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GEOCHEMISTRY ARTICLES – April 2018?Analytical ChemistryBaludikay, B.K., Fran?ois, C., Sforna, M.C., Beghin, J., Cornet, Y., Storme, J.-Y., Fagel, N., Fontaine, F., Littke, R., Baudet, D., Delvaux, D., Javaux, E.J., 2018. Raman microspectroscopy, bitumen reflectance and illite crystallinity scale: comparison of different geothermometry methods on fossiliferous Proterozoic sedimentary basins (DR Congo, Mauritania and Australia). International Journal of Coal Geology 191, 80-94.Henry, D.G., Jarvis, I., Gillmore, G., Stephenson, M., Emmings, J.F., 2018. Assessing low-maturity organic matter in shales using Raman spectroscopy: Effects of sample preparation and operating procedure. International Journal of Coal Geology 191, 135-151.Kong, F., Zhao, P., Ye, X., Wang, Z., Qin, Z., Yu, P., Su, J., Shi, F., Du, J., 2018. Nanoscale zero-field electron spin resonance spectroscopy. Nature Communications 9, article 1563.Shkolyar, S., Eshelman, E.J., Farmer, J.D., Hamilton, D., Daly, M.G., Youngbull, C., 2018. Detecting kerogen as a biosignature using colocated UV time-gated Raman and fluorescence spectroscopy. Astrobiology 18, 431-453.Stach, R., Pejcic, B., Heath, C., Myers, M., Mizaikoff, B., 2018. Mid-infrared sensor for hydrocarbon monitoring: the influence of salinity, matrix and aging on hydrocarbon-polymer partitioning. Analytical Methods 10, 1516-1522.Gas Chromatography/GC×GC/GC-MSAnthony, I.G.M., Brantley, M.R., Gaw, C.A., Floyd, A.R., Solouki, T., 2018. Vacuum ultraviolet spectroscopy and mass spectrometry: A tandem detection approach for improved identification of gas chromatography-eluting compounds. Analytical Chemistry 90, 4878-4885.Bressanello, D., Liberto, E., Collino, M., Chiazza, F., Mastrocola, R., Reichenbach, S.E., Bicchi, C., Cordero, C., 2018. Combined untargeted and targeted fingerprinting by comprehensive two-dimensional gas chromatography: revealing fructose-induced changes in mice urinary metabolic signatures. Analytical and Bioanalytical Chemistry 410, 2723-2737.Gai, Q., Liu, C., Zhao, S., Dong, H., Zhao, X., 2018. Separation and identification of Fischer-Tropsch wax by high temperature gas chromatography-mass spectrometry. Chinese Journal of Chromatography 36, 303-308.Garaniya, V., McWilliam, D., Goldsworthy, L., Ghiji, M., 2018. Extensive chemical characterization of a heavy fuel oil. Fuel 227, 67-78.Jiang, M., Kulsing, C., Marriott, P.J., 2018. Comprehensive 2D gas chromatography–time-of-flight mass spectrometry with 2D retention indices for analysis of volatile compounds in frankincense (Boswellia papyrifera). Analytical and Bioanalytical Chemistry 410, 3185-3196.Lengger, S.K., Sutton, P.A., Rowland, S.J., Hurley, S.J., Pearson, A., Naafs, B.D.A., Dang, X., Inglis, G.N., Pancost, R.D., 2018. Archaeal and bacterial glycerol dialkyl glycerol tetraether (GDGT) lipids in environmental samples by high temperature-gas chromatography with flame ionisation and time-of-flight mass spectrometry detection. Organic Geochemistry 121, 10-21.Liu, Y., Wang, X., Li, Y., Chen, X., 2018. Metabolomic analysis of short-term sulfamethazine exposure on marine medaka (Oryzias melastigma) by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry. Aquatic Toxicology 198, 269-275.Waktola, H.D., Kulsing, C., Nolvachai, Y., Marriott, P.J., 2018. High temperature multidimensional gas chromatographic approach for improved separation of triacylglycerols in olive oil. Journal of Chromatography A 1549, 77-84.Waktola, H.D., Mj?s, S.A., 2018. Chromatographic efficiency of polar capillary columns applied for the analysis of fatty acid methyl esters by gas chromatography. Journal of Separation Science 41, 1582-1592.Wang, Q., Cui, D., Pan, S., Wang, Z., Liu, Q., Liu, B., 2018. Compositional characterization of neutral fractions in <300?°C distillates of six shale oils using extrography followed by GC-TOF/MS analysis. Fuel 224, 610-618.Wotherspoon, A.T.L., Reeves, K.L., Crawford, J., 2018. A comparison of structural-functional equation models to identify fatty acids on three common gas chromatography columns. Analytical Methods 10, 1747-1759.Yan, D., Wong, Y.F., Whittock, S.P., Koutoulis, A., Shellie, R.A., Marriott, P.J., 2018. Sequential hybrid three-dimensional gas chromatography with accurate mass spectrometry: A novel tool for high-resolution characterization of multicomponent samples. Analytical Chemistry 90, 5264-5271.Yang, X., Imasaka, T., Imasaka, T., 2018. Determination of pesticides by gas chromatography combined with mass spectrometry using femtosecond lasers emitting at 267, 400, and 800 nm as the ionization source. Analytical Chemistry 90, 4886-4893.Imaging: SEM, TEM, HIM, AFMByrne, J.M., Schmidt, M., Gauger, T., Bryce, C., Kappler, A., 2018. Imaging organic-mineral aggregates formed by Fe(II)-oxidizing bacteria using helium ion microscopy. Environmental Science & Technology Letters 5, 209–213.Cardott, B.J., Curtis, M.E., 2018. Identification and nanoporosity of macerals in coal by scanning electron microscopy. International Journal of Coal Geology 190, 205-217.Earl, L.A., Falconieri, V., Subramaniam, S., 2018. Microbiology catches the cryo-EM bug. Current Opinion in Microbiology 43, 199-207.Gong, Y., Liu, K., Liu, S., 2018. Determining the occurrence of oil in micro/nanopores of tight sand: A new approach using environmental scanning electron microscopy combined with energy-dispersive spectrometry. Energy & Fuels 32, 4885-4893.He, J., Wang, J., Yu, Q., Liu, W., Ge, X., Yang, P., Wang, Z., Lu, J., 2018. Pore structure of shale and its effects on gas storage and transmission capacity in well HD-1 eastern Sichuan Basin, China. Fuel 226, 709-720.Kang, J., Sun, Y., Men, Y., Tian, J., Yu, Q., Yan, J., Lin, J., Liu, J., 2018. Shale gas enrichment conditions in the frontal margin of Dabashan orogenic belt, south China. Journal of Natural Gas Science and Engineering 54, 11-24.Ko, L.T., Ruppel, S.C., Loucks, R.G., Hackley, P.C., Zhang, T., Shao, D., 2018. Pore-types and pore-network evolution in Upper Devonian-Lower Mississippian Woodford and Mississippian Barnett mudstones: Insights from laboratory thermal maturation and organic petrology. International Journal of Coal Geology 190, 3-28.Liang, C., Cao, Y., Liu, K., Jiang, Z., Wu, J., Hao, F., 2018. Diagenetic variation at the lamina scale in lacustrine organic-rich shales: Implications for hydrocarbon migration and accumulation. Geochimica et Cosmochimica Acta 229, 112-128.Nabiei, F., Badro, J., Dennenwaldt, T., Oveisi, E., Cantoni, M., Hébert, C., El Goresy, A., Barrat, J.-A., Gillet, P., 2018. A large planetary body inferred from diamond inclusions in a ureilite meteorite. Nature Communications 9, Article 1327.Pi, X., Tian, L., Dai, H.-E., Qin, X., Cheng, L., Kuang, T., Sui, S.-F., Shen, J.-R., 2018. Unique organization of photosystem I–light-harvesting supercomplex revealed by cryo-EM from a red alga. Proceedings of the National Academy of Sciences 115, 4423-4428.Presentato, A., Cappelletti, M., Sansone, A., Ferreri, C., Piacenza, E., Demeter, M.A., Crognale, S., Petruccioli, M., Milazzo, G., Fedi, S., Steinbüchel, A., Turner, R.J., Zannoni, D., 2018. Aerobic growth of Rhodococcus aetherivorans BCP1 using selected naphthenic acids as the sole carbon and energy sources. Frontiers in Microbiology 9, 672. doi: 610.3389/fmicb.2018.00672.Sarkar, P., Kumar, A., Singh, K.H., Ghosh, R., Singh, T.N., 2018. Pore system, microstructure and porosity characterization of Gondwana shale of Eastern India using laboratory experiment and watershed image segmentation algorithm. Marine and Petroleum Geology 94, 246-260.Subramanian, P., Pirbadian, S., El-Naggar, M.Y., Jensen, G.J., 2018. Ultrastructure of Shewanella oneidensis MR-1 nanowires revealed by electron cryotomography. Proceedings of the National Academy of Sciences 115, E3246-E3255.Wu, H., Zhang, C., Ji, Y., Liu, R., Wu, H., Zhang, Y., Geng, Z., Zhang, Y., Yang, J., 2018. An improved method of characterizing the pore structure in tight oil reservoirs: Integrated NMR and constant-rate-controlled porosimetry data. Journal of Petroleum Science and Engineering 166, 778-796.Xin, Y., Shi, Y., Niu, T., Wang, Q., Niu, W., Huang, X., Ding, W., Yang, L., Blankenship, R.E., Xu, X., Sun, F., 2018. Cryo-EM structure of the RC-LH core complex from an early branching photosynthetic prokaryote. Nature Communications 9, Article 1568.Zhang, S., Tang, S., Zhang, J., Pan, Z., 2018. Pore structure characteristics of China sapropelic coal and their development influence factors. Journal of Natural Gas Science and Engineering 53, 370-384.Imaging: Xray CTGonzalez, J.L., de Faria, E.L., Albuquerque, M.P., Albuquerque, M.P., Bom, C.R., Freitas, J.C.C., Cremasco, C.W., Correia, M.D., 2018. Representative elementary volume for simulations based on X-ray microtomography of sedimentary rock. Journal of Petroleum Science and Engineering 166, 906-912.He, J., Wang, J., Yu, Q., Liu, W., Ge, X., Yang, P., Wang, Z., Lu, J., 2018. Pore structure of shale and its effects on gas storage and transmission capacity in well HD-1 eastern Sichuan Basin, China. Fuel 226, 709-720.Li, J., Gao, Y., Jiang, H., Liu, Y., Dong, H., 2018. Pore-scale imaging of the oil cluster dynamic during drainage and imbibition using in situ X-ray microtomography. Geofluids 2018, Article 7679607.Lu, X., Armstrong, R.T., Mostaghimi, P., 2018. High-pressure X-ray imaging to interpret coal permeability. Fuel 226, 573-582.Pennetta de Oliveira, L., Gumfekar, S.P., Lopes Motta, F., Soares, J.B.P., 2018. Dewatering of oil sands tailings with novel chitosan-based flocculants. Energy & Fuels 32, 5271-5278.Sun, Y., Zhao, Y., Yuan, L., 2018. CO2-ECBM in coal nanostructure: Modelling and simulation. Journal of Natural Gas Science and Engineering 54, 202-215.Wang, D., Wang, C., Li, C., Liu, C., Lu, H., Wu, N., Hu, G., Liu, L., Meng, Q., 2018. Effect of gas hydrate formation and decomposition on flow properties of fine-grained quartz sand sediments using X-ray CT based pore network model simulation. Fuel 226, 516-526.Watanabe, H., 2018. X-ray CT visualization of woody char intra-particle pore structure and its role on anisotropic evolution during char gasification. Energy & Fuels 32, 4248-4254.Zhou, Y., Wu, S., Li, Z., Zhu, R., Xie, S., Jing, C., Lei, L., 2018. Multifractal study of three-dimensional pore structure of sand-conglomerate reservoir based on CT images. Energy & Fuels 32, 4797-4807.Liquid Chromatography/LC-MS/SFCAl Hamimi, S., Sandahl, M., Armeni, M., Turner, C., Spégel, P., 2018. Screening of stationary phase selectivities for global lipid profiling by ultrahigh performance supercritical fluid chromatography. Journal of Chromatography A 1548, 76-82.Apel, N., Uliyanchenko, E., Moyses, S., Rommens, S., Wold, C., Macko, T., Brüll, R., 2018. Separation of branched poly(bisphenol a carbonate) structures by solvent gradient at near-critical conditions and two-dimensional liquid chromatography. Analytical Chemistry 90, 5422-5429.Baert, M., Martens, S., Desmet, G., de Villiers, A., Du Prez, F., Lynen, F., 2018. Enhancing the possibilities of comprehensive two-dimensional liquid chromatography through hyphenation of purely aqueous temperature-responsive and reversed-phase liquid chromatography. Analytical Chemistry 90, 4961-4967.Crepier, J., Le Masle, A., Charon, N., Albrieux, F., Duchene, P., Heinisch, S., 2018. Ultra-high performance supercritical fluid chromatography hyphenated to atmospheric pressure chemical ionization high resolution mass spectrometry for the characterization of fast pyrolysis bio-oils. Journal of Chromatography B 1086, 38-46.Guan, Z., Wang, M., Cai, Y., Yang, H., Zhao, M., Zhao, C., 2018. Rapid characterization of the chemical constituents of Sijunzi decoction by UHPLC coupled with Fourier transform ion cyclotron resonance mass spectrometry. Journal of Chromatography B 1086, 11-22.Nagai, K., Shibata, T., Shinkura, S., Ohnishi, A., 2018. Poly(butylene terephthalate) based novel achiral stationary phase investigated under supercritical fluid chromatography conditions. Journal of Chromatography A 1549, 85-92.Pauk, V., Lemr, K., 2018. Forensic applications of supercritical fluid chromatography – mass spectrometry. Journal of Chromatography B 1086, 184-196.Samanipour, S., Reid, M.J., B?k, K., Thomas, K.V., 2018. Combining a deconvolution and a universal library search algorithm for the nontarget analysis of data-independent acquisition mode liquid chromatography?high-resolution mass spectrometry results. Environmental Science & Technology 52, 4694-4701.Shi, X., Yang, W., Qiu, S., Hou, J., Wu, W., Guo, D., 2018. Systematic profiling and comparison of the lipidomes from Panax ginseng, P. quinquefolius, and P. notoginseng by ultrahigh performance supercritical fluid chromatography/high-resolution mass spectrometry and ion mobility-derived collision cross section measurement. Journal of Chromatography A 1548, 64-75.Storbeck, K.-H., Gilligan, L., Jenkinson, C., Baranowski, E.S., Quanson, J.L., Arlt, W., Taylor, A.E., 2018. The utility of ultra-high performance supercritical fluid chromatography–tandem mass spectrometry (UHPSFC-MS/MS) for clinically relevant steroid analysis. Journal of Chromatography B 1085, 36-41.Wicker, A.P., Carlton, D.D., Tanaka, K., Nishimura, M., Chen, V., Ogura, T., Hedgepeth, W., Schug, K.A., 2018. On-line supercritical fluid extraction—supercritical fluid chromatography-mass spectrometry of polycyclic aromatic hydrocarbons in soil. Journal of Chromatography B 1086, 82-88.Mass Spectroscopy/ICR-FTMS/OrbitrapAsghar, M.A., Zhu, Q., Sun, S., Peng, Y.e., Shuai, Q., 2018. Suspect screening and target quantification of human pharmaceutical residues in the surface water of Wuhan, China, using UHPLC-Q-Orbitrap HRMS. Science of The Total Environment 635, 828-837.Chen, X., Xu, C., Zhang, W., Ma, C., Liu, X., Zhao, S., Shi, Q., 2018. Separation and molecular characterization of ketones in a low-temperature coal tar. Energy & Fuels 32, 4662-4670.Ga?parovi?, B., Penezi?, A., Frka, S., Kazazi?, S., Lampitt, R.S., Holguin, F.O., Sudasinghe, N., Schaub, T., 2018. Particulate sulfur-containing lipids: Production and cycling from the epipelagic to the abyssopelagic zone. Deep Sea Research Part I: Oceanographic Research Papers 134, 12-22.Guan, Z., Wang, M., Cai, Y., Yang, H., Zhao, M., Zhao, C., 2018. Rapid characterization of the chemical constituents of Sijunzi decoction by UHPLC coupled with Fourier transform ion cyclotron resonance mass spectrometry. Journal of Chromatography B 1086, 11-22.Gutiérrez Sama, S., Farenc, M., Barrère-Mangote, C., Lobinski, R., Afonso, C., Bouyssière, B., Giusti, P., 2018. Molecular fingerprints and speciation of crude oils and heavy fractions revealed by molecular and elemental mass spectrometry: Keystone between petroleomics, metallopetroleomics, and petrointeractomics. Energy & Fuels 32, 4593-4605.Han, Y., Poetz, S., Mahlstedt, N., Karger, C., Horsfield, B., 2018. Fractionation of pyrrolic nitrogen compounds compounds during primary migration of petroleum within the Barnett Shale sequence of Marathon 1 Mesquite Well, Texas. Energy & Fuels 32, 4638-4650.Li, L., He, Z.L., Tfaily, M.M., Inglett, P., Stoffella, P.J., 2018. Spatial-temporal variations of dissolved organic nitrogen molecular composition in agricultural runoff water. Water Research 137, 375-383.Liu, W., Liao, Y., Shi, Q., Hsu, S.C., Jiang, B., Peng, P.a., 2018. Origin of polar organic sulfur compounds in immature crude oils revealed by ESI FT–ICR MS. Organic Geochemistry 121, 36-47.Lv, J., Han, R., Huang, Z., Luo, L., Cao, D., Zhang, S., 2018. Relationship between molecular components and reducing capacities of humic substances. ACS Earth and Space Chemistry 2, 330-339.MacLennan, M.S., Peru, K.M., Swyngedouw, C., Fleming, I., Chen, D.D.Y., Headley, J.V., 2018. Characterization of Athabasca lean oil sands and mixed surficial materials: Comparison of capillary electrophoresis/low‐resolution mass spectrometry and high‐resolution mass spectrometry. Rapid Communications in Mass Spectrometry 32, 695-702.Melendez-Perez, J.J., Martínez-Mejía, M.J., Barcellos, R.L., Fetter-Filho, A.F.H., Eberlin, M.N., 2018. A potential formation route for CHOS compounds in dissolved organic matter. Marine Chemistry 202, 67-72.Mo, Y., Li, J., Jiang, B., Su, T., Geng, X., Liu, J., Jiang, H., Shen, C., Ding, P., Zhong, G., Cheng, Z., Liao, Y., Tian, C., Chen, Y., Zhang, G., 2018. Sources, compositions, and optical properties of humic-like substances in Beijing during the 2014 APEC summit: Results from dual carbon isotope and Fourier-transform ion cyclotron resonance mass spectrometry analyses. Environmental Pollution 239, 322-331.Prentice, B.M., Ryan, D.J., Van de Plas, R., Caprioli, R.M., Spraggins, J.M., 2018. Enhanced ion transmission efficiency up to m/z 24?000 for MALDI protein imaging mass spectrometry. Analytical Chemistry 90, 5090-5099.Romero, C.M., Engel, R.E., D'Andrilli, J., Chen, C., Zabinski, C., Miller, P.R., Wallander, R., 2018. Patterns of change in permanganate oxidizable soil organic matter from semiarid drylands reflected by absorbance spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry. Organic Geochemistry 120, 19-30.Souza, L.M., Tose, L.V., Cardoso, F.M.R., Fleming, F.P., Pinto, F.E., Kuster, R.M., Filgueiras, P.R., Vaz, B.G., Rom?o, W., 2018. Evaluating the effect of ion source gas (N2, He, and synthetic air) on the ionization of hydrocarbon, condensed aromatic standards, and paraffin fractions by APCI(+)FT-ICR MS. Fuel 225, 632-645.Wang, W., Dong, M., Song, C., Cai, X., Liu, Y., Liu, Z., Tian, S., 2018. Structural information of asphaltenes derived from petroleum vacuum residue and its hydrotreated product obtained by FT-ICR mass spectrometry with narrow ion isolation windows. Fuel 227, 111-117.Wang, Y., Xu, Y., Spencer, R.G.M., Zito, P., Kellerman, A., Podgorski, D., Xiao, W., Wei, D., Rashid, H., Yang, Y., 2018. Selective leaching of dissolved organic matter from alpine permafrost soils on the Qinghai‐Tibetan Plateau. Journal of Geophysical Research: Biogeosciences 123, 1005-1016.Ziegs, V., Noah, M., Poetz, S., Horsfield, B., Hartwig, A., Rinna, J., Skeie, J.E., 2018. Unravelling maturity- and migration-related carbazole and phenol distributions in Central Graben crude oils. Marine and Petroleum Geology 94, 114-130.Mass Spectroscopy/OtherBasuri, P., Sarkar, D., Paramasivam, G., Pradeep, T., 2018. Detection of hydrocarbons by laser assisted paper spray ionization mass spectrometry (LAPSI MS). Analytical Chemistry 90, 4663-4668.Galey, M.M., Sanchez, L.M., 2018. Spatial analyses of specialized metabolites: The key to studying function in hosts. mSystems 3, DOI: 10.1128/mSystems.00148-00117.Giraldo-Dávila, D., Chacón-Pati?o, M.L., Ramirez-Pradilla, J.S., Blanco-Tirado, C., Combariza, M.Y., 2018. Selective ionization by electron-transfer MALDI-MS of vanadyl porphyrins from crude oils. Fuel 226, 103-111.Hernández-Mesa, M., Le Bizec, B., Monteau, F., García-Campa?a, A.M., Dervilly-Pinel, G., 2018. Collision cross section (CCS) database: An additional measure to characterize steroids. Analytical Chemistry 90, 4616-4625.Hu, W., Day, D.A., Campuzano-Jost, P., Nault, B.A., Park, T., Lee, T., Croteau, P., Canagaratna, M.R., Jayne, J.T., Worsnop, D.R., Jimenez, J.L., 2018. Evaluation of the new capture vaporizer for aerosol mass spectrometers (AMS): Elemental composition and source apportionment of organic aerosols (OA). ACS Earth and Space Chemistry 2, 410-421.Lai, Z., Fiehn, O., 2018. Mass spectral fragmentation of trimethylsilylated small molecules. Mass Spectrometry Reviews 37, 245-257.Mirabelli, M.F., Zenobi, R., 2018. Solid-phase microextraction coupled to capillary atmospheric pressure photoionization-mass spectrometry for direct analysis of polar and nonpolar compounds. Analytical Chemistry 90, 5015-5022.Murugaiyan, J., Lewin, A., Kamal, E., Baku?a, Z., van Ingen, J., Ulmann, V., Unzaga Bara?ano, M.J., Humi?cka, J., Safianowska, A., Roesler, U.H., Jagielski, T., 2018. MALDI spectra database for rapid discrimination and subtyping of Mycobacterium kansasii. Frontiers in Microbiology 9, 587. doi: 510.3389/fmicb.2018.00587.Poad, B.L.J., Maccarone, A.T., Yu, H., Mitchell, T.W., Saied, E.M., Arenz, C., Hornemann, T., Bull, J.N., Bieske, E.J., Blanksby, S.J., 2018. Differential-mobility spectrometry of 1-deoxysphingosine isomers: New insights into the gas phase structures of ionized lipids. Analytical Chemistry 90, 5343-5351.Prentice, B.M., Ryan, D.J., Van de Plas, R., Caprioli, R.M., Spraggins, J.M., 2018. Enhanced ion transmission efficiency up to m/z 24?000 for MALDI protein imaging mass spectrometry. Analytical Chemistry 90, 5090-5099.Rahman, M.M., Chen, L.C., 2018. Analytical characteristics of nano-electrospray operated under super-atmospheric pressure. Analytica Chimica Acta 1021, 78-84.Ràfols, P., Vilalta, D., Brezmes, J., Ca?ellas, N., del Castillo, E., Yanes, O., Ramírez, N., Correig, X., 2018. Signal preprocessing, multivariate analysis and software tools for MA(LDI)‐TOF mass spectrometry imaging for biological applications. Mass Spectrometry Reviews 37, 281-306. Rontani, J.F., Aubert, C., Belt, S.T., 2018. Electron ionization mass spectrometry fragmentation and multiple reaction monitoring quantification of bacterial metabolites of the sea ice biomarker proxy IP25 in Arctic sediments. Rapid Communications in Mass Spectrometry 32, 775-783.Sandrin, T.R., Demirev, P.A., 2018. Characterization of microbial mixtures by mass spectrometry. Mass Spectrometry Reviews 37, 321-349.Souza, L.M., Tose, L.V., Cardoso, F.M.R., Fleming, F.P., Pinto, F.E., Kuster, R.M., Filgueiras, P.R., Vaz, B.G., Rom?o, W., 2018. Evaluating the effect of ion source gas (N2, He, and synthetic air) on the ionization of hydrocarbon, condensed aromatic standards, and paraffin fractions by APCI(+)FT-ICR MS. Fuel 225, 632-645.Trivella, D.B.B., de Felicio, R., 2018. The tripod for bacterial natural product discovery: Genome mining, silent pathway induction, and mass spectrometry-based molecular networking. mSystems 3, DOI: 10.1128/mSystems.00160-00117.Wang, Y., Hua, L., Li, Q., Jiang, J., Hou, K., Wu, C., Li, H., 2018. Direct detection of small n-alkanes at sub-ppbv level by photoelectron-induced O2+ cation chemical ionization mass spectrometry at kPa pressure. Analytical Chemistry 90, 5398-5404.Metabolomics/LipidomicsAl Hamimi, S., Sandahl, M., Armeni, M., Turner, C., Spégel, P., 2018. Screening of stationary phase selectivities for global lipid profiling by ultrahigh performance supercritical fluid chromatography. Journal of Chromatography A 1548, 76-82.Beale, D.J., Crosswell, J., Karpe, A.V., Metcalfe, S.S., Morrison, P.D., Staley, C., Ahmed, W., Sadowsky, M.J., Palombo, E.A., Steven, A.D.L., 2018. Seasonal metabolic analysis of marine sediments collected from Moreton Bay in South East Queensland, Australia, using a multi-omics-based approach. Science of The Total Environment 631–632, 1328-1341.Caesar, L.K., Kvalheim, O.M., Cech, N.B., 2018. Hierarchical cluster analysis of technical replicates to identify interferents in untargeted mass spectrometry metabolomics. Analytica Chimica Acta 1021, 69-77.Dubbelman, A.-C., Cuyckens, F., Dillen, L., Gross, G., Vreeken, R.J., Hankemeier, T., 2018. Mass spectrometric recommendations for Quan/Qual analysis using liquid-chromatography coupled to quadrupole time-of-flight mass spectrometry. Analytica Chimica Acta 1020, 62-75.Galey, M.M., Sanchez, L.M., 2018. Spatial analyses of specialized metabolites: The key to studying function in hosts. mSystems 3, DOI: 10.1128/mSystems.00148-00117.Ga?parovi?, B., Penezi?, A., Frka, S., Kazazi?, S., Lampitt, R.S., Holguin, F.O., Sudasinghe, N., Schaub, T., 2018. Particulate sulfur-containing lipids: Production and cycling from the epipelagic to the abyssopelagic zone. Deep Sea Research Part I: Oceanographic Research Papers 134, 12-22.Hol?apek, M., Liebisch, G., Ekroos, K., 2018. Lipidomic analysis. Analytical Chemistry 90, 4249-4257.Lai, Z., Fiehn, O., 2018. Mass spectral fragmentation of trimethylsilylated small molecules. Mass Spectrometry Reviews 37, 245-257.Liu, Y., Wang, X., Li, Y., Chen, X., 2018. Metabolomic analysis of short-term sulfamethazine exposure on marine medaka (Oryzias melastigma) by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry. Aquatic Toxicology 198, 269-275.Martin, M., Legat, B., Leenders, J., Vanwinsberghe, J., Rousseau, R., Boulanger, B., Eilers, P.H.C., De Tullio, P., Govaerts, B., 2018. PepsNMR for 1H NMR metabolomic data pre-processing. Analytica Chimica Acta 1019, 1-13.Ortiz-Villanueva, E., Jaumot, J., Martínez, R., Navarro-Martín, L., Pi?a, B., Tauler, R., 2018. Assessment of endocrine disruptors effects on zebrafish (Danio rerio) embryos by untargeted LC-HRMS metabolomic analysis. Science of The Total Environment 635, 156-166.Palazzotto, E., Weber, T., 2018. Omics and multi-omics approaches to study the biosynthesis of secondary metabolites in microorganisms. Current Opinion in Microbiology 45, 109-116.Poad, B.L.J., Maccarone, A.T., Yu, H., Mitchell, T.W., Saied, E.M., Arenz, C., Hornemann, T., Bull, J.N., Bieske, E.J., Blanksby, S.J., 2018. Differential-mobility spectrometry of 1-deoxysphingosine isomers: New insights into the gas phase structures of ionized lipids. 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Integrated analysis of geoelectric and surface geochemical data for exploration of subsurface hydrocarbon accumulations (Carpathian Foredeep, SE Poland). Journal of Petroleum Science and Engineering 167, 524-537.Zwicker, J., Birgel, D., Bach, W., Richoz, S., Smrzka, D., Grasemann, B., Gier, S., Schleper, C., Rittmann, S.K.M.R., Ko?un, E., Peckmann, J., 2018. Evidence for archaeal methanogenesis within veins at the onshore serpentinite-hosted Chimaera seeps, Turkey. Chemical Geology 483, 567-580.Source Rocks/Depositional EnvironmentsBaludikay, B.K., Fran?ois, C., Sforna, M.C., Beghin, J., Cornet, Y., Storme, J.-Y., Fagel, N., Fontaine, F., Littke, R., Baudet, D., Delvaux, D., Javaux, E.J., 2018. Raman microspectroscopy, bitumen reflectance and illite crystallinity scale: comparison of different geothermometry methods on fossiliferous Proterozoic sedimentary basins (DR Congo, Mauritania and Australia). International Journal of Coal Geology 191, 80-94.Beik, I., Gómez, V.G., Podlaha, O.G., Mutterlose, J., 2018. The δ13C record of Maastrichtian-Paleocene oil shales from Jordan – Stratigraphic and environmental implications for an epicontinental setting. Journal of African Earth Sciences 143, 134-144.Borrego, A.G., López García, A., Merino-Tomé, O., 2018. Petrographic and geochemical characterization of organic-rich Mississippian black shales in the north of Spain: Vegamián Formation, Cantabrian Zone. International Journal of Coal Geology 190, 126-145.Carvajal-Ortiz, H., Gentzis, T., 2018. Geochemical screening of source rocks and reservoirs: The importance of using the proper analytical program. International Journal of Coal Geology 190, 56-69.Cirilli, S., Panfili, G., Buratti, N., Frixa, A., 2018. Paleoenvironmental reconstruction by means of palynofacies and lithofacies analyses: An example from the Upper Triassic subsurface succession of the Hyblean Plateau Petroleum System (SE Sicily, Italy). Review of Palaeobotany and Palynology 253, 70-87.Craddock, P.R., Bake, K.D., Pomerantz, A.E., 2018. Chemical, molecular, and microstructural evolution of kerogen during thermal maturation: Case study from the Woodford Shale of Oklahoma. Energy & Fuels 32, 4859-4872.Deaf, A.S., Tahoun, S.S., 2018. Integrated palynological, organic geochemical, and sequence stratigraphic analyses of the middle to upper Cenomanian hydrocarbon reservoir/source Abu Roash “G” Member: A depositional model in northwestern Egypt. Marine and Petroleum Geology 92, 372-402.Fernández‐Remolar, D.C., Harir, M., Carrizo, D., Schmitt‐Kopplin, P., Amils, R., 2018. Productivity contribution of Paleozoic woodlands to the formation of shale‐hosted massive sulfide deposits in the Iberian Pyrite Belt (Tharsis, Spain). Journal of Geophysical Research: Biogeosciences 123, 1017-1040.Fonseca, C., Mendon?a Filho, J.G., Lézin, C., Duarte, L.V., Fauré, P., 2018. Organic facies variability during the Toarcian Oceanic Anoxic Event record of the Grands Causses and Quercy basins (southern France). International Journal of Coal Geology 190, 218-235.Gentzis, T., Carvajal-Ortiz, H., Deaf, A., Tahoun, S.S., 2018. Multi-proxy approach to screen the hydrocarbon potential of the Jurassic succession in the Matruh Basin, North Western Desert, Egypt. International Journal of Coal Geology 190, 29-41.G?tz, A.E., Ruckwied, K., Wheeler, A., 2018. Marine flooding surfaces recorded in Permian black shales and coal deposits of the Main Karoo Basin (South Africa): Implications for basin dynamics and cross-basin correlation. International Journal of Coal Geology 190, 178-190.Henry, D.G., Jarvis, I., Gillmore, G., Stephenson, M., Emmings, J.F., 2018. Assessing low-maturity organic matter in shales using Raman spectroscopy: Effects of sample preparation and operating procedure. International Journal of Coal Geology 191, 135-151.Hu, T., Pang, X., Jiang, S., Wang, Q., Xu, T., Lu, K., Huang, C., Chen, Y., Zheng, X., 2018. Impact of paleosalinity, dilution, redox, and paleoproductivity on organic matter enrichment in a saline lacustrine rift basin: A case study of paleogene organic-rich shale in Dongpu Depression, Bohai Bay Basin, eastern China. Energy & Fuels 32, 5045-5061.Jiang, K., Lin, C., Zhang, X., Cai, C., Xiao, F., He, W., Peng, L., 2018. Variations in abundance and distribution of methyltrimethyltridecylchromans (MTTCs) in sediments from saline lacustrine settings in Cenozoic lacustrine basins, China. Organic Geochemistry 121, 58-67.Lai, H., Li, M., Liu, J., Mao, F., Yang, L., Yang, C., Xiao, H., 2018. Source rock types and logging evaluation in forced regressive systems tract: Taking the Termit Basin (Niger) as an example. Acta Sedimentologica Sinica 36, 390-400.Li, M., Chen, Z., Ma, X., Cao, T., Li, Z., Jiang, Q., 2018. A numerical method for calculating total oil yield using a single routine Rock-Eval program: A case study of the Eocene Shahejie Formation in Dongying Depression, Bohai Bay Basin, China. International Journal of Coal Geology 191, 49-65.Liang, C., Cao, Y., Liu, K., Jiang, Z., Wu, J., Hao, F., 2018. Diagenetic variation at the lamina scale in lacustrine organic-rich shales: Implications for hydrocarbon migration and accumulation. Geochimica et Cosmochimica Acta 229, 112-128.Lorente, F.L., Pessenda, L.C.R., Oboh-Ikuenobe, F., Buso Junior, A.A., Rossetti, D.d.F., Giannini, P.C.F., Cohen, M.C.L., de Oliveira, P.E., Mayle, F.E., Francisquini, M.I., Fran?a, M.C., Bendassolli, J.A., Macario, K., 2018. An 11,000-year record of depositional environmental change based upon particulate organic matter and stable isotopes (C and N) in a lake sediment in southeastern Brazil. Journal of South American Earth Sciences 84, 373-384.Luo, Q., Zhong, N., Liu, Y., Qu, Y., Ma, L., 2018. Organic geochemical characteristics and accumulation of the organic matter in the Jurassic to Cretaceous sediments of the Saihantala Sag, Erlian Basin, China. Marine and Petroleum Geology 92, 855-867.Naimark, E.B., Boeva, N.M., Kalinina, M.A., Zaytseva, L.V., 2018. Complementary transformations of buried organic residues and the ambient sediment: Results of long-term taphonomic experiments. Paleontological Journal 52, 109-122.Ocubalidet, S.G., Rimmer, S.M., Conder, J.A., 2018. Redox conditions associated with organic carbon accumulation in the Late Devonian New Albany Shale, west-central Kentucky, Illinois Basin. International Journal of Coal Geology 190, 42-55.Petersen, H.I., Hertle, M., 2018. A review of the coaly source rocks and generated petroleums in the Danish North Sea: An underexplored middle Jurassic petroleum system? Journal of Petroleum Geology 41, 135-154.Phelps, A.S., Hofmann, M.H., Hart, B.S., 2018. Facies and stratigraphic architecture of the Upper Devonian–Lower Mississippian Sappington Formation, southwestern Montana: A potential outcrop analog for the Bakken Formation. American Association of Petroleum Geologists Bulletin 102, 793-815.Rakociński, M., Zatoń, M., Marynowski, L., Gedl, P., Lehmann, J., 2018. Redox conditions, productivity, and volcanic input during deposition of uppermost Jurassic and Lower Cretaceous organic-rich siltstones in Spitsbergen, Norway. Cretaceous Research 89, 126-147.Reinhardt, M., Duda, J.P., Blumenberg, M., Ostertag‐Henning, C., Reitner, J., Heim, C., Thiel, V., 2018. The taphonomic fate of isorenieratene in Lower Jurassic shales—controlled by iron? Geobiology 16, 237-251.Shi, C., Cao, J., Tan, X., Luo, B., Zeng, W., Hong, H., Huang, X., Wang, Y., 2018. Hydrocarbon generation capability of Sinian–Lower Cambrian shale, mudstone, and carbonate rocks in the Sichuan Basin, southwestern China: Implications for contributions to the giant Sinian Dengying natural gas accumulation. American Association of Petroleum Geologists Bulletin 102, 817-853.Tahoun, S.S., Deaf, A.S., Gentzis, T., Carvajal-Ortiz, H., 2018. Modified RGB-based kerogen maturation index (KMI): Correlation and calibration with classical thermal maturity indices. International Journal of Coal Geology 190, 70-83.Tang, X., Zhang, J., Liu, Y., Yang, C., Chen, Q., Dang, W., Zhao, P., 2018. Geochemistry of organic matter and elements of black shale during weathering in Northern Guizhou, Southwestern China: Their mobilization and inter-connection. Chemie der Erde 78, 140-151.Thiel, V., Hoppert, M., 2018. Fatty acids and other biomarkers in two Early Jurassic concretions and their immediate host rocks (Lias δ, Buttenheim clay pit, Bavaria, Germany). Organic Geochemistry 120, 42-55.Wan, Y., Zhang, S., Tang, S., Pan, Z., Wu, W., 2018. A comparative study of characterization of lower Palaeozoic Niutitang shale in northwestern Hunan, China. Journal of Natural Gas Science and Engineering 53, 284-300.Wei, G., Wang, Z., Li, J., Yang, W., Xie, Z., 2017. Characteristics of source rocks, resource potential and exploration direction of Sinian-Cambrian in Sichuan Basin, China. Journal of Natural Gas Geoscience 2, 289-302.Wei, W., Zhu, X., He, M., Wang, M., Liu, X., 2018. Original sediment composition of the Lower Cretaceous lacustrine tight-oil mudstone and influences on diagenesis and organic matter content, the Erennaoer Sag in Erlian Basin, NE China. Marine and Petroleum Geology 94, 131-143.Xiong, X., Wang, J., Xiong, G., Wang, Z., Zhou, X., Deng, Q., Zhou, Y., Yang, X., 2018. Sedimentation and geochemistry of Upper Ordovician-Lower Silurian from northern Chongqing, and its environmental evolution: A study of Linxiang Formation to Longmaxi Formation of Yanmai profile from Chengkou Region. Acta Sedimentologica Sinica 36, 257-266.Yan, C., Jin, Z., Zhao, J., Du, W., Liu, Q., 2018. Influence of sedimentary environment on organic matter enrichment in shale: A case study of the Wufeng and Longmaxi Formations of the Sichuan Basin, China. Marine and Petroleum Geology 92, 880-894.Zhu, B., Jiang, S., Pi, D., Ge, L., Yang, J., 2018. Trace elements characteristics of black shales from the Ediacaran Doushantuo Formation, Hubei Province, South China: Implications for redox and open vs. restricted basin conditions. Journal of Earth Science 29, 342-352.Yurchenko, I.A., Moldowan, J.M., Peters, K.E., Magoon, L.B., Graham, S.A., 2018. Source rock heterogeneity and migrated hydrocarbons in the Triassic Shublik Formation and their implication for unconventional resource evaluation in Arctic Alaska. Marine and Petroleum Geology 92, 932-952.Zhu, D., Liu, Q., Meng, Q., Jin, Z., 2018. Enhanced effects of large-scale CO2 transportation on oil accumulation in oil-gas-bearing basins — Implications from supercritical CO2 extraction of source rocks and a typical case study. Marine and Petroleum Geology 92, 493-504.Unconventional ResourcesAlfarge, D., Wei, M., Bai, B., 2018. CO2-EOR mechanisms in huff-n-puff operations in shale oil reservoirs based on history matching results. Fuel 226, 112-120.Ardakani, O.H., Sanei, H., Ghanizadeh, A., Lavoie, D., Chen, Z., Clarkson, C.R., 2018. Do all fractions of organic matter contribute equally in shale porosity? A case study from Upper Ordovician Utica Shale, southern Quebec, Canada. Marine and Petroleum Geology 92, 794-808.Chen, G., Lu, S., Liu, K., Han, T., Xu, C., Xue, Q., Shen, B., Guo, Z., 2018. GCMC simulations on the adsorption mechanisms of CH4 and CO2 in K-illite and their implications for shale gas exploration and development. Fuel 224, 521-528.Chen, G., Lu, S., Zhang, J., Pervukhina, M., Liu, K., Wang, M., Han, T., Tian, S., Li, J., Zhang, Y., Xu, C., 2018. A method for determining oil-bearing pore size distribution in shales: A case study from the Damintun Sag, China. Journal of Petroleum Science and Engineering 166, 673-678.Chen, Q., Deng, Y., Wei, J., Ma, G., Long, L., Xiao, W., Li, W., Zhang, L., 2018. Types, distribution and play targets of Lower Cretaceous tight oil in Jiuquan Basin, NW China. Petroleum Exploration and Development 45, 227-238.Davudov, D., Moghanloo, R.G., Lan, Y., 2018. Evaluation of accessible porosity using mercury injection capillary pressure data in shale samples. Energy & Fuels 32, 4682-4694.Deng, B., Yin, G., Li, M., Zhang, D., Lu, J., Liu, Y., Chen, J., 2018. Feature of fractures induced by hydrofracturing treatment using water and L-CO2 as fracturing fluids in laboratory experiments. Fuel 226, 35-46.Dong, D., Shi, Z., Guang, Q., Jiang, S., Zhang, M., Zhang, C., Wang, S., Sun, S., Yu, R., Liu, D., Peng, P., Wang, S., 2018. Progress, challenges and prospects of shale gas exploration in the Wufeng–Longmaxi reservoirs in the Sichuan Basin. Natural Gas Industry 38, 67-76.Fianu, J., Gholinezhad, J., Hassan, M., 2018. Comparison of temperature-dependent gas adsorption models and their application to shale gas reservoirs. Energy & Fuels 32, 4763-4771.Gong, Y., Liu, K., Liu, S., 2018. Determining the occurrence of oil in micro/nanopores of tight sand: A new approach using environmental scanning electron microscopy combined with energy-dispersive spectrometry. Energy & Fuels 32, 4885-4893.Han, Y., Poetz, S., Mahlstedt, N., Karger, C., Horsfield, B., 2018. Fractionation of pyrrolic nitrogen compounds compounds during primary migration of petroleum within the Barnett Shale sequence of Marathon 1 Mesquite Well, Texas. Energy & Fuels 32, 4638-4650.Hao, Y., Yuan, L., Li, P., Zhao, W., Li, D., Lu, D., 2018. Molecular simulations of methane adsorption behavior in illite nanopores considering basal and edge surfaces. Energy & Fuels 32, 4783-4796.He, J., Wang, J., Yu, Q., Liu, W., Ge, X., Yang, P., Wang, Z., Lu, J., 2018. Pore structure of shale and its effects on gas storage and transmission capacity in well HD-1 eastern Sichuan Basin, China. Fuel 226, 709-720.Hu, Q., Liu, H., Li, M., Li, Z., Yang, R., Zhang, Y., Sun, M., 2018. Wettability, pore connectivity and fluid-tracer migration in shale oil reservoirs of Paleogene Shahejie Formation in Dongying sag of Bohai Bay Basin, East China. Acta Petrolei Sinica 39, 278-289.Kang, J., Sun, Y., Men, Y., Tian, J., Yu, Q., Yan, J., Lin, J., Liu, J., 2018. Shale gas enrichment conditions in the frontal margin of Dabashan orogenic belt, south China. Journal of Natural Gas Science and Engineering 54, 11-24.Kibria, M.G., Hu, Q., Liu, H., Zhang, Y., Kang, J., 2018. Pore structure, wettability, and spontaneous imbibition of Woodford Shale, Permian Basin, West Texas. Marine and Petroleum Geology 91, 735-748.Ko, L.T., Ruppel, S.C., Loucks, R.G., Hackley, P.C., Zhang, T., Shao, D., 2018. Pore-types and pore-network evolution in Upper Devonian-Lower Mississippian Woodford and Mississippian Barnett mudstones: Insights from laboratory thermal maturation and organic petrology. International Journal of Coal Geology 190, 3-28.Li, Y., Schieber, J., Fan, T., Wei, X., 2018. Pore characterization and shale facies analysis of the Ordovician-Silurian transition of northern Guizhou, South China: The controls of shale facies on pore distribution. Marine and Petroleum Geology 92, 697-718.Li, Z., Shen, X., Qi, Z., Hu, R., 2018. Study on the pore structure and fractal characteristics of marine and continental shale based on mercury porosimetry, N2 adsorption and NMR methods. Journal of Natural Gas Science and Engineering 53, 12-21.Li, Z., Sun, X., Wang, F., Liang, Y., 2018. Microscopic flow characteristics of fluids in porous medium and its relationship with remaining oil distribution: A case study in Saertu oilfield of Daqing in China. Geofluids 2018, Article 7549831.Lin, L., Yu, Y., Zhai, C., Li, Y., Wang, Y., Liu, G., Guo, Y., Gao, J., 2018. Paleogeography and shale development characteristics of the Late Permian Longtan Formation in southeastern Sichuan Basin, China. Marine and Petroleum Geology 95, 67-81.Liu, B., Qi, C., Mai, T., Zhang, J., Zhan, K., Zhang, Z., He, J., 2018. Competitive adsorption and diffusion of CH4/CO2 binary mixture within shale organic nanochannels. Journal of Natural Gas Science and Engineering 53, 329-336.Liu, K., Ostadhassan, M., Gentzis, T., Carvajal-Ortiz, H., Bubach, B., 2018. Characterization of geochemical properties and microstructures of the Bakken Shale in North Dakota. International Journal of Coal Geology 190, 84-98.Liu, K., Ostadhassan, M., Zou, J., Gentzis, T., Rezaee, R., Bubach, B., Carvajal-Ortiz, H., 2018. Nanopore structures of isolated kerogen and bulk shale in Bakken Formation. Fuel 226, 441-453.Sanguinito, S., Goodman, A., Tkach, M., Kutchko, B., Culp, J., Natesakhawat, S., Fazio, J., Fukai, I., Crandall, D., 2018. Quantifying dry supercritical CO2-induced changes of the Utica Shale. Fuel 226, 54-64.Sarkar, P., Kumar, A., Singh, K.H., Ghosh, R., Singh, T.N., 2018. Pore system, microstructure and porosity characterization of Gondwana shale of Eastern India using laboratory experiment and watershed image segmentation algorithm. Marine and Petroleum Geology 94, 246-260.Shi, M., Yu, B., Zhang, J., Huang, H., Yuan, Y., Li, B., 2018. Microstructural characterization of pores in marine shales of the Lower Silurian Longmaxi Formation, southeastern Sichuan Basin, China. Marine and Petroleum Geology 94, 166-178.Shi, Z., Qiu, Z., Dong, D., Lu, B., Liang, P., Zhang, M., 2018. Lamina characteristics of gas-bearing shale fine-grained sediment of the Silurian Longmaxi Formation of Well Wuxi 2 in Sichuan Basin, SW China. Petroleum Exploration and Development 45, 358-368.Su, A., Chen, H., Chen, X., He, C., Liu, H., Li, Q., Wang, C., 2018. The characteristics of low permeability reservoirs, gas origin, generation and charge in the central and western Xihu depression, East China Sea Basin. Journal of Natural Gas Science and Engineering 53, 94-109.Sun, B., Wang, J., Wang, Z., Gao, Y., Xu, J., 2018. Calculation of proppant-carrying flow in supercritical carbon dioxide fracturing fluid. Journal of Petroleum Science and Engineering 166, 420-432.Wang, J., Zhang, S., 2018. Pore structure differences of the extra-low permeability sandstone reservoirs and the causes of low resistivity oil layers: A case study of Block Yanwumao in the middle of Ordos Basin, NW China. Petroleum Exploration and Development 45, 273-280.Wang, P., Peng, S., He, T., 2018. A novel approach to total organic carbon content prediction in shale gas reservoirs with well logs data, Tonghua Basin, China. Journal of Natural Gas Science and Engineering 55, 1-15.Wang, X., Mou, C., Wang, Q., Zhou, K., Liang, W., Ge, X., Chen, X., 2018. Recomment on the study of lithofacies palaeogeography as a guide for geology survey of shale gas. Acta Sedimentologica Sinica 36, 215-231.Wu, H., Zhang, C., Ji, Y., Liu, R., Wu, H., Zhang, Y., Geng, Z., Zhang, Y., Yang, J., 2018. An improved method of characterizing the pore structure in tight oil reservoirs: Integrated NMR and constant-rate-controlled porosimetry data. Journal of Petroleum Science and Engineering 166, 778-796.Wu, L., Geng, A., Wang, P., 2018. Oil expulsion in marine shale and its influence on the evolution of nanopores during semi-closed pyrolysis. International Journal of Coal Geology 191, 125-134.Xu, M., Binazadeh, M., Zolfaghari, A., Dehghanpour, H., 2018. Effects of dissolved oxygen on water imbibition in gas shales. Energy & Fuels 32, 4695-4704.Yang, Y., Bao, F., 2017. Characteristics of shale nanopore system and its internal gas flow: A case study of the lower Silurian Longmaxi Formation shale from Sichuan Basin, China. Journal of Natural Gas Geoscience 2, 303-311.Zhang, T., He, Y., Yang, Y., Wu, K., 2017. Molecular simulation of shale gas adsorption in organic-matter nanopore. Journal of Natural Gas Geoscience 2, 323-332.Zou, C., Zhao, Q., Dong, D., Yang, Z., Qiu, Z., Liang, F., Wang, N., Huang, Y., Duan, A., Zhang, Q., Hu, Z., 2017. Geological characteristics, main challenges and future prospect of shale gas. Journal of Natural Gas Geoscience 2, 273-288.Zuo, J.Y., Guo, X., Liu, Y., Pan, S., Canas, J., Mullins, O.C., 2018. Impact of capillary pressure and nanopore confinement on phase behaviors of shale gas and oil. Energy & Fuels 32, 4705-4714.Yurchenko, I.A., Moldowan, J.M., Peters, K.E., Magoon, L.B., Graham, S.A., 2018. Source rock heterogeneity and migrated hydrocarbons in the Triassic Shublik Formation and their implication for unconventional resource evaluation in Arctic Alaska. Marine and Petroleum Geology 92, 932-952.AbstractsAbada, A., Segev, E., 2018. Multicellular features of phytoplankton. Frontiers in Marine Science 5, 144. doi: 10.3389/fmars.2018.00144. are microscopic photosynthesizing organisms that live in the sunlit layer of the ocean. They are of global importance, accounting for half of the primary productivity on Earth. Members of this group can undergo a programmed cell death process that has the hallmarks of apoptosis. The existence of apoptosis-like processes in phytoplankton raises the enigma of why single-celled organisms commit "suicide". Through our own work, and through interpretation of existing literature, we provide evidence suggesting that coccolithophores and diatoms, two key groups of phytoplankton, exhibit a multicellular-like state. These communities regularly aggregate, communicate and execute coordinated behaviors, which are traits that adhere to the core definition of multicellularity. If phytoplankton populations indeed exist in a multicellular-like organization, the benefits of apoptotic processes in phytoplankton could be studied in analogy to multicellular organisms. Given the central role of phytoplankton in many global scale processes, it is fascinating to think how these cells regularly exist in units of physically attached cells that potentially act semi-coherently across kilometer scale. In the bacterial world, our recognition of biofilms as multicellular arrangements furthered the study of bacterial communication and ecology. Similarly, we propose areas of research that would benefit from acknowledging the multicellular traits of phytoplankton. As our oceans become warmer, more stratified and more acidic, key communities of primary-producers are forced to rapidly adjust. Therefore, studying phytoplankton in a multicellular context would be significant in gaining a comprehensive view of phytoplankton physiology and ecology under changing conditions.Microscopic marine phytoplankton drift freely in the ocean, harvesting sunlight through photosynthesis. These unicellular microorganisms account for half of the primary productivity on Earth and play pivotal roles in the biogeochemistry of our planet (Field et al., 1998). The major groups of microalgae that comprise the phytoplankton community are coccolithophores, diatoms and dinoflagellates. In present oceans, phytoplankton individuals and populations are forced to rapidly adjust, as key chemical and physical parameters defining marine habitats are changing globally. Here we propose that microalgal populations often display the characteristics of a multicellular-like community rather than a random collection of individuals. Evolution of multicellularity entails a continuum of events starting from single cells that go through aggregation or clonal divisions (Brunet and King, 2017). Phytoplankton may be an intermediate state between single cells and aggregates of physically attached cells that communicate and co-operate; perhaps an evolutionary snapshot toward multicellularity. In this opinion article, we journey through several studies conducted in two key phytoplankton groups, coccolithophores and diatoms, to demonstrate how observations in these studies could be interpreted in a multicellular context.Emiliania huxleyi is the most widespread coccolithophore in modern oceans. Populations of this microalga form massive seasonal blooms that cover thousands of square kilometers and are easily detected by satellites (Holligan et al., 1983; Balch et al., 1991; Balch, 2018). The blooms exhibit unique dynamics whereby they form seasonally over several weeks and then suddenly collapse (Tyrrell and Merico, 2004; Behrenfeld and Boss, 2014; Lehahn et al., 2014). The sudden demise of these blooms is mostly attributed to viral infection (Bratbak et al., 1993; Vardi et al., 2012; Lehahn et al., 2014), and bacteria have also been shown to drive the sudden collapse of E. huxleyi populations (Segev et al., 2016). Algal death, whether due to biotic or abiotic factors, often bears much similarity to Programmed Cell Death (PCD), a process known from higher plants and animals (Bidle, 2016).PCD has also been reported in diatoms, a key group of phytoplankton. Diatoms are responsible for 50% of the global phytoplankton productivity (Rousseaux and Gregg, 2014). Diatoms, similarly to coccolithophores, grow rapidly over wide areas of ocean, forming blooms that suddenly terminate with death of the vast majority of the population. Autocatalytic death in diatoms was initially reported in response to nutrient limitation (Brussaard et al., 1997; Berges and Falkowski, 1998). Numerous studies have since provided a comprehensive view of the environmental triggers and molecular mechanisms underlying various death mechanisms in diatoms (Bidle, 2015, 2016).In multicellular organisms, PCD is a process that maintains proper growth and functionality of individuals (Hamburger and Levi-Montalcini, 1949; Glucksmann, 1951; Lockshin and Williams, 1964; Kerr et al., 1972; Milligan and Schwartz, 1996; Jones, 2001; Danial and Korsmeyer, 2004). PCD is an active and highly regulated process that can be undertaken by a subpopulation of cells that are infected or genetically perturbed, in order to eliminate the harmful influence and/or agent and save the other cells. It is considered to be an altruistic act executed by individual cells for the greater good of the entire organism (Glucksmann, 1951; Lockshin and Williams, 1964; Kerr et al., 1972; Milligan and Schwartz, 1996; Jones, 2001; Danial and Korsmeyer, 2004).Much research has been conducted in recent years to elucidate the eco-physiology of PCD in phytoplankton (Franklin et al., 2006; Bidle, 2015, 2016). While knowledge about mechanisms driving and controlling PCD in phytoplankton expands, it remains unclear why a unicellular organism would execute a highly controlled death process. The paradox of PCD in single-celled organisms has been previously raised and discussed (Ameisen, 1996, 2002; Franklin et al., 2006; Nedelcu et al., 2011; Bayles, 2014; Durand et al., 2016). It has been posited that PCD in single-celled organisms has a different origin and nature than in multicellular organisms (Nedelcu et al., 2011). In addition, it has been proposed that PCD can increase biological complexity in microbial communities (Durand et al., 2016). Faced with the puzzling nature of unicellular PCD, we offer several observations and highlight reports from the literature that encourage a reconsideration of the multicellular features of phytoplankton. We provide several lines of evidence demonstrating multicellular traits of phytoplankton and subsequently discuss the benefits of phytoplankton PCD in analogy to this process in multicellular organisms.To examine multicellular traits of phytoplankton, we sought to find a definition for multicellularity. Multicellularity has independently evolved at least 16 times within all domains of life (Bonner, 1998; King, 2004; Rokas, 2008; Knoll, 2011). Previous attempts to define multicellularity, especially in the microbial world, have delineated two essential parameters that must be met in a multicellular scenario: intercellular communication that leads to coordinated action, and cell-cell adhesion (Lyons and Kolter, 2015). In the next paragraphs we demonstrate modes of phytoplankton communication and cell-cell adhesion, and we discuss how phytoplankton PCD could be interpreted as a coordinated population action. While clearly phytoplankton cells exist as individual cells, we find ample reports suggesting that microalgae are frequently found as multicellular-like assemblages.Acemel, R.D., Govantes, F., Cuetos, A., 2018. Computer simulation study of early bacterial biofilm development. Scientific Reports 8, Article no.. 5340. bacteria form organized sessile communities, known as biofilms. Their ubiquity and relevance have stimulated the development of efficient mathematical models able to predict biofilm evolution and characteristics at different conditions. Here we present a study of the early stages of bacterial biofilm formation modeled by means of individual cell-based computer simulation. Simulation showed that clusters with different degrees of internal and orientational order were formed as a function of the aspect ratio of the individual particles and the relation between the diffusion and growth rates. Analysis of microscope images of early biofilm formation by the Gram-negative bacterium Pseudomonas putida at varying diffusion rates revealed a good qualitative agreement with the simulation results. Our model is a good predictor of microcolony morphology during early biofilm development, showing that the competition between diffusion and growth rates is a key aspect in the formation of stable biofilm microcolonies.Adrian, D.R., King, D.T., Jaret, S.J., Orm?, J., Petruny, L.W., Hagerty, J.J., Gaither, T.A., 2018. Sedimentological and petrographic analysis of drill core FC77‐1 from the flank of the central uplift, Flynn Creek impact structure, Tennessee. Meteoritics & Planetary Science 53, 857-873. Drill core FC77‐1 on the flank of the central uplift, Flynn Creek impact structure, Tennessee, contains 175?m of impact breccia lying upon uplifted Lower Paleozoic carbonate target stratigraphy. Sedimentological analysis of this 175‐m interval carbonate breccia shows that there are three distinct sedimentological units. In stratigraphic order, unit 1 (175–109?m) is an overall coarsening‐upward section, whereas the overlying unit 2 (109–32?m) is overall fining‐upward. Unit 3 (32–0?m) is a coarsening‐upward sequence that is truncated at the top by postimpact erosion. Units 1 and 3 are interpreted as debris or rock avalanches into finer sedimentary deposits within intracrater marine waters, thus producing progressively coarser, coarsening‐upward sequences. Unit 2 is interpreted to have formed by debris or rock avalanches into standing marine waters, thus forming sequential fining‐upward deposits. Line‐logging of clasts ranging from 5?mm to 1.6?m, and thin‐section analysis of selected drill core samples (including clasts < 5?mm), both show that the Flynn Creek impact breccia consists almost entirely of dolostone clasts (90%), with minor components of cryptocrystalline melt clasts, chert and shale fragments, and clastic grains. Cryptocrystalline melt clasts, which appear isotropic in thin section, are in fact made of exceedingly fine quartz crystals that exhibit micro‐Fourier transform infrared (FTIR) and micro‐Raman spectra consistent with crystalline quartz. These cryptocrystalline melt clasts are the first melt clasts of any kind to be reported from Flynn Creek impact structure.Afzali, S., Rezaei, N., Zendehboudi, S., 2018. A comprehensive review on Enhanced Oil Recovery by Water Alternating Gas (WAG) injection. Fuel 227, 218-246. (WAG) injection is a relatively mature oil recovery technique in hydrocarbon reservoirs that has long attracted the interest of the oil and gas industry due to its successful performance. The main goal of the WAG projects is to control the mobility and to decrease the problem of viscous fingering, leading to improved oil recovery by combining the benefits of Gas Injection (GI) and Waterflooding (WF). Implementation of a new EOR/IOR project requires a comprehensive knowledge of previous successful and failed experiences, and adequate understanding of the technical and non-technical aspects of the recovery process. This knowledge may be attained from reviewing similar projects that were reported in the literature. Despite great applications of the WAG injection in hydrocarbon reservoirs and extensive studies, the last comprehensive review goes back to 1998, focusing on the field applications only. There are a few review papers that are more updated; however, they are either dedicated to a particular aspect of the WAG (such as CO2 abnormalities), or applications in a specific geographical region (such as North Sea). An updated comprehensive study, covering recent experiences and lessons that are learnt from previous studies, seems to be imperative. This paper reviews the WAG theory, applications, governing mechanisms of fluid displacement and oil production from pore to field scale. It also addresses the most common challenges and operational problems along with the remedies during WAG projects. The effects of important variables such as reservoir properties, fluid properties, and operating conditions on the performance of WAG are studied from experimental, simulation and modeling, and pore-scale investigations.Ahmed, O.E., El Nady, M.M., Mahmoud, S.A., 2018. Assessment of polycyclic aromatic hydrocarbons of organic richness in seawater from some coastal area around Alexandria city, Egypt. Petroleum Science and Technology 36, 682-687. compositions of polycyclic aromatic hydrocarbons used as chemical markers for the identifying of different sources in the surface seawater of Alexandria coastal area. The quantitative analysis of polycyclic aromatic hydrocarbons (PAHs) showed a concentration ranged from 8970.939-1254756.00?ng/L, which exceed the maximum admissible concentrations of PAHs (200?ng/L) for the water standard of European Union. The calculated diagnostic ratios suggested that the sources of PAHs at the majority of the studied area are derived primarily from pyrogenic sources from incomplete fuel combustion of the boats and vehicle engines with lesser amounts of PAHs contributed from petrogenic sources. Some stations displayed mixed sources in comparison to many other studied marine systems, the PAHs concentrations detected at Alexandria area were considered be higher to pose health risks to aquatic bodies.Ait-Itto, F.-Z., Martinez, M., Price, G.D., Ait Addi, A., 2018. Synchronization of the astronomical time scales in the Early Toarcian: A link between anoxia, carbon-cycle perturbation, mass extinction and volcanism. Earth and Planetary Science Letters 493, 1-11. Late Pliensbachian–Early Toarcian is a pivotal time in the Mesozoic era, marked by pronounced carbon-isotope excursions, biotic crises and major climatic and oceanographic changes. Here we present new high-resolution carbon-isotope and magnetic-susceptibility measurements from an expanded hemipelagic Late Pliensbachian–Early Toarcian section from the Middle Atlas Basin (Morocco). Our new astronomical calibration allows the construction of an orbital time scale based on the 100-kyr eccentricity cycle. The Early Toarcian Polymorphum Zone contains 10 to 10.5 repetitions of the 100-kyr eccentricity both in the carbon-isotope and the magnetic-susceptibility data, leading to an average duration of 1.00 ± 0.08 myr. We also show that the Late Pliensbachian–Early Toarcian global carbon-cycle perturbation has an average duration of 0.24 ± 0.02 myr. These durations are comparable to previous astrochronological time scales provided for this time interval in the most complete sections of the Tethyan area, and longer than what has been provided in condensed sections. Anchoring this framework on published radiometric ages and astrochronological time scales, we estimate that the carbon-cycle perturbation of the Late Pliensbachian–Early Toarcian corresponds with the early phase of the Karoo and Chonke Aike large igneous provinces. Likewise, our new age constraints confirm that the Toarcian oceanic anoxic event is synchronous to the main phase of the Ferrar volcanic activity. Thus, these successive and short phases of the volcanic activity may have been at the origin of the successive phases of the mass extinctions observed in marine biotas in the Pliensbachian and Toarcian times.Akhondzadeh, H., Keshavarz, A., Sayyafzadeh, M., Kalantariasl, A., 2018. Investigating the relative impact of key reservoir parameters on performance of coalbed methane reservoirs by an efficient statistical approach. Journal of Natural Gas Science and Engineering 53, 416-428. complex and unique production mechanism of CBM has been examined extensively; however, production from such reservoirs requires more investigation to be well-understood, predicted and enhanced. This study is aimed at probing the significance of some controlling parameters on CBM performance by a statistical approach. The relative impact of five CBM reservoir parameters (reservoir pressure, cleat permeability and porosity, Young's modulus and Langmuir pressure) on the performance of natural depletion as well as Enhanced Coalbed Methane (ECBM) were numerically investigated. Recovery factor (RF) for primary depletion and ECBM, original gas in place (OGIP) and CO2 storage were the investigated responses. In order to conduct the research, a synthetic CBM reservoir model was constructed using a commercial reservoir simulator. Since the effects of reservoir parameters on CBM production are quite complicated, it was intended to explore the potential interaction effects between the parameters along with the relative impact of each parameter. Therefore, a professional statistical software, Design Expert, was selected to determine the parameters' effects. The results show that while recovery factor value in primary recovery has positive correlations with all of the five parameters, cleat permeability and Langmuir pressure play the most significant roles. For ECBM by CO2 injection, cleat permeability has the most significant effect on recovery factor measure, followed by cleat porosity. The predicted model for ECBM recovery factor suggests that Young's modulus, opposite to the primary recovery condition, has an adverse relationship with RF and the cleat porosity-permeability interaction has a considerable negative effect on RF measure. The predicted coalbed methane OGIP model proposes that in comparison with pressure and Langmuir pressure, the relative impacts of the other three parameters are negligible. Furthermore, results reveal that CO2 storage is positively affected by cleat porosity and permeability, and negatively affected by Young's modulus and Langmuir pressure.Akhtar, N., Akhtar, K., Ghauri, M.A., 2018. Biodesulfurization of thiophenic compounds by a 2-hydroxybiphenyl-resistant Gordonia sp. HS126-4N carrying dszABC genes. Current Microbiology 75, 597-603. can metabolize or transform a range of known chemical compounds present in fossil fuels by naturally having highly specific metabolic activities. In this context, the microbial desulfurization of fuels is an attractive and alternative process to the conventional hydrodesulfurization (HDS) process, since the thiophenic sulfur containing compounds such as dibenzothiophene (DBT) and benzothiophene (BT) cannot be removed by HDS. A DBT desulfurizing mesophilic bacterium, identified on the basis of 16S rRNA gene sequence as Gordonia sp. HS126-4N (source: periphery soil of a coal heap) has been evaluated for its biodesulfurization traits and potential to desulfurize the thiophenic compounds. The HPLC and LC/MS analyses of the metabolites produced from DBT desulfurization and PCR-based nucleotide sequence confirmation of the key desulfurizing genes (dszA/dszB/dszC) proved that HS126-4N could convert DBT to 2-hydroxybiphenyl (2-HBP) via the 4S pathway. The isolate could convert 0.2?mM of DBT to 2-HBP within 48?h and was reasonably tolerant against the inhibitory effect of 2-HBP (retained 70% of growth at 0.5?mM 2-HBP). The isolated biocatalyst desulfurized/degraded 100% of 0.2?mM of 4-methyl DBT, 2,8-dimethyl DBT, BT and 3-methyl BT within 108?h. The capabilities to survive and desulfurize a broad range of thiophenic sulfur containing substrates as well as less inhibition by the 2-HBP suggest that HS126-4N could be a potential candidate for improved biodesulfurization/organic sulfur removal from fossil fuels.Al-Khafaji, A.J., Hakimi, M.H., Najaf, A.A., 2018. Organic geochemistry characterisation of crude oils from Mishrif reservoir rocks in the southern Mesopotamian Basin, South Iraq: Implication for source input and paleoenvironmental conditions. Egyptian Journal of Petroleum 27, 117-130. crude oils from Cretaceous Mishrif reservoir rocks in the southern Mesopotamian Basin, South Iraq were studied to describe oil characteristics, providing information on the source of organic matter input and the genetic link between oils and their potential source rock in the basin. This study is based on biomarker and non-biomarker analyses performed on oil samples. The analysed oils are aromatic intermediate oils as indicated by high aromatic hydrocarbon fractions with more that 50%. These oils are also characterized by high sulfur and trace metal (Ni, V) contents and relatively low API gravity values (19.0–27.2° API). The results of this study indicate that these oils were derived from a marine carbonate source rocks bearing Type II-S kerogen that were deposited under sulphate-reducing conditions. This is primary achieved from their biomarkers and bulk carbon isotope and inorganic element contents (i.e., S, Ni and V). The absence of 18a (H)-oleanane biomarker also suggests a source age older than Late Cretaceous. The biomarker characteristics of these oils are consistent with those of the Late Jurassic to Early Cretaceous source rocks in the basin. However, biomarker maturity data also indicate that the oils were generated from early maturity source rocks. This appears to result from the type of kerogen of the source rock, characterized by a high-S kerogen (Type II-S).Al-Safran, E., 2018. Prediction of asphaltene precipitation risk in oil wells using coupled thermohydraulics model. Journal of Petroleum Science and Engineering 167, 329-342. precipitation and deposition is a major flow assurance challenge, which manifests itself in reservoir, production tubing, and flowline and process facility. Asphaltene may precipitate due to two main factors, namely high asphaltene content, and high difference between reservoir pressure and oil bubble-point pressure, i.e. precipitation driving force, even if asphaltene content is low. The objective of this study is to develop a predictive simulation tool to assess the risk of asphaltene precipitation in oil wells and to estimate the asphaltene risk window. Further objective is to use the developed simulation tool to generate well design and production scenarios to efficiently prevent, mitigate and manage asphaltene precipitation. A comprehensive asphaltene deposition workflow is developed to identify the major steps to enable a solution strategy. To implement the workflow, Ansari et al. (1994) mechanistic two-phase flow hydrodynamic model in vertical wells is coupled with two Asphaltene precipitation thermodynamic models, namely de Boer et al. (1995), and Wang et al. (2006). In this study, de-Boer et al. model is extended from a single point reservoir model to a multi-point wellbore model; while Wang et al. is used to predict and compare the asphaltene instability with live-oil instability along wellbore. The developed simulator was validated to predict the risk and depth window of asphaltene precipitation in Middle East oil wells, resulting in a reasonable agreement with the field data. In addition, the simulation tool is used to carry out a parametric study to investigate the impact of oil gravity, and reservoir pressure on asphaltene precipitation risk.Al Hamimi, S., Sandahl, M., Armeni, M., Turner, C., Spégel, P., 2018. Screening of stationary phase selectivities for global lipid profiling by ultrahigh performance supercritical fluid chromatography. Journal of Chromatography A 1548, 76-82. performance of seven sub-2-μm particle packed columns (2-picolylamine, 2-PIC; charged surface hybrid fluoro-phenyl, CSH-FP; high strength silica C18 SB, HSS-C18; diethylamine, DEA; 1-aminoanthracene, 1-AA; high density diol and ethylene bridged hybrid; BEH) was examined for lipid separation in ultra-high performance supercritical fluid chromatography (UHPSFC) coupled to quadrupole time-of-flight mass spectrometry. Based on the results of the column screening a method for profiling of multiple lipid species from the major lipid classes was developed.Stationary phases containing β-hydroxy amines, i.e. 1-AA, DEA and 2-PIC, yielded strong retention and poor peak shapes of zwitterionic lipids with primary amine groups, such as phosphatidylserines, phosphatidylethanolamines and its lyso forms. The BEH and HSS-C18 columns showed strong retention of polar and nonpolar lipids, respectively. The Diol column retained the majority of major lipid classes and also produced symmetric peaks. In addition, this column also produced the highest resolution within and between major lipid classes. An injection solvent composed of methanol:chloroform (1:2, v:v) and the addition of 20?mM ammonium formate in the mobile phase improved chromatographic separation and mass spectrometry detection in comparison to ammonium acetate or absence of additive. Finally, chromatographic and mass spectrometric parameters were optimized for the Diol column using a design of experiments approach. The separation mechanism on the Diol column depended on the lipid functionality and the length and degree of unsaturation of the acyl groups. The developed method could resolve 18 lipid classes and multiple lipids within each class, from blood serum and brain tissue in 11?min.Al Sultan, A., Zirrahi, M., Hassanzadeh, H., Abedi, J., 2018. Effect of the surfactant on asphaltene deposition on stainless-steel and glass surfaces. Energy & Fuels 32, 5635-5642. dispersants have been introduced as a proper candidate to mitigate the problems caused by asphaltene precipitation, such as clogging wells, flowlines, and surface facilities in oil industry. In this work, we study the effects of dodecylbenzenesulfonic acid (DBSA) as a surfactant on asphaltene deposition on stainless-steel and glass surfaces. Experiments were conducted to measure asphaltene precipitation in the bulk system and asphaltene deposition on the stainless-steel and glass surfaces. Results revealed that the surfactant delays the asphaltene onset in the bulk system. However, asphaltene deposition on the stainless-steel surface was increased at all measured concentrations of the surfactant, while the deposition rate on the glass surface decreased by increasing the surfactant concentration. Affinity of the surfactant molecules to the stainless-steel surface was verified in asphaltene deposition and removal tests. The results revealed that the DBSA surfactant is able to remove deposited asphaltene on glass surfaces at high concentrations. This study reveals the importance of surface properties when the surfactant is used as an asphaltene dispersant.Alagich, R., Gardeisen, A., Alonso, N., Rovira, N., Bogaard, A., 2018. Using stable isotopes and functional weed ecology to explore social differences in early urban contexts: The case of Lattara in mediterranean France. Journal of Archaeological Science 93, 135-149. stable isotope investigation of plant and animal ecology can shed new light on the practicalities and politics of land management. Ecological analysis of archaeobotanical weed flora offers a complementary approach to arable growing conditions. Here we introduce the first combined study of stable isotope compositions (carbon and nitrogen) of plant and faunal remains and functional weed ecology from mediterranean France in order to investigate agricultural strategies under urbanisation and their social implications. Animal bones and charred crops and weeds are investigated from two archaeologically distinct residential areas from 5th century BCE Lattara, zones 1 and 27, during a period characterised by significant urban expansion in the region. Plant carbon and nitrogen isotope composition and functional weed ecology suggest some differences in growing conditions between crops found in the two zones, zone 27 being associated with more intensively cultivated crops than zone 1, where extensive cultivation, which can achieve much greater surplus, was dominant. These findings coincide with archaeological evidence of a ‘richer’ variety of material culture and foodstuffs in zone 1. Carbon and nitrogen isotopic values of animal bone collagen suggest that the main domesticates from both zones consumed a similar diet; however, rabbits exhibit a difference, with those from zone 1 having significantly higher δ15N, implying that the two zones sourced this species differently.Alfarge, D., Wei, M., Bai, B., 2018. CO2-EOR mechanisms in huff-n-puff operations in shale oil reservoirs based on history matching results. Fuel 226, 112-120. Oil Recovery (IOR) techniques in Unconventional Liquids Rich Reservoirs (ULR) are still a new concept because there is no commercial project for any IOR technique so far. Carbon dioxide (CO2) based EOR technique has been effectively applied to improve oil recovery in the tight formations of conventional reservoirs. Extending this approach to unconventional formations has been extensively investigated over the last decade because CO2 has unique properties which make it the first option of EOR methods to be tried. However, the applications and mechanisms for CO2-EOR in unconventional reservoirs would not necessarily be the same as in conventional reservoirs due to the complex and poor-quality properties of these plays.Since the first CO2-EOR huff-n-puff project was conducted in conventional reservoirs in Trinidad and Tobago in 1984, more than 130 additional projects have been put in operation around the world, mainly located in USA, Turkey, and Trinidad and Tobago. In this study, we combined Production Data Analysis (PDA) for the production data of these projects with numerical simulation methods to produce one typical graph accounts for the main mechanisms controlling CO2-EOR performance in conventional reservoirs. On the other hand, we have couple of CO2-EOR huff-n-puff pilot tests conducted in Bakken formation between 2008 and 2016. Two engineering-reversed approaches have been integrated to produce a unique type curve for the performance of CO2-EOR huff-n-puff process in shale oil reservoirs. Firstly, a numerical simulation study was conducted to upscale the reported experimental-studies outcomes to the field conditions. As a result, different forward diagnostic plots have been generated from different combinations for CO2 physical mechanisms with different shale-reservoirs conditions. Secondly, different backward diagnostic plots have been produced from the history match with CO2 performances in fields’ pilots performed in some portions of Bakken formation located in North Dakota and Montana. Finally, fitting the backward with the forward diagnostic plots was used to produce another unique type curve to represent CO2-EOR performance in shale oil reservoirs. This study found that the delayed response in the incremental oil production resulted from CO2 injection in shale reservoirs is mainly function of CO2 molecular diffusion mechanism. On the other hand, the CO2 diffusion mechanism has approximately no effect on CO2-EOR performance in conventional reservoirs which have a quick response to CO2 injection. This finding is very well consistent with the experimental reports regarding the role of diffusion in conventional cores versus shale cores. In addition, this study found that kinetics of oil recovery process in productive areas and CO2-diffusivity level are the keys to perform a successful CO2-EOR project in shale formations. This paper provides a thorough idea about how CO2-EOR performance is different in the field scale of conventional reservoirs versus shale formations.Alizadeh, B., Maroufi, K., Fajrak, M., 2018. Hydrocarbon reserves of Gachsaran oilfield, SW Iran: Geochemical characteristics and origin. Marine and Petroleum Geology 92, 308-318. and carbon isotope data were used to depict geochemical properties and to delineate source of the crude oils from Asmari and Bangestan reservoirs of the giant Gachsaran oilfield, SW Iran. Despite the distinct horizons of the reservoirs and severe petrophysical heterogeneity inside each reservoir, all oil samples show an identical level of thermal maturity. Furthermore, similar source-related parameters reflect identical source rock for both reservoirs. They indicate carbonate-marl source deposited in a marine environment under anoxic-suboxic conditions. Strong marine organic matter signatures of predominantly algal origin along with evidence of a terrigenous angiosperm plant contribution were detected. Geochemical evidence suggests that the Gachsaran field Asmari and Bangestan oils being sourced from a mix of organic-rich Kazhdumi and Pabdeh source rocks of Albian and Middle Eocene-Early Oligocene ages, respectively. Carbon isotope composition and V/Ni ratio signatures indicate Kazhdumi Formation as the main source rock. Meanwhile, significant presence of oleanane and less than unity values of C29/C30 hopanes ratio demonstrate a partial contribution of Pabdeh Formation. This contradiction could be explained by two scenarios; 1) incorporating very immature non-expelled Pabdeh oils into the mature Kazhdumi oils during migration or 2) partial charge form low maturity Pabdeh oils that is insufficient to impact a typical mixed signature over the geochemical fingerprint of the reservoired oils. Additionally, geochemical similarities give rise to an assumption of reservoir and trap inter-connection for this giant field.Amrollahi Biyouki, A., Hosseinpour, N., Nassar, N.N., 2018. Pyrolysis and oxidation of asphaltene-born coke-like residue formed onto in situ prepared NiO nanoparticles toward advanced in situ combustion enhanced oil recovery processes. Energy & Fuels 32, 5033-5044. and oxidation of asphaltene-born coke-like residue formed onto ex situ and in situ prepared NiO nanoparticles as initial steps toward developing advanced in situ combustion enhanced oil recovery (EOR) processes were studied. The in situ synthesized NiO nanoparticles in heavy oil matrix, containing coke-like residue, were characterized by X-ray diffraction, Brunauer–Emmett–Teller, field-emission scanning electron microscopy, and energy-dispersive X-ray mapping techniques. The pyrolysis and postpyrolysis oxidation of the coke residue were investigated by temperature-programmed pyrolysis (TPP) and temperature-programmed oxidation (TPO) methods, respectively. Oxidation kinetics of the coke residue was described by the Kissinger–Akahira–Sunose isoconversional method. The results showed a higher percentage of coke residue on the in situ prepared nanoparticles than the ex situ employed ones. Eventually, during the TPP of the coke residue, the amount of carbon oxides released per total amount of the coke is 18.6% higher for the in situ NiO as compared to the ex situ NiO nanoparticles. This may be attributed to the uniform dispersion of the in situ NiO in the coke residue. Furthermore, compared to the ex situ NiO, the in situ NiO nanoparticles shift the oxidation temperature of the coke residue by about 100 °C to lower temperature. Multistep kinetics was predicted with a significant drop of the activation energy of the oxidation of the coke residue in the presence of in situ and ex situ NiO nanoparticles, confirming their catalytic effect. However, the pre-exponential factor, as a representation of the collision efficiency, is significantly higher over the in situ NiO compared to the ex situ NiO, leading to the enhanced oxidation of the coke residue. This may be attributed to the loss of surface area due to particle aggregation for the case of ex situ preparation, as well as the orientation of asphaltene molecules during the adsorption onto the surface. The asphaltenes could be aligned mostly vertically over the in situ NiO surface; thus the vertical alignment provides good channels for diffusion of gas-phase oxygen onto the surface leading to high collision efficiency and catalytic activity.Andersen, O., Nilsen, H.M., 2018. Investigating simplified modeling choices for numerical simulation of CO2 storage with thermal effects. International Journal of Greenhouse Gas Control 72, 49-64. is a key variable for the modeling of geological CO2 storage, and any simulation model must take it explicitly or implicitly into account. At the large spatial scales and low flow rates associated with CO2 migration studies, temperature can be reasonably considered as an constant and imposed external field, with CO2 and brine assumed to be in thermal equilibrium with the surrounding rock. Closer to an injection well, the picture is different. CO2 may be injected at a temperature significantly different from that of the aquifer, leading to an expanding thermal front around the injection well. The local change in temperature not only affects fluid properties, but also geomechanical stresses and the rate of geochemical reactions.In this article, we examine whether certain simplified approaches used to simulate CO2 storage at the large scale may be adapted and applied to model the regions affected by the thermal front. We do this by comparing the results from upscaled (vertically integrated) flow models extended with heat transport and different choices of overburden representations against highly resolved 3D models. The considered test cases have been constructed to minimize or maximize specific characteristics of the coupled flow-thermal system: the Peclet number, the gravity number and the amount of thermal bleed.Our results suggest that for several practical cases the thermal front can be reasonably well modeled using a vertically integrated flow model with constant vertical temperature. The results also suggest that a simplified overburden representation may give a reasonable approximation, particularly for scenarios with low thermal bleed. We point out that the impact of a simplified overburden representation can be very similar to the use of linear heat transfer coefficients. On the other hand, while models that completely neglect thermal bleed may perform acceptably in some low-bleed settings, they often lead to very large errors.Anthony, I.G.M., Brantley, M.R., Gaw, C.A., Floyd, A.R., Solouki, T., 2018. Vacuum ultraviolet spectroscopy and mass spectrometry: A tandem detection approach for improved identification of gas chromatography-eluting compounds. Analytical Chemistry 90, 4878-4885. wide class characterizations of volatile organic compounds (VOCs), conventional gas chromatography mass spectrometry (GC-MS)-based techniques are utilized. These GC-MS-based chemical identification approaches typically rely on library searches against ion fragmentation patterns of known compounds. Although MS library searches can often provide correct chemical identities, erroneous chemical assignments of structurally similar unknown compounds are also possible. Other detection systems, such as absorption spectrometers, have been used for VOC analysis and can provide complementary absorption data. Here, we demonstrate the analytical advantages of coupling vacuum ultraviolet (VUV) absorption spectroscopy and MS in tandem for the improved characterization of structurally similar VOCs. We also discuss technical considerations and limitations of coupling a VUV spectrometer to a quadrupole mass spectrometer. Moreover, we show that combining the isomer selectivity of VUV spectroscopy, as a nondestructive analyte detection approach, with the mass selectivity of MS in a VUV-MS detection system improves characterization of GC-eluting compounds. Utilizing GC/VUV-MS data, we demonstrate that orthogonal VUV and MS library searches improve identification of VOCs present in complex mixtures such as a mixed standard sample, a commercial perfume product, and an essential oil sample.Aoyama, S., Nishizawa, M., Miyazaki, J., Shibuya, T., Ueno, Y., Takai, K., 2018. Recycled Archean sulfur in the mantle wedge of the Mariana Forearc and microbial sulfate reduction within an extremely alkaline serpentine seamount. Earth and Planetary Science Letters 491, 109-120. identification of microbial activity under extreme conditions is important to define potential boundaries of the habitable and uninhabitable zones of terrestrial and extraterrestrial living forms. The subseafloor regimes of serpentinite seamounts in the Mariana Forearc are among the most extreme environments for life on earth owing to the widespread presence of highly alkaline fluids with pH values greater than 12. The potential activity of sulfate-reducing microorganisms has been suggested within the South Chamorro serpentinite seamounts on the basis of depletion of sulfate and enrichment of dissolved sulfide in pore water. However, the vertical distribution of sulfate-reducing microorganisms and the origin of sulfate are still uncertain. To address these issues, we analyzed quadruple sulfur isotopes of sulfide minerals and pore water sulfate in the upper 56 m of sedimentary sequences at the summit of the S. Chamorro Seamount and those of dissolved sulfate in upwelling fluids collected as deep as 202 mbsf (meters below the seafloor) in a cased hole near the summit of the same seamount. The depth profiles of the concentrations and the δ34S and Δ33S′ values of sulfide minerals and pore water sulfate indicate microbial sulfate reduction as deep as 30 mbsf. Further, apparent isotopic fractionations (ε34) and exponents of mass dependent relationships (33λ) during sulfate reduction are estimated to be 62 ± 14‰ and 0.512 ± 0.002, respectively. The upwelling fluids show both the chlorine depletion relative to seawater and the negative δ15N values of ammonia (?4‰). Although these signatures point to dehydration of the subducting oceanic plate, the negative Δ33S′ values of sulfate (?0.16‰ to ?0.26‰ with analytical errors of ±0.01‰) are unlikely to originate from surrounding modern crusts. Instead, sulfate in the upwelling fluid likely possess non-mass-dependent (NMD) sulfur. Because NMD sulfur was produced primarily in the Archean atmosphere, our results suggest that the presence of recycled Archean crust that could be incorporated into the upper mantle through subduction of Archean oceanic crusts or from the NMD-bearing OIB seamounts located in the southern margin of the Pacific Plate.Apel, N., Uliyanchenko, E., Moyses, S., Rommens, S., Wold, C., Macko, T., Brüll, R., 2018. Separation of branched poly(bisphenol a carbonate) structures by solvent gradient at near-critical conditions and two-dimensional liquid chromatography. Analytical Chemistry 90, 5422-5429. is a molecular metric that strongly influences the application properties of polymers. Consequently, detailed information on the microstructure is required to gain a deeper understanding of structure–property relationships. In the present case, we employ high-performance liquid chromatography to characterize the branching in a poly(bisphenol A carbonate) (PC). To this end, a method was developed based on a mobile phase gradient in a very narrow range (±1.4 vol %) around the point of adsorption (98.9/1.1 vol % chloroform/methyl tert-butyl ether), which we refer to as solvent gradient at near-critical conditions. Application of such gentle gradient enabled separation of PC according to end-groups. The separation mechanism was confirmed by collecting fractions of a separated sample and subsequently analyzing these by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Hyphenating the developed gradient method with size-exclusion chromatography as the second dimension (2D-LC) enabled separation of linear and branched PC chains and determination of the molar mass distribution of the fractions. A reversed elution order was observed for branched species in 2D-LC, meaning that low molar mass chains exhibited higher elution volumes in the first dimension than higher molar masses. This finding was explained by influences of end-groups as well as the architecture of the branched polymer chains.Araie, H., Nakamura, H., Toney, J.L., Haig, H.A., Plancq, J., Shiratori, T., Leavitt, P.R., Seki, O., Ishida, K.-i., Sawada, K., Suzuki, I., Shiraiwa, Y., 2018. Novel alkenone-producing strains of genus Isochrysis (Haptophyta) isolated from Canadian saline lakes show temperature sensitivity of alkenones and alkenoates. Organic Geochemistry 121, 89-103. species have been recently found in diverse lacustrine environments, albeit with taxonomic information derived indirectly from environmental genomic techniques. In this study, we isolated alkenone-producing algal species from Canadian saline lakes and established unialgal cultures of individual strains to identify their taxonomical and molecular biological characteristics. Water and sediments collected from the lakes were first enriched in artificial seawater medium over a range of salinities (5–40 g/L) to cultivate taxa in vitro. Unialgal cultures of seven haptophyte strains were isolated and categorized in the Isochrysis clade using SSU and LSU rRNA gene analysis. The alkenone distributions within isolated strains were determined to be novel compared with other previously reported alkenone-producing haptophytes. While all strains produced the typical C37 and C38 range of isomers, one strain isolated from Canadian salt lakes also produced novel C41 and C42 alkenones that are temperature sensitive. In addition, we showed that all alkenone unsaturation indices (e.g., U37K and U37K′) are temperature-dependent in culture experiments, and that alkenoate indices (e.g., U37A, U38A, RIA38 and A37/A38) provide alternative options for temperature calibration based on these new lacustrine algal strains. Importantly, these indices show temperature dependence in culture experiments at temperatures below 10?°C, where traditional alkenone proxies were not as sensitive. We hypothesize that this suite of calibrations may be used for reconstructions of past water temperature in a broad range of lakes in the Canadian prairies.Araujo, J., Pratihary, A., Naik, R., Naik, H., Naqvi, S.W.A., 2018. Benthic fluxes of methane along the salinity gradient of a tropical monsoonal estuary: Implications for CH4 supersaturation and emission. Marine Chemistry 202, 73-85. in the Mandovi estuary, a typical tropical monsoonal estuary located on the west coast of India, revealed that waters were perennially supersaturated with CH4, indicating that the estuary could be a significant emitter of this greenhouse gas. In order to test the hypothesis that the estuarine sediments serve as a major source of CH4 to the overlying water column, a series of intact core incubations were carried out at three sites along the salinity (S) gradient of the estuary during the summer (May–June) of 2014. The three sites - off Betim, Amona and Ganjem - represented different salinity regimes (33, 18 and 1, respectively). The benthic CH4 fluxes exhibited a progressive increasing trend from 4.71?μmol?m?2?d?1 at the marine end (S?>?20) to 16.01?μmol?m?2?d?1 in the brackish water zone (20?≥?S?≥?5) and 93.90?μmol?m?2?d?1 at the freshwater end (S?<?5). The total benthic flux of CH4 from the Mandovi estuary was computed to be 9.79?×?106?g?y?1. The observed upstream increasing trend may be controlled by a combination of salinity, sedimentary Corg and sediment cohesiveness. High rates of CH4 oxidation (10–1364?μmol?m?2?d?1) were observed at all the sites with an increasing trend upstream indicating salinity control on methanotrophy. Despite high methanotrophic activity at the sediment-water interface, the net benthic CH4 release to the water column still remained significant, accounting for high CH4 supersaturation of the estuarine water and making the estuary a potential CH4 source to the atmosphere. Our results imply that during the monsoon (wet) season, the total area integrated benthic CH4 flux may be even higher as the entire estuary becomes freshwater dominated.Ardakani, O.H., Sanei, H., Ghanizadeh, A., Lavoie, D., Chen, Z., Clarkson, C.R., 2018. Do all fractions of organic matter contribute equally in shale porosity? A case study from Upper Ordovician Utica Shale, southern Quebec, Canada. Marine and Petroleum Geology 92, 794-808. many unconventional hydrocarbon systems, organic matter (OM) substantially contributes to total porosity of the rock that led to a positive correlation between total organic carbon (TOC) and porosity. While organic porosity is an important reservoir property of unconventional hydrocarbon systems, TOC of these rocks consists of different macerals or petrographic fractions. These TOC fractions can be geochemically divided and quantified by the revised, extended slow heating (ESH) Rock-Eval analysis. This study discusses the contribution of different fractions of OM on porosity variation in the mature to overmature Utica Shale in southern Quebec, using ESH Rock-Eval analysis, helium pycnometery, scanning electron microscopy (SEM), and X-ray diffraction (XRD) mineralogy. Selected samples from three wells at depths of ～400, 700, and 2000 m, covering a range of thermal maturity from late peak oil window (VRoeqv. ～1%) to dry gas zone (VRoeqv. ～2.1%) were analyzed in this study. The predominant OM constituents are solid bitumen, chitinozoans, and minor graptolites with mean TOC of 1.1 ± 0.4 wt. %. The mean porosity for oil and gas window samples decreases with depth from 3.9 ± 0.9 to 2.6 ± 0.5%, respectively. The SEM images reveal that organic porosity is limited to pores developed in solid bitumen, while regardless of thermal maturity, chitinozoans have a non-porous structure throughout the oil to dry gas window. This observation suggests that the impact of thermal maturity on porosity is different for different OM fractions (i.e., macerals), leading to different contribution of OM fractions to total porosity. The latter conclusion is further supported by the improved correlation observed between the solid bitumen fraction and porosity compared to TOC-porosity correlation for oil window samples.Our entire data set suggests that OM (i.e., bitumen fraction), especially in the dry gas window, is not the major controlling factor on the total porosity in the Utica Shale, whereas, intergranular porosity has the dominant control on total porosity. This observation suggests that the hydrocarbon storage potential may largely reside in inorganic pores rather than organic pores in the analyzed intervals of the Utica Shale. The decrease in total porosity observed from shallower samples (i.e., oil window) to deeper samples (i.e., dry gas window) also suggests that intergranular porosity is the dominant porosity component, which decreases with burial.Arias-Ortiz, A., Masqué, P., Garcia-Orellana, J., Serrano, O., Mazarrasa, I., Marbà, N., Lovelock, C.E., Lavery, P., Duarte, C.M., 2018. Reviews and syntheses: 210Pb-derived sediment and carbon accumulation rates in vegetated coastal ecosystems: setting the record straight. Biogeosciences Discussions 2018, 1-47. coastal ecosystems, including tidal marsh, mangrove and seagrass, are being increasingly assessed for their potential in carbon dioxide sequestration worldwide. However, there is a paucity of studies that have effectively estimated the accumulation rates of sediment organic carbon (Corg) beyond the mere quantification of Corg stocks. Here, we discuss the use of the 210Pb dating technique as a practical tool to measure the rate of Corg accumulation in vegetated coastal ecosystems. We critically review the status of 210Pb dating methods of vegetated coastal sediments and assess the limitations that apply to these ecosystems, which are often composed by heterogeneous sediments, abundant in coarse particles, with varying inputs of organic material, and are disturbed by natural and anthropogenic processes causing sediment mixing, changes in sedimentation rates or erosion. Through a range of simulations, we discuss the most relevant processes that impact the 210Pb record in vegetated coastal ecosystems and evaluate the deviations in sediment and Corg accumulation rates produced by anomalies in 210Pb profiles. Our results show that the deviation in the determination of sediment and derived Corg accumulation rates is within 20?% confirming that the 210Pb dating technique is secure. However, while these uncertainties might be acceptable for the determination of mean sediment and Corg accumulation rates over the last century, they may not always allow the determination of a detailed geochronology, historical reconstruction, or to ascertain rates of change and fluxes. Additional tracers or geochemical data need to be used in concert to constrain the 210Pb-derived results and to properly interpret the processes recorded in vegetated coastal sediments. The framework provided in this study can be instrumental in reducing the uncertainties associated to the estimates of Corg accumulation rates in vegetated coastal sediments.Armstrong, D.L., Lancet, D., Zidovetzki, R., 2018. Replication of simulated prebiotic amphiphilic vesicles in a finite environment exhibits complex behavior that includes high progeny variability and competition. Astrobiology 18, 419-430. studied the simulated replication and growth of prebiotic vesicles composed of 140 phospholipids and cholesterol using our R-GARD (Real Graded Autocatalysis Replication Domain) formalism that utilizes currently extant lipids that have known rate constants of lipid-vesicle interactions from published experimental data. R-GARD normally modifies kinetic parameters of lipid-vesicle interactions based on vesicle composition and properties. Our original R-GARD model tracked the growth and division of one vesicle at a time in an environment with unlimited lipids at a constant concentration. We explore here a modified model where vesicles compete for a finite supply of lipids. We observed that vesicles exhibit complex behavior including initial fast unrestricted growth, followed by intervesicle competition for diminishing resources, then a second growth burst driven by better-adapted vesicles, and ending with a final steady state. Furthermore, in simulations without kinetic parameter modifications (“invariant kinetics”), the initial replication was an order of magnitude slower, and vesicles' composition variability at the final steady state was much lower. The complex kinetic behavior was not observed either in the previously published R-GARD simulations or in additional simulations presented here with only one lipid component. This demonstrates that both a finite environment (inducing selection) and multiple components (providing variation for selection to act upon) are crucial for portraying evolution-like behavior. Such properties can improve survival in a changing environment by increasing the ability of early protocellular entities to respond to rapid environmental fluctuations likely present during abiogenesis both on Earth and possibly on other planets. This in silico simulation predicts that a relatively simple in vitro chemical system containing only lipid molecules might exhibit properties that are relevant to prebiotic processes. Asaadian, H., Zanbouri, H., Soulgani, B.S., 2018. Bitumen-water interfacial tension modeling by using subtractive clustering method. Petroleum Science and Technology 36, 765-771. of interfacial tension during bitumen production is a crucial issue in heavy crude oil history. Upon variation in pressure, temperature and phases composition, interfacial tension between bitumen and water change. In this work a sophisticated method called subtractive clustering was utilized to predict dynamic interfacial tension between bitumen and water. The subtractive clustering method is composed of optimized fuzzy logic algorithm. A data bank which is collected from open-source literature, is used to create a reliable model. Then the prediction accuracy of the measured dynamic interfacial tension using subtractive clustering have been examined. Results state that the comparison of measured interfacial tension and predicted interfacial tension indicate acceptable accuracy of proposed model. Also more than 90 percent of data points have less than 3 percent absolute error.Asghar, M.A., Zhu, Q., Sun, S., Peng, Y.e., Shuai, Q., 2018. Suspect screening and target quantification of human pharmaceutical residues in the surface water of Wuhan, China, using UHPLC-Q-Orbitrap HRMS. Science of The Total Environment 635, 828-837. this study we developed a systematic method for suspect screening and target quantification of the human pharmaceutical residues in water, via solid phase extraction (SPE) followed by liquid chromatography-high resolution mass spectrometry (LC-HRMS). We then proceeded to study the occurrences and distribution of the pharmaceuticals in the surface waters of Wuhan, China, by analyzing water samples from lakes, rivers and municipal sewage. Initially, 33 human pharmaceuticals were identified from East Lake without using purchasing standards. Of these, 29 were later confirmed by using standards, and quantified using the aforementioned SPE pretreatment method and LC-HRMS analysis in full MS scan mode. The 29 compounds included 8 antibiotics, 9 metabolites, and 12 miscellaneous pharmaceuticals. The highest proportions of pharmaceutical residues were detected downstream of the Yangtze River and in the lakes close to the central city. Metformin, cotinine, and trans-3-hydroxy cotinine, were frequently encountered in all the surface water samples. High concentrations (&gt;120?ng/l) of caffeine, metformin, theobromine, and valsartan were detected in the surface water samples; the removal rates of these compounds in the municipal sewage treatment plant were also high. In contrast, although the concentrations of 4-AAA and metoprolol acid in the surface water were high, the removal rates of these residues in the sewage treatment plant were low.Baatsen, M., von der Heydt, A.S., Huber, M., Kliphuis, M.A., Bijl, P.K., Sluijs, A., Dijkstra, H.A., 2018. Equilibrium state and sensitivity of the simulated middle-to-late Eocene climate. Climate of the Past Discussions 2018, 1-49. the early Eocene has been considered in many modelling studies, detailed simulations of the middle and late Eocene climate are currently scarce. To understand Antarctic glaciation at the Eocene-Oligocene Transition (~?34?Ma) as well as middle Eocene warmth, it is vital to have an adequate reconstruction of the middle-to-late Eocene climate. Here, we present a set of high resolution coupled climate simulations using the Community Earth System Model (CESM) version 1. Two middle-to-late Eocene cases are considered with new detailed 38?Ma geographical boundary conditions with a different radiative forcing. With 4?× pre-industrial concentrations of CO2 (i.e. 1120?ppm) and CH4 (~?2700?ppb), the equilibrium sea surface temperatures correspond well to available late middle Eocene (42–38?Ma) proxies. Being generally cooler, the simulated climate with 2?× pre-industrial values is a good analog for that of the late Eocene (38–34?Ma). Deep water formation occurs in the South Pacific Ocean, while the North Atlantic is strongly stratified and virtually stagnant. A shallow and weak circumpolar current is present in the Southern Ocean with only minor effects on southward oceanic heat transport within wind-driven gyres. Terrestrial temperature proxies, although limited in coverage, also indicate that the results presented here are realistic. The reconstructed 38?Ma climate has a reduced equator-to-pole temperature gradient and a more symmetric meridional heat distribution compared to the pre-industrial reference. Climate sensitivity is similar (~?0.7?°C/Wm2) to that of the present-day climate (~?0.8?°C/Wm2; 3?°C per CO2 doubling), with significant polar amplification despite very limited sea ice and snow cover. High latitudes are mainly kept warm by albedo and cloud feedbacks in combination with global changes in geography and the absence of polar ice sheets. The integrated effect of geography, vegetation and ice accounts for a 6–7?°C offset between pre-industrial and 38?Ma Eocene boundary conditions. These 38?Ma simulations effectively show that a realistic middle-to-late Eocene climate can be reconstructed without the need for greenhouse gas concentrations much higher than proxy estimates. The general circulation and radiative budget allow for mild high-latitude regions and little to no snow and ice cover, without making equatorial regions extremely warm.Babi?, I., Mucko, M., Petri?, I., Bosak, S., Mihanovi?, H., Vilibi?, I., Dup?i? Radi?, I., Cetini?, I., Cecilia, B., Raffaella, C., Ljube?i?, Z., 2018. Multilayer approach for characterization of bacterial diversity in a marginal sea: From surface to seabed. Journal of Marine Systems 184, 15-27. are the most important microorganisms in the world oceans, accounting for up to 75% of the total biomass. They are responsible for fundamental biogeochemical processes and therefore often used as ecological indicators. In this study, bacteria were quantified by flow cytometry and their diversity assessed by High Throughput Sequencing (HTS) in the southern Adriatic Sea. The most abundant bacterial groups were also quantified by qPCR. The samples were collected from the surface to the seabed over a total of 16 different depths at four stations during the late winter BIOTA (BIO-Tracing Adriatic water masses) cruise conducted in March 2016. The investigated area showed unusual water mass properties and was characterized by a shallow mixed layer, which differed from the usual winter convection conditions, typical of middle-altitude ecosystems and important for the seasonal picoplankton dynamics of this area. Heterotrophic bacteria were separated into HNA (relative High Nucleic Acid content) and LNA (Low Nucleic Acid content) subpopulations with abundances up to 1.8?×?105 and 8.8?×?105?cells?mL?1, respectively. HNA dominated at offshore stations reaching their maximum at depths below the euphotic zone. The bacterial community was dominated by Alphaproteobacteria, accounting for >40% of the total sequence reads and were mainly represented by the SAR11 clade (90.84%), followed by Marinimicrobia (18% of the total sequence reads), mainly represented by clade SAR406 (8.44%). Distinctive bacterial groups were found in the euphotic layer (Bacteroidetes and Actinobacteria) and aphotic layer samples (Deltaproteobacteria, Marinimicrobia, Chloroflexi, Acidobacteria and Planctomycetes). Results of the qPCR analyses further confirmed HTS results with highest abundances obtained for Alphaproteobacteria, followed by Gammaproteobacteria and Bacteroidetes. The adopted multiple approach, combining different molecular tools, critically supported by optics and flow cytometry, reveal changes in the bacterial assemblages during the unusual thermohaline conditions observed in 2016 in the southern Adriatic Sea.Baczynski, A.A., Polissar, P.J., Juchelka, D., Schwieters, J., Hilkert, A., Summons, R.E., Freeman, K.H., 2018. Picomolar‐scale compound‐specific isotope analyses. Rapid Communications in Mass Spectrometry 32, 730-738.: We report modifications to compound‐specific isotope analyses (CSIA) to enable high‐precision isotopic analyses of picomoles of carbon for intact organic molecules. This sample size is two orders of magnitude below the amounts required for commercial systems. The greatly enhanced sensitivity of this system expands molecular isotope studies and applications previously prohibited by low concentrations and small samples. Methods: We utilize the resolving power and low volumetric flow rates of narrow‐bore capillary gas chromatography to improve sample transfer efficiency while maintaining narrow peak widths. Post‐column peak broadening is minimized using a micro‐fluidic valve for solvent diversion, capillary combustion reactor, narrow‐bore capillary transfer lines, and cryogenic water trap. The mass spectrometer was fitted with collector amplifiers configured to 25 ms response times and a data logger board with firmware capable of rapid data acquisition. Carbon dioxide gas was introduced directly into the ion source to evaluate the dynamic range of the system and accuracy and precision of carbon isotope ratio (δ13C value) measurements. The accuracy and precision for combusted compounds were evaluated using a suite of n‐alkanes. Results: For ≥30 pmol carbon introduced directly into the ion source, the mean difference between the measured and expected δ13C values is 0.03‰ (1σ, n = 57) and the standard deviation of replicate measurements is 0.11‰ (1σ). The CO2 peak widths generated by the exponential dilution flask were 250 ms and the peak widths produced by combusting n‐alkanes were ca 500 ms, less than 25% the width of conventional gas chromatography peaks. For a mixture of 15 n‐alkanes (n‐C16 to n‐C30), the accuracy is 0.3‰ (1σ) and precision is 0.9‰ (1σ) for replicate δ13C measurements with 100 pmol carbon per compound on column. Conclusions: The pico‐CSIA method described here offers improved chromatographic resolution and reduces sample size requirements by two orders of magnitude. These advances significantly broaden the available analytical window for CSIA in research areas frequently hindered by sample size limitations, such as forensics, paleoclimate, astrobiology, and biochemistry. Baert, M., Martens, S., Desmet, G., de Villiers, A., Du Prez, F., Lynen, F., 2018. Enhancing the possibilities of comprehensive two-dimensional liquid chromatography through hyphenation of purely aqueous temperature-responsive and reversed-phase liquid chromatography. Analytical Chemistry 90, 4961-4967. two-dimensional liquid chromatography (LC × LC) allows for substantial gains in theoretical peak capacity in the field of liquid chromatography. However, in practice, theoretical performance is rarely achieved due to a combination of undersampling, orthogonality, and refocusing issues prevalent in many LC × LC applications. This is intricately linked to the column dimensions, flow rates, and mobile-phase compositions used, where, in many cases, incompatible or strong solvents are introduced in the second-dimension (2D) column, leading to peak broadening and the need for more complex interfacing approaches. In this contribution, the combination of temperature-responsive (TR) and reversed-phase (RP) LC is demonstrated, which, due to the purely aqueous mobile phase used in TRLC, allows for complete and more generic refocusing of organic solutes prior to the second-dimension RP separation using a conventional 10-port valve interface. Thus far, this was only possible when combining other purely aqueous modes such as ion exchange or gel filtration chromatography with RPLC, techniques which are limited to the analysis of charged or high MW solutes, respectively. This novel TRLC × RPLC combination relaxes undersampling constraints and complete refocusing and therefore offers novel possibilities in the field of LC × LC including temperature modulation. The concept is illustrated through the TRLC × RPLC analysis of mixtures of neutral organic solutes.Bagherpour, B., Bucher, H., Schneebeli-Hermann, E., Vennemann, T., Chiaradia, M., Shen, S.-z., 2018. Early Late Permian coupled carbon and strontium isotope chemostratigraphy from South China: Extended Emeishan volcanism? Gondwana Research 58, 58-70. isotope compositions of carbonates (δ13Ccarb) document a new 3.5‰ CIE toward lower values concomitant with an Emeishan Large Igneous Province (ELIP)-related drowning event (Mapojiao Event, southern Guizhou) during the early Wuchiapingian. Organic carbon isotope data (δ13Corg) have a 2‰ shift toward higher values across the drowning event, showing decoupling with the δ13Ccarb evolution. Rock-Eval and palynofacies analyses suggest an elevated flux of terrestrial organic matter (OM) during the drowning episode. Therefore, the decoupling between δ13Ccarb and δ13Corg is best explained by the mixing of different organic carbon pools in the δ13Corg curve. Strontium isotope data (87Sr/86Sr) also show a transient shift from 0.70715 to 0.70694 associated with this early Wuchiapingian carbon isotope excursion (CIE), which is superimposed on the late Permian prolonged global rising trend. This short-lived 87Sr/86Sr excursion is best interpreted as an enhanced hydrothermal flux related to a short pulse of ELIP-related parison of the Mapojiao Event with other C isotope records from South China and other parts of Tethys reveals substantial discrepancies. Moreover, older Capitanian CIEs concomitant with ELIP-related drownings are also not laterally reproducible in time. The local distribution of CIEs across Guadalupian-Lopingian (G-L) interval indicates the influence of local factors such as bathymetry and increased burial rate of terrestrial OM, rather than perturbations in the global carbon cycle to due volcanism. This prevents the C isotope record to be used as a global correlation tool during Capitanian and Wuchiapingian times. Comparison of palaeobiodiversity changes with perturbations in C isotope compositions across the G-L interval shows that only the oldest CIE was associated with a modest extinction event as documented in South China. Hence, this study undermines any systematic coupling and causal relation between extinctions and iterative perturbations of the C isotope record during the G-L interval.Bai, Q., Wei, H., Jiang, Z., Qiu, Z., 2018. The relationship between carbon isotopic changes and the sediments supply at the P-T boundary in Dongling Section, Jiangxi Province. Acta Sedimentologica Sinica 36, 267-279. largest mass extinction event in the Phanerozoic took place at the end of Permian. The cause of this biological crisis is still remaining controversial. This work uses the carbon isotope, major and minor elements across the Permian-Triassic boundary at the Dongling section in the Xiushui city of the Jiangxi Province to study the relationship between the global carbon cycle perturbation and consistent provenance changes and the mass extinction. The results show that the carbonate carbon isotope profile displays stepwise negative excursion. The magnitudes of first and secondary stepwise are 2‰ and 2.5‰, respectively, with a total magnitude of 4.5‰. In the process of stepwise negative excursion of carbon isotope,the provenance of silicate composition in the carbonate rock changes from mafic igneous rocks to island arc intermediate-acid igneous rocks. The later probably concern with the volcanic eruption of Southern China Island. According to negative excursion of carbon isotope has the same time with the change of provenance and ash layer, conjecture it may relate to South China island arc volcanism and volcanism eruption of Siberian large igneous provinces. Large-scale volcanism eruption released or triggered carbon dioxides and methane. These greenhouse gases and the global regression probably are the main causes for this stepwise carbon isotopic excursion across the Permian-Triassic boundary. The deteriorated environments resulted from the volcanism, e.g., global warming, marine anoxia, marine acidification, large sediment influx resulted from vegetation deterioration, lead to the increased pressure of organism existence and thus the mass extinction.Baker, A., Routh, J., Roychoudhury, A.N., 2018. n-Alkan-2-one biomarkers as a proxy for palaeoclimate reconstruction in the Mfabeni fen, South Africa. Organic Geochemistry 120, 75-85. sub-tropical Mfabeni fen is the only continuous coastal peat deposit that documents glacial and interglacial palaeoenvironmental conditions since the late Pleistocene (ca. 47?cal kyr BP) in southern Africa. Published bulk geochemical, biomarker and leaf wax δ13C data, along with palynology and stratigraphic studies of the Mfabeni peat sequence, render it an ideal record for testing new palaeoreconstruction proxies. In this study, we aimed to establish the proxy potential of n-alkan-2-one (n-ket) compounds by tracing their source/origin and post-depositional diagenetic change, and if they preserve or not a robust palaeoenvironment signal that complements our understanding of palaeoclimatic variations. In the Mfabeni archive the most likely source for n-kets is via microbial decarboxylation of n?+?1-alkanoic acids (n-FAs) and, to a lesser degree, oxidation of same chain length n-alkanes (n-alks). The n-ket average chain length (ACLket) and n-C23 and C25ket/precursor ratios displayed a statistical significant negative relationship with the n-alk aquatic plant proxy (Paq), suggesting the source of n-kets to be submerged aquatic plants during waterlogged conditions that suppressed microbial activity during the ensuing anoxic conditions. Both the mid-chain and long chain n-ket/precursor ratios displayed predominant water level fluctuation controls, with temperature as a secondary regulator. By comparing the n-ket data with published environmental and climate reconstructions from the same core, and with geomorphology and palynological studies of the Mfabeni basin, we conclude that the n-kets show promise as a palaeoclimate proxy and can be used in conjunction with other biomarker proxies to reconstruct ancient hydrological changes in sub-tropical peatlands.Bakker, R.J., 2018. AqSo_NaCl: Computer program to calculate p-T-V-x properties in the H2O-NaCl fluid system applied to fluid inclusion research and pore fluid calculation. Computers & Geosciences 115, 122-133. program AqSo_NaCl has been developed to calculate pressure - molar volume - temperature - composition (p-V-T-x) properties, enthalpy and heat capacity of the binary H2O-NaCl system. The algorithms are designed in BASIC within the Xojo programming environment, and can be operated as stand-alone project with Macintosh-, Windows-, and Unix-based operating systems. A series of ten self-instructive interfaces (modules) are developed to calculate fluid inclusion properties and pore fluid properties. The modules may be used to calculate properties of pure NaCl, the halite-liquidus, the halite-vapourus, dew-point and bubble-point curves (liquid-vapour), critical point, and SLV solid-liquid-vapour curves at temperatures above 0.1?°C (with halite) and below 0.1?°C (with ice or hydrohalite). Isochores of homogeneous fluids and unmixed fluids in a closed system can be calculated and exported to a.txt file. Isochores calculated for fluid inclusions can be corrected according to the volumetric properties of quartz. Microthermometric data, i.e. dissolution temperatures and homogenization temperatures, can be used to calculated bulk fluid properties of fluid inclusions. Alternatively, in the absence of total homogenization temperature the volume fraction of the liquid phase in fluid inclusions can be used to obtain bulk properties.Balascio, N.L., D'Andrea, W.J., Anderson, R.S., Wickler, S., 2018. Influence of vegetation type on n-alkane composition and hydrogen isotope values from a high latitude ombrotrophic bog. Organic Geochemistry 121, 48-57. composition and hydrogen isotope values of leaf wax components can be powerful tools in reconstructing past climate and environments. However, interpretation of past environmental conditions from such components in sediments is complicated by species-specific influences and there is a need to better understand how vegetation type affects leaf wax composition and isotope ratios in modern environments. In this study we analyzed leaf wax (n-alkane) distributions and hydrogen isotope values of plants from a high latitude ombrotrophic bog in northern Norway. The isotopic analysis of surface water was also conducted on samples from 15 lakes along a ca. 150?km transect to contextualize the bog water isotopic composition and constrain fractionation factors among n-alkane homologues. We identified 14 different plant types growing on the bog surface, including mosses, graminoids and other herbs, sub-shrubs and a tree. n-Alkanes from the leaves of the modern plants had average chain lengths from 25 to 30.5, with a variety of distributions, and with the dominant compound of longer chain lengths (C27, C29, or C31). δD values of n-C25 to n-C33 for the vegetation samples ranged from ?197‰ to ?116‰, with an average of ?162‰. The data also revealed that the δD values for the homologues for half of the vegetation types had ranges that were ≥20‰. Using the average isotopic value of bog water samples, ?60‰, we calculated apparent fractionation factors that ranged from ?66‰ to ?134‰ (avg. ??108?±?22‰), similar to other sites across Europe and to a global data compilation. Our results demonstrate the range of species-specific influences on leaf wax composition and isotopic values at this site and presumably other ombrotrophic bog environments, and provide a dataset to help evaluate the influence of vegetation type on regional sedimentary leaf wax records.Baludikay, B.K., Fran?ois, C., Sforna, M.C., Beghin, J., Cornet, Y., Storme, J.-Y., Fagel, N., Fontaine, F., Littke, R., Baudet, D., Delvaux, D., Javaux, E.J., 2018. Raman microspectroscopy, bitumen reflectance and illite crystallinity scale: comparison of different geothermometry methods on fossiliferous Proterozoic sedimentary basins (DR Congo, Mauritania and Australia). International Journal of Coal Geology 191, 80-94. rocks containing microfossils are crucial archives to reconstitute early life evolution on Earth. However, the preservation of microfossils within rocks depends on several physico-chemical factors. Among these factors, the thermal evolution of the host rocks can be decisive. Here, we investigated carbonaceous shale samples containing exquisitely preserved organic-walled microfossils assemblages from three Proterozoic shallow marine sedimentary sequences: the Mbuji-Mayi Supergroup (Democratic Republic of Congo, Congo Basin), the Atar/El Mre?ti Group (Mauritania, Taoudeni Basin) and the Kanpa Formation (Australia, Officer Basin). Thermal maturity of these rock samples is evaluated with Raman geothermometry, Raman reflectance, solid bitumen reflectance, illite crystallinity and Thermal Alteration Index. The comparison of results coming from these different techniques validates the use of Raman reflectance on Proterozoic carbonaceous material and especially for poorly-ordered carbonaceous material. We show that extracted kerogen (microfossils and amorphous organic material) is more accurate to estimate the thermal maturity of low-grade temperature Proterozoic sequences than kerogen in thin section. All techniques provide consistent range of temperatures except for Raman geothermometry, giving slightly higher estimates. Raman reflectance appears to be a fast, robust and non-destructive tool to evaluate the thermal maturity of poorly-organized carbonaceous material from Proterozoic rocks.Barker, A., Dombrosky, J., Venables, B., Wolverton, S., 2018. Taphonomy and negative results: An integrated approach to ceramic-bound protein residue analysis. Journal of Archaeological Science 94, 32-43. the growing body of evidence demonstrating that proteins can survive for thousands to even millions of years in selected contexts, there are relatively few examples of the successful recovery and identification of archaeological protein residues from ceramic artifacts. Claims of positive results are sometimes contentious and frequently challenged. One source of confusion in the debate is a general lack of consideration for the taphonomic histories of ceramic-bound proteins. To gain insight into this issue, we conducted an integrated, mass spectrometry-based study examining ceramic-bound protein that was experimentally aged over the course of 12 months. Results demonstrate the rapid degradation of proteins, raise questions about the degree to which ceramic-bound proteins can be expected to survive over time, and reveal some of the limitations of non-targeted mass spectrometry-based analyses. Further, by comparing results from our experimentally-aged samples to the those we obtained from a multi-pronged study of archaeological ceramics from the American Southwest, we are able to draw more confident conclusions regarding our lack of meaningful matches in the archaeological samples.Basuri, P., Sarkar, D., Paramasivam, G., Pradeep, T., 2018. Detection of hydrocarbons by laser assisted paper spray ionization mass spectrometry (LAPSI MS). Analytical Chemistry 90, 4663-4668. we introduce a new ambient ionization technique named laser assisted paper spray ionization mass spectrometry (LAPSI MS). In it, a 532 ± 10 nm, ≤10 mW laser pointer was shone on a triangularly cut paper along with high voltage, to effect ionization. The analyte solution was continuously pushed through a fused silica capillary, using a syringe pump, at a preferred infusion rate. LAPSI MS promises enhanced ionization with high signal intensity of polycyclic aromatic hydrocarbons (PAHs), which are normally not ionizable with similar ionization methods involving solvent sprays. LAPSI MS works both in positive and negative modes of ionization. A clear enhancement of signal intensity was visualized in the total ion chronogram for most analytes in the presence of the laser. We speculate that the mechanism of ionization is field assisted photoionization. The field-induced distortion of the potential well can be large in paper spray as the fibers comprising the paper are separated at tens of nanometers apart, and consequently, the analyte molecules are subjected to very large electric fields of the order of 107 Vcm–1. Ionization occurs from their distorted electronic states of reduced ionization energy, using the laser. Negative ion detection is also demonstrated, occurring due to the capture of produced photoelectrons. LAPSI MS can be used for monitoring in situ photoassisted reactions like the decarboxylation of mercaptobenzoic acid in the presence of gold and silver nanoparticles and the dehydrogenation reaction of 2,3-dihydro-1H-isoindole, which were chosen as examples. As an application, we have shown that paraffin oil, which is usually nonionizable by paper spray or by electrospray ionization can be efficiently detected using this technique. Impurities like mineral oils were detected easily in commercially available coconut oil, pointing the way to applications of social relevance.Bazvand, M., Farhangian, H., Najaflou, P., 2018. Comparison of several methods for obtaining hydrate formation pressure. Petroleum Science and Technology 36, 801-806. petroleum engineering hydrate is referred to as crystalline and snow like compounds Which consists of the capture of gaseous molecules among water molecules. The primary requirement for the prevention of hydrate is to recognize the conditions for its formation. Hydrate formation conditions include the presence of water, small gas molecules and the appropriate conditions of temperature and pressure. Several models have been proposed to determine the hydration pressure and temperature. Van der waals-platteeuw is a model base on statistical thermodynamics. In this model, the determinant is the fugacity of the gas phase. In this paper, the fugacity is obtained with different equations of state and replaced by the pattern provided by Parish and Prasnitz, to obtain the pressure and temperature of hydrate formation. In the end, results are compared with laboratory data and results from the CSMHyd Software and the experimental data to Check the accuracy of the model.Bea, S.A., Su, D., Mayer, K.U., MacQuarrie, K.T.B., 2018. Evaluation of the potential for dissolved oxygen ingress into deep sedimentary basins during a glaciation event. Geofluids 2018, Article 9475741. conditions in intracratonic sedimentary basins are currently reducing, even at relatively shallow depths. However, during glaciation-deglaciation events, glacial meltwater production may result in enhanced recharge (Bea et al., 2011; and Bea et al., 2016) potentially having high concentrations of dissolved oxygen (O2). In this study, the reactive transport code Par-MIN3P-THCm was used to perform an informed, illustrative set of simulations assessing the depth of penetration of low salinity, O2-rich, subglacial recharge. Simulation results indicate that the large-scale basin hydrostratigraphy, in combination with the presence of dense brines at depth, results in low groundwater velocities during glacial meltwater infiltration, restricting the vertical ingress of dilute recharge waters. Furthermore, several geochemical attenuation mechanisms exist for O2, which is consumed by reactions with reduced mineral phases and solid organic matter (SOM). The modeling showed that effective oxidative mineral dissolution rates and SOM oxidation rates between 5 × 10?15 and 6 × 10?13?mol?dm?3?bulk?s?1 were sufficient to restrict the depth of O2 ingress to less than 200?m. These effective rates are low and thus conservative, in comparison to rates reported in the literature. Additional simulations with more realistic, yet still conservative, parameters reaffirm the limited ability for O2 to penetrate into sedimentary basin rocks during a glaciation-deglaciation event.Beale, D.J., Crosswell, J., Karpe, A.V., Metcalfe, S.S., Morrison, P.D., Staley, C., Ahmed, W., Sadowsky, M.J., Palombo, E.A., Steven, A.D.L., 2018. Seasonal metabolic analysis of marine sediments collected from Moreton Bay in South East Queensland, Australia, using a multi-omics-based approach. Science of The Total Environment 631–632, 1328-1341. effects of urban density have altered natural ecosystems. Such changes include eutrophication of freshwater and adjoining coastal habitats, and increased levels of inorganic nutrients and pollutants into waterways. In Australia, these changes are intensified by large-scale ocean-atmospheric events, leading to considerable abiotic stress on the natural flora and fauna. Bacterial communities in marine sediments from Moreton Bay (South East Queensland, Australia) were examined in order to assess the impact of rainfall changes, chemical pollution, and subsequent abiotic stress on living organisms within a marine ecosystem. Sediments were collected during the wet and dry seasons and analyzed using bacterial metagenomics and community metabolomics techniques. Physicochemical data were also analyzed to account for biological variance that may be due to non-rainfall-based abiotic stresses. Wet-dry seasonality was the dominant control on bacterial community structure and metabolic function. Changes in the availability of nutrients, organic matter and light appeared to be the major seasonal stressors. In contrast, urban and industrial pollutants appeared to be minor stressors at the sites sampled. During the wet season, the bacterial community composition reflected organisms that utilize biogeochemical pathways with fast kinetics, such as aerobic metabolism, direct assimilation of inorganic compounds, and primary production. The transition to the dry season saw the bacterial community composition shift towards organisms that utilize more complex organic energy sources, such as carbohydrates and fatty acids, and anaerobic redox processes.Beik, I., Gómez, V.G., Podlaha, O.G., Mutterlose, J., 2018. The δ13C record of Maastrichtian-Paleocene oil shales from Jordan – Stratigraphic and environmental implications for an epicontinental setting. Journal of African Earth Sciences 143, 134-144. matter (OM) rich marls were deposited in several intrashelf basins in Jordan (e.g. Yarmouk Basin, Lajjun Basin, Azraq-Hamza Basin, Jafr Basin, Eshidiyya Basin) on the southeastern Tethyan margin during the Maastrichtian to middle Eocene. Factors like surface water productivity fueled by upwelling and sea level changes affected their deposition. Potential effects of climatic changes have not been determined yet.We present the first stable carbon and oxygen isotope records of Maastrichtian-Danian oil shales from the Azraq-Hamza and Jafr Basins in south- and central-east Jordan. The δ13Ccarb curves were time-calibrated based on calcareous nannofossil biostratigraphy. Eight notable excursions were identified in the Jordanian Maastrichtian sections. These were correlated with the documented Maastrichtian δ13Ccarb events in the (sub) tropical sections of Italy and the western Pacific: the Campanian-Maastrichtian boundary Events 4 and 5 (CMBE-4, CMBE-5), the Middle Maastrichtian Events 1 to 3 (MME-1 to MME-3) and the Cretaceous-Paleogene boundary Events 1 to 3 (KPgE-1 to KPgE-3). Signs of the Latest Danian Event (LDE) were recognized as well. Total organic carbon (TOC) data exhibit a complex relationship with the δ13Ccarb proxy record. The δ13Ccarb signals are repeatedly dampened due to the OM oxidation and subsequent 12C release. The effect of short term climate changes is observed, but is not always straight forward. Long term climate changes had indirect effects on bottom water oxygenation and OM preservation via sea level changes. The δ18Ocarb data from both sections reveal minor temperature changes in the Maastrichtian. Slight warming is observed in the MME interval. A potential increase of the paleotemperature is reported from the Azraq-Hamza section occurring in the latest Maastrichtian to earliest Danian.Belin, B.J., Busset, N., Giraud, E., Molinaro, A., Silipo, A., Newman, D.K., 2018. Hopanoid lipids: from membranes to plant–bacteria interactions. Nature Reviews Microbiology 16, 304-315. research represents a frontier for microbiology, as showcased by hopanoid lipids. Hopanoids, which resemble sterols and are found in the membranes of diverse bacteria, have left an extensive molecular fossil record. They were first discovered by petroleum geologists. Today, hopanoid-producing bacteria remain abundant in various ecosystems, such as the rhizosphere. Recently, great progress has been made in our understanding of hopanoid biosynthesis, facilitated in part by technical advances in lipid identification and quantification. A variety of genetically tractable, hopanoid-producing bacteria have been cultured, and tools to manipulate hopanoid biosynthesis and detect hopanoids are improving. However, we still have much to learn regarding how hopanoid production is regulated, how hopanoids act biophysically and biochemically, and how their production affects bacterial interactions with other organisms, such as plants. The study of hopanoids thus offers rich opportunities for discovery.Bell, E., Blake, L.I., Sherry, A., Head, I.M., Hubert, C.R.J., 2018. Distribution of thermophilic endospores in a temperate estuary indicate that dispersal history structures sediment microbial communities. Environmental Microbiology 20, 1134-1147. of thermophilic bacteria are found in cold and temperate sediments where they persist in a dormant state. As inactive endospores that cannot grow at the low ambient temperatures, they are akin to tracer particles in cold sediments, unaffected by factors normally governing microbial biogeography (e.g., selection, drift, mutation). This makes thermophilic endospores ideal model organisms for studying microbial biogeography since their spatial distribution can be directly related to their dispersal history. To assess dispersal histories of estuarine bacteria, thermophilic endospores were enriched from sediments along a freshwater‐to‐marine transect of the River Tyne in high temperature incubations (50°C). Dispersal histories for 75 different taxa indicated that the majority of estuarine endospores were of terrestrial origin; most closely related to bacteria from warm habitats associated with industrial activity. A subset of the taxa detected were marine derived, with close relatives from hot deep marine biosphere habitats. These patterns are consistent with the sources of sediment in the River Tyne being predominantly terrestrial in origin. The results point to microbial communities in estuarine and marine sediments being structured by bi‐directional currents, terrestrial run‐off and industrial effluent as vectors of passive dispersal and immigration.Beller, H.R., Rodrigues, A.V., Zargar, K., Wu, Y.-W., Saini, A.K., Saville, R.M., Pereira, J.H., Adams, P.D., Tringe, S.G., Petzold, C.J., Keasling, J.D., 2018. Discovery of enzymes for toluene synthesis from anoxic microbial communities. Nature Chemical Biology 14, 451-457. toluene biosynthesis was reported in anoxic lake sediments more than three decades ago, but the enzyme catalyzing this biochemically challenging reaction has never been identified. Here we report the toluene-producing enzyme PhdB, a glycyl radical enzyme of bacterial origin that catalyzes phenylacetate decarboxylation, and its cognate activating enzyme PhdA, a radical S-adenosylmethionine enzyme, discovered in two distinct anoxic microbial communities that produce toluene. The unconventional process of enzyme discovery from a complex microbial community (>300,000 genes), rather than from a microbial isolate, involved metagenomics- and metaproteomics-enabled biochemistry, as well as in vitro confirmation of activity with recombinant enzymes. This work expands the known catalytic range of glycyl radical enzymes (only seven reaction types had been characterized previously) and aromatic-hydrocarbon-producing enzymes, and will enable first-time biochemical synthesis of an aromatic fuel hydrocarbon from renewable resources, such as lignocellulosic biomass, rather than from?petroleum.Belles, A., Franke, C., Alary, C., Aminot, Y., Readman James, W., 2018. Understanding and predicting the diffusivity of organic compounds in polydimethylsiloxane material for passive sampler applications using a simple quantitative structure–property relationship model. Environmental Toxicology and Chemistry 37, 1291-1300. diffusivity of 145 compounds in polydimethylsiloxane (PDMS) material was determined in the laboratory using a film stacking technique. The results were pooled with available literature data, providing a final data set of 198 compounds with diffusivity (DPDMS) spanning over approximately 5 log units. The principal variables controlling the diffusivity of penetrants were investigated by comparing DPDMS within and between different homologous series. The dipole moment, molecular size, and flexibility of penetrants appear to be the most prevalent factors controlling a compound's diffusivity. A nonlinear quantitative structure–property relationship is proposed using as predicting variables the molecular volume, the number of rotatable bonds, the topological polar surface area, and the number of O and N atoms. The final relationship has a correlation coefficient of R2?=?0.81 and a mean absolute error of 0.26 m2 s?1 (log unit), approaching the average error for the experimentally determined values (0.12?m2 s?1). The model, based on a heuristic approach, is ready for use by analytical chemists with no specific background in theoretical chemistry (notably for passive sampler development).Benjamin, A., Slocombe, K., 2018. ‘Who’s a good boy?!’ Dogs prefer naturalistic dog-directed speech. Animal Cognition 21, 353–364. speech (IDS) is a?special speech register thought to aid language acquisition and improve affiliation in human infants. Although IDS shares some of its properties with dog-directed speech (DDS), it is unclear whether the production of DDS is functional, or simply an overgeneralisation of IDS within Western cultures. One recent study found that, while puppies attended more to a script read with DDS compared with adult-directed speech (ADS), adult dogs displayed no preference. In contrast, using naturalistic speech and a more ecologically valid set-up, we found that adult dogs attended to and showed more affiliative behaviour towards a speaker of DDS than of ADS. To explore whether this preference for DDS was modulated by the dog-specific words typically used in DDS, the acoustic features (prosody) of DDS or a combination of the two, we conducted a second experiment. Here the stimuli from experiment 1 were produced with reversed prosody, meaning the prosody and content of ADS and DDS were mismatched. The results revealed no significant effect of speech type, or content, suggesting that it is maybe the combination of the acoustic properties and the dog-related content of DDS that modulates the preference shown for naturalistic DDS. Overall, the results of this study suggest that naturalistic DDS, comprising of both dog-directed prosody and dog-relevant content words, improves dogs’ attention and may strengthen the affiliative bond between humans and their pets.Betancourt, S.S., Johansen, Y.B., Forsythe, J.C., Rinna, J., Christoffersen, K., Skillingstad, P., Achourov, V., Canas, J., Chen, L., Pomerantz, A.E., Zuo, J.Y., Mullins, O.C., 2018. Gravitational gradient of asphaltene molecules in an oilfield reservoir with light oil. Energy & Fuels 32, 4911-4924. toluene, asphaltenes are dispersed as molecules at low concentrations, as nanoaggregates at moderate concentrations, and as clusters of nanoaggregates at high concentrations. These three asphaltene species are codified in the Yen–Mullins model. For reservoir crude oils, equilibrated asphaltene gradients can be modeled with the Flory–Huggins–Zuo equation of state?(EoS). The gravity term and other terms depend on the particle sizes of the asphaltenes which are given in the Yen–Mullins model; these different asphaltene species (molecular and two nanocolloidal species) have been identified in gravity gradients in various reservoir studies. Here, the asphaltene gradient in a large reservoir is examined and found to be consistent with a molecular dispersion of asphaltenes in the crude oil. A variety of fluid and reservoir properties are evaluated to ensure validity of the analysis, particularly of thermodynamic equilibrium of the reservoir fluid. For crude oil samples throughout the reservoir, downhole fluid analysis (DFA), gas chromatography (GC), and two-dimensional gas chromatography (GC×GC) with cubic EoS and geochemical interpretation are consistent with fluid equilibration. Pressure measurement and production results are also consistent with fluid equilibration. This analysis is applicable to other reservoirs; molecular dispersions of asphaltenes are expected for other light oil reservoirs.Bhattarai, S., Cassarini, C., Rene, E.R., Zhang, Y., Esposito, G., Lens, P.N.L., 2018. Enrichment of sulfate reducing anaerobic methane oxidizing community dominated by ANME-1 from Ginsburg Mud Volcano (Gulf of Cadiz) sediment in a biotrickling filter. Bioresource Technology 259, 433-441. study was performed to enrich anaerobic methane-oxidizing archaea (ANME) present in sediment from the Ginsburg Mud Volcano (Gulf of Cadiz) in a polyurethane foam packed biotrickling filter (BTF). The BTF was operated at 20 (±2) °C, ambient pressure with continuous supply of methane for 248?days. Sulfate reduction with simultaneous sulfide production (accumulating ～7?mM) after 200?days of BTF operation evidenced anaerobic oxidation of methane (AOM) coupled to sulfate reduction. High-throughput sequence analysis of 16S rRNA genes showed that after 248?days of BTF operation, the ANME clades enriched to more than 50% of the archaeal sequences, including ANME-1b (40.3%) and ANME-2 (10.0%). Enrichment of the AOM community was beneficial to Desulfobacteraceae, which increased from 0.2% to 1.8%. Both the inoculum and the BTF enrichment contained large populations of anaerobic sulfur oxidizing bacteria, suggesting extensive sulfur cycling in the BTF.Bianchi, D., Weber, T.S., Kiko, R., Deutsch, C., 2018. Global niche of marine anaerobic metabolisms expanded by particle microenvironments. Nature Geoscience 11, 263-268. ocean waters, anaerobic microbial respiration should be confined to the anoxic waters found in coastal regions and tropical oxygen minimum zones, where it is energetically favourable. However, recent molecular and geochemical evidence has pointed to a much broader distribution of denitrifying and sulfate-reducing microbes. Anaerobic metabolisms are thought to thrive in microenvironments that develop inside sinking organic aggregates, but the global distribution and geochemical significance of these microenvironments is poorly understood. Here, we develop a new size-resolved particle model to predict anaerobic respiration from aggregate properties and seawater chemistry. Constrained by observations of the size spectrum of sinking particles, the model predicts that denitrification and sulfate reduction can be sustained throughout vast, hypoxic expanses of the ocean, and could explain the trace metal enrichment observed in particles due to sulfide precipitation. Globally, the expansion of the anaerobic niche due to particle microenvironments doubles the rate of water column denitrification compared with estimates based on anoxic zones alone, and changes the sensitivity of the marine nitrogen cycle to deoxygenation in a warming climate.Billings, L., 2018. From Earth to the Universe: Life, intelligence, and evolution. Biological Theory 13, 93-102. the scientific discourse on astrobiology—the study of the origin, evolution, and distribution of life in the universe—leans toward optimism about the possibility of extraterrestrial life, optimistic thinking is tempered by the limits of evidence and observations gathered thus far. Most astrobiologists assume that “first contact” with extraterrestrial life, if it is ever to occur, will likely be the discovery of microbial life elsewhere in our solar system. But in popular culture, “first contact” tends to be characterized as contact with extraterrestrial intelligence. This article will touch on theory and research relating to the origins and evolution of life and intelligence on Earth and speculation about extraterrestrial life and intelligence.Bin, J., Tian, F., Liu, L., 2018. New inner boundaries of the habitable zones around M dwarfs. Earth and Planetary Science Letters 492, 121-129. general circulation models CAM4 and CAM5 are used to study the climate of ocean planets around M dwarfs with different effective temperatures. The atmospheres in CAM5 simulations are warmer and contain more water vapor than those in CAM4 under identical model settings, a result likely caused by improved treatments of radiation and possibly clouds in CAM5. The inner boundary of the habitable zones of M dwarfs based on CAM5 simulations, expressed as a second order polynomial function, are farther away from the stars than what are suggested by previous works and the corresponding atmospheres are in the moist greenhouse state.Bl?ttler, C.L., Claire, M.W., Prave, A.R., Kirsim?e, K., Higgins, J.A., Medvedev, P.V., Romashkin, A.E., Rychanchik, D.V., Zerkle, A.L., Paiste, K., Kreitsmann, T., Millar, I.L., Hayles, J.A., Bao, H., Turchyn, A.V., Warke, M.R., Lepland, A., 2018. Two-billion-year-old evaporites capture Earth’s great oxidation. Science 360, 320-323.: Major changes in atmospheric and ocean chemistry occurred in the Paleoproterozoic era (2.5 to 1.6 billion years ago). Increasing oxidation dramatically changed Earth’s surface, but few quantitative constraints exist on this important transition. This study describes the sedimentology, mineralogy, and geochemistry of a 2-billion-year-old, ~800-meter-thick evaporite succession from the Onega Basin in Russian Karelia. The deposit consists of a basal unit dominated by halite (~100 meters) followed by units dominated by anhydrite-magnesite (~500 meters) and dolomite-magnesite (~200 meters). The evaporite minerals robustly constrain marine sulfate concentrations to at least 10 millimoles per kilogram of water, representing an oxidant reservoir equivalent to more than 20% of the modern ocean-atmosphere oxidizing capacity. These results show that substantial amounts of surface oxidant accumulated during this critical transition in Earth’s oxygenation.Editor's Summary: A strongly oxidizing Paleoproterozoic era. Two billion years ago, marine sulfate concentrations were around one-third as high as modern ones, constituting an oxidizing capacity equivalent to more than 20% of that of the modern ocean-atmosphere system. Bl?ttler et al. found this by analyzing a remarkable evaporite succession more than 1 billion years older than the oldest comparable deposit discovered to date. These quantitative results, for a time when only more qualitative information was previously available, provide a constraint on the magnitude and timing of early Earth's response to the Great Oxidation Event 2.3 billion years ago.Blockley, S., Candy, I., Matthews, I., Langdon, P., Langdon, C., Palmer, A., Lincoln, P., Abrook, A., Taylor, B., Conneller, C., Bayliss, A., MacLeod, A., Deeprose, L., Darvill, C., Kearney, R., Beavan, N., Staff, R., Bamforth, M., Taylor, M., Milner, N., 2018. The resilience of postglacial hunter-gatherers to abrupt climate change. Nature Ecology & Evolution 2, 810-818. the resilience of early societies to climate change is an essential part of exploring the environmental sensitivity of human populations. There is significant interest in the role of abrupt climate events as a driver of early Holocene human activity, but there are very few well-dated records directly compared with local climate archives. Here, we present evidence from the internationally important Mesolithic site of Star Carr showing occupation during the early Holocene, which is directly compared with a high-resolution palaeoclimate record from neighbouring lake beds. We show that—once established—there was intensive human activity at the site for several hundred years when the community was subject to multiple, severe, abrupt climate events that impacted air temperatures, the landscape and the ecosystem of the region. However, these results show that occupation and activity at the site persisted regardless of the environmental stresses experienced by this society. The Star Carr population displayed a high level of resilience to climate change, suggesting that postglacial populations were not necessarily held hostage to the flickering switch of climate change. Instead, we show that local, intrinsic changes in the wetland environment were more significant in determining human activity than the large-scale abrupt early Holocene climate events.Boethius, A., Ahlstr?m, T., 2018. Fish and resilience among Early Holocene foragers of southern Scandinavia: A fusion of stable isotopes and zooarchaeology through Bayesian mixing modelling. Journal of Archaeological Science 93, 196-210. study highlights the importance of different protein sources in the diet of Early and Middle Mesolithic humans in southern Scandinavia, and illustrates variation and change in protein consumption patterns during the Early Holocene. By combining previously published stable isotope data with new analyses of human and animal bone remains, a Bayesian mixing model was used to reveal that fishing was more important than previously anticipated in the foraging economy. Incorporating the zooarchaeological record as a prior to guide the Bayesian model enabled further study of Early Holocene foraging in the region. Although primarily a study of human diet, because the results indicate that aquatic systems were more important than previously acknowledged, it is possible to discuss the implications for understanding Early Holocene subsistence strategies and mobility. Furthermore, by incorporating both zooarchaeological data and human stable isotope analysis, the methodology can advance palaeodietary studies, by generating dietary protein estimations that can be used to investigate subsistence strategies across a diverse set of human societies.Boothroyd, I.M., Almond, S., Worrall, F., Davies, R.K., Davies, R.J., 2018. Assessing fugitive emissions of CH4 from high-pressure gas pipelines in the UK. Science of The Total Environment 631-632, 1638-1648. gas pipelines are an important source of fugitive methane emissions in lifecycle greenhouse gas assessments but limited monitoring has taken place of UK pipelines to quantify fugitive emissions. This study investigated methane emissions from the UK high-pressure pipeline system (National Transmission System - NTS) for natural gas pipelines. Mobile surveys of CH4 emissions were conducted across four areas in the UK, with routes bisecting high-pressure pipelines (with a maximum operating pressure of 85bar) and separate control routes away from the pipelines. A manual survey of soil gas measurements was also conducted along one of the high-pressure pipelines using a tunable diode laser. For the pipeline routes, there were 26 peaks above 2.1ppmv CH4 at 0.23peaks/km, compared with 12 peaks at 0.11peaks/km on control routes. Three distinct thermogenic emissions were identified on the basis of the isotopic signal from these elevated concentrations with a peak rate of 0.03 peaks/km. A further three thermogenic emissions on pipeline routes were associated with pipeline infrastructure. Methane fluxes from control routes were statistically significantly lower than the fluxes measured on pipeline routes, with an overall pipeline flux of 627 (241–1123 interquartile range) tonnes CH4/km/yr. Soil gas CH4 measurements indicated a total flux of 62.6 CH4 /yr, which equates to 2.9% of total annual CH4 emissions in the UK. We recommend further monitoring of the UK natural gas pipeline network, with assessments of transmission and distribution stations, and distribution pipelines necessary.Borrego, A.G., López García, A., Merino-Tomé, O., 2018. Petrographic and geochemical characterization of organic-rich Mississippian black shales in the north of Spain: Vegamián Formation, Cantabrian Zone. International Journal of Coal Geology 190, 126-145. shales (1–60m thick) with minor cherts (radiolarites) and phosphate nodules of Mississippian age (Middle–Upper Tournaisian; Vegamián Formation) occur in the fold-and-thrust belt of the Cantabrian Zone (N Spain) at the base of the Carboniferous succession, which is infilling the Variscan foreland basin. The Vegamián Formation was accumulated in a similar sedimentary and paleogeographic context to the Upper Devonian-Carboniferous black shales of the Appalachian, Arkoma, Fort Worth, Western Canada and Antler foreland basins (North America) and to the Variscan foreland basin in Belgium and Germany. Five stratigraphic sections were investigated in the southern branch of the Cantabrian Zone, corresponding to the shallower sectors of the passive margin of the Variscan foreland basin in N Spain, where this stratigraphic unit reaches a thickness of generally <15m. The Total Organic Carbon (TOC) ranges from 2.81wt% to 7.43wt% with a significant number of values over 5wt% indicating a high level of organic matter preservation. Thermal maturity can be considered to be between the peaks of oil and wet gas generation. The total sulphur (TS) content is generally low with few samples showing values higher than 1.5wt%. The organic matter is dominated by bitumen found either as diffuse masses, or concentrated in spaces and cavities, often parallel to the bedding planes or filling voids within calcite veins and fractures. Generally, the bitumen masses are homogeneous without secondary porosity, but occasionally they show mosaic optical texture indicating thermal transformation. Anastomosing structures, likely related to bituminite, are also common, and exhibit a large range of reflectances. Autochthonous organic matter (algae/bacteria) is seen as scarce Tasmanites and liptodetrinite, whereas allochthonous components (vitrinite, inertinite) are also scarce, except in the Olleros section. The range of reflectances of vitrinite-like particles is similar to that of bitumen but the identification is uncertain and therefore the reflectance of bitumen (BRr) has been used for thermal maturity assessment. A Gaussian-like distribution of bitumen reflectances was found for La Bra?a section (BRr=0.70%), whereas a bimodal distribution was observed in Olleros (BRr=0.70%) and Vegamián sections (BRr=0.95%) and large scatter of readings in Millaró (BRr~1.55%). The vitrinite reflectance equivalent estimated from aromatic compounds indicates that most of the existing correlations between vitrinite and bitumen reflectances underestimate the maturity of the lowest reflecting sections and overestimate it in the highest reflecting one. TS/TOC ratios, the geochemistry of organic matter and spectral gamma ray measurements suggest a normal marine to dysoxic environment of deposition with only local anoxia at the base of the Vegamián Formation.Bostick, K.W., Zimmerman, A.R., Wozniak, A.S., Mitra, S., Hatcher, P.G., 2018. Production and composition of pyrogenic dissolved organic matter from a logical series of laboratory-generated chars. Frontiers in Earth Science 6, 43. doi: 10.3389/feart.2018.00043. pyrogenic carbon (pyC) has been assumed to be predominantly stable, degradation and transfers of pyC between various pools have been found to influence its cycling and longevity in the environment. Dissolution via leaching may be the main control on loss processes such as microbial or abiotic oxidation, mineral sorption, or export to aquatic systems. Yet, little is known about the controls on pyrogenic dissolved organic matter (pyDOM) generation or composition. Here, the yield and composition of pyDOM generated through batch leaching of a thermal series of oak and grass biochars, as well as several non-pyrogenic reference materials, was compared to that of their parent solids. Over 17 daily leaching cycles, biochars made from oak at 250–650°C released decreasing amounts of C on both a weight (16.9–0.3%, respectively) and C yield basis (7.4–0.2% C, respectively). Aryl-C represented an estimated 32–82% of C in the parent solids (identified by 13C-NMR), but only 7–38% in the leachates (identified by 1H-NMR), though both increased with pyrolysis temperature. PyC, often operationally defined as condensed aromatic carbon (ConAC), was quantified using the benzenepolycarboxylic acid (BPCA) method. Tri- and tetra-carboxylated BPCAs were formed from non-pyrogenic reference materials, thus, only penta- and hexa-carboxylated BPCAs were used to derive a BPCA-C to ConAC conversion factor of 7.04. ConAC made up 24–57% of the pyrogenic solid C (excluding the 250°C biochar), but only about 9–23% of their respective leachates' DOC, though both proportions generally increased with pyrolysis temperature. Weighted BPCA compound distributions, or the BPCA Aromatic Condensation (BACon) Index, indicate that ConAC cluster size increased in pyrogenic solids but not in leachates. Additional evidence presented suggests that both aromatic cluster size and O-containing functional group contents in the pyrogenic solid control pyC solubility. Overall, pyDOM was found to be compositionally dissimilar from its parent chars and contained a complex mixture of organic compound groups. Thus, it is expected that estimates of dissolved pyC production and export, made only by detection of ConAC, are too low by factors of 4–11.Boyle, R.A., Dahl, T.W., Bjerrum, C.J., Canfield, D.E., 2018. Bioturbation and directionality in Earth's carbon isotope record across the Neoproterozoic–Cambrian transition. Geobiology 16, 252-278. of sediments by moving animals becomes apparent in the trace fossil record from about 550 million years ago (Ma), loosely overlapping with the tail end of the extreme carbonate carbon isotope δ13Ccarbonate fluctuations that qualitatively distinguish the Proterozoic geochemical record from that of the Phanerozoic. These Precambrian‐scale fluctuations in δ13Ccarbonate (PSF‐δ13Ccarbonate) remain enigmatic, due to their high amplitude and inclusion of global‐scale negative δ13Ccarbonate values, below anything attributable to mantle input. Here, we note that different biogeochemical‐model scenarios plausibly explaining globally synchronous PSF‐δ13Ccarbonate converge: via mechanistic requirements for extensive anoxia in marine sediments to support sedimentary build‐up of 13C‐depleted carbon. We hypothesize that bioturbation qualitatively reduced marine sediment anoxia by exposing sediments to oxygenated overlying waters, which ultimately contributed to decreasing the carbon cycle's subsequent susceptibility to PSF‐ δ13Ccarbonate. Bioturbation may also have reduced the quantity of (isotopically light) organic‐derived carbon available to contribute to PSF‐ δ13Ccarbonate via ocean crust carbonatization at depth. We conduct a comparative modelling exercise in which we introduce bioturbation to existing model scenarios for PSF‐ δ13Ccarbonate: expressing both the anoxic proportion of marine sediments, and the global organic carbon burial efficiency, as a decreasing function of bioturbation. We find that bioturbation's oxygenating impact on sediments has the capacity to prevent PSF‐ δ13Ccarbonate caused by authigenic carbonate precipitation or methanogenesis. Bioturbation's impact on the f‐ratio via remineralization is partially offset by liberation of organic phosphate, some of which feeds back into new production. We emphasize that this study is semiquantitative, exploratory and intended merely to provide a qualitative theoretical framework within which bioturbation's impact on long‐term, first‐order δ13Ccarbonate can be assessed (and it is hoped quantified in more detail by future work). With this proviso, we conclude that it is entirely plausible that bioturbation made a decisive contribution to the enigmatic directionality in the δ13Ccarbonate record, from the Neoproterozoic–Cambrian boundary onwards. Brakstad, O.G., St?rseth, T.R., Brunsvik, A., Bonaunet, K., Faksness, L.