prediction of shale gas wells. Shale matrix is generally considered to be composed of organic matrix and inorganic matrix, and the gas transport mechanisms in different types of matrix pores are different. To date, most of the gas transport models assume that the gas transport channels in shale porous media are cylindrical capillaries or slits with uniform pore size, which ignore the effect of pore size distribution (PSD) on gas transport capacity. In addition, there are few transport models considering the presence of water in inorganic matrix, and the gas transport capacity will be overestimated ignoring this factor. Therefore, a real gas transport model for shale matrix pores is proposed so that the shale gas transport behavior can be analyzed more accurately. First, the nanopores in shale matrix is represented by cylindrical capillaries, and a logarithmic normal distribution function is utilized to characterize the PSD in shale organic and inorganic porous media. Then, the gas transport models are constructed for organic porous media and inorganic porous media, respectively. The total transport model can be obtained by coupling the two types of models. What is more, the influence of stress dependence and real gas effect are taken into account in the models. After that, the models are validated, which show that the proposed models fit well with published experimental data. Finally, the influence of multiple factors on gas transport capacity is analyzed, the results show that the total apparent permeability increases with the increase of total organic carbon (TOC) when the pressure is higher than 5?MPa, and it decreases with TOC as the pressure is lower than 5?MPa. The adsorption and desorption of gas in organic nanopores cannot be neglected, and its influence on slip flow is greater than that on Knudsen diffusion. The apparent permeability of inorganic nanopores decreases with relative humidity (water film thickness), and it decreases more rapidly when the relative humidity is higher than 0.5. The PSD has a great influence on shale gas transport capacity of porous media, especially for inorganic porous media.Wang, T., Jiang, L., Cai, C., Yuan, Y., Zhang, Y., Jia, L., Chen, S., 2018. Lipid evidence for oil depletion by sulfate-reducing bacteria during U mineralization in the Dongsheng deposit. Journal of Earth Science 29, 556-563. acids were extracted from fluid inclusions, and analyzed for distribution and individual δ13C values to determine if there exists sulfate-reducing bacteria (SRB) and what substrates SRB depleted during U mineralization in the Dongsheng deposit. The 10-methylhexadecanoic acid (10Me16:0) has been detected from most of the samples using GC-MS based on relative retention time and co-injection of standard 10Me16:0 compound. Samples with higher 10Me16:0 concentrations, show higher U contents. The presence of 10Me16:0 along with iso-ω7-cis-heptadecenoic acid (i17:1ω7c) and ω7-cis-octadecenoic acid (18:1ω7c) in the fluid inclusions may indicate the occurrence of SRB during the U mineralization. Saturated fatty-acids and unsaturated fatty-acids detected in this study have individual δ13C values from -30.3‰ to -28.5‰ and -30.5‰ to -27.9‰, respectively. These values are close to those of n-alkanes of the associated oils and the bulk oils, but significantly distinct from methane, thus the oils are concluded to have been used as substrate for the microorganisms to survive on. This proposal is supported by oil biodegradation and ore-stage calcite cement with δ13C values from -1.4‰ to -17.2‰.Wang, X., Cai, T., Wen, W., Zhang, Z., 2018. Effect of biosurfactant on biodegradation of heteroatom compounds in heavy oil. Fuel 230, 418-429. ability of biodegradation on heavy components in heavy oil is still a controversial issue, and the effect of biosurfactants on resins is unclear. Four strains and biosurfactant were used to investigate the degradation ability of resins using gas chromatography-mass spectrometry (GC–MS) and negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) by a stimulated aerobic biodegradation experiment. Results showed that the biosurfactant improved biodegradation rates for saturates, aromatics, resins, and asphaltenes by 115–231%, 130–168%, 116–161%, and 135–217%, respectively. The A/C value (the sum of relative abundance of the acyclic O2 species divided by the sum of relative abundance of the mono, di- and tri-cyclic acids) indicated that biosurfactants could accelerate the biodegradation process. Results also showed that the utilization preference of O-containing and N-containing compounds varies from different strains by analysing their distribution. A reduction in the relative abundance of N1O1 class was detected in all samples containing microorganisms only. A significant decrease in C27H48O and C28H50O was observed in all samples with the biosurfactant. Carbazoles, benzocarbazoles and dibenzocarbazaoles could be effectively used by the strain J2 with biosurfactant. The relative abundance of O1 class increased when treated with microorganisms only. However, it decreased in the presence of biosurfactants. Therefore, biosurfactant could alter the preference that microorganism utilized heteroatom compounds.Wang, X., Cawood, P.A., Zhao, H., Zhao, L., Grasby, S.E., Chen, Z.-Q., Wignall, P.B., Lv, Z., Han, C., 2018. Mercury anomalies across the end Permian mass extinction in South China from shallow and deep water depositional environments. Earth and Planetary Science Letters 496, 159-167. on Earth suffered its greatest bio-crisis since multicellular organisms rose 600 million years ago during the end-Permian mass extinction. Coincidence of the mass extinction with flood basalt eruptions in Siberia is well established, but the exact causal connection between the eruptions and extinction processes in South China is uncertain due to their wide spatial separation and the absence of direct geochemical evidence linking the two. The concentration and stable isotope analysis of mercury provides a way to test these links as its concentration is thought to be tied to igneous activity. Mercury/total organic carbon ratios from three Permian–Triassic boundary sections with a well-resolved extinction record in South China show elevated values (up to 900 ppb/wt.% relative to a background of <100 ppb/wt.%) that exactly coincides with the end-Permian mass extinction horizon. This enrichment does not show any correlation with redox and sedimentation rate variations during that time. Hg isotope mass-independent fractionation (Δ199Hg), with sustained positive values, indicate a predominant atmospheric-derived signature of volcanic Hg in deep-shelf settings of the Daxiakou and Shangsi sections. In contrast, the nearshore environment of the Meishan section displays a negative Δ199Hg signature, interpreted to be related to terrestrial Hg sources. Such temporal differences in Δ199Hg values shed new light on Hg geochemical behavior in marine settings, and also on the kill mechanisms associated with volcanism that were responsible for biotic mortality at the end of the Permian.Wang, X., Guo, C., He, S., Jiang, Z., Ma, Y., 2018. Improved skeleton extraction method considering surface feature of natural micro fractures in unconventional shale/tight reservoirs. Journal of Petroleum Science and Engineering 168, 521-532. micro fractures (MFs) developed in the ultra-tight formations (such as shale/tight reservoirs), which provide preferential channels for the fluids flow. Accurate characterization of such pore-fracture systems and suitable pore network models are the fundamentals of pore structure characterization and micro scale flow simulation. Conventional medial axis (MA) skeleton extraction method cannot preserve the fracture surface feature and connectivity information, which is not suitable for accurate pore scale simulation for these porous media with MFs. In this paper, a new skeleton model was proposed to distinguish MFs from pore space via extraction of surface points set of MFs. In the procedure of points set extraction, we improved the classic “MA based” shrink method to “medial surface (MS) based” method for the MFs characterization through introducing a new set of skeleton points (i.e., surface points and edge points of the micro fractures). The former describes their apertures and the latter is used for collecting connectivity information and determining the extension ranges of the MFs. Comparison of connectivity index, fracture length, Euclidean distance showed enhanced effectiveness and accuracy of the proposed method. The proposed method was applied in four ideal models and one field shale core sample. Results show that the proposed skeleton model can show more comprehensible forms of the real connected junction instead of the conventional ideal model. The extracted skeleton can also satisfy demands of the traditional skeleton extraction model and preserve the topology of the original pore-fracture space. This work proposed a more accurate method for pore-scale modeling in cores with natural MFs, and potentially applicable for pore scale flow simulations for tight/shale reservoirs.Wang, X., Pan, L., Lau, H.C., Zhang, M., Li, L., Zhou, Q., 2018. Reservoir volume of gas hydrate stability zones in permafrost regions of China. Applied Energy 225, 486-500. hydrate is a promising energy resource. Permafrost regions in China are natural gas hydrate prospects. In this study, we summarized the conditions for gas hydrate formation, and analyzed the probable thickness and area of gas hydrate stability zones in the permafrost regions in China. Then the probability of porosity within the gas hydrate stability zones was estimated from lithology, burial history, and compaction curves. Finally, the total reservoir volume for gas hydrate stability zones in permafrost regions was estimated from the joint probability distribution of the effective thickness, area, and porosity. The probable total reservoir volume of the gas hydrate stability zones in the permafrosts in China is in the range of 2.995?×?1012?m3 to 5.081?×?1012?m3, with the best estimate at 4.002?×?1012?m3. The Qinghai-Tibetan Plateau including Qilian (where the occurrence of natural gas hydrate has been proven by coring) has about 55% of the total reservoir volume of the gas hydrate stability zones in China, indicating it has a great resource potential. In the Mohe Basin the reservoir volume of the gas hydrate stability zone ranges from 0.49?×?1012?m3 to 0.79?×?1012?m3, suggesting it is a hopeful future resource exploration area. The best estimate of the total reservoir volume of the gas hydrate stability zones in Northwest China is 1.2?×?1012?m3 which is considerable. However, occurrence of gas hydrate is yet to be confirmed by future exploration. These estimates provide much needed data for further gas hydrate resource exploration and evaluation, as well as environmental protection.Wang, X., White, S.C., Balisi, M., Biewer, J., Sankey, J., Garber, D., Tseng, Z.J., 2018. First bone-cracking dog coprolites provide new insight into bone consumption in Borophagus and their unique ecological niche. eLife 7, Article e34773. canids have long been hypothesized to be North American ecological ‘avatars’ of living hyenas in Africa and Asia, but direct fossil evidence of hyena-like bone consumption is hitherto unknown. We report rare coprolites (fossilized feces) of Borophagus parvus from the late Miocene of California and, for the first time, describe unambiguous evidence that these predatory canids ingested large amounts of bone. Surface morphology, micro-CT analyses, and contextual information reveal (1) droppings in concentrations signifying scent-marking behavior, similar to latrines used by living social carnivorans; (2) routine consumption of skeletons; (3) undissolved bones inside coprolites indicating gastrointestinal similarity to modern striped and brown hyenas; (4) B. parvus body weight of ~24 kg, reaching sizes of obligatory large-prey hunters; and (5) prey size ranging ~35–100 kg. This combination of traits suggests that bone-crushing Borophagus potentially hunted in collaborative social groups and occupied a niche no longer present in North American ecosystems.Wang, Y.-P., Zou, Y.-R., Zhan, Z.-W., Lin, X.-H., Liang, T., 2018. Origin of natural gas in the Turpan-Hami Basin, NW China: Evidence from pyrolytic simulation experiment. International Journal of Coal Geology 195, 238-249. coal and carbonaceous mudstone collected from the Turpan-Hami Basin were pyrolysed in a closed system using a microscale sealed vessel (MSSV). The stable carbon isotope composition of methane, ethane and propane of pyrolysis gases were analysed and compared with the natural gases in the basin to identify their origin and post-genetic alteration. Similar origins of ethane and propane between pyrolysis gases and natural gases were observed in our studies. However, the methane of the natural gases experienced post-genetic alteration. Gases from Well Tuocan-1 of the Yilahu oil field and a number of wells in the Baka oil/gas field are the results of the admixture of oil-associated gas and coal-derived gas and of bio-degradation of coal-derived gas, respectively. The gas pools likely exist in volcanic rock below the Jurassic strata within the Turpan-Hami Basin, which was inferred from geochemical and geological evidence. Consequently, most of the natural gases in the Turpan-Hami Basin were probably the mixtures of matured coal-derived gases and the methane which diffused upward from gas pools at greater depth.Wang, Y., Li, X., Chen, B., Wu, W., Dong, D., Zhang, J., Han, J., Ma, J., Dai, B., Wang, H., Jiang, S., 2018. Lower limit of thermal maturity for the carbonization of organic matter in marine shale and its exploration risk. Petroleum Exploration and Development 45, 402-411. on the drilling data of the Silurian Longmaxi Formation in the Sichuan Basin and periphery, SW China, the Ro lower limits and essential features of the carbonization of organic matter in over-high maturity marine shale were examined using laser Raman, electrical and physical property characterization techniques. Three preliminary conclusions are drawn: (1) The lower limit of Ro for the carbonization of Type I-II1 organic matter in marine shale is 3.5%; when the Ro is less than 3.4%, carbonization of organic matter won't happen in general; when the Ro ranges from 3.4% to 3.5%, non-carbonization and weak carbonization of organic matter may coexist; when the Ro is higher than 3.5%, the carbonization of organic matter is highly likely to take place. (2) Organic-rich shale entering carbonization phase have three basic characteristics: log resistivity curve showing a general “slender neck” with low-ultralow resistance response, Raman spectra showing a higher graphite peak, and poor physical property (with matrix porosity of only less than 1/2 of the normal level). (3) The quality damage of shale reservoir caused by the carbonization of organic matter is almost fatal, which primarily manifests in depletion of hydrocarbon generation capacity, reduction or disappearance of organic pores and intercrystalline pores of clay minerals, and drop of adsorption capacity to natural gas. Therefore, the lower limit of Ro for the carbonization of Type I-II1 organic matter should be regarded as the theoretically impassable red line of shale gas exploration in the ancient marine shale formations. The organic-rich shale with low-ultralow resistance should be evaluated effectively in area selection to exclude the high risk areas caused by the carbonization of organic matter. The target organic-rich shale layers with low-ultralow resistance drilled during exploration and development should be evaluated on carbonization level of organic matter, and the deployment plan should be adjusted according to the evaluation results in time.Wang, Y., Liu, L., Ji, H., Song, G., Luo, Z., Li, X., Xu, T., Li, L., 2018. Origin and accumulation of crude oils in Triassic reservoirs of Wuerhe-Fengnan area (WFA) in Junggar Basin, NW China: Constraints from molecular and isotopic geochemistry and fluid inclusion analysis. Marine and Petroleum Geology 96, 71-93. Wuerhe-fengnan area (WFA) in the Junggar Basin, NW China, has recently obtained exploration success. These accumulations are characterized by oil from multiple source rocks with multiple-stage accumulation. However, the origin of oils and their charging history have been controversial, making it difficult to understand the general pattern of hydrocarbon accumulation. Here, we reconstruct this process mainly based on molecular and isotopic geochemistry of hydrocarbons and comprehensive fluid inclusion analysis. Four conclusions were reached. Firstly, oils in various regions came from different source rocks. The oil in the fault zone was derived from the Lower Permian Fengcheng Formation (P1f) argillaceous dolomite source rocks in situ in WFA and/or from Mahu depression. The oil in the slope area originated from the Middle Permian Lower Wuerhe Formation (P2w) mudstone source rocks in the Mahu depression. Secondly, oil reservoirs in various regions were charged at different times. Three episodes of P1f-sourced oil charging took place in Triassic reservoirs in the fault zone, which occurred at 230 Ma, 198 Ma and 125 Ma years ago, respectively. There are only two episodes of P2w-sourced oil charging in the slope area, namely, 196 Ma and 136 Ma before present. Thirdly, oil reservoirs in various regions have different hydrocarbon migration directions and mechanisms. Oils in the fault zone display obvious vertical migration characteristics. Hydrocarbons mainly migrated from lower structural positions to higher structural positions laterally, in other words, the hydrocarbons in the fault zone mainly migrated from southwest to northeast, while the hydrocarbons in the slope area mainly migrated from southeast to northwest. The oil migration in the fault zone is driven both by excessive formation pressure and buoyancy, while that in the slope area is likely driven by buoyancy. Finally, a comprehensive three-stage oil migration and accumulation model of Triassic reservoirs in WFA was established. The first-stage oil accumulation (P1f-sourced oils) occurred during the Middle Triassic (230 Ma), which was concentrated only in the fault zone. The second-stage and third-stage oil accumulation occurred during the Early Jurassic (200 Ma) and Early Cretaceous (140-120 Ma), respectively, with the P1f-sourced oils concentrated in the fault zone and the P2w-sourced oils concentrated in the slope area. In summary, oil reservoirs in various regions (fault zone and slope area) were derived from different source rocks, with different charging time and accumulation models.Wang, Y., Liu, S., Zhao, Y., 2018. Modeling of permeability for ultra-tight coal and shale matrix: A multi-mechanistic flow approach. Fuel 232, 60-70. transport in coal and shale matrices does not always fall into the continuum flow regime described by Darcy’s law. Rather, a considerable portion of this transport is sporadic and irregular when the mean free path of gas becomes comparable to the prevailing pore scale. A nonlinear process influenced by non-Darcy flow components like gas sorption, gas slippage, and diffusion occurs throughout gas recovery. Therefore, a new permeability model with pressure-dependent weighting factors is presented to describe gas flow. This model contains the coupling of matrix flow with explaining the impact of both multiple flow regimes and stress-strain relationship on unconventional gas permeability evolution. The stress-strain relationships were derived from thermal-elastic equations and can be incorporated into the fracture-based flow component, enabling permeability prediction under uniaxial strain and hydrostatic conditions. The “U-shape” permeability trends caused by flow dynamics and geomechanical effects are observed in modeling results, which match experimental data. The agreement between modeling results and experimental data shows that gas permeability can be fully characterized by the presented model. This model has the ability to predict uniaxial strain permeability to hydrostatic permeability in a laboratory scale.Wang, Y., Spencer, R.G.M., Podgorski, D., Kellerman, A., Rashid, H., Zito, P., Xiao, W., Wei, D., Yang, Y., Xu, Y., 2018. Spatiotemporal transformation of dissolved organic matter along an alpine stream flowpath on the Qinghai-Tibetan Plateau: importance of source and permafrost degradation. Biogeosciences Discussions 2018, 1-34. Qinghai-Tibetan Plateau (QTP) accounts for approximately 70?% of global alpine permafrost and is an area sensitive to climate change. The thawing and mobilization of ice and organic carbon-rich permafrost impact hydrologic conditions and biogeochemical processes on the QTP. Despite numerous studies of Arctic permafrost, there are no reports to date for the molecular-level in-stream processing of permafrost-derived dissolved organic matter (DOM) on the QTP. In this study, we examine temporal and spatial changes of chemical composition of DOM and 14C age of dissolved organic carbon (DOC) along an alpine stream (3850–3207?m above sea level) by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), accelerator mass spectrometry (AMS) and UV-visible spectroscopy. Compared to downstream sites, the DOM at the headstream exhibited older radiocarbon (14C-DOC) age, higher mean molecular weight, higher aromaticity and fewer polyunsaturated components. At the molecular level, 6409 and 1345 formulas were identified as unique to the active layer (AL) leachate and permafrost layer (PL) leachate, respectively. Comparing permafrost leachates to the downstream site, 59?% of AL-specific formulas and 90?