-G., 2018. Biodegradation of oil spill dispersant surfactants in cold seawater. Chemosphere 204, 290-293. biodegradation of chemically dispersed oil has been well documented, only a few studies have focused on the degradation of the dispersant compounds themselves. The objective of this study was to determine the biodegradation of dispersant surfactants in cold seawater, relevant for deep sea or Arctic conditions. Biotransformation of the surfactants dioctyl-sodium sulfosuccinate (DOSS), Tween 80, Tween 85, and α/β-ethylhexylsulfosuccinate (EHSS, expected DOSS hydrolysis product) in the commercial dispersants Corexit 9500, Dasic Slickgone NS and Finasol OSR52 were determined. The biotransformation studies of the surfactants were performed in natural seawater at 5?°C over a period of 54 days without oil present. The surfactants were tested at concentrations of 1, 5, and 50?mg/L, the lower concentration being as close as possible to expected field concentrations. Experiments with dispersants concentrations of 1?mg/L resulted in rapid biotransformation of Tween 80 and Tween 85, with depletion after 8 days, while DOSS showed rapid biotransformation after a lag period of 16 days. The degradation half-life of DOSS increased from 4.1 days to >500 days as Corexit 9500 concentrations went from 1?mg/L to 50?mg/L, emphasizing the importance of performing experiments at dispersant concentrations as close as possible to environmentally relevant concentrations. EHSS showed limited degradation compared to other surfactants. This study shows that the surfactants DOSS, Tween 80 and Tween 85 in the three chemical dispersants studied are biodegradable in cold seawater, particularly in environmentally relevant concentrations.Brakstad, O.G., St?rseth, T.R., R?nsberg, M.U., Hansen, B.H., 2018. Biodegradation-mediated alterations in acute toxicity of water-accommodated fraction and single crude oil components in cold seawater. Chemosphere 204, 87-91. biodegradation may be slower in cold Arctic than in temperate seawater, and this will affect the toxicity time window of the hydrocarbons. In this study, the acute toxicities of water-soluble phases of 1,3-dimethylnaphthalene, phenanthrene, fluoranthene, and low energy water-accommodated fractions (LE-WAFs) of an evaporated (200?°C+) crude oil, were screened by a Microtox bioassay during biodegradation in cold seawater (4–5?°C). The water-solubility of fluoranthene was too low to provoke a toxic response at any time, whereas the toxicity of 1,3-dimethylnaphthalene and phenanthrene decreased over time in relation to biotransformation of these compounds. In LE-WAFs, the Microtox EC50 was associated with biodegradation of the predominant hydrocarbons (naphthalenes, 2- to 3-ring PAH), as well as with phenol degradation products. The acute toxicities of single hydrocarbons and LE-WAFs persisted for a longer period in the cold seawater than previously shown at higher seawater temperatures. These results suggest implications for fate and effects assessment of hydrocarbons after oil spills in cold environments, like the Arctic. However, further biodegradation studies using Arctic seawater and relevant species for toxicity testing are needed for confirmation.Bravenec, A.D., Ward, K.D., Ward, T.J., 2018. Amino acid racemization and its relation to geochronology and archaeometry. Journal of Separation Science 41, 1489-1506. acid racemization, used as a method of relative and quantitative dating of fossils, evaluates the degree of postmortem conversion of l to d amino acid enantiomers. While extensively utilized, this method has garnered confusion due to controversial age estimates for human fossils in North America in the 1970s. This paper explains the age controversy and aftermath, current chromatographic methods used in research, mathematical calibration models, and a short synopsis of other dating techniques in geochronology and archaeometry.Bressanello, D., Liberto, E., Collino, M., Chiazza, F., Mastrocola, R., Reichenbach, S.E., Bicchi, C., Cordero, C., 2018. Combined untargeted and targeted fingerprinting by comprehensive two-dimensional gas chromatography: revealing fructose-induced changes in mice urinary metabolic signatures. Analytical and Bioanalytical Chemistry 410, 2723-2737. study exploits the information potential of comprehensive two-dimensional gas chromatography configured with a parallel dual secondary column-dual detection by mass spectrometry and flame ionization (GC×2GC-MS/FID) to study changes in urinary metabolic signatures of mice subjected to high-fructose diets. Samples are taken from mice fed with normal or fructose-enriched diets provided either in aqueous solution or in solid form and analyzed at three stages of the dietary intervention (1, 6, and 12?weeks). Automated Untargeted and Targeted fingerprinting for 2D data elaboration is adopted for the most inclusive data mining of GC×GC patterns. The UT fingerprinting strategy performs a fully automated peak-region features fingerprinting and combines results from pre-targeted compounds and unknowns across the sample-set. The most informative metabolites, with statistically relevant differences between sample groups, are obtained by unsupervised multivariate analysis (MVA) and cross-validated by multi-factor analysis (MFA) with external standard quantitation by GC-MS. Results indicate coherent clustering of mice urine signatures according to dietary manipulation. Notably, the metabolite fingerprints of mice fed with liquid fructose exhibited greater derangement in fructose, glucose, citric, pyruvic, malic, malonic, gluconic, cis-aconitic, succinic and 2-keto glutaric acids, glycine acyl derivatives (N-carboxy glycine, N-butyrylglycine, N-isovaleroylglycine, N-phenylacetylglycine), and hippuric acid. Untargeted fingerprinting indicates some analytes which were not a priori pre-targeted which provide additional insights: N-acetyl glucosamine, N-acetyl glutamine, malonyl glycine, methyl malonyl glycine, and glutaric acid. Visual features fingerprinting is used to track individual variations during experiments, thereby extending the panorama of possible data elaboration tools.Brewer, T.E., Fierer, N., 2018. Tales from the tomb: the microbial ecology of exposed rock surfaces. Environmental Microbiology 20, 958-970. a broad diversity of eukaryotic and bacterial taxa reside on rock surfaces where they can influence the weathering of rocks and minerals, these communities and their contributions to mineral weathering remain poorly resolved. To build a more comprehensive understanding of the diversity, ecology and potential functional attributes of microbial communities living on rock, we sampled 149 tombstones across three continents and analysed their bacterial and eukaryotic communities via marker gene and shotgun metagenomic sequencing. We found that geographic location and climate were important factors structuring the composition of these communities. Moreover, the tombstone‐associated microbial communities varied as a function of rock type, with granite and limestone tombstones from the same cemeteries harbouring taxonomically distinct microbial communities. The granite and limestone‐associated communities also had distinct functional attributes, with granite‐associated bacteria having more genes linked to acid tolerance and chemotaxis, while bacteria on limestone were more likely to be lichen associated and have genes involved in photosynthesis and radiation resistance. Together these results indicate that rock‐dwelling microbes exhibit adaptations to survive the stresses of the rock surface, differ based on location, climate and rock type, and seem pre‐disposed to different ecological strategies (symbiotic versus free‐living lifestyles) depending on the rock type.Brooks, A.S., Yellen, J.E., Potts, R., Behrensmeyer, A.K., Deino, A.L., Leslie, D.E., Ambrose, S.H., Ferguson, J.R., d’Errico, F., Zipkin, A.M., Whittaker, S., Post, J., Veatch, E.G., Foecke, K., Clark, J.B., 2018. Long-distance stone transport and pigment use in the earliest Middle Stone Age. Science 360, 90-94.. Previous research suggests that the complex symbolic, technological, and socioeconomic behaviors that typify Homo sapiens had roots in the middle Pleistocene <200,000 years ago, but data bearing on human behavioral origins are limited. We present a series of excavated Middle Stone Age sites from the Olorgesailie basin, southern Kenya, dating from ≥295,000 to ~320,000 years ago by argon-40/argon-39 and uranium-series methods. Hominins at these sites made prepared cores and points, exploited iron-rich rocks to obtain red pigment, and procured stone tool materials from ≥25- to 50-kilometer distances. Associated fauna suggests a broad resource strategy that included large and small prey. These practices imply notable changes in how individuals and groups related to the landscape and to one another and provide documentation relevant to human social and cognitive evolution.Editor's Summary: The Middle Stone Age in Africa. The Olorgesailie basin in the southern Kenya rift valley contains sediments dating back to 1.2 million years ago, preserving a long archaeological record of human activity and environmental conditions. Three papers present the oldest East African evidence of the Middle Stone Age (MSA) and elucidate the system of technology and behavior associated with the origin of Homo sapiens. Potts et al. present evidence for the demise of Acheulean technology that preceded the MSA and describe variations in late Acheulean hominin behavior that anticipate MSA characteristics. The transition to the MSA was accompanied by turnover of large mammals and large-scale landscape change. Brooks et al. establish that ～320,000 to 305,000 years ago, the populations in eastern Africa underwent a technological shift upon procurement of distantly sourced obsidian for toolmaking, indicating the early development of social exchange. Deino et al. provide the chronological underpinning for these discoveries.Browning, S.R., Browning, B.L., Zhou, Y., Tucci, S., Akey, J.M., 2018. Analysis of human sequence data reveals two pulses of archaic Denisovan admixture. Cell 173, 53-61.e9. modern humans interbred with Neanderthals and with a related archaic population known as Denisovans. Genomes of several Neanderthals and one Denisovan have been sequenced, and these reference genomes have been used to detect introgressed genetic material in present-day human genomes. Segments of introgression also can be detected without use of reference genomes, and doing so can be advantageous for finding introgressed segments that are less closely related to the sequenced archaic genomes. We apply a new reference-free method for detecting archaic introgression to 5,639 whole-genome sequences from Eurasia and Oceania. We find Denisovan ancestry in populations from East and South Asia and Papuans. Denisovan ancestry comprises two components with differing similarity to the sequenced Altai Denisovan individual. This indicates that at least two distinct instances of Denisovan admixture into modern humans occurred, involving Denisovan populations that had different levels of relatedness to the sequenced Altai Denisovan.Brownlee, D.E., Clark, B.C., A'Hearn, M.F., Sunshine, J.M., Nakamura, T., 2018. Flyby missions to comets and return sample analysis. Elements 14, 87-93. from flyby missions show comets to be geomorphically diverse bodies that spew jets of gas, dust, and rocks into space. Comet surfaces differ from other small bodies because of their ejection of mass into space. Comet solids &gt;2 μm are similar to primitive meteorite ingredients and include the highest temperature materials made in the early solar system. The presence of these materials in ice-rich comets is strong evidence for large-scale migration of solid grains in the early solar system. Cometary silicates appear to have formed in numerous hot solar system regions. Preserved interstellar grains are rare, unless they have eluded identification by having solar isotopic compositions.Brugger, J., Hofmann, M., Petri, S., Feulner, G., 2018. On the sensitivity of the Devonian climate to continental configuration, vegetation cover and insolation. Climate of the Past Discussions 2018, 1-27. the Devonian period (419 to 359 million years ago), life on Earth witnessed decisive evolutionary break-throughs, most prominently the colonisation of land by vascular plants and vertebrates. At the same time, it is also a period of major marine extinction events coinciding with marked changes in climate. There is limited knowledge about the causes of these changes and their interactions. It is therefore instructive to explore systematically how the Devonian climate system responds to changes in critical boundary conditions. Here we use coupled climate-model simulations to investigate separately the influence of changes in orbital parameters, continental configuration and vegetation cover on the Devonian climate. Variations of Earth's orbital parameters affect the Devonian climate system, with the warmest climate states at high obliquity and high eccentricity, but the amplitude of global temperature differences is smaller than suggested by an earlier study based on an uncoupled atmosphere model. The prevailing mode of climate variability on decadal to centennial timescales relates to surface air temperature fluctuations in high northern latitudes which are mediated by coupled oscillations involving sea-ice cover, ocean convection and a regional overturning circulation in the Arctic. Furthermore, we find only a small biogeophysical effect of changes in vegetation cover on global climate during the Devonian, and the impact of changes in continental configuration is small as well. Assuming decreasing atmospheric carbon dioxide concentrations throughout the Devonian, we then set up model runs representing the Early, Middle and Late Devonian. Comparing the simulations for these timeslices, the temperature evolution is dominated by the strong decrease in atmospheric carbon dioxide. In particular, the albedo change due to the in- crease in land vegetation alone cannot explain the temperature rise found in Late Devonian proxy data which remains difficult to reconcile with reconstructed falling carbon-dioxide levels. Simulated temperatures are significantly lower than estimates based on oxygen-isotope ratios, suggesting a lower δ18O ratio of Devonian seawater.Buck, K.N., Sedwick, P.N., Sohst, B., Carlson, C.A., 2018. Organic complexation of iron in the eastern tropical South Pacific: Results from US GEOTRACES Eastern Pacific Zonal Transect (GEOTRACES cruise GP16). Marine Chemistry 201, 229-241. iron, organic iron-binding ligands, and organic carbon were determined in full water column depth profiles across the US GEOTRACES Eastern Pacific Zonal Transect (GEOTRACES cruise GP16) in late 2013. Dissolved iron concentrations exhibited subsurface maxima associated with the remineralization of organic matter at the Peru shelf and with hydrothermal inputs from the East Pacific Rise. Iron-binding organic ligands are described as ligand classes based on defined ranges in conditional stability constants. The stronger L1-type ligands were measured in large excesses in surface and intermediate waters, and these excesses were negatively correlated with Si*, a biogeochemical proxy for iron limited diatom growth. These data suggest sources of strong iron-binding ligands from iron limitation of diatom communities, both locally and in waters originating from the Southern Ocean. Benthic sources of strong ligands were associated with new iron inputs from hydrothermal activity at the East Pacific Rise and from bottom sediments. In contrast to most studies in the Atlantic basin but consistent with previous datasets from the Pacific, stronger L1 ligands in this dataset were generally restricted to the upper water column and did not show large excesses through the water column. At depth, iron-binding ligands on GP16 were instead best described as L2 and L3 ligands. Concomitant decreases in excess L1, excess total ligands and dissolved organic carbon suggest similar degradation pathways of these pools below the surface.Byrne, J.M., Schmidt, M., Gauger, T., Bryce, C., Kappler, A., 2018. Imaging organic-mineral aggregates formed by Fe(II)-oxidizing bacteria using helium ion microscopy. Environmental Science & Technology Letters 5, 209–213. ion microscopy (HIM) has been used to image the development of mineralized twisted stalks produced by a neutrophilic, microaerophilic Fe(II)-oxidizing bacteria of the class Zetaproteobacteria. HIM is a relatively new type of microscopy which has several advantages over conventional scanning electron microscopy (SEM) due to its higher spatial resolution and the fact that samples can be imaged without coating (e.g. with Pt/Au). Here, we use HIM to show the development of nanometer- and micrometer-sized twisted stalk features consisting of organic material and Fe(III) minerals which appear to be loosely bound to the bacterial cells. These appendages are thought to be essential for eliminating Fe(III) waste produced during Fe(II) oxidation by sorbing Fe(III) and transporting it away from the cell. The results show the initial formation of long, precipitate free stalks. After just 2 days, these became encrusted with spikey lepidocrocite crystals, and by 1 month the characteristic twisted shape was almost indiscernible. These results demonstrate the high quality of images which can be obtained with Helium ion microscopy from organic and mineral structures produced by bacteria without the requirement to sputter coat samples with conductive metals and can thus be considered to be more representive of how these structures would exist in the environment.Cable, M.L., Vu, T.H., Maynard-Casely, H.E., Choukroun, M., Hodyss, R., 2018. The acetylene-ammonia co-crystal on Titan. ACS Earth and Space Chemistry 2, 366-375., the largest moon of Saturn, likely supports a rich organic mineralogy that we are only beginning to understand. Photochemistry in the upper atmosphere generates a complex array of organic molecules from the simple precursors N2 and CH4. These organics continue to react and combine, forming aerosol layers and ultimately depositing on the surface. Organics are transported via pluvial (rain) and fluvial (rivers/flooding) processes into the methane-based hydrocarbon lakes, where evaporation of volatile liquids can create evaporite deposits of remnant dissolved molecules. Within such deposits, chemical and physical processes may be occurring even at low temperatures. We have demonstrated in previous work that benzene and ethane rapidly form a unique and stable co-crystal at Titan surface temperatures (90–95 K), akin to a salt on Earth, where the weak van der Waals interactions in the benzene-ethane co-crystal are analogous to the ionic bonds in a salt. Here, we report the formation of a second co-crystal between acetylene and ammonia, which forms even more quickly and is stable through anticipated conditions of Titan “rain” events of liquid methane, ethane, and propane. Such co-crystals represent an exciting new class of possible minerals for Titan’s surface and may be responsible for processes such as selective sequestration and storage of species as well as having new properties for construction and erosive resistance of geological materials.Cadena, S., García-Maldonado, J.Q., López-Lozano, N.E., Cervantes, F.J., 2018. Methanogenic and sulfate-reducing activities in a hypersaline microbial mat and associated microbial diversity. Microbial Ecology 75, 930-940. and sulfate reduction are important microbial processes in hypersaline environments. However, key aspects determining substrate competition between these microbial processes have not been well documented. We evaluated competitive and non-competitive substrates for stimulation of both processes through microcosm experiments of hypersaline microbial mat samples from Guerrero Negro, Baja California Sur, Mexico, and we assessed the effect of these substrates on the microbial community composition. Methylotrophic methanogenesis evidenced by sequences belonging to methanogens of the family Methanosarcinaceae was found as the dominant methanogenic pathway in the studied hypersaline microbial mat. Nevertheless, our results showed that incubations supplemented with acetate and lactate, performed in absence of sulfate, also produced methane after 40?days of incubation, apparently driven by hydrogenotrophic methanogens affiliated to the family Methanomicrobiaceae. Sulfate reduction was mainly stimulated by addition of acetate and lactate; however, after 40?days of incubation, an increase of the H2S concentrations in microcosms amended with trimethylamine and methanol was also observed, suggesting that these substrates are putatively used for sulfate reduction. Moreover, 16S rRNA gene sequencing analysis showed remarkable differences in the microbial community composition among experimental treatments. In the analyzed sample amended with acetate, sulfate-reducing bacteria (SRB) belonging to the family Desulfobacteraceae were dominant, while members of Desulfohalobiaceae, Desulfomicrobiaceae, and Desulfovibrionaceae were found in the incubation with lactate. Additionally, we detected an unexpected high abundance of unclassified Hydrogenedentes (near 25%) in almost all the experimental treatments. This study contributes to better understand methanogenic and sulfate-reducing activities, which play an important role in the functioning of hypersaline environments.Caesar, L., Rahmstorf, S., Robinson, A., Feulner, G., Saba, V., 2018. Observed fingerprint of a weakening Atlantic Ocean overturning circulation. Nature 556, 191-196. Atlantic meridional overturning circulation (AMOC)—a system of ocean currents in the North Atlantic—has a major impact on climate, yet its evolution during the industrial era is poorly known owing to a lack of direct current measurements. Here we provide evidence for a weakening of the AMOC by about 3?±?1 sverdrups (around 15 per cent) since the mid-twentieth century. This weakening is revealed by a characteristic spatial and seasonal sea-surface temperature ‘fingerprint’—consisting of a pattern of cooling in the subpolar Atlantic Ocean and warming in the Gulf Stream region—and is?calibrated through an ensemble of model simulations from the CMIP5 project. We find this fingerprint both in a high-resolution climate model in response to increasing atmospheric carbon dioxide concentrations, and in the temperature trends observed since the late nineteenth century. The pattern can be explained by a slowdown in the AMOC and reduced northward heat transport, as well as an associated northward shift of the Gulf Stream. Comparisons with recent direct measurements from the RAPID project and several other studies provide a consistent depiction of record-low AMOC values in recent years.Caesar, L.K., Kvalheim, O.M., Cech, N.B., 2018. Hierarchical cluster analysis of technical replicates to identify interferents in untargeted mass spectrometry metabolomics. Analytica Chimica Acta 1021, 69-77. spectral data sets often contain experimental artefacts, and data filtering prior to statistical analysis is crucial to extract reliable information. This is particularly true in untargeted metabolomics analyses, where the analyte(s) of interest are not known a priori. It is often assumed that chemical interferents (i.e. solvent contaminants such as plasticizers) are consistent across samples, and can be removed by background subtraction from blank injections. On the contrary, it is shown here that chemical contaminants may vary in abundance across each injection, potentially leading to their misidentification as relevant sample components. With this metabolomics study, we demonstrate the effectiveness of hierarchical cluster analysis (HCA) of replicate injections (technical replicates) as a methodology to identify chemical interferents and reduce their contaminating contribution to metabolomics models. Pools of metabolites with varying complexity were prepared from the botanical Angelica keiskei Koidzumi and spiked with known metabolites. Each set of pools was analyzed in triplicate and at multiple concentrations using ultraperformance liquid chromatography coupled to mass spectrometry (UPLC-MS). Before filtering, HCA failed to cluster replicates in the data sets. To identify contaminant peaks, we developed a filtering process that evaluated the relative peak area variance of each variable within triplicate injections. These interferent peaks were found across all samples, but did not show consistent peak area from injection to injection, even when evaluating the same chemical sample. This filtering process identified 128 ions that appear to originate from the UPLC-MS system. Data sets collected for a high number of pools with comparatively simple chemical composition were highly influenced by these chemical interferents, as were samples that were analyzed at a low concentration. When chemical interferent masses were removed, technical replicates clustered in all data sets. This work highlights the importance of technical replication in mass spectrometry-based studies, and presents a new application of HCA as a tool for evaluating the effectiveness of data filtering prior to statistical analysis.Caetano-Filho, S., Paula-Santos, G.M., Dias-Brito, D., 2018. Carbonate REE?+?Y signatures from the restricted early marine phase of South Atlantic Ocean (late Aptian – Albian): The influence of early anoxic diagenesis on shale-normalized REE?+?Y patterns of ancient carbonate rocks. Palaeogeography, Palaeoclimatology, Palaeoecology 500, 69-83. earth elements plus yttrium have been extensively applied in paleoenvironmental studies of ancient carbonate successions due to their fractionation in the marine environment. However, in modern marine anoxic environments, seawater REE?+?Y signatures can be suppressed in reducing conditions (e.g. stagnant basins and/or early diagenesis) by REE remobilization from several sedimentary components (e.g. detrital siliciclastics, oxides, organic compounds). We present the shale-normalized REE?+?Y signatures for a transgressive marine carbonate succession of the primitive South Atlantic Ocean (latest Aptian-Albian), in a restricted marine setting with anoxic bottom conditions, to provide and evaluate the REE?+?Y record deposited in such conditions. Based on well-constrained paleoenvironmental reconstruction through microfacies analysis, three shale normalized REE?+?Y patterns were identified, varying according to the microfacies associations (MA) and related diagenetic environments: a) light REE-enriched patterns in the more proximal MA associated with burial diagenesis at the base of section; b) flat patterns towards distal MA related to anoxic and sulfidic early diagenesis; and c) middle REE-enriched patterns in MA related to dissolution of FeMn oxy-hydroxide grains under reducing early diagenesis. Cerium anomalies are absent due to stagnant water mass conditions, in accordance with previous studies for the early marine South Atlantic. Y/Ho ratios are lower than modern seawater values, with an increasing trend towards more distal facies. The “non-seawater” shale-normalized REE?+?Y patterns of the marine carbonates from the primitive South Atlantic Ocean corroborate studies in modern marine reducing environments, in which REE can be remobilized from detrital phases, oxides and organic compounds, suppressing the primary seawater REE?+?Y signature of authigenic minerals. Caution is suggested for the sole use of carbonate REE?+?Y signatures as paleoenvironmental proxies, especially in ancient successions lacking proper microfaciological components.Caforio, A., Siliakus, M.F., Exterkate, M., Jain, S., Jumde, V.R., Andringa, R.L.H., Kengen, S.W.M., Minnaard, A.J., Driessen, A.J.M., van der Oost, J., 2018. Converting Escherichia coli into an archaebacterium with a hybrid heterochiral membrane. Proceedings of the National Academy of Sciences 115, 3704-3709.: Escherichia coli has been engineered toward an archaebacterium with an unprecedented high level of archaeal ether phospholipids. The obtained cells stably maintain a mixed heterochiral membrane. This finding challenges theories that assume that intrinsic instability of mixed membranes led to the “lipid divide” and the subsequent differentiation of bacteria and archaea. Furthermore, this study paves the way for future membrane engineering of industrial production organisms with improved robustness.Abstract: One of the main differences between bacteria and archaea concerns their membrane composition. Whereas bacterial membranes are made up of glycerol-3-phosphate ester lipids, archaeal membranes are composed of glycerol-1-phosphate ether lipids. Here, we report the construction of a stable hybrid heterochiral membrane through lipid engineering of the bacterium Escherichia coli. By boosting isoprenoid biosynthesis and heterologous expression of archaeal ether lipid biosynthesis genes, we obtained a viable E. coli strain of which the membranes contain archaeal lipids with the expected stereochemistry. It has been found that the archaeal lipid biosynthesis enzymes are relatively promiscuous with respect to their glycerol phosphate backbone and that E. coli has the unexpected potential to generate glycerol-1-phosphate. The unprecedented level of 20–30% archaeal lipids in a bacterial cell has allowed for analyzing the effect on the mixed-membrane cell’s phenotype. Interestingly, growth rates are unchanged, whereas the robustness of cells with a hybrid heterochiral membrane appeared slightly increased. The implications of these findings for evolutionary scenarios are discussed.Cai, M., Duan, M., Guo, J., Liu, M., Qi, A., Lin, Y., Liang, J., 2018. PAHs in the Northern South China Sea: Horizontal transport and downward export on the continental shelf. Marine Chemistry 202, 121-129. investigate horizontal transport and particulate export of semivolatile pollutants on the continental shelf or marginal sea, surface and depth water samples were collected across the northern South China Sea (SCS) and analyzed for polycyclic aromatic hydrocarbons (PAHs). The total concentrations of Σ15PAH in seawater were in the range of 1.6–14?ng?L?1 (mean 5.5?ng?L?1), and the offshore decreasing trend of PAHs revealed intense terrigenous transport on the continental shelf, which was originated from combustion activity. Vertically, PAHs in the particulate phase followed surface-enrichment and depth-depletion pattern with a concentration maximum (2.9?ng?L?1) at the biomass maximum, while the dissolved PAH concentrations showed a minimum (1.5?ng?L?1) at the same depth. Particulate export fluxes of PAHs were between 24 and 195?ng?m?2?d?1 in the northern SCS based on 238U/234Th equilibria, which is suggested appropriate to quantify their downward flux in the upper water column. Efficient oceanic biological pump drives PAHs downward export to the deep ocean in the northern SCS.Callefo, F., Arduin, D.H., Ricardi-Branco, F., Galante, D., Rodrigues, F., Branco, F.C., 2018. The giant stromatolite field at Santa Rosa de Viterbo, Brazil (Paraná Basin) – A new paleoenvironmental overview and the consequences of the Irati Sea closure in the Permian. Journal of South American Earth Sciences 84, 299-314. city of Santa Rosa de Viterbo, S?o Paulo State, Brazil, contains an important geological and paleontological site that is part of the Paraná Basin and presents one of the most significant records of Permian microbial life of southwestern Gondwana: the giant stromatolite field, with structures reaching 3?m high and 6?m wide. This work proposes a new overview of the paleoenvironment, focusing on the growth and development of microbial mats and microbialites. The characterization and association of nine facies were performed: intraformational breccia with wackestone matrix, intraformational breccia with grainstone matrix, packstone, wackestone, microbial mats, peloidal wackestone, laminated peloidal wackestone, laminated peloidal packstone and stromatolites. Four lithologic logs were correlated and used to interpret the history of the establishment of microbial communities during the episode of the Irati Sea closure. Field studies were carried out, thin sections were analyzed, and techniques such as SEM/EDS and Raman spectroscopy were applied for compositional analysis and to aid in the identification of associated fossils. This moment in the Paraná Basin's evolution was important due to the noteworthy increase in rates of organic matter deposition and the significant proliferation of microbial life brought about by the closure of the Irati Sea. One hypothesis is that there was more than one attempt to establish microbial communities during the paleoenvironmental evolution, and success was achieved only after a decrease in water depth and energy of the depositional system, as well as after an increase in salinity. As a result of a reconfiguration of paleogeography in the Gondwana supercontinent, the closure of the Irati Sea significantly affected the development and establishment of microbial communities, which gave rise to extensive microbialitic structures such as those at Santa Rosa de Viterbo.Canfield, D.E., Zhang, S., Wang, H., Wang, X., Zhao, W., Su, J., Bjerrum, C.J., Haxen, E.R., Hammarlund, E.U., 2018. A Mesoproterozoic iron formation. Proceedings of the National Academy of Sciences 115, E3895-E3904.: Iron formations (IFs) are common before 1,800 million years ago (Ma) and again at ～750 Ma, but are remarkably absent for the billion years in between. We report on a 1,400-Ma IF of ～520 gigatons Fe from the Xiamaling Formation on the North China Craton. Biomarker analyses suggest that anoxygenic phototrophic bacteria were involved in Fe(II) oxidation, and further geochemical analysis shows that IF sediments supported active microbial Fe reduction that rivaled oxic respiration in its efficiency of organic matter oxidation. The Xiamaling Formation IF demonstrates that geochemical conditions occasionally conspired to produce world-class IFs during Earth’s “middle ages,” permitting critical insights into the biogeochemical processes of IF emplacement.Abstract: We describe a 1,400 million-year old (Ma) iron formation (IF) from the Xiamaling Formation of the North China Craton. We estimate this IF to have contained at least 520 gigatons of authigenic Fe, comparable in size to many IFs of the Paleoproterozoic Era (2,500–1,600 Ma). Therefore, substantial IFs formed in the time window between 1,800 and 800 Ma, where they are generally believed to have been absent. The Xiamaling IF is of exceptionally low thermal maturity, allowing the preservation of organic biomarkers and an unprecedented view of iron-cycle dynamics during IF emplacement. We identify tetramethyl aryl isoprenoid (TMAI) biomarkers linked to anoxygenic photosynthetic bacteria and thus phototrophic Fe oxidation. Although we cannot rule out other pathways of Fe oxidation, iron and organic matter likely deposited to the sediment in a ratio similar to that expected for anoxygenic photosynthesis. Fe reduction was likely a dominant and efficient pathway of organic matter mineralization, as indicated by organic matter maturation by Rock Eval pyrolysis combined with carbon isotope analyses: Indeed, Fe reduction was seemingly as efficient as oxic respiration. Overall, this Mesoproterozoic-aged IF shows many similarities to Archean-aged (>2,500 Ma) banded IFs (BIFs), but with an exceptional state of preservation, allowing an unprecedented exploration of Fe-cycle dynamics in IF deposition.Cardott, B.J., Curtis, M.E., 2018. Identification and nanoporosity of macerals in coal by scanning electron microscopy. International Journal of Coal Geology 190, 205-217. applications of scanning electron microscopy (SEM) to shale resource plays at magnifications of <500–>80,000× have reported nanoporosity in organic matter with limited interpretations of organic matter type. Macerals, inclusive of kerogen and solid bitumen, are recognized and distinguished in reflected white and epifluorescent light in coal and shale samples at magnifications of 200–750×. The objectives of this study are to identify macerals by SEM and evaluate which macerals contain primary and secondary nanoporosity. Since coals are organic rich with a better chance of identifying adjacent maceral types than when dispersed in shales, broad ion beam milled samples of humic and sapropelic (boghead and cannel) coals ranging in rank from peat to semianthracite were examined in backscattered electron (BSE) mode at low magnification (≤2,500×) to identify maceral type. Once identified, macerals were examined at higher magnifications of 1200–75,000× to assess maceral nanoporosity. Manipulation of the accelerating voltage to 10kV in BSE mode of a high volatile bituminous humic coal durain lithotype sample revealed a contrast between maceral groups (vitrinite, inertinite, liptinite), with limited identification of individual maceral types. Vitrinite maceral subgroups telovitrinite and detrovitrinite are distinguished based on their relative gray scale appearance compared to other macerals and occurrence as bands or groundmass, respectively. The liptinite macerals alginite, sporinite and cutinite are distinguished based on dark relative gray level and their shape. The liptinite maceral bituminite/amorphinite was recognized by dark relative gray level and occurrence as groundmass in a boghead coal. The inertinite macerals fusinite and semifusinite are recognized by light gray level appearance compared to other macerals and bogen structure but are not distinguishable separately. Macerals dispersed in shale, lacking the subtle contrast of adjacent macerals, are much more difficult to identify. Even though porosity is revealed at high magnification in BSE mode, too high of a magnification (>15,000×) prohibits identification of maceral types. The best approach is to examine samples at a lower magnification (e.g., 650×) at 10kV accelerating voltage in BSE mode to identify the maceral type and then go to a higher magnification at 1–2kV accelerating voltage to observe nanoporosity. Primary nanoporosity is observed within coal macerals at low rank (peat and subbituminous), but decreases in amount with increasing rank. Primary microporosity occurs as woody cell lumens in semifusinite and fusinite macerals. Secondary nanoporosity develops in post-oil solid bitumen in shale beginning below the peak of the oil window with a lack of nanoporosity at lower thermal maturity. Compared to the abundant nanoporosity of post-oil solid bitumen in shale, only trace amounts of nanoporosity is observed in other macerals in coals of high volatile bituminous rank and higher under the SEM. The emphasis of this study was the identification and nanoporosity of macerals in coal by SEM. The same results may extend to the same macerals in shale. Knowledge of organic matter porosity distribution by maceral type and development by thermal maturity provides insight for coalbed methane, shale gas and tight oil production potential.Carvajal-Ortiz, H., Gentzis, T., 2018. Geochemical screening of source rocks and reservoirs: The importance of using the proper analytical program. International Journal of Coal Geology 190, 56-69. screening is routinely integrated into larger exploration (and sometimes development) programs that also include assessments of the geological setting, petrophysics, mechanical properties of the rock, etc. The Rock-Eval analytical equipment and its classical Basic/Bulk-Rock method have been developed mainly to characterize potential source-rock intervals in petroleum systems. However, with the increasing interest in unconventional plays, it has been recently demonstrated that the use of modified pyrolysis-temperature regimes improves the quantification of hydrocarbons still present in oil-impregnated samples. In spite of their availability, the use of such modified pyrolysis-temperature regimes still remains scarce among users of pyrolysis data (e.g., exploration geologists and geochemists, reservoir engineers, petrophysicists, and other geoscientists). Several cases were selected to portray how different analytical programs are necessary to obtain less biased and more accurate answers to critical questions during prospect and play evaluations and appraisals. Samples originating from conventional and unconventional plays in the Greater Permian Basin of West Texas (Wolfcamp & Spraberry formations), the DJ Basin in Colorado (Niobrara Formation), the Williston Basin (Lower Bakken Shale), and source-rock reservoirs in the Middle East were analysed each using three known different pyrolysis methods, namely the Institut Fran?ais du Pétrole's “Basic/Bulk-Rock”, “Reservoir”, and “Shale Play”. The Shale Play and Reservoir pyrolysis methods yield oil-in-place estimates 20–42% higher than those yielded by the Basic/Bulk-Rock method on the same sample (e.g., for the Niobrara Formation – 87bbl oil/ac-ft Bulk method, 118bbl oil/ac-ft Reservoir method, 119bbl/ac-ft Shale method; for the Lower Bakken – 194bbl oil/ac-ft Bulk method, 246bbl oil/ac-ft Shale method). In addition, a mature, source-rock interval believed to contain gas-prone organic matter (Type III) based solely on TOC and pyrolysis data, was re-interpreted as composed mainly of amorphous oil-prone kerogen, following a multi-component study (which included transmitted and reflected-light organic petrography). These results present unequivocal evidence that underestimating the importance of selecting the proper analytical program can change interpretations dramatically.Cecotti, M., Coppotelli, B.M., Mora, V.C., Viera, M., Morelli, I.S., 2018. Efficiency of surfactant-enhanced bioremediation of aged polycyclic aromatic hydrocarbon-contaminated soil: Link with bioavailability and the dynamics of the bacterial community. Science of The Total Environment 634, 224-234. in the bacterial-community dynamics, bioavailability, and biodegradation of polycyclic aromatic hydrocarbons (PAHs) of chronically contaminated soil were analyzed in Triton X-100–treated microcosms at the critical micelle concentration (T-CMC) and at two sub-CMC doses. Only the sub-CMC-dose microcosms reached sorbed-PAH concentrations significantly lower than the control: 166 ± 32 and 135 ± 4 mg kg?1 dry soil versus 266 ± 51 mg kg?1; consequently an increase in high- and low-molecular-weight PAHs biodegradation was observed. After 63 days of incubation pyrosequencing data evidenced differences in diversity and composition between the surfactant-modified microcosms and the control, with those with sub-CMC doses containing a predominance of the orders Sphingomonadales, Acidobacteriales, and Gemmatimonadales (groups of known PAHs-degrading capability). The T-CMC microcosm exhibited a lower richness and diversity index with a marked predominance of the order Xanthomonadales, mainly represented by the Stenotrophomonas genus, a PAHs- and Triton X-100–degrading bacterium. In the T-CMC microcosm, whereas the initial surface tension was 35 mN m?1, after 63 days of incubation an increase up to 40 mN m?1 was registered. The previous observation and the gas-chromatography data indicated that the surfactant may have been degraded at the CMC by a highly selective bacterial community with a consequent negative impact on PAHs biodegradation. This work obtained strong evidence for the involvement of physicochemical and biologic influences determining the different behaviors of the studied microcosms. The results reported here contribute significantly to an optimization of, surfactant-enhanced bioremediation strategies for chronically contaminated soil since the application of doses below the CMC would reduce the overall costs.Chakraborty, N., Sarkar, S., Mandal, A., Mandal, S., Bumby, A., 2018. Microenvironmental constraint on δ13C depletion: Garudamangalam Sandstone, Cauvery Basin, India. Marine and Petroleum Geology 91, 776-784. the hydrocarbon-producing Cretaceous marine Uttatur Group, Cauvery Basin, India, the Garudamangalam Sandstone Formation is at top of a TST-HST transit. The δ13C value is expectedly depleted within the calcareous Garudamangalam Sandstone, which is the top most unit of the Uttatur Group, overlying the Karai Shale. The calcareous sandstone was deposited in a coastal setting around a shore-parallel river mouth bar. Instances of excessive depletion of δ13C up to ?44.5‰ in the carbonate cement is suggestive of methane generation and its subsequent sequestration. The common occurrence of early diagenetic pyrite in these rocks testifies to the proliferation of sulfate-reducing bacteria and is suggestive of methane generation beneath the sulfate reduction zone. Upward-moving diffusive methane was possibly consumed by methanotrophs at the base of the sulfate-reduction zone. Abundant fabric-selective carbonate cement corroborates microbially-controlled anaerobic oxidation of methane. The presumed high rate of nutrient supply, abundance of vegetative material and moderately high organic carbon content in sediments (av. 1.6%), support this contention. All the samples which have the greatest δ13C depletion are characterized by enriched organic carbon and are derived from a tidal inlet-mouth facies, and selectively from mud drapes on cross-bedding in tidal strata. Calcarenite at the base of the same cross-strata are invariably much less depleted in δC13. This range of relationships indicates the transport of methanotrophs that settled on foreset beds mostly as tides slackened under the broader control of neap-spring cycles.Chandrasekhar, S., Sharma, H., Mohanty, K.K., 2018. Dependence of wettability on brine composition in high temperature carbonate rocks. Fuel 225, 573-587. experiments and small-scale field tests have shown that injection of low salinity brine can improve oil recovery from carbonate rocks. Contact angle studies, spontaneous imbibition and core flood experiments indicate that wettability alteration is responsible for this process. In this study, the core-scale manifestation of wettability mechanisms is evaluated, and a geochemical model is developed for further insight into reaction pathways. Brines of different compositions were injected into carbonate cores with no oil and the effluent was analyzed for ionic composition. Seawater, sulfate-rich seawater, and dilutions of seawater were tested. A mechanistic model was developed using our in-house reservoir simulator UTCHEM-IPHREEQC for the wettability alteration process. The model changes core wettability according to the adsorbed naphthenic acid concentration on the rock surface, which is controlled by the brine composition. The model was used to match previously published two-phase flow experiments. The single-phase core floods with test brines indicate retention of SO42? within the core. Calcite dissolution is prominent in ultra-dilute seawater injection. The relative permeability parameters for oil-wet and water-wet conditions were different, but the same for all the core floods. Model results were in good agreement with single-phase core floods and oil recovery experiments. Sulfate adsorption and calcium dissolution led to naphthenic acid desorption which in turn altered core wettability. Single-phase core floods reached equilibrium within 2 pore volumes (PV) of injection. Two-phase core floods with seawater and sulfate enriched seawater took longer to reach equilibrium, only after 3–4 PV. Oil-displacing ultra-dilute brine injection experiments did not reach equilibrium in 5 PV, particularly the Ca2+ ions, due to slow calcite dissolution.Chang, X., Wang, Y., Xu, Y., Cui, J., Wang, T., 2018. On the changes of polycyclic aromatic compounds in waterflooded oil and their implications for geochemical interpretation. Organic Geochemistry 120, 56-74. oilfield had been producing for over twenty years and became waterflooded ten years ago. Samples from nine producing wells drilled recently in the Qudi oilfield were collected during the three recovery stages spanning an eight month interval of waterflooding and were analyzed for changes in their polycyclic aromatic compounds (PACs). The results indicate that most of waterflooded oils are characterized by increased tricyclic, tetracyclic, pentacyclic and triaromatic steroids concentrations. The irregular changes in parameters based on two or fewer alkyl-substituted naphthalenes (MNR, ENR, DBR, DNR-1) implies a different depletion order for the PACs because the abundances of the compounds are controlled by the predominance of water washing and biodegradation over a certain time. The increase in DBTs and DBFs with water washing reflects their strong resistance to biodegradation. Lower aqueous solubility and strong resistance to biodegradation are possibly responsible for the mainly unchanged values of the three or more alkylnaphthalene-related parameters (TNR-1, TDE-1, TDE-3, TBR and TeBR), tricyclic aromatics (MPI-1 and PP-1), tetracyclic aromatics (MCI, MCI2, 2-MC/1-MC, and BaA/(BaA?+?Chry)), triaromatic steroids parameters (C26-TAS/C28-TAS, C27-TAS/C28-TAS, C28-TAS 20S/(20R?+?20S), and TA(I)/TA(I?+?II)), and heterocyclic aromatic parameters (4-MDBT/DBT, 4-MDBT/1-MDBT, and 4,6-DMDBT/(1,4?+?1,6)-DMDBT), confirming their validity for geochemical interpretation even after extensive water washing. However, pentacyclic aromatic parameters (BeP/Pe, (BeP?+?BaP)/Pe, BF/Pe, and BF/BeP), which are theoretically expected to be unaffected, change significantly with the advance of the waterflooding process, implying a complex alteration mechanism that needs further investigation.Charbonnier, Q., Moynier, F., Bouchez, J., 2018. Barium isotope cosmochemistry and geochemistry. Science Bulletin 63, 385-394. the isotopic variations of barium were reported for the first time fourty years ago, the number of studies on barium isotopes significantly increased only after 2010. Barium isotope anomalies in meteorites have been successfully used to provide constraints about the origin of presolar SiC grains. In carbonaceous chondrites Ba isotope anomalies are indicative of the heterogeneity of the early solar system, possibly resulting from of a later injection of material after the cooling of solar system. Barium isotope fractionation in the same carbonaceous chondrites suggests that a strong magnetic field was present in the innermost part of the early solar system. Barium mass-dependent isotope fractionation has also been detected throughout Earth surface materials. While igneous rocks show limited Ba isotopic variations, relatively large isotopic variations are observed amongst and within soils, rivers, and biological materials. Indeed, plants seem to fractionate Ba isotopes during Ba uptake from soil solutions. Therefore, Ba isotope signatures have the potential to provide clues on the biological cycling of Ba at the Earth surface. In seawater, Ba isotopic variations have been mapped out, and are mainly related to barite precipitation, which is in turn related to organic matter remineralization in the water column. This makes Ba isotopes a potentially powerful tool to reconstruct past ocean productivity, although constraints are still lacking regarding the inputs of dissolved Ba to the oceans by rivers or hydrothermalism.Chen, G., Lu, S., Liu, K., Han, T., Xu, C., Xue, Q., Shen, B., Guo, Z., 2018. GCMC simulations on the adsorption mechanisms of CH4 and CO2 in K-illite and their implications for shale gas exploration and development. Fuel 224, 521-528. the adsorption mechanism of shale gas is an essential pre-requisite for establishing models to evaluate the adsorbed gas amount under geological conditions quantitatively and to guide shale gas exploration and development. By using the Grand Canonical Monte Carlo (GCMC) method, we simulated the adsorption behavior of CH4 and CO2 in K-illite slit pores, and revealed the key gas adsorption mechanisms and discussed their implications on shale gas exploration and development by analyzing the distribution of gas mole concentration, gas-surface interaction energy, density field and etc. It is found that even with the presence of weak adsorption layers in meso and macro pores, the adsorption behavior of both CH4 and CO2 is dominated by the strong adsorption layers and thus can only be approximated but not strictly described by the classic Langmuir model. However, the micro-pore filling effect leads to the overlap of adsorption layers in micro pores, causing more deviation when using the classic Langmuir model to evaluate the adsorption behavior. Even though the adsorption behavior is not affected by pore size dimensions in meso and macro pores, the proportion of the adsorbed gas increases with the decreasing pore size. Both CH4 and CO2 are adsorbed in the center of the six-membered oxygen ring on the silicon oxygen tetrahedron surface. The CH4 molecules (with no polarity) are at the center of the ring, but the CO2 molecules (with electric quadrupole moment) are closer to the oxygen atom with polarity in the ring. The electric quadrupole moment makes the adsorption capacity of CO2 much stronger than that of CH4 in K-illite pores, providing a theoretical basis for enhancing CH4 recovery efficiency by injecting CO2 in the development of shale gas.Chen, G., Lu, S., Zhang, J., Pervukhina, M., Liu, K., Wang, M., Han, T., Tian, S., Li, J., Zhang, Y., Xu, C., 2018. A method for determining oil-bearing pore size distribution in shales: A case study from the Damintun Sag, China. Journal of Petroleum Science and Engineering 166, 673-678. good understanding of oil-bearing pore size distribution (PSD) in shales is crucial for determining reservoir sweet-spots. In this paper, we determined the oil-bearing PSD in lacustrine shales at peak oil generation by comparing PSDs between the extracted and un-extracted shale samples, and by relating the difference in PSDs between the extracted and un-extracted shale samples to the oil content in shales. It is found that while the specific pore volume (SPV) of meso pores are nearly 8 times as large as that of micro pores, macro pores contribute to the majority of the pore volume in lacustrine shales at peak oil generation. SPVs of the extracted samples are generally larger than that of the un-extracted ones. The oil-bearing PSD in pores with sizes up to 80?nm were obtained by subtracting SPVs of the un-extracted samples from that of the extracted ones within specific pore size intervals. The oil-bearing mechanism was further investigated by linking the oil-bearing PSD to the total oil content obtained from pyrolysis experiments. It is found that the content of oil residing in the micro and meso pores is significantly less than the total oil content, indicating that the oil is mainly contained in the macro pores. Therefore, the abundance and distribution of macro pores in lacustrine shales at peak oil generation are critical factors of a shale oil reservoir.Chen, H., Yang, Z., Chu, R.K., Tolic, N., Liang, L., Graham, D.E., Wullschleger, S.D., Gu, B., 2018. Molecular insights into Arctic soil organic matter degradation under warming. Environmental Science & Technology 52, 4555-4564. composition of the Arctic soil organic carbon (SOC) and its susceptibility to microbial degradation are uncertain due to heterogeneity and unknown SOC compositions. Using ultrahigh-resolution mass spectrometry, we determined the susceptibility and compositional changes of extractable dissolved organic matter (EDOM) in an anoxic warming incubation experiment (up to 122 days) with a tundra soil from Alaska (United States). EDOM was extracted with 10 mM NH4HCO3 from both the organic- and mineral-layer soils during incubation at both ?2 and 8 °C. Based on their O:C and H:C ratios, EDOM molecular formulas were qualitatively grouped into nine biochemical classes of compounds, among which lignin-like compounds dominated both the organic and the mineral soils and were the most stable, whereas amino sugars, peptides, and carbohydrate-like compounds were the most biologically labile. These results corresponded with shifts in EDOM elemental composition in which the ratios of O:C and N:C decreased, while the average C content in EDOM, molecular mass, and aromaticity increased after 122 days of incubation. This research demonstrates that certain EDOM components, such as amino sugars, peptides, and carbohydrate-like compounds, are disproportionately more susceptible to microbial degradation than others in the soil, and these results should be considered in SOC degradation models to improve predictions of Arctic climate feedbacks.Chen, J., Monta?ez, I.P., Qi, Y., Shen, S., Wang, X., 2018. Strontium and carbon isotopic evidence for decoupling of pCO2 from continental weathering at the apex of the late Paleozoic glaciation. Geology 46, 395-398.’s penultimate icehouse (ca. 340–285 Ma) was a time of low atmospheric pCO2 and high pO2, formation of the supercontinent Pangaea, dynamic glaciation in the Southern Hemisphere, and radiation of the oldest tropical rainforests. Although it has been long appreciated that these major tectonic, climatic, and biotic events left their signature on seawater 87Sr/86Sr through their influence on Sr fluxes to the ocean, the temporal resolution and precision of the late Paleozoic seawater 87Sr/86Sr record remain relatively low. Here we present a high-temporal-resolution and high-fidelity record of Carboniferous–early Permian seawater 87Sr/86Sr based on conodont bioapatite from an open-water carbonate slope succession in south China. The new data define a rate of long-term rise in 87Sr/86Sr (0.000035/m.y.) from ca. 334–318 Ma comparable to that of the middle to late Cenozoic. The onset of the rapid decline in 87Sr/86Sr (0.000043/m.y.), following a prolonged plateau (318–303 Ma), is constrained to ca. 303 Ma. A major decoupling of 87Sr/86Sr and pCO2 during 303–297 Ma, coincident with the Paleozoic peak in pO2, widespread low-latitude aridification, and demise of the pan-tropical wetland forests, suggests a major shift in the dominant influence on pCO2 from continental weathering and organic carbon sequestration (as coals) on land to organic carbon burial in the ocean.Chen, L., Feng, Y., Okajima, J., Komiya, A., Maruyama, S., 2018. Production behavior and numerical analysis for 2017 methane hydrate extraction test of Shenhu, South China Sea. Journal of Natural Gas Science and Engineering 53, 55-66. one promising energy resource, methane hydrate (MH) has extracted worldwide attention in recent years. In 2017, a new series of methane hydrate (MH) extraction tests was executed both in China (Shenhu Area, South China Sea) and Japan (Nankai Trough), which led to new round of intense scientific research and engineering developments toward the common goal of robust production technology. This study is focused on the production behavior analysis and numerical predictions for 2017 tests in Shenhu Area, South China Sea. Based on the open production data, the detailed production process, characteristics and future prospects are re-constructed and numerically discussed, so as to provide a general view of the production behaviors and potential prediction in this region. Numerical simulations on the mid-term (60 days) production process are designed and found good agreement with the real production tests, where the short-to mid-term production rate is estimated to drop from 3.5?×?104?m3/d to around 2.0?×?103?m3/d within 60 days, which is then extended for mid-to long-term (2–3 years) prediction of gas production. Parameter behaviors and field information such as the near-wellbore effects are also discussed into detail based on the numerical results. In addition, future concerns based on recent tests in China and Japan in 2017 are also included in this study, so as to provide a general viewpoint for oceanic methane hydrate extraction.Chen, Q., Deng, Y., Wei, J., Ma, G., Long, L., Xiao, W., Li, W., Zhang, L., 2018. Types, distribution and play targets of Lower Cretaceous tight oil in Jiuquan Basin, NW China. Petroleum Exploration and Development 45, 227-238. on drilling and laboratory data, the formation conditions of tight oil reservoirs in the Jiuquan basin were comprehensively analyzed and the exploration domains were sorted out. The Jiuquan basin underwent three cycles of lake level fluctuation in early Cretaceous, leaving three sets of high-quality source rocks, the Zhonggou, Xiagou and Chijinbao Formations in the Lower Cretaceous. There are two types of reservoir assemblages, source-reservoir in one type and source below reservoir type, and two types of tight reservoirs, argillaceous dolomite and conglomerate. The “sweet spots” control the enrichment of oil and gas. Argillaceous dolomite tight oil reservoirs have the characteristic of “integrated source-reservoir”, with fractures connecting the matrix micro-pores, pore-fracture type and fracture-pore type “sweet spots” distributed in large scale. The sandy conglomerate tight oil reservoirs were formed by source-reservoir lateral connection, and can be divided into source below reservoir type, source-reservoir side by side type and “sandwich” type. The overlapping areas of the favorable facies belts of fan-delta front and the secondary pore developing belts are the “sweet spot” sites. The favorable areas for seeking conglomerate tight oil are fan-delta front deposits around the Qingxi, Ying'er and Huahai sags, with an exploration area of 550 km2; while the area to seek argillaceous dolomite tight oil is the NW fracture developed belt in Qingxi sag, with an exploration area of 100 km2.Chen, S., Sun, S., Xu, Y., Lv, J., Chen, L., Liu, L., 2018. Halorubrum depositum sp. nov., a novel halophilic archaeon isolated from a salt deposit. Current Microbiology 75, 677-683. non-motile, pleomorphic rod-shaped or oval, red-pigmented (nearly scarlet), extremely halophilic archaeon, strain Y78T, was isolated from a salt deposit of Yunnan salt mine, China. Analysis of the 16S rRNA gene sequence showed that it was phylogenetically related to species of the genus Halorubrum, with a close relationship to Halorubrum rutilum YJ-18-S1T (98.6%), Halorubrum yunnanense Q85T (98.3%), and Halorubrum lipolyticum 9-3T (98.1%). The temperature, NaCl, and pH ranges for growth were 25–50 °C, 12–30% (w/v), and 6.5–9.0, respectively. Mg2+ was required for growth. The polar lipids of strain Y78T were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, and a sulfated diglycosyl diether. The DNA G+C content was 66.6 mol%. DNA–DNA hybridization values between strain Y78T and two closely related species of the genus Halorubrum were far below 70%. Based on the data presented in this study, strain Y78T represents a novel species for which the name Halorubrum depositum sp. nov. is proposed; the type strain is Y78T (=?CGMCC 1.15456T?=?JCM 31272T). The GenBank/EMBL/DDBJ accession numbers of the 16S rRNA, rpoB′ and ef-2 sequences of strain Y78T are KX376712, KX530069, and KX530068, respectively. The protologue has been submitted to the Digital Protologue database (<;) under the Taxon Number TA00336.Chen, S., Wang, F., Zhang, Y., Qin, S., Wei, S., Wang, S., Hu, C., Liu, B., 2018. Organic carbon availability limiting microbial denitrification in the deep vadose zone. Environmental Microbiology 20, 980-992. in the deep vadose zone play an essential role in the mitigation of nitrate leaching; however, limited information is available on the mechanisms of microbial denitrification due to sampling difficulties. We experimentally studied the factors that affect denitrification in soils collected down to 10.5 meters deep along the soil profile. After an anoxic pre‐incubation, denitrification rates moderately increased and the N2O/(N2O?+?N2) ratios declined while the microbial abundance and diversity did not change significantly in most of the layers. Denitrification rate?was significantly enhanced and the abundance of the denitrification genes was simultaneously elevated by the increased availability of organic carbon in all studied layers, to a greater extent in the subsurface layers than in the surface layers, suggesting the severe scarcity of carbon in the deep vadose zone. The genera Pseudomonas and Bacillus, which are made up of a number of species that have been previously identified as denitrifiers in soil, were the major taxa that respond to carbon addition. Overall, our results suggested that the limited denitrification in the deep vadose zone is not because of the lack of denitrifiers, but due to the low abundance of denitrifiers which is caused by low carbon availability.Chen, X., Xu, C., Zhang, W., Ma, C., Liu, X., Zhao, S., Shi, Q., 2018. Separation and molecular characterization of ketones in a low-temperature coal tar. Energy & Fuels 32, 4662-4670. are major oxygen-containing compounds in low-temperature coal tars (LTCTs); however, the molecular composition of these compounds is not well characterized as a result of the complexity of itself and the interference of the coal tar matrix. In this study, ketones were separated from a LTCT and characterized by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), Orbitrap mass spectrometry (Orbitrap MS), and gas chromatography–mass spectrometry (GC–MS). Isolation of ketones was carried out by a chemical derivatization process with Girard T reagent and followed by a hydrolysis process of the derivatives. The Girard T reagent reacted with ketones under weakly acidic conditions and introduced a charged quaternary ammonium moiety on carbonyl to form water-soluble hydrazones, which can be separated from a complex matrix through an extrography separation and have a strong response in a positive-ion electrospray ionization (ESI) source for mass spectrometric analysis. The isolated derivatives were reversibly turned into the original ketones to selectively separate long alkyl ketones from aromatic ketones with alkyl substituents of C0–C4. The ketones were assigned to 12 class species by high-resolution MS analysis: O1–5 (refers that there are 1–5 oxygen atoms in the molecules), O1S1, N1O1–4, and N2O1–2, among which the O1 class species was the most abundant. The long-chain alkyl ketones, such as aliphatic 2-, 3-, and 4-ketones, alkylcyclopentanones, alkyl phenyl ketones, and aromatic ketones (such as indanone, cyclopentenone, tetralone, acetonaphthone, dihydrophenanthrenone, benzophenone, fluorenone, fluorenyl formaldehyde, anthrone, anthracene formaldehyde, acetylanthracene, acetylphenanthrene, acetylfluorene, benzofluorenone, etc.), were detected by GC–MS. In addition, C18-isoprenoid methyl ketone and tricyclic terpenoids and steroids with one or two oxygen atoms were found in the coal tar.Chen, X.X., Yu, S.Y., Underhill Anne, P., Fang, H., 2018. Radiocarbon dating and stable carbon isotopic analyses of Neolithic and Bronze Age staple crops in the lower Yellow River area and their paleodietary implications. Geoarchaeology 33, 307-313. stable carbon isotope ratio of archaeological human skeletons has been increasingly used to reconstruct paleodiet, which in turn may provide deep insight into the origin and spread of agriculture. However, little is known about the spatial and temporal variability of some staple crops in many areas of the world. Here, we present radiocarbon ages and stable carbon isotope data of charred millet and rice grains from 14 Neolithic and Bronze Age archaeological sites in the lower Yellow River area, a region which has not been adequately considered. The mean δ13C value of prehistoric millet grains is ?9.13‰, which is ca. 2‰ higher than that of modern millet grains. The mean δ13C value of prehistoric rice grains is ?24.14‰, which is very close to that of modern rice grains. Our study not only provides updated information that facilitates a more precise reconstruction of human paleodiet based on δ13C analysis of skeletal remains, but also supports previous conclusions that C4 plants can be used as a reliable proxy for atmospheric carbon isotopic composition. Chen, Y., Qin, Y., Wei, C., Huang, L., Shi, Q., Wu, C., Zhang, X., 2018. Porosity changes in progressively pulverized anthracite subsamples: Implications for the study of closed pore distribution in coals. Fuel 225, 612-622. samples for low-pressure nitrogen (N2) adsorption measurement in previous work cover a large particle size range (from 0.075 to 4.75?mm). However, minimal attention has been paid to the effect of coal particle size on pore structure using gas adsorption methods. Anthracite coal collected from the Zhina Coalfield, China, was crushed, subsampled, and sieved to eight particle size ranges: 1–2?mesh (8000–25400??m), 40–50?mesh (270–380??m), 50–70?mesh (212–270??m), 70–90 mesh (160–212??m), 90–160?mesh (96–160??m), 160–200?mesh (75–96??m), 200–300?mesh (48–75??m), and >300?mesh (<48??m). The adsorption–desorption isotherms of each subsample were measured using N2 at 77.35?K to compare differences in pore structure characteristics. The results of the N2 adsorption tests show that particle size has a significant effect on pore volume, specific surface area, and pore size distribution of coal. Specifically, decreasing coal particle size results in continuous increase in macro- and mesopore volumes and specific surface areas. This can be attributed to the fact that smaller-sized coal particles open more of the previously closed pores, which are then accessible to adsorping gas. The contribution of closed pores to the total pore volume is 94.94% in the pore aperture range of 3.1–370?nm. The volume of closed macropores varies from 48.96 to 84.69% of the total closed pore volume. According to optical microscope and SEM observations of the Zhina Coalfield subsamples, massive gas pores exist in an isolated form with poor connectivity; some plant tissue pores are filled by pyrites and clay minerals, and may be totally occluded. Thus, gas pores contribute the dominant amount of the closed pore volume. In addition, different Zhina Coalfield subsamples show varied hysteresis loop shapes, indicating that closed pores in coal possess a variety of pore morphologies and sizes. To improve the accuracy and comparability of the pore structure of coal, we propose >300 mesh as the preferred particle size of coal for all low-pressure N2 adsorption measurement in future work. Furthermore, caution must be used in evaluating coal bed methane resource recovery potential as coal possesses high closed porosity; failure to account for this will result in an overestimation of the amount of gas that can be recovered from coal seams during production.Cheng, B., Tan, W., Wu, Z., Chen, Z., 2018. Polycyclic aromatic hydrocarbon in solid reservoir bitumen from the central Sichuan Basin. Petroleum Science and Technology 36, 875-881. aromatic hydrocarbons in solid bitumen from the central Sichuan Basin have been investigated. Several compounds including fluoranthene (Fl), pyrene (Py), benz[a]anthracene (BaA), chrysene (Chy), benzofluoranthenes (BFl), and benzopyrenes (BePy) are found to have enhanced concentrations in several samples. Abnormally high values of the Fl/(Fl + Py), BaA/(BaA + Chy), and BFl/(BFl + BPy) ratios are also observed. In addition, they have parent aromatic compounds that are considerably more abundant than their alkyl homologues. These features indicate that formation of the solid bitumen is probably related to abnormal heating, which may be induced by hydrothermal activity.Chhun, C., Kioka, A., Jia, J., Tsuji, T., 2018. Characterization of hydrate and gas reservoirs in plate convergent margin by applying rock physics to high-resolution seismic velocity model. Marine and Petroleum Geology 92, 719-732. hydrates are widely distributed in the Kumano forearc basin, which is located above accretionary prism in the Nankai margin off the Kii peninsula, Japan. Bottom-Simulating Reflector (BSR) at the base of gas hydrate stability zone has been imaged as a strong acoustic impedance contrast on the reflection seismic profiles. In order to better define the accumulations of gas hydrates and free gases, we performed a high-resolution seismic velocity analysis to 3D seismic data using a method of conventional semblance spectra via automatic velocity picking algorithm. The results revealed that gas hydrate-bearing sediments above the BSR and free gas-bearing sediments below the BSR are characterized by P-wave velocities of 1900–2500?m/s and 1000–1800?m/s, respectively. Then, the velocity model was converted into gas hydrate and free gas saturation using rock physics approaches. The results indicated that saturation of gas hydrates ranges from 0% to 45% in the pore space, and highly concentrated around the outer ridge where faults are densely developed. Additionally, concentrations of free gas ranging from 0% to 20% in the pore space are widely distributed below BSRs and are considerably high above ridge structure generated by displacement of large fault splayed from the deep plate boundary décollement. Based on these results, we suggest that the gas hydrates concentrated due to the free gas influx which migrated upward through the steeply dipping strata and faults (or fractures) cutting through the basin. The accumulations of gas and/or hydrates are further controlled by fault movements in the accretionary prism beneath the forearc basin. Therefore, these factors generated by intensive tectonic movements in the plate subduction zone control the distribution and saturation pattern of gas hydrate and free gas formations.Cirilli, S., Panfili, G., Buratti, N., Frixa, A., 2018. Paleoenvironmental reconstruction by means of palynofacies and lithofacies analyses: An example from the Upper Triassic subsurface succession of the Hyblean Plateau Petroleum System (SE Sicily, Italy). Review of Palaeobotany and Palynology 253, 70-87. combined palynofacies and lithofacies analysis was carried out on two borehole successions (Streppenosa 1 and Bimmisca 1) from the Hyblean Plateau Petroleum System (SE Sicily, Italy). It was found that both the wells penetrated the most important source and seal rocks of the Sicilian region (Noto and Streppenosa formations), previously assigned to the Late Triassic-Early Jurassic, deposited within a carbonate platform-basin system. Based on new palynological data, the organic rich succession (Noto Formation and Upper Streppenosa Member) can now be entirely assigned to the Rhaetian, thus constraining its deposition to a time interval characterized by increasing global humidity and seasonality. The integrated palynofacies and lithofacies data enabled characterization of the timing of the drowning phases of the carbonate platform-basin system as being controlled by relative sea level changes mostly triggered by the Triassic extensional tectonic activity. During the first phase of the relative sea-level rise, clayey and organic-rich sediments were deposited only in the deepest portion of the basin. As the sea level continued to rise, the entire system drowned completely and suboxic-anoxic basinal sediments were deposited across the whole Hyblean region, onlapping the shallow-water facies. In the meantime increasing global humidity contributed to an increased freshwater input in the marine depositional system as documented by the presence of fern spores and clay. It caused water stratification and subsequent anoxia at marine basins, favoring the preservation of sedimentary organic matter. This atmospheric change could be related to the degassing of the Central Atlantic Magmatic Province.Clark, J.B., Long, W., Tzortziou, M., Neale, P.J., Hood, R.R., 2018. Wind-driven dissolved organic matter dynamics in a Chesapeake Bay tidal marsh-estuary system. Estuaries and Coasts 41, 708-723. on organic matter cycling across the tidal wetland-estuary interface have proved elusive, but high-resolution observations coupled with process-based modeling can be a powerful methodology to address shortcomings in either methodology alone. In this study, detailed observations and three-dimensional hydrodynamic modeling are used to examine biogeochemical exchanges in the marsh-estuary system of the Rhode River, MD, USA. Analysis of observations near the marsh in 2015 reveals a strong relationship between marsh creek salinity and dissolved organic matter fluorescence (fDOM), with wind velocity indirectly driving large amplitude variation of both salinity and fDOM at certain times of the year. Three-dimensional model results from the Finite Volume Community Ocean Model implemented for the wetland system with a new marsh grass drag module are consistent with observations, simulating sub-tidal variability of marsh creek salinity. The model results exhibit an interaction between wind-driven variation in surface elevation and flow velocity at the marsh creek, with northerly winds driving increased freshwater signal and discharge out of the modeled wetland during precipitation events. Wind setup of a water surface elevation gradient axially along the estuary drives the modeled local sub-tidal flow and thus salinity variability. On sub-tidal time scales (>36?h, <1?week), wind is important in mediating dissolved organic matter releases from the Kirkpatrick Marsh into the Rhode River.Clery, D., 2018. Alpha Centauri's siren call has frustrated planet hunters. Science 360, 138. Centauri, a three-star system just 4 light-years away that is the sun's nearest neighbor, ought to be a great place to look for Earth-like planets. But last week, at a meeting of the European Astronomical Society (EAS) here, astronomers lamented the way the system has thwarted discovery efforts so far—and announced new efforts to probe it. “It's very likely that there are planets,” says Pierre Kervella of the Paris Observatory in Meudon, France, but the nature and positions of the stars complicate the search. “It's a little frustrating for planet searchers.”The system's two sunlike stars, Alpha Centauri A and B, orbit each other closely while Proxima Centauri, a tempestuous red dwarf, hangs onto the system tenuously in a much more distant orbit. In 2016, astronomers discovered an Earth-mass planet around Proxima Centauri (Science, 26 August 2016, p. 857), but the planet, blasted by radiation and fierce stellar winds, seems unlikely to be habitable. Astrobiologists think the other two stars are more likely to host temperate, Earth-like planets.Maksym Lisogorskyi, an astronomer at the University of Hertfordshire in Hatfield, U.K., tried to find them with an instrument on the European Southern Observatory's (ESO's) 3.6-meter telescope in Chile. He and his colleagues looked for Doppler shifts in the spectral lines of the stars' light that would be caused if a planet tugged them back and forth. But Lisogorskyi told the meeting that the stars' surfaces are turbulent, and prone to flares that also jiggle the spectral lines, masking the subtle signals from any Earth-size planets. “The lines do all kinds of things,” he says. Although Alpha Centauri has been a primary target for the planet-finding instrument since it was inaugurated in 2005, it has seen nothing so far.Also hampering observations are the current positions of the two stars. As viewed from Earth, they are very close together, making them harder to study individually, Lily Zhao of Yale University told the meeting. More precise observations should become possible as their 80-year orbit carries them farther apart. In the meantime, Zhao and her colleagues have succeeded in ruling out the presence of giant planets around either star, based on a decade's worth of data from three instruments on different telescopes. “There are no Jupiters in the system, but there may be plenty of Earth-sized planets still to discover,” she said.In a binary system like Alpha Centauri the lack of giant planets in Jupiter-like orbits is no surprise, because the gravity of each star would tend to kick any such planets orbiting the other star out of the system, Kervella says. But he says that temperate planets in the habitable zone, closer in, would be immune to these perturbations. A chance to get a close look is coming soon: Kervella's team mapped out the system's trajectory and found that in a decade, Alpha Centauri A will pass in front of a more distant star and act as a gravitational lens, distorting the light of the star behind it. How the light from the distant star flickers and mutates over time will provide a wealth of information about any inner planets. By that time, ESO's 39-meter Extremely Large Telescope is expected to be operating and capable of observing the distortion in detail. “We will see all the planets, big and small,” says astronomer Hans-Ulrich K?ufl of ESO in Garching, Germany.The privately funded Breakthrough Initiatives wants an even closer look. In 2016, the organization announced its Starshot program, a $100 million effort to equip a microchip-size spacecraft with a camera and light-sails. A blast of photons from a giant ground-based laser would accelerate the craft to 20% of the speed of light, allowing it to make the 4-light-year trip in 20 years. During a flyby that might last only seconds, it would snap close-ups of the Alpha Centauri planets—assuming they exist.Finding targets for the Starshot is one aim of a Breakthrough-funded effort that ESO announced last year: adapting an existing instrument on the Very Large Telescope in Chile to directly image possible planets. Called VISIR, the instrument will be equipped with a coronagraph—a mask to block out the light of the star so that the much fainter planets can be seen. VISIR observes in the midinfrared, an advantage for imaging a temperate planet because the disparity in brightness between the dim planet and its brilliant parent star is smaller in this part of the spectrum. The ESO team is testing the hardware and hopes to start observing in mid-2019 with 100 hours of dedicated telescope time.Others at the EAS meeting think the fastest and cheapest way to detect an Earth-like planet around either of the sunlike stars is with a space telescope. A privately backed organization called Project Blue is seeking $70 million to build and launch a 50-centimeter telescope that would stare at Alpha Centauri. Last year, the project raised $150,000 through crowdfunding to design the spacecraft. Franck Marchis, an astronomer at the SETI Institute in Mountain View, California, a partner with Project Blue, says such a telescope, outfitted with a coronagraph, would be able to obtain an image. “It's doable. The technology is there,” Marchis said. “The goal is to image a pale blue dot.”Conlette, O.C., Emmanuel, N.E., Olukayode, A.O., 2018. Factors that influence methanogenic activities in a low sulfate oil-producing facility. Petroleum Science and Technology 36, 688-695. analysis of a low sulfate oil bearing environment was carried out using 16S rRNA gene sequencing technique and the effects of some environmental factors like pH, temperature, salinity on methane production and corrosion rates were determined. Pyrosequenced data revealed dominance of hydrogenotrophic (Methanobacterium) and Methylotrophic (Methanolobus) in samples. Results showed that samples had their optimal temperature for maximum methane production at 35–40oC and higher temperature (55oC) was inhibitory to methane production. Methanogens in samples produced methane over a wide pH range but the pH optima for maximum methane production ranged between 6 and 7. Sodium chloride was tolerated better at lower concentrations (< 200 mM), higher concentrations (>300 mM) drastically inhibited methane formation, an indication that the methanogens involved are not halophytes. Because different methanogens require different substrates and reacts to changes in environmental conditions, environmental factors may indirectly control the diversity and activity of methanogens in low sulfate oil bearing environments.Cordeiro, L.G.M.S., Wagener, A.L.R., Carreira, R.S., 2018. Organic matter in sediments of a tropical and upwelling influenced region of the Brazilian continental margin (Campos Basin, Rio de Janeiro). Organic Geochemistry 120, 86-98. biomarkers [fatty acids (FAs), sterols and alcohols] and carbon stable isotopes (δ13C values) in surface sediments from 9 cross shelf transects (25–3000?m water depth) from the Campos Basin, SE Brazilian continental margin were analyzed. The aim was to investigate the link between the prevailing regional specific oceanographic conditions (upwelling events, intrusion of cold and nutrient-rich water, low river input) and the nature and distribution of organic matter (OM) in the basin. A general predominance of OM from autochthonous processes, but with a relevant spatial gradient in the quality and quantity of the sedimentary OM, was observed. On the shelf (<150?m), concentrations of lipids were usually low, except in areas influenced by upwelling, but the presence of labile compounds suggested the occurrence of fresh OM in the sediment. The export of continental OM was observed only in shelf sediments near the Paraíba do Sul River. The upper and middle slope (400–1300?m) exhibited the highest concentrations of total organic carbon (TOC) and lipids, but lipid biomarkers suggested the presence of OM with a high degree of bacterial degradation. This may result from the export of material from shallow areas, possibly due to the action of eddies and meandering of the Brazil Current and bottom currents in the region. On the lower slope (1900–3000?m), only the more recalcitrant compounds were above detection limit. The presence of labile lipids in high amount in the shelf and slope suggests the presence of OM with a high potential for supplying the food requirements of heterotrophic organisms in the sediment, which may in turn have a major influence on the ecology of benthic communities.Cowton, L.R., Neufeld, J.A., White, N.J., Bickle, M.J., Williams, G.A., White, J.C., Chadwick, R.A., 2018. Benchmarking of vertically-integrated CO2 flow simulations at the Sleipner Field, North Sea. Earth and Planetary Science Letters 491, 121-133. modeling plays an essential role in both identifying and assessing sub-surface reservoirs that might be suitable for future carbon capture and storage projects. Accuracy of flow simulations is tested by benchmarking against historic observations from on-going CO2 injection sites. At the Sleipner project located in the North Sea, a suite of time-lapse seismic reflection surveys enables the three-dimensional distribution of CO2 at the top of the reservoir to be determined as a function of time. Previous attempts have used Darcy flow simulators to model CO2 migration throughout this layer, given the volume of injection with time and the location of the injection point. Due primarily to computational limitations preventing adequate exploration of model parameter space, these simulations usually fail to match the observed distribution of CO2 as a function of space and time. To circumvent these limitations, we develop a vertically-integrated fluid flow simulator that is based upon the theory of topographically controlled, porous gravity currents. This computationally efficient scheme can be used to invert for the spatial distribution of reservoir permeability required to minimize differences between the observed and calculated CO2 distributions. When a uniform reservoir permeability is assumed, inverse modeling is unable to adequately match the migration of CO2 at the top of the reservoir. If, however, the width and permeability of a mapped channel deposit are allowed to independently vary, a satisfactory match between the observed and calculated CO2 distributions is obtained. Finally, the ability of this algorithm to forecast the flow of CO2 at the top of the reservoir is assessed. By dividing the complete set of seismic reflection surveys into training and validation subsets, we find that the spatial pattern of permeability required to match the training subset can successfully predict CO2 migration for the validation subset. This ability suggests that it might be feasible to forecast migration patterns into the future with a degree of confidence. Nevertheless, our analysis highlights the difficulty in estimating reservoir parameters away from the region swept by CO2 without additional observational constraints.Craddock, P.R., Bake, K.D., Pomerantz, A.E., 2018. Chemical, molecular, and microstructural evolution of kerogen during thermal maturation: Case study from the Woodford Shale of Oklahoma. Energy & Fuels 32, 4859-4872. elemental, spectroscopic (infrared spectroscopy and X-ray absorption near-edge structure), and gas intrusion (helium pycnometry and nitrogen adsorption) analyses are used to characterize the bulk chemical, molecular, and physical microstructures of kerogen spanning a thermal maturity transect (vitrinite reflectance, Ro, from 0.5% to 2.6%) across the Woodford Shale of the Anadarko Basin, Oklahoma. The integration takes advantage of novel procedures to prepare kerogen isolates that preserve both the chemical and physical properties of the organic matter in the bulk shale. The Woodford kerogens follow the expected trends in H/C and O/C coordinates during thermal maturation for type II kerogen. Infrared spectra show that loss of hydrogen from kerogen is related to cracking of hydrogen-rich aliphatic (alkyl) carbon structures from aromatic carbons. Within the range of Ro values < 1.5%, peripheral aromatic carbons remain highly substituted with alkyl (methyl and methylene) and probably heteroatom functional groups. At Ro values > 1.5%, these substitutions are substantially removed and replaced by hydrogen. The evolution of carbon structures inferred from the IR spectra is supported by known carbon bond dissociation energies for carbonaceous materials. Total organic sulfur and sulfur-XANES data show that sulfur in Woodford kerogens is dominated by aromatic sulfur (thiophene) and that reactive, aliphatic sulfur (sulfide) is eliminated at low degrees of thermal stress (Ro ≤ 0.9%). At higher thermal stress, sulfur speciation is stable and dominated by thermally stable thiophene. The physical properties of Woodford kerogens evolve during thermal maturation in a manner consistent with their molecular characteristics. Skeletal density of kerogen increases during maturation in a manner that is linearly correlated to its atomic H/C ratio and inferred aromatic carbon content. The specific surface area of kerogen also increases during maturation, reflecting the development of internal pores within the kerogen skeletal framework as aliphatic carbon structures are preferentially cracked and expelled from solid kerogen. The quantitative chemical and structural changes expressed by the Woodford kerogens during thermal maturation, including their hydrogen and carbon content, carbon speciation, and skeletal density, are shown by comparison to not be measurably different for other type II kerogens from numerous oil- and gas-producing shale plays, indicating that thermal stress acts to drive maturation of type II kerogen in a similar way globally.Crepier, J., Le Masle, A., Charon, N., Albrieux, F., Duchene, P., Heinisch, S., 2018. Ultra-high performance supercritical fluid chromatography hyphenated to atmospheric pressure chemical ionization high resolution mass spectrometry for the characterization of fast pyrolysis bio-oils. Journal of Chromatography B 1086, 38-46. characterization of complex mixtures requires the combination of powerful analytical techniques. A Supercritical Fluid Chromatography (SFC) method was previously developed, for the specific case of fast pyrolysis bio oils, as an alternative to gas chromatography (GC and GC?×?GC) or liquid chromatography (LC and LC?×?LC), both separation methods being generally used prior to mass spectrometry (MS) for the characterization of such complex matrices. In this study we investigated the potential of SFC hyphenated to high resolution mass spectrometry (SFC-HRMS) for this characterization using Negative ion Atmospheric Pressure Chemical ionization ((?)APCI) for the ionization source. The interface between SFC and (?)APCI/HRMS was optimized from a mix of model compounds with the objective of maximizing the signal to noise ratio. The main studied parameters included both make-up flow-rate and make-up composition. A methodology for the treatment of APCI/HRMS data is proposed. This latter allowed for the identification of molecular formulae. Both SFC-APCI/HRMS method and data processing method were applied to a mixture of 36 model compounds, first analyzed alone and then spiked in a bio-oil. In both cases, 19 compounds could be detected. Among them 9 could be detected in a fast pyrolysis bio-oil by targeted analysis. The whole procedure was applied to the characterization of a bio-oil using helpful representations such as mass-plots, van Krevelen diagrams and heteroatom class distributions. Finally the results were compared with those obtained with a Fourier Transform ion-cyclotron resonance mass spectrometer (FT-ICR/MS).Curson, A.R.J., Williams, B.T., Pinchbeck, B.J., Sims, L.P., Martínez, A.B., Rivera, P.P.L., Kumaresan, D., Mercadé, E., Spurgin, L.G., Carrión, O., Moxon, S., Cattolico, R.A., Kuzhiumparambil, U., Guagliardo, P., Clode, P.L., Raina, J.-B., Todd, J.D., 2018. DSYB catalyses the key step of dimethylsulfoniopropionate biosynthesis in many phytoplankton. Nature Microbiology 3, 430-439. (DMSP) is a globally important organosulfur molecule and the major precursor for dimethyl sulfide. These compounds are important info-chemicals, key nutrients for marine microorganisms, and are involved in global sulfur cycling, atmospheric chemistry and cloud formation. DMSP production was thought to be confined to eukaryotes, but heterotrophic bacteria can also produce DMSP through the pathway used by most phytoplankton, and the DsyB enzyme catalysing the key step of this pathway in bacteria was recently identified. However, eukaryotic phytoplankton probably produce most of Earth’s DMSP, yet no DMSP biosynthesis genes have been identified in any such organisms. Here we identify functional dsyB homologues, termed DSYB, in many phytoplankton and corals. DSYB is a methylthiohydroxybutryate methyltransferase enzyme localized in the chloroplasts and mitochondria of the haptophyte Prymnesium parvum, and stable isotope tracking experiments support these organelles as sites of DMSP synthesis. DSYB transcription levels increased with DMSP concentrations in different phytoplankton and were indicative of intracellular DMSP. Identification of the eukaryotic DSYB sequences, along with bacterial dsyB, provides the first molecular tools to predict the relative contributions of eukaryotes and prokaryotes to global DMSP production. Furthermore, evolutionary analysis suggests that eukaryotic DSYB originated in bacteria and was passed to eukaryotes early in their evolution.Curtis, D., Elango, V., Collins, A.W., Rodrigue, M., Pardue, J.H., 2018. Transport of crude oil and associated microbial populations by washover events on coastal headland beaches. Marine Pollution Bulletin 130, 229-239. transport of MC252 oil, sand and shell aggregates was studied on a low-relief coastal headland beach in Louisiana, USA including measurement of alkylated PAHs and Illumina sequencing of intra-aggregate microbial populations. Weathering ratios, constructed from alkylated PAH data, were used to assess loss of 3-ring phenanthrenes and dibenzothiophenes relative to 4-ring chrysenes. Specific aggregate types showed relatively little weathering of 3-ring PAHs referenced to oil sampled near the Macondo wellhead with the exception of certain SRBs sampled from the supratidal environment and samples from deposition areas north of beach. Aggregates mobilized by these storm-driven washover events contains diverse microbial populations dominated by the class Gammaproteobacteria including PAH-degrading genera such as Halomonas, Marinobacter and Idiomarina. Geochemical assessment of porewater in deposition areas, weathering observations, and microbial data suggest that storm remobilization can contribute to susceptibility of PAHs to biodegradation by moving oil to beach microenvironments with more favorable characteristics. (149).Dai, G., Zou, Q., Wang, S., Zhao, Y., Zhu, L., Huang, Q., 2018. Effect of torrefaction on the structure and pyrolysis behavior of lignin. Energy & Fuels 32, 4160-4166. influences of torrefaction on the structure and pyrolysis behavior of lignin were investigated in this study. After torrefaction, the oxygen content of lignin was reduced, which led to the increase of its high heating value. The main reactions occurring during torrefaction were the cleavage of aryl ether linkages, demethoxylation, and dissociation of the aliphatic side chain, as indicated by Fourier transform infrared spectroscopy analysis. The distributed activation energy model with double combined Gaussian functions was adopted to analyze the pyrolysis kinetics of lignin. It was found that torrefaction increased the activation energy for degradation and condensation reactions. The devolatilization contribution of condensation reactions increased as well after torrefaction. Torrefaction also had a great effect on the pyrolytic product distribution of lignin. The yields of non-methoxylated phenols and phenols without a propyl side chain increased after torrefaction.Darvish, H., Raji Asadabadi, H., Maleki Sadeghi, A., Rouhibakhsh, k., 2018. Application of Grid partitioning based Fuzzy inference system method as a novel approach for prediction of interfacial tension of hydrocarbon and carbon dioxide. Petroleum Science and Technology 36, 660-665. the importance of enhanced oil recovery (EOR) processes increases because of increasing demand of energy and declination of oil reservoirs. Due to this fact the researchers attracted to study performance of EOR methods. one of the high efficient methods is carbon dioxide injection which is favorable because of low cost and environmental friendly viewpoints. One of important parameters which have straight effect on recovery of injection is interfacial tension between carbon dioxide and hydrocarbons. In the present investigation the main objective is proposing the Grid partitioning based Fuzzy inference system method as novel approach to predict interfacial tension of carbon dioxide and hydrocarbon in terms of temperature, pressure, liquid and gas densities and molecular weight of alkane. The coefficients of determination for different datasets of training and testing of estimating algorithm are determined as 0.9919 and 0.9899. This results express the algorithm has potential of estimating interfacial tension of hydrocarbons and carbon dioxide.Davín, A.A., Tannier, E., Williams, T.A., Boussau, B., Daubin, V., Sz?ll?si, G.J., 2018. Gene transfers can date the tree of life. Nature Ecology & Evolution 2, 904-909. has always been predominantly microbial, and the scarcity of fossils from bacteria, archaea and microbial eukaryotes has prevented a comprehensive dating of the tree of life. Here, we show that patterns of lateral gene transfer deduced from an analysis of modern genomes encode a novel and abundant source of information about the temporal coexistence of lineages throughout the history of life. We use state-of-the-art species tree-aware phylogenetic methods to reconstruct the history of thousands of gene families and demonstrate that dates implied by gene transfers are consistent with estimates from relaxed molecular clocks in Bacteria, Archaea and Eukarya. We present the order of speciations according to lateral gene transfer data calibrated to geological time for three datasets comprising 40 genomes for Cyanobacteria, 60 genomes for Archaea and 60 genomes for Fungi. An inspection of discrepancies between transfers and clocks and a comparison with mammalian fossils show that gene transfer in microbes is potentially as informative for dating the tree of life as the geological record in macroorganisms.Davudov, D., Moghanloo, R.G., Lan, Y., 2018. Evaluation of accessible porosity using mercury injection capillary pressure data in shale samples. Energy & Fuels 32, 4682-4694. present a novel approach to correct accessible/fluid-saturated porosity values calculated using mercury injection capillary pressure (MICP) for shale samples. On the basis of recent studies, accessible porosity of shale samples calculated from the MICP test is corrected to consider conformance and grain compressibility. However, we show here that the shale samples experience an additional phenomenon during the MICP test that has not yet been addressed, i.e., compression of inaccessible/unfilled pores. Therefore, we propose a general approach consisting of three distinct corrections to accurately estimate accessible porosity of the shale sample using MICP data: (1) conformance, (2) grain compressibility, and (3) inaccessible pore compressibility. First, we develop a mathematical model to estimate both pore and grain compressibility using MICP data and then calculate accessible porosity using the above-mentioned corrections. In the mathematical formulation, we divide the shale matrix into three constituents: (1) accessible pores, (2) inaccessible pores, and (3) grains. We, then, estimate volume fractions for each stage using MICP test data. Samples from both Barnett and Haynesville shale plays (11 samples for each shale plays) are used to perform our study and validate the hypothesis. Moreover, the impact of newly proposed corrections on petrophysical properties, such as permeability and pore size distribution, is evaluated. Our results suggest that estimated accessible porosity significantly decreases when new corrections are implemented on the MICP test data. Furthermore, the results suggest that inclusion of correction will shift pore size distribution toward smaller pores and can also dramatically reduce permeability estimations down to 2 orders of magnitude smaller than the original values. The outcome of this study can help determine the fraction of accessible porosity for reserve evaluation purposes in shale plays.de Carvalho, C.C.C.R., 2018. Marine biofilms: A successful microbial strategy with economic implications. Frontiers in Marine Science 5, 126. doi: 10.3389/fmars.2018.00126. and other microorganisms have evolved an ingenious form of life, where they cooperate and improve their chances of survival when subjected to environmental stress, called biofilms. In these communities of adhered cells, bacteria are protected by a matrix of extracellular polymeric substances that provide protection against e.g. temperature and pH fluctuations, UV exposure, changes in salinity, depletion of nutrients, antimicrobial compounds and predation. Their success in marine environments and the number of bacterial cells in the sea, allow them to colonize nearly all man-made surfaces in contact with seawater. The costs to maritime transport, aquaculture, oil and gas industries, desalination plants and other industries are significant which has led to the development of various strategies to prevent biofilm formation and cleaning of infected surfaces. In this review, the benefits for bacterial cells to live in biofilms and the consequences to human activities are discussed.De la Torre, G.G., Garcia, M.A., 2018. The cosmic gorilla effect or the problem of undetected non terrestrial intelligent signals. Acta Astronautica 146, 83-91. article points to a long lasting problem in space research and cosmology, the problem of undetected signs of non terrestrial life and civilizations. We intentionally avoid the term extraterrestrial as we consider other possibilities that may arise but not fall strictly within the extraterrestrial scope. We discuss the role of new physics including dark matter and string theory in the search for life and other non terrestrial intelligence. A new classification for non terrestrial civilizations with three types and five dimensions is also provided. We also explain how our own neurophysiology, psychology and consciousness can play a major role in this search of non terrestrial civilizations task and how they have been neglected up to this date. To test this, 137 adults were evaluated using the cognitive reflection test, an attention/awareness questionnaire and a visuospatial searching task with aerial view images to determine the presence of inattentional blindness.de Lannoy, C.-F., Eisaman, M.D., Jose, A., Karnitz, S.D., DeVaul, R.W., Hannun, K., Rivest, J.L.B., 2018. Indirect ocean capture of atmospheric CO2: Part I. Prototype of a negative emissions technology. International Journal of Greenhouse Gas Control 70, 243-253. present the design, construction, characterization, and analysis of a prototype process for a novel electrochemical platform of candidate negative emissions technologies (NETs), termed indirect ocean capture. The IOC technologies remove carbon dioxide gas from the atmosphere by leveraging both air-ocean gas exchange and the pH sensitivity of the ocean’s carbonate buffer system. The system characterized in this paper enables two configurations that capture CO2 either as a pure gas or as a solid mineral. Both configurations use the acid and base produced by the membrane electrodialysis of ocean water. The first configuration, termed the ‘acid process’, acidifies ocean water or brine to shift the carbonate buffer system towards dissolved CO2 gas, which is vacuum stripped from the acidified brine. The second configuration, termed the ‘base process’, adds base to the brine to shift the carbonate buffer system towards carbonate ions, which precipitates as CaCO3. A closed loop cycle is achieved by returning this decarbonized and alkalinized brine to the ocean for additional CO2 absorption from the air. Our evaluation of this prototype scale system focused on the parameters that have the most influence on the ultimate cost of the extracted CO2. In a concurrent techno-economic study, the most cost-sensitive parameters were shown to be the efficiencies of the anion and cation exchange membranes, the number and orientation of CO2 extraction membranes, and the volume of base required for CaCO3 precipitation. The measured parameters provide target values for commercial deployment. The experiments in this study were used to inform the concurrent techno-economic study that quantifies in detail the projected cost of avoided CO2 achievable with this process.Deaf, A.S., Tahoun, S.S., 2018. Integrated palynological, organic geochemical, and sequence stratigraphic analyses of the middle to upper Cenomanian hydrocarbon reservoir/source Abu Roash “G” Member: A depositional model in northwestern Egypt. Marine and Petroleum Geology 92, 372-402. current investigation provides further insight into the petroliferous characteristics of the Abu Roash “G” Member, which is regarded as an important rock unit for the Egyptian oil industry. Forty-seven samples covering the “G” Member were selected from the BED 14-1 and BED 2-4 wells in the Abu Gharadig Basin and from the Abu Tunis 1X well in the Matruh Basin, both of which are located in the north Western Desert. An independent dating of the “G” rocks of BED 2-4 by benthic foraminifera and ostracods, in addition to palynological dating, suggests a middle-late Cenomanian age and provides the biochronostratigraphic framework for the sequence stratigraphic analysis.Analysis of the vertical distribution of particulate organic matter defines three palynofacies types (PF). PF-1 represents the basal “G”, where shales of the BED wells and calcareous shale of Abu Tunis 1X were deposited during a relative sea level rise in an outer middle shelf environment that experienced a notable high primary productivity. Prevailing reducing (suboxic-anoxic) conditions supported preservation of very high amounts of amorphous organic matter (AOM) in PF-1. PF-2 is equated to shales of the middle “G” of BED 14-1 and BED 2-4 and to calcareous shales and limestone of the upper “G” in Abu Tunis 1X. PF-2 was deposited during a relative sea level fall in an inner middle shelf setting under better-developed suboxic-anoxic conditions. PF-3 corresponds to the upper “G” of BED 14-1 and BED 2-4 and represents the shallowest setting, where sandy and silty shales were deposited during a pronounced sea level fall in an inner shelf environment. The same suboxic-anoxic conditions were prevailing during deposition of PF-3. Three bioevents were recorded, which could be of palaeoecological and/or biostratigraphic significance. These are Senegalinium aenigmaticum-Dinopterygium cladoides peak, Dinopterygium cladoides-Dinopterygium alatum peak, and an acme of Classopollis brasiliensis. Sequence stratigraphy of a transect of the four studied sections was carried out to understand the response of the particulate organic matter distribution and depositional system to the sea level changes. Three third-order, depositional genetic sequences were recognized and correlated with the global sea level curve (KCe 2, KCe 3, and KCe 4). The early highstand systems tract (eHST) of the genetically related KCe 3 in all wells is characterized by relatively rich organic matter, where combined remarkably low water circulation and insignificant dilution of organic matter with coarse terrigenous material probably supported good preservation of organic matter.Spatial distribution of the “G” rocks shows lateral facies changes. This was inferred from sedimentation of an organic-poor (avg. 0.8 TOC wt %), coarse clastic (sandy shales) facies in the studied area in Abu Gharadig Basin. Sedimentation changes laterally into a northeast and northwest organic-rich, finer clastic (shale, calcareous shales, and argillaceous limestone) facies in the western Matruh Basin. The robust anoxic conditions and very low dilution of organic matter by terrigenous influx enhanced the organic richness (avg. 2.4 TOC wt %) of these rocks, which resulted in the formation of promising hydrocarbon source rocks. Thus, for a successful hydrocarbon exploration in the north Western Desert, the promising source section of the “G” Member would be associated with shales, calcareous shales, and argillaceous limestone lithologies. Its depositional environment is mainly confined to outer middle and inner middle shelf settings that have widespread suboxic-anoxic conditions and show eHST pattern. In contrast, the regressive intervals that are denoted by the lowstand systems tract (LST) and/or the late HST (lHST) typify the relatively coarse clastics as good quality reservoir rocks that are characterized by poor organic richness due to dilution with terrigenous influx.Deino, A.L., Behrensmeyer, A.K., Brooks, A.S., Yellen, J.E., Sharp, W.D., Potts, R., 2018. Chronology of the Acheulean to Middle Stone Age transition in eastern Africa. Science 360, 95-98.. The origin of the Middle Stone Age (MSA) marks the transition from a highly persistent mode of stone toolmaking, the Acheulean, to a period of increasing technological innovation and cultural indicators associated with the evolution of Homo sapiens. We used argon-40/argon-39 and uranium-series dating to calibrate the chronology of Acheulean and early MSA artifact–rich sedimentary deposits in the Olorgesailie basin, southern Kenya rift. We determined the age of late Acheulean tool assemblages from 615,000 to 499,000 years ago, after which a large technological and faunal transition occurred, with a definitive MSA lacking Acheulean elements beginning most likely by ~320,000 years ago, but at least by 305,000 years ago. These results establish the oldest repository of MSA artifacts in eastern Africa.Editor's Summary: The Middle Stone Age in Africa. The Olorgesailie basin in the southern Kenya rift valley contains sediments dating back to 1.2 million years ago, preserving a long archaeological record of human activity and environmental conditions. Three papers present the oldest East African evidence of the Middle Stone Age (MSA) and elucidate the system of technology and behavior associated with the origin of Homo sapiens. Potts et al. present evidence for the demise of Acheulean technology that preceded the MSA and describe variations in late Acheulean hominin behavior that anticipate MSA characteristics. The transition to the MSA was accompanied by turnover of large mammals and large-scale landscape change. Brooks et al. establish that ～320,000 to 305,000 years ago, the populations in eastern Africa underwent a technological shift upon procurement of distantly sourced obsidian for toolmaking, indicating the early development of social exchange. Deino et al. provide the chronological underpinning for these discoveries.Deng, B., Yin, G., Li, M., Zhang, D., Lu, J., Liu, Y., Chen, J., 2018. Feature of fractures induced by hydrofracturing treatment using water and L-CO2 as fracturing fluids in laboratory experiments. Fuel 226, 35-46., the use of CO2 as a treatment fluid in the petroleum and gas industry as well as enhanced geothermal system projects has attracted the attention of many scholars. In this paper, hydrofracturing experiments were performed on shale and coal specimens employing CO2 and water as fracturing fluids, respectively. The differences of hydraulic and L-CO2 fracturing in the breakdown pressure and fracture features were investigated under different geological and engineering conditions. The experimental results indicate that preexisting flaws in reservoirs have a significant effect on the stimulation mechanism of the hydrofracturing treatment. The non-reactivation of preexisting flaws leads to tensile stimulation. In contrast, the reactivation of preexisting flaws might lead to shear stimulation under a high horizontal stress difference. The shear stimulation would impact fracture propagation, and can even induce the slip of slant fractures, that generates splay cracks at the fracture tips. Because shear slip requires a high horizontal stress difference, which reduces the conductivity of reservoirs. Comparing with hydraulic fracturing, the low viscosity of CO2 is beneficial for shear stimulation.Desvergnes, A.C., Berghe, I.V., 2018. Dyestuff identification and significance of interleaves from Moroccan manuscripts of Dalā’il al-Khayrāt. Studies in Conservation 63, 236-250. are pieces of paper which are meant to protect illuminations, illustrations, and opposite folios from pigment and ink deterioration. The Dalā’il al-Khayrāt or ‘Guidelines to the Blessings’, one of the most widespread prayer books for Muslims, was written by Muhammad ibn Sulaymān al- Jazūlī (died c.1465 CE), a Moroccan mystic Sufi. Depending on the place and date of production, from West (Morocco) to East (Southeast Asia), the manuscripts reflect local styles in the text design and the cover. From the sixteenth up to the end of the nineteenth century, some Moroccan copies were supplied with interleaves which were dyed in a colour range from pale yellow to bright fuchsia. This study comprises seven copies from collections in Qatar for which the physical features of the interleaves were studied and the dyestuffs were identified with HPLC. The analyses conducted at KIK-IRPA in Brussels have revealed that safflower was used as the main dyestuff until the industrial era, when imported synthetic dyes supplanted natural colorants. Conservation issues were also raised since early synthetic dyes found were very unstable to environmental factors. Then, the significance of these materials was explored in comparison with the silk curtains found in European medieval manuscripts.Diamond, C.W., Planavsky, N.J., Wang, C., Lyons, T.W., 2018. What the ~1.4?Ga Xiamaling Formation can and cannot tell us about the mid‐Proterozoic ocean. Geobiology 16, 219-236. a surge of recent work, the evolution of mid‐Proterozoic oceanic–atmospheric redox remains heavily debated. Constraining the dynamics of Proterozoic redox evolution is essential to determine the role, if any, that anoxia played in protracting the development of eukaryotic diversity. We present a multiproxy suite of high‐resolution geochemical measurements from a drill core capturing the ~1.4 Ga Xiamaling Formation, North China Craton. Specifically, we analyzed major and trace element concentrations, sulfur and molybdenum isotopes, and iron speciation not only to better understand the local redox conditions but also to establish how relevant our data are to understanding the contemporaneous global ocean. Our results suggest that throughout deposition of the Xiamaling Formation, the basin experienced varying degrees of isolation from the global ocean. During deposition of the lower organic‐rich shales (130–85 m depth), the basin was extremely restricted, and the reservoirs of sulfate and trace metals were drawn down almost completely. Above a depth of 85 m, shales were deposited in dominantly euxinic waters that more closely resembled a marine system and thus potentially bear signatures of coeval seawater. In the most highly enriched sample from this upper interval, the concentration of molybdenum is 51 ppm with a δ98Mo value of +1.7‰. Concentrations of Mo and other redox‐sensitive elements in our samples are consistent with a deep ocean that was largely anoxic on a global scale. Our maximum δ98Mo value, in contrast, is high compared to published mid‐Proterozoic data. This high value raises the possibility that the Earth's surface environments were transiently more oxygenated at ~1.4 Ga compared to preceding or postdating times. More broadly, this study demonstrates the importance of integrating all available data when attempting to reconstruct surface O2 dynamics based on rocks of any age. Dong, D., Shi, Z., Guang, Q., Jiang, S., Zhang, M., Zhang, C., Wang, S., Sun, S., Yu, R., Liu, D., Peng, P., Wang, S., 2018. Progress, challenges and prospects of shale gas exploration in the Wufeng–Longmaxi reservoirs in the Sichuan Basin. Natural Gas Industry 38, 67-76. Sichuan Basin is a major target for shale gas exploration in present China because of its rich gas stored in abundant black shales with multiple bed series. For further guidance or reference, field exploration and development practices in the Upper Ordovician Wufeng–Lower Silurian Longmaxi shale reservoirs were studied in terms of development stages and progress, favorable conditions for shale gas accumulation, bottlenecking issues on theories and technologies related to shale gas development, and so on. The following findings were obtained. (1) Shale with rich organic matters originated from the deep shelf has a good quality and great thickness in the continuous beds. The relatively stable wide buffer zones in synclines (anticlines) provides favorable conditions for shale gas accumulation and preservation with well-developed micro-fractures and overpressure as necessary factors for a great potential of high shale gas productivity. (2) The bottlenecking technical issues restricting the shale gas industrial development in this study area include the following aspects: understandings of rich-organic matter shale sedimentary facies and modes, shale reservoir diagenetic process and evaluation systems, shale gas generation and accumulation mechanism, geophysical logging identification and prediction of shale gas layers, low resource utilization rate, great uncertainty of shale gas development, no technological breakthrough in the exploration of shale gas reservoirs buried deeper than 3 500 m. In conclusion, this study area will be the major target for the shale gas exploration and development in China in a rather long period in the future.Donner, M.W., Bicalho, B., Sinn, C., Shotyk, W., 2018. Selenium and sulphur in Athabasca bituminous sands mineral and bitumen fractions. Fuel 224, 718-725. is increasing environmental concern regarding the emission of selenium (Se) from mining and upgrading of bitumen extracted from the Athabasca bituminous sands (ABS) in northern Alberta, Canada. However, there remains a lack of high quality analytical data for Se in this massive hydrocarbon reserve. Accurate analytical determinations of Se in bitumen from ABS are an important first step toward understanding its potential to be emitted to the environment. This has been a challenge due to the low abundance of Se combined with the preponderance of entrained mineral material (sand, clay) and the generally inadequate sensitivity of analytical methods used in the past. To overcome these issues, samples of ABS ores (McMurray Formation) underwent a toluene extraction procedure under ultra-clean lab conditions to separate bitumen from mineral particles. Separated bitumen, residual mineral material, and bulk ores were then subjected to acid-digestion and analysis using inductively coupled plasma sector-field mass spectrometry (ICP-SFMS) as well as hydride generation atomic fluorescence spectroscopy (HG-AFS). Unlike many other potentially toxic trace elements (Ag, As, Be, Cd, Cu, Pb, Sb, Tl and Zn) which exist almost exclusively in the mineral fraction, Se was found primarily (ca. 80%) in the organic (bitumen) fraction. Sulphur was determined in the same acid digests using both ICP-SFMS and inductively coupled plasma-optical emission spectroscopy (ICP-OES) and it too, was found almost exclusively in the bitumen fraction. Despite the limited number of samples available to our study, the positive, linear correlation between Se and S concentrations in bitumen suggests that S concentrations can be used as a guide to estimate their Se content. Given that Se is found mainly in the organic fraction of the ABS, there is considerable potential for mobilization of this element during upgrading and refining. The analytical methods successfully employed here have sufficient sensitivity to support studies of Se contamination of environmental media in the ABS region.dos Reis, M., 2018. Fossil-free dating. Nature Ecology & Evolution 2, 771-772. gene transfer events — the exchange of genetic material between organisms — can be used to date the timeline of evolution of microorganisms that lack a fossil record.Doyle, L.E., Marsili, E., 2018. Weak electricigens: A new avenue for bioelectrochemical research. Bioresource Technology 258, 354-364. appears to be a phylogenetically diverse trait independent of cell wall classification, with both Gram-negative and Gram-positive electricigens reported. While numerous electricigens have been observed, the majority of research focuses on a select group of highly electroactive species. Under favorable conditions, many microorganisms can be considered electroactive, either through their own mechanisms or exogenously-added mediators, producing a weak current. Such microbes should not be dismissed based on their modest electroactivity. Rather, they may be key to understanding what drives extracellular electron transfer in response to transient limitations of electron acceptor or donor, with implications for the study of pathogens and industrial bioprocesses. Due to their low electroactivity, such populations are difficult to grow in bioelectrochemical systems and characterise with electrochemistry. Here, a critical review of recent research on weak electricigens is provided, with a focus on the methodology and the overall relevance to microbial ecology and bioelectrochemical systems.Doyle, S.M., Whitaker, E.A., De Pascuale, V., Wade, T.L., Knap, A.H., Santschi, P.H., Quigg, A., Sylvan, J.B., 2018. Rapid formation of microbe-oil aggregates and changes in community composition in coastal surface water following exposure to oil and the dispersant Corexit. Frontiers in Microbiology 9, 689. doi: 10.3389/fmicb.2018.00689. the Deepwater Horizon (DWH) oil spill, massive quantities of oil were deposited on the seafloor via a large-scale marine oil-snow sedimentation and flocculent accumulation (MOSSFA) event. The role of chemical dispersants (e.g., Corexit) applied during the DWH oil spill clean-up in helping or hindering the formation of this MOSSFA event are not well-understood. Here, we present the first experiment related to the DWH oil spill to specifically investigate the relationship between microbial community structure, oil and Corexit?, and marine oil-snow in coastal surface waters. We observed the formation of micron-scale aggregates of microbial cells around droplets of oil and dispersant and found that their rate of formation was directly related to the concentration of oil within the water column. These micro-aggregates are potentially important precursors to the formation of larger marine oil-snow particles. Therefore, our observation that Corexit? significantly enhanced their formation suggests dispersant application may play a role in the development of MOSSFA events. We also observed that microbial communities in marine surface waters respond to oil and oil plus Corexit? differently and much more rapidly than previously measured, with major shifts in community composition occurring within only a few hours of experiment initiation. In the oil-amended treatments without Corexit?, this manifested as an increase in community diversity due to the outgrowth of several putative aliphatic- and aromatic-hydrocarbon degrading genera, including phytoplankton-associated taxa. In contrast, microbial community diversity was reduced in mesocosms containing chemically dispersed oil. Importantly, different consortia of hydrocarbon degrading bacteria responded to oil and chemically dispersed oil, indicating that functional redundancy in the pre-spill community likely results in hydrocarbon consumption in both undispersed and dispersed oils, but by different bacterial taxa. Taken together, these data improve our understanding of how dispersants influence the degradation and transport of oil in marine surface waters following an oil spill and provide valuable insight into the early response of complex microbial communities to oil exposure.Driskell, W.B., Payne, J.R., 2018. Macondo oil in northern Gulf of Mexico waters – Part 2: Dispersant-accelerated PAH dissolution in the Deepwater Horizon plume. Marine Pollution Bulletin 129, 412-419. the Deepwater Horizon blowout, unprecedented volumes of dispersant were applied both on the surface and at depth. Application at depth was intended to disperse the oil into smaller microdroplets that would increase biodegradation and also reduce the volumes buoyantly rising to the surface, thereby reducing surface exposures, recovery efforts, and potential stranding. In forensically examining 5300 offshore water samples for the Natural Resource Damage Assessment (NRDA) effort, profiles of deep-plume oil droplets (from filtered water samples) were compared with those also containing dispersant indicators to reveal a previously hypothesized but undocumented, accelerated dissolution of the polycyclic aromatic hydrocarbons (PAH) in the plume samples. We interpret these data in a fate-and-transport context and conclude that dispersant applications were functionally effective at depth.Drury, A.J., Lee, G.P., Gray, W.R., Lyle, M., Westerhold, T., Shevenell, A.E., John, C.M., 2018. Deciphering the state of the Late Miocene to Early Pliocene Equatorial Pacific. Paleoceanography and Paleoclimatology 33, 246-263. late Miocene‐early Pliocene was a time of global cooling and the development of modern meridional thermal gradients. Equatorial Pacific sea surface conditions potentially played an important role in this global climate transition, but their evolution is poorly understood. Here we present the first continuous late Miocene‐early Pliocene (8.0–4.4 Ma) planktic foraminiferal stable isotope records from eastern equatorial Pacific Integrated Ocean Drilling Program Site U1338, with a new astrochronology spanning 8.0–3.5 Ma. Mg/Ca analyses on surface dwelling foraminifera Trilobatus sacculifer from carefully selected samples suggest that mean sea surface temperatures (SSTs) are ~27.8 ± 1.1°C (1σ) between 6.4 and 5.5 Ma. The planktic foraminiferal δ18O record implies a 2°C cooling between 7.2 and 6.1 Ma and an up to 3°C warming between 6.1 and 4.4 Ma, consistent with observed tropical alkenone paleo‐SSTs. Diverging fine‐fraction‐to‐foraminiferal δ13C gradients likely suggest increased upwelling between 7.1–6.0 and 5.8–4.6 Ma, concurrent with the globally recognized late Miocene Biogenic Bloom. This study shows that both warm and asymmetric mean states occurred in the equatorial Pacific during the late Miocene‐early Pliocene. Between 8.0–6.5 and 5.2–4.4 Ma, low east‐west δ18O and SST gradients and generally warm conditions prevailed. However, an asymmetric mean climate state developed between 6.5 and 5.7 Ma, with larger east‐west δ18O and SST gradients and eastern equatorial Pacific cooling. The asymmetric mean state suggests stronger trade winds developed, driven by increased meridional thermal gradients associated with global cooling and declining atmospheric pCO2 concentrations. These oscillations in equatorial Pacific mean state are reinforced by Antarctic cryosphere expansion and related changes in oceanic gateways (e.g., Central American Seaway/Indonesian Throughflow restriction). Dubbelman, A.-C., Cuyckens, F., Dillen, L., Gross, G., Vreeken, R.J., Hankemeier, T., 2018. Mass spectrometric recommendations for Quan/Qual analysis using liquid-chromatography coupled to quadrupole time-of-flight mass spectrometry. Analytica Chimica Acta 1020, 62-75.: High-throughput simultaneous quantitative and qualitative (Quan/Qual) analysis is attractive to combine targeted with non-targeted analysis, e.g. in pharmacometabolomics and drug metabolism studies. This study aimed to investigate the possibilities and limitations of high-throughput Quan/Qual analysis by ultra-high performance liquid chromatography (UHPLC) coupled with high-resolution mass spectrometry (HRMS), to develop a widely applicable Quan/Qual UHPLC-HRMS method and to provide recommendations for Quan/Qual method development.Methods: A widely applicable 4.25-min UHPLC method for small-molecules was used to investigate and optimize mass spectrometric parameters of a Synapt G2S for Quan/Qual analysis. The method was applied on a rat metabolomics study investigating the effect of the fasting state and administration of a dosing vehicle on the rat plasma metabolic profile.Results: Highly important parameters for high-throughput Quan/Qual analysis were the scan mode and scan rate. A negative correlation was found between the amount of qualitative information that a method can provide and its quantitative performance (accuracy, precision, sensitivity, linear dynamic range). The optimal balance was obtained using the MSE scan mode with a short scan time of 30?ms. This 4.25-min Quan/Qual analysis method enabled quantification with accuracy and precision values?≤?20% at the lowest quality control (QC) level and ≤15% at higher QC levels for 16 out of 19 tested analytes. It provided both parent m/z values and fragmentation spectra for compound identification with limited loss of chromatographic resolution and it revealed biologically relevant metabolites in its application to the metabolomics study.Conclusion: Quan/Qual method development requires balancing between the amount of qualitative data, the quality of the quantitative data and the analysis time. Recommendations are provided for MS resolution, scan mode, scan rate, smoothing and peak integration in Quan/Qual method development and analysis.Dubicka, Z., Wierzbowski, H., Wierny, W., 2018. Oxygen and carbon isotope records of Upper Cretaceous foraminifera from Poland: vital and microhabitat effects. Palaeogeography, Palaeoclimatology, Palaeoecology 500, 33-51. and carbon isotope data of 11 Lower Campanian and 11 Upper Maastrichtian co-existing rotaliid foraminiferal taxa from Eastern Poland are presented. Pristine preservation of the studied material is documented by studies of cathodoluminescence, elemental contents and micro/nano-structures of foraminiferal tests. The variability in δ18O and δ13C values of the foraminifera is taxon-specific and relatively constant within the investigated intervals. It results from the combination of vital and microhabitat effects. A comparison of the measured isotope signatures with the published data of similar Cretaceous or modern taxa have allowed us to find benthic foraminifera which precipitated oxygen and carbon isotopes in near-equilibrium with bottom water. These are Praebulimina sp., Gyroidinoides globosus, Pullenia jarvisi, and Bolivina incrassata for oxygen, and Cibicidoides voltzianus and Cibicides beaumontianus for carbon isotopes.The observed differences between δ13C values of infaunal and epifaunal foraminiferal taxa are related to the presence of δ13CDIC (DIC - dissolved inorganic carbon) gradient in the sediment column, which was much higher in the Che?m section. Although planktic foraminifera studied are characterized by different lifestyles, this feature is not mirrored in their oxygen and carbon isotope compositions. This is probably due to effects of vital isotope fractionation and minor thermal and carbon isotope gradients in a part of the water column inhabited by these organisms. The thermal gradient between near surface and bottom waters is calculated to be ca. 4.0?°C, and ca. 7.5?°C for the Early Campanian and the Late Maastrichtian seas of East European Platform, respectively, based on the comparison of δ18O values of selected planktic and benthic foraminifera.Earl, L.A., Falconieri, V., Subramaniam, S., 2018. Microbiology catches the cryo-EM bug. Current Opinion in Microbiology 43, 199-207. the past few years, the advances in technology and methods that have revolutionized cryo-EM are allowing for key insights in a variety of areas in biology, and microbiology is no exception. A wide range of important macromolecular assemblies in prokaryotic and eukaryotic cells, as well as intact viruses, have now become accessible to investigation by new methods in 3D electron microscopy. We focus here on selected examples that illustrate this breadth, and review the application of methods in single particle cryo-EM and cryo-electron tomography to progress in the structural biology of CRISPR systems, visualization of small molecule drugs in membrane proteins, in situ visualization of bacterial nanomachines, and the analysis of antigen–antibody interactions to drive vaccine design.Eble, C.F., Greb, S.F., 2018. Geochemical, petrographic and palynologic characteristics of two late middle Pennsylvanian (Asturian) coal-to-shale sequences in the eastern Interior Basin, USA. International Journal of Coal Geology 190, 99-125. coal-to-shale sequences of late Middle Pennsylvanian (Asturian) age from the southern portion of the Eastern Interior (Illinois) Basin, USA were examined geochemically, petrographically and palynologically. The Springfield coal was found to be moderately low in ash yield and high in total sulfur content. Petrographically, the coal is high in vitrinite content and low in liptinite and inertinite. Palynologically, the bed is co-dominated by spores of arborescent lycopod and tree fern affinities. The examination of closely-spaced bench samples revealed vertical species variation within both of these plant groups. Lycospora micropapillata + L. orbicula, both of which were produced by Paralycopodites, are most abundant in basal coal benches, whereas Lycospora granulata, produced by Lepidophloios is the dominant arborescent lycopod spore throughout the rest of the bed. Thymospora pseudothiessenii is the dominant tree fern spore throughout most of the coal, with Laevigatosporites globosus becoming dominant in the top-most coal benches.The Herrin coal bed is also moderately low in ash yield and high in total sulfur content. Unlike the Springfield coal, it contains two distinct inorganic partings that have regional extent. The Herrin coal also has several coal benches with increased ash and sulfur that were not present in the Springfield coal bed. Petrographically, it is dominated by vitrinite, with the partings and high ash coal benches containing more inertinite, and liptinite. Palynologically, the Herrin coal is dominated by arborescent lycopod spores with subdominant tree fern spores. As with the Springfield coal, Lycospora micropapillata + L. orbicula are the dominant arborescent lycopod spores at the base of the coal, with Lycospora granulata dominating the rest of the bed. Granasporites medius, which was produced by Diaphorodendron and Synchysidendron, occurs more frequently in the Herrin coal bed, and are most abundant in, and in proximity to, the two inorganic partings. Tree fern spores are less abundant in the Herrin coal, and do not display any discernable vertical species variation.Collectively, both the Springfield and Herrin coal beds are interpreted to have formed in extensive planar, topogenous mires. Consistently saturated peat conditions throughout the development of both paleomires are indicated by the high vitrinite contents, and prevalence of arborescent lycopods. The deposition of widespread inorganic partings in the Herrin coal represents significant events in peat accumulation, with high ash coal benches representing smaller, more local events.Both of the coals are overlain by black, very organic-rich (avg. TOC ± 20%) marine shale. The Turner Mine Shale, which directly overlies the Springfield coal, has layers at the coal/shale contact with fairly abundant vitrinite, primarily in the form of vitrodetrinite, near the base of the shale, but the majority of the shale is dominated by the liptinite macerals bituminite, lamalginite and amorphinite. Micrinite is a major organic component of the shale. The Anna Shale, which directly overlies the Herrin coal, is similar in overall maceral composition, but contains less vitrinite, and more solid bitumen and micrinite. Trace element ratios (Ni/Co, V/Cr, V/V + Ni), indicative of paleoredox conditions, indicate that both shales were deposited under mainly dysoxic to suboxic/anoxic conditions. The shales are interpreted to represent a progressively rising water table, caused by an increase in eustatic sea levels. Vitrinite reflectance values in the shales are lower than corresponding values measured from the coal, indicating some degree of vitrinite suppression occurring in the Turner Mine and Anna Shales.Eisaman, M.D., Rivest, J.L.B., Karnitz, S.D., de Lannoy, C.-F., Jose, A., DeVaul, R.W., Hannun, K., 2018. Indirect ocean capture of atmospheric CO2: Part II. Understanding the cost of negative emissions. International Journal of Greenhouse Gas Control 70, 254-261. emissions technologies (NETs), which result in the removal of CO2 from the atmosphere, will be necessary to limit global warming to 2?°C. Unlike point-source CO2 capture, NETs are agnostic to the emission source, and reduce the existing atmospheric CO2 concentration. This enables NETs to address distributed emissions from transportation and past emissions that have led to existing atmospheric CO2 concentrations. Despite their critical necessity, there are relatively few NETs that have been developed, and existing technologies do not have sufficiently detailed techno-economic analyses to allow comparison for the purpose of strategic investment and policy decisions. An analysis was performed of the economic feasibility of a novel platform of candidate NETs – indirect ocean capture (IOC) – through industry-validated economic and chemical process modeling supported by inputs from a prototype system. This manuscript details the development of a high-fidelity estimate of the cost of avoided CO2 emissions from this NET by coupling scaled experiments to economic analyses. For the lowest-cost scenario of co-location with a desalination plant, a likely cost of $604 per metric ton of avoided CO2 (tCO2) was found, and a best-case cost of $373/tCO2. Through improvements to unit processes, creative process optimization, and reduced carbon-neutral electricity prices, the cost of IOC negative emissions may be reduced in the future. Although NETs won’t likely require deployment for several years in order to limit warming to 2?°C, an objective techno-economic assessment of the options on the table will ensure that the best technology is developed and ready when deployment is required.Eliebid, M., Mahmoud, M., Hussein, I., Elkatatny, S., Shawabkeh, R., Sultan, A., Al-Marri, M.J., 2018. Impact of surfactant on the retention of CO2 and methane in carbonate reservoirs. Energy & Fuels 32, 5355-5363. gas recovery methods such as foamed CO2 are recommended for depleted gas reservoirs. Viscoelastic surfactant (VES) is a form of a surfactant used for forming CO2 foam. In this study, the impact of VES on CH4 and CO2 retention and adsorption in calcite rock samples was studied. Crushed samples of Indiana limestone rocks of average particle size (125–250 μm) were used in the static adsorption experiments. To study the effect of VES on CH4 and CO2 adsorption, 50% of the crushed samples were conditioned in a solution of NaCl of 0.1 vol % surfactant. X-ray diffraction shows that the rock samples are 99.99% calcite and traces of quartz. The gas adsorption experiments were performed at different temperatures; namely; 50, 100, and 150 °C and at a pressure of 45 bar. At 50 °C, the plain calcite samples adsorbed more CH4 and CO2 compared to that treated with VES. However, at 100 and 150 °C, the plain sample adsorbed much less CH4 and CO2 than the treated sample. This means that at higher temperatures (100 and 150 °C) VES enhanced the adsorption of both CO2 and CH4 on the rock surface. Thermodynamic investigations showed that the process of gas adsorption in the plain samples was exothermic with ΔHads of ?13.5 and ?16.7 kJ/mol for CO2 and CH4, respectively, and at 50 °C the adsorption was spontaneous with ΔGads of ?0.425 for CH4 and ?2.599 for CO2. In contrast, at higher temperatures (100 and 150 °C), the adsorption of CO2 and CH4 on surfactant treated sample was spontaneous and endothermic with corresponding ΔHads of 36.2 and 60.1 kJ/mol and ΔGads of ?4.701 and ?0.581 for CO2 and CH4, respectively. The adsorption of CO2 was three times that of CH4 because of the high affinity of calcite to CO2. Because of the multilayer adsorption on both samples, Freundlich isotherm was found to be the best model that fits the experimental data of calcite with both CO2 and CH4 at different temperatures. Dynamic adsorption experiments were carried out using gas coreflooding system with the same calcite cores used in the static adsorption experiments. The results of this study showed that carbonate rock samples conditioned in the surfactant solution have great adsorption potential for CO2 and are excellent candidates for CO2 sequestration. However, surfactant promoted high CH4 adsorption at 100 and 150 °C, and this will reduce the natural gas recovery. In contrast, using viscoelastic surfactant at low-temperature reservoirs (50 °C) reduced CH4 adsorption by blocking the active adsorption sites in the carbonate rock samples, and this will increase the gas recovery.Eruteya, O.E., Reshef, M., Ben-Avraham, Z., Waldmann, N., 2018. Gas escape along the Palmachim disturbance in the Levant Basin, offshore Israel. Marine and Petroleum Geology 92, 868-879. seismic reflection and bathymetry data are analyzed to investigate the subsurface configurations promoting fluid escape along the Palmachim disturbance; a 20?km?×?10?km gravitational collapse structure, offshore southern Israel. The dataset reveals seabed pockmarks with diameters ranging between 200 and 500?m, and depth of <50?m. A significant number of the pockmarks are located along ridge-like structures associated with compression, while an outlier is proximal to a turbidite channel. Seismic attribute analyses reveal a series of fluid-related amplitude anomalies within Quaternary sediments. We propose the onset of subsurface fluid flow to be synchronous with the evolution of the Palmachim disturbance, which was likely triggered by local seismicity. Our results suggest fluids from pre-Messinian strata exploited deformational pathways in the overburden to reach shallower levels where they were sequestered and redistributed in transient reservoirs (mass-transport complexes and channel-levee complex). The fluids are either focused toward the seafloor for expulsion or migrating into the ridges, providing four-way closure and accommodation. However, the fluids may also have no (pre)Messinian component, being locally sourced biogenic methane within the channel-levee complex. Under both scenarios, elevated pore-pressure resulted in hydrofracturing of the seafloor sediment and expulsion of fluids creating the pockmarks. The discovery of enhanced fluid escape through the Palmachim disturbance represents a new source of global methane not previously accounted for in carbon budgets from this region of the Mediterranean Sea.Espinoza, D.N., Jung, H., Major, J.R., Sun, Z., Ramos, M.J., Eichhubl, P., Balhoff, M.T., Choens, R.C., Dewers, T.A., 2018. CO2 charged brines changed rock strength and stiffness at Crystal Geyser, Utah: Implications for leaking subsurface CO2 storage reservoirs. International Journal of Greenhouse Gas Control 73, 16-28. geological storage in saline aquifers results in acidification of resident brine. Chemical reactions between acidified brine and rock minerals lead to dissolution and precipitation of minerals at various time scales. Mineral dissolution and precipitation are often neglected in assessing the mechanical integrity of target storage formations, yet, changes in rock strength and deformational behavior can impact trapping mechanisms. This study shows the impact of exposure to CO2-charged brine on shear strength and stiffness of various outcrop rocks evaluated through triaxial testing. The tested rocks were exposed to CO2-charged brine over geological time at a naturally occurring near-surface seepage along the Little Grand Wash Fault and Salt Wash Grabens, which include the Crystal Geyser site near the town of Green River, Utah. Prior work suggests that this site provides a near-surface structural analog for possible fault-controlled CO2 leakage over time scales that exceed expected injection time scales (10–100 years). Results show mechanical alteration in various aspects: (1) CO2-charged brine alteration at near-surface conditions results in mineral dissolution/precipitation and reduction of shear strength and brittleness of Entrada sandstone and Summerville siltstone samples, and (2) carbonate precipitation in fractured Mancos shale leads to matrix stiffening and fracture mineralization resulting in overall stiffer and likely tighter shale. Additional discrete element simulations coupled with a bonded-particle-model confirm the role of cement bond size alteration as one of the main controls for rock chemo-mechanical alteration in sandstones. The chemo-mechanical alteration path that mimics cement dissolution (under stressed subsurface conditions) results in vertical compaction and lateral stress relaxation. Overall, results show that rock exposure to CO2-charged brine can impart distinct petrophysical and geomechanical changes according to rock lithology and location with respect to major CO2 conduits. While mineral dissolution in the storage rock may result in undesired reservoir strains and changes of stresses, mineral precipitation downstream from a leakage path can help seal potentially induced fractures.Esquinas, N., Márquez, G., Permanyer, A., Gallego, J.R., 2018. Geochemical evaluation of crude oils from the Caracara and Tiple areas, eastern Llanos Basin, Colombia: Palaeo biodegradation and oil mixing. Journal of Petroleum Geology 41, 113-134. study presents an organic geochemical characterization of heavy and liquid oils from Cretaceous and Cenozoic reservoir rocks in the Tiple and Caracara blocks in the eastern Llanos Basin, Colombia. Samples of heavy oil were recovered from the Upper Eocene Mirador Formation and the C7 interval of the Oligocene – Miocene Carbonera Formation; the liquid oils came from these intervals and from the Cretaceous Guadalupe, Une and Gachetá Formations. The heavy oil and most of the liquid oils probably originated from multiple source rocks or source facies, and showed evidence of biodegradation as suggested by the coexistence of n‐alkanes and 25‐norhopanes. The results indicate a close genetic relationship between the samples in the Carbonera (C7 interval), Mirador and Guadalupe Formation reservoirs. These petroleums are interpreted to result from at least two separate oil charges. An early charge (Oligocene to Early Miocene) was derived from marine carbonate and transitional siliciclastic Cretaceous source rocks as indicated by biomarker analysis using GC/MS. This initial oil charge was biodegraded in the reservoir, and was mixed with a later charge (or charges) of fresh oil during the Late Miocene to Pliocene. A relatively high proportion of the unaltered oil charge was recorded for heavy oil samples from the Melero‐1 well in the Tiple block, and is inferred to originate from Cenozoic carbonaceous shale or coaly source rocks. Geochemical parameters suggest that oils from the Gachetá and Une Formations are similar and that they originated from a source different to that of the other oil samples. These two oils do not correlate well with extracts from transitional siliciclastic source rock from the Upper Cretaceous Gachetá Formation in the Ramiriqui‐1 well, located in the LLA 22 block to the north. By contrast, one or more organofacies of the Gachetá Formation may have generated the heavy oil and most of the liquid oil samples. The results suggest that the heavy oils may have formed as a result of biodegradation at the palaeo oil‐water contact, although deasphalting cannot entirely be dismissed.Evangelista, R.F., Vargas, F.M., 2018. Prediction of the temperature dependence of densities and vapor pressures of nonpolar hydrocarbons based on their molecular structure and refractive index data at 20?°C. Fluid Phase Equilibria 468, 29-37. a previous publication, a one-parameter equation based on the perturbed chain version of the statistical associating fluid theory, assisted by a group contribution method (1P-PC-SAFT) was proposed for cases where limited experimental data are available (Evangelista and Vargas, Ind. Eng. Chem. Res., 2017). The method was proven to be robust when a single vapor pressure data point was used for the PC-SAFT parameter tuning. Motivated by this fact, a methodology for estimating a saturation data point from refractive index and molecular weight was developed in this work. The proposed correlations also represent an alternative method for calculating critical properties and acentric factor for non-polar hydrocarbons as a function of their molecular weight and refractive index. These alternative correlations to find critical properties can be readily applied to cubic equations of state or methods based on the principle of the corresponding states. The predictive capability of the proposed methodology was assessed over a wide range of temperatures and pressures. Average absolute deviations of 8.24% in vapor pressure and 2.04% in saturated liquid density were obtained for ten representative compounds consisted of aliphatic, aromatics, and cyclic nonpolar hydrocarbons. The results obtained in this work confirm that with the proposed methodology it is possible to relate molecular structure and refractive index of liquid nonpolar hydrocarbons at 20?°C to their density and vapor pressure at high temperatures.Fan, J., Sappington, E.N., Rifai, H.S., Rodrigues, D.F., 2018. Confocal microscopy as a new real-time quantification method for oil content in produced water. Journal of Petroleum Science and Engineering 167, 54-63. research proposes confocal laser fluorescence microscopy (CLFM) as an enabling technology to quantify oil prior to produced water disposal. This method takes advantage of the self-fluorescing properties of oil to visualize and quantify in 3D oil droplets in water in real-time. This investigation initially involves the identification and optimization of parameters affecting CLFM oil measurements in synthetically prepared produced water, followed by validation of the optimum CLFM parameters for oil quantification in real produced water. This study demonstrated that the optimized excitation wavelength, z-step size, image analysis threshold value, and minimum sampling size parameters for the CLFM method are suitable for different types of oil. The optimum amount of time for analysis, however, changed for oils with different densities due to different oil upward movement velocities. The detection range of the CLFM was determined to be between 1 and 250?ppm. The quantification of oil content in three different produced water samples were also investigated with the CLFM method and results were compared with the standard EPA 1664 method. The results for both methods correlated well, which suggests that the CLFM has potential to be used as an initial real-time screening of the oil quantities of treated produced water prior to environmental releases in water streams. This technique has several advantages over other methods, such as does not require hazardous solvents for oil extraction, is less labor intensive, and can be automated for real-time online applications, such as subsea systems.Fanti, L., Drieu, L., Mazuy, A., Blasco, T., Lugliè, C., Regert, M., 2018. The role of pottery in Middle Neolithic societies of western Mediterranean (Sardinia, Italy, 4500-4000?cal BC) revealed through an integrated morphometric, use-wear, biomolecular and isotopic approach. Journal of Archaeological Science 93, 110-128. use of pottery in the Early Neolithic communities of Western Mediterranean has begun to be addressed by recent studies concerning the residues of dietary commodities in potsherds. In order to contribute to a broader perspective on the issue of pottery function, we investigate pottery assemblages through an integrated methodology, combining the study of vessel morphology and morphometry, use-wear analysis, biomolecular and compound-specific carbon isotopic analysis of residues. We focus on the use of pottery containers by advanced Middle Neolithic societies of Sardinia (Italy, 4500-4000?cal BC), protagonists of significant technical, economic and cultural changes in the completion of Neolithisation in this island. The aims are to elucidate the role of whole pottery assemblages in technical and socioeconomic systems of Middle Neolithic communities and to provide data on the exploitation of animal and plant resources during this phase.Based on the integrated combination of data, six categories of vessel use are identified. The results reveal a differential integration of vessels in activities related to the exploitation of distinct kinds of resources (ruminant adipose/dairy fats and plant foods vs. non-ruminant and aquatic products) and highlight specific behaviours of Middle Neolithic societies in selecting pottery morphotypes for different uses, notably in processing products with heating.Fei, Y., Marshall, M., Jackson, W.R., Qi, Y., Auxilio, A.R., Chaffee, A.L., Gorbaty, M.L., Daub, G.J., Cassidy, P.J., 2018. Long-time-period, low-temperature reactions of Green River Oil Shale. Energy & Fuels 32, 4808-4822. of water-washed chunks of a deeply buried Green River oil shale (2880–2920 ft, well below the water table) have been carried out in N2–H2O and CO–H2O for up to 28 days at temperatures in the range of 280–370 °C. Large variations in yields of liquid products were observed for reactions below 330–340 °C. These were attributed to varying mineralogy in the chunks because the variations disappeared for reactions of ground samples or reactions above 330–340 °C, at which point the chunks disintegrated. Liquid-product yields of up to 70 wt % dry mineral matter free could be obtained from the chunks at temperatures as low as 320 °C, provided that long reaction times of 14 or 28 days were used. In particular, at lower temperatures, yields were higher under N2 than under CO, but the quality of the CO–H2O petroleum or oil/gas products tended to be better than that of N2–H2O products. The liquid products contained 1–2 wt % nitrogen, were high in aliphatic material, and contained significant amounts of heavily substituted aromatic rings.Fernández‐Cabezón, L., Galán, B., García José, L., 2018. Unravelling a new catabolic pathway of C‐19 steroids in Mycobacterium smegmatis. Environmental Microbiology 20, 1815-1827. this work, we have characterized the C‐19+ gene cluster (MSMEG_2851 to MSMEG_2901) of Mycobacterium smegmatis. By in silico analysis, we have identified the genes encoding enzymes involved in the modification of the A/B steroid rings during the catabolism of C‐19 steroids in certain M. smegmatis mutants mapped in the PadR‐like regulator (MSMEG_2868), that constitutively express the C‐19+ gene cluster. By using gene complementation assays, resting‐cell biotransformations and deletion mutants, we have characterized the most critical genes of the cluster, that is, kstD2, kstD3, kshA2, kshB2, hsaA2, hsaC2 and hsaD2. These results have allowed us to propose a new catabolic route named C‐19+ pathway for the mineralization of C‐19 steroids in M. smegmatis. Our data suggest that the deletion of the C‐19+ gene cluster may be useful to engineer more robust and efficient M. smegmatis strains to produce C‐19 steroids from sterols. Moreover, the new KshA2, KshB2, KstD2 and KstD3 isoenzymes may be useful to design new microbial cell factories for the 9α‐hydroxylation and/or Δ1‐dehydrogenation of 3‐ketosteroids. Fernández‐Remolar, D.C., Harir, M., Carrizo, D., Schmitt‐Kopplin, P., Amils, R., 2018. Productivity contribution of Paleozoic woodlands to the formation of shale‐hosted massive sulfide deposits in the Iberian Pyrite Belt (Tharsis, Spain). Journal of Geophysical Research: Biogeosciences 123, 1017-1040. geological materials produced during catastrophic and destructive events are an essential source of paleobiological knowledge. The paleobiological information recorded by such events can be rich in information on the size, diversity, and structure of paleocommunities. In this regard, the geobiological study of late Devonian organic matter sampled in Tharsis (Iberian Pyrite Belt) provided some new insights into a Paleozoic woodland community, which was recorded as massive sulfides and black shale deposits affected by a catastrophic event. Sample analysis using TOF-SIMS (Time of Flight Secondary Ion Mass Spectrometer), and complemented by GC/MS (Gas Chromatrograph/Mass Spectrometer) identified organic compounds showing a very distinct distribution in the rock. While phytochemical compounds occur homogeneously in the sample matrix that is composed of black shale, the microbial-derived organics are more abundant in the sulfide nodules. The cooccurrence of sulfur bacteria compounds and the overwhelming presence of phytochemicals provide support for the hypothesis that the formation of the massive sulfides resulted from a high rate of vegetal debris production and its oxidation through sulfate reduction under suboxic to anoxic conditions. A continuous supply of iron from hydrothermal activity coupled with microbial activity was strictly necessary to produce this massive orebody. A rough estimate of the woodland biomass was made possible by accounting for the microbial sulfur production activity recorded in the metallic sulfide. As a result, the biomass size of the late Devonian woodland community was comparable to modern woodlands like the Amazon or Congo rainforests.Ferreira, F.A.V., Barbalho, T.C.S., Araújo, I.R.S., Oliveira, H.N.M., Chiavone-Filho, O., 2018. Characterization, pressure–volume–temperature properties, and phase behavior of a condensate gas and crude oil. Energy & Fuels 32, 5643-5649. oil reservoirs are underground and have the oil and gas contained in the porous rock at high temperatures and pressures. Only 5–20% of the oil is withdrawn in primary production. Further recovery can be achieved by injecting carbon dioxide (CO2) that displaces and dissolves part of the remaining oil; this process is called enhanced oil recovery. Although the characterization and fractionation of petroleum are well-known and studied, each oil sample represents a unique multicomponent system; therefore, an individual study of the sample is required. Real samples of condensate gas (CG) and light crude oil (LCO) were collected and analyzed for density, viscosity, atmospheric distillation and fractionation, and aiming characterization. Synthetic visual and non-visual methods for high pressure were successfully applied for bubble point measurements of the systems composed of supercritical CO2 and CG or LCO. Phase envelope calculations were developed on the basis of pseudo-components obtained by atmospheric distillation and density values using the Adachi–Lu–Sugie equation of state with van der Waals mixing rule with one interaction parameter (kij) from the literature. Pressure–volume–temperature (PVT) measurements are reported for the systems CG + CO2 and LCO + CO2 as a function of the temperature and pressure and in a wide range of CO2 composition. Crude oil characterization using atmospheric distillation and density measurements was demonstrated to be feasible with accuracy, because the boiling points and specific mass obtained allowed us to propose a series of pseudo-components to represent the sample phase behavior studied experimentally. Thus, results suggest that the characterization and fractioning of the samples were effective. Thermodynamic modeling and experimental data presented an average deviation of 3.1% to CG + CO2 and 2.5% to LCO + CO2 systems, indicating reasonable accuracy for petroleum samples.Fianu, J., Gholinezhad, J., Hassan, M., 2018. Comparison of temperature-dependent gas adsorption models and their application to shale gas reservoirs. Energy & Fuels 32, 4763-4771. quantities of gas are adsorbed onto the rock matrix in shale gas reservoirs. Accounting for this adsorbed gas in reservoir calculations is key for realistic estimations of gas in place and overall gas production, and later as a target for enhanced gas recovery methods like thermal stimulation. The classical Langmuir isotherm fails to represent gas adsorption at multiple temperatures, thereby making its application in thermal stimulation strategies limited. In this work, several temperature-dependent gas adsorption models were reviewed and grouped further into both temperature-dependent and -independent Langmuir volume. Application of the models to several shale gas data sets obtained from different regions shows minimal differences in the successful prediction of gas adsorption using either the temperature-dependent or -independent Langmuir volume models. However, caution is to be exercised in the choice of models for use in numerical simulation studies when extrapolating to temperatures that might be outside laboratory conditions and for which no data exist. For such cases, use of the models might result in an under- or over-estimation of the volume of adsorbed gas.Fimmel, E., Michel, C.J., Starman, M., Strüngmann, L., 2018. Self-complementary circular codes in coding theory. Theory in Biosciences 137, 51-65. circular codes are involved in pairing genetic processes. A maximal $$C^3$$ C 3 self-complementary circular code X of trinucleotides was identified in genes of bacteria, archaea, eukaryotes, plasmids and viruses (Michel in Life 7(20):1–16 2017, J Theor Biol 380:156–177, 2015; Arquès and Michel in J Theor Biol 182:45–58 1996). In this paper, self-complementary circular codes are investigated using the graph theory approach recently formulated in Fimmel et?al. (Philos Trans R Soc A 374:20150058, 2016). A directed graph $$\mathcal {G}(X)$$ G ( X ) associated with any code X mirrors the properties of the code. In the present paper, we demonstrate a necessary condition for the self-complementarity of an arbitrary code X in terms of the graph theory. The same condition has been proven to be sufficient for codes which are circular and of large size $$\mid X \mid \ge 18$$ ∣ X ∣ ≥ 18 trinucleotides, in particular for maximal circular codes ( $$\mid X \mid = 20$$ ∣ X ∣ = 20 trinucleotides). For codes of small-size $$\mid X \mid \le 16$$ ∣ X ∣ ≤ 16 trinucleotides, some very rare counterexamples have been constructed. Furthermore, the length and the structure of the longest paths in the graphs associated with the self-complementary circular codes are investigated. It has been proven that the longest paths in such graphs determine the reading frame for the self-complementary circular codes. By applying this result, the reading frame in any arbitrary sequence of trinucleotides is retrieved after at most 15 nucleotides, i.e., 5 consecutive trinucleotides, from the circular code X identified in genes. Thus, an X motif of a length of at least 15 nucleotides in an arbitrary sequence of trinucleotides (not necessarily all of them belonging to X) uniquely defines the reading (correct) frame, an important criterion for analyzing the X motifs in genes in the future.Fleeger, J.W., Riggio, M.R., Mendelssohn, I.A., Lin, Q., Hou, A., Deis, D.R., 2018. Recovery of saltmarsh meiofauna six years after the Deepwater Horizon oil spill. Journal of Experimental Marine Biology and Ecology 502, 182-190. examined the recovery of infauna from the 2010 Deepwater Horizon oil spill in reference, moderately and heavily oiled Louisiana, USA salt marshes. Although density and diversity were severely impacted by the spill initially, total meiofauna, nematodes, copepods, and annelids, excluding the polychaete Manayunkia aestuarina, recovered in about 3 years in near synchrony with Spartina alterniflora stem density. However other common taxa either recovered more slowly (i.e., juvenile bivalves and amphipods) or remained significantly lower in density at oiled compared to reference sites 6 years after the spill. Specifically, M. aestuarina, the tanaid Hargeria rapax, the kinorhynch Echinoderes coulli, ostracods, and juvenile gastropods did not recover at the heavily oiled sites, and M. aestuarina and E. coulli failed to recover at moderately oiled sites. Several factors possibly contributed to slow recovery even after the re-establishment of aboveground vegetation. The concentration of petroleum hydrocarbons (TPH) remained elevated at moderately and heavily oil sites, and the direct toxic effects of oil may have been long lasting for intolerant fauna; the densities of E. coulli and M. aestuarina across all samples were inversely correlated with TPH. In addition, several of the slowly recovering taxa also disperse slowly. Finally, live belowground biomass of roots and rhizomes (a key indicator of sediment quality) remained significantly reduced at heavily and moderately oiled sites, and belowground biomass and the densities of M. aestuarina and juvenile gastropods were positively correlated. We conclude that the factors controlling the rate and intensity of infaunal recovery from the DHOS differed among taxa and over time. The factors that were important later in the recovery process were not dissimilar to those affecting succession following marsh restoration by planting S. alterniflora, and the legacy of oiling from the spill did not greatly slow the recovery of infauna compared to that observed in restored wetlands. At current rates, full recovery of the infaunal community will require about a decade at moderately oiled and longer at heavily oiled sites.Fleming, E.J., Woyke, T., Donatello, R.A., Kuypers, M.M.M., Sczyrba, A., Littmann, S., Emerson, D., 2018. Insights into the fundamental physiology of the uncultured Fe-oxidizing bacterium Leptothrix ochracea. Applied and Environmental Microbiology 84, Article e02239-17.: Leptothrix ochracea is known for producing large volumes of iron oxyhydroxide sheaths that alter wetland biogeochemistry. For over a century, these delicate structures have fascinated microbiologists and geoscientists. Because L. ochracea still resists long-term in vitro culture, the debate regarding its metabolic classification dates back to 1885. We developed a novel culturing technique for L. ochracea using in situ natural waters and coupled this with single-cell genomics and nanoscale secondary-ion mass spectrophotometry (nanoSIMS) to probe L. ochracea's physiology. In microslide cultures L. ochracea doubled every 5.7 h and had an absolute growth requirement for ferrous iron, the genomic capacity for iron oxidation, and a branched electron transport chain with cytochromes putatively involved in lithotrophic iron oxidation. Additionally, its genome encoded several electron transport chain proteins, including a molybdopterin alternative complex III (ACIII), a cytochrome bd oxidase reductase, and several terminal oxidase genes. L. ochracea contained two key autotrophic proteins in the Calvin-Benson-Bassham cycle, a form II ribulose bisphosphate carboxylase, and a phosphoribulose kinase. L. ochracea also assimilated bicarbonate, although calculations suggest that bicarbonate assimilation is a small fraction of its total carbon assimilation. Finally, L. ochracea's fundamental physiology is a hybrid of those of the chemolithotrophic Gallionella-type iron-oxidizing bacteria and the sheathed, heterotrophic filamentous metal-oxidizing bacteria of the Leptothrix-Sphaerotilus genera. This allows L. ochracea to inhabit a unique niche within the neutrophilic iron seeps. Importance: Leptothrix ochracea was one of three groups of organisms that Sergei Winogradsky used in the 1880s to develop his hypothesis on chemolithotrophy. L. ochracea continues to resist cultivation and appears to have an absolute requirement for organic-rich waters, suggesting that its true physiology remains unknown. Further, L. ochracea is an ecological engineer; a few L. ochracea cells can generate prodigious volumes of iron oxyhydroxides, changing the ecosystem's geochemistry and ecology. Therefore, to determine L. ochracea's basic physiology, we employed new single-cell techniques to demonstrate that L. ochracea oxidizes iron to generate energy and, despite having predicted genes for autotrophic growth, assimilates a fraction of the total CO2 that autotrophs do. Although not a true chemolithoautotroph, L. ochracea's physiological strategy allows it to be flexible and to extensively colonize iron-rich wetlands. Florentin, L., Deloule, E., Faure, F., Mangin, D., 2018. Chemical 3D-imaging of glass inclusions from Allende (CV3) olivine via SIMS: A new insight on chondrule formation conditions. Geochimica et Cosmochimica Acta 230, 83-93. glass inclusions - hosted in Mg-rich olivines from Allende (CV3) type I chondrules - and synthetic melt inclusions - trapped in forsterite crystallized from CMAS (CaO-MgO-Al2O3-SiO2) melts - were mapped by Secondary Ion Mass Spectrometry (SIMS) for CMAS major oxides. The first ever 3D chemical images of extra-terrestrial glass inclusions were obtained, along with chemical depth profiles for each oxide. Results show similar patterns for both synthetic glass inclusions (trapped in olivine formed by slow crystallization in a magmatic liquid) and natural inclusions from Allende's olivines. No incompatible-rich boundary layer or diffusion pattern was observed in either case. The absence of an incompatible-rich boundary layer suggests that the olivine overgrowth surrounding glass inclusions in Allende's olivines was formed during slow cooling of the host olivine and likely the surrounding chondrule. This provides new constraints on the cooling rates of type I chondrules.Fonseca, C., Mendon?a Filho, J.G., Lézin, C., Duarte, L.V., Fauré, P., 2018. Organic facies variability during the Toarcian Oceanic Anoxic Event record of the Grands Causses and Quercy basins (southern France). International Journal of Coal Geology 190, 218-235. early Toarcian is marked worldwide by major environmental changes that resulted in organic-rich black shale deposition, the Toarcian Oceanic Anoxic Event (T-OAE). This organic-rich sedimentation is particularly recorded in the Grands Causses (GCB) and Quercy (QB) basins. The main objectives of this study are the characterization, through organic petrology and geochemistry techniques, of the organic matter (OM) of the late Pliensbachian – early Toarcian sedimentary successions of these basins and the definition of the organic facies, assessing their implications in the evolution of depositional paleoenvironments. In the GCB sedimentation occurred, during the late Pliensbachian, in a well oxygenated water body (Total Organic Carbon - TOC 0.6wt.% and low Amorphous Organic Matter - AOM) proximal to the terrestrial source area (high terrestrial contribution) with marine influence. In the lattermost Pliensbachian a shallowing of the water column is observed with decrease of marine influence and separation from the terrestrial source area (TOC 0.9wt.%, AOM and zooclasts co-dominate) under an arid climate (Classopollis ssp.). From the Tenuicostatum to early Serpentinum chronozones a restricted and stagnated environment (TOC 5.7wt.%, AOM dominates) is implemented. From middle to late Serpentinum Chronozone the reestablishment of the oxygen levels (decrease in TOC and AOM) takes place, as well as paleoceanographic circulation patterns. In the QB, the late Pliensbachian to earliest Toarcian is characterized by low TOC (0.2wt.%) with sedimentation occurring in a shallow oxygenated proximal water body (amorphous Hydrozoans dominate) separated from the terrestrial source area with arid climate (Classopollis ssp.), and with episodes of emersion. From the Semicelatum Subchronozone to Serpentinum Chronozone the development of dysoxic to anoxic conditions (TOC 4.2wt.%) takes place, associated with water column stratification and more effective non-carbonate sedimentation, and with an increase in water level. For the lattermost Serpentinum Chronozone shallowing of a more oxidizing water body, with some oxygen depletion still present is proposed. The differences in these paleoenvironmental depositional contexts further demonstrate that, although the T-OAE has a global character, local control mechanisms in these basins play a pivotal role. Furthermore, the first occurrence of Hydrozoans, namely its free-swimming medusoid forms, is described in organopalynological preparations of sediments from the Pliensbachian–Toarcian and their first paleoenvironmental application in a palynofacies based study is made.Frederick, M., Gallup Jr., G.G., 2017. The demise of dinosaurs and learned taste aversions: The biotic revenge hypothesis. Ideas in Ecology and Evolution 10, 47-54. hypotheses have been advanced to explain the worldwide extinction event that led to the disappearance of the dinosaurs. There is considerable empirical support for the well-known asteroid impact hypothesis, and volcanic eruptions in the Deccan Traps have also been implicated. Increasingly, theories involving multiple causes are being considered, yet few of these consider how the cognitive and behavioral abilities of certain classes of animals may have differed in ways that allowed some to survive while others perished. Here we advance the hypothesis along with supporting evidence that the emergence of toxic plants coupled with an inability to form learned taste aversions may have contributed to the extinction of dinosaurs.Frei, R., Paulukat, C., Bruggmann, S., Klaebe, R.M., 2018. A systematic look at chromium isotopes in modern shells – implications for paleo-environmental reconstructions. Biogeosciences Discussions 2018, 1-48. chromium isotope system (53Cr?/?52Cr expressed as δ53Cr relative to NIST SRM 979) in marine biogenic and non-biogenic carbonates is currently being evaluated as a proxy for the redox state of the ocean. Previous work has concentrated on using corals and foraminifera for this purpose, but investigations focusing on the behavior of Cr in bivalves as potential archives are lacking. Due to their often good preservation, fossil marine biogenic carbonates have the potential to serve as useful archives for the reconstruction of past ocean redox fluctuations and eventually link those to climatic changes throughout Earth’s history. Here, we present an evaluation of the Cr isotope system in shells of some modern bivalves. Shell species from Lucidinadae, Cardiidae, Glycimerididae, and Pectenidae, collected systematically from one Mediterranean location (Playa Poniente, Benidorm, Spain) over a three year period, reveal δ53Cr values ranging from 0.15 to 0.65?‰, values that are systematically below the local seawater δ53Cr value of 0.83?±?0.05?‰. This attests for significant reduction of dissolved seawater chromium in the process leading to calcification and thus for control of Cr isotope fractionation during biological routes. A similar, constant offset in δ53Cr values relative to surface seawater is observed in shells from Mytilius edulis from an arctic location (Godhavn, Disko Bay, Greenland). Chromium concentrations in the studied shells are significantly controlled by organic matter and typically range from 0.020 to 0.100?ppm, with some higher concentrations of up to 0.163?ppm recorded in Pectenidae. We also observe subtle, species-dependent differences in average Cr isotope signatures in the samples from Playa Poniente, particularly of Lucidinadae and Cardiidae, with considerably depressed and elevated δ53Cr values, respectively, relative to the other species investigated. Within-species heterogeneities, both in Cr concentrations and δ53Cr values, are favorably seen to result from vital effects during shell calcification rather than from heterogeneous seawater composition. This is because we observe that the surface seawater composition in the particular Playa Poniente location remained constant during July month of the three years we collected bivalve samples. Within single shell heterogeneities associated with growth zones reflecting one to several years of growth, both in δ53Cr and Cr concentrations, are observed in a sample of Placuna placenta and Mimachlamys townsendi. We suspect that these variations are, at least partially, related to seasonal changes in δ53Cr of surface seawaters. Recognizing the importance of organic substances in the bivalve shells, we propose a model whereby reduction of Cr(VI) originally contained in the seawater as chromate ion and transported to the calcifying space, to Cr(III), is effectively adsorbed onto organic macromolecules which eventually get included in the growing shell carbonates. This study, with its definition of statistically sound offsets in δ53Cr values of certain bivalve species from ambient seawater, forms a base for futures investigations aimed at using fossil shells as archives for the reconstruction of paleo-seawater redox fluctuations.Fu, W., Xu, M., Sun, K., Hu, L., Cao, W., Dai, C., Jia, Y., 2018. Biodegradation of phenanthrene by endophytic fungus Phomopsis liquidambari in?vitro and in?vivo. Chemosphere 203, 160-169., as a widespread polycyclic aromatic hydrocarbons (PAHs) contaminant in vitro and in vivo of plant, has the characteristics of carcinogenicity, teratogenicity and mutagenicity. This work aimed to explore the phenanthrene metabolic mechanism by Phomopsis liquidambari in vitro, as well as the bioremediation ability through P. liquidambari-rice combination. This strain was able to use phenanthrene as source of carbon and energy to grow, more than 77% of added 50?mg?L?1 phenanthrene was removed after 10?d in MSM. We identified the metabolic products via HPLC-MS and proposed two possible degradation pathways. Phenanthrene was firstly combined with oxygen to become phenanthrene 9,10-oxide, and then degraded to 9-phenanthrol, followed by oxidization to 9,10-dihydroxyphenanthrene. In addition, that epoxide (phenanthrene 9,10-oxide) was also hydrolyzed to phenanthrene trans-9,10-dihydrodiol, and then dehydrogenized to 9,10-dihydroxyphenanthrene, which was further degraded to 9,10-phenanthrenequinone; during this metabolic pathway, the changes of P450 monooxygenase, epoxide hydrolase, dehydrogenase and catechol 2,3-dioxygenase activities and their corresponding gene transcription levels were closely related. What's more, P. liquidambari could combine with rice to eliminate phenanthrene accumulated in vivo of rice seedlings, and the removal rate in inoculation treatment represented a significant difference (increased 25.68%) compared with uninoculation treatment after cultivation 30?d. Therefore, we concluded that P. liquidambari could not only respond to phenanthrene pollution stress in vitro but also exert a mitigation effect on plants accumulated phenanthrene. This work provides a foundation for applying endophytic fungi to PAHs bioremediation in vitro and in vivo.Gafni, A., Lihl, C., Gelman, F., Elsner, M., Bernstein, A., 2018. δ13C and δ37Cl isotope fractionation to characterize aerobic vs anaerobic degradation of trichloroethylene. Environmental Science & Technology Letters 5, 202–208. (TCE) is a carcinogenic organic chemical impacting water resources worldwide. Its breakdown by reductive vs oxidative degradation involves different types of chemical bonds. Hence, if distinct isotope effects are reflected in dual element (carbon and chlorine) isotope values, such trends could help distinguishing both processes in the environment. This work explored dual element isotope trends associated with TCE oxidation by two pure bacterial cultures: Pseudomonas putida F1 and Methylosinus trichosporium OB3b, where the latter expresses either soluble methane-monooxygenase (sMMO) or particulate methane-monooxygenase (pMMO). Carbon and chlorine isotope enrichment factors of TCE (ε13C = ?11.5, ?2.4, and ?4.2‰; ε37Cl = 0.3, ?1.3, and ?2.4‰, respectively) differed strongly between the strains. The dual element isotope trend for strain F1 (ε13C/ε37Cl = ?38) reflected, as expected, primary carbon and negligible chlorine isotope effects, whereas unexpectedly large chlorine isotope effects became apparent in the trend obtained with strain OB3b (ε13C/ε37Cl = +1.7 for sMMO and pMMO). Therefore, although dual element isotope analysis partly reflects predicted differences in oxidative vs reductive (ε13C/ε37Cl = 3.4–5.7) degradation, the unexpected OB3b fractionation data may challenge field interpretation.Gai, Q., Liu, C., Zhao, S., Dong, H., Zhao, X., 2018. Separation and identification of Fischer-Tropsch wax by high temperature gas chromatography-mass spectrometry. Chinese Journal of Chromatography 36, 303-308. (FT) wax is an important material produced from FT synthesis reactions. In this study, an improved separation and identification method for FT wax by high temperature gas chromatography (HTGC) coupled with cold-on-column (without pretreatment) was developed. In our improved separation procedure, the carrier gas was changed to helium and a long chromatographic column was adapted for use at high temperature. The n-alkanes in FT wax were well separated from other unknown components and the heavy components with carbon numbers higher than C90 could be eluted. Unknown components of the FT wax fraction were confirmed as alkanes, alkenes and oxygenated compounds by using HTGC-mass spectrometry. These results improve our understanding of the FT synthesis process and increase our detailed knowledge of FT products.Galey, M.M., Sanchez, L.M., 2018. Spatial analyses of specialized metabolites: The key to studying function in hosts. mSystems 3, DOI: 10.1128/mSystems.00148-17. communities contribute to a wide variety of biological functions in hosts and have the ability to specifically influence the health of those organisms through production of specialized metabolites. However, the structures or molecular mechanisms related to health or disease in host-microbe interactions represent a knowledge gap. In order to close this gap, we propose that a combinatory approach, pulling from microbiology and analytical chemistry, be considered to investigate these interactions so as to gain a better understanding of the chemistry being produced. We hypothesize that bacteria alter their chemistry in order to survive and induce specific states in their host organisms. Our lab makes use of imaging mass spectrometry and other analytical techniques to study this chemistry in situ, which provides actionable information to test hypotheses.Galloway, B.J., Dewing, K., Beauchamp, B., 2018. Upper Paleozoic hydrocarbon systems in the Sverdrup Basin, Canadian Arctic Islands. Marine and Petroleum Geology 92, 809-821. upper Paleozoic (Carboniferous to Permian) succession of the Sverdrup Basin in the Canadian Arctic Islands has the potential to contain significant hydrocarbon reserves, though it has never been a primary exploration target. To better constrain previous estimates and hydrocarbon play possibilities, this study completed evaluations of source rock quality and extent and thermal maturity. This study also incorporated new understandings of reservoir units and their stratigraphic relation to source rocks, trapping configurations and timing of hydrocarbon migration. Several hydrocarbon source units were identified within the upper Paleozoic formations of the Sverdrup Basin including the Emma Fiord, Trappers Cove, Antoinette, Assistance, Sabine Bay, van Hauen and Trold Fiord formations. The Emma Fiord and Trold Fiord formations are both found to be oil prone, with the remainder of the sources being gas prone. The upper Paleozoic succession is interpreted to be gas prone due to dominant kerogen types and high average thermal maturity. Many of the older concept plays put forth for the upper Paleozoic succession have been determined to be unviable. However, modern plays that implement new understandings of the basin have the potential to be viable. This study has found that the upper Paleozoic succession of the Sverdrup Basin is promising for gas discoveries with new plays such as salt diapirism plays, or plays similar to the Barents Sea Gohta play. New hydrocarbon rock source data also suggests the potential for a new oil and gas play on northern Prince Patrick Island. This new research could lead to significant resource discoveries that have been previously overlooked.Gan, Y.M., Towers, J., Bradley, R.A., Pearson, E., Nowell, G., Peterkin, J., Montgomery, J., 2018. Multi-isotope evidence for cattle droving at Roman Worcester. Journal of Archaeological Science: Reports 20, 6-17. enamel from six cattle mandibles excavated from Roman deposits at The Hive development site, Worcester (mid-2nd to early 4th century AD) was subjected to strontium, oxygen and carbon isotope analyses (87Sr/86Sr, δ18O and δ13C) to investigate the movement of cattle into Worcester, a purported regional cattle market, during the Roman period. Strontium isotope ratios show that none of the cattle were born and bred in close proximity to Worcester and arrived as mature beasts some time before death. Whilst two are consistent with origins in the region of Old Red Sandstone of Herefordshire to the west, the unusually high strontium isotope ratios of four of the cattle (i.e. >0.714) show that they originated in a region of ancient or radiogenic rocks such as granites which are found only in the west and north of Britain (e.g. Wales, the Lake District and northern Scotland) based on the currently available biosphere data. Comparison of the oxygen and carbon isotope values also suggests that the cattle were not from the same herd, but interpretation is complicated by the lack of comparative cattle data for the Roman period as well as other time periods. The severe wear of the molars from the aged cattle in this study also limits the interpretation of the results. More isotopic analyses are needed from other British sites in order to fully understand the implications of cattle movement into urban centres during the Roman period.Gao, Y., Liu, K., Zhao, X., Li, H., Cui, Y., Xin, G., Sun, B., 2018. Prediction of wax precipitation region in wellbore during deep water oil well testing. Petroleum Exploration and Development 45, 351-357. deep water oil well testing, the low temperature environment is easy to cause wax precipitation, which affects the normal operation of the test and increases operating costs and risks. Therefore, a numerical method for predicting the wax precipitation region in oil strings was proposed based on the temperature and pressure fields of deep water test string and the wax precipitation calculation model. And the factors affecting the wax precipitation region were analyzed. The results show that: the wax precipitation region decreases with the increase of production rate, and increases with the decrease of geothermal gradient, increase of water depth and drop of water-cut of produced fluid, and increases slightly with the increase of formation pressure. Due to the effect of temperature and pressure fields, wax precipitation region is large in test strings at the beginning of well production. Wax precipitation region gradually increases with the increase of shut-in time. These conclusions can guide wax prevention during the testing of deep water oil well, to ensure the success of the test.Garaniya, V., McWilliam, D., Goldsworthy, L., Ghiji, M., 2018. Extensive chemical characterization of a heavy fuel oil. Fuel 227, 67-78. paper presents procedures for determining the fractions, chemical compositions and combustion characteristics of Heavy Fuel Oil (HFO). This chemical characterization is requisite for better prediction of thermodynamic behaviour of multicomponent fuel such as HFO which consist of thousands of different components. Detailed chemical and physical compositions, molecular weight range and mean molecular weight of individual fractions of fuel enable to use more advanced approaches such as continuous thermodynamics for simulation and modelling. Sequential elution solvent chromatography was used to separate a HFO into Saturates, Aromatics, Resins and Asphaltenes (SARA) as gas chromatographic analysis was unsatisfactory to reveal the overall composition of a HFO, due to the insufficient volatility in most of the heavy compounds. Subsequent mass spectrometric and elemental analysis showed a wide range of molecular weight distributions for the fractions. The results also indicate that the saturates fraction contains cyclic structures with aliphatic side chains while the aromatics fraction contains tetracyclic aromatic rings with aliphatic side chains. The degree of difference between the Thermo-Gravimetric Analysis (TGA) scans of the fractions in inert and oxidizing atmospheres observed at high temperatures also increases with the degree of functionality of the fractions due to the presumably greater extent of free radical chemistry occurring in an oxidizing environment. The Infrared spectra of the fractions are consistent with what would be expected from a consideration of the solvents used to elute them in column chromatography and supported the classification of the fractions.Garcia, G.G., Garcia, A.J.V., Henriques, M.H.P., 2018. Palynology of the Morro do Chaves Formation (Lower Cretaceous), Sergipe Alagoas Basin, NE Brazil: Paleoenvironmental implications for?the early history of the South Atlantic. Cretaceous Research 90, 7-20. break-up of Gondwana and the origin of related source rocks and reservoir intervals of the Brazilian coastal basins are being increasingly studied in the last decades. In this context the Sergipe-Alagoas Basin, which lies to the north of the Campos Basin hydrocarbon province, becomes relevant for the completeness of its depositional sequences. This paper presents, for the first time, the detailed palynological record from the Morro do Chaves Formation, located at the InterCement Quarry, near S?o Miguel dos Campos, Alagoas. The analysis of samples from the mudstone intervals of the unit mainly composed by coquinas has enabled new biostratigraphic, paleoenvironmental and paleogeographic interpretations of the evolution of the South Atlantic. The occurrence of the species Dicheiropollis etruscus, with a vertical distribution ranging from the Berriasian to the Barremian, supports the late Barremian age for the lowermost part of the Morro do Chaves Formation, traditionally interpreted as having been deposited in a lacustrine environment, close to herbaceous plants, surrounded by remote mountainous areas with arboreal vegetation. The occurrence of algae phycomata of the Class Prasinophyceae, associated with Scenedesmus and Botryoccocus, organisms that tolerate some salinity in its uppermost part, together with other biotic and abiotic data, corroborate the possibility of relating the Morro do Chaves Formation to a marine and/or brackish depositional environment, which may have resulted from a marine flooding in the northern sector of the Sergipe-Alagoas Basin during Early Cretaceous times. The results of this work support a paleogeographic model characterized by an episodic input of Tethyan waters towards the north of the South American continent.Ga?parovi?, B., Penezi?, A., Frka, S., Kazazi?, S., Lampitt, R.S., Holguin, F.O., Sudasinghe, N., Schaub, T., 2018. Particulate sulfur-containing lipids: Production and cycling from the epipelagic to the abyssopelagic zone. Deep Sea Research Part I: Oceanographic Research Papers 134, 12-22. are major gaps in our understanding of the distribution and role of lipids in the open ocean especially with regard to sulfur-containing lipids (S-lipids). Here, we employ a powerful analytical approach based on high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to elucidate depth-related S-lipid production and molecular transformations in suspended particulate matter from the Northeast Atlantic Ocean in this depth range. We show that within the open-ocean environment S-lipids contribute up to 4.2% of the particulate organic carbon, and that up to 95% of these compounds have elemental compositions that do not match those found in the Nature Lipidomics Gateway database (termed “novel”). Among the remaining 5% of lipids that match the database, we find that sulphoquinovosyldiacylglycerol (SQDG) are efficiently removed while sinking through the mesopelagic zone. The relative abundance of other assigned lipids (sulphoquinovosylmonoacylglycerol (SQMG), sulfite and sulfate lipids, Vitamin D2 and D3 derivatives, and sphingolipids) did not change substantially with depth. The novel S-lipids, represented by hundreds of distinct elemental compositions (160–300?molecules at any one depth), contribute increasingly to the lipid and particulate organic matter pools with increased depth. Depth-related transformations cause (i) incomplete degradation/transformation of unsaturated S-lipids which leads to the depth-related accumulation of the refractory saturated compounds with reduced molecular weight (average 455?Da) and (ii) formation of highly unsaturated S-lipids (average abyssopelagic molecular double bond equivalents, DBE=7.8) with lower molecular weight (average 567?Da) than surface S-lipids (average 592?Da). A depth-related increase in molecular oxygen content is observed for all novel S-lipids and indicates that oxidation has a significant role in their transformation while (bio)hydrogenation possibly impacts the formation of saturated compounds. The instrumentation approach applied here represents a step change in our comprehension of marine S-lipid diversity and the potential role of these compounds in the oceanic carbon cycle. We describe a very much higher number of compounds than previously reported, albeit at the level of elemental composition and fold-change quantitation with depth, rather than isomeric confirmation and absolute quantitation of individual lipids. We emphasize that saturated S-lipids have the potential to transfer carbon from the upper ocean to depth and hence are significant vectors for carbon sequestration.Gaunitz, C., Fages, A., Hangh?j, K., Albrechtsen, A., Khan, N., Schubert, M., Seguin-Orlando, A., Owens, I.J., Felkel, S., Bignon-Lau, O., de Barros Damgaard, P., Mittnik, A., Mohaseb, A.F., Davoudi, H., Alquraishi, S., Alfarhan, A.H., Al-Rasheid, K.A.S., Crubézy, E., Benecke, N., Olsen, S., Brown, D., Anthony, D., Massy, K., Pitulko, V., Kasparov, A., Brem, G., Hofreiter, M., Mukhtarova, G., Baimukhanov, N., L?ugas, L., Onar, V., Stockhammer, P.W., Krause, J., Boldgiv, B., Undrakhbold, S., Erdenebaatar, D., Lepetz, S., Mashkour, M., Ludwig, A., Wallner, B., Merz, V., Merz, I., Zaibert, V., Willerslev, E., Librado, P., Outram, A.K., Orlando, L., 2018. Ancient genomes revisit the ancestry of domestic and Przewalski’s horses. Science 360, 111-114.. The Eneolithic Botai culture of the Central Asian steppes provides the earliest archaeological evidence for horse husbandry, ~5500 years ago, but the exact nature of early horse domestication remains controversial. We generated 42 ancient-horse genomes, including 20 from Botai. Compared to 46 published ancient- and modern-horse genomes, our data indicate that Przewalski’s horses are the feral descendants of horses herded at Botai and not truly wild horses. All domestic horses dated from ~4000 years ago to present only show ~2.7% of Botai-related ancestry. This indicates that a massive genomic turnover underpins the expansion of the horse stock that gave rise to modern domesticates, which coincides with large-scale human population expansions during the Early Bronze Age.Editor's Summary: Revisiting the origins of modern horses. The domestication of horses was very important in the history of humankind. However, the ancestry of modern horses and the location and timing of their emergence remain unclear. Gaunitz et al. generated 42 ancient-horse genomes. Their source samples included the Botai archaeological site in Central Asia, considered to include the earliest domesticated horses. Unexpectedly, Botai horses were the ancestors not of modern domestic horses, but rather of modern Przewalski's horses. Thus, in contrast to current thinking on horse domestication, modern horses may have been domesticated in other, more Western, centers of origin.Ge, X., Shen, C., Selby, D., Wang, J., Ma, L., Ruan, X., Hu, S., Mei, L., 2018. Petroleum-generation timing and source in the northern Longmen Shan thrust belt, Southwest China: Implications for multiple oil-generation episodes and sources. American Association of Petroleum Geologists Bulletin 102, 913-938. temporal evolution of hydrocarbons (～500 million bbl) and its relationship to the orogenic events of the Longmen Shan thrust belt have been extensively debated. The hydrocarbons occur as solid bitumen, as dykes and/or coatings within/along faults/fractures, and as present-day oil seeps. Here, utilizing organic geochemistry, we demonstrate that all of the bitumen exhibit similar organo-geochemical characteristics, and were sourced from the upper Neoproterozoic–lower Cambrian Doushantuo and Qiongzhusi Formations. In contrast, the organic geochemistry of the present-day oil seeps are distinct from that of the bitumen, and suggest that the source is the Permian Dalong Formation.Bitumen Re-Os data indicate that the upper Neoproterozoic–lower Cambrian Doushantuo and Qiongzhusi Formations underwent two temporally distinct oil-generation events; initial oil generation occurred during the Late Cambrian/Early Ordovician prior to the Caledonian orogeny, and secondly during the Jurassic (～165 Ma) coinciding with the Indosinian-Yanshan orogenies. In contrast, the Re-Os data of the present-day oil seeps are too similar to yield a meaningful age, although the source is considered to have undergone hydrocarbon maturation between the Triassic and Jurassic. The temporal hydrocarbon evolution in the Longmen Shan thrust belt also provides an understanding of the hydrocarbon evolution and future exploration of the adjacent petroliferous Sichuan Basin.Gentzis, T., Carvajal-Ortiz, H., Deaf, A., Tahoun, S.S., 2018. Multi-proxy approach to screen the hydrocarbon potential of the Jurassic succession in the Matruh Basin, North Western Desert, Egypt. International Journal of Coal Geology 190, 29-41. paper discusses the hydrocarbon potential of the Jurassic succession in a mature basin in Egypt as an important element of a larger petroleum system study. Prior to any organic petrographic and organic geochemical analyses, a palynological age dating of the originally undifferentiated Jurassic sequence was carried out to identify different formations under investigation. This was based on key bioevents of some recovered dinoflagellate cysts and the identified lithology. Palynological, TOC/Rock Eval pyrolysis (including modified Rock-Eval methods), and vitrinite reflectance (VRo%) data from a total of 14 samples taken from the uppermost lower-upper Jurassic sequence represented by the Wadi Natrun (Toarcian-Aalenian), Khatatba (late Bathonian-Callovian), and Masajid (Oxfordian) formations in the Abu Tunis-1× well, are presented. In addition, two samples from the Abu Tunis-1× well and the proximal (~32km to the east) Siqueifa-1× well, having the highest remaining hydrocarbon potential (S2 yields), were analyzed and their results were compared using modified pyrolysis programs. Although the data showed a good correlation between the TAI of the palynomorph assemblage, vitrinite reflectance, and Tmax from Rock-Eval pyrolysis in the shallower intervals, the correlation between VRo and Tmax was poor in the lower half of the studied succession (middle Khatatba and Wadi Natrun formations). The very low Tmax values indicate immature OM while VRo and TAI indicated middle stage of oil window to past peak oil generation. The reason for this discrepancy is that the deeper samples are reservoir rocks, not source rocks, and the majority of the organic matter is not composed of reactive kerogen but consists of migrated hydrocarbons and NSO compounds. Contamination due to oil-based mud (OBM) was eliminated because the Abu Tunis-1× well was drilled in 1969, prior to the extensive use of OBM in drilling. This study showed that a multi-proxy approach is the best way to screen the hydrocarbon potential in a thick succession that contains interbedded source and reservoir rocks.Ghalayini, R., Nader, F.H., Bou Daher, S., Hawie, N., Chbat, W.E., 2018. Petroleum systems of Lebanon: An update and review. Journal of Petroleum Geology 41, 189-214. paper presents a new interpretation of the Levant margin, offshore Lebanon, with a review of Lebanese onshore geology and a new evaluation of the petroleum systems of the Eastern Mediterranean. Here, we divide the Lebanese onshore and offshore into four domains: the distal Levant Basin, the Lattakia Ridge, the Levant margin, and the onshore. Each domain is characterised by a particular structural style and stratigraphic architecture, resulting in different source‐reservoir‐trap configurations. This new division draws attention to specific areas of exploration interest in which there are distinct petroleum systems. Following a review of previously published data, this study presents new results from stratigraphic, structural and geochemical investigations. The results include a new interpretation of the Levant margin, focussing on the carbonate‐dominated stratigraphy of this area and its petroleum potential. New petroleum systems charts are presented for each of the four domains to refine and summarize the updated geological knowledge.Giraldo-Dávila, D., Chacón-Pati?o, M.L., Ramirez-Pradilla, J.S., Blanco-Tirado, C., Combariza, M.Y., 2018. Selective ionization by electron-transfer MALDI-MS of vanadyl porphyrins from crude oils. Fuel 226, 103-111. are biomarkers derived from chlorophyll, bacteriochlorophyll and the heme group, commonly present in crude oils as vanadyl or nickel complexes. These compounds, which despite of the organic matter maturation process preserve the tetrapyrrolic core of their precursors, show low polydispersity, concentration and are commonly used in geochemistry to assess oil lithology, oxidation-reduction conditions, geothermal maturation, conversion of organic matter, and burial depth. The physicochemical characteristics of petroporphyrins make them excellent analytes for MALDI-MS. Electron transfer (ET) ionization in MALDI, using novel electron transfer matrices based on cyano-phenylenevinylenes (e.g. CNPV-CH3), allows direct observation of labile compounds such as polyaromatics and porphyrin-like compounds, chlorophylls and pigments, as has been previously demonstrated by our group. In this work, we analyze petroporphyrins from two South American heavy oils using CNPV-CH3 as ET MALDI matrix. Petroporphyrins were isolated by Soxhlet extraction, with acetonitrile, followed by fractionation using normal-phase column chromatography. UV–Vis measurements showed a strong absorption band at 408?nm assigned to porphyrin Soret band for some chromatographic fractions. The fractions enriched with petroporphyrins were subjected to ET MALDI analysis. We demonstrate the suitability of the CNPV-CH3 MALDI matrix for the efficient and selective desorption and ionization of vanadyl porphyrins, when compared with a commercial MALDI matrix (DCTB) and LDI conditions.Godini, K., Samarghandi, M.R., Zafari, D., Rahmani, A.R., Afkhami, A., Arabestani, M.R., 2018. Isolation and identification of new strains of crude oil degrading bacteria from Kharg Island, Iran. Petroleum Science and Technology 36, 869-874. bacteria were isolated from polluted sites in Kharg Island, which is one of the most important ports for oil export in Iran. Both biochemical tests and 16S rRNA were applied to identify the strains. Experiments were performed in a mineral salt medium containing 2% of crude oil as the sole carbon. The results illustrated that the strains were: Brevibacillus sp., Microbacterium oxydans, Staphylococcus arlettae, Staphylococcus warneri, Methylobacterium persicinum, and Achromobacter xylosoxidans. Growth rates of these strains by its optical densities at the wavelength of 600 illustrated that Pseudomonas sp. (accession no. KC771232) had the highest growth rate (OD600 0.8).Gong, Y., Liu, K., Liu, S., 2018. Determining the occurrence of oil in micro/nanopores of tight sand: A new approach using environmental scanning electron microscopy combined with energy-dispersive spectrometry. Energy & Fuels 32, 4885-4893. use of fluorescence slices and other regular methods tend to be limited in resolution as a result of optical microscopy issues when they are applied to characterize oil occurrences in tight sand micro/nanopores. To address this, an experimental method that combines the use of environmental scanning electron microscopy (ESEM) and energy-dispersive spectrometry (EDS) is proposed in this paper on the basis of a large number of experiments; oil was observed during these tests using ESEM, and the carbon (C) content was qualitatively evaluated using EDS. Data show that the most appropriate experimental parameters were a sample room pressure of 10 Pa, a working distance of 5 mm, a working voltage of 15 kV, and an electronic beam spot size of 4.5 nm. The experimental analysis of six samples from five wells within the Songliao and Sichuan Basins, China, reveals that oil mainly occurs in the form of oil films and oil droplets within micro-intergranular seams, micro/nano-intergranular pores, and nano-intragranular pores. Observations aslo show that oil films are found mainly within micro-intergranular seams and micro-intergranular pores, while oil droplets, in contrast, are mainly found within nano-intragranular pores. Data show that the occurrence space occupied by oil films is relatively larger, having planar dimensions between 200 nm and 10 μm by between 1 and 10 μm. The oil films adhere to the pores just like bonding with the pores. The content of the C element in the oil films is 50–90%. In contrast, the occurrence space occupied by oil droplets is relatively smaller, with intragranular pore plane dimensions predominantly between 200 and 1000 nm by between 200 and 1000 nm. Data also show that oil droplets are controlled by the shape of intragranular pores and occur at scales between 200 and 1000 nm by between 200 and 1000 nm. Thus, although the occurrence space occupied by oil droplets is smaller than that of oil films, the development of numerous intragranular dissolved pores provides the necessary room for oil droplets to occur. The EDS data of these droplets show that the content of the C element of the oil droplets in intragranular pores is relatively small, mainly concentrated between 15 and 30%.Gonzalez, J.L., de Faria, E.L., Albuquerque, M.P., Albuquerque, M.P., Bom, C.R., Freitas, J.C.C., Cremasco, C.W., Correia, M.D., 2018. Representative elementary volume for simulations based on X-ray microtomography of sedimentary rock. Journal of Petroleum Science and Engineering 166, 906-912. porous systems like natural rocks, many phenomenological models have been developed in order to study the correlations between physical properties and the pore structure of these systems. The high resolution obtained with X-ray microtomography (μCT) images (micro or nanometer scales) has allowed exploring in details the complex morphology of the pore space in natural rocks. This has promoted the development of numerical simulations at the pore-scale level aiming to improve our comprehension about the correlations between pore structure and macroscopic physical properties. In this respect, simulations of nuclear magnetic resonance properties performed directly on μCT images are very important, since petrophysical properties can be predicted using a realistic model for the heterogeneous porous structure. Also these simulations can include a specific morphology of the pore geometry, which can be controlled in order to verify the different hypotheses introduced during N M R interpretation of physical properties, like for example, permeability predictions and/or fluid typing. In addition, N M R simulations allow to study the existence of a representative volume of the whole system, whose experimental determination is a major challenge. In this work, nuclear magnetic relaxations are simulated on a pore geometry obtained from microtomography of a natural rock formation, localized in the southeast of Brazil. The simulations were performed through a discrete random-walk algorithm computed at the pore scale. In the simulations bulk relaxation was not considered, while the relaxation rate at the surface of the pores was assumed constant. Our results indicate that the relaxation curves can be considered representatives of the whole system for volumes above a representative volume with dimensions of some cubic millimeters. In addition, this representative elementary volume seems to be of the same order that the one found from the analyses of the porosity on the same digital rock. In summary, this study points out to the importance of verifying the existence of this characteristic volume during N M R simulations directly on images obtained from tomography, in order to ensure the reliability of the information obtained from the numerical simulations.Goodwin, D.G., Adeleye, A.S., Sung, L., Ho, K.T., Burgess, R.M., Petersen, E.J., 2018. Detection and quantification of graphene-family nanomaterials in the environment. Environmental Science & Technology 52, 4491-4513. increase in production of commercial products containing graphene-family nanomaterials (GFNs) has led to concern over their release into the environment. The fate and potential ecotoxicological effects of GFNs in the environment are currently unclear, partially due to the limited analytical methods for GFN measurements. In this review, the unique properties of GFNs that are useful for their detection and quantification are discussed. The capacity of several classes of techniques to identify and/or quantify GFNs in different environmental matrices (water, soil, sediment, and organisms), after environmental transformations, and after release from a polymer matrix of a product is evaluated. Extraction and strategies to combine methods for more accurate discrimination of GFNs from environmental interferences as well as from other carbonaceous nanomaterials are recommended. Overall, a comprehensive review of the techniques available to detect and quantify GFNs are systematically presented to inform the state of the science, guide researchers in their selection of the best technique for the system under investigation, and enable further development of GFN metrology in environmental matrices. Two case studies are described to provide practical examples of choosing which techniques to utilize for detection or quantification of GFNs in specific scenarios. Because the available quantitative techniques are somewhat limited, more research is required to distinguish GFNs from other carbonaceous materials and improve the accuracy and detection limits of GFNs at more environmentally relevant concentrations.Gordadze, G.N., Poshibaeva, A.R., Giruts, M.V., Perevalova, A.A., Koshelev, V.N., 2018. Formation of petroleum hydrocarbons from prokaryote biomass: 1. Formation of petroleum biomarker hydrocarbons from Thermoplasma sp. archaea biomass. Petroleum Chemistry 58, 186-189. hydrocarbon biomarkers (n-alkanes, isoprenanes, pregnanes, steranes, cheilanthanes, hopanes) in the soluble part and thermolysis products of the insoluble part of the biomass of Thermoplasma sp. archaea isolated from the Neftyanaya Ploshchadka hot spring of the Uzon volcano caldera (Kamchatka, Russia) have been identified by gas chromatography–mass spectrometry. The distribution of these hydrocarbons resembles that of slightly transformed marine oils generated in argillaceous-carbonate strata, a fact that is confirmed by Rock-Eval pyrolysis data for the biomass of the archaea studied. Original Russian Text ? G.N. Gordadze, A.R. Poshibaeva, M.V. Giruts, A.A. Perevalova, V.N. Koshelev, 2018, published in Neftekhimiya, 2018, Vol. 58, No. 2, pp. 135–139.G?tz, A.E., Ruckwied, K., Wheeler, A., 2018. Marine flooding surfaces recorded in Permian black shales and coal deposits of the Main Karoo Basin (South Africa): Implications for basin dynamics and cross-basin correlation. International Journal of Coal Geology 190, 178-190. marine origin of black shales in the context of the Permian postglacial development of the Karoo Basin, South Africa, is subject of an ongoing controversial discussion. Here, we present and discuss palynological and sedimentological data providing evidence of a transgressive event during the early Guadalupian. Palynofacies assemblages of the black shales of the southern basin include marine phytoplankton that exhibit peak abundance within the Whitehill shales and which also occur within siltstones and glauconitic sandstones on top of the No. 5 coal seam of the north-eastern basin. Palynostratigraphic control makes this marine signal a powerful tool for cross-basin correlation. Moreover, palynofacies analysis demonstrates a facies transition from terrestrial lacustrine and fluvio-deltaic in the northeast to deep marine in the south-western parts of the basin.Grady, M.M., Wright, I.P., Engrand, C., Siljestr?m, S., 2018. The Rosetta mission and the chemistry of organic species in Comet 67P/Churyumov–Gerasimenko. Elements 14, 95-100. are regarded as probably the most primitive of solar system objects, preserving a record of the materials from which the solar system aggregated. Key amongst their components are organic compounds – molecules that may trace their heritage to the interstellar medium from which the protosolar nebula eventually emerged. The most recent cometary space mission, Rosetta, carried instruments designed to characterize, in unprecedented detail, the organic species in comet 67P/Churyumov–Gerasimenko (67P). Rosetta was the first mission to match orbits with a comet and follow its evolution over time, and also the first mission to land scientific instruments on a comet surface. Results from the mission revealed a greater variety of molecules than previously identified and indicated that 67P contained both primitive and processed organic entities.Graw, M.F., D'Angelo, G., Borchers, M., Thurber, A.R., Johnson, J.E., Zhang, C., Liu, H., Colwell, F.S., 2018. Energy gradients structure microbial communities across sediment horizons in deep marine sediments of the South China Sea. Frontiers in Microbiology 9, 729. doi: 10.3389/fmicb.2018.00729. deep marine subsurface is a heterogeneous environment in which the assembly of microbial communities is thought to be controlled by a combination of organic matter deposition, electron acceptor availability, and sedimentology. However, the relative importance of these factors in structuring microbial communities in marine sediments remains unclear. The South China Sea (SCS) experiences significant variability in sedimentation across the basin and features discrete changes in sedimentology as a result of episodic deposition of turbidites and volcanic ashes within lithogenic clays and siliceous or calcareous ooze deposits throughout the basin's history. Deep subsurface microbial communities were recently sampled by the International Ocean Discovery Program (IODP) at three locations in the SCS with sedimentation rates of 5, 12, and 20 cm per thousand years. Here, we used Illumina sequencing of the 16S ribosomal RNA gene to characterize deep subsurface microbial communities from distinct sediment types at these sites. Communities across all sites were dominated by several poorly characterized taxa implicated in organic matter degradation, including Atribacteria, Dehalococcoidia, and Aerophobetes. Sulfate-reducing bacteria comprised only 4% of the community across sulfate-bearing sediments from multiple cores and did not change in abundance in sediments from the methanogenic zone at the site with the lowest sedimentation rate. Microbial communities were significantly structured by sediment age and the availability of sulfate as an electron acceptor in pore waters. However, microbial communities demonstrated no partitioning based on the sediment type they inhabited. These results indicate that microbial communities in the SCS are structured by the availability of electron donors and acceptors rather than sedimentological characteristics.Greathouse, J.A., Boyle, T.J., Kemp, R.A., 2018. Computational evaluation of Mg–salen compounds as subsurface fluid tracers: Molecular dynamics simulations in toluene–water mixtures and clay mineral nanopores. Energy & Fuels 32, 4969-4978. tracers that can be selectively placed underground and uniquely identified at the surface using simple on-site spectroscopic methods would significantly enhance subsurface fluid monitoring capabilities. To ensure their widespread utility, the solubility of these tracers must be easily tuned to oil- or water-wet conditions as well as reducing or eliminating their propensity to adsorb onto subsurface rock and/or mineral phases. In this work, molecular dynamics simulations were used to investigate the relative solubilities and mineral surface adsorption properties of three candidate tracer compounds comprising Mg–salen derivatives of varying degrees of hydrophilic character. Simulations in water–toluene liquid mixtures indicate that the partitioning of each Mg–salen compound relative to the interface is strongly influenced by the degree of hydrophobicity of the compound. Simulations of these complexes in fluid-filled mineral nanopores containing neutral (kaolinite) and negatively charged (montmorillonite) mineral surfaces reveal that adsorption tendencies depend upon a variety of parameters, including tracer chemical properties, mineral surface type, and solvent type (water or toluene). Simulation snapshots and averaged density profiles reveal insight into the solvation and adsorption mechanisms that control the partitioning of these complexes in mixed liquid phases and nanopore environments. This work demonstrates the utility of molecular simulation in the design and screening of molecular tracers for use in subsurface applications.Grimaldi, C., Marcy, G.W., Tellis, N.K., Drake, F., 2018. Area coverage of expanding E.T. Signals in the galaxy: SETI and Drake's N. arXiv:1802.09399 [physics.pop-ph]. Milky Way Galaxy contains an unknown number, N , of civilizations that emit electromagnetic radiation (of unknown wavelengths) over a finite lifetime, L . Here we are assuming that the radiation is not produced indefinitely, but within L as a result of some unknown limiting event. When a civilization stops emitting, the radiation continues traveling outward at the speed of light, c , but is confined within a shell wall having constant thickness, cL . We develop a simple model of the Galaxy that includes both the birthrate and detectable lifetime of civilizations to compute the possibility of a SETI detection at the Earth. Two cases emerge for radiation shells that are (1) thinner than or (2) thicker than the size of the Galaxy, corresponding to detectable lifetimes, L , less than or greater than the light-travel time, ～100,000 years, across the Milky Way, respectively. For case (1), each shell wall has a thickness smaller than the size of the Galaxy and intersects the galactic plane in a donut shape (annulus) that fills only a fraction of the Galaxy's volume, inhibiting SETI detection. But the ensemble of such shell walls may still fill our Galaxy, and indeed may overlap locally, given a sufficiently high birthrate of detectable civilizations. In the second case, each radiation shell is thicker than the size of our Galaxy. Yet, the ensemble of walls may or may not yield a SETI detection depending on the civilization birthrate. We compare the number of different electromagnetic transmissions arriving at Earth to Drake's N , the number of currently emitting civilizations, showing that they are equal to each other for both cases (1) and (2). However, for L<100,000 years, the transmissions arriving at Earth may come from distant civilizations long extinct, while civilizations still alive are sending signals yet to arrive.Grodnitskaya, I.D., Karpenko, L.V., Syrtsov, S.N., Prokushkin, A.S., 2018. Microbiological parameters and peat stratigraphy of two types of bogs in the northern part of the Sym–Dubches Interfluve (Krasnoyarsk Krai). Biology Bulletin 45, 160-170. phytocenotic and microbiological features of two types of bogs (oligotrophic and eutrophic) in the northern part of the Sym–Dubches interfluve (the middle taiga subzone in the Yenisei region of Siberia) have been studied. The descriptions of the plant cover of bogs and peat stratigraphy and age are given. It has been revealed that peat of the bogs studied is characterized by a low or medium ash content; a small amount of N, P, and K; and an acid and slightly acid reaction, which results in their moderate microbial and fermentation activity and favors accumulation and conservation of plant remains and microbial biomass. It has been proved that the microbocenoses of the eutrophic and oligotrophic bogs are characterized by a stable ecophysiological status of the natural norm. Original Russian Text ? I.D. Grodnitskaya, L.V. Karpenko, S.N. Syrtsov, A.S. Prokushkin, 2018, published in Izvestiya Akademii Nauk, Seriya Biologicheskaya, 2018, No. 2, pp. 179–190.Groucutt, H.S., Grün, R., Zalmout, I.A.S., Drake, N.A., Armitage, S.J., Candy, I., Clark-Wilson, R., Louys, J., Breeze, P.S., Duval, M., Buck, L.T., Kivell, T.L., Pomeroy, E., Stephens, N.B., Stock, J.T., Stewart, M., Price, G.J., Kinsley, L., Sung, W.W., Alsharekh, A., Al-Omari, A., Zahir, M., Memesh, A.M., Abdulshakoor, A.J., Al-Masari, A.M., Bahameem, A.A., Al Murayyi, K.M.S., Zahrani, B., Scerri, E.L.M., Petraglia, M.D., 2018. Homo sapiens in Arabia by 85,000 years ago. Nature Ecology & Evolution 2, 800-809. the timing and character of the expansion of Homo sapiens out of Africa is critical for inferring the colonization and admixture processes that underpin global population history. It has been argued that dispersal out of Africa had an early phase, particularly ~130–90 thousand years ago (ka), that reached only the East Mediterranean Levant, and a later phase, ~60–50?ka, that extended across the diverse environments of Eurasia to Sahul. However, recent findings from East Asia and Sahul challenge this model. Here we show that H. sapiens was in the Arabian Peninsula before 85?ka. We describe the Al Wusta-1 (AW-1) intermediate phalanx from the site of Al Wusta in the Nefud desert, Saudi Arabia. AW-1 is the oldest directly dated fossil of our species outside Africa and the Levant. The palaeoenvironmental context of Al Wusta demonstrates that H. sapiens using Middle Palaeolithic stone tools dispersed into Arabia during a phase of increased precipitation driven by orbital forcing, in association with a primarily African fauna. A Bayesian model incorporating independent chronometric age estimates indicates a chronology for Al Wusta of ~95–86?ka, which we correlate with a humid episode in the later part of Marine Isotope Stage 5 known from various regional records. Al Wusta shows that early dispersals were more spatially and temporally extensive than previously thought. Early H. sapiens dispersals out of Africa were not limited to winter rainfall-fed Levantine Mediterranean woodlands immediately adjacent to Africa, but extended deep into the semi-arid grasslands of Arabia, facilitated by periods of enhanced monsoonal rainfall.Guan, Z., Wang, M., Cai, Y., Yang, H., Zhao, M., Zhao, C., 2018. Rapid characterization of the chemical constituents of Sijunzi decoction by UHPLC coupled with Fourier transform ion cyclotron resonance mass spectrometry. Journal of Chromatography B 1086, 11-22. decoction, a renowned Chinese prescription has long been utilized to treat gastrointestinal problems. In the context of this research work, the use of Ultra high performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry was made to separate and characterize the components of Sijunzi decoction. The performance of Liquid chromatography was carried out on a C8 column (150?mm?×?2.1?mm, 1.8?μm); moreover, the mobile phase were consisted of 0.2% formic acid (A) and acetonitrile (B). In accordance with the findings, characterization of 120 chemical compounds was performed by liquid chromatography with mass spectrometry. The key constituents among them included ginsenosides (in Radix Ginseng), 16 triterpene carboxylic acids (in Poria), sesquiterpenes (in Rhizoma Atractylodis Macrocephalae), triterpenesaponins (in Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle) as well as flavonoids (in Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle) in Sijunzi decoction. This research developed the bases for prospective research associated with Sijunzi decoction, together with being expected to be useful to rapidly extract and characterize the constituents in other Traditional Chinese herbal formulations.Guo, Q., Littke, R., Zieger, L., 2018. Petrographical and geochemical characterization of sub-bituminous coals from mines in the Cesar-Ranchería Basin, Colombia. International Journal of Coal Geology 191, 66-79. coals from the La Jagua and Calenturitas coal mines in the Cesar sub-basin, Colombia were investigated for the first time using organic-petrological and organic-geochemical methods to assess the thermal maturity and palaeoenvironmental conditions during peat accumulation. Thirteen seams were sampled from the Los Cuervos formation at two mines. Evaluation based on organic petrological analyses and Rock-Eval pyrolysis reveals that the coals are thermally immature and of sub-bituminous B to sub-bituminous A rank with a predominance of type III, mixed with type II kerogen. 22S/(22S?+?22R) homohopane, Ts/(Ts?+?Tm), MPI, MPR and 1-MP/9-MP ratios are very low. This low thermal maturity corresponds to high volatile matter contents.Petrographically, the La Jagua and Calenturitas coals are dominated by vitrinite, with low to high amounts of inertinite and low to moderate amounts of liptinite. The detailed petrographic data indicate a predominantly herbaceous plant input and oxidative conditions during deposition, mostly with strong tissue destruction. Further conclusions are deduced from petrographic ratios such as tissue preservation-, gelification-, groundwaterAC- and vegetation indices, ash- and sulfur contents, iso- and n-alkane distribution, and 17α(H)-homohopane ratio. In summary, the data support a formation in tropical, ombrogenic, rather wet peats with high bacterial activity.Gutiérrez Sama, S., Farenc, M., Barrère-Mangote, C., Lobinski, R., Afonso, C., Bouyssière, B., Giusti, P., 2018. Molecular fingerprints and speciation of crude oils and heavy fractions revealed by molecular and elemental mass spectrometry: Keystone between petroleomics, metallopetroleomics, and petrointeractomics. Energy & Fuels 32, 4593-4605. and its fractions are some of the most complex mixtures found in analytical chemistry. Mass spectrometry currently plays an increasing role in the characterization of these matrices. Since the last review on this topic in 2011, several new approaches have been introduced, and these approaches increasingly use sample fractionation by extraction and/or liquid chromatographic techniques. This review considers molecular mass spectrometry (with special emphasis on the use of ion mobility) and inorganic mass spectrometry. The combination of both techniques paves the way to “petrointeractomic” approaches, which are introduced as a novel, important part of “petroleomic” approaches.Gutsanu, V., 2018. Chemical–mineralogical systems that are able to generate nitrogen compounds on Earth and even Mars. ACS Earth and Space Chemistry 2, 340-346. formation of nitrogen compounds by chemical fixing of atmospheric nitrogen in ambient conditions in only one technological step is of particular interest for the chemical industry and science. The effect is achieved by air bubbling through the reactor containing a cross-linked ionic polymer with strongly basic functional groups and sulfate solution of a trivalent metal. The lower the temperature of the reactor, the higher the yield production of nitrogen compounds. In the polymer phase, jarosite-type compound formation occurs that participates in the redox processes, followed by the partial destruction and synthesis of nitrogen compounds. The results from this work demonstrate that, under certain conditions, systems containing a strongly basic cross-linked polymer and solution of three valence metal sulfates (Fe3+, Ga3+, and others) are able to generate nitrogen-containing compounds, using atmospheric nitrogen. The spontaneous and uncontrolled processes of nitrogen compound generation could occur in nature, which would explain the stability of some minerals on Earth and even Mars.Haagh, M.E.J., Schilderink, N., Duits, M.H.G., Siretanu, I., Mugele, F., Collins, I.R., 2018. Salinity-dependent contact angle alteration in oil/brine/silicate systems: The effect of temperature. Journal of Petroleum Science and Engineering 165, 1040-1048. understand the success of low salinity water flooding in improving oil recovery, it is important to identify the molecular scale mechanisms that control the wettability and thus the adhesion between oil and rock. Previous experiments have attributed the wettability alteration in core flood experiments either to the expansion of the electric double layer or to multicomponent ion exchange reactions or a combination of both. Here, we explore changes of the contact angle of brine droplets on mica in ambient oil (n-decane plus added fatty acid) at variable temperature as a function of the concentration of mono- and divalent cations. For 20?°C and 40?°C, we find that the contact angle decreases by up to 30° with decreasing divalent cation concentration but remains constant upon decreasing the total salinity by removing only monovalent cations, i.e. upon double layer expansion at constant divalent cation concentration. At 60?°C, we find a remarkable increase of the water contact angle of artificial sea water to values of approximately 120°. This value decreases upon dilution to values in the range of 10–40?°C, where the lowest values are again only obtained upon removing the divalent cations. These findings corroborate the conclusion of earlier measurements at room temperature that divalent cations play an essential role in controlling the wettability of carboxylic acid groups to mineral surface, presumably in an ion bridging type mechanism. We also demonstrate that the contact angle reduction occurs very quickly upon flushing a sessile droplet of artificial sea water with divalent cation-free or simply diluted brine, suggesting fast equilibration as required for a successful tertiary water flooding process. Our experiments also demonstrate that, despite the simplicity of the present system, the origins of wettability alteration are rather complex and that synergistic effects can lead to dramatic variations such as the unexpectedly high contact angle at 60?°C.Haas, S., de Beer, D., Klatt, J.M., Fink, A., Rench, R.M., Hamilton, T.L., Meyer, V., Kakuk, B., Macalady, J.L., 2018. Low-light anoxygenic photosynthesis and Fe-S-biogeochemistry in a microbial mat. Frontiers in Microbiology 9, 858. doi: 10.3389/fmicb.2018.00858. report extremely low-light-adapted anoxygenic photosynthesis in a thick microbial mat in Magical Blue Hole, Abaco Island, The Bahamas. Sulfur cycling was reduced by iron oxides and organic carbon limitation. The mat grows below the halocline/oxycline at 30 m depth on the walls of the flooded sinkhole. In situ irradiance at the mat surface on a sunny December day was between 0.021 and 0.084 μmol photons m-2 s-1, and UV light (<400 nm) was the most abundant part of the spectrum followed by green wavelengths (475–530 nm). We measured a light-dependent carbon uptake rate of 14.5 nmol C cm-2 d-1. A 16S rRNA clone library of the green surface mat layer was dominated (74%) by a cluster (>97% sequence identity) of clones affiliated with Prosthecochloris, a genus within the green sulfur bacteria (GSB), which are obligate anoxygenic phototrophs. Typical photopigments of brown-colored GSB, bacteriochlorophyll e and (β-)isorenieratene, were abundant in mat samples and their absorption properties are well-adapted to harvest light in the available green and possibly even UV-A spectra. Sulfide from the water column (3–6 μmol L-1) was the main source of sulfide to the mat as sulfate reduction rates in the mats were very low (undetectable-99.2 nmol cm-3 d-1). The anoxic water column was oligotrophic and low in dissolved organic carbon (175–228 μmol L-1). High concentrations of pyrite (FeS2; 1–47 μmol cm-3) together with low microbial process rates (sulfate reduction, CO2 fixation) indicate that the mats function as net sulfide sinks mainly by abiotic processes. We suggest that abundant Fe(III) (4.3–22.2 μmol cm-3) is the major source of oxidizing power in the mat, and that abiotic Fe-S-reactions play the main role in pyrite formation. Limitation of sulfate reduction by low organic carbon availability along with the presence of abundant sulfide-scavenging iron oxides considerably slowed down sulfur cycling in these mats.Hakimi, M.H., Abdullah, W.H., Alqudah, M., Makeen, Y.M., Mustapha, K.A., Hatem, B.A., 2018. Pyrolysis analyses and bulk kinetic models of the Late Cretaceous oil shales in Jordan and their implications for early mature sulphur-rich oil generation potential. Marine and Petroleum Geology 91, 764-775. this study, oil shale samples were collected from Late Cretaceous Muwaqaar Chalk Marl Formation (MCM) in Jordan to study their petrologic and organic geochemical properties. Pyrolysis and bulk kinetic techniques were performed on the Late Cretaceous oil shales. The results of this study were used to characterize the different organofacie types in the Late Cretaceous oil shales and their effect on the petroleum type generated during thermal maturation and the temperature of petroleum generation. On the basis of the geochemical results, the analysed Late Cretaceous oil shales contain predominantly Type II and rarely Type I kerogens. These kerogens are consistent with the high dominate of sapropel organic matter (i.e., alginite and amorphous organic matter). A good correlation is noted between increasing abundance of organic matter and the kerogen type that was derived from an open pyrolysis–gas chromatography (Py–GC). The Py–GC data indicate the analysed oil shale samples contain heterogeneous organic matter of the kerogen Type II-S. It is interesting to know that this sulphur-rich kerogen (Type II-S) can generate high sulphur oils at low maturity ranges. This is consistent with the predicted temperature petroleum generation from bulk kinetic models. The bulk kinetic models in this study indicate that the main phase of petroleum formation from the thermally immature Late Cretaceous oil shales occur between 122 and 148?°C. These temperature values of the petroleum generation are generally consistent with the kerogen type II-S and further indicate that the analysed oil shale samples can generate sulfur-rich oils at early stage of kerogen cracking.Hakimi, M.H., Al-Matary, A.M., Salad Hersi, O., 2018. Burial and thermal history reconstruction of the Mukalla-Sayhut Basin in the Gulf of Aden, Yemen: Implications for hydrocarbon generation from Paleocene potential source rock. Journal of African Earth Sciences 144, 59-75. this study, four exploratory wells from the Mukalla-Sayhut Basin, Gulf of Aden are used for basin modeling study in order to simulate the petroleum generation and expulsion history of the Umm Er Radhuma Formation.The basin models illustrate that the Gulf of Aden is an extensional rift basin and initially developed during Oligocene as indicated by paleo-heat flow values. The heat flow reached peak heat-flow values of approximately 120–160 mW/m2 at Early to Middle Oligocene time. This high paleo-heat flow had a considerable effect on the Paleocene Umm Er Radhuma source rock and cooking of the organic matter. The basin models also indicate that the Umm Er Radhuma Formation source rock had passed the peak-oil generation window during the late Oligocene (Chattian) age. Onset of oil-generation began during late Rupelian age (～29 Ma), whereas the main oil was generated during the Chattian age (27-24 Ma). The models also show that the petroleum was expelled from the Umm Er Radhuma source rock since latest Oligocene (late Chattian, < 24Ma) time, with transformation ratio of more than 50%. These basin models suggest that the Umm Er Radhuma Formation is an effective source rock where significant amount of petroleum is expected to be generated and expelled to any nearby potential reservoir rocks within the Mukalla-Sayhut Basin.Hakimi, M.H., Al-Sufi, S.A., 2018. Organic geochemistry investigations of crude oils from Bayoot oilfield in the Masila Basin, east Yemen and their implication for origin of organic matter and source-related type. Egyptian Journal of Petroleum 27, 37-54. crude oil samples from fractured basement reservoir rocks in the Bayoot oilfield, Masila Basin were studied to describe oil characteristics and to provide information on the source of organic matter input and the genetic link between oils and their potential source rock in the basin. The bulk geochemical results of whole oil and gasoline hydrocarbons indicate that the Bayoot oils are normal crude oil, with high hydrocarbons of more than 60%. The hydrocarbons are dominated by normal, branched and cyclic alkanes a substantial of the light aromatic compounds, suggesting aliphatic oil-prone kerogen. The high abundant of normal, branched and cyclic alkanes also indicate that the Bayoot oils are not biodegradation oils.The biomarker distributions of isoprenoid, hopane, aromatic and sterane and their cross and triangular plots suggest that the Bayoot oils are grouped into one genetic family and were generated from marine clay-rich source rock that received mixed organic matter and deposited under suboxic conditions. The biomarker distributions of the Bayoot oils are consistent with those of the Late Jurassic Madbi source rock in the basin. Biomarker maturity and oil compositions data also indicate that the Bayoot oils were generated from mature source rock with peak oil-window maturity.Haltigin, T., Lange, C., Mugnuolo, R., Smith, C., iMARS Working Group, 2018. iMARS Phase 2. Astrobiology 18, S1-S131. International Mars Exploration Working Group (IMEWG) was formed in 1993 to provide a forum for the international coordination of Mars exploration. In 2007, IMEWG chartered the international Mars Architecture for the Return of Samples Working Group (iMARS WG), which produced a Phase 1 report in 2008 (iMARS, 2008). In 2014, IMEWG chartered an iMARS Phase 2 Working Group, comprising two panels of experts: (i) Engineering and (ii) Science/Earth Operations. The iMARS Phase 2 WG was tasked to provide: ·A status report on planning for a Mars Sample Return (MSR) campaign, building on missions and international developments achieved since the iMARS Phase 1 WG issued its report; and·Recommendations for progressing toward campaign implementation, including a proposed sample management plan.This report presents the iMARS Phase 2 WG’s findings. It details top-level campaign requirements that would meet stated science objectives and planetary protection constraints. It presents an updated reference MSR architecture, made of three flight elements and one ground element (termed the 3+1 architecture). It provides technical and programmatic justifications for this architecture and report also discusses alternatives to the reference architecture. The WG also reports on the status of MSR technology developments conducted by several space agencies around the world, evidence of the willingness of major space stakeholders to invest in MSR implementation. This report elaborates on programmatic considerations relating to MSR, including campaign robustness, international coordination and decision-making, a provisional implementation timeline, and a possible cost-sharing model.In this report, the WG presents: ·A returned-sample management plan, including an organizational structure for an international Mars sample science institute that outlines roles and responsibilities of key members and describes sample return facility requirements;·A science implementation plan, covering preliminary sample examination flow, sample allocation process, and data policies; and·A Mars sample curation plan, including sample tracking and routing procedures, sample sterilization considerations, and long-term archiving recommendations.The WG’s key conclusions are that: ·It is feasible to return scientifically selected samples from Mars in 2031/33 under the proposed mission architecture, technology development roadmap, and sample management plan. A successful campaign will depend on early and binding agreements for long-term commitments by participating organisations.·Returning samples from Mars will require a multidisciplinary approach. Scientific, safety and curatorial aspects of the campaign must each be considered and integrated when developing mission architecture and sample management structure.·While the Mars exploration community has made progress in understanding planetary protection implications of MSR and associated technology developments, important requirements and protocols remain to be further developed.The WG’s key recommendations are that: ·To advance development of MSR architecture, interested international partners must declare their interests, define a cooperation framework, and determine their contributions.·An internationally-tasked and -accepted planetary protection protocol for MSR should be produced as soon as possible, as this protocol will have technical and programmatic implications for the mission architecture.·MSR campaign partners should establish an international MSR Science Institute as part of the campaign’s governance structure upon approval to return samples from Mars.·Two key MSR enabling technologies, the Mars ascent vehicle and sample containment (“break-the-chain-of-contact”), require further investments to proceed with development.Han, R., Liu, T., Li, F., Li, X., Chen, D., Wu, Y., 2018. Dependence of secondary mineral formation on Fe(II) production from ferrihydrite reduction by Shewanella oneidensis MR-1. ACS Earth and Space Chemistry 2, 399-409. dissimilatory iron reduction and secondary mineral formation by Shewanella oneidensis MR-1 have been widely recognized, questions remain about the effects of biogenic Fe(II) on the rate and extent of secondary mineral formation and the importance of biogenic Fe(II)-induced crystallization processes. In this study, we investigated the effects of different mutants of MR-1 on the bioreduction and mineralization of ferrihydrite. The results indicate that while the reduction rates of ferrihydrite by ΔmtrD, ΔmtrF, and ΔomcA are similar to that of the wild type (WT), the capacity to reduce ferrihydrite decreased dramatically in the mutants ΔcymA and ΔmtrA. The order for Fe(III) reduction by MR-1 WT and mutants was ranked as follows: WT ≈ ΔmtrD ≈ ΔmtrF > ΔomcA > ΔmtrC > ΔcymA > ΔmtrA. Secondary minerals of ferrihydrite were characterized using X-ray diffraction, Fourier transform infrared spectra, and scanning electron microscopy. The results show that goethite and hematite were the main secondary minerals formed during the first 2 days in all treatments, and then magnetite appeared in the WT, ΔmtrD, ΔmtrF and ΔomcA treatments, whereas magnetite began to appear from the sixth day onward in the ΔmtrC treatment. However, no magnetite was observed during the 6 days in the ΔmtrA and ΔcymA incubation treatments. The plausible electron transfer pathways of bioreduction and phase transformation were also verified using thermodynamic calculations of elementary reactions. This study clarified the importance of Fe(II) production in secondary mineral formation processes and highlighted the significance of biogenic Fe(II)-catalyzed crystallization. This information may, in turn, help us to better understand natural microbe–mineral interaction processes.Han, Y., Poetz, S., Mahlstedt, N., Karger, C., Horsfield, B., 2018. Fractionation of pyrrolic nitrogen compounds compounds during primary migration of petroleum within the Barnett Shale sequence of Marathon 1 Mesquite Well, Texas. Energy & Fuels 32, 4638-4650. primary migration of petroleum has been recently described in detail for a thermally mature core of the Barnett Shale with almost nonvariant organofacies and maturity. Here, we use samples from the same well to provide new insights into the fractionation of pyrrolic nitrogen compounds during primary migration. Using gas chromatography–mass spectrometry (GC-MS), a decrease in concentration of carbazoles and benzocarbazoles was observed which correlated with migration distance. However, a preferential removal of individual isomers like benzocarbazole[a] relative to benzocarbazole[c] could not be detected. Enlarging the analytical window, we studied the effect of primary migration on high molecular weight nitrogen-containing compounds using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) combined with electrospray ionization (ESI) in the negative ion mode. Compounds with one or two nitrogen atoms are most abundant. Among the N1 compounds, those with 12, 15, 18, 20, and 23 double bond equivalents (DBEs) were dominating classes representing carbazole-type compounds (among others) with one to three ortho-annelated benzene rings (12, 15, and 18) and four to five ortho- and peri-annelated benzene rings (20, 23). In comparison, the N2 compound class mainly consists of compounds with 12, 15, 17, 20, and 23 DBEs representing (among other compounds) biindoles with zero to one ortho-annelated benzene ring (12, 15) and carbazolocarbazoles with zero to two ortho-annelated benzene rings (17, 20, and 23). A relative enrichment of biindole-type compounds relative to carbazolocarbazoles in migrated petroleum was shown. This might indicate that aromatic compounds with separated ring systems like biindoles are less strong retained in the source rock than fully annelated polycyclic aromatic compounds like carbazolocarbazoles. Within individual DBE classes of N1 and N2 compounds, very similar carbon number (CN) distributions were illustrated for nonmigrated and migrated fluids, i.e., a predominance of C0–5 alkylated homologues maximizing at C2 or C3 substitutes. Regardless of fractionation, the overall similar distributions in DBE and CN suggest that pyrrolic nitrogen-containing compounds have restricted precursors and common mechanisms of formation. Nonfluorescent chlorophyll catabolites (NCCs), the final breakdown products of chlorophyll, were tentatively suggested as possible precursors.Hao, J., Giovenco, E., Ulysse, P.-S., Gilles, M., Isabelle, D., 2018. Compatibility of amino acids in ice Ih: Implications for the origin of life. Astrobiology 18, 381-392. Icy environments may have been common on early Earth due to the faint young sun. Previous studies have proposed that the formation of large icy bodies in the early ocean could concentrate the building blocks of life in eutectic fluids and, therefore, facilitate the polymerization of monomers. This hypothesis is based on the untested assumption that organic molecules are virtually incompatible in ice Ih (hexagonal ice). In this study, we conducted freezing experiments to explore the partitioning behavior of selected amino acids (AAs; glycine, l-alanine, l-proline, and l-phenylalanine) between ice Ih and aqueous solutions analogous to seawater. We allowed ice crystals to grow slowly from a few seeds in equilibrium with the solution and used Raman spectroscopy to analyze in situ the relative concentrations of AAs in the ice and aqueous solution. During freezing, there was no precipitation of AA crystals, indicating that the concentrations in solution never reached their solubility limit, even when the droplet was mostly frozen. Analyses of the Raman spectra of the ice and eutectic solution suggested that considerable amounts of AAs existed in the ice phase with partition coefficients varying between 0.2 and 0.5. These observations imply little incompatibility of AAs in ice Ih during the freezing of the solutions, rendering the concentration hypothesis in a eutectic system unwarranted. However, incorporation into ice Ih could protect AAs from decomposition or racemization and significantly improve the efficiency of extraterrestrial transport of small organics. Therefore, this study supports the hypothesis of extraterrestrial delivery of organic molecules in icy comets and asteroids to the primitive Earth as suggested by an increasing number of independent observations.Hao, Y., Yuan, L., Li, P., Zhao, W., Li, D., Lu, D., 2018. Molecular simulations of methane adsorption behavior in illite nanopores considering basal and edge surfaces. Energy & Fuels 32, 4783-4796. adsorption properties of methane (CH4) have a great influence on shale gas exploration and development. The surface chemistry characteristics of nanopores are key factors in adsorption phenomena. The clay pores in shale formations exhibit basal surface and edge surfaces (mainly as A and C chain and B chain surfaces in illite). Little research regarding CH4 adsorption on clay edge surfaces has been carried out despite their distinct surface chemistries. In this work, the adsorption of CH4 confined in nanoscale illite slit pores with basal and edge surfaces was investigated by grand canonical Monte Carlo and molecular dynamics simulations. The adsorbed phase density, adsorption capacity, adsorption energy, isosteric heat of adsorption, and adsorption sites were calculated and analyzed. The simulated adsorption capacity compares favorably with the available experimental data. The results show that the edge surfaces have van der Waals interactions that are weaker than those of the basal surfaces. The adsorption capacity follows the order basal surface > B chain surface > A and C chain surface. However, the differences of adsorption capacity between these surfaces are small; thus, edge surfaces cannot be ignored in shale formation. Additionally, we confirmed that the adsorbed phase has a thickness of approximately 0.9 nm. The pore size determines the interaction overlap strength on the gas molecules, and the threshold value of the pore size is about 2 nm. The preferential adsorption sites locate differently on edge and basal surfaces. These findings could provide deep insights into CH4 adsorption behavior in natural illite-bearing shales.Harayama, T., Riezman, H., 2018. Understanding the diversity of membrane lipid composition. Nature Reviews Molecular Cell Biology 19, 281-296. membranes are formed from a chemically diverse set of lipids present in various amounts and proportions. A high lipid diversity is universal in eukaryotes and is seen from the scale of a membrane leaflet to that of a whole organism, highlighting its importance and suggesting that membrane lipids fulfil many functions. Indeed, alterations of membrane lipid homeostasis are linked to various diseases. While many of their functions remain unknown, interdisciplinary approaches have begun to reveal novel functions of lipids and their interactions. We are beginning to understand why even small changes in lipid structures and in composition can have profound effects on crucial biological functions.Hargan, K.E., Stewart, E.M., Michelutti, N., Grooms, C., Kimpe, L.E., Mallory, M.L., Smol, J.P., Blais, J.M., 2018. Sterols and stanols as novel tracers of waterbird population dynamics in freshwater ponds. Proceedings of the Royal Society B: Biological Sciences 285, Article 20180631. the expansion of urban centres in the mid-twentieth century and the post-1970 decrease in pesticides, populations of double-crested cormorants (Phalacrocorax auritus) and ring-billed gulls (Larus delawarensis) around Lake Ontario (Canada and USA) have rapidly rebounded, possibly to unprecedented numbers. Along with the use of traditional palaeolimnological methods (e.g. stable isotopes, biological proxies), we now have the capacity to develop specific markers for directly tracking the presence of waterbirds on nesting islands. Here, we apply the use of lipophilic sterols and stanols from both plant and animal-faecal origins as a reliable technique, independent of traditional isotopic methods, for pinpointing waterbird arrival and population growth over decadal timescales. Sterol and stanol concentrations measured in the guano samples of waterbird species were highly variable within a species and between the three species of waterbirds examined. However, cholesterol was the dominant sterol in guano, and phytosterols were also high in ring-billed gull guano. This variability highlights a specialist piscivorous diet for cormorants compared to a generalist, omnivorous diet for gulls, which may now often include grain and invertebrates from agricultural fields. A ratio that includes cholesterol and sitosterol plus their aerobically reduced products (cholestanol, stigmastanol) best explained the present range of bird abundance across the islands and was significantly correlated to sedimentary δ15N. Overall, we demonstrate the use of sterols and stanols as a direct means for tracking the spatial and temporal presence of waterbirds on islands across Lake Ontario, and probably elsewhere.Hassanpouryouzband, A., Yang, J., Tohidi, B., Chuvilin, E., Istomin, V., Bukhanov, B., Cheremisin, A., 2018. CO2 capture by injection of flue gas or CO2–N2 mixtures into hydrate reservoirs: dependence of CO2 capture efficiency on gas hydrate reservoir conditions. Environmental Science & Technology 52, 4324-4330. of flue gas or CO2–N2 mixtures into gas hydrate reservoirs has been considered as a promising option for geological storage of CO2. However, the thermodynamic process in which the CO2 present in flue gas or a CO2–N2 mixture is captured as hydrate has not been well understood. In this work, a series of experiments were conducted to investigate the dependence of CO2 capture efficiency on reservoir conditions. The CO2 capture efficiency was investigated at different injection pressures from 2.6 to 23.8 MPa and hydrate reservoir temperatures from 273.2 to 283.2 K in the presence of two different saturations of methane hydrate. The results showed that more than 60% of the CO2 in the flue gas was captured and stored as CO2 hydrate or CO2-mixed hydrates, while methane-rich gas was produced. The efficiency of CO2 capture depends on the reservoir conditions including temperature, pressure, and hydrate saturation. For a certain reservoir temperature, there is an optimum reservoir pressure at which the maximum amount of CO2 can be captured from the injected flue gas or CO2–N2 mixtures. This finding suggests that it is essential to control the injection pressure to enhance CO2 capture efficiency by flue gas or CO2–N2 mixtures injection.Hayakawa, C., Fujii, K., Funakawa, S., Kosaki, T., 2018. Effects of sorption on biodegradation of low-molecular-weight organic acids in highly-weathered tropical soils. Geoderma 324, 109-118. molecular weight organic acids (LMWOAs) are key pools regulating carbon (C) stabilization and destabilization in tropical forest soils. The variation in clay contents and mineralogy between sites or within a profile might regulate magnitude of LMWOA sorption and biodegradation in tropical soils poor in short-range-order (SRO) Al/Fe oxides. We analyzed soil solution concentration, sorption isotherms, and mineralization kinetics of 14C-radiolabeled acetate, oxalate, citrate, and glucose. The sorption capacities of LMWOAs increased with clay contents, but not with the abundance of SRO clay minerals. Sorption can reduce mineralization rates of multivalent LMWOAs (oxalate and citrate) and its effects could increase with increasing clay contents, especially in the clay-rich Bt horizon or in the clayey soil profile. The microbial respiration rates from LMWOAs and monosaccharides are primarily regulated by substrate availability and microbial biomass in the tropical soils, while mineralization of multivalent LMWOAs can be limited by sorption especially in the clayey soil horizon or profile. The smaller sorption capacities in the organic and sandier soil horizons could contribute to fast turnover of organic matters through LMWOA pools in tropical forest soils.He, J., Wang, J., Yu, Q., Liu, W., Ge, X., Yang, P., Wang, Z., Lu, J., 2018. Pore structure of shale and its effects on gas storage and transmission capacity in well HD-1 eastern Sichuan Basin, China. Fuel 226, 709-720. is proved that the Wufeng-Longmaxi formation in Sichuan Basin is the key shale gas layer in China. Although the breakthrough of shale gas exploration had been gotten in it, the enrichment mechanism of it has not been well studied. To understand the enrichment mechanism of it, we will take the biggest total gas content layer (BTGC layer) and main production layer (MP layer) drilled in well HD-1 for example. A series of experiments were conducted on core samples, including total organic carbon (TOC) content, X-ray diffraction (XRD), scanning electron microscope (SEM), focused ion beam scanning electron microscope (FIB-SEM) and Micro-CT. Meanwhile, the aid tests (such as mud logging data, reservoir physical test, field desorption experiment data, mud gas logging data) were integrated to study the difference of the two sections in gas storage and transmission capacity too. The results show that although the field desorption gas content of BTGC layer is bigger than MP layer, the TOC of BTGC layer (3.45%) is smaller than it in MP layer (4.15%). The MP layer is dominated by the quartz with average value 87.3% which is obviously bigger than it in BTGC layer 37.5%. Although the helium porosity in BTGC layer (2.98%) is bigger than MP layer (2.68%), the permeability of it(0.005878mD) is smaller than MP layer(0.013950mD). Except the organic pores, to a certain type, the pores in the MP layer are bigger than them in BTGC layer, such as interparticle pores, dissolution pores, micro fractures. The connected pores are dominated by the pores in mm-scale and micro-scale. The difference of the enrichment mechanism in the two layers is dominated by the difference of pore structure. The MP layer provides a migration pathway to the gas enriched from nearby shale layer in km-scale. If the permeability and the overpressure of the layer are big enough, the shale gas would be exploited without hydraulic fracturing. In BTGC layer, the pores are scatted in the shale and isolated from each other. The gas storage ability of this type is commonly good, with high field desorption gas content, but it must be exploited with hydraulic fracturing for its low permeability. It is need to pay attention to the high permeability layer in shale strata in the further exploration of shale gas.Hemingway, J.D., Hilton, R.G., Hovius, N., Eglinton, T.I., Haghipour, N., Wacker, L., Chen, M.-C., Galy, V.V., 2018. Microbial oxidation of lithospheric organic carbon in rapidly eroding tropical mountain soils. Science 360, 209-212.: Lithospheric organic carbon (“petrogenic”; OCpetro) is oxidized during exhumation and subsequent erosion of mountain ranges. This process is a considerable source of carbon dioxide (CO2) to the atmosphere over geologic time scales, but the mechanisms that govern oxidation rates in mountain landscapes are poorly constrained. We demonstrate that, on average, 67 ± 11% of the OCpetro initially present in bedrock exhumed from the tropical, rapidly eroding Central Range of Taiwan is oxidized in soils, leading to CO2 emissions of 6.1 to 18.6 metric tons of carbon per square kilometer per year. The molecular and isotopic evolution of bulk OC and lipid biomarkers during soil formation reveals that OCpetro remineralization is microbially mediated. Rapid oxidation in mountain soils drives CO2 emission fluxes that increase with erosion rate, thereby counteracting CO2 drawdown by silicate weathering and biospheric OC burial.Editor's Summary: Microbes eat rocks and leave carbon dioxide. The reaction of atmospheric carbon dioxide (CO2) with silicate rocks provides a carbon sink that helps counterbalance the release of CO2 by volcanic degassing. However, some types of rocks contain petrogenic organic carbon, the oxidation of which adds CO2 to the atmosphere, counteracting the drawdown by silicates. Hemingway et al. present evidence from the rapidly eroding Central Range of Taiwan showing that microbes oxidize roughly two-thirds of the petrogenic organic carbon there and that the rate of oxidation increases with the rate of erosion.Hendy, J., Welker, F., Demarchi, B., Speller, C., Warinner, C., Collins, M.J., 2018. A guide to ancient protein studies. Nature Ecology & Evolution 2, 791-799. is an emerging neologism used to describe the application of mass spectrometry-based approaches to the study of ancient proteomes. As with palaeogenomics (the study of ancient DNA), it intersects evolutionary biology, archaeology and anthropology, with applications ranging from the phylogenetic reconstruction of extinct species to the investigation of past human diets and ancient diseases. However, there is no explicit consensus at present regarding standards for data reporting, data validation measures or the use of suitable contamination controls in ancient protein studies. Additionally, in contrast to the ancient DNA community, no consolidated guidelines have been proposed by which researchers, reviewers and editors can evaluate palaeoproteomics data, in part due to the novelty of the field. Here we present a series of precautions and standards for ancient protein research that can be implemented at each stage of analysis, from sample selection to data interpretation. These guidelines are not intended to impose a narrow or rigid list of authentication criteria, but rather to support good practices in the field and to ensure the generation of robust, reproducible results. As the field grows and methodologies change, so too will best practices. It is therefore essential that researchers continue to provide necessary details on how data were generated and authenticated so that the results can be independently and effectively evaluated. We hope that these proposed standards of practice will help to provide a firm foundation for the establishment of palaeoproteomics as a viable and powerful tool for archaeologists, anthropologists and evolutionary biologists.Henry, D.G., Jarvis, I., Gillmore, G., Stephenson, M., Emmings, J.F., 2018. Assessing low-maturity organic matter in shales using Raman spectroscopy: Effects of sample preparation and operating procedure. International Journal of Coal Geology 191, 135-151. Raman spectroscopy is used to assess the thermal maturity of organic matter in sedimentary rocks, particularly organic-rich mudstones. However, discrepancies exist between quantified Raman spectral parameters and maturity values obtained by vitrinite reflectance. This has prevented the adoption of a standard protocol for the determination of thermal maturity of organic matter (OM) by Raman spectroscopy. We have examined the factors influencing the Raman spectra obtained from low-maturity OM in potential shale gas reservoir rocks. The inconsistencies in Raman results obtained are due to three main factors that are critically evaluated: (1) different operational procedures, including experiment setup and spectral processing methods; (2) different methods of sample preparation; (3) the analysis of diverse types of OM. These factors are scrutinized to determine the sources of inconsistency and potential bias in Raman results, and guidance is offered on the development of robust and reproducible analytical protocols. We present two new Raman parameters for un-deconvolved spectra named the DA1/GA ratio (area ratio of 1100–1400?cm?1/1550–1650?cm?1) and SSA (scaled spectrum area: sum of total area between 1100 and 1700?cm?1) that offer potential maturity proxies. An automated spreadsheet procedure is presented that processes raw Raman spectra and calculates several of the most commonly used Raman parameters, including the two new variables.Hernández-Mesa, M., Le Bizec, B., Monteau, F., García-Campa?a, A.M., Dervilly-Pinel, G., 2018. Collision cross section (CCS) database: An additional measure to characterize steroids. Analytical Chemistry 90, 4616-4625. mobility spectrometry enhances the performance characteristics of liquid chromatography–mass spectrometry workflows intended to steroid profiling by providing a new separation dimension and a novel characterization parameter, the so-called collision cross section (CCS). This work proposes the first CCS database for 300 steroids (i.e., endogenous, including phase I and phase II metabolites, and exogenous synthetic compounds), which involves 1080 ions and covers the CCS of 127 androgens, 84 estrogens, 50 corticosteroids, and 39 progestagens. This large database provides information related to all the ionized species identified for each steroid in positive electrospray ionization mode as well as for estrogens in negative ionization mode. CCS values have been measured using nitrogen as drift gas in the ion mobility cell. Generally, direct correlation exists between mass-to-charge ratio (m/z) and CCS because both are related parameters. However, several steroids mainly steroid glucuronides and steroid esters have been characterized as more compact or elongated molecules than expected. In such cases, CCS results in additional relevant information to retention time and mass spectral data for the identification of steroids. Moreover, several isomeric steroid pairs (e.g., 5β-androstane-3,17-dione and 5α-androstane-3,17-dione) have been separated based on their CCS differences. These results indicate that adding the CCS to databases in analytical workflows increases selectivity, thus improving the confidence in steroids analysis. Consequences in terms of identification and quantification are discussed. Quality criteria and a construction of an interlaboratory reproducibility approach are also reported for the obtained CCS values. The CCS database described here is made publicly available.Herschy, B., Chang, S.J., Blake, R., Lepland, A., Abbott-Lyon, H., Sampson, J., Atlas, Z., Kee, T.P., Pasek, M.A., 2018. Archean phosphorus liberation induced by iron redox geochemistry. Nature Communications 9, Article 1346. element phosphorus (P) is central to ecosystem growth and is proposed to be a limiting nutrient for life. The Archean ocean may have been strongly phosphorus-limited due to the selective binding of phosphate to iron oxyhydroxide. Here we report a new route to solubilizing phosphorus in the ancient oceans: reduction of phosphate to phosphite by iron(II) at low (<200?°C) diagenetic temperatures. Reduction of phosphate to phosphite was likely widespread in the Archean, as the reaction occurs rapidly and is demonstrated from thermochemical modeling, experimental analogs, and detection of phosphite in early Archean rocks. We further demonstrate that the higher solubility of phosphite compared to phosphate results in the liberation of phosphorus from ferruginous sediments. This phosphite is relatively stable after its formation, allowing its accumulation in the early oceans. As such, phosphorus, not as phosphate but as phosphite, could have been a major nutrient in early pre-oxygenated oceans.Hiebert, R.S., Bekker, A., Houlé, M.G., Rouxel, O.J., 2018. Depositional setting of the Late Archean Fe oxide- and sulfide-bearing chert and graphitic argillite in the Shaw Dome, Abitibi greenstone belt, Canada. Precambrian Research 311, 98-116. chert-rich exhalite and graphitic argillite are the only sedimentary rocks deposited in deep-water settings during long-lived hiatuses in mafic to ultramafic volcanism within the Hart area of the Shaw Dome in the Late Archean Abitibi greenstone belt in Canada. The Fe oxide- and sulfide-bearing, but predominantly cherty, exhalite lithological unit in the Hart area can be traced laterally to iron formation elsewhere in the Shaw Dome. Whole-rock as well as Fe and S isotope geochemistry suggest that the exhalite unit was formed as a result of direct precipitation from seawater, distally from hydrothermal centres. Fractionation of Fe isotopes through the precipitation of iron oxyhydroxides in a neutrally buoyant hydrothermal plume removed the heavier isotopes of Fe, resulting in the negative δ56Fe values observed in the exhalite in the Hart area. Archean seawater is generally considered to be anoxic, but moderate Mn enrichments (up to 1.87?wt% MnO) in exhalite along with negative Fe isotope values resulting from partial Fe(II) oxidation suggest the presence of oxygen in the upper part of the water column along the pathway of hydrothermal plumes from their source to the depositional site in the Abitibi greenstone belt. In contrast, the graphitic argillite contains abundant pyrite nodules and bands that exhibit systematic negative Fe isotope values, but does not show Mn enrichment. This unit likely formed in a zone of upwelling of nutrient-rich waters from deeper parts of the basin resulting in high organic productivity. Both exhalite and graphitic argillite have negative Δ33S values, suggesting that sulfur was derived from seawater sulfate, which is consistent with an anoxic atmosphere with sulfate aerosols produced by photochemical reactions. Combined, our data indicates disequilibrium between anoxic atmosphere and partially oxygenated upper part of the water column during periods of volcanic quiescence in the?～2.7?Ga Abitibi greenstone belt supporting the existence of oxidized oases within the Archean ocean.Hildebrand, M., Lerch, S.J.L., Shrestha, R.P., 2018. Understanding diatom cell wall silicification—moving forward. Frontiers in Marine Science 5, 125. doi: 10.3389/fmars.2018.00125. silicified cell walls of diatoms have inspired the interest of researchers for several centuries, and our understanding of their properties and formation has developed in synch with the development of observational and analytical techniques. Over the past 20 years, approaches used to characterize the molecular components involved in cell wall silicification have evolved, and this has provided significant insights into fundamental aspects of silicification, and promises to continue to do so. Diatom cell wall formation is highly dynamic but, apart from microscopic investigations, most previous molecular characterizations have been on completely formed structures, and thus only provide information on a static end point in the process. However, recent studies that monitor when components are made, and how they are transported to the silica deposition vesicle (SDV), indicate that investigation into the true dynamics of the process is possible. Real-time imaging and genetic manipulation offer the promise of elucidating the spatio-temporal dynamics of, and interactions between, components, which will be essential to understand how structure formation is controlled and coordinated. This review is aimed at describing the approaches that have been used to characterize diatom silicification, integrating newer concepts based on results from diverse approaches, and raising questions that still need to be addressed, leveraging the diverse tools and techniques we now have.Hildenbrand, Z.L., Santos, I.C., Liden, T., Carlton Jr, D.D., Varona-Torres, E., Martin, M.S., Reyes, M.L., Mulla, S.R., Schug, K.A., 2018. Characterizing variable biogeochemical changes during the treatment of produced oilfield waste. Science of The Total Environment 634, 1519-1529. the forefront of the discussions about climate change and energy independence has been the process of hydraulic fracturing, which utilizes large amounts of water, proppants, and chemical additives to stimulate sequestered hydrocarbons from impermeable subsurface strata. This process also produces large amounts of heterogeneous flowback and formation waters, the subsurface disposal of which has most recently been linked to the induction of anthropogenic earthquakes. As such, the management of these waste streams has provided a newfound impetus to explore recycling alternatives to reduce the reliance on subsurface disposal and fresh water resources. However, the biogeochemical characteristics of produced oilfield waste render its recycling and reutilization for production well stimulation a substantial challenge. Here we present a comprehensive analysis of produced waste from the Eagle Ford shale region before, during, and after treatment through adjustable separation, flocculation, and disinfection technologies. The collection of bulk measurements revealed significant reductions in suspended and dissolved constituents that could otherwise preclude untreated produced water from being utilized for production well stimulation. Additionally, a significant step-wise reduction in pertinent scaling and well-fouling elements was observed, in conjunction with notable fluctuations in the microbiomes of highly variable produced waters. Collectively, these data provide insight into the efficacies of available water treatment modalities within the shale energy sector, which is currently challenged with improving the environmental stewardship of produced water management.Hillman, J.I.T., Klaucke, I., Bialas, J., Feldman, H., Drexler, T., Awwiller, D., Atgin, O., ?if?i, G., Badhani, S., 2018. Gas migration pathways and slope failures in the Danube Fan, Black Sea. Marine and Petroleum Geology 92, 1069-1084. large geophysical dataset, including bathymetry, and 2D and 3D P-cable seismic data, revealed evidence of numerous gas flares near the S2 Canyon in the Danube Fan, northwestern Black Sea. This dataset allows us to investigate potential relationships between gas migration pathways, gas vents observed at the seafloor and submarine slope failures. Vertical gas migration structures as revealed in the seismics appear to be concentrated near submarine slope failure structures. Where these seismically defined features extend upwards to the seafloor, they correlate with the location of gas flares. However, not all these structures reach the seafloor, in some cases because they are capped by overlying sediments. A strong correlation is inferred between gas migration pathways, heterogeneous mass transport deposits and contacts between adjacent units of contrasting lithology. Although missing age constrains prevent a final judgement, we discuss the potential relationship between submarine slope failures and gas migration in order to determine if gas migration is a precursor to failure, or if the presence of slope failures and associated mass transport deposits facilitates the migration of gas. Our observations indicate that lithological heterogeneity, mass transport deposits and minor sediment deformation control gas migration pathways and the formation of gas chimney-like features. Gas migration is focused and gradual, resulting in gas flares where the chimney-like features extend to the seafloor, with no evidence of erosive features such as pockmarks.Holbourn, A.E., Kuhnt, W., Clemens, S.C., Kochhann, K.G.D., J?hnck, J., Lübbers, J., Andersen, N., 2018. Late Miocene climate cooling and intensification of southeast Asian winter monsoon. Nature Communications 9, Article 1584. late Miocene offers the opportunity to assess the sensitivity of the Earth’s climate to orbital forcing and to changing boundary conditions, such as ice volume and greenhouse gas concentrations, on a warmer-than-modern Earth. Here we investigate the relationships between low- and high-latitude climate variability in an extended succession from the subtropical northwestern Pacific Ocean. Our high-resolution benthic isotope record in combination with paired mixed layer isotope and Mg/Ca-derived temperature data reveal that a long-term cooling trend was synchronous with intensification of the Asian winter monsoon and strengthening of the biological pump from ~7?Ma until ~5.5?Ma. The climate shift occurred at the end of a global δ13C decrease, suggesting that changes in the carbon cycle involving the terrestrial and deep ocean carbon reservoirs were instrumental in driving late Miocene climate cooling. The inception of cooler climate conditions culminated with ephemeral Northern Hemisphere glaciations between 6.0 and 5.5?Ma.Hol?apek, M., Liebisch, G., Ekroos, K., 2018. Lipidomic analysis. Analytical Chemistry 90, 4249-4257. state-of-art in the lipidomic analysis is summarized here to provide the overview of available sample preparation strategies, mass spectrometry (MS)-based methods for the qualitative analysis of lipids, and the quantitative MS approaches for high-throughput clinical workflows. Major challenges in terms of widely accepted best practices for lipidomic analysis, nomenclature, and standards for data reporting are discussed as well.Lipids are defined as hydrophobic or amphipathic small molecules that originate entirely or in part by carbanion-based condensations of thioesters and/or by carbocation-based condensations of isoprene units.(1) Older definitions of lipids refer them as molecules insoluble in water and soluble in organic solvents or molecules derived from fatty acids, but these old definitions do not cover all lipid molecules. The main biological functions of lipids are the energy storage, building blocks of cellular and subcellular membranes, and signaling molecules.(2) The dysregulation of lipids is related to various serious human diseases, such as cancer, Alzheimer disease, cardiovascular diseases, and lysosomal disorders.(3)Lipids belong to the last step in the “omic” cascade (Figure 1) starting from genome, through transcriptome, proteome, and finally to metabolome.(4) The first step in this cascade, genome, represents genotype and shows the predisposition of particular subject what may happen in the future based on the genetic information. The last step is the metabolome, which is representing the qualitative and quantitative information on all metabolites occurring in a particular biological system, defining the phenotype. Unlike the genome (predicting future consequences of genetic information), phenotype is reporting on the actual state of the organism, and hence is most convenient for biomarker discoveries of pathological states of organism including serious human diseases.Hosseininoosheri, P., Hosseini, S.A., Nu?ez-López, V., Lake, L.W., 2018. Impact of field development strategies on CO2 trapping mechanisms in a CO2–EOR field: A case study in the Permian Basin (SACROC unit). International Journal of Greenhouse Gas Control 72, 92-104. paper presents field-scale compositional reservoir flow modeling in the SACROC (Scurry Area Canyon Reef Operators Committee) unit, Permian Basin, to demonstrate the relative partitioning of CO2 during and after CO2 injection. The model was developed to study the effect of structural trapping, solubility trapping, and residual trapping on the partitioning of CO2 in oil, gas (free or residual), and brine phases over time. Furthermore, we investigated the impact of various injection scenarios, such as CGI (Continuous Gas Injection) and WAG (Water Alternating Gas), on the different trapping mechanisms. First, we used a high-resolution geocellular model, which was constructed from wireline logs, seismic surveys, core data, and stratigraphic interpretation. As the initial distribution of fluids plays an important role in CO2 partitioning, a comprehensive pressure-production history matching of primary, secondary, and tertiary recovery was completed. The hysteresis model was used to calculate the amount of CO2 trapped as residual. CO2 solubility into brine was verified based on previous experiments. The model results show a new understanding of relative CO2 partitioning in porous media. Although it was believed that structural trapping is the largest of the trapping mechanisms during CO2 injection and the first years of post-inject ion, our results show that in a carbonate field like SACROC, which contains a light oil, the solubility of CO2 in oil plays a very important role, even in the first stage of CO2 injection. Running a comprehensive history matching shows the deficiency of previous models to estimate the amount of trapped CO2 during and after the injection period. Among the various scenarios explored, WAG seems to be a promising operational approach to balance both storage and oil production. The present work provides valuable insights for optimizing oil production and CO2 storage in carbonate reservoirs like SACROC unit. In addition, this work helps decision makers to set storage goals based on optimized project risks.Hosseinpour, M., Fatemi, S., Ahmadi, S.J., Oshima, Y., Morimoto, M., Akizuki, M., 2018. Isotope tracing study on hydrogen donating capability of supercritical water assisted by formic acid to upgrade heavy oil: Computer simulation vs. experiment. Fuel 225, 161-173. to the increasing attention of the experts working in refineries on innovative techniques for heavy oil upgrading, the current research is focused on in-situ upgrading of heavy oil in supercritical water (SCW) assisted by formic acid. In dry condition, formic acid (FA) decomposes by two parallel paths, namely decarboxylation (HCOOH?→?H2?+?CO2) and dehydration (HCOOH?→?CO?+?H2O) to produce hydrogen and carbon mono oxide, respectively. Water-gas shift (WGS) reaction which is taken place by SCW and carbon monoxide provides active hydrogen (AH) as a more favorable hydrogen source for upgrading heavy oil in SC condition. In the current study, first, thermodynamic simulation of FA decomposition in SCW was studied to evaluate the contribution of hydrogen from water in Aspen suite environment by performing sensitivity analysis. Here, the effects of operational parameters (temperature, pressure, FA to water ratio) were studied on the above-mentioned reaction. The simulation results as well as experimental data show that the increase of FA to water ratio (FA/W) enhances the contribution of dehydration path, which means that SC works better as a precursor of hydrogen due to the higher concentrations of CO at SC condition. In order to specify the portion of hydrogen from WGS and decarboxylation reaction, the isotope labeling technique was applied by replacing ordinary water (H2O) with heavy water (D2O) in SC condition in the presence of heavy oil and FA. After combining the experimental data and Hansen solubility parameter of water (δH), it was revealed that temperature has dual effects which can influence on coking reaction by physical and chemical reaction. It means that an increasing in temperature can suppress the coke formation due to better miscibility of oil with water, while at an extreme temperature condition (500?°C), the dominant condensations of polycyclic aromatics are conspicuous; consequently the rate of coking is enhanced. High pressures (～45?MPa) also lead to the more coking reaction through the influence on the phase behavior of oil-water (δH and AH%) in which asphaltene conversion path is converted to coke rather than light products. Accordingly, T?=?450?°C and Pw?=?27?MPa were proposed respectively as an appropriate temperature and pressure for heavy oil upgrading in supercritical water assisted by FA to cause less coke and produce more light liquid products.Hou, X., Zhu, Y., Yao, H., 2018. Coupled accumulation characteristics of Carboniferous-Permian coal measure gases in the Northern Ordos Basin, China. Arabian Journal of Geosciences 11, Article 156. northern Ordos Basin provides a favorable geological environment for the accumulation and development of coal measure gases (CMG). The hydrocarbon generation potential and reservoir systems of the coal measures have been studied based on data from experimental tests and production and exploration wells, respectively. Further, the coupled accumulation characteristics were determined. The results show that the source rocks are characterized by favorable hydrocarbon generation potential, high thermal evolution (Ro%?=?1.3–2.3%), and mainly type III kerogen. Coals, typically aggregated organic matter, with a huge hydrocarbon generation potential (avg. 89.11?mg/g) and total organic content (TOC) (avg. 65.52%), are predominantly involved in gaseous hydrocarbon generation. Shales with good TOC contents (avg. 2.36%) and large cumulative thicknesses have an important role in gaseous hydrocarbon generation. Coal seams, shale layers, and sandstone layers occur as variably interbedded deposits, which form a favorable environment for CMG coupled accumulation. The porosity and permeability are ranked as follows: sandstone?>?coal?>?shale, with significant stress sensitivity and anisotropy. Two continuous gas generation peaks occurred in the Late Jurassic and Late Cretaceous, with an abundant amount of coal-derived and thermogenic gas generation, respectively. Potential gas-bearing sandstone layers can be formed by gas migration via short distances from nearby coal seams and shale layers. Coupled accumulation of CMG occurred in three stages: (1) stacked and interbedded reservoirs formation stage; (2) gas generating and charging stage; and (3) coupled accumulation adjustment stage. Coalbed methane (CBM)–tight sandstone gas (TSG) assemblage is a favorable target for CMG accumulation and development.Hovenden, M., Newton, P., 2018. Plant responses to CO2 are a question of time. Science 360, 263-264. carbon dioxide (CO2) concentrations in the atmosphere as a result of fossil fuel burning are expected to fertilize plants, resulting in faster growth. However, this change is not expected to be the same for all plants. Rather, scientists believe that differences in photosynthetic mechanism favor one plant group—the C3 plants—over the other, the C4 plants. On page 317 of this issue, Reich et al. (1) show that, although this expectation is met in the first few years of a long-term experiment, the situation reverses after 15 to 20 years, with important implications for future crop production and ecosystems.In 1966, Hatch and Slack (2) found that some plants have a distinct mechanism for assimilating CO2 from the atmosphere. This has profound ecological consequences. The ancestral method of photosynthesis combines CO2 with a five-carbon molecule to produce two identical three-carbon molecules. However, the enzyme that catalyzes this reaction also combines the same five-carbon compound with dioxygen, thus reducing the carbon assimilation rate and, hence, growth. Hatch and Slack discovered that some plants can avoid this by first combining CO2 from the atmosphere with a three-carbon molecule, producing a four-carbon molecule as the first stable product in photosynthesis. Plants with this pathway are known as C4 plants, distinguishing them from those with the ancestral pathway, termed C3 plants.Although only about 3% of the global plant species are C4 plants (3), they play a crucial role in many ecosystems, particularly savannas and grasslands (4, 5). C4 species contribute 25% of land biomass globally (3), provide forage for animals in both natural (for example, Serengeti) and managed (for example, Great Plains) grasslands, and contribute 14 of the world's 18 worst weeds (6). It is clearly important, therefore, to predict the future distribution and abundance of C4 plants.Reich et al. report findings from a 20-year experiment (see the photo) in the state of Minnesota, USA, where they exposed C3 and C4 plants to an elevated concentration of atmospheric CO2—arguably the most predictable global change. The C4 method of photosynthesis appears to have evolved during a period of declining atmospheric CO2 concentration and allows the plants to use CO2 more efficiently than C3 species (4). Today, the atmospheric CO2 concentration is higher than at any other time in the past 500,000 years and continues to rise (7). Most scientists expect C3 plants to benefit from this additional CO2 and outcompete C4 species, because C3 photosynthesis increases in efficiency with increasing CO2 concentration to a far greater extent than does C4 photosynthesis.Over the initial years of Reich et al.'s experiment, the results conformed to this expectation: C3 plants responded strongly to elevated CO2, whereas C4 plants were unresponsive. However, as the experiment progressed, the response of the C3 plants declined, and the response of the C4 plants became stronger. These changes were so marked and consistent that after 15 to 20 years, the response of C3 plants to CO2 was negligible but that of C4 plants was strong. Indeed, the growth stimulation from the CO2 in the C4 plants during the final 5 years of the experiment exceeded that in C3 plants at any stage of the experiment.Differences in photosynthesis rates or interannual variation in temperature and rainfall could not explain this result. What was important was how soil nitrogen dynamics changed in response to elevated CO2 and how this differed for the C3 and C4 plants. The growth response to elevated CO2 for both C3 and C4 species was directly and positively correlated to the effect of elevated CO2 on the net mineralization rate (that is, the rate at which soil nitrogen was converted from organic to inorganic forms).The availability of soil nitrogen to plants can have a strong influence on whether plants respond positively to elevated CO2 (8). Mineralization is a key factor in this availability. That the nitrogen mineralization rate increased over time in soil under C4 plants, but declined in soil under C3 plants, could therefore explain the growth responses. Thus, given sufficient time, the biogeochemical response to the rise in CO2 concentration appeared to overwhelm the initial, physiology-driven growth response.The different growth response of C3 and C4 species to elevated CO2 concentrations has important consequences. Earth system models assume a positive relationship between C3 plant growth and CO2 concentration, an assumption that Reich et al.'s results challenge. As a result, Earth's future carbon-sequestration potential could be far lower than predicted by these models, because most vegetation is C3 dominated. Furthermore, agricultural production involving C3 plants such as wheat, rice, and temperate pasture species might not increase with the rising CO2 concentration. It is also likely that introduced plant species, many of which are C4 plants, will increase in vigor and become an even greater problem than they are now. Finally, ecosystems in which C3 and C4 species grow together are likely to change as the competitive balance alters, with consequences for forage supply and its nutritional quality (5). Increased growth rates of C4 species are even more likely in the future because of global warming; the efficiency of C3 photosynthesis declines with increasing temperature, but this does not occur in C4 plants, making them more competitive in warmer conditions (9).Reich et al. were only able to make their discoveries because their experiment ran uninterrupted for two decades. This is extremely rare globally, showing that funding for long-term global-change experiments is a necessity. The experiment relied on a concerted effort to continually apply for funding, given the largely short-term nature of funding cycles. Because most funding agencies place a value on innovation and novelty, scientists are forced to come up with new reasons and new measurements to keep existing experiments running. The tenacity of Reich et al. and their ability to keep their experiment running has overturned existing theory and should lead to changes in how we think about and prepare for Earth's future. Who knows how many processes remain undiscovered because of the unwillingness of funding agencies to support long-term experiments?References1. P. B. Reich, S. E. Hobbie, T. D. Lee, M. A. Pastore, Science 360, 317 (2018).2. M. D. Hatch, C. R. Slack, Biochem. J. 101, 103 (1966).3. R. F. Sage, M. Stata, J. Plant Physiol. 172, 104 (2015).4. R. F. Sage, J. Exp. Bot. 68, e11 (2017).5. D. A. Wedin, in Warm-Season (C4) Grasses, L. E. Moser, B. L. Burson, L. E. Sollenberger, Eds. (American Society of Agronomy, Madison, WI, 2004), vol. 45, pp. 15–50.6. L. G. Holm, D. L. Plucknett, J. B. Pancho, J. P. Herberger, The World's Worst Weeds: Distribution and Biology (Univ. Press of Hawaii, Honolulu, 1977).7. D. Lüthi et al., Nature 453, 379 (2008).8. R. E. McMurtrie et al., Funct. Plant Biol. 35, 521 (2008).9. R. F. Sage, D. S. Kubien, Photosyn. Res. 77, 209 (2003).Hu, P., Yang, F., Wang, W., Xu, C., Zhang, R., Hu, Y., Xi, B., 2018. Thermal anomaly profiles inferred from fluid inclusions near extensional and strike-slip faults of the Liaodong Bay Subbasin, Bohai Bay Basin, China: Implications for fluid flow and the petroleum system. Marine and Petroleum Geology 93, 520-538. types of faulting may greatly impact the flow of hot fluids and related thermal anomalies, which may substantially affect the migration and accumulation of petroleum. However, little is known about the effects of fault types. In this study, 64 core samples were collected from localities controlled by extensional and strike-slip faults in the Liaodong Bay Subbasin, Bohai Bay Basin, and fluid inclusions in these samples were used as thermal indicators of paleo-fluids. The results show strong thermal anomalies near the extensional and strike-slip faults due to the flow of hot fluids. The highest anomalies were recorded at localities proximal to the faults: 134.4?°C at a distance of 375?m from an extensional fault and 145.5?°C at a distance of 262.5?m from the strike-slip fault. However, these anomalies are all local and decrease with increasing distance from the faults, up to a maximum distance of approximately 3000?m. Compared with those near the strike-slip fault, the anomalies near the extensional faults decrease more slowly and typically exhibit higher anomalies at similar distances, which indicates that the extensional faults are better pathways for the flow of hot fluids. The thermal effects of hot fluids have enhanced the maturation of organic matter and shifted the threshold depth for petroleum generation upward by approximately 300?m. Such effects on source rock maturation decrease with increasing distance from the faults, up to a maximum distance of approximately 3000?m. Most Ro values near the extensional faults are clearly higher than those near the strike-slip fault. Thus, the extensional faults play a more efficient role in the enhancement of source rock maturation and are interpreted as preferential pathways for the migration of generated hydrocarbons in the Liaodong Bay Subbasin.Hu, Q., Liu, H., Li, M., Li, Z., Yang, R., Zhang, Y., Sun, M., 2018. Wettability, pore connectivity and fluid-tracer migration in shale oil reservoirs of Paleogene Shahejie Formation in Dongying sag of Bohai Bay Basin, East China. Acta Petrolei Sinica 39, 278-289. systematical research is conducted on the wettability, pore connectivity and fluid-tracer mingration of typical (massive, laminated and bedded) calcareous shale samples of Shahejie Formation in Dongying depression, Jiyang sag, Bohai Bay Basin. Shale oil reservoirs have strong oil-wetting and weak water-wetting characteristics, and the μm-nm pore systems are closely related to unique mixed wettability. For these reasons, both polar and non-polar tracers are developed with different molecular sizes and reactivities, and applied in the experiments of capillary imbibition (distilled water and the anemone containing tracer) and diffusion (the brine containing tracer). After experiments, the samples are treated using laser ablation-inductively coupled plasma-mass spectrometry, so as to detect the distribution behavious and migration rates of tracers in mixed wettability shale. The research results show that a unique "dual-pathway" migration characteristics are present to shale in 3D space. First, due to weak water-wetting characteristics, the transportability of hydrophilic pore system with pore-throat diameter greater than 10 nm is very limited, and nonabsorbing tracers have a low effective diffusion coeffieicnt of 10-13-10-12m2/s and a high geometrical tortuosity of 9.24±3.20. Sencondly, the hydrophobic pore system with the pore-throat diameter of about 5 nm is characterized by rapid transportation, but the fluid migration is significantly influenced by blocking effect of the molecules with different sizes.Hu, T., Pang, X., Jiang, S., Wang, Q., Xu, T., Lu, K., Huang, C., Chen, Y., Zheng, X., 2018. Impact of paleosalinity, dilution, redox, and paleoproductivity on organic matter enrichment in a saline lacustrine rift basin: A case study of paleogene organic-rich shale in Dongpu Depression, Bohai Bay Basin, eastern China. Energy & Fuels 32, 5045-5061., lacustrine rift basins (SLRBs) can contain very productive shale oil plays, in which “sweet spots” are closely related to organic-rich shale intervals. However, organic matter enrichment in the shale intervals within SLRBs and the controlling factors have not been well-explored in past research. In this study, well Pu6-65 within the Dongpu Depression of the Bohai Bay Basin was systematically cored and analyzed for basic geochemistry, trace elements, clay mineral content, and original total organic carbon (TOC) to understand the relationships between TOC and paleosalinity, dilution, redox, and paleoproductivity. Results indicate that the Es3U and Es3L (upper and lower third member of the Paleogene Shahejie Formation) in the Dongpu Depression mainly developed in a brackish and weak anoxic to anoxic depositional environment, in which surface water featured relatively low paleoproductivity. In comparison, the dilution degree is stronger in the Es3L shale. Paleosalinity, dilution, redox, and paleoproductivity together controlled the organic matter enrichment in the Es3U and Es3L shales, while the paleosalinity, dilution, and redox condition were much more significant controlling factors than the paleoproductivity. The degree of organic matter enrichment first increases and then tends to decrease with increasing paleosalinity; the enrichment degree gradually decreases with the increasing of the dilution degree and increases with the increasing of the anoxia degree. Therefore, future exploration of organic-rich shales in the Dongpu Depression should target shale intervals developed in the environment of moderate salinity, weak dilution, and strong reducibility. This study not only improves the theory of the organic matter enrichment but also provides guidance for predicting the organic-rich shale distribution in the Dongpu Depression and in other SLRBs around the world.Hu, W., Day, D.A., Campuzano-Jost, P., Nault, B.A., Park, T., Lee, T., Croteau, P., Canagaratna, M.R., Jayne, J.T., Worsnop, D.R., Jimenez, J.L., 2018. Evaluation of the new capture vaporizer for aerosol mass spectrometers (AMS): Elemental composition and source apportionment of organic aerosols (OA). ACS Earth and Space Chemistry 2, 410-421. reduce the quantification uncertainty of commercial aerosol mass spectrometers (AMS) and aerosol chemical speciation monitors (ACSM), a new capture vaporizer (CV) was recently built to replace the standard vaporizer (SV). A collection efficiency (CE) ～ 1 in the CV AMS/ACSM has been demonstrated for ambient aerosols, but the CV also leads to increased thermal decomposition of the analytes because of longer residence time and vaporizer surface contact. This study reports on the performance of the CV for analyzing organic aerosol (OA) elemental composition and source apportionment, using both HR-ToF-AMS and ACSM for the first time. The methodology for obtaining elemental ratios from AMS spectra is updated to account for differences in OA fragmentation between the CV and SV. An artifact CO+ signal is observed for some chemically reduced laboratory compounds. If that signal is included in elemental analysis, the O:C is substantial overestimated, while accurate results are observed if the anomalous CO+ is ignored. The estimated uncertainty of O:C (H:C) of standard organic species with the CV-AMS is 23% (18%). Consistent time series of positive matrix factorization (PMF) factors and their fractions of total OA were found across the CV and SV in the three very different ambient data sets ranging from biogenic- to anthropogenic-dominated, indicating limited loss of source determination information despite the increased fragmentation. In some cases, bootstrap analysis of CV data sets shows higher uncertainty for the apportionment of total oxygenated OA (OOA) into different subtypes than that of the SV data set, which is potentially due to lower signal-to-noise at larger m/z from the increased thermal decomposition in the CV.Huang, X., Pancost, R.D., Xue, J., Gu, Y., Evershed, R.P., Xie, S., 2018. Response of carbon cycle to drier conditions in the mid-Holocene in central China. Nature Communications 9, Article 1369. nature and extent to which hydrological changes induced by the Asian summer monsoon affected key biogeochemical processes remain poorly defined. This study explores the relationship between peatland drying and carbon cycling on centennial timescales in central China using lipid biomarkers. The difference between peat n-alkane δ2H and a nearby stalagmite δ18O record reveals that intervals of prominent peatland drying occurred during the mid-Holocene. Synchronous with these drier conditions, leaf wax δ13C values show large negative excursions, with the utilization of CO2 respired from the peatland subsurface for plant photosynthesis being a possible mechanism. Crucially, successive drying events appear to have had a cumulative impact on the susceptibility of peat carbon stores to climate change. Concurrently, bacterially derived hopane δ13C values suggest the occurrence of enhanced methane oxidation during the drier periods. Collectively, these observations expand our understanding of how respiration and degradation of peat are enhanced during drying events.Hug, L.A., Co, R., 2018. It takes a village: Microbial communities thrive through interactions and metabolic handoffs. mSystems 3, DOI: 10.1128/mSystems.00152-17. enduring theme in microbial ecology is the interdependence of microbial community members. Interactions between community members include provision of cofactors, establishment of redox gradients, and turnover of key nutrients to drive biogeochemical cycles. Pathways canonically conducted by isolated organisms in laboratory cultures are instead collective products of diverse and interchangeable microbes in the environment. Current sequence-based methods provide unprecedented access to uncultivated microorganisms, allowing prediction of previously cryptic roles in biogeochemical cycles and interactions within communities. A renewed focus on cultivation-based methods is required to test predictions derived from environmental sequence data sets and to address the exponential increase in genes lacking predicted functions. Characterization of enriched microbial consortia to annotate hypothetical proteins and identify previously unknown microbial functions can fundamentally change our understanding of biogeochemical cycles. As we gain understanding of microbial processes and interactions, our capacity to harness microbial activities to address anthropogenic impacts increases.Hussain, S., van Leeuwen, J., Aryal, R., Sarkar, B., Chow, C.W.K., Beecham, S., 2018. Removal of organic matter from reservoir water: mechanisms underpinning surface chemistry of natural adsorbents. International Journal of Environmental Science and Technology 15, 847-862. of the key challenges in water treatment industry is the removal of organic compounds by cost-effective methods. This study evaluated the adsorptive removal of dissolved organic carbon (DOC) from reservoir water using fuller’s earth (FE) in comparison with natural (SQ) and modified quartz (MSQ) sands. The removal capacities of FE at different contact times, pH levels, adsorbent dosages and initial DOC concentrations were compared with both the quartz sands. The optimum DOC removals by FE and SQs were achieved at contact time of 60 and 30?min, pH level of 6 and 4, and at adsorbent dose of 1.5?g/150?mL and 10?g/100?mL, respectively. The adsorption capacity of FE (1.05?mg/g) was much higher compared to the MSQ (0.04?mg/g) and SQ (0.01?mg/g). Adsorption equilibrium data better fitted to the Freundlich model than to the Langmuir model, suggesting that adsorption occurred primarily through multilayer formation onto the surfaces of FE and SQ. The pseudo-second-order model described the uptake kinetics more effectively than the pseudo-first-order and intra-particle diffusion models, indicating that the mechanism was primarily governed by chemisorption. These observations were well supported by the physiochemical characteristics and charge behaviour of the adsorbents. In mass-transfer study, the results of liquid film diffusion model showed that the adsorption of DOC on FE was not controlled by film diffusion, but other mechanisms also played an essential role. This study demonstrates that FE is an effective adsorbent for the removal of DOC in surface water treatment.Ibrahim, H.M.M., 2018. Characterization of biosurfactants produced by novel strains of Ochrobactrum anthropi HM-1 and Citrobacter freundii HM-2 from used engine oil-contaminated soil. Egyptian Journal of Petroleum 27, 21-29. surfactants are widely used for industrial, agricultural, food, cosmetics, pharmaceutical, and medical applications. In this study, two bacterial strains namely, Ochrobactrum anthropi HM-1 and Citrobacter freundii HM-2, previously isolated from used engine oil contaminated soil, and capable of producing biosurfactants, were used. Their cell-free culture broth showed positive results toward five screening tests (hemolysis in blood agar, drop collapse, oil displacement, emulsification activity (E24), and surface tension (ST) reduction). They reduced the ST of growth medium (70 ± 0.9) to 30.8 ± 0.6 and 32.5 ± 1.3 mN/m, respectively. The biosurfactants were classified as anionic biomolecules. Based on TLC pattern and FT-IR analysis, they were designated as glycolipids (rhamnolipid). Waste frying oil was feasibly used as a cheap and dominant carbon source for biosurfactants production; 4.9 and 4.1 g/l were obtained after 96 h of incubation, respectively. Compared with non-irradiated cells, gamma-irradiated cells (1.5 kGy) revealed enhanced biosurfactant production by 56 and 49% for HM-1 and HM-2, respectively. The biosurfactants showed good stability after exposure to extreme conditions [temperatures (50–100 °C for 30 min), pH (2–12) and salinity (2–10% NaCl)], they retained 83 and 79.3% of their E24, respectively, after incubation for a month, under extreme conditions. Biosurfactants effectively recovered up to 70 and 67% of the residual oil, respectively, from oil-saturated sand pack columns. These biosurfactants are an interesting biotechnological product for many environmental and industrial applications.Idei, S., Honda, T., Lu, R., Miyakoshi, T., 2018. Analysis of Sakhalin-Ainu lacquerwares by pyrolysis gas chromatography/mass spectrometry. Journal of Archaeological Science: Reports 20, 1-5. pieces of Sakhalin-Ainu lacquerware were analyzed by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) to determine the lacquer source. In the direct Py-GC/MS, 3-heptylphenol (P7) and 3-pentadecylphenol (P15) were detected in the mass chromatograms at m/z?=?108, and palmitic acid and stearic acid were detected at m/z?=?60 in the mass chromatograms of all pieces of Sakhalin-Ainu lacquerware, implying that drying oil was added to sap collected from a Toxicodendron vernicifluum lacquer tree to prepare the lacquer. The energy dispersive X-ray fluorescence results showed that the component ratio of base ground powder was similar to that of Aizu and Joboji lacquerwares, and the Fourier transform infrared spectroscopy results showed that Sakhalin-Ainu lacquerwares used persimmon tannin in the base ground powder like Joboji lacquerwares, suggesting that Sakhalin-Ainu lacquerwares were produced in Joboji, Japan. Based on these results, the production district, history, and culture of the Sakhalin-Ainu lacquerwares are discussed.Ivarsson, M., Bengtson, S., Drake, H., Francis, W., 2018. Fungi in deep subsurface environments, in: Sariaslani, S., Gadd, G.M. (Eds.), Advances in Applied Microbiology. Academic Press, pp. 83-116. igneous crust of the oceans and the continents represents the major part of Earth's lithosphere and has recently been recognized as a substantial, yet underexplored, microbial habitat. While prokaryotes have been the focus of most investigations, microeukaryotes have been surprisingly neglected. However, recent work acknowledges eukaryotes, and in particular fungi, as common inhabitants of the deep biosphere, including the deep igneous provinces. The fossil record of the subseafloor igneous crust, and to some extent the continental bedrock, establishes fungi or fungus-like organisms as inhabitants of deep rock since at least the Paleoproterozoic, which challenges the present notion of early fungal evolution. Additionally, deep fungi have been shown to play an important ecological role engaging in symbiosis-like relationships with prokaryotes, decomposing organic matter, and being responsible for mineral weathering and formation, thus mediating mobilization of biogeochemically important elements. In this review, we aim at covering the abundance and diversity of fungi in the various igneous rock provinces on Earth as well as describing the ecological impact of deep fungi. We further discuss what consequences recent findings might have for the understanding of the fungal distribution in extensive anoxic environments and for early fungal evolution.Izmalkova, T.Y., Gafarov, A.B., Sazonova, O.I., Sokolov, S.L., Kosheleva, I.A., Boronin, A.M., 2018. Diversity of oil-degrading microorganisms in the Gulf of Finland (Baltic Sea) in spring and in summer. Microbiology 87, 261-271. of the oil-degrading microbial strains isolated from the water and sediments of the Gulf of Finland (Baltic Sea) in winter and in summer was studied. Substrate specificity of the isolates for aliphatic and aromatic hydrocarbons was studied. The isolates belonged to 32 genera of the types Proteobacteria (alpha-, beta-, and gammaproteobacteria), Actinobacteria, Firmicutes, and Bacteroidetes. Seasonal variations of the oil-degrading microbial communities was revealed. The presence of the known genes responsible for the degradation of oil aliphatic and aromatic hydrocarbons was determined. The alkB sequence of the alkane hydroxylase gene was found in ~16% of the studied strains. The sequence of the phnAc phenanthrene 3,4- dioxygenase was found in Sphingobacterium sp. and Arthrobacter sp. isolates retrieved in winter and summer. In five Pseudomonas sp. strains from winter samples, the classical operons of naphthalene degradation (nah) were localized in catabolic plasmids, of which three belonged to IncР-9, one, to IncР-7, and two to an unidentified incompatibility group. Burkholderia and Delftia strains contained the operons for naphthalene degradation via salicylate and gentisate (nag). The presence of nag genes has not been previously reported for Delftia spp. strains. The sequences of the nagG salicylate 5-hydroxylase gene were also found in Achromobacter, Sphingobacterium, and Stenotrophomonas strains. Original Russian Text ? T.Yu. Izmalkova, A.B. Gafarov, O.I. Sazonova, S.L. Sokolov, I.A. Kosheleva, A.M. Boronin, 2018, published in Mikrobiologiya, 2018, Vol. 87, No. 2, pp. 204–216.Jayananda, M., Santosh, M., Aadhiseshan, K.R., 2018. Formation of Archean (3600–2500?Ma) continental crust in the Dharwar Craton, southern India. Earth-Science Reviews 181, 12-42. generation, preservation and destruction of continental crust on Earth is of wide interest in understanding the formation of continents, cratons and supercontinents as well as related mineral deposits. In this contribution, we integrate the available field, petrographic, geochronologic, elemental Nd-Hf-Pb isotope data for greenstones, TTG gneisses, sanukitoids and anatectic granites from the Dharwar Craton (southern India). This review allows us to evaluate the accretionary processes of juvenile crust, mechanisms of continental growth, and secular evolution of geodynamic processes through the 3600–2500?Ma window, hence providing important insights into building of continents in the Early Earth. The Dharwar Craton formed by assembly of micro-blocks with independent thermal records and accretionary histories. The craton can be divided into three crustal blocks (western, central and eastern) separated by major shear zones. The western block contains some of the oldest basement rocks with two generations of volcano-sedimentary greenstone sequences and discrete potassic plutons whereas the central block consist of older migmatitic TTGs, abundant younger transitional TTGs, remnants of ancient high grade supracrustal rocks, linear volcanic-dominated greenstone belts, voluminous calc-alkaline granitoids of sanukitoid affinity and anatectic granites. In contrast, the eastern block comprises younger transitional TTGs, abundant diatexites, thin volcanic-sedimentary greenstone belts and calc-alkaline plutons. Published geochronologic data show five major periods of felsic crust formation at ca. 3450–3300?Ma, 3230–3150?Ma, 3000–2960?Ma, 2700–2600?Ma, and 2560–2520?Ma which are sub-contemporaneous with the episodes of greenstone volcanism. U-Pb ages of inherited zircons in TTGs, as well as detrital zircons together with Nd-Pb-Hf isotope data, reveal continental records of 3800–3600?Ma. The U-Pb zircon data suggest at least four major reworking events during ca. 3200?Ma, 3000?Ma, 2620–2600?Ma, and 2530–2500?Ma corresponding to lower crustal melting and spatially linked high grade metamorphic events. The TTGs are sub-divided into the older (3450–3000?Ma) TTGs and the younger (2700–2600?Ma) transitional TTGs. The older TTGs can be further sub-divided into low-Al and high-Al groups. Elemental and isotopic data suggest that the low-Al type formed by melting of oceanic island arc crust within plagioclase stability field. In contrast, the elemental and isotopic features for the high-Al group suggest derivation of their magmatic precursor by melting of oceanic arc crust at deeper levels (55–65?km) with variable garnet and ilmenite in residue. The transitional TTGs likely formed by melting of composite sources involving both enriched oceanic arc crust and sub-arc mantle with minor contamination of ancient crustal components. The geochemical and isotopic compositions of granitoids with sanukitoid affinity suggest derivation from enriched mantle reservoirs. Finally, anatectic granites were produced by reworking of crustal sources with different histories. In the light of the data reviewed in this contribution, we propose the following scenario for the tectonic evolution of the Dharwar Craton. During 3450–3000?Ma, TTGs sources (oceanic arc crust) formed by melting of down going slabs and subsequent melting of such newly formed crust at different depths resulted in TTG magmas. On the contrary, by 2700?Ma the depth of slab melting increased. Melting of slab at greater depth alongside the detritus results in enriched melts partly modified the overlying mantle wedge. Subsequent melting of such newly formed enriched oceanic arc crust and surrounding arc-mantle generated the magmatic precursor to transitional TTGs. Finally at ca. 2600–2560?Ma, eventual breakoff of down going slab caused mantle upwelling which induced low degree (10–15%) melting of overlying enriched mantle at different depths, thereby, generating the sanukitoid magmas which upon emplacement into the crust caused igh temperature metamorphism, reworking and final cratonization. The crustal accretion patterns in the Dharwar Craton share similarities with those in other Archean cratons such as the Bundelkhand Craton in Central India, Pilbara-Yilgarn Craton in Western Australia, Southern Africa (Swaziland and Limpopo belt), North China Craton, Tanzania Craton, Antongil Craton, NE Madagascar.Jenniskens, P., Popova, O., 2018. Comets in the path of Earth. Elements 14, 107-112.'s atmosphere offers little protection against comet impacts, because many comets are bigger than 1 km. Fewer comets hit Earth than asteroids of the same size, except perhaps for sizes larger than 10 km. Comets release copious amounts of solid debris called meteoroids, and these meteoroids disperse to form meteoroid streams, some of which cause meteor showers on Earth. Recent meteor shower observations reveal the presence of potentially dangerous parent comets and trace their dynamical evolution. In addition, some showers leave a signature of “cosmic dust” in our atmosphere.Jian, W., Albrecht, M., Lehmann, B., Mao, J., Horn, I., Li, Y., Ye, H., Li, Z., Fang, G., Xue, Y., 2018. UV-fs-LA-ICP-MS analysis of CO2-rich fluid inclusions in a frozen state: Example from the Dahu Au-Mo deposit, Xiaoqinling region, central China. Geofluids 2018, Article 3692180. recently developed technique of ultraviolet femtosecond laser ablation inductively coupled plasma mass spectrometry (UV-fs-LA-ICP-MS) combined with a freezing cell is expected to improve the analysis of CO2-rich fluid inclusions by decreasing their internal pressure and avoiding the common problem of uncontrolled explosive fluid release on ablation. Here, we report the application of this technique through the case study of CO2-rich fluid inclusions from the quartz vein-style Au-Mo deposit of Dahu in the Xiaoqinling region of central China. The concentrations of Li, B, Na, Al, K, Ca, Mn, Fe, Cu, Zn, Rb, Sr, Mo, Ag, Te, Cs, Ba, Au, Pb, and Bi were analyzed in 124 (not all for Al and Ca) fluid inclusions, which have low to moderate salinity and multiphase composition (liquid H2O + liquid CO2??