% of PL-specific formulas were degraded, likely a result of rapid instream degradation of permafrost-derived DOM. From peak discharge in the summer to low flow in late autumn, the DOC concentration at the headstream site decreased from 13.9 to 10.2?mg/L, while the 14C-DOC age increased from 745 to 1560 years before present (BP), reflecting an increase in relative contribution of deep permafrost carbon due to the effect of changing hydrological conditions over the course of the summer on DOM source (AL vs. PL). Our study thus demonstrates that hydrological conditions impact the mobilization of permafrost carbon in an alpine fluvial network, the signature of which is quickly lost through in-stream metabolism.Wang, Z., Cheng, Y., Zhang, K., Hao, C., Wang, L., Li, W., Hu, B., 2018. Characteristics of microscopic pore structure and fractal dimension of bituminous coal by cyclic gas adsorption/desorption: An experimental study. Fuel 232, 495-505. characteristics of micropore (0.32–2?nm), mesopores (2–50?nm) and fractal dimensions of bituminous coal during the process of cyclic gas adsorption/desorption were revealed by combining N2 (77?K) and CO2 (273?K) adsorption experiments from microscopic aspect. The results indicate that the pore structure characterization in the coal matrix are changed, resulting in decreased mesopore volumes and increased micropore volumes. The mesopore volumes are mainly constituted by the pores of 10–20, and 20–30?nm, and it will increase at first and then decrease with the increasing pressures. The maximum change of micropore volume reaches 65.6%, indicating a great effect on the micropores influenced by pressures. In addition, the main micropore size range, major peak and the model diameter of coals all increase with the increasing pressures, the higher the adsorb pressure is, the higher swelling is. With the help of the conceptual models, we then analyzed the variation reasons, which may be result from transformation of mesopores and the connection of the inaccessible pores. D1 and D2 in #1 and D2 in #2 all increase with the increasing adsorption pressures, enhancing the roughness of surface and complexity of structure, while D1 in #2 shows an opposite property. The study of variations of microscopic pore structure by cyclic adsorption/desorption was aimed at providing new understanding for the exploration of the changes of diffusion and permeability.Wang, Z., Liu, H., Cao, Y., 2018. Choosing a suitable εw-p by distinguishing the dominant plant sources in sediment records using a new Pta index and estimating the paleo-δDp spatial distribution in China. Organic Geochemistry 121, 161-168. hydrogen isotopic composition of plant wax (δDwax) inherits the isotopic values of the source water and isotopic fractionation that take place in lipid biosynthesis. The δDwax values of n-alkanes or n-acids in sediment records are considered to be effective paleo-δD for precipitation proxies for different timescales. However, the vegetation effect also contributes substantially to the apparent fractionation values (εw-p) between the precipitation and plant. Therefore, a method for evaluating the dominant plant source in the sediment records is key for reconstructing a reliable paleo-δDp record. In this study, based on field data from the extremely arid Qaidam Basin and the semi-arid central Chinese Loess Plateau (CLP), a plant type index (Pta), based on the traditional Paq and n-alkane C31/C29 index, was used to evaluate the dominant plant type that contributed to the sediments. In the arid and semi-arid region, the Pta values of the aquatic plants were <90, while the shrub Pta ranged from 90 to 180 and the grass Pta was >180. A test on contemporary soils and surface lake sediments also showed that the Pta index could estimate the regional vegetation distribution in modern environments. We also evaluated the dominant n-alkane source for four sediment records in China during the last millennium and reconstructed a regional paleo-δDp by choosing a different εw-p. The estimated paleo-δDp values showed a good correlation with the modern regional summer δDp. We suggest that a large number of field studies are needed to improve the Pta index for quantitatively calculating the precise ratios for various plant sources. Such data would play a key role in improving hydrogen isotopic hydroclimatic research.Warden, L., Moros, M., Weber, Y., Sinninghe Damsté, J.S., 2018. Change in provenance of branched glycerol dialkyl glycerol tetraethers over the Holocene in the Baltic Sea and its impact on continental climate reconstruction. Organic Geochemistry 121, 138-154. Baltic Sea is an enclosed basin that experienced a number of different salinity phases during the Holocene corresponding to the establishment of a connection with the North Sea. Branched glycerol dialkyl glycerol tetraethers (brGDGTs) in surface sediments and Holocene sedimentary successions from the Gotland and Arkona Basins were analyzed to examine their potential applicability as indicators for soil organic matter input, as well as their suitability for paleoclimate reconstructions. Our results show a marked change in brGDGT distributions and the branched and isoprenoid tetraether (BIT) index. The transition of the Ancylus Lake (fresh) to the Littorina Sea (brackish) phase is revealed by a large drop in the BIT index and an increase in the MBT′5Me, which reveals a large shift in provenance of the sedimentary brGDGTs. During the lake phase, brGDGTs are presumed to be primarily produced by in situ production in the water column. During the brackish phase, in situ brGDGT production in the alkaline pore waters of the surface sediments (as revealed by their high degree of cyclization) was predominant although there was evidence of occasional input of soil-derived brGDGTs. The predominant aquatic autochthonous production of brGDGTs does not allow the use of brGDGTs for continental air temperature reconstructions but they can be used for bottom water and lake temperature reconstructions during some intervals. The results from this study demonstrate that geological changes and concomittant salinity variations can be revealed by the provenance of brGDGTs.Warke, M.R., Schr?der, S., Strauss, H., 2018. Testing models of pre-GOE environmental oxidation: A Paleoproterozoic marine signal in platform dolomites of the Tongwane Formation (South Africa). Precambrian Research 313, 205-220. facies of the upper Tongwane Formation preserve a largely overlooked record of pre-GOE Paleoproterozoic seawater. This inventory has survived despite a complex paragenetic history involving both diagenetic and contact metamorphic processes. BIF mineral assemblages are dominated by a medium-grade grunerite overprint and the formation of prograde and retrograde riebeckite. The massive dolomite member, a platform top carbonate which caps the succession, is characterized by marine REYSN patterns lacking significant negative CeSN anomalies (<10%) and δ13Ccarb values of between +1.83 and +2.95 ‰VPDB that are slightly elevated above Paleoproterozoic ‘normal marine’ values. Systematically decreasing δ13Ccarb values measured in monotonously recrystallized, talc bearing, slope carbonates reflect interaction with devolatilization fluids during contact metamorphism caused by the intrusion of the Bushveld Igneous Complex; slope carbonates offer no insight into marine paleoredox conditions. Thus, despite contact metamorphism, Paleoproterozoic marine signals are retained in platform-top dolomites, however they do not support claims for widespread oxygen accumulation in shallow depositional environments of the Transvaal Basin on the eve of the GOE.Washburn, A.M., Hudson, S.M., Selby, D., Abdullayev, N., Shiyanova, N., 2018. Re‐Os geochronology and chemostratigraphy of the Maikop series source rocks of eastern Azerbaijan. Journal of Petroleum Geology 41, 411-416. Oligocene – Miocene Maikop Series is a world‐class source interval and is the most important source rock for the petroleum systems of the South Caspian Basin and surrounding region. The Maikop is a thick (up to 3 km) succession of silty mudstones with intervals of high organic carbon content. However correlation of organic‐rich intervals within the South Caspian Basin and beyond to basins of the Eastern Paratethys is problematic. Current age constraints are based primarily on microfaunal assemblages, but the assemblages are lacking in precision and are sparsely dispersed. This study provides a numerical age datum for Maikopian strata that may be used to improve correlation of organic‐rich intervals both locally and regionally. The age date obtained was produced via Re‐Os isotope geochronology. Of the five sample suites analyzed, one Re‐Os data‐set yielded an isochron of 17.2 ± 3.2 Ma. Re‐Os data sets that failed to produce statistically meaningful isochrons provide qualitative age constraints by comparing calculated initial 187Os/188Os ratios from these samples to187Os/188Os ratios in seawater through time.Webster, C.R., Mahaffy, P.R., Atreya, S.K., Moores, J.E., Flesch, G.J., Malespin, C., McKay, C.P., Martinez, G., Smith, C.L., Martin-Torres, J., Gomez-Elvira, J., Zorzano, M.-P., Wong, M.H., Trainer, M.G., Steele, A., Archer, D., Sutter, B., Coll, P.J., Freissinet, C., Meslin, P.-Y., Gough, R.V., House, C.H., Pavlov, A., Eigenbrode, J.L., Glavin, D.P., Pearson, J.C., Keymeulen, D., Christensen, L.E., Schwenzer, S.P., Navarro-Gonzalez, R., Pla-García, J., Rafkin, S.C.R., Vicente-Retortillo, ?., Kahanp??, H., Viudez-Moreiras, D., Smith, M.D., Harri, A.-M., Genzer, M., Hassler, D.M., Lemmon, M., Crisp, J., Sander, S.P., Zurek, R.W., Vasavada, A.R., 2018. Background levels of methane in Mars’ atmosphere show strong seasonal variations. Science 360, 1093-1096. Curiosity rover has been sampling on Mars for the past 5 years (see the Perspective by ten Kate). Eigenbrode et al. used two instruments in the SAM (Sample Analysis at Mars) suite to catch traces of complex organics preserved in 3-billion-year-old sediments. Heating the sediments released an array of organics and volatiles reminiscent of organic-rich sedimentary rock found on Earth. Most methane on Earth is produced by biological sources, but numerous abiotic processes have been proposed to explain martian methane. Webster et al. report atmospheric measurements of methane covering 3 martian years and found that the background level varies with the local seasons. The seasonal variation provides an important clue for determining the origin of martian methane.Science, this issue p. 1096, p. 1093; see also p. 1068Variable levels of methane in the martian atmosphere have eluded explanation partly because the measurements are not repeatable in time or location. We report in situ measurements at Gale crater made over a 5-year period by the Tunable Laser Spectrometer on the Curiosity rover. The background levels of methane have a mean value 0.41 ± 0.16 parts per billion by volume (ppbv) (95% confidence interval) and exhibit a strong, repeatable seasonal variation (0.24 to 0.65 ppbv). This variation is greater than that predicted from either ultraviolet degradation of impact-delivered organics on the surface or from the annual surface pressure cycle. The large seasonal variation in the background and occurrences of higher temporary spikes (~7 ppbv) are consistent with small localized sources of methane released from martian surface or subsurface reservoirs.Wei, M., Liu, J., Elsworth, D., Wang, E., 2018. Triple-porosity modelling for the simulation of multiscale flow mechanisms in shale reservoirs. Geofluids 2018, Article 6948726. gas reservoir is a typical type of unconventional gas reservoir, primarily because of the complex flow mechanism from nanoscale to macroscale. A triple-porosity model (M3 model) comprising kerogen system, matrix system, and natural fracture system was presented to describe the multispace scale, multitime scale, and multiphysics characteristic of gas flows in shale reservoir. Apparent permeability model for real gas transport in nanopores, which covers flow regime effect and geomechanical effect, was used to address multiscale flow in shale matrix. This paper aims at quantifying the shale gas in different scales and its sequence in the process of gas production. The model results used for history matching also showed consistency against gas production data from the Barnett Shale. It also revealed the multispace scale process of gas production from a single well, which is supplied by gas transport from natural fracture, matrix, and kerogen sequentially. Sensitivity analysis on the contributions of shale reservoir permeability in different scales gives some insight as to their importance. Simulated results showed that free gas in matrix contributes to the main source of gas production, while the performance of a gas shale well is strongly determined by the natural fracture permeabilityWei, W., Frei, R., Gilleaudeau, G.J., Li, D., Wei, G.-Y., Chen, X., Ling, H.-F., 2018. Oxygenation variations in the atmosphere and shallow seawaters of the Yangtze Platform during the Ediacaran Period: Clues from Cr-isotope and Ce-anomaly in carbonates. Precambrian Research 313, 78-90. late Neoproterozoic Era witnessed a significant oxygenation in Earth’s surface in line with the naissance and diversity of early animals; however, detailed variations of the oxygenation during this period remain controversial. Chromium-isotope in ancient carbonates has shown its ability to trace the oxygenation history of the atmosphere-hydrosphere system. In this study, we analyzed Cr-isotope and Ce-anomaly data of carbonates from the Ediacaran Doushantuo and Dengying formations in the Yangtze Gorges area, South China, in order to reconstruct oxygenation variations in the atmosphere and shallow seawaters of the Yangtze Platform during the Ediacaran Period.After evaluating and excluding detrital and diagenetic effects, well-preserved δ53Crauth signatures were obtained. Post-Marinoan carbonates record slightly positive δ53Crauth values (0.18–0.43‰) and slightly negative Ce-anomaly, suggesting generally oxidizing conditions in the atmosphere (with pO2 over 1% PAL) and in shallow seawaters of the Yangtze Platform during the post-Marinoan phase, which may have been related to the diversity of early Ediacaran organisms. Shuram/Wonoka correlative carbonates are characterized by the fluctuations of δ53Crauth values (?0.25 to 0.97‰) and a significant negative δ13C excursion, which may have resulted from partial oxidation of the large deep-water DOC reservoir under enhanced oxidative weathering conditions. This process released 13C-depleted carbon into DIC pool and isotopically unfractionated Cr (III) into water columns, the latter of which immediately precipitated by adsorption onto the detrital materials. Meanwhile, an increase in local anoxia (and even euxinia) in the intrashelf basin of the Yangtze Platform driven by enhanced microbial sulfate reduction and the resultant H2S, possibly limited regional biological evolution during this phase. Late Ediacaran carbonates record elevated δ53Crauth values (0.40–0.96‰) together with the decreasing trend in Ce/Ce? values, indicating a more oxygenated environment in the atmosphere and shallow seawaters of the Yangtze Platform during the late Ediacaran phase, which may have been beneficial to the diversification of late Ediacaran animals.Wells, N.S., Kappelmeyer, U., Kn?ller, K., 2018. Anoxic nitrogen cycling in a hydrocarbon and ammonium contaminated aquifer. Water Research 142, 373-382. fate and transport through contaminated groundwater systems, where N is both ubiquitous and commonly limits pollutant attenuation, must be re-evaluated given evidence for new potential microbial N pathways. We addressed this by measuring the isotopic composition of dissolved inorganic N (DIN?=?NH4+, NO2?, and NO3?) and N functional gene abundances (amoA, nirK, nirS, hszA) from 20 to 38 wells across an NH4+, hydrocarbon, and SO42? contaminated aquifer. In-situ N attenuation was confirmed on three sampling dates (0, +6, +12 months) by the decreased [DIN] (4300 - 40 μM) and increased δ15N-DIN (5‰–33‰) over the flow path. However, the assumption of negligible N attenuation within the plume was complicated by the presence of alternative electron acceptors (SO42?, Fe3+), both oxidizing and reducing functional genes, and N oxides within this anoxic zone. Active plume N cycling was corroborated using an NO2? dual isotope based model, which found the fastest (～10 day) NO2? turnover within the N and electron donor rich central plume. Findings suggest that N cycling is not always O2 limited within chemically complex contaminated aquifers, though this cycling may recycle the N species rather than attenuate N.Wen, T., Niu, X., Gonzales, M., Zheng, G., Li, Z., Brantley, S.L., 2018. Big groundwater data sets reveal possible rare contamination amid otherwise improved water quality for some analytes in a region of Marcellus Shale development. Environmental Science & Technology 52, 7149-7159. thousand groundwater samples collected in the 2010s in an area of Marcellus shale-gas development are analyzed to assess spatial and temporal patterns of water quality. Using a new data mining technique, we confirm previous observations that methane concentrations in groundwater tend to be naturally elevated in valleys and near faults, but we also show that methane is also more concentrated near an anticline. Data mining also highlights waters with elevated methane that are not otherwise explained by geologic features. These slightly elevated concentrations occur near 7 out of the 1,385 shale-gas wells and near some conventional gas wells in the study area. For ten analytes for which uncensored data are abundant in this 3,000 km2 rural region, concentrations are unchanged or improved as compared to samples analyzed prior to 1990. Specifically, TDS, Fe, Mn, sulfate, and pH show small but statistically significant improvement, and As, Pb, Ba, Cl, and Na show no change. Evidence from this rural area could document improved groundwater quality caused by decreased acid rain (pH, sulfate) since the imposition of the Clean Air Act or decreased steel production (Fe, Mn). Such improvements have not been reported in groundwater in more developed areas of the U.S.Wendebourg, J., Biteau, J.-J., Grosjean, Y., 2018. Hydrodynamics and hydrocarbon trapping: Concepts, pitfalls and insights from case studies. Marine and Petroleum Geology 96, 190-201. contacts are observed in many oil and gas fields. They are generally attributed to the effect of hydrodynamics. Hydrodynamic flow exists in almost all geological basin types of the Wilson cycle, from passive margins to foreland basins to mountain chains. There are various geological processes driving regional hydrodynamics. Flow is regulated by permeability variations which are given by the geological framework. The role of faults as partial permeability barriers may be a significant regulator for flow. Hydrodynamics is best recognized by using the principles of hydraulic head. However, hydraulic data must be carefully interpreted to avoid pitfalls such as transition zones where variable oil saturation may be falsely interpreted as tilted contacts.In sedimentary basins, we distinguish two different hydrodynamic settings where flow is either mainly gravity-driven (or centripetal), or mainly compaction-driven (or centrifugal). In both cases, hydrodynamics can enhance hydrocarbon trapping. Gravity driven processes are particularly important in the Arabian Shield and North Africa. Centrifugal and centripetal phenomena can co-exist in the same basin, e.g. Mahakam delta or Douala Basin. Turbidites occur typically in centrifugal settings.Hydrodynamic concepts applied to petroleum exploration are not frequently used in industry despite being known for a long time. They may however become increasingly important in conventional exploration as static plays are rapidly being drilled up and the remaining exploration potential of sedimentary basins is increasingly affected by stratigraphic and hydrodynamic trapping components.Wierzbowski, H., Bajnai, D., Wacker, U., Rogov, M.A., Fiebig, J., Tesakova, E.M., 2018. Clumped isotope record of salinity variations in the Subboreal Province at the Middle–Late Jurassic transition. Global and Planetary Change 167, 172-189. of clumped isotope, oxygen isotope and elemental (Mg/Ca, Sr/Ca) analyses of exceptionally well-preserved belemnite rostra and ammonite shells from the uppermost Callovian–Upper Kimmeridgian (Lamberti–Mutabilis zones) of the Russian Platform are presented. Despite a significant decrease in belemnite δ18O values across the Upper Oxfordian–Lower Kimmeridgian, the clumped isotope data show a constant seawater temperature (ca. 16?°C) in the studied interval. The decrease in belemnite δ18O values and lower δ18O values measured from ammonite shells are interpreted as a result of the salinity decline of the Middle Russian Sea of ca. 12‰, and salinity stratification of the water column, respectively. The postulated secular palaeoenvironmental changes are linked to the inflow of subtropical, saline waters from the Tethys Ocean during a sea-level highstand at the Middle–Late Jurassic transition, and progressive isolation and freshening of the Middle Russian Sea during the Late Oxfordian–Kimmeridgian.The obtained clumped isotope data demonstrate relative stability of the Late Jurassic climate and a paramount effect of local palaeoceanographic conditions on carbonate δ18O record of shallow epeiric seas belonging to the Subboreal Province. Variations in Mg/Ca and Sr/Ca ratios of cylindroteuthid belemnite rostra, which are regarded by some authors as temperature proxies, are, in turn, interpreted to be primarily dependent on global changes in seawater chemistry.The paleoenvironmental variations deduced from clumped and oxygen isotope records of the Russian Platform correspond well with changes in local cephalopod and microfossil faunas, which show increasing provincialism during the Late Oxfordian and the Early Kimmeridgian. Based on the review of literature data it is suggested that the observed salinity decrease and restriction of Subboreal basins during the Late Jurassic played a major role in the formation of periodic bottom water anoxia and sedimentation of organic rich facies.Wild, B., Imfeld, G., Guyot, F., Daval, D., 2018. Early stages of bacterial community adaptation to silicate aging. Geology 46, 555-558. silicate weathering rates over large space and time scales remains limited by current understanding of mineral reactivity. In particular, relating mineral-microorganism interactions to the temporal decrease of silicate weathering rates resulting from surface aging is still not fully understood. Here we examine the interplay between bacteria from natural soil solutions and tailored (fresh or aged) mineral powders aimed at simulating short- and long-term fluid-mineral interactions. Mineral-specific bacterial communities developed within 7 weeks on mineral surfaces and were not significantly affected by chemical modifications of the silicate surface resulting from laboratory aging (i.e., development of amorphous silica-rich surface layers, ASSLs). Dissolution rates of aged mineral powders remained one order of magnitude lower than those of fresh powders, despite a small increase of the dissolution rate (≤30%) for biotic experiments with olivine powders. This increase could be attributed to bacterial mobilization of iron during bacterial colonization of olivine surfaces devoid of ASSLs. Bacteria did not restore the reactivity of aged powders by active hydrolysis of the ASSLs, and thus may not counterbalance mineral surface aging in the critical zone over longer time scales.Witts, J.D., Landman, N.H., Garb, M.P., Boas, C., Larina, E., Rovelli, R., Edwards, L.E., Sherrell, R.M., Cochran, J.K., 2018. A fossiliferous spherule-rich bed at the Cretaceous–Paleogene (K–Pg) boundary in Mississippi, USA: Implications for the K–Pg mass extinction event in the Mississippi Embayment and Eastern Gulf Coastal Plain. Cretaceous Research 91, 147-167. describe an outcrop of the Cretaceous–Paleogene (K–Pg) boundary exposed due to construction near New Albany, Union County, Mississippi. It consists of the Owl Creek Formation and overlying Clayton Formation. The Owl Creek Formation is rich in the ammonites Discoscaphites iris and Eubaculites carinatus, which, along with biostratigraphically important dinoflagellate cysts and calcareous nannofossils, indicate deposition occurred within the last 1 million years, most likely last 500?kyrs, of the Cretaceous. The base of the overlying Clayton Formation marks the K–Pg boundary, and consists of a 15–30?cm thick muddy, poorly sorted quartz sand containing abundant spherules representing ejecta derived from the Chicxulub impact event. Impact spherules range in size from 0.5?mm to 1?mm in diameter and are hollow and well preserved, with details such as smaller vesicular spherules enclosed within. The spherules are altered to clay minerals such as smectite and are typical of those found at K–Pg boundary sites in the Gulf of Mexico and beyond. Spherules are scattered throughout the bed, and surface counts suggest an average of 4 spherules per cm2. Macrofossils within the spherule bed represent a rich fauna of ammonites, benthic molluscs (bivalves and gastropods), echinoids, as well as crabs and sharks. Macrofossil preservation ranges from whole to fragmentary, with most fossils preserved as internal moulds. The infill of the fossils is lithologically identical to the matrix of the spherule bed, including impact ejecta preserved within phragmocones and body chambers of ammonites, and differs from the underlying Owl Creek Formation. This suggests that the animals were either alive or loosely scattered on the sea floor at the time of deposition. Grain size changes indicate multiple events were responsible for deposition, and together with taphonomic evidence are consistent with dynamic high energy post-impact processes. Later sea level change during the Paleocene is responsible for a sharp contact at the top of the spherule bed. Geochemical evidence from the Owl Creek and Clayton Formations at this locality indicate numerous local paleoenvironmental changes affected the Mississippi Embayment at the time of the K–Pg boundary and mass extinction event.Woiwode, U., Neubauer, S., Lindner, W., Buckenmaier, S., L?mmerhofer, M., 2018. Enantioselective multiple heartcut two-dimensional ultra-high-performance liquid chromatography method with a Coreshell chiral stationary phase in the second dimension for analysis of all proteinogenic amino acids in a single run. Journal of Chromatography A 1562, 69-77. multiple heartcut (MHC) 2D-UHPLC method with UV detection has been developed for the enantioselective analysis of complex amino acid mixtures in a single run. The MHC method is based on an achiral gradient RPLC separation with 1.8?