± vapor CO2??± solids). The Dahu fluids are dominated by Na and K. The concentrations of Mo are always below the detection limit from 0.005 to 2?ppm (excluding values obtained from fluid inclusions with accidentally trapped solids). The Dahu ore fluids differ from metamorphic fluids in compositions and most likely represent two separate pulses of spent fluids evolved from an unexposed and oxidized magmatic system. The UV-fs-LA-ICP-MS analysis of fluid inclusions in a frozen state improves the overpressure problem of CO2-rich fluid inclusions during laser ablation. The transformation of gaseous and liquid CO2 into the solid state leads to a significant decline in the internal pressure of the fluid inclusions, while femtosecond laser pulses generate a minimal heat input in the sample and thus maintain the frozen state during ablation. Transient signals of CO2-rich fluid inclusions obtained in this study typically had one or multiple peaks lasting for more than 15 seconds, without an initial short signal spike as obtained by ns-LA-ICP-MS analysis of CO2-rich fluid inclusions at room temperature.Jiang, K., Lin, C., Zhang, X., Cai, C., Xiao, F., He, W., Peng, L., 2018. Variations in abundance and distribution of methyltrimethyltridecylchromans (MTTCs) in sediments from saline lacustrine settings in Cenozoic lacustrine basins, China. Organic Geochemistry 121, 58-67. study examines the abundance and distribution of MTTCs and biomarker compositions in samples of MTTC-rich sediments obtained from Paleogene strata in the Bohai Bay, Jianghan and Western Qaidam Basins in China. Biomarker signatures, including high C35/C34 hopane ratios, high gammacerane index values, low pristane/phytane (Pr/Ph) ratios and the presence of aryl isoprenoids, indicate saline lacustrine settings and photic zone euxinia (PZE). The distributions of MTTCs indicate significant palaeosalinity differences in the depositional environments of the three sets of samples obtained from the Bohai Bay, Jianghan and Western Qaidam Basins. These sets of samples were deposited under normal to mesosaline, meso- to hypersaline and hypersaline environments, respectively. The δ-MTTC% values are positively correlated with the values of the gammacerane index, but are negatively correlated with the Pr/Ph ratios. This result demonstrates that MTTCs do not form in the upper or lower parts of stratified water columns, but may form in the euxinic portions of photic zones. Therefore, MTTC parameters can only be used to reconstruct palaeosalinity in the euxinic portions of photic zones and are not applicable to the upper or lower parts of stratified water columns. This paper infers that variations in palaeosalinity in the euxinic portions of photic zones likely play a key role in controlling the distribution and abundance of MTTCs.Jiang, M., Kulsing, C., Marriott, P.J., 2018. Comprehensive 2D gas chromatography–time-of-flight mass spectrometry with 2D retention indices for analysis of volatile compounds in frankincense (Boswellia papyrifera). Analytical and Bioanalytical Chemistry 410, 3185-3196. gum resin secreted from Boswellia papyrifera was analysed by comprehensive 2D gas chromatography hyphenated with accurate mass time-of-flight mass spectrometry (GC×GC?accTOFMS). Direct multiple injection experiments with stepwise isothermal temperature programming were then performed to construct isovolatility curves for reference alkane series in GC×GC. This provides access to calculation of second dimensional retention indices (2I). More than 500 peaks were detected and 220 compounds mainly comprising monoterpenes, sesquiterpenes, diterpenes and oxygenated forms of these compounds were identified according to their 1I, 2I and accurate mass data. The study demonstrates the capability of GC×GC?accTOFMS with retention data on two separate column phases, as an approach for improved component identification. A greater number of identified and/or tentatively identified terpenoids in this traditional Chinese medicine allow for a more comprehensive coverage of the volatile composition of frankincense.Jiao, Y., Wang, L., Zhang, L., An, W., Wang, W., Zhou, W., Tadé, M.O., Shao, Z., Bai, J., Li, S.-D., 2018. Direct operation of solid oxide fuel cells on low-concentration oxygen-bearing coal-bed methane with high stability. Energy & Fuels 32, 4547-4558. paper studies the electrochemical feasibility of the direct conversion of low-concentration, oxygen-bearing coal-bed methane (CBM, 30 vol?% CH4) to electricity via solid oxide fuel cells (SOFCs). A fuel cell with the LiLaNi–Al2O3/Cu catalyst layer was developed, and a maximum power output of ～1068 mW cm–2 was achieved at 850 °C using 30 vol?% CBM fuel, which is only modestly lower than that from a cell based on hydrogen fuel. The stability test showed that the cell operation was quite stable during the 120-h test period, which is ～40-fold longer than that of the cell without catalyst layer. The partial oxidation of methane (POM) occurring in the anode may play an important role when using 30 vol?% CBM fuel, which not only supplies highly active gaseous fuels (H2 and CO) but also suppresses the carbon deposition on the anode. By modifying the anode with a LiLaNi–Al2O3/Cu catalyst layer, the POM of 30 vol?% CBM was further promoted and the carbon deposition over the anode was mitigated more efficiently. Therefore, the strategy of direct conversion of low-concentration, oxygen-bearing CBM via the SOFCs with an anode catalyst layer may pave an alternative way to utilize this abundant resource efficiently and cleanly.Jin, G., Lei, H., Xu, T., Xin, X., Yuan, Y., Xia, Y., Juo, J., 2018. Simulated geomechanical responses to marine methane hydrate recovery using horizontal wells in the Shenhu area, South China Sea. Marine and Petroleum Geology 92, 424-436. recovery of natural gas hydrate (NGH) from marine sediments faces challenging due to not only the gas productivity itself but also the possible geohazards, such as seafloor subsidence, submarine landslide, wellbore instability and possible sand production. The coupled thermal-hydrodynamic-mechanical (THM) processes during NGH recovery are generally complex, and numerical simulation tools are needed to assess related geomechanical responses. We have extended the Biot consolidation model in our previous simulator TOUGH2Biot, and incorporated into the existing TOUGH?+?hydrate code, resulting in a THM simulator for the NGH recovery. The THM simulator is used to assess the geomechanical responses to gas recovery from an unconfined hydrate-bearing sediment (HBS) in the Shenhu area, South China Sea. We investigated depressurization using constant bottom-hole pressure through a horizontal well. Results show that methane production quickly reaches a stabilized state and the water rate increases linearly. The drawdown of pore pressure around the well controls the increase in effective stress. Subsidence becomes significant after depressurization due to the quickly propagation of pore pressure. Depressurization in early stage could contribute to more than half of the total subsidence. The decreasing production pressure leads to an increase in the methane production rate but deterioration in subsidence. A decrease in intrinsic permeability of overlying and underlying layer is undesirable due to its decrease in methane production rate and the worse of subsidence. A balance between gas productivity and related geomechanical response must be achieved. The methods and preliminary results presented in this study could help us to understand the geomechanical behaviors during NGH recovery and to design trial production schemes under similar conditions.John, S.G., Helgoe, J., Townsend, E., 2018. Biogeochemical cycling of Zn and Cd and their stable isotopes in the Eastern Tropical South Pacific. Marine Chemistry 201, 256-262. distribution of Zn and Cd and their stable isotope ratios (δ66Zn and δ114Cd) were measured on samples from the Eastern Subtropical South Pacific Zonal Transect (EPZT), US GEOTRACES section GP16. The broad trends in both δ66Zn and δ114Cd are similar to those observed in other ocean basins, suggesting global similarities in the biogeochemical processes which cycle Zn and Cd. For example, average deep ocean δ66Zn along this transect (+ 0.46‰) are similar to the ~+0.5‰ values observed in the deep North Atlantic and North Pacific. Also similar to other locations, δ66Zn decreases towards the surface ocean. A plume of hydrothermal Zn emanating from the East Pacific Rise is used to calculate hydrothermal end-member δ66Zn as + 0.24‰, which is similar to crustal values and similar to other sources of Zn to the oceans. Average deep-ocean δ114Cd along this transect is + 0.28‰, which is similar to deep-ocean values between + 0.2 and + 0.3 measured elsewhere in the Atlantic, Pacific, and Southern Oceans. δ114Cd increases towards the surface ocean, as observed in other ocean basins, reflecting the preferential biological uptake of lighter Cd isotopes. Elsewhere it has been hypothesized that Cd can precipitate in sulfidic microenvironments on sinking particles, affecting seawate Cd concentrations and isotope ratios. However, we don't find evidence of particularly strong CdS precipitation along this transect, despite the fact that the Peru OMZ is one of the most reducing ocean environments worldwide.John, S.G., Helgoe, J., Townsend, E., Weber, T., DeVries, T., Tagliabue, A., Moore, K., Lam, P., Marsay, C.M., Till, C., 2018. Biogeochemical cycling of Fe and Fe stable isotopes in the Eastern Tropical South Pacific. Marine Chemistry 201, 66-76. basin-scale distributions of iron (Fe) and Fe isotopes provide important insights into the biogeochemical cycling of this growth-limiting micronutrient in the ocean. Here we present new observations of dissolved Fe concentrations and stable isotope ratios (δ56Fe) from the US GEOTRACES Eastern Pacific Zonal Transect GP16. The western portion of the transect is characterized by low dissolved Fe concentrations with a heavy δ56Fe signature of + 0.4 to + 0.6‰, similar to the dust-influenced North Atlantic deep waters. This is punctuated by Fe inputs from hydrothermal vents along the East Pacific Rise, with a δ56Fe of ? 0.3‰. One striking feature of the transect is a large plume of high dissolved Fe and low δ56Fe (0 to ? 0.5‰) in the east, near the Peru margin. Here, maximum dissolved Fe occurs between 1000 and 3000 m and the elevated concentrations persist over 1000 km from the margin. The region of markedly lower δ56Fe extends even further, to roughly 4000 km offshore. The mid-slope depth at which this plume occurs (1000–3000 m) is at odds with current conceptual and numerical models of Fe inputs along continental margins, which predict a shallower and more restricted dissolved Fe maximum (upper-slope; ~ 100–1000 m). Here, we explore four possible explanations for the mid-slope Fe plume: (1) Fe fluxes are actually higher from mid-slope sediments; (2) the mid-slope plume is transported from a remote region (3) mid-slope Fe originates from resuspended sediments in a very persistent form, which remains in the dissolved phase for longer than Fe released from the upper-slope; (4) Fe is supplied from upper-slope sediments, and then transferred to greater depth by reversible scavenging onto sinking particles. Simple modeling is used to show that both input of persistent Fe from mid-slope sediments and reversible scavenging could explain the data. Flux of a more persistent chemical form of Fe from the mid-slope would be consistent with other tracers such as particle composition and 228Ra, which suggest that lithogenic sediments are preferentially resuspended at this depth, but may be at odds with the low δ56Fe signature. Reversible scavenging is consistent with both Fe concentrations and δ56Fe. Whatever its provenance, the plume observed near the Peru margin impacts Fe concentrations and δ56Fe throughout the entire eastern South Pacific region, suggesting that the roles of persistent Fe input and reversible scavenging should be appraised in fully coupled iron-carbon cycle models in order to better understand the global cycling of Fe and δ56Fe.Johnson, D.B., Beddows, P.A., Flynn, T.M., Osburn, M.R., 2018. Microbial diversity and biomarker analysis of modern freshwater microbialites from Laguna Bacalar, Mexico. Geobiology 16, 319-337. Bacalar is a sulfate‐rich freshwater lake on the Yucatan Peninsula that hosts large microbialites. High sulfate concentrations distinguish Laguna Bacalar from other freshwater microbialite sites such as Pavilion Lake and Alchichica, Mexico, as well as from other aqueous features on the Yucatan Peninsula. While cyanobacterial populations have been described here previously, this study offers a more complete characterization of the microbial populations and corresponding biogeochemical cycling using a three‐pronged geobiological approach of microscopy, high‐throughput DNA sequencing, and lipid biomarker analyses. We identify and compare diverse microbial communities of Alphaproteobacteria, Deltaproteobacteria, and Gammaproteobacteria that vary with location along a bank‐to‐bank transect across the lake, within microbialites, and within a neighboring mangrove root agglomeration. In particular, sulfate‐reducing bacteria are extremely common and diverse, constituting 7%–19% of phylogenetic diversity within the microbialites, and are hypothesized to significantly influence carbonate precipitation. In contrast, Cyanobacteria account for less than 1% of phylogenetic diversity. The distribution of lipid biomarkers reflects these changes in microbial ecology, providing meaningful biosignatures for the microbes in this system. Polysaturated short‐chain fatty acids characteristic of cyanobacteria account for <3% of total abundance in Laguna Bacalar microbialites. By contrast, even short‐chain and monounsaturated short‐chain fatty acids attributable to both Cyanobacteria and many other organisms including types of Alphaproteobacteria and Gammaproteobacteria constitute 43%–69% and 17%–25%, respectively, of total abundance in microbialites. While cyanobacteria are the largest and most visible microbes within these microbialites and dominate the mangrove root agglomeration, it is clear that their smaller, metabolically diverse associates are responsible for significant biogeochemical cycling in this microbialite system. Johnson, R.E., Sundqvist, B.U.R., 2018. Sputtering and detection of large organic molecules from Europa. Icarus 309, 338-344. spectroscopy of bio-molecules by heavy ion induced sputtering, which became a practical laboratory procedure, was also suggested as a potential tool for spacecraft studies of targets of interest in astrobiology. With the planning of new missions to Europa, there is renewed interest in the possibility of detecting organic molecules that might have originated in its subsurface ocean and can be sputtered from its surface often intact by impacting energetic heavy ions trapped in Jupiter's magnetosphere. Here we review the laboratory data and modeling bearing on this issue. We then give estimates of the ejection into the gas-phase of trace organic species embedded in an ice matrix on Europa's surface and their possible detection during a flyby mission.Johnston, S.E., Shorina, N., Bulygina, E., Vorobjeva, T., Chupakova, A., Klimov Sergey, I., Kellerman, A.M., Guillemette, F., Shiklomanov, A., Podgorski, D.C., Spencer, R.G.M., 2018. Flux and seasonality of dissolved organic matter from the northern Dvina (Severnaya Dvina) River, Russia. Journal of Geophysical Research: Biogeosciences 123, 1041-1056.‐Arctic riverine dissolved organic carbon (DOC) fluxes represent a major transfer of carbon from land‐to‐ocean, and past scaling estimates have been predominantly derived from the six major Arctic rivers. However, smaller watersheds are constrained to northern high‐latitude regions and, particularly with respect to the Eurasian Arctic, have received little attention. In this study, we evaluated the concentration of DOC and composition of dissolved organic matter (DOM) via optical parameters, biomarkers (lignin phenols), and ultrahigh resolution mass spectrometry in the Northern Dvina River (a midsized high‐latitude constrained river). Elevated DOC, lignin concentrations, and aromatic DOM indicators were observed throughout the year in comparison to the major Arctic rivers with seasonality exhibiting a clear spring freshet and also some years a secondary pulse in the autumn concurrent with the onset of freezing. Chromophoric DOM absorbance at a350 was strongly correlated to DOC and lignin across the hydrograph; however, the relationships did not fit previous models derived from the six major Arctic rivers. Updated DOC and lignin fluxes were derived for the pan‐Arctic watershed by scaling from the Northern Dvina resulting in increased DOC and lignin fluxes (50 Tg yr?1 and 216 Gg yr?1, respectively) compared to past estimates. This leads to a reduction in the residence time for terrestrial carbon in the Arctic Ocean (0.5 to 1.8 years). These findings suggest that constrained northern high‐latitude rivers are underrepresented in models of fluxes based from the six largest Arctic rivers with important ramifications for the export and fate of terrestrial carbon in the Arctic Ocean.Jones, A.C., Hambright, K.D., Caron, D.A., 2018. Ecological patterns among bacteria and microbial eukaryotes derived from network analyses in a low-salinity lake. Microbial Ecology 75, 917-929. communities are comprised of complex assemblages of highly interactive taxa. We employed network analyses to identify and describe microbial interactions and co-occurrence patterns between microbial eukaryotes and bacteria at two locations within a low salinity (0.5–3.5?ppt) lake over an annual cycle. We previously documented that the microbial diversity and community composition within Lake Texoma, southwest USA, were significantly affected by both seasonal forces and a site-specific bloom of the harmful alga, Prymnesium parvum. We used network analyses to answer ecological questions involving both the bacterial and microbial eukaryotic datasets and to infer ecological relationships within the microbial communities. Patterns of connectivity at both locations reflected the seasonality of the lake including a large rain disturbance in May, while a comparison of the communities between locations revealed a localized response to the algal bloom. A network built from shared nodes (microbial operational taxonomic units and environmental variables) and correlations identified conserved associations at both locations within the lake. Using network analyses, we were able to detect disturbance events, characterize the ecological extent of a harmful algal bloom, and infer ecological relationships not apparent from diversity statistics alone.Jongejans, L.L., Strauss, J., Lenz, J., Peterse, F., Mangelsdorf, K., Fuchs, M., Grosse, G., 2018. Organic carbon characteristics in yedoma and thermokarst deposits on Baldwin Peninsula, West-Alaska. Biogeosciences Discussions 2018, 1-29. Arctic warming continues and permafrost thaws, more soil and sedimentary organic carbon (OC) will be decomposed in northern high latitudes. Still, uncertainties remain in the quantity and quality of OC stored in different deposit types of permafrost landscapes. This study presents OC data from deep permafrost and lake deposits on the Baldwin Peninsula which is located in the southern portion of the continuous permafrost zone in West Alaska. Sediment samples from yedoma and drained thermokarst lake basin (DTLB) deposits as well as thermokarst lake sediments were analyzed for cryostratigraphical and biogeochemical parameters and their lipid biomarker composition to identify the size and quality of belowground OC pools in ice-rich permafrost on Baldwin Peninsula. We provide the first detailed characterization of yedoma deposits on Baldwin Peninsula. We show that three quarters of soil organic carbon in the frozen deposits of the study region (total of 68?Mt) is stored in DTLB deposits (52?Mt) and one quarter in the frozen yedoma deposits (16?Mt). The lake sediments contain a relatively small OC pool (4?Mt), but have the highest volumetric OC content (93?kg/m3) compared to the DTLB (35?kg/m3) and yedoma deposits (8?kg/m3), largely due to differences in the ground ice content. The biomarker analysis indicates that the OC in both yedoma and DTLB deposits is mainly of terrestrial origin. Nevertheless, the relatively high carbon preference index of plant leaf waxes in combination with a lack of degradation trend with depth in the yedoma deposits indicates that OC stored in yedoma is less degraded than that stored in DTLB deposits. This suggests that OC in yedoma has a higher potential for decomposition upon thaw, despite the relatively small size of this pool. These findings highlight the importance of molecular OC analysis for determining the potential future greenhouse gas emissions from thawing permafrost, especially because this area close to the discontinuous permafrost boundary is projected to thaw substantially within the 21st century.Kahru, M., Elmgren, R., Di Lorenzo, E., Savchuk, O., 2018. Unexplained interannual oscillations of cyanobacterial blooms in the Baltic Sea. Scientific Reports 8, Article 6365. oscillations in multi-species or even single species systems are well-known but have rarely been detected at the lower trophic levels in marine systems. Nitrogen fixing cyanobacteria are a major component of the Baltic Sea ecosystem and sometimes form huge surface accumulations covering most of the sea surface. By analysing a satellite-derived 39-year (1979–2017) data archive of surface cyanobacteria concentrations we have found evidence of strikingly regular interannual oscillations in cyanobacteria concentrations in the northern Baltic Sea. These oscillations have a period of ~3 years with a high-concentration year generally followed by one or two low-concentration years. Changes in abiotic factors known to influence the growth and survival of cyanobacteria could not provide an explanation for the oscillations. We therefore assume that these oscillations are intrinsic to the marine system, caused by an unknown, probably mainly biological mechanism that may be triggered by a combination of environmental factors. Interactions between different life cycle stages of cyanobacteria as well as between predator-prey or host-parasite are possible candidates for causing the oscillations.Kamalanathan, M., Xu, C., Schwehr, K., Bretherton, L., Beaver, M., Doyle, S.M., Genzer, J., Hillhouse, J., Sylvan, J.B., Santschi, P., Quigg, A., 2018. Extracellular enzyme activity profile in a chemically enhanced water accommodated fraction of surrogate oil: Toward understanding microbial activities after the Deepwater Horizon oil spill. Frontiers in Microbiology 9, 798. doi: 10.3389/fmicb.2018.00798. enzymes and extracellular polymeric substances (EPS) play a key role in overall microbial activity, growth and survival in the ocean. EPS, being amphiphilic in nature, can act as biological surfactant in an oil spill situation. Extracellular enzymes help microbes to digest and utilize fractions of organic matter, including EPS, which can stimulate growth and enhance microbial activity. These natural processes might have been altered during the 2010 Deepwater Horizon oil spill due to the presence of hydrocarbon and dispersant. This study aims to investigate the role of bacterial extracellular enzymes during exposure to hydrocarbons and dispersant. Mesocosm studies were conducted using a water accommodated fraction of oil mixed with the chemical dispersant, Corexit (CEWAF) in seawater collected from two different locations in the Gulf of Mexico and corresponding controls (no additions). Activities of five extracellular enzymes typically found in the EPS secreted by the microbial community – α- and β-glucosidase, lipase, alkaline phosphatase, leucine amino-peptidase – were measured using fluorogenic substrates in three different layers of the mesocosm tanks (surface, water column and bottom). Enhanced EPS production and extracellular enzyme activities were observed in the CEWAF treatment compared to the Control. Higher bacterial and micro-aggregate counts were also observed in the CEWAF treatment compared to Controls. Bacterial genera in the order Alteromonadaceae were the most abundant bacterial 16S rRNA amplicons recovered. Genomes of Alteromonadaceae commonly have alkaline phosphatase and leucine aminopeptidase, therefore they may contribute significantly to the measured enzyme activities. Only Alteromonadaceae and Pseudomonadaceae among bacteria detected here have higher percentage of genes for lipase. Piscirickettsiaceae was abundant; genomes from this order commonly have genes for leucine aminopeptidase. Overall, this study provides insights into the alteration to the microbial processes such as EPS and extracellular enzyme production, and to the microbial community, when exposed to the mixture of oil and dispersant.Kamari, A., Mohammadi, A.H., Ramjugernath, D., 2018. Data-driven modeling for determination of asphaltene stability condition in oil system. Petroleum Science and Technology 36, 726-731. precipitation is accounted as one of the most serious problems during oil production so that it can decrease the production of crude oil and cause the blockage of reservoir rock pores, etc. An accurate prediction of phase behaviour of asphaltene is therefore important in oil production industry. Accurate prediction of phase behaviour of asphaltene precipitation i.e. stability state of asphaltene precipitation in oilfields is greatly desirable. To this end, the applicability domains of the most important variables for the determination of the stability state of asphaltene precipitation viz. aromatic + resin and asphaltene + saturates have been specified by using decision tree (DT) algorithm. Next, adaptive neuro-fuzzy inference system (ANFIS) approach was implemented in order to determine the stability state of asphaltene precipitation using the efficient variables of aromatic + resin and asphaltene + saturates. The results obtained in the current study demonstrate that the models proposed in this study provide desirable results in estmating the stability state of asphaltene precipitation in oilfields.Kang, J., Sun, Y., Men, Y., Tian, J., Yu, Q., Yan, J., Lin, J., Liu, J., 2018. Shale gas enrichment conditions in the frontal margin of Dabashan orogenic belt, south China. Journal of Natural Gas Science and Engineering 54, 11-24. this study, we carried out a survey on organic-rich mudstones of Wufeng-Longmaxi formations in the frontal margin of Dabashan orogenic belt where geological structure is complex, aiming to investigate the shale gas enrichment condition and their major controlling factors. Methods including optical microscope observation, Scanning Electron Microscopy (SEM), organic geochemistry and tests of porosity, permeability, gas-bearing property, and Specific Surface Area have been applied in this study. Based on these comprehensive information collected from both the field and the laboratory, the general geological characteristics and distribution of organic-rich mudstones of Wufeng-Longmaxi formations are summarized. In the Late Ordovician-Early Silurian epoch, organic-rich mudstones were probably deposited in the continental shelf, with the thicknesses ranging from 31.5 to 156.4?m in the frontal margin of Dabashan orogenic belt, and the averaged value of total organic carbon in these mudstones varies from 2.43 to 5.17?wt% in different localities. Values of BET specific surface area range from 1.57 to 29.15?m2/g. Thermal maturity is high because Ro values vary from 1.20 to 2.58% in this region. The mineral composition, i.e., low clay mineral content (16.14–27.88%) and relatively high brittle mineral content (larger than 72.12%), is proper for future fracturing. Although the permeability and porosity values are relatively low, respectively 0.0001–0.0472?×?10?3μm2 and 0.36–3.51% in average, they are still higher than the lower limit of favorable condition of shale gas accumulation. Based on the shale gas evaluation and exploration experience conducted in this geologically complex area, we suggest that the shale gas generation conditions are good in the Dabashan area, but the preservation conditions are quite different from place to place in the tectonically complex area. In general, the preservation conditions are of the utmost importance for shale gas enrichment in Dabashan area. A comparison of failed to the successful cases of exploration wells in the frontal margin of Dabashan suggests that relatively stable box-shaped anticlines, like Tianba and Manyue anticlines, are beneficial for shale gas storage. Information obtained from this study can be used as a good reference for shale gas reservoir evaluation and the selection of shale gas Sweet Spots in further study of this region. Furthermore, the research conducted in this area provides useful experience for shale gas exploration in the tectonically complex region in the world.Kang, J., Zhang, B., Kang, T., 2018. Monte Carlo and molecular dynamic simulations of CH4 diffusion in kaolinite as functions of pressure and temperature. Journal of Natural Gas Science and Engineering 54, 65-71. properties of CH4 diffusion in kaolinite were first studied by molecular simulations. The influences of temperature and pressure were also investigated. The comparisons which validate the force-field and model in our paper were made between simulation and experiment. Simulation results demonstrate that adsorption behavior of methane exhibit Langmuir adsorption behavior. When the pressure is below the value of 3?MPa, the kaolinite swelling seems to be ignorable. And the surface diffusion is the dominant transport mechanism which means the CH4 diffusion diffusivity is larger, so the diffusion coefficients drastically decrease with increasing pressure in the region of P?<?3?MPa. The influence of kaolinite swelling for CH4 diffusion becomes significant when the pressure is greater than 3?MPa. This is because that the kaolinite swelling can narrow some micropores entrances as a result the configurational diffusion gradually becomes the dominant transport mechanism. The diffusion coefficient of configuration is smaller than surface diffusion coefficient, so the diffusion coefficients slowly decrease with increasing pressure in the region of 3?MPa?<?P?<?8?MPa. In the region of P?>?8?MPa, the diffusion coefficient increases as a result of the value of kaolinite swelling decrease. Both self-diffusivity and transport diffusivity increased linearly with increasing temperature. The diffusion activation energies at 1, 5, 10, 20, 30, and 40?MPa for CH4 are 19.31, 5.87, 5.15, 8.11, 10.93, and 11.79?kJ?mol?1, respectively. It is illustrated again that at higher temperature, CH4 diffusion in kaolinite micropores is faster and the diffusion activation energy as a function of pressure is opposite to the transport diffusion coefficient.Karimi, S., Saidian, M., Kazemi, H., 2018. Experimental study of the effect of aging on fluid distribution in Middle Bakken cores. Journal of Petroleum Science and Engineering 166, 1042-1054. wettability is a critical parameter when designing enhanced oil recovery (EOR) for field applications both in conventional and unconventional reservoirs. In this study, we only focused on one unconventional resource—the Bakken. Specifically, we conducted laboratory experiments in five uncleaned Middle Bakken cores with different initial fluid saturations to determine (1) where the fluids reside within the pores, and (2) the effect of aging on wettability change.The experimental protocol included hydrocarbon-saturation of three uncleaned cores with Bakken oil. The cores were aged at 180?°F and 2500 psi pressure for four weeks, and stored in crude oil for 1?year?at ambient laboratory conditions (about 12 psi and 66?°F). Synthetic brine was then used to produce oil from the aged cores by spontaneous imbibition in Amott cell. Additional oil was produced from the cores using a high-speed centrifuge.For the remaining two uncleaned cores, synthetic brine was used to saturate them, and brine was replaced with oil using a centrifuge. The cores were stored in crude oil at ambient laboratory conditions for four months; then, oil recovery from the cores was measured in Amott cell. NMR measurements were conducted on the cores after each fluid saturation/de-saturation experiment to determine the effect of aging time and temperature on the core wettability and fluid distribution in the pores. Also, porosity and permeability of cleaned twin cores were measured at several net confining stresses.The experimental results indicated that hydrocarbon-saturated cores become slightly more oil-wet than brine-saturated cores. NMR measurements indicated that brine resides in smaller pores and as a brine film on grains regardless of aging time, and the core fluids re-distributed with time indicating a strong rock-fluid interaction. Finally, the analysis of oil production indicated the preponderance of chemical osmosis over imbibition as the mechanism of oil displacement in formations with high brine salinity.Ke, C.-Y., Sun, W.-J., Li, Y.-B., Lu, G.-M., Zhang, Q.-Z., Zhang, X.-L., 2018. Microbial enhanced oil recovery in Baolige Oilfield using an indigenous facultative anaerobic strain Luteimonas huabeiensis sp. nov. Journal of Petroleum Science and Engineering 167, 160-167. facultative strain Luteimonas huabeiensis sp. nov. HB-2 isolated from Baolige Oilfield of China was examined for its growth, biosurfactant production, hydrocarbon degradation and the effects on interfacial properties of oil recovery system. Specifically, the effects on reduction of fluid surface tension and oil viscosity, and on increase in emulsification activity for crude oil were evaluated. This was attributed to the combination of the strain's activities including the production of biosurfactants (cyclic lipopeptides) and the degradation of crude oil. The produced biosurfactants can effectively reduce the interfacial tension of oil-water and viscosity of crude oil. Meanwhile, the long-chain hydrocarbons (C20-C35) of crude oil also can be degraded by bacteria resulting in the increase in shorter chain (C10-C19). These activities demonstrated the suitability of strain HB-2 for application in microbial enhanced oil recovery (MEOR). This was confirmed by a laboratory-based core column flooding evaluation, showing an average increase of 11% in oil recovery, which was followed by an oilfield test involving two water injection wells and eight oil production wells over 16 months, resulting in a remarkable increase in the average single well oil production from 0.48 ton/day (without MEOR) to 1.77 ton/day with the highest reaching 9.5 ton/day by MEOR.Keller, A.H., Kleinsteuber, S., Vogt, C., 2018. Anaerobic benzene mineralization by nitrate-reducing and sulfate-reducing microbial consortia enriched from the same site: Comparison of community composition and degradation characteristics. Microbial Ecology 75, 941-953. mineralization under nitrate-reducing conditions was successfully established in an on-site reactor continuously fed with nitrate and sulfidic, benzene-containing groundwater extracted from a contaminated aquifer. Filling material from the reactor columns was used to set up anoxic enrichment cultures in mineral medium with benzene as electron donor and sole organic carbon source and nitrate as electron acceptor. Benzene degradation characteristics and community composition under nitrate-reducing conditions were monitored and compared to those of a well-investigated benzene-mineralizing consortium enriched from the same column system under sulfate-reducing conditions. The nitrate-reducing cultures degraded benzene at a rate of 10.1 ± 1.7 μM d?1, accompanied by simultaneous reduction of nitrate to nitrite. The previously studied sulfate-reducing culture degraded benzene at similar rates. Carbon and hydrogen stable isotope enrichment factors determined for nitrate-dependent benzene degradation differed significantly from those of the sulfate-reducing culture (ΛH/C nitrate = 12 ± 3 compared to ΛH/C sulfate = 28 ± 3), indicating different benzene activation mechanisms under the two conditions. The nitrate-reducing community was mainly composed of Betaproteobacteria, Ignavibacteria, and Anaerolineae. Azoarcus and a phylotype related to clone Dok59 (Rhodocyclaceae) were the dominant genera, indicating an involvement in nitrate-dependent benzene degradation. The primary benzene degrader of the sulfate-reducing consortium, a phylotype belonging to the Peptococcaceae, was absent in the nitrate-reducing consortium.Kerfeld, C.A., Aussignargues, C., Zarzycki, J., Cai, F., Sutter, M., 2018. Bacterial microcompartments. Nature Reviews Microbiology 16, 277-290. microcompartments (BMCs) are self-assembling organelles that consist of an enzymatic core that is encapsulated by a selectively permeable protein shell. The potential to form BMCs is widespread and found across the kingdom Bacteria. BMCs have crucial roles in carbon dioxide fixation in autotrophs and the catabolism of organic substrates in heterotrophs. They contribute to the metabolic versatility of bacteria, providing a competitive advantage in specific environmental niches. Although BMCs were first visualized more than 60 years ago, it is mainly in the past decade that progress has been made in understanding their metabolic diversity and the structural basis of their assembly and function. This progress has not only heightened our understanding of their role in microbial metabolism but is also beginning to enable their use in a variety of applications in synthetic biology. In this Review, we focus on recent insights into the structure, assembly, diversity and function of BMCs.Kibria, M.G., Hu, Q., Liu, H., Zhang, Y., Kang, J., 2018. Pore structure, wettability, and spontaneous imbibition of Woodford Shale, Permian Basin, West Texas. Marine and Petroleum Geology 91, 735-748. after more than 30 years of exploration and production, low total recovery of shale gas (<30%) and tight oil (5%–10%) constrains sustainable shale hydrocarbon development in the United States. Since the Woodford Shale is one of the principal source rocks of the Permian Basin, West Texas, this study uses core samples of Woodford Shale from the Reliance Triple Crown (RTC) #1 well in Pecos County, Texas, to examine mineralogy, pore structure, wetting characteristics, imbibition behavior, and edge-accessible porosity with the following complementary tests: X-ray diffraction (XRD), mercury injection capillary pressure (MICP), contact angle measurement of various fluids, fluid imbibition into initially-dry shale, and edge-accessible pore connectivity from vacuum saturation-high pressure impregnation with tracers-containing n-decane. The wettability and imbibition tests use both polar (hydrophilic, deionized water) and nonpolar (hydrophobic, n-decane) fluids. Our results indicate that Woodford Shale samples (Upper, Middle, and Lower Members) have different geologic (mineralogy) and reservoir (e.g., total organic carbon, porosity, and permeability) characteristics. MICP analyses show that the median pore-throat diameters for the Woodford Shale are 3.7–5.4?nm, and almost 70–80% of pore-throats by volume are smaller than 100?nm, with high tortuosity for fluid flow and mass movement. Spontaneous fluid imbibition into Woodford Shale exhibits imbibition slopes (from the plots of log imbibition vs. log time) close to ? for deionized water and ? for n-decane, consistent with contact angle measurements that indicate a marginally water-wet, but very strong oil-wet, nature for these shales. Edge-accessible pore connectivity tests indicate that well-connected hydrophobic pore networks (primarily organic matter-hosted pores) have pore-throat sizes of approximately 5?nm and experience molecular entanglement with nm-sized tracers used in vacuum saturation tests. Our analyses suggest that the middle Woodford member will be the best interval for stimulation and hydrocarbon production. The findings from these complementary experimental approaches suggest low connectivity of tortuous nanopore networks and mixed-wet characteristics, which could have implications for total hydrocarbon recovery in Woodford Shale.Killian Galván, V.A., 2018. Models for paleodietary research: Three case-studies from arid and semi-arid environments in Northwest Argentina. Journal of Archaeological Science: Reports 18, 608-616. this article, we present three case-studies of paleodietary reconstruction from Prehispanic agropastoralist societies located in the arid and semi-arid zones of North western Argentina. These three examples include the micro-region of Antofagasta de la Sierra, located in the puna of the Catamarca Province; the puna archaeological site of Río Doncellas; and the pre-puna archaeological site of Los Amarillos. These latter two sites are situated in the Jujuy Province. Here we present a quantitative approximation that provides a relative hierarchy of plant versus animal resource consumption. In so doing, we aim to overcome the uncertainty generated by previous studies on this theme. To this end, we employed the mixed Baysian model FRUITS (Food Reconstruction Using Isotopic Transferred Signals), which utilises three different proxies – δ13Ccollagen, δ13Capatite and δ15N. This model confirmed the importance of maize vis-à-vis other resources at Los Amarillos, its lesser relevance within the Antofagasta de la Sierra context, and its negligible presence at the Río Doncellas site. Likewise, within the resource hierarchy of the puna economy – Solanum tuberosum – a seemingly, marginal crop, in contrast to camelids, gained greater traction. In this manner, we can detect the different nutritional strategies employed by the Prehispanic agropastoralist economies of the region.Kim, H.-J., Han, S.H., Kim, S., Yun, S.-T., Jun, S.-C., Oh, Y.-Y., Son, Y., 2018. Characterizing the spatial distribution of CO2 leakage from the shallow CO2 release experiment in South Korea. International Journal of Greenhouse Gas Control 72, 152-162. study was conducted to detect and characterize potential CO2 leakage from the K-COSEM shallow CO2 release experiment. The study site was established in Eumseong, South Korea, and consisted of five zones divided into two lines (east and west). Approximately 1.8?t CO2 was injected from the perforated release well at Zones 1–4 from June 1–30, 2016. CO2 fluxes varied due to the uneven permeability of soil, and CO2 leakage at the surface was detected within small area (<10?m across). In-soil CO2 concentrations within 5?m from the well were also significantly higher than those measured at 10?m from the well. These results confirmed that the spatial distribution of in-soil CO2 is strongly affected by soil properties and atmospheric pressure effects. Non-linear regression and CO2:O2 ratio analyses were conducted to determine whether there is a CO2 leakage. Even though maximum CO2 concentrations at some leak points were as low as the background concentration, CO2 concentration clearly increased. The CO2:O2 ratios from the CO2 release experiments were completely different from the ratios associated with the biological reaction. Those methods seem to be practical use as indicators of CO2 leakage detection.Kirkham, C., Cartwright, J., Hermanrud, C., Jebsen, C., 2018. The genesis of mud volcano conduits through thick evaporite sequences. Basin Research 30, 217-236. study documents the seismic expression of the conduits underlying over 350 mud volcanoes that were erupted in an area of the western Nile Cone in the past 5.3?Myr. The study is based on a c. 4300?km2 3D seismic survey. The conduits are interpreted to transect the >1000‐m‐thick Messinian Evaporite succession, demonstrating that the eruptive process is sufficiently dynamic to breach the formidable seal represented by the evaporites. The mud volcano conduits are remarkably similar in geometry and seismic characteristics to many previously described examples of fluid escape pipes. They are vertical to subvertical structures with a crudely cylindrical geometry, but that can either widen or narrow upwards towards their upper terminations in the mud volcano edifices. Imaging at depth within the Messinian Evaporites and pre‐evaporite successions is more uncertain, but direct sampling of mud from surface volcanoes suggests a pre‐Messinian source, confirming the seismic interpretation that they root within presalt stratigraphy. A conceptual model for the genesis of these mud volcano conduits through salt is proposed, for which hydraulic fracturing is driven by high overpressures that developed in the presalt source stratigraphy as a response to the Messinian Salinity Crisis. Dissolution and removal of evaporites resulting in fracturing and collapse via a stoping mechanism is a slow process by comparison to hydraulic fracturing but is argued to potentially contribute to conduit formation. The analysis presented here demonstrates the potential for bypassing a >1‐km‐thick unit of sealing evaporites via focused fluid and sediment mobilisation from deeper overpressured cells in other salt basins worldwide, and has significant implications for hydrocarbon exploration, CO2 sequestration and nuclear waste disposal.Kitadai, N., Nakamura, R., Yamamoto, M., Takai, K., Li, Y., Yamaguchi, A., Gilbert, A., Ueno, Y., Yoshida, N., Oono, Y., 2018. Geoelectrochemical CO production: Implications for the autotrophic origin of life. Science Advances 4, Article eaao7265.’s proposal of the autotrophic origin of life theory and subsequent laboratory demonstrations of relevant organic reactions have opened a new gate for the exploration of the origin of life. However, this scenario remains controversial because, at present, it requires a high pressure of CO as a source of carbon and reducing energy, although CO must have been a trace C species on the Hadean Earth. We show that, simulating a geoelectrochemical environment in deep-sea hydrothermal fields, CO production with up to ~40% Faraday efficiency was attainable on CdS in CO2-saturated NaCl solution at ≤–1 V (versus the standard hydrogen electrode). The threshold potential is readily generated in the H2-rich, high-temperature, and alkaline hydrothermal vents that were probably widespread on the early komatiitic and basaltic ocean crust. Thus, W?chtersh?user’s scenario starting from CO2 was likely to be realized in the Hadean ocean hydrothermal systems.Knies, J., Daszinnies, M., Plaza-Faverola, A., Chand, S., Sylta, ?., Bünz, S., Johnson, J.E., Mattingsdal, R., Mienert, J., 2018. Modelling persistent methane seepage offshore western Svalbard since early Pleistocene. Marine and Petroleum Geology 91, 800-811. observations of extensive methane release into the oceans and atmosphere have raised concern as to whether rising temperatures across the Arctic could drive rapid destabilization of gas hydrate reservoirs. Here, we report modelling results from hydrate-modulated methane seepage from Vestnesa Ridge, offshore western Svalbard, suggesting that continuous leakage has occurred from the seafloor since the early Pleistocene up until today. Sustained by modelled deep subsurface thermogenic sources of Miocene age, large scale hydrocarbon fluid migration started ～6 million years ago and reached the seafloor some 4 million years later. The modelling results indicate that widespread methane seepage offshore western Svalbard commenced in earnest during early Pleistocene, significantly older than late Holocene as previously reported. We propose that the onset of vertical hydrocarbon migration is the response of rapid burial of potential hydrocarbon sources induced by increased sediment deposition following the onset of Northern Hemisphere glaciations, ～2.7 million years ago. From the modelling results we propose that source rock intervals capable of generating hydrocarbons and hydrocarbon reservoirs buried kilometers deep have continuously fueled the gas hydrate system off western Svalbard for the past 2 million years. It is this hydrocarbon system that primarily controls the thermogenic methane fluxes and seepage variability at the seabed over geological times.Knoblauch, C., Beer, C., Liebner, S., Grigoriev, M.N., Pfeiffer, E.-M., 2018. Methane production as key to the greenhouse gas budget of thawing permafrost. Nature Climate Change 8, 309-312. thaw liberates frozen organic carbon, which is decomposed into carbon dioxide (CO2) and methane (CH4). The release of these greenhouse gases (GHGs) forms a positive feedback to atmospheric CO2 and CH4 concentrations and accelerates climate change. Current studies report a minor importance of CH4 production in water-saturated (anoxic) permafrost soils and a stronger permafrost carbon–climate feedback from drained (oxic) soils. Here we show through seven-year laboratory incubations that equal amounts of CO2 and CH4 are formed in thawing permafrost under anoxic conditions after stable CH4-producing microbial communities have established. Less permafrost carbon was mineralized under anoxic conditions but more CO2–carbon equivalents (CO2–Ce) were formed than under oxic conditions when the higher global warming potential (GWP) of CH4 is taken into account. A model of organic carbon decomposition, calibrated with the observed decomposition data, predicts a higher loss of permafrost carbon under oxic conditions (113?±?58?g?CO2–C?kgC?1 (kgC, kilograms of carbon)) by 2100, but a twice as high production of CO2–Ce (241?±?138?g?CO2–Ce kgC?1) under anoxic conditions. These findings challenge the view of a stronger permafrost carbon-climate feedback from drained soils and emphasize the importance of CH4 production in thawing permafrost on climate-relevant timescales.Ko, L.T., Ruppel, S.C., Loucks, R.G., Hackley, P.C., Zhang, T., Shao, D., 2018. Pore-types and pore-network evolution in Upper Devonian-Lower Mississippian Woodford and Mississippian Barnett mudstones: Insights from laboratory thermal maturation and organic petrology. International Journal of Coal Geology 190, 3-28. models from immature organic-matter (OM) -rich Barnett (0.42%Ro) and Woodford (0.49%Ro) mudstones were compared with models previously developed from low-maturity OM-lean Boquillas (Eagle Ford-equivalent) mudstones to investigate whether (1) different mineralogy (siliceous vs. calcareous) exerts different catalytic and sorption effects and influences OM-pore origin and evolution; and (2) different types of macerals show different OM pore evolution history. Laboratory gold-tube pyrolysis, scanning electron microscopy (SEM) and thin-section petrography, organic petrography, and geochemical characterization were used to investigate the role of bulk mineralogy, maceral type, and thermal maturation on OM-pore evolution. Results suggest that mineralogy has little impact on OM-pore development and evolution. Macerals, identified using both SEM (platy OM, particulate OM, organic–mineral admixtures>, Tasmanites) and organic petrology (vitrinite, inertinite, amorphous organic matter [AOM]/bituminite, telalginite [Leiosphaeridia, Tasmanites]), do affect the origin and evolution of OM pores owing to differences in chemical compositions, generation kinetics, and activation-energy distributions between Tasmanites, matrix bituminite, and other types of macerals. Leiosphaeridia and Tasmanites in Woodford mudstone samples exhibit a delay in onset and a shorter period of petroleum generation and pore development compared to the matrix bituminite in the Barnett and Woodford mudstone samples. Pre-oil solid bitumen was observed to have migrated into initial primary mineral pore networks at the bitumen generation stage in both Barnett and Woodford samples. At higher levels of thermal maturation, the volume of primary mineral pores decreases and the pore volume composed of modified mineral pores and OM pores becomes greater. Pore evolution and pore-type heterogeneity in these mudstones is a function of the initial mineral pore network, types of kerogen and macerals, and generation kinetics of individual macerals upon thermal maturation.Kochi, S., Pérez, S.A., Tessone, A., Ugan, A., Tafuri, M.A., Nye, J., Tivoli, A.M., Zangrando, A.F., 2018. δ13C and δ15N variations in terrestrial and marine foodwebs of Beagle Channel in the Holocene. Implications for human paleodietary reconstructions. Journal of Archaeological Science: Reports 18, 696-707. this article we evaluate the isotopic variability in δ13C and δ15N values of diets among maritime hunter-gatherers of the Beagle Channel (Southern Argentina). A system with two end members –marine and terrestrial resources– is not enough to describe populations with diversified subsistence strategies. Moreover, these marine hunter-gatherers are characterized as highly mobile groups whose foraging ranges comprised not only nearshore areas, but also offshore spaces.As a first step to distinguish the diversity of prey choices during the Late Holocene, and to improve the accuracy of paleodietary interpretations, we conducted stable isotope analyses on zooarchaeological collections and modern samples of shellfish and plants. We observed that δ13C and δ15N values of aquatic animals are more clustered than expected in comparison to modern ecological parameters. Terrestrial prey, such as the guanaco, showed considerable isotopic dispersion in both carbon and nitrogen. While zooarchaeological studies have identified foraging activities in offshore spaces, stable isotope analyses should use different criteria to characterize long-term dietary patterns.With this local isotopic frame of reference, we re-examined δ13Ccollagen and δ15Ncollagen measurements of seven adult individuals from the Beagle Channel. Most individuals had marine diets complemented with resources more depleted in 13C and 15N than aquatic prey. While previous interpretations stated that the complementary staple was terrestrial protein, we suggest consumption of shellfish as another possibility. Finally, plants should be reconsidered as a source depleted both in 13C and 15N for mixing models, when typically underestimated in paleodiets from subpolar environments.Kocken, I.J., Cramwinckel, M.J., Zeebe, R.E., Middelburg, J.J., Sluijs, A., 2018. The 405 kyr and 2.4 Myr eccentricity components in Cenozoic carbon isotope records. Climate of the Past Discussions 2018, 1-21. stable carbon (δ13C) and oxygen (δ18O) isotope ratios of deep-sea foraminiferal calcite co-vary with the 405?kyr eccentricity cycle, suggesting a link between orbital forcing, the climate system, and the carbon cycle. Variations in δ18O are partly forced by ice-volume changes that have mostly occurred since the Oligocene. The cyclic δ13C–δ18O co-variations are found in both ice-free and glaciated climate states, however. Consequently, there should be a mechanism that forces the δ13C cycles independently of ice-dynamics. In search of this mechanism, we simulate the response of several key components of the carbon cycle to orbital forcing in the Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir model (LOSCAR). We force the model by changing the burial of organic carbon in the ocean with various astronomical solutions and noise, and study the response of the main carbon cycle tracers. Consistent with previous work, the simulations reveal that low frequency oscillations in the forcing are preferentially amplified relative to higher frequencies. However, while oceanic δ13C mainly varies with a 405?kyr period in the model, the dynamics of dissolved inorganic carbon in the oceans and of atmospheric CO2 are dominated by the 2.4?Myr cycle of eccentricity. This implies that the total ocean and atmosphere carbon inventory is strongly influenced by carbon cycle variability that exceeds the time scale of the 405?kyr period (such as silicate weathering). To test the applicability of the model results, we assemble a long (~?22?Myr) δ13C and δ18O composite record spanning the Eocene to Miocene (34 to 12?Ma) and perform spectral analysis to assess the presence of the 2.4?Myr cycle. We find that, while the 2.4?Myr cycle appears to be overshadowed by long-term changes in the composite record, it is is present as an amplitude modulator of the 405 and 100?kyr eccentricity cycles.Koenig, M., 2018. Primitive dark-phase cycle of photosynthesis at the origin of life. Journal of Molecular Evolution 86, 167-171. phosphorylation, isomerization, and aldolisation reactions starting from glyceraldehyde have the potential to lead to the synthesis of pre-ribonucleotide polymers through a primitive form of the Calvin cycle (dark phase of photosynthesis) involving the unusual formation of phospho-nonulose phosphate and phospho-deculose phosphate, as key intermediates. These reactions involve activated phosphates which are generated from schreibersite minerals, geochemically available in Hadean times.K?k, M.V., Varfolomeev, M.A., Nurgaliev, D.K., 2018. Application of different EOR techniques for the energy and recovery of Ashal’cha oil field. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 40, 645-653. this research, utilizing the reservoir and produced oil data, different enhanced oil recovery (EOR) techniques known as in-situ combustion, CO2 flooding, and steam flooding were applied for Ashal?cha oil field in Republic of Tatarstan, Russia. For this purpose, In-Situ Combustion Predictive Model (ICPM), CO2 Miscible Flood Predictive Model (CO2PM) and Steam-flood Predictive Model (SFPM) are used. In addition to oil recovery, economic analysis of the discussed EOR applications was also conducted. By using the oil price forecast for 10 years, each EOR method is analyzed using their expenses and outcomes separately. Comparison among the EOR applications regarding the oil production, and economic feasibility was also given. Taking the reservoir and produced oil characteristics, oil production rate and economical payout time into account, it was observed that in-situ combustion is the most feasible and practical EOR method for Ashal?cha oil field.K?k, M.V., Varfolomeev, M.A., Nurgaliev, D.K., 2018. Isoconversional methods to determine the kinetics of crude oils -thermogravimetry approach. Journal of Petroleum Science and Engineering 167, 480-485. this research, kinetics of four crude oils from different origins are determined by iso-conversional methods using thermogravimetry data (TGA-DTG). The experiments were performed at three different heating rates (5-10-15?K/min) between 300 and 1200?K. Thermal characteristics of the crude oil samples such as, reaction intervals and corresponding peak and burn-out temperatures are also determined. Three different iso-conversional methods, known as Starink, Kissinger and Friedman are used in order to determine the activation energy values of the crude oil samples studied that represents the novelty of the research. Activation energy values of the crude oil samples are varied between 50 and 102?kJ/mol and 69–132?kJ/mol in low temperature oxidation region and high temperature oxidation region, respectively.Kong, F., Zhao, P., Ye, X., Wang, Z., Qin, Z., Yu, P., Su, J., Shi, F., Du, J., 2018. Nanoscale zero-field electron spin resonance spectroscopy. Nature Communications 9, article 1563. spin resonance (ESR) spectroscopy has broad applications in physics, chemistry, and biology. As a complementary tool, zero-field ESR (ZF-ESR) spectroscopy has been proposed for decades and shown its own benefits for investigating the electron fine and hyperfine interaction. However, the ZF-ESR method has been rarely used due to the low sensitivity and the requirement of much larger samples than conventional ESR. In this work, we present a method for deploying ZF-ESR spectroscopy at the nanoscale by using a highly sensitive quantum sensor, the nitrogen vacancy center in diamond. We also measure the nanoscale ZF-ESR spectrum of a few P1 centers in diamond, and show that the hyperfine coupling constant can be directly extracted from the spectrum. This method opens the door to practical applications of ZF-ESR spectroscopy, such as investigation of the structure and polarity information in spin-modified organic and biological systems.Korneev, D.S., Melenevskii, V.N., Pevneva, G.S., Golovko, A.K., 2018. Group composition of hydrocarbons and hetero compounds in stepwise-thermolysis products of asphaltenes from Usa oil. Petroleum Chemistry 58, 179-185. group composition of hydrocarbons (HC) and hetero compounds in the products of stepwise thermolysis of asphaltenes from crude oil of the Usa oilfield at temperatures of 120, 230, 370, 500 and 750°C has been studied. The volatile thermolysis products formed at each step of the process have been studied by gas chromatography–mass spectrometry. It has been found that the main products of stepwise thermolysis of asphaltene molecules are alkylbenzenes (AB) and saturated aliphatic hydrocarbons (SAH), aromatic fragments obtained at 370°C are mainly separate structural blocks of asphaltene molecules, and benzothiophenes (BT) predominate over dibenzothiophenes (DBT) as structural units of asphaltene molecules. It has been shown that with an increase in the process temperature, the alkylbenzenes/saturated aliphatic hydrocarbons ratio (AB/SAH + Alkenes) increases by a factor of 6 to 7; the phenanthrene/alkylbenzenes (PN/AB) ratio and the polycyclic aromatic hydrocarbons/alkylbenzenes (PAH/AB) ratio decrease by ten- and twofold, respectively; and the naphthalenes/alkylbenzenes (NP/AB) ratio increases by two times. Original Russian Text ? D.S. Korneev, V.N. Melenevskii, G.S. Pevneva, A.K. Golovko, 2018, published in Neftekhimiya, 2018, Vol. 58, No. 2, pp. 128–134.Koulikov, S., Assonov, S., Fajgelj, A., Tans, P., 2018. Potential improvements aimed at high precision δ13C isotopic ratio determinations in CO2 mixtures using optical absorption spectrometry. Talanta 184, 73-86. manuscript explores some advantages and limitations of laser based optical spectroscopy, aimed at achieving robust, high-reproducibility 13C16O2 and 12C16O2 ratio determinations on the VPDB-CO2 δ13C scale by measuring the absorbance of line pairs of 13C16O2 and 12C16O2. In particular, the sensitivities of spectroscopic lines to both pressure (P) and temperature (T) are discussed. Based on the considerations and estimations presented, a level of reproducibility of the 13C16O2/12C16O2 ratio determinations may be achieved of about 10?6. Thus one may establish an optical spectroscopic measurement technique for robust, high-precision 13C16O2 and 12C16O2 ratio measurements aimed at very low uncertainty. (Notably, creating such an optical instrument and developing technical solutions is beyond the scope of this paper.) The total combined uncertainty will also include the uncertainty component(s) related to the accuracy of calibration on the VPDB-CO2 δ13C scale. Addressing high-accuracy calibrations is presently not straightforward - absolute numerical values of 13C/12C for the VPDB-CO2 scale are not well known. Traditional stable isotope mass-spectrometry uses calibrations vs CO2 evolved from the primary carbonate reference materials; which can hardly be used for calibrating commercial optical stable isotope analysers. In contrast to mass-spectrometry, the major advantage of the laser-based spectrometric technique detailed in this paper is its high robustness. Therefore one can introduce a new spectrometric δ13C characterisation method which, being once well-calibrated on the VPDB-CO2 scale, may not require any further (re-)calibrations. This can be used for characterisation of δ13C in CO2–in-air mixtures with high precision and also with high accuracy. If this technique can be realised with the estimated long-term reproducibility (order of 10?6), it could potentially serve as a more convenient Optical Transfer Standard (OTS), characterising large amounts of CO2 gas mixtures on the VPDB-CO2 δ13C scale without having to compare to carbonate-evolved CO2. Furthermore, if the OTS method proves to be successful, it might be considered for re-defining the VPDB-CO2 δ13C-scale as the ratio of selected CO2 spectroscopic absorbance lines measured at pre-defined T & P conditions.The approach can also be expanded to δ18O characterisation (using 16O12C18O and 16O12C16O absorbance lines) of CO2 gas mixtures and potentially to other isotope ratios of other gases.Kozma, E.E., Webb, N.M., Harcourt-Smith, W.E.H., Raichlen, D.A., Ao?t, K., Brown, M.H., Finestone, E.M., Ross, S.R., Aerts, P., Pontzer, H., 2018. Hip extensor mechanics and the evolution of walking and climbing capabilities in humans, apes, and fossil hominins. Proceedings of the National Academy of Sciences 115, 4134-4139.: The evolution of humans’ distinct bipedal gait remains a focus of research and debate. Many reconstructions of hominin locomotor evolution assume climbing capability trades off against walking economy, with improvement in one requiring diminishment of the other, but few have tested these functional inferences experimentally. In this study, we integrate experimental locomotor mechanics from humans and other primates with osteological measurements to assess the locomotor capabilities of early hominins. Our analyses show that changes in the ischium and hamstrings would have made walking more economical without reducing the utility of these muscles for climbing in early hominins. A wider set of evolutionary solutions may have been available to early hominins than previously recognized.Abstract: The evolutionary emergence of humans’ remarkably economical walking gait remains a focus of research and debate, but experimentally validated approaches linking locomotor capability to postcranial anatomy are limited. In this study, we integrated 3D morphometrics of hominoid pelvic shape with experimental measurements of hip kinematics and kinetics during walking and climbing, hamstring activity, and passive range of hip extension in humans, apes, and other primates to assess arboreal–terrestrial trade-offs in ischium morphology among living taxa. We show that hamstring-powered hip extension during habitual walking and climbing in living apes and humans is strongly predicted, and likely constrained, by the relative length and orientation of the ischium. Ape pelves permit greater extensor moments at the hip, enhancing climbing capability, but limit their range of hip extension, resulting in a crouched gait. Human pelves reduce hip extensor moments but permit a greater degree of hip extension, which greatly improves walking economy (i.e., distance traveled/energy consumed). Applying these results to fossil pelves suggests that early hominins differed from both humans and extant apes in having an economical walking gait without sacrificing climbing capability. Ardipithecus was capable of nearly human-like hip extension during bipedal walking, but retained the capacity for powerful, ape-like hip extension during vertical climbing. Hip extension capability was essentially human-like in Australopithecus afarensis and Australopithecus africanus, suggesting an economical walking gait but reduced mechanical advantage for powered hip extension during climbing.Krissansen-Totton, J., Arney, G.N., Catling, D.C., 2018. Constraining the climate and ocean pH of the early Earth with a geological carbon cycle model. Proceedings of the National Academy of Sciences 115, 4105-4110.: The climate and ocean pH of the early Earth are important for understanding the origin and early evolution of life. However, estimates of early climate range from below freezing to over 70 °C, and ocean pH estimates span from strongly acidic to alkaline. To better constrain environmental conditions, we applied a self-consistent geological carbon cycle model to the last 4 billion years. The model predicts a temperate (0–50 °C) climate and circumneutral ocean pH throughout the Precambrian due to stabilizing feedbacks from continental and seafloor weathering. These environmental conditions under which life emerged and diversified were akin to the modern Earth. Similar stabilizing feedbacks on climate and ocean pH may operate on earthlike exoplanets, implying life elsewhere could emerge in comparable environments.Abstract: The early Earth’s environment is controversial. Climatic estimates range from hot to glacial, and inferred marine pH spans strongly alkaline to acidic. Better understanding of early climate and ocean chemistry would improve our knowledge of the origin of life and its coevolution with the environment. Here, we use a geological carbon cycle model with ocean chemistry to calculate self-consistent histories of climate and ocean pH. Our carbon cycle model includes an empirically justified temperature and pH dependence of seafloor weathering, allowing the relative importance of continental and seafloor weathering to be evaluated. We find that the Archean climate was likely temperate (0–50 °C) due to the combined negative feedbacks of continental and seafloor weathering. Ocean pH evolves monotonically from 6.6 +0.6 ?0.4 (2σ) at 4.0 Ga to 7.0 +0.7 ?0.5 (2σ) at the Archean–Proterozoic boundary, and to 7.9 +0.1 ?0.2 (2σ) at the Proterozoic–Phanerozoic boundary. This evolution is driven by the secular decline of pCO2, which in turn is a consequence of increasing solar luminosity, but is moderated by carbonate alkalinity delivered from continental and seafloor weathering. Archean seafloor weathering may have been a comparable carbon sink to continental weathering, but is less dominant than previously assumed, and would not have induced global glaciation. We show how these conclusions are robust to a wide range of scenarios for continental growth, internal heat flow evolution and outgassing history, greenhouse gas abundances, and changes in the biotic enhancement of weathering.Krukenberg, V., Riedel, D., Gruber‐Vodicka Harald, R., Buttigieg Pier, L., Tegetmeyer Halina, E., Boetius, A., Wegener, G., 2018. Gene expression and ultrastructure of meso‐ and thermophilic methanotrophic consortia. Environmental Microbiology 20, 1651-1666. sulfate‐dependent, anaerobic oxidation of methane (AOM) is an important sink for methane in marine environments. It is carried out between anaerobic methanotrophic archaea (ANME) and sulfate‐reducing bacteria (SRB) living in syntrophic partnership. In this study, we compared the genomes, gene expression patterns and ultrastructures of three phylogenetically different microbial consortia found in hydrocarbon‐rich environments under different temperature regimes: ANME‐1a/HotSeep‐1 (60°C), ANME‐1a/Seep‐SRB2 (37°C) and ANME‐2c/Seep‐SRB2 (20°C). All three ANME encode a reverse methanogenesis pathway: ANME‐2c encodes all enzymes, while ANME‐1a lacks the gene for N5,N10‐methylene tetrahydromethanopterin reductase (mer) and encodes a methylenetetrahydrofolate reductase (Met). The bacterial partners contain the genes encoding the canonical dissimilatory sulfate reduction pathway. During AOM, all three consortia types highly expressed genes encoding for the formation of flagella or type IV pili and/or c‐type cytochromes, some predicted to be extracellular. ANME‐2c expressed potentially extracellular cytochromes with up to 32 hemes, whereas ANME‐1a and SRB expressed less complex cytochromes (≤ 8 and?≤?12 heme respectively). The intercellular space of all consortia showed nanowire‐like structures and heme‐rich areas. These features are proposed to enable interspecies electron exchange, hence suggesting that direct electron transfer is a common mechanism to sulfate‐dependent AOM, and that both partners synthesize molecules to enable it. Kulongoski, J.T., McMahon, P.B., Land, M., Wright, M.T., Johnson, T.A., Landon, M.K., 2018. Origin of methane and sources of high concentrations in Los Angeles groundwater. Journal of Geophysical Research: Biogeosciences 123, 818-831.: In 2014, samples from 37 monitoring wells at 17 locations, within or near oil fields, and one site >5 km from oil fields, in the Los Angeles Basin, California, were analyzed for dissolved hydrocarbon gas isotopes and abundances. The wells sample a variety of depths of an aquifer system composed of unconsolidated and semiconsolidated sediments under various conditions of confinement. Concentrations of methane in groundwater samples ranged from 0.002 to 150 mg/L—some of the highest concentrations reported in a densely populated urban area. The δ13C and δ2H of the methane ranged from ?80.8 to ?45.5 per mil (‰) and ?249.8 to ?134.9‰, respectively, and, along with oxidation‐reduction processes, helped to identify the origin of methane as microbial methanogenesis and CO2 reduction as its main formation pathway. The distribution of methane concentrations and isotopes is consistent with the high concentrations of methane in Los Angeles Basin groundwater originating from relatively shallow microbial production in anoxic or suboxic conditions. Source of the methane is the aquifer sediments rather than the upward migration or leakage of thermogenic methane associated with oil fields in the basin. Plain Language Summary: High dissolved methane gas concentrations were measured in 37 groundwater samples collected in the Los Angeles Basin, California. The origin of the methane was identified as microbial activity rather than from the burial and heating of organic material. The source of the methane was microbial production in shallow, oxygen‐depleted aquifers rather than the upward migration or leakage of methane associated with oil fields in the basin. Kuypers, M.M.M., Marchant, H.K., Kartal, B., 2018. The microbial nitrogen-cycling network. Nature Reviews Microbiology 16, 263-276. is an essential component of all living organisms and the main nutrient limiting life on our planet. By far, the largest inventory of freely accessible nitrogen is atmospheric dinitrogen, but most organisms rely on more bioavailable forms of nitrogen, such as ammonium and nitrate, for growth. The availability of these substrates depends on diverse nitrogen-transforming reactions that are carried out by complex networks of metabolically versatile microorganisms. In this Review, we summarize our current understanding of the microbial nitrogen-cycling network, including novel processes, their underlying biochemical pathways, the involved microorganisms, their environmental importance and industrial applications.Laber, C.P., Hunter, J.E., Carvalho, F., Collins, J.R., Hunter, E.J., Schieler, B.M., Boss, E., More, K., Frada, M., Thamatrakoln, K., Brown, C.M., Haramaty, L., Ossolinski, J., Fredricks, H., Nissimov, J.I., Vandzura, R., Sheyn, U., Lehahn, Y., Chant, R.J., Martins, A.M., Coolen, M.J.L., Vardi, A., DiTullio, G.R., Van Mooy, B.A.S., Bidle, K.D., 2018. Coccolithovirus facilitation of carbon export in the North Atlantic. Nature Microbiology 3, 537-547. phytoplankton account for approximately half of global primary productivity, making their fate an important driver of the marine carbon cycle. Viruses are thought to recycle more than one-quarter of oceanic photosynthetically fixed organic carbon, which can stimulate nutrient regeneration, primary production and upper ocean respiration via lytic infection and the ‘virus shunt’. Ultimately, this limits the trophic transfer of carbon and energy to both higher food webs and the deep ocean. Using imagery taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite, along with a suite of diagnostic lipid- and gene-based molecular biomarkers, in situ optical sensors and sediment traps, we show that Coccolithovirus infections of mesoscale (~100?km) Emiliania huxleyi blooms in the North Atlantic are coupled with particle aggregation, high zooplankton grazing and greater downward vertical fluxes of both particulate organic and particulate inorganic carbon from the upper mixed layer. Our analyses captured blooms in different phases of infection (early, late and post) and revealed the highest export flux in ‘early-infected blooms’ with sinking particles being disproportionately enriched with infected cells and subsequently remineralized at depth in the mesopelagic. Our findings reveal viral infection as a previously unrecognized ecosystem process enhancing biological pump efficiency.Lai, H., Li, M., Liu, J., Mao, F., Yang, L., Yang, C., Xiao, H., 2018. Source rock types and logging evaluation in forced regressive systems tract: Taking the Termit Basin (Niger) as an example. Acta Sedimentologica Sinica 36, 390-400., petroleum geologists have paid more attention to the Forced Regressive Systems Tract (FRST) for the development of effective reservoir rocks therein, however, studies focused on potential source rocks of FRST are rare. In this paper, a combination of lithology, well logging and geochemical analysis data of Termit Basin (Niger) was used to investigate the types, well logging identification and geochemical characteristics of source rocks in FRST. Furthermore, the development of different source rocks have been preliminarily analyzed on the basis of the total organic carbon (TOC) prediction model established by an improved ΔlogR method. Results indicate that 4 types of source rocks occur in FRST:coal/coaly mudstone, shoreface mudstone, deltaic mudstone and offshore mudstone. Offshore source rocks vertically distribute in the bottom sections of FRST, and the shoreface source rocks widely occurred in FRST while the thin coal/coaly mudstone existed associating with coastal marsh and deltaic environment. Shoreface mudstones are classified as good to excellent source rocks with type Ⅱ2 kerogen and high TOC content; the deltaic mudstones consist of poor to good source rocks with higher heterogeneity than others, while the offshore source rocks are poor due to the dominance of Type Ⅲ kerogen. In this study, a TOC prediction model was established with the value of ΔlogR acquired from a plot of lgR versus Δt. TOC prediction curves from the model of different wells in Termit Basin indicate that most of FRST source rocks in different tectonic blocks have a good to excellent hydrocarbon potential, mainly consist of shoreface source rocks with larger cumulative thickness and higher hydrocarbon potential than others. Based on the evolution progress and the examples of Termit Basin, we can draw the conclusion that excellent source rocks could be occurred in the FRST, and the shoreface mudstones might be their main types of source rocks.Lai, L., Gudiyella, S., Liu, M., Green, W.H., 2018. Chemistry of alkylaromatics reconsidered. Energy & Fuels 32, 5489-5500. investigate upgrading crude oil, alkylaromatic compounds are often chosen as model compounds to better understand their reactivity. In recent kinetic models of this chemistry, the main reaction consuming the alkylaromatic is a four-membered ring “retro-ene” reaction. Here, the transition state of that reaction is discovered to be inconsistent with six-membered ring retroene reactions reported in the literature, leading to inaccurate conclusions. A new detailed kinetic model is constructed using Reaction Mechanism Generator (RMG), and thermodynamic parameters of key compounds and radicals are identified to limit model accuracy. Thermochemistry for key species in the chemistry of hexylbenzene, including hexylbenzene, alkylbenzenes, alkylbenzene radicals, aliphatic radicals, and styrene, was calculated using the CBS-QB3 quantum chemistry method to improve the accuracy of the hexylbenzene pyrolysis model. The kinetics of a key beta scission reaction were also calculated. The results of these calculations have led to an overall improvement in hexylbenzene pyrolysis model predictions.Lai, Z., Fiehn, O., 2018. Mass spectral fragmentation of trimethylsilylated small molecules. Mass Spectrometry Reviews 37, 245-257. spectrometry‐based untargeted metabolomics detects many peaks that cannot be identified. While advances have been made for automatic structure annotations in LC‐electrospray‐MS/MS, no open source solutions are available for hard electron ionization used in GC‐MS. In metabolomics, most compounds bear moieties with acidic protons, for example, amino, hydroxyl, or carboxyl groups. Such functional groups increase the boiling points of metabolites too much for use in GC‐MS. Hence, in GC‐MS‐focused metabolomics, derivatization of these groups is essential and has been employed since the 1960s. Specifically, trimethylsilylation is known as mild and universal method for GC‐MS analysis. Here, we comprehensively compile accurate mass fragmentation rules and pathways of trimethylsilylated small molecules from 80 research articles over the past 5 decades, including diagnostic fragment ions, neutral losses, and typical ion ratios, for alcohols, carboxylic acids, amines, amino acids, sugars, steroids, thiols, and phosphates. These fragmentation rules were subsequently validated by specificity and sensitivity assessments using the NIST 14 nominal mass library and a new in‐house GC‐QTOF MS library containing 589 accurate mass spectra. From 556 tested fragmentation patterns, 228 rules yielded true positive hits within 4?mDa mass accuracy. These rules can be applied to assign substructures for mass spectra computation and unknown identification.Lan, T., Yang, J., Zhang, X.-g., Hou, J.-b., 2018. A new macroalgal assemblage from the Xiaoshiba Biota (Cambrian Series 2, Stage 3) of southern China. Palaeogeography, Palaeoclimatology, Palaeoecology 499, 35-44. preserved Burgess Shale-type fossils from the Xiaoshiba Lagerst?tte in the Cambrian (Series 2) Hongjingshao Formation of southern China provide remarkable perspective on early metazoans but have never been reported with plants. Here we first recognize a new assemblage of highly mineralized macroalgae from this biota. Based on morphological differences, there are three new genera and four new species identified: Doulia rara gen. et sp. nov., Eolaminaria simigladiola sp. nov., Singulariphyca ramosa gen. et sp. nov. and Rugophyca longa gen. et sp. nov. Relative to the other three species, S. ramosa is widely distributed among the beds, which may indicate a dominat species in this community. This new discovery fills part of the long gap in the detailed record of macroalgae between the Chengjiang Biota and the Kaili Biota, representing a localized macroalgal flourish at the end of Cambrian Stage 3. The assemblage that shows morphological characters similar to some macroalgae found in the Precambrian and primitive to those of the Cambrian Stage 5 lays the basis for revealing the evolutionary biology of early macroalgae and understanding the Precambrian-Cambrian transition questions. Taphonomic study of this fossiliferous bed indicates that some well-preserved macroalgae are preserved within their original habitats. Through analyzing the depositional environments of the known Cambrian macroalgae, we suggest that macroalgae tend to be preserved in relatively deep marine environments with less disturbance.Lantos, I., Palamarczuk, V., Orgaz, M., Ratto, N., Maier, M., 2018. Exploring the culinary uses of Santa María and Belén painted vessels from the Late Intermediate Period in Catamarca, Argentina. Journal of Archaeological Science: Reports 18, 660-667. María and Belén vessels from the Late Intermediate Period (10th–15th centuries AD) in Northwest Argentina are strongly associated to funerary uses as “urns”. However, multiple recent findings of these vessels in domestic non-funerary contexts point towards diverse utilities. In this paper we carried out an exploratory analysis and selected two case studies of Santa María vessels and one of a Belén vessel, all recovered in household floors from three sites in Catamarca, Argentina. In order to enquire into the potential culinary uses of vessels, lipid residues were extracted from the ceramic matrixes and gas chromatography–mass spectrometry (GC–MS) analyses were carried out to explore their origins. In all three vessels lipid residues were recovered and characterized. Two samples showed evidence of plant and animal lipid mixtures, while the third sample only had animal lipids. The culinary utility of these vessels was confirmed, and uses may have included storage or service of liquids or stews. These preliminary results provide insight into an alternative interpretation of Santa María and Belén vessel use.Lattaud, J., Kirkels, F., Peterse, F., Freymond, C.V., Eglinton, T.I., Hefter, J., Mollenhauer, G., Balzano, S., Villanueva, L., van der Meer, M.T.J., Hopmans, E.C., Sinninghe Damsté, J.S., Schouten, S., 2018. Long-chain diols in rivers: distribution and potential biological sources. Biogeosciences Discussions 2018, 1-24. chain diols (LCDs) occur widespread in marine environments and also in lakes and rivers. Transport of LCDs from rivers may impact the distribution of LCDs in coastal environments, however relatively little is known about the distribution and biological sources of LCDs in river systems. In this study, we investigated the distribution of LCDs in suspended particulate matter (SPM) of three river systems (Godavari, Danube, and Rhine) in relation with season, precipitation, temperature, and source catchments. The dominant long-chain diol is the C32 1,15-diol followed by the C30 1,15-diol in all studied river systems. In regions influenced by marine waters, such as delta systems, the fractional abundance of the C30 1,15-diol is substantially higher than in the river itself, suggesting different LCD producers in marine and freshwater environments. A change in the LCD distribution along the downstream transects of the rivers studied was not observed. However, an effect of river flow is observed, i.e. the concentration of the C32 1,15-diol is higher in stagnant waters, such as reservoirs and during seasons with river low stands. A seasonal change in the LCD distribution was observed in the Rhine, likely due to a change in the producers. Eukaryotic diversity analysis by 18S rRNA gene sequencing of SPM from the Rhine showed extremely low abundances of sequences (i.e. <?0.32?% of total reads) related to known algal LCD producers. Furthermore, incubation of the river water with 13C-labelled bicarbonate did not result in 13C incorporation into LCDs. This indicates that the LCDs present are mainly of fossil origin in the fast flowing part of the Rhine. Overall, our results suggest that the LCD-producers in rivers predominantly reside in lakes or side ponds that are part of the river system.Lau, Y.H., Giessen, T.W., Altenburg, W.J., Silver, P.A., 2018. Prokaryotic nanocompartments form synthetic organelles in a eukaryote. Nature Communications 9, Article 1311. of proteins into organelles is a promising strategy for enhancing the productivity of engineered eukaryotic organisms. However, approaches that co-opt endogenous organelles may be limited by the potential for unwanted crosstalk and disruption of native metabolic functions. Here, we present the construction of synthetic non-endogenous organelles in the eukaryotic yeast Saccharomyces cerevisiae, based on the prokaryotic family of self-assembling proteins known as encapsulins. We establish that encapsulins self-assemble to form nanoscale compartments in yeast, and that heterologous proteins can be selectively targeted for compartmentalization. Housing destabilized proteins within encapsulin compartments afford protection against proteolytic degradation in vivo, while the interaction between split protein components is enhanced upon co-localization within the compartment interior. Furthermore, encapsulin compartments can support enzymatic catalysis, with substrate turnover observed for an encapsulated yeast enzyme. Encapsulin compartments therefore represent a modular platform, orthogonal to existing organelles, for programming synthetic compartmentalization in eukaryotes.Lavrentyeva, E.V., Radnagurueva, A.A., Barkhutova, D.D., Belkova, N.L., Zaitseva, S.V., Namsaraev, Z.B., Gorlenko, V.M., Namsaraev, B.B., 2018. Bacterial diversity and functional activity of microbial communities in hot springs of the Baikal Rift Zone. Microbiology 87, 272-281. this study the bacterial diversity of thermophilic microbial mats (40 to 65°C) in three alkaline hot springs of the Baikal Rift Zone (BRZ) was determined through pyrosequencing of 16S rRNA gene libraries. Significant diversity of bacterial species was found in the biomats of the hot springs with total number of detected phylotypes of 607. The highest share of the microbial community was represented by the phyla Chloroflexi (Seya Spring, 76.4%), Deinococcus-Thermus (Alla Spring, 45.1%), Nitrospira (Alla Spring, 36.1%), Cyanobacteria (Tsenkher Spring, 33.1%), and Proteobacteria (Tsenkher Spring, 22.6%), but their ratio varied significantly in different springs. A comparison of the biodiversity and composition of microbial communities between hot springs showed a decrease in biodiversity with increasing temperature. A large number of sequences showed a low degree of similarity with cultivated representatives in public databases. Microbial communities showed intensive rates of production and destruction of organic compounds, as revealed by the quantitative assessment of their functional activity.Lawler, A., 2018. Cannabis, opium use part of ancient Near Eastern cultures. Science 360, 249-250. as long as there has been civilization, there have been mind-altering drugs. Alcohol was distilled at least 10,000 years ago in the Fertile Crescent, about the same time that agriculture took hold there. Elsewhere, for example in Mesoamerica, other psychoactive drugs were an important part of culture. But the ancient Near East had seemed curiously drug-free—until recently.Now, new techniques for analyzing residues in excavated jars and identifying tiny amounts of plant material suggest that ancient Near Easterners indulged in a range of psychoactive substances. Recent advances in identifying traces of organic fats, waxes, and resins invisible to the eye have allowed scientists to pinpoint the presence of various substances with a degree of accuracy unthinkable a decade or two ago.For example, “hard scientific evidence” shows that ancient people extracted opium from poppies, says David Collard, senior archaeologist at Jacobs, an engineering firm in Melbourne, Australia, who found signs of ritual opium use on Cyprus dating back more than 3000 years. By then, drugs like cannabis had arrived in Mesopotamia, while people from Turkey to Egypt experimented with local substances such as blue water lily.Some senior researchers are still dubious, pointing out that ancient texts are mostly silent on such substances. Others consider the topic “unworthy of scholarly attention,” Collard says. “The archaeology of the ancient Near East is traditionally conservative.”But the work is prompting fresh thinking on the relationship between substances and societies. At the International Congress on the Archaeology of the Ancient Near East here last week, for example, one scholar even reinterpreted well-studied ancient images as representing drug-taking rituals and drug-induced distortions.Drug use almost certainly began in prehistory and spread with migrations. For example, the Yamnaya people, who swept out of Central Asia about 5000 years ago and left their genes in most living Europeans and South Asians (see p. 252), appear to have carried cannabis to Europe and the Middle East. In 2016, a team from the German Archaeological Institute and the Free University, both in Berlin, found residues and botanical remains of the plant, which originates in East and Central Asia, at Yamnaya sites across Eurasia. It's difficult to know whether the Yamnaya used cannabis simply to make hemp for rope or also smoked or ingested it. But some ancient people did inhale: Digs in the Caucasus have uncovered braziers containing seeds and charred remains of cannabis dating to about 3000 B.C.E.Once people organized into city states, they may also have started large-scale production of pharmaceuticals, says archaeologist Luca Peyronel of the International University of Languages and Media in Milan, Italy. A decade ago, before the onset of Syria's brutal civil war, he was part of a team that gathered samples from an unusual kitchen in a palace in the northwestern Syrian city of Ebla, which flourished 4 millennia ago on the outskirts of the Sumerian and Akkadian empires.The room lacked the plant and animal remains typically associated with food preparation. But residue analyses on pots found there may explain the mystery, as Peyronel and his colleagues described in a paper last year: The researchers found traces of wild plants often used for medicine, such as poppy for opium to dull pain, heliotrope to fight viral infections, and chamomile to reduce inflammation. Given that the space contained eight hearths and pots that could hold 40 to 70 liters, the drugs could have been made in large quantities, Peyronel says.Some of these extracts, such as opium, can induce hallucinations, although it's unclear whether the potions were used in ritual or medicine. The kitchen's location near the heart of the palace suggests its products were used for ceremonial occasions, and cuneiform tablets from the building mention special priests associated with ritual beverages, Peyronel says. The distinction between medicine and mind-altering drug may have been lost on ancient peoples. “The two hypotheses are not necessarily at odds,” he adds.Three hundred kilometers due west and several centuries later, the ancient people of Cyprus used opium in religious ceremonies, Collard says. Residue analyses show that between 1600 and 1000 B.C.E., people poured opium alkaloids into pots crafted in the shape of the seed capsule of the opium poppy, in what Collard calls “prehistoric commodity branding.” All the jugs were found in temples and tombs, suggesting a role in ritual. Opium jugs made on Cyprus have been found in Egypt and the Levant—the first clear example of the international drug trade.Other substances less well known today may have played a role in healing or ecstatic rituals in the ancient Near East. When King Tutankhamun's tomb, dating to the 14th century B.C.E., was opened in 1922, archaeologists found the boy-king's body covered with the flowers of blue water lily, a common motif in many Egyptian tomb paintings. Steeped in wine for several weeks, the plant yields a sedative that produces a calm euphoria.Diana Stein, an archaeologist at Birkbeck University of London, claims archaeologists have long studied scenes of rituals involving drugs and their effects without realizing it. She argues that the banquet scenes that often adorn small seals found Anatolia, Syria, Mesopotamia, and Iran actually show people imbibing psychoactive potions. Another common motif, interpreted as a scene of contest, may instead represent the internal conflict that results when the imbiber faces an alternative reality, Stein proposes. In these images, “everything is distorted and pulsing—but they certainly knew how to carve things realistically when they wanted to,” she said at the meeting here.“I find Diana's arguments convincing and even energizing, as they open up a new avenue for research,” says Megan Cifarelli, an art historian at Manhattanville College in Purchase, New York.But others are more cautious. “Scholars have tended to shy away from the possibility that the ancient Near Easterners partook of ‘recreational’ drugs, apart from alcohol, so it's good that someone is brave enough to look into it,” says archaeologist Glenn Schwartz at Johns Hopkins University in Baltimore, Maryland. But he says Stein's suggestions “seem to go too far on too little evidence,” a view echoed by many at the meeting.Collard, however, is confident that additional residue and botanical analyses, along with study of iconography and texts, will gradually persuade skeptics. Cifarelli notes that the ancients likely used drugs not just to heal, but to forge sets of beliefs, and contact a spiritual realm where healing and religion were entwined. “Most of us,” she says, “are so far removed from that kind of transformative magic.”Lawler, A., 2018. Searching for a Stone Age Odysseus. Science 360, 362., who voyaged across the wine-dark seas of the Mediterranean in Homer's epic, may have had some astonishingly ancient forerunners. A decade ago, when excavators claimed to have found stone tools on the Greek island of Crete dating back at least 130,000 years, other archaeologists were stunned—and skeptical. But since then, at that site and others, researchers have quietly built up a convincing case for Stone Age seafarers—and for the even more remarkable possibility that they were Neandertals, the extinct cousins of modern humans.The finds strongly suggest that the urge to go to sea, and the cognitive and technological means to do so, predates modern humans, says Alan Simmons, an archaeologist at the University of Nevada in Las Vegas who gave an overview of recent finds at a meeting here last week of the Society for American Archaeology. “The orthodoxy until pretty recently was that you don't have seafarers until the early Bronze Age,” adds archaeologist John Cherry of Brown University, an initial skeptic. “Now we are talking about seafaring Neandertals. It's a pretty stunning change.”Scholars long thought that the capability to construct and victual a watercraft and then navigate it to a distant coast arrived only with the advent of agriculture and animal domestication. The earliest known boat, found in the Netherlands, dates back only 10,000 years or so, and convincing evidence of sails only shows up in Egypt's Old Kingdom around 2500 B.C.E. Not until 2000 B.C.E. is there physical evidence that sailors crossed the open ocean, from India to Arabia.But a growing inventory of stone tools and the occasional bone scattered across Eurasia tells a radically different story. (Wooden boats and paddles don't typically survive the ages.) Early members of the human family such as Homo erectus are now known to have crossed several kilometers of deep water more than a million years ago in Indonesia, to islands such as Flores and Sulawesi. Modern humans braved treacherous waters to reach Australia by 65,000 years ago. But in both cases, some archaeologists say early seafarers might have embarked by accident, perhaps swept out to sea by tsunamis.In contrast, the recent evidence from the Mediterranean suggests purposeful navigation. Archaeologists had long noted ancient-looking stone tools on several Mediterranean islands including Crete, which has been an island for more than 5 million years, but they were dismissed as oddities.Then in 2008 and 2009, Thomas Strasser of Providence College in Rhode Island co-led a Greek-U.S. team with archaeologist Curtis Runnels of Boston University and discovered hundreds of stone tools near the southern coastal village of Plakias. The picks, cleavers, scrapers, and bifaces were so plentiful that a one-off accidental stranding seems unlikely, Strasser says. The tools also offered a clue to the identity of the early seafarers: The artifacts resemble Acheulean tools developed more than a million years ago by H. erectus and used until about 130,000 years ago by Neandertals as well.Strasser argued that the tools may represent a sea-borne migration of Neandertals from the Near East to Europe. The team used a variety of techniques to date the soil around the tools to at least 130,000 years old, but they could not pinpoint a more exact date. And the stratigraphy at the site is unclear, raising questions about whether the artifacts are as old as the soil they were embedded in. So other archaeologists were skeptical.But the surprise discovery prompted researchers to scour the region for additional sites, an effort that is now bearing fruit. Possible Neandertal artifacts have turned up on a number of islands, including at Stelida on the island of Naxos. Naxos sits 250 kilometers north of Crete in the Aegean Sea; even during glacial times, when sea levels were lower, it was likely accessible only by watercraft. A Greek-Canadian team co-led by Tristan Carter of McMaster University in Hamilton, Canada, uncovered hundreds of tools embedded in the soil of a chert quarry. The hand axes and blades resemble the so-called Mousterian toolkit, which Neandertals and modern humans made from about 200,000 years ago until 50,000 years ago. These tools require a more sophisticated flaking method than Acheulean types do, including preparing a stone core before striking flakes off it.Dating work on the artifacts is ongoing and Carter declined to comment pending publication. But Cherry says the Naxos evidence may be persuasive because it is well stratified, which means researchers should be able to date it more securely. “It is very convincing, because there are a lot more tools in situ,” adds Strasser, who, like Cherry, was not involved in the dig. “It is a quarry site littered with Mousterian stone tools.”Other Paleolithic tools that appear to be Mousterian have been recovered on the western Ionian islands of Kefalonia and Zakynthos. The plethora of sites adds weight to the idea of purposeful settlement. “People are going back and forth to islands much earlier than we thought,” Simmons says.But determining which of today's islands were truly islands tens of thousands of years ago isn't easy, as it depends on local land movements as well as broader sea-level changes, says Nikos Efstratiou, an archaeologist at Aristotle University of Thessaloniki in Greece. On the Aegean island of Lemnos, his team found what he thinks is a Paleolithic hunting camp dating back more than 10,000 years. But he can't yet be sure when Lemnos was cut off from the mainland. Efstratiou adds that archaeologists need to better characterize the sorts of tools made on the mainland and the islands, so they can find links between the mainland and island peoples.Other archaeologists are already reckoning with the possibility that humans and our cousins went to sea thousands of years earlier than had been thought. “We severely miscalculated,” admits Runnels, who excavated at the Crete site. If his colleagues are right, he says, “the seas were more permeable than we thought.”Laye, V.J., DasSarma, S., 2018. An Antarctic extreme halophile and its polyextremophilic enzyme: Effects of perchlorate salts. Astrobiology 18, 412-418. of perchlorate salts prevalent on the surface of Mars are of significant interest to astrobiology from the perspective of potential life on the Red Planet. Halorubrum lacusprofundi, a cold-adapted halophilic Antarctic archaeon, was able to grow anaerobically on 0.04?M concentration of perchlorate. With increasing concentrations of perchlorate, growth was inhibited, with half-maximal growth rate in ca. 0.3?M NaClO4 and 0.1?M Mg(ClO4)2 under aerobic conditions. Magnesium ions were also inhibitory for growth, but at considerably higher concentrations, with half-maximal growth rate above 1?M. For a purified halophilic β-galactosidase enzyme of H. lacusprofundi expressed in Halobacterium sp. NRC-1, 50% inhibition of catalytic activity was observed at 0.88?M NaClO4 and 0.13?M Mg(ClO4)2. Magnesium ions were a more potent inhibitor of the enzyme than of cell growth. Steady-state kinetic analysis showed that Mg(ClO4)2 acts as a mixed inhibitor (KI?=?0.04?M), with magnesium alone being a competitive inhibitor (KI?=?0.3?M) and perchlorate alone acting as a very weak noncompetitive inhibitor (KI?=?2?M). Based on the estimated concentrations of perchlorate salts on the surface of Mars, our results show that neither sodium nor magnesium perchlorates would significantly inhibit growth and enzyme activity of halophiles. This is the first study of perchlorate effects on a purified enzyme.Lebedev, A.T., Mazur, D.M., Polyakova, O.V., Kosyakov, D.S., Kozhevnikov, A.Y., Latkin, T.B., Andreeva Yu, I., Artaev, V.B., 2018. Semi volatile organic compounds in the snow of Russian Arctic islands: Archipelago Novaya Zemlya. Environmental Pollution 239, 416-427. contamination of the Arctic has widely been used as a worldwide pollution marker. Various classes of organic pollutants such as pesticides, personal care products, PAHs, flame retardants, biomass burning markers, and many others emerging contaminants have been regularly detected in Arctic samples. Although numerous papers have been published reporting data from the Canadian, Danish, and Norwegian Arctic regions, the environmental situation in Russian Arctic remains mostly underreported. Snow analysis is known to be used for monitoring air pollution in the regions with cold climate in both short-term and long-term studies. This paper presents the results of a nontargeted study on the semivolatile organic compounds detected and identified in snow samples collected at the Russian Artic Archipelago Novaya Zemlya in June 2016. Gas chromatography coupled to a high-resolution time-of-flight mass spectrometer enabled the simultaneous detection and quantification of a variety of pollutants including those from the US Environmental Protection Agency (EPA) priority pollutants list, emerging contaminants (plasticizers, flame retardants-only detection), as well as the identification of novel Arctic organic pollutants, (e.g., fatty acid amides and polyoxyalkanes). The possible sources of these novel pollutants are also discussed.GC-HRMS enabled the detection and identification of emerging contaminants and novel organic pollutants in the Arctic, e.g., fatty amides and polyoxyalkanes.Ledogar, S.H., Feranec, R.S., Zuhlke, J.M., 2018. Isotopic evidence for broad diet including anadromous fish during the mid-Holocene in northeastern North America. Journal of Archaeological Science: Reports 19, 505-512. evidence, including riverine and lake settlements, as well as fishing and netting artifacts, suggests that there was an increased reliance on inland fisheries during the mid-Holocene (ca. 4500–1800?cal BP) in northeastern North America. Unfortunately, more direct lines of evidence investigating this idea have not been thoroughly examined due to several factors, including inconsistent excavation techniques, and limitations in destructive analysis of human material remains. Here, we measured stable carbon and nitrogen isotope values from one human female and fifteen terrestrial and aquatic faunal taxa from deposits within the mid-Holocene site, Dutchess Quarry Cave 1 (Orange County, NY), to assess dietary source proportions and determine whether anadromous fish were a prominent dietary component for this individual. Using cluster analysis, potential prey species were grouped into three sources consistent with anadromous fish (“prey 1”), carnivores and omnivores (“prey 2”), and terrestrial herbivores and game birds (“prey 3”). We evaluated the relative contributions of the stable isotope values of the three prey groups using Bayesian analysis with MixSIAR. Our results indicate that animals within prey 3 made up the largest component of this individual's diet, implying that terrestrial herbivores and game birds likely dominated her diet. Fauna from isotope groups prey 1 (anadromous fish) and 2 (carnivores and omnivores) supplemented the diet. Based on these data, it appears that anadromous fish were a seasonal component of human diet and that the incorporation of these resources did not involve the dramatic reduction of other year-round protein sources.Lee, D.H., Kim, J.H., Lee, Y.M., Stadnitskaia, A., Jin, Y.K., Niemann, H., Kim, Y.G., Shin, K.H., 2018. Biogeochemical and microbiological evidence for methane-related archaeal communities at active submarine mud volcanoes on the Canadian Beaufort Sea slope. Biogeosciences Discussions 2018, 1-38. this study, we report lipid biomarker patterns and phylogenetic identities of key microbes mediating anaerobic oxidation of methane (AOM) communities in active mud volcanos (MVs) on the continental slope of the Canadian Beaufort Sea. The enriched δ13C values of total organic carbon (TOC) as well as lipid biomarkers such as archaeol and biphytanes (BPs) relative to δ13CCH4 values suggested that the contribution of AOM-related biomass to sedimentary TOC was in general negligible in the Beaufort Sea MVs investigated. However, the δ13C values of sn-2- and sn-3-hydroxyarchaeol were more negative than CH4, indicating the presence of AOM communities, albeit in a small amount. The ratio of sn-2-hydroxyarchaeol to archaeol and the 16S rRNA results indeed indicated that archaea of the ANME-2c and ANME-3 clades were involved in AOM. Further studies are needed to investigate the diversity and distribution of AOM communities and to characterize their habitats in the uppermost surface sediments of Beaufort Sea MV systems.Lee, L.L., Blumer-Schuette, S.E., Izquierdo, J.A., Zurawski, J.V., Loder, A.J., Conway, J.M., Elkins, J.G., Podar, M., Clum, A., Jones, P.C., Piatek, M.J., Weighill, D.A., Jacobson, D.A., Adams, M.W.W., Kelly, R.M., 2018. Genus-wide assessment of lignocellulose utilization in the extremely thermophilic genus Caldicellulosiruptor by genomic, pangenomic, and metagenomic analyses. Applied and Environmental Microbiology 84, Article e02694-17.: Metagenomic data from Obsidian Pool (Yellowstone National Park, USA) and 13 genome sequences were used to reassess genus-wide biodiversity for the extremely thermophilic Caldicellulosiruptor. The updated core genome contains 1,401 ortholog groups (average genome size for 13 species = 2,516 genes). The pangenome, which remains open with a revised total of 3,493 ortholog groups, encodes a variety of multidomain glycoside hydrolases (GHs). These include three cellulases with GH48 domains that are colocated in the glucan degradation locus (GDL) and are specific determinants for microcrystalline cellulose utilization. Three recently sequenced species, Caldicellulosiruptor sp. strain Rt8.B8 (renamed here Caldicellulosiruptor morganii), Thermoanaerobacter cellulolyticus strain NA10 (renamed here Caldicellulosiruptor naganoensis), and Caldicellulosiruptor sp. strain Wai35.B1 (renamed here Caldicellulosiruptor danielii), degraded Avicel and lignocellulose (switchgrass). C. morganii was more efficient than Caldicellulosiruptor bescii in this regard and differed from the other 12 species examined, both based on genome content and organization and in the specific domain features of conserved GHs. Metagenomic analysis of lignocellulose-enriched samples from Obsidian Pool revealed limited new information on genus biodiversity. Enrichments yielded genomic signatures closely related to that of Caldicellulosiruptor obsidiansis, but there was also evidence for other thermophilic fermentative anaerobes (Caldanaerobacter, Fervidobacterium, Caloramator, and Clostridium). One enrichment, containing 89.8% Caldicellulosiruptor and 9.7% Caloramator, had a capacity for switchgrass solubilization comparable to that of C. bescii. These results refine the known biodiversity of Caldicellulosiruptor and indicate that microcrystalline cellulose degradation at temperatures above 70°C, based on current information, is limited to certain members of this genus that produce GH48 domain-containing enzymes. Importance: The genus Caldicellulosiruptor contains the most thermophilic bacteria capable of lignocellulose deconstruction, which are promising candidates for consolidated bioprocessing for the production of biofuels and bio-based chemicals. The focus here is on the extant capability of this genus for plant biomass degradation and the extent to which this can be inferred from the core and pangenomes, based on analysis of 13 species and metagenomic sequence information from environmental samples. Key to microcrystalline hydrolysis is the content of the glucan degradation locus (GDL), a set of genes encoding glycoside hydrolases (GHs), several of which have GH48 and family 3 carbohydrate binding module domains, that function as primary cellulases. Resolving the relationship between the GDL and lignocellulose degradation will inform efforts to identify more prolific members of the genus and to develop metabolic engineering strategies to improve this characteristic. Lee, Y., Jeon, C.O., 2018. Paraburkholderia aromaticivorans sp. nov., an aromatic hydrocarbon-degrading bacterium, isolated from gasoline-contaminated soil. International Journal of Systematic and Evolutionary Microbiology 68, 1251-1257. Gram-stain-negative, facultatively aerobic, aromatic hydrocarbon-degrading bacterium, designated strain BN5T, was isolated from gasoline-contaminated soil. Cells were motile and slightly curved rods with a single flagellum showing catalase and oxidase activities. Growth was observed at 20–37?°C (optimum, 25–30?°C), pH 3–7 (optimum, pH 5–6) and 0–2?%?NaCl (optimum, 0?%). Ubiquinone-8 was the predominant respiratory quinone. The major fatty acids were C16?:?0, cyclo-C19?:?0 ω8c and summed feature 8 (comprising C18?:?1ω7c and/or C18?:?1ω6c). Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified phosphoamino lipid, three unidentified amino lipids and eight unidentified lipids were the identified polar lipids. The DNA G+C?content was 62.93?mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain BN5T formed a phylogenic lineage with members of the genus Paraburkholderia and showed the highest 16S rRNA gene sequence similarities to Paraburkholderia phytofirmans PsJNT (99.4?%), Paraburkholderia dipogonis DL7T (98.8?%) and Paraburkholderia insulsa PNG-AprilT (98.8?%). The average nucleotide identity and in silico DNA–DNA hybridization (DDH) values between strain BN5T and P. phytofirmans PsJNT were 88.5 and 36.5?%, respectively. The DDH values for strain BN5T with P. dipogonis LMG 28415T and P. insulsa DSM 28142T were 41.0±4.9?% (reciprocal, 33.0±4.3?%) and 47.1±6.6?% (reciprocal, 51.7±5.4?%), respectively. Based on its physiological, chemotaxonomic and phylogenetic features, we conclude that strain BN5T is a novel species of the genus Paraburkholderia , for which the name Paraburkholderia aromaticivorans sp. nov. is proposed. The type strain is BN5T (=KACC 19419T=JCM 32303T). The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene and the genome sequences of strain BN5T are MF817715 and NZ_CP022989.1–96.1, respectively.Lemordant, L., Gentine, P., Swann, A.S., Cook, B.I., Scheff, J., 2018. Critical impact of vegetation physiology on the continental hydrologic cycle in response to increasing CO2. Proceedings of the National Academy of Sciences 115, 4093-4098.: Predicting how increasing atmospheric CO2 will affect the hydrologic cycle is of utmost importance for a wide range of applications. It is typically thought that future dryness will depend on precipitation changes, i.e., change in water supply, and changes in evaporative demand due to either increased radiation or temperature. Opposite to this viewpoint, using Earth system models, we show that changes in key water-stress variables will be strongly modified by vegetation physiological effects in response to increased [CO2] at the leaf level. These results emphasize that the continental carbon and water cycles have to be studied as an interconnected system.Abstract: Predicting how increasing atmospheric CO2 will affect the hydrologic cycle is of utmost importance for a range of applications ranging from ecological services to human life and activities. A typical perspective is that hydrologic change is driven by precipitation and radiation changes due to climate change, and that the land surface will adjust. Using Earth system models with decoupled surface (vegetation physiology) and atmospheric (radiative) CO2 responses, we here show that the CO2 physiological response has a dominant role in evapotranspiration and evaporative fraction changes and has a major effect on long-term runoff compared with radiative or precipitation changes due to increased atmospheric CO2. This major effect is true for most hydrological stress variables over the largest fraction of the globe, except for soil moisture, which exhibits a more nonlinear response. This highlights the key role of vegetation in controlling future terrestrial hydrologic response and emphasizes that the carbon and water cycles are intimately coupled over land.Lengger, S.K., Sutton, P.A., Rowland, S.J., Hurley, S.J., Pearson, A., Naafs, B.D.A., Dang, X., Inglis, G.N., Pancost, R.D., 2018. Archaeal and bacterial glycerol dialkyl glycerol tetraether (GDGT) lipids in environmental samples by high temperature-gas chromatography with flame ionisation and time-of-flight mass spectrometry detection. Organic Geochemistry 121, 10-21. isoprenoidal glycerol dibiphytanyl glycerol tetraether lipids (iGDGTs) and their non-isoprenoidal branched bacterial analogues (brGDGTs) have widespread applications in biogeochemistry and paleothermometry. Analysis of GDGTs usually involves separation using high performance liquid chromatography, typically coupled via atmospheric pressure chemical ionisation to mass spectrometric detection in selected ion-monitoring mode (HPLC–APCI-MS). However, reliable determination of ratios and, in particular, quantification by this technique, can be challenging due to differences in ionisation efficiencies of the various compounds. Quantification of GDGTs also relies on external calibration of the relative response to an internal standard with authenticated GDGTs, which are often not readily accessible. Here, we tested the suitability of high temperature gas chromatography with flame ionisation detection (HTGC-FID) for the determination of concentrations and tetraether lipid-based ratios in marine and terrestrial samples. For this, we identified GDGTs in environmental samples using HTGC coupled to time-of-flight mass spectrometry (HTGC–MS). Using a purified GDGT standard, we show we can quantify GDGT-0 in environmental samples by GC-FID. Some GDGT-based ratios measured by HTGC-FID exhibited a linear correlation (1:1) with ratios derived from HPLC–MS and weight-based ratios of mixtures of purified standards. However, ratios relying on minor isomers, such as TEX86 and MBT/CBT have many unresolved challenges for determination by HTGC. Detection limits were higher than for HPLC–MS. However, the advantages of employing HTGC-based methods include: (1) the independence from MS tuning-related differences in ionisation energies; (2) the potential for direct comparison with other, non-GDGT based biomarkers; and (3) a more complete insight into biomarker distributions in environmental samples by the extension of the temperature range. Quantitative elution of GDGTs from a HTGC column as demonstrated herein, will also enable their analysis by compound-specific isotope ratio mass spectrometry.Leonova, G.A., Mal’tsev, A.E., Melenevskii, V.N., Miroshnichenko, L.V., Kondrat’eva, L.M., Bobrov, V.A., 2018. Geochemistry of diagenesis of organogenic sediments: An example of small lakes in southern West Siberia and western Baikal Area. Geochemistry International 56, 344-361. sediments (sapropels) in lakes are characterized by a reduced type of diagenesis, during which organic compounds are decomposed, the chemical composition of the pore waters is modified, and authigenic minerals (first of all, pyrite) are formed. Pyrolysis data indicate that organic matter undergoes radical transformatons already in the uppermost sapropel layers, and the composition of this organic matter is principally different from the composition of the organic matter of the its producers. The sapropels contain kerogen, whose macromolecular structure starts to develop during the very early stages of diagenesis, in the horizon of unconsolidated sediment (0–5 cm). The main role in the diagenetic transformations of organic matter in sediments is played by various physiological groups of microorganisms, first of all, heterotrophic, which amonifying, and sulfate-reducing bacteria. SO42? and Fe2+ concentrations in the pore waters of the sediments are determined to decrease (because of bacterial sulfate reduction), while concentrations of reduced Fe and S species (pyrite) in the solid phase of the sediment, conversely, increase. Comparative analysis shows that, unlike sapropels in lakes in the Baikal area, sapropels in southern West Siberia are affected by more active sulfate reduction, which can depend on both the composition of the organic matter and the SO42? concentration in the pore waters. Original Russian Text ? G.A. Leonova, A.E. Mal’tsev, V.N. Melenevskii, L.V. Miroshnichenko, L.M. Kondrat’eva, V.A. Bobrov, 2018, published in Geokhimiya, 2018, No. 4.Leorri, E., Zimmerman, A.R., Mitra, S., Christian, R.R., Fatela, F., Mallinson, D.J., 2018. Refractory organic matter in coastal salt marshes-effect on C sequestration calculations. Science of The Total Environment 633, 391-398. age and ability of salt marshes to accumulate and sequester carbon is often assessed using the carbon isotopic signatures (Δ14C and δ13C) of sedimentary organic matter. However, transfers of allochthonous refractory carbon (CRF) from the watershed to marshes would not represent new C sequestration. To better understand how refractory carbon (CRF) inputs affect assessments of marsh age and C sequestration, Δ14C and δ13C of both total organic carbon (TOC), CRF, and non-CRF organic matter fractions were measured in salt marshes from four contrasting systems on the North Atlantic coast. To our knowledge, no salt marsh sediment study has considered refractory or allochthonous carbon in carbon budget calculations or the impact on chronologies. Stable and radiogenic isotope data suggest that while TOC was dominated by autochthonous plant inputs, CRF was dominated by locally recycled or allochthonous C, the delivery of which was controlled by the size and slope of each watershed. Steep-gradient rivers analyzed delivered Δ14C-depleted CRF to their estuarine marshes, while the site located in the low-gradient river was associated with larger CRF content. Finally, the marsh isolated from riverine input contained the least fraction of TOC as CRF. Laterally transported CRF caused only a small offset in Δ14C in relation to TOC in low-gradient systems (average Δ14C offset was ?44.4 and ?24.2‰ at each location). However, the presence of allochthonous Δ14C-depleted CRF in sediments of steep-gradient rivers led to large overestimates of the time of organic matter deposition (i.e. apparent age was older than the ‘true’ time of deposition) (Δ14C offset ranged from ?170.6 to ?528.9‰). Further, reliance on TOC or loss on ignition analyses to calculate C sequestration by marshes might produce overestimates of at least as much as 10 to 20% since neither account for the lateral transport of allochthonous carbon.Levitt, N.P., Eiler, J.M., Romanek, C.S., Beard, B.L., Xu, H., Johnson, C.M., 2018. Near equilibrium 13C–18O bonding during inorganic calcite precipitation under chemo‐stat conditions. Geochemistry, Geophysics, Geosystems 19, 901-920. report results of 13C/12C, 18O/16O, and 13C?18O “clumped” isotope analyses from a series of calcite precipitation experiments from aqueous solutions under laboratory conditions. Chemo‐stat precipitation experiments were performed to synthetically form calcite from aqueous solution onto 43Ca‐labeled calcite seed crystals. Formation rate was controlled during the experiments to investigate the effect of precipitation rate and temperature on 13C?18O bonding in calcite, where rates ranged from 10?6.88 to 10?8.20 mol m?2 s?1 at three temperatures (10, 20, and 30°C). No relation was observed between precipitation rate and 13C?18O bonding proportion over the range of precipitation rates used. The relation between Δ47 and temperature produced was comparable to calibration studies which report a relatively high sensitivity of 13C?18O bonding to temperature over the range investigated. Comparing solution conditions across multiple experimental data sets indicates an inverse relation between saturation state and 13C?18O bonding, where high super‐saturation conditions are likely to be furthest from equilibrium 13C?18O partitioning. Carbon fractionation between calcite and was found to be a temperature independent value of +1.6‰. The temperature‐dependent calcite‐water 18O/16O fractionation relation determined in this study is slightly different (larger value) than those measured in several previous investigations. Significantly, we observe a dependence of the 18O/16O isotope fractionation factor on growth rate. Taken together, these findings suggest carbonate growth in our experiments approached equilibrium more closely than previous experiments of this type, yet did not achieve full O isotope equilibrium. Lewis, J.M.T., Najorka, J., Watson, J.S., Sephton, M.A., 2018. The search for hesperian organic matter on Mars: Pyrolysis studies of sediments rich in sulfur and iron. Astrobiology 18, 454-464. on Mars is of significant geological and astrobiological interest, as it forms in acidic aqueous conditions that are potentially habitable for acidophilic organisms. Jarosite can provide environmental context and may host organic matter. The most common extraction technique used to search for organic compounds on the surface of Mars is pyrolysis. However, thermal decomposition of jarosite releases oxygen into pyrolysis ovens, which degrades organic signals. Jarosite has a close association with the iron oxyhydroxide goethite in many depositional/diagenetic environments. Hematite can form by dehydration of goethite or directly from jarosite under certain aqueous conditions. Goethite and hematite are significantly more amenable than jarosite for pyrolysis experiments employed to search for organic matter. Analysis of the mineralogy and organic chemistry of samples from a natural acidic stream revealed a diverse response for organic compounds during pyrolysis of goethite-rich layers but a poor response for jarosite-rich or mixed jarosite-goethite samples. Goethite units that are associated with jarosite, but do not contain jarosite themselves, should be targeted for organic detection pyrolysis experiments on Mars. These findings are extremely timely, as exploration targets for Mars Science Laboratory include Vera Rubin Ridge (formerly known as “Hematite Ridge”), which may have formed from goethite precursors.Leyva, Y., Martín, O., García‐Jacas, C.R., 2018. Constraining the prebiotic cell size limits in extremely hostile environments: A dynamical perspective. Astrobiology 18, 403-411. ability to support a replicator population in an extremely hostile environment is considered in a simple model of a prebiotic cell. We explore from a classical approach how the replicator viability changes as a function of the cell radius. The model includes the interaction between two different species: a substrate that flows from the exterior and a replicator that feeds on the substrate and is readily destroyed in the environment outside the cell. According to our results, replicators in the cell only exist when the radius exceeds some critical value being, in general, a function of the substrate concentration, the diffusion constant of the replicator species, and the reproduction rate coefficient. Additionally, the influence of other parameters on the replicator population is also considered. The viability of chemical replicators under such drastic conditions could be crucial in understanding the origin of the first primitive cells and the ulterior development of life on our planet.Li, B., Zheng, C., Xu, J., Lv, Q., Shi, D., Li, Z., 2018. Experimental study on dynamic filtration behavior of liquid CO2 in tight sandstone. Fuel 226, 10-17. carbon dioxide (CO2) fracturing can not only enhance oil and gas production efficiently, but also realize resource utilization of CO2. Moreover, it has great potential in unconventional oil and gas exploration, as well as in carbon utilization and storage. In this study, the filtration performance of liquid CO2 in tight sandstone was studied, and the effects of CO2 temperature, pressure, thickener concentration, phase change, the oil in the formation on CO2 filtration characteristics were systematically analyzed. The results show that the viscosity is the main factor affecting the filtration rate when there is no change in the CO2 phase state. With the rise in the temperature or decline in the pressure, the viscosity of CO2 decreases and the CO2 filtration coefficient increases. Thickener added to CO2 can effectively control the filtration velocity of CO2. The filtration coefficient of CO2 with thickener decreases by one order of magnitude compared to that of pure CO2. The oil in the formation significantly lower the CO2 filtration by one order of magnitude, and it decreases with the rise of the oil viscosity. The phase change of CO2 dramatically affects the filtration. When CO2 is transforming from liquid to supercritical state in formation, the effect of two phase flow and volume expansion significantly decrease the filtration velocity. According this study, the dynamic filtration behavior of liquid CO2 in tight sandstone has been obtained. The results provide the basic data to the application of liquid CO2 fracturing and CO2 injection in CCUS.Li, D., Xu, Y., Li, Y., Wang, J., Yin, X., Ye, X., Wang, A., Wang, L., 2018. Sedimentary records of human activity and natural environmental evolution in sensitive ecosystems: A case study of a coral nature reserve in Dongshan Bay and a mangrove forest nature reserve in Zhangjiang River estuary, Southeast China. Organic Geochemistry 121, 22-35. organic carbon (TOC), total nitrogen (TN), δ13Corg, δ15N, and grain size were measured in two sediment cores from reserves adjacent to Dongshan Bay, China. The aims were to identify organic matter (OM) sources and to evaluate the combined impact of human activity and natural environmental processes over the last?～100?yr. In a coral reserve far from the estuary of Zhangjiang River, the average sediment accumulation rate (SAR) was 0.51?cm/yr from ca. 1839–2015, and the values of δ13Corg and C/N (atomic ratio of TOC to total N) ranged from ?21.9‰ to ?23.7‰ and from 5.7 to 8.1, respectively. In a mangrove forest reserve near the estuary, SAR averaged 0.49?cm/yr from ca. 1891–1985 and 2.41?cm/yr from ca. 1985–2015, and the δ13Corg and C/N values ranged from ?22.7‰ to ?26.3‰ and from 9.3 to 21.7, respectively. By combining a comparison plot of C/N and δ13Corg and a binary mixing model (based on δ13Corg and Norg/Corg, respectively), the major OM sources were assigned and their sedimentary contributions estimated. The sedimentary OM in the coral reserve had mainly an offshore marine authigenic signature with an average terrigenous contribution of <27%. In the mangrove forest reserve, the sedimentary OM was a mixture of terrestrial and marine sources, with an average terrigenous contribution of >56%. While input from the Zhangjiang River declined from the 1980?s, urban development, deforestation and land reclamation contributed to an overall increase in the total mass accumulation rate (MAR). The coral was also severely damaged by the advent of poaching around the same time. These two factors collectively resulted in a rapid decrease in OM content and OC accumulation rate (CARorg) of the sediments until the establishment of the coral reserve in 1997. Changes in terrain and climate and the construction of water conservancy facilities were traditionally the primary factors responsible for changes in the sedimentary environment of the mangrove forest reserve. Since the 1980s, however, the expansion of the mangrove forest along with human activity has led to rapid increases in MAR and CARorg; while, protective measures and a favorable climate have also promoted the growth of the mangrove forest.Li, J., Gao, Y., Jiang, H., Liu, Y., Dong, H., 2018. Pore-scale imaging of the oil cluster dynamic during drainage and imbibition using in situ X-ray microtomography. Geofluids 2018, Article 7679607. imaged water-wet and oil-wet sandstones under two-phase flow conditions for different flooding states by means of X-ray computed microtomography (μCT) with a spatial resolution of 2.1?μm/pixel. We systematically study pore-scale trapping of the nonwetting phase as well as size and distribution of its connected clusters and disconnected globules. We found a lower , 19.8%, for the oil-wet plug than for water-wet plug (25.2%). Approximate power-law distributions of the water and oil cluster sizes were observed in the pore space. Besides, the value of the wetting phase gradually decreased and the nonwetting phase gradually increased during the core-flood experiment. The remaining oil has been divided into five categories; we explored the pore fluid occupancies and studied size and distribution of the five types of trapped oil clusters during different drainage stage. The result shows that only the relative volume of the clustered oil is reduced, and the other four types of remaining oil all increased. Pore structure, wettability, and its connectivity have a significant effect on the trapped oil distribution. In the water sandstone, the trapped oil tends to occupy the center of the larger pores during the water imbibition process, leading to a stable specific surface area and a gradually decreasing oil capillary pressure. Meanwhile, in oil-wet sandstone, the trapped oil blobs that tend to occupy the pores corner and attach to the walls of the pores have a large specific surface area, and the change of the oil capillary pressure was not obvious. These results have revealed the well-known complexity of multiphase flow in rocks and preliminarily show the pore-level displacement physics of the process.Li, J., Sun, H., Liu, J.-x., Zhang, J.-j., Li, Z.-x., Fu, Y., 2018. Selective reductive cleavage of C—O bond in lignin model compounds over nitrogen-doped carbon-supported iron catalysts. Molecular Catalysis 452, 36-45. has recently attracted much attention as a promising resource to produce fuels and aromatic chemicals. The selective cleavage of C—O bond while preserving the aromatic nature has become one of the major challenges in the catalytic valorization of lignin to aromatic chemicals. In this work, we report that the selective reductive cleavage of C—O bond in lignin model compounds can be successfully achieved through heterogeneous iron catalysis. The hydrogenolysis of α-O-4 model linkage shows that the iron catalyst prepared by the simultaneous pyrolysis of iron acetate and 1,10-phenanthroline on activated carbon at 800?°C is the most active iron catalyst, affording phenol and toluene with yields of 95% and 90%, respectively. This aromatics selectivity is found to be much higher than that obtained over noble metal catalysts. The presence of N?Fe species as the active center of heterogeneous iron catalyst was confirmed by various technologies especially XPS and H2-TPR. For the β-O-4 model linkage, the vicinal —OH group was essential for the iron-catalyzed hydrogenolysis of ether linkage. The oxidation of the α-carbon in the β-O-4 model compounds can significantly decrease the bond dissociation energy of ether linkage, giving depolymerization products in moderate to excellent yields.Li, J., Wang, X., Wei, G., Yang, W., Xie, Z., Li, Z., Guo, J., Wang, Y., Ma, W., Li, J., Hao, A., 2018. New progress in basic natural gas geological theories and future exploration targets in China. Natural Gas Industry 38, 37-45. natural gas exploration expands to deep, ultra-deep and unconventional areas, more and more complex exploration targets are encountered. In this circumstance, it is necessary to improve the existing basic natural gas geological theories for guiding the exploration and discovery of more giant gas fields. In this paper, the researches on basic natural gas geological theories since the beginning of the 12th Five-Year Plan were engaged, and then the key exploration target zones were analyzed. Some results were obtained. First, the theory of whole-process hydrocarbon generation of organic matter has been improved and the geologic theories of organic matter hydrocarbon generation (e.g. the thermal evolution model of kerogen degradation and hydrocarbon generation and the successive gas generation of organic matter) have been developed. Second, multi-element natural gas genesis identification method, quantitative evaluation method for different types of seals/caprocks, tight sandstone gas accumulation theory for low hydrocarbon generation intensity region, and hydrocarbon accumulation theory for large-size ancient carbonate rock gas field have been established, and the geological theories of gas generation, genesis identification and hydrocarbon accumulation have been developed to provide the effective guidance for the exploration breakthrough and discovery of large-size gas fields in the key basins of China recently. Four conclusions were reached. First, ancient carbonate rocks, tight sandstone, foreland region, shale and volcanic rocks are primary exploration targets for discovering giant gas fields. Second, craton and foreland basins are still the key exploration areas, and paleo-uplift, gentle slope and thrust belt are the main enrichment zones. Third, ancient series of strata and deep formations are critical gas exploration targets in the future. Fourth, oil cracking gas in marine basins, tight sandstone gas and shale gas are the important replacement resources for future gas reserves and production growth.Li, L., He, Z.L., Tfaily, M.M., Inglett, P., Stoffella, P.J., 2018. Spatial-temporal variations of dissolved organic nitrogen molecular composition in agricultural runoff water. Water Research 137, 375-383. of dissolved organic nitrogen (DON) has been reported as a pathway of N loss from agriculture, but the molecular composition of DON in agricultural water is poorly understood. Runoff water samples were collected from citrus grove furrows (CGF), ditches (CGD) and pasture ditches (PD) in four seasons. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) was used to investigate molecular composition of DON. Chemodiversity index of DON had spatiotemporal variations, while the molecular composition of total DON showed minimal variations, except for PD in November. Lignin derivatives constituted 61% of the total DON compounds. Relative abundance of aliphatic compounds, char and condensed aromatics of unique DON compounds varied spatiotemporally and had a significant correlation with DON concentration. Aromaticity index decreased from CGF to connected CGD, implying that photodegradation is possibly the dominant process that alters molecular composition of aquatic DON during the transport. Significant differences in unique DON composition between CGD and PD indicates that fertilization and land use affect DON composition. The information on molecular characterization of DON should be useful for tracking DON source and developing technologies to remove DON in the agricultural runoff water.Li, M., Chen, Z., Ma, X., Cao, T., Li, Z., Jiang, Q., 2018. A numerical method for calculating total oil yield using a single routine Rock-Eval program: A case study of the Eocene Shahejie Formation in Dongying Depression, Bohai Bay Basin, China. International Journal of Coal Geology 191, 49-65. reliable total oil yield in a source rock from routine programed pyrolysis data represents a technical challenge for the characterization of source rocks in early mature and oil window due to strong interactions between bitumen and kerogen/rock matrix. A common laboratory solution for a robust estimate of total oil yield requires two pyrolysis experiments using a whole rock sample and a post-solvent extracted replicate. In this paper, we present a numerical solution that provides a reliable estimate of total oil yield directly from a single routine Rock-Eval experiment. In temperature domain, the thermally vaporized products from heavy oil and bitumen adsorbed to the organic matter and the pyrolyzed products from kerogen show a certain degree of overlap in the default temperature range of S2 peak. By transforming the routine Rock-Eval pyrogram (FID curve) into activation energy variable space, it allows for separation of the reactants into subgroups by their responses to ramping temperature. The thermally vaporized products can be then discriminated from the thermally pyrolyzed products based on the differences in their thermal stability and decomposition behaviour. The proposed method was applied to the source rock samples in the Eocene-Oligocene Shahejie Formation of Dongying Depression, Bohai Bay Basin, where programed pyrolysis results from whole rock samples and post-solvent extracted replicates were obtained. The case study suggests that (a) the two-step pyrolysis experiment approach may still under-estimate the total oil yield in case that solvent extraction treatment fails to remove all hydrocarbons in the sample; (b) the post-solvent extracted equivalent S2x values derived numerically from routine Rock-Eval analysis and those derived from post-extracted analysis are comparable with a correlation coefficient of 0.9766, suggesting numerical approach is as effective as additional laboratory experiment; and (c) the proposed approach can remove all petroleum in the sample numerically, thus providing an un-biased and robust estimate of total oil yield, a cost- and time-effective alternative to the traditional two experiment approach.Li, P., Zhang, X., Zhang, S., 2018. Structures and fractal characteristics of pores in low volatile bituminous deformed coals by low-temperature N2 adsorption after different solvents treatments. Fuel 224, 661-675. is a porous medium with fractal characteristics. With the removal of soluble fractions under solvent treatment, the structures and fractal characteristics of pores are bound to produce changes. Exampled by low volatile bituminous coals with different degrees of deformation from Huoerxinhe and Changcun coal mines in Qinshui basin, North China, the paper investigated on the changes of pore structure parameters and minerals compositions of coals before and after different solvents treatments, including tetrahydrofuran (THF), hydrochloric acid (HCl) and chlorine dioxide (ClO2). And Insight into the relationships between fractal dimensions and pore structure parameters and coal compositions were provided. Results show that: The shapes of N2 adsorption/desorption isotherms rarely change but their adsorption quantities differ sharply after different solvents treatments for coal with same deformation, indicating no change in pore type but a change in the number of pore in the same pore size. Compared to raw coals, with the removal of soluble fractions in coals pore volume (PV) and specific surface area (SSA) tend to ascend after THF extraction; changes in PV and SSA depend jointly on the dissolution of carbonate minerals and the swelling of clay minerals after HCl treatment; and the varieties of PV and SSA, to a great extent, are closely related to the swelling of clay minerals after ClO2 treatment. Pore structure fractal dimension (DA) and surface fractal dimension (DB) are obtained based on Frenkel-Halsey-Hill model. DA is mainly affected by the proportion of transitional pores and mesopores on PV; therefore, DA can be used to describe pore volumetric roughness of these transitional pores and mesopores. Meanwhile, DB is mainly influenced by the proportion of micropores on SSA; therefore, DB can be utilized to represent pore surface roughness of these micropores. As coal deformation increases, DA grows for raw coals and coals after extraction with THF; therefore, PV has a significant migration to the pores of small apertures causing the growing contribution of micropores to PV. However, DA declines for coals treated by HCl and ClO2, potentially because the welling of clay minerals blocks the pores of small apertures and increase the proportion of the pores of large apertures on PV. DB shows no clear trends with increasing coal deformation. A “reversed U-shaped” curve relationship is observed between moisture in coal and two fractal dimensions, which is due to the effect of water molecule interfacial tension. Ash correlates negatively with DA and positively with DB because of the various influences of minerals on pore homogeneity in pores of different apertures.Li, S., Tang, D., Pan, Z., Xu, H., Tao, S., Liu, Y., Ren, P., 2018. Geological conditions of deep coalbed methane in the eastern margin of the Ordos Basin, China: Implications for coalbed methane development. Journal of Natural Gas Science and Engineering 53, 394-402. coalbed methane (CBM) resource potential is enormous in China, and has become a new field for unconventional natural gas exploration and development. This work discusses the geological conditions (reservoir pressure, formation temperature and ground stress) of deep coal reservoirs in the Eastern margin of the Ordos Basin and their implication on CBM development. Various field test data of CBM wells, including injection/drawdown test data, well temperature test data, and hydraulic fracturing test data were collected from this work and literature to describe the geological conditions of the deep CBM in the study area. From the results, it is found that deep CBM in this area is characterized by high reservoir pressure, high formation temperature, and high ground stress. However, there are diverse geological particularities in the different depth range: (1) Having a wide range of pressure gradient, vast majority of coal reservoirs in the study area are under abnormally low-pressure state, which is more significant in deeper coal seams. (2) Due to the impact of surface runoff, the distribution of geothermal gradient is discrete when the burial depth is less than 700?m, and relatively concentrated when the burial depth is greater than 700?m. (3) In shallow coal reservoirs, ground stress is strongest in the horizontal direction; while in deep coal reservoirs, the strongest ground stress is in the vertical direction. Because of the complex geological conditions associated with deep burial, the balance between CBM adsorption-desorption-seepage and the rheological behavior of coal reservoirs is complex, which has significant influence on the exploration and development of deep CBM in the study area. High pressure in deep coal reservoir often leads a long inefficient desorption stage and a long draining and depressurizing process, which increases production costs. Moreover, the negative temperature effect on gas adsorption indicates that CBM content decreases with increasing depth in deep conditions, and thus the evaluation of deep CBM resources needs to be reconsidered. In addition, different stress states govern fracture patterns, and in deep environments, high ground stress greatly reduces the fracturing improvement of the coal reservoir and significantly affects the deep CBM development.Li, X., Fu, X., Yang, X., Ge, Y., Quan, F., 2018. Coalbed methane accumulation and dissipation patterns: A Case study of the Junggar Basin, NW China. Journal of Asian Earth Sciences 160, 13-26. Junggar Basin is a potential replacement area of coalbed methane (CBM) development in China. To improve the efficiency of CBM exploration, we investigated CBM accumulation and dissipation patterns of coal profiles located in the northwestern, southern, eastern, and central Junggar Basin based on the following criteria: burial depth, hydrogeological zone, CBM origin, CBM phase, and CBM migration type. We identified four types of CBM accumulation patterns: (1) a self-sourcing CBM pattern containing adsorbed gas of biogenic origin from shallow-depth coal within a weak runoff zone; (2) an endogenic migration pattern containing adsorbed gas of thermogenic origin from the medium and deep coals within a stagnant zone; (3) an exogenic migration pattern containing adsorbed gas of thermogenic origin from deep coal within a stagnant zone; and (4) an exogenic migration pattern containing adsorbed and free gas of thermogenic origin from ultra-deep coal within a stagnant zone. We also identified two types of CBM dissipation patterns: (1) shallow-depth coal within a runoff zone with mixed origin CBM; and (2) shallow and medium-deep coal seams with mixed origin CBM. CBM migration in low-rank coals was more substantial than that adsorbed in high-rank coal. CBM in shallow coal could easily escape, in the absence of closed structures or hydrogeological seals. CBM reservoirs occurred in deep coal where oversaturated gas may accumulate. Future exploration should focus on gas-water sealing structures in shallow coalbeds. CBM that occurred in adsorbed and free phases and other unconventional natural gas dominated by free gas in the coal stratum should be co-explored and co-developed.Li, Y.-B., Pu, W.-F., Wei, B., Chen, Y.-F., Bai, B.-J., 2018. The feasibility of CO2 and N2 injection for the Tahe fracture-cavity carbonate extra-heavy oil reservoir: An experimental study. Fuel 226, 598-606. Tahe Ordovician carbonate reservoir is special and unique, with its fracture and cavity serving as both pathway and crude oil storage space. Additionally, its extra-heavy crude oil is highly viscous and dense. The combination of all these characteristics leads to considerable challenges in the development of the Tahe extra-heavy oil reservoir. Due to the inelasticity of various enhanced oil recovery methods, in the study presented in this paper, CO2 and N2 were chosen as the displacing medium for the investigation of gas flooding feasibility for the Tahe carbonate extra-heavy oil reservoir. The results of physical modeling experiments showed that for Tahe crude oil, the CO2 possessed excellent solubility and viscosity reduction rate under high pressure and temperature conditions. The N2 had less influence on the extra-heavy oil than the CO2. For CO2, dissolution and extraction were the important displacement mechanisms. However, in the fracture-cavity core, high pressure caused gas breakthrough channels to form easily. The produced oil possessed better quality due to the asphaltene and resin deposition, and the CO2 was able to continue extracting light hydrocarbon along with the gas breakthrough channel. For N2, pressure maintenance was the major displacement mechanism. Due to its low solubility and extraction ability, the N2 caused gas breakthrough more easily than the CO2. The serious overlap effect reduced the gas sweep efficiency and led to the lower cumulative recovery.Li, Y.-n., Shao, L., Hou, H., Tang, Y., Yuan, Y., Zhang, J., Shang, X., Lu, J., 2018. Sequence stratigraphy, palaeogeography, and coal accumulation of the fluvio-lacustrine Middle Jurassic Xishanyao Formation in central segment of southern Junggar Basin, NW China. International Journal of Coal Geology 192, 14-38. depositional facies, sequence stratigraphy, palaeogeography, and coal accumulation in the fluvio-lacustrine Middle Jurassic Xishanyao Formation in the central Zhunnan (central segment of the southern Junggar Basin) coalfield, northwest China were analyzed based on outcrops, well cores, and geophysical well logs. Thirteen distinct lithofacies were identified ranging from conglomerate, sandstone, siltstone, mudstone, to coal. These lithofacies were grouped to five facies associations, which represent the braided fluvial, meandering fluvial, braided fluvial delta, meandering fluvial delta, and lacustrine depositional systems, respectively. Three third-order depositional sequences, S1, S2, and S3 in ascending order, were subdivided based on the erosional surfaces of incised valley fill sandstones with regional extent and the regional angular unconformities. The palaeogeographic maps of each sequence have been reconstructed based on a variety of contours of lithological parameters including the stratal thickness, coarse to fine ratios, sandstone percentages, mudstone percentages, and coal thickness. The results show that the preferred coal-forming swamps were mainly developed in the delta plain environments. The provenance includes the Yilinhabierga Mountains to the southwest and the Bogda Mountains to the southeast. Uplift of the Bogda Mountains occurred prior to S2 stage, resulting in the differentiation of the depositional environments in the west and east of the central Zhunnan coalfield. This background provided the basis for understanding the lake basin evolution and for the investigation of the controlling factors of the coal accumulation. The climatically driven lake level rise has exerted a major control on sequence stratigraphic framework under a relative stable tectonic regime. A six-period base-level change model was proposed, which evolves from LST, early TST, late TST, early HST, late HST, to FSST. The thick coals were distributed in the late TST in the landward areas in a sequence stratigraphic framework. The coal accumulation centers, represented by coal-rich zones, were located in the Huoerguosihe–Manasihe, Taxihe–Hutubihe, and Santunhe–Toutunhe areas.Li, Y., Schieber, J., Fan, T., Wei, X., 2018. Pore characterization and shale facies analysis of the Ordovician-Silurian transition of northern Guizhou, South China: The controls of shale facies on pore distribution. Marine and Petroleum Geology 92, 697-718. Ordovician-Silurian Wufeng-Longmaxi Formations in the Upper Yangtze Platform have been considered as the most promising shale play in China. However, few studies of detailed shale facies and their influence on pore distribution have been conducted. Therefore, it is important to describe the heterogeneity of shale facies in detail and elucidate their relationship to pore networks and development. Seven distinct facies were identified on the basis of their characteristic physical, biological, and chemical attributes. Ion-milled samples from all facies were examined with SEM for identification of pore types. Point-counting was used to quantify porosity. Four major pore types appear dominant: framework pores, phyllosilicate framework (PF) pores, intrapores within inorganic grains, and organic matter (OM) pores. Due to variability in composition and depositional setting of the different facies, pore networks are not uniform. Framework pores between detrital grains and PF pores are widespread in bioturbated claystones, Pores in black siliceous shales are dominated by framework pores supported by authigenic silica. Most of these are filled with kerogen/bitumen that is host to “foam” and “bubble” type OM pores. Intrapores within calcite or dolomite grains are common in fossiliferous mudstones and black dolomitic siltstones, but are isolated and do not contribute to productive porosity. In muddy siltstones, PF pores are well developed within silty bands. Initial framework pores within silty beds or laminae, however, were subsequently cemented by calcite or destroyed by compaction. As most of primary PF pores and primary frameworks pores are lost during compaction, porosity is highly dependent on the population of framework pores between authigenic quartz grains. Secondary cracking of amorphous organic matter added porosity after initial infilling of porosity by oil and bitumen migration. Therefore, porosity is mainly controlled by abundance of authigenic silica and TOC, in spite of differences of burial diagenesis among various facies. Understanding these main controls on porosity should be helpful to predict and find and more porous facies and have a significant impact on future gas exploration in the Wufeng-Longmaxi Formations.Li, Z., Liu, D., Ranjith, P.G., Cai, Y., Wang, Y., 2018. Geological controls on variable gas concentrations: A case study of the northern Gujiao Block, northwestern Qinshui Basin, China. Marine and Petroleum Geology 92, 582-596. systematic investigation was performed on the variation of gas content and its geological controls based on the diverse geological data and the experimental results of 72 coal samples from 24 coalbed methane (CBM) wells in the northern Gujiao Block, NW Qinshui Basin, China. Coal rank varies from low-volatile bituminous coal to medium-volatile bituminous coal, with maximum vitrinite reflectance (Ro,max) ranging from 1.21 to 1.92%. CBM in the northern Gujiao Block is mainly produced from the relatively thick coal seams (～1.0 m-7.0?m), which are distributed in the Upper Carboniferous Taiyuan formation and Lower Permian Shanxi formation. The total gas content of coal seams ranges from 3.83 to 16.82?m3/t, with increasing gas content from marginal to central areas. Highly variable gas content reflects the comprehensive effect of various geological factors and coal reservoir properties. The results of the study show that the structural types, roof lithology, burial depth and hydrodynamic conditions are key factors controlling the gas content, whereas coal thickness and coal properties have no or little correlation with the gas content. In the northern Gujiao Block, three geological features controlling gas content are identified: 1) hydrodynamic trapping of gas in the graben structure with an adequate burial depth and impermeable roof, 2) gas loss by hydrodynamic flushing and normal faults in the syncline structure, and 3) gas migration by intensive movement of groundwater in the shallow burial area. The first mechanism is considered to cause the high gas content of central study area, whereas the other two mechanisms can explain the low gas content in the north-western and south-eastern regions.Li, Z., Shen, X., Qi, Z., Hu, R., 2018. Study on the pore structure and fractal characteristics of marine and continental shale based on mercury porosimetry, N2 adsorption and NMR methods. Journal of Natural Gas Science and Engineering 53, 12-21. gas, as one kind of unconventional gas, is an important energy supplement. The pore structure characteristic is an important index using to measure and evaluate shale reservoir quality. The Weiyuan marine shale (1#), Jiaoshiba marine shale (2#), Yaoqu tuff (4#) and Yaoqu continental shale (5# and 6#) were selected and subjected to mercury porosimetry (MP), N2 adsorption (NA) and (NMR) tests. The relationships between fractal dimensions and pore structure have been investigated by MP, NA and NMR to characterize the pore anisotropy. The results illustrate that the fractal dimensions of continental sample 5# and 6# are bigger than that of marine sample 2# in the pore range between 0.1 and 100?μm based on MP method. The fractal dimensions of marine sample 2# is bigger than those of continental sample 5# and 6# in the holes range between 2 and 200?nm based on NA method. In contrast, the fractal dimensions max(DNMR) of marine sample 2# is the largest among all the samples in the holes range between 10?nm and 10?μm based on NMR method. Especially, the fractal dimensions of Jiaoshiba marine sample 2# are biggest among all summarized samples in the holes range between 2 and 100?nm using NA and NMR method. That is to say the micropores of Jiaoshiba marine shale are the most development. Maybe it is one of the important reasons to obtain a great success of shale gas exploration in China. Therefore, the fractal dimension, as an important parameter, can be used to evaluate the fracturing effect of shale reservoir.Li, Z., Sun, X., Wang, F., Liang, Y., 2018. Microscopic flow characteristics of fluids in porous medium and its relationship with remaining oil distribution: A case study in Saertu oilfield of Daqing in China. Geofluids 2018, Article 7549831. Saertu Oilfield of Daqing in northeast China has entered ultrahigh water-cut stage of development. Numerical simulation is applied in this paper to study characteristics of microscopic fluid velocity and flow pressures variation in the core pores in the Beier Area of Saertu Oilfield. The relationship between the remaining oil distribution and microscopic flow characteristics of fluid in the pores has been analyzed. Study results show that, in the reservoir with stronger heterogeneity of grain size and throat (corresponding to high coordinate number), high flow velocities tend to occur in relatively wider pore throats with great differentiation of flow velocities. The dominant passages are developed in high capacity channel, the detour flows are created in large porous channels, and the isolated islands are formed in small porous channels. The flow velocity declines slowly with long duration of high pressure. Few pores are swept by injected fluids with low sweep efficiency. The microscopic remaining oil is mainly distributed in cluster state. The content of remaining oil is higher with lower oil displacement efficiency. By contrast, in the reservoir with weaker heterogeneity of grain size and throat (corresponding to low coordinate number), high flow velocities also develop in relatively narrower pore throats with little differentiation of flow velocities. The development of detour flows is weaker in large porous channels. The flow velocity declines quickly with a short duration of high pressure. More pores are swept by fluids with high sweep efficiency. The remaining oil is mainly distributed in state of thin film on pore surface. The content of remaining oil is lower with higher oil displacement efficiency.Liang, B., Zhang, K., Wang, L.-Y., Liu, J.-F., Yang, S.-Z., Gu, J.-D., Mu, B.-Z., 2018. Different diversity and distribution of archaeal community in the aqueous and oil phases of production fluid from high-temperature petroleum reservoirs. Frontiers in Microbiology 9, 841. doi: 10.3389/fmicb.2018.00841. get a better knowledge on how archaeal communities differ between the oil and aqueous phases and whether environmental factors promote substantial differences on microbial distributions among production wells, we analyzed archaeal communities in oil and aqueous phases from four high-temperature petroleum reservoirs (55–65°C) by using 16S rRNA gene based 454 pyrosequencing. Obvious dissimilarity of the archaeal composition between aqueous and oil phases in each independent production wells was observed, especially in production wells with higher water cut, and diversity in the oil phase was much higher than that in the corresponding aqueous phase. Statistical analysis further showed that archaeal communities in oil phases from different petroleum reservoirs tended to be more similar, but those in aqueous phases were the opposite. In the high-temperature ecosystems, temperature as an environmental factor could have significantly affected archaeal distribution, and archaeal diversity raised with the increase of temperature (p < 0.05). Our results suggest that to get a comprehensive understanding of petroleum reservoirs microbial information both in aqueous and oil phases should be taken into consideration. The microscopic habitats of oil phase, technically the dispersed minuscule water droplets in the oil could be a better habitat that containing the indigenous microorganisms.Liang, C., Cao, Y., Liu, K., Jiang, Z., Wu, J., Hao, F., 2018. Diagenetic variation at the lamina scale in lacustrine organic-rich shales: Implications for hydrocarbon migration and accumulation. Geochimica et Cosmochimica Acta 229, 112-128. carbonate-rich shales are well developed within the Mesozoic-Cenozoic strata of the Bohai Bay Basin (BBB) of eastern China and across southeast Asia. Developing an understanding of the diagenesis of these shales is essential to research on mass balance, diagenetic fluid transport and exchange, and organic-inorganic interactions in black shales. This study investigates the origin and distribution of authigenic minerals and their diagenetic characteristics, processes, and pathways at the scale of lacustrine laminae within the Es4s-Es3x shale sequence of the BBB. The research presented in this study is based on thin sections, field emission scanning electron microscope (FESEM) and SEM-catholuminescence (CL) observations of well core samples combined with the use of X-ray diffraction (XRD), energy dispersive spectroscopy, electron microprobe analysis, and carbon and oxygen isotope analyses performed using a laser microprobe mass spectrometer. The dominant lithofacies within the Es4s-Es3x sequence are a laminated calcareous shale (LCS-1) and a laminated clay shale (LCS-2). The results of this study show that calcite recrystallization1 is the overarching diagenetic process affecting the LCS-1, related to acid generation from organic matter (OM) thermal evolution. This evolutionary transition is the key factor driving the diagenesis of this lithofacies, while the transformation of clay minerals is the main diagenetic attribute of the LCS-2. Diagenetic differences occur within different laminae and at variable locations within the same lamina level, controlled by variations in mineral composition and the properties of laminae interfaces. The diagenetic fluid migration scale is vertical and responses (dissolution and replacement) are limited to individual laminae, between zero and 100?μm in width. In contrast, the dominant migration pathway for diagenetic fluid is lateral, along the abrupt interfaces between laminae boundaries, which leads to the vertical transmission of diagenetic responses. The recrystallization boundaries between calcite laminae act as the main migration pathways for the expulsion of hydrocarbons from these carbonate-rich lacustrine shales. However, because the interaction between diagenetic fluids and the shales themselves is limited to the scale of individual lamina, this system is normally closed. The occurrence of abnormal pressure fractures can open the diagenetic system, however, and cause interactions to occur throughout laminae; in particular, the closed-open (C–O) diagenetic process at this scale is critical to this shale interval. Multi-scale C–O systems are ubiquitous and episodic ranging from the scale of laminae to the whole basin. Observations show that such small-scale systems are often superimposed onto larger ones to constitute the complex diagenetic system seen within the BBB combining fluid transport, material and energy exchange, and solid-liquid and organic-inorganic interactions.Liang, W., Chen, Q., Peng, F., Shen, A., Hu, J., 2018. A novel surface-enhanced Raman scattering (SERS) detection for natural gas exploration using methane-oxidizing bacteria. Talanta 184, 156-161. bacteria (MOB), a unique group of Gram-negative bacteria utilizing methane as a sole source of carbon and energy, have been proved to be a biological indicator for gas prospecting. Field and cultivation-free detection of MOB is important but still challenging in current microbial prospecting of oil and gas (MPOG) system. Herein, SERS was used for the first time to our knowledge to investigate two species of methanotrophs and four closely relevant bacteria that universally coexisted in the upper soil of natural gas. A special but very simple approach was utilized to make silver nanoparticles (Ag NPs) sufficiently contact with every single bacterial cell, and highly strong and distinct Raman signals free from any native fluorescence have been obtained, and successfully utilized for distinguishing MOB from other species. A more convincing multi-Raman criterion based on single Raman bands, and further the entire Raman spectrum in combination with statistical analysis (e.g., principal component analysis (PCA)), which were found capable of classifying MOB related bacterial cells in soil with an accuracy of 100%. This study therefore demonstrated sensitive and rapid SERS measurement technique accompanied by complete Raman database of various gas reservoirs related bacteria could aid field exploration of natural gas reservoir.Limoges, A., Ribeiro, S., Weckstr?m, K., Heikkil?, M., Zamelczyk, K., Andersen, T.J., Tallberg, P., Massé, G., Rysgaard, S., N?rgaard‐Pedersen, N., Seidenkrantz, M.S., 2018. Linking the modern distribution of biogenic proxies in High Arctic Greenland shelf sediments to sea ice, primary production, and Arctic‐Atlantic inflow. Journal of Geophysical Research: Biogeosciences 123, 760-786. eastern north coast of Greenland is considered to be highly sensitive to the ongoing Arctic warming, but there is a general lack of data on modern conditions and in particular on the modern distribution of climate and environmental proxies to provide a baseline and context for studies on past variability. Here we present a detailed investigation of 11 biogenic proxies preserved in surface sediments from the remote High Arctic Wandel Sea shelf, the entrance to the Independence, Hagen, and Danmark fjords. The composition of organic matter (organic carbon, C:N ratios, δ13C, δ15N, biogenic silica, and IP25) and microfossil assemblages revealed an overall low primary production dominated by benthic diatoms, especially at the shallow sites. While the benthic and planktic foraminiferal assemblages underline the intrusion of chilled Atlantic waters into the deeper parts of the study area, the distribution of organic‐walled dinoflagellate cysts is controlled by the local bathymetry and sea ice conditions. The distribution of the dinoflagellate cyst Polarella glacialis matches that of seasonal sea ice and the specific biomarker IP25, highlighting the potential of this species for paleo sea ice studies. The information inferred from our multiproxy study has important implications for the interpretation of the biogenic‐proxy signal preserved in sediments from circum‐Arctic fjords and shelf regions and can serve as a baseline for future studies. This is the first study of its kind in this area. Lin, L., Yu, Y., Zhai, C., Li, Y., Wang, Y., Liu, G., Guo, Y., Gao, J., 2018. Paleogeography and shale development characteristics of the Late Permian Longtan Formation in southeastern Sichuan Basin, China. Marine and Petroleum Geology 95, 67-81. Late Permian Longtan Formation is extensively developed within the southeastern Sichuan basin which lies on the western margin of the Yangtze Plate in southwestern China. The stratigraphy and sequence boundaries of the Longtan Formation were interpreted from a combined study of field data, well log data and various data analysis in order to determine the extent and thickness of shale sequences. This interpretation defined the broad sequence stratigraphic framework and separated the Longtan Formation into three 3rd-order sequences. In addition, the formation was divided into five sedimentary facies using sedimentary, paleontological, geophysical and other data. The facies identified were fluvial, low energy shore, tidal flat, melanged accumulated shelf and platform basin. Three paleogeographic maps were created based on the 3rd-order sequences: SQ1, SQ2 and SQ3. The study shows that SQ1- SQ3 sedimentary environment of the study area, which extends from the southwest to northeast, was developed followed by fluvial, shore, tide, shallow water melanged accumulation shelf, deep water melanged accumulation shelf and platform basin.The mud shale rock types of the Longtan Formation that were identified are carbonaceous mud shale, silty mudstone and lime mudstone. According to the divided standard of mud shale effective thickness, there are three mud shale assemblages present in the sequences SQ1, SQ2, SQ3, namely, mud shale with sandstone, mud shale with limestone, and mud shale. SQ1 has the thickest mud shale identified on well logs. Mud shale with sandstone was well developed in the southwest of the study area and was interpreted to have been deposited in a shore or tidal flat sedimentary environment. This rock assemblage has a large effective thickness and extensive lateral distribution. In contrast, the assemblage of mud shale with limestone was mainly developed in the northeast of the study area and was interpreted to have formed in a melanged accumulation shelf sedimentary environment. The effective thickness of the mud shale with limestone is small and the distribution is limited. There is developed mud shale in above two type's sedimentary environment, but the distribution is also limited. The Longtan Formation's mud shale reached stage B diagenesis and is principally composed of quartz and clay minerals. The average quartz content is 43.40% and the average clay mineral content, which is mainly composed of illite, mixed illite/smectite, chlorite and kaolinite, is 39.58%. The sedimentary environment has controlled the distribution of minerals within the sequences. The clay mineral content gradually decreases as the sedimentary environment changes from shore-tidal flat in the southwest to deep water melanged accumulation shelf in the northeast. Therefore this comprehensive analysis shows that the southwest of the study area is the key area for shale gas exploration in the Longtan Formation.Lin, Y.-J., Perrard, A., Biswal, S.L., Hill, R.M., Trabelsi, S., 2018. Microfluidic investigation of asphaltenes-stabilized water-in-oil emulsions. Energy & Fuels 32, 4903-4910. study presents in situ visualization of the emulsification/demulsification of asphaltene-stabilized water-in-oil emulsions using microfluidic devices. Monodisperse water-in-oil emulsions were generated using a T-junction, and droplet coalescence was analyzed further upstream of the collision chamber. The state of aggregation of asphaltenes contained in the model oil was found to strongly affect the stability of the emulsions. The aqueous phases used in this study contained either surfactant (C12–15E7) or microemulsion with and without demulsifiers. Different demulsifiers and their concentrations were observed to dramatically affect the coalescence rate. The dilatational surface viscoelasticity properties were also measured using a pendant drop tensiometer. Surprisingly, no correlation was found between the dilatational surface viscoelasticity response and the coalescence rate of the water-in-oil emulsions.Lipczynska-Kochany, E., 2018. Humic substances, their microbial interactions and effects on biological transformations of organic pollutants in water and soil: A review. Chemosphere 202, 420-437. as large polymers by the traditional model, humic substances (HS) tend to be considered resistant to biodegradation. However, HS should be regarded as supramolecular associations of rather small molecules. There is evidence that they can be degraded not only by aerobic but also by anaerobic bacteria. HS presence alters biological transformations of organic pollutants in water and soil. HS, including humin, have a great potential for an application in aerobic and anaerobic wastewater treatment as well as in bioremediation. Black carbon materials, including char (biochar) and activated carbon (AC), long recognized effective sorbents, have been recently discovered to act as effective redox mediators (RM), which may significantly accelerate degradation of organic pollutants in a way similar to HS. Humic-like coating on the biochar surface has been identified. Explanation of mechanisms and possibility of applications of black carbon materials have only started to be explored. Results of many original and review papers, presented and discussed in this article, show an enormous potential for an interesting, multidisciplinary research as well as for a development of new, green technologies for biological wastewater treatment and bioremediation. Future research areas have been suggested.Liu, B., Qi, C., Mai, T., Zhang, J., Zhan, K., Zhang, Z., He, J., 2018. Competitive adsorption and diffusion of CH4/CO2 binary mixture within shale organic nanochannels. Journal of Natural Gas Science and Engineering 53, 329-336. dynamics simulations were performed to study adsorption and dynamics properties of pure CO2, pure CH4, and their mixtures confined to a graphene nanochannel with width of 3.25?nm at different loadings, temperature and molar ratios. Preferential adsorption CO2 over CH4 on the graphene nanochannel surface is observed by the density profile, the residence time of adsorbed molecules, CO2/CH4 selectivity, and the potential energy surface (PES). The CO2 preferentially adsorbed on the surface reduces the activation energy for CH4 diffusibility, and thus improves CH4 mobility. The increasing temperature leading to the decrease of CO2/CH4 selectivity and the enhancement of CO2/CH4 diffusion. Surface diffusion cannot be neglected on CO2/CH4 diffusion, especially at low loadings. The steric hindrance weakens the diffusion of both species at high loadings. The microscopic insight provided with this study is helpful to estimate and exploit the shale gas and evaluate CO2 sequestration capacity.Liu, F., Bomfleur, B., Peng, H., Li, Q., Kerp, H., Zhu, H., 2018. 280-m.y.-old fossil starch reveals early plant–animal mutualism. Geology 46, 423-426. is a major component in the human diet, and the acquisition of starch-rich food sources is considered a pivotal step in the biological and cultural evolution of humankind. However, the potential role of starch as an energy vector in paleo-ecosystems has never been addressed, obviously due to the lack of tangible records of pre-Quaternary starch grains. Here we describe ～280-m.y.-old lycopsid megaspores from Permian forest-swamp deposits in north China that bear caps of granular material. Size, shape, and surface structures as well as chemical and optical properties of these grains show that these caps are masses of compound storage starch. This is by far the oldest unequivocal record of fossil starch known to date. Deposition outside the actual megaspore container makes it unlikely that these starches were used for embryo nutrition; moreover, ultrathin sections of the megaspores indicate that they may have been produced after the megaspores were fertilized. By analogy to the elaiosomes on seeds of zoochorous plants today, we suggest that these starch caps were used to attract and reward animals, possibly land arthropods or snails, for megaspore dispersal. This study offers a rare glimpse into early stages of plant–animal co-evolution in Permian swamp-forest ecosystems.Liu, F., Hu, S., Guo, X., Niu, L., Cai, H., Yang, Q., 2018. Impacts of estuarine mixing on vertical dispersion of polycyclic aromatic hydrocarbons (PAHs) in a tide-dominated estuary. Marine Pollution Bulletin 131, Part A, 276-283. examine the impacts of estuarine mixing on the dispersion of polycyclic aromatic hydrocarbons (PAHs), seasonal variations in the vertical distribution of dissolved PAHs in the Humen River mouth of the Pearl River Estuary, which is a tide-dominated estuary, were thoroughly examined. An analysis of the vertical distribution of the concentration, composition and sources of PAHs indicates enhanced mixing of PAHs in January relative to June, which is strongly related to seasonal variations in the magnitude of estuarine mixing. Furthermore, the vertical distribution of PAHs initially indicated an increase and then a decrease from the surface layer to the bottom layer. In general, estuarine mixing promotes the vertical dispersion of PAHs, causing a more even PAHs distribution, while salinity stratification can trap PAHs, resulting in higher PAHs concentrations. Our study indicates that salinity variability stimulates significant dynamic effects regarding the dispersion of PAHs within estuarine environments.Liu, J., Steiner, M., Dunlop, J.A., Shu, D., 2018. Microbial decay analysis challenges interpretation of putative organ systems in Cambrian fuxianhuiids. Proceedings of the Royal Society B: Biological Sciences 285, Article 20180051. Chengjiang fossil Lagerst?tte (Cambrian Stage 3) from Yunnan, southern China is renowned for its soft-tissue preservation. Accordingly structures in fuxianhuiids, radiodontans and great appendage arthropods have been interpreted as the nervous and cardiovascular systems, including brains, hearts and blood vessels. That such delicate organ systems survive the fossilization process seems remarkable; given that this mode of preservation involves major taphonomic changes, such as flattening, microbial degradation, chemical alteration and replacement. Here, we document a range of taphonomic preservation states in numerous articulated individuals of Fuxianhuia protensa. We suggest that organic (partly iron mineral-replaced) bulbous structures in the head region, previously interpreted as brain tissue, along with sagittally located organic strands interpreted as part of the cardiovascular system or as nerve cords, may be better explained as microbial biofilms that developed following decomposition of the intestine, muscle and other connective tissues, forming halos surrounding the original organic remains.Liu, K., Ostadhassan, M., Gentzis, T., Carvajal-Ortiz, H., Bubach, B., 2018. Characterization of geochemical properties and microstructures of the Bakken Shale in North Dakota. International Journal of Coal Geology 190, 84-98. on unconventional shale reservoirs has increased dramatically due to the decline of production from conventional reserves. Geochemical properties and pore microstructures are known to be important factors that affect the storage capacity and nano-mechanical properties of self-sourced organic- rich shales. In this study, eleven shale samples were collected from the Upper and Lower Members of the Bakken Formation for the analysis of mineralogy, geochemical properties, and pore structure. Bulk pyrolysis analysis was conducted using the default method and two modified methods, namely the reservoir and the shale reservoir methods. Although all three methods showed the Bakken samples to be organic-rich and to have considerable remaining hydrocarbon generating potential, it was the shale reservoir method that gave the highest hydrocarbons yield because it captured most of the lighter thermo-vaporizable hydrocarbons. Thus, the shale method is considered to be more appropriate for the geochemical analysis of the Bakken samples. This method also showed that most of the remaining potential is due to the cracking of heavy hydrocarbons, NSO compounds (Resins+Asphaltenes) and kerogen. The organic matter in the samples is mixed II/III type (oil and gas-prone), is thermally mature, and plots at the peak of the oil window. The VRo-eq values, based on solid bitumen Ro measurements and conversion, ranged from 0.85% to 0.98%. The pore structures obtained from the image analysis method showed that total surface porosity of the samples ranged from 3.89% to 11.56% and that organic porosity is not the main contributor of total porosity for the samples analyzed. The pore structures of the samples are heterogeneous due to differences in lacunarity values. Results of the impact of mineralogical composition on pore structures demonstrate that clay minerals and feldspar have a positive influence on porosity while quartz, pyrite, and that TOC has a negative impact.Liu, K., Ostadhassan, M., Zou, J., Gentzis, T., Rezaee, R., Bubach, B., Carvajal-Ortiz, H., 2018. Nanopore structures of isolated kerogen and bulk shale in Bakken Formation. Fuel 226, 441-453. that exist within the organic matter can affect the total pore system of bulk shale samples and, as a result, need to be studied and analyzed carefully. In this study, samples from the Bakken Formation, in conjunction with the kerogen that was isolated from them, were studied and compared through a set of analytical techniques: X-ray diffraction (XRD), Rock-Eval pyrolysis, Fourier Transform infrared spectroscopy (FTIR), and gas adsorption (CO2 and N2). The results can be summarized as follows: 1) quartz and clays are two major minerals in the Bakken samples; 2) the samples have rich organic matter content with TOC greater than 10?wt%; 3) kerogen is marine type II; 4) gas adsorption showed that isolated kerogen compared to the bulk sample has larger micropore volume and surface area, meso- and macropore volume, and Brunauer–Emmett–Teller (BET) surface area; 5) deconvolution of pore size distribution (PSD) curves demonstrated that pores in the isolated kerogen could be separated into five distinct clusters, whereas bulk shale samples exhibited one additional pore cluster with an average pore size of 4?nm hosted in the minerals. The comparison of PSD curves obtained from isolated kerogen and bulk shale samples proved that most of the micropores in the shale are hosted within the organic matter while the mesopores with a size ranging between 2 and 10?nm are mainly hosted by minerals. The overall results demonstrated that organic matter-hosted pores make a significant contribution to the total porosity of the Bakken shale samples.Liu, N., Ding, L., Li, H., Zhang, P., Zheng, J., Weng, C.-H., 2018. Stable carbon isotope fractionation of chlorinated ethenes by a microbial consortium containing multiple dechlorinating genes. Bioresource Technology 261, 133-141. study aimed to determine the possible contribution of specific growth conditions and community structures to variable carbon enrichment factors (?-carbon) values for the degradation of chlorinated ethenes (CEs) by a bacterial consortium with multiple dechlorinating genes. ?-carbon values for trichloroethylene cis-1,2-dichloroethylene, and vinyl chloride were ?7.24%?±?0.59%, ?14.6%?±?1.71%, and ?21.1%?±?1.14%, respectively, during their degradation by a microbial consortium containing multiple dechlorinating genes including tceA and vcrA. The ?-carbon values of all CEs were not greatly affected by changes in growth conditions and community structures, which directly or indirectly affected reductive dechlorination of CEs by this consortium. Stability analysis provided evidence that the presence of multiple dechlorinating genes within a microbial consortium had little effect on carbon isotope fractionation, as long as the genes have definite, non-overlapping functions.Liu, P., Yuan, Z., Zhang, S., Xu, Z., Li, X., 2018. Experimental study of the steam distillation mechanism during the steam injection process for heavy oil recovery. Journal of Petroleum Science and Engineering 166, 561-567. distillation can effectively enhance heavy oil recovery during steam injection process in heavy oil reservoirs. However, the mechanism of steam distillation is complex, and the changes in oil properties during distillation remain unclear. In this study, three comparative steam distillation experiments were designed and conducted, including distillation processes employing saturated steam, steam superheated by 10?°C, and steam superheated by 40?°C. Heavy oil samples were derived from the Jin-1 Block in a typical heavy oilfield, in China. The density, viscosity, SARA fractions, and carbon number distribution of the residual oil were compared to those obtained before conducting steam distillation experiments. The steam distillation rates obtained with steam superheated by 40?°C, steam superheated by 10?°C, and saturated steam were 11.158%, 10.903% and 10.423%, respectively. The results indicate that the steam distillation rate of heavy oil increases significantly with increasing degree of superheating. During the steam distillation process, the density and viscosity of residual oil increase, the contents of saturated hydrocarbons and resin decrease, and the contents of aromatic hydrocarbons and asphaltenes increase. In addition, analysis of the distilled components indicates that lightweight components with smaller carbon numbers are removed firstly by steam distillation, followed by heavier components with larger carbon numbers. Moreover, all hydrocarbons with carbon numbers less than C22 are removed from heavy oil in the distillation process, while the maximum carbon number of the distilled components was C34. This study is favorable for understanding the changes in the properties of residual oil after distillation during the steam injection process for heavy oil recovery.Liu, Q., Kandasamy, S., Lin, B., Wang, H., Chen, C.-T.A., 2018. Biogeochemical characteristics of suspended particulate matter in deep chlorophyll maximum layers in the southern East China Sea. Biogeosciences, 15, 2091-2109. shelves and marginal seas are key sites of particulate organic matter (POM) production, remineralization and sequestration, playing an important role in the global carbon cycle. Elemental and stable isotopic compositions of organic carbon and nitrogen are thus frequently used to characterize and distinguish POM and its sources in suspended particles and surface sediments in the marginal seas. Here we investigated suspended particulate matter (SPM) collected around deep chlorophyll maximum (DCM) layers in the southern East China Sea for particulate organic carbon and nitrogen (POC and PN) contents and their isotopic compositions (δ13CPOC and δ15NPN) to understand provenance and dynamics of POM. Hydrographic parameters (temperature, salinity and turbidity) indicated that the study area was weakly influenced by freshwater derived from the Yangtze River during summer 2013. Elemental and isotopic results showed a large variation in δ13CPOC (?25.8 to ?18.2?‰) and δ15NPN (3.8 to 8.0?‰), but a narrow molar C?∕?N ratio (4.1–6.3) and low POC?∕?Chl a ratio (?<??200?g?g?1) in POM, and indicated that the POM in DCM layers was newly produced by phytoplankton. In addition to temperature effects, the range and distribution of δ13CPOC were controlled by variations in primary productivity and phytoplankton species composition; the former explained ?～??70?% of the variability in δ13CPOC. However, the variation in δ15NPN was controlled by the nutrient status and δ15NNO3? in seawater, as indicated by similar spatial distribution between δ15NPN and the current pattern and water masses in the East China Sea; although interpretations of δ15NPN data should be verified with the nutrient data in future studies. Furthermore, the POM investigated was weakly influenced by the terrestrial OM supplied by the Yangtze River during summer 2013 due to the reduced sediment supply by the Yangtze River and north-eastward transport of riverine particles to the northern East China Sea. We demonstrated that the composition of POM around DCM layers in the southern East China Sea is highly dynamic and largely driven by phytoplankton abundance. Nonetheless, additional radiocarbon and biomarker data are needed to re-evaluate whether or not the POM around the DCM water depths is influenced by terrestrial OM in the river-dominated East China Sea.Liu, R., Wang, L., Liu, Q., Wang, Z., Li, Z., Fang, J., Zhang, L., Luo, M., 2018. Depth-resolved distribution of particle-attached and free-living bacterial communities in the water column of the New Britain Trench. Frontiers in Microbiology 9, 625. doi: 10.3389/fmicb.2018.00625. (PA) and free-living (FL) microorganisms play significant but different roles in mineralization of organic matter (OM) in the ocean. Currently, little is known about PA and FL microbial communities in bathyal and abyssal pelagic waters, and understanding of their diversity and distribution in the water column and their interactions with environmental factors in the trench area is limited. We investigated for the first time the variations of abundance and diversities of the PA and FL bacterial communities in the epi-, bathy- and abyssopelagic zones of the New Britain Trench (NBT). The PA communities showed decreasing species richness but increasing relative abundance with depth, suggesting the increasing ecological significance of the PA bacteria in the deep ocean. The abundance and diversity of PA and FL bacterial communities in the NBT water column appeared to be shaped by different sets of environment factors, which might be related to different micro-niches of the two communities. Analysis on species distribution suggested that the differences between PA and FL bacteria communities mainly resulted from the different relative abundance of the “shared taxa” in the two types of communities. These findings provide valuable information for understanding the relative ecological roles of the PA and FL bacterial communities and their interactions with environmental factors in different pelagic zones along the vertical profile of the NBT water column.Liu, S., Deng, B., Jansa, L., Li, Z., Sun, W., Wang, G., Luo, Z., Yong, Z., 2018. Multi-stage basin development and hydrocarbon accumulations: A review of the Sichuan Basin at eastern margin of the Tibetan Plateau. Journal of Earth Science 29, 307-325. Basin is one of the uppermost petroliferous basins in China. It experienced three evolutionary phases which were marine carbonate platform (Ediacaran to Late Triassic), Indosinian-Yanshanian orogeny foreland basin (Late Triassic to Late Cretaceous) and uplift and tectonic modification (Late Cretaceous to Quaternary). The present-day tectonics of the Sichuan Basin and its periphery are characterized by three basic elements which are topography, basement type and surface structure, and two settings (plate margin and interior). Therefore, be subdivided into five units which have different structure and tectonic history. The basin contains five different sets of source rocks with thickness up to 2 500 m. These source rocks were well preserved due to the presence of Middel–Lower Triassic evaporites (>～200 m) and thick terrestrial sediments filling in the Indosinian-Yanshanian foreland basin (>3 000 m). The uplift and erosion since Late Cretaceous has significant influence on cross-strata migration and accumulation of oil and gas. The multi-phase evolution of the basin and its superimposed tectonic elements, good petroleum geologic conditions and diverse petroleum systems reveal its bright exploration prospects.Liu, W., Liao, Y., Shi, Q., Hsu, S.C., Jiang, B., Peng, P.a., 2018. Origin of polar organic sulfur compounds in immature crude oils revealed by ESI FT–ICR MS. Organic Geochemistry 121, 36-47. sulfur compounds (OSCs) are abundant in immature crude oils, including “polar” OSCs that are defined here as compounds containing one or more heteroatom(s) in addition to sulfur atoms having sufficient polarity to be analyzable by electrospray ionization (ESI) without derivatization. An understanding of the origins of polar OSCs in crude oils has been hampered by limitations in their analytical characterization. In this paper, we employed a high field (9.4 T) Fourier transform ion cyclotron resonance mass spectrometry (FT–ICR MS) coupled with ESI to study the sulfur-rich immature crude oils from the Jianghan Basin in China. The results show that the polar OSCs usually have non-sulfur counterparts, i.e., heteroatom-containing compounds without sulfur, with similar carbon number ranges, but slightly lower DBE (double bond equivalence) distributions. The similar or even identical carbon number distributions of the polar OSCs and their non-sulfur counterparts indicate their inheritance from the same precursors. The sulfur rings in polar OSCs are formed by intramolecular sulfurization that leads to the increases in DBEs compared to their non-sulfur counterparts. The results also indicate that the number of sulfur rings that can be formed in polar OSCs is largely controlled by the number of available reactive functional groups in their precursors. This paper extends our knowledge of intramolecular sulfurization during early diagenesis, especially for polar heteroatom-containing compounds.Liu, Y., Bai, Y., Xia, Z., Hou, J., 2018. Parameter optimization of Depressurization?to?Hot?Water?Flooding in heterogeneous hydrate bearing layers based on the particle swarm optimization algorithm. Journal of Natural Gas Science and Engineering 53, 403-415. the great importance of optimization parameters to the development performance of hydrate bearing layers (HBLs), this study developed an operation parameter optimization method by combining the particle swarm optimization (PSO) algorithm and the numerical simulator HydrateResSim (HRS), and then built a heterogeneous HBL model according to common geological parameters of HBLs. Comprehensively considering the economy in the early development stage and the final recovery of methane, the depressurization?to?hot?water?flooding exploitation method was applied in this model, and the critical gas production rate (the gas production rate corresponding to the conversion from depressurization to hot water flooding), injected water temperature, injection/production ratio and injection rate of each injection well were optimized via the proposed optimization method. Results showed that the developed optimization method could effectively improve the development performance of the heterogeneous HBL. The energy efficiency and methane recovery of the optimal case surpassed those of the initial case by 44% and 15.9%, respectively. The optimal injection/production ratio was 0.82, and the optimal injected water temperature was 83?°C. Initiating hot water flooding when the gas production rate declined to 30% of the peak value was preferred for the optimal development performance. Larger HBL thicknesses are helpful to obtain higher gas production rates for the production wells in both depressurization and hot water flooding stages due to the corresponding higher NGH reserves. Higher permeability leads to more gas production in the depressurization stage due to the corresponding higher reservoir conductivity, but less gas production in the hot water flooding stage due to the lower remaining NGH reserves and bottom water coning.Liu, Y., Wang, X., Li, Y., Chen, X., 2018. Metabolomic analysis of short-term sulfamethazine exposure on marine medaka (Oryzias melastigma) by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry. Aquatic Toxicology 198, 269-275. effects of sulfamethazine (SM2) have garnered increasing concern due to its wide applications in aquaculture and persistence in the aquatic environment. Most studies have main focused on freshwater fish (i.e. zebrafish), while information regarding effects of SM2 on marine species is still scarce. Here, the hepatotoxicities in marine medaka (Oryzias melastigma) with an increasing SM2 concentration exposures (0.01?mg/L, 0.1?mg/L and 1?mg/L) were assessed by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC?×?GC-TOF/MS) based metabolomics. Significant metabolites belonging to different metabolites classes were identified by multivariate statistical analysis. The increases levels of amino acids including alanine, asparagine, ornithine, proline, threonine, glutamic acid, lysine, tyrosine and phenylalanine were found in at least two exposure levels. Pathway analysis revealed that amino acids played important biological roles during SM2 exposure: up-regulation of high energy-related amino acids for energy alteration; immune function disorder, oxidative stress and corresponding toxicities defenses. The down regulations of sugar and fatty acid metabolism were observed with an increasing level of SM2 exposure, suggesting that extra energy for cellular defense and detoxification was demanded in terms of different stress request. This study provided an innovative perspective to explore possible SM2 induced hepatic damages at three exposure levels on a nontarget aquatic specie.Liu, Y., Xiong, Y., Li, Y., Peng, P.a., 2018. Effect of thermal maturation on chemical structure and nanomechanical properties of solid bitumen. Marine and Petroleum Geology 92, 780-793. abundance of organic matter is present as solid bitumen in highly mature shales. Changes in chemical structure of solid bitumen during catagenesis could alter the way its mechanical properties evolve. This study considers a series of solid bitumen samples artificially produced from the pyrolysis at 420–618?°C of soluble organic matter which originated from Maoming shale, to examine alternations in their chemical structure, nano-morphological and mechanical properties during maturation. Solid-state 13C nuclear magnetic resonance spectroscopy and elemental analysis were employed to characterize the structural changes. Young's modulus and microstructures were determined by atomic force microscopy. The results show that both structural (including C/H atomic ratio and carbon aromaticity) and mechanical (Young's modulus) variations in solid bitumen exhibit two staged evolutions (i.e., wet gas stage and dry gas stage) during maturation. In the wet gas stage (EasyRo 1.85%–2.64%), the C/H ratio and carbon aromaticity increase substantially with maturation, and the solid bitumen is relatively compliant with an average Young's modulus varying from 2.7?±?0.6 to 3.0?±?0.6?GPa. When maturity reaches to dry gas stage (EasyRo 2.64%–4.59%), structural parameters do not change greatly, whereas solid bitumen becomes much stiffer with modulus rising sharply to 7.2?±?1.1?GPa?at EasyRo 3.49% and further gently to 8.8?±?1.4?GPa?at EasyRo 4.59%. Concomitantly, great variations are observed on surface morphology, and the degree of heterogeneity in solid bitumen is recorded to be increasingly high along thermal simulation. Given the strong correlation between structural parameters and Young's modulus, we suggest that the stiffening of solid bitumen is extensively affected by its structural condensation due to the loss of aliphatic carbons and the increase of aromaticity.Liu, Z., Liu, Y., Zeng, G., Shao, B., Chen, M., Li, Z., Jiang, Y., Liu, Y., Zhang, Y., Zhong, H., 2018. Application of molecular docking for the degradation of organic pollutants in the environmental remediation: A review. Chemosphere 203, 139-150. molecular docking has been employed successfully to study the mechanism of biodegradation in the environmental remediation in the past few years, although medical science and biology are the main application areas for it. Molecular docking is a very convenient and low cost method to understand the reaction mechanism of proteins or enzymes with ligands with a high accuracy. This paper mainly provides a review for the application of molecular docking between organic pollutants and enzymes. It summarizes the fundamental knowledge of molecular docking, such as its theory, available softwares and main databases. Moreover, five types of pollutants, including phenols, BTEX (benzene, toluene, ethylbenzene, and xylenes), nitrile, polycyclic aromatic hydrocarbons (PAHs), and high polymer (e.g., lignin and cellulose), are discussed from molecular level. Different removal mechanisms are also explained in detail via docking technology. Even though this method shows promising application in the research of biodegradation, further studies are still needed to relate with actual condition.Longo, W.M., Huang, Y., Yao, Y., Zhao, J., Giblin, A.E., Wang, X., Zech, R., Haberzettl, T., Jardillier, L., Toney, J., Liu, Z., Krivonogov, S., Kolpakova, M., Chu, G., D'Andrea, W.J., Harada, N., Nagashima, K., Sato, M., Yonenobu, H., Yamada, K., Gotanda, K., Shinozuka, Y., 2018. Widespread occurrence of distinct alkenones from Group I haptophytes in freshwater lakes: Implications for paleotemperature and paleoenvironmental reconstructions. Earth and Planetary Science Letters 492, 239-250. are C35–C42 polyunsaturated ketone lipids that are commonly employed to reconstruct changes in sea surface temperature. However, their use in coastal seas and saline lakes can be hindered by species-mixing effects. We recently hypothesized that freshwater lakes are immune to species-mixing effects because they appear to exclusively host Group I haptophyte algae, which produce a distinct distribution of alkenones with a relatively consistent response of alkenone unsaturation to temperature. To evaluate this hypothesis and explore the geographic extent of Group I haptophytes, we analyzed alkenones in sediment and suspended particulate matter samples from lakes distributed throughout the mid- and high latitudes of the Northern Hemisphere (n=30n=30). Our results indicate that Group I-type alkenone distributions are widespread in freshwater lakes from a range of different climates (mean annual air temperature range: ?17.3–10.9?°C; mean annual precipitation range: 125–1657 mm?yr?1; latitude range: 40–81°N), and are commonly found in neutral to basic lakes (pH > 7.0), including volcanic lakes and lakes with mafic bedrock. We show that these freshwater lakes do not feature alkenone distributions characteristic of Group II lacustrine haptophytes, providing support for the hypothesis that freshwater lakes are immune to species-mixing effects. In lakes that underwent temporal shifts in salinity, we observed mixed Group I/II alkenone distributions and the alkenone contributions from each group could be quantified with the RIK37 index. Additionally, we observed significant correlations of alkenone unsaturation (U37K) with seasonal and mean annual air temperature with this expanded freshwater lakes dataset, with the strongest correlation occurring during the spring transitional season (U37K=0.029?T?0.49; r2=0.60r2=0.60; p<0.0001p<0.0001). We present new sediment trap data from two lakes in northern Alaska (Toolik Lake, 68.632°N, 149.602°W; Lake E5, 68.643°N, 149.458°W) that demonstrate the highest sedimentary fluxes of alkenones in the spring transitional season, concurrent with the period of lake ice melt and isothermal mixing. Together, these data provide a framework for evaluating lacustrine alkenone distributions and utilizing alkenone unsaturation as a lake temperature proxy.Lorenson, T.D., Collett, T.S., 2018. National Gas Hydrate Program Expedition 01 offshore India; gas hydrate systems as revealed by hydrocarbon gas geochemistry. Marine and Petroleum Geology 92, 477-492. National Gas Hydrate Program Expedition 01 (NGHP-01) targeted gas hydrate accumulations offshore of the Indian Peninsula and along the Andaman convergent margin. The primary objectives of coring were to understand the geologic and geochemical controls on the accumulation of methane hydrate and their linkages to underlying petroleum systems. Four areas were investigated: 1) the Kerala-Konkan Basin in the eastern Arabian Sea, 2) the Mahanadi and 3) Krishna-Godavari Basins in the western Bay of Bengal, and 4) the Andaman forearc Basin in the Andaman Sea.Upward flux of methane at three of the four of the sites cored during NGHP-01 is apparent from the presence of seafloor mounds, seismic evidence for upward gas migration, shallow sub-seafloor geochemical evidence of methane oxidation, and near-seafloor gas composition that resembles gas from depth.The Kerala-Konkan Basin well contained only CO2 with no detectable hydrocarbons suggesting there is no gas hydrate system here. Gas and gas hydrate from the Krishna-Godavari Basin is mainly microbial methane with δ13C values ranging from ?58.9 to ?78.9‰, with small contributions from microbial ethane (?52.1‰) and CO2. Gas from the Mahanadi Basin was mainly methane with lower concentrations of C2-C5 hydrocarbons (C1/C2 ratios typically >1000) and CO2. Carbon isotopic compositions that ranged from ?70.7 to ?86.6‰ for methane and ?62.9 to ?63.7‰ for ethane are consistent with a microbial gas source; however deeper cores contained higher molecular weight hydrocarbon gases suggesting a small contribution from a thermogenic gas source. Gas composition in the Andaman Basin was mainly methane with lower concentrations of ethane to isopentane and CO2, C1/C2 ratios were mainly >1000 although deeper samples were <1000. Carbon isotopic compositions range from ?65.2 to ?80.7‰ for methane, ?53.1 to ?55.2‰ for ethane is consistent with mainly microbial gas sources, although one value recorded of ?35.4‰ for propane suggests a thermogenic source. Gas hydrate accumulations in the Krishna-Godavari and Mahanadi Basins are the result of a microbially sourced gas hydrate system. The system is enhanced by the migration of microbial gas from surrounding areas through pathways including high-porosity delta sands, shale diapirism, faulting and folding of sediment due to the local processes associated with rapid sediment deposition, sediment overpressure, and the recycling of methane from a rapidly upward moving gas hydrate stability zone. The gas hydrate system in the Andaman Basin is less well constrained due to lack of exploration and occurs in a forearc basin. Each of these hydrate-bearing systems overlies and is likely supported by the presence and possible migration of gas from deeper gas-prone petroleum systems currently generating thermogenic hydrocarbons at much greater depths.Lorente, F.L., Pessenda, L.C.R., Oboh-Ikuenobe, F., Buso Junior, A.A., Rossetti, D.d.F., Giannini, P.C.F., Cohen, M.C.L., de Oliveira, P.E., Mayle, F.E., Francisquini, M.I., Fran?a, M.C., Bendassolli, J.A., Macario, K., 2018. An 11,000-year record of depositional environmental change based upon particulate organic matter and stable isotopes (C and N) in a lake sediment in southeastern Brazil. Journal of South American Earth Sciences 84, 373-384. aim of this paper is to reconstruct an 11,000-year history of depositional environmental change in southeastern Brazil, based upon the integration of particulate organic matter and stable isotope (C and N) data from a 136-cm sediment core from Lake Canto Grande. These proxies are used to explore the evolution of terrestrial and marine influence on the lake. Isotopic (δ13C: ?27.87‰ to ?31.9‰; δ15N: ?0.07‰–4.9‰) and elemental (total organic carbon - TOC: 0.58%–37.19%; total nitrogen - TN: 0.08%–1.73%; C/N: 0.3 to 54.7) values recorded in Lake Canto Grande suggest that the sedimentary organic matter was derived from mostly C3 land plants and freshwater phytoplankton. Particulate organic matter and cluster analyses distinguished four associations characterized by the predominance of amorphous organic matter, followed by phytoclasts and palynomorphs. These results indicate two different phases of lake evolution. The first phase (136 - 65?cm; ～10,943?cal?yr. B.P. to ～8529?cal?yr. B.P.) is recorded by sand layers interbedded with mud, which contain amorphous organic matter (AOM, 45–59%) and phytoclasts (opaques - OP: 6–18%; non-opaques – NOP: 17–23%) which indicate a floodplain area. The second phase (65–0?cm; ～8529?cal?yr. B.P. to ～662?cal?yr. B.P.) comprises mud, AOM (68–86%) and palynomorphs (PAL, 8–16%) related to lake establishment comparable to modern conditions. Thus, characterizing particulate organic matter, in combination with stable isotopes, proved to be invaluable proxies for lacustrine paleoenvironmental change through the Holocene.Lougheed, B.C., Metcalfe, B., Ninnemann, U.S., Wacker, L., 2018. Moving beyond the age–depth model paradigm in deep-sea palaeoclimate archives: dual radiocarbon and stable isotope analysis on single foraminifera. Climate of the Past 14, 515-526. palaeoclimate reconstructions from deep-sea sediment archives provide valuable insight into past rapid changes in ocean chemistry. Unfortunately, only a small proportion of the ocean floor with sufficiently high sediment accumulation rate (SAR) is suitable for such reconstructions using the long-standing age–depth model approach. We employ ultra-small radiocarbon (14C) dating on single microscopic foraminifera to demonstrate that the long-standing age–depth model method conceals large age uncertainties caused by post-depositional sediment mixing, meaning that existing studies may underestimate total geochronological error. We find that the age–depth distribution of our 14C-dated single foraminifera is in good agreement with existing bioturbation models only after one takes the possibility of Zoophycos burrowing into account. To overcome the problems associated with the age–depth paradigm, we use the first ever dual 14C and stable isotope (δ18O and δ13C) analysis on single microscopic foraminifera to produce a palaeoclimate time series independent of the age–depth paradigm. This new state of the art essentially decouples single foraminifera from the age–depth paradigm to provide multiple floating, temporal snapshots of ocean chemistry, thus allowing for the successful extraction of temporally accurate palaeoclimate data from low-SAR deep-sea archives. This new method can address large geographical gaps in late-glacial benthic palaeoceanographic reconstructions by opening up vast areas of previously disregarded, low-SAR deep-sea archives to research, which will lead to an improved understanding of the global interaction between oceans and climate.Lu, X., Armstrong, R.T., Mostaghimi, P., 2018. High-pressure X-ray imaging to interpret coal permeability. Fuel 226, 573-582. seam gas (CSG) is an unconventional resource drawing attention globally and is considered to play a crucial role in the future natural gas market. In CSG reservoirs, the characterisation of fracture aperture sizes is critical since coal permeability and wellbore performance are highly dependent on this parameter. To optimise gas recovery and predict gas production rate, it is important to analyse reservoir properties at in situ conditions. By using a high-pressure flow cell and X-ray microcomputed tomography (micro-CT) imaging, we visualise how the internal structure of coal changes under prevailing reservoir conditions. Important differences in the size of fractures can be seen from images of the coal sample obtained at different pressure. As anticipated, aperture size was found to decrease with increasing confining stress from atmospheric to reservoir pressures and it was more sensitive to the change of initial pressure. Similar conclusions were drawn for both gas and Klinkenberg-corrected permeability using helium and methane gases. In the permeability experiments, methane gas is used to mimick in situ conditions whereas helium is used for comparison as a non-adsorbing gas. There was less change in fracture aperture size if the ends of a coal cleat are sealed by minerals. We successfully applied micro-CT imaging on coal samples under high confining stress. The coal sample studied has a relatively large diameter compared to the common core sizes used for high-pressure imaging. Overall, this paper demonstrates a quantitative analysis of coal permeability at reservoir conditions, which provides a better understanding of deformation and further insights into enhanced CSG exploration and development techniques.Lübben, A., Leven, C., 2018. The Starzach site in Southern Germany: a site with naturally occurring CO2 emissions recovering from century-long gas mining as a natural analog for a leaking CCS reservoir. Environmental Earth Sciences 77, Article 316. this paper, we present the Starzach site, a region featuring numerous natural CO2 emission spots, such as mofettes, that reappeared after a longer period of extensive industrial CO2 mining. We discuss the results of a detailed literature study on the geological setting and the activities related to the gas mining in combination with own measurements to introduce the site as an example on how gas leakage from an insecure CCS reservoir could manifest at the surface. The site is in particular interesting for such investigations as the CO2 emissions started to replenish after the end of the CO2 mining and offers the unique possibility to investigate an increase in degassing activity as it might be expected for an active CCS site where leakage is suspected. Based on the geological setting and soil, gas emission, and isotope investigations, we further discuss the source of the CO2 emission and the gas ascent to the ground surface via deep-reaching faults, latter being so far excluded by previous work. The combination of our extensive literature review and recent field investigations allowed us to draw new geological conclusions for the site that were under discussion for a long time and to give insight into the site’s potential for CCS-related analog studies in the future.Luo, G., Richoz, S., van de Schootbrugge, B., Algeo, T.J., Xie, S., Ono, S., Summons, R.E., 2018. Multiple sulfur-isotopic evidence for a shallowly stratified ocean following the Triassic-Jurassic boundary mass extinction. Geochimica et Cosmochimica Acta 231, 73-87. cause of the Triassic-Jurassic (Tr-J) boundary biotic crisis, one of the ‘Big Five’ mass extinctions of the Phanerozoic, remains controversial. In this study, we analyzed multiple sulfur-isotope compositions (δ33S, δ34S and δ36S) of pyrite and Spy/TOC ratios in two Tr-J successions (Mariental, Mingolsheim) from the European Epicontinental Seaway (EES) in order to better document ocean-redox variations during the Tr-J transition. Our results show that upper Rhaetian strata are characterized by 34S-enriched pyrite, low Spy/TOC ratios, and values of Δ33Spy (i.e., the deviation from the mass-dependent array) lower than that estimated for contemporaneous seawater sulfate, suggesting an oxic-suboxic depositional environment punctuated by brief anoxic events. The overlying Hettangian strata exhibit relatively 34S-depleted pyrite, high Δ33Spy, and Spy/TOC values, and the presence of green sulfur bacterial biomarkers indicate a shift toward to euxinic conditions. The local development of intense marine anoxia thus postdated the Tr-J mass extinction, which does not provide support for the hypothesis that euxinia was the main killing agent at the Tr-J transition. Sulfur and organic carbon isotopic records that reveal a water-depth gradient (i.e., more 34S-, 13C-depleted with depth) in combination with Spy/TOC data suggest that the earliest Jurassic EES was strongly stratified, with a chemocline located at shallow depths just below storm wave base. Shallow oceanic stratification may have been a factor for widespread deposition of black shales, a large positive shift in carbonate δ13C values, and a delay in the recovery of marine ecosystems following the Tr-J boundary crisis.Luo, J.-H., Chen, H., Hu, S., Cai, C., Yuan, Z., Guo, J., 2018. Microbial selenate reduction driven by a denitrifying anaerobic methane oxidation biofilm. Environmental Science & Technology 52, 4006-4012. oxidation of methane (AOM) plays a crucial role in controlling the flux of methane from anoxic environments. Sulfate-, nitrite-, nitrate-, and iron-dependent methane oxidation processes have been considered to be responsible for the AOM activities in anoxic niches. We report that nitrate-reducing AOM microorganisms, enriched in a membrane biofilm bioreactor, are able to couple selenate reduction to AOM. According to ion chromatography, X-ray photoelectron spectroscopy, and long-term bioreactor performance, we reveal that soluble selenate was reduced to nanoparticle elemental selenium. High-throughput 16S rRNA gene sequencing indicates that Candidatus Methanoperedens and Candidatus Methylomirabilis remained the only known methane-oxidizing microorganisms after nitrate was switched to selenate, suggesting that these organisms could couple anaerobic methane oxidation to selenate reduction. Our findings suggest a possible link between the biogeochemical selenium and methane cycles.Luo, L., Wang, D., Yin, F., Liao, S., Ren, F., Ning, K., Tang, Y., 2018. Depositional sequence and carbon isotope chemostratigraphy of the Lower Carboniferous Xiangshan and Lower Permian Dingjiazhai Formations in Baoshan Block, Yunnan: Paleogeographic implications. Acta Sedimentologica Sinica 36, 291-301. understanding of the late Paleozoic sedimentary sequences in Baoshan block were obtained by detailed field measurement, borehole logging combined with sequence stratigraphic and facies studies as well as carbon and oxygen isotopic analysis of the lower Carboniferous Xiangshan Formation and lower Permian Dingjiazhai Formation at the Xiyi area, northern Baoshan Block. Three lithologic units were recognized in the Lower Carboniferous Xiangshan Formation, which are in ascending order represent lower slope, upper slope and carbonate platform depositional settings, respectively. The Lower Permian Dingjiazhai Formation was interpreted to be glacial-marine deposits according to distinctive pebbly calcareous moraine diamictite and local development of dropstones. The δ13CPDB profile demonstrates a gradual increasing trend up section in the Lower Carboniferous Xiangshan Formation, indicating a relatively stable sedimentary environment possible due to a steady increase of organic carbon burial. Combined with previous paleomagnetic results, biotic correlation and tectonic studies, it is presumed that the Baoshan Block was in a stable setting as a part of the northern Gondwana. However, the δ13CPDB values drop dramatically on the cessation of the pebbly moraine carbonate which represents the ending of glacial period, and correspond well with the first temperature rise event as well as massive basalt eruption in the early Permian. The above collectively indicate that the Baoshan Block was separated from the northeast Gondwana and started to drift northwards in the early Permian. The present study not only sheds light on the paleoceanic, paleogeographic and paleoclimatic significance of the Paleozoic Submasu Block, but also provides new carbon isotope chemostratigraphy for the contemporary sedimentary sequences.Luo, Q., Zhong, N., Liu, Y., Qu, Y., Ma, L., 2018. Organic geochemical characteristics and accumulation of the organic matter in the Jurassic to Cretaceous sediments of the Saihantala Sag, Erlian Basin, China. Marine and Petroleum Geology 92, 855-867. organic petrology and organic geochemistry of Jurassic to Cretaceous hydrocarbon source rocks from the Saihantala Sag, the Erlian Basin, have been analyzed to determine their geochemical characteristics, hydrocarbon potential and organic matter accumulation. The mudstones of the Alatanheli Formation (J1+2al), the Aershan Formation (K1ba), the lower Tengger member (K1bt1) and the upper Tengger member (K1bt2) and the Saihantala Formation (K1bs) contain variable total organic carbon concentrations and organic matter type. The observed macerals in the J1+2al, K1ba, K1bt1 and K1bt2 mudstones are sapropelinites (including lamalginites, mineral-bituminous groundmasses and rare telalginites), vitrinites and inertinites in order of abundance, whereas vitrinites and inertinites are the predominant macerals in the K1bs mudstones. The vitrinite reflectances are lower than 0.7% in the studied samples, suggestive of their low organic maturity, which is consistent with the strong yellow fluorescence of the lamalginites and telalginites, low Tmax values, the presence of 17β(H), 21β(H) hopanes and hop-17(21)-enes, and aliphatic and aromatic thermal maturity parameters. The studied samples were mainly deposited under anoxic saline lake environments. The major biological sources in the J1+2al, K1ba, K1bt1 and K1bt2 mudstones are bacteria and algae, whereas higher plants are the more important biological source in the K1bs mudstones as indicated by biomarkers and maceral contents. The J1+2al, K1ba, K1bt1 and K1bt2 mudstones mainly have more capacity to generate oil than gas, whereas the K1bs mudstones are mainly gas prone. Despite the low thermal maturity of the studied mudstones, abundant oil has been found in the southeast of the Saihantala Sag with mature source rocks. The nature of their generated products was due to their different formation mechanisms of organic matter accumulation. The organic matter accumulation in the J1+2al, K1ba, K1bt1 and K1bt2 mudstones was controlled by the high primary productivity and anoxic conditions, whereas the formation of the K1bs organic-rich sediments was mainly related with a high influx of higher plants.Lv, H., Sahin, N., Tani, A., 2018. Isolation and genomic characterization of Novimethylophilus kurashikiensis gen. nov. sp. nov., a new lanthanide‐dependent methylotrophic species of Methylophilaceae. Environmental Microbiology 20, 1204-1223., it has been found that two types of methanol dehydrogenases (MDHs) exist in Gram‐negative bacterial methylotrophs, calcium‐dependent MxaFI‐MDH and lanthanide‐dependent XoxF‐MDH and the latter is more widespread in bacterial genomes. We aimed to isolate and characterize lanthanide‐dependent methylotrophs. The growth of strain La2‐4T on methanol, which was isolated from rice rhizosphere soil, was strictly lanthanide dependent. Its 16S rRNA gene sequence showed only 93.4% identity to that of Methylophilus luteus MimT, and the name Novimethylophilus kurashikiensis gen. nov. sp. nov. is proposed. Its draft genome (ca. 3.69 Mbp, G?+?C content 56.1 mol%) encodes 3579 putative CDSs and 84 tRNAs. The genome harbors five xoxFs but no mxaFI. XoxF4 was the major MDH in the cells grown on methanol and methylamine, evidenced by protein identification and quantitative PCR analysis. Methylamine dehydrogenase gene was absent in the La2‐4T genome, while genes for the glutamate‐mediated methylamine utilization pathway were detected. The genome also harbors those for the tetrahydromethanopterin and ribulose monophosphate pathways. Additionally, as known species, isolates of Burkholderia ambifaria, Cupriavidus necator and Dyadobacter endophyticus exhibited lanthanide dependent growth on methanol. Thus, lanthanide can be used as an essential growth factor for methylotrophic bacteria that do not harbor MxaFI‐MDH. Lv, J., Han, R., Huang, Z., Luo, L., Cao, D., Zhang, S., 2018. Relationship between molecular components and reducing capacities of humic substances. ACS Earth and Space Chemistry 2, 330-339. substances (HSs) are collections of diverse organic compounds with broad redox capacities, which directly or indirectly affect the biogeochemical behaviors and fates of almost all the pollutants in the environment. The present study investigates the relationships between the molecular characteristics of HSs and their reducing capacities or electron-donating capacities (EDCs) by electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), total phenolic assay, and mediated electrochemical oxidation analysis. For decreasing the molecular heterogeneity of bulk HSs, HSs were first separated into three fractions according to their polarities. The results demonstrated that compounds in HS fractions with moderate polarity possessed a high content of total phenols and consistently had high EDCs. A strong linear correlation (R2 = 0.97) existed between EDCs and the total phenolic content, which confirmed that phenols contributed to the EDCs of HSs. Further analysis of molecular components confirmed that polyphenol-like compounds with medium oxygen content were the major moieties acting as electron donors in HSs. This study provides a linkage between the molecular components of HSs and their EDCs, which will help us to understand the molecular-dependent reducing properties of HSs or other dissolved organic matters under oxic conditions.Lynch Ianniello, I., Mendon?a, O.J., Arrieta, M.A., Bernardi, L., Bordach, M.A., 2018. Exploring dietary trends in late Holocene populations from Northwest Argentina: Insights from new data on stable isotope analysis (δ13C and δ15N). Journal of Archaeological Science: Reports 18, 617-627. the territory of Jujuy province, Northwest Argentina (NWA), a marked environmental diversity promoted the emergence of a wide spectrum of subsistence strategies during prehistoric times. This work explores the variability of human paleodiets from different environmental and temporal contexts of the province. Bone and tooth samples of 30 individuals from five archaeological sites were analysed: Til 20 (late Formative), Til 1, Yacoraite (Regional Developments and Inca), Til 43 (Hispanic-Indigenous) in Quebrada de Humahuaca, and Doncellas (Regional Developments and Inca) in Puna. The results of carbon and nitrogen isotopic analyses reveal a strong relevance of C4 resources and a balance between meat and plant components of the diet for Quebrada de Humahuaca. Late Formative site Til 20 exhibits more enriched δ13C and δ15N values than Regional Developments and Inca sites, reflecting higher consumption of C4 resources and a greater relevance of the meat component in diet or, alternatively, crop manuring practices. Hispanic-Indigenous samples exhibited intermediate isotopic values, which indicate the consumption of C4 and C3 plant resources and enriched animal protein. In Puna, δ15N values show certain homogeneity around values that reflect a balance between meat and plant components in the diet. It is also observed in this region a great dispersion of the δ13C values for organic and mineral fractions, ranging from those reflecting high intake of C4 resources to those where C3 resources have greater relevance.MacInnis, C.Y., Brunswick, P., Park, G.H., Buday, C., Schroeder, G., Fieldhouse, B., Brown, E.C., van Aggelen, G., Shang, D., 2018. Acute toxicity of Corexit EC9500A and assessment of dioctyl sulfosuccinate as an indicator for monitoring four oil dispersants applied to diluted bitumen. Environmental Toxicology and Chemistry 37, 1309-1319. present study investigated oil dispersant toxicity to fish species typical of the cooler regions of Canada, together with less well‐documented issues pertaining to oil dispersant monitoring. The oil dispersant toxicity of Corexit EC9500A was assessed for the freshwater fish species rainbow trout and the seawater species coho, chinook, and chum, with a final median lethal concentration (LC50) acute lethality range between 35.3 and 59.8?mg/L. The LC50 range was calculated using confirmed 0‐h dispersant concentrations that were justified by fish mortality within the first 24?h of exposure and by variability of the dispersant indicator dioctyl sulfosuccinate (DOSS) used to monitor concentrations at later time points. To investigate DOSS as an oil dispersant indicator in the environment, microcosm systems were prepared containing Corexit EC9500A, Finasol OSR52, Slickgone NS, and Slickgone EW dispersants together with diluted bitumen. The DOSS indicator recovery was found to be stable for up to 13 d at 5?°C, 8 d at 10?°C, but significantly less than 8 d at ≥15?°C. After 3 d at temperatures ≥15?°C, the DOSS indicator recovery became less accurate and was dependent on multiple environmental factors including temperature, microbial activity, and aeration, with potential for loss of solvents and stabilizers. A final assessment determined DOSS to be a discrepant indicator for long‐term monitoring of oil dispersant in seawater. MacLennan, M.S., Peru, K.M., Swyngedouw, C., Fleming, I., Chen, D.D.Y., Headley, J.V., 2018. Characterization of Athabasca lean oil sands and mixed surficial materials: Comparison of capillary electrophoresis/low‐resolution mass spectrometry and high‐resolution mass spectrometry. Rapid Communications in Mass Spectrometry 32, 695-702.: Oil sands mining in Alberta, Canada, requires removal and stockpiling of considerable volumes of near‐surface overburden material. This overburden includes lean oil sands (LOS) which cannot be processed economically but contain sparingly soluble petroleum hydrocarbons and naphthenic acids, which can leach into environmental waters. In order to measure and track the leaching of dissolved constituents and distinguish industrially derived organics from naturally occurring organics in local waters, practical methods were developed for characterizing multiple sources of contaminated water leakage. Methods: Capillary electrophoresis/positive‐ion electrospray ionization low‐resolution time‐of‐flight mass spectrometry (CE/LRMS), high‐resolution negative‐ion electrospray ionization Orbitrap mass spectrometry (HRMS) and conventional gas chromatography/flame ionization detection (GC/FID) were used to characterize porewater samples collected from within Athabasca LOS and mixed surficial materials. GC/FID was used to measure total petroleum hydrocarbon and HRMS was used to measure total naphthenic acid fraction components (NAFCs). HRMS and CE/LRMS were used to characterize samples according to source. Results: The amounts of total petroleum hydrocarbon in each sample as measured by GC/FID ranged from 0.1 to 15.1 mg/L while the amounts of NAFCs as measured by HRMS ranged from 5.3 to 82.3 mg/L. Factors analysis (FA) on HRMS data visually demonstrated clustering according to sample source and was correlated to molecular formula. LRMS coupled to capillary electrophoresis separation (CE/LRMS) provides important information on NAFC isomers by adding analyte migration time data to m/z and peak intensity. Conclusions: Differences in measured amounts of total petroleum hydrocarbons by GC/FID and NAFCs by HRMS indicate that the two methods provide complementary information about the nature of dissolved organic species in a soil or water leachate samples. NAFC molecule class OxSy is a possible tracer for LOS seepage. CE/LRMS provides complementary information and is a feasible and practical option for source evaluation of NAFCs in water. Madden, O., Chan, D.M.W., Dundon, M., France, C.A.M., 2018. Quantifying collagen quality in archaeological bone: Improving data accuracy with benchtop and handheld Raman spectrometers. Journal of Archaeological Science: Reports 18, 596-605. analysis of collagen and other endogenous protein in excavated bones is ever more common in paleontology and archaeology to determine dietary ecology, migration patterns, age, and diagenetic pathways. Decisions to sacrifice valuable samples to destructive stable isotope, radiogenic isotope, and proteomic analyses are easier to make if one knows ahead of time whether sufficient undegraded organic material is preserved in the bone for chemical analysis. Recent advances with near–infrared Raman spectroscopy to non-destructively pre-screen bones for the presence of undegraded endogenous protein can indicate whether original isotopic or proteomic signatures have remained intact in long-buried bones. However, it is crucial to examine the different emerging approaches with benchtop and handheld Raman spectrometers and to establish uniform data reporting standards that will allow laboratories to accurately compare results. Three recently published studies are compared to understand the factors that affect protein screening success and to establish best practices for the technique in the laboratory and in the field. A set of 37 archaeological human bone samples analyzed previously by the authors using FT-Raman spectroscopy are re-analyzed with a handheld 1064 nm Raman spectrometer such that the laser power was similar but the spectral resolution and signal-to-noise were lower. Two methods to identify peak heights were evaluated: 1) peak height fixed at a specific wavenumber and baseline anchored at fixed points bracketing the band and 2) averaging peak intensities over a short wavenumber range while also setting the baseline of the band by an average of several anchor points. This second method appeared to better classify whether the bones contained well-preserved protein signatures. In particular, peak height ratios of 960 cm?1 to 1636 cm?1 or 1450 cm?1 can indicate quality and abundance of bone protein, but have benefits and trade-offs that depend on the instrument used. The 960 cm?1:1636 cm?1 ratio is more descriptive of collagen quality as defined by an extracted carbon:nitrogen ratio of 2.8–3.6, but the 1636 cm?1 peak can be difficult to resolve well with an inherently less sensitive handheld Raman spectrometer. The 1450 cm?1 peak is more prominent in the spectrum and therefore more easily resolved with a handheld spectrometer, but it describes a common CH stretch found in collagen and other organic molecules.Mahaney, W.C., Krinsley, D.H., Milner, M.W., Fischer, R., Langworthy, K., 2018. Did the black-mat impact/airburst reach the Antarctic? Evidence from New Mountain near the Taylor Glacier in the Dry Valley Mountains. The Journal of Geology 126, 285-305. microscopic investigations of horizons in a surface paleosol, part of a pedostratigraphic stack of tills at New Mountain, Antarctica, dated to the middle Miocene climatic optimum event (ca. 15 Ma), suggest not only that the paleoclimate history of the continent can be read from stratigraphic layers within paleosols but also that records of cosmic events may lie embedded in coatings on sand clasts resident in paleosols. Recent microscopic and chemical data from sands in the upper horizons of a surface paleosol (Ant-828), adjacent to the Taylor Glacier, contain Fe and Na coatings surfaced with cosmic signatures including welded and shock-melted grains, opaque carbon coatings, microfeature stack of cards, Fe spherules, solubilized grain surfaces with streams of melted skin, a grain carrying an Ir signature, rare earth elements elevated above crustal averages, and slightly elevated Pt/Pd ratios. The projected link to the probable black-mat event of 12.8 ka is reinforced by the presence of fresh opaque carbon and other cosmic signatures on grain surfaces that overlie well-weathered grain features, presumably weathering from middle Miocene time near today. Evidence of CO2 and NOx accumulations dated to 12.9 ka in the Taylor Ice Dome suggest that the black-mat impact/airburst of the same time line as the Younger Dryas boundary may have reached across South America and the Pacific Ocean to the Dry Valley Mountains of Antarctica.Malazita, J.W., 2018. Astrobiology’s cosmopolitics and the search for an origin myth for the Anthropocene. Biological Theory 13, 111-120. article analyzes astrobiology as a cosmopolitical project—the ways in which astrobiological “sensemaking” practices do philosophical, political, cultural, ontological, and ethical work as much as they do scientific work. More specifically, this article argues that astrobiology is engaged in the crafting of a new “origin myth” that makes sense of humanity’s place in the universe during our transition from the Holocene to the Anthropocene. In doing so, this article traces the ways in which astrobiology employs scientific methodologies and engages with popular culture in ways that do four kinds of major work commonly found in origin myths: telling the origin story, demarcating the boundaries between self and the other, giving normative guidance, and declaring a shared societal purpose.Manuella, F.C., Scribano, V., Carbone, S., 2018. Abyssal serpentinites as gigantic factories of marine salts and oil. Marine and Petroleum Geology 92, 1041-1055. occur worldwide in various geological settings, such as in magma-starved oceanic basins. Abyssal serpentinites are long-term storage for chlorine and carbon, the latter forming dominantly reduced and subordinately oxidized compounds. Hence, serpentinites, salts, and reduced carbon phases coexist in an “abyssal association”. Although huge reservoirs of salts and reduced carbonaceous matter in abyssal serpentinites are thought to be lacking, this may be more a reflection of intrinsic limits in research methods than an indication of their absence. On the other hand, shallow-seated hydrocarbon-rich mud volcanoes and diapirs, consisting of salts, hydrocarbons (oils and gases), and clayey muds (including mudded serpentines) can provide evidence for such an oceanic association. Here, we search for scientific data in support of the “oceanic association”, and hence we propose a reappraisal of exploitable worldwide salt-hydrocarbon reservoirs, even gigantic in size. Abyssal serpentinites are well-known source rocks of abiotic gaseous hydrocarbons via Fischer-Tropsch-type reaction (FTT), whereas macromolecular carbonaceous matter (mostly bitumen) found in serpentinites is postulated to be biogenic. This inference is based mainly on three assumptions: (i) FTT in nature does not yield oils; (ii) hydrocarbons derive essentially from the thermal alteration of microbial molecules; (iii) the presence of biomarkers, traditionally considered evidence of the biological origin of oils. Nevertheless, some lines of strong evidence disprove these accepted conventions: (i) Lab experiments demonstrated that FTT can synthesize significant quantities of liquid hydrocarbons (oils) under conditions compatible with the deeper and more reduced level of serpentinite-hosted hydrothermal systems; (ii) macromolecules, generally thought to derive from microbial activity, can be abiotically generated as documented in extraterrestrial bodies; (iii) biomarkers are evidence for the proliferation of microbial communities, which subsist on serpentinization and FTT products, thus they are biological pollutants. Moreover, seawater-driven serpentinization consumes water producing huge amounts (～11?kg halite·m?3 of peridotite) of salts that can be stored in the deeper zone of abyssal-type hydrothermal systems. Thus, the origin of shallow-sited salt deposits, even gigantic in size, can be related to either the advective upwelling of hot hydrothermal brines, due to the dehydration of abyssal serpentinites, or to the passive upwelling of buoyant saline geobodies. Piercement structures are indeed seismically imaged in several localities, such as South Atlantic, the Gulf of Mexico, the Serpentinite belt extending from Cuba to Hispaniola, the North Sea trench, and the Zagros orogenic belt. Similar lines of evidence at the microscopic scale have been found in some Hyblean serpentinite xenoliths (south-eastern Sicily), being representative of the unmetamorfosed in-situ relic of the Palaeo-Tethys Ocean, upon which Sicily and its off-shore areas lie. In spite of the accepted stereotype of hydrocarbons as fossil fuels, and hence finite resources, reduced carbon compounds abiotically produced in abyssal serpentinites may be copious, protracted over time, and thus renewable.March, R., Doster, F., Geiger, S., 2018. Assessment of CO2 storage potential in naturally fractured reservoirs with dual‐porosity models. Water Resources Research 54, 1650-1668. Fractured Reservoirs (NFR's) have received little attention as potential CO2 storage sites. Two main facts deter from storage projects in fractured reservoirs: (1) CO2 tends to be nonwetting in target formations and capillary forces will keep CO2 in the fractures, which typically have low pore volume; and (2) the high conductivity of the fractures may lead to increased spatial spreading of the CO2 plume. Numerical simulations are a powerful tool to understand the physics behind brine‐CO2 flow in NFR's. Dual‐porosity models are typically used to simulate multiphase flow in fractured formations. However, existing dual‐porosity models are based on crude approximations of the matrix‐fracture fluid transfer processes and often fail to capture the dynamics of fluid exchange accurately. Therefore, more accurate transfer functions are needed in order to evaluate the CO2 transfer to the matrix. This work presents an assessment of CO2 storage potential in NFR's using dual‐porosity models. We investigate the impact of a system of fractures on storage in a saline aquifer, by analyzing the time scales of brine drainage by CO2 in the matrix blocks and the maximum CO2 that can be stored in the rock matrix. A new model to estimate drainage time scales is developed and used in a transfer function for dual‐porosity simulations. We then analyze how injection rates should be limited in order to avoid early spill of CO2 (lost control of the plume) on a conceptual anticline model. Numerical simulations on the anticline show that naturally fractured reservoirs may be used to store CO2.Marietou, A., Chastain, R., Beulig, F., Scoma, A., Hazen, T.C., Bartlett, D.H., 2018. The effect of hydrostatic pressure on enrichments of hydrocarbon degrading microbes from the Gulf of Mexico following the Deepwater Horizon oil spill. Frontiers in Microbiology 9, 808. doi: 10.3389/fmicb.2018.00808. Deepwater Horizon oil spill was one of the largest and deepest oil spills recorded. The wellhead was located at approximately 1500 m below the sea where low temperature and high pressure are key environmental characteristics. Using cells collected 4 months following the Deepwater Horizon oil spill at the Gulf of Mexico, we set up Macondo crude oil enrichments at wellhead temperature and different pressures to determine the effect of increasing depth/pressure to the in situ microbial community and their ability to degrade oil. We observed oil degradation under all pressure conditions tested [0.1, 15, and 30 megapascals (MPa)], although oil degradation profiles, cell numbers, and hydrocarbon degradation gene abundances indicated greatest activity at atmospheric pressure. Under all incubations the growth of psychrophilic bacteria was promoted. Bacteria closely related to Oleispira antarctica RB-8 dominated the communities at all pressures. At 30 MPa we observed a shift toward Photobacterium, a genus that includes piezophiles. Alphaproteobacterial members of the Sulfitobacter, previously associated with oil-degradation, were also highly abundant at 0.1 MPa. Our results suggest that pressure acts synergistically with low temperature to slow microbial growth and thus oil degradation in deep-sea environments.Mariscal, C., Fleming, L., 2018. Why we should care about universal biology. Biological Theory 13, 121-130. understanding of the universe has grown rapidly in recent decades. We’ve discovered evidence of water in nearby planets, discovered planets outside our solar system, mapped the genomes of thousands of organisms, and probed the very origins and limits of life. The scientific perspective of life-as-it-could-be has expanded in part by research in astrobiology, synthetic biology, and artificial life. In the face of such scientific developments, we argue there is an ever-growing need for universal biology, life-as-it-must-be, the multidisciplinary study of non-contingent aspects of life as guided by biological theory and constrained by the universe. We present three distinct but connected ways of universalizing biology—with respect to characterizing aspects of life everywhere, with respect to the explanatory scope of biological theory, and with respect to extending biological insights to the structure of nonbiological entities. For each of these, we sketch the theoretical goals and challenges, as well as give examples of current research that might be labeled universal biology.Marley, M.B., Brownstein, K.J., Lepper, B.T., Tushingham, S., Leone, K.L., Rafferty, S.M., Gang, D.R., Pansing, L.L., Pickard, W.H., Six, J., 2018. Analyses of organic residue from a conical pipe from the Niles-Wolford Mound (33Pi3), Pickaway County, Ohio. Journal of Archaeological Science: Reports 19, 658-668. Niles-Wolford Mound (33Pi3) was a conical Adena burial mound located along the Scioto River in Jackson Township, Pickaway County, Ohio. Excavations conducted in 1955 by the Ohio History Connection resulted in the discovery of a subfloor tomb with three burials. A tubular pipe found in association with one of the burials contained charred organic residue. Macrobotonical analysis of the material identified root or bark within the sample. Liquid chromatography-mass spectrometry (LC-MS) analyses detected the presence of various compounds, including an alkaloid. Radiocarbon dating places the mound to circa 2120?±?30?BP. This research furthers our understanding of the timing, geographical extent, and ceremonial contexts of prehistoric plant tobacco use by the Adena culture and demonstrates the importance of museum collections for addressing such questions.Marrugo-Hernandez, J.J., Prinsloo, R., Sunba, S., Marriott, R.A., 2018. Downhole kinetics of reactions involving alcohol-based hydraulic fracturing additives with implications in delayed H2S production. Energy & Fuels 32, 4724-4731. drilling in combination with hydraulic fracturing has dramatically changed the energy landscape as it allows for the more efficient extraction of natural gas from less accessible reservoirs. An issue being explored in greater detail is the increase of hydrogen sulfide (H2S) and mercaptan (CxHy-SH) content during the early production from hot shale gas reservoirs (T > 100 °C). Hydraulic fracturing technologies rely on the use of chemical additives for modifying the physical and chemical properties of fracturing fluids to drag proppant into the reservoir. Under downhole conditions, native H2S or metal sulfides can be partially oxidized by dissolved oxygen or other aqueous species, thus producing elemental sulfur. Over time, this elemental sulfur can slowly oxidize the chemical additives, thus regenerating H2S and other organosulfur species. In this work, we focus on the reaction kinetics of sulfur and alcohol reaction under downhole conditions. Rates and reactions are presented and discussed as an alternative mechanism for the delayed production of mercaptans and H2S.Martin, M., Legat, B., Leenders, J., Vanwinsberghe, J., Rousseau, R., Boulanger, B., Eilers, P.H.C., De Tullio, P., Govaerts, B., 2018. PepsNMR for 1H NMR metabolomic data pre-processing. Analytica Chimica Acta 1019, 1-13. the analysis of biological samples, control over experimental design and data acquisition procedures alone cannot ensure well-conditioned 1H NMR spectra with maximal information recovery for data analysis. A third major element affects the accuracy and robustness of results: the data pre-processing/pre-treatment for which not enough attention is usually devoted, in particular in metabolomic studies. The usual approach is to use proprietary software provided by the analytical instruments' manufacturers to conduct the entire pre-processing strategy. This widespread practice has a number of advantages such as a user-friendly interface with graphical facilities, but it involves non-negligible drawbacks: a lack of methodological information and automation, a dependency of subjective human choices, only standard processing possibilities and an absence of objective quality criteria to evaluate pre-processing quality. This paper introduces PepsNMR to meet these needs, an R package dedicated to the whole processing chain prior to multivariate data analysis, including, among other tools, solvent signal suppression, internal calibration, phase, baseline and misalignment corrections, bucketing and normalisation. Methodological aspects are discussed and the package is compared to the gold standard procedure with two metabolomic case studies. The use of PepsNMR on these data shows better information recovery and predictive power based on objective and quantitative quality criteria. Other key assets of the package are workflow processing speed, reproducibility, reporting and flexibility, graphical outputs and documented routines.Martínez, C., Gandolfo, M.A., Cúneo, N.R., 2018. Angiosperm leaves and cuticles from the uppermost Cretaceous of Patagonia, biogeographic implications and atmospheric paleo-CO2 estimates. Cretaceous Research 89, 107-118. study of plant material from localities of Late Cretaceous age from southern latitudes is fundamental to improve our understanding of global patterns of angiosperm evolution, diversity, paleoecology, and biogeography. Herein, angiosperm leaf fossils of the recently discovered Ca?adón del Loro locality, from the Maastrichtian portion of the Lefipán Formation, Patagonia, Argentina are studied. Leaf architecture was used to differentiate morphotypes, to describe them, and to make comparisons with other southern latitudes floras of similar age. Six angiosperm leaf morphotypes were described from 132 collected specimens; one of them, with exceptional preservation, was named Lefipania padillae gen. et sp. nov. and its cuticle anatomy and insect damage were also described. The Ca?adón del Loro fossils represent a local assemblage of low diversity deposited in an upper delta plain. Biogeographically, L. padillae was widespread throughout the southern hemisphere during the Late Cretaceous, possibly favored by a warm climate and the geographical proximity of these southern landmasses. The morphotype with well-preserved cuticles clearly shows four insect damage types attributed to feeding. This morphotype was also used for estimating paleo-atmospheric CO2 concentration (pCO2), using a stomatal-proxy gas exchange model, which resulted in approximately 464 ppm. The estimated pCO2 is in agreement with previous estimations for this time interval and supports the hypothesis of a decrease of pCO2 towards end of the Cretaceous.Mastalerz, M., Eble, C., Ames, P., Drobniak, A., 2018. Application of palynology and petrography in the correlation of the Pennsylvanian Brazil and Staunton Formation coals in the eastern part of the Illinois Basin. International Journal of Coal Geology 190, 191-204. coals of the Brazil and the lower part of the Staunton Formations (Atokan and early Desmoinesian, Pennsylvanian) in Indiana (Illinois Basin) are typically thin and discontinuous. As a result, both researchers and the industry have experienced problems with coal bed identification and correlation. The discrepancies in coal nomenclature and frequent miscorrelations affect coal exploration, mine planning, and communication between mines and customers. Our previous study, based on exploration boreholes, mine-scale observations, and coal quality and petrographic data from Daviess, Greene, and Clay Counties, Indiana, suggested that the coal mapped as the Upper Block Coal Member of Clay County might be the same seam as the Lower Block Coal Member of Daviess County. This study is an extension of the previous research conducted farther south to Pike, Warrick, and Spencer Counties, Indiana. In the southern part of Indiana, correlation of these late Atokan and early Desmoinesian coal beds is even more difficult because of the absence of well-defined marker horizons and limited mining and subsurface well data. Although palynological and coal petrography data generally correspond, these data alone cannot resolve the correlation of the coal beds in this southern region with the coals of Clay or Greene Counties, and they must be supplemented with the analysis of associated limestones. The ability to accurately identify the Perth Limestone Member, which occurs close to the Buffaloville Coal Member of the Brazil Formation, and the Holland Limestone Member, which occurs higher up in the Staunton Formation, will help to distinguish between Brazil and Staunton Formation coals.Mateos-Rivera, A., ?vre?s, L., Wilson, B., Yde, J.C., Finster, K.W., 2018. Activity and diversity of methane-oxidizing bacteria along a Norwegian sub-Arctic glacier forefield. FEMS Microbiology Ecology 94, Article fiy059. (CH4) is one of the most abundant greenhouse gases in the atmosphere and identification of its sources and sinks is crucial for the reliability of climate model outputs. Although CH4 production and consumption rates have been reported from a broad spectrum of environments, data obtained from glacier forefields are restricted to a few locations. We report the activities of methanotrophic communities and their diversity along a chronosequence in front of a sub-Arctic glacier using high-throughput sequencing and gas flux measurements. CH4 oxidation rates were measured in the field throughout the growing season during three sampling times at eight different sampling points in combination with laboratory incubation experiments. The overall results showed that the methanotrophic community had similar trends of increased CH4 consumption and increased abundance as a function of soil development and time of year. Sequencing results revealed that the methanotrophic community was dominated by a few OTUs and that a short-term increase in CH4 concentration, as performed in the field measurements, altered slightly the relative abundance of the OTUs.Mayali, X., Weber, P.K., 2018. Quantitative isotope incorporation reveals substrate partitioning in a coastal microbial community. FEMS Microbiology Ecology 94, Article fiy047. quantitatively link microbial identity with biogeochemical function, we carried out 14 simultaneous stable isotope probing experiments with organic and inorganic C and N substrates to measure the isotope incorporation by over one hundred co-occurring eukaryotic and prokaryotic populations in a coastal community. We found that nitrate was the most commonly incorporated substrate, and that light-driven carbon fixation was carried out by some bacterial taxa from the Flavobacteriales and OM60 (NOR5) clade, in addition to photoautotrophic phytoplankton. We found that organisms that incorporated starch, maltose, glucose, lactose and bicarbonate were phylogenetically clustered, suggesting that specific bacterial lineages specialized in the incorporation of these substrates. The data further revealed that coastal microorganisms spanned a range of resource utilization strategies from generalists to specialists and demonstrated a high level of substrate partitioning, with two thirds of taxa exhibiting unique substrate incorporation patterns and the remaining third shared by no more than three OTUs each. Specialists exhibited more extreme incorporation levels (high or low), whereas generalists displayed more intermediate activity levels. These results shed valuable insights into the bottom-up ecological strategies enabling the persistence of high microbial diversity in aquatic ecosystems.Mazzini, A., 2018. 10 years of Lusi eruption: Lessons learned from multidisciplinary studies (LUSI LAB). Marine and Petroleum Geology 90, 1-9. spectacular Lusi eruption started in northeast Java, Indonesia, on May 29th, 2006, continuously erupting mud, water, gas, oil, and clasts ever since. Lusi provides an unprecedented opportunity to study the birth and the evolution of a large-scale and hot mud eruption. Lusi is interpreted as a hybrid between a traditional hydrocarbon-driven piercement structure (mud volcano) and a hydrothermal system fuelled by magmatic heat. Lusi is therefore an exciting natural laboratory for understanding analogue modern and palaeo-piercement systems such as mud volcanoes, sediment-hosted hydrothermal systems, and hydrothermal vent complexes. This special issue collects recent multidisciplinary work completed in the framework of the ERC-funded LUSI LAB project. These studies were conducted at and near Lusi. Contributions span across disciplines such as engineering, geochemistry, geophysics, geology and numerical modelling, including fieldwork, laboratory and theoretical approaches. The acquired results contribute to characterise the dynamics of complex interactions between volcanism and an ongoing erupting clastic system. Lusi still saves many mysteries that will be unravelled by future scientific investigations.Mazzini, A., Scholz, F., Svensen, H.H., Hensen, C., Hadi, S., 2018. The geochemistry and origin of the hydrothermal water erupted at Lusi, Indonesia. Marine and Petroleum Geology 90, 52-66. spectacular Lusi mud-eruption started in northeast Java the 29th of May 2006. Despite extensive research, the origin of the erupted water remains elusive and poorly constrained. Here we present a comprehensive study of the geochemistry of Lusi waters compared with those collected from surrounding areas, all collected between 2006 and 2013, including data from mud volcanoes and volcano-hosted hydrothermal springs. Within this broad context, the geochemical characteristics of the fluids expelled in the Lusi region suggest that we can classify the waters in three groups: 1) meteoric waters expelled in cold springs and artesian wells, 2) hydrothermal waters typically mixed with meteoric waters, and 3) formation water from marine sediments altered by diagenetic processes such as clay-mineral dehydration. Samples collected from the Lusi crater are Cl and Na dominated (up to 527 mM and 471.7 mM, respectively) similar to seawater indicating that altered sedimentary formation waters are predominant in this system. In addition they are enriched in Sr (up to 808.4 μM) and other elements commonly associated with hydrothermal systems, such as Li (up to 877.6 μM compared to 26 μM in seawater). Some of these elements are up to ten times enriched compared to seawater values. High-temperature fluid mineral interactions in the subsurface appear to have facilitated the transfer of Li and other mobile elements into the fluids. High temperature fluid-mineral interaction reactions are also supported by Si concentrations significantly higher compared to other sampled mud volcanoes in the island. Crater samples also show the highest δ18O values (+5‰ after correction for evaporation compared to +1‰ at the MV localities). 87Sr/86Sr ratios vary between of 0.7077 and 0.7083 and seem to reflect a general mixture of fluids from clay-mineral dehydration, carbonate recrystallization, alteration of volcanic rocks and hydrothermal imprint. Eight years of geochemical monitoring indicate that the composition of the deep-sourced Lusi fluids remain fairly constant through time. Thus our findings show that the Lusi crater waters represent a regional geochemical anomaly, and we suggest that a combination of high temperatures in the source region, and fluid-rock interactions with silicates and, possibly, carbonate-rich lithologies can explain the data. This is consistent with a model where the emitted gases migrate from a deep-seated (>4 km) source region, likely associated with the presence of hot igneous intrusions and/or high T reactions related to the presence of neighbouring active volcanoes.McGuire, A.D., Lawrence, D.M., Koven, C., Clein, J.S., Burke, E., Chen, G., Jafarov, E., MacDougall, A.H., Marchenko, S., Nicolsky, D., Peng, S., Rinke, A., Ciais, P., Gouttevin, I., Hayes, D.J., Ji, D., Krinner, G., Moore, J.C., Romanovsky, V., Sch?del, C., Schaefer, K., Schuur, E.A.G., Zhuang, Q., 2018. Dependence of the evolution of carbon dynamics in the northern permafrost region on the trajectory of climate change. Proceedings of the National Academy of Sciences 115, 3882-3887.: We applied regional and global-scale biogeochemical models that coupled thaw depth with soil carbon exposure to evaluate the dependence of the evolution of future carbon storage in the northern permafrost region on the trajectory of climate change. Our analysis indicates that the northern permafrost region could act as a net sink for carbon under more aggressive climate change mitigation pathways. Under less aggressive pathways, the region would likely act as a source of soil carbon to the atmosphere, but substantial net losses would not occur until after 2100. These results suggest that effective mitigation efforts during the remainder of this century could attenuate the negative consequences of the permafrost carbon–climate feedback.Abstract: We conducted a model-based assessment of changes in permafrost area and carbon storage for simulations driven by RCP4.5 and RCP8.5 projections between 2010 and 2299 for the northern permafrost region. All models simulating carbon represented soil with depth, a critical structural feature needed to represent the permafrost carbon–climate feedback, but that is not a universal feature of all climate models. Between 2010 and 2299, simulations indicated losses of permafrost between 3 and 5 million km2 for the RCP4.5 climate and between 6 and 16 million km2 for the RCP8.5 climate. For the RCP4.5 projection, cumulative change in soil carbon varied between 66-Pg C (1015-g carbon) loss to 70-Pg C gain. For the RCP8.5 projection, losses in soil carbon varied between 74 and 652 Pg C (mean loss, 341 Pg C). For the RCP4.5 projection, gains in vegetation carbon were largely responsible for the overall projected net gains in ecosystem carbon by 2299 (8- to 244-Pg C gains). In contrast, for the RCP8.5 projection, gains in vegetation carbon were not great enough to compensate for the losses of carbon projected by four of the five models; changes in ecosystem carbon ranged from a 641-Pg C loss to a 167-Pg C gain (mean, 208-Pg C loss). The models indicate that substantial net losses of ecosystem carbon would not occur until after 2100. This assessment suggests that effective mitigation efforts during the remainder of this century could attenuate the negative consequences of the permafrost carbon–climate feedback.McKay, C.P., 2018. The search on Mars for a second genesis of life in the solar system and the need for biologically reversible exploration. Biological Theory 13, 103-110. discovery of a second genesis of life besides the one on Earth, this time on Mars, would have profound scientific and philosophical implications. Scientifically, it would provide a second example of biochemistry and of evolutionary history. Many important biological questions may be answerable through the comparison of biochemistry between the life forms on the two planets. Philosophically, the discovery of a second genesis of life in our solar system would suggest that the phenomenon of life is distributed throughout the universe. We could finally be confident that we are not alone. To protect a second genesis as we search for it, the robotic and human exploration of Mars should be done in a way that is biologically reversible, i.e., we must be able to undo our contamination of Mars if we discover a second genesis of life there. It is important to note that human exploration can be done in a way that is biologically reversible. Further, the discovery of a second genesis of life on Mars poses new questions in ethics. One question is: what ethical consideration is due to an alien life form when that life is distinctly different from Earth life, and the members of that life are no more advanced than microorganisms? Will we choose to terraform Mars to enhance the richness and diversity of the indigenous life we find there? In considering our answers to these questions, we should note that for most of Earth’s history our ancestors were microscopic.McMahon, P.B., Thomas, J.C., Crawford, J.T., Dornblaser, M.M., Hunt, A.G., 2018. Methane in groundwater from a leaking gas well, Piceance Basin, Colorado, USA. Science of The Total Environment 634, 791-801. and regional analysis of time-series hydrologic and geochemical data collected from 15 monitoring wells in the Piceance Basin indicated that a leaking gas well contaminated shallow groundwater with thermogenic methane. The gas well was drilled in 1956 and plugged and abandoned in 1990. Chemical and isotopic data showed the thermogenic methane was not from mixing of gas-rich formation water with shallow groundwater or natural migration of a free-gas phase. Water-level and methane-isotopic data, and video logs from a deep monitoring well, indicated that a shale confining layer ~125 m below the zone of contamination was an effective barrier to upward migration of water and gas. The gas well, located 27 m from the contaminated monitoring well, had ~1000 m of uncemented annular space behind production casing that was the likely pathway through which deep gas migrated into the shallow aquifer. Measurements of soil gas near the gas well showed no evidence of methane emissions from the soil to the atmosphere even though methane concentrations in shallow groundwater (16 to 20 mg/L) were above air-saturation levels. Methane degassing from the water table was likely oxidized in the relatively thick unsaturated zone (~18 m), thus rendering the leak undetectable at land surface. Drilling and plugging records for oil and gas wells in Colorado and proxies for depth to groundwater indicated thousands of oil and gas wells were drilled and plugged in the same timeframe as the implicated gas well, and the majority of those wells were in areas with relatively large depths to groundwater. This study represents one of the few detailed subsurface investigations of methane leakage from a plugged and abandoned gas well. As such, it could provide a useful template for prioritizing and assessing potentially leaking wells, particularly in cases where the leakage does not manifest itself at land surface.Melendez-Perez, J.J., Martínez-Mejía, M.J., Barcellos, R.L., Fetter-Filho, A.F.H., Eberlin, M.N., 2018. A potential formation route for CHOS compounds in dissolved organic matter. Marine Chemistry 202, 67-72. polyoxygenated organic compounds (CHOS compounds) had been detected in dissolved organic matter (DOM) from several aquatic systems around the world but the knowledge of its origin and geochemical behavior is still scarce. Previous studies have reported correlations between the content of CHOS compounds in DOM and the sulfide concentration in aquatic systems. We therefore performed a set of laboratorial experiments aiming to better understand the role of DOM in the sulfur cycle and we found that CHOS compounds can be formed in aquatic systems by the addition of sulfide/bisulfide ions to lignin-like CHO compounds. We also show that sediments act as heterogeneous catalysts that facilitate the formation of CHOS compounds.Mendillo, M., Withers, P., Dalba, P.A., 2018. Atomic oxygen ions as ionospheric biomarkers on exoplanets. Nature Astronomy 2, 287-291. ionized form of atomic oxygen (O+) is the dominant ion species at the altitude of maximum electron density in only one of the many ionospheres in our Solar System — Earth’s. This ionospheric composition would not be present if oxygenic photosynthesis was not an ongoing mechanism that continuously impacts the terrestrial atmosphere. We propose that dominance of ionospheric composition by O+ ions at the altitude of maximum electron density can be used to identify a planet in orbit around a solar-type star where global-scale biological activity is present. There is no absolute numerical value required for this suggestion of an atmospheric plasma biomarker — only the dominating presence of O+ ions at the altitude of peak electron density.Meslier, V., Casero, M.C., Dailey, M., Wierzchos, J., Ascaso, C., Artieda, O., McCullough, P.R., DiRuggiero, J., 2018. Fundamental drivers for endolithic microbial community assemblies in the hyperarid Atacama Desert. Environmental Microbiology 20, 1765-1781. hyperarid deserts, endolithic microbial communities colonize the rocks’ interior as a survival strategy. Yet, the composition of these communities and the drivers promoting their assembly are still poorly understood. We analysed the diversity and community composition of endoliths from four different lithic substrates – calcite, gypsum, ignimbrite and granite – collected in the hyperarid zone of the Atacama Desert, Chile. By combining microscopy, mineralogy, spectroscopy and high throughput sequencing, we found these communities to be highly specific to their lithic substrate, although they were all dominated by the same four main phyla, Cyanobacteria, Actinobacteria, Chloroflexi and Proteobacteria. Our finding indicates a fine scale diversification of the microbial reservoir driven by substrate properties. The data suggest that the overall rock chemistry and the light transmission properties of the substrates are not essential drivers of community structure and composition. Instead, we propose that the architecture of the rock, i.e., the space available for colonization and its physical structure, linked to water retention capabilities, is ultimately the driver of community diversity and composition at the dry limit of life. Mette, M.J., Whitney, N.M., Ballew, J., Wanamaker, A.D., 2018. Unexpected isotopic variability in biogenic aragonite: A user issue or proxy problem? Chemical Geology 483, 286-294. present study seeks to investigate sources of isotopic variability in the commonly used paleoclimate archive, the marine bivalve Arctica islandica, with an emphasis on the potential of human-induced variability arising from sampling techniques. Stable carbon (δ13Ccarbonate) and oxygen (δ18Ocarbonate) isotopes were analyzed for split (intra-sample) and replicate (intra- and inter-shell) samples taken from a group of laboratory-reared individuals, a natural population from northern Norway, and a natural population from the Gulf of Maine, USA. Compared to analytical uncertainty of 0.17‰ and 0.30‰ for δ13C and δ18O, respectively, among the natural populations, the mean difference between shell splits and shell replicates ranged from 0.12‰ and 0.33‰ for δ13C and δ18O, respectively. Our data suggest that heterogeneity of the carbonate material (i.e., large range of isotopic composition within one sample due to seasonal environmental variability) may contribute to “unexpected” variability more than human-induced error from sampling imprecision when collecting whole annual increments. Furthermore, δ13C from juvenile shells were highly variable (2σ standard deviation?=?0.65‰), approximately four times more variable than analytical precision.High precision among δ18O measurements of the laboratory-reared shells confirm the presumption that shells reliably and consistently precipitate in isotopic equilibrium with ambient seawater. Monte Carlo simulations of measurements from this population allowed characterization of improvements in uncertainty at increasing levels of replication. Substantial reduction in uncertainty occurs when increasing from two to three shells, however replication using a total of four shells further decreased uncertainty to within the 99% confidence level.Published studies sometimes compensate for uncertainties by replicating records over multiple individuals or multiple transects within the one individual. Oftentimes, however, isotope records are constructed from single individuals or transects and therefore fail to provide thorough estimates of proxy error. Our findings suggest that replication of carbon and oxygen isotope measurements of contemporaneously produced aragonite is necessary in order to reduce proxy-derived noise. Furthermore, population-specific estimates of uncertainty related to natural variability among individuals should be investigated in order to provide more realistic representations of proxy noise when reporting isotope time series.Meyer, K.W., Petersen, S.V., Lohmann, K.C., Winkelstern, I.Z., 2018. Climate of the Late Cretaceous North American Gulf and Atlantic Coasts. Cretaceous Research 89, 160-173. the response of temperature to elevated atmospheric CO2 during past greenhouse intervals such as the Late Cretaceous can constrain hypotheses of expected future warming tied to the rise of modern atmospheric CO2 levels. Here we present new reconstructions of Gulf and Atlantic Coast coastal marine temperatures through the late Campanian (～76–72 Ma) and Maastrichtian (72 Ma–66 Ma), as determined by carbonate clumped isotope analysis of marine bivalves and gastropods. We find temperatures in the range of ～7–25 °C across multiple sites located between 31°N and 36°N paleolatitude </topics/earth-and-planetary-sciences/paleolatitude>, and cooler temperatures of ～3–14 °C at sites around 39°N paleolatitude. Temperatures agree across a variety of taxa, indicating no appreciable organism-specific vital effects. The calculated paleotemperatures are very similar to modern marine temperatures at the same locations, despite the Late Cretaceous generally being considered a warmer interval. Clumped isotope temperatures are cooler than published temperatures from a nearby site measured using the TEX86 paleotemperature proxy, revealing a potential warm bias in TEX86 temperature estimates. The best agreement between clumped isotope and TEX86 temperatures is achieved when using the TEX86L calibration over TEX86H or BAYSPAR calibrations.Meysman, F.J.R., 2018. Cable bacteria take a new breath using long-distance electricity. Trends in Microbiology 26, 411-422., a new group of multicellular microorganisms was discovered, called ‘cable bacteria’, which are capable of generating and mediating electrical currents across centimetre-scale distances. By transporting electrons from cell to cell, cable bacteria can harvest electron donors and electron acceptors that are widely separated in space, thus providing them with a competitive advantage for survival in aquatic sediments. The underlying process of long-distance electron transport challenges some long-held ideas about the energy metabolism of multicellular organisms and entails a whole new type of electrical cooperation between cells. This review summarizes the current knowledge about these intriguing multicellular bacteria.Miao, Y., Warny, S., Clift, P.D., Gregory, M., Liu, C., 2018. Climatic or tectonic control on organic matter deposition in the South China Sea? A lesson learned from a comprehensive Neogene palynological study of IODP Site U1433. International Journal of Coal Geology 190, 166-177. and other organic particles are basic key components of palynofacies, yet quantitative analyses of all types are rarely used together to investigate organic matter assemblage changes and evaluate the driving forces behind the observed changes. In this paper, eight organic-walled microfossil and particle morphologies (sporopollen, Pediastrum, Concentricystes, fungi, dinoflagellate cysts, structured/amorphous organic matters, stomatal apparatus and scolecodonts) are tabulated and their concentrations and fluxes are evaluated over the past 17 million years (Ma) in sediments recovered from the South China Sea at International Ocean Discovery Program (IODP) Site U1433. Overall, these morphologies show roughly similar increasing trends but with different levels of fluctuations. The uniform increase in all morphologies at ~8Ma (named the ~8Ma event) is the most notable feature of the past 17Ma. To explain the trend, and because these various organic matters reflect various environmental conditions, we argue that the uniformity of the signal implies that tectonically-driven basin and drainage evolution played the key role, rather than paleoclimate (Asian summer monsoon). The ~8Ma event was likely triggered by the onset of the Mekong River in its present location, although the role of monsoon evolution cannot be excluded completely.Miller, D.R., Habicht, M.H., Keisling, B.A., Casta?eda, I.S., Bradley, R.S., 2018. A 900-year New England temperature reconstruction from in situ seasonally produced branched glycerol dialkyl glycerol tetraethers (brGDGTs). Climate of the Past Discussions 2018, 1-26. reconstructions are essential for distinguishing anthropogenic climate change from natural variability. An emerging method in paleoclimatology is the use of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in lacustrine sediments to reconstruct temperature, but their application is hindered by a limited understanding of their sources, seasonal production, and transport. We report seasonally resolved measurements of brGDGT production within the water column, in catchment soils and in a sediment sequence from a small, deep inland lake in Maine, USA. BrGDGT distributions in the water column are distinct from catchment soils but similar to the distributions in lake sediments, suggesting that (1) brGDGTs are produced within the lake and (2) this in situ production dominates the downcore sedimentary signal. Seasonally, depth-resolved measurements indicate that the dominant production of brGDGTs occurs in late fall/early spring and at intermediate depths (18–30 meters) in the water column. We apply these observations to help interpret a 900-year-long brGDGT-based temperature reconstruction and find that it shows similar trends to a pollen record from the same site and to regional and global syntheses of terrestrial temperatures over the last millennium. However, the record also shows higher-frequency variability than has previously been captured by such an archive in the Northeastern United States, potentially attributed to the North Atlantic Oscillation and volcanic/solar activity. This is the first brGDGT- based multi-centennial paleoreconstruction from this region and contributes to our understanding of the production and fate of brGDGTs in lacustrine systems.Miller, K., Simpson, E.L., Sherrod, L., Wizevich, M.C., Malenda, M., Morgano, K., Richardson, A., Livingston, K., Bogner, E., 2018. Gas bubble cavities in deltaic muds, Lake Powell delta, Glen Canyon National Recreation Area, Hite, Utah. Marine and Petroleum Geology 92, 904-912. produced by migrating gas, mainly methane, emanating from the near subsurface are a rarely reported sedimentary structure from either modern or ancient clastic sediments. The delta of the Colorado River in Lake Powell, Glen Canyon National Recreation Area provides an excellent recently accessible locality for examining soft sediment deformation structures generated by escaping gases and fluids. Sub-meter-scale to tens-of-meter-scale structures, including craters, salses, and sand and mud volcanoes are present on the modern Lake Powell delta. Abundant sub-centimeter-scale cavities are found in excavations through crater sediments and exposed along cut-bank exposures of the Colorado River. In cross section the cavities are subvertical, irregular-to sigmoidal-to lenticular-shaped, 1–3?mm short axes, up to ～3.0?cm long axes, and ～1?cm intermediate axes. Cavities are developed in cm-scale, laminated silty clay and clay graded beds. The tops of the cavities are wider than their bases. The cavities observed in the Lake Powell delta are interpreted as mode 1 fractures and probably represent a clastic morphologic analog to ‘molar-tooth’ carbonate structures. The characteristics of the cavities, and the geometries and deformation of the surrounding delta-mud host, are consistent with bubbles and fracturing generated by gas migration experiments and theoretical calculations but vary because of inherent heterogeneity of the sediments. Fractures developed as gas migrated into pre-existing cavities causing overpressure in cavities and leading to subvertical mode 1 fracture propagation. Recent sudden decompression related to rapid lake level drops of Lake Powell may have enhanced the release of gas, primarily bacterially produced, leading to the development of these soft sediment deformation structures.Miller, S.A., Mazzini, A., 2018. More than ten years of Lusi: A review of facts, coincidences, and past and future studies. Marine and Petroleum Geology 90, 10-25. Lusi mud eruption in East Java, Indonesia, has continued unabated for more than ten years with no end in sight. This review summarizes what has been learned about this intriguing system, from its inception to the current (2017) well-established metastable geysering system that continuously erupts mud breccia, gas, steam, and water. We discuss the initiation of Lusi, highlighting discrepancies and evidence through the published data, to build a comprehensive database that emphasizes how the results converge towards a natural scenario of this system. We argue that attempts to understand, constrain, or predict the behaviour of this system that rely on a drilling trigger can not explain subsequent observations. On the other hand, we show that a well-constrained conceptual model recognizing Lusi as a volcanically-linked hydrothermal system, has provided important insights for the documented observations over the last eleven years. The response of Lusi to the Yogykarta earthquake falls directly within the range of earthquake triggering phenomena (globally) of similar hydrothermal/geothermal systems, suggesting a natural trigger as the more likely culprit for the Lusi phenomenon. We also offer some future directions of additional scrutiny for understanding this newborn, tectonic scale, volcanic-hydrothermal complex.Mirabelli, M.F., Zenobi, R., 2018. Solid-phase microextraction coupled to capillary atmospheric pressure photoionization-mass spectrometry for direct analysis of polar and nonpolar compounds. Analytical Chemistry 90, 5015-5022. novel capillary ionization source based on atmospheric pressure photoionization (cAPPI) was developed and used for the direct interfacing between solid-phase microextraction (SPME) and mass spectrometry (MS). The efficiency of the source was evaluated for direct and dopant-assisted photoionization, analyzing both polar (e.g., triazines and organophosphorus pesticides) and nonpolar (polycyclic aromatic hydrocarbons, PAHs) compounds. The results show that the range of compound polarity, which can be addressed by direct SPME-MS can be substantially extended by using cAPPI, compared to other sensitive techniques like direct analysis in real time (DART) and dielectric barrier discharge ionization (DBDI). The new source delivers a very high sensitivity, down to sub parts-per-trillion (ppt), making it a viable alternative when compared to previously reported and less comprehensive direct approaches.Miyajima, Y., Watanabe, Y., Jenkins, R.G., Goto, A.S., Hasegawa, T., 2018. Diffusive methane seepage in ancient deposits: Examples from the Neogene Shin'etsu sedimentary basin, central Japan. Journal of Sedimentary Research 88, 449-466. continental margins, various types of methane seeps with a variety of flux rates, spatial extents, and durations occur. Although numerous studies have investigated spatially extensive high-flux-rate seeps, seeps with ephemeral and/or weak flows, known as diffusive seeps, have received less attention. This study investigates ancient diffusive methane seeps in the Shin'etsu sedimentary basin, central Japan, aiming to deduce their spatial extent and their sedimentological, paleontological, and geochemical properties. The seeps were identified as centimeter-scale carbonate concretions in two outcrops of Neogene siltstones in the basin. A comprehensive examination of the spatial distribution of the carbonates, their associated molluscan fossils, petrography, carbon and oxygen isotopic compositions, and lipid-biomarker contents of the concretions revealed that they originated from the anaerobic oxidation of methane (AOM) and formed via a weak, diffusive fluid flow. The small size and irregular or burrow-shaped morphologies of the concretions indicate that methane-bearing fluids diffused through small pore spaces such as burrows. Associated molluscan fossils consist of vesicomyids and other bivalves typical of methane seeps. Fossils of predator species were also identified, but epifaunal seep organisms are notably absent. The carbonate concretions are composed of strongly 13C-depleted micrite (δ13C values as low as ?46.0‰ vs. VPDB) with minor 13C-rich void-filling sparry cements. The presence of lipid biomarkers pentamethylicosane (PMI; with δ13C values as low as ?119‰) and biphytane and the absence of crocetane suggests that the AOM was performed by an ANME-1-dominated archaeal community. The insights of diffusive methane seepage in the geological record gained from this study can help to better understand depositional processes of seep deposits and variations in fluid flows in both ancient and modern methane-seeping systems.Mo, Y., Li, J., Jiang, B., Su, T., Geng, X., Liu, J., Jiang, H., Shen, C., Ding, P., Zhong, G., Cheng, Z., Liao, Y., Tian, C., Chen, Y., Zhang, G., 2018. Sources, compositions, and optical properties of humic-like substances in Beijing during the 2014 APEC summit: Results from dual carbon isotope and Fourier-transform ion cyclotron resonance mass spectrometry analyses. Environmental Pollution 239, 322-331. substances (HULIS) are a class of high molecular weight, light-absorbing compounds that are highly related to brown carbon (BrC). In this study, the sources and compositions of HULIS isolated from fine particles collected in Beijing, China during the 2014 Asia-Pacific Economic Cooperation (APEC) summit were characterized based on carbon isotope (13C and 14C) and Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analyses, respectively. HULIS were the main light-absorbing components of water-soluble organic carbon (WSOC), accounting for 80.2?±?6.1% of the WSOC absorption capacity at 365?nm. The carbon isotope data showed that HULIS had a lower non-fossil contribution (53?±?4%) and were less enriched with 13C (?24.2?±?0.6‰) relative to non-HULIS (62?±?8% and ?20.8?±?0.3‰, respectively). The higher relative intensity fraction of sulfur-containing compounds in HULIS before and after APEC was attributed to higher sulfur dioxide levels emitted from fossil fuel combustion, whereas the higher fraction of nitrogen-containing compounds during APEC may have been due to the relatively greater contribution of non-fossil compounds or the influence of nitrate radical chemistry. The results of investigating the relationships among the sources, elemental compositions, and optical properties of HULIS demonstrated that the light absorption of HULIS appeared to increase with increasing unsaturation degree, but decrease with increasing oxidation level. The unsaturation of HULIS was affected by both sources and aging level.Moghadasi, R., Rostami, A., 2018. New aspects of the asphaltene precipitation via interfacial tension measurement. Petroleum Science and Technology 36, 856-861. present study, the asphaltene precipitation was examined through pendant drop method regarding the impacts of oil composition, solvent type and concentration in both atmospheric and elevated pressures. Consequently, it is observed that there is a specific region for solvent concentration, in which the surface activity of nC5 is more than nC7 leading to the lower oil-water interfacial tension of nC5 diluted oil than that of nC7 diluted solutions. By decreasing resin to asphaltene ratio, this region will shift to the lower solvent concentrations. This finding could be of crucial value for analyzing the asphaltene precipitation in petroleum systems.Mohammed, S., Mansoori, G.A., 2018. Effect of CO2 on the interfacial and transport properties of water/binary and asphaltenic oils: Insights from molecular dynamics. Energy & Fuels 32, 5409-5417. conducted molecular dynamics (MD) simulations to investigate the effect of supercritical carbon dioxide (sc-CO2) on the interfacial and transport properties of water–oil systems. The oil phase was resembled by employing different binary hydrocarbons (paraffin + aromatic), namely, benzene + hexane, benzene + octane, xylene + hexane, and xylene + octane. Furthermore, we added an asphaltene to the system composed of xylene and hexane to study the interfacial behavior of the heaviest fraction of oil (asphaltene) in the presence of CO2. The simulations were performed under the operating conditions of 100 bar and 350 K. The results showed that aromatics, CO2, and asphaltenes accumulated at the interface at low CO2 mole fractions (xCO2). However, when xCO2 increased, it displaced the aromatics away from the interface and toward the bulk. At very high xCO2, the aromatics accumulated at the oil bulk. Similarly, asphaltene molecules stacked at the interface at low xCO2, and as xCO2 increased, some of the asphaltene molecules dissolved and aggregated in the oil bulk. CO2 forms a film between water and oil phases, and as the thickness of the film increases, it displaces the hydrocarbons away from the interface. The addition of sc-CO2 diluted the interface, formed hydrogen bonds (H bonds) with water, which stabilize the CO2 film, and reduced the interfacial tension in all systems. Furthermore, the addition of sc-CO2 increased the diffusivity of the oil phase in all systems. However, it significantly affected the diffusivity of systems that have less polar aromatics.Monnier, G.F., 2018. A review of infrared spectroscopy in microarchaeology: Methods, applications, and recent trends. Journal of Archaeological Science: Reports 18, 806-823. (IR) spectroscopy has emerged as one of the most powerful analytical tools available to archaeologists. It has been used to document site formation processes and understand the preservation of organic remains within sites; to investigate pyrotechnology including control of fire, heat treatment of stone, and plaster manufacture; to assess the preservation of charcoal and bone prior to dating or isotope analyses; and, to identify unknown substances inside containers or on artifact surfaces such as stone tools. Most importantly, IR spectroscopy has become an essential tool in the field of microarchaeology, the analysis of the portion of the archaeological record which cannot be seen with the naked eye, yet which contains a wealth of data to address the research areas listed above. IR spectroscopy, long a workhorse of analytical chemistry, is particularly suited to archaeology because it is applicable to many kinds of materials - organic as well as inorganic - and can therefore be used to address a wide range of questions. Sample preparation is rapid and, since minute quantities of a substance are necessary, the technique is ‘microdestructive’. It can also be performed on-site, yielding results in real time that help guide excavation and sampling strategies. The purpose of this review is to detail the basic principles and instrumentation of IR spectroscopy as it has been applied in microarchaeology and related fields of research. The discussion centers on major archaeological applications to date, methodological issues, and recent trends. A special focus is placed on new reflectance techniques.Monteil, C.L., Menguy, N., Prévéral, S., Warren, A., Pignol, D., Lefèvre, C.T., 2018. Accumulation and dissolution of magnetite crystals in a magnetically responsive ciliate. Applied and Environmental Microbiology 84, Article e02865-17.: Magnetotactic bacteria (MTB) represent a group of microorganisms that are widespread in aquatic habitats and thrive at oxic-anoxic interfaces. They are able to scavenge high concentrations of iron thanks to the biomineralization of magnetic crystals in their unique organelles, the so-called magnetosome chains. Although their biodiversity has been intensively studied, their ecology and impact on iron cycling remain largely unexplored. Predation by protozoa was suggested as one of the ecological processes that could be involved in the release of iron back into the ecosystem. Magnetic protozoa were previously observed in aquatic environments, but their diversity and the fate of particulate iron during grazing are poorly documented. In this study, we report the morphological and molecular characterizations of a magnetically responsive MTB-grazing protozoan able to ingest high quantities of MTB. This protozoan is tentatively identified as Uronema marinum, a ciliate known to be a predator of bacteria. Using light and electron microscopy, we investigated in detail the vacuoles in which the lysis of phagocytized prokaryotes occurs. We carried out high-resolution observations of aligned magnetosome chains and ongoing dissolution of crystals. Particulate iron in the ciliate represented approximately 0.01% of its total volume. We show the ubiquity of this interaction in other types of environments and describe different grazing strategies. These data contribute to the mounting evidence that the interactions between MTB and protozoa might play a significant role in iron turnover in microaerophilic habitats. Importance; Identifying participants of each biogeochemical cycle is a prerequisite to our understanding of ecosystem functioning. Magnetotactic bacteria (MTB) participate in iron cycling by concentrating large amounts of biomineralized iron minerals in their cells, which impacts their chemical environment at, or below, the oxic-anoxic transition zone in aquatic habitats. It was shown that some protozoa inhabiting this niche could become magnetic by the ingestion of magnetic crystals biomineralized by grazed MTB. In this study, we show that magnetic MTB grazers are commonly observed in marine and freshwater sediments and can sometimes accumulate very large amounts of particulate iron. We describe here different phagocytosis strategies, determined using magnetic particles from MTB as tracers after their ingestion by the protozoa. This study paves the way for potential scientific or medical applications using MTB grazers as magnetosome hyperaccumulators. Montgomery, W., Watson, J.S., Lewis, J.M.T., Zeng, H., Sephton, M.A., 2018. Role of minerals in hydrogen sulfide generation during steam-assisted recovery of heavy oil. Energy & Fuels 32, 4651-4654., E.K., Hao, J., Prabhu, A., Zhong, H., Jelen, B.I., Meyer, M., Hazen, R.M., Falkowski, P.G., 2018. Geological and chemical factors that impacted the biological utilization of cobalt in the Archean Eon. Journal of Geophysical Research: Biogeosciences 123, 743-759. geosphere and biosphere coevolved and influenced Earth's biological and mineralogical diversity. Changing redox conditions influenced the availability of different transition metals, which are essential components in the active sites of oxidoreductases, proteins that catalyze electron transfer reactions across the tree of life. Despite its relatively low abundance in the environment, cobalt (Co) is a unique metal in biology due to its importance to a wide range of organisms as the metal center of vitamin B12 (aka cobalamin, Cbl). Cbl is vital to multiple methyltransferase enzymes involved in energetically favorable metabolic pathways. It is unclear how Co availability is linked to mineral evolution and weathering processes. Here we examine important biological functions of Co, as well as chemical and geological factors that may have influenced the utilization of Co early in the evolution of life. Only 66 natural minerals are known to contain Co as an essential element. However, Co is incorporated as a minor element in abundant rock‐forming minerals, potentially representing a reliable source of Co as a trace element in marine systems due to weathering processes. We developed a mineral weathering model that indicates that dissolved Co was potentially more bioavailable in the Archean ocean under low S conditions than it is today. Mineral weathering, redox chemistry, Co complexation with nitrogen‐containing organics, and hydrothermal environments were crucial in the incorporation of Co in primitive metabolic pathways. These chemical and geological characteristics of Co can inform the biological utilization of other trace metals in early forms of life.Morales, S.E., Meyer, M., Currie, K., Baltar, F., 2018. Are oceanic fronts ecotones? Seasonal changes along the subtropical front show fronts as bacterioplankton transition zones but not diversity hotspots. Environmental Microbiology Reports 10, 184-189. are regarded as diversity hotspots in terrestrial systems, but it is unknown if this ‘ecotone effect’ occurs in the marine environment. Oceanic fronts are widespread mesoscale features, present in the boundary between different water masses, and are arguably the best potential examples of ecotones in the ocean. Here we performed the first seasonal study along an oceanic front, combining 16S rRNA gene sequencing coupled with a high spatial resolution analysis of the physical properties of the water masses. Using the Subtropical Frontal Zone off New Zealand we demonstrate that fronts delimit shifts in bacterioplankton community composition between water masses, but that the strength of this effect is seasonally dependent. While creating a transition zone where physicochemical parameters and bacterioplankton communities get mixed, this ecotone does not result in increased diversity. Thus unlike terrestrial ecotones, oceanic fronts are boundaries but not hotspots of bacterioplankton diversity in the ocean.Mori, F., Umezawa, Y., Kondo, R., Wada, M., 2018. Effects of bottom-water hypoxia on sediment bacterial community composition in a seasonally hypoxic enclosed bay (Omura Bay, West Kyushu, Japan). FEMS Microbiology Ecology 94, Article fiy053. bacterial community strongly drives carbon and other biogeochemical cycles in marine sediment. However, little is known about the impact of dissolved oxygen (DO) availability on bacterial community composition. To fill this gap, we examined diversity, richness and structure of the bacterial population for three consecutive years (2011–2013) in the uppermost (0–5 and 0–7 mm depth) and the subsurface layers (5–10 and 7–14 mm depth) of Omura Bay, Kyushu, Japan, a seasonally hypoxic enclosed bay. Automated ribosomal intergenic spacer analysis revealed a unimodal pattern of diversity indices with DO, peaking at the suboxic (11 μM O2) condition. Shifts in the bacterial communities were also evident in response to the availability of DO. Changes in the operational taxonomic units (OTUs) that were less abundant accounted for a large part of the community dissimilarity. It was further demonstrated that the relative abundance of OTUs affiliated with Gammaproteobacteria was correlated positively with DO, while that with Deltaproteobacteria was inversely correlated with DO. These results strongly suggest that DO availability of bottom water plays a fundamental role in shaping the bacterial community in sediment surfaces of shallow coastal areas.Muller, K.A., Esfahani, S.G., Chapra, S.C., Ramsburg, C.A., 2018. Transport and retention of concentrated oil-in-water emulsions in porous media. Environmental Science & Technology 52, 4256-4264. emulsions are routinely used in subsurface remediation. In these applications, high oil loadings present a challenge to remedial design as mechanistic insights into transport and retention of concentrated emulsions is limited. Column experiments were designed to examine emulsion transport and retention over a range of input concentrations (1.3–23% wt). Droplet breakthrough and retention data from low concentration experiments were successfully described by existing particle transport models. These models, however, failed to capture droplet transport in more concentrated systems. At high oil fraction, breakthrough curves exhibited an early fall at the end of the emulsion pulse and extending tailing. Irrespective of input concentration, all retention profiles displayed hyper-exponential behavior. Here, we extended existing model formulations to include the additional mixing processes occurring when at high oil concentrations—with focus on the influence of deposited mass and viscous instabilities. The resulting model was parametrized with low concentration data and can successfully predict concentrated emulsion transport and retention. The role of retained mass and viscous instabilities on mixing conditions can also be applied more broadly to systems with temporal or spatially variant water saturation or when viscosity contrasts exist between fluids.Müller, M.N., Krabbenh?ft, A., Vollstaedt, H., Brandini, F.P., Eisenhauer, A., 2018. Stable isotope fractionation of strontium in coccolithophore calcite: Influence of temperature and carbonate chemistry. Geobiology 16, 297-306. calcifying eukaryotic phytoplankton (coccolithophores) is a major contributor to the pelagic production of CaCO3 and plays an important role in the biogeochemical cycles of C, Ca and other divalent cations present in the crystal structure of calcite. The geochemical signature of coccolithophore calcite is used as palaeoproxy to reconstruct past environmental conditions and to understand the underlying physiological mechanisms (vital effects) and precipitation kinetics. Here, we present the stable Sr isotope fractionation between seawater and calcite (Δ88/86Sr) of laboratory cultured coccolithophores in individual dependence of temperature and seawater carbonate chemistry. Coccolithophores were cultured within a temperature and a pCO2 range from 10 to 25°C and from 175 to 1,240 μatm, respectively. Both environmental drivers induced a significant linear increase in coccolith stable Sr isotope fractionation. The temperature correlation at constant pCO2 for Emiliania huxleyi and Coccolithus braarudii is expressed as Δ88/86Sr = ?7.611 × 10?3 T + 0.0061. The relation of Δ88/86Sr to pCO2 was tested in Emiliania huxleyi at 10 and 20°C and resulted in Δ88/86Sr = ?5.394 × 10?5 pCO2 – 0.0920 and Δ88/86Sr = ?5.742 × 10?5 pCO2 – 0.1351, respectively. No consistent relationship was found between coccolith Δ88/86Sr and cellular physiology impeding a direct application of fossil coccolith Δ88/86Sr as coccolithophore productivity proxy. An overall significant correlation was detected between the elemental distribution coefficient (DSr) and Δ88/86Sr similar to inorganic calcite with a physiologically induced offset. Our observations indicate (i) that temperature and pCO2 induce specific effects on coccolith Δ88/86Sr values and (ii) that strontium elemental ratios and stable isotope fractionation are mainly controlled by precipitation kinetics when embedded into the crystal lattice and subject to vital effects during the transmembrane transport from seawater to the site of calcification. These results provide an important step to develop a coccolith Δ88/86Sr palaeoproxy complementing the existing toolbox of palaeoceanography. Mumford, A.C., Akob, D.M., Klinges, J.G., Cozzarelli, I.M., 2018. Common hydraulic fracturing fluid additives alter the structure and function of anaerobic microbial communities. Applied and Environmental Microbiology 84, Article e02729-17 : The development of unconventional oil and gas (UOG) resources results in the production of large volumes of wastewater containing a complex mixture of hydraulic fracturing chemical additives and components from the formation. The release of these wastewaters into the environment poses potential risks that are poorly understood. Microbial communities in stream sediments form the base of the food chain and may serve as sentinels for changes in stream health. Iron-reducing organisms have been shown to play a role in the biodegradation of a wide range of organic compounds, and so to evaluate their response to UOG wastewater, we enriched anaerobic microbial communities from sediments collected upstream (background) and downstream (impacted) of an UOG wastewater injection disposal facility in the presence of hydraulic fracturing fluid (HFF) additives: guar gum, ethylene glycol, and two biocides, 2,2-dibromo-3-nitrilopropionamide (DBNPA) and bronopol (C3H6BrNO4). Iron reduction was significantly inhibited early in the incubations with the addition of biocides, whereas amendment with guar gum and ethylene glycol stimulated iron reduction relative to levels in the unamended controls. Changes in the microbial community structure were observed across all treatments, indicating the potential for even small amounts of UOG wastewater components to influence natural microbial processes. The microbial community structure differed between enrichments with background and impacted sediments, suggesting that impacted sediments may have been preconditioned by exposure to wastewater. These experiments demonstrated the potential for biocides to significantly decrease iron reduction rates immediately following a spill and demonstrated how microbial communities previously exposed to UOG wastewater may be more resilient to additional spills. Importance: Organic components of UOG wastewater can alter microbial communities and biogeochemical processes, which could alter the rates of essential natural attenuation processes. These findings provide new insights into microbial responses following a release of UOG wastewaters and are critical for identifying strategies for the remediation and natural attenuation of impacted environments. Murugaiyan, J., Lewin, A., Kamal, E., Baku?a, Z., van Ingen, J., Ulmann, V., Unzaga Bara?ano, M.J., Humi?cka, J., Safianowska, A., Roesler, U.H., Jagielski, T., 2018. MALDI spectra database for rapid discrimination and subtyping of Mycobacterium kansasii. Frontiers in Microbiology 9, 587. doi: 10.3389/fmicb.2018.00587. kansasii is an emerging non-tuberculous mycobacterial (NTM) pathogen capable of causing severe lung disease. Of the seven currently recognized M. kansasii genotypes (I-VII), genotypes I and II are most prevalent and have been associated with human disease, whereas the other five (III-VII) genotypes are predominantly of environmental origin and are believed to be non-pathogenic. Subtyping of M. kansasii serves as a valuable tool to guide clinicians in pursuing diagnosis and to initiate the proper timely treatment. Most of the previous rapid diagnostic tests for mycobacteria employing the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) technology focused on species-level identification. The purpose of this study was to establish MALDI-TOF MS reference spectra database for discrimination of M. kansasii at the genotype level. A panel of 32 strains, representatives of M. kansasii genotypes I-VI were selected, whole cell proteins extracted and measured with MALDI-TOF MS. A unique main spectra (MSP) library was created using MALDI Biotyper Compass Explorer software. The spectra reproducibility was assessed by computing composite correlation index and MSPs cross-matching. One hundred clinical M. kansasii isolates used for testing of the database resulted in 90% identification at genus-level, 7% identification at species-level and 2% identification was below the threshold of log score value 1.7, of which all were correct at genotype level. One strain could not be identified. On the other hand, 37% of strains were identified at species level, 40% at genus level and 23% was not identified with the manufacturer's database. The MALDI-TOF MS was proven a rapid and robust tool to detect and differentiate between M. kansasii genotypes. It is concluded that MALDI-TOF MS has a potential to be incorporated into the routine diagnostic workflow of M. kansasii and possibly other NTM species.Nabiei, F., Badro, J., Dennenwaldt, T., Oveisi, E., Cantoni, M., Hébert, C., El Goresy, A., Barrat, J.-A., Gillet, P., 2018. A large planetary body inferred from diamond inclusions in a ureilite meteorite. Nature Communications 9, Article 1327. formation models show that terrestrial planets are formed by the accretion of tens of Moon- to Mars-sized planetary embryos through energetic giant impacts. However, relics of these large proto-planets are yet to be found. Ureilites are one of the main families of achondritic meteorites and their parent body is believed to have been catastrophically disrupted by an impact during the first 10 million years of the solar system. Here we studied a section of the Almahata Sitta ureilite using transmission electron microscopy, where large diamonds were formed at high pressure inside the parent body. We discovered chromite, phosphate, and (Fe,Ni)-sulfide inclusions embedded in diamond. The composition and morphology of the inclusions can only be explained if the formation pressure was higher than 20?GPa. Such pressures suggest that the ureilite parent body was a Mercury- to Mars-sized planetary embryo.Nagai, K., Shibata, T., Shinkura, S., Ohnishi, A., 2018. Poly(butylene terephthalate) based novel achiral stationary phase investigated under supercritical fluid chromatography conditions. Journal of Chromatography A 1549, 85-92.