μm C18 phase (100?×?2.1?mm ID column) in the first dimension (1D) and enantioselective isocratic separation on a tert-butylcarbamoylquinine-based 2.7?μm Coreshell particle column (50?×?3?mm ID) in the second dimension (2D). Pre-column derivatization has been performed with Sanger’s reagent (2,4-dinitrofluorobenzene) yielding chromogenic 2,4-dinitrophenylated amino acids (DNP-AAs). Heartcuts of 40?μL fractions of the 1D peaks were sampled into the 2D system via a two-position four-port dual valve connected to two loop decks each equipped with six 40?μL parking loops. Using this setup, 25 amino acids (20 proteinogenic plus allo-Thr, allo-Ile, homoserine (Hse), Orn, β-Ala) have been analyzed enantioselectively in a fully automated manner with a single chiral column within 130?min total run time (1D and 2D). All 2D separations together took 101.5?min (29 cuts with 3.5?min run time each) and thus the total analysis time was quite efficiently utilized. Faster separations were restricted by some software constraints which did not allow to adjust run times in 2D individually. The practical utility of this enantioselective MHC method is documented by application for the absolute configuration determination of the amino acids in gramicidin and bacitracin. Further optimizations should lead to a generic enantioselective amino acid analyzer for the quality control of synthetic peptides and the structural characterization of non-ribosomal peptides.Wojtacha-Rychter, K., Smoliński, A., 2018. Multi-component gas mixture transport through porous structure of coal. Fuel 233, 37-44. study of gas flow through porous coals is significantly important for the accurate assessment of the state of endogenous fire risk. Coal characterizes of a unique pore structure which provides a good storage capacity and an ideal transport pathway for the movement of gases. Gaseous products released from the source of coal self-heating flow through coal and may be subject to adsorption. In this study, the effects of the transport of multi-component gas mixture through a sorption column filled with granular coal and inert material were investigated. The experiment with coal presented in the paper proved that gas concentrations at the inlet (Co) and at the outlet of the sorption column (Ck) varied depending on the properties of coal and gas molecules. Based on the results, an index demonstrating the relationship between these concentrations was calculated. The experiment of gas mixture flow through inert material confirmed that the lowest index, i.e. below 0.7, obtained for propylene and acetylene in the experiment with coal was a result of sorption processes. Gases with lowest critical temperatures, such as carbon monoxide and hydrogen had the highest index which was above 0.9.Wood, R., Bowyer, F., Penny, A., Poulton, S.W., 2018. Did anoxia terminate Ediacaran benthic communities? Evidence from early diagenesis. Precambrian Research 313, 134-147. Ediacaran oceanic redox landscape was heterogeneous, where many basins had a shallow and highly dynamic chemocline above anoxic (ferruginous or euxinic) or low oxygen (manganous) waters. Seawater mMg/Ca ratio was also high, promoting early diagenetic dolomitisation. How the benthos responded to these conditions is fundamental to understanding their ecological dynamics. Here we utilise redox sensitive elements in early marine carbonate cements to investigate possible water column redox controls on the distribution and growth of the oldest metazoan communities.Skeletal communities in the Zaris Sub-Basin of the Nama Group, Namibia (～550–547?Ma), grew in shallow waters where fine-grained carbonate sediment often shows evidence of early dolomitisation. Mid-ramp Cloudina reefs are composed of open, highly porous structures that formed multiple, successive assemblages. Each assemblage is terminated by thin (<1?mm), layers of dolomicrite sediment and dolomite cement. All dolomitic lithologies in the Nama Group analysed via Fe speciation suggest precipitation under anoxic ferruginous water column conditions.Reef cements show a paragenetic sequence from synsedimentary to early marine cement and final burial, which we infer were precipitated under dynamic redox conditions. First, acicular pseudomorphed aragonite cement formed under oxic conditions (low Fe and Mn). Next, the presence of iron-rich dolomicrite sediment, often associated with a recrystallised ferroan dolomite crust, suggests that originally aragonitic or calcitic sediment and a high-Mg precursor cement were preferentially dolomitised. Dolomitisation may have been enhanced either via upwelling of deeper water, anoxic, ferruginous seawater, or by later fluid remobilisation from adjacent shales. A following Mn-rich calcite cement is inferred to be early marine due to its inclusion-rich, fibrous form and well-preserved CL zonation. The final blocky cement precipitated under oxic conditions, probably during shallow burial.The cements likely record a general shallow to deeper water transect, from oxic shallow waters to low oxygen manganous waters, then to oxic, shallow burial conditions. We hypothesize that Cloudina reef communities were terminated by episodic sediment incursions during short-term, transgressive cycles, possibly accompanied by upwelled, anoxic, ferruginous and dolomitising waters, although the timing for this is poorly constrained. More generally, such incursions may have terminated Ediacaran benthic communities that grew close to the chemocline.Worsley, H.K., O’Hara, S.J., 2018. Cross-species referential signalling events in domestic dogs (Canis familiaris). Animal Cognition 21, 457-465. gestures are used by a signaller to draw a recipient’s attention to a specific object, individual or event in the environment. These gestures have received much research attention in relation to human and non-human primates with great apes being shown to possess impressive gestural repertoires. Domestic dogs (Canis familiaris) meanwhile provide an ideal non-primate candidate for investigating referential signalling due to their unique relationship with humans that centres on non-verbal communication with frequent interaction. Here we observed 37 pet dogs in their own homes. Owners recorded 242 videos containing 47 potential referential gesture events. We analysed those recordings to reveal evidence of 19 referential gestures performed by domestic dogs during everyday communicative bouts with humans, showing that the gestures conform to the five features of referential signalling. Our study exposes impressive gesturing abilities in a non-primate mammal; especially when viewed in the context of the cross-species rather than intraspecific communication.Wu, B., Li, Y., Li, X., Zhu, J., Ma, R., Hu, S., 2018. Organochlorine compounds with a low boiling point in desalted crude oil: Identification and conversion. Energy & Fuels 32, 6475-6481. compounds (OOCs) with a low boiling point in desalted crude oil were identified via gas chromatography (GC) with electron capture detection (ECD), and the possibility of their hydrolysis was evaluated thermodynamically under the conditions of industrial distillation of desalted crude oil. Six fractions, namely, gasoline, aviation kerosene, light diesel, heavy diesel, lubricating oil, and residual oil, were obtained via true boiling point distillation. Chlorine concentration results indicated that OOCs with low and high boiling points were concentrated in the gasoline fraction and residual oil, respectively. Qualitative and quantitative analyses of low-boiling-point OOCs, such as carbon tetrachloride, tetrachloroethylene, 1,1,1,3-tetrachloropropane, and 1,2,4-trichlorobenzenem were performed via GC–ECD. The four types of OOCs coexisted in the gasoline, aviation kerosene, and light diesel fractions. Thermodynamic analysis results indicated that the four types of OOCs could hydrolyze to form corrosive HCl during industrial distillation of desalted crude oil. High-temperature and low-pressure conditions will enhance the OOC hydrolysis.Wu, J., Fan, T., Gao, Z., Yin, X., Fan, X., Li, C., Yu, W., Li, C., Zhang, C., Zhang, J., Sun, X., 2018. A conceptual model to investigate the impact of diagenesis and residual bitumen on the characteristics of Ordovician carbonate cap rock from Tarim Basin, China. Journal of Petroleum Science and Engineering 168, 226-245. Lower-Middle Ordovician Yingshan (O1-2y) Formation associated with large unconformity weathering crust was the main hydrocarbon reservoir in the Tarim Basin, and the dense limestone/dolomite within this formation was revealed as the local carbonate cap rock. Based on petrophysical properties, thin sections, cathodeluminescence (CL) and scanning electron microscope (SEM) measurements, the effects of cap rock on depositional settings, diagenesis and pyrobitumen were carefully analyzed. Carbonate cap rock dominated by micrite has ultralow porosity and permeability, with an average porosity of 0.568% and permeability of 0.07?×?10?3?μm2. There is a significant bottom-up thickness variation (from several to tens of meters) in different members within the O1-2y formation. The steady cap rock is more likely to be distributed in low-energy depositional environments, corresponding to intershoal sea, low-lying land of open platform and lagoon of restricted platform. Constructive diagenesis processes mainly comprise extreme filling, compaction and cementation, resulting in a significant decrease in the quantity and size of pores. Conversely, leaching and paleokarst dissolution, together with diagenesis associated with hydrothermal fluids, has a detrimental effect on the effective preservation of cap rock. Three types were summarized to characterize the cementation-compaction relationship between cement distribution and intraclast deformation. The increase in intraclast size indicate that the intergranular pores are likely to be cemented. A good sealing impact on the underlying oil-gas is confirmed in sparry calcarenite when its cement content reaches 15% and higher by volume. Early compaction vs. early cementation processes probably affect the sealing capacity, so high quality cap rock is primarily presented while cementation precedes compaction. Highly abundant stylolites filled with residual bitumen and precipitated cements in the cap rock intervals consistently have low poroperm values, resulting in micropore occlusion and occlusion of the late hydrocarbon migration pathways, which can act as barriers for the upward migration of oil-gas. A conceptual model of the evolution feature of cap rock provides a plausible interpretation for better understanding of the spatial distribution of carbonate cap rock in future exploration and development.Wu, T., Xu, J., Xie, W., Yao, Z., Yang, H., Sun, C., Li, X., 2018. Pseudomonas aeruginosa L10: A hydrocarbon-degrading, biosurfactant-producing, and plant-growth-promoting endophytic bacterium isolated from a reed (Phragmites australis). Frontiers in Microbiology 9, 1087. doi: 1010.3389/fmicb.2018.01087. endophytes with the capacity to degrade petroleum hydrocarbons and promote plant growth may facilitate phytoremediation for the removal of petroleum hydrocarbons from contaminated soils. A hydrocarbon-degrading, biosurfactant-producing, and plant-growth-promoting endophytic bacterium, Pseudomonas aeruginosa L10, was isolated from the roots of a reed, Phragmites australis, in the Yellow River Delta, Shandong, China. P. aeruginosa L10 efficiently degraded C10–C26 n-alkanes from diesel oil, as well as common polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, phenanthrene, and pyrene. In addition, P. aeruginosa L10 could produce biosurfactant, which was confirmed by the oil spreading method, and surface tension determination of inocula. Moreover, P. aeruginosa L10 had plant growth-stimulating attributes, including siderophore and indole-3-acetic acid (IAA) release, along with 1-aminocyclopropane-1-carboxylic (ACC) deaminase activity. To explore the mechanisms underlying the phenotypic traits of endophytic P. aeruginosa L10, we sequenced its complete genome. From the genome, we identified genes related to petroleum hydrocarbon degradation, such as putative genes encoding monooxygenase, dioxygenase, alcohol dehydrogenase, and aldehyde dehydrogenase. Genome annotation revealed that P. aeruginosa L10 contained a gene cluster involved in the biosynthesis of rhamnolipids, rhlABRI, which should be responsible for the observed biosurfactant activity. We also identified two clusters of genes involved in the biosynthesis of siderophore (pvcABCD and pchABCDREFG). The genome also harbored tryptophan biosynthetic genes (trpAB, trpDC, trpE, trpF, and trpG) that are responsible for IAA synthesis. Moreover, the genome contained the ACC deaminase gene essential for ACC deaminase activity. This study will facilitate applications of endophytic P. aeruginosa L10 to phytoremediation by advancing the understanding of hydrocarbon degradation, biosurfactant synthesis, and mutualistic interactions between endophytes and host plants.Wu, Z., Liu, B., Escher, P., Kowalski, N., B?ttcher, M.E., 2018. Carbon diagenesis in different sedimentary environments of the subtropical Beibu Gulf, South China Sea. Journal of Marine Systems 186, 68-84. depositional environment in the subtropical Beibu Gulf area is highly complex, and the sediments accumulate under specific combinations of hydrodynamics, physiography and sediment sources. In the present study, six sedimentary gravity cores were collected from three different depositional zones of the Beibu Gulf. We measured the geochemical and carbon isotopic compositions of pore water and solid sediments to characterize the benthic early diagenesis of carbon. Our results indicate that marine organic matter is rapidly remineralized in delta deposits and the Central Beibu Gulf. Terrestrial organic matter, however, seem to be more important at the bottom of the Central and Northern Coastal Beibu Gulf, which probably formed in an estuarine or fluvial environment before the Holocene or Pleistocene transgression. Organic matter degradation via microbial sulfate reduction is the most important source for isotopically light DIC (dissolved inorganic carbon) added to the pore waters at most sites. In the Central Beibu Gulf, however, the carbon isotope signatures of DIC indicate an additional source of light carbon and pore water profiles exhibit a characteristic pattern reflecting the occurrence of the anaerobic oxidation of methane. Moreover, we find that the pore water δ13Cadded is greater than the δ13C of total organic carbon net loss in solid sediments in the zones with relatively strong current environments. This result hints that the frequent physical reworking and reoxidation of bottom deposits are likely key factors controlling carbon isotopic fractionation between the sedimentary organic carbon and DIC. Overall, our results further reveal that carbon sources and transformations in the sediments sensitively respond to changes in depositional conditions. Pore water modeling give strong hints for non-steady state processes impacting diagenesis at several sites.Wymore, A.S., Potter, J., Rodríguez‐Cardona, B., McDowell, W.H., 2018. Using in‐situ optical sensors to understand the biogeochemistry of dissolved organic matter across a stream network. Water Resources Research 54, 2949-2958. The advent of high?frequency in situ optical sensors provides new opportunities to study the biogeochemistry of dissolved organic matter (DOM) in aquatic ecosystems. We used fDOM (fluorescent dissolved organic matter) to examine the spatial and temporal variability in dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) across a heterogeneous stream network that varies in NO3- concentration. Across the ten study streams fDOM explained twice the variability in the concentration of DOC (r2=?0.82) compared to DON (r2=0.39), which suggests that the N-rich fraction of DOM is either more variable in its sources or more bioreactive than the more stable C?rich fraction. Among sites, DON molar fluorescence was approximately 3x more variable than DOC molar fluorescence and was correlated with changes in inorganic N, indicating that DON is both more variable in composition as well as highly responsive to changes in inorganic N. Laboratory results also indicate that the fDOM sensors we used perform as well as the excitation?emission wavelength pair generally referred to as the "tryptophan-like" peak when measured under laboratory conditions. However, since neither the field sensor not the laboratory measurements explained a large percentage of variation in DON concentrations, challenges still remain for monitoring the ambient pool of dissolved organic nitrogen. Sensor networks provide new insights into the potential reactivity of DOM and the variability in DOC and DON biogeochemistry across sites. These insights are needed to build spatially explicit models describing organic matter dynamics and water quality.Xiang, L., Schoepfer, S.D., Zhang, H., Cao, C.-q., Shen, S.-z., 2018. Evolution of primary producers and productivity across the Ediacaran-Cambrian transition. Precambrian Research 313, 68-77. all extant animal phyla first appeared during the Ediacaran-Cambrian transition. A revolution in primary producer ecology and marine productivity has been proposed as a bottom-up ecological driver for this rapid diversification of metazoans. However, the control(s) driving the evolution of primary producers and primary productivity around the Ediacaran-Cambrian transition, and their potential relationship to the Cambrian Explosion, are not fully understood. In this study, we measured the nitrogen content and the nitrogen isotopic composition of kerogen in the Piyuancun and Hetang Formations, using samples collected from the Chunye-1 well, on the Lower Yangtze Block in western Zhejiang. Our isotope results suggest that nitrate was the dominant N source fueling primary productivity during deposition of the entire Piyuancun Formation and lower Hetang Formation, with only a minor contribution from N2 fixation. Quantitative reconstructions of paleoproductivity based on organic carbon and pyrite content and sedimentation rate indicate that productivity either stayed the same or increased during the transition from the Piyuancun Formation to the overlying Hetang Formation. Thus, fixed N availability was not the ultimate factor limiting primary productivity during the Ediacaran-Cambrian transition. Combining our data with published nitrogen isotope records from the Early-Middle Ediacaran to Cambrian Stage 4 suggests that NO3? was the dominant N species fueling phytoplanktonic productivity during the broad Cambrian Explosion interval, from its earliest roots in the Ediacaran through the main episode in Cambrian Stage 3. Eukaryotes lack the ability to fix nitrogen, and preferentially assimilate nitrate. The NO3?-dominated euphotic zone from the Early-Middle Ediacaran to Cambrian Stage 3 may have promoted the radiation of relatively large eukaryote phytoplankton, which may have been an important driver of early animal diversification.Xiao, Z., Tan, J., Ju, Y., Hilton, J., Yang, R., Zhou, P., Huang, Y., Ning, B., Liu, J., 2018. Natural gas potential of Carboniferous and Permian transitional shales in central Hunan, South China. Journal of Natural Gas Science and Engineering 55, 520-533. Carboniferous Ceshui formation and Permian Longtan and Dalong formations were deposited in transitional settings preserved in what is now central Hunan Province, South China, as they are potential natural gas plays. In this study, we analysed the total organic carbon (TOC), vitrinite reflectance (Ro), kerogen type, mineralogy, porosity, permeability, and methane adsorption of representative shale samples from these rock units. Our results indicate that TOC content can be as high as 9.2%, with a mean (x?) of 3.5%. The Permian shale formations were deposited in more strongly reducing environments than the Carboniferous Ceshui shale. The kerogen composition of the Carboniferous Ceshui shale is dominated by Type III, while both of the Permian shales contain primarily Type II kerogens; Ro values range from 1.1% to 2.4% (x??=?1.6%). The organic matter in all the studied shales is in the wet gas window of thermal maturity and is relatively less mature than Lower Palaeozoic marine shales in south China. Mineral compositions are dominated by quartz (x??=?53.8%) and clay (x??=?35.6%), suggesting a high brittleness index. Porosity ranges from 0.5% to 14% (x??=?6.4%), while permeability varies from 0.0026 micro Darcy (mD) to 0.0640 mD (x??=?0.0130 mD). The gas adsorption capacity varies from 1.24 to 4.53?cm3/g (x??=?2.40?cm3/g). Relatively less mature shale samples (Ro<1.5%) have low methane adsorption capacities, regardless of their TOC values. However, the methane adsorption capacity of more mature (Ro>1.5%) shales samples exhibit a positive correlation with TOC content.Xie, Q., Sari, A., Pu, W., Chen, Y., Brady, P.V., Al Maskari, N., Saeedi, A., 2018. pH effect on wettability of oil/brine/carbonate system: Implications for low salinity water flooding. Journal of Petroleum Science and Engineering 168, 419-425. of oil/brine/carbonate system is a critical parameter to govern subsurface multi-phase flow behaviour, thus remaining oil saturation and ultimate oil recovery in carbonate reservoirs. Despite the fact that salinity level, ionic strength, oil composition and rock chemistry (e.g., limestone and dolomite) have been extensively investigated, few work has been done regarding the effect of pH on oil/brine/rock interaction, thus wettability.We thereby measured contact angles at two different pH (pH?=?3 and 8) in the presence of either 1?mol/L Na2SO4 or 1?mol/L CaCl2 using a crude oil with acid number of 1.7 and base number of 1.2?mg KOH/g. Moreover, we performed a geochemical modelling study in light of the diffuse double layer to understand how pH controls the number of surface species at interfaces of oil/brine and brine/carbonate. Our results show that pH scales with oil/brine/carbonate wettability, demonstrating that pH is one of the controlling factors to govern the system wettability. Further, our results suggest that pH (6.5–7.5) likely triggers an oil-wet system, which is favourable for low salinity water flooding, but pH?