(butylene terephthalate) based novel stationary phase (SP), composed of planar aromatic phenyl group together with ester group monomer units, was designed for supercritical fluid chromatography (SFC) use. As expected from its structure, this phase shows planarity recognition of isomeric aromatics and closely similar compounds. Interestingly, for most analytes, the retention behavior of this SP is significantly distinct from that of the 2-ethylpyridine based SPs which is among the most well-known SFC dedicated phases. Although the poly(butylene terephthalate) is coated on silica gel, the performance of the column did not change by using extended range modifiers such as THF, dichloromethane or ethyl acetate and column robustness was confirmed by cycle durability testing.Naimark, E.B., Boeva, N.M., Kalinina, M.A., Zaytseva, L.V., 2018. Complementary transformations of buried organic residues and the ambient sediment: Results of long-term taphonomic experiments. Paleontological Journal 52, 109-122. (18 month) experiments were conducted, burying soft bodied organisms (Artemia salina, Crustacea) in marine sediment. For the first time in experimental taphonomy, the mineralogical transformation of the sediment that accompanied the process of decomposition was correlated with the degree of preservation. To obtain different quantitative characteristics of preservation, we used four dilutions of marine water (marine water: to fresh water as 1: 0; 1: 1, 1: 4, 1: 9). It was shown that higher dilutions corresponded to lower degrees of preservation. The proportion of kaolinite decreased in the marine sediment and, accordingly, the amorphous phase increased; in the diluted variants, the opposite pattern was revealed: the crystalline kaolinite phase increased and the amorphous phase decreased. Since no differences in the chemical composition of the residues from different dilutions were identified, the effect of sea salt concentration on preservation was considered to be negligible. A plausible hypothesis suggested that dissolving of kaolinite slows of organic decomposition and the beginnings of mineralization. Due to the acidic hydrolysis of kaolinite, Al cations appear in the solution; subsequently proteins are converted into insoluble forms, and thus escape from bacterial degradation. These taphonomic experiments reveal some overlooked physicochemical aspects important for the mechanisms of exceptional preservation. Original Russian Text ? E.B. Naimark, N.M. Boeva, M.A. Kalinina, L.V. Zaytseva, 2018, published in Paleontologicheskii Zhurnal, 2018, No. 2, pp. 3–15.Nair, R.R., Protasova, E., Strand, S., Bilstad, T., 2018. Membrane performance analysis for smart water production for enhanced oil recovery in carbonate and sandstone reservoirs. Energy & Fuels 32, 4988-4995. with specific ion composition is required for smart water production intended for enhanced oil recovery (EOR) in petroleum reservoirs. Membrane desalination is proposed in a unique configuration to deliver water with varying ionic composition for water injection in both carbonate and sandstone reservoirs. This research is dedicated to improve existing EOR technology and achieve environmentally friendly production of fossil fuels offshore. Present work addresses objectives, such as optimizing the nanofiltration (NF) membrane performance for smart water production from seawater in terms of flux, ion rejection, and power consumption for producing 1 m3 h–1 smart water. The power consumed for smart water production is calculated at 0.7 kWh m–3 for carbonates and 5.21 kWh m–3 for sandstones. NF membranes were chosen for smart water production over other desalination technologies as a result of their flexibility in altering ionic composition, low energy requirements, low chemical usage, and small footprint along with ease of operation. Smart water production from seawater considerably reduces use of fresh water during offshore water injection and is environmentally friendly.Najjar, R.G., Herrmann, M., Alexander, R., Boyer, E.W., Burdige, D.J., Butman, D., Cai, W.J., Canuel, E.A., Chen, R.F., Friedrichs, M.A.M., Feagin, R.A., Griffith, P.C., Hinson, A.L., Holmquist, J.R., Hu, X., Kemp, W.M., Kroeger, K.D., Mannino, A., McCallister, S.L., McGillis, W.R., Mulholland, M.R., Pilskaln, C.H., Salisbury, J., Signorini, S.R., St‐Laurent, P., Tian, H., Tzortziou, M., Vlahos, P., Wang, Z.A., Zimmerman, R.C., 2018. Carbon budget of tidal wetlands, estuaries, and shelf waters of eastern North America. Global Biogeochemical Cycles 32, 389-416.: Carbon cycling in the coastal zone affects global carbon budgets and is critical for understanding the urgent issues of hypoxia, acidification, and tidal wetland loss. However, there are no regional carbon budgets spanning the three main ecosystems in coastal waters: tidal wetlands, estuaries, and shelf waters. Here we construct such a budget for eastern North America using historical data, empirical models, remote sensing algorithms, and process‐based models. Considering the net fluxes of total carbon at the domain boundaries, 59 ± 12% (± 2 standard errors) of the carbon entering is from rivers and 41 ± 12% is from the atmosphere, while 80 ± 9% of the carbon leaving is exported to the open ocean and 20 ± 9% is buried. Net lateral carbon transfers between the three main ecosystem types are comparable to fluxes at the domain boundaries. Each ecosystem type contributes substantially to exchange with the atmosphere, with CO2 uptake split evenly between tidal wetlands and shelf waters, and estuarine CO2 outgassing offsetting half of the uptake. Similarly, burial is about equal in tidal wetlands and shelf waters, while estuaries play a smaller but still substantial role. The importance of tidal wetlands and estuaries in the overall budget is remarkable given that they, respectively, make up only 2.4 and 8.9% of the study domain area. This study shows that coastal carbon budgets should explicitly include tidal wetlands, estuaries, shelf waters, and the linkages between them; ignoring any of them may produce a biased picture of coastal carbon cycling. Plain Language Summary: A carbon budget for a particular site or region describes the inputs and outputs of carbon to that site or region as well as the processes that change carbon from one form to another. A carbon budget is needed to fully understand many important issues facing coastal waters. We constructed the carbon budget for coastal waters of eastern North America. We found that about 60% of the carbon entering the domain is from rivers and about 40% is from the atmosphere, while about 80% of the carbon leaving the domain goes to the open ocean and about 20% is buried. Transfers of carbon from wetlands to estuaries and from estuaries to the ocean were as important as transfers of carbon at the domain boundaries. Tidal wetlands and estuaries were found to be important to the carbon budget despite making up only 2.4 and 8.9% of the study domain area, respectively. This study shows that coastal carbon budgets should explicitly consider tidal wetlands, estuaries, shelf waters, and the linkages between them; ignoring any of them may produce a biased picture of coastal carbon cycling. Neuberger, N., Adidharma, H., Fan, M., 2018. Graphene: A review of applications in the petroleum industry. Journal of Petroleum Science and Engineering 167, 152-159., in its pure or derivative form has been a topic of increasing importance in the scientific community for many years. However, its application in the oil and gas industry has only been popularized in the last few years, with the bulk of research taking place within the last ten years or less. Due to graphene's unique chemical, structural, electrical, and mechanical properties, it shows applicability for many areas within the oil and gas industry. Areas of application include drilling, lubrication, desalination, anti-corrosion coatings, cementing, oil-water separation, oil spill cleanup, and emulsion stabilization to name a few. This paper reviews graphene and its derivatives as they apply to the oil and gas industry and describes how this revolutionary substance will have impacts on the technology of the industry for years to come. The main factor preventing immediate implementation into the industry is not scientific, but rather economic and industrial. Scaling up laboratory results to a size that is applicable to the oil and gas industry in a cost efficient manner will prove to be the largest obstacle moving forward.Ni, X., Jiang, G., Liu, F., Deng, Z., 2018. Synthesis of an amphiphobic nanofluid with a novel structure and its wettability alteration on low-permeability sandstone reservoirs. Energy & Fuels 32, 4747-4753. address the water-blocking and water-sensitivity issues in low-permeability sandstone reservoirs, this paper describes a simple method to synthesize amphiphobic nanofluids by combining nanosilica, multi-walled carbon nanotubes (MCNTs), and trichloro(1H,1H,2H,2H-perfluorooctyl)silane. These fluids process bead chain structures with a special chemical property that alters the sandstone core surface from amphiphilic to amphiphobic. To examine the wettability alteration of the sandstone core surface after treatment with amphiphobic nanofluids, contact angle tests, calculations of the surface free energy, liquid level measurements, spontaneous imbibition tests, permeability recovery experiments, and oil recovery experiments were carried out. The results showed that the contact angle of deionized water on the sandstone core surface reached up to 160°, 120°, and 110° and the contact angle of hexadecane reached up to 133°, 88°, and 91° after treatment with the amphiphobic nanofluids, the modified nanosilica nanofluids, and the modified MCNT nanofluids, respectively. Meanwhile, these three nanofluids decreased the surface free energy to 0.73, 6.80, and 9.70 mN/m; in addition, they reduced the liquid level from 40 to ?46, ?30, and ?16 mm in deionized water and from 24 to ?16, ?2, and 1 mm in hexadecane, respectively. The amphiphobic nanofluids lowered the spontaneous imbibition volume more effectively than the other two nanofluids. As the wettability in the sandstone core surface was altered from amphiphilic to amphiphobic, well recovery of the sandstone core permeability increased and resulted in an approximately 9% enhancement of the oil recovery.Nicholson, W.L., Schuerger, A.C., Douki, T., 2018. The photochemistry of unprotected DNA and DNA inside Bacillus subtilis spores exposed to simulated martian surface conditions of atmospheric composition, temperature, pressure, and solar radiation. Astrobiology 18, 393-402. is considered a potential biomarker for life-detection experiments destined for Mars. Experiments were conducted to examine the photochemistry of bacterial DNA, either unprotected or within Bacillus subtilis spores, in response to exposure to simulated martian surface conditions consisting of the following: temperature (?10°C), pressure (0.7?kPa), atmospheric composition [CO2 (95.54%), N2 (2.7%), Ar (1.6%), O2 (0.13%), and H2O (0.03%)], and UV–visible–near IR solar radiation spectrum (200–1100?nm) calibrated to 4 W/m2 of UVC (200–280?nm). While the majority (99.9%) of viable spores deposited in multiple layers on spacecraft-qualified aluminum coupons were inactivated within 5?min, a detectable fraction survived for up to the equivalent of ～115 martian sols. Spore photoproduct (SP) was the major lesion detected in spore DNA, with minor amounts of cyclobutane pyrimidine dimers (CPD), in the order TT CPD?>?TC CPD?>>?CT CPD. In addition, the (6-4)TC, but not the (6-4)TT, photoproduct was detected in spore DNA. When unprotected DNA was exposed to simulated martian conditions, all photoproducts were detected. Surprisingly, the (6-4)TC photoproduct was the major photoproduct, followed by SP ～ TT CPD?>?TC CPD?>?(6-4)TT?>?CT CPD?>?CC CPD. Differences in the photochemistry of unprotected DNA and spore DNA in response to simulated martian surface conditions versus laboratory conditions are reviewed and discussed. The results have implications for the planning of future life-detection experiments that use DNA as the target, and for the long-term persistence on Mars of forward contaminants or their DNA.Nie, F., He, D., Guan, J., Li, X., Hong, Y., Wang, L., Zheng, H., Zhang, Q., 2018. Oil sand pyrolysis: Evolution of volatiles and contributions from mineral, bitumen, maltene, and SARA fractions. Fuel 224, 726-739. order to investigate the pyrolysis behavior through the volatile evolution, pyrolyzer-evolved gas analysis-mass spectrometry and thermogravimetric analysis-mass spectrometry were adopted for in situ analysis and comparison the pyrolytic volatiles derived from two different oil sands as well as their mineral, bitumen, maltene and SARA fractions. For both oil sands, the weight loss and volatile release during the oil-producing process exhibited two stages: a devolatilization stage (<350?°C) and a thermal-cracking stage (350–600?°C). These two stages afforded different volatile yields and displayed distinct activation energy distributions. Additionally, heart-cut analysis indicated that the volatiles were in disparate compositions at each stage. The volatile evolution of the oil sand bitumen, maltene, and SARA fractions revealed individual contributions on volatile release with increasing pyrolysis temperature. Specifically, volatiles in the devolatilization stage predominantly originated from the saturates in maltene. These resulted in a significant amount of polycyclic biomarkers and contributed toward the release of higher-molecular-weight substances over a temperature range of 200–350?°C. The thermal-cracking stage was the main stage in which most of the gaseous and light pyrolytic products, including amounts of alkanes and olefins, were generated. These compounds mostly originated from cracking of resin and asphaltenes. The aromatic fraction was observed that released volatiles in both stages. Thus, due to the disparity in temperature region for volatile release, the volatile yields during the different stages of the process were mainly determined from the organic constituents of the oil sand. Notably, the volatile compositions predominantly correlated to the original organic structures. Moreover, the minerals exhibited little influence during the oil-producing stage of the two oil sand samples under the tested heating conditions. However, the presence of interactions between these organic sub-fractions during oil sand pyrolysis is suggested.Nowamooz, A., Comeau, F.-A., Lemieux, J.-M., 2018. Evaluation of the potential for gas leakage along wellbores in the St. Lawrence Lowlands basin, Quebec, Canada. Environmental Earth Sciences 77, Article 303. attributes (i.e., deviation, casings and plugging characteristics) for 85 wells in the St. Lawrence Lowlands basin of southern Quebec were compiled from drilling reports and abandonment programs to provide an overview of the abandoned well characteristics and to establish a diagnosis on the long-term reliability of the completion and abandonment practices carried out by the companies since the beginning of oil and gas exploration. Using these data, the conventional and unconventional wells were divided into four categories: (1) conventional wells drilled before 1950, (2) conventional wells drilled between 1950 and 1970, (3) conventional wells drilled after 1970 and shale gas wells (all drilled after 2000). Very little information was available for wells drilled before 1950. More information was available for the wells drilled from 1950 to 1970 which is considered a transition period between old and modern technology. Conventional and unconventional wells drilled after 1970 were generally well documented and their attributes corresponded to API standards. A decision tree, inspired from the methodology proposed by Watson and Bachu (SPE Drill Complet 24(1):115–126, 2009. ), was then created to assess the potential of leakage of each of the conventional and unconventional wells using the compiled attributes. The factors defining the probability of well leakage were wellbore deviation, height of cement in casing annuli (partially or fully cemented), type of abandonment plugs (cement or mechanical plugs) and drilling date (before or after 1970). Among the 85 wells assessed by this tree, the probability of leakage was higher than 50% for 55 wells (65% of wells). Wellbore deviation and lack of information on the construction and abandonment methods were respectively the primary and secondary causes of high probability of leakage of these wells.Nú?ez-Useche, F., Canet, C., Liebetrau, V., Puig, T.P., Ponciano, A.C., Alfonso, P., Berndt, C., Hensen, C., Mortera-Gutierrez, C., Rodríguez-Díaz, A.A., 2018. Redox conditions and authigenic mineralization related to cold seeps in central Guaymas Basin, Gulf of California. Marine and Petroleum Geology 95, 1-15. carbonate crusts, surface muds and bivalve shell fragments have been recovered from inactive and active recently discovered cold seep sites in central Guaymas Basin. In this study, for first time, redox conditions and fluid sources involved in mineral precipitation were investigated by analyzing the mineralogy and textures of surface samples, along with skeletal contents, and C, O and S isotopes variations. The δ13C values of aragonitic bivalve shells and non-skeletal carbonate from some surface muds (1‰ to ?3.7‰ V-PDB) suggest that carbonate precipitated from ambient dissolved inorganic carbon, whereas fibrous aragonite cement and non-skeletal carbonate from other sites are highly depleted in 13C (down to ?47.6‰ V-PDB), suggesting formation via anaerobic oxidation of methane, characteristic of methane seepage environments. δ18O in most of the carbonates varies from +1.4‰ to +3.2‰ V-PDB, indicating that they formed from slightly modified seawater. Some non-skeletal carbonate grains from surface muds have lower δ18O values (?12.5‰ to ?8.2‰ V-PDB) reflecting the influence of 18O-depleted pore water. Size distribution of pyrite framboids (mean value: 3.1?μm) scattered within diatomaceous sinter suggests formation from anoxic-sulfidic bottom waters. δ34S in pyrite is of ?0.3‰ V-CDT compared to +46.6‰ V-CDT in barite, thus implying a fluid sulfate?sulfide fractionation of 21.3‰ that argues in favor of microbial sulfate reduction as the processes that mediated pyrite framboid formation, in a semi-closed system. Barite formation occurred through the mixing of reducing and Ba-rich seep fluids with a 34S-enriched sulfate pool that resulted from microbial sulfate reduction in a semi-closed system. The chemical composition of aragonite cement, barite and pyrite suggest mineral precipitation from modified seawater. Taken together, our data suggest that mineralization at the studied seep sites is controlled by the mixing of seawater with minor amounts of hydrothermal fluids, and oxygen-depleted conditions favoring anaerobic microbial processes.Nwadinigwe, C.A., Alumona, T.N., 2018. Assessment of n-alkanes and acyclic isoprenoids (geochemical markers) in crudes: A case study of Iraq and Niger delta, Nigeria. Egyptian Journal of Petroleum 27, 111-116. study was designed to determine the ratios of the isoprenoids and n-alkanes in an imported crude oil sample (Bassrah from Iraq) and four crude oil samples (Bodo, Bonny-Export, Escravos and Penningston) from the Niger Delta region of Nigeria to ascertain the levels of maturity and as an indicator of the depositional environment of the crudes. The physical properties of the crudes: viscosity, density and °API gravity were also determined. Fractionation of the crudes was done using a new approach coded NAASAR, (n-alkanes, asphaltenes, aromatics and resins) comprising urea adduction followed by gas chromatographic analyses (for n-alkanes), n-heptane precipitation (for asphaltenes) and column chromatography (for resins). Results showed °API gravities Bassrah 28.03°, Bodo 31.89°, Bonny-Export 33.8°, Escravos 33.8°, and Penningston 33.8° indicating that Escravos, Penningston and Bonny-Export crudes are light crudes while Bodo and Bassrah crudes are medium crudes. The n-alkanes profiles of the five crudes were determined by gas chromatography ranged from n-C8H18 to n-C40H82 with total weight percent n-alkane yield Bassrah 11.2, Bodo 47.41, Bonny-Export 32.47, Escravos 5.58, Penningston 30.75 were obtained by urea adduction. The pristane to phytane ratios were computed, Bassrah 1.51, Bodo 1.48, Bonny-Export 1.08, Escravos 1.01 and Penningston 2.41. Isoprenoids to n-alkane ratios Pr/n-C17 in the same order of the crudes were 0.85, 0.83, 0.67, 0.65, 0.95 while phytane to n-C18 ratios were 0.61, 0.55, 0.62, 0.61 and 0.43. The results established the increasing level of maturity as obtained from Pr/n-C17 ratio in the order: Penningston < Bassrah < Bodo < Bonny-Export < Escravos. The result of Pr/Ph ratios show the same trend in the level of maturity. Penningston crude with Pr/Ph ratio 2.41 shows that the crude is deposited in fluviomarine and coastal swamp environment while Bassrah, Bodo, Bonny-Export and Escravos crudes indicate aquatic depositional environment (anoxia) condition.Nzila, A., Ramirez, C.O., Musa, M.M., Sankara, S., Basheer, C., Li, Q.X., 2018. Pyrene biodegradation and proteomic analysis in Achromobacter xylosoxidans, PY4 strain. International Biodeterioration & Biodegradation 130, 40-47. aromatic hydrocarbons (PAHs) are environmental pollutants from incomplete combustion and petroleum products. As the molecular weight increases, PAHs become more recalcitrant to biodegradation. A bacterial strain capable of metabolizing the four fused aromatic ring PAH pyrene was isolated and characterized. The analysis of 16S rRNA gene revealed that it belongs to Achromobacter xylosoxidans species. A. xylosoxidans PY4 can utilize pyrene as the sole source of carbon. PY4 has a doubling time (dt) of less than 1 day when it grows in the presence of 1–5?mg?l?1 pyrene, a dt range similar to that of the most efficient pyrene biodegrading bacteria described so far. The optimal pyrene degradation conditions are at pH 7–9, 37–40?°C, and 0–2.5% NaCl. PY4 also utilizes salicylic acid, catechol, naphthalene, anthracene and phenanthrene. PY4 degrades more than 50% of 100?mg?l?1 of pyrene, within the first 15 days, at a rate of 0.069 day?1, R2?=?0.99. The metabolites include monohydroxypyrene, 1-methoxyl-2-H-benzo[h]chromene-2-carboxylic acid, 9,10-phenanthrenequinone, 1-methoxyl-trans-2′-carboxybenzalpyruvate, and dibutyl-phthalate. Up-expressed proteins in response to pyrene are involved in cell homeostasis, genetic information synthesis and storage, and chemical stress. Among these proteins are 4-hydroxyphenylpyruvate dioxygenase and homogentisate 1,2-dioxygenase, involved in the lower pyrene degradation pathway.Ocubalidet, S.G., Rimmer, S.M., Conder, J.A., 2018. Redox conditions associated with organic carbon accumulation in the Late Devonian New Albany Shale, west-central Kentucky, Illinois Basin. International Journal of Coal Geology 190, 42-55. affecting organic carbon accumulation in marine basins may include surface water productivity, enhanced preservation due to bottom-water anoxia, protection by and adsorption onto clays, and variations in sediment supply. In this study, geochemical proxies for the New Albany Shale of the Illinois Basin were examined for ten cores from the outcrop belt in west-central Kentucky in an attempt to evaluate redox conditions associated with organic carbon enrichment. In these cores, the Late Devonian New Albany Shale is represented by the Clegg Creek, Camp Run, Morgan Trail, and the Blocher members. Specifically, C-S relationships, degree of pyritization (DOPT), and C-S-Fe relationships along with redox sensitive trace elements (e.g., V and Mo) and ratios (Ni/Co, V/Cr, and V/(V+Ni)) were used to assess redox conditions. In addition, organic carbon to total phosphorus ratios (Corg/Ptot) were used to assess levels of paleoproductivity that were possibly enhanced by the productivity-anoxia-feedback mechanism. Results suggest variable bottom-water conditions existed during accumulation of the New Albany Shale of west-central Kentucky, including predominantly anoxic conditions for the Clegg Creek Member, dysoxic conditions for the Camp Run and Morgan Trail members, and dysoxic to oxic conditions for the Blocher Member. However, throughout deposition, all members exhibited some variability in redox conditions. Thus, overall, lowest oxygen levels were likely experienced during deposition of the Clegg Creek, followed by the Camp Run and Morgan Trail members. The Blocher Member was probably deposited under conditions closer to normal marine, yet still dysoxic at most times. High C/P ratios observed in these members suggest regeneration of P, enhanced productivity, and sequestration of organic carbon (as described by the productivity-anoxia feedback (PAF) mechanism) during anoxic periods. Variations in redox indications obtained from different proxies suggest that multiple parameters should be utilized rather than relying on a single proxy. Reasonably good agreement is seen between C-S, DOPT, C-S-Fe, and Mo levels; Ni/Co and V/Cr tend to agree well with each other, but suggest higher oxygen levels than the other proxies. Values for V/(V+Ni) tend to be an outlier, suggesting more anoxic (to euxinic) conditions compared to other proxies.Oh, Y.-K., Hwang, K.-R., Kim, C., Kim, J.R., Lee, J.-S., 2018. Recent developments and key barriers to advanced biofuels: A short review. Bioresource Technology 257, 320-333. are regarded as one of the most viable options for reduction of CO2 emissions in the transport sector. However, conventional plant-based biofuels (e.g., biodiesel, bioethanol)’s share of total transportation-fuel consumption in 2016 was very low, about 4%, due to several major limitations including shortage of raw materials, low CO2 mitigation effect, blending wall, and poor cost competitiveness. Advanced biofuels such as drop-in, microalgal, and electro biofuels, especially from inedible biomass, are considered to be a promising solution to the problem of how to cope with the growing biofuel demand. In this paper, recent developments in oxy-free hydrocarbon conversion via catalytic deoxygenation reactions, the selection of and lipid-content enhancement of oleaginous microalgae, electrochemical biofuel conversion, and the diversification of valuable products from biomass and intermediates are reviewed. The challenges and prospects for future development of eco-friendly and economically advanced biofuel production processes also are outlined herein.Olivier, N., Fara, E., Vennin, E., Bylund, K.G., Jenks, J.F., Escarguel, G., Stephen, D.A., Goudemand, N., Snyder, D., Thomazo, C., Brayard, A., 2018. Late Smithian microbial deposits and their lateral marine fossiliferous limestones (Early Triassic, Hurricane Cliffs, Utah, USA). Facies 64, Article 13. microbialite proliferations during the Early Triassic are usually explained by ecological relaxation and abnormal oceanic conditions. Most Early Triassic microbialites are described as single or multiple lithological units without detailed ecological information about lateral and coeval fossiliferous deposits. Exposed rocks along Workman Wash in the Hurricane Cliffs (southwestern Utah, USA) provide an opportunity to reconstruct the spatial relationships of late Smithian microbialites with adjacent and contemporaneous fossiliferous sediments. Microbialites deposited in an intertidal to subtidal interior platform are intercalated between inner tidal flat dolosiltstones and subtidal bioturbated fossiliferous limestones. Facies variations along these fossiliferous deposits and microbialites can be traced laterally over a few hundreds of meters. Preserved organisms reflect a moderately diversified assemblage, contemporaneous to the microbialite formation. The presence of such a fauna, including some stenohaline organisms (echinoderms), indicates that the development of these late Smithian microbial deposits occurred in normal-marine waters as a simple facies belt subject to relative sea-level changes. Based on this case study, the proliferation of microbialites cannot be considered as direct evidence for presumed harsh environmental conditions.Oppo, D., Hurst, A., 2018. Seepage rate of hydrothermally generated petroleum in East African Rift lakes: An example from Lake Tanganyika. Marine and Petroleum Geology 92, 149-159. Aperture Radar images provide temporal coverage of the oil seepage recurrence at Cape Kalumba, Lake Tanganyika. In combination with legacy seismic data, it has been possible to reconstruct the geological context that regulates seepage and estimate the oil seepage rates. Oil seepage is along fractures associated with the East Ubwari Faults, which in turn promote an active hydrothermal system that matures very shallow (10's m below the lake floor) oil-prone, less than 25 kyr old source rocks. Temporally consistent oil slick origin points are preferentially aligned E-W and SE-NW, and feed oil slicks on the lake surface. Pervasive seeps activity with significant emission rates, up to 449.39?m3?y-1, proves the presence of high-quality oil-prone source rocks and an active petroleum system that emits oil to form slicks. Hydrothermally-driven source rock maturation occurring at very shallow depth creates a narrow depth-window for conventional trapping of oil. Elsewhere in the lakes of the East African Rift, where similar hydrothermal systems occur, oil slicks may only be indicative of active petroleum systems without the presence of conventional traps.Ortiz-Villanueva, E., Jaumot, J., Martínez, R., Navarro-Martín, L., Pi?a, B., Tauler, R., 2018. Assessment of endocrine disruptors effects on zebrafish (Danio rerio) embryos by untargeted LC-HRMS metabolomic analysis. Science of The Total Environment 635, 156-166. A (BPA), perfluorooctane sulfonate (PFOS), and tributyltin (TBT) are emerging endocrine disruptors (EDCs) with still poorly defined mechanisms of toxicity and metabolic effects in aquatic organisms. We used an untargeted liquid chromatography-high resolution mass spectrometry (LC-HRMS) metabolomic approach to study the effects of sub-lethal doses of these three EDCs on the metabolic profiles of zebrafish embryos exposed from 48 to 120 hpf (hours post fertilization). Advanced chemometric data analysis methods were used to reveal effects on the subjacent regulatory pathways. EDC treatments induced changes in concentrations of about 50 metabolites for TBT and BPA, and of 25 metabolites for PFOS. The analysis of the corresponding metabolic changes suggested the presence of similar underlying zebrafish responses to BPA, TBT and PFOS affecting the metabolism of glycerophospholipids, amino acids, purines and 2-oxocarboxylic acids. We related the changes in glycerophospholipid metabolism to alterations in absorption of the yolk sack, the main source of nutrients (including lipids) for the developing embryo, linking the molecular markers with adverse phenotypic effects. We propose a general mode of action for all three chemical compounds, probably related to their already described interaction with the PPAR/RXR complex, combined with specific effects on different signaling pathways resulting in particular alterations in the zebrafish embryos metabolism.Osselin, F., Nightingale, M., Hearn, G., Kloppmann, W., Gaucher, E., Clarkson, C.R., Mayer, B., 2018. Quantifying the extent of flowback of hydraulic fracturing fluids using chemical and isotopic tracer approaches. Applied Geochemistry 93, 20-29. fracturing technologies have facilitated the rapid development of shale gas and other unconventional hydrocarbon resources throughout the world. Following hydraulic fracturing operations, a large quantity of water flows back to the surface. Understanding the provenance and composition of this returned water is therefore of paramount importance in order to optimize the recycling and reuse of the millions of litres of wastewater generated by hydraulic fracturing and to reduce freshwater consumption. Here we report flowback and produced fluids data obtained from a horizontal well in a low permeability reservoir within the Montney formation in Alberta, Canada. The reservoir was fractured with a mixture of nitrogen and water and the returned water was sampled 24 times during the first week of flowback and once after more than one year of production. The samples were analyzed for concentrations of major ions and for the stable isotope composition of water. The TDS (total dissolved solids) of the samples increased rapidly from 395?mg/L for the injected water to 50,000?mg/L after two days and 96,000?mg/L at the end of the first week of flowback. At the same time, δ2H values increased from ?142‰ to ?113‰ and δ18O values increased from ?18.3‰ to ?9.8‰. After more than one year, TDS reached 204,000?mg/L while δ2H and δ18O values further increased to ?68‰ and + 2.7‰. The salinity of the returned water is shown to be the result of the mixing between the highly saline formation water initially present in the reservoir before hydraulic fracturing, with the fresh water used for hydraulic fracturing. The presented mathematical model allows the calculation of the amount of fracturing fluid recovered as well as the quantity of saline formation water produced and reveals that most of the injected water is imbibed in the host rock of the producing formation. After a week of flowback, only 18% of the injected water had been recovered, while the recovery of fracturing fluids after 14.5 months is estimated at 36% of the total volume injected.Pacella, S.R., Brown, C.A., Waldbusser, G.G., Labiosa, R.G., Hales, B., 2018. Seagrass habitat metabolism increases short-term extremes and long-term offset of CO2 under future ocean acidification. Proceedings of the National Academy of Sciences 115, 3870-3875.: The impacts of ocean acidification in nearshore estuarine environments remain poorly characterized, despite these areas being some of the most ecologically important habitats in the global ocean. Here, we quantify how rising atmospheric CO2 from the years 1765 to 2100 alters high-frequency carbonate chemistry dynamics in an estuarine seagrass habitat. We find that increasing anthropogenic carbon reduces the ability of the system to buffer natural extremes in CO2. This reduced buffering capacity leads to preferential amplification of naturally extreme low pH and high pCO2(s.w.) events above changes in average conditions, which outpace rates published for atmospheric and open-ocean CO2 change. Seagrass habitat metabolism drives these short-term extreme events, yet ultimately reduces organismal exposure to harmful conditions in future high-CO2 scenarios.Abstract: The role of rising atmospheric CO2 in modulating estuarine carbonate system dynamics remains poorly characterized, likely due to myriad processes driving the complex chemistry in these habitats. We reconstructed the full carbonate system of an estuarine seagrass habitat for a summer period of 2.5 months utilizing a combination of time-series observations and mechanistic modeling, and quantified the roles of aerobic metabolism, mixing, and gas exchange in the observed dynamics. The anthropogenic CO2 burden in the habitat was estimated for the years 1765–2100 to quantify changes in observed high-frequency carbonate chemistry dynamics. The addition of anthropogenic CO2 alters the thermodynamic buffer factors (e.g., the Revelle factor) of the carbonate system, decreasing the seagrass habitat’s ability to buffer natural carbonate system fluctuations. As a result, the most harmful carbonate system indices for many estuarine organisms [minimum pHT, minimum Ωarag, and maximum pCO2(s.w.)] change up to 1.8×, 2.3×, and 1.5× more rapidly than the medians for each parameter, respectively. In this system, the relative benefits of the seagrass habitat in locally mitigating ocean acidification increase with the higher atmospheric CO2 levels predicted toward 2100. Presently, however, these mitigating effects are mixed due to intense diel cycling of CO2 driven by aerobic metabolism. This study provides estimates of how high-frequency pHT, Ωarag, and pCO2(s.w.) dynamics are altered by rising atmospheric CO2 in an estuarine habitat, and highlights nonlinear responses of coastal carbonate parameters to ocean acidification relevant for water quality management.Page, D.P., 2018. A candidate methane-clathrate destabilisation event on Mars: A model for sub-millennial-scale climatic change on Earth. Gondwana Research 59, 43-56. explosion of Siberian permafrost-mounds over the last three years questions whether this new phenomenon is the first sign of cascading release under climatic warming. Identical mounds occur in their millions on Mars but are uniformly interpreted as ancient volcanic structures, a geomorphic paradigm whose geological basis continues to escape objective observation. Here I show that thousands of Mars' mounds have recently exploded onto overlying aeolian dunes and are thus active and climatogenic, the time-lag between formation and synchronous explosion naturally explained by a trigger of climatic origin. Time-transgressive, mass explosion of a multi-billion-year-aged source has no parallel in rock-forming processes and points to regional-scale mobilisation of volatiles, this abrupt destabilisation event having immediate implications for hypothesised cascading releases from terrestrial clathrate reservoirs. Whether the Siberian explosions are new, or simply newly discovered, is uncertain but their spatial density is 20,000 times lower than on Mars, inconsistent with ongoing, multi-millennial-scale process. We should therefore consider the possibility that they are just beginning and, irrespective of volatile involved, we now have a scaleable example of how they might end. Were the clathrates of the East Siberian Arctic Shelf to degas on the density and frequency of Mars, then the entire reservoir would be depleted and unstoppable runaway warming initiated.Palazzotto, E., Weber, T., 2018. Omics and multi-omics approaches to study the biosynthesis of secondary metabolites in microorganisms. Current Opinion in Microbiology 45, 109-116. products produced by microorganisms represent the main source of bioactive molecules. The development of high-throughput (omics) techniques have importantly contributed to the renaissance of new antibiotic discovery increasing our understanding of complex mechanisms controlling the expression of biosynthetic gene clusters (BGCs) encoding secondary metabolites. In this context this review highlights recent progress in the use and integration of ‘omics’ approaches with focuses on genomics, transcriptomics, proteomics metabolomics meta-omics and combined omics as powerful strategy to discover new antibiotics.Pan, L., Wang, Y., Hu, H., Li, X., Liu, J., Guan, L., Tian, W., Wang, X., Li, Y., Wu, M., 2018. 3D self-assembly synthesis of hierarchical porous carbon from petroleum asphalt for supercapacitors. Carbon 134, 345-353. facile and scalable three-dimensional self-assembly template synthesis of hierarchical porous carbon method is developed. During the synthesis, KCl with face-centered cubic crystal is adopted to guide the growth of 3D porous carbon networks. Remarkably, the intimate interconnect porous feature not only significantly speeds up the electron transfer via shortened ion diffusion distance, but also exposes the electrochemically accessible active sites through ultrahigh surface area up to 3581?m2?g?1. As electrodes for button type supercapacitors, the HPC electrode shows a high capacitance of 277?F?g?1 at 0.05?A?g?1, superior rate performance of 194?F?g?1 at 20?A?g?1 and excellent cyclic stability of 95.1% after 10000 charge and discharge cycles at 2?A?g?1 in 6?M KOH electrolyte. Furthermore, the HPC based symmetric supercapacitors possess high specific energy density of 14.2 Wh kg?1 at a power density of 445?W?kg?1 operated in the wide voltage range of 1.8?V in the Na2SO4 electrolyte. This work opens up a facile way for efficient and scaled-up production of low-cost electrode materials with high performance for other energy storage devices.Panagiotopoulos, C., Pujo Pay, M., Benavides, M., Van Wambeke, F., Sempéré, R., 2018. The composition and distribution of labile dissolved organic matter across the south west Pacific. Biogeosciences Discussions 2018, 1-30. distribution and dynamics of dissolved organic carbon (DOC) and dissolved combined neutral sugars (DCNS) were studied across an increasing oligotrophic gradient (?18 to ?22°?N latitude) spanning from the Melanesian Archipelago (MA) area to the western part of the south Pacific gyre (WGY), in austral summer, as a part of the OUTPACE project. Our results showed DOC and DCNS concentrations exhibited little differences among the MA and WGY areas (0–200?m: 55–78??MC for DOC and 1.5–2??MC for DCNS), however, a deeper penetration of DOC was noticeable at 150?m depth at the WGY area. This finding was also reflected to the DOC and semi-labile DOC (DOCSL) stocks values (integration 0–200?m) for which we found higher values in the WGY than the MA area. The high excess DOCSL measured in WGY was characterized by a high residence time (130?±?31 days (n?=?3)) about three times higher than the MA region (Tr?=?40?±?7 days (n?=?8)) suggesting an accumulation of the semi-labile DOM in the surface waters of WGY. DCNS yields (DCNS-C x DOC?1?%) also followed this pattern with higher values recorded in the WGY (3.2?±?1.3?%) than MA (2.8?±?0.8?%) highlighting the presence of semi-labile dissolved organic material (DOM) in the form of polysaccharides. These polysaccharides also exhibited a higher residence time in WGY (Tr?=?8?±?4 days, n?=?3) than in MA (Tr?=?3?±?1days, n?=?8) suggesting that this DCNS pool persists longer in the surface waters of the WGY. The accumulation of DOCSL in the surface waters of WGY is probably due to the very slow bacterial degradation due to nutrient limitation indicating that biologically produced DOC can be stored in the euphotic layer for a very long period.Panfilova, M.A., Karaev, V.Y., Guo, J., 2018. Oil slick observation at low incidence angles in Ku‐band. Journal of Geophysical Research: Oceans 123, 1924-1936. the 20 April 2010 the oil platform Deep Water Horizon in the Gulf of Mexico suffered an explosion during the final phases of drilling an exploratory well. As a result, an oil film covered the sea surface area of several thousand square kilometers. In the present paper the data of the Ku‐band Precipitation Radar, which operates at low incidence angles, were used to explore the oil spill event. The two‐scale model of the scattering surface was used to describe radar backscatter from the sea surface. The algorithm for retrieval of normalized radar cross section at nadir and the total slope variance of large‐scale waves compared to the wavelength of electromagnetic wave (22 mm) was developed for the Precipitation Radar swath. It is shown that measurements at low incidence angles can be used for oil spill detection. This is the first time that the dependence of mean square slope of large‐scale waves on wind speed has been obtained for oil slicks from Ku‐band data, and compared to mean square slope obtained by Cox and Munk from optical data. Paquola, A.C.M., Asif, H., Pereira, C.A.d.B., Feltes, B.C., Bonatto, D., Lima, W.C., Menck, C.F.M., 2018. Horizontal gene transfer building prokaryote genomes: Genes related to exchange between cell and environment are frequently transferred. Journal of Molecular Evolution 86, 190-203. gene transfer (HGT) has a major impact on the evolution of prokaryotic genomes, as it allows genes evolved in different contexts to be combined in a single genome, greatly enhancing the ways evolving organisms can explore the gene content space and adapt to the environment. A systematic analysis of HGT in a large number of genomes is of key importance in understanding the impact of HGT in the evolution of prokaryotes. We developed a method for the detection of genes that potentially originated by HGT based on the comparison of BLAST scores between homologous genes to 16S rRNA-based phylogenetic distances between the involved organisms. The approach was applied to 697 prokaryote genomes and estimated that in average approximately 15% of the genes in prokaryote genomes originated by HGT, with a clear correlation between the proportion of predicted HGT genes and the size of the genome. The methodology was strongly supported by evolutionary relationships, as tested by the direct phylogenetic reconstruction of many of the HGT candidates. Studies performed with Escherichia coli W3110 genome clearly show that HGT proteins have fewer interactions when compared to those predicted as vertical inherited, an indication that the number of protein partners imposes limitations to horizontal transfer. A detailed functional classification confirms that genes related to protein translation are vertically inherited, whereas interestingly, transport and binding proteins are strongly enriched among HGT genes. Because these genes are related to the cell exchange with their environment, their transfer most likely contributed to successful adaptation throughout evolution.Park, T., Lee, J.Y., Kwon, T.-H., 2018. Effect of pore size distribution on dissociation temperature depression and phase boundary shift of gas hydrate in various fine-grained sediments. Energy & Fuels 32, 5321-5330. in small, confined pores has a pronounced effect on the depression of the dissociation temperature of gas hydrates, known as the Gibbs–Thomson effect. However, this effect remains poorly understood in natural fine-grained sediments with wide pore size distributions. This study investigated the effect of pore size distributions of fine-grained sediments on the dissociation temperature of a gas hydrate. A gas hydrate was synthesized under partially water-saturated conditions in nanosized silica gels and in various natural fine-grained sediment samples, including sand, silt, diatoms, a diatom–sand mixture, and clayey sediment. The synthesized hydrate samples were thermally dissociated under isochoric conditions, while the melting temperature depression and the shifted phase boundaries were monitored. We observed a dissociation temperature depression of approximately 0.1–0.3 °C in silt, 0.2–0.4 °C in the diatom sample, and 1.2–1.5 °C in clayey silt, while no temperature depression was observed in sand. In a particular case of diatom–sand mixture, the dual porosity condition with the submicron-scale internal pores of diatoms and the macropores of sands rendered dual phase boundaries, one with an ～0.4 °C temperature depression and one with no depression, respectively. Despite the wide ranges of pore size, gas hydrates were preferentially formed in smaller pores, which comprise less than 40% of the cumulative pore volumes. This was because the initial water loci exacerbated the Gibbs–Thomson effect in partially water-saturated conditions. Our results provide clear experimental evidence on and novel insights into the effect of pore size distributions of fine-grained sediments on the dissociation behavior and phase boundaries of gas hydrates, both in the presence of free gas and in water-limiting conditions that exhibit a considerable Gibbs–Thomson effect.Pauk, V., Lemr, K., 2018. Forensic applications of supercritical fluid chromatography – mass spectrometry. Journal of Chromatography B 1086, 184-196. of supercritical fluid chromatography with mass spectrometric detection made in the field of forensic science during the last decade are reviewed. The main topics include analysis of traditional drugs of abuse (e.g. cannabis, methamphetamine) as well as new psychoactive substances (synthetic cannabinoids, cathinones and phenethylamines), doping agents (anabolic steroids, stimulants, diuretics, analgesics etc.) and chemical warfare agents. Control of food authenticity, detection of adulteration and identification of toxic substances in food are also pointed out. Main aspects of an analytical workflow, such as sample preparation, separation and detection are discussed. A special attention is paid to the performance characteristics and validation parameters of supercritical fluid chromatography-mass spectrometric methods in comparison with other separation techniques.Pedersen, E.P., Michelsen, A., Elberling, B., 2018. In situ CH4 oxidation inhibition and 13CH4 labeling reveal methane oxidation and emission patterns in a subarctic heath ecosystem. Biogeochemistry 138, 197-213. methane (CH4) flux across the ecosystem-atmosphere boundary is governed by two counteracting processes, CH4 oxidation and production. Recent research on CH4 cycling has focused on net CH4 fluxes, however, the separate processes of CH4 oxidation and production may vary at local scales and respond differently to environmental change. Here, we separate CH4 oxidation and production, measured as emission, in situ using CH4 oxidation inhibition combined with a novel in situ 13CH4 labeling experiment to determine the rate of soil oxidation of atmospheric CH4. The study was conducted in a subarctic heath ecosystem with three characteristic plant community types: moist mixed species heath, dry Carex-dominated heath, and wet Eriophorum-dominated fen. We further explored the projected climate change effects of increased temperature and enhanced leaf litter input. The CH4 oxidation inhibition experiment revealed significant potential CH4 emission despite net CH4 uptake. Total CH4 oxidation and potential CH4 emission rates differed significantly between plant communities, demonstrating high local-scale variation in CH4 fluxes. Climate treatments did not affect CH4 oxidation rates, however, warming tended to increase potential CH4 emission, indicating that climate change may affect oxidation and production rates asymmetrically. Near-surface soil oxidation of atmospheric CH4 was successfully traced using 13C stable isotope labeling in situ. CH4 oxidation rates ranged widely, yet preliminarily suggested some degree of substrate limitation. Accounting for the local-scale variation in CH4 fluxes and the relative importance of the separate processes of CH4 oxidation and production will contribute importantly to predicting changes in landscape-scale CH4 budgets and climate feedbacks.Pellerin, A., Wenk, C.B., Halevy, I., Wing, B.A., 2018. Sulfur isotope fractionation by sulfate-reducing microbes can reflect past physiology. Environmental Science & Technology 52, 4013-4022. (S) isotope fractionation by sulfate-reducing microorganisms is a direct manifestation of their respiratory metabolism. This fractionation is apparent in the substrate (sulfate) and waste (sulfide) produced. The sulfate-reducing metabolism responds to variability in the local environment, with the response determined by the underlying genotype, resulting in the expression of an “isotope phenotype”. Sulfur isotope phenotypes have been used as a diagnostic tool for the metabolic activity of sulfate-reducing microorganisms in the environment. Our experiments with Desulfovibrio vulgaris Hildenborough (DvH) grown in batch culture suggest that the S isotope phenotype of sulfate respiring microbes may lag environmental changes on time scales that are longer than generational. When inocula from different phases of growth are assayed under the same environmental conditions, we observed that DvH exhibited different net apparent fractionations of up to ?9‰. The magnitude of fractionation was weakly correlated with physiological parameters but was strongly correlated to the age of the initial inoculum. The S isotope fractionation observed between sulfate and sulfide showed a positive correlation with respiration rate, contradicting the well-described negative dependence of fractionation on respiration rate. Quantitative modeling of S isotope fractionation shows that either a large increase (≈50×) in the abundance of sulfate adenylyl transferase (Sat) or a smaller increase in sulfate transport proteins (≈2×) is sufficient to account for the change in fractionation associated with past physiology. Temporal transcriptomic studies with DvH imply that expression of sulfate permeases doubles over the transition from early exponential to early stationary phase, lending support to the transport hypothesis proposed here. As it is apparently maintained for multiple generations (≈1–6) of subsequent growth in the assay environment, we suggest that this fractionation effect acts as a sort of isotopic “memory” of a previous physiological and environmental state. Whatever its root cause, this physiological hysteresis effect can explain variations in fractionations observed in many environments. It may also enable new insights into life at energetic limits, especially if its historical footprint extends deeper than generational.Peng, W., Hu, G., Feng, Z., Liu, D., Wang, Y., Lv, Y., Zhao, R., 2018. Origin of Paleogene natural gases and discussion of abnormal carbon isotopic composition of heavy alkanes in the Liaohe Basin, NE China. Marine and Petroleum Geology 92, 670-684. components, stable isotopic compositions and light hydrocarbons are investigated to determine the origin and isotopic anomalies of natural gases in the Paleogene of the Liaohe Basin of northeastern China. Natural gas in Paleogene is dominated by alkanes. Dry gas predominantly occurs in the shallow layers of the Paleogene having burial depth less than 1900 m, specifically in the Dongying Formation (E3d) and the first member of the Shahejie Formation (E3s1); wet gas mostly occurs in the deep layer, primarily in the third member of the Shahejie Formation (E2s3). The relative content of methyl cyclohexane in the Western Depression (WD) of the Liaohe Basin is less than that in the Eastern Depression (ED), while the relative contents of alkanes in the C5-7 light hydrocarbons of the WD are higher than those of the ED. Natural gases are of multiple origins, including microbial gas (gas generated by microbial action on immature source rock), coal-derived gas (gas generated by humic source rock) and oil-associated gas (gas generated by sapropelic source rock). In the WD, oil-associated gas is dominant, while in the ED, coal-derived gas dominates. The abnormally heavy carbon isotopic composition of Paleogene heavy alkanes is primarily caused by bacteria oxidation, rather than by being mixed with deep source gas. Natural gases from the E3d and E3s1 suffer the most severe bacterial oxidation, the intensity of which gradually declines with the increasing depth. The low average heptane and isoheptane values indicate that natural gases are mostly generated in the early mature stage of the source rock. Natural gases in E2s3 of the WD are mainly derived from E2s4 and E2s3 source rocks, while those of E3d and E3s1 are predominantly generated by E2s3 source rock. Gases in the ED come principally from E2s3 source rock.Pennetta de Oliveira, L., Gumfekar, S.P., Lopes Motta, F., Soares, J.B.P., 2018. Dewatering of oil sands tailings with novel chitosan-based flocculants. Energy & Fuels 32, 5271-5278. fine tailings need to be dewatered to reduce the environmental impact caused by oil sands extraction. Polymer flocculants are commonly used to accelerate this process. In this work, we modified chitosan, a naturally occurring biopolymer, with 3-chloro-2-hydroxypropyltrimethylammonium chloride (Chito-CTA) and also grafted polyacrylamide to chitosan (Chito-g-PAM). We compared the dewatering performance of these two flocculants with that of a commercial cationic polyacrylamide (C-PAM). Chito-CTA and Chito-g-PAM dewatered tailings at rates of 18.27 and 20.72 m/h, respectively. The dewatering ability of Chito-CTA and Chito-g-PAM, measured in terms of capillary suction time (CST), was below 10 s, whereas the value for C-PAM was 82.3 s at optimum dosage. The turbidity of the supernatant obtained after flocculation with Chito-CTA or Chito-g-PAM was below 10 NTU, while C-PAM produced turbid supernatants. We studied the effect of flocculant microstructure on the specific resistance to filtration of the sediments. Chito-g-PAM produced sediments with the lowest resistance, 2.99 × 1012 m/kg, while C-PAM’s sediments had a much higher resistance of 40.26 × 1012 m/kg. We also used the focused beam reflectance measurement technique to determine floc size evolution, floc stability, and time required to induce floc formation. Our results indicate that chitosan-based polymers may be successfully used to treat oil sands mature fine tailings.Permanyer, A., Martín-Martín, J.D., Kihle, J., Márquez, G., Marfil, R., 2018. Oil shows geochemistry and fluid inclusion thermometry of Mid Cretaceous carbonates from the eastern Basque Cantabrian Basin (N Spain). Marine and Petroleum Geology 92, 255-269. liquid and solid hydrocarbons are common in Cretaceous carbonate exposures throughout the Basque Cantabrian Basin (N Spain). This study investigates the oil shows that appear in the upper Albian-lower Cenomanian reefal limestones cropping out in the eastern margin of the basin in order to assess potential source rocks and common characteristics with other oil occurrences in the basin. Specifically, the study focuses on (i) the petrography and fluid inclusion thermometry of the host rock and cements, and (ii) geochemistry of the hydrocarbons including biomarkers and isotopes. Geochemistry results indicate that the studied oils, in a way similar to previously reported hydrocarbons from the eastern Basque Cantabrian Basin, were generated from marine carbonate source rocks deposited in a hypersaline environment. However, their isotopic signatures are notably different, and thus discard a common source rock. Moreover, the studied oils are notably different from those reported elsewhere in the basin, both in the western and northern parts. The petrography of the calcite cements and the fluid inclusion thermometry suggests a scenario of condensates to light oils HC migration trapped in burial calcite cements at a minimum temperature of 174?°C. The generation, migration and entrapment of these oils took likely place between Turonian and Campanian time in close association with the elevated heat flow resulting from the rift extension. Following this stage, a second entrapment of heavy to asphaltene-rich oils occurred at 72?°C, likely during the Late Cretaceous to early Cenozoic uplift related to the early stages of inversion of the Basque Cantabrian Basin. The elevated temperature of the oil entrapment suggests the occurrence of abnormal geothermal gradients in the eastern Basque Cantabrian Basin during the middle Late Cretaceous, which is ultimately associated with the opening of the Bay of Biscay.Pessi, I.S., Lara, Y., Durieu, B., Maalouf, P.d.C., Verleyen, E., Wilmotte, A., 2018. Community structure and distribution of benthic cyanobacteria in Antarctic lacustrine microbial mats. FEMS Microbiology Ecology 94, Article fiy042. terrestrial Antarctic Realm has recently been divided into 16 Antarctic Conservation Biogeographic Regions (ACBRs) based on environmental properties and the distribution of biota. Despite their prominent role in the primary production and nutrient cycling in Antarctic lakes, cyanobacteria were only poorly represented in the biological dataset used to delineate these ACBRs. Here, we provide a first high-throughput sequencing insight into the spatial distribution of benthic cyanobacterial communities in Antarctic lakes located in four distinct, geographically distant ACBRs and covering a range of limnological conditions. Cyanobacterial community structure differed between saline and freshwater lakes. No clear bioregionalization was observed, as clusters of community similarity encompassed lakes from distinct ACBRs. Most phylotypes (77.0%) were related to cyanobacterial lineages (defined at ≥99.0% 16S rRNA gene sequence similarity) restricted to the cold biosphere, including lineages potentially endemic to Antarctica (55.4%). The latter were generally rare and restricted to a small number of lakes, while more ubiquitous phylotypes were generally abundant and present in different ACBRs. These results point to a widespread distribution of some cosmopolitan cyanobacterial phylotypes across the different Antarctic ice-free regions, but also suggest the existence of dispersal barriers both within and between Antarctica and the other continents.Peters, K.E., Burnham, A.K., Walters, C.C., Schenk, O., 2018. Guidelines for kinetic input to petroleum system models from open-system pyrolysis. Marine and Petroleum Geology 92, 979-986. basin and petroleum system </topics/earth-and-planetary-sciences/petroleum-system> models (BPSM) require accurate kinetic parameters for the conversion of source-rock kerogen </topics/earth-and-planetary-sciences/kerogen> to petroleum </topics/earth-and-planetary-sciences/petroleum>. The purpose of this paper is to dispel widespread uncertainty about kinetic input to BPSM by providing guidelines based on interpretation of previously published data for 81 worldwide source rocks containing various kerogen types.? Kinetic response is unrelated to kerogen type as defined by Rock-Eval pyrolysis hydrogen index. Default kinetics in BPSM software may differ from that for the same kerogen type in different study areas. Use default kinetics with caution when appropriate measured kinetics are unavailable.? Measure kinetic parameters using thermally immature equivalents of the source rock, which may require multiple samples because kerogen kinetics can vary laterally and vertically in each source rock.? Descriptions of depositional environment are insufficient to define kerogen type or kinetic response in different basins.? Optimize multiple-run programmed pyrolysis results for both the activation energy (Ea) and frequency factor (A). Assuming a universal value of A rather than optimizing both Ea and A can yield temperature errors of 20 °C or more when extrapolated to geologic time.? Alternative kinetic models to calculate vitrinite reflectance (Ro) may be more accurate than Easy%Ro for BPSM calibration. In the Aurora-1 and Inigok-1 wells in Alaska, Basin%Ro and Easy%RoDL, more accurately replicates the dogleg in vitrinite reflectance versus depth commonly observed in wells at depths corresponding to ～0.7–1.0% Ro.Petersen, H.I., Hertle, M., 2018. A review of the coaly source rocks and generated petroleums in the Danish North Sea: An underexplored middle Jurassic petroleum system? Journal of Petroleum Geology 41, 135-154. paper reviews the Middle Jurassic petroleum system in the Danish Central Graben with a focus on source rock quality, fluid compositions and distributions, and the maturation and generation history. The North Sea including the Danish Central Graben is a mature oil province where the primary source rock is composed of Upper Jurassic – lowermost Cretaceous marine shales. Most of the shale‐sourced structures have been drilled and, to accommodate continued value creation, additional exploration opportunities are increasingly considered in E&P strategies. Triassic and Jurassic sandstone plays charged from coaly Middle Jurassic source rocks have proven to be economically viable in the North Sea. In the Danish‐Norwegian S?gne Basin, coal‐derived gas/condensate is produced from the Harald and Trym fields and oil from the Lulita field; the giant Culzean gas‐condensate field is under development in the UK Central North Sea; and in the Norwegian South Viking Graben, coal‐derived gas and gas‐condensate occur in several fields. The coaly source rock of the Middle Jurassic petroleum system in the greater North Sea is included in the Bryne/Lulu Formations (in Denmark), the Pentland Formation (in the UK), and the Sleipner and Hugin Formations in Norway. In the Danish Central Graben, the coal‐bearing unit is composed of coals, coaly shales and carbonaceous shales, has a regional distribution and can be mapped seismically as the ‘Coal Marker’. The coaly source rocks are primarily gas‐prone but the coals have an average Hydrogen Index value of c. 280 mg HC/g TOC and values above 300 mg HC/g TOC are not uncommon, which underpins the coals' capacity to generate liquid hydrocarbons (condensate and oil). The coal‐sourced liquids are differentiated from the common marine‐sourced oils by characteristic biomarker and isotope compositions, and in the Danish Central Graben are grouped into specific oil families composed of coal‐sourced oil and mixed oils with a significant coaly contribution. Similarly, the coal‐sourced gases are recognized by a normally heavier isotope signature and a relatively high dryness coefficient compared to oil‐associated gas derived from marine shales. The coal‐derived and mixed coaly gases are likewise assigned to well‐defined gas families. Coal‐derived liquids and gas discoveries and shows in Middle Jurassic strata suggest that the coaly Middle Jurassic petroleum system has a regional distribution. A 3D petroleum systems model was constructed covering the Danish Central Graben. The model shows that present‐day temperatures for the Middle Jurassic coal source rock ('Coal Marker') are relatively high (>150 °C) throughout most of the Danish Central Graben, and expulsion of hydrocarbons from the ‘Coal Marker’ was initiated in Late Jurassic time in the deep Tail End Graben. In the Cretaceous, the area of mature coaly source rocks expanded, and at present day nearly the whole area is mature. Hydrocarbon expulsion rates were low in the Paleocene to Late Oligocene, followed by significant expulsion in the Miocene up to the present day. High Middle Jurassic reservoir temperatures prevent biodegradation.Petrick, B., McClymont, E.L., Littler, K., Rosell-Melé, A., Clarkson, M.O., Maslin, M., R?hl, U., Shevenell, A.E., Pancost, R.D., 2018. Oceanographic and climatic evolution of the southeastern subtropical Atlantic over the last 3.5 Ma. Earth and Planetary Science Letters 492, 12-21. southeast Atlantic Ocean is dominated by two major oceanic systems: the Benguela Upwelling System, one of the world's most productive coastal upwelling cells and the Agulhas Leakage, which is important for transferring warm salty water from the Indian Ocean to the Atlantic Ocean. Here, we present a multi-proxy record of marine sediments from ODP Site 1087. We reconstruct sea surface temperatures (U37K′ and TEX86 indices), marine primary productivity (total chlorin and alkenone mass accumulation rates), and terrestrial inputs derived from southern Africa (Ti/Al and Ca/Ti via XRF scanning) to understand the evolution of the Southeast Atlantic Ocean since the late Pliocene. In the late Pliocene and early Pleistocene, ODP Site 1087 was situated within the Benguela Upwelling System, which was displaced southwards relative to present. We recognize a series of events in the proxy records at 3.3, 3.0, 2.2, 1.5, 0.9 and 0.6 Ma, which are interpreted to reflect a combination of changes in the location of major global wind and oceanic systems and local variations in the strength and/or position of the winds, which influence nutrient availability. Although there is a temporary SST cooling observed around the initiation of Northern Hemisphere glaciation (iNHG), proxy records from ODP Site 1087 show no clear climatic transition around 2.7 Ma but instead most of the changes occur before this time. This observation is significant because it has been previously suggested that there should be a change in the location and/or strength of upwelling associated with this climate transition. Rather, the main shifts at ODP Site 1087 occur at ca. 0.9 Ma and 0.6 Ma, associated with the early mid-Pleistocene transition (EMPT), with a clear loss of the previous upwelling-dominated regime. This observation raises the possibility that reorganisation of southeast Atlantic Ocean circulation towards modern conditions was tightly linked to the EMPT, but not to earlier climate transitions.Phan, T.T., Paukert Vankeuren, A.N., Hakala, J.A., 2018. Role of water?rock interaction in the geochemical evolution of Marcellus Shale produced waters. International Journal of Coal Geology 191, 95-111. of geochemical processes that occur during hydraulic fracturing of shale resources for natural gas recovery can provide insight into in situ mineral precipitation and dissolution reactions that affect shale pore and fracture networks, and ultimately the ability to recover natural gas. Measurement of dissolved chemical species in produced waters, which serve as indicators of water-rock reactions in the reservoir, is one approach for monitoring subsurface geochemistry. However, an ability to distinguish effects of water-rock reactions versus reservoir fluid mixing on chemical concentration and speciation in produced waters requires experimental investigation to better understand natural geochemical tracer behavior. In this study, we explored Li, Sr, and U as geochemical tracers of ion?exchange and mineral dissolution reactions occurring during a series of flow-through laboratory experiments designed to evaluate mineral reactions occurring in shale reacted with hydraulic fracturing fluid (HFF). The experiments, reported in detail in a separate study (Paukert Vankeuren et al., 2017), were designed to emulate shut-in conditions (period after hydraulic fracturing but before production when HFF remains in the reservoir to allow for opening of new fractures for hydrocarbon recovery) for Marcellus Shale undergoing hydraulic fracturing in southwestern Pennsylvania, USA. In the companion study presented here, effluent samples from the core flood experiments were analyzed for changes in Li isotopes (δ7Li), radiogenic Sr isotopes (εSrSW), and U concentration as possible unique geochemical tracers to indicate water-rock reaction. Experimental and reactive transport modeling results demonstrated that the peak of U in experimental effluents is derived from dissolution of U-containing calcite, which may explain the pulse of U observed in produced water collected from hydraulically fractured Marcellus Shale on the first day of flowback. Experimental results also showed that changes in δ7Li values and εSrSW from the flow-through experiments differ from values measured in a time series of produced waters from Marcellus Shale gas wells. Thus, although ion?exchange and mineral dissolution and precipitation reactions result in an observable change in Sr isotope signals in laboratory experiments, this change may not be identifiable in produced waters in the field due to complications associated with geologic heterogeneity and overprinting of other signals such as fluid mixing and transport. While U shows some promise as a tracer of HFF-shale reactions, particularly carbonate dissolution, it may be necessary to continue searching for other tracers present in produced waters to aid in elucidating in situ water-rock reactions of interest.Phelps, A.S., Hofmann, M.H., Hart, B.S., 2018. Facies and stratigraphic architecture of the Upper Devonian–Lower Mississippian Sappington Formation, southwestern Montana: A potential outcrop analog for the Bakken Formation. American Association of Petroleum Geologists Bulletin 102, 793-815. study describes the sedimentology and stratigraphy of the Devonian–Mississippian Sappington Formation in exceptional outcrop exposures in southwestern Montana. The goal was to assess the extent to which these outcrops could be used to define stratigraphic heterogeneity of time-equivalent Bakken Formation reservoir and source rocks of the Williston Basin.Facies analysis of the Sappington Formation shows three depositional sequences deposited along a storm- and wave-influenced coastline. The first sequence encompasses the lower Sappington shale, dominated by organic-rich mudstones that represent an anoxic to dysoxic lower-shelf environment. The second sequence is marked by a basal transgressive surface and initial siltstone deposition. These siltstones are abruptly overlain by basinward-dipping, low-angle clinoforms (<1°) that represent a storm- and wave-influenced shoreface. Facies distributions along clinoforms change along depositional dip over approximately 17 km (～11 mi) from proximal to distal across the study area. The best reservoir facies are present in the upper foresets of these clinoforms. The upper shale of the Sappington Formation forms the lowest part of the third depositional sequence that continues into the overlying Lodgepole Limestone.The outcrop-based stratigraphy of the Sappington Formation provides insights into the scale of stratigraphic heterogeneity that is likely to be present in the time-equivalent Bakken Formation over the length of a typical approximately 3-km-long (～2-mi-long) horizontal well. Geosteering horizontal wells in the Bakken along bedding surfaces, that is, along gently dipping clinoforms, is likely to cause variations in rock properties from the toe to heel of a horizontal well.Phiri, Z., Everson, R.C., Neomagus, H.W.J.P., Engelbrecht, A.D., Wood, B.J., Nyangwa, B., 2018. Release of nitrogenous volatile species from South African bituminous coals during pyrolysis. Energy & Fuels 32, 4606-4616. influence of typical South African coal attributes on the release of nitrogen into the volatile stream during pyrolysis was studied by utilizing three bituminous coals. The majority of South African coals are characterized by high mineral matter and are rich in inertinite maceral. Pyrolysis was conducted in a bench-scale fluidized bed (FB) at 740–980 °C, and also in a drop-tube furnace (DTF) at 1000–1400 °C. Levels of nitrogenous species in the volatile stream in the form of NH3, HCN, and tar-N were determined. Nitrogen functional forms of tars released at low temperatures were predominantly distinguished by high levels of pyrrolic nitrogen, followed by pyridinic and quaternary nitrogen, respectively. Tars liberated at 740 °C possessed similar nitrogen functional form attributes as those of parent coals. However, an increase in pyrolysis temperature caused a gradual increase in quaternary nitrogen as well as a concurrent decrease in pyrrolic nitrogen and a concomitant subtle decrease in pyridinic nitrogen. The analysis of nitrogen in tars was only confined to tars extracted from the FB. Vitrinite-rich and/or high mineral matter coal released high yields of nitrogenous species into the volatile stream at low FB temperatures. A large amount of NH3 was released relative to HCN under FB pyrolysis conditions. However, more HCN was released than NH3 during DTF pyrolysis. Two coals, one characterized by high mineral matter and being rich in vitrinite, and the other distinguished by relatively low mineral matter and being rich in inertinite, behaved similarly by reaching respective peak amounts of NH3 yields at 820 °C under FB pyrolysis conditions. On the contrary, an opposite profile displaying a slump at 820 °C was observed for HCN yields from the two respective coals. The third coal, a high mineral matter and inertinite-rich coal, released high NH3 yields and simultaneously the least HCN yields at 740 °C. Under DTF experimental conditions, both NH3 and HCN steadily increased with temperature in all coals. The low mineral matter and inertinite-rich coal released high yields of total volatile-N from 1000 to 1270 °C, only to be surpassed by the vitrinite-rich/high mineral matter coal at 1400 °C. The inertinite-rich/high mineral matter coal released the least throughout the entire DTF temperature range. The total mineral matter content of the coals played a significant role toward the nitrogen product distribution. On the other hand, the total reactive macerals also influenced the emission of volatile species at 1130–1400 °C DTF temperature range. The yields and composition of the released nitrogenous species have been attributed to a combination of mineral matter content, petrographic properties of the parent coals, and the utilized conditions. Pyrolysis temperature, coal particle size, and residence time also play a significant role toward the yields and composition of the released nitrogenous species.Pi, X., Tian, L., Dai, H.-E., Qin, X., Cheng, L., Kuang, T., Sui, S.-F., Shen, J.-R., 2018. Unique organization of photosystem I–light-harvesting supercomplex revealed by cryo-EM from a red alga. Proceedings of the National Academy of Sciences 115, 4423-4428.: Photosystem I (PSI) is one of the most efficient nanophotochemical machines in nature. To adapt to various environments, photosynthetic organisms developed different PSI structure during evolution from prokaryotic cyanobacteria to higher plants. Red algae are one of the most primitive eukaryotic algae, and their photosynthetic apparatus represents a transitional state between cyanobacteria and eukaryotes. We determined two forms of the PSI-LHCR structure from a red alga by cryo-EM. Our results revealed unique features and energy transfer pathways in the red algal PSI supercomplex with LHCI (light-harvesting complex I), as well as its remarkable differences with those of cyanobacterial PSI and higher plant PSI-LHCI. These results provide important information for delineating the function and evolution of PSI from prokaryotic to eukaryotic photosynthetic organisms.Abstract: Photosystem I (PSI) is one of the two photosystems present in oxygenic photosynthetic organisms and functions to harvest and convert light energy into chemical energy in photosynthesis. In eukaryotic algae and higher plants, PSI consists of a core surrounded by variable species and numbers of light-harvesting complex (LHC)I proteins, forming a PSI-LHCI supercomplex. Here, we report cryo-EM structures of PSI-LHCR from the red alga Cyanidioschyzon merolae in two forms, one with three Lhcr subunits attached to the side, similar to that of higher plants, and the other with two additional Lhcr subunits attached to the opposite side, indicating an ancient form of PSI-LHCI. Furthermore, the red algal PSI core showed features of both cyanobacterial and higher plant PSI, suggesting an intermediate type during evolution from prokaryotes to eukaryotes. The structure of PsaO, existing in eukaryotic organisms, was identified in the PSI core and binds three chlorophylls a and may be important in harvesting energy and in mediating energy transfer from LHCII to the PSI core under state-2 conditions. Individual attaching sites of LHCRs with the core subunits were identified, and each Lhcr was found to contain 11 to 13 chlorophylls a and 5 zeaxanthins, which are apparently different from those of LHCs in plant PSI-LHCI. Together, our results reveal unique energy transfer pathways different from those of higher plant PSI-LHCI, its adaptation to the changing environment, and the possible changes of PSI-LHCI during evolution from prokaryotes to eukaryotes.Pillot, G., Frouin, E., Pasero, E., Godfroy, A., Combet-Blanc, Y., Davidson, S., Liebgott, P.-P., 2018. Specific enrichment of hyperthermophilic electroactive Archaea from deep-sea hydrothermal vent on electrically conductive support. Bioresource Technology 259, 304-311. more and more investigations are done to study hyperthermophilic exoelectrogenic communities from environments, none have been performed yet on deep-sea hydrothermal vent. Samples of black smoker chimney from Rainbow site on the Atlantic mid-oceanic ridge have been harvested for enriching exoelectrogens in microbial electrolysis cells under hyperthermophilic (80?°C) condition. Two enrichments were performed in a BioElectrochemical System specially designed: one from direct inoculation of crushed chimney and the other one from inoculation of a pre-cultivation on iron (III) oxide. In both experiments, a current production was observed from 2.4?A/m2 to 5.8?A/m2 with a set anode potential of ?0.110?V vs Ag/AgCl. Taxonomic affiliation of the exoelectrogen communities obtained on the electrode exhibited a specific enrichment of Archaea belonging to Thermococcales and Archeoglobales orders, even when both inocula were dominated by Bacteria.Piotrowski, P.K., Weggler, B.A., Yoxtheimer, D.A., Kelly, C.N., Barth-Naftilan, E., Saiers, J.E., Dorman, F.L., 2018. Elucidating environmental fingerprinting mechanisms of unconventional gas development through hydrocarbon analysis. Analytical Chemistry 90, 5466-5473. fracturing is an increasingly common technique for the extraction of natural gas entrapped in shale formations. This technique has been highly criticized due to the possibility of environmental contamination, underscoring the need for method development to identify chemical factors that could be utilized in point-source identification of environmental contamination events. Here, we utilize comprehensive two-dimensional gas chromatography (GC × GC) coupled to high-resolution time-of-flight (HRT) mass spectrometry, which offers a unique instrumental combination allowing for petroleomics hydrocarbon fingerprinting. Four flowback fluids from Marcellus shale gas wells in geographic proximity were analyzed for differentiating factors that could be exploited in environmental forensics investigations of shale gas impacts. Kendrick mass defect (KMD) plots of these flowback fluids illustrated well-to-well differences in heteroatomic substituted hydrocarbons, while GC × GC separations showed variance in cyclic hydrocarbons and polyaromatic hydrocarbons among the four wells. Additionally, generating plots that combine GC × GC separation with KMD established a novel data-rich visualization technique that further differentiated the samples.Pjevac, P., Meier, D., Markert, S., Hentschker, C., Schweder, T., Becher, D., Gruber-Vodicka, H., Richter, M., Bach, W., Amann, R., Meyerdierks, A., 2018. Metaproteogenomic profiling of microbial communities colonizing actively venting hydrothermal chimneys. Frontiers in Microbiology 9, 680. doi: 10.3389/fmicb.2018.00680. hydrothermal vent sites, chimneys consisting of sulfides, sulfates, and oxides are formed upon contact of reduced hydrothermal fluids with oxygenated seawater. The walls and surfaces of these chimneys are an important habitat for vent-associated microorganisms. We used community proteogenomics to investigate and compare the composition, metabolic potential and relative in situ protein abundance of microbial communities colonizing two actively venting hydrothermal chimneys from the Manus Basin back-arc spreading center (Papua New Guinea). We identified overlaps in the in situ functional profiles of both chimneys, despite differences in microbial community composition and venting regime. Carbon fixation on both chimneys seems to have been primarily mediated through the reverse tricarboxylic acid cycle and fueled by sulfur-oxidation, while the abundant metabolic potential for hydrogen oxidation and carbon fixation via the Calvin-Benson-Bassham cycle was hardly utilized. Notably, the highly diverse microbial community colonizing the analyzed black smoker chimney had a highly redundant metabolic potential. In contrast, the considerably less diverse community colonizing the diffusely venting chimney displayed a higher metabolic versatility. An increased diversity on the phylogenetic level is thus not directly linked to an increased metabolic diversity in microbial communities that colonize hydrothermal chimneys.Planavsky, N.J., Slack, J.F., Cannon, W.F., O'Connell, B., Isson, T.T., Asael, D., Jackson, J.C., Hardisty, D.S., Lyons, T.W., Bekker, A., 2018. Evidence for episodic oxygenation in a weakly redox-buffered deep mid-Proterozoic ocean. Chemical Geology 483, 581-594. the last two decades, popular opinion about prevailing conditions in the mid-Proterozoic deep ocean has evolved from fully oxygenated to globally euxinic (sulfidic) to a more heterogeneous, stratified water column with localized pockets of euxinia existing in predominantly iron-rich (ferruginous) deep waters. The Animikie Basin in the Lake Superior region has been essential in shaping our view of marine redox evolution over this time period. In this study, we present a multi-proxy paleoredox investigation of previously unanalyzed strata of the late Paleoproterozoic Animikie Basin using drill cores through the ~1.85?Ga Stambaugh Formation (Paint River Group) in the Iron River-Crystal Falls district of the Upper Peninsula of Michigan, USA. Based on previous tectonic reconstructions and analysis of sedimentary regimes, the Iron River-Crystal Falls section captures strata from among the deepest-water facies of the Animikie Basin. In contrast to previous work on sedimentary rocks in this basin, we find evidence from iron speciation, trace metal, and Mo isotope data for episodes of at least local deep-water oxygenation within a basin otherwise dominated by ferruginous and euxinic conditions. While trace-metal enrichments and iron speciation data suggest predominantly anoxic conditions, the occurrence of Mn-rich intervals (up to 12.3?wt% MnO) containing abundant Mn-Fe carbonate, and a wide range of Mo isotope data with extremely negative values (δ98/95Mo?=??1.0 to +1.1‰), record the shuttling of Mn-oxides from surface waters through oxic or suboxic waters to the sediment-water interface. We propose that such conditions are analogous to those of locally restricted modern and Holocene basins in the Baltic Sea, which receive episodic inflow of oxygenated water, producing similar geochemical signatures to those observed for the Animikie Basin. We argue that the mid-Proterozoic was characterized by a lack of a strong redox buffer (low sulfide, ferrous iron, and oxygen contents), and thus was vulnerable to dramatic, and at least local, redox shifts—including briefly oxygenated bottom waters. A refined view of the mid-Proterozoic ocean is emerging: one that was still predominantly anoxic, but marked by regional heterogeneities and short-term redox variability that may, in part, reflect a transitional state between prevailingly anoxic Archean and predominantly oxic Phanerozoic oceans.Poad, B.L.J., Maccarone, A.T., Yu, H., Mitchell, T.W., Saied, E.M., Arenz, C., Hornemann, T., Bull, J.N., Bieske, E.J., Blanksby, S.J., 2018. Differential-mobility spectrometry of 1-deoxysphingosine isomers: New insights into the gas phase structures of ionized lipids. Analytical Chemistry 90, 5343-5351. and structural identification of lipids remain a major challenge for contemporary lipidomics. Regioisomeric lipids differing only in position(s) of unsaturation are often not differentiated by conventional liquid chromatography–mass spectrometry approaches leading to the incomplete, or sometimes incorrect, assignation of molecular structure. Here we describe an investigation of the gas phase separations by differential-mobility spectrometry (DMS) of a series of synthetic analogues of the recently described 1-deoxysphingosine. The dependence of the DMS behavior on the position of the carbon–carbon double bond within the ionized lipid is systematically explored and compared to trends from complementary investigations, including collision cross-sections measured by drift tube ion mobility, reaction efficiency with ozone, and molecular dynamics simulations. Consistent trends across these modes of interrogation point to the importance of direct, through-space interactions between the charge site and the carbon–carbon double bond. Differences in the geometry and energetics of this intramolecular interaction underpin DMS separations and influence reactivity trends between regioisomers. Importantly, the disruption and reformation of these intramolecular solvation interactions during DMS are proposed to be the causative factor in the observed separations of ionized lipids which are shown to have otherwise identical collision cross-sections. These findings provide key insights into the strengths and limitations of current ion-mobility technologies for lipid isomer separations and can thus guide a more systematic approach to improved analytical separations in lipidomics.Ponce de León, M.S., Koesbardiati, T., Weissmann, J.D., Milella, M., Reyna-Blanco, C.S., Suwa, G., Kondo, O., Malaspinas, A.-S., White, T.D., Zollikofer, C.P.E., 2018. Human bony labyrinth is an indicator of population history and dispersal from Africa. Proceedings of the National Academy of Sciences 115, 4128-4133.: The cavity system of the inner ear—the so-called bony labyrinth—houses the senses of balance and hearing. This structure is embedded in dense petrous bone, fully formed by birth and generally well preserved in human skeletal remains, thus providing a rich source of morphological information about past populations. Here we show that labyrinthine morphology tracks genetic distances and geography in an isolation-by-distance model with dispersal from Africa. Because petrous bones have become prime targets of ancient DNA recovery, we propose that all destructive studies first acquire high-resolution 3D computed-tomography data prior to any invasive sampling. Such data will constitute an important archive of morphological variation in past and present populations, and will permit individual-based genotype–phenotype comparisons.Abstract: The dispersal of modern humans from Africa is now well documented with genetic data that track population history, as well as gene flow between populations. Phenetic skeletal data, such as cranial and pelvic morphologies, also exhibit a dispersal-from-Africa signal, which, however, tends to be blurred by the effects of local adaptation and in vivo phenotypic plasticity, and that is often deteriorated by postmortem damage to skeletal remains. These complexities raise the question of which skeletal structures most effectively track neutral population history. The cavity system of the inner ear (the so-called bony labyrinth) is a good candidate structure for such analyses. It is already fully formed by birth, which minimizes postnatal phenotypic plasticity, and it is generally well preserved in archaeological samples. Here we use morphometric data of the bony labyrinth to show that it is a surprisingly good marker of the global dispersal of modern humans from Africa. Labyrinthine morphology tracks genetic distances and geography in accordance with an isolation-by-distance model with dispersal from Africa. Our data further indicate that the neutral-like pattern of variation is compatible with stabilizing selection on labyrinth morphology. Given the increasingly important role of the petrous bone for ancient DNA recovery from archaeological specimens, we encourage researchers to acquire 3D morphological data of the inner ear structures before any invasive sampling. Such data will constitute an important archive of phenotypic variation in present and past populations, and will permit individual-based genotype–phenotype comparisons.Portilho-Ramos, R.C., Cruz, A.P.S., Barbosa, C.F., Rathburn, A.E., Mulitza, S., Venancio, I.M., Schwenk, T., Rühlemann, C., Vidal, L., Chiessi, C.M., Silveira, C.S., 2018. Methane release from the southern Brazilian margin during the last glacial. Scientific Reports 8, Article 5948. methane release can significantly affect the global carbon cycle and climate. Appreciable quantities of methane are stored in continental margin sediments as shallow gas and hydrate deposits, and changes in pressure, temperature and/or bottom-currents can liberate significant amounts of this greenhouse gas. Understanding the spatial and temporal dynamics of marine methane deposits and their relationships to environmental change are critical for assessing past and future carbon cycle and climate change. Here we present foraminiferal stable carbon isotope and sediment mineralogy records suggesting for the first time that seafloor methane release occurred along the southern Brazilian margin during the last glacial period (40–20?cal ka BP). Our results show that shallow gas deposits on the southern Brazilian margin responded to glacial?interglacial paleoceanographic changes releasing methane due to the synergy of sea level lowstand, warmer bottom waters and vigorous bottom currents during the last glacial period. High sea level during the Holocene resulted in an upslope shift of the Brazil Current, cooling the bottom waters and reducing bottom current strength, reducing methane emissions from the southern Brazilian margin.Potts, R., Behrensmeyer, A.K., Faith, J.T., Tryon, C.A., Brooks, A.S., Yellen, J.E., Deino, A.L., Kinyanjui, R., Clark, J.B., Haradon, C.M., Levin, N.E., Meijer, H.J.M., Veatch, E.G., Owen, R.B., Renaut, R.W., 2018. Environmental dynamics during the onset of the Middle Stone Age in eastern Africa. Science 360, 86-90.: Development of the African Middle Stone Age (MSA) before 300,000 years ago raises the question of how environmental change influenced the evolution of behaviors characteristic of early Homo sapiens. We used temporally well-constrained sedimentological and paleoenvironmental data to investigate environmental dynamics before and after the appearance of the early MSA in the Olorgesailie basin, Kenya. In contrast to the Acheulean archeological record in the same basin, MSA sites are associated with a markedly different faunal community, more pronounced erosion-deposition cycles, tectonic activity, and enhanced wet-dry variability. Aspects of Acheulean technology in this region imply that, as early as 615,000 years ago, greater stone material selectivity and wider resource procurement coincided with an increased pace of land-lake fluctuation, potentially anticipating the adaptability of MSA hominins.Editor's Summary: The Middle Stone Age in Africa. The Olorgesailie basin in the southern Kenya rift valley contains sediments dating back to 1.2 million years ago, preserving a long archaeological record of human activity and environmental conditions. Three papers present the oldest East African evidence of the Middle Stone Age (MSA) and elucidate the system of technology and behavior associated with the origin of Homo sapiens. Potts et al. present evidence for the demise of Acheulean technology that preceded the MSA and describe variations in late Acheulean hominin behavior that anticipate MSA characteristics. The transition to the MSA was accompanied by turnover of large mammals and large-scale landscape change. Brooks et al. establish that ～320,000 to 305,000 years ago, the populations in eastern Africa underwent a technological shift upon procurement of distantly sourced obsidian for toolmaking, indicating the early development of social exchange. Deino et al. provide the chronological underpinning for these discoveries.Prentice, B.M., Ryan, D.J., Van de Plas, R., Caprioli, R.M., Spraggins, J.M., 2018. Enhanced ion transmission efficiency up to m/z 24?000 for MALDI protein imaging mass spectrometry. Analytical Chemistry 90, 5090-5099. molecular identification of species of interest is an important part of an imaging mass spectrometry (IMS) experiment. The high resolution accurate mass capabilities of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) have recently been shown to facilitate the identification of proteins in matrix-assisted laser desorption/ionization (MALDI) IMS. However, these experiments are typically limited to proteins giving rise to ions of relatively low m/z due to difficulties transmitting and measuring large molecular weight ions of low charge states. Herein we have modified the source gas manifold of a commercial MALDI FT-ICR MS to regulate the gas flow and pressure to maximize the transmission of large m/z protein ions through the ion funnel region of the instrument. By minimizing the contribution of off-axis gas disruption to ion focusing and maximizing the effective potential wall confining the ions through pressure optimization, the signal-to-noise ratios (S/N) of most protein species were improved by roughly 1 order of magnitude compared to normal source conditions. These modifications enabled the detection of protein standards up to m/z 24?000 and the detection of proteins from tissue up to m/z 22?000 with good S/N, roughly doubling the mass range for which high quality protein ion images from rat brain and kidney tissue could be produced. Due to the long time-domain transients (>4 s) required to isotopically resolve high m/z proteins, we have used these data as part of an FT-ICR IMS-microscopy data-driven image fusion workflow to produce estimated protein images with both high mass and high spatial resolutions.Presentato, A., Cappelletti, M., Sansone, A., Ferreri, C., Piacenza, E., Demeter, M.A., Crognale, S., Petruccioli, M., Milazzo, G., Fedi, S., Steinbüchel, A., Turner, R.J., Zannoni, D., 2018. Aerobic growth of Rhodococcus aetherivorans BCP1 using selected naphthenic acids as the sole carbon and energy sources. Frontiers in Microbiology 9, 672. doi: 10.3389/fmicb.2018.00672. acids (NAs) are an important group of toxic organic compounds naturally occurring in hydrocarbon deposits. This work shows that Rhodococcus aetherivorans BCP1 cells not only utilize a mixture of eight different NAs (8XNAs) for growth but they are also capable of marked degradation of two model NAs, cyclohexanecarboxylic acid (CHCA) and cyclopentanecarboxylic acid (CPCA) when supplied at concentrations from 50 to 500 mgL-1. The growth curves of BCP1 on 8XNAs, CHCA, and CPCA showed an initial lag phase not present in growth on glucose, which presumably was related to the toxic effects of NAs on the cell membrane permeability. BCP1 cell adaptation responses that allowed survival on NAs included changes in cell morphology, production of intracellular bodies and changes in fatty acid composition. Transmission electron microscopy (TEM) analysis of BCP1 cells grown on CHCA or CPCA showed a slight reduction in the cell size, the production of EPS-like material and intracellular electron-transparent and electron-dense inclusion bodies. The electron-transparent inclusions increased in the amount and size in NA-grown BCP1 cells under nitrogen limiting conditions and contained storage lipids as suggested by cell staining with the lipophilic Nile Blue A dye. Lipidomic analyses revealed significant changes with increases of methyl-branched (MBFA) and polyunsaturated fatty acids (PUFA) examining the fatty acid composition of NAs-growing BCP1 cells. PUFA biosynthesis is not usual in bacteria and, together with MBFA, can influence structural and functional processes with resulting effects on cell vitality. Finally, through the use of RT (Reverse Transcription)-qPCR, a gene cluster (chcpca) was found to be transcriptionally induced during the growth on CHCA and CPCA. Based on the expression and bioinformatics results, the predicted products of the chcpca gene cluster are proposed to be involved in aerobic NA degradation in R. aetherivorans BCP1. This study provides first insights into the genetic and metabolic mechanisms allowing a Rhodococcus strain to aerobically degrade NAs.Purnell, M.A., Donoghue, P.J.C., Gabbott, S.E., McNamara, M.E., Murdock, D.J.E., Sansom, R.S., Smith, A., 2018. Experimental analysis of soft‐tissue fossilization: opening the black box. Palaeontology 61, 317-323. experiments provide important insights into fossils that preserve the remains of decay?prone soft tissues, tissues that are usually degraded and lost prior to fossilization. These fossils are among the most scientifically valuable evidence of ancient life on Earth, giving us a view into the past that is much less biased and incomplete than the picture provided by skeletal remains alone. Although the value of taphonomic experiments is beyond doubt, a lack of clarity regarding their purpose and limitations, and ambiguity in the use of terminology, are hampering progress. Here we distinguish between processes that promote information retention and those that promote information loss, in order to clarify the distinction between fossilization and preservation. Recognizing distinct processes of decay, mineralization and maturation, the sequence in which they act, and the potential for interactions, has important consequences for analysis of fossils, and for the design of taphonomic experiments. The purpose of well?designed taphonomic experiments is generally to understand decay, maturation and preservation individually, thus limiting the number of variables involved. Much work remains to be done, but these methodologically reductionist foundations will allow researchers to build towards more complex taphonomic experiments and a more holistic understanding and analysis of the interactions between decay, maturation and preservation in the fossilization of non?biomineralized remains. Our focus must remain on the key issue of understanding what exceptionally preserved fossils reveal about the history of biodiversity and evolution, rather than on debating the scope and value of an experimental approach.Qi, L., Xie, H., Gagné, J.-P., Chaillou, G., Massicotte, P., Yang, G.-P., 2018. Photoreactivities of two distinct dissolved organic matter pools in groundwater of a subarctic island. Marine Chemistry 202, 97-120. is a potentially significant source of dissolved organic matter (DOM) to coastal oceans where it is subject to photochemical transformation and thus possibly influences major marine biogeochemical processes. Furthermore, groundwater DOM usually receives little prior light exposure, making it suitable for probing the photoreactivity of source organic materials. In this study we collected two DOM pools in beach and inland groundwater of the ?les-de-la-Madeleine in the Gulf of St. Lawrence, characterized them with absorbance and fluorescence spectroscopy, and compared their photoreactivities. Beach groundwater (BGW) primarily comprised old, highly colored terrestrial DOM having high molecular weight (MW), strong humification, and low protein contents, whereas inland groundwater (IGW) largely contained fresh, less colored microbial-derived DOM with low molecular weight (MW), weaker humification, and higher protein contents. For both BGW and IGW, exposure to solar-simulated radiation led to increases in the E2/E3 quotient, biological index (BIX), and ammonium (NH4+) and decreases in absorbance, specific absorption coefficient at 254?nm (SUVα254), fluorescence index (FI), humification index (HIX), MW, and dissolved organic carbon (DOC). The irradiation also reduced the intensities of humic-like fluorescence peaks and PARAFAC-modeled humic components. On a fractional-absorption-loss basis, the photochemically induced fractional changes in BGW were comparable to those in IGB for SUVα254 and E2/E3, considerably larger for MW, BIX, and DOC, and substantially smaller for FI and HIX. On an absorbed-photon basis, the efficiencies of absorbance photobleaching and DOC photomineralization for DOM in BGW were 8.3 times and 2.0 times those of the respective photoprocesses for DOM in IGW, while the efficiency of photoammonification for DOM in BGW was 41% of that for DOM in IGW. Results from this study, in combination with those reported previously for surface waters, lead to a tentative paradigm: terrigenous DOM is more prone to absorbance photobleaching but less prone to photoammonification than microbial-derived DOM while the two DOM pools are comparably reactive with respect to DOC photomineralization.Ràfols, P., Vilalta, D., Brezmes, J., Ca?ellas, N., del Castillo, E., Yanes, O., Ramírez, N., Correig, X., 2018. Signal preprocessing, multivariate analysis and software tools for MA(LDI)‐TOF mass spectrometry imaging for biological applications. Mass Spectrometry Reviews 37, 281-306. spectrometry imaging (MSI) is a label?free analytical technique capable of molecularly characterizing biological samples, including tissues and cell lines. The constant development of analytical instrumentation and strategies over the previous decade makes MSI a key tool in clinical research. Nevertheless, most MSI studies are limited to targeted analysis or the mere visualization of a few molecular species (proteins, peptides, metabolites, or lipids) in a region of interest without fully exploiting the possibilities inherent in the MSI technique, such as tissue classification and segmentation or the identification of relevant biomarkers from an untargeted approach. MSI data processing is challenging due to several factors. The large volume of mass spectra involved in a MSI experiment makes choosing the correct computational strategies critical. Furthermore, pixel to pixel variation inherent in the technique makes choosing the correct preprocessing steps critical. The primary aim of this review was to provide an overview of the data?processing steps and tools that can be applied to an MSI experiment, from preprocessing the raw data to the more advanced strategies for image visualization and segmentation. This review is particularly aimed at researchers performing MSI experiments and who are interested in incorporating new data?processing features, improving their computational strategy, and/or desire access to data?processing tools currently available.Rahman, M.M., Chen, L.C., 2018. Analytical characteristics of nano-electrospray operated under super-atmospheric pressure. Analytica Chimica Acta 1021, 78-84. nanoelectrospray ionization (nanoESI) source is a recently developed technique in which the electrospray ionization is generated inside an enclosed chamber with gas pressure higher than the atmospheric pressure. In this paper, the performance of nanoESI under different gas pressures, emitter position, ion inlet temperature, additive for desalination are presented. Under a pressure of 2?bars, the nanoESI is almost eased from the electrical discharge problem, and that offers a wider tuning window for the emitter potential to produces a higher and more stable ion signal. With optimized ion inlet temperature, the high-pressure operation facilitates the generation of ion species of higher charge-state from the highly aqueous solution, and produced less sodium adducts. A preparation method for the high-throughput analysis of raw biological samples using disposable plastic nanoESI emitter is also described.Raina, J.-B., 2018. The life aquatic at the microscale. mSystems 3, DOI: 10.1128/mSystems.00150-17. are more than one million microbial cells in every drop of seawater, and their collective metabolisms not only recycle nutrients that can then be used by larger organisms but also catalyze key chemical transformations that maintain Earth’s habitability. Understanding how these microbes interact with each other and with multicellular hosts is critical to reliably quantify any functional aspect of their metabolisms and to predict their outcomes on larger scales. Following a large body of literature pioneered by Farooq Azam and colleagues more than 30?years ago, I emphasize the importance of studying microbial interactions at the appropriate scale if we want to fully decipher the roles that they play in oceanic ecosystems.Raji, W.O., Obadare, I.G., Odukoya, M.A., Johnson, L.M., 2018. Electrical resistivity mapping of oil spills in a coastal environment of Lagos, Nigeria. Arabian Journal of Geosciences 11, 144. years after the oil spillage and pipeline explosion that claimed about 100 human lives at Ijegun Community of Lagos–Nigeria, a combination of carefully designed 2D Electrical Resistivity Profilling and Vertical Electrical Sounding methods was deployed to map and characterise the subsurface around the contaminated site. Data acquired were processed, forward modelled and tomographically inverted to obtain the multi-dimensional resistivity distribution of subsurface. The results?of the study revealed high resistivity structures that indocate?the presence of contaminant (oil plumes) of different sizes and shapes around the oil leakage site. These high resistivity structures are absent in the tomograms and resistivity-depth slices computed for Iyana—a linear settlement not affected by oil spillage. The five geo-electric layers and the resistivities delineated in the area are the top soil layer, 220–670?Ωm; clayey sand layer, 300–1072?Ωm; top sand layer, 120–328?Ωm; mudstone/shale layer, 25–116?Ωm and the bottom sand layer, 15–69?Ωm. The base of the first four geo-electric layers corresponds to 3.9, 8.4, 27.2 and 34.6?m respectively. The two groundwater aquifers delineated correspond to the third and fifth geo-electric layers. The top aquifer has been infiltrated by oil plumes. The depth penetrated by the oil plume decreases from 32?m to about 24?m across the survey profiles from the two ends. It was concluded that the contaminant plumes from the oil spillage are yet to be completely degraded as at the time of the study. It is recommended that the contaminated site be remediated to remove or reduce the contaminant oil in the subsurface.Rakociński, M., Zatoń, M., Marynowski, L., Gedl, P., Lehmann, J., 2018. Redox conditions, productivity, and volcanic input during deposition of uppermost Jurassic and Lower Cretaceous organic-rich siltstones in Spitsbergen, Norway. Cretaceous Research 89, 126-147. this paper, uppermost Jurassic and Lower Cretaceous black organic-rich siltstones (Rurikfjellet Formation) from Carolinedalen (Isfjorden, Spitsbergen) are studied using integrated palynological, petrographic, and geochemical methods (organic and inorganic geochemistry as well as Rock-Eval pyrolysis) in order to decipher the depositional conditions prevailing during their sedimentation, the type of organic matter from which they were formed, and their potential for generating hydrocarbons. The age of these investigated sediments encompasses an interval from the upper Tithonian-Berriasian to the Hauterivian, dated on the basis of dinocyst biostratigraphy. The ammonoids found in loose form at the base of the investigated section, such as Laugeites groenlandicus, are indicative of the upper part of the middle Tithonian. Based on palynology, biomarkers, and Rock-Eval data, the kerogen in the investigated siltstones from Isfjorden is of the mixed II/III type; the organic matter is mixed marine and terrestrial in origin, and represents the early to peak ‘oil window’ maturation stage (Tmax around 440 °C).These siltstones were deposited under a high-productivity regime with oxic/dysoxic bottom water conditions, as evidenced from the size distribution of pyrite framboids, in which pyrites with diameters >5 μm predominate. Values of Th/U and Corg/P ratios generally above 3 and 30, respectively, along with pristane/phytane ratios >2 and sterane/hopane ratios <0.3, also indicate oxic to suboxic sedimentary conditions in the water column. Anoxia, if present, must have been short-lasting and formed oxygen minimum zone in the water column. Elevated productivity in the photic zone may have been generated by an increase in volcanic activity, as confirmed by higher Hg contents and/or terrigenous nutrient supply.Ramirez, R.M., Craddock, R.A., 2018. The geological and climatological case for a warmer and wetter early Mars. Nature Geoscience 11, 230-237. climate of early Mars remains a topic of intense debate. Ancient terrains preserve landscapes consistent with stream channels, lake basins and possibly even oceans, and thus the presence of liquid water flowing on the Martian surface 4 billion years ago. However, despite the geological evidence, determining how long climatic conditions supporting liquid water lasted remains uncertain. Climate models have struggled to generate sufficiently warm surface conditions given the faint young Sun—even assuming a denser early atmosphere. A warm climate could have potentially been sustained by supplementing atmospheric CO2 and H2O warming with either secondary greenhouse gases or clouds. Alternatively, the Martian climate could have been predominantly cold and icy, with transient warming episodes triggered by meteoritic impacts, volcanic eruptions, methane bursts or limit cycles. Here, we argue that a warm and semi-arid climate capable of producing rain is most consistent with the geological and climatological evidence.Ratzke, C., Denk, J., Gore, J., 2018. Ecological suicide in microbes. Nature Ecology & Evolution 2, 867-872. growth and survival of organisms often depend on interactions between them. In many cases, these interactions are positive and caused by a cooperative modification of the environment. Examples are the cooperative breakdown of complex nutrients in microbes or the construction of elaborate architectures in social insects, in which the individual profits from the collective actions of her peers. However, organisms can similarly display negative interactions by changing the environment in ways that are detrimental for them, for example by resource depletion or the production of toxic byproducts. Here we find an extreme type of negative interactions, in which Paenibacillus sp. bacteria modify the environmental pH to such a degree that it leads to a rapid extinction of the whole population, a phenomenon that we call ecological suicide. Modification of the pH is more pronounced at higher population densities, and thus ecological suicide is more likely to occur with increasing bacterial density. Correspondingly, promoting bacterial growth can drive populations extinct whereas inhibiting bacterial growth by the addition of harmful substances—such as antibiotics—can rescue them. Moreover, ecological suicide can cause oscillatory dynamics, even in single-species populations. We found ecological suicide in a wide variety of microbes, suggesting that it could have an important role in microbial ecology and evolution.Raza, N., Hashemi, B., Kim, K.-H., Lee, S.-H., Deep, A., 2018. Aromatic hydrocarbons in air, water, and soil: Sampling and pretreatment techniques. TrAC Trends in Analytical Chemistry 103, 56-73. co-occurrence of various aromatic hydrocarbon compounds (AHs) in all major environmental compartments (e.g., air, water, and soil) and the escalating risks they present to humans and animals highlight the significance of understanding the cycling of these compounds in and across systems. To precisely monitor the behavior of AHs and routes of their exposure, it is critical to obtain accurate measurements of these compounds. Therefore, sampling, pre-concentration, and detection methods should be optimized by each or through combination for each medium under proper QA procedures. In this work, we reviewed the sampling and pre-concentration procedures for AHs present in air, water, and soil media. This review will provide basic methodological knowledge needed for the accurate quantitation of AHs samples in air, water, and soil.Reich, P.B., Hobbie, S.E., Lee, T.D., Pastore, M.A., 2018. Unexpected reversal of C3 versus C4 grass response to elevated CO2 during a 20-year field experiment. Science 360, 317-320.: Theory predicts and evidence shows that plant species that use the C4 photosynthetic pathway (C4 species) are less responsive to elevated carbon dioxide (eCO2) than species that use only the C3 pathway (C3 species). We document a reversal from this expected C3-C4 contrast. Over the first 12 years of a 20-year free-air CO2 enrichment experiment with 88 C3 or C4 grassland plots, we found that biomass was markedly enhanced at eCO2 relative to ambient CO2 in C3 but not C4 plots, as expected. During the subsequent 8 years, the pattern reversed: Biomass was markedly enhanced at eCO2 relative to ambient CO2 in C4 but not C3 plots. Soil net nitrogen mineralization rates, an index of soil nitrogen supply, exhibited a similar shift: eCO2 first enhanced but later depressed rates in C3 plots, with the opposite true in C4 plots, partially explaining the reversal of the eCO2 biomass response. These findings challenge the current C3-C4 eCO2 paradigm and show that even the best-supported short-term drivers of plant response to global change might not predict long-term results.Editor's Summary: A short-term trend reversed. Theory and empirical data both support the paradigm that C4 plant species (in which the first product of carbon fixation is a four-carbon molecule) benefit less from rising carbon dioxide (CO2) concentrations than C3 species (in which the first product is a three-carbon molecule). This is because their different photosynthetic physiologies respond differently to atmospheric CO2 concentrations. Reich et al. document a reversal of this pattern in a 20-year CO2 enrichment experiment using grassland plots with each type of plant (see the Perspective by Hovenden and Newton). Over the first 12 years, biomass increased with elevated CO2 in C3 plots but not C4 plots, as expected. But over the next 8 years, the pattern reversed: Biomass increased in C4 plots but not C3 plots. Thus, even the best-supported short-term drivers of plant response to global change might not predict long-term results.Reinhardt, M., Duda, J.P., Blumenberg, M., Ostertag‐Henning, C., Reitner, J., Heim, C., Thiel, V., 2018. The taphonomic fate of isorenieratene in Lower Jurassic shales—controlled by iron? Geobiology 16, 237-251. derivatives of isorenieratene, an accessory pigment in brown‐colored green sulfur bacteria, are often used as tracers for photic zone anoxia through Earth's history, but their diagenetic behavior is still incompletely understood. Here, we assess the preservation of isorenieratene derivatives in organic‐rich shales (1.5–8.4 wt.% TOC) from two Lower Jurassic anoxic systems (B?chental oil shale, Tyrol, Austria; Posidonia Shale, Baden‐Württemberg, Germany). Bitumens and kerogens were investigated using catalytic hydropyrolysis (HyPy), closed‐system hydrous pyrolysis (in gold capsules), gas chromatography–mass spectrometry (GC–MS) and gas chromatography combustion isotope ratio‐mass spectrometry (GC‐C‐IRMS). Petrography and biomarkers indicate a syngenetic relationship between bitumens and kerogens. All bitumens contain abundant isorenieratane, diverse complex aromatized isorenieratene derivatives, and a pseudohomologous series of 2,3,6‐trimethyl aryl isoprenoids. In contrast, HyPy and mild closed‐system hydrous pyrolysis of the kerogens yielded only minor amounts of these compounds. Given the overall low maturity of the organic matter (below oil window), it appears that isorenieratene and its abundant derivatives from the bitumen had not been incorporated into the kerogens. Accordingly, sulfur cross‐linking, the key mechanism for sequestration of functionalized lipids into kerogens in anoxic systems, was not effective in the Jurassic environments studied. We explain this by (i) early cyclization/aromatization and (ii) hydrogenation reactions that have prevented effective sulfurization. In addition, (iii) sulfide was locally removed via anoxygenic photosynthesis and efficiently trapped by the reaction with sedimentary iron, as further indicated by elevated iron contents (4.0–8.7 wt.%) and the presence of abundant pyrite aggregates in the rock matrix. Although the combined processes have hampered the kerogen incorporation of isorenieratene and its derivatives, they may have promoted the long‐term preservation of these biomarkers in the bitumen fraction via early defunctionalization. This particular taphonomy of aromatic carotenoids has to be considered in studies of anoxic iron‐rich environments (e.g., the Proterozoic ocean). Ren, B., Hu, Y., Chen, B., Zhang, Y., Thiele, J., Shi, R., Liu, M., Bu, R., 2018. Soil pH and plant diversity shape soil bacterial community structure in the active layer across the latitudinal gradients in continuous permafrost region of northeastern China. Scientific Reports 8, Article 5619. the permafrost region of northeastern China, vegetation and soil environment have showed response to permafrost degradation triggered by global warming, but the corresponding variation of the soil microbial communities remains poorly investigated. Here, a field investigation in the continuous permafrost region was conducted to collect 63 soil samples from 21 sites along a latitudinal gradient to assess the distribution pattern of microbial communities and their correlation with environmental factors. High-throughput Illumina sequencing revealed that bacterial communities were dominated by Proteobacteria, Acidobacteria, Bacteroidetes and Actinobacteria. Both microbial richness and phylogenetic diversity decreased initially and then increased as the latitude increased. UniFrac analysis of microbial communities detected significant differences among latitudes. Variation partitioning analysis and structural equation models revealed that environmental variables, including geographic factors, plant-community factors and soil physicochemical factors, all played non-negligible roles in affecting the microbial community structures directly or indirectly. Redundancy analysis and boosted regression tree analysis further highlighted the influences of soil pH and plant richness on microbial community compositions and diversity patterns. Taken together, these results suggest that the distribution pattern of soil microbial communities shows distinct changes along the latitudinal gradients in northeastern China and is predominantly mediated by soil pH and plant diversity.Rey, K., Day, M.O., Amiot, R., Goedert, J., Lécuyer, C., Sealy, J., Rubidge, B.S., 2018. Stable isotope record implicates aridification without warming during the late Capitanian mass extinction. Gondwana Research 59, 1-8. late Capitanian mass extinction (~260 million years ago) represents one of the greatest biotic perturbations of the Phanerozoic and was the earliest mass extinction to affect terrestrial tetrapods and ecosystems. In the past, this extinction has been largely associated with taxonomic loss and ecological restructuring in marine environments but more recently it has also been recognised in terrestrial ecosystems. Though various environmental mechanisms have been proposed for the former, little evidence has yet been presented for the cause of terrestrial extinctions. We determined the stable oxygen and carbon isotope compositions of dentine apatite from twenty-eight specimens of the dicynodont therapsid Diictodon feliceps, to investigate the potential role of climate in driving terrestrial tetrapod extinctions. Studied specimens were recovered from a 270 m stratigraphic interval constraining the peak in tetrapod extinction rates in the uppermost Abrahamskraal Formation in the well-sampled main Karoo Basin of South Africa. Our results demonstrate a positive excursion of δ13C values coinciding with the extinction peak that is followed by a return to pre-extinction δ13C values, suggesting a local increase in aridity at the time of the extinction. For the same time interval, the δ18O values did not demonstrate statistically significant changes, suggesting constant temperature in the South African paleoenvironment. This unusual increase in aridity but not in temperature has been interpreted as the possible result of orogenesis in the Cape Fold Mountain source along the southern margin of Gondwana.Rezaei Dehshibi, R., Mohebbi, A., Riazi, M., Niakousari, M., 2018. Experimental investigation on the effect of ultrasonic waves on reducing asphaltene deposition and improving oil recovery under temperature control. Ultrasonics Sonochemistry 45, 204-212. well-known complication in the oil reservoir during oil production is asphaltene deposition in and around the production wellbore. Deposition of asphaltene around the production wellbore may cause a significant pressure drop and in turn loss of efficiency in the production process. Various mechanical and chemical methods have been employed in order to reduce asphaltene formation or to eliminate the precipitate. A novel technique which presented a great potential for prevention or elimination of asphaltene is spreading out the high energy ultrasound wave within the oil reservoir. In this study, in a glass micro-model, asphaltene precipitation was first simulated in a transparent porous medium and its removal by application of high energy ultrasound wave was then investigated. To simulate asphaltene precipitation, the micro-model was first saturated with oil and then a normal-pentane was injected. This was followed by flooding the porous media with brine while propagating ultrasound waves (30?kHz and 100?W) to eliminate asphaltene precipitation. The experiment setup was equipped with a temperature controller. The results indicate a significant reduction in asphaltene precipitation in the oil reservoir may be achieved by application of ultrasound energy. Asphaltene particle deposition has been solved reversibly in the oil layer of porous medium and with the oil layering mechanism, the rate of oil production has been increased. In some spots, water/oil emulsion has been formed because of the ultrasonic vibration on the wall. Both the crude and synthetic oils were examined.Richey, J.D., Upchurch, G.R., Monta?ez, I.P., Lomax, B.H., Suarez, M.B., Crout, N.M.J., Joeckel, R.M., Ludvigson, G.A., Smith, J.J., 2018. Changes in CO2 during Ocean Anoxic Event 1d indicate similarities to other carbon cycle perturbations. Earth and Planetary Science Letters 491, 172-182. greenhouse intervals of the Mesozoic were repeatedly punctuated by Ocean Anoxic Events (OAEs), major perturbations to the global carbon cycle and abrupt climate changes that may serve as relevant analogs for Earth's greenhouse gas-forced climate future. The key to better understanding these transient climate disruptions and possible CO2-forced tipping-points resides in high-resolution, precise, and accurate estimates of atmospheric CO2 for individual OAEs. Here we present a high-temporal resolution, multi-proxy pCO2 reconstruction for the onset of mid-Cretaceous (Albian–Cenomanian Boundary) OAE1d. Coupling of pCO2 estimates with carbon isotopic compositions (δ13δ13C) of charcoal, vitrain, and cuticle from the Rose Creek Pit (RCP), Nebraska, reveals complex phasing, including a lag between the well-documented negative δ13δ13C excursion defining the onset of OAE1d and the CO2 increase. This lag indicates that increased CO2 or other C-based greenhouse gases may not have been the primary cause of the negative excursion. Our study reveals a pCO2 increase within the interval of the negative δ13δ13C excursion, reaching a maximum of up to ～840 ppm (95% confidence interval ?307 ppm/+167 ppm) toward its end. The reconstructed magnitude of CO2 increase (～357 ppm) is similar to that of Late Cretaceous OAE2 but of smaller magnitude than that of other major carbon cycle perturbations of the Mesozoic assessed via stomatal methods (e.g., the Toarcian OAE [TOAE], Triassic–Jurassic boundary event, Cretaceous–Paleogene Boundary event). Furthermore, our results indicate a possible shared causal or developmental mechanism with OAE1a and the TOAE.Riekenberg, P.M., Carney, R.S., Fry, B., 2018. Shell carbon isotope indicators of metabolic activity in the deep-sea mussel Bathymodiolus childressi. Deep Sea Research Part I: Oceanographic Research Papers 134, 48-54. incorporation of metabolic carbon (Cm) into shells of mollusks has been used as an indicator of animal condition and availability of food resources in estuarine and freshwater settings. This study examines Cm in Bathymodiolus childressi, a marine cold seep mussel dependent on methanotrophic symbionts. As seeps develop, mature, and go quiescent, methane supply will vary and affect the amount of metabolic carbon deposited into the growing shell. B. childressi (n=136) were live-collected from two seep sites over a 17 year period in the Northern Gulf of Mexico to investigate whether changes in Cm were detectable between sites and across years. Significant differences in Cm were observed between mussel populations at Brine Pool (15.4±0.4%) and Bush Hill (10.3±0.3%). Cm also changed significantly within each site across year (Bush Hill 1991: 12.2±0.5%, 1992: 17.3±0.8%) and decadal time scales (Brine Pool 1989: 15.5±0.7%, 2006: 19.5±0.7%). These findings agree with previous studies that found mussel condition was higher at Brine Pool and correlate well with a trophic mixing model that indicated significantly higher methane source utilization at the Brine Pool (65±1.1%) than at Bush Hill (49±1.6%). Further development of this method should allow for assessment of Cm in shell assemblages as an indicator of historical resource availability at both active and former cold seep sites.Roberts, L.R., Holmes, J.A., Leng, M.J., Sloane, H.J., Horne, D.J., 2018. Effects of cleaning methods upon preservation of stable isotopes and trace elements in shells of Cyprideis torosa (Crustacea, Ostracoda): Implications for palaeoenvironmental reconstruction. Quaternary Science Reviews 189, 197-209. trace element (Sr/Ca and Mg/Ca) and stable isotope (δ18O and δ13C) geochemistry of fossil ostracod valves provide valuable information, particularly in lacustrine settings, on palaeo-water composition and palaeotemperature. The removal of sedimentary and organic contamination prior to geochemical analysis is essential to avoid bias of the results. Previous stable isotope and trace element work on ostracod shells has, however, employed different treatments for the removal of contamination beyond simple ‘manual’ cleaning using a paint brush and methanol under a low-power binocular microscope. For isotopic work pre-treatments include chemical oxidation, vacuum roasting and plasma ashing, and for trace element work sonication, chemical oxidation and reductive cleaning. The impact of different treatments on the geochemical composition of the valve calcite has not been evaluated in full, and a universal protocol has not been established. Here, a systematic investigation of the cleaning methods is undertaken using specimens of the ubiquitous euryhaline species, Cyprideis torosa. Cleaning methods are evaluated by undertaking paired analyses on a single carapace (comprising two valves); in modern ostracods, whose valves are assumed to be unaltered, the two valves should have identical geochemical and isotopic composition. Hence, when one valve is subjected to the chosen treatment and the other to simple manual cleaning any difference in composition can confidently be assigned to the treatment method. We show that certain cleaning methods have the potential to cause alteration to the geochemical signal, particularly Mg/Ca and δ18O, and hence have implications for palaeoenvironmental reconstructions. For trace–element determinations we recommend cleaning by sonication and for stable isotope analysis, oxidation by hydrogen peroxide. These methods remove contamination, yet do not significantly alter the geochemical signal.Rochman, F.F., Kim, J.-J., Rijpstra, W.I.C., Sinninghe Damsté, J.S., Schumann, P., Verbeke, T.J., Dunfield, P.F., 2018. Oleiharenicola alkalitolerans gen. nov., sp. nov., a new member of the phylum Verrucomicrobia isolated from an oilsands tailings pond. International Journal of Systematic and Evolutionary Microbiology 68, 1078-1084. novel member of the phylum Verrucomicrobia was isolated from an oilsands tailings pond in Alberta, Canada. Cells of isolate NVTT are Gram-negative, strictly aerobic, non-pigmented, non-motile cocci to diplococci 0.5–1.0??m in diameter. The bacterium is neutrophilic (optimum pH 6.0–8.0) but alkalitolerant, capable of growth between pH 5.5 and 11.0. The temperature range for growth is 15–40?°C (optimum 25–37?°C). Carbon and energy sources include sugars and organic acids. Nitrogen sources include nitrate, urea, l-glycine, l-alanine, l-proline and l-serine. Does not fix atmospheric nitrogen. Does not require NaCl and is inhibited at NaCl concentrations above 3.0?% (w/v). The DNA G+C?content of strain NVTT, based on a draft genome sequence, is 66.1?mol%. MK-6 and MK-7 are the major respiratory quinones. Major cellular fatty acids are anteiso-C15?:?0 and iso-C15?:?0. Phylogenetic analysis of 16S rRNA gene sequences revealed that the strain belongs to the family Opitutaceae of the phylum Verrucomicrobia. The most closely related validated species is Opitutus terrae (93.7?% 16S rRNA gene sequence identity to its type strain PB90-1T). Based on genotypic, phenotypic and chemotaxonomic characteristics, it was concluded that this strain represents a novel genus and species, for which the name Oleiharenicola alkalitolerans gen. nov., sp. nov. is proposed. The type strain of this novel species is NVTT (=ATCC BAA-2697T;=DSM 29249T). The IMG/JGI genome submission ID of Oleiharenicola alkalitolerans NVTT is 43214. The GOLD Analysis Project ID for the genome is Ga0049946.Romera-Castillo, C., Pinto, M., Langer, T.M., ?lvarez-Salgado, X.A., Herndl, G.J., 2018. Dissolved organic carbon leaching from plastics stimulates microbial activity in the ocean. Nature Communications 9, Article 1430. 5.25 trillion plastic pieces are floating at the sea surface. The impact of plastic pollution on the lowest trophic levels of the food web, however, remains unknown. Here we show that plastics release dissolved organic carbon (DOC) into the ambient seawater stimulating the activity of heterotrophic microbes. Our estimates indicate that globally up to 23,600 metric tons of DOC are leaching from marine plastics annually. About 60% of it is available to microbial utilization in less than 5 days. If exposed to solar radiation, however, this DOC becomes less labile. Thus, plastic pollution of marine surface waters likely alters the composition and activity of the base of the marine food webs. It is predicted that plastic waste entering the ocean will increase by a factor of ten within the next decade, resulting in an increase in plastic-derived DOC that might have unaccounted consequences for marine microbes and for the ocean system.Romero, C.M., Engel, R.E., D'Andrilli, J., Chen, C., Zabinski, C., Miller, P.R., Wallander, R., 2018. Patterns of change in permanganate oxidizable soil organic matter from semiarid drylands reflected by absorbance spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry. Organic Geochemistry 120, 19-30. matter (OM) oxidized by slightly alkaline KMnO4, termed permanganate-oxidizable carbon (POXC), has recently emerged as a standardized indicator of active, labile carbon within soil quality frameworks. Yet, qualitative information on POXC, particularly in semiarid drylands, is very scarce. The aim of this study was to characterize POXC within three long-term field experiments in Montana, USA: (i) across a wide range of edaphic (e.g.,% clay) and management conditions (e.g., cropping intensity) (n = 148); and (ii) to identify the molecular composition of soil OM before and after KMnO4 treatment using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). The content of POXC was significantly greater under perennial (382–685 mg/kg) or annual cropping (404–607 mg/kg) than fallow-wheat (359–543 mg/kg) systems. Soil OM changes, however, were equally or better expressed when considering soil organic carbon (SOC) concentration. The occurrence of POXC paralleled SOC (R = 0.87; P <0.001) and total nitrogen (TN) (R = 0.82; P <0.001) concentration, regardless of soil textural differences. The ESI FT-ICR MS analyses of aqueous soil extracts indicated that the KMnO4 reaction oxidized dissolved OM of diverse molecular character. OM molecular composition after KMnO4 treatment was enriched by strongly reduced chemical constituents (O/C <0.4) at greater condensed aromaticity (AI >0.67) and hydrogen saturation (aliphatic composition; H/C >1.5) across all heterogeneous groups (CcHhNnOoSs). Although POXC is a rapid assay widely used for characterizing soil OM dynamics, it may not provide a clear advantage over SOC concentration in semiarid drylands. The view of POXC as a merely labile, simple biodegradable OM fraction needs to be reconsidered.Rontani, J.F., Aubert, C., Belt, S.T., 2018. Electron ionization mass spectrometry fragmentation and multiple reaction monitoring quantification of bacterial metabolites of the sea ice biomarker proxy IP25 in Arctic sediments. Rapid Communications in Mass Spectrometry 32, 775-783.: 3,9,13‐Trimethyl‐6‐(1,5‐dimethylhexyl)tetradecan‐1,2‐diol and 2,8,12‐trimethyl‐5‐(1,5‐dimethylhexyl)tridecanoic acid appear to be produced during the bacterial metabolism of IP25, a highly branched isoprenoid lipid often employed for past Arctic sea ice reconstruction. Characterization and quantification of these metabolites in sediments are essential to determine if bacterial degradation may exert a significant influence on IP25‐based palaeo sea ice reconstructions. Methods: Electron ionization mass spectrometry (EIMS) fragmentation pathways of 3,9,13‐trimethyl‐6‐(1,5‐dimethylhexyl)tetradecan‐1,2‐diol and 2,8,12‐trimethyl‐5‐(1,5‐dimethylhexyl)tridecanoic acid trimethylsilyl (TMS) derivatives were investigated. These pathways were deduced by: (i) low‐energy collision‐induced dissociation (CID) gas chromatography/tandem mass spectrometry (GC/MS/MS), (ii) accurate mass measurement, and (iii) deuterium labelling. Results: CID‐MS/MS analyses, accurate mass measurement and deuterium‐labelling experiments enabled us to elucidate the EIMS fragmentations of 3,9,13‐trimethyl‐6‐(1,5‐dimethylhexyl)tetradecan‐1,2‐diol and 2,8,12‐trimethyl‐5‐(1,5‐dimethylhexyl)tridecanoic acid TMS derivatives. Some specific fragment ions useful in addition to chromatographic retention times for further characterization could be identified. As an application of some of the described fragmentations, the TMS derivatives of these metabolites were characterized and quantified in MRM mode in different Arctic sediments. Conclusions: EIMS fragmentations of 3,9,13‐trimethyl‐6‐(1,5‐dimethylhexyl)tetradecan‐1,2‐diol and 2,8,12‐trimethyl‐5‐(1,5‐dimethylhexyl)tridecanoic acid TMS derivatives exhibit specific fragment ions, which appear to be very useful for the quantification of these bacterial metabolites of the palaeo tracer IP25 in sediments. Rossabi, S., Helmig, D., 2018. Changes in atmospheric butanes and pentanes and their isomeric ratios in the continental United States. Journal of Geophysical Research: Atmospheres 123, 3772-3790. hydrocarbons have been used as tracers in research on emissions and atmospheric oxidation chemistry. This research investigates source region mixing ratio trends of the nonmethane hydrocarbons i‐butane, n‐butane, i‐pentane, and n‐pentane, and the (i/n) isomeric ratios of these compounds between 2001 and 2015. Data collected at Photochemical Assessment Monitoring Stations, mandated by the U.S. Environmental Protection Agency in ozone nonattainment areas, and data collected at Global Greenhouse Gas Reference Network sites within the National Oceanic and Atmospheric Administration network, and analyzed at the Institute of Arctic and Alpine Research at the University of Colorado‐Boulder, were examined. Among all considered species, linear regression analyses on concentration time series had negative slopes at 81% of sites, indicating predominantly declining butane and pentane atmospheric concentrations. Mostly negative slopes (78% of sites) were found for the (i/n) butane and pentane isomeric ratios, including all six and seven statistically significant (i/n) butane and pentane trends, respectively. Over the ~15 year investigation period and averaged over all sites, total relative changes were ~30 and 45% for the (i/n) ratios of butanes and pentanes, respectively, with a relative increase in the prominence of the n‐isomers. Most likely causes include changing isomeric ratios in gasoline sector emissions, and increasing influence of oil and natural gas industry emissions. Changes in concentrations and isomeric ratios depend on proximity of contributing emission sources to measurement sites.Rouillard, J., García‐Ruiz, J.M., Gong, J., Zuilen, M.A., 2018. A morphogram for silica‐witherite biomorphs and its application to microfossil identification in the early earth rock record. Geobiology 16, 279-296. hydrothermal environments formed a likely site for the origin and early evolution of life. These are also the settings, however, were complex abiologic structures can form. Low‐temperature serpentinization of ultramafic crust can generate alkaline, silica‐saturated fluids in which carbonate–silica crystalline aggregates with life‐like morphologies can self‐assemble. These “biomorphs” could have adsorbed hydrocarbons from Fischer–Tropsch type synthesis processes, leading to metamorphosed structures that resemble carbonaceous microfossils. Although this abiogenic process has been extensively cited in the literature and has generated important controversy, so far only one specific biomorph type with a filamentous shape has been discussed for the interpretation of Archean microfossils. It is therefore critical to precisely determine the full distribution in morphology and size of these biomorphs, and to study the range of plausible geochemical conditions under which these microstructures can form. Here, a set of witherite‐silica biomorph synthesis experiments in silica‐saturated solutions is presented, for a range of pH values (from 9 to 11.5) and barium ion concentrations (from 0.6 to 40 mmol/L BaCl2). Under these varying conditions, a wide range of life‐like structures is found, from fractal dendrites to complex shapes with continuous curvature. The size, spatial concentration, and morphology of the biomorphs are strongly controlled by environmental parameters, among which pH is the most important. This potentially limits the diversity of environments in which the growth of biomorphs could have occurred on Early Earth. Given the variety of the observed biomorph morphologies, our results show that the morphology of an individual microstructure is a poor criterion for biogenicity. However, biomorphs may be distinguished from actual populations of cellular microfossils by their wide, unimodal size distribution. Biomorphs grown by diffusion in silica gel can be differentiated by their continuous gradient in size, spatial density, and morphology along the direction of diffusion.Rowe, O.F., Dinasquet, J., Paczkowska, J., Figueroa, D., Riemann, L., Andersson, A., 2018. Major differences in dissolved organic matter characteristics and bacterial processing over an extensive brackish water gradient, the Baltic Sea. Marine Chemistry 202, 27-36. organic matter (DOM) in marine waters is a complex mixture of compounds and elements that contribute substantially to the global carbon cycle. The large reservoir of dissolved organic carbon (DOC) represents a vital resource for heterotrophic bacteria. Bacteria can utilise, produce, recycle and transform components of the DOM pool, and the physicochemical characteristics of this pool can directly influence bacterial activity; with consequences for nutrient cycling and primary productivity. In the present study we explored bacterial transformation of naturally occurring DOM across an extensive brackish water gradient in the Baltic Sea. Highest DOC utilisation (indicated by decreased DOC concentration) was recorded in the more saline southerly region where waters are characterised by more autochthonous DOM. These sites expressed the lowest bacterial growth efficiency (BGE), whereas in northerly regions, characterised by higher terrestrial and allochthonous DOM, the DOC utilisation was low and BGE was highest. Bacterial processing of the DOM pool in the south resulted in larger molecular weight compounds and compounds associated with secondary terrestrial humic matter being degraded, and a processed DOM pool that was more aromatic in nature and contributed more strongly to water colour; while the opposite was true in the north. Nutrient concentration and stoichiometry and DOM characteristics affected bacterial activity, including metabolic status (BGE), which influenced DOM transformations. Our study highlights dramatic differences in DOM characteristics and microbial carbon cycling in sub-basins of the Baltic Sea. These findings are critical for our understanding of carbon and nutrient biogeochemistry, particularly in light of climate change scenarios.Ruebsam, W., Müller, T., Kovács, J., Pálfy, J., Schwark, L., 2018. Environmental response to the early Toarcian carbon cycle and climate perturbations in the northeastern part of the West Tethys shelf. Gondwana Research 59, 144-158. Toarcian (Early Jurassic; ~183?Ma) climate and carbon cycle perturbations were accompanied by widespread accumulation of bituminous sediments, formed during the Toarcian Oceanic Anoxic Event (T-OAE). On the northwestern Tethyan shelf, organic carbon accumulation was particularly widespread in hydrodynamically restricted regions of the European Epicontinental Basin System (EEBS) where it peaked during the formation of euxinic waters extending into the photic zone. In the adjacent northeastern West Tethys shelf (NE-WTS), an area proximal to the deeper and better ventilated NW Tethys, deposition of strata enriched in organic matter was restricted to depressions of limited spatial extent. While numerous works have addressed the bituminous strata from the EEBS, evolution of environmental conditions and drivers of organic matter accumulation in areas proximal to the open Tethys have received much less attention. Here, we investigated a stratigraphically well-constrained, exceptionally organic matter-rich sediment succession from the NE-WTS deposited during the T-OAE. Organic and isotope geochemical investigations provided insights into the evolution and dynamics of environmental conditions during the T-OAE in a setting proximal to the Tethys. The sedimentary rocks sampled for this study originated from a surface outcrop that experienced weathering-related alteration of its mineral constituents. In particular, sulfides (mainly pyrite) were significantly altered, resulting in a near-quantitative loss of sulfur. In contrast, kerogen as well as bitumen fractions have not been significantly affected by weathering processes and carry a robust paleoenvironmental signal. The new data show that organic carbon accumulation occurred as a direct response to changing environmental conditions that also led to the early Toarcian carbon cycle perturbation. Increase in organic carbon burial occurred in a stepwise manner, following multiple injections of 12C-enriched carbon into the Earth's ocean-atmosphere system. High algal productivity and the subsequent organic matter decomposition by sulfate reducing bacteria led to an expansion of H2S-rich waters into the photic zone, which promoted the growth of Chlorobiaceae. A steady increase in nitrogen isotope values testified to intensified denitrification in an expanded oxygen minimum zone. The resulting decline in the availability of bio-utilizable nitrogen in combination with harsh environmental conditions promoted the proliferation of cyanobacteria as indicated by increasing abundances of 2α?methyl?hopanes. Formation of euxinic waters in the NE-WTS was not associated with a freshwater driven salinity stratification. Organic geochemical salinity indicators (methylated chromanes) attest to normal marine salinity, supporting a strong influence of Tethyan water masses. This study enhances our knowledge on the environmental response towards the early Toarcian climate and carbon cycle perturbations in a setting proximal to the Tethys. We demonstrate that photic zone euxinia was a common and particularly widespread feature of the T-OAE and has not been confined to the hydrodynamically restricted EEBS.Rummel, J.D., Kminek, G., 2018. It's time to develop a new “draft test protocol” for a Mars sample return mission (or two…). Astrobiology 18, 377-380. The last time NASA envisioned a sample return mission from Mars, the development of a protocol to support the analysis of the samples in a containment facility resulted in a “Draft Test Protocol” that outlined required preparations “for the safe receiving, handling, testing, distributing, and archiving of martian materials here on Earth” (Rummel et al., 2002). This document comprised a specific protocol to be used to conduct a biohazard test for a returned martian sample, following the recommendations of the Space Studies Board of the US National Academy of Sciences. Given the planned launch of a sample-collecting and sample-caching rover (Mars 2020) in 2 years' time, and with a sample return planned for the end of the next decade, it is time to revisit the Draft Test Protocol to develop a sample analysis and biohazard test plan to meet the needs of these future missions.Russell, S.S., 2018. The formation of the solar system: A recipe for worlds. Elements 14, 113-118. paper summarises the recipe – the raw and processed ingredients plus some of the processes – behind making our solar system 4,600 million years ago. Like a gourmand recipe, the solar system formed from many disparate ingredients, many of these ingredients themselves being the products of complex processes. Thus, to create the habitable solar system we see today required extensive work and processing. However, unlike a food recipe, much of how this happened is poorly understood, although a combination of new observations and analysis is ensuring that progress continues to be made.Sakai, H.D., Kurosawa, N., 2018. Saccharolobus caldissimus gen. nov., sp. nov., a facultatively anaerobic iron-reducing hyperthermophilic archaeon isolated from an acidic terrestrial hot spring, and reclassification of Sulfolobus solfataricus as Saccharolobus solfataricus comb. nov. and Sulfolobus shibatae as Saccharolobus shibatae comb. nov. International Journal of Systematic and Evolutionary Microbiology 68, 1271-1278. novel hyperthermophilic archaeon of strain HS-3T, belonging to the family Sulfolobaceae , was isolated from an acidic terrestrial hot spring in Hakone Ohwaku-dani, Japan. Based on 16S rRNA gene sequence analysis, the closest phylogenetic relatives of strain HS-3T were, first, Sulfolobus solfataricus (96.4?%) and, second, Sulfolobus shibatae (96.2?%), indicating that the strain belongs to the genus Sulfolobus . However, the sequence similarity to the type species of the genus Sulfolobus (Sulfolobus acidocaldarius) was remarkably low (91.8?%). In order to determine whether strain HS-3T belongs to the genus Sulfolobus , its morphological, biochemical and physiological characteristics were examined in parallel with those of S. solfataricus and S. shibatae. Although there were some differences in chemolithotrophic growth between strain HS-3T, S. solfataricus and S. shibatae, their temperature, pH and facultatively anaerobic characteristics of growth, and their utilization of various sugars were almost identical. In contrast, the utilization of various sugars by S. acidocaldarius was quite different from that of HS-3T, S. solfataricus and S. shibatae. Phylogenetic evidence based on the 16S and the 23S rRNA gene sequences also clearly distinguished the monophyletic clade composed of strain HS-3T, S. solfataricus and S. shibatae from S. acidocaldarius. Based on these results, we propose a new genus and species, Saccharolobus caldissimus gen. nov., sp. nov., for strain HS-3T, as well as two reclassifications, Saccharolobus solfataricus comb. nov. and Saccharolobus shibatae comb. nov. The type strain of Saccharolobus caldissimus is HS-3T (=JCM 32116T and InaCC Ar80T). The type species of the genus is Saccharolobus solfataricus. ·The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA and 23S rRNA gene sequences of strain HS-3T are LC275065 and LC27506, respectively.Sakellariadou, F., Antivachis, D., 2018. Spectroscopic studies of dissolved organic matter in a heavily modified Mediterranean and ancient coastal lake. Environmental Earth Sciences 77, 272. has a vital role in the environmental fate of numerous contaminants including trace metals and organic compounds. The aim of this research is the spectroscopic characterization of the DOM of sediment samples collected from the shoreline of a coastal and heavily modified Mediterranean lake, the appraisal of DOM nature and origin, the evaluation of impacts from lithology and land uses, the comparison of the relative effectiveness of spectroscopic approaches for chemical classification and the final combination of the results provided from each approach. UV–Vis absorption spectra suggest the presence of low molecular weight and a photochemical bleaching of chromophoric DOM. Spectral slope ratio had a negative correlation with autochthonous production and DOM molecular weight. Fluorescence spectra showed that DOM is mainly freshly produced and has an autochthonous origin. Chromophores are of a rather simple structure deriving from the degradation of plant components. The contribution of submerged springs in organic matter input was uncovered. FT-IR spectroscopy revealed the presence of aliphatic and aromatic chains. The presence of carboxylic, phenolic, alcoholic and polysaccharide groups was supported. A correlation of recent autochthonous material with relative depletion in hydroxyl, carboxyl, alcoholic and polysaccharide groups was found. The morphological particularity of the area with its permeable lithology and the presence of karstic springs, in combination with the land uses of the catchment area hosting heavy industrial, agricultural and urban activities, in addition to the high archaeological and ecological importance of the wetland and its surrounding area, may require the application of a sound management and environmental protection scheme.Salama, E.-S., Hwang, J.-H., El-Dalatony, M.M., Kurade, M.B., Kabra, A.N., Abou-Shanab, R.A.I., Kim, K.-H., Yang, I.-S., Govindwar, S.P., Kim, S., Jeon, B.-H., 2018. Enhancement of microalgal growth and biocomponent-based transformations for improved biofuel recovery: A review. Bioresource Technology 258, 365-375. biomass has received much attention as feedstock for biofuel production due to its capacity to accumulate a substantial amount of biocomponents (including lipid, carbohydrate, and protein), high growth rate, and environmental benefit. However, commercial realization of microalgal biofuel is a challenge due to its low biomass production and insufficient technology for complete utilization of biomass. Recently, advanced strategies have been explored to overcome the challenges of conventional approaches and to achieve maximum possible outcomes in terms of growth. These strategies include a combination of stress factors; co-culturing with other microorganisms; and addition of salts, flue gases, and phytohormones. This review summarizes the recent progress in the application of single and combined abiotic stress conditions to stimulate microalgal growth and its biocomponents. An innovative schematic model is presented of the biomass-energy conversion pathway that proposes the transformation of all potential biocomponents of microalgae into biofuels.Salimi, F., Ayatollahi, S., Seftie, M.V., 2018. Prediction of asphaltene deposition during turbulent flow using heat transfer approach. Petroleum Science and Technology 36, 632-639. this study, asphaltene deposition from crude oil has been studied experimentally using a test loop and prediction using theoretical study under turbulent flow (Reynolds numbers below 5000). The effects of many parameters such as oil velocity, surface temperature and concentration of flocculated asphaltene on the asphaltene deposition were investigated. The results showed that asphaltene deposition thickness increases with increasing both surface temperature and concentration of flocculated asphaltene and decreasing oil velocity. Thermal approach was used to describe the mechanisms involved in this process and the results of data fitting showed that there are good agreements between the results of the proposed model and the measured asphaltene deposition rates.Salmi-Laouar, S., Ferré, B., Chaabane, K., Laouar, R., Boyce, A.J., Fallick, A.E., 2018. The oceanic anoxic event 2 at Es Souabaa (Tebessa, NE Algeria): bio-events and stable isotope study. Arabian Journal of Geosciences 11, Article 182. the southern margin of the Tethys, the Es Souabaa area recorded traces of Oceanic Anoxic Event 2 (OAE2) around the Cenomanian-Turonian boundary (C/Tb). The dark, laminated, filament- and pyrite-bearing limestones represent the typical facies of this event. In terms of sedimentary environment, these features reflect a transgressive drowning that had induced hypoxia in these sedimentary environments. Such conditions favored the deposition and preservation of organic matter of marine origin, the distribution of which was controlled by paleogeography and halokinetic tectonics at that period. The OAE2 reached a climax between the last upper Cenomanian occurrence of Rotalipora cushmani and the lower Turonian occurrence of Whiteinella praehelvetica. Positive shift of the δ13C excursion along with relatively high total organic carbon (TOC) contents during OAE2 both indicate palaeo-environmental modifications enhanced by a significant change in primary marine productivity. Meanwhile, negative δ18O peaks in carbonates reflect increasing temperatures. Comparison of the data from this study with those from the neighboring Kalaat Senan section (Tunisia) suggests close similarities of events, although OAE2 is much more enhanced in Algeria.Samanipour, S., Reid, M.J., B?k, K., Thomas, K.V., 2018. Combining a deconvolution and a universal library search algorithm for the nontarget analysis of data-independent acquisition mode liquid chromatography?high-resolution mass spectrometry results. Environmental Science & Technology 52, 4694-4701. analysis is considered one of the most comprehensive tools for the identification of unknown compounds in a complex sample analyzed via liquid chromatography coupled to high-resolution mass spectrometry (LC–HRMS). Due to the complexity of the data generated via LC–HRMS, the data-dependent acquisition mode, which produces the MS2 spectra of a limited number of the precursor ions, has been one of the most common approaches used during nontarget screening. However, data-independent acquisition mode produces highly complex spectra that require proper deconvolution and library search algorithms. We have developed a deconvolution algorithm and a universal library search algorithm (ULSA) for the analysis of complex spectra generated via data-independent acquisition. These algorithms were validated and tested using both semisynthetic and real environmental data. A total of 6000 randomly selected spectra from MassBank were introduced across the total ion chromatograms of 15 sludge extracts at three levels of background complexity for the validation of the algorithms via semisynthetic data. The deconvolution algorithm successfully extracted more than 60% of the added ions in the analytical signal for 95% of processed spectra (i.e., 3 complexity levels multiplied by 6000 spectra). The ULSA ranked the correct spectra among the top three for more than 95% of cases. We further tested the algorithms with 5 wastewater effluent extracts for 59 artificial unknown analytes (i.e., their presence or absence was confirmed via target analysis). These algorithms did not produce any cases of false identifications while correctly identifying ～70% of the total inquiries. The implications, capabilities, and the limitations of both algorithms are further discussed.Samperio-Ramos, G., González-Dávila, M., Santana-Casiano, J.M., 2018. Impact on the Fe redox cycling of organic ligands released by Synechococcus PCC 7002, under different iron fertilization scenarios. Modeling approach. Journal of Marine Systems 182, 67-78. kinetics of Fe redox transformations are of crucial importance in determining the bioavailability of iron, due to inorganic Fe(II) and Fe weakly organic complexes being the most easily assimilated species by phytoplankton. The role played by the natural organic ligands excreted by the cyanobacteria Synecococcus PCC 7002 on the iron redox chemistry was studied at different stages of growth, considering changes in the organic exudation of the cyanobacteria, associated with growth under two different scenarios of iron availability. The oxidation/reduction processes of iron were studied at nanomolar levels and under different physicochemical conditions of pH (7.2–?8.2), temperature (5–?35?°C) and salinity (10–?37).The presence of natural organic exudates of Synechococcus affected the redox behavior of iron. A pH-dependent and photo-induced Fe(III) reduction process was detected in the presence of exudates produced under Fe-Low conditions. Photolytic reactions also modified the reactivity of those exudates with respect to Fe(II), increasing its lifetime in seawater. Without light mediated processes, organic ligands excreted under iron deficient conditions intensified the Fe(II) oxidation at pH?