<?5 usually exhibits a water-wet system, which explains why low salinity effect is not always observed in carbonate reservoirs. This also confirms that CO2 flooding, carbonated water flooding, and CO2 huff-and-puff EOR very likely renders a strongly water-wet system due to H+ adsorption on the interface of oil/brine and brine/carbonate as a result of CO2 dissolution.Xing, Y., Wang, M., Li, T., Yin, F., Wang, X., 2018. Determination of polycyclic aromatic hydrocarbons in water samples by gas chromatography coupled to triple quadrupole tandem mass spectrometry using macroporous resin solid‐phase extraction. Journal of Separation Science 41, 2453-2460. method for the determination of 16 polycyclic aromatic hydrocarbons in water has been developed. First, we made a solid‐phase extraction column. After this, the parameters affecting the efficacy of the experimental method were optimized, including appropriate selection of a solid‐phase extraction column and cleanup conditions on columns. The separation was achieved by gas chromatography and detection with triple quadrupole tandem mass spectrometry. The method showed satisfactory linearity (R2 > 0.999) over the range assayed (0.01–1 μg/mL), and limits of quantification ranging from 0.0011 to 0.0199 μg/L. The recoveries ranged from 83 to 113%. The relative standard deviation is in the range 0.86–3.1%. The results indicated that this method had high selectivity and precision that was suitable for the simultaneous determination of 16 polycyclic aromatic hydrocarbons in water.Xu, C., Liu, C., Guo, P., Li, M., Huang, L., Zhao, Y., Pan., Y., Zhang, Y., 2018. Geochemical characteristics and their geological significance of intrasalt mudstones from the Paleogene Qianjiang Formation in the Qianjiang Graben, Jianghan Basin, China. Acta Sedimentologica Sinica 36, 617-629. characteristics of intrasalt mudstones have great implications for the sedimentary environment of saline source rocks and the conditions for the symbiotic formation of halite ore. In this paper, 15 mudstone samples collected continuously from the lower part of the 3rd member of Qianjiang Formation in the Qianjiang Sag of the Jianghan Basin have been analyzed for major, trace and rare earth elements, in order to obtain a better understanding of the paleosalinity, redox conditions and paleoclimatic background. The high Sr contents and Sr/Ba ratios, and also the presence of glauberite indicate high-salinity conditions with organic-rich mudstones deposited. The redox indexes of V/Cr, V/Ni, V/(V+Ni), δCe, Ce/La, δU and Ceanom and the alteration of some redox-sensitive trace elements such as V, U, Ni ,Zn and Cr suggest low oxygen contents in water and the existence of water delamination with anaerobic conditions. The chemical index of alteration, Mg/Ca ratios and core observation indicate a semi-humid climate for source rocks deposition and semi-arid one for halite formation. The frequent variations of source rocks and halite deposits may indicate a fluctuated climate, probably corresponding well to the late Eocene doubt house climate. The inter-salt mudstones have a great potential to form high-quality source rocks. On the one hand, along with the alternatives of water freshening and salinizing due to climatic fluctuations, short pulses of feast and famine for living beings are conductive to the formation and accumulation of organic matters. On the other hand, deep-water and anoxic conditions during the humid pulse provide an appropriate environment to preserve organic matters.Xu, C., Zou, W., Yang, Y., Duan, Y., Shen, Y., Luo, B., Ni, C., Fu, X., Zhang, J., 2018. Status and prospects of deep oil and gas resources exploration and development onshore China. Journal of Natural Gas Geoscience 3, 11-24. significant breakthroughs have been made in regards to deep oil and gas exploration and development in recent years. However, a systematic analysis has not been carried out on the progress, challenges, and development trend of exploration and development of onshore deep oil and gas resources in China. This paper summarizes five main points of deep oil and gas resources: (1) more gas, less oil, and complicated phases; (2) high temperature and pressure, as well as profoundly different basins or formations; (3) multiple hydrocarbon sources and accumulations; (4) relatively tight but effective large-scale reservoirs; and (5) complicated accumulation process and multi-stage reconstructions. Based on the exploration and development history of deep oil and gas, this paper points out China's take on it is at the “large-scale discovery stage during which significant achievements have been obtained in carbonate, clastic, and volcanic reservoirs. Nonetheless, there are still four challenges, namely: (1) complex hydrocarbon generation, reservoir evolution, and accumulation restriction on how to determine exploration orientation and targets; (2) long well drilling and completion period, as well as high well construction cost delay petroleum discovery and efficient development; (3) undeveloped logging technology for HPHT slim holes that cannot ensure accurate identification of hydrocarbon reservoir; and (4) effective development and large-scale utilization of unspecific recovery technique and equipment limit. Finally, by the comprehensive analysis, it is concluded that onshore deep oil and gas resources are mainly distributed in three areas of six basins in China. The?areas have a vast exploration potential and have strategically successive resources. It is suggested that petroleum companies and universities, as well as research institutes, should work together to overcome difficulties in theory and practical technology for deep oil and gas exploration and development. Such partnership could develop fit-for-purpose theories and technical systems to support deep oil and gas development.Xu, D., Chai, M., Dong, Z., Rahman, M.M., Yu, X., Cai, J., 2018. Kinetic compensation effect in logistic distributed activation energy model for lignocellulosic biomass pyrolysis. Bioresource Technology 265, 139-145. kinetic compensation effect in the logistic distributed activation energy model (DAEM) for lignocellulosic biomass pyrolysis was investigated. The sum of square error (SSE) surface tool was used to analyze two theoretically simulated logistic DAEM processes for cellulose and xylan pyrolysis. The logistic DAEM coupled with the pattern search method for parameter estimation was used to analyze the experimental data of cellulose pyrolysis. The results showed that many parameter sets of the logistic DAEM could fit the data at different heating rates very well for both simulated and experimental processes, and a perfect linear relationship between the logarithm of the frequency factor and the mean value of the activation energy distribution was found. The parameters of the logistic DAEM can be estimated by coupling the optimization method and isoconversional kinetic methods. The results would be helpful for chemical kinetic analysis using DAEM.Xu, F., Yuan, H., Xu, G., Luo, X., 2018. Fluid charging and hydrocarbon accumulation in the Cambrian Longwangmiao Formation of Moxi Structure, Sichuan Basin, SW China. Petroleum Exploration and Development 45, 442-451. multi-stage minerals filled in pore space were sequenced, and the charging stages of fluid and hydrocarbon were reconstructed based on the observation of drilling cores and thin sections, homogeneous temperature testing of fluid inclusions, Laser Raman composition analysis and isotope geochemical analysis. The Cambrian Longwangmiao Formation in the study area went through 5 stages of fluid charging, in which 3 stages, mid-late Triassic, early-mid Jurassic and early-mid Cretaceous, were related to oil and gas charging. Especially the oil and gas charging event in early-mid Cretaceous was the critical period of gas accumulation in the study area, and was recorded by methane gas inclusions in the late stage quartz fillings. The 40Ar-39Ar dating of the 3rd stage methane inclusions shows that the natural gas charging of this stage was from 125.8±8.2 Ma. Analysis of Si, O isotopes and 87Sr/86Sr of the late stage quartz indicates that the fluid source of the quartz was formation water coming from long term evolution and concentration of meteoric water, but not from deep part or other sources, this also reflects that, in the critical charging period of natural gas, the Cambrian Longwangmiao Formation in Moxi structure had favorable conservation conditions for hydrocarbon accumulation, which was favorable for the formation of the Longwangmiao large natural gas pool.Xu, H., Xu, M., Li, Y., Liu, X., Guo, L., Jiang, H., 2018. Characterization, origin and aggregation behavior of colloids in eutrophic shallow lake. Water Research 142, 176-186. of colloidal particles contributes to the turbidity in the water column, which significantly influences water quality and ecological functions in aquatic environments especially shallow lakes. Here we report characterization, origin and aggregation behavior of aquatic colloids, including natural colloidal particles (NCPs) and total inorganic colloidal particles (TICPs), in a highly turbid shallow lake, via field observations, simulation experiments, ultrafiltration, spectral and microscopic, and light scattering techniques. The colloidal particles were characterized with various shapes (spherical, polygonal and elliptical) and aluminum-, silicon-, and ferric-containing mineralogical structures, with a size range of 20–200?nm. The process of sediment re-suspension under environmentally relevant conditions contributed 78–80% of TICPs and 54–55% of NCPs in Lake Taihu, representing an important source of colloids in the water column. Both mono- and divalent electrolytes enhanced colloidal aggregation, while a reverse trend was observed in the presence of natural organic matter (NOM). The influence of NOM on colloidal stability was highly related to molecular weight (MW) properties with the high MW fraction exhibiting higher stability efficiency than the low MW counterparts. However, the MW-dependent aggregation behavior for NCPs was less significant than that for TICPs, implying that previous results on colloidal behavior using model inorganic colloids alone should be reevaluated. Further studies are needed to better understand the mobility/stability and transformation of aquatic colloids and their role in governing the fate and transport of pollutants in natural waters.Xu, Q., Qiu, N., Liu, W., Shen, A., Wang, X., 2018. Thermal evolution and maturation of Sinian and Cambrian source rocks in the central Sichuan Basin, Southwest China. Journal of Asian Earth Sciences 164, 143-158. Sichuan Basin is among the basins with the most abundant oil and gas resources in China. The Sinian and Cambrian strata are the most important source rocks. Previous studies of the thermal history of the central Sichuan Basin have focused on the Late Paleozoic and studies of the Early Paleozoic thermal history are not available in literature and the thermal evolution of the Sinian and Cambrian source rocks are yet to be examined. A new thermal history was reconstructed using integrated thermal indicators, including apatite and zircon (U-Th)/He, zircon fission tracks, and equivalent vitrinite reflectance. The modeled results indicated that the heat flow was relatively low (<65?mW/m2) from the Sinian to Early Permian. During the Middle-Late Permian, the heat flow reached a maximum value (75–100?mW/m2) which may have been controlled by the heating effect of the Emeishan mantle plume and crustal extension. Following the Triassic, the heat flow gradually decreased to its present value of 60–70?mW/m2. The maturity histories of the source rocks, modeled based on the new thermal histories, indicate that the Sinian and Cambrian source rocks were slowly maturing during the Early Paleozoic, underwent rapid maturation during the Mesozoic, and reached the dry-gas stage during the Late Cretaceous. These new data on the thermal history and source rock maturity histories of the central Sichuan Basin provide new insights to guide oil and gas exploration of the basin.Xu, T., Pi, Z., Song, F., Liu, S., Liu, Z., 2018. Benzophenone used as the photochemical reagent for pinpointing C=C locations in unsaturated lipids through shotgun and liquid chromatography-mass spectrometry approaches. Analytica Chimica Acta 1028, 32-44. lipids exhibit different physiological significances due to the different locations of the carbon–carbon double bond (C=C). Identifying lipid isomers with mass-based methods remains challenging. Xia's group has been successfully employed Paternò–Büchi (PB) reaction, a photochemical reaction with UV irradiation, coupled with tandem mass spectrometry (MS/MS) to identify and quantify unsaturated lipids in complex mixtures. However, the existing PB reagents possess certain demerits. In this regard, a new PB reagent that is compatible with various lipidomic analysis platforms must be screened. In this study, we comprehensively evaluated the conditions of the PB reaction and screened benzophenone as a new PB reagent. Benzophenone possesses unique advantages, such as a relative high PB yield; the PB products could be readily distinguished from the reacted lipids based on the added high molecular weight (182?Da); and the benzophenone does not affect the lipids appearance interval for reversed-phase column separation. Furthermore, we optimized the reaction conditions by using benzophenone as a PB reagent and summarized the molecular formulas of the diagnostic ions according to the fragment rules. The proposed PB method has been implemented in shotgun and LC–MS lipidomics. To our best knowledge, this work is the first to report the integrated PB reaction with LC–MS lipidomics for identification of lipid isomers.Xu, W., Zhang, Y., Cao, H., Sheng, Y., Li, H., Li, Y., Zhao, H., Gui, X., 2018. Metagenomic insights into the microbiota profiles and bioaugmentation mechanism of organics removal in coal gasification wastewater in an anaerobic/anoxic/oxic system by methanol. Bioresource Technology 264, 106-115. gasification wastewater is a typical high phenol-containing, toxic and refractory industrial wastewater. Here, lab-scale anaerobic-anoxic-oxic system was employed to treat real coal gasification wastewater, and methanol was added to oxic tank as the co-substrate to enhance the removal of refractory organic pollutants. The results showed that the average COD removal in oxic effluent increased from 24.9% to 36.0% by adding methanol, the total phenols concentration decreased from 54.4 to 44.9?mg/L. GC-MS analysis revealed that contents of phenolic components and polycyclic aromatic hydrocarbons (PAHs) were decreased compared to the control and their degradation intermediates were observed. Microbial community revealed that methanol increased the abundance of phenolics and PAHs degraders such as Comamonas, Burkholderia and Sphingopyxis. Moreover, functional analysis revealed the relative abundance of functional genes associated with toluene, benzoate and PAHs degradation pathways was higher than that of control based on KEGG database.Xu, Z., Xu, Y.J., 2018. Dissolved carbon transport in a river-lake continuum: A case study in a subtropical watershed, USA. Science of The Total Environment 643, 640-650. and lakes have been traditionally studied as separate entities for carbon transport. However, there is a gap in our knowledge of the connectivity of dissolved carbon in a river-lake continuum. In this study, we analyzed dissolved carbon along the Little River-Catahoula Lake in subtropical Louisiana, United States to assess carbon biogeochemistry in such a river-lake continuum. Monthly in-situ measurements and water sample collections were made at four locations during April 2015 to February 2016 to determine riverine carbon transport into and out of the lake. Results show that much of the dissolved inorganic carbon (DIC) in the river-lake continuum originated from 13C depleted sources with an average δ13CDIC of ?18.5‰. Significant decreases in DIC were found after the river passed through the lake (from 482 to 399?μmol?L?1), which was most prevalent when the lake was not affected by backwater flow from the downstream river. CO2 outgassing could be mainly responsible for the sink behavior of the lake for DIC. Dissolved organic carbon (DOC) in the studied watershed were mostly terrigenous with low δ13CDOC averaged at ?29.2‰. Significant, consistent decreases in DOC concentrations were found from the river to the lake inflow and then to the lake outflow. During the majority of the year, the lake reduced DOC concentrations from the river inflow water, but switched to functioning as a source of DOC during warmer, dryer conditions in September and October due to increased water residence time. Therefore, the lake functioned both as a sink and as a source for DOC.Xuan, Q., Hu, C., Yu, D., Wang, L., Zhou, Y., Zhao, X., Li, Q., Hou, X., Xu, G., 2018. Development of a high coverage pseudotargeted lipidomics method based on ultra-high performance liquid chromatography–mass spectrometry. Analytical Chemistry 90, 7608-7616. coverage is crucial in comprehensive lipidomics studies challenged by high diversity in lipid structures and wide dynamic range in lipid levels. Current state-of-the-art lipidomics technologies are mostly based on mass spectrometry (MS), including direct-infusion MS, chromatography-MS, and matrix-assisted laser desorption ionization (MALDI) imaging MS, each with its pros and cons. Due to the need or favorability for measurement of isomers and isobars, chromatography-MS is preferable for lipid profiling. The ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS)-based nontargeted lipidomics approach and UHPLC-tandem MS (UHPLC-MS/MS)-based targeted approach are two representative methodological platforms for chromatography-MS. In the present study, we developed a high coverage pseudotargeted lipidomics method combining the advantages of nontargeted and targeted lipidomics approaches. The high coverage of lipids was achieved by integration of the detected lipids derived from nontargeted UHPLC-HRMS lipidomics analysis of multiple matrices (e.g., plasma, cell, and tissue) and the predicted lipids speculated on the basis of the structure and chromatographic retention behavior of the known lipids. A total of 3377 targeted lipid ion pairs with over 7000 lipid molecular structures were defined. The pseudotargeted lipidomics method was well validated with satisfactory analytical characteristics in terms of linearity, precision, reproducibility, and recovery for lipidomics profiling. Importantly, it showed better repeatability and higher coverage of lipids than the nontargeted lipidomics method. The applicability of the developed pseudotargeted lipidomics method was testified in defining differential lipids related to diabetes. We believe that comprehensive lipidomics studies will benefit from the developed high coverage pseudotargeted lipidomics approach.Yan, C., Liu, H., Sheng, Y., Huang, X., Nie, M., Huang, Q., Baalousha, M., 2018. Fluorescence characterization of fractionated dissolved organic matter in the five tributaries of Poyang Lake, China. Science of The Total Environment 637-638, 1311-1320. of natural colloids is the key to understand pollutant fate and transport in the environment. The present study investigates the relationship between size and fluorescence properties of colloidal organic matter (COM) from five tributaries of Poyang Lake. Colloids were size-fractionated using cross-flow ultrafiltration and their fluorescence properties were measured by three-dimensional excitation-emission matrix fluorescence spectroscopy (3D-EEM). Parallel factor analysis (PARAFAC) and/or Self-organizing map (SOM) were applied to assess fluorescence properties as proxy indicators for the different size of colloids. PARAFAC analysis identified four fluorescence components including three humic-like components (C1-C3) and a protein-like component (C4). These four fluorescence components, and in particular the protein-like component, are primarily present in <1?kDa phase. For the colloidal fractions (1–10?kDa, 10–100?kDa, and 100?kDa–0.7?μm), the majority of fluorophores are associated with the smallest size fraction. SOM analysis demonstrated that relatively high fluorescence intensity and aromaticity occur primarily in <1?kDa phase, followed by 1–10?kDa colloids. Coupling PARAFAC and SOM facilitate the visualization and interpretation of the relationship between colloidal size and fluorescence properties with fewer input variables, shorter running time, higher reliability, and nondestructive results. Fluorescence indices analysis reveals that the smallest colloidal fraction (1–10?kDa) was dominated by higher humified and less autochthonous COM.Yan, G., Xing, Y., Wang, J., Zhang, Z., Xu, L., Han, S., Zhang, J., Dai, G., Wang, Q., 2018. Effects of winter snowpack and nitrogen addition on the soil microbial community in a temperate forest in northeastern China. Ecological Indicators 93, 602-611. (N) deposition and change of snowpack are two critical factors for soil microbial community in temperate forests. The responses of soil microbial community composition and diversity to snowpack changes and N deposition are rarely investigated in winter. Therefore, we conducted an experiment to detect the microbial responses to the different snowpack depths (0?cm and 40?cm) and N addition (0?g?N?m?2?yr?1 and 5?g?N?m?2?yr?1 for four years) in a cold temperate forest in northeastern China in winter. The results indicated that decreased snowpack and increased N caused the significant changes in the soil microbial community composition in winter. The N addition significantly decreased bacterial abundance and diversity, which may be caused by decrease of pH and increase of inorganic N concentration under N addition. The decreased temperature associated with the removal of snowpack was considered to be able to trigger the variability in the soil fungal and bacterial community composition and diversity. The reduction in snowpack also decreased the soil respiration rate and the microbial biomass carbon (C) and N. However, the inhibition effect of N addition on soil respiration only occurred in the no snowpack treatments during the winter in our study, which indicates that N addition might change the activity of cold-tolerant microorganisms. In general, increased N deposition and reduced snowpack might potentially affect ecosystem functioning and terrestrial ecosystem C cycling in temperate forests under global change scenarios.Yan, J., Holzer, S., Pellegrini, L., Bell, S.D., 2018. An archaeal primase functions as a nanoscale caliper to define primer length. Proceedings of the National Academy of Sciences 115, 6697-6702.. The first phosphodiester linkage made during DNA replication is in the context of a short RNA primer synthesized by the dedicated RNA polymerase, primase. Primase, after synthesizing a defined short oligoribonucleotide, then transfers this primer to a DNA polymerase for extension. The mechanisms by which primer length is constrained remain elusive. Here, we dissect the basis of “counting” by an archaeal primase and propose a caliper-like mechanism to account for length determination.Abstract. The cellular replicative DNA polymerases cannot initiate DNA synthesis without a priming 3′ OH. During DNA replication, this is supplied in the context of a short RNA primer molecule synthesized by DNA primase. The primase of archaea and eukaryotes, despite having varying subunit compositions, share sequence and structural homology. Intriguingly, archaeal primase has been demonstrated to possess the ability to synthesize DNA de novo, a property shared with the eukaryotic PrimPol enzymes. The dual RNA and DNA synthetic capabilities of the archaeal DNA primase have led to the proposal that there may be a sequential hand-off between these synthetic modes of primase. In the current work, we dissect the functional interplay between DNA and RNA synthetic modes of primase. In addition, we determine the key determinants that govern primer length definition by the archaeal primase. Our results indicate a primer measuring system that functions akin to a caliper.Yan, K., Li, X., Chen, Z., Xu, C., Zhang, Y., Xia, Z., 2018. The formation of CH4 hydrate in the slit nanopore between the smectite basal surfaces by molecular dynamics simulation. Energy & Fuels 32, 6467-6474. gas hydrate (NGH) formation behavior in porous sediment influences the investigation of the reservoirs and the exploitation of NGH. However, its molecular mechanisms of NGH formation in the porous sediment remain unclear. In this work, we present the CH4 hydrate formation in the smectite system through molecular dynamics simulation. The microstructure molecular configurations and properties are analyzed. The results find the pure H2O solution and the CH4-H2O homogeneous solution in the initial configuration of the smectite layer reveal the different influence on the hydrate formation. The gas–water ratio (ri) affects the molecular diffusion and the hydrate formation. In the smectite layer, the two types of arrangements of cages are present: the semi-cage arrangement and the link-cage arrangement. The silicon-oxygen ring of the smectite surface connecting with the two types of arrangements of cages has the stable effect for the hydrate formation in the smectite.Yan, Z., Ferry, J.G., 2018. Electron bifurcation and confurcation in methanogenesis and reverse methanogenesis. Frontiers in Microbiology 9, 1322. doi: 1310.3389/fmicb.2018.01322. of the disulfide of coenzyme M and coenzyme B (CoMS–SCoB) by heterodisulfide reductases (HdrED and HdrABC) is the final step in all methanogenic pathways. Flavin-based electron bifurcation (FBEB) by soluble HdrABC homologs play additional roles in driving essential endergonic reactions at the expense of the exergonic reduction of CoMS–SCoM. In the first step of the CO2 reduction pathway, HdrABC complexed with hydrogenase or formate dehydrogenase generates reduced ferredoxin (Fdx2-) for the endergonic reduction of CO2 coupled to the exergonic reduction of CoMS–SCoB dependent on FBEB of electrons from H2 or formate. Roles for HdrABC:hydrogenase complexes are also proposed for pathways wherein the methyl group of methanol is reduced to methane with electrons from H2. The HdrABC complexes catalyze FBEB-dependent oxidation of H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS–SCoB. The Fdx2- supplies electrons for reduction of the methyl group to methane. In H2- independent pathways, three-fourths of the methyl groups are oxidized producing Fdx2- and reduced coenzyme F420 (F420H2). The F420H2 donates electrons for reduction of the remaining methyl groups to methane requiring transfer of electrons from Fdx2- to F420. HdrA1B1C1 is proposed to catalyze FBEB-dependent oxidation of Fdx2- for the endergonic reduction of F420 driven by the exergonic reduction of CoMS–SCoB. In H2- independent acetotrophic pathways, the methyl group of acetate is reduced to methane with electrons derived from oxidation of the carbonyl group mediated by Fdx. Electron transport involves a membrane-bound complex (Rnf) that oxidizes Fdx2- and generates a Na+ gradient driving ATP synthesis. It is postulated that F420 is reduced by Rnf requiring HdrA2B2C2 catalyzing FBEB-dependent oxidation of F420H2 for the endergonic reduction of Fdx driven by the exergonic reduction of CoMS–SCoB. The Fdx2- is recycled by Rnf and HdrA2B2C2 thereby conserving energy. The HdrA2B2C2 is also proposed to play a role in Fe(III)-dependent reverse methanogenesis. A flavin-based electron confurcating (FBEC) HdrABC complex is proposed for nitrate-dependent reverse methanogenesis in which the oxidation of CoM-SH/CoB-SH and Fdx2- is coupled to reduction of F420. The F420H2 donates electrons to a membrane complex that generates a proton gradient driving ATP synthesis.Yang, J., Zhan, C., Li, Y., Zhou, D., Yu, Y., Yu, J., 2018. Effect of salinity on soil respiration in relation to dissolved organic carbon and microbial characteristics of a wetland in the Liaohe River estuary, Northeast China. Science of The Total Environment 642, 946-953. salinity has important impacts on biogeochemical processes in estuary wetlands, with the potential to influence the soil respiration, dissolved organic carbon (DOC) and microbial population. However, it is unclear how soil respiration is related to changes in the DOC and microbial community composition with increasing salinity. In this study, soil cores were sampled from a brackish wetland in the Liaohe River estuary and treated by salinity solutions at four levels (fresh water, 3‰, 5‰, and 10‰). Samples of gas, water and soil were collected to determine the respiration rates and microbial community structure of the soil and the DOC leaching from the soil. Compared to the low-salinity treatments (fresh water and 3‰), the high-salinity treatments (5‰ and 10‰) decreased the soil respiration rates by 45–57% and decreased the DOC concentrations by 47–55%. However, no significant differences were observed within the low-salinity treatments nor the high-salinity treatments. There is a positive correlation between the soil respiration rates and DOC concentrations in all treatments, but it does not indicate a genetic cause-effect relationship between them. The microbial community structure varied with the salinity level, with higher β- and δ-Proteobacteria abundance, as well as higher Anaerolineae, and lower Clostridia abundance in the high-salinity treatments. The respiration rates were slightly negatively related to the richness of Proteobacteria and positively related to the richness of Clostridia. This study suggests that there may be a salinity threshold (3–10‰) impacting the organic carbon loss from estuarine brackish wetlands. In addition, the response of soil respiration to increasing salinity may be mainly linked to changes in the microbial community composition rather than changes in the DOC quantity.Yang, P., Bai, L., Wang, W., Rabasco, J., 2018. Analysis of hydrophobically modified ethylene oxide urethane rheology modifiers by comprehensive two dimensional liquid chromatography. Journal of Chromatography A 1560, 55-62. modified ethylene oxide urethane (HEUR) rheology modifiers are polymers used widely in waterborne coatings and other consumer products. The incorporation of hydrophobic end-groups significantly affects the thickening performance of HEURs. Therefore, understanding the degree of incorporation of hydrophobic end-groups on the polymer chain can help gain important insights on the structure/property relationship for HEUR rheology modifiers. A comprehensive two-dimensional liquid chromatography (2D-LC) method was developed for separating polymeric HEUR rheology modifiers based on the number of hydrophobic end-groups incorporated on the polymer chain. Our 2D-LC method uses a size exclusion chromatography (SEC) separation in the first dimension (1D) using an ultra-high performance Advance Polymer Chromatography (APC) column and a gradient reversed-phase liquid chromatography (RPLC) separation in the second dimension (2D). A low flow rate was used in the first dimension SEC separation to minimize the strong organic eluent transferred to the second dimension LC column. A small inner diameter (ID) LC column was used for the second dimension to reduce the total solvent consumption for routine analysis of process samples. The 1D flow rate, 2D transfer volume and gradient profile were all optimized to avoid polymer breakthrough and to achieve optimal separation of the polymer chains based on end-groups. Three types of polymer chains with 0, 1, and 2 terminal hydrophobes were successfully separated using this method. The total run time was further reduced by implementing flow programing in the first dimension separation. The 2D-LC method was applied to study how the polymerization process recipes affected hydrophobe incorporation and how the hydrophobe incorporation correlated with thickening efficiency. The method was also used to separate HEUR rheology modifier with branched polymer architecture.Yang, T.-B., Yan, P., He, M., Hong, L., Pei, R., Zhang, Z.-M., Yi, L.-Z., Yuan, X.-Y., 2018. Application of Subwindow Factor Analysis and Mass Spectral information for accurate alignment of non-targeted metabolic profiling. Journal of Chromatography A 1563, 162-170. peak shifts may lead to an incorrect statistical result for nontargeted metabolomics profiling, such as classification and discrimination in pattern recognition. In the paper, a more accurate alignment algorithm is developed based on Subwindow Factor Analysis and Mass Spectral information (SFA-MS). Compared with other methods, this new algorithm aligns the peaks more accurately without changing their shapes, especially for the overlapping peak clusters. To begin, the Continuous Wavelet Transform with Haar wavelet as the mother wavelet (Haar CWT) is used to determine the position and width of peaks. On this basis, the candidate drift points are confirmed by Fast Fourier Transform (FFT) cross correlation. Furthermore, the MS fitting degree of the common components between the reference chromatogram and the raw chromatogram is determined by the Subwindow Factor Analysis (SFA). When the MS information between reference and raw peaks is identical, the corresponding moving points are the optimum shifts. It is remarkable that all the peaks are moved through linear interpolation in the non-peak parts, so that the aligned chromatograms remain unchanged. The SFA-MS algorithm was implemented in the Matlab language and is available as an open source package.Yang, T.-R., Sander, P.M., 2018. The origin of the bird's beak: new insights from dinosaur incubation periods. Biology Letters 14. toothless beak of modern birds was considered as an adaption for feeding ecology; however, several recent studies suggested that developmental factors are also responsible for the toothless beak. Neontological and palaeontological studies have progressively uncovered how birds evolved toothless beaks and suggested that the multiple occurrences of complete edentulism in non-avian dinosaurs were the result of selection for specialized diets. Although developmental biology and ecological factors are not mutually exclusive, the conventional hypothesis that ecological factors account for the toothless beak appears insufficient. A recent study on dinosaur incubation period using embryonic teeth posited that tooth formation rate limits developmental speed, constraining toothed dinosaur incubation to slow reptilian rates. We suggest that selection for tooth loss was a side effect of selection for fast embryo growth and thus shorter incubation. This observation would also explain the multiple occurrences of tooth loss and beaks in non-avian dinosaur taxa crownward of Tyrannosaurus. Whereas our hypothesis is an observation without any experimental supports, more studies of gene regulation of tooth formation in embryos would allow testing for the trade-off between incubation period and tooth development.Yang, Y., Li, M., Li, X.-Y., Gu, J.-D., 2018. Two identical copies of the hydrazine synthase gene clusters found in the genomes of anammox bacteria. International Biodeterioration & Biodegradation 132, 236-240. synthase (HZS), encoded by the hzsABC gene cluster, is the unique and irreplaceable enzyme for the anammox reaction in this group of bacteria. This gene is widely used as a functional gene biomarker to retrieve the diversity, abundance and activity of anammox bacteria in different ecological niches. Genomes of anammox bacteria are constantly acquired, but the copy number of hzsABC gene cluster in the genome of anammox bacteria remains unsettled. In this study, three high quality anammox bacterial genomes were acquired from metagenomic datasets of activated sludge samples containing anammox bacteria. Interestingly, the coverage of hzsABC gene cluster in all of the three genomes was approximately two folds, comparing to the coverage of the corresponding genomic bin. However, only one assembled scaffold contained the full length of hzsABC in each genome, therefore it is likely that two identical copies of the hzsABC gene cluster are present in each of the three genomes. To confirm this, specific PCR primers were designed based on the assembled scaffolds containing the full-length hzsABC and partial hzsC genes. Two complete sequences connecting with the 5’ terminal of hzsC were successfully amplified using genomic DNA as templates, which further supported our hypothesis of the two identical copies of the gene. Moreover, the twofold coverage relationships of hzs genes and genomes were also found in the published genomes of“Ca. Brocadia sinica”, “Ca. Brocadia_caroliniensis”, “Ca. Brocadia_fulgida”. Overall, we would conclude that the genome of anammox bacteria contains two identical copies of hzsABC gene cluster, but functionality of the two identical genes needs further confirmations.Yao, G., Wu, X., Sun, Z., Yu, C., Ge, Y., Yang, X., Wen, L., Ni, C., Fu, X., Zhang, J., 2018. Status and prospects of exploration and exploitation key technologies of?the?deep petroleum resources in onshore China. Journal of Natural Gas Geoscience 3, 25-35. recent years, China's deep oil and gas exploration and exploitation have developed rapidly. Technological advancements have played an important role in the rapid exploration and highly efficient development. Aimed at the complex engineering geological environment of deep oil and gas in China, this paper has combined the four technological systems that have made significant progress, mainly including: (1) seismic imaging and reservoir prediction techniques for deep–burial complex structures, includign “2W1S” technique (wide-band, wide azimuth, and small bin), RTM (Reverse Time Migration), integrated modeling technology for complex structures and variable velocity mapping technique, improving structural interpretation accuracy, ensuring high precision ofimaging, and prediction for deep geological bodies; (2) deep speed raising and efficiency drilling technology series, which significantly improved the drilling speed, in turn reduced the drilling cost and drilling risk; (3) development of a deep high-temperature and high-pressure logging technology series, which provided a guarantee for the accurate identification of reservoir properties and fluid properties; (4) the efficient development technology for deep reservoirs, especially the development and maturity of the reconstruction volume technology, improve the production of single well and the benefit of deep oil and gas development. This paper further points out the improvement direction of the four major technology series of deep oil based on the analysis of the current development of the four major technological systems. Moreover, the development of applicability and economy for technical system is the key to realize high efficiency and low-cost exploration and development of deep oil and gas.Yaseen, S., Mansoori, G.A., 2018. Asphaltene aggregation due to waterflooding (A molecular dynamics study). Journal of Petroleum Science and Engineering 170, 177-183. the present study, we report our findings on various asphaltenes-water interactions at a high reservoir condition (550?K and 200?bar) and the role of water in asphaltene association during the waterflooding process. Molecular dynamics simulations are performed on oil/water and oil/brine systems. The oil phase is composed of asphaltenes (10?wt%) and ortho-xylene in which asphaltenes are entirely soluble. Seven different model-asphaltenes with diverse molecular weights, architectures, and heteroatom contents are employed. Interestingly, Results indicate that asphaltenes become less soluble in oil when water is partially misciblized in the oil phase. All model-asphaltenes containing nitrogen and/or oxygen atoms in their structures are prone to association. The driving force behind asphaltene aggregation is shown to be an asphaltene-water hydrogen bond. The utilization of the brine (3.5?wt% NaCl) instead of pure water induces a slight decrease in asphaltene propensity for aggregation due to salt-in effect. Results also suggest that face-to-face contact is the prominent stacking of asphaltene molecules in their aggregates.Yin, D.-M., Westerholm, M., Qiao, W., Bi, S.-J., Wandera, S.M., Fan, R., Jiang, M.-M., Dong, R.-J., 2018. An explanation of the methanogenic pathway for methane production in anaerobic digestion of nitrogen-rich materials under mesophilic and thermophilic conditions. Bioresource Technology 264, 42-50. impact of temperature on the anaerobic digestion of chicken manure was investigated by studying the process performance and pathway for continuously-fed digesters under mesophilic and thermophilic conditions. The mesophilic digester obtained a 15% higher methane yield compared with the thermophilic digester. Mesophilic and thermophilic digester had free ammonia of 31 and 145?mg/L, respectively. The stable carbon isotope analysis indicated that 41% and 50% of acetate was converted to methane through the syntrophic acetate oxidation and hydrogenotrophic methanogenesis (SAO-HM) pathway under mesophilic and thermophilic conditions, respectively. The genus Pseudomonas represented 10% and 16% under mesophilic and thermophilic conditions, respectively. A high abundance of the methanogens genus Methanoculleus (94% of total methanogens) in mesophilic and the genus Methanothermobacter (96%) in thermophilic digesters indicated they were the main hydrogenotrophic partners in SAO. The present study therefore illustrated that methanogenic pathway shifting, induced by free ammonia, closely correlated to the process performance.Yin, R., Kyle, J., Burnum-Johnson, K., Bloodsworth, K.J., Sussel, L., Ansong, C., Laskin, J., 2018. High spatial resolution imaging of mouse pancreatic islets using nanospray desorption electrospray ionization mass spectrometry. Analytical Chemistry 90, 6548-6555. Desorption Electrospray Ionization mass spectrometry imaging (nano-DESI MSI) enables ambient imaging of biological samples with high sensitivity and minimal sample pretreatment. Recently, we developed an approach for constant-distance mode MSI using shear force microscopy to precisely control the distance between the sample and the nano-DESI probe. Herein, we demonstrate the power of this approach for robust imaging of pancreatic islets with high spatial resolution of ～11 μm. Pancreatic islets are difficult to characterize using traditional mass spectrometry approaches due to their small size (～100 μm) and molecular heterogeneity. Nano-DESI MSI was used to examine the spatial localization of several lipid classes including phosphatidylcholine (PC), phosphatidylethanolamine (PE), sphingomyelin (SM), phosphatidylinositol (PI), and phosphatidylserine (PS) along with fatty acids and their metabolites (e.g., prostaglandins) in the individual islets and surrounding tissue. Several lipids were found to be substantially enhanced in the islets indicating these lipids may be involved in insulin secretion. Remarkably different distributions were observed for several pairs of Lyso PC (LPC) and PC species differing only by one double bond, such as LPC 18:1 vs LPC 18:0, PC 32:1 vs PC 32:0, and PC 34:2 vs PC 34:1. These findings indicate that minor variations in the fatty acid chain length and saturation have a pronounced effect on the localization of PC and LPC species in pancreatic islets. Interestingly, oxidized PC species observed experimentally were found to be specifically localized to pancreatic islets. These PCs are potential biomarkers for reactive oxygen species in the islets, which could be harmful to pancreatic beta cells. The experimental approach presented in this study will provide valuable information on the heterogeneity of individual pancreatic islets, which is difficult to assess using bulk characterization techniques.Yu, D., Rupasinghe, T.W.T., Boughton, B.A., Natera, S.H.A., Hill, C.B., Tarazona, P., Feussner, I., Roessner, U., 2018. A high-resolution HPLC-QqTOF platform using parallel reaction monitoring for in-depth lipid discovery and rapid profiling. Analytica Chimica Acta 1026, 87-100., we developed a robust lipidomics workflow merging both targeted and untargeted approaches on a single liquid chromatography coupled to quadrupole-time of flight (LC-QqTOF) mass spectrometry platform with parallel reaction monitoring (PRM). PRM assays integrate both untargeted profiling from MS1 scans and targeted profiling obtained from MS/MS data. This workflow enabled the discovery of more than 2300 unidentified features and identification of more than 600 lipid species from 23 lipid classes at the level of fatty acid/long chain base/sterol composition in a barley root extracts. We detected the presence of 142 glycosyl inositol phosphorylceramides (GIPC) with HN(Ac)-HA as the core structure of the polar head, 12 cardiolipins and 17 glucuronosyl diacylglycerols (GlcADG) which have been rarely reported previously for cereal crops. Using a scheduled algorithm with up to 100 precursors multiplexed per duty cycle, the PRM assay was able to achieve a rapid profiling of 291 species based on MS/MS data by a single injection. We used this novel approach to demonstrate the applicability and efficiency of the workflow to study salt stress induced changes in the barley root lipidome. Results show that 221 targeted lipids and 888 unknown features were found to have changed significantly in response to salt stress. This combined targeted and untargeted single workflow approach provides novel applications of lipidomics addressing biological questions.Yu, L., Xu, Y., Gong, Z., Huang, F., Zhang, L., Ren, S., 2018. Experimental study and numerical modeling of methane hydrate dissociation and gas invasion during drilling through hydrate bearing formations. Journal of Petroleum Science and Engineering 168, 507-520. hydrate has been concerned as a potential shallow hazard during deepwater drilling. In this study, hydrate dissociation and gas flow into wellbore induced by circulation of high temperature drilling fluid when drilling through hydrate bearing formations have been investigated. A specially designed experimental setup based on sandpack model was used, which can simulate the process of methane hydrate dissociation and gas production in wellbore with circulation of drilling fluid. The experimental results show that the rates of hydrate dissociation and gas production are greatly influenced by the temperature of drilling fluid, hydrate saturation and pressure. A mathematical model was derived to simulate the process of hydrate dissociation and gas invasion into wellbore within a few hours when hydrate zones being penetrated during drilling. The effects of various parameters on gas invasion rate have been evaluated, including the inlet temperature and circulation rate of drilling fluid, the rate of penetration, the wellbore size, and the circulation condition with or without drilling risers. The results show that small to moderate gas invasion can occur when drilling through hydrate zones mainly depending on the inlet temperature of drilling fluid and hydrate saturation in near wellbore formation, which can be manageable when low-temperature drilling fluid is used and with a low circulation rate. Optimizing penetration rate, reducing wellbore size and drilling without risers are also beneficial to decreasing the gas invasion from hydrate zones into the wellbore.Yu, T., Wu, W., Liang, W., Lever, M.A., Hinrichs, K.