<?7.5. The organic exudates released under High-Fe conditions retarded the Fe(II) oxidation rate, as a function of DOC produced. The changes in the apparent oxidation rate were fitted to polynomial functions for both of the Fe-scenarios considered.A kinetic modeling approach to describe the speciation and the contribution of individual Fe(II) species to the overall oxidation rate was applied, considering the experimental data and delimiting the equilibrium and redox constants between iron and the major ligands present in solution. Two organic type ligands for the exudates of Synechococcus PCC 7002, with different iron-chelation properties were included in the model. The Fe(II) speciation was radically affected when organic ligands were considered. The individual contributions to the overall Fe(II) oxidation rate demonstrated that these organic ligands played a key role in the oxidation process, although their contributions were dependent on the prescribed iron conditions. The study, therefore, suggests that the variability in the composition and nature of organic exudates released, due to iron availability conditions, might determine the redox behaviour of iron in seawater.Sánchez-Illana, ?., Pi?eiro-Ramos, J.D., Sanjuan-Herráez, J.D., Vento, M., Quintás, G., Kuligowski, J., 2018. Evaluation of batch effect elimination using quality control replicates in LC-MS metabolite profiling. Analytica Chimica Acta 1019, 38-48. variation of the instrument's response both within- and between-batches is frequently observed in untarget LC-MS metabolomics involving the analysis of a large number of samples. The so-called batch effect decreases the statistical power and has a negative impact on repeatability and reproducibility of the results. As there is no standard way of assessing or correcting LC-MS batch effects and there is no single method providing optimal results in all situations, the selection of the optimal approach is not trivial. This work explores the effectiveness of a set of tools for batch effect assessment. Qualitative tools include the monitoring of spiked internal standards, principal component analysis and hierarchical cluster analysis. Quantitative tools comprise the distribution of RSDQC values, the median Pearson correlation coefficient in QCs, the ratio of random features in QCs using the runs test, as well as multivariate tools such as the δ-statistic, Silhouette plots, Principal Variance Component Analysis and the expected technical variation in the prediction. Results show that qualitative and quantitative approaches are complementary and that by limiting the analysis to QCs the power to detect and evaluate both within and between batch effects is increased. Besides, the graphical integration of outputs from multiple quantitative tools facilitates the evaluation of batch effects and it is proposed as a straightforward way for comparing and tailoring batch effect elimination approaches.Sandrin, T.R., Demirev, P.A., 2018. Characterization of microbial mixtures by mass spectrometry. Mass Spectrometry Reviews 37, 321-349. applications in microbiology have increased significantly in the past 10 years, due in part to the proliferation of regulator?approved commercial MALDI MS platforms for rapid identification of clinical infections. In parallel, with the expansion of MS technologies in the ?omics? fields, novel MS?based research efforts to characterize organismal as well as environmental microbiomes have emerged. Successful characterization of microorganisms found in complex mixtures of other organisms remains a major challenge for researchers and clinicians alike. Here, we review recent MS advances toward addressing that challenge. These include sample preparation methods and protocols, and established, for example, MALDI, as well as newer, for example, atmospheric pressure ionization (API) techniques. MALDI mass spectra of intact cells contain predominantly information on the highly expressed house?keeping proteins used as biomarkers. The API methods are applicable for small biomolecule analysis, for example, phospholipids and lipopeptides, and facilitate species differentiation. MS hardware and techniques, for example, tandem MS, including diverse ion source/mass analyzer combinations are discussed. Relevant examples for microbial mixture characterization utilizing these combinations are provided. Chemometrics and bioinformatics methods and algorithms, including those applied to large scale MS data acquisition in microbial metaproteomics and MS imaging of biofilms, are highlighted. Select MS applications for polymicrobial culture analysis in environmental and clinical microbiology are reviewed as well.Sanguinito, S., Goodman, A., Tkach, M., Kutchko, B., Culp, J., Natesakhawat, S., Fazio, J., Fukai, I., Crandall, D., 2018. Quantifying dry supercritical CO2-induced changes of the Utica Shale. Fuel 226, 54-64., shale formations have been studied as sealing layers that prevent vertical migration of hydrocarbons and CO2 due to their low permeability and fracture porosity. Recent research has focused on storing CO2 in hydrocarbon-bearing shale formations that have already undergone depletion through primary production and using CO2 as a potential fracturing agent for unconventional reservoirs. The injected CO2 will interact with shale components (i.e. clays, organic matter) and affect rock properties through chemical alteration, matrix swelling/shrinkage, and related geomechanical effects. As changes in rock properties will impact both anthropogenic CO2 storage and hydraulic fracturing, it is imperative to increase our understanding of the CO2-shale interactions. In-situ Fourier Transform infrared (FT-IR) spectroscopy coupled with high temperature and pressure capability was used to examine the interaction of dry CO2 on Utica Shale, clay, and kerogen samples at the molecular scale and characterize vibrational changes of sorption bands sensitive to the gas-solid environment. The Utica Shale was also analyzed for micro and macro-scale chemical and physical changes before and after exposure to dry CO2 at subsurface storage conditions using surface relocation techniques via high-resolution field-emission scanning electron microscopy (FE-SEM). Brunauer-Emmett-Teller (BET) surface area/pore size analysis and quantitative adsorption isotherms were applied to understand changes in surface area, pore volumes, and understand the storage potential of CO2 in the Utica Shale sample. FT-IR and feature relocation via FE-SEM indicate carbonate formation and dissolution occurs in shale exposed to dry CO2. Results indicate that etching and pitting occur, with minor calcite precipitation along the surface of the shale sample. Quantitative isotherm results indicate that shales with a higher content of kerogen and illite-smectite clays would be expected to have the highest CO2 storage capacity provided these constituents were accessible for interaction.Sarkar, P., Kumar, A., Singh, K.H., Ghosh, R., Singh, T.N., 2018. Pore system, microstructure and porosity characterization of Gondwana shale of Eastern India using laboratory experiment and watershed image segmentation algorithm. Marine and Petroleum Geology 94, 246-260. is the most crucial parameter to assess the potential of fine grain rocks like shale. Shale has very low connected porosity and permeability, which controls the fluid flow and migration. Therefore, detection of connected and closed pore network in digital images can help to evaluate porosity and permeability of rock. The objective of this paper is to characterize Gondwana shale of eastern India in micro-scale, that is, in terms of its porosity, pore-structure and pore size distribution for its shale gas potential. Watershed-transform has been performed to segment pores, throat and mineral grains by using 2-D Scan Electron Microscopy (SEM) images of Gondwana shale of Barren-Measures Formation. The watershed transform, when coupled with morphological operators and a customized disk shape structuring element, segments the pores and throats efficiently and estimates the porosity of Gondwana shale for the very first time. Three Gondwana shale samples from different borehole depth is used for this study. Finally, porosity measured in a laboratory using Mercury Injection Capillary Pressure (MICP) test, is compared with the numerically modeled watershed porosity values, which shows good agreement between the two sets of results with precisely segmented pore bodies and throat bodies at appropriate locations. Most of the pores in the sample are found to be in a mesopore category (2–50?nm). The porosity values measured using MICP ranges from 5.01% to 6.53% whereas the porosity estimated from watershed image segmentation ranges from 5.21% to 6.91%.Schenk, F., V?liranta, M., Muschitiello, F., Tarasov, L., Heikkil?, M., Bj?rck, S., Brandefelt, J., Johansson, A.V., N?slund, J.-O., Wohlfarth, B., 2018. Warm summers during the Younger Dryas cold reversal. Nature Communications 9, Article 1634. Younger Dryas (YD) cold reversal interrupts the warming climate of the deglaciation with global climatic impacts. The sudden cooling is typically linked to an abrupt slowdown of the Atlantic Meridional Overturning Circulation (AMOC) in response to meltwater discharges from ice sheets. However, inconsistencies regarding the YD-response of European summer temperatures have cast doubt whether the concept provides a sufficient explanation. Here we present results from a high-resolution global climate simulation together with a new July temperature compilation based on plant indicator species and show that European summers remain warm during the YD. Our climate simulation provides robust physical evidence that atmospheric blocking of cold westerly winds over Fennoscandia is a key mechanism counteracting the cooling impact of an AMOC-slowdown during summer. Despite the persistence of short warm summers, the YD is dominated by a shift to a continental climate with extreme winter to spring cooling and short growing seasons.Schilder, J., van Roij, L., Reichart, G.-J., Sluijs, A., Heiri, O., 2018. Variability in δ13C values between individual Daphnia ephippia: Implications for palaeo-studies. Quaternary Science Reviews 189, 127-133. stable carbon isotope ratio (δ13C value) of Daphnia spp. resting egg shells (ephippia) provides information on past changes in Daphnia diet. Measurements are typically performed on samples of ≥20 ephippia, which obscures the range of values associated with individual ephippia. Using a recently developed laser ablation-based technique, we perform multiple δ13C analyses on individual ephippia, which show a high degree of reproducibility (standard deviations 0.1–0.5‰). We further measured δ13C values of 13 ephippia from surface sediments of three Swiss lakes. In the well-oxygenated lake with low methane concentrations, δ13C values are close to values typical for algae (?31.4‰) and the range in values is relatively small (5.8‰). This variability is likely driven by seasonal (or inter-annual) variability in algae δ13C values. In two seasonally anoxic lakes with higher methane concentrations, average values were lower (?41.4 and ?43.9‰, respectively) and the ranges much larger (10.7 and 20.0‰). We attribute this variability to seasonal variation in incorporation of methane-derived carbon. In one lake we identify two statistically distinct isotopic populations, which may reflect separate production peaks. The potentially large within-sample variability should be considered when interpreting small-amplitude, short-lived isotope excursions based on samples consisting of few ephippia. We show that measurements on single ephippia can be performed using laser ablation, which allows for refined assessments of past Daphnia diet and carbon cycling in lake food webs. Furthermore, our study provides a basis for similar measurements on other chitinous remains (e.g. from chironomids, bryozoans).Schüpbach, S., Fischer, H., Bigler, M., Erhardt, T., Gfeller, G., Leuenberger, D., Mini, O., Mulvaney, R., Abram, N.J., Fleet, L., Frey, M.M., Thomas, E., Svensson, A., Dahl-Jensen, D., Kettner, E., Kjaer, H., Seierstad, I., Steffensen, J.P., Rasmussen, S.O., Vallelonga, P., Winstrup, M., Wegner, A., Twarloh, B., Wolff, K., Schmidt, K., Goto-Azuma, K., Kuramoto, T., Hirabayashi, M., Uetake, J., Zheng, J., Bourgeois, J., Fisher, D., Zhiheng, D., Xiao, C., Legrand, M., Spolaor, A., Gabrieli, J., Barbante, C., Kang, J.H., Hur, S.D., Hong, S.B., Hwang, H.J., Hong, S., Hansson, M., Iizuka, Y., Oyabu, I., Muscheler, R., Adolphi, F., Maselli, O., McConnell, J., Wolff, E.W., 2018. Greenland records of aerosol source and atmospheric lifetime changes from the Eemian to the Holocene. Nature Communications 9, Article 1476. Northern Hemisphere experienced dramatic changes during the last glacial, featuring vast ice sheets and abrupt climate events, while high northern latitudes during the last interglacial (Eemian) were warmer than today. Here we use high-resolution aerosol records from the Greenland NEEM ice core to reconstruct the environmental alterations in aerosol source regions accompanying these changes. Separating source and transport effects, we find strongly reduced terrestrial biogenic emissions during glacial times reflecting net loss of vegetated area in North America. Rapid climate changes during the glacial have little effect on terrestrial biogenic aerosol emissions. A strong increase in terrestrial dust emissions during the coldest intervals indicates higher aridity and dust storm activity in East Asian deserts. Glacial sea salt aerosol emissions in the North Atlantic region increase only moderately (50%), likely due to sea ice expansion. Lower aerosol concentrations in Eemian ice compared to the Holocene are mainly due to shortened atmospheric residence time, while emissions changed little.Schwarz, A., Adetutu, E.M., Juhasz, A.L., Aburto-Medina, A., Ball, A.S., Shahsavari, E., 2018. Microbial degradation of phenanthrene in pristine and contaminated sandy soils. Microbial Ecology 75, 888-902. mineralisation studies in both pristine and contaminated sandy soils were undertaken through detailed assessment of the activity and diversity of the microbial community. Stable isotope probing (SIP) was used to assess and identify active 13C-labelled phenanthrene degraders. Baseline profiling indicated that there was little difference in fungal diversity but a significant difference in bacterial diversity dependent on contamination history. Identification of dominant fungal and bacterial species highlighted the presence of organisms capable of degrading various petroleum-based compounds together with other anthropogenic compounds, regardless of contamination history. Community response following a simulated contamination event (14C-phenanthrene) showed that the microbial community in deep pristine and shallow contaminated soils adapted most to the presence of phenanthrene. The similarity in microbial community structure of well-adapted soils demonstrated that a highly adaptable fungal community in these soils enabled a rapid response to the introduction of a contaminant. Ten fungal and 15 bacterial species were identified as active degraders of phenanthrene. The fungal degraders were dominated by the phylum Basidiomycota including the genus Crypotococcus, Cladosporium and Tremellales. Bacterial degraders included the genera Alcanivorax, Marinobacter and Enterococcus. There was little synergy between dominant baseline microbes, predicted degraders and those that were determined to be actually degrading the contaminant. Overall, assessment of baseline microbial community in contaminated soils provides useful information; however, additional laboratory assessment of the microbial community’s ability to degrade pollutants allows for better prediction of the bioremediation potential of a soil.Sciarra, A., Mazzini, A., Inguaggiato, S., Vita, F., Lupi, M., Hadi, S., 2018. Radon and carbon gas anomalies along the Watukosek Fault System and Lusi mud eruption, Indonesia. Marine and Petroleum Geology 90, 77-90. extensive survey was carried out in the Sidoarjo district (East Java, Indonesia) to investigate the gas leaking properties along fractured zones coinciding with a strike-slip system, the Watukosek Fault System (WFS) in NE Java. This structure has been the focus of attention since the beginning of the spectacular Lusi mud eruption on the 29th May 2006. The sinistral strike-slip WFS originates from the Arjuno-Welirang volcanic complex, intersects the active Lusi eruption site displaying a system of antithetic faults, and extends towards the NE of Java where mud volcanic structures reside. In the Lusi region we completed a geochemical survey along three profiles combining measurements of a) 220Rn and 222Rn activity, b) CO2 and CH4 soil gas content, c) CO2 and CH4 fluxes, and d) gas analyses. The profiles are up to ～1.2?km long and intersect perpendicularly areas with intense fracturing and surface deformation along the WFS. The purpose was to investigate the presence and origin of soil degassing activity in potentially active fault zones. Results show that the peripheral sectors of the profiles have high 220Rn activity and reduced CO2 and CH4 fluxes and concentrations. This suggests low fluids migration that could be affected by shallow circulation. In contrast, the segments of profiles intersecting the fractured zones have the highest 222Rn activity, CO2 and CH4 flux and gas concentration values. The relationship existing among the measured parameters suggests that the WFS acts as a preferential pathway for active rise of deep fluids. The presence of such advective processes is suggested by the relatively high rate of migration needed to obtain anomalies of short-lived 222Rn in the soil pores. Gas molecular and isotopic composition reveals that all sampled localities have a mixed hydrocarbon origin implying the presence of shallow microbial and deeper thermogenic hydrocarbons. CO2 isotopic values (δ13C-CO2 ranges between??9.48‰ and 4.12‰ V-PDB) indicate the presence of mantle derived CO2 and thermo-metamorphic CO2 suggesting that elevated temperatures have a key role in this active system. The samples collected from fractured and faulted zones reveal to have gas composition similar to that obtained from Lusi crater, indicating deep origin fluids.Scott, D.A., 2018. Egyptian sarcophagi and mummies in the San Diego Museum of Man: Some technical studies. Studies in Conservation 63, 215-235. ancient Egyptian sarcophagi of the twenty-fifth to twenty-sixth dynasty, one Ptolemaic Hawk Mummy, and one Amarna fresco were examined in the collections of the San Diego Museum of Man. Binding media, pigments, wood identification, deterioration and alteration products were identified. The pigment palette represents the basic suite of ancient Egyptian pigments: charcoal black, red ochre, yellow ochre, Egyptian blue, green earth, calcite, and gypsum. In the case of the Hawk mummy, oxammite was identified as a degradation product, together with magnesium phosphate, the first identification of oxammite in ancient artefacts. In a child?s coffin, realgar and orpiment were additionally identified. The binding media for practically all of the coffins studied was confirmed as gum Arabic with only one example of gum tragacanth found from a wall plaque from Amarna. Wood identification showed that Ficus sycomorus had been used, rather than the assumed cedar of Lebanon for coffin manufacture. One unidentified species of shrubby wood was also found. Some of the coffins had been restored, with one having a completely repainted face, in rutile, and the child?s coffin has an attached foot-box with modern screws. Possible indications of ancient reuse were found during the study.Scott, R.W., Oboh-Ikuenobe, F.E., Benson Jr, D.G., Holbrook, J.M., Alnahwi, A., 2018. Cenomanian-Turonian flooding cycles: U.S. Gulf Coast and Western Interior. Cretaceous Research 89, 191-210. ages, 100.5 Ma to 89.8 Ma, represented an extraordinary Cretaceous time interval when continental seaways expanded, tropical waters interchanged with Polar waters, global climates warmed, and at the end of the Cenomanian large amounts of organic carbon were buried. This was a time of major evolutionary changes in marine pelagic and benthic ecosystems, and in terrestrial plant ecosystems. A new comprehensive chronostratigraphic Cretaceous database is built upon reference sections of each Cretaceous stage and is calibrated to the 2016 Geologic Time Scale. This database is composed of bioevents, chemostratigraphic events, radioisotope measurements, and magnetochrons integrated with nearly 3000 species by projecting the section measurements of the events to the numeric time scale.This new database calibrates numerical ages of Cenomanian-Turonian sequence boundaries in Tunisian reference sections. These deep-shelf successions of limestone/marl/shale record biostratigraphically well dated, continuous deposition and serve as a model of Cenomanian-Turonian cycles. The Cretaceous database enables stratigraphic correlation experiments to test the time equivalency of Tunisian depositional cycles with sequences in Europe, in the Eagle Ford Group in Texas and with stratigraphic sequences in the Western Interior. New accurate and precise correlation of Cenomanian-Turonian depositional sequences between the Gulf Coast and the Western Interior test new biostratigraphic and radioisotopic data of the Eagle Ford Group on the Texas Comanche shelf. The Albian-Cenomanian boundary as defined by planktic foraminifers and ammonites in Texas projects between upper Albian shale units and the Dakota Group and associated sandstone units. The Mowry Shale and its endemic ammonites correlate with upper lower Cenomanian zones.Seligmann, H., 2018. Bijective codon transformations show genetic code symmetries centered on cytosine’s coding properties. Theory in Biosciences 137, 17-31. of some RNAs with template DNA requires systematic exchanges between nucleotides. Such exchanges produce ‘swinger’ RNA along 23 bijective transformations (nine symmetric, X???Y; and 14 asymmetric, X?→?Y?→?Z?→?X, for example A???C and A?→?C?→?G?→?A, respectively). Here, analyses compare amino acids coded by swinger-transformed codons to those coded by untransformed codons, defining coding invariance after transformations. Swinger transformations cluster according to coding invariance in four groups characterized by transformations into cytosine (C?=?C, T?→?C, A?→?C, and G?→?C). C’s central mutational coding role shows that swinger transformations constrained genetic code genesis. Coding invariance post-transformations correlate positively/negatively with mitochondrial swinger transcription/lepidosaurian body temperature. Presumably, low/high temperatures stabilize/revert rare swinger polymerization modes, producing long swinger sequences/point mutations, respectively. Coding invariance after swinger transformations might compensate effects of swinger polymerizations in species with low body temperatures. Hypothetically, swinger transcription increased coding potential of RNA self-replicating protolife systems under heating/cooling cycles.Sepanian, E., Sepahy, A.A., Hosseini, F., 2018. Isolation and characterization of bacterial species from Ain mud volcano, Iran. Microbiology 87, 282-289. the coastal belt of Makran, on the southeastern margin of Iran, there are several active and inactive mud volcanoes with different morphologies. Ain—an actively bubbling eye-shaped mud pool—is one of these unique geological phenomena. Present study indicates the first overview of the bacterial diversity of this mud volcano obtained by culture techniques. For this purpose, two samples were collected at two different depths of the mud pool and were cultivated on two different nutrient culture media. A total of 13 isolates were randomly chosen for further phenotypic and genotypic characterization. Growth of the isolates occurred at 25–42°C, pH 8–10 and 0–10% NaCl, indicating that most of them were haloalkaliphiles. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the bacterial isolates belonged to three major taxa: Gammaproteobacteria (genera: Marinobacter, Nitrincola, Stentrophomonas), Actinobactera (genera: Kocuria, Brevibacterium, Dietzia) and Firmicutes (genus Planomicrobium). Gammaproteobacteria were the most abundant, following Actinobacteria and Firmicutes. Most of the strains isolated in the present study had the ability to produce extracellular hydrolytic enzymes such as lipases, amylases, proteases and DNases, making them important biotechnologically.Shakeri, F., Darvish, H., Garmsiri, H., Bemani, A., 2018. Applying Fuzzy c-means approach as a novel method for prediction of interfacial tension between carbon dioxide and hydrocarbons. Petroleum Science and Technology 36, 648-653. worldwide demand for energy increases and also the price of crude oil increases so these reasons have been caused the searchers have motivated to investigate enhanced of oil recovery (EOR) processes. The carbon dioxide injection is recognized as one of the favorable approaches of EOR because of high displacement efficiency, environmentally aspects and lower cost. The Interfacial tension between crude oil and carbon dioxide is known as one of the critical factors which affect the performance of injection. The main objective of the present investigation is development of Fuzzy c-means (FCM) approach as novel method to estimate interfacial tension between carbon dioxide and hydrocarbons as function of pressure, temperature, liquid and gas densities and molecular weight of alkane. The performance of predicting model was evaluated statistically and graphically and the results confirmed the ability of the model to predict interfacial tension between carbon dioxide and hydrocarbons.Shan, C., Zhang, T., Liang, X., Zhang, Z., Wang, M., Zhang, K., Zhu, H., 2018. On the fundamental difference of adsorption-pores systems between vitrinite- and inertinite-rich anthracite derived from the southern Sichuan basin, China. Journal of Natural Gas Science and Engineering 53, 32-44. further understand the fundamental difference of adsorption-pores systems between vitrinite- and inertinite-rich anthracite, six coal core samples with >85% vitrinite and three samples with >80% inertinite were collected from coalbed methane wells in the southern Sichuan basin, China, by macerals analysis method. The differences of pore genetic types, pores shapes, pore surfaces, pore-size distribution, specific surface area, total pore volume, physical properties, and CH4 adsorption capacity between vitrinite- and inertinite-rich samples, were studied via ESEM observation, low-temperature N2 adsorption experiments, NMR tests, and CH4 isothermal adsorption experiments. Results show that plant tissue holes are easier to observe in inertinite than vitrinite, and blowholes, breccia pores and broken pores are all common in vitrinite and rare in inertinite of the study coals. Both vitrinite- and inertinite-rich coal samples exhibit complex nano-pore structures, and pore shapes in inertinite-rich coals are more special than those in vitrinite-rich samples. Fractal dimensions analysis from the N2 adsorption isotherms indicates that inertinite-rich coals have the higher surfaces roughness of irregular pores than vitrinite-rich coals in the P/Po intervals of 0.5–1. In addition, it can be predicted that pores of D2 and D3 type hysteresis loops with diameters of <2.76?nm each are almost semi-closed pores, and the narrow neck in “ink bottle” pores generally measure 2.76?nm. Nano-pores measuring <4?nm comprise the largest proportion among all adsorption-pores. The proportion of pores with diameters of <0.64?nm each in inertinite-rich coals is greater than that in vitrinite-rich coals. NMR porosities, permeabilities, and irreducible water saturations between vitrinite- and inertinite-rich coals are all similar, and the porosities display a good exponential positive correlation with the permeabilities. Vitrinite- and inertinite-rich samples are both characterized by a large VL, and there are positive relationships of VL with vitrinite and inertinite, indicating the CH4 adsorption capacity of organic macerals is much stronger than that of inorganic minerals in anthracite.Shank, E.A., 2018. Considering the lives of microbes in microbial communities. mSystems 3, DOI: 10.1128/mSystems.00155-17. the last decades, sequencing technologies have transformed our ability to investigate the composition and functional capacity of microbial communities. Even so, critical questions remain about these complex systems that cannot be addressed by the bulk, community-averaged data typically provided by sequencing methods. In this Perspective, I propose that future advances in microbiome research will emerge from considering “the lives of microbes”: we need to create methods to explicitly interrogate how microbes exist and interact in native-setting-like microenvironments. This approach includes developing approaches that expose the phenotypic heterogeneity of microbes; exploring the effects of coculture cues on cellular differentiation and metabolite production; and designing visualization systems that capture features of native microbial environments while permitting the nondestructive observation of microbial interactions over space and time with single-cell resolution.Sharma, H., Mohanty, K.K., 2018. An experimental and modeling study to investigate brine-rock interactions during low salinity water flooding in carbonates. Journal of Petroleum Science and Engineering 165, 1021-1039. of brines with carefully designed ionic compositions into oil-wet carbonate rocks at high temperatures has shown to alter their wettability towards a water-wet state and improve oil recovery. Various mechanisms have been postulated for this wettability alteration such as mineral dissolution and interaction of potential determining ions, such as Ca2+, Mg2+ and SO42?, with the carbonate surface. In this study, experimental and modeling work was performed to gain further insights into the geochemical interactions between carbonate rocks and modified brines. Single-phase static (equilibrium) and transport experiments were performed with various brines in limestone cores at 120?°C. The ionic compositions of the effluent samples were monitored using ion chromatography. A mechanistic model for the wettability alteration process was developed in UTCHEM-IPHREEQC based on key geochemical interactions. The calcite surface was assumed to consist of positive and negative sites and their interactions with potential determining ions were considered assuming local equilibrium. The model assumed the degree of oil-wetness to depend on the amount of organic acid attached on the surface, which in-turn was dependent on the geochemistry of the system. Results of static experiments performed with crushed limestones and brines showed an increase in calcium concentration and a decrease in magnesium concentration in the supernatant brines. The effluent concentrations from single-phase brine corefloods in limestone cores showed an increase in calcium concentration, a decrease in magnesium concentration and a delay in sulfate concentration. Three key geochemical interactions were identified based on these results: mineral dissolution, surface dolomitization and sulfate adsorption. A good qualitative agreement was observed between single-phase experiments and simulations, suggesting that the model was able to accurately capture the geochemistry. The simulation results showed good agreement with zeta potential and oil recovery results reported in the literature.Sharpe, A.E., Emery, K.F., Inomata, T., Triadan, D., Kamenov, G.D., Krigbaum, J., 2018. Earliest isotopic evidence in the Maya region for animal management and long-distance trade at the site of Ceibal, Guatemala. Proceedings of the National Academy of Sciences 115, 3605-3610.: The nature of animal management in Mesoamerica is not as well understood compared with other state-level societies around the world. In this study, isotope analysis of animal remains from Ceibal, Guatemala, provides the earliest direct evidence of live animal trade and possible captive animal rearing in the Maya region. Carbon, nitrogen, and oxygen isotopes show that domesticated and possibly even wild animals were raised in or around Ceibal and were deposited in the ceremonial core. Strontium isotope analysis reveals the Maya brought dogs to Ceibal from the distant Guatemalan highlands. The possible ceremonial contexts of these captive-reared and imported taxa suggests animal management played an important role in the symbolic development of political power.Abstract: This study uses a multiisotope (carbon, nitrogen, oxygen, and strontium) approach to examine early animal management in the Maya region. An analysis of faunal specimens across almost 2,000 years (1000 BC to AD 950) at the site of Ceibal, Guatemala, reveals the earliest evidence for live-traded dogs and possible captive-reared taxa in the Americas. These animals may have been procured for ceremonial functions based on their location in the monumental site core, suggesting that animal management and trade began in the Maya area to promote special events, activities that were critical in the development of state society. Isotopic evidence for animal captivity at Ceibal reveals that animal management played a greater role in Maya communities than previously believed.Sheik, C.S., Reese, B.K., Twing, K.I., Sylvan, J.B., Grim, S.L., Schrenk, M.O., Sogin, M.L., Colwell, F.S., 2018. Identification and removal of contaminant sequences from ribosomal gene databases: Lessons from the census of deep life. Frontiers in Microbiology 9, 840. doi: 10.3389/fmicb.2018.00840.’s subsurface environment is one of the largest, yet least studied, biomes on Earth, and many questions remain regarding what microorganisms are indigenous to the subsurface. Through the activity of the Census of Deep Life (CoDL) and the Deep Carbon Observatory, an open access 16S ribosomal RNA gene sequence database from diverse subsurface environments has been compiled. However, due to low quantities of biomass in the deep subsurface, the potential for incorporation of contaminants from reagents used during sample collection, processing, and/or sequencing is high. Thus, to understand the ecology of subsurface microorganisms (i.e., the distribution, richness, or survival), it is necessary to minimize, identify, and remove contaminant sequences that will skew the relative abundances of all taxa in the sample. In this meta-analysis, we identify putative contaminants associated with the CoDL dataset, recommend best practices for removing contaminants from samples, and propose a series of best practices for subsurface microbiology sampling. The most abundant putative contaminant genera observed, independent of evenness across samples, were Propionibacterium, Aquabacterium, Ralstonia, and Acinetobacter. While the top five most frequently observed genera were Pseudomonas, Propionibacterium, Acinetobacter, Ralstonia, and Sphingomonas. The majority of the most frequently observed genera (high evenness) were associated with reagent or potential human contamination. Additionally, in DNA extraction blanks, we observed potential archaeal contaminants, including methanogens, which have not been discussed in previous contamination studies. Such contaminants would directly affect the interpretation of subsurface molecular studies, as methanogenesis is an important subsurface biogeochemical process. Utilizing previously identified contaminant genera, we found that ～27% of the total dataset were identified as contaminant sequences that likely originate from DNA extraction and DNA cleanup methods. Thus, controls must be taken at every step of the collection and processing procedure when working with low biomass environments such as, but not limited to, portions of Earth’s deep subsurface. Taken together, we stress that the CoDL dataset is an incredible resource for the broader research community interested in subsurface life, and steps to remove contamination derived sequences must be taken prior to using this dataset.Shen, Y., Thiel, V., Duda, J.P., Reitner, J., 2018. Tracing the fate of steroids through a hypersaline microbial mat (Kiritimati, Kiribati/Central Pacific). Geobiology 16, 307-318. steranes are typically absent or occur in very low concentrations in Precambrian sedimentary rocks. However, it is as yet unclear whether this may reflect low source inputs or a preservational bias. For instance, it has been proposed that eukaryotic lipids were profoundly degraded in benthic microbial mats that were ubiquitous prior to the advent of vertical bioturbation in the Cambrian (“mat‐seal effect”). It is therefore important to test the microbial turnover and degradation of eukaryotic steroids in real‐world microbial mats. Here we assessed steroid inventories in different layers of a microbial mat from a hypersaline lake on Kiritimati (Central Pacific). Various eukaryote‐derived C27‐C30 steroids were detected in all mat layers. These compounds most likely entered the mat system as unsaturated sterols from the water column or the topmost mat, and were progressively altered during burial in the deeper, anoxic mat layers over c. 103 years. This is reflected by increasing proportions of saturated sterols and sterenes, as well as the presence of thiosteranes in certain horizons. Sterol alteration can partly be assigned to microbial transformation but is also due to chemical reactions promoted by the reducing environment in the deeper mat layers. Notably, however, compounds with a sterane skeleton were similarly abundant in all mat layers and their absolute concentrations did not show any systematic decrease. The observed decrease of steroid/hopanoid ratios with depth may thus rather indicate a progressive “dilution” by lipids derived from heterotrophic bacteria. Further, pyrolysis revealed that steroids, in contrast to hopanoids, were not sequestered into non‐extractable organic matter. This may lead to a preservational bias against steroids during later stages of burial. Taken together, steroid preservation in the microbial mat is not only controlled by heterotrophic degradation, but rather reflects a complex interplay of taphonomic processes.Sheng, Q., Wang, G., Liu, Y., Husein, M.M., Gao, C., Shi, Q., Gao, J., 2018. Combined hydrotreating and fluid catalytic cracking processing for the conversion of inferior coker gas oil: Effect on nitrogen compounds and condensed aromatics. Energy & Fuels 32, 4979-4987. coker gas oil (ICGO) derived from Venezuelan vacuum residue delayed coking is difficult to process using fluid catalytic cracking (FCC) or hydrocracking (HDC). The high content of nitrogen and condensed aromatics leads to major coking and readily deactivates the acid catalyst. In this work, a sequence of hydrotreating (HDT) and FCC processing is used to effectively convert ICGO to a high-value light oil product. The results show a higher overall conversion and a significant increase in the yield of gasoline compared to FCC processing. Molecular level characterization of the nitrogen compounds and condensed aromatics before and after HDT confirms that the nitrogen content and the 2+-ring aromatic content decreased, whereas the single-ring aromatics increased. The nitrogen compounds were mainly N1, N1O1, N1O2, and N1S1 class species in basic nitrogen and N1, N1O1, N1O2, N2, and N2O1 class species in non-basic nitrogen. Moreover, the double bond equivalent of these species shifted to lower values. The decrease in the nitrogen compounds with a high heteroatom content reduces coking on the FCC catalyst. Subsequently, FCC unit performance and conversion to light oil increased. Moreover, the decrease in the size of N1 class compounds and the ease of their cracking following HDT improved the performance of the FCC unit. Partial saturation of condensed aromatics following HDT also made it easier to crack these compounds.Shi, C., Cao, J., Tan, X., Luo, B., Zeng, W., Hong, H., Huang, X., Wang, Y., 2018. Hydrocarbon generation capability of Sinian–Lower Cambrian shale, mudstone, and carbonate rocks in the Sichuan Basin, southwestern China: Implications for contributions to the giant Sinian Dengying natural gas accumulation. American Association of Petroleum Geologists Bulletin 102, 817-853. giant natural gas accumulation recently discovered within the (Neoproterozoic) Dengying Formation in the Sichuan Basin of southwestern China represents a new and important supplement to the ancient Neoproterozoic–Cambrian petroleum systems worldwide. However, the source of this gas is controversial because there are five possibilities based on geology, from bottom to top including the Lower Sinian Doushantuo mudstone, the Upper Sinian Dengying algal dolomite, the mudstone of the third member of the Dengying Formation, the Lower Cambrian Maidiping argillaceous dolomite, and the Lower Cambrian Qiongzhusi shale. To improve the understanding of this issue, 33 samples from the five possible source rock units in the study area were investigated for their character and maturity via petrology, total organic carbon (TOC), pyrobitumen reflectance, kerogen carbon isotope, and biomarker analyses. Based on the results, we address their hydrocarbon generation capabilities and contributions to the giant gas accumulation. Results show that present-day TOC values of the samples range from 0.03% to 2.36% and vary both regionally and stratigraphically, with the Qiongzhusi shales in the central basin and the Weiyuan–Ziyang area ranking the highest. In contrast, the organic matter source and maturity within these rocks are relatively homogenous with slight variation throughout the study area. The organic matter is predominantly derived from algae and bacteria with different compositions deposited in marine reducing environments. The rocks range in thermal maturity from postmature to overmature. These results imply that the generation capability of source rock had been high in the past, and the gas in the study area is most likely originated from oil cracking and the late generation directly from the kerogen of source rocks, with the Qiongzhusi shales being the dominant source rock. Thus, the hydrocarbon migration pattern in the study area is a lateral migration from deep-seated and younger Cambrian source rocks in sags to shallow-seated and older Sinian dolomite reservoirs in uplifts. The migration process occurred in the oil phase with the oil being later cracked. The differences in natural gas geochemistry may be controlled by complex factors, e.g., thermal maturity, the migration–accumulation process, and differing contributions from source rocks besides the dominant Qiongzhusi. Regionally, the central basin and the Weiyuan–Ziyang area have had high hydrocarbon generation capability and thus should be considered as favorable targets for natural gas exploration in the future. This study of China provides an additional example of Neoproterozoic–Cambrian petroleum systems worldwide and thus can help to synthesize the systematics of such systems and understand the sedimentary transition across the Precambrian–Cambrian boundary.Shi, M., Yu, B., Zhang, J., Huang, H., Yuan, Y., Li, B., 2018. Microstructural characterization of pores in marine shales of the Lower Silurian Longmaxi Formation, southeastern Sichuan Basin, China. Marine and Petroleum Geology 94, 166-178. the complexities of sedimentary pore systems is the key to understanding the mechanisms that lead to shale gas accumulation. In this study, the microstructures, networks, and connectivity of pores in marine shales of the Longmaxi Formation in the southeastern Sichuan Basin are investigated using a combination of qualitative and quantitative methods. 2D and 3D characterizations of the formation provide an opportunity to describe the types of pores, pore networks and pore connectivity in these shales. The study's results show that nearly all pores are nanosized and that organic matter (OM) pores are the most common but also include interparticle (InterP) pores, intraparticle (IntraP) pores and micro-fracture pores. Reconstructed 3D models show that there is limited connectivity of pores. Gas adsorption analysis and statistical results indicate that nearly 95% of the pores are micro-to meso-scale and account for approximately 23% and 73% of the pore space, respectively. A combination of image processing and calculations also shows that OM pores account for approximately 87% of all pores, and as such, the pore networks are dominated by OM pores. OM pores are associated with discontinuous occurrences of organic matter, which results in relatively poor connectivity.Shi, Q., Qin, B., Bi, Q., Qu, B., 2018. An experimental study on the effect of igneous intrusions on chemical structure and combustion characteristics of coal in Daxing Mine, China. Fuel 226, 307-315. investigate the effect of igneous intrusions on the structure and combustion characteristics of coal, the normal bituminous coal and thermally altered coal were collected from Daxing Mine in China. The chemical structural features of coal were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Structural parameters determined from XRD analyses, including the interlayer spacing of the crystallite (d002), stacking height (Lc), aromaticity (fa(XRD)), and coal rank (RXRD), revealed that the altered coal showed more crystalline carbon and higher coal rank than the normal bituminous coal. FTIR analyses indicated that igneous intrusions increased the apparent aromaticity of the altered coal and elevated its maturation level, which was consistent with the XRD results. TG-DSC experiments were conducted to study the combustion characteristics of coal. The result showed that the combustion process of the altered coal was delayed to high-temperature region. Compared with the normal coal, the altered coal exhibited lower combustion reactivity and worse combustion performance, as evidenced by lower comprehensive combustion index, higher ignition temperature and burnout temperature, as well as larger apparent activation energy. Moreover, igneous intrusions decreased the heat release and calorific value of the altered coal during combustion, which was ascribed to the changes in chemical composition and structure of the altered coal. This study concluded that igneous intrusions increased the difficulty in igniting the altered coals and reduced its heat release during combustion.Shi, X., Yang, W., Qiu, S., Hou, J., Wu, W., Guo, D., 2018. Systematic profiling and comparison of the lipidomes from Panax ginseng, P. quinquefolius, and P. notoginseng by ultrahigh performance supercritical fluid chromatography/high-resolution mass spectrometry and ion mobility-derived collision cross section measurement. Journal of Chromatography A 1548, 64-75. currently is still confronted with challenges from chromatographic separation and lipids identification. Here we report a lipidomics platform by integrating ultrahigh performance supercritical fluid chromatography/quadrupole time-of-flight mass spectrometry (UHPSFC/QTOF-MS) and collision cross section (CCS) measurement using ion mobility spectroscopy/time-of-flight mass spectrometry (IMS/QTOF-MS), aiming to enhance the profiling performance and identification reliability of lipids. The lipidomes extracted from three congeneric Panax species (P. ginseng, P. quinquefolius, and P. notoginseng) by methyl tert-butyl ether are comprehensively profiled and compared by use of this platform. A potent UHPSFC/QTOF-MS approach was developed on a 1.7-μm particles packed Torus 2-PIC column using CH3OH (in CO2) as a modifier and CH3OH/0.2?mM ammonium acetate as the makeup liquid, enabling well resolution of six lipid subclasses by both positive and negative MSE modes. In contrast to the reversed-phase chromatography, “normal-phase” like elution order and better resolution of polar lipids and some lipid isomers were achieved by UHPSFC separation. Pattern recognition chemometric analysis of 60 batches of Ginseng samples ultimately unveiled 24 lipid markers, of which triacylglycerols were the most important. Aside from the automated MS database searching against HMDB and LIPID MAPS, the application of CCS retrieval or CCS prediction improved lipid identification by reducing the possible hits. In conclusion, this integral platform can significantly improve the chromatographic separation and the reliability of lipids identification in lipidomics studies. It is the first report that systematically compares the lipidomic difference of three reputable Panax species, providing useful information for their quality control in addition to ginsenoside analysis.Shi, Z., Qiu, Z., Dong, D., Lu, B., Liang, P., Zhang, M., 2018. Lamina characteristics of gas-bearing shale fine-grained sediment of the Silurian Longmaxi Formation of Well Wuxi 2 in Sichuan Basin, SW China. Petroleum Exploration and Development 45, 358-368. on various test data, the composition, texture, structure and lamina types of gas-bearing shale were determined based on Well Wuxi 2 of the Silurian Longmaxi Formation in the Sichuan Basin. Four types of lamina, namely organic-rich lamina, organic-bearing lamina, clay lamina and silty lamina, are developed in the Longmaxi Formation of Well Wuxi 2, and they form 2 kinds of lamina set and 5 kinds of beds. Because of increasing supply of terrigenous clasts and enhancing hydrodynamics and associated oxygen levels, the contents of TOC and brittle mineral reduce and content of clay mineral increases gradually as the depth becomes shallow. Organic-rich lamina, organic-rich + organic-bearing lamina set and organic-rich bed dominate the small layers 1-3 of Member 1 of the Longmaxi Formation, suggesting anoxic and weak hydraulic depositional setting. Organic-rich lamina, along with organic-bearing lamina and silty lamina, appear in small layer 4, suggesting increased oxygenated and hydraulic level. Small layers 1-3 are the best interval and drilling target of shale gas exploration and development.Shields-Menard, S.A., Amirsadeghi, M., French, W.T., Boopathy, R., 2018. A review on microbial lipids as a potential biofuel. Bioresource Technology 259, 451-460. security, environmental concerns, and unstable oil prices have been the driving trifecta of demand for alternative fuels in the United States. The United States’ dependence on energy resources, often from unstable oil-producing countries has created political insecurities and concerns. As we try to gain energy security, unconventional oil becomes more common, flooding the market, and causing the major downshift of the usual unstable oil prices. Meanwhile, consumption of fossil fuels and the consequent CO2 emissions have driven disruptions in the Earth’s atmosphere and are recognized to be responsible for global climate change. While the significance of each of these three factors may fluctuate with global politics or new technologies, transportation energy will remain the prominent focus of multi-disciplined research. Bioenergy future depends on the price of oil. Current energy policy of the United States heavily favors petroleum industry. In this review, the current trend in microbial lipids as a potential biofuel is discussed.Shimizu, Y., Ateia, M., Yoshimura, C., 2018. Natural organic matter undergoes different molecular sieving by adsorption on activated carbon and carbon nanotubes. Chemosphere 203, 345-352. have comprehensively compared the molecular sieving of natural organic matter (NOM) by adsorption on activated carbon (AC) and multi-walled carbon nanotubes (CNT) using different types of NOM. All water samples were characterized using UV–visible and ?uorescence spectroscopies as well as high-performance size-exclusion chromatography (HPSEC) before and after adsorption. Adsorption isotherm results fitted well with Freundlich model (R2?=?0.95–0.99) and the model parameters indicated higher adsorption of NOM on CNT than AC. Fluorescence index (FI) and freshness index (BIX) showed preferential adsorption of microbial derived and fresh NOM on AC, whereas, terrestrial derived and decomposed NOM were preferentially adsorbed on CNT. Further, HPSEC revealed that AC adsorbed NOM fractions with small molecular weight (MW) (<0.4?kDa) faster than the fractions with higher MW. In contrast, CNT adsorbed NOM fractions characterized by high MW (>1?kDa) while the smallest fraction (<0.4?kDa) was not adsorbed, possibly due to its hydrophilic character. Our results also demonstrated a good correlation between FI and average MW of NOM (R2?>?0.93). These findings illustrate the influence of the adsorbent's type and characteristics (i.e., porosity and pore size distribution) on the preferential adsorption of different NOM fractions.Shin, Y.S., Choi, H.I., Choi, J.W., Lee, J.S., Sung, Y.J., Sim, S.J., 2018. Multilateral approach on enhancing economic viability of lipid production from microalgae: A review. Bioresource Technology 258, 335-344. have been rising as a feedstock for biofuel in response to the energy crisis. Due to a high lipid content, composed of fatty acids favorable for the biodiesel production, microalgae are still being investigated as an alternative to biodiesel. Environmental factors and process conditions can alternate the quality and the quantity of lipid produced by microalgae, which can be critical for the overall production of biodiesel. To maximize both the lipid content and the biomass productivity, it is necessary to start with robust algal strains and optimal physio–chemical properties of the culture environment in combination with a novel culture system. These accumulative approaches for cost reduction can take algal process one step closer in achieving the economic feasibility.Shkolyar, S., Eshelman, E.J., Farmer, J.D., Hamilton, D., Daly, M.G., Youngbull, C., 2018. Detecting kerogen as a biosignature using colocated UV time-gated Raman and fluorescence spectroscopy. Astrobiology 18, 431-453. Mars 2020 mission will analyze samples in situ and identify any that could have preserved biosignatures in ancient habitable environments for later return to Earth. Highest priority targeted samples include aqueously formed sedimentary lithologies. On Earth, such lithologies can contain fossil biosignatures as aromatic carbon (kerogen). In this study, we analyzed nonextracted kerogen in a diverse suite of natural, complex samples using colocated UV excitation (266?nm) time-gated (UV-TG) Raman and laser-induced fluorescence spectroscopies. We interrogated kerogen and its host matrix in samples to (1) explore the capabilities of UV-TG Raman and fluorescence spectroscopies for detecting kerogen in high-priority targets in the search for possible biosignatures on Mars; (2) assess the effectiveness of time gating and UV laser wavelength in reducing fluorescence in Raman spectra; and (3) identify sample-specific issues that could challenge rover-based identifications of kerogen using UV-TG Raman spectroscopy. We found that ungated UV Raman spectroscopy is suited to identify diagnostic kerogen Raman bands without interfering fluorescence and that UV fluorescence spectroscopy is suited to identify kerogen. These results highlight the value of combining colocated Raman and fluorescence spectroscopies, similar to those obtainable by SHERLOC on Mars 2020, to strengthen the confidence of kerogen detection as a potential biosignature in complex natural samples.Siddiqui, M.A.Q., Ali, S., Fei, H., Roshan, H., 2018. Current understanding of shale wettability: A review on contact angle measurements. Earth-Science Reviews 181, 1-11. the success of hydrocarbon production from unconventional shale reservoirs, the understanding of shale wettability under in-situ conditions remains a challenge. Shale wettability reported in the literature has a wide spectrum from water-wet to mixed-wet and oil-wet. This review however shows that the wettabilities of shales are quite consistent when converted to reservoir conditions for hydrocarbon/brine/shale systems. The review reveals that while shale is oil-wet in presence of air when compared to water (oil contact angle is much lower than water contact angle in air) based on contact angle measurements, it is preferentially water-wet when converted to hydrocarbon/brine/shale system using Young equation no matter what composition shale has or what type of oil or brine is used i.e. it is with the caveat that the water is free from surfactants. This is a significant finding that can explain many unexpected wettability observations of shale rocks. What makes the shale wettability more interesting and in some way adds to its complexity is the effect of state variables such as ionic strength, pressure, temperature, pH, clay content, and organic matter content on contact angle. This review further discusses various studies that have up to now attempted to characterize the effect of these state variables on wettability based on contact angle measurements for different shales around the world.Sirois, M., Couturier, M., Barber, A., Gélinas, Y., Chaillou, G., 2018. Interactions between iron and organic carbon in a sandy beach subterranean estuary. Marine Chemistry 202, 86-96. the behavior of terrestrially derived dissolved organic carbon (DOC) through subterranean estuaries (STEs) is essential for determining the carbon budget in coastal waters. However, few studies exist on the interaction of organic carbon (OC) and iron (Fe) in these dynamic systems, where fresh groundwater mixes with recirculated seawater. Here, we focused on the origin and behavior of DOC, and we quantified the relative proportion of OC trapped by reactive Fe-hydroxides along a sandy beach STE. The δ13C-DOC signal in beach groundwater seems to respond rapidly to OC inputs. Our results show a terrestrial imprint from the aquifer matrix dominated by the degradation of particulate organic carbon (POC) issue from an old soil horizon composed of terrestrial plant detritus (14C dating ~800 to 700?years B.P) which is buried below the Holocene sand. Even though the system can be sporadically affected by massive inputs of marine OC, this transient marine imprint seems to be rapidly evacuated from the STE. As reported in soil and in marine mud, Fe–OC trapping occurs in the sandy sediment of the STE. At the groundwater–seawater interface, newly precipitated reactive Fe-hydroxides interact with and trap terrestrial OC independently of the DOC origin in beach groundwater. The molecular fractionation of DOC along the STE and preferential trapping of terrestrial compounds favor the in situ degradation and/or export of non-Fe-stabilized marine-derived molecules to coastal waters. These findings support the idea that the sandy beach STE acts as a transient sink for terrestrial OC at the land–sea interface and contributes to the regulation of marine vs. terrestrial carbon exports to coastal waters.Sivaramakrishnan, R., Incharoensakdi, A., 2018. Microalgae as feedstock for biodiesel production under ultrasound treatment – A review. Bioresource Technology 250, 877-887. application of ultrasound in biodiesel production has recently emerged as a novel technology. Ultrasound treatment enhances the mass transfer characteristics leading to the increased reaction rate with short reaction time and potentially reduces the production cost. In this review, application of ultrasound-assisted biodiesel production using acid, base and enzyme catalysts is presented. A critical assessment of the current status of ultrasound in biodiesel production was discussed with the emphasis on using ultrasound for efficient microalgae biodiesel production. The ultrasound in the biodiesel production enhances the emulsification of immiscible liquid reactant by microturbulence generated by cavitation bubbles. The major benefit of the ultrasound-assisted biodiesel production is a reduction in reaction time. Several different methods have been discussed to improve the biodiesel production. Overall, this review focuses on the current understanding of the application of ultrasound in biodiesel production from microalgae and to provide insights into future developments.Skoblikow, N.E., Zimin, A.A., 2018. Mineral grains, dimples, and hot volcanic organic streams: Dynamic geological backstage of macromolecular evolution. Journal of Molecular Evolution 86, 172-183. hypothesis of hot volcanic organic stream as the most probable and geologically plausible environment for abiogenic polycondensation is proposed. The primary synthesis of organic compounds is considered as result of an explosive volcanic (perhaps, meteorite-induced) eruption. The eruption was accompanied by a shock wave propagating in the primeval atmosphere and resulting in the formation of hot cloud of simple organic compounds—aldehydes, alcohols, amines, amino alcohols, nitriles, and amino acids—products, which are usually obtained under the artificial conditions in the spark-discharge experiments. The subsequent cooling of the organic cloud resulted in a gradual condensation and a serial precipitation of organic compounds (in order of decreasing boiling point values) into the liquid phase forming a hot, viscous and muddy organic stream (named “lithorheos”). That stream—even if the time of its existence was short—is considered here as a geologically plausible environment for abiogenic polycondensation. The substances successively prevailing in such a stream were cyanamide, acetamide, formamide, glycolonitrile, acetonitrile. An important role was played by mineral (especially, phosphate-containing) grains (named “lithosomes”), whose surface was modified with heterocyclic nitrogen compounds synthesized in the course of eruption. When such grains got into hot organic streams, their surface catalytic centers (named “lithozymes”) played a decisive role in the emergence, facilitation and maintenance of prebiotic reactions and key processes characteristic of living systems. Owing to its cascade structure, the stream was a factor underlying the formation of mineral-polymeric aggregates (named “lithocytes”) in the small natural streambed cavities (dimples)—as well as a factor of their further spread within larger geological locations which played a role of chemo-ecological niches. All three main stages of prebiotic evolution (primary organic synthesis, polycondensation, and formation of proto-cellular structures) are combined within a common dynamic geological process. We suppose macromolecular evolution had an extremely fast, “flash” start: the period from volcanic eruption to formation of lithocyte “populations” took not million years but just several tens of minutes. The scenario proposed can be verified experimentally with a three-module setup working with principles of dynamic (flow) chemistry in its core element.Slater, B.J., Harvey, T.H.P., Butterfield, N.J., Rahman, I., 2018. Small carbonaceous fossils (SCFs) from the Terreneuvian (lower Cambrian) of Baltica. Palaeontology 61, 417-439. describe a new assemblage of small carbonaceous fossils (SCFs) from diagenetically minimally altered clays and siltstones of Terreneuvian age from the Lontova and Voosi formations of Estonia, Lithuania and Russia. This is the first detailed account of an SCF assemblage from the Terreneuvian and includes a number of previously undocumented Cambrian organisms. Recognizably bilaterian?derived SCFs include abundant protoconodonts (total?group Chaetognatha), and distinctive cuticular spines of scalidophoran worms. Alongside these metazoan remains are a range of protistan?grade fossils, including Retiranus balticus gen. et sp. nov., a distinctive funnel?shaped or sheet?like problematicum characterized by terminal or marginal vesicles, and Lontohystrichosphaera grandis gen. et sp. nov., a large (100?550??m) ornamented vesicular microfossil. Together these data offer a fundamentally enriched view of Terreneuvian life in the epicratonic seas of Baltica, from an episode where records of non?biomineralized life are currently sparse. Even so, the recovered assemblages contain a lower diversity of metazoans than SCF biotas from younger (Stage 4) Baltic successions that represent broadly equivalent environments, echoing the diversification signal recorded in the coeval shelly and trace?fossil records. Close comparison to the biostratigraphical signal from Fortunian small shelly fossils supports a late Fortunian age for most of the Lontova/Voosi succession, rather than a younger (wholly Stage 2) range.Smith, A., Cooper, A., Misra, S., Bharuth, V., Guastella, L., Botes, R., 2018. The extant shore platform stromatolite (SPS) facies association: a glimpse into the Archean? Biogeosciences 15, 2189-2203. platform stromatolites (SPS) were first noted at Cape Morgan on the south-east African seaboard. Since then they have been found growing discontinuously in rocky peritidal zones along the entire southern African seaboard. They have also been found on the southwest Australian coast, at Giant's Causeway in Northern Ireland, and more recently at Harris on the Scottish Hebridean Atlantic coast. In this paper SPS occurrence and SPS potential as analogues for Precambrian fossil stromatolites, as well as potential stromatolite occurrences in shore platform regions on Mars, are assessed. Sub-horizontal surfaces promote stromatolite development, while tufa develops on cliffs and steep rocky surfaces. Tufa and stromatolites are end members of a spectrum dictated by coastal topography. Extant SPS occur on well indurated shore platforms in high wave energy settings, often around or near headlands. They can be associated with boulder beaches, boulder ridges, storm swash terraces, coastal dunes, and peat bogs. In contrast to other extant stromatolites, SPS are produced primarily by mineral precipitation, although minor trapping and binding stromatolites do occur. From a geological perspective, SPS develop in mildly transgressive siliciclastic settings in various climatic and tidal regimes. We suggest that SPS could be preserved in the geological record as micritic lenses on palaeo-shore platform surfaces. SPS share many features with Precambrian stromatolites and are a valid modern analogue despite the widely different atmospheric and oceanic conditions of the Archean. We suggest that terraces associated with former oceanic or lacustrine flooding surfaces on Mars are potential targets in the search for palaeo-SPS on Mars.Smith, K.C., 2018. Life as adaptive capacity: Bringing new life to an old debate. Biological Theory 13, 76-92. we take “life” to mean, it must involve an attempt to describe the objective reality beyond scientists’ biases. Traditionally, this is thought to involve comparing our scientific categories to “natural kinds.” But this approach has been tainted with an implicit metaphysics, inherited from Aristotle, that does not fit biological reality. In particular, we must accept that biological categories will never be specifiable in terms of necessary and sufficient conditions or shared underlying physical structures that produce clean boundaries. Biology blurs all lines and failure to embrace this unique feature has blocked attempts to reach consensus on the meaning of “life.” Thus, while the three classical accounts (thermodynamic, metabolic, and evolutionary) all fall short of offering a complete definition, their advocates fail to realize that they share the same view of life’s ultimate, functional hallmark: its uniquely rich adaptive capacity. I develop an account of life as adaptive capacity that sidesteps debates about the relative importance of specific mechanisms and the precise location of boundaries to bring the three classical accounts together under a shared conceptual framework.Souffreau, C., Busschaert, P., Denis, C., Van Wichelen, J., Lievens, B., Vyverman, W., De Meester, L., 2018. A comparative hierarchical analysis of bacterioplankton and biofilm metacommunity structure in an interconnected pond system. Environmental Microbiology 20, 1271-1282. is unknown whether bacterioplankton and biofilm communities are structured by the same ecological processes, and whether they influence each other through continuous dispersal (known as mass effects). Using a hierarchical sampling approach we compared the relative importance of ecological processes structuring the dominant fraction (relative abundance ≥0.1%) of bacterioplankton and biofilm communities from three microhabitats (open water, Nuphar and Phragmites sites) at within‐ and among‐pond scale in a set of 14 interconnected shallow ponds. Our results demonstrate that while bacterioplankton and biofilm communities are highly distinct, a similar hierarchy of ecological processes is acting on them. For both community types, most variation in community composition was determined by pond identity and environmental variables, with no effect of space. The highest β‐diversity within each community type was observed among ponds, while microhabitat type (Nuphar, Phragmites, open water) significantly influenced biofilm communities but not bacterioplankton. Mass effects among bacterioplankton and biofilm communities were not detected, as suggested by the absence of within‐site covariation of biofilm and bacterioplankton communities. Both biofilm and plankton communities were thus highly structured by environmental factors (i.e., species sorting), with among‐lake variation being more important than within‐lake variation, whereas dispersal limitation and mass effects were not observed. Souza, L.M., Tose, L.V., Cardoso, F.M.R., Fleming, F.P., Pinto, F.E., Kuster, R.M., Filgueiras, P.R., Vaz, B.G., Rom?o, W., 2018. Evaluating the effect of ion source gas (N2, He, and synthetic air) on the ionization of hydrocarbon, condensed aromatic standards, and paraffin fractions by APCI(+)FT-ICR MS. Fuel 225, 632-645. study aimed to use different types of ion source gases [synthetic air, nitrogen (N2), and helium (He)] to compare the ionization efficiency of linear, branched, and cyclic hydrocarbon (HC) standards (i.e., hexatriacontane, squalene, and 5-α-cholestane, respectively), condensed aromatics (CA) standards (i.e., coronene, benz[a]anthracene, and n,n′-bis(3-pentyl)perylene-3,4,9,10-bis(dicarboximide)), one n-paraffin standard, containing carbon numbers ranging from C5 to C120, and two saturated HC fractions. In all cases, a positive-ion mode atmospheric pressure chemical ionization coupled to a Fourier transform ion cyclotron resonance mass spectrometer was used. Isooctane reagent was used to facilitate the ionization of n-paraffins. Three ionization mechanisms were observed: electron transfer ([M]rad+), proton transfer ([M+H]+), and hydride abstraction ([M?H]+). For the ionization of HC standards, synthetic air and He gases presented better ionization efficiency and produced mass spectra with greater mass accuracy and signal-to-noise rate. Moreover, linear HCs were preferentially ionized through hydride abstraction (production of [M?H]+ ions), whereas the ionization of unsaturated and cyclic HCs mostly occurred through the production of [M+H]+ and [Mrad+] species. The unique exception is related to 5-α-cholestane, which is ionized as [M?H]+ in the presence of synthetic air. For the CA standards, N2 and synthetic air promoted the detection of CA standards mainly by electron transfer mechanism, [M]rad+ species. Conversely, He favored the proton transfer ionization ([M+H]+) with minimal fragmentation or oxidation of the analyte. In all cases, synthetic air provided mass spectra with excellent signal-to-noise ratio. This performance was attributed to the high reactive-ionizing power of O2 gas over the HC and CA molecules. For the n-paraffin samples, synthetic air and He provided better ionization performance through hydride abstraction ([M?H]+). N2 favored the production and ionization of heteroatomic compound classes (Ox and NOx).Specchiulli, A., Cilenti, L., D'Adamo, R., Fabbrocini, A., Guo, W., Huang, L., Lugliè, A., Padedda, B.M., Scirocco, T., Magni, P., 2018. Dissolved organic matter dynamics in Mediterranean lagoons: The relationship between DOC and CDOM. Marine Chemistry 202, 37-48. lagoons are highly vulnerable to climate change-related pressures, such as floods and increasing temperatures, which lead to higher oxygen consumption, anaerobic metabolism and dystrophic events. Although these factors have a significant impact on the carbon cycle, the dynamics of dissolved organic matter (DOM) in these systems have not been extensively investigated. DOM can be analytically determined from the concentration of dissolved organic carbon (DOC) and/or from the spectral properties of chromophoric dissolved organic matter (CDOM), which is the light-absorbing fraction of DOM. In the present study, we investigated the spatio-temporal distribution of surface water trophic variables (Chl a and DOC) and CDOM in two Mediterranean lagoon systems, the Oristano Lagoon-Gulf system (OLG) and the Varano Lagoon (VL), in order to provide quantitative information on the dynamics of DOM in these systems. Furthermore, we assessed the value of CDOM-related indices (i.e. absorption coefficients, spectral slopes and Specific UV Absorbance at 254?nm [SUVA254]) as tools for describing the dynamics of DOM in coastal lagoons, irrespective of geographical settings, environmental conditions and anthropogenic pressures. In OLG, spatial heterogeneity and compartmentalization, with salinity varying from <1 (riverine sites) to >50 (Mistras Lagoon), affected the distribution of DOC and CDOM, with the lowest values on the south side and at sites far from riverine input. In OLG, the highest DOC and CDOM values were found in the sediment pore-water of the organic-rich Cabras Lagoon, where they were nearly double those of the water column. In VL, salinity was homogeneously distributed throughout the lagoon, which indicated a mixing of freshwater with marine waters. DOC and CDOM values were on average lower in VL than in OLG. However, in VL, DOC and CDOM showed strong peaks following a flood (September 2014) and a dystrophic event (July 2015), demonstrating the quick response of the system to environmental perturbation. In OLG, absorption coefficients at 280?nm and 350?nm were slightly negatively correlated with salinity, which indicated the influence of terrigenous inputs at riverine sites. In contrast, in VL, CDOM varied linearly and positively with salinity as a result of the in situ input of organic matter from phytoplankton during the dry season. Segment analysis showed that besides the differences between the two investigated systems, the trophic variables and optical parameters analyzed in the present study shared a common relationship. These results suggest that CDOM indices can be good predictors for the estimation of DOM. Overall, the present study provides insight into the dynamics of DOC and CDOM in little-studied Mediterranean lagoons and demonstrates that the CDOM indices can be a valuable, cost-effective and simple tool for describing the trophic conditions of these systems.Stach, R., Pejcic, B., Heath, C., Myers, M., Mizaikoff, B., 2018. Mid-infrared sensor for hydrocarbon monitoring: the influence of salinity, matrix and aging on hydrocarbon-polymer partitioning. Analytical Methods 10, 1516-1522. sensors (MIR) based on attenuated total reflection (ATR) spectroscopy provide a robust and sensitive platform for the detection of low levels of organic molecules dissolved in water. The chemical and partitioning properties of the polymer membrane play an important role and are crucial to MIR-ATR sensor performance. Although the MIR-ATR sensor has been used to quantify dissolved hydrocarbons in a wide range of aquatic environments, very little is reported on the impact of aqueous solution composition and polymer membrane aging on the hydrocarbon-polymer partitioning process. In the present study we investigated a number of factors that may affect the sensor sensitivity and analytical performance during quantification of hydrocarbons in water. Calibration curves were obtained as a function of salinity and it was revealed that the response factors are generally higher in the presence of salts. We show that reliable hydrocarbon analysis can be achieved in water provided that the sensor is calibrated using appropriate standard solutions and corrected for salinity/ionic strength variations. Sensor measurements were also performed over a range of crude oil-water mixtures, and these studies revealed that the total petroleum hydrocarbon concentration in solution (between the 0 and 20 ppm range) has a negligible effect on the analyte-polymer partitioning process. In terms of sensor durability, the polymer film displayed remarkable repeatability and long-term stability in water over a two-month testing period.Stapel, J.G., Schwamborn, G., Schirrmeister, L., Horsfield, B., Mangelsdorf, K., 2018. Substrate potential of last interglacial to Holocene permafrost organic matter for future microbial greenhouse gas production. Biogeosciences 15, 1969-1985. this study the organic matter (OM) in several permafrost cores from Bol'shoy Lyakhovsky Island in NE Siberia was investigated. In the context of the observed global warming the aim was to evaluate the potential of freeze-locked OM from different depositional ages to act as a substrate provider for microbial production of greenhouse gases from thawing permafrost. To assess this potential, the concentrations of free and bound acetate, which form an appropriate substrate for methanogenesis, were determined. The largest free-acetate (in pore water) and bound-acetate (organic-matrix-linked) substrate pools were present in interstadial marine isotope stage (MIS) 3 and stadial MIS 4 Yedoma permafrost deposits. In contrast, deposits from the last interglacial MIS 5e (Eemian) contained only a small pool of substrates. The Holocene (MIS 1) deposits revealed a significant bound-acetate pool, representing a future substrate potential upon release during OM degradation. Additionally, pyrolysis experiments on the OM allocated an increased aliphatic character to the MIS 3 and 4 Late Pleistocene deposits, which might indicate less decomposed and presumably more easily degradable OM. Biomarkers for past microbial communities, including those for methanogenic archaea, also showed the highest abundance during MIS 3 and 4, which indicated OM-stimulated microbial degradation and presumably greenhouse gas production during time of deposition. On a broader perspective, Arctic warming will increase and deepen permafrost thaw and favor substrate availability from older freeze-locked permafrost deposits. Thus, the Yedoma deposits especially showed a high potential for providing substrates relevant for microbial greenhouse gas production.Storbeck, K.-H., Gilligan, L., Jenkinson, C., Baranowski, E.S., Quanson, J.L., Arlt, W., Taylor, A.E., 2018. The utility of ultra-high performance supercritical fluid chromatography–tandem mass spectrometry (UHPSFC-MS/MS) for clinically relevant steroid analysis. Journal of Chromatography B 1085, 36-41. chromatography tandem mass spectrometry (LC-MS/MS) assays are considered the reference standard for serum steroid hormone analyses, while full urinary steroid profiles are only achievable by gas chromatography (GC–MS). Both LC-MS/MS and GC–MS have well documented strengths and limitations. Recently, commercial ultra-high performance supercritical fluid chromatography–tandem mass spectrometry (UHPSFC-MS/MS) systems have been developed. These systems combine the resolution of GC with the high-throughput capabilities of UHPLC. Uptake of this new technology into research and clinical labs has been slow, possibly due to the perceived increase in complexity. Here we therefore present fundamental principles of UHPSFC-MS/MS and the likely applications for this technology in the clinical research setting, while commenting on potential hurdles based on our experience to date.Su, A., Chen, H., Chen, X., He, C., Liu, H., Li, Q., Wang, C., 2018. The characteristics of low permeability reservoirs, gas origin, generation and charge in the central and western Xihu depression, East China Sea Basin. Journal of Natural Gas Science and Engineering 53, 94-109. from conventional gas in the middle-shallow formation in the Xihu depression in the East China Sea Basin, low permeability gas sandstone layers in the middle-deep formation have recently been discovered. On the basis of integrated analysis of reservoir petrology and diagenesis, geochemistry of gas and source rocks, basin numerical modeling, gold-tube pyrolysis experiment of rocks and fluid inclusion, a comprehensive investigation of the characteristics of low-permeability reservoirs, gas origin, generation and charge in the sub-structural belts (West Slope Belt and West Sub Sag) has been performed. Strong mechanical compaction, filar authigenic illite, siliceous and carbonate cements are key factors for the formation of low permeability reservoirs. The comprehensive analysis of molecular components, stable carbon isotope compositions of gases and light hydrocarbons indicated that the low permeability gases in the WSB are mainly coal-derived and can be divided into two types: (1) mature gases sourced from local coal-measure rocks in the Pinghu Formation, (2) exogenous highly mature gases sourced from the coal-measure rocks in the Pinghu Formation in the WSS. Mature gases were injected into the low permeability reservoirs in the middle-lower Pinghu Formation at approximately 2.8Ma～0Ma. In the meantime, partial highly mature gases generated from source rocks in the WSS also migrated to the WSB. On the whole, the gas charge in the WSB is characterized by dual-sourcing and late-stage. The low permeability gases in the WSS almost are highly mature and composed of most coal-derived gases generated from local coal-measure rocks in the Pinghu Formation and a small amount of oil-derived gases generated from local dark mudstones containing sapropelic-type organic matters in the Pinghu Formation. In addition, mature coal-derived gases generated from source rocks in the lower Huagang Formation are also present but very limited. The charge of highly mature gases in the low permeability reservoirs in the lower Huagang Formation in the WSS occurred at approximately 3.9Ma～0Ma.Suaria, G., Aliani, S., Merlino, S., Abbate, M., 2018. The occurrence of paraffin and other petroleum waxes in the marine environment: A review of the current legislative framework and shipping operational practices. Frontiers in Marine Science 5, 94. doi: 10.3389/fmars.2018.00094. the various materials that make up marine debris, lumps of petroleum waxes such as paraffin and microcrystalline wax, are regularly found on beaches worldwide, although not included in the current definition of marine litter. Ingestion by marine organisms is occasionally documented in the scientific literature and mass beaching events are frequently reported along the European coasts, with obvious detrimental consequences to the local communities that have to manage the clean-up and disposal of this substance. According to Annex II of the MARPOL regulation, petroleum waxes are classified as “high viscosity, solidifying and persistent floating products”, whose discharge at sea of tank-washing residues is strictly regulated, but currently permitted within certain limits. Starting from the description of a large stranding event occurred along the Italian coasts in 2017, we review the existing knowledge and regulatory framework and urge the relevant authorities to address this issue, showing that wax pollution is creating evident damages to the European coastal municipalities. Pending further investigations on the potential hazard that this kind of pollution is posing to marine ecosystems, we suggest a careful and more stringent revision of the policies regulating discharges of these products at sea.Subramanian, P., Pirbadian, S., El-Naggar, M.Y., Jensen, G.J., 2018. Ultrastructure of Shewanella oneidensis MR-1 nanowires revealed by electron cryotomography. Proceedings of the National Academy of Sciences 115, E3246-E3255.: Recent findings from in vivo fluorescence and immunolabeling measurements hinted at the possible role of outer membrane (OM) extensions as Shewanella oneidensis MR-1 nanowires. However, a detailed understanding of the architecture and electron transport mechanism along OM extensions was lacking. In this work, we report a unique setup for correlative light and electron microscopy of Shewanella OM extensions and demonstrate that they are chains of interconnected outer membrane vesicles with densities, consistent with periplasmic and OM cytochromes, distributed along their length. We propose, based on the packing density of cytochromes measured from electron cryotomograms, that the electron transport mechanism involves a combination of direct electron hopping and diffusion of electron carriers.Abstract: Bacterial nanowires have garnered recent interest as a proposed extracellular electron transfer (EET) pathway that links the bacterial electron transport chain to solid-phase electron acceptors away from the cell. Recent studies showed that Shewanella oneidensis MR-1 produces outer membrane (OM) and periplasmic extensions that contain EET components and hinted at their possible role as bacterial nanowires. However, their fine structure and distribution of cytochrome electron carriers under native conditions remained unclear, making it difficult to evaluate the potential electron transport (ET) mechanism along OM extensions. Here, we report high-resolution images of S. oneidensis OM extensions, using electron cryotomography (ECT). We developed a robust method for fluorescence light microscopy imaging of OM extension growth on electron microscopy grids and used correlative light and electron microscopy to identify and image the same structures by ECT. Our results reveal that S. oneidensis OM extensions are dynamic chains of interconnected outer membrane vesicles (OMVs) with variable dimensions, curvature, and extent of tubulation. Junction densities that potentially stabilize OMV chains are seen between neighboring vesicles in cryotomograms. By comparing wild type and a cytochrome gene deletion mutant, our ECT results provide the likely positions and packing of periplasmic and outer membrane proteins consistent with cytochromes. Based on the observed cytochrome packing density, we propose a plausible ET path along the OM extensions involving a combination of direct hopping and cytochrome diffusion. A mean-field calculation, informed by the observed ECT cytochrome density, supports this proposal by revealing ET rates on par with a fully packed cytochrome network.Subramanian, S., Buscetti, L., Simon, S., Sacré, M., Sj?blom, J., 2018. Influence of fatty-alkylamine amphiphile on the asphaltene adsorption/deposition at the solid/liquid interface under precipitating conditions. Energy & Fuels 32, 4772-4782. ability of a fatty-alkylamine amphiphile to inhibit asphaltene adsorption/deposition, as well as its ability to disperse the asphaltene layers on stainless steel, was studied using a quartz crystal microbalance with dissipation (QCM-D). The experiments were performed both under good solvent conditions and above asphaltene precipitation onset. The adsorption/deposition of asphaltenes from model oil solution in xylene/n-hexane was found to strongly increase up to the asphaltene precipitation onset (i.e., ～60–65 vol?% n-hexane), with a 7–8 times increase of the adsorbed amount, compared with adsorption from xylene. Beyond the precipitation onset, the amount of asphaltene adsorbed/deposited decreases. Under both good solvent and precipitating conditions, the amphiphile was unable to form a protective layer on stainless steel to prevent asphaltene adsorption/deposition. However, the amphiphile exhibited an excellent ability to reduce asphaltene adsorption/deposition by 80–95 wt?% when injected along with asphaltene solution. It is found that the interactions between asphaltenes and inhibitor that are responsible for the adsorption/deposition inhibitory action are not of an acid–base nature. Maximum inhibitory action in minimizing the asphaltene adsorption/deposition was observed corresponding to a molar ratio (amphiphile/asphaltenes) of ～0.10, despite this molar ratio being insufficient to prevent asphaltene precipitation. Similarly, the amphiphile also displayed an ability to remove 90–95 wt?% of asphaltenes already adsorbed/deposited on stainless steel under precipitating conditions, thereby showing its effectiveness as both an asphaltene inhibitor (AI) and an asphaltene dispersant (AD) under good solvent conditions, as well as precipitating conditions.Sun, B., Wang, J., Wang, Z., Gao, Y., Xu, J., 2018. Calculation of proppant-carrying flow in supercritical carbon dioxide fracturing fluid. Journal of Petroleum Science and Engineering 166, 420-432. a new clear and efficient fracturing fluid, supercritical carbon dioxide (SC-CO2) has many advantages in the development of unconventional oil and gas resources, such as no harm to the reservoir, improving the reservoir permeability and fluid flow resistance, quickly completely flowing back after fracturing. Based on the principle of suspension energy balance, an equilibrium flow rate model of proppant-carrying flow of SC-CO2 is derived, and calculation errors are 3.32% and 4.54%, respectively, compared with equilibrium flow rates obtained from experiments under different density and particle sizes. By considering the change of fluid internal energy and flow work, filtration characteristics, physical parameters, and SC-CO2–rock adsorption in the SC-CO2 fracturing process, a proppant-carrying flow calculation model of the SC-CO2 fracturing fluid is established based on temperature–pressure field coupling, fracture and filtration zone coupling, and SC-CO2 fluid and proppant coupling. In the experiment, the heights of nine groups of proppant embankments were measured, and the average model prediction error value is 3.43%. SC-CO2 has a similar proppant-carrying capacity to that of clear water under the high Reynolds number condition. Based on the proppant-embankment prediction model of SC-CO2 fracturing, through analyzing proppant-carrying characteristics of the SC-CO2 fracturing fluid, the proppant concentration distribution and proppant embankment section are obtained at different fracturing times. According to the calculation, as the fracturing fluid pumping rate increases, proppant density and proppant particle size will decrease, the viscosity of the SC-CO2 fracturing fluid system will increase, and proppant accumulation height can be reduced over a small range, while proppant accumulation length will experience a greater increase along the fracture length direction. During field operation of SC-CO2 fracturing, the proppant pumping process should be optimized according to the proppant embankment section and proppant concentration should be choose increased in small steps to meet fracture propping requirements.Sun, H., Xiao, Y., Gao, Y., Zhang, G., Casey, J.F., Shen, Y., 2018. Rapid enhancement of chemical weathering recorded by extremely light seawater lithium isotopes at the Permian–Triassic boundary. Proceedings of the National Academy of Sciences 115, 3782-3787.: Estimates of seawater Li isotopic composition at the Permian–Triassic boundary (PTB) reveal extremely light seawater Li isotopic signatures accompanying the most severe mass extinction in the history of animal life. Theoretical modeling indicates a rapid enhancement of continental weathering during this time, which was likely triggered by the eruption of the Siberian Traps, rapid global warming, and acid rains. Our results provide independent geochemical evidence for an enhanced continental chemical weathering at the PTB, illustrating that continental weathering may provide a key link between terrestrial and marine ecological crises.Abstract: Lithium (Li) isotope analyses of sedimentary rocks from the Meishan section in South China reveal extremely light seawater Li isotopic signatures at the Permian–Triassic boundary (PTB), which coincide with the most severe mass extinction in the history of animal life. Using a dynamic seawater lithium box model, we show that the light seawater Li isotopic signatures can be best explained by a significant influx of riverine [Li] with light δ7Li to the ocean realm. The seawater Li isotope excursion started ≥300 Ky before and persisted up to the main extinction event, which is consistent with the eruption time of the Siberian Traps. The eruption of the Siberian Traps exposed an enormous amount of fresh basalt and triggered CO2 release, rapid global warming, and acid rains, which in turn led to a rapid enhancement of continental weathering. The enhanced continental weathering delivered excessive nutrients to the oceans that could lead to marine eutrophication, anoxia, acidification, and ecological perturbation, ultimately resulting in the end-Permian mass extinction.Sun, M.S., Zhang, G.L., Ma, X., Cao, X.P., Mao, X.Y., Li, J., Ye, W.W., Liu, S.M., 2018. Dissolved methane in the East China Sea: Distribution, seasonal variation and emission. Marine Chemistry 202, 12-26. present a dataset of dissolved methane (CH4) in the East China Sea (ECS) during five cruises in March, May, August, October and December 2011. CH4 distribution in this region showed pronounced spatial and seasonal variability due to the complex mixing of different water masses and other variables. Surface CH4 concentrations gradually decreased from the coast to the open sea, with maximum values occurring near Changjiang estuary or outside the Hangzhou Bay. The annual mean CH4 concentration of the surface layer was 9.1?±?1.6?nmol?L?1 in the coastal area, which was nearly twice as large as that in the open sea (4.3?±?1.3?nmol?L?1). CH4 was distributed evenly from the surface to the bottom in the shelf region during March and December, while it increased gradually with depth during May and October. CH4 depth profiles exhibited various distribution features along the coast, in the middle and on the edge of continental shelf. CH4 levels at the bottom were generally higher than at the surface during all seasons, indicating obvious CH4 sources from sediments. Incubation experiments of sediment cores onboard suggested that sediment release was an important source of CH4 in the water column of the ECS. We estimated that the annual average CH4 release rate from sediments was about 1.11?μmol·m?2·d?1 on the continental shelf of the ECS. The maximum CH4 concentration and sediment-water CH4 flux both occurred in summer, which might be related with the occurrence of hypoxia in the bottom water. Surface seawater of the ECS was oversaturated with CH4 relative to the atmosphere over most of the five cruises, indicating that the ECS was a net source of atmospheric CH4. The annual mean area-weighted sea-air flux density of CH4 in the ECS was estimated to be about 10.7?μmol·m?2·d?1 in 2011. Accordingly, an area-weighted, seasonally adjusted annual rate of CH4 efflux was determined to be 2.98?×?109?mol?yr?1 (~0.05?Tg CH4 yr?1) from the ECS to the atmosphere.Sun, W., Zhang, E., Liu, E., Chang, J., Chen, R., Shen, J., 2018. Glacial-interglacial vegetation changes in northeast China inferred from isotopic composition of pyrogenic carbon from Lake Xingkai sediments. Organic Geochemistry 121, 80-88. the changes in monsoon intensity and ecosystem response at different timescales is crucial for the well-being of humans, yet the paleoclimatic interpretation of stable carbon isotope (δ13C) values from northeast China records is debatable. In this study, reported δ13C data from 76 surface soils in northeast China are compiled, and a δ13C record of pyrogenic carbon (δ13CPyC) from Lake Xingkai in northeast China since the last interglacial period is presented. The aim was to investigate the orbital timescale environmental implication of geological δ13CPyC data for northeast China. The results showed a distinct increase in δ13C values of surface soils, which correlated with increasing temperature of the warmest month. Higher temperature favored the expansion of C4 plants, while precipitation had only a weak correlation with δ13C values of surface soils in the region. On an orbital timescale, the δ13CPyC record from Lake Xingkai generally reflected paleovegetation change, suggesting that the abundance of C4 plants was relatively high during the warm periods, changing to almost purely C3 plants during the cold periods. Both modern and geological analysis suggest that the climatic factor determining the δ13C in northeast China was temperature of the warmest month. This is similar to the situation for mid-latitudes such as the Chinese Loess Plateau, in contrast to low latitudes such as southern China.Sun, X.-M., Geng, L.-J., Ren, L.-J., Ji, X.-J., Hao, N., Chen, K.-Q., Huang, H., 2018. Influence of oxygen on the biosynthesis of polyunsaturated fatty acids in microalgae. Bioresource Technology 250, 868-876. one of the most important environmental factors, oxygen is particularly important for synthesis of n-3 polyunsaturated fatty acids (n-3 PUFA) in microalgae. In general, a higher oxygen supply is beneficial for cell growth but obstructs PUFA synthesis. The generation of reactive oxygen species (ROS) under aerobic conditions, which leads to the peroxidation of lipids and especially PUFA, is an inevitable aspect of life, but is often ignored in fermentation processes. Irritability, microalgal cells are able to activate a number of anti-oxidative defenses, and the lipid profile of many species is reported to be altered under oxidative stress. In this review, the effects of oxygen on the PUFA synthesis, sources of oxidative damage, and anti-oxidative defense systems of microalgae were summarized and discussed. Moreover, this review summarizes the published reports on microalgal biotechnology involving direct/indirect oxygen regulation and new bioreactor designs that enable the improved production of PUFA.Sun, Y., Zhao, Y., Yuan, L., 2018. CO2-ECBM in coal nanostructure: Modelling and simulation. Journal of Natural Gas Science and Engineering 54, 202-215. is a porous media, and most pores in coal are nanopores (pores at the nanoscale). In order to investigate CO2-ECBM based on the nanostructure obtained by synchrotron radiation nano-CT at the Beijing Synchrotron Radiation Facility (BSRF), a nanopore structure-based CO2-ECBM model was developed, in which extended Langmuir Equation was applied to formulate the competitive adsorption mechanism of binary gas system of CO2-CH4 and gas ad/de-sorption and diffusion were coupled. CH4 and CO2 distribution in the coal nanostructure during the CO2-ECBM was visualized and the effect of CO2 injection pressure on methane recovery and CO2 sequestration was investigated. The increase of CO2 injection pressure enhances methane recovery and CO2 injection, but the contribution of CO2 injection pressure on methane recovery rate and CO2 injection rate becomes weaker with the increase of CO2 injection pressure. Because prior researches have shown that gas diffusivity varies with gas pressure, the impact of CO2 diffusion coefficient which varies with CO2 injection pressure on methane recovery and CO2 injection was investigated, and results show the variation of CO2 diffusion coefficient caused by the variation of CO2 injection pressure can explain why the increase of CO2 injection pressure can enhance CH4 recovery and CO2 injection. The difference in CO2 injection rate and CH4 recovery rate between different coal samples is related to the difference in gas diffusivity in different coal samples. CO2 injection rate and CH4 recovery rate is relatively higher in coal with higher gas diffusivity. The higher diffusion coefficient of CO2 caused by the lower kinetic diameter of CO2 can also help to explain why CO2 injection rate is larger than CH4 recovery rate. This study provides a new option to explore the CO2-ECBM at the nanopore scale.Svensen, H.H., Iyer, K., Schmid, D.W., Mazzini, A., 2018. Modelling of gas generation following emplacement of an igneous sill below Lusi, East Java, Indonesia. Marine and Petroleum Geology 90, 201-208. Lusi mud eruption started in 2006 and is located near the Arjuno-Welirang volcanic complex in Northeastern Java. Lusi is characterized by the eruption of aqueous vapor, CO2, and CH4 in addition to mud breccia and boiling water. However, the ultimate driving force for the eruption remains unclear. Here we investigate if Lusi could have been driven by the heat released from a deep-seated igneous sill originating from the neighboring volcanic arc. We have used a 1D thermal model to calculate the production of CO2 from thermally matured organic matter in the contact aureole of a hypothetical 150 m thick sill. The sill is tentatively emplaced at 1100 °C at 4.5 km depth within the organic-rich Eocene Ngimbang Formation. The carbon gas produced from the thermal perturbation reaches a peak of 1357 kg/m2/y CO2 equivalents shortly after sill emplacement, stressing the efficiency of organic matter transformation in contact aureoles. Our simulations show that during the first 1000 years after emplacement, 53.5 ton CO2/m2 is produced in the contact aureole. When scaled to a sill size of 150 m × 25 km2, i.e., a sill volume of 3.75 km3, the aureole has the potential to generate a total of 1350 Mt CO2 during the first 1000 years, with a peak generation of about 34 Mt CO2/y. We conclude that contact metamorphism in our hypothetical geological scenario generates CO2 in the gigaton range and represents a plausible source for the Lusi gas.Sweere, T.C., Dickson, A.J., Jenkyns, H.C., Porcelli, D., Elrick, M., van den Boorn, S.H.J.M., Henderson, G.M., 2018. Isotopic evidence for changes in the zinc cycle during Oceanic Anoxic Event 2 (Late Cretaceous). Geology 46, 463-466. deposition of organic-rich shales during the Late Cretaceous Oceanic Anoxic Event 2 (OAE 2, ca. 94 Ma) occurred during a period of significant global paleo-environmental and geochemical change. It has been proposed that an increase in nutrient input to the ocean during OAE 2 was the key mechanism that generated and sustained high rates of organic-matter burial over time scales of 103–105 yr. Zinc is a bio-essential micronutrient and the proportion of Zn burial in oxic sediments relative to burial in organic-rich continental margin sediments is reflected in its seawater isotope composition. The first Zn-isotope records dating from the Cretaceous are presented here from three coeval carbonate successions: two from Europe (southern England and southern Italy) and one from southern Mexico. The new data show reproducible stratigraphic Zn-isotope patterns in spatially and lithologically diverse carbonate successions. Excursions to lower Zn-isotope values may be linked to the input of magmatic Zn, changes in the proportion of Zn burial into organic-rich sediments, and the liberation of previously buried Zn during an episode of widespread seafloor re-oxygenation during OAE 2 (the Plenus Cold Event).S?korová, I., K?íbek, B., Havelcová, M., Machovi?, V., Laufek, F., Veselovsk?, F., ?paldoňová, A., Lap?ák, L., Knésl, I., Matysová, P., Majer, V., 2018. Hydrocarbon condensates and argillites in the Eli?ka Mine burnt coal waste heap of the ?aclé? coal district (Czech Republic): Products of high- and low-temperature stages of self-ignition. International Journal of Coal Geology 190, 146-165. Eli?ka Mine waste coal heap burned intensely in the 1960s and 1980s, and even now, on the surface of the heap, active vents still occur from which warm air (temperature 25–35°C) and water vapor escape. In the neighborhood of active vents, the surficial part of the heap is enriched in hydrocarbon condensates (HCC). Based on differences in optical reflectance and fluorescence color, two types of HCC were identified: The A-type HCC with yellow fluorescence and very low reflectance (~0.30%), which occurs as a binding material or filler of cracks in inorganic and organic particles, and the B-type HCC without fluorescence and with higher reflectance (1.04 to 1.08%). These HCC are probably formed through condensation of organic pyrolysates on the heap surface in various stages of burning, and the two types of HCC most probably reflect a gradual decrease in burning temperature and progressive cooling of the heap surface. This assumption is supported by the chemical composition of HCC extracts, revealing volatile compounds that have formed at various temperatures. Changes in the distribution of n-alkanes, O-, N-, and S-containing compounds also occurred in the chemical fingerprint. The zone enriched in condensates of semivolatile hydrocarbons was also enriched in Hg and S relative to the burnt heap substrate. The underlying argilite zone consisted of a mixture of clay minerals (illite, kaolinite and smectite), jarosite, alunite, and amorphous SiO2, together with mullite, cristobalite, trydimite, and sanidine. This mineral association indicates that argillitization affected the burnt heap substrate (the clinker), which forms a footwall of HCC-enriched and argilite zones. The origin of argilites is thought to be due to the exposure of clinker to water vapor containing high concentrations of H2SO4 and H2S at a late stage of burning. The leaching yields of potentially harmful elements (PHEs) present in the waste samples was determined using batch and percolation tests. The concentrations of Hg, Pb, and Cd in some leachates exceeded the limit values for inert wastes according to EU legislation. However, the concentration of other PHEs was low, probably due to prolonged washout of burnt materials by rainwater at a very low pH (1.5 to 4.6).Symonds, R.T., Hughes, R.W., Lu, D.Y., Navarri, P., Ashrafi, O., 2018. Systems analysis of pressurized chemical looping combustion for SAGD applications. International Journal of Greenhouse Gas Control 73, 111-123. looping combustion is a promising option for the conversion of fossil fuels with inherent separation of CO2 and efficient use of energy. Nevertheless, key process challenges such as oxygen carrier reaction rates, costs, and environmental concerns still exist. We expected that these challenges would be overcome by operating chemical looping combustors at elevated pressures with ilmenite ore as the oxygen carrier. This work describes a design study that was performed to examine the potential for replacement of once-through steam generators (OTSGs) at steam assisted gravity drainage (SAGD) facilities for bitumen production with near zero CO2 emission pressurized chemical looping combustors. In order to minimize capital costs for the systems, design was constrained to ensure that all major components could be shop built. Heat and material balances for many different process configurations were generated using Aspen HYSYS process simulation software allowing for a range of options to be evaluated. We determined that operating pressures should be restricted to between 4 and 7?bar(g) to achieve very high steam generation efficiencies, while avoiding high power demand. Energy integration of pressurized chemical looping combustion with a Canada’s Oil Sands Innovation Alliance (COSIA) typical SAGD plant using Pinch analysis was performed resulting in a significant decrease in natural gas and boiler feed water (BFW) make-up requirements, while at the same time reducing CO2 emissions by over 95% down to 2.85?kg CO2/bbl bitumen. Having established that process performance is attractive, an economic study to establish the most economical design for pressurized chemical looping combustion for steam generation is now required.Száz, D., Horváth, G., 2018. Success of sky-polarimetric Viking navigation: revealing the chance Viking sailors could reach Greenland from Norway. Royal Society Open Science 5, 172187; DOI: 10.1098/rsos.172187. to a famous hypothesis, Viking sailors could navigate along the latitude between Norway and Greenland by means of sky polarization in cloudy weather using a sun compass and sunstone crystals. Using data measured in earlier atmospheric optical and psychophysical experiments, here we determine the success rate of this sky-polarimetric Viking navigation. Simulating 1000 voyages between Norway and Greenland with varying cloudiness at summer solstice and spring equinox, we revealed the chance with which Viking sailors could reach Greenland under the varying weather conditions of a 3-week-long journey as a function of the navigation periodicity Δt if they analysed sky polarization with calcite, cordierite or tourmaline sunstones. Examples of voyage routes are also presented. Our results show that the sky-polarimetric navigation is surprisingly successful on both days of the spring equinox and summer solstice even under cloudy conditions if the navigator determined the north direction periodically at least once in every 3?h, independently of the type of sunstone used for the analysis of sky polarization. This explains why the Vikings could rule the Atlantic Ocean for 300 years and could reach North America without a magnetic compass. Our findings suggest that it is not only the navigation periodicity in itself that is important for higher navigation success rates, but also the distribution of times when the navigation procedure carried out is as symmetrical as possible with respect to the time point of real noon.Tahoun, S.S., Deaf, A.S., Gentzis, T., Carvajal-Ortiz, H., 2018. Modified RGB-based kerogen maturation index (KMI): Correlation and calibration with classical thermal maturity indices. International Journal of Coal Geology 190, 70-83. cutting samples from the Lower Jurassic to the Upper Cretaceous succession of the Abu Tunis-1X well, north Western Desert of Egypt, were processed palynologically to extract their psilate sporomorphs. This designated practice was made to assess the digitally-quantified progressive changes in the triple Red-Green-Blue (RGB) coloration of sporomorph exine with depth. Stabilization and calibration of the illumination system was applied. Certain precautions were also implemented prior to such digital RGB measurements; for example, some exceptionally lighter (caved) or darker (reworked) specimens were excluded from RGB coloration population samples to avoid misleading results. A minimum of three and up to ten spore grains were studied according to the sample richness and two RGB readings were taken for each selected specimen. The average, standard deviation, and confidence level values for each sample were calculated due to the variable palynological productivity of the samples. In the present study, an attempt was made to monitor and distinguish which of the color components and/or parameters is the most sensitive detector of the progressive maturation changes with depth. By investigating the trends of different parameters of the RGB (i.e. total RGB, R, G, B, R/G) with depth, we were able to distinguish and deduce a linear maturation index from the triple RGB readings. Such a linear maturation index was based on the R component and was successfully correlated and calibrated with other conventional, linear maturity indices (Tmax°C, vitrinite reflectance-VRo%, and thermal alteration index-TAI). The newly modified, RGB-based maturation index called the Kerogen Maturity Index (KMI) can confidently and effectively detect the subtle and progressive changes in kerogen maturation with depth. Such correlation and calibration practices presented herein enabled us to present a modern, reliable, easy to use, and inexpensive measuring technique to assess the thermal maturity of organic matter. The KMI covers the immature and most of the mature phases (early-upper mature) of kerogen and it has its own vitrinite-calibrated cut-offs, which can be correlated with both the Tmax and TAI parameters. This undoubtedly allows the KMI to be easily correlated and complement other classical, expensive maturity indices. This opens the door widely for the palynologists and organic petrologists to use the KMI with good confidence and high reliability for its proven good maturity appraisal.Tang, X., Zhang, J., Liu, Y., Yang, C., Chen, Q., Dang, W., Zhao, P., 2018. Geochemistry of organic matter and elements of black shale during weathering in Northern Guizhou, Southwestern China: Their mobilization and inter-connection. Chemie der Erde 78, 140-151. from previous studies on effect of weathering upon geochemical variation along a single weathered profile, this paper provides a new methodology validated by comparing a weathered outcrop samples and their stratigraphic counterpart un-weathered core samples in a nearby shallow borehole. This outcrop and borehole penetrated the Ordovician-Silurian Wufeng–Longmaxi shales, located in the same anticline structure in the northern part of Guizhou Province, Southern China. The mineral composition, major, trace and rare earth elements (REEs) composition and Rock-Eval parameters of outcrop and core samples were analyzed and compared. Organic matter (OM) was observed in the microscope and extracted for elements analysis. The results show that short-term weathering still has significant influence on OM, mineral and elemental composition of black shales. The elements composition shows the outcrop profile was moderately weathered. The REEs compositions do not alter much during weathering process and the REEs composition and their relative ratios still are valid for rock origin determination. The OM, mainly composed by graptolite and bitumen, even entering the highly-over thermal maturity, is still sensitive to the weathering with a systematic loss 30–50% of TOC along the outcrop profile, which suggests that the OM consumption is predominantly controlled by weathering duration and the distance from the weathering surface. In turn, OM has significant influence on the trace elements transportation behavior during weathering. Some trace elements associated with the OM such as V, Cr, Th, U, Ni and Co, change significantly in their absolute concentration during weathering, but their relative ratios do not necessarily change too much and might be still reliable proxies for paleo-environmental determination. The mobility of shale minerals during weathering is in the following order: plagioclase?>?potassium feldspar and dolomite >pyrite and OM. Short-term weathering can also result in considerable transportation of elements and significant variation of minerals content in black shale, which may pose potentially high environmental and engineering risk in the regions rich in black shale.Tao, R., Olivera-Irazabal, M., Yu, K., 2018. Effect of temperature and dispersant (COREXIT? EC 9500A) on aerobic biodegradation of benzene in a coastal salt marsh sediment. Chemosphere 204, 22-27. coastal ecosystem in the northern Gulf of Mexico (GoM) has been seriously impacted by the 2010 BP oil spill. Two experiments were conducted to study the effect of temperature and addition of the dispersant on biodegradation of benzene, as a representative of petroleum hydrocarbon, in a coastal salt marsh sediment under aerobic conditions. The results show that benzene biodegradation was approximately 6 time faster under aerobic conditions (Eh > +300 mV) than under anaerobic iron-reduction conditions (+14 mV < Eh < +162 mV). Benzene biodegradation in response to temperature was in an order of 20 °C > 10 °C > 30 °C as expected in a saline environment. Application of the dispersant caused initial fluctuations of benzene vapor pressure during the incubation due to its hydrophobic and hydrophilic nature of the molecules. Presence of the dispersant shows an inhibitory effect on benzene biodegradation, and the inhibition increased with concentration of the dispersant. The Gulf coast sediment seems in a favorable scenario to recover from the BP oil spill with an average temperature around 20 °C in spring and fall season. Application of the dispersant may be necessary for the oil spill rescue operation, but its side effects may deserve further investigations.Teixeira, C.A.S., Sawakuchi, A.O., Bello, R.M.S., Nomura, S.F., Bertassoli, D.J., Chamani, M.A.C., 2018. Fluid inclusions in calcite filled opening fractures of the Serra Alta Formation reveal paleotemperatures and composition of diagenetic fluids percolating Permian shales of the Paraná Basin. Journal of South American Earth Sciences 84, 242-254. thermal and diagenetic evolution of shale units has received renewed focus because of their emergence as unconventional hydrocarbon reservoirs. The Serra Alta Formation (SAF) is a Permian shale unit of the Paraná Basin, which is the largest South American cratonic basin. The SAF stands out as a pathway for aqueous fluids and hydrocarbon migration from the Irati organic-rich shales to the Pirambóia fluvial-eolian sandstone reservoirs. Vertical NNW and NNE opening fractures would be the main pathways for the migration of buried pore waters and aqueous fluids, besides the input of meteoric water. These fractures would be associated to the reactivation of basement discontinuities such as the Jacutinga (NE) and Guapiara (NW) faults. Thus, vertical NNE and NNW associated fractures would represent the main pathways for fluid migration in the studied area. The vertical calcite filled opening fractures from SAF record moderately low salinity (0–4.5?wt % of NaCl eq.) aqueous fluids, suggesting the input of meteoric water in the buried fracture system. Eutectic melting temperatures at ?52±5?°C indicate an H2O?+?NaCl?+?CaCl2 system with CaCl2 or MgCl2 in solution. Homogenization temperatures recorded in fluid inclusion assemblages (FIAs) of calcite filled opening fractures indicate that the SAF in the studied area reached temperatures above 200?°C, suitable for generation of gaseous hydrocarbons. The recorded paleotemperatures point to a thermal peak associated with Serra Geral volcanic event during the Early Cretaceous, with the thermal effect of volcanic rock cap possibly overcoming the effect of intrusive igneous bodies. The detection of methane in SAF shale pores indicates conditions for hydrocarbon generation. However, additionally studies are necessary to confirm the thermogenic and/or biogenic origin of the methane within the SAF.Tempère, S., Marchal, A., Barbe, J.-C., Bely, M., Masneuf-Pomarede, I., Marullo, P., Albertin, W., 2018. The complexity of wine: clarifying the role of microorganisms. Applied Microbiology and Biotechnology 102, 3995-4007. concept of wine complexity has gained considerable interest in recent years, both for wine consumers and wine scientists. As a consequence, some research programs concentrate on the factors that could improve the perceived complexity of a wine. Notably, the possible influence of microbiological factors is particularly investigated. However, wine complexity is a multicomponent concept not easily defined. In this review, we first describe the actual knowledge regarding wine complexity, its perception, and wine chemical composition. In particular, we emphasize that, contrary to expectations, the perception of wine complexity is not related to wine chemical complexity. Then, we review the impact of wine microorganisms on wine complexity, with a specific focus on publications including sensory analyses. While microorganisms definitively can impact wine complexity, the underlying mechanisms and molecules are far from being deciphered. Finally, we discuss some prospective research fields that will help improving our understanding of wine complexity, including perceptive interactions, microbial interactions, and other challenging phenomena.Thiel, V., Hoppert, M., 2018. Fatty acids and other biomarkers in two Early Jurassic concretions and their immediate host rocks (Lias δ, Buttenheim clay pit, Bavaria, Germany). Organic Geochemistry 120, 42-55. carbonate- and phosphate-rich concretions from Early Jurassic strata at Buttenheim (Bavaria, Germany) and their immediate claystone host rocks were analysed to study the mechanisms of biomarker preservation in concretions. Superimposed on a common sedimentary background signal, distinctive biomarkers reflect microbial processes involved in concretion formation. When normalized to the HCl-insoluble insoluble rock portion, concretions show ～1.5–3 times higher TOC values than their host rocks, but identical absolute quantities of most extractable hydrocarbons. In contrast, n-fatty acids and α,ω-dicarboxylic acids are, by an order, more abundant compared to the host rocks, suggesting an enhanced preservation or selective accumulation mechanism for carboxylic acids in the concretions. Further, linear and iso-/anteiso-fatty acids with unusually short carbon chains (as low as C8) are exclusively observed in the concretions and are interpreted as biodegradation products of lipids derived from in-situ bacteria. Likewise, strongly enhanced neohop-13(18)-enes and hopanoic acids with more ‘immature’ isomer distributions indicate an in-situ contribution of microbial biomass during formation of the concretions. Pyrolysis released ample additional saturated short-chain n-fatty acids from the kerogens of the concretions, but not from the host rocks. We hypothesize that these compounds are remnants of locally accumulated OM rich in fatty acyl moieties (e.g. plant polymers or triglyceride storage lipids) whose hydrolysis products were initially precipitated as fatty acid salts (‘adipocere’). During shallow burial, these substances may have delivered a steadily flowing energy source for sedimentary microorganisms, with their anaerobic decomposition supplying both carbonate and metal ions. In concert with other factors, this may have promoted carbonate precipitation and thus, the formation of the Buttenheim concretions.Thomas, C., Dehaeck, S., De Wit, A., 2018. Convective dissolution of CO2 in water and salt solutions. International Journal of Greenhouse Gas Control 72, 105-116. of CO2 into saline aquifers can lead to the development of buoyancy-driven convection in the brine which enhances the efficiency of CO2 transfer. We analyze here experimentally the onset, development and dynamic properties of such convective fingering of CO2 into water, Antarctic water and in NaCl salt solutions of various concentrations to study the influence of varying the salt concentration on the buoyancy-driven convective dynamics. The convective dissolution pattern is visualized with the help of a schlieren imaging system sensitive to density gradients in the solution. We quantify the growth of convective fingers by performing, among others, a Fourier analysis of the pattern formation at early times and qualitatively study the nonlinear spatio-temporal dynamics at later times. In agreement with theoretical predictions, we find that increasing the salt concentration hinders the development of the instability as it delays the onset of convection, increases the wavelength of the convective pattern, decreases the growth rate and velocity of fingers as well as their interactions. Our experimental results provide quantitative data that should help the benchmarking of theoretical studies.Thornalley, D.J.R., Oppo, D.W., Ortega, P., Robson, J.I., Brierley, C.M., Davis, R., Hall, I.R., Moffa-Sanchez, P., Rose, N.L., Spooner, P.T., Yashayaev, I., Keigwin, L.D., 2018. Anomalously weak Labrador Sea convection and Atlantic overturning during the past 150 years. Nature 556, 227-230. Atlantic meridional overturning circulation (AMOC) is a system of ocean currents that has an essential role in Earth’s climate, redistributing heat and influencing the carbon cycle. The AMOC has been shown to be weakening in recent years; this decline may reflect decadal-scale variability in convection in the Labrador Sea, but short observational datasets preclude a longer-term perspective on the modern state and variability of Labrador Sea convection and the AMOC. Here we provide several lines of palaeo-oceanographic evidence that Labrador Sea deep convection and the AMOC have been anomalously weak over the past 150 years or so (since the end of the Little Ice Age, LIA, approximately ad 1850) compared with the preceding 1,500 years. Our palaeoclimate reconstructions indicate that the transition occurred either as a predominantly abrupt shift towards the end of the LIA, or as a more gradual, continued decline over the past 150 years; this ambiguity probably arises from non-AMOC influences on the various proxies or from the different sensitivities of these proxies to individual components of the AMOC. We suggest that enhanced freshwater fluxes from the Arctic and Nordic seas towards the end of the LIA—sourced from melting glaciers and thickened sea ice that developed earlier in the LIA—weakened Labrador Sea convection and the AMOC. The lack of a subsequent recovery may have resulted from hysteresis or from twentieth-century melting of the Greenland Ice Sheet. Our results suggest that recent decadal variability in Labrador Sea convection and the AMOC has occurred during an atypical, weak background state. Future work should aim to constrain the roles of internal climate variability and early anthropogenic forcing in the AMOC weakening described here.Timofeev, A., Migdisov, A.A., Williams-Jones, A.E., Roback, R., Nelson, A.T., Xu, H., 2018. Uranium transport in acidic brines under reducing conditions. Nature Communications 9, Article 1469. behavior of uranium in environments, ranging from those of?natural systems responsible for the formation of uranium deposits to those of?nuclear reactors providing 11% of the world’s electricity, is governed by processes involving high-temperature aqueous solutions. It has been well documented that uranium is mobile in aqueous solutions in its oxidized, U6+ state, whereas in its reduced, U4+ state, uranium has been assumed to be immobile. Here, we present experimental evidence from high temperature (>100?°C) acidic brines that invalidates?this assumption. Our experiments have identified a new uranium chloride species (UCl4°) that is more stable under reducing than oxidized conditions. These results indicate that uranium is mobile under reducing conditions and necessitate a re-evaluation of the mobility of uranium, particularly in ore deposit models involving this metal. Regardless of the scenario considered, reducing conditions can no longer be considered a guarantee of uranium immobility.Todaro, S., Rigo, M., Randazzo, V., Di Stefano, P., 2018. The end-Triassic mass extinction: A new correlation between extinction events and δ13C fluctuations from a Triassic-Jurassic peritidal succession in western Sicily. Sedimentary Geology 368, 105-113. new δ13Ccarb curve was obtained from an expanded peritidal succession in western Sicily and was used to investigate the relationships between isotopic signatures and biological events on carbonate platforms across the Triassic-Jurassic boundary (TJB). The resulting curve shows two main negative carbon isotopic excursions (CIEs) that fit well with the “Initial” and “Main” CIEs that are recognized worldwide and linked to the End-Triassic Extinction (ETE). In the studied section, the first negative CIE marks the disappearance of the large megalodontids, which were replaced by small and thin-shelled specimens, while the “Main” CIE corresponds to the last occurrence (LO) of the megalodontids and, approximately 50?m upsection, to the total demise of the Rhaetian benthic foraminifer community. Upward, the carbon curve shows a positive trend (ca. +1‰) and a gradual recovery of the benthic communities after an approximately 10?m-thick barren interval populated only by the problematic alga </topics/earth-and-planetary-sciences/alga> Thaumatoporella parvovesiculifera.A comparison between the Mt. Sparagio δ13Ccarb curve and other coeval Ccarb and Corg curves from carbonate platform, ramp and deep basin successions indicates similar isotopic trends; however, the diverse magnitudes and responses of benthic communities confirm that the carbon cycle perturbations have been globally significant, and were influenced by external forces such as CAMP volcanism. The multiphase nature of the extinction pulses could have been caused by local environmental changes related to transgression/regression phenomena. Overall, this study adds new data and a new timing to the effect of the acidification process on carbon productivity and benthic communities in different environments across the TJB.Todd, P.M., Miller, G.F., 2018. The evolutionary psychology of extraterrestrial intelligence: Are there universal adaptations in search, aversion, and signaling? Biological Theory 13, 131-141. understand the possible forms of extraterrestrial intelligence (ETI), we need not only astrobiology theories about how life evolves given habitable planets, but also evolutionary psychology theories about how intelligence emerges given life. Wherever intelligent organisms evolve, they are likely to face similar behavioral challenges in their physical and social worlds. The cognitive mechanisms that arise to meet these challenges may then be copied, repurposed, and shaped by further evolutionary selection to deal with more abstract, higher-level cognitive tasks such as conceptual reasoning, symbolic communication, and technological innovation, while retaining traces of the earlier adaptations for solving physical and social problems. These traces of evolutionary pathways may be leveraged to gain insight into the likely cognitive processes of ETIs. We demonstrate such analysis in the domain of search strategies and show its application in the domains of emotional aversions and social/sexual signaling. Knowing the likely evolutionary pathways to intelligence will help us to better search for and process any alien signals from the search for ETIs (SETI) and to assess the likely benefits, costs, and risks of humans actively messaging ETIs (METI).Tominski, C., Heyer, H., L?sekann-Behrens, T., Behrens, S., Kappler, A., 2018. Growth and population dynamics of the anaerobic Fe(II)-oxidizing and nitrate-reducing enrichment culture KS. Applied and Environmental Microbiology 84, Article e02173-17.: Most isolated nitrate-reducing Fe(II)-oxidizing microorganisms are mixotrophic, meaning that Fe(II) is chemically oxidized by nitrite that forms during heterotrophic denitrification, and it is debated to which extent Fe(II) is enzymatically oxidized. One exception is the chemolithoautotrophic enrichment culture KS, a consortium consisting of a dominant Fe(II) oxidizer, Gallionellaceae sp., and less abundant heterotrophic strains (e.g., Bradyrhizobium sp., Nocardioides sp.). Currently, this is the only nitrate-reducing Fe(II)-oxidizing culture for which autotrophic growth has been demonstrated convincingly for many transfers over more than 2 decades. We used 16S rRNA gene amplicon sequencing and physiological growth experiments to analyze the community composition and dynamics of culture KS with various electron donors and acceptors. Under autotrophic conditions, an operational taxonomic unit (OTU) related to known microaerophilic Fe(II) oxidizers within the family Gallionellaceae dominated culture KS. With acetate as an electron donor, most 16S rRNA gene sequences were affiliated with Bradyrhizobium sp. Gallionellaceae sp. not only was able to oxidize Fe(II) under autotrophic and mixotrophic conditions but also survived over several transfers of the culture on only acetate, although it then lost the ability to oxidize Fe(II). Bradyrhizobium spp. became and remained dominant when culture KS was cultivated for only one transfer under heterotrophic conditions, even when conditions were reverted back to autotrophic in the next transfer. This study showed a dynamic microbial community in culture KS that responded to changing substrate conditions, opening up questions regarding carbon cross-feeding, metabolic flexibility of the individual strains in KS, and the mechanism of Fe(II) oxidation by a microaerophile in the absence of O2. Importance: Nitrate-reducing Fe(II)-oxidizing microorganisms are present in aquifers, soils, and marine and freshwater sediments. Most nitrate-reducing Fe(II) oxidizers known are mixotrophic, meaning that they need organic carbon to continuously oxidize Fe(II) and grow. In these microbes, Fe(II) was suggested to be chemically oxidized by nitrite that forms during heterotrophic denitrification, and it remains unclear whether or to what extent Fe(II) is enzymatically oxidized. In contrast, the enrichment culture KS was shown to oxidize Fe(II) autotrophically coupled to nitrate reduction. This culture contains the designated Fe(II) oxidizer Gallionellaceae sp. and several heterotrophic strains (e.g., Bradyrhizobium sp.). We showed that culture KS is able to metabolize Fe(II) and a variety of organic substrates and is able to adapt to dynamic environmental conditions. When the community composition changed and Bradyrhizobium became the dominant community member, Fe(II) was still oxidized by Gallionellaceae sp., even when culture KS was cultivated with acetate/nitrate [Fe(II) free] before being switched back to Fe(II)/nitrate. Tominski, C., L?sekann-Behrens, T., Ruecker, A., Hagemann, N., Kleindienst, S., Mueller, C.W., H?schen, C., K?gel-Knabner, I., Kappler, A., Behrens, S., 2018. Insights into carbon metabolism provided by fluorescence in situ hybridization-secondary ion mass spectrometry imaging of an autotrophic, nitrate-reducing, Fe(ii)-oxidizing enrichment culture. Applied and Environmental Microbiology 84, Article e02166-17.: The enrichment culture KS is one of the few existing autotrophic, nitrate-reducing, Fe(II)-oxidizing cultures that can be continuously transferred without an organic carbon source. We used a combination of catalyzed amplification reporter deposition fluorescence in situ hybridization (CARD-FISH) and nanoscale secondary ion mass spectrometry (NanoSIMS) to analyze community dynamics, single-cell activities, and interactions among the two most abundant microbial community members (i.e., Gallionellaceae sp. and Bradyrhizobium spp.) under autotrophic and heterotrophic growth conditions. CARD-FISH cell counts showed the dominance of the Fe(II) oxidizer Gallionellaceae sp. under autotrophic conditions as well as of Bradyrhizobium spp. under heterotrophic conditions. We used NanoSIMS to monitor the fate of 13C-labeled bicarbonate and acetate as well as 15N-labeled ammonium at the single-cell level for both taxa. Under autotrophic conditions, only the Gallionellaceae sp. was actively incorporating 13C-labeled bicarbonate and 15N-labeled ammonium. Interestingly, both Bradyrhizobium spp. and Gallionellaceae sp. became enriched in [13C]acetate and [15N]ammonium under heterotrophic conditions. Our experiments demonstrated that Gallionellaceae sp. was capable of assimilating [13C]acetate while Bradyrhizobium spp. were not able to fix CO2, although a metagenomics survey of culture KS recently revealed that Gallionellaceae sp. lacks genes for acetate uptake and that the Bradyrhizobium sp. carries the genetic potential to fix CO2. The study furthermore extends our understanding of the microbial reactions that interlink the nitrogen and Fe cycles in the environment. Importance: Microbial mechanisms by which Fe(II) is oxidized with nitrate as the terminal electron acceptor are generally referred to as “nitrate-dependent Fe(II) oxidation” (NDFO). NDFO has been demonstrated in laboratory cultures (such as the one studied in this work) and in a variety of marine and freshwater sediments. Recently, the importance of NDFO for the transport of sediment-derived Fe in aquatic ecosystems has been emphasized in a series of studies discussing the impact of NDFO for sedimentary nutrient cycling and redox dynamics in marine and freshwater environments. In this article, we report results from an isotope labeling study performed with the autotrophic, nitrate-reducing, Fe(II)-oxidizing enrichment culture KS, which was first described by Straub et al. (1) about 20 years ago. Our current study builds on the recently published metagenome of culture KS (2). Top?uo?lu, B.D., Meydan, C., Orellana, R., Holden, J.F., 2018. Formate hydrogenlyase and formate secretion ameliorate H2 inhibition in the hyperthermophilic archaeon Thermococcus paralvinellae. Environmental Microbiology 20, 949-957. hyperthermophilic heterotrophs in the genus Thermococcus produce H2 in the absence of S° and have up to seven hydrogenases, but their combined physiological roles are unclear. Here, we show which hydrogenases in Thermococcus paralvinellae are affected by added H2 during growth without S°. Growth rates and steady‐state cell concentrations decreased while formate production rates increased when T. paralvinallae was grown in a chemostat with 65 ?M of added H2(aq). Differential gene expression analysis using RNA‐Seq showed consistent expression of six hydrogenase operons with and without added H2. In contrast, expression of the formate hydrogenlyase 1 (fhl1) operon increased with added H2. Flux balance analysis showed H2 oxidation and formate production using FHL became an alternate route for electron disposal during H2 inhibition with a concomitant increase in growth rate relative to cells without FHL. T. paralvinellae also grew on formate with an increase in H2 production rate relative to growth on maltose or tryptone. Growth on formate increased fhl1 expression but decreased expression of all other hydrogenases. Therefore, Thermococcus that possess fhl1 have a competitive advantage over other Thermococcus species in hot subsurface environments where organic substrates are present, S° is absent and slow H2 efflux causes growth inhibition. Tribovillard, N., Petit, A., Quijada, M., Riboulleau, A., Sansjofre, P., Thomazo, C., Huguet, A., Birgel, D., Averbuch, O., 2018. A genetic link between synsedimentary tectonics-expelled fluids, microbial sulfate reduction and cone-in-cone structures. Marine and Petroleum Geology 93, 437-450. late Jurassic (Tithonian) marlstones of the Boulonnais area (English Channel, France) contains diagenetic carbonate beds and nodules. Some nodules exhibit cone-in-cone structures on their lower face. We studied such nodules using various techniques of imaging and chemical (major and trace-elements) and isotopic analyses (Ccarb, Corg, O and S stable isotopes). We interpret the cone-in-cone to be the end product of carbonate-nodule formation during early diagenesis. The diagenetic carbonate precipitation was induced by microbial activity (bacteria and(?) archeae) fueled by upward-migrating fluids. Fluid expulsion was itself triggered by synsedimentary fault movements. Under such circumstances, cone-in-cone structures can form during early diagenesis as the result of bacterially-mediated sulfate reduction, possibly coupled to sulfate-dependent anaerobic oxidation of methane. This genetical scheme may be transposed to many other settings.Trivella, D.B.B., de Felicio, R., 2018. The tripod for bacterial natural product discovery: Genome mining, silent pathway induction, and mass spectrometry-based molecular networking. mSystems 3, DOI: 10.1128/mSystems.00160-17. products are the richest source of chemical compounds for drug discovery. Particularly, bacterial secondary metabolites are in the spotlight due to advances in genome sequencing and mining, as well as for the potential of biosynthetic pathway manipulation to awake silent (cryptic) gene clusters under laboratory cultivation. Further progress in compound detection, such as the development of the tandem mass spectrometry (MS/MS) molecular networking approach, has contributed to the discovery of novel bacterial natural products. The latter can be applied directly to bacterial crude extracts for identifying and dereplicating known compounds, therefore assisting the prioritization of extracts containing novel natural products, for example. In our opinion, these three approaches—genome mining, silent pathway induction, and MS-based molecular networking—compose the tripod for modern bacterial natural product discovery and will be discussed in this perspective.Tuovinen, J.P., Aurela, M., Hatakka, J., R?s?nen, A., Virtanen, T., Mikola, J., Ivakhov, V., Kondratyev, V., Laurila, T., 2018. Interpreting eddy covariance data from heterogeneous Siberian tundra: land cover-specific methane fluxes and spatial representativeness. Biogeosciences Discussions 2018, 1-36. non-uniform spatial integration inherent in the eddy covariance (EC) method provides an additional challenge for data interpretation when fluxes are measured in a heterogeneous environment, as the contribution of different surface types varies with flow conditions, potentially resulting in a bias as compared to the true areally averaged fluxes and surface attributes. We modelled flux footprints and characterized the spatial scale of our EC measurements at Tiksi, a tundra site in northern Siberia, including a comparison of different source area definitions. We used leaf area index (LAI) and land cover class (LCC) data, derived from very high spatial resolution satellite imagery and field surveys, and quantified the sensor location bias. We found that methane (CH4) fluxes varied strongly with wind direction (from ?0.09 to 0.59?μg?m?2?s?1 on average), reflecting the distribution of different LCCs. Using footprint weights of grouped LCCs as explanatory variables for the measured CH4 flux, we then developed a multiple regression model to estimate LCC-specific fluxes. This model showed that wet fen and graminoid tundra patches in locations with a high topography-based wetness index acted as strong CH4 sources (0.95?μg?m?2?s?1), while mineral soils were significant sinks (?0.13?μg?m?2?s?1). Finally, to assess the representativeness of CH4 flux measurements, we upscaled the LCC-specific fluxes to different spatial scales. This assessment showed that, despite the surface heterogeneity and rather poor representativeness of EC data with respect to the areally averaged LAI and coverage of some LCCs, the mean CH4 flux measured during summer 2014 was close to the corresponding balance upscaled to an area of 6.3?km2, with a location bias of 14?%. We recommend that EC site descriptions in a heterogeneous environment should be complemented with footprint-weighted high-resolution data on vegetation and other relevant site characteristics.Twaróg, A., Stefaniuk, M., Sechman, H., Guzy, P., 2018. Integrated analysis of geoelectric and surface geochemical data for exploration of subsurface hydrocarbon accumulations (Carpathian Foredeep, SE Poland). Journal of Petroleum Science and Engineering 167, 524-537. search for hydrocarbon deposits in the Carpathian Foredeep is dominate by seismic methods. However, chances for additional discoveries of oil and gas will be increased by the integration of geochemical methods with non-seismic methods. The authors document mutual relationships between data obtained from surface geochemical survey and surface geoelectric survey. The geoelectric and geochemical surveys were run along 8 linear profiles positioned over the Rudka gas deposit discovered in Miocene sediments. This deposit is located over the margin of the Ryszkowa Wola Horst (Carpathian Foredeep). The Rudka deposit accumulates microbial gas generated under strictly defined conditions (microbial reduction of carbon dioxide). Soil gas samples were collected from a depth of 1.2?m?at 177 sites and analyzed for methane, alkanes, alkenes, and non-hydrocarbon components. Maximum concentrations of CH4, total alkanes C2-C5 and total alkenes C2-C4 are 1200.0?ppm, 16.49?ppm and 0.289?ppm, respectively. The high concentrations of methane correlated with high values of C1/∑(C2-C4) ratio indicate the presence of recent (microbial) methane whereas higher alkanes detected in soil gases originated from deep hydrocarbon accumulations. Two methodological variants of magnetotelluric survey were applied: natural field magnetotelluric soundings and controlled-source audiomagnetotelluric profiling. The interpreted resistivity values of Miocene sediments change from 0.6 to 20?Ωm but higher resistivities, locally exceeding 100?Ωm also occur in the near-surface zone. The lateral decreases of resistivity observed in the cross-sections may be linked to tectonic discontinuities. Changes of resistivity values identified in the magnetotelluric profiles and interpreted as the signs of “gas chimneys” correlate well with anomalous concentrations of total alkanes C2-C5.The multistage analysis of the results of surface geochemical and geoelectric surveys demonstrated that gas-saturated zones may extend beyond the known contour of the Rudka gas deposit. These results demonstrate that geoelectric and geochemical data collected in the near-surface zone are valuable complements of conventional hydrocarbon exploration methods.Uchimoto, K., Nishimura, M., Kita, J., Xue, Z., 2018. Detecting CO2 leakage at offshore storage sites using the covariance between the partial pressure of CO2 and the saturation of dissolved oxygen in seawater. International Journal of Greenhouse Gas Control 72, 130-137. option to detect CO2 leakage from deep geological storage under the seabed is monitoring the partial pressure of CO2 (pCO2) in the sea. One of the challenges of this technique is to differentiate pCO2 elevations caused by CO2 leakage from variations in the natural baseline (which varies due to seasonal and other factors). This paper compares a covariance threshold for anomalous pCO2 (a threshold based on pCO2 and dissolved oxygen), with annual and seasonal constant thresholds, using data observed in two hydrologically contrasting areas in Osaka Bay, Japan. In one of these locations the water column is typically stratified throughout the year, whereas at the other it is vertically mixed. The covariance threshold often but not consistently outperforms the constant thresholds, but is effective in all the cases analyzed in the present study. In any season in the mixed area, and in winter in the stratified area, the possibility of false-negatives in the seasonal threshold method is smaller than or comparable with that in the covariance threshold one. In areas with large natural pCO2 variations, such as during summer in the stratified area, the covariance threshold method is efficient in detecting CO2 leakage whereas the seasonal threshold method is of little use. With a good understanding of local conditions, monitoring pCO2 with the covariance threshold method is a potentially useful but not sufficient option for leakage detection in the marine environment.Umeh, A.C., Vázquez-Cuevas, G.M., Semple, K.T., 2018. Mineralisation of 14C-phenanthrene in PAH-diesel contaminated soil: Impact of Sorghum bicolor and Medicago sativa mono- or mixed culture. Applied Soil Ecology 125, 46-55. biodegradation can offer a cost-effective and sustainable approach for the bioremediation of PAHs in soil. As such, selecting the most appropriate plant species is important. The potential for plant-assisted biodegradation of complex PAH-diesel mixtures in soil by sorghum (Sorghum bicolor) and alfalfa (Medicago sativa) grown as monocultures and mixed cultures using 14C-contaminants has not been widely reported. The objective of this study was to assess 14C-phenanthrene mineralisation profiles in mixtures of PAH-diesel in soil in the presence of Sorghum bicolor and Medicago sativa. Soil was spiked with PAHs and diesel, after which M. sativa and S. bicolor were introduced and grown as mono- or mixed- cultures. The toxicity of the PAH-diesel oil mixture in the planted treatments, as well as its effect on the mineralisation of 14C-phenanthrene were evaluated. Monocultures of both plant species tolerated the complex PAH-diesel mixtures based on growth and survival, and increased rates and extents of 14C-phenanthrene mineralisation in soil. The influence of PAH concentration on 14C-phenanthrene mineralisation profiles varied in planted and unplanted treatments. The rates and extents of 14C-phenanthrene mineralisation tended to decrease in diesel amended soil, especially at low PAH concentrations. To the best of the authors’ knowledge, this is the first report of 14C-phenanthrene mineralisation patterns in complex PAH-diesel oil mixtures contaminated soil especially with respect to the specified plant species. The findings offer new insights on mono- and multi-species phytotoxicity as well as plant-assisted biodegradation of PAH mixtures in soil which may be useful in the risk assessment and remediation of contaminated sites.Usman, M., Hanna, K., Faure, P., 2018. Remediation of oil-contaminated harbor sediments by chemical oxidation. Science of The Total Environment 634, 1100-1107. hydrocarbons are widespread pollutants in sub-surface sediments with serious threats to terrestrial and aquatic environment. However, very limited data is available about remediation of historically contaminated sediments. This study reports the use of magnetite-catalyzed chemical oxidation (H2O2 and Na2S2O8) to degrade oil hydrocarbons in aged contaminated sediments. For this purpose, oil contaminated sediments were sampled from three different locations in France including two harbors and one petroleum industrial channel. These sediments were characterized by different hydrocarbon index (HI) values (3.7–9.0 g kg?1), total organic carbon contents (1.9%–8.4%) and textures (sand, slit loam and silt). Chemical oxidation was performed in batch system for one week at circumneutral pH by: H2O2 alone, H2O2/Fe(II), H2O2/magnetite, Na2S2O8 alone, Na2S2O8/Fe(II), and Na2S2O8/magnetite. Results obtained by GC-FID indicated substantial hydrocarbon degradation (40–70%) by H2O2/magnetite and Na2S2O8/magnetite. However, oxidants alone or with soluble Fe(II) caused small degradation (<5%). In the presence of H2O2/magnetite, degradation of extractable organic matter and that of HI were highly correlated. However, no such correlation was observed for Na2S2O8/magnetite which resulted in higher removal of HI indicating its selective oxidation behavior. Treatment efficiency was negatively influenced by organic carbon and carbonate contents. For being the first study to report chemical oxidation of oil hydrocarbons in real contaminated sediments, it may have practical implications to design a remediation strategy for target contaminants.Valdespino-Castillo, P.M., Hu, P., Merino-Ibarra, M., López-Gómez, L.M., Cerqueda-García, D., González-De Zayas, R., Pi-Puig, T., Lestayo, J.A., Holman, H.-Y., Falcón, L.I., 2018. Exploring biogeochemistry and microbial diversity of extant microbialites in Mexico and Cuba. Frontiers in Microbiology 9, 510. doi: 10.3389/fmicb.2018.00510. are modern analogs of ancient microbial consortia that date as far back as the Archaean Eon. Microbialites have contributed to the geochemical history of our planet through their diverse metabolic capacities that mediate mineral precipitation. These mineral-forming microbial assemblages accumulate major ions, trace elements and biomass from their ambient aquatic environments; their role in the resulting chemical structure of these lithifications needs clarification. We studied the biogeochemistry and microbial structure of microbialites collected from diverse locations in Mexico and in a previously undescribed microbialite in Cuba. We examined their structure, chemistry and mineralogy at different scales using an array of nested methods including 16S rRNA gene high-throughput sequencing, elemental analysis, X-Ray fluorescence (XRF), X-Ray diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS), Fourier Transformed Infrared (FTIR) spectroscopy and Synchrotron Radiation-based Fourier Transformed Infrared (SR-FTIR) spectromicroscopy. The resulting data revealed high biological and chemical diversity among microbialites and specific microbe to chemical correlations. Regardless of the sampling site, Proteobacteria had the most significant correlations with biogeochemical parameters such as organic carbon (Corg), nitrogen and Corg:Ca ratio. Biogeochemically relevant bacterial groups (dominant phototrophs and heterotrophs) showed significant correlations with major ion composition, mineral type and transition element content, such as cadmium, cobalt, chromium, copper and nickel. Microbial-chemical relationships were discussed in reference to microbialite formation, microbial metabolic capacities and the role of transition elements as enzyme cofactors. This paper provides an analytical baseline to drive our understanding of the links between microbial diversity with the chemistry of their lithified precipitations.van Santvoort, J., Golombok, M., 2018. Improved recovery from fractured oil reservoirs. Journal of Petroleum Science and Engineering 167, 28-36. loss through natural fractures in oil reservoirs can be overcome using flow induced viscoelastic surfactant (FIVES) solutions. Single phase tests show higher flow resistance in fractures compared to matrix. This reduces the fluid lost through the fracture. During decane displacement, the amount of fluid lost through the fracture is lowered due to this increased local flow resistance. Improved recovery is obtained and the pore volume injected at break-through is reduced from 2.5 PV to ca. 1.0 PV. These results translate to a prolonged economic lifespan of a fractured heterogeneous reservoir and a significant reduction in post-processing costs.van Soelen, E.E., Twitchett, R.J., Kürschner, W.M., 2018. Salinity changes and anoxia resulting from enhanced run-off during the late Permian global warming and mass extinction event. Climate of the Past 14, 441-453. late Permian biotic crisis had a major impact on marine and terrestrial environments. Rising CO2 levels following Siberian Trap volcanic activity were likely responsible for expanding marine anoxia and elevated water temperatures. This study focuses on one of the stratigraphically most expanded Permian–Triassic records known, from Jameson Land, East Greenland. High-resolution sampling allows for a detailed reconstruction of the changing environmental conditions during the extinction event and the development of anoxic water conditions. Since very little is known about how salinity was affected during the extinction event, we especially focus on the aquatic palynomorphs and infer changes in salinity from changes in the assemblage and morphology. The start of the extinction event, here defined by a peak in spore?:?pollen, indicating disturbance and vegetation destruction in the terrestrial environment, postdates a negative excursion in the total organic carbon, but predates the development of anoxia in the basin. Based on the newest estimations for sedimentation rates, the marine and terrestrial ecosystem collapse took between 1.6 and 8?kyr, a much shorter interval than previously estimated. The palynofacies and palynomorph records show that the environmental changes can be explained by enhanced run-off and increased primary productivity and water column stratification. A lowering in salinity is supported by changes in the acritarch morphology. The length of the processes of the acritarchs becomes shorter during the extinction event and we propose that these changes are evidence for a reduction in salinity in the shallow marine setting of the study site. This inference is supported by changes in acritarch distribution, which suggest a change in palaeoenvironment from open marine conditions before the start of the extinction event to more nearshore conditions during and after the crisis. In a period of sea-level rise, such a reduction in salinity can only be explained by increased run-off. High amounts of both terrestrial and marine organic fragments in the first anoxic layers suggest that high run-off, increased nutrient availability, possibly in combination with soil erosion, are responsible for the development of anoxia in the basin. Enhanced run-off could result from changes in the hydrological cycle during the late Permian extinction event, which is a likely consequence of global warming. In addition, vegetation destruction and soil erosion may also have resulted in enhanced run-off. Salinity stratification could potentially explain the development of anoxia in other shallow marine sites. The input of freshwater and related changes in coastal salinity could also have implications for the interpretation of oxygen isotope records and seawater temperature reconstructions at some sites.Vasudevan, V., Gayathri, K.V., Krishnan, M.E.G., 2018. Bioremediation of a pentacyclic PAH, dibenz(a,h)anthracene- A long road to trip with bacteria, fungi, autotrophic eukaryotes and surprises. Chemosphere 202, 387-399.(a,h)Anthracene (DBahA), classified as a probable human carcinogen (B2) is the first Poly Aromatic Hydrocarbons (PAH) to be chemically purified and used for cancer-based studies. Till date, only 30 papers focus on the bioremediation aspects of DBahA out of more than 200 research publications for each of the other 15 priority PAHs. Thus, the review raises an alarm and calls for efficient bioremediation strategies for considerable elimination of this compound from the environment. This article reviews and segregates the available papers on DBahA bioremoval from the beginning till date into bacteria, fungi and plant-mediated remediation and offers suggestions for the most competent and cost-effective modes to bioremove DBahA from the environment. One of the proficient ways to get rid of this PAH could with the use of biosurfactant-enriched bacterial consortium in DBahA polluted environment, which is given considerable importance here. Among the bacterial and fungal microbiomes, unquestionably the former are the beneficiaries which utilize the breakdown products of this PAH metabolized by the latter. Nevertheless, the use of plant communities for efficient DBahA utilization through fibrous root system is also discussed at length. The current status of DBahA as reflected by the publications at <; and recommendations among the explored groups [bacterial/fungal/plant communities] for better DBahA elimination are pointed out. Finally, the review emphasizes the pros and cons of all the methodologies used for selective/combinatorial removal of DBahA and present the domain to the researchers to carry forward by incorporating their individual ideas.Wade, L., 2018. Ancient DNA untangles South Asian roots. Science 360, 252., the population of South Asia is divided into dozens of ethnic, linguistic, and religious groups that live side by side—but not always in harmony. A contentious border separates India and Pakistan; political movements draw stark lines between India's Muslim and Hindu populations. Groups don't mix much, as people tend to marry those who share their ethnicity and tongue.Now, a study of the first ancient DNA recovered from South Asia shows that populations there mingled repeatedly thousands of years ago. Nearly all of the Indian subcontinent's ethnic and linguistic groups are the product of three ancient Eurasian populations who met and mixed: local hunter-gatherers, Middle Eastern farmers, and Central Asian herders. Three similar groups also mingled in ancient Europe, giving the two subcontinents surprisingly parallel histories.The study, presented here last week at the meeting of the American Association of Physical Anthropologists and in a preprint on the bioRxiv server, sheds light on where these populations came from and when they arrived in South Asia. It also strengthens the claim that Proto-Indo-European (PIE)—the ancestral language that gave rise to modern languages from English to Russian to Hindi—originated on the steppes of Asia.