-U., Wang, F., 2018. Growth of sedimentary Bathyarchaeota on lignin as an energy source. Proceedings of the National Academy of Sciences 115, 6022-6027.: Marine sediment holds the largest organic carbon pool on earth, where microbial transformation of carbon is considered a key process of carbon cycling. Bathyarchaeota are among the most abundant and active groups of microorganisms in marine sediment. It has been suggested that Bathyarchaeota may play a globally important role in the carbon cycling in the marine environment through fermentation of complex organic substances, acetogenesis, and methanogenesis based on metagenome analysis. Here we provide several lines of converging evidence suggesting the bathyarchaeotal group Bathy-8 is able to grow with lignin as an energy source and bicarbonate as a carbon source. Consequently, members of the Bathyarchaeota are probably important, previously unrecognized degraders of lignin.Abstract: Members of the archaeal phylum Bathyarchaeota are among the most abundant microorganisms on Earth. Although versatile metabolic capabilities such as acetogenesis, methanogenesis, and fermentation have been suggested for bathyarchaeotal members, no direct confirmation of these metabolic functions has been achieved through growth of Bathyarchaeota in the laboratory. Here we demonstrate, on the basis of gene-copy numbers and probing of archaeal lipids, the growth of Bathyarchaeota subgroup Bathy-8 in enrichments of estuarine sediments with the biopolymer lignin. Other organic substrates (casein, oleic acid, cellulose, and phenol) did not significantly stimulate growth of Bathyarchaeota. Meanwhile, putative bathyarchaeotal tetraether lipids incorporated 13C from 13C-bicarbonate only when added in concert with lignin. Our results are consistent with organoautotrophic growth of a bathyarchaeotal group with lignin as an energy source and bicarbonate as a carbon source and shed light into the cycling of one of Earth’s most abundant biopolymers in anoxic marine sediment.Yu, X., Lee, K., Ma, B., Asiedu, E., Ulrich, A.C., 2018. Indigenous microorganisms residing in oil sands tailings biodegrade residual bitumen. Chemosphere 209, 551-559. purpose of this study was to determine the capacity of indigenous microbes in tailings to degrade bitumen aerobically, and if acetate biostimulation further improved degradation. Fluid fine tailings, from Base Mine Lake (BML), were used as microbial inocula, and bitumen in the tailings served as a potential carbon source during the experiment. The tailings were capped with 0.22?μm-filtered BML surface water with or without BML bitumen and acetate addition and incubated for 100 days at 20?°C. CO2 production and petroleum hydrocarbon reductions (50–70% for the biostimulation treatment) in the tailings were observed. DNA was extracted directly from the tailings, and increased bacterial density was observed by qPCR targeting the rpoB gene in the biostimulated group. 16?S rRNA sequencing was used to determine microbial composition profiles in each treatment group. The microbial communities indigenous to the tailings shifted after the bitumen was added. Acidovorax, Rhodoferax, Pseudomonas and Pseudoxanthomonas spp. significantly increased compared to the original microbial community and demonstrated tolerance to bitumen-based toxicity. The first three genera showed more potential for biostimulation treatment with acetate and may be important bitumen/hydrocarbon-degraders in an oil sands end pit lake environment.Yuan, X., Zhang, X., Chen, X., Kong, D., Liu, X., Shen, S., 2018. Synergistic degradation of crude oil by indigenous bacterial consortium and exogenous fungus Scedosporium boydii. Bioresource Technology 264, 190-197. purpose of this study was to investigate the potential of defined co-culture of indigenous bacterial consortium and exogenous fungus Scedosporium boydii for biodegradation of crude oil. After 7?days of incubation, residual oil, n-alkanes and aromatic fraction were analyzed. The degradation rate of crude oil was increased from 61.06% to 81.45% by the defined co-culture according to the 3:1 inoculation ratio of bacteria to fungi. The microbial activity was enhanced markedly and the formation of biofilms was accelerated after suitable inoculation of Scedosporium boydii. High throughput analysis showed that bacterial evenness and diversity were increased and the relative abundance of Paraburkholderia tropica was increased observably from 7.67% to 56.13% in the defined co-culture. These results indicated that synergistic degradation of crude oil in the bacteria-fungi consortium may be advantageous for bioremediation of petroleum-contaminated site.Yuan, Y., Rezaee, R., Verrall, M., Hu, S.-Y., Zou, J., Testmanti, N., 2018. Pore characterization and clay bound water assessment in shale with a combination of NMR and low-pressure nitrogen gas adsorption. International Journal of Coal Geology 194, 11-21. size distribution (PSD) and the volume of clay bound water (CBW) are crucial parameters for gas shale reservoirs formation evaluation. Low-field nuclear magnetic resonance (LF-NMR) has been extensively applied to characterize petrophysical properties of reservoirs. However, limited understanding remains for unconventional shales. Defining NMR T2 cutoff to differentiate CBW from free water is a challenge in shales since conventional approach, such as using centrifuge, is not feasible to completely remove free water in tight shales. Thermal treatment is therefore suggested for further extraction of movable pore water, however, the influence of temperature on nanoscale pore structure and clay mineralogical composition has been underestimated in previous studies and thus requires further investigation. This paper re-defines the critical dehydration temperature for accurate PSD interpretation in Permian Carynginia shale, Western Australia to determine T2 cutoff for CBW. By using low-pressure N2 gas adsorption (LP-N2-GA) in parallel with LF-NMR, we identified a striking anomalous PSD consistency for critical temperature detection and verification. Our results shows that movable pore water can be maximally removed around 80?°C (75?°C), while the sensitive clay, CBW and microstructure are well-preserved for accurate petrophysical evaluation. Clay mineral conversion would occur when temperatures are higher than 80?°C, while temperatures lower than 75?°C would induce large misinterpretations for nanopore structure. Our recommended scheme could provide a potential adaptability for the formation evaluation of Permian Carynginia shale in the downhole practices.Yurchenko, I.A., Moldowan, J.M., Peters, K.E., Magoon, L.B., Graham, S.A., 2018. The role of calcareous and shaly source rocks in the composition of petroleum expelled from the Triassic Shublik Formation, Alaska North Slope. Organic Geochemistry 122, 52-67. nearly thirty years, the Triassic marine carbonate Shublik Formation has been suggested and confirmed as a key source rock for hydrocarbons in the North Slope of Alaska. The formation accounts for roughly one third of the oil in the supergiant Prudhoe Bay Field, and for nearly all of the oil in the second largest Kuparuk River Field. Recent studies of oil types in the vicinity of the Northstar Field suggested presence of “shaly” organofacies of the Shublik Formation based on the likely Triassic age and marine shale biomarker signatures of some analyzed oil samples. The current work fills the gap between biomarker analysis of predicted “calcareous” and “shaly” oil types and source rock geochemistry. Biomarker-based oil-source rock correlation confirms the presence of two genetically-distinct organofacies and related oil families. Both groups were deposited under a similar redox condition (anoxic to suboxic) with dominantly marine algal input but in either (1) a clay-rich or (2) a clay-poor depositional setting. Chemometric evaluation of multivariate biomarker data reveals mixtures with variable degrees of mixing between end members. Analysis of diamondoids confirms mixed oil types and establishes diamondoid signatures of source rock end-members. This allows for correlation of biomarker-poor, overmature Shublik source rock samples to oils, and extends these interpretations over large areas of the North Slope.Zakharova, Y.R., Petrova, D.P., Galachyants, Y.P., Bashenkhaeva, M.V., Kurilkina, M.I., Likhoshway, Y.V., 2018. Bacterial and archaeal community structure in the surface diatom sediments of deep freshwater Lake Baikal (eastern Siberia). Geomicrobiology Journal 35, 635-647. sediment records of large lakes can be used to decipher the history of ancient phytoplankton. The upper layer of the sediment is an important area of remineralization of the sedimenting phytoplankton biomass. It hosts a bacterial community different from those of both the water column and deeper sediment layers. In this work, we analyzed the structure and diversity of the communities of Bacteria and Archaea in the surface sediment core containing valves of diatoms, the major producers in Lake Baikal. Pyrosequencing of the bacterial V3-V4 region of the 16 S ribosomal RNA (rRNA) and archaeal V1?V3 16 S rRNA gene regions yielded 29,168 and 36,997 reads, respectively. In total, we have identified 33 bacterial phyla; uncultured Actinobacteria were the most abundant in the upper layers, while lower sediment was dominated by Firmicutes and Alphaproteobacteria. The composition of the archaeal community changed with depth, but was generally dominated by Crenarchaeota from the classes Marine Group I and Miscellaneous Crenarchaeotic Group, as well as Euryarchaeota from the class Thermoplasmata. These dominant bacterial and archaeal taxa are presumed to participate in the destruction of buried organic matter, which eventually leads to degradation of the diatom valves.Zatoń, M., Nied?wiedzki, G., Rakociński, M., Blom, H., Kear, B.P., 2018. Earliest Triassic metazoan bioconstructions from East Greenland reveal a pioneering benthic community in the immediate aftermath of the end-Permian mass extinction. Global and Planetary Change 167, 87-98. benthic ecosystems collapsed during the catastrophic end-Permian mass extinction, and subsequently endured a protracted phase of biotic recovery under harsh environmental conditions. In particular, metazoan reef communities almost totally disappeared and were replaced by microbe-dominated mounds during the latest Permian–earliest Triassic. Here we report the stratigraphically oldest exclusively metazoan bioconstructions from earliest Triassic (mid-Induan) strata in East Greenland — these formed within the first ca 300?ka after the Permian-Triassic boundary. Unlike the multitaxic sponge-microbe and bivalve-based buildups recorded from the Early Triassic peri-paleoequatorial Panthalassan and Tethyan margins, the East Greenland bioaccumulations developed within a restricted Boreal mid-paleolatitude seaway, and comprised a monospecific primary framework of microconchid ‘lophophorate’ tubes with shell fragments and phosphatic debris cemented by biogenic calcite. Prostrate growth of the microconchids likely facilitated their accretion into successive sheet-like biostromes and small bioherms. These are associated with a regional paleoenvironmental shift towards well?oxygenated bottom waters, and locally punctuated sedimentation that created a favorable habitat. Although microconchids were both abundant and geographically widespread throughout the earliest Triassic, such buildups formed solely by these metazoans have not been reported from that time frame outside the Boreal Realm. These apparently flourished in the absence of more stable complex communities, and suggest that a locally variable, rather than ubiquitously sequential revival of metazoan bioconstruction activity took place in the immediate aftermath of the end-Permian extinction. However, these may also suggest that ecological recovery of benthic marine ecosystems following the end-Permian mass extinction might have started earlier in higher paleolatitudes.Zemskaya, T.I., Lomakina, A.V., Mamaeva, E.V., Zakharenko, A.S., Likhoshvai, A.V., Galach’yants, Y.P., Müller, B., 2018. Composition of microbial communities in sediments from southern Baikal containing Fe/Mn concretions. Microbiology 87, 382-392. parallel sequencing of the 16S rRNA gene fragments was used to investigate the composition and diversity of microbial communities in sediments from Southern Baikal to a depth of 9 cm with 1-cm step. In the layers from the sediment surface to the lower border of oxygen penetration (2 cm), organotrophic bacteria with high similarity to the heterotrophic species Luteolibacter luojiensis constituted the largest fraction of the community. In the formation zone of Fe/Mn crusts (3–5 cm), Proteobacteria and Actinobacteria predominated in the community, while the share of Cyanobacteria was considerable. The lower reduced layers showed an increased contribution of the Bacteroidetes, while the shares of the taxa predominant in the higher layers remained significant. Analysis of archaeal 16S rRNA gene amplicons revealed predominance of the soil and aquatic Thaumarchaeota (Marine Group I lineage), which are involved in anaerobic ammonium oxidation, practically in all sediment layers. The buried oxidized layer (6–7 cm), where members of the uncultured Marine Benthic Group D lineage of the order Thermoplasmatales (Euryarchaeota) predominated, was an exception in this regard. Small numbers of archaea of the Baikal-1 lineages (below 1%) were observed in the communities from the 6–7 and 7–8 cm layers, while the archaea involved in anaerobic methane oxidation (including the ANME-2d group) were not detected. Original Russian Text ? T.I. Zemskaya, A.V. Lomakina, E.V. Mamaeva, A.S. Zakharenko, A.V. Likhoshvai, Yu.P. Galach’yants, B. Müller, 2018, published in Mikrobiologiya, 2018, Vol. 87, No. 3.Zeng, Q., Chen, S., He, P., Yang, Q., Guo, X., Chen, P., Dai, C., Li, X., Gai, S., Deng, Y., Hou, H., 2018. Quantitative prediction of shale gas sweet spots based on seismic data in Lower Silurian Longmaxi Formation, Weiyuan area, Sichuan Basin, SW China. Petroleum Exploration and Development 45, 422-430. spots in the shale reservoirs of the Lower Silurian Longmaxi Formation in Weiyuan 201 Block of Sichuan Basin were predicted quantitatively using seismic data and fuzzy optimization method. First, based on seismic and rock physics analysis, the rock physics characteristics of the reservoirs were determined, and elastic parameters sensitive to shale reservoirs with high gas content were selected. Second, data volumes with high precision of the elastic parameters were obtained from pre-stack simultaneous inversion. The horizontal distribution of key parameters for shale gas evaluation were calculated based on the results of rock physics analysis. Then, the fuzzy evaluation equation was established by fuzzy optimization method with test and logging data of horizontal wells with similar operation conditions. key parameters affecting the productivity of horizontal wells were sorted out and the weights of them in the sweet spots quantitative prediction were worked out by fuzzy optimization to set up a sweet spots evaluation system. Three classes of shale gas reservoirs which including two kinds of sweet spots were predicted with the above procedure, and the sweet spots have been predicted quantitatively by combining the above prediction results with the testing production. The testing results of 7 verification wells proved the reliability of the prediction results.Zhang, B., Zheng, J., Yin, Z., Liu, C., Wu, Q., Wu, Q., Liu, C., Gao, X., Zhang, Q., 2018. Methane hydrate formation in mixed-size porous media with gas circulation: Effects of sediment properties on gas consumption, hydrate saturation and rate constant. Fuel 233, 94-102. a promising potential source for natural gas, methane hydrate (MH) is attracting increasing interest due to its great amount and diverse geographic distribution. The formation of MH is significantly influenced by the properties of sediment media such as porosity and permeability. In this study, in order to have a better understanding on the relationship between MH formation behavior and sediment properties, as well as to synthesize representative hydrate samples, MH was formed in six different sets of mixed-size porous media composed of clay, silt and fine sand, with saline water and circulating methane gas to reflect MH formation with free methane flux in marine sediment. The sediment composition, experimental pressure (15?MPa) and temperature (286.2?K) were chosen based on the SH2 drilling site in the Shenhu area in South China Sea. A two-stage growing behavior was observed for all systems. The gas consumption and hydrate formation rate exhibited positive relations with the permeability and porosity of the sediments. Furthermore, hydrates were found to be preferably formed in the bottom layer of the sediment, which could be attributed to the drastic drop of permeability at the early stage of hydrate formation. Lastly, the hydrate formation rate constant was calculated based on the intrinsic kinetic model and found to be a good reflection of the mass transfer properties of different porous media.Zhang, C., Chu, M., Chang, Z., Bai, S., Ma, L., Lin, H., 2018. Gravity separation of oil shale and low-temperature pyrolysis characteristics of different density fractions. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 40, 1315-1321. this paper, gravity separation of Huadian? (HD) and Longkou? (LK) oil shales and low-temperature pyrolysis characteristics of their different density fractions have been studied. The gravity separation results showed that kerogen could be enriched using the gravity separation method. The low-temperature pyrolysis results showed that the highest oil contents of HD and LK were in the density fractions of 1.4–1.5 and 1.5–1.6 g·cm?3, respectively. Meanwhile, for the low-temperature pyrolysis, the oil/gas ratio decreased with the density increase, indicating higher gas loss and lower oil yield with the increase of density. The mineralogical analysis showed that most of the organic matter were associated with clay minerals, and the organic matter could not fully liberate from the matrix under coarse particles. The migration and occurrence of minerals and organic matter in different density fractions generated various pyrolysis characteristics.Zhang, C., Wang, X., Zhu, L., 2018. Estimation of total porosity in shale formations from element capture logging and conventional logging data. Arabian Journal of Geosciences 11, 264. Herron model does not consider the effect of organic matter and gas on total porosity. In this paper, the shale rock is equivalent to three parts: skeleton, organic matter, and pore. According to the volume model, a new total porosity model is established. The new model is applied to estimate the total porosity of a shale gas well in South Sichuan area from element capture logging and conventional logging data. The results show that in the formations with high gas content and organic matter, the total porosity calculated by the new model is smaller than that calculated by the Herron model. To verify the accuracy of the new model in evaluating the total porosity of shale, the advantages and disadvantages of Gas Research Institute (GRI) measurement method and helium injection measurement method for determining porosity are discussed in terms of theoretical analysis and experimental measurement. It is considered that the GRI porosity is closer to the total porosity of shale and it can be used to test the total porosity of logging evaluation. The total porosity of the ten shale samples calculated by the new model and the Herron model is compared with the GRI porosity. Results show that the average relative errors calculated by the Herron model and the new model are 61 and 10%, respectively. It indicates that the accuracy of the total porosity calculated by the new model is higher.Zhang, F., Ma, G., Tao, Y., Liu, X., Liu, Y., Li, R., 2018. Characteristics of hydraulic fracture surface based on 3D scanning technology. Royal Society Open Science 5, Article 171845. surface characteristics of fractured specimens are important in hydraulic fracturing laboratory experiments. In this paper, we present a three-dimensional (3D) scanning device assembled to study these surface characteristics. Cube-shaped rock specimens were produced in the laboratory and subjected to triaxial loading until the specimen split in two in a hydraulic fracturing experiment. Each fractured specimen was placed on a rotating platform and scanned to produce 3D superficial coordinates of the surface of the fractured specimen. The scanned data were processed to produce high-precision digital images of the fractured model, a surface contour map and accurate values of the superficial area and specimen volume. The images produced by processing the 3D scanner data provided detailed information on the morphology of the fractured surface and mechanism of fracture propagation. High-precision 3D mapping of the fractured surfaces is essential for quantitative analysis of fractured specimens. The 3D scanning technology presented here is an important tool for the study of fracture characteristics in hydraulic fracturing experiments.Zhang, G., Ranjith, P.G., Perera, M.S.A., Haque, A., Choi, X., Sampath, K.S.M., 2018. Characterization of coal porosity and permeability evolution by demineralisation using image processing techniques: A micro-computed tomography study. Journal of Natural Gas Science and Engineering 56, 384-396. permeability of coal is the key parameter both in primary and enhanced coalbed methane recovery. The natural cleat system in coal serves as the primary pathway for gas flow in coal seams though mineralisation in cleats and is known to significantly reduce coal permeability. This paper reports on a numerical simulation of the pore network evolution of coal subject to cleat demineralisation. A high-resolution micro-computed tomography scanner was used to characterize the micro-structures of three anthracite coal samples. The mineral phases available in the coal samples were selectively removed to different extents (20%, 40%, 60%, 80% and 100%) and merged into the pore space using image processing techniques. In this way, the coal demineralisation process could be simulated and its impact on porosity and permeability studied. Comprehensive pore structure characterizations, including porosity, connectivity and tortuosity, were then conducted on the reconstructed pore network using Avizo software. Pore network models were also extracted to investigate changes in the pore and throat attributes. The lattice Boltzmann method was adopted to identify the absolute permeability changes with cleat demineralisation. The results reveal that demineralisation can increase coal porosity and permeability up to a percolation threshold. Although porosity was enhanced prior to the percolation threshold, the coal permeability was not enhanced due to poor pore connectivity. The permeability changed rapidly close to the percolation threshold, depending on the degree of demineralisation, and an exponential relation was observed between permeability and the amount of demineralisation. According to the observations, complete removal of the mineral phase can significantly increase the connected porosity while reducing the pore tortuosity, resulting in several orders of magnitude increase in coal permeability. This study shows that cleat demineralisation is an effective permeability enhancement technique for coalbed methane recovery, if very high demineralisation can be achieved.Zhang, H., Cao, L., 2018. Simulated effects of interactions between ocean acidification, marine organism calcification, and organic carbon export on ocean carbon and oxygen cycles. Science China Earth Sciences 61, 804-822. acidification caused by oceanic uptake of anthropogenic carbon dioxide (CO2) tends to suppress the calcification of some marine organisms. This reduced calcification then enhances surface ocean alkalinity and increases oceanic CO2 uptake, a process that is termed calcification feedback. On the other hand, decreased calcification also reduces the export flux of calcium carbonate (CaCO3), potentially reducing CaCO3-bound organic carbon export flux and CO2 uptake, a process that is termed ballast feedback. In this study, we incorporate a range of different parameterizations of the links between organic carbon export, calcification, and ocean acidification into an Earth system model, in order to quantify the long-term effects on oceanic CO2 uptake that result from calcification and ballast feedbacks. We utilize an intensive CO2 emission scenario to drive the model in which an estimated fossil fuel resource of 5000 Pg C is burnt out over the course of just a few centuries. Simulated results show that, in the absence of both calcification and ballast feedbacks, by year 3500, accumulated oceanic CO2 uptake is 2041 Pg C. Inclusion of calcification feedback alone increases the simulated uptake by 629 Pg C (31%), while the inclusion of both calcification and ballast feedbacks increase simulated uptake by 449–498 Pg C (22–24%), depending on the parameter values used in the ballast feedback scheme. These results indicate that ballast effect counteracts calcification effect in oceanic CO2 uptake. Ballast effect causes more organic carbon to accumulate and decompose in the upper ocean, which in turn leads to decreased oxygen concentration in the upper ocean and increased oxygen at depths. By year 2600, the inclusion of ballast effect would decrease oxygen concentration by 11% at depth of ca. 200 m in tropics. Our study highlights the potentially critical effects of interactions between ocean acidification, marine organism calcification, and CaCO3-bound organic carbon export on the ocean carbon and oxygen cycles.Zhang, H., Zhong, Y., She, J., Li, G., 2018. Characterization of shale matrix pore structure via experiment and model. Arabian Journal of Geosciences 11, Article 320. gas reservoirs develop multi-scale pores ranging in size from nanometer to micrometer, the characteristics of gas transport involve the multi-scale pore space which divided into organic and inorganic matrix pores. This paper reveals the shale pore structure with large amounts of organic mesoporous based on the techniques of focused ion beam scanning electron microscopes (FIB-SEM), high-pressure mercury intrusion (MICP), and low-pressure adsorption (LPA), which also shows the size and distribution of these pores. Then the research characterizes effective pore scale via circular tube bundle model with due regard for gas adsorption layer thickness on the walls of organic pores and water film thickness on the walls of inorganic pores, and the investigation of shale pore geometry is significant for designing and developing shale gas reservoirs. This work shows that the widely existing shale mesoporous volume with diameter of 2~50?nm accounts for 81% based on experimental testing, then it reduces to about 76% via effective diameter model calculation.Zhang, J., Li, X., Zhang, X., Zhang, M., Cong, G., Zhang, G., Wang, F., 2018. Geochemical and geological characterization of marine–continental transitional shales from Longtan Formation in Yangtze area, South China. Marine and Petroleum Geology 96, 1-15. previous research has provided useful insights into unconventional shale gas resources in recent years, the geochemical and geological characteristics of marine–continental transitional shale have not been studied systematically. During the Late Permian, Longtan Formation shales were widely deposited in the Yangtze area of South China. These shales clearly indicate the need to deepen our understanding of marine–continental transitional shales. This study describes the various characteristics of black shales from the Longtan Formation in this area on the basis of a field investigation and relevant laboratory analyses. Longtan shale reservoirs, with a thickness and burial depth range of 20–650 and 800–2400?m, respectively, are usually interbedded with coal and compact sandstone reservoirs due to their special sedimentary environment. Geochemical analysis of the samples of Longtan shales from seven wells in the Yangtze area indicates the presence of high organic matters (OMs), with a total organic carbon content in the range of 0.85%–35.7% (average of 7.33%) but low hydrocarbon genetic potential (S2) with a value below 3?mg HC/g rock. The analysis of carbon isotopes and organic macerals demonstrates that the investigated samples mainly contain type III kerogen. Data from gas chromatography and gas chromatography-mass spectrometry analyses illustrate a weakly oxidizing to a weakly reducing environment, with most organic materials originating from algal-bacterial organisms and terrestrial plants. The terrestrial plants contribute significantly to the OM. The Longtan shales are thermally over-matured, and they have entered the dry-gas generation window according to Ro, production index data, and biomarker maturity ratios. X-ray diffraction analyses show that the content of brittle minerals of the Longtan shales is generally lower than that of marine shales in North America. The Longtan shales show a high clay content averaging 60.32?wt% and low calcite mineral content averaging 3.73?wt%. Field emission scanning electron microscopy shows that various types of nanometer-to micrometer-scale pores, including interparticle and intraparticle pores, OM pores, and microfractures, are well developed in the shales. Generally, high OM abundance, thermal evolution degree, clay mineral content, and pore space (porosity of 0.56%–10.6%) positively influence shale gas content (1.0%–3.8%). However, high clay content and variable reservoir thickness hinder the successful production of shale gas.Zhang, J., Zhang, C., Zhu, Y., Li, J., Li, X., 2018. Biodegradation of seven phthalate esters by Bacillus mojavensis B1811. International Biodeterioration & Biodegradation 132, 200-207. esters (PAEs) are one of the most widely used groups of plasticizers and have been considered threats to the environment and human health. This study investigated the efficient biodegradation of seven phthalate esters (PAEs) by Bacillus mojavensis B1811. The results showed that di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), benzyl butyl phthalate (BBP) and dipentyl phthalate (DPP) could be almost completely degraded by strain B1811 within four days in mineral salt medium (MSM) under shaking conditions, while only 5.9% of the dimethyl phthalate (DMP) and 42.9% of the diethyl phthalate (DEP) present, which both have short alkyl chains, were degraded by strain B1811 under the same conditions. An esterase activity assay also indicated that the specific activities of esterases induced by PAEs with longer alkyl chains were much higher than those of esterases induced by PAEs with short alkyl chains. High-performance liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS) was applied to identify the major metabolites of the seven PAEs. The PAEs were first degraded to the corresponding phthalate monoesters and then degraded to phthalic acid; phthalic acid was rapidly degraded to produce benzoic acid which was subsequently converted to protocatechuate and ultimately transformed to CO2 and H2O. The optimal conditions for biodegradation were also obtained and an exponential model was the best model to represent the PAEs depletion. It is therefore concluded that B. mojavensis B1811 offers great application potential in the bioremediation of environments polluted with PAEs.Zhang, L.-J., Buatois, L.A., Mángano, M.G., Gong, Y.-M., Feng, Q.-L., Qi, Y.-A., Luo, M., Zhang, X., 2018. Uppermost Permian trace fossils along a shelf to slope transect in South China and their implications for oceanic redox evolution and extinction pattern. Global and Planetary Change 167, 74-86. fossils are important evidence of benthic activity and proxies of bottom and interstitial water oxygen content, making them a promising tool to understand the oceanic redox evolution and extinction patterns during the end-Permian mass extinction (EPME). Detailed bed-by-bed ichnologic studies were performed at a high-resolution scale from two uppermost Permian sections (Shangsi and Dongpan) in South China, documenting the presence of Chondrites targionii, Chondrites isp., Nereites isp., Planolites isp. A, Planolites isp. B, Palaeophycus isp., Phycosiphon incertum, Thalassinoides isp., and Zoophycos isp. The uppermost Permian strata at the Shangsi section mainly comprise siliceous limestone interbedded with illite-montmorillonite claystone and shale, recording a deep shelf setting. The uppermost Permian strata at the Dongpan section consist of mixed chert, mudstone and claystone, formed in a slope environment. Bioturbation index in uppermost Permian strata is mostly 1–2, but with thin intervals reaching 3–4. Fluctuating bioturbation intensities, ichnofaunal composition (Thalassinoides, Planolites, Zoophycos) and ethologies, as well as the ratio of highly reactive iron to total iron (FeHr/FeT) and the proportion of the highly reactive iron pool in the form of pyrite (Fepy/FeHR) suggest that bottom and interstitial oxygen levels were not permanently anoxic/euxinic, but were interrupted by brief periods of aerobic conditions during the latest Permian. Three bioturbation phases in the EPME are identified. Phase I is characterized by the absence of typical pascichnia ichnotaxa (e.g. Nereites isp.) and relatively large fodinichnia burrow (e.g., Planolites isp. B; Zoophycos isp.). Phase II mainly consists of smaller Planolites isp. A, Thalassinoides isp. and Chondrites isp., recording a transition from softground to firmground. Only occasional smaller Planolites isp. A occur in Phase III without any associated vertical burrows. Ichnodiversity and bioturbation index from Phase I to Phase III show a step by step decline, corresponding to the two-stage extinction patterns. Long-term environmental stress (e.g., oceanic anoxia, volcanic winter, global warming, ocean acidification, hypercapnia) may have played major role in the collapse of the infaunal ecospace and only facies-crossing, highly tolerant, opportunistic organisms may have persisted in otherwise vacant ecological niches in the aftermath of the extinction.Zhang, L., Li, B., Jiang, S., Xiao, D., Lu, S., Zhang, Y., Gong, C., Chen, L., 2018. Heterogeneity characterization of the lower Silurian Longmaxi marine shale in the Pengshui area, South China. International Journal of Coal Geology 195, 250-266. heterogeneity of shale is significant for the evaluation and “sweet spot” prediction of a shale gas reservoir. Core observations, thin sections, field emission scanning electron microscopy (FE-SEM), nitrogen gas adsorption (N2GA) and geochemical analyses were performed on shale samples from the Lower Longmaxi Formation in the Pengshui area of South China. In this study, the macroscopic and microscopic heterogeneities of the Longmaxi shale are revealed, and their origins and inner link are also discussed. The results show that three systems tracts were developed in the Lower Longmaxi Formation: a transgressive systems tract (TST), early highstand systems tract (EHST) and late highstand systems tract (LHST). From TST to LHST, TOC (total organic carbon), siliceous minerals (quartz+feldspar), and pyrite show an upward decreasing trend in weight content, while the clay minerals and carbonate contents increase upward. Hence, the TST, EHST and LHST shales are generally characterized by organic-rich shale lithofacies, organic-moderate shale lithofacies, and organic-lean shale lithofacies, respectively. The in situ gas content decreases from TST to LHST and primarily depends on TOC content. The sedimentary environment of the TST shale is an anoxic environment with high paleoproductivity, which then evolves to a dysoxic-oxic environment in the EHST shale and an oxic environment in the LHST shale with relatively low paleoproductivity. Organic matter pores are the primary contributors to the total pore volume in the TST shale, and then, the pore content and role in porosity decrease upward from EHST to LHST. However, the proportions of clay-related pores and brittle mineral-related pores gradually elevate from the TST shale to the LHST shale. The sedimentary environment, including water depth, redox conditions, paleoproductivity, terrigenous input and hydrodynamics, etc., control the development of organic matter, mineral composition, lithofacies association, color, bedding and palaeobios in the Lower Longmaxi shales, which constitute the macroscopic heterogeneity. Nevertheless, the microscopic heterogeneity of shale originates from diagenesis/catagenesis. Specifically, shales are primarily composed of interparticle pores and clay-related pores during deposition, and the porosity is reduced primarily under mechanical compaction and chemical cementation. As the burial depth and diagenetic degree increase, a large number of organic matter pores and dissolution pores begin to appear, which are associated with the hydrocarbon generation process. Moreover, macroscopic shale composition plays a crucial role in development levels of microscopic shale pores.Zhang, L., Lu, S., Jiang, S., Xiao, D., Chen, L., Liu, Y., Zhang, Y., Li, B., Gong, C., 2018. Effect of shale lithofacies on pore structure of the Wufeng–Longmaxi Shale in southeast Chongqing, China. Energy & Fuels 32, 6603-6618. organic carbon (TOC), optical microscopy, field emission scanning electron microscopy, X-ray diffraction, and nitrogen gas adsorption analyses were performed on shale samples from the Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation (Wufeng–Longmaxi Formation) in order to explore the effect of shale lithofacies on pore structure. The results show that the Wufeng–Longmaxi shale consists of four types of pores: organic matter pores, interparticle pores, intraparticle pores, and microfracture pores. A total of eight kinds of shale lithofacies were identified on the basis of TOC and the ternary diagram of siliceous minerals (quartz and feldspar), clay, and carbonate. The geological properties have substantial heterogeneity in these shale lithofacies. The volumes of organic matter (OM) and clay-related and brittle mineral-related pores are 0.00119–0.01262, 0.00080–0.00260, and 0.00122–0.00215 cm3/g, with an average proportion of 51.85%, 26.44%, and 21.71%, respectively. The specific surface area (SSA) values derived from OM, clay, and brittle minerals range from 2.35 to 24.70 m2/g, from 1.89 to 6.12 m2/g, and from 0.21 to 0.37 m2/g, with a mean percentage of 60.18%, 37.50%, and 2.32%, respectively. The pore volume and SSA of organic-rich siliceous shale (ORSS) and organic-rich mixed shale (ORMS) are primarily contributed by OM, while those of organic-lean siliceous, organic-lean mixed, and organic-lean argillaceous shales (OLSS, OLMS, and OLAS, respectively) are mainly contributed by clay. OM is the dominant positive controller of pore volume and SSA, and its control level declines with decreasing OM content. However, clay is weakly negatively correlated with both pore volume and SSA. The micropores (<2 nm) and mesopores (2–50 nm) principally originate from OM, whereas the development of macropores (>50 nm) is related to inorganic minerals. ORSS is the most favorable facies for shale gas storage due to the substantial SSA and pore volume resulting from the high OM content and consists mainly of micropores and mesopores, while OLSS, OLMS, and OLAS have a much lower shale gas storage capacity corresponding to relatively more macropores due to the very small SSA and small pore volume resulting from the low OM content.Zhang, M., Li, Z., Yin, J., 2018. Sedimentary and geochemical characteristics of oil shale in the Permian Lucaogou Formation in the southeastern Junggar Basin, northwest China: Implications for sedimentary environments Oil Shale 35, 97–112. this study, the sedimentary and geochemical characteristics of oil shale in the Lower and the Upper Member of the Permian Lucaogou Formation in the southeastern Junggar Basin, Northwest China, were investigated. Mineral and bulk chemical compositions, sedimentary facies and distribution of oil shale show that in the Lower Member it is rich in organic matter, but in the Upper Member, organic-poor. The distribution area of deep lake subfacies and oil shale in the Lower Member is larger than that in the Upper Member. The sedimentary modes of these two members were estimated using geochemical parameters, such as Sr/Cu, the chemical index of alteration (CIA), Ni/Co, V/Sc and (C27 + C28)/C29 regular steranes. The organic-rich oil shale in the Lower Member of the Lucaogou Formation formed in the more humid climate and under oxidative conditions, its organic matter derived mainly from algae. On the other hand, the organic-poor oil shale in the formation’s Upper Member formed in the humid climate and under more oxidative conditions, while the input of land plants to its organic matter was high and that of algae low.Zhang, N., Zhao, F., Guo, P., Li, J., Gong, W., Guo, Z., Sun, X., 2018. Nanoscale pore structure characterization and permeability of mudrocks and fine-grained sandstones in coal reservoirs by scanning electron microscopy, mercury intrusion porosimetry, and low-field nuclear magnetic resonance. Geofluids 2018, 20. and permeability of two typical sedimentary rocks in coal bearing strata of underground coal mines in China, i.e., mudrocks and fine-grained sandstones, were comprehensively investigated by multiple experimental methods. Measured porosity averages of the helium gas porosity (φg), MIP porosity (φMIP), water porosity (φw), and NMR porosity (φNMR) of the twelve investigated rock samples range from 1.78 to 16.50% and the measured gas permeabilities (Kg) range from 0.0003 to 2.4133?mD. Meanwhile, pore types, pore morphologies, and pore size distributions (PSD) were determined by focused ion beam scanning electron microscopy (FIB-SEM), mercury intrusion porosimetry (MIP), and low-field nuclear magnetic resonance (NMR). FIB-SEM image analyses showed that the mineral matrix pores including interparticle (interP) and intraparticle (intraP) pores with varied morphologies are the dominant pore types of the investigated rock samples while very few organic matter (OM) pores were observed. Results of the MIP and the full water-saturated NMR measurements showed that the PSD curves of the mudrock samples mostly present a unimodal pattern and nanopores with pore diameter less than 0.1?μm are their predominant pore type, while the PSD curves of the fine-grained sandstone samples are featured by a bimodal distribution. Furthermore, comparison of the full water-saturated and irreducible-water-saturated NMR measurements indicated that pores in the mudrocks are solely adsorption pores (normally pore size < 0.1?μm) whereas apart from a fraction of adsorption pores, a large part of the pores in the sandstone sample with relatively high porosity are seepage pores (normally pore size > 0.1?μm). Moreover, the PSD curves of NMR quantitatively converted from the NMR T2 spectra by T2PC and weighted arithmetic mean (WAM) methods are in good agreement with the PSD curves of MIP. Finally, the applicability of three classic permeability estimation models based on MIP and NMR data to the investigated rock samples was evaluated.Zhang, Y.-L., Gong, C., Pei, X.-L., Han, Y.-L., Huang, Y.-Y., Xu, X., 2018. Rapid quantitative determination of triglycerides in edible oils by matrix-assisted laser desorption/ionisation Fourier transform ion cyclotron resonance mass spectrometry using pencil graphite combined with 2,5-dihydroxybenzoic acid as matrix. International Journal of Mass Spectrometry 431, 56-62. rapid quantitative method based on matrix-assisted laser desorption/ionisation Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FT-ICR–MS) was established for the repeatable determination of triglycerides in edible oil. In this method, pencil graphite combined with 2,5-dihydroxybenzoic acid (DHB) was used as a matrix. The method was applied to determine the presence of animal fat adulterants in vegetable oil by quantitative analysis of the differences between the MS peaks of vegetable oil and animal fat. A solution of the edible oil sample and DHB matrix was spotted on a MALDI target plate coated with 2B pencil graphite. The characteristic profiles of triglycerides in edible oil were then quantitatively determined by MALDI-FT-ICR–MS, which provided the MS spectra of edible oils and reproducible MS peak intensity. Moreover, MS/MS can be used to qualitatively determine the molecular structure of triglycerides in edible oil. The presence of 10% lard or mutton fat in corn oil was directly recognised. Results suggested that MALDI FT-ICR–MS is a suitable method for the quantitative analysis of triglycerides and the identification of adulterants in edible oils.Zhang, Y., Gao, W., Lin, F., Han, B., He, C., Li, Q., Gao, X., Cui, Z., Sun, C., Zheng, L., 2018. Study on immobilization of marine oil-degrading bacteria by carrier of algae materials. World Journal of Microbiology and Biotechnology 34, 70. study investigated the immobilizations with of bacteria two kinds of algal materials, Enteromorpha residue and kelp residue. The lipophilicity of them were compared by diesel absorption rates. The immobilization efficiency of Bacillus sp. E3 was measured to evaluate whether these carriers would satisfy the requirement for biodegradation of oil spills. The bacteria were immobilized through adsorption with the sterilized and non-sterilized carriers to compare the differences between the two treatments. Oil degradation rates were determined using gravimetric and GC–MS methods. Results showed the absorption rates of Enteromorpha residue and kelp residue for diesel were 411 and 273% respectively and remained approximately 105 and 120% after 2?h of erosion in simulated seawater system. After immobilized of Bacillus sp. E3, the oil degradation rates of them were higher than 65% after 21 days biodegradations. GC–MS analysis showed that two immobilizations degraded higher than 70% of the total alkane and the total PAHs, whereas the free bacteria degraded 63% of the total alkane and 66% the total PAHs. And the bacteria immobilized with the carriers degraded more HMW–alkanes and HMW-PAHs than the free bacteria. The bacteria immobilized by non-sterilized kelp residue showed a considerably higher degradation rate than that using sterilized kelp residue. A considerably higher cells absorption rate of immobilization was obtained when using kelp residue, and the preparation of immobilization was low cost and highly efficient. The experiments show the two algae materials, especially the kelp residue, present potential application in bioremediation of marine oil spills.Zhao, R., Zhang, C., Yang, F., Heng, M., Shao, P., Wang, Y., 2018. Influence of temperature field on rock and heavy components variation during in-situ combustion process. Fuel 230, 244-257. temperature field generated during an in-situ combustion (ISC) process sees dramatic variation from 50?°C to over 700?