“It's first-rate work,” says Partha Majumder, a geneticist at the National Institute of Biomedical Genomics in Kalyani, India. He found hints of similar genetic patterns in his previous studies, but the addition of ancient DNA makes the new conclusions stronger, he says. “It's absolutely stunning.”Priya Moorjani, a geneticist at the University of California, Berkeley, studies how South Asian populations relate to each other and to others around the world. In previous work, she analyzed the genomes of nearly 600 modern Indians and Pakistanis from 73 ethno-linguistic groups in South Asia. Her team found that almost all people living in India today carry ancestry from two ancient populations: Ancestral North Indians, who were more related to people from Central Asia, the Middle East, the Caucasus, and Europe; and Ancestral South Indians, who were more related to indigenous groups living in the subcontinent today. But without DNA from ancient people, Moorjani couldn't be sure who gave rise to those ancestral populations, or when.Moorjani, David Reich of Harvard University, and Kumarasamy Thangaraj of the Centre for Cellular and Molecular Biology in Hyderabad, India, spent years searching for ancient DNA in South Asia, where hot climates might degrade it. Finally, their team recovered and analyzed ancient genomes from 65 individuals who lived in northern Pakistan between 1200 B.C.E. and 1 C.E. They also analyzed 132 ancient genomes from Iran and southern Central Asia, and 165 from the steppes of Kazakhstan and Russia, and compared them with published ancient and modern genomes. These data allowed them to reconstruct when different populations arrived in South Asia and how they interacted.Between 4700 and 3000 B.C.E., farmers from Iran mixed with hunter-gatherers indigenous to South Asia, Moorjani said. This combination of ancestries was found in the DNA of skeletal remains from sites in Turkmenistan and Iran known to have been in contact with the Indus Valley civilization, which thrived in Pakistan and northwest India starting around 3300 B.C.E. (Science, 6 June 2008, p. 1276). The researchers dub this population “Indus periphery.” The 65 ancient people from Pakistan also show this combination, although they all lived after the Indus civilization declined. The researchers suspect that “Indus periphery” people actually may have been the founders of Indus society, although without ancient DNA from Indus Valley burials, they can't be sure.Still, Moorjani's team sees this ancient mixture of Iranian farmers and South Asian hunter-gatherers all over South Asia today. As the Indus Valley civilization declined after 1300 B.C.E., some Indus periphery individuals moved south to mix with indigenous populations there, forming the Ancestral South Indian population, which today is more prominent in people who speak Dravidian languages such as Tamil and Kannada, and in those belonging to lower castes.Meanwhile, herders from the Eurasian steppe moved into the northern part of the subcontinent and mixed with Indus periphery people still there, forming the Ancestral North Indian population. Today, people who belong to higher castes and those who speak Indo-European languages such as Hindi and Urdu tend to have more of this ancestry. Shortly after, these two already mixed groups mixed with each other, giving rise to the populations living in India today.“Strikingly, this is very similar to the pattern we see in Europe,” Moorjani said. Around 7000 B.C.E., agriculture spread into both Europe and South Asia with farmers from Anatolia and Iran, respectively, who each mixed with local hunter-gatherer populations. After about 3000 B.C.E., Yamnaya pastoralists from the Central Asian steppe swept both east and west, into Europe and South Asia, bringing the wheel and perhaps cannabis (see p. 249).Earlier genetic work had linked the arrival of these herders to the spread of Indo-European languages in Europe. But other researchers, including archaeologist Colin Renfrew of the University of Cambridge in the United Kingdom, had argued that the earlier Anatolian farmers were the original PIE speakers. The new data “make a strong case” for the Yamnaya as carriers of Indo-European languages, Renfrew says. But he still thinks Anatolian farmers could have spoken the earliest language in that family.Wade, L., 2018. Latin America's lost histories revealed. Science 360, 137-138. you walked the cobblestone streets and bustling markets of 16th and 17th century Mexico City, you would see people born all over the world: Spanish settlers on their way to mass at the cathedral built atop Aztec ruins. Indigenous people from around the Americas, including soldiers who had joined the Spanish cause. Africans, both enslaved and free, some of whom had been among the first conquistadors. Asians, who traveled to Mexico on Spanish galleons, some by choice and some in bondage. All these populations met and mingled for the first time in colonial Latin America.Historical documents describe this cultural mixture, but now international teams of researchers are enriching our view by analyzing the genomes of people today. Aided by sophisticated statistics and worldwide genetic databases, they can tease apart ancestry and population mixing with more nuance than ever before. The results, reported at a meeting here this week and in a preprint, tell stories of Latin America that have been largely forgotten or were never recorded in historical documents. From the immigration of enslaved Filipinos to that of formerly Jewish families forbidden to travel to the colonies, hidden histories are emerging.“It's helping us to recognize the ways that really fine-scale historical experiences and practices have left this deeply significant imprint on our genomes,” says Deborah Bolnick, an anthropological geneticist at the University of Texas here.Juan Esteban Rodríguez, a graduate student in population genetics at the National Laboratory of Genomics for Biodiversity (LANGEBIO) in Irapuato, Mexico, initially planned to study a recent thread in the global tapestry that is Mexican ancestry. Starting in the 19th century, many Chinese immigrants moved to Mexico to construct railroads in the country's northern states. Growing up near the U.S. border, Rodríguez knew this history well, and he wanted to see whether he could identify the Chinese immigrants' genetic contribution to the modern Mexican population.But when he searched a database of 500 Mexican genomes—initially assembled for biomedical studies—and sought genetic variants more common in Asian populations, he found a surprise. Some people from northern Mexico did have significant Asian ancestry, but they weren't the only ones. Rodríguez discovered that about one-third of the people sampled in Guerrero, the Pacific coastal state that lies nearly 2000 kilometers south of the U.S. border, also had up to 10% Asian ancestry, significantly more than most Mexicans. And when he compared their genomes to those of people in Asia today, he found that they were most closely related to populations from the Philippines and Indonesia.Rodríguez and his adviser, Andrés Moreno-Estrada, a population geneticist at LANGEBIO, turned to the historical record to figure out who these people's ancestors might be. They learned from historians who study ship manifests and other trade documents that during the 16th and 17th centuries, Spanish galleons sailed between Manila and the port of Acapulco in Guerrero, carrying goods and people, including enslaved Asians. Although historians knew of this transpacific slave trade, the origins of its victims were lost. Once they landed in Mexico, they were all recorded as “chinos”—Chinese, says Moreno-Estrada, who will present the work this weekend at the American Association of Physical Anthropologists (AAPA) annual meeting here. “We're uncovering these hidden stories of slavery and people who lost their identities when they disembarked in a whole new country.”Other researchers study the legacy of another marginalized group in colonial Mexico: Africans. Tens of thousands of enslaved and free Africans lived in Mexico during the 16th and 17th centuries, outnumbering Europeans, and today almost all Mexicans carry about 4% African ancestry. The percentage is much higher in some communities, says geneticist María ?vila-Arcos of the International Laboratory for Human Genome Research in Juriquilla, Mexico. She found that in Afro-descendent communities in Guerrero and Oaxaca, many of which remain isolated, people had about 26% African ancestry, most of it from West Africa.Other data also suggest a strong African presence in colonial Mexico. Bioarchaeologist Corey Ragsdale of Southern Illinois University in Edwardsville and his colleagues examined skeletons for dental and cranial traits that tend to be more common among Africans. They estimated that 20% to 40% of the people buried in cemeteries in Mexico City between the 16th and 18th centuries had some African ancestry, as they will present this weekend at the AAPA meeting. “It could be that Africans played as much of a role in developing population structure, and in fact developing the [Spanish] empire, as Europeans did,” Ragsdale says.?vila-Arcos hopes to use genetic data to trace the ancestors of those in her study back to specific West African groups or regions. She's also found significant Asian ancestry in some of her volunteers, likely an echo of communities once formed by enslaved Africans and Asians on the Pacific coast.Some Europeans carried hidden histories with them to colonial Latin America. A preprint recently posted on the bioRxiv server used genetic data from more than 6500 people born in Brazil, Chile, Colombia, Mexico, and Peru to tease apart how specific Native American groups and multiple populations from the Iberian peninsula contributed to modern genomes. “It's undoubtedly the most comprehensive genetic analysis of Latin American populations to date,” ?vila-Arcos says. (The authors declined to comment because the paper has been submitted to a peer-reviewed journal.) One striking finding was that genetic variants common in the eastern Mediterranean and North Africa, and especially in Sephardic Jews, show up all over Latin America, in nearly a quarter of the individuals sampled.The authors, led by geneticists Andrés Ruiz-Linares of Fudan University in Shanghai, China, and Garrett Hellenthal of University College London, trace a significant portion of this ancestry to conversos, or Jews who converted to Christianity in 1492, when Spain expelled those who refused to do so. Conversos were prohibited from migrating to the Spanish colonies, though a few are known to have made the trip anyway. But widespread Sephardic ancestry in Latin America implies that migration was much more common than records suggest.For Ragsdale, the work serves as a reminder that even migrations scientists think are well understood can contain surprises. “The way we think about colonization is simplified,” Ragsdale says. “We're missing a lot of subtleties here.”Waktola, H.D., Kulsing, C., Nolvachai, Y., Marriott, P.J., 2018. High temperature multidimensional gas chromatographic approach for improved separation of triacylglycerols in olive oil. Journal of Chromatography A 1549, 77-84. multidimensional gas chromatographic (H/C MDGC) methods under suitable flow and high temperature (T) program conditions were developed to separate olive oil (TAGs). Different column sets were selected for further evaluation, each with relatively short non-polar first dimension (1D) and mid-polar second dimension (2D) columns of high T limits (350?°C). The 1D separation displayed three major groups of peaks in an area ratio of approximately 5:33:62 (of increasing retention), using flame ionisation detection (FID). Four groups of minor peaks, with 2 of them located between the major peaks, were also detected. The H/C fractions of the minor peaks, and sub-sampled regions across the major peaks eluting from the 1D outlet, were cryotrapped at the 2D inlet. The trapped TAGs then underwent temperature programmed 2D separation. Each of the ‘H/C’ zones generally gave 2–5 – and in some cases more – separated peaks of TAGs on the 2D column, under suitable flow condition and phase polarity that resulted in improved separation. Six sub-sampled H/Cs from various regions of the individual peaks from the 1D column were simultaneously trapped and released to 2D, resulting in apparently more than 22 individual TAG peaks. According to their different retention times, different TAGs were revealed within each of the 3 major groups, using H/C sub-sampling. A comprehensive sampling strategy that covers most of the 1D peaks further revealed the presence of more TAGs in the olive oil sample. This tandem column strategy was able to resolve more components than that usually observed on a single column.Waktola, H.D., Mj?s, S.A., 2018. Chromatographic efficiency of polar capillary columns applied for the analysis of fatty acid methyl esters by gas chromatography. Journal of Separation Science 41, 1582-1592. The chromatographic efficiency that could be achieved in temperature‐programmed gas chromatography was compared for four capillary columns that are typically applied for analysis of fatty acid methyl esters (FAME). Three different carrier gases, hydrogen, helium and nitrogen, were applied. For each experiment, the carrier gas velocities and the temperature rates were varied with a full 9 × 3 design, with nine levels on the carrier gas velocity and temperature rates of 1, 2 or 3°C/min. Response surface methodology was used to create models of chromatographic efficiency as a function of temperature rate and carrier gas velocity. The chromatographic efficiency was defined as the inverse of peak widths measured in retention index units. The final results were standardized so that the efficiencies that could be achieved within a certain time frame, defined by the retention time of the last compound in the chromatogram, could be compared. The results show that there were clear differences in the efficiencies that could be achieved with the different columns and that the efficiency decreased with increasing polarity of the stationary phase. The differences can be explained by higher resistance to mass transfer in the stationary phase in the most polar columns.Wan, Y., Wu, N., Hu, G., Xin, X., Jin, G., Liu, C., Chen, Q., 2018. Reservoir stability in the process of natural gas hydrate production by depressurization in the Shenhu area of the South China Sea. Natural Gas Industry 38, 117-128. stability is a key factor in the production of natural gas hydrate (NGH), and also a prerequisite to ensuring safe and efficient NGH production. However, it has been rarely discussed. To analyze the reservoir stability in the process of NGH production by depressurization in the Shenhu area of the South China Sea, we established a 3D geological model of NGH production by depressurization on the basis of NGH drilling data in this area, which was then discretized by means of nonstructural grid. Then, the mathematical model coupling four fields (i.e. thermal, hydraulic, solid and chemical) was established considering the heat and mass transfer process and sediment transformation process during NGH production. The model was solved by the finite element method together with the nonstructural grid technology, and thus the time–space evolution characteristics of reservoir pore pressure, temperature, NGH saturation and stress in the condition of NGH production by depressurization were determined. Finally, reservoir subsidence, stress distribution and stability in the process of NGH production by depressurization in the Shenhu area were analyzed. The results obtained are as follows. First, the higher the reservoir permeability and the larger the bottom hole pressure drop amplitude are, the larger the subsidence amount and the higher the subsiding speed. Second, as the reservoir pore pressure decreases in the process of production, the effective stress increases and the shear stress near the well increases obviously, resulting in shear damage easily. Third, the increase of effective reservoir stress leads to reservoir subsidence, which mainly occurs in the early stage of NGH production. After the production for 60 days, the maximum reservoir subsidence reached 32 mm and the maximum subsidence of seabed surface was 14 mm. In conclusion, the NGH reservoirs in the Shenhu area of the South China Sea are of low permeability and the effect range of reservoir pressure drop is limited, so the reservoirs would not suffer from shear damage in the sixty-day-production period. Wan, Y., Zhang, S., Tang, S., Pan, Z., Wu, W., 2018. A comparative study of characterization of lower Palaeozoic Niutitang shale in northwestern Hunan, China. Journal of Natural Gas Science and Engineering 53, 284-300. lower Palaeozoic Cambrian Niutitang shale and Silurian Longmaxi shale in the upper Yangtze region are the two most favourable marine shales in south China. Great achievements on shale gas development and production have already been made in the Longmaxi shale in southeastern Sichuan (SES). However, to date, economic shale gas potential has not been proved in northwestern Hunan (NWH), which is still a virgin area for shale gas exploration. Based on detailed outcrop investigation, laboratory testing and numerical simulation, the shale gas potential of Niutitang shale were evaluated in this work. Comparisons were also made through vertically diachroneity contrasting with the Longmaxi shale in the NWH area and horizontally isochronic contrasting with Niutitang shale in the SES area. Through analysing the evolution of the palaeoenvironment and palaeotectonics of the period from Niutitang to Longmaxi, it was found that: (1) the NWH Niutitang shale was developed in the hydrothermal continental shelf paleoenvironment, which provided a favourable environment for shale deposition, so the thicker and higher total organic carbon (TOC) shale was largely developed during this time; (2) By the influence of hydrothermal igneous leaching, the element Si formed quartz, which improved the brittleness of the Niutitang shale; (3) Induced by intense tectonic movement, natural fractures were highly developed in the Niutitang shale, which improved the reservoir connectivity; and (4) By comprehensively considering the TOC, reservoir property, and gas retention conditions, the Niutitang shale is a promising target for shale gas development in this area. The results from this work warrant further exploration work in the Niutitang shale in the NWH area.Wang, A.-j., Ye, X., Xu, X.-h., Yin, X.-j., Xu, Y.-h., 2018. Settling flux and origin of particulate organic carbon in a macro-tidal semi-enclosed embayment: Luoyuan Bay, Southeast China coast. Estuarine, Coastal and Shelf Science 206, 38-48. embayments play a vital role in the global carbon cycle either as sources of organic matter to open sea or as carbon sinks due to the accumulation of organic matter in sediments. This paper describes a study of Luoyuan Bay, a typical semi-enclosed embayment with a total area of approximately 227?km2 in a strong tidal environment. The analysed results indicate that the particulate organic carbon (POC) concentration in suspended particulate matter (SPM) varies from 0.57?mg/L to 1.33?mg/L at the bottom layer (0.5?MAB, meters above bed) and from 0.54?mg/L to 1.25?mg/L at the surface layer (0.5?MBS, meters below surface). The δ13C‰ ranges from??25.52‰ to??23.54‰ and exhibits different variations at the surface and bottom layers in spring and neap tides. The POC content in deposited particulate matter (DPM) varies from 0.62% to 2.95%, increasing from spring to neap tide, and the δ13C and C/N molar ratio are??25.29‰?～??21.41‰ and 4.18–8.53, respectively. The settling fluxes of POC obtained by sediment trap decrease from 2.25?g/m2·tide during the spring tide to 0.55?g/m2·tide during the neap tide with a mean value of 1.41?g/m2·tide during the observation, whereas the settling flux of SPM decreases from 456.76?g/m2·tide during the spring tide to 37.12?g/m2·tide during the neap tide. Combining the δ13C and C/N molar ratio, three end-members are recognized, i.e., freshwater algae and phytoplankton, marine algae and phytoplankton, and kelp-derived detritus. The mean contribution to POC from these three sources is 57.2%, 31.8% and 11.0% in SPM, and 39.9%, 35.0% and 25.1% in DPM, respectively. The POC from freshwater algae, phytoplankton and kelp-derived detritus is controlled by sediment dynamic processes.Wang, C., Liu, P., Wang, F., Atadurdyyev, B., Ovluyagulyyev, M., 2018. Experimental study on effects of CO2 and improving oil recovery for CO2 assisted SAGD in super-heavy-oil reservoirs. Journal of Petroleum Science and Engineering 165, 1073-1080. developing heavy-oil reservoirs using steam-assisted gravity drainage (SAGD) technology, CO2 is often used to reduce the viscosity of heavy oil and the heat loss of the steam chamber, thereby enhancing oil recovery. The limitation of experimental apparatuses, results in a maximum temperature of the reaction kettle of no more than 150?°C. Thus, the solubility of CO2 in super-heavy oil and its impact on decreasing viscosity beyond 150?°C requires further discussion. Considering these issues, a high-temperature-resistant heavy-oil mixing apparatus was designed to measure the solubility of CO2 in super-heavy oil and the relative density and viscosity of super-heavy oil under high temperatures and pressures. Core flooding experiments under 200?°C were conducted to explore the effects of CO2 on oil displacement efficiency. The results indicated that solubility of CO2 became significantly lower at 200?°C, when the viscosity and relative density of super-heavy oil decreased as pressure increased. The viscosity of super-heavy oil saturated with CO2 decreased by 71.2%, and relative density decreased by 10.1% at 200?°C compared to those of degassed crude. At temperatures of 120?°C, 150?°C and 200?°C, the ultimate displacement efficiency of super-heavy oil increased by 6.6%, 19.2% and 21.4%, respectively, compared to a temperature of 60?°C. At pressures of 1.0?MPa, 2.0?MPa and 4.0?MPa, the ultimate displacement efficiency (46.7%) of super-heavy oil increased by 5.2%, 4.0% and 5.9%, respectively, compared to a pressure of 0.5?MPa. The experiments showed that CO2 injection can effectively reduce the relative density and viscosity of super-heavy oil and improve oil recovery under high temperatures and pressures. CO2 has good potential to improve SAGD efficiency in developing super-heavy-oil reservoirs.Wang, D., Lv, R., Wei, J., Zhang, P., Yu, C., Yao, B., 2018. An experimental study of the anisotropic permeability rule of coal containing gas. Journal of Natural Gas Science and Engineering 53, 67-73. examine the characteristics of the anisotropic seepage of the coal containing gas, a study of the anisotropic seepage rule of the coal containing gas was carried out based on the tri-axial seepage experimental system with raw coal samples. The calculation method determined the principal value and the azimuth of the anisotropic permeability of the coal containing gas. Also, the permeability anisotropic ratio of the coal containing gas was defined. The permeability anisotropic dynamic variation rule and the phenomenon of the change of the dominant flow direction of the coal containing gas were thoroughly analyzed. The results showed that the flow of the methane in the coal had very obvious characteristics of anisotropy. The calculation method of anisotropy permeability of the coal containing gas proposed in this study was found to be simple and effective. The coal containing gas displayed strong stress-sensitivity. The variation rule between the permeability of the methane in the coal and the effective stress was determined to be in accordance with the negative exponential function. The change of the permeability anisotropy of the gases in the coal with effective stress showed an obvious dynamic change law of development, and changes were observed in the dominant flow direction of the gas in the coal.Wang, D., Wang, C., Li, C., Liu, C., Lu, H., Wu, N., Hu, G., Liu, L., Meng, Q., 2018. Effect of gas hydrate formation and decomposition on flow properties of fine-grained quartz sand sediments using X-ray CT based pore network model simulation. Fuel 226, 516-526. are performed to study the closed-loop effect of gas hydrate formation and decomposition on the flow properties of a fine-grained quartz sand specimen. The high resolution X-ray CT images of the test specimen at different experimental stages are acquired. In order to elucidate the changes in pore structure of the test specimen, topologically representative pore networks are established. The evolution of the flow properties during gas hydrate formation and decomposition is further evaluated. The results show that, gas hydrates occupancy in pore space exhibit different modes; they grow mainly as the grain-cementing mode except some intermediate stages, where pore-filling or load-bearing hydrates are observed. It is also found that the formation and decomposition of gas hydrates can cause the pore structure and flow properties changed. Increase of gas hydrate saturation results in a sharp decline in water relative permeability, larger irreducible water saturation and smaller gas-water percolation zone, while gas relative permeability does not exhibit obvious changing law. The decomposition of gas hydrates will exert a greater influence on the flow properties described above than gas hydrate formation does. The increase in frequency percentage of 10–20?μm pores within the fine-grained test specimen after experiments might be caused by gas hydrate decomposition induced damage of pore structure.Wang, J., Axia, E., Xu, Y., Wang, G., Zhou, L., Jia, Y., Chen, Z., Li, J., 2018. Temperature effect on abundance and distribution of leaf wax n-alkanes across a temperature gradient along the 400?mm isohyet in China. Organic Geochemistry 120, 31-41. chain n-alkanes are plant wax biomarkers that are widely used in paleoenvironmental reconstructions. Temperature is an important influence on the composition of leaf wax n-alkanes. However, to date, understanding of changes in the abundance and distribution of leaf wax n-alkanes with temperature remains unclear. The main reason is that the interference of precipitation on leaf wax n-alkanes has not been effectively removed in most investigations of natural ecosystems. We sampled 357 plants across a temperature gradient along an isohyet in China to minimize the influence of precipitation and evaluate the effect of temperature on the abundance and distribution of leaf wax n-alkanes. Most plant functional groups showed similar distributions in total n-alkane concentration (∑alk), carbon preference index (CPI) and average chain length (ACL). CPI values were not sensitive to temperature change. ∑alk values were negatively correlated with summer mean temperature (TJJA, June to August) for most plant functional groups. ACL values were always positively related to temperature, especially TJJA. However, large variability in ∑alk and ACL occurred within plants from the same site. Therefore, this study suggests that ∑alk and ACL can indicate relative environmental temperature, but they should not be used as quantitative proxies of paleo-temperature.Wang, J., Gao, Y.W., Jin, Z., Wang, C.J., Liu, C.H., Zhuang, Y., Wei, Y.Z., Sha, T., Xu, Q.S., Liu, X.N., Luo, Y.J., Sun, S.S., Zhang, Z.Z., 2018. Research on paraffin removal and prevention by Bacillus spp. in high-salinity reservoirs. Petroleum Science and Technology 36, 889-897. in paraffin deposition occur frequently in oil exploitation. Considering the problem that some paraffin removal and prevention strains cannot grow in high-salinity reservoirs, we domesticated four salt-tolerant laboratory bacterial strains. Crude oil emulsification effect, paraffin removal rate, and paraffin prevention rate of the strains were evaluated. KB and JH-A strains exhibited good paraffin removal and prevention effects, with paraffin removal rates of 51.82% and 81.56%; and 51.82% and 80.90%, respectively. Gas chromatography mass spectrometry analysis of paraffin components before and after biodegradation was performed on KB and JH-A strains. Results showed that relative contents of n-alkanes between C15-C23 and C27-C30 evidently decreased, indicating their good biodegradation. This technique provides a new method for practical application of paraffin removal and prevention in high-salinity reservoirs.Wang, J., Wu, S., Kong, X., Li, Q., Wang, J., Ding, R., 2018. Geophysical characterization of a fine-grained gas hydrate reservoir in the Shenhu area, northern South China Sea: Integration of seismic data and downhole logs. Marine and Petroleum Geology 92, 895-903. concentrated gas hydrate deposits in fine-grained sediment are proved to be eligible for exploitation with the current technology. Nevertheless, new insights and more understandings of the accumulation of gas hydrate and characterization of hydrate reservoir in fine-grained sediment are required, which can facilitate the commercial production of gas hydrate in the future. Combining seismic data and downhole logs, here we investigate a fine-grained gas hydrate reservoir in the Shenhu area, northern South China Sea (SCS). Gas hydrate with saturations of 10–45% occurs in fine-grained sediment. Besides the typical bottom-simulating reflectors (BSRs) and high amplitude reflection below BSR, a high amplitude positive reflector (referred to as the top of gas hydrate reservoir reflector; TGHR) exists at the top of high concentrated fine-grained gas hydrate reservoir. According to the result of acoustic impedance inversion, the TGHR is considered to represent a transitional zone from the overlying water-saturated sediment to the underlying high concentrated gas hydrate occurrence zone (GHOZ). Discontinuous BSRs beneath the traditional BSRs are also discovered in the study area, which are interpreted as the seismic evidence of the SII gas hydrate. In the Shenhu area, fluid flow features (such as chimney structures and faults) are found on the ridges where gas hydrate occurs, indicating that gas migration plays a critical role in the formation of gas hydrate in the fine-grained sediment. Our results provide valuable geophysical indications for detecting the presence of gas hydrate in fine-grained sediments.Wang, J., Yu, H., Song, X., Zhu, K., 2018. The influence of fatty acid supply and aldehyde reductase deletion on cyanobacteria alkane generating pathway in Escherichia coli. Journal of Industrial Microbiology & Biotechnology 45, 329-334. alkane synthetic pathway has been heterologously constructed in many microbial hosts. It is by far the most studied and reliable alkane generating pathway. Aldehyde deformylating oxygenase (i.e., ADO, key enzyme in this pathway) obtained from different cyanobacteria species showed diverse catalytic abilities. This work indicated that single aldehyde reductase deletions were beneficial to Nostoc punctiforme ADO-depended alkane production in Escherichia coli even better than double deletions. Fatty acid metabolism regulator (FadR) overexpression and low temperature increased C18:1 fatty acid supply, and in turn stimulated C18:1-derived heptadecene production, suggesting that supplying ADO with preferred substrate was important to overall alkane yield improvement. Using combinational methods, 1?g/L alkane was obtained in fed-batch fermentation with heptadecene accounting for nearly 84% of total alkane.Wang, J., Zhang, S., 2018. Pore structure differences of the extra-low permeability sandstone reservoirs and the causes of low resistivity oil layers: A case study of Block Yanwumao in the middle of Ordos Basin, NW China. Petroleum Exploration and Development 45, 273-280. influence of pore structure difference on rock electrical characteristics of reservoir and oil reservoir was analyzed taking Triassic Chang 6 reservoir in Block Yanwumao in the middle of Ordos Basin as an example. The relationship between the pore structure difference and the low resistivity oil layer was revealed and demonstrated through core observation, lab experiments, geological research, well log interpretation and trial production etc. The results show that there were two kinds of oil layers in Chang 6 oil layer set, normal oil layer and low resistivity oil layer in the region, corresponding to two types of pore structures, pore type mono-medium and micro-fracture?pore type double-medium; the development of micro-fracture changed greatly the micro-pore structure of the reservoir, and the pore structure difference had an important influence on the rock electrical characteristics of the extra-low permeability sandstone reservoir and oil reservoir; the normal oil layers had obvious characteristics of pore-type mono-medium, and were concentrated in Chang 61, Chang 622 and Chang 623; the low resistivity oil layers had obvious characteristics of micro-fracture?pore type double-medium, which were mainly distributed in Chang 621 and Chang 63. The mud filtrate penetrated deep into the oil layers along the micro-cracks, leading to sharp reduction of resistivity, and thus low resistivity of the oil layer; the low resistivity oil layers had better storage capacity and higher productivity than the normal oil layers.Wang, J.P., Matthews, M.L., Williams, C.M., Shi, R., Yang, C., Tunlaya-Anukit, S., Chen, H.-C., Li, Q., Liu, J., Lin, C.-Y., Naik, P., Sun, Y.-H., Loziuk, P.L., Yeh, T.-F., Kim, H., Gjersing, E., Shollenberger, T., Shuford, C.M., Song, J., Miller, Z., Huang, Y.-Y., Edmunds, C.W., Liu, B., Sun, Y., Lin, Y.-C.J., Li, W., Chen, H., Peszlen, I., Ducoste, J.J., Ralph, J., Chang, H.-M., Muddiman, D.C., Davis, M.F., Smith, C., Isik, F., Sederoff, R., Chiang, V.L., 2018. Improving wood properties for wood utilization through multi-omics integration in lignin biosynthesis. Nature Communications 9, Article 1579. multi-omics quantitative integrative analysis of lignin biosynthesis can advance the strategic engineering of wood for timber, pulp, and biofuels. Lignin is polymerized from three monomers (monolignols) produced by a grid-like pathway. The pathway in wood formation of Populus trichocarpa has at least 21 genes, encoding enzymes that mediate 37 reactions on 24 metabolites, leading to lignin and affecting wood properties. We perturb these 21 pathway genes and integrate transcriptomic, proteomic, fluxomic and phenomic data from 221 lines selected from ~2000 transgenics (6-month-old). The integrative analysis estimates how changing expression of pathway gene or gene combination affects protein abundance, metabolic-flux, metabolite concentrations, and 25 wood traits, including lignin, tree-growth, density, strength, and saccharification. The analysis then predicts improvements in any of these 25 traits individually or in combinations, through engineering expression of specific monolignol genes. The analysis may lead to greater understanding of other pathways for improved growth and adaptation.Wang, K., Yan, W., Deng, J., Tian, H., Li, W., Wang, Y., Wang, L., Ye, S., 2018. Experimental study on H2S and CO2 generation capacities of the Bohai bay heavy oil. Journal of Petroleum Science and Engineering 167, 241-248. recovery is a conventional technology for heavy oil development. During thermal oil recovery the reservoir could generate H2S and CO2. They will potentially threat the safety of downhole tubing regarding the sweet or sour corrosion. In some Bohai heavy oil fields CO2 and H2S under thermal recovery conditions lead to some corrosion problems of the tubing and equipment. Therefore, to determine the corrosive gas generation capacity is crucial for anti-corrosion design of downhole tubing and casing. Heavy oil samples from Bohai, China were experimentally studied for their pyrolysis characteristics using high-temperature-high-pressure autoclaves. The gases were collected when autoclaves cooled down to the in situ formation temperature. Effects of temperature, water chemistry and core mineral on corrosive gas generation were investigated. The results show that total pressure increase significantly when temperature reached 250°C-280?°C under the single heavy oil condition. The additional water facilitates the reaction process, after more SO42? added in the mimic formation water, higher H2S content is obtained. Under the condition of multiphase of oil, formation water and cores, both of the H2S and CO2 content increase obviously, and the cores' effect on CO2 is greater than H2S. Anti-corrosion design usually concerns only the highest corrosive gas concentration without further analysis. The highest concentration does not always correspond to the best corrosive gases generation capacities of heavy oil. Comprehensive analysis of both the total pressure of reaction process and the quality of the reaction heavy oil is carried out, then the corrosive gases volume per unit mass of heavy oil is calculated. These can determine the strongest corrosive formation environment and the maximum gases generation capacities of heavy oil.Wang, K., Zou, L., Lu, X., Mou, X., 2018. Organic carbon source and salinity shape sediment bacterial composition in two China marginal seas and their major tributaries. Science of The Total Environment 633, 1510-1517. sea sediments receive organic substrates of different origins, but whether and to what extent sediment microbial communities are reflective of the different sources of organic substrates remain unclear. To address these questions, sediment samples were collected in two connected China marginal seas, i.e., Bohai Sea and Yellow Sea, and their two major tributaries (Yellow River and Liao River). Sediment bacterial community composition (BCC) was examined using 16S rRNA gene pyrosequencing. In addition, physicochemical variables that describe environmental conditions and sediment features were measured. Our results revealed that BCCs changed with salinity and organic carbon (OC) content. Members of Gaiellaceae and Comamonadaceae showed a rapid decrease as salinity and phytoplankton-derived OC increased, while Piscirickettsiaceae and Desulfobulbaceae exhibited an opposite distribution pattern. Differences of riverine vs. marginal sea sediment BCCs could be mostly explained by salinity. However, within the marginal seas, sediment BCC variations were mainly explained by OC-related variables, including terrestrial-derived fatty acids (Terr_FA), phytoplankton-derived polyunsaturated fatty acids (Phyto_PUFA), stable carbon isotopes (δ13C), and carbon to nitrogen ratio (C/N). In addition to environmental variables, network analysis suggested that interactions among individual bacterial taxa might be important in shaping sediment BCCs in the studied areas.Wang, P., Peng, S., He, T., 2018. A novel approach to total organic carbon content prediction in shale gas reservoirs with well logs data, Tonghua Basin, China. Journal of Natural Gas Science and Engineering 55, 1-15. a geochemical parameter for characterizing source rock in shale gas reservoirs, estimation of total organic carbon (TOC) is a main task of geophysical and geochemical studies. TOC can be used to evaluate the hydrocarbon generation potential of source rocks. Artificial intelligence (AI) methods have been proposed recently to obtain TOC from well logs. This avoids expensive and time-consuming core analysis of geochemical experiments. However, the optimal combination (selected) of logs should be determined to get the highest accuracy TOC. We used a well-trained least square support vector machine model to select appropriate well log inputs for intelligent model based on mean impact values. We used a conventional 9 logs obtained from a shale gas well in Tonghua Basin, China, to test our method. The results were compared with 215 TOC values from core analysis. In addition, we tested three AI of models, including artificial neural network based on backpropagation algorithm (ANN-BP), least square support vector machine (LSSVM), and particle swarm optimization-least square support vector machine (PSO-LSSVM). For these three models, both selected logs and all logs are used for comparison. The TOC results, obtained from different calculations, showed that selected logs significantly improved the TOC accuracy in each AI model. By comparing different AI model, we found that PSO-LSSVM model outperforms the other two models. The TOC obtained from the PSO-LSSVM can benchmark with core analysis results.Wang, Q., Cui, D., Pan, S., Wang, Z., Liu, Q., Liu, B., 2018. Compositional characterization of neutral fractions in <300?°C distillates of six shale oils using extrography followed by GC-TOF/MS analysis. Fuel 224, 610-618. neutral fractions of <300?°C fractions of six Chinese shale oils obtained from different locations of Huadian, Wangqing, Fushun, Longkou, Maoming and Yaojie were eluted to six sub-fractions using extrography method. The compositions of sub-fractions were determined using gas chromatography-time of flight mass spectrometer (GC-TOF/MS). The results showed that F1 sub-fractions contained aliphatic hydrocarbons, such as alkanes, alkenes and cycloalkanes. In addition, HD F1 sub-fraction had the highest content of aliphatic hydrocarbons. The F2 sub-fractions contained aromatic hydrocarbons with 1–4-ring. Furthermore, a small amount of heteroatom compounds with aromatic rings (such as, dibenzofurans and carbazols) were also detected. The F3 sub-fractions contained aliphatic ketones and aliphatic nitriles ranging from C7-C25 and C9-C24, respectively. The F4 sub-fractions contained aliphatic ketones. However, the aliphatic ketones in F3 sub-fractions were 4-, 5-, 6-, 7- and 9-ketones, whereas those in F4 sub-fractions were all 2-ketones. The F5 sub-fractions contained nine kinds of compounds. Moreover, 2,5-hexanedione was dominant in all the samples except for MM F5 sub-fraction, whereas only two compounds were detected in MM F5 sub-fraction. Moreover, the F6 sub-fractions with less than 1?wt% in neutral fractions contained the unresolved complex matter (UCM), which cannot be eluted through gas chromatography (GC). Compared with the distribution of compounds in sub-fractions, the compounds of different samples consisted of similar species and slightly different contents. It indicates that the formation of compounds in the neutral fraction follows the same reaction pathways during kerogen pyrolysis.Wang, R., Peng, F., Song, K., Feng, G., Guo, Z., 2018. Molecular dynamics study of interfacial properties in CO2 enhanced oil recovery. Fluid Phase Equilibria 467, 25-32. enhanced oil recovery (EOR) is a promising technique for carbon capture, utilization and storage (CCUS). Owing to the abundant distribution of nanostructure in unconventional oil reservoirs, the investigation on the interfacial properties of the CO2 and oil system in nanopores is still lacking as well as the corresponding mechanism of displacement of oil by injecting CO2 in CO2 EOR. In this study, we coupled CO2 and n-decane force fields in molecular dynamics (MD) simulations by modifying Lorentz-Berthelot combination rules to calculate key physical properties of CO2+n-decane system more accurately. The phase equilibrium and interfacial properties of CO2+n-decane binary system were studied under different pressures. Then we explored the interfacial properties of CO2+n-decane mixture in α-quartz nanopores and found that the adsorption of CO2 is stronger than n-decane, which is beneficial for displacing n-decane from the pore surface and then enhancing oil recovery. An increase in the diffusion of n-decane was observed with the increase of injected CO2, while when excess CO2 was injected, the diffusivity of CO2 and n-decane in nanopore both decreased. The underlying mechanisms of these phenomena were understood by the structure and diffusive properties in bulk and α-quartz nanopores.Wang, S., Sun, X., Yuan, Q., 2018. Strategies for enhancing microbial tolerance to inhibitors for biofuel production: A review. Bioresource Technology 258, 302-309. lignocellulosic biomass for the production of renewable biofuel provides a sustainable and promising solution to the crisis of energy and environment. However, the processes of biomass pretreatment and biofuel fermentation bring a variety of inhibitors to microbial strains. These inhibitors repress microbial growth, decrease biofuel yields and increase fermentation costs. The production of biofuels from renewable lignocellulosic biomass relies on the development of tolerant and robust microbial strains. In recent years, the advancement of tolerance engineering and evolutionary engineering provides powerful platform for obtaining host strains with desired tolerance for further metabolic engineering of biofuel pathways. In this review, we summarized the inhibitors derived from biomass pretreatment and biofuel fermentation, the mechanisms of inhibitor toxicity, and the strategies for enhancing microbial tolerance.Wang, T., Wang, J., Yang, W., Kalitaani, S., Deng, Z., 2018. A novel air flooding technology for light crude oil reservoirs applied under reservoir conditions. Energy & Fuels 32, 4942-4950. novel air flooding technology based on catalyst-activated low-temperature oxidation (CLTO) has been researched by static and dynamic oxidation experiments and can be applied in light crude oil reservoirs under reservoir conditions to improve the safety and oil recovery of air flooding. The catalytic effect of additives on the oxidation behavior of three crude oils was researched. The changes in oil recovery, oxygen distribution, and oil characteristics caused by additives were researched by dynamic oxidation experiments, and the influences of crude oil types, additive injection pattern, injection volume, and injection time on the catalytic effect were also researched. The results show that metallic additives can improve the oxygen consumption capacity of crude oils. Furthermore, the addition of additives can delay the oxygen breakthrough time and reduce the oxygen content in the gas produced. During the catalytic air flooding, the oxygen injected reacts mainly with the residual oil near the injection wells, and the influence of CLTO on the properties of oil produced from light oil reservoirs is minor. The key point to guarantee the success of catalytic air flooding is to select the optimal catalyst for the reservoir oil. The preferred catalyst injection pattern is catalyst alternating air injection, and the recommended catalyst injection volume is 0.03–0.05 PV. Catalytic air flooding technology can improve the safety and widen the application of air flooding technology.Wang, T., Zhang, Y., Li, L., Yang, Z., Liu, Y., Fang, J., Dai, C., You, Q., 2018. Experimental study on pressure-decreasing performance and mechanism of nanoparticles in low permeability reservoir. Journal of Petroleum Science and Engineering 166, 693-703. use of nanoparticles for low-permeability reservoirs is a cutting-edge frontier technology in oil field development. By investigating the optimization of nanoparticles and the implantation scheme, we have achieved the goal of using nanoparticles efficiently and economically. In this study, we tested the basic properties of nanoparticles Finally, we selected an ideal nanoparticle to conduct further experiments and innovatively applied micro-tubes to simulate the core pores by simplifying the model structure. The effects of the nanoparticle injection rate and pore size on the pressure reduction were studied and verified by core-flooding experiments. The experimental results showed that the pressure-decreasing ability of the nanoparticles exhibited greatly pressure-decreasing efficiency, initially an increasing trend and followed by a decrease with an increase in the injection rate. The hydrophobic nanoparticles adsorb on the surface of the rock pores, which fills the rough surfaces in the rock pores and forms a stable hydrophobic surface film. This nanofilm improves the roughness of the rock pore surface and replaces the hydration layer formed by the injection of water so that the surface of the pore wall is transformed from a hydrophilic to a hydrophobic state, which improves the core wettability, avoids hydration expansion, reduces interfacial tension, improves the pore diameter and results in a decrease in the flow resistance. This study has significant impact of nanoparticles on effective and economic development in low permeability reservoirs, which could solve to high injection pressure problem during water injecting to supplement energy.Wang, W., Dong, M., Song, C., Cai, X., Liu, Y., Liu, Z., Tian, S., 2018. Structural information of asphaltenes derived from petroleum vacuum residue and its hydrotreated product obtained by FT-ICR mass spectrometry with narrow ion isolation windows. Fuel 227, 111-117. asphaltene is a complex natural organic mixture which plays a crucial role in the refining processes. In this work, asphaltenes derived from petroleum vacuum residue and its hydrotreated product were characterized by high-field Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Tandem mass spectra with narrow ion isolation window were realized by increasing the value of collision RF amplitude. Tandem mass spectra with 3?Da and 1?Da isolation windows were compared, which demonstrated the advantages of applying narrow isolation window of 1?Da. The tandem mass spectra of asphaltenes were simplified due to the narrow isolation window. Moreover, a better correlation between the parent and fragment ions obtained by narrow isolation window of 1?Da was suggested by moving the isolation window. Finally, aromatic hydrocarbons with more naphthenic rings were suggested for the molecular structures of the processed asphaltene according to the results.Wang, W., Wang, Y., An, C., Ruan, Q., Duan, F., Li, W., Dong, W., 2018. Human diet and subsistence strategies from the Late Bronze Age to historic times at Goukou, Xinjiang, NW China. The Holocene 28, 640-650. diet and subsistence strategies from the Late Bronze Age to historic times (1600 BC–AD 900) are explored for the Goukou site, Xinjiang, using human and other animal stable isotope analyses alongside radiocarbon dating and preliminary archaeobotanical studies. Our results show that during the Late Bronze Age, human bones have mean δ13C and δ15N values of ?14‰ and 12.9‰, respectively; during the Early Iron Age, they have mean δ13C and δ15N values of ?16.4‰ and 10.1‰, respectively; from the time of the Warring States to the Han Dynasty, the mean δ13C and δ15N values are ?14.8‰ and 12.2‰, respectively; and from the Jin–Tang Dynasties, human bones have mean δ13C and δ15N values of ?15.5‰ and 11.5‰, respectively. Generally, people mainly consumed animal products and possibly milk/dairy products as well as various cereals including millet and wheat/barley. Little dietary variance occurred over time. Inferred subsistence strategies in Goukou include herding, farming, and hunting. There is evidence that cultural exchange between East and West as well as local environmental conditions contributed to the formation and development of multiple economic practices in Goukou.Wang, X., Liu, S.-A., Wang, Z., Chen, D., Zhang, L., 2018. Zinc and strontium isotope evidence for climate cooling and constraints on the Frasnian-Famennian (~372?Ma) mass extinction. Palaeogeography, Palaeoclimatology, Palaeoecology 498, 68-82. Frasnian-Famennian (F-F) mass extinction is one of the “Big Five” biotic crises during the Phanerozoic, whereas the cause of this catastrophic event still remains debated. Here we present for the first time high-resolution Zn and Sr isotope data obtained by a sequential leaching procedure for carbonate rocks across the F-F boundary from the Fuhe section in South China. Both δ66Zn and 87Sr/86Sr values rapidly increase in the Lower and Upper Kellwasser Horizons and Palmatolepis delicatula platys to P. minuta minuta conodont zones, and the positive isotope shifts are exactly located in the same horizons characterized by low ?13C values (equivalent to low atmospheric PCO2 level, reflecting climate cooling) and sea-level fall stages. The strong temporal coupling of δ66Zn values raise with elevated 87Sr/86Sr ratios is most likely to have been caused by input of isotopically heavy Zn and radiogenic Sr from carbonate-dominated weathering, and/or uptake of isotopically light Zn into primary producers during climate cooling. Climate cooling could cause relative sea-level falls resulting in widespread exposure of carbonate platform, enhance carbonate influx proportion through differential weathering of carbonate and silicate rocks, and cause greater productivity by promoting oceanic thermohaline circulation and enhancing upwelling of bio-limiting nutrients. All of these processes would have contributed to the positive shifts of δ66Zn as observed. This proposed scenario is in accordance with the fact that the F-F mass extinction was almost limited to the shallow-water tropical stenothermal faunas, whereas the high latitude and deep-water faunas were less affected. Our data support and represent the composite effect of a series of events linked to climate cooling which may have induced this catastrophic event.Wang, X., Mou, C., Wang, Q., Zhou, K., Liang, W., Ge, X., Chen, X., 2018. Recomment on the study of lithofacies palaeogeography as a guide for geology survey of shale gas. Acta Sedimentologica Sinica 36, 215-231. basic geological parameters, including total organic carbon conten (TOC) and type, thermal evolution of organic matter(Ro) thickness of hydrocarbon source rocks, mineral composition and content, reservoir characteristics, which all controlled by sedimentary facies, are the main elements to evaluate the enrichment of shale gas in regional geology survey stage. On the basis of the detailed study of sedimentary facies, by mapping the lithofacies palaeogeography, distribution of the fine-grained sedimentary rocks which are rich in organic matter can be figured out. So, the lithofacies paleogeography controls the developmental characteristics of the shale gas. Using the basic geological parameters, the shale gas favorable areas in southern Sichuan Basin and its peripheral region were preliminarily evaluated. The black rocks of shallow shelf facies in Longmaxi Formation of Silurian, as long as being up into middle diagenetic stage, would be able to be shale gas reservoirs in southern Sichuan Basin and its periphery. On the basis of our previous study, through analyzing the shale gas geologic feature of Longmaxi Formation in southern Sichuan Basin and its periphery, the point of view is further demonstrated, that the study of sedimentary facies or lithofacies palaeogeography is the key and foundation of shale gas geology survey and evaluation.Wang, Y., Hua, L., Li, Q., Jiang, J., Hou, K., Wu, C., Li, H., 2018. Direct detection of small n-alkanes at sub-ppbv level by photoelectron-induced O2+ cation chemical ionization mass spectrometry at kPa pressure. Analytical Chemistry 90, 5398-5404. mass spectrometric measurements of saturated hydrocarbons, especially small n-alkanes, remains a great challenge because of low basicity and lack of ionizable functional groups. In this work, a novel high-pressure photoelectron-induced O2+ cation chemical ionization source (HPPI-OCI) at kPa based on a 10.6 eV krypton lamp was developed for a time-of-flight mass spectrometer (TOFMS). High-intensity O2+ reactant ions were generated by photoelectron ionization of air molecules in the double electric field ionization region. The quasi-molecular ions, [M–H]+, of C3–C6 n-alkanes, gradually dominated in the mass spectra when the ion source pressure was elevated from 88 to 1080 Pa, with more than 3 orders of magnitude improvement in signal intensity. As a result, the achieved limits of detection were lowered to 0.14, 0.11, 0.07, and 0.1 ppbv for propane, n-butane, n-pentane, and n-hexane, respectively. The performance of the HPPI-OCI TOFMS was first demonstrated by analysis of exhaled small n-alkanes from healthy smokers and nonsmokers. Then the concentration variations of exhaled small n-alkanes of four healthy volunteers were analyzed after alcohol consumption to explore the alcohol-hepatoxicity-related oxidative stress. In summary, this work provides new insights for controlling the O2+-participating chemical ionization by adjusting the ion source pressure and develops a novel direct mass spectrometric method for sensitive measurements of mall n-alkanes.Wang, Y., Xu, Y., Spencer, R.G.M., Zito, P., Kellerman, A., Podgorski, D., Xiao, W., Wei, D., Rashid, H., Yang, Y., 2018. Selective leaching of dissolved organic matter from alpine permafrost soils on the Qinghai‐Tibetan Plateau. Journal of Geophysical Research: Biogeosciences 123, 1005-1016. global temperature rise has caused significant thaw and degradation of permafrost soils on the Qinghai‐Tibetan Plateau (QTP). Leaching of organic matter from permafrost soils to aquatic systems is highly complex and difficult to reproduce in a laboratory setting. We collected samples from natural seeps of active and permafrost layers in an alpine swamp meadow on the QTP to shed light on the composition of mobilized dissolved organic matter (DOM) by combining optical measurements, ultrahigh‐resolution Fourier transform ion cyclotron resonance mass spectrometry, radiocarbon (14C), and solid‐state 13C nuclear magnetic resonance spectroscopy. Our results show that even though the active layer soils contain large amounts of proteins and carbohydrates, there is a selective release of aromatic components, whereas in the deep permafrost layer, carbohydrate and protein components are preferentially leached during the thawing process. Given these different chemical characteristics of mobilized DOM, we hypothesize that photomineralization contributes significantly to the loss of DOM that is leached from the seasonally thawed surface layer. However, with continued warming, biodegradation will become more important since biolabile materials such as protein and carbohydrate are preferentially released from deep‐layer permafrost soils. This transition in DOM leachate source and associated chemical composition has ramifications for downstream fluvial networks on the QTP particularly in terms of processing of carbon and associated fluxes.Wang, Y., Yang, R., Song, M., Lenhardt, N., Wang, X., Zhang, X., Yang, S., Wang, J., Cao, H., 2018. Characteristics, controls and geological models of hydrocarbon accumulation in the Carboniferous volcanic reservoirs of the Chunfeng Oilfield, Junggar Basin, northwestern China. Marine and Petroleum Geology 94, 65-79. Junggar Basin is one of the most important basins for hydrocarbon production in China. Within the basin, the Chunfeng Oilfield forms one of the most important oilfields of the area. Despite the significant work that has been done on the rocks of the oilfield so far, a detailed reservoir characterization and description of the hydrocarbon accumulation pattern was still missing. Therefore, an investigation had been initiated to fill this gap in our understanding of the hydrocarbon reservoirs of the Junggar Basin. The results of this study show that the tuff and andesitic lava lithofacies exhibit the highest reservoir potential in the area. Apart from the lithofacies, the results of this study show that tectonic (formation of fault systems) and diagenetic (formation of solution pores) effects, and the development of a weathering crust are crucial factors that control the quality of the petroleum reservoirs of the oilfield. In addition, two possible geological models of petroleum accumulation in isolated volcanic rocks and sandstone (IVRS) and connected volcanic rocks and sandstone (CVRS) are presented.Wang, Z., Tang, X., 2018. New insights from supercritical methane adsorption in coal: Gas resource estimation, thermodynamics, and engineering application. Energy & Fuels 32, 5001-5009. coal-bed methane (CBM) resource estimation becomes significant for CBM extraction through ground CBM wells and underground coal mines, and adsorbed gas accounts for more than 80% of the total CBM in place resource in subsurface coal seams. However, the CBM resource estimation presents many challenges, especially the inappropriate adsorbed gas estimation method and the oversimplified adsorption thermodynamics description. This work tackles both issues by utilizing a dual-site Langmuir model to describe supercritical methane adsorption behavior in anthracite and analyze the corresponding thermodynamic characteristics. The proposed model not only accurately describes measured adsorption isotherms under elevated pressures (up to 17 MPa) and temperatures (up to 352.55 K) and interprets all observed adsorption phenomena, but also can extrapolate the adsorbed gas content and the total gas content at subsurface conditions beyond test conditions. The estimated density of the adsorbed methane is found to be temperature and pressure dependent, which is higher than the gas density but lower than the liquid methane density. The isosteric enthalpy of adsorption for methane in coal shows adsorption uptake dependence and temperature dependence behavior. Using the classic simplified Clausius–Clapeyron equation overestimates the isosteric enthalpy of adsorption, which cannot reveal the associated temperature dependence behavior. Furthermore, the proposed method is applied for estimating deep CBM in place resource and understanding coal and gas outburst prediction technology by using the temperature measurement approach.Warrag, S.E.E., Pototzki, C., Rodriguez, N.R., van Sint Annaland, M., Kroon, M.C., Held, C., Sadowski, G., Peters, C.J., 2018. Oil desulfurization using deep eutectic solvents as sustainable and economical extractants via liquid-liquid extraction: Experimental and PC-SAFT predictions. Fluid Phase Equilibria 467, 33-44. reduction of the sulfur content in crude oil is of utmost importance in order to meet the stringent environmental regulations. Thiophene and its derivatives are considered key substances to be separated from the crude oil. In previous works, six deep eutectic solvents (DESs) based on tetraethylammonium chloride, tetrahexylammonium bromide and methyltriphenylphosphonium bromide as hydrogen bond acceptors (HBAs) and polyols (ethylene glycol and glycerol) as hydrogen bond donors (HBDs) were successfully applied for the extraction of thiophene from {n-alkane + thiophene} mixtures via liquid-liquid extraction. One of the objectives of this work was to study the effect of the aliphatic hydrocarbon type/length (e.g. n-hexane vs n-octane) on the extraction performance of the same DESs. Extraction performance was evaluated by the selectivity and the thiophene distribution coefficient. Based on new experimental data, higher selectivities and lower thiophene distribution coefficients were obtained when thiophene was extracted from n-octane instead of n-hexane. Another objective was to predict the phase behavior of the ternary systems {n-alkane + thiophene + DES} using Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT). The PC-SAFT “pseudo-pure component” approach was applied, in which a DES was considered as a pseudo-pure compound (not a mixture). The pure-component parameters of the DESs were obtained by fitting to liquid density data, which were measured at temperatures between 298.2 K and 323.2 K. Binary interaction parameters were fitted to experimental binary LLE data for the systems {n-alkane + DES} and {thiophene + DES} at 298.2 K and atmospheric pressure, while the LLE data of the ternary systems {n-alkane + thiophene + DES} were fully predicted. It was found that the distribution coefficients and selectivity of the ternary systems containing DESs could be qualitatively well predicted using this model.Watanabe, H., 2018. X-ray CT visualization of woody char intra-particle pore structure and its role on anisotropic evolution during char gasification. Energy & Fuels 32, 4248-4254. computed tomography (CT) was used to visualize the intra-particle structure of woody biomass and its chars, and impact of intra-particle structure on gasification characteristics was studied. The chars derived from ramin (hardwood) and Japanese cypress (softwood) were gasified under O2/Ar atmosphere. X-ray computed tomography (CT) was used for observation of intra-particle structure. As a result, X-ray CT well visualized relatively large pores over 10 ?m. The ramin chars had more large pores aligned along transverse direction than Japanese cypress chars, whereas pores aligned along grain direction were dominant in both chars. Although the gasification rate of both chars were similar, impact of the anisotropic intra-particle structure originated from nature of wood appeared in the evolution of particle shape during gasification controlled by an internal diffusion. This was because large pores acted as gas transport pathways inside the chars. The gasification progressed along transverse direction in the ramin chars, resulting in forming an ellipse shape, although the initial shape was cylinder. On the contrary, the gasification progressed along only grain direction and cylindrical shape was kept in the Japanese cypress chars. Wei, G., Wang, Z., Li, J., Yang, W., Xie, Z., 2017. Characteristics of source rocks, resource potential and exploration direction of Sinian-Cambrian in Sichuan Basin, China. Journal of Natural Gas Geoscience 2, 289-302. Anyue giant gas field was discovered in the Sinian-Cambrian Central Sichuan region of the Sichuan Basin in 2013, with geological reserves up to 1 × 1012m3, which is the first time for the exploration of natural gas paleo-reservoirs in the world. The gas source studies suggest that the Sinian natural gas is originated from the Sinian and Cambrian hydrocarbon source rocks, and the systematical study on the Sinian and Cambrian ancient source rocks has important scientific and practical significance for the global oil and gas geologic domain of the ancient stratum. Based on the drilling data and field profile observation of Sinian and Cambrian in Sichuan Basin, with adoption of the interpretation data of 28000 km-seismic and new drilling data, combined with geochemical analysis of source rocks of 2315 samples, this paper systematically studied the high quality hydrocarbon source rock center, where the source rocks are mainly distributed along the Mianzhu-Changning craton inner rift, with a accumulative thickness reaching 200–450 m, and 50–100 m for the thickness of source rocks in other areas. The hydrocarbon source rocks of the Sinian-Cambrian contributed about 56 %–63% of natural gas resources of the whole basin. Systematical evaluations have been conducted to the mudstone source rocks and their distribution in the III-section of Sinian Dengying Formation, where TOC value is ranging from 0.04% to 4.73%, with an average of 0.65%. The thickness of the source rocks in Central Sichuan region is ranging from 10 to 30 m. The oldest Sinian source rocks that can form large gas fields in China were systematically studied for the first time, and the total gas production intensity of the Sinian source rocks in the great Central Sichuan region is (15–28) × 108 m3/km2, where the gas source conditions for the formation of large gas fields are available. By using the genetic method and analogy method, the amount of natural gas resources of the Sinian-Cambrian in the basin are re-evaluated as (4.65–5.58) × 1012 m3, and the resources potential of natural gas is huge. The amount of natural gas resources in the Central Sichuan block accounts for about 66% of the total basin resources, which is the preferred selection for current exploration.Wei, G., Yang, W., Zhang, J., Xie, W., Zeng, F., Su, N., Jin, H., 2018. The pre-Sinian rift in central Sichuan Basin and its control on hydrocarbon accumulation in the overlying strata. Petroleum Exploration and Development 45, 193-203. on the latest seismic data, resistivity profile, outcrop evidence and logging data, the structural features of basement in Sichuan Basin and its control on the hydrocarbon accumulation in the Sinian-Cambrian strata was discussed. It was found that a NE striking pre-Sinian rift was developed across the whole basin. Controlled by a series of rift-parallel normal faults, horst-graben structures were developed inside the rift, large horst-graben structures and later activity of their boundary faults controlled the distribution of beach facies of the overlying strata. The horst-graben structures induced the formation of local highs of ancient landform and controlled the successive development of overlapped bioherm beach facies in long-term marine setting from the Sinian period to the Permian period, and as a result a widely distributed favorable sedimentary facies belt was developed. The pre-Sinian rift and later activities of related normal faults controlled the development of the grain beach and karst reservoirs and the deposition of high quality source rock, which form structural-lithologic traps. Through comprehensive evaluation, two large structural-lithologic composite trap favorable exploration areas in the south and north of the Gaoshiti-Moxi area, were selected.Wei, L., Schimmelmann, A., Mastalerz, M., Lahann, R.W., Sauer, P.E., Drobniak, A., Str?po?, D., Mango, F.D., 2018. Catalytic generation of methane at 60–100?°C and 0.1–300?MPa from source rocks containing kerogen Types I, II, and III. Geochimica et Cosmochimica Acta 231, 88-116. temperature (60 and 100?°C) and long-term (6 months to 5?years) heating of pre-evacuated and sterilized shales and coals containing kerogen Types I (Mahogany Shale), II (Mowry Shale and New Albany Shale), and III (Springfield Coal and Wilcox Lignite) with low initial maturities (vitrinite reflectance Ro 0.39–0.62%) demonstrates that catalytically generated hydrocarbons may explain the occurrence of some non-biogenic natural gas accumulations where insufficient thermal maturity contradicts the conventional thermal cracking paradigm. Extrapolation of the observed rate of catalytic methanogenesis in the laboratory suggests that significant amounts of sedimentary organic carbon can be converted to relatively dry natural gas over tens of thousands of years in sedimentary basins at temperatures as low as 60?°C.Our laboratory experiments utilized source rock (shale and coal) chips sealed in gold and Pyrex? glass tubes in the presence of hydrogen-isotopically contrasting waters. Parallel heating experiments applied hydrostatic pressures from 0.1 to 300?MPa. Control experiments constrained the influence of pre-existing and residual methane in closed pores of rock chips that was unrelated to newly generated methane.This study’s experimental methane yields at 60 and 100?°C are 5–11 orders of magnitude higher than the theoretically predicted yields from kinetic models of thermogenic methane generation, which strongly suggests a contribution of catalytic methanogenesis. Higher temperature, longer heating time, and lower hydrostatic pressure enhanced catalytic methanogenesis. No clear relationships were observed between kerogen type or total organic carbon content and methane yields via catalysis. Catalytic methanogenesis was strongest in Mowry Shale where methane yields at 60?°C amounted to ～2.5?μmol per gram of organic carbon after one year of hydrous heating at ambient pressure.In stark contrast to the earlier findings of hydrogen isotopic exchange between water and thermogenic methane in hydrous pyrolysis experiments above 300?°C, the hydrogen isotopic composition of added water exerted limited influence on the δ2H value of methane generated catalytically at low temperatures. We hypothesize that the catalytic sites responsible for methanogenesis are located in hydrophobic microenvironments with limited access to water. The δ13CCH4 values of methane generated catalytically at 60–100?°C range from ～?57.6 to ?41.4‰ and are thus similar to typical thermogenic methane (δ13CCH4 >?50‰) and microbially generated methane (<?55‰). Future studies need to evaluate the possibility that clumped isotope characteristics of catalytically generated methane can diagnose the low-temperature regime of catalytic methanogenesis. Furthermore, testing of freshly cored anoxic rocks is needed to determine whether the use of archived, oxygen-exposed rocks in geochemical maturation/catalysis studies introduces artifacts in experimental hydrocarbon yields.Wei, W., Zhu, X., He, M., Wang, M., Liu, X., 2018. Original sediment composition of the Lower Cretaceous lacustrine tight-oil mudstone and influences on diagenesis and organic matter content, the Erennaoer Sag in Erlian Basin, NE China. Marine and Petroleum Geology 94, 131-143. original sediment composition is of great value to providing an understanding of depositional environment and hydrocarbon-generation potential, but it is easily altered by diagenesis and difficult to recognize. In this study, we examine carbonate-rich tight-oil mudstones of the Lower Cretaceous Arshan Formation in the Erennaoer sag of the Erlian Basin as an example. Based on analyses of mineralogy, stable carbon and oxygen isotopes, and trace/rare earth elements, the original composition of the Arshan mudstones has been reconstructed. Results show that the original Arshan mudstone composition was mainly siliciclastic detritus, tuffaceous and clay matrix, which has a major impact on diagenesis and organic matter content. The erupted volcanic ashes were beneficial to the introduction of nutrients, an increase in biomass and an associated increase in to the preservation of organic matter, which has been suggested by an improvement of TOC of Arshan tuffaceous mudstones, with average contents of 2.82%. The volcanic ashes in the studied mudstones had also enhanced methanogensis during the shallow burial. Additionally, the early alteration products of authigenic minerals include analcime or zeolite, most of which is entirely altered to analcime and chlorite. The formation of major eogenetic carbonate cements include early dolomite and calcite, which were related to volcanic materials and methanogenesis at shallow depths.Welte, C.U., 2018. Revival of archaeal methane microbiology. mSystems 3, DOI: 10.1128/mSystems.00181-17. methane concentration in the Earth’s atmosphere is rising, and, as methane is a potent greenhouse gas, it contributes considerably to climate change. It is produced by methanogenic archaea that thrive in anoxic habitats and can be oxidized by methane-oxidizing bacteria or archaea. In this Perspective, recent innovations and discoveries in archaeal methane microbiology are discussed and a future outlook on how novel methane-metabolizing archaea might be cultivated is provided.Wen, X., Unger, V., Jurasinski, G., Koebsch, F., Horn, F., Rehder, G., Sachs, T., Zak, D., Lischeid, G., Knorr, K.H., B?ttcher, M., Winkel, M., Liebner, S., 2018. Predominance of methanogens over methanotrophs contributes to high methane emissions in rewetted fens. Biogeosciences Discussions 2018, 1-37. rewetting of drained peatlands alters peat geochemistry and often leads to sustained elevated methane emission. Although this methane is produced entirely by microbial activity, the distribution and abundance of methane-cycling microbes in rewetted peatlands, especially in fens, is rarely described. In this study, we compare the community composition and abundance of methane-cycling microbes in relation to peat porewater geochemistry in two rewetted fens in northeastern Germany, a coastal brackish fen and a freshwater riparian fen, with known high methane fluxes. We utilized 16S rDNA high-throughput sequencing and quantitative polymerase chain reaction on 16S rDNA, mcrA, and pmoA genes to determine microbial community composition and the abundance of total bacteria, methanogens, and methanotrophs. Electrical conductivity was more than three times higher in the coastal fen than in the riparian fen, averaging 5.3 and 1.5?mS?cm?1, respectively. Porewater concentrations of terminal electron acceptors varied within and among the fens. This was also reflected in similarly high intra- and inter-site variations of microbial community composition. Despite these differences in environmental conditions and electron acceptor availability, we found a low abundance of methanotrophs and a high abundance of methanogens, represented in particular by Methanosaetaceae, in both fens. This suggests that rapid re/establishment of methanogens and slow re/establishment of methanotrophs contributes to prolonged increased methane emissions following rewetting.Wenzel, J., Fiset, E., Batlle-Vilanova, P., Cabezas, A., Etchebehere, C., Balaguer, M.D., Colprim, J., Puig, S., 2018. Microbial community pathways for the production of volatile fatty acids from CO2 and electricity. Frontiers in Energy Research 6, 15. doi: 10.3389/fenrg.2018.00015. study aims at elucidating the metabolic pathways involved in the production of volatile fatty acids from CO2 and electricity. Two bioelectrochemical systems (BES) were fed with pure CO2 (cells A and B). The cathode potential was first poised at ?574 mV vs. standard hydrogen electrode (SHE) and then at ?756 mV vs. SHE in order to ensure the required reducing power. Despite applying similar operation conditions to both BES, they responded differently. A mixture of organic compounds (1.87 mM acetic acid, 2.30 mM formic acid, 0.43 mM propionic acid, 0.15 mM butyric acid, 0.55 mM valeric acid, and 0.62 mM ethanol) was produced in cell A while mainly 1.82 mM acetic acid and 0.23 mM propionic acid were produced in cell B. The microbial community analysis performed by 16S rRNA gene pyrosequencing showed a predominance of Clostridium sp. and Serratia sp. in cell A whereas Burkholderia sp. and Xanthobacter sp. predominated in cell B. The coexistence of three metabolic pathways involved in carbon fixation was predicted. Calvin cycle was predicted in both cells during the whole experiment while Wood-Ljungdahl and Arnon-Buchanan pathways predominated in the period with higher coulombic efficiency. Metabolic pathways which transform organic acids into anabolic intermediaries were also predicted, indicating the occurrence of complex trophic interactions. These results further complicate the understanding of these mixed culture microbial processes but also expand the expectation of compounds that could potentially be produced with this technology.Werner, J.P., Divine, D.V., Charpentier Ljungqvist, F., Nilsen, T., Francus, P., 2018. Spatio-temporal variability of Arctic summer temperatures over the past 2 millennia. Climate of the Past 14, 527-557. this article, the first spatially resolved and millennium-length summer (June–August) temperature reconstruction over the Arctic and sub-Arctic domain (north of 60°?N) is presented. It is based on a set of 44 annually dated temperature-sensitive proxy archives of various types from the revised PAGES2k database supplemented with six new recently updated proxy records. As a major advance, an extension of the Bayesian BARCAST climate field (CF) reconstruction technique provides a means to treat climate archives with dating uncertainties. This results not only in a more precise reconstruction but additionally enables joint probabilistic constraints to be imposed on the chronologies of the used archives. The new seasonal CF reconstruction for the Arctic region can be shown to be skilful for the majority of the terrestrial nodes. The decrease in the proxy data density back in time, however, limits the analyses in the spatial domain to the period after 750?CE, while the spatially averaged reconstruction covers the entire time interval of 1–2002?CE.The centennial to millennial evolution of the reconstructed temperature is in good agreement with a general pattern that was inferred in recent studies for the Arctic and its subregions. In particular, the reconstruction shows a pronounced Medieval Climate Anomaly (MCA; here ca. 920–1060?CE), which was characterised by a sequence of extremely warm decades over the whole domain. The medieval warming was followed by a gradual cooling into the Little Ice Age (LIA), with 1766–1865?CE as the longest centennial-scale cold period, culminating around 1811–1820?CE for most of the target region.In total over 600 independent realisations of the temperature CF were generated. As showcased for local and regional trends and temperature anomalies, operating in a probabilistic framework directly results in comprehensive uncertainty estimates, even for complex analyses. For the presented multi-scale trend analysis, for example, the spread in different paths across the reconstruction ensemble prevents a robust analysis of features at timescales shorter than ca. 30 years. For the spatial reconstruction, the benefit of using the spatially resolved reconstruction ensemble is demonstrated by focusing on the regional expression of the recent warming and the MCA. While our analysis shows that the peak MCA summer temperatures were as high as in the late 20th and early 21st centuries, the spatial coherence of extreme years over the last decades of the reconstruction (1980s onwards) seems unprecedented at least back until 750?CE. However, statistical testing could not provide conclusive support of the contemporary warming to exceed the peak of the MCA in terms of the pan-Arctic mean summer temperatures: the reconstruction cannot be extended reliably past 2002?CE due to lack of proxy data and thus the most recent warming is not captured.Wernisch, S., Afshinnia, F., Rajendiran, T., Pennathur, S., 2018. Probing the application range and selectivity of a differential mobility spectrometry–mass spectrometry platform for metabolomics. Analytical and Bioanalytical Chemistry 410, 2865-2877. applications of differential mobility spectrometry (DMS)–mass spectrometry (MS) have largely concentrated on targeted assays and the removal of isobaric or chemical interferences from the signals of a small number of analytes. In the work reported here, we systematically investigated the application range of a DMS-MS method for metabolomics using more than 800 authentic metabolite standards as the test set. The coverage achieved with the DMS-MS platform was comparable to that achieved with chromatographic methods. High orthogonality was observed between hydrophilic interaction liquid chromatography and the 2-propanol-mediated DMS separation, and previously observed similarities were confirmed for the DMS platform and reversed-phase liquid chromatography. We describe the chemical selectivity observed for selected subsets of the metabolite test set, such as lipids, amino acids, nucleotides, and organic acids. Furthermore, we rationalize the behavior and separation of isomeric aromatic acids, bile acids, and other metabolites.Wheeley, J.R., Jardine, P.E., Raine, R.J., Boomer, I., Smith, M.P., 2018. Paleoecologic and paleoceanographic interpretation of δ18O variability in Lower Ordovician conodont species. Geology 46, 467-470. δ18O is increasingly used to reconstruct Paleozoic–Triassic seawater temperature changes. Less attention has been paid to δ18O variation in time slices across paleoenvironments, within sample assemblages, or for reconstructing the thermal structure of Paleozoic oceans. Furthermore, there have been few independent tests of conodont ecologic models based on biofacies and lithofacies distributions. Here we present the first test of ecologic models for conodonts based on δ18O values of a Laurentian Lower Ordovician (Floian) shelf edge–upper slope assemblage in debrites of the proximal lower slope Shallow Bay Formation, Cow Head Group, western Newfoundland. Nine species yield a 1.6–1.8‰ intra-sample δ18O variability based on mixed tissue and white matter-only analyses, equivalent to an ～7–8 °C range. Linear mixed models demonstrate statistically significant differences between the δ18O of some species, supporting the interpretation that an isotopic and temperature gradient is preserved. By considering conodont δ18O in a geologic context, we propose an integrated paleoecologic and paleoceanographic model with species tiered pelagically through the water column, and confirm the utility of conodonts for water-mass characterization within Paleozoic oceans.White, A.J., Stevens, L.R., Lorenzi, V., Munoz, S.E., Lipo, C.P., Schroeder, S., 2018. An evaluation of fecal stanols as indicators of population change at Cahokia, Illinois. Journal of Archaeological Science 93, 129-134. stanols deposited in sediment provide evidence of trace human waste products and have been proposed as a proxy for measuring population change. Despite its potential to contribute to paleodemographic studies, the method has not been evaluated against conventional archaeological population reconstructions to determine its fidelity in identifying changes in ancient populations nor has it been applied in an environmental setting outside of the Arctic, where low temperatures enhance stanol preservation. We studied sediment cores recovered from a lake adjacent to Cahokia, the largest and most well-studied prehistoric mound center in North America. We found fecal stanol data closely track independently established population reconstructions from multiple sources, confirming the utility of the method and demonstrating its viability in temperate climates.Wicker, A.P., Carlton, D.D., Tanaka, K., Nishimura, M., Chen, V., Ogura, T., Hedgepeth, W., Schug, K.A., 2018. On-line supercritical fluid extraction—supercritical fluid chromatography-mass spectrometry of polycyclic aromatic hydrocarbons in soil. Journal of Chromatography B 1086, 82-88. supercritical fluid extraction – supercritical fluid chromatography – mass spectrometry (SFE-SFC-MS) has been applied for the determination of polycyclic aromatic hydrocarbons (PAHs) in soil. The purpose of this study was to develop and validate the first on-line SFE-SFC-MS method for the quantification of PAHs in various types of soil. By coupling the sample extraction on-line with chromatography and detection, sample preparation is minimized, diminishing sample loss and contamination, and significantly decreasing the required extraction time. Parameters for on-line extraction coupled to chromatographic analysis were optimized. The method was validated for concentrations of 10–1500?ng of PAHs per gram of soil in Certified Reference Material (CRM) sediment, clay, and sand with R2?≥?0.99. Limits of detection (LOD) were found in the range of 0.001–5?ng/g, and limits of quantification (LOQ) in the range of 5–15?ng/g. The method developed in this study can be effectively applied to the study of PAHs in the environment, and may lay the foundation for further applications of on-line SFE-SFC-MS.Wiggan, N.J., Riding, J.B., Fensome, R.A., Mattioli, E., 2018. The Bajocian (Middle Jurassic): A key interval in the early Mesozoic phytoplankton radiation. Earth-Science Reviews 180, 126-146. and coccolithophores are two of the most important groups of phytoplankton in the modern oceans. These groups originated in the Triassic and radiated through the early Mesozoic, rising to ecological prominence. Within this long-term radiation, important short-term intervals of evolutionary and ecological change can be recognised. The Bajocian (Middle Jurassic, ~170–168?Ma) was characterised by an important ecological transition within the coccolithophores, and the radiation of one of the principal families of cyst-forming dinoflagellates, the Gonyaulacaceae. During the Early Bajocian, the coccolith genus Watznaueria diversified and expanded ecologically to dominate coccolith floras, a situation which continued for the remainder of the Mesozoic. This pattern was paralleled within dinoflagellate cyst floras by the ecological dominance of the genus Dissiliodinium in the mid-palaeolatitudes. These phenomena appear to be linked to a positive carbon isotope shift, and an interval of enhanced productivity driven by a shift to a more humid climate, enhanced continental weathering and nutrient flux, or by changes in ocean circulation and The latest Early Bajocian to earliest Bathonian was then characterised by the rapid increase in diversity of dinoflagellate cysts within the family Gonyaulacaceae. Through this interval, the Gonyaulacaceae transitioned from being a relatively minor component of dinoflagellate cyst floras, to becoming one of the prominent groups of cyst-forming dinoflagellates, which has persisted to the Holocene. In Europe, the pattern of this radiation was strongly influenced by sea level, with the increase in gonyaulacacean diversity reflecting a major second-order transgression. On a finer scale, the main pulses of first appearances correlate with third-order transgressive episodes. A rise in sea level, coupled with changes in the tectonic configuration of ocean gateways, appears to have controlled the pattern of plankton diversification in Europe. These palaeoceanographic changes may have enhanced water-mass transfer between Europe, the northwest Tethys Ocean and the Hispanic Corridor, which promoted the floral interchange of dinoflagellates. Whilst sea-level rise and associated large-scale palaeoenvironmental shifts appear to have controlled the pattern of dinoflagellate cyst appearances in several regions outside Europe, there is no direct correlation between dinoflagellate cyst diversity and sea-level rise on a global scale. Although the Bajocian was transgressive in several regions, widespread flooded continental area was also present throughout the preceding Aalenian, an interval of low gonyaulacacean diversity. Moreover, although the Middle Jurassic was an interval of major climatic cooling, there was a ~5 myr gap between the onset of cooling and the radiation of gonyaulacaceans during the Bajocian. The Bajocian was, however, marked by a major evolutionary radiation in the pelagic realm, including ammonites, giant suspension feeding fishes and planktonic foraminifera. These phenomena may indicate an underlying ecological driver to the radiation of dinoflagellates during the Bajocian evolutionary explosion which could represent an extension of the Mesozoic Marine Revolution.William, J.C., Christopher, P.W., Peter, M.C., Chris, H., Jason, L., Stephen, S., Sarah, E.C., Edward, C.-P., Anna, B.H., Garry, H., Tom, P., 2018. Increased importance of methane reduction for a 1.5 degree target. Environmental Research Letters 13, Article 054003. understand the importance of methane on the levels of carbon emission reductions required to achieve temperature goals, a processed-based approach is necessary rather than reliance on the transient climate response to emissions. We show that plausible levels of methane (CH4) mitigation can make a substantial difference to the feasibility of achieving the Paris climate targets through increasing the allowable carbon emissions. This benefit is enhanced by the indirect effects of CH4 on ozone (O3). Here the differing effects of CH4 and CO2 on land carbon storage, including the effects of surface O3, lead to an additional increase in the allowable carbon emissions with CH4 mitigation. We find a simple robust relationship between the change in the 2100 CH4 concentration and the extra allowable cumulative carbon emissions between now and 2100 (0.27?±?0.05?GtC per ppb CH4). This relationship is independent of modelled climate sensitivity and precise temperature target, although later mitigation of CH4 reduces its value and thus methane reduction effectiveness. Up to 12% of this increase in allowable emissions is due to the effect of surface ozone. We conclude early mitigation of CH4 emissions would significantly increase the feasibility of stabilising global warming below 1.5?°C, alongside having co-benefits for human and ecosystem health.Witts, J.D., Newton, R.J., Mills, B.J.W., Wignall, P.B., Bottrell, S.H., Hall, J.L.O., Francis, J.E., Crame, A.J., 2018. The impact of the Cretaceous–Paleogene (K–Pg) mass extinction event on the global sulfur cycle: Evidence from Seymour Island, Antarctica. Geochimica et Cosmochimica Acta 230, 17-45. Cretaceous–Paleogene (K–Pg) mass extinction event 66 million years ago led to large changes to the global carbon cycle, primarily via a decrease in primary or export productivity of the oceans. However, the effects of this event and longer-term environmental changes during the Late Cretaceous on the global sulfur cycle are not well understood. We report new carbonate associated sulfate (CAS) sulfur isotope data derived from marine macrofossil shell material from a highly expanded high latitude Maastrichtian to Danian (69–65.5?Ma) succession located on Seymour Island, Antarctica. These data represent the highest resolution seawater sulfate record ever generated for this time interval, and are broadly in agreement with previous low-resolution estimates for the latest Cretaceous and Paleocene. A vigorous assessment of CAS preservation using sulfate oxygen, carbonate carbon and oxygen isotopes and trace element data, suggests factors affecting preservation of primary seawater CAS isotopes in ancient biogenic samples are complex, and not necessarily linked to the preservation of original carbonate mineralogy or chemistry. Primary data indicate a generally stable sulfur cycle in the early-mid Maastrichtian (69?Ma), with some fluctuations that could be related to increased pyrite burial during the ‘mid-Maastrichtian Event’. This is followed by an enigmatic +4‰ increase in δ34SCAS during the late Maastrichtian (68–66?Ma), culminating in a peak in values in the immediate aftermath of the K–Pg extinction which may be related to temporary development of oceanic anoxia in the aftermath of the Chicxulub bolide impact. There is no evidence of the direct influence of Deccan volcanism on the seawater sulfate isotopic record during the late Maastrichtian, nor of a direct influence by the Chicxulub impact itself. During the early Paleocene (magnetochron C29R) a prominent negative excursion in seawater δ34S of 3–4‰ suggests that a global decline in organic carbon burial related to collapse in export productivity, also impacted the sulfur cycle via a significant drop in pyrite burial. Box modelling suggests that to achieve an excursion of this magnitude, pyrite burial must be reduced by >15%, with a possible role for a short term increase in global weathering rates. Recovery of the sulfur cycle to pre-extinction values occurs at the same time (～320?kyrs) as initial carbon cycle recovery globally. These recoveries are also contemporaneous with an initial increase in local alpha diversity of marine macrofossil faunas, suggesting biosphere-geosphere links during recovery from the mass extinction. Modelling further indicates that concentrations of sulfate in the oceans must have been 2?mM, lower than previous estimates for the Late Cretaceous and Paleocene and an order of magnitude lower than today.Wolfe, J.M., Fournier, G.P., 2018. Horizontal gene transfer constrains the timing of methanogen evolution. Nature Ecology & Evolution 2, 897-903. methanogenesis may have been a major component of Earth’s carbon cycle during the Archaean eon, generating a methane greenhouse that increased global temperatures enough for a liquid hydrosphere, despite the Sun’s lower luminosity at the time. Evaluation of potential solutions to the ‘faint young Sun’ hypothesis by determining the age of microbial methanogenesis has been limited by ambiguous geochemical evidence and the absence of a diagnostic fossil record. To overcome these challenges, we use a temporal constraint: a horizontal gene transfer event from within archaeal methanogens to the ancestor of Cyanobacteria, one of the few microbial clades with recognized crown-group fossils. Results of molecular clock analyses calibrated by this horizontal-gene-transfer-propagated constraint show methanogens diverging within Euryarchaeota no later than 3.51 billion years ago, with methanogenesis itself probably evolving earlier. This timing provides independent support for scenarios wherein microbial methane production was important in maintaining temperatures on the early Earth.Wotherspoon, A.T.L., Reeves, K.L., Crawford, J., 2018. A comparison of structural-functional equation models to identify fatty acids on three common gas chromatography columns. Analytical Methods 10, 1747-1759. herein is a series of new structural-functional relationship equations which provide relevant structural information of unknown fatty acid methyl esters (double-bonds, chain-length, and omega-bond position) based upon temperature induced shifts in equivalent chain length's (ECLs). The induced ECL changes were accomplished upon two cyanoalkyl (Supelco SP-2560, fast GC; Varian Factor 4, VF-23) and one stabilised PEG column (Innowax). Regression on this data-set permitted the development of classical linear equations. To calculate the ECL values, bracketing saturated fatty acid methyl esters (FAMEs) were run in the same admixture as the unsaturated FAMEs. The equations developed for each of the three columns are demonstrated to have varying capacity to accurately identify the chain-length, double-bond number and omega-bond position.Wu, F., Zhao, Y., Fang, X., Meng, Q., 2018. An ecological response to the Eocene/Oligocene transition revealed by the δ13CTOC record, Lanzhou Basin, NE Tibetan Plateau. Journal of Asian Earth Sciences 159, 74-80. Eocene/Oligocene (E/O) transition, corresponds to an abrupt global cooling, thought to have been one of the greatest temperature changes in the mid-Cenozoic Earth’s history. Sparse studies have successfully reconstructed the terrestrial ecological response to this temperature change. Here, we report results from the study of organic carbon isotopes (δ13CTOC), together with n-alkanes biomarker analysis, in the Yongdeng Section, Lanzhou Basin, Northwest China, and discuss changes in δ13CTOC and their mechanisms. The results show that between 35.3?Ma and 31.0?Ma, δ13CTOC ranged from ?26.72‰ to ?21.27‰. The main change occurred at 33.4?Ma, when δ13CTOC became heavier by 3‰. At this time the long-chain n-alkane members (C27, C29 and C31) were dominant, suggesting the most likely sources of organic matter were terrestrial plants. Combining these results with existing measurements of plant δ13CTOC and sporopollen data in adjacent areas, we infer that this change at 33.4?Ma might have been caused by an increase in gymnosperm content especially coniferous trees adapted to cold climates, which have a heavier δ13CTOC than that of the angiosperms, this would have been a response to the global cooling characteristic of this period.Wu, H., He, W., Weldon, E.A., 2018. Prelude of benthic community collapse during the end-Permian mass extinction in siliciclastic offshore sub-basin: Brachiopod evidence from South China. Global and Planetary Change 163, 158-170. of the Permian–Triassic palaeocommunities from basinal facies in South China provides an insight into the environmental deterioration occurring in the prelude to the mass extinctio event. Quantitative and multivariate analyses on three brachiopod palaeocommunities from the Changhsingian to the earliest Triassic in basinal facies in South China have been undertaken in this study. Although the end-Permian extinction has been proved to be a one-stepped event, ecological warning signals appeared in the palaeocommunities long before the main pulse of the event. A brachiopod palaeocommunity turnover occurred in the upper part of the Clarkina changxingensis Zone, associated with a significant decrease of palaeocommunity diversity and brachiopod body size. During this turnover the dominant genera changed from Fusichonetes and Crurithyris (or/and Paracrurithyris) to the more competitive genus Crurithyris (or/and Paracrurithyris). The brachiopod palaeocommunity turnover was supposed to be triggered by the decreased marine primary productivity and increased volcanic activity. Moreover, such early warning signals are found not only in the deep-water siliceous facies, but also in the shallow-water clastic facies and carbonate rock facies in South China.Wu, H., Zhang, C., Ji, Y., Liu, R., Wu, H., Zhang, Y., Geng, Z., Zhang, Y., Yang, J., 2018. An improved method of characterizing the pore structure in tight oil reservoirs: Integrated NMR and constant-rate-controlled porosimetry data. Journal of Petroleum Science and Engineering 166, 778-796. oil reservoirs have an ultrafine pore structure with a large heterogeneity, which requires the integration of multiple techniques to characterize pore structure characteristics systematically and, therefore, to gain a better understanding of reservoir quality. Tight oil sandstone samples from the Upper Triassic Yanchang Formation in the Ordos basin were measured by nuclear magnetic resonance (NMR), constant-rate-controlled mercury porosimetry (CMP) and field emission scanning electron microscopy (FE-SEM) to investigate the pore structure characteristics and their control on petrophysical properties. Various types of pores from intergranular pores, dissolution pores, and intercrystalline pores to small microfractures occurred in the studied tight sandstones, which indicates that the NMR T2 distributions may be unimodal or bimodal in behaviour with a wide range. The short components of the T2 distributions match the CMP-derived throat size distributions regarding the dimensions, width and shape of the curves. We combined CMP and NMR to uncover the total pore size distribution; the size distributions of the throat and pore body range from 0.01 to 1?μm and from 0.1?μm to tens of microns respectively, which match the FE-SEM results. The pore body-to-throat ratio may be the important factor affecting the free water saturation in the pore body, which, in turn, is probably associated with the mineralogy of tight sandstones, in particular, the quartz, feldspar and clay mineral contents. The pore radius of 0.3–0.5?μm is the percolation threshold. The seepage porosity rather than total porosity overwhelmingly dominates the permeability, which, in turn, relates to the pore types, i.e., mesopores and macropores. An improved permeability prediction model is presented for tight oil reservoirs based on the contribution from different pore size intervals to the permeability. This model has a distinctly better performance than the classic models such as the Timur-Coates and SDR models and may be generalized to other similar reservoirs with ultrafine pore structures and significant volumes of clay minerals.Wu, L., Geng, A., Wang, P., 2018. Oil expulsion in marine shale and its influence on the evolution of nanopores during semi-closed pyrolysis. International Journal of Coal Geology 191, 125-134. expulsion is an important process for the evolution of shale, especially in the oil-generative window. Low oil expulsion efficiency will cause the retention of oil and gas in mature source rock. This study used semi-closed pyrolysis to simulate the hydrocarbon generation and expulsion process of the Xiamaling Formation marine shale at various conditions. Low-pressure nitrogen (N2) and carbon dioxide (CO2) gas adsorption isotherms were obtained for the original shale sample and its thermally evolved solid residues. The results showed that the amount of residual bitumen first increased with increasing expulsion efficiency (EE?&lt;?13.43%) and then remained constant with a further increase in EE. This finding implied that the saturation threshold for the source rock must be reached before oil expulsion can proceed. Meanwhile, the evolution of pore volumes with EE can be divided into two stages. The pore volumes decreased sharply in the first stage (EE?&lt;?13.43%), whereas they decreased slowly in the second stage (EE?&gt;?13.43%). The evolution of volume for micropores and fine mesopores with EE is very similar to that of expelled hydrocarbons. This similar evolution trend was further confirmed by the abovementioned oil expulsion model. This study enhanced understanding of the generation and evolution of shale gas in the oil-generative window.Xia, W., Dong, X., Zhang, Y., Ma, T., 2018. Biopolymer from marine Athelia and its application on heavy oil recovery in heterogeneous reservoir. Carbohydrate Polymers 195, 53-62. produced from marine Athelia strain presented unique Pseudoplastic behaviors under extremely-high temperature and salinity conditions. Characteristic analysis with FT-IR spectroscopy, high performance liquid chromatography, 1H and 13C NMR and two-dimensional COSY and HMQC spectra showed the structure of β-(1–6) glucans. Single-factor and orthogonal experiment design were used to optimize the yield, the maximum yield of the biopolymer was 28.32?g/L with 56.64% carbon conversion rate under optimized conditions. Economic investigation demonstrated that this novel biopolymer has great potential of commercialization with the competitive cost of $2896.04-5228.94 per ton for powder. Resistance factor and residual resistance factor were evaluated with core flooding experiments showed that this biopolymer had excellent performance of plugging capacity and profile modification, and indicating the great potential of application on heavy oil recovery.Xin, Y., Shi, Y., Niu, T., Wang, Q., Niu, W., Huang, X., Ding, W., Yang, L., Blankenship, R.E., Xu, X., Sun, F., 2018. Cryo-EM structure of the RC-LH core complex from an early branching photosynthetic prokaryote. Nature Communications 9, Article 1568. prokaryotes evolved diverse light-harvesting (LH) antennas to absorb sunlight and transfer energy to reaction centers (RC). The filamentous anoxygenic phototrophs (FAPs) are important early branching photosynthetic bacteria in understanding the origin and evolution of photosynthesis. How their photosynthetic machinery assembles for efficient energy transfer is yet to be elucidated. Here, we report the 4.1?? structure of photosynthetic core complex from Roseiflexus castenholzii by cryo-electron microscopy. The RC–LH complex has a tetra-heme cytochrome c bound RC encompassed by an elliptical LH ring that is assembled from 15 LHαβ subunits. An N-terminal transmembrane helix of cytochrome c inserts into the LH ring, not only yielding a tightly bound cytochrome c for rapid electron transfer, but also opening a slit in the LH ring, which is further flanked by a transmembrane helix from a newly discovered subunit X. These structural features suggest an unusual quinone exchange model of prokaryotic photosynthetic machinery.Xiong, X., Wang, J., Xiong, G., Wang, Z., Zhou, X., Deng, Q., Zhou, Y., Yang, X., 2018. Sedimentation and geochemistry of Upper Ordovician-Lower Silurian from northern Chongqing, and its environmental evolution: A study of Linxiang Formation to Longmaxi Formation of Yanmai profile from Chengkou Region. Acta Sedimentologica Sinica 36, 257-266. marl and grey-green mudstone of Linxiang Formation above nodular limestone develops upwards successively in Chengkou, Chongqing. Grey-green mudstone changes into dark silica mudstone of Wufeng Formation-Longmaxi Formation gradually. Changes from deep to shallow, then to deep of water depth are unraveled. Much anoxic and less oxic in redox condition upwards the Yanmai profile from Linxiang Formation to Wufeng Formation-Longmaxi Formation in general is indicated with the help of element geochemical analysis. A weak enhanced oxidation exists in the middle-upper portion of Linxiang Formation, implying structural uplift of Yichang movement. Higher paleoproductivity are seen in Guanyinqiao member and Layer 5 of Linxiang Formation, which are much oxic relatively, corresponding to the ascending current and the sea-level falling at that time, which are caused by the global gradual cooling down climate. The tectonic setting of Linxiang Formation-Longmaxi Formation inclines to an active continental arc environment. Less terrigenous constituent and more volcanic clastic component upwards Yanmai profile is indicated. The silica mudstone of Wufeng Formation and Longmaxi Formation shows apparent geochemical characteristics of hot water deposition, which may be influenced by deep hydrothermal activity.Xu, M., Binazadeh, M., Zolfaghari, A., Dehghanpour, H., 2018. Effects of dissolved oxygen on water imbibition in gas shales. Energy & Fuels 32, 4695-4704. the water uptake of gas shales is critical for designing and optimizing hydraulic fracturing operations during which a large volume of fracturing water containing dissolved oxygen is injected into tight reservoirs. Recent studies show that the dissolved oxygen may promote oxidation reactions which can affect salinity and pH value of flowback water; however, the effects of dissolved oxygen and oxidation reactions on water imbibition into the shale matrix and on the concentration of individual ions in flowback water are still poorly understood. In this study, we conduct water imbibition experiments under degassed and oxic conditions, and measure the imbibed water mass and concentrations of different ions in water. The results show that the initial rate and final amount of water imbibition are higher under degassed conditions compared with that under oxic conditions. These differences are mainly due to the enhanced dissolution of air in the shale pore network into the imbibing water under degassed conditions and the consequent increase in relative permeability of water. The results also suggest that oxidation of pyrite by dissolved oxygen produces sulfate and iron ions. The abundance of pores in the vicinity of pyrite minerals as observed in the SEM/EDS images provides a pyrite, water, and oxygen rich environment which favors pyrite oxidation.Yabuta, H.S., Scott A., Meech, K.J., 2018. Organic molecules and volatiles in comets. Elements 14, 101-106. molecules and volatiles (e.g. H2O, CO, CO2) are the major components of comets. The majority of the organic compounds found within comets were produced by ice irradiation in dense molecular clouds and in the protoplanetary disk prior to comet formation. Comets are essentially repositories of protocometary material. As a result, comets do not show the clear trends in chemical and isotopic compositions that would be expected from our understanding of their formation locations. Rather, comets record chemical evolution in the protoplanetary disk and allow us to unveil the formation history of the organics and volatiles.Yan, C., Jin, Z., Zhao, J., Du, W., Liu, Q., 2018. Influence of sedimentary environment on organic matter enrichment in shale: A case study of the Wufeng and Longmaxi Formations of the Sichuan Basin, China. Marine and Petroleum Geology 92, 880-894. two essential controls on the formation of organic matter (OM)-enriched shales, both paleoproductivity and preservation models remain controversial for the Wufeng and Longmaxi shales in the Sichuan Basin, southwest China. This study provides geochemical parameters as proxies for the paleoproductivity characteristics (Ba, P/Al, and (Ni+Cu)/Al), bottom water redox status (U/Th, V/(V+Ni), V/Cr, and Mo), and terrigenous clastic flux (Th and Al) of the Wufeng–Longmaxi Formations in the Sichuan Basin, a back-deep basin in a foreland basin system in southwest China. Combining these data with total organic carbon (TOC) content and sedimentation rate data obtained from graptolite zones allowed us to discuss the validity of these popular indices and to identify the main factors that controlled OM enrichment in the formations. TOC contents exceed 4?wt% in the upper Wufeng Formation to the bottom part of the Longmaxi Formation (LM1-3), which are the most OM-rich intervals. The average P/Al ratio for well JY2 in the Jiaoshiba area is 0.009, which is lower than those for well YY1 (0.028) in the Yongchuan area and well DY1 (0.02) in the Dingshan area, indicating the lowest productivity levels were in the Jiaoshiba area. Based on the redox proxies, the samples from well DY1 reflect less reducing bottom water conditions than those from wells JY2 and YY1. The Th and Al indices increase upwards, indicating that the terrigenous clastic input increased, and that those in the Yongchuan area were lower than those in the Jiaoshiba and Dingshan areas. The sedimentation rate was too low to dilute the OM in the Sichuan Basin, especially during the depositional time of the OM-rich intervals, such that the redox status of the water became more critical. Given the more strongly reducing conditions of the sedimentary environment and the high thermal maturity of the OM in this formation, the Ba concentrations appeared anomalously low and became inaccurate as a paleoproductivity index, as well as the validity of V, V/Cr, and V/(V+Ni) anomalously decreased as redox indices.Yan, D., Wong, Y.F., Whittock, S.P., Koutoulis, A., Shellie, R.A., Marriott, P.J., 2018. Sequential hybrid three-dimensional gas chromatography with accurate mass spectrometry: A novel tool for high-resolution characterization of multicomponent samples. Analytical Chemistry 90, 5264-5271. novel sequential three-dimensional gas chromatography–high-resolution time-of-flight mass spectrometry (3D GC–accTOFMS) approach for profiling secondary metabolites in complex plant extracts is described. This integrated system incorporates a nonpolar first-dimension (1Dnp) separation step, prior to a microfluidic heart-cut (H/C) of a targeted region(s) to a cryogenic trapping device, directly followed by the rapid reinjection of a trapped solute into a polar second-dimension (2DPEG) column for multidimensional separation (GCnp–GCPEG). For additional separation, the effluent from 2DPEG can then be modulated according to a comprehensive 2D GC process (GC×GC), using an ionic liquid phase as a third-dimension (3DIL) column, to produce a sequential GCnp–GCPEG×GCIL separation. Thus, the unresolved or poorly resolved components, or regions that require further separation, can be precisely selected and rapidly transferred for additional separation on 2D or 3D columns, based on the greater separation realized by these steps. The described integrated system can be used in a number of modes, but one useful approach is to target specific classes of compounds for improved resolution. This is demonstrated through the separation and detection of the oxygenated sesquiterpenes in hop (Humulus lupulus L.) essential oil and agarwood (Aquilaria malaccensis) oleoresin. Improved resolution and peak capacity were illustrated through the progressive comparison of the tentatively identified components for GCnp–GCPEG and GCnp–GCPEG×GCIL methods. Relative standard deviations of intraday retentions (1tR, 2tR,, and 3tR) and peak areas of ≤0.01, 0.07, 0.71, and 7.5% were achieved. This analytical approach comprising three GC column selectivities, hyphenated with high-resolution TOFMS detection, should be a valuable adjunct for the improved characterization of complex plant samples, particularly in the area of plant metabolomics.Yan, Z., Joshi, P., Gorski, C.A., Ferry, J.G., 2018. A biochemical framework for anaerobic oxidation of methane driven by Fe(III)-dependent respiration. Nature Communications 9, Article 1642. of methane by aerobic and anaerobic microbes governs the atmospheric level of this powerful greenhouse gas. Whereas a biochemical understanding of aerobic methanotrophy is well developed, a mechanistic understanding of anaerobic methanotrophy has been prevented by the unavailability of pure cultures. Here we report a biochemical investigation of Methanosarcina acetivorans, a methane-producing species capable of anaerobic methanotrophic growth dependent on reduction of Fe(III). Our findings support a pathway anchored by Fe(III)-dependent mechanisms for energy conservation driving endergonic reactions that are key to methanotrophic growth. The pathway is remarkably similar to pathways hypothesized for uncultured anaerobic methanotrophic archaea. The results contribute to an improved understanding of the methane cycle that is paramount to understanding human interventions influencing Earth’s climate. Finally, the pathway enables advanced development and optimization of biotechnologies converting methane to value-added products through metabolic engineering of M. acetivorans.Yang, X., Imasaka, T., Imasaka, T., 2018. Determination of pesticides by gas chromatography combined with mass spectrometry using femtosecond lasers emitting at 267, 400, and 800 nm as the ionization source. Analytical Chemistry 90, 4886-4893. standard sample mixture containing 51 pesticides was separated by gas chromatography (GC), and the constituents were identified by mass spectrometry (MS) using femtosecond lasers emitting at 267, 400, and 800 nm as the ionization source. A two-dimensional display of the GC/MS was successfully used for the determination of these compounds. A molecular ion was observed for 38 of the compounds at 267 nm and for 30 of the compounds at 800 nm, in contrast to 27 among 50 compounds when electron ionization was used. These results suggest that the ultraviolet laser is superior to the near-infrared laser for molecular weight determinations and for a more reliable analysis of these compounds. In order to study the conditions for optimal ionization, the experimental data were examined using the spectral properties (i.e., the excitation and ionization energies and absorption spectra for the neutral and ionized species) obtained by quantum chemical calculations. A few molecules remained unexplained by the currently reported rules, requiring additional rules for developing a full understanding of the femtosecond ionization process. The pesticides in the homogenized matrix obtained from kabosu (citrus sphaerocarpa) were measured using lasers emitting at 267 and 800 nm. The pesticides were clearly separated and measured on the two-dimensional display, especially for the data measured at 267 nm, suggesting that this technique would have potential for use in the practical trace analysis of the pesticides in the environment.Yang, X., Li, H., Yue, Y., Liu, S., Li, J., Xiong, P., 2017. The strata and palaeo-geomorphology framework at the end of Neoproterozoic and development mode of source rocks at the beginning of Cambrian in Tarim Basin, China. Journal of Natural Gas Geoscience 2, 313-322. to the new recognition from petroleum exploration of the Sinian to Cambrian in South China, it could be considered that the distribution of the early Cambrian source rocks was controlled by the palaeo-geomorphology at the end of Neoproterozoic in the Tarim Basin. Based on the zircon U-Pb dating of pyroclastic rock samples from the clastic rock stratum under the bottom of Cambrian carbonate rocks, the stratigraphic correlation of the Sinian to Cambrian was conducted to build the palaeo-geomorphology framework at the end of Neoproterozoic in Tarim Basin. Lastly, according to the development mode of source rocks at the beginning of Cambrian, the distribution of source rocks was predicted initially through the division of seismic facies. The youngest zircon concordia age of pyroclastic rocks from the bottom of well Tong 1 is 707±8Ma. It was revealed by the strata framework of the Sinian to Cambrian, the palaeo-geomorphology at the end of Neoproterozoic in Tarim Basin was characterized by an uplift highland in Bachu-Tazhong area, the south north high-low, and the west is higher than the east. The distribution of source rocks in the bottom of the Cambrian on the palaeo-platform and slopes was coincident with the Upper Sinian dolomite basically. But the contemporaneous sediment happened to be absent or changed in sedimentary facies on the uplift and its edges. From the seismic facies of the strata under the bottom of Cambrian, it could be concluded that source rocks in the type of the Xishanbraque Group (∈1xs) was limited in the Manjiaer Depression, while the source rocks in the type of the Yuertusi Group (∈1y) are widely distributed in south of Tabei Uplift, east Awat Depression, and even the Maigt Slope. However, among the west Awat Depression and western Tanguzibasi Depression, and the middle area of the Bachu-Tazhong Uplifts, the contemporaneous source rocks may have changed into sedimentary facies of tidal flat and lagoon, instead of deep shelf.Yang, X., Yan, D., Zhang, L., Zhang, B., Xu, H., Liu, W., Yun, J., 2018. The genesis of Hirnantian glaciation and paleo-ocean environment during Ordovician-Silurian transition. Acta Sedimentologica Sinica 36, 319-332. Ordovician-Silurian transition was an interval which revealed major changes in the Earth's biotic, climatic, and environmental systems, triggering the Hirnantian glaciation and end-Ordovician mass extinctions. The paleo-ocean environment experienced intense shift and exerted a crucial impact on the global cycles of carbon, molybdenum and sulfur during O-S transition. In addition, the weakness of continental weathering reduced 187Os and 87Sr flux, resulting in positive δ187Os and δ87Sr excursions. This first ice age, since the late Neoproterozoic, was the culmination of a cooling trend that had begun in the early or middle Ordovician, and was linked to some combination of reduced volcanic arc outgassing, enhanced silicate weathering, increased organic carbon burial and so on. There exist many problems about the genesis of Hirnantian glaciation, such as lacking in individual biostratigraphy which can control the carbonate platform in shallow water and mudstone in deep water simultaneously, as well as the high-precision analysis based on geochemical proxies and isochronous stratigraphic correlation. Meanwhile diagenesis, weathering and tectonic-thermal events also exerted an important impact on reconstruction of Hirnantian glaciation, resulting in inaccurate interpretation.Yang, Y., Bao, F., 2017. Characteristics of shale nanopore system and its internal gas flow: A case study of the lower Silurian Longmaxi Formation shale from Sichuan Basin, China. Journal of Natural Gas Geoscience 2, 303-311. gas flow in shale nanopores undergoes a transition from continuum-transition flow regimes to Knudsen diffusion, rather than the traditional Darcy flow, due to the dynamic properties of shale gas. Thus, becoming the premise in understanding gas flow regime within the shale nanopores to further investigate how shale permeability evolves during gas depletion as well as to predict gas production. The microstructure features of Longmaxi Formation shale (Longmaxi Shale), characterized by SEM imaging, MICP, and gas adsorption, are dominated by micropores and mesopores that are less than 10?nm in size on average. Judging from the pore sizes of Longmaxi Shale and the general reservoir pressures, the gas flow inside shale matrix is determined as slip flow and transition flow regimes by Knudsen number. About the investigation of the Barnett Shale, a second-order slip model is superior to the first-order slip model in describing apparent permeability of Longmaxi Shale. Then and there, the velocity profile and volumetric flow rate in Longmaxi Shale are discussed with a second-order slip model. The gas velocity on the pore walls becomes larger as pressure decreases. The gas production enhancement due to gas slippage effect brings about a higher yield than that of Darcy's Law. However, shale itself is highly heterogeneous in pore geometry. Therefore, the model construction of gas flow simulation must be based on refined shale pore models.Yang, Z., Cheng, B., Xu, Y., Liu, D., Ma, J., Ji, D., 2018. Stable isotopes in water indicate sources of nutrients that drive algal blooms in the tributary bay of a subtropical reservoir. Science of The Total Environment 634, 205-213. has become a severe environmental problem in some tributaries of the Three Gorges Reservoir (TGR) in China. A two-year field investigation of nutrients, oxygen stable isotopes (δ18O), and hydrogen stable isotopes (δD) was performed from January 2010 to December 2011 to determine the sources of nutrients in Xiangxi Bay (XXB). The results showed that nitrogen, phosphorus and silicon varied seasonally depending on hydrodynamic changes. The bottom-layer intrusive density current decreased nitrogen and silicon concentrations and increase phosphorus concentrations in XXB, while the middle-layer intrusive density current increased nitrogen and silicon concentrations and decrease phosphorus concentrations. The differences in δ18O and δD among the Yangtze River (YR), XXB and the region upstream of XXB were significant, and according to the tracer method, the estimated contribution ratios of nitrogen, phosphorus and silicon from the YR to XXB were much larger than those from the region upstream of XXB. These findings suggest that water quality in the TGR can be improved by reducing the pollution load throughout the upstream basin of the YR but not through decentralized efforts in only one or two tributary basins.Yao, H., Chen, X., Melinte-Dobrinescu, M.C., Wu, H., Liang, H., Weissert, H., 2018. Biostratigraphy, carbon isotopes and cyclostratigraphy of the Albian-Cenomanian transition and Oceanic Anoxic Event 1d in southern Tibet. Palaeogeography, Palaeoclimatology, Palaeoecology 499, 45-55. the Albian and Cenomanian, the Earth underwent profound climatic and oceanographic changes that were recorded in sedimentary successions on a global scale. Carbon isotope records spanning this time interval have been established in the western Tethys, eastern Pacific and North Atlantic Oceans, but not yet in the eastern Tethys Ocean. In this paper, we present biostratigraphic, chemostratigraphic and cyclostratigraphic characteristics of the uppermost Albian–lowermost Cenomanian in an eastern Tethyan section (Youxia, southern Tibet). Based on calcareous nannofossil biozones and the bulk rock δ13C curve, the Albian-Cenomanian boundary interval (ACBI) was identified and correlated to the western Tethys and Atlantic Oceans. In the Youxia section, δ13C values range from approximately 0‰ to +1.3‰ (?0.03‰ to +1.31‰). Four subevents (a, b, c and d) were distinguished in the ACBI carbon isotope curve via correlation with other sections. Based on a spectral analysis of the carbonate content, we recognized Milankovitch short eccentricity (~100?kyr) and precession (22.2?kyr) cycles, suggesting that orbital variations modulated depositional processes. The duration of the ACBI was estimated at ~311?kyr, while OAE 1d lasted for ~233?kyr in the eastern Tethys Ocean, consistent with the duration calculated from Atlantic Ocean records.Yi, B.Y., Lee, G.H., Kang, N.K., Yoo, D.G., Lee, J.Y., 2018. Deterministic estimation of gas-hydrate resource volume in a small area of the Ulleung Basin, East Sea (Japan Sea) from rock physics modeling and pre-stack inversion. Marine and Petroleum Geology 92, 597-608. made deterministic estimations of the gas-hydrate and in-place gas resource volumes in a small area in the northwestern Ulleung Basin, East Sea (Japan Sea) from 3-D pre-stack seismic data and well-log and core data from the UBGH2-6 well. We modeled the P-impedance (Ip) logs at the well for 0%–100% pore-space gas-hydrate saturation from the P-wave velocity (Vp) and density logs modeled by the simplified three-phase Biot-type equation (STPBE). Then, the Ip volume for the gas-hydrate-bearing zone (GHBZ) was constructed by pre-stack inversion and divided into 28 layers. The porosity and mineralogy along these layers were assumed to be uniform, respectively, to the porosity log upscaled to the layers and the sediment constituents at the well determined from the core samples. Next, the pore-space gas-hydrate saturation at every time sample of each layer was found by matching the Ip value of the time sample to the modeled Ip logs upscaled to the layers. The gas-hydrate saturation volume with a cell size of 25 m × 6.25 m × 1 ms was obtained from the product of the pore-space gas-hydrate saturation volume and the porosity volume. The gas-hydrate saturation volume was converted into the depth volume based on the Vp value at each cell found by matching the pore-space gas-hydrate saturation of the cell to the modeled Vp logs. The estimated total gas-hydrate and gas resource volumes are about 8.43 × 108 m3 and about 1.38 × 1011 m3, respectively.Yin, Z., Zhao, D., Pan, B., Zhao, F., Zeng, H., Li, G., Bottjer, D.J., Zhu, M., 2018. Early Cambrian animal diapause embryos revealed by X-ray tomography. Geology 46, 387-390. of animal embryos have profoundly improved our understanding of the early evolution of animal development. However, the fossil record of early animal embryos is extremely sparse. Here we present some three-dimensionally (3-D) phosphatized Archaeooides from the basal Cambrian in southern Shaanxi Province, China. The 3-D reconstructions of a number of specimens, aided by high-resolution X-ray tomography, demonstrate that these soft-bodied fossil organisms have a thick cyst characterized by pustule-like ornaments and vesicular structures. Furthermore, a multicellular inner body undergoing palintomic cell division is enclosed by the cyst. The suite of characters, including submillimeter to millimeter scale, a palintomic pattern of cell division, and a complex cyst wall microstructure, corroborate the hypothesis that Archaeooides fossils represent the embryonic remains of animals. More specifically, the structure of the cyst wall bears close comparison to the resting cysts of living invertebrates, allowing us to interpret Archaeooides as a diapause embryonic stage adapted to the temporally and spatially heterogeneous redox conditions that extended from the Ediacaran to the early Cambrian. The global distribution of Archaeooides indicates that these conditions were geographically widespread. Ultimately, Archaeooides provides evidence of the early evolution of this metazoan life history strategy as an adaptation to adverse environmental conditions. Its widespread occurrence in both conventional and exceptional taphonomic windows provides the potential for reconstructing its embryology and, by inference, the developmental evolution of early animals and their body plans.Youssif, M.I., El-Maghraby, R.M., Saleh, S.M., Elgibaly, A., 2018. Silica nanofluid flooding for enhanced oil recovery in sandstone rocks. Egyptian Journal of Petroleum 27, 105-110. oil recovery is proposed as a solution for declining oil production. One of the advanced trends in the petroleum industry is the application of nanotechnology for enhanced oil recovery. Silica nanoparticles (SiNPs) are believed to have the ability to improve oil production, while being environmentally friendly and of natural composition to sandstone oil reservoirs.In our work, we investigated the effect of silica nanoparticles flooding on the amount of oil recovered. Experiments were carried using commercial silica of approximately 20 nm in size. We used sandstone cores in the core flooding experiments. For one of the cores tertiary recovery is applied where brine imbibition was followed by nanofluid imbibition. While in the other cores secondary recovery was applied where primary drainage is directly followed by nanofluid imbibition. We investigated the effect of concentration of nanofluid on recovery; in addition, residual oil saturation was obtained to get the displacement efficiency. Silica nanofluid of concentration 0.01 wt%, 0.05 wt%, 0.1 wt% and 0.5 wt% were studied.The recovery factor improved with increasing the silica nanofluid concentration until optimum concentration was reached. The maximum oil recovery was achieved at optimum silica nanoparticles concentration of 0.1 wt%. The ultimate recovery of initial oil in place increased by 13.28% when using tertiary flooding of silica nanofluid compared to the recovery achieved by water flooding alone. Based on our experimental study, permeability impairment was investigated by studying the silica nanoparticles concentration, and the silica nanofluid injection rate. The permeability was measured before and after nanofluid injection. This helped us to understand the behavior of the silica nanoparticles in porous media. Results showed that silica nanofluid flooding is a potential tertiary enhanced oil recovery method after water flooding has ceased.Yuan, B., Moghanloo, R.G., 2018. Nanofluid pre-treatment, an effective strategy to improve the performance of low-salinity waterflooding. Journal of Petroleum Science and Engineering 165, 978-991. water (LSW) has been confirmed as a promising improved oil recovery technique. Implementing this technique, in some cases, induces fines migration and has posed great challenges on well injectivity. The aim of this work is to establish a mathematical foundation and explain the improved performance (both EOR and well injectivity) through nanofluid pre-treatment in single-layered and multi-layered heterogeneous reservoirs.We modify the fractional flow function while considering for fines straining effects in one-dimensional radial system, where fines migration varies with distance from the injection well owing to different drag forces. The interplay among nanoparticles, fines, and rocks is described through the maximum retention concentration of fine particles that depend upon both fluid quality and velocity. Our modification of the classical Buckley-Leverett theory leads to the characteristic curves along which water saturation varies. As low-salinity waterflooding continues, the induced fines migration delays the breakthrough of injected water, and bring uniform control of injected fluid entering each layer. On the other hand, fines migration may lead to the issue of well injectivity decline.Nanofluid pre-treatment can significantly mitigate fines migration near wellbore while it may occur far from the injection well. We discuss cases with different nanofluid treatment schemes prior to low-salinity waterflooding by comparing water-saturation profile, water-cut history plot, injection pressure, and oil recovery. A good agreement is obtained between semi-analytical solution and finite-difference simulation. It was observed that although nanofluid treatment slightly accelerate breakthrough of the injected water, it can help maintain long-term well injectivity and sweep efficiency. In practice, our work provides valuable insight to design of nanofluid utilization and improve efficiency of low-salinity waterflooding.Yuan, B., Wood, D.A., 2018. A comprehensive review of formation damage during enhanced oil recovery. Journal of Petroleum Science and Engineering 167, 287-299. of chemicals and thermal fluids in discovered petroleum reservoirs are becoming more commonplace to achieve improved recovery and sustainability of oil/gas resources. A lack of understanding on the induced damage in subsurface reservoirs is likely to bring downside risks associated with the projects of enhanced oil recovery and negative economic consequences. As a synthesis and extension of our recent work (Yuan and Wood, 2018), this paper aims to raise more awareness and promote more discussion on the mechanically, chemically, biologically and thermally induced damage issues associated with enhanced oil recovery processes, by integrating the state-of-the-art modelling, laboratory experiments and field applications. Potential formation damage issues are considered in the context of each specific enhanced oil and gas recovery project to answer why, where and when formation damage issues occur, their extents and impacts, and how to control, prevent and take advantages of such issues in various reservoir systems. Moreover, an integrated risk & opportunity assessment and management framework is proposed to improve outcomes of diverse enhanced oil recovery projects in practice. By providing an integrated understanding of formation damage from multi-disciplinary perspectives, it is possible to better understand and manage petroleum extraction using enhanced oil recovery techniques.Yudhowijoyo, A., Rafati, R., Sharifi Haddad, A., Raja, M.S., Hamidi, H., 2018. Subsurface methane leakage in unconventional shale gas reservoirs: A review of leakage pathways and current sealing techniques. Journal of Natural Gas Science and Engineering 54, 309-319. gas extraction is seen to be a bridge fuel to the future due to lower GHG emissions compared to oil. However, it is also one of the most controversial topics due to the involvement of fracking in their production. Based on the analysis performed in this review we found that despite hydraulic fracture propagation being a possible conduit of methane leakage, the major cause of gas leakage is through leaking wells within the vicinity of fracturing sites. Remedial attempts have revealed promising yet inconsistent results, with no concrete method established for the methane leakage mitigation from shale gas wells.Yurchenko, I.A., Moldowan, J.M., Peters, K.E., Magoon, L.B., Graham, S.A., 2018. Source rock heterogeneity and migrated hydrocarbons in the Triassic Shublik Formation and their implication for unconventional resource evaluation in Arctic Alaska. Marine and Petroleum Geology 92, 932-952. organic geochemical study of the Triassic Shublik Formation aims to investigate source rock heterogeneity, facies variation, and source and maturity of migrated hydrocarbons in the Tenneco Phoenix-1 well (OCS-Y-0338), drilled in offshore Arctic Alaska in 1986. Recovered continuous core is nearly 90?m thick continuous section throughout the entire Shublik Formation. Guided by previously published analyses of the Phoenix-1 core by Robison et al. (1996), this study provides the most detailed core-based analysis of the Shublik Formation to date. Analysis of biomarkers and diamondoids combined with Rock-Eval pyrolysis results indicates evidence of mature migrated hydrocarbons that may have affected previous interpretations of organic matter type and maturity of this core. Despite the variable lithology, four identified source rock intervals contain oil-prone type I kerogens with maturity ranging from immature to marginally mature. Biomarker analysis indicates the presence of two organic facies deposited under anoxic clay-poor and suboxic clay-rich environments that likely generated genetically distinct oils.?alait?, I., Maurer, A.F., Grimes, V., Silva, A.M., Ribeiro, S., Santos, J.F., Barrocas Dias, C., Valera, A.C., 2018. Diet and mobility of fauna from Late Neolithic–Chalcolithic site of Perdig?es, Portugal. Journal of Archaeological Science: Reports 19, 674-685. is located in the Alentejo region of south-eastern Portugal, with occupational phases dating from the Late Middle Neolithic to Late Chalcolithic/Early Bronze Age (middle 4th and 3rd?millennium?BCE) periods. It is a complex site that can be considered as a centre of social aggregation and a part of a larger settlement network. In this study, the nature of animal subsistence patterns as well as husbandry management practices and mobility are examined using stable carbon and nitrogen isotopic values from bone collagen of 35 archaeological faunal samples (Canis familiaris, Bos taurus, Bos primigenius, Sus sp., Ovis/Capra, Cervus elaphus, O. cuniculus, Equus sp.) and strontium isotope (87Sr/86Sr) analysis of 23 enamel samples. To provide necessary biological 87Sr/86Sr baseline data, the strontium isotopic composition of 14 modern plant samples were measured. The stable carbon and nitrogen isotope data shows that animals subsisted on a selection of C3 terrestrial resources, with subtle differences in animal husbandry practices in domesticated animals, while strontium isotope analysis shows that <5% of analysed fauna is consistent with the local bioavailable strontium isotopic range. Other animals can be divided into two clusters – those having strontium isotope values either lower or higher than the bioavailable range, showing that most of the fauna browsed and grazed within 10?km of the site's surrounding landscape, which is not such an unusual practice during prehistoric times.Zander, T., Choi, J.C., Vanneste, M., Berndt, C., Dannowski, A., Carlton, B., Bialas, J., 2018. Potential impacts of gas hydrate exploitation on slope stability in the Danube deep-sea fan, Black Sea. Marine and Petroleum Geology 92, 1056-1068. production from gas hydrate reservoirs is only economically viable for hydrate reservoirs in permeable sediments. The most suitable known prospect in European waters is the paleo Danube deep-sea fan in the Bulgarian exclusive economic zone in the Black Sea where a gas hydrate reservoir is found 60?m below the seafloor in water depths of about 1500?m. To investigate the hazards associated with gas production-induced slope failures we carried out a slope stability analysis for this area. Screening of the area based on multibeam bathymetry data shows that the area is overall stable with some critical slopes at the inner levees of the paleo channels. Hydrate production using the depressurization method will increase the effective stresses in the reservoir beyond pre-consolidation stress, which results in sediment compaction and seafloor subsidence. The modeling results show that subsidence would locally be in the order of up to 0.4?m, but it remains confined to the immediate vicinity above the production site. Our simulations show that the Factor of Safety against slope failure (1.27) is not affected by the production process, and it is more likely that a landslide is triggered by an earthquake than by production itself. If a landslide were to happen, the mobilized sediments on the most likely failure plane could generate a landslide that would hit the production site with velocities of up to 10?m?s?1. This case study shows that even in the case of production from very shallow gas hydrate reservoirs the threat of naturally occurring slope failures may be greater than that of hydrate production itself and has to be considered carefully in hazard assessments.Zavarzina, D.G., Gavrilov, S.N., Zhilina, T.N., 2018. Direct Fe(III) reduction from synthetic ferrihydrite by haloalkaliphilic lithotrophic sulfidogens. Microbiology 87, 164-172. to reduce insoluble Fe(III) compounds has not been shown for alkaliphilic lithotrophic sulfate and sulfur reducers. Detection of this metabolic process in sulfidogenic prokaryotes could significantly expand the present knowledge on physicochemical range of their growth and physiological activity, which is now limited by low negative ambient redox potential. Capacity for direct reduction of Fe(III) from chemically synthesized ferrihydrite was tested for eight species of hydrogenotrophic haloalkaliphilic sulfidogens grown with formate or H2 as electron donors in the absence of sulfur compounds in the medium. Out of eight tested species, six reduced iron with formate and five, with hydrogen as the electron donor. Iron reduction correlated with stimulation of growth on formate or hydrogen only in two sulfidogenic species. Analysis of available genomes of five tested species revealed that only Dethiobacter alkaliphilus and Desulfuribacillus alkaliarsenatis possess the gene sets of multiheme cytochromes c required for typical dissimilatory iron reduction. The presence of these genes in two strains with high iron-reducing activity indicates the capacity of some haloalkaliphilic sulfidogenic bacteria for carrying out direct dissimilatory reduction of insoluble Fe(III) forms in the absence of sulfur-containing electron acceptors, i.e., without using sulfide as a soluble mediator of iron reduction. In other studied microorganisms, the ability to reduce iron is probably caused by nonspecific metabolic activity and is not directly linked to energy generation for growth, although the rates of Fe(III) reduction determined in our experiments make it possible to suggest significant role of sulfidogenic microorganisms (normally reducing sulfur and sulfate) in the iron cycle in haloalkaline ecosystems upon decreased content of sulfur compounds. Original Russian Text ? D.G. Zavarzina, S.N. Gavrilov, T.N. Zhilina, 2018, published in Mikrobiologiya, 2018, Vol. 87, No. 2, pp. 114–124.Zeng, Z., Liu, Y., Zhong, H., Xiao, R., Zeng, G., Liu, Z., Cheng, M., Lai, C., Zhang, C., Liu, G., Qin, L., 2018. Mechanisms for rhamnolipids-mediated biodegradation of hydrophobic organic compounds. Science of The Total Environment 634, 1-11. widespread existence of hydrophobic organic compounds (HOCs) in soil and water poses a potential health hazard to human, such as skin diseases, heart diseases, carcinogenesis, etc. Surfactant-enhanced bioremediation has been regarded as one of the most viable technologies to treat HOCs contaminated soil and groundwater. As a biosurfactant that has been intensively studied, rhamnolipids have shown to enhance biodegradation of HOCs in the environment, however, the underlying mechanisms are not fully disclosed. In this paper, properties and production of rhamnolipids are summarized. Then effects of rhamnolipids on the biodegradation of HOCs, including solubilization, altering cell affinity to HOCs, and facilitating microbial uptake are reviewed in detail. Special attention is paid to how rhamnolipids change the bioavailability of HOCs, which are crucial for understanding the mechanism of rhamnolipids-mediated biodegradation. The biodegradation and toxicity of rhamnolipids are also discussed. Finally, perspectives and future research directions are proposed. This review adds insight to rhamnolipids-enhanced biodegradation process, and helps in application of rhamnolipids in bioremediation.Zhang, C., Lin, J., Li, S., Dong, H., Wang, F., Xie, S., 2018. Tectonomicrobiology: A new paradigm for geobiological research. Science China Earth Sciences 61, 494-498. is a sub-discipline of geobiology and emphasizes the interaction between microorganisms and their environment on Earth. There is a need to explicitly emphasize the biogeochemical processes performed by microorganisms associated with Earth’s tectonic activities, especially under the framework of the modern theory of plate tectonics. Tectonomicrobiology aims to create a better synergy between microbial and active tectonic processes. This explicit synergy should also foster better communications between solid Earth scientists and life scientists in terms of holistic Earth system dynamics at both tectonic and micro-scales.Zhang, J., Anderson, K., Britt, D., Liang, Y., 2018. Sustaining biogenic methane release from Illinois coal in a fermentor for one year. Fuel 227, 27-34. evaluate coal biogasification in a larger reactor over a longer duration as compared to studies reported so far, a 3-liter fermentor was established. During the one-year study, a nutrient recipe was added three times to sustain methane release from Illinois bituminous coal. The cumulated methane production was 5171?ft3/ton with a methane content of 75.4% on day 365. After the fermentation was terminated, the residual coal and fermentation broth were characterized in detail. Compared to the untreated coal, the treated coal residue appeared to be finer and highly degraded with less carbon but more ash. Based on mass balance, volatile and fixed carbon decreased 15.9% and 29.6%, respectively, using the untreated coal as the baseline. According to GC/MS analysis, the fermentation broth contained mainly three groups of compounds: fatty acids and their derivatives, aromatics, and hydrocarbons. In addition, the fermentation broth was found to have effect on flocculation and contained compounds that possessed surface-active properties. Further investigations are needed to identify these chemicals responsible for these activities and develop ways to further enhance coal biogasification based upon results obtained then.Zhang, S., Tang, S., Zhang, J., Pan, Z., 2018. Pore structure characteristics of China sapropelic coal and their development influence factors. Journal of Natural Gas Science and Engineering 53, 370-384. coal is similar to humic coal in organic matter content, and to shale in kerogen type. Research on the sapropelic coal pore structure can help to understand the differences between humic coal and shale in pore development. In this paper, the pore structures of 21 sapropelic coal samples from Shaanxi, Shanxi, Gansu and Shandong provinces were determined, coupled with proximate analysis, reflectance (Ro), maceral and fractal analysis, scanning electron microscopy (SEM), mercury porosimetry (MIP), and low-temperature nitrogen adsorption tests. The results indicate that Late Paleozoic and later age sapropelic coals are low rank with Ro values ranging from 0.31% to 0.82%, and Early Paleozoic sapropelic coals are high rank with Ro values ranging from 2.64% to 5.89%. The low-rank coals are mainly of Types IIa and IIb kerogen containing humic detritus. The high-rank coals are of Type I kerogen composed by bitumen matrix and minerals. According to the normalized pore size distribution (PSD) curves of MIP and low-temperature N2 adsorption, three pore types (Type IM, Type IIM, and Type IIIM) for seepage pores and three pore types (Type IN, Type IIN, and Type IIIN) for adsorption pores are divided, respectively. For seepage pores, all the low-rank sapropelic coals have the Type IM PSD, while the high-rank coals contain Type IM, Type IIM and Type IIIM PSDs. From Type IM via Type IIM, to Type IIIM, the content of mesopores and macropores increases; meanwhile, the fractal dimensions (Dt, derived from the thermodynamics model) also increase. For adsorption pores, from type IN via type IIN to type IIIN, the BET specific surface area (SSA), density function theory (DFT) volume and Frenkele-Halseye-Hill (FHH) fractal dimension (Df) successively increase, and the medium pore diameters successively decrease. It was found that the development of the saproplelic coal pore structure was controlled by the integrated effects of coal rank and composition. Generally, the seepage pores of sapropelic coals studied in this work are mainly primary or intergranular pores with weak correlation with the coal composition. However, the development of the adsorption pores has obvious correlations with organic matter content, ash yield rate (Aad) and moisture content (Mad).Zhang, T., He, Y., Yang, Y., Wu, K., 2017. Molecular simulation of shale gas adsorption in organic-matter nanopore. Journal of Natural Gas Geoscience 2, 323-332. gas is a kind of unconventional oil-gas resource with tremendous potential. For thorough understanding of the methaneadsorption and micromechanism in organic-matter nanopores of the shale and better acquaintances of the occurrence form, graphite slit-pores were set up as a representation of organic-matter nanopores by using Material Studio, and the grand canonical Monte Carlo method, molecular mechanics and molecular dynamics were used for the simulation of adsorption and diffusion behaviors in organic-matter pores on CH4 and CO2 at the shale gas common burial depth of 2–4 km in the Upper Yangtze Plate. The results indicated that the adsorptions of CH4 and CO2 were physical and the optimal storage depth was 2 km; The mixed adsorption data showed the rationality of exploit shale gas by injecting CO2 to exchange CH4, and the optimal burial depth was 4 km; The relative density of CH4 and CO2 along the normal direction of the pore inwall showed a trend of symmetric distribution and apparent adsorption stratifications appeared. As a whole, the self-diffusion coefficient of CH4 and CO2 increased with the increase of burial depth, and it's consistent with the reasons for such changes of adsorption amount and adsorption heat.Zhao, L., Zhao, Y., Wang, X., Yang, J., Luo, S., Tian, Y., Zhen, X., 2018. Dynamic changes of dissolved organic matter during nitrate transport in a loose-pore geothermal reservoir. Chemical Geology 487, 76-85. dynamic changes of dissolved organic matter (DOM) during nitrate transport were investigated to explore the relationship between carbon sources and the nitrate reduction process in a loose-pore geothermal reservoir. Batch experiments were performed at four temperature levels (4?°C, 25?°C, 35?°C, and 45?°C) to determine the characteristics of the DOM extracted from the geothermal reservoir matrix. According to its fluorescence spectra, fluorescence index (FI), and biological/autochthonous index (BIX), the DOM was mainly derived by autochthonous microbial processes. Column experiments were carried out at 25?°C, 35?°C and 45?°C to determine the dynamic changes of the matrix DOM during nitrate transport in the simulated geothermal reservoir. The dynamic changes of the FIs; the fluorescence intensities (divided by dissolved organic carbon) of peaks B1 and T1; and concentrations of NO3?-N, NO2?-N, NH4+-N and the total dissolved inorganic nitrogen (∑N) in the column effluent within 412?h (10.5?PV) indicated that the reduction rate of nitrate and the production of denitrifiers were enhanced with an increase in temperature. Although a red shift of peak T2 during experiment at 35 and 45?°C implied the variation of the aromatic components of DOM during denitrification, low molecular weight aliphatic hydrocarbons in the matrix DOM were more active as electron donors than the aromatic compounds, as indicated by the variations of the effluent pH and SUVA254 values. No obvious trend in the variation of the BIX with temperature was observed possibly due to the short test duration of the column experiments. The findings should advance our understanding of the biological transformation of nitrate in loose-pore geothermal reservoirs.Zhao, X., Deng, J., Rao, Z., Wen, Z., Bi, C., Yi, L., Lu, C., Liu, C., 2018. Shallow gas characteristics in Mohe Basin, Northeast China and its significance to gas hydrate formation. Acta Petrolei Sinica 39, 266-277. gas source is one of key factors for gas hydrate formation, and for long time is a puzzle during the gas hydrate exploration in the permafrost of Northeast China. In this study, hundreds of gas samples from the drilled cores of four wells in Mohe Basin were analyzed in detail, and it is obtained that the hydrocarbon gas content in the shallow part of Mohe Basin (above 1 200 m under subsurface)is in the range of 10-100 mL/L, and several individual contents exceed 100 mL/L. In general, the muddy rocks, fracture zones and deeper formations (>2 300 m)have high gas contents, while the carbon-bearing or carbonaceous mudstones have higher gas contents. The hydrocarbon gas in the shallow part of Mohe Permafrost is dominated by biogas; at the depth of 1 200-2 300 m, mixed gas could exist; conventional natural gas formed by pyrolysis shall occur in the deep formations. The shallow biogas is the main gas source for gas hydrate formation in the Mohe Permafrost, Northeast China, which has a great significance to guide the exploration of gas hydrate in the Northeast China and even the whole China land.Zhao, Y.-l., Wang, Z.-m., Ye, J.-p., Sun, H.-s., Gu, J.-y., 2018. Lattice Boltzmann simulation of gas flow and permeability prediction in coal fracture networks. Journal of Natural Gas Science and Engineering 53, 153-162. cleat or natural fracture system is a dominant factor controlling the permeability of coal seams. Gas permeability and porosity of coal samples with artificially generated fractures are measured under varying effective stress. Based on the experimental results and the Walsh model, fracture width and roughness are estimated. Considering the fracture aperture and roughness, we present a 3D geometry model to reconstruct coal fracture networks on the basis of the Voronoi tessellations. The lattice Boltzmann method (LBM) is applied to simulate fracture flows and to predict the associated permeability. For comparison purposes, simulations in a single fracture are carried out initially. For a single smooth fracture, the results of LBM simulations show a good agreement with the cubic law. For a single rough fracture, the cubic law overestimates the permeability, and it is two to four orders of magnitude higher than the laboratory measurement. The predicted permeability by LBM simulation is in acceptable agreement with laboratory measurement. Furthermore, the flows through the fracture networks with smooth fracture surfaces are simulated. By comparison to the matchstick model, simulation errors are mostly within 30%. Finally, the effects of structure, surface roughness and aperture on flows in fracture networks with rough fracture surfaces are investigated. The present study provides a promising approach to predict the associated permeability and transport characteristics in coal fracture networks.Zhou, Y., Wu, S., Li, Z., Zhu, R., Xie, S., Jing, C., Lei, L., 2018. Multifractal study of three-dimensional pore structure of sand-conglomerate reservoir based on CT images. Energy & Fuels 32, 4797-4807. reservoir has been scarcely studied, and there is no effective method available for quantitative characterization of pore structure of such a reservoir. In this paper, a multifractal study was made on the Triassic Karamay Formation sand-conglomerate reservoir in the Mahu rim region, the Junggar Basin, by using a variety of high-resolution analysis methods, such as Micro-CT, QEMSCAN, and MAPS, in order to quantitatively characterize the heterogeneity of pore size distribution, relative differentiation of large and small pores, and mineral composition. The results reveal that the multifractal parameters have more influence on permeability than on porosity. The smaller the Δα (the multifractal spectral width) and the larger the Δf (the difference in fractal dimension of the maximum and minimum probability subsets), the better the reservoir physical property. To some extent, the relationship between multifractal parameters and mineral composition provides an opportunity to reflect the diagenesis. There is a positive correlation between the clay mineral content and the heterogeneity of the microscopic pore structure of the reservoir. Kaolinite and chlorite cementations are the most significant factors that damage the reservoir pore space. This understanding matches well with the MAPS and QEMSCAN results. With outstanding advantage in quantitatively evaluating the heterogeneity of pore structure of sand-conglomerate reservoir, multifractal theory provides a new idea and method for quantitative characterization of pore structure of other types of heterogeneous oil reservoirs.Zhu, B., Jiang, S., Pi, D., Ge, L., Yang, J., 2018. Trace elements characteristics of black shales from the Ediacaran Doushantuo Formation, Hubei Province, South China: Implications for redox and open vs. restricted basin conditions. Journal of Earth Science 29, 342-352. the present study, we carried out trace element analyses of black shales of the Ediacaran Doushantou Formation from two sections (Jiulongwan, Baiguoyuan) in Hubei Province, South China. Mo-U characteristics of black shales from the two sections and compiled Mo-U data of Doushantuo black shales from sections of a variety of sedimentary facies described the temporal/spatial variability in the redox conditions of paleo-seawater during deposition of the Doushantuo Formation. Changes in Mo-U patterns of the Doushantuo Member II (DST2) shales of open marine environments are consistent with a shift from a predominately oxic to a predominately anoxic ocean during their deposition. Mo-U patterns of the DST2 black shales from intra-shelf sections reflect basin restriction may have happened in the intra-shelf basin and are compatible with the redox-stratified model of the intra-shelf basin. Mo-U patterns of black shales of the Doushantuo Member IV (DST4) reveal that the shales from intra-shelf sections have more pronounced Mo enrichment and more significant enrichment of Mo over U than the slope shales, indicating the operation of a Mn particulate shuttle in the intra-shelf basin. High Mo/TOC ratios of the DST4 at the intra-shelf sections, in combination with similar Mo-TOC patterns of the DST4 from both intra-shelf and slope sections, indicate the intrashelf basin was well connected to the open ocean during deposition of the DST4.Zhu, D., Liu, Q., Meng, Q., Jin, Z., 2018. Enhanced effects of large-scale CO2 transportation on oil accumulation in oil-gas-bearing basins — Implications from supercritical CO2 extraction of source rocks and a typical case study. Marine and Petroleum Geology 92, 493-504. mantle-derived CO2 emplacement and co-accumulation of CO2 and crude oil have been discovered in oil-gas bearing basins in eastern China and many other areas worldwide. To investigate the effect of the natural supercritical CO2 on the migration of crude oil as well as on the formation of oil reservoirs, experiments on supercritical CO2 extraction (SCE) and traditional chloroform extraction (CE) of hydrocarbon source rocks were carried out and the geochemical characteristics of the Huangqiao CO2-