°C. The division of the reservoir into different temperature regions during an ISC process induces different phase state transition and chemical reactions, resulting in serious heterogeneity in oil compositions and reaction products. Combustion tube experiments were conducted to investigate the propagation behavior of combustion front, combined with outlook color observation of down-hole rock samples, permeability measurements (N2) and organic residual analysis. Fourier transform infrared spectroscopy (FTIR) and gas chromatography–mass spectrometry (GC–MS) were used to characterize the organic materials extracted from the combustion zones. X-ray diffraction (XRD) was employed to investigate the variation of mineral components before and after the ISC process. The results indicated that most of calcite component in the down-hole rock sample was decomposed in combustion front regions within the highest temperature range of 550–650?°C. The color transfer from light grey to brick-red in the outlook color observation demonstrated that an even higher temperature can be achieved. Permeability measurement had shown that secondary diagenetic reaction involving clay triggered a significant permeability reduction during the ISC process. This study demonstrated that variation of oil compositions from different locations of formation can serve as a direct indicator to the occurrence of fire chamber enlargement.Zhao, X., Wang, X., Shi, X., Tang, D., Shi, Q., 2018. Stepwise oxygenation of early Cambrian ocean controls early metazoan diversification. Palaeogeography, Palaeoclimatology, Palaeoecology 504, 86-103. Ediacaran–Cambrian transition is a critical period in Earth history, during which both marine environment and life experienced drastic changes. It was suggested that pervasive oxygenation and associated chemical changes in the ocean have potentially triggered the rapid diversification of early Cambrian metazoans. The timing and process of ocean oxygenation, however, have not been well constrained. In this paper, an integrated study was conducted on the lower Cambrian Niutitang (NTT) Formation in Siduping area, western Hunan, which was paleogeographically located at shelf margin–upper slope setting of the Yangtze Platform. Using ICP-MS, Element Analyzer, FESEM, EDS and XRD techniques, the abundance of RSEs (redox sensitive elements), patterns of RSEs distribution, pyrite morphology, TOC (total organic carbon), TS (total sulfur), SPY (pyrite sulfur) as well as N and P contents were investigated systematically. The results show that during the NTT deposition, bottom seawater in the study area experienced a complicated evolution, with a dynamic alternation of three ferruginous and three euxinic intervals, and suboxic–oxic conditions occurring only in the latest Cambrian Stage 3. Comparison with relevant sections reported previously from other facies belts within the Yangtze Platform shows that the seawater oxygenation was a progressive process expanding from shallow to deep-water areas in time. Shallow-water platform area became oxygenated in the late Cambrian Stage 2, shelf margin area in the late Cambrian Stage 3, and the deep-water basin remained ferruginous until the latest Cambrian Stage 3, when it became euxinic. Sediment Mo/TOC, U/TOC ratios increased from bottom to top in the section, coupled with elevated Mn, N and P secular trends, likely indicating an overall enhancement of seawater oxygenation. The spatial-temporal distribution and increased paleoecologic complexity of major fossil groups on the Yangtze Platform over time coincide with the seawater oxygenation process, likely implying that increased ocean oxygenation and declining euxinic seawaters have driven the rapid diversification of early Cambrian metazoans.Zhao, X., Zeng, Z., Chen, A., Lu, X., Zhao, C., Hu, C., Zhou, L., Liu, X., Wang, X., Hou, X., Ye, Y., Xu, G., 2018. Comprehensive strategy to construct in-house database for accurate and batch identification of small molecular metabolites. Analytical Chemistry 90, 7635-7643. of the metabolites is an essential step in metabolomics study to interpret the regulatory mechanism of pathological and physiological processes. However, it is still difficult in LC–MSn-based studies because of the complexity of mass spectrometry, chemical diversity of metabolites, and deficiency of standards database. In this work, a comprehensive strategy is developed for accurate and batch metabolite identification in nontargeted metabolomics studies. First, a well-defined procedure was applied to generate reliable and standard LC–MS2 data, including tR, MS1, and MS2 information at a standard operational procedure. An in-house database including about 2000 metabolites was constructed and used to identify the metabolites in nontargeted metabolic profiling by retention time calibration using internal standards, precursor ion alignment and ion fusion, auto-MS2 information extraction and selection, and database batch searching and scoring. As an application example, a pooled serum sample was analyzed to deliver the strategy, and 202 metabolites were identified in the positive ion mode. It shows our strategy is useful for LC–MSn-based nontargeted metabolomics study.Zhao, X., Zhou, L., Pu, X., Jin, F., Han, W., Xiao, D., Chen, S., Shi, Z., Zhang, W., Yang, F., 2018. Geological characteristics of shale rock system and shale oil exploration breakthrough in a lacustrine basin: A case study from the Paleogene 1st sub-member of Kong 2 Member in Cangdong sag, Bohai Bay Basin, China. Petroleum Exploration and Development 45, 377-388. deep understanding of the basic geologic characteristics of the fine-grained shale layers in the Paleogene 1st sub-member of Kong 2 Member (Ek21) in Cangdong sag, Bohai Bay Basin, is achieved through observation of 140 m continuous cores and systematic analysis of over 1 000 core samples from two wells. Basic geological conditions for shale oil accumulation are proposed based on the unconventional geological theory of oil and gas. The shale rock system mainly developed interbedded formation of felsic shale, calcareous and dolomitic shale and carbonates; high quality hydrocarbon source rock formed in the stable and closed environment is the material base for shale oil enrichment; intergranular pores in analcite, intercrystalline pores in dolomite and interlayer micro-fractures make tight carbonate, calcareous and dolomitic shale and felsic shale effective reservoirs, with brittle mineral content of more than 70%; high abundance laminated shale rock in the lower section of Ek21 is rich in shale oil, with a total thickness of 70 m, burial depth between 2 800 to 4 200 m, an average oil saturation of 50%, a sweet spot area of 260 km2 and predicted resources of over 5×108 t. Therefore, this area is a key replacement domain for oil exploration in the Kongdian Formation of the Cangdong sag. At present, the KN9 vertical well has a daily oil production of 29.6 t after fracturing with a 2 mm choke. A breakthrough of continental shale oil exploration in a lacustrine basin is expected to be achieved by volume fracturing in horizontal wells.Zhong, Z.-P., Solonenko, N.E., Gazitúa, M.C., Kenny, D.V., Mosley-Thompson, E., Rich, V.I., Van Etten, J.L., Thompson, L.G., Sullivan, M.B., 2018. Clean low-biomass procedures and their application to ancient ice core microorganisms. Frontiers in Microbiology 9, 1094. doi: 1010.3389/fmicb.2018.01094. in glacier ice provide tens to hundreds of thousands of years archive for a changing climate and microbial responses to it. Analyzing ancient ice is impeded by technical issues, including limited ice, low biomass, and contamination. While many approaches have been evaluated and advanced to remove contaminants on ice core surfaces, few studies leverage modern sequencing to establish in silico decontamination protocols for glacier ice. Here we sought to apply such “clean” sampling techniques with in silico decontamination approaches used elsewhere to investigate microorganisms archived in ice at ～41 (D41, ～20,000 years) and ～49 m (D49, ～30,000 years) depth in an ice core (GS3) from the summit of the Guliya ice cap in the northwestern Tibetan Plateau. Four “background” controls were established – a co-processed sterile water artificial ice core, two air samples collected from the ice processing laboratories, and a blank, sterile water sample – and used to assess contaminant microbial diversity and abundances. Amplicon sequencing revealed 29 microbial genera in these controls, but quantitative PCR showed that the controls contained about 50–100-times less 16S DNA than the glacial ice samples. As in prior work, we interpreted these low-abundance taxa in controls as “contaminants” and proportionally removed them in silico from the GS3 ice amplicon data. Because of the low biomass in the controls, we also compared prokaryotic 16S DNA amplicons from pre-amplified (by re-conditioning PCR) and standard amplicon sequencing, and found the resulting microbial profiles to be repeatable and nearly identical. Ecologically, the contaminant-controlled ice microbial profiles revealed significantly different microorganisms across the two depths in the GS3 ice core, which is consistent with changing climate, as reported for other glacier ice samples. Many GS3 ice core genera, including Methylobacterium, Sphingomonas, Flavobacterium, Janthinobacterium, Polaromonas, and Rhodobacter, were also abundant in previously studied ice cores, which suggests wide distribution across glacier environments. Together these findings help further establish “clean” procedures for studying low-biomass ice microbial communities and contribute to a baseline understanding of microorganisms archived in glacier ice.Zhou, X., Hou, Z., Wang, J., Fang, W., Ma, A., Guo, J., Klein, M.T., 2018. Molecular-level kinetic model for C12 continuous catalytic reforming. Energy & Fuels 32, 7078-7085. detailed kinetic model for a continuous catalytic reforming (CCR) process was developed. The model included 447 naphtha molecules (C1–C12) that underwent 1469 reactions. Paraffin and naphthenic isomers up to C9 components were fully depicted, whereas aromatic isomers were fully described up to C10. Coking kinetics and the corresponding deactivation of the catalyst were integrated into the model. The steady state kinetic parameters were tuned using pilot plant data for a widely used industrial catalyst. To enable the use of commercial plant data, the energy balance and catalyst moving mechanism of typical CCR reactors were also formulated. The model was then used to simulate an industrial unit loaded with the same catalyst after deactivation calibration by adjusting a few deactivation parameters. The results showed that calculated PONA fractions, individual aromatic species, and the temperature drops of each reactor were in good accord with industrial data.Zhu, G., Wang, M., Zhang, Y., Zhang, Z., 2018. Low-molecular-weight organic polysulfanes in petroleum. Energy & Fuels 32, 6770-6773. series of acyclic and cyclic organic polysulfanes with three to six sulfur atoms are identified for the first time in petroleum (Ma3 well condensate) from the Tarim Basin, China. These organic polysulfanes are speculated to form through the nucleophilic addition reaction of hydrosulfide anion or polysulfides anions with low-molecular-weight aldehydes like formaldehyde in geochemical environment. The detection of these organic polysulfanes implies the incorporation of inorganic sulfur into organic matter during diagenesis, which helps to reconstruct the paleoenvironment and identify the oil source.Zhu, P., Luo, A., Zhang, F., Lei, Z., Zhang, J., Zhang, J., 2018. Effects of extractable compounds on the structure and pyrolysis behaviours of two Xinjiang coal. Journal of Analytical and Applied Pyrolysis 133, 128-135. extractable compounds are a very important part of coal and play an important role in the pyrolysis of coal. To further understand the effect of the extracts on the structure and pyrolysis behaviours of coal, Naomaohu (NMH) lignite and Hutubi (HTB) bituminous coal were extracted with pyridine and swollen with its solvent vapor. The pyrolysis process was performed in a fixed-bed reactor. Thermogravimetric analysis (TGA) of the coal samples was carried out on a thermogravimetric (TG) analyser. The pore structure characteristics of the coal samples and their chars obtained from pyrolysis at different temperatures were measured by the mercury intrusion porosimetry (MIP) method. The components of the pyrolysis gas were detected by gas chromatography (GC). It was found that the extraction and swelling processes enlarged the pore size and improved the porosity of the coals to some extent. Compared with the pyrolysis of the raw coal, that of the swollen coal resulted in a higher tar yield owing to the destruction of the cross-linked structure and the variations in the coal structure; the tar yield for the pyrolysis of all the residues decreased significantly, but the gas yield increased, where the volume of the CO gas mainly increased. The NMH residue char obtained from pyrolysis of the residue at different temperatures had a lower proportion of micropores than the HTB residue char. The extractable compounds will be converted to gas-phase (e.g. volatiles) and liquid-phase (e.g. colloids) products during the pyrolysis process, which could stabilise the free radical fragments, form coke in the pore structure of the char and increase the number of new micropores formed.Zhu, Y., Sun, L., Hao, F., Tuo, L., 2018. Geochemical composition and origin of Tertiary oils in the Yinggehai and Qiongdongnan Basins, offshore South China Sea. Marine and Petroleum Geology 96, 139-153. study comprehensively characterizes the geochemical compositions of Tertiary crude oils in the Yinggehai and Qiongdongnan Basins, offshore South China Sea, and differentiates their source properties using chemical and isotopic data. The oils in the two basins have distinct source characteristics. The majority of the oils from the Yacheng (YC) field in the Qiongdongnan Basin are commonly marked by high Pr/Ph ratios (mostly from 4.5 to 7.0), unusually abundant angiosperm-derived compounds and a domination of C29 in diasteranes, suggesting a predominantly terrigenous organic source. In contrast, the oils from the Dongfang (DF) and Ledong (LD) fields in the Yinggehai Basin have relatively lower Pr/Ph values (2.5–5.5) and a low amount of bicadinanes. Moreover, some oils in this basin contain abundant 4-methylsteranes and detectable C30 desmethyl steranes. The difference in the molecular composition is also apparent with regard to the aromatic hydrocarbons. The former oils contain more abundant biphenyls, fluorenes and 2-phenylnaphthalene than the latter ones. The oils from the Qiongdongnan Basin are relatively depleted in 13C and have δ13C values of the whole oil in the range of ?24.9 to ?26.9‰, consistent with the great terrigenous input. In contrast, the Yinggehai oils are isotopically heavier with δ13C values from ?21.6 to ?23.6‰, typical of a marine isotope signature. Correspondingly, their n-alkane isotopes have different δ13C ranges and exhibit distinct distribution profiles. Based on the oil-source rock correlation, the oils in the YC field were generated from the coastal plain-swamp and shallow marine strata of the Oligocene in the Qiongdongnan Basin, while the Yinggehai oils were sourced from the Miocene shallow marine mudstones in the basin.Zhu, Y., Yan, C., Liu, Q., Masliyah, J., Xu, Z., 2018. Biodiesel-assisted ambient aqueous bitumen extraction (BA3BE) from Athabasca oil sands. Energy & Fuels 32, 6565-6576. water-based extraction process has been almost exclusively used in the current industry for Athabasca oil sands extraction to produce bitumen and heavy oil. However, the current method is facing various challenges, primarily including high energy intensity, poor processability with poor-quality ores, large consumption of fresh water, and concerns on considerable volume of tailings. Although the technology of using nonaqueous solvent as extraction medium has numerous advantages, problems such as solvent loss to tailings and high capital/operating costs are difficult to address. A biodiesel-assisted ambient aqueous bitumen extraction (BA3BE) process has been herein proposed as an alternative to water-based and solvent-based extraction processes. The results showed a significant improvement in both froth quality and bitumen recovery (increased from ～10% to ～80% with biodiesel addition) for processing poor-quality ores at ambient temperature (25 °C), which is much lower than the temperatures used in the current industrial practice (40–55 °C). The aqueous tailings generated in the BA3BE process were found to feature faster settling and enhanced densification, which is favorable for recovering processing water and improving land reclamation. Furthermore, the innovative BA3BE extraction process requires similar facilities and procedures as the current industrial processes, which can be considered as an advantage for commercialization.Zinke, L.A., Reese, B.K., McManus, J., Wheat, C.G., Orcutt, B.N., Amend, J.P., 2018. Sediment microbial communities influenced by cool hydrothermal fluid migration. Frontiers in Microbiology 9, 1249. doi: 1210.3389/fmicb.2018.01249. hydrothermal systems (CHS) are prevalent across the seafloor and discharge fluid volumes that rival oceanic input from rivers, yet the microbial ecology of these systems are poorly constrained. The Dorado Outcrop on the ridge flank of the Cocos Plate in the northeastern tropical Pacific Ocean is the first confirmed CHS, discharging minimally altered < 15?C fluid from the shallow lithosphere through diffuse venting and seepage. In this paper we characterize the resident sediment microbial communities influenced by cool hydrothermal advection, which is evident from nitrate and oxygen concentrations. 16S rRNA gene sequencing revealed that Thaumarchaea, Proteobacteria, and Planctomycetes were the most abundant phyla in all sediments across the system regardless of influence from seepage. Members of the Thaumarchaeota (Marine Group I), Alphaproteobacteria (Rhodospirallales), Nitrospirae, Nitrospina, Acidobacteria, and Gemmatimonadetes were enriched in the sediments influenced by CHS advection. Of the various geochemical parameters investigated, nitrate concentrations correlated best with microbial community structure, indicating structuring based on seepage of nitrate-rich fluids. A comparison of microbial communities from hydrothermal sediments, seafloor basalts, and local seawater at Dorado Outcrop showed differences that highlight the distinct niche space in CHS. Sediment microbial communities from Dorado Outcrop differ from those at previously characterized, warmer CHS sediment, but are similar to deep-sea sediment habitats with surficial ferromanganese nodules, such as the Clarion Clipperton Zone. We conclude that cool hydrothermal venting at seafloor outcrops can alter the local sedimentary oxidation-reduction pathways, which in turn influences the microbial communities within the fluid discharge affected sediment.Zou, C., Qiu, Z., Poulton, S.W., Dong, D., Wang, H., Chen, D., Lu, B., Shi, Z., Tao, H., 2018. Ocean euxinia and climate change “double whammy” drove the Late Ordovician mass extinction. Geology 46, 535-538. Late Ordovician mass extinction (LOME, ca. 445 Ma) was the first of the “Big Five” Phanerozoic extinction events and comprised two extinction pulses. Proposed kill mechanisms include glacially induced global cooling and the expansion of water-column anoxia and/or euxinia (sulfidic conditions), but no general consensus has been reached with regard to the precise role of these mechanisms. A more definitive understanding is hampered by poorly constrained temporal links between the extinction pulses and climate change, and by uncertainty over the spatial distribution and intensity of euxinia. Here, we utilize Fe speciation and Mo concentrations, in addition to the chemical index of alteration weathering proxy, to reconstruct ocean redox conditions and climate change across a Late Ordovician to Early Silurian shelf-to-slope transect on the Yangtze Shelf Sea (a siliciclastic-dominated shelf basin in South China). These data show two cycles of expanded euxinia corresponding to the two pulses of the LOME, suggesting a strong causal relationship. Significantly, we show that intermittent or weak euxinia developed during the first extinction pulse, which likely accounts for the loss of benthic fauna and some planktonic organisms and nektonic groups. By contrast, the development of more intense euxinia throughout the water column during the second pulse likely drove survival fauna to extinction. Superimposed upon this, significant global cooling occurred across the first extinction phase, reflecting a secondary role in driving the extinction of certain low-latitude taxa.Zou, J., Rezaee, R., Xie, Q., You, L., Liu, K., Saeedi, A., 2018. Investigation of moisture effect on methane adsorption capacity of shale samples. Fuel 232, 323-332. existing moisture in shale samples makes the evaluation for shale gas reservoirs more difficult due to its impact on the methane adsorption capacity and pore structure measurements. This paper compares the pore structure characteristics and methane adsorption capacity between dry and wet shale samples from Perth Basin, Western Australia. Pores with size between 0.4?nm and 100?nm were quantified by low-pressure N2 and CO2 adsorption. The comparative results demonstrate that moisture could alter the pore size distribution for big pores (>16?nm) and small pores (0.4–16?nm) in different ways.For each sample, the moisture effect on methane adsorption in shales changes with pressure: moisture effect on methane adsorption is more pronounced at lower pressure than higher pressure. For all samples, the effect of moisture on methane adsorption is related to the total organic carbon (TOC) content. Moisture could reduce methane adsorption by blocking clay- hosted small pores directly and organic matter-hosted small pores indirectly in high TOC samples. This phenomenon can effectively lead to a reduced Langmuir volume (VL) and increased Langmuir pressure (PL) when moisture exists.Zuo, J., Peng, S., Qi, Y., Zhu, X., Bagnoli, G., Fang, H., 2018. Carbon-isotope excursions recorded in the Cambrian system, South China: Implications for mass extinctions and sea-level fluctuations. Journal of Earth Science 29, 479-491. carbonates with abundant fossils of agnostoid trilobites deposited on the southern slope (Jiangnan slope belt) of the Yangtze Platform and in the Jiangnan deepwater basin are well exposed in the Wangcun Section of western Hunan, South China, and in the Duibian A Section of western Zhejiang, southeastern China, respectively. To better understand the response of carbon-isotope excursions to depositional environment changes, mass extinctions and eustatic events, we collected 530 carbonate samples in fresh roadcut exposures of the two measured sections for analysis of carbon and oxygen isotopic compositions. Data of δ13C from the Wangcun Section, western Hunan, South China, demonstrate that the Cambrian carbon-isotope profile includes three remarkable positive excursions CPEwc -1, 2, 3 in the Upper Series 2, in the Lower and in the Middle Furongian Series. Three distinctive negative excursions CNEwc -1, 2, 3 were separately tested in the Lower Terreneuvian Series, Lower Series 3 and in the Upper Furongian Series. Similarly, in the corresponding horizons in the Duibian A Section, Zhejiang Province, southeastern China, three positive excursions CPEdb -1, 2, 3 and three negative excursions CNEdb -1, 2, 3 also have been discovered. We interpret these significant carbon-isotope excursions as being associated with enhanced biogenic productivity, mass extinctions and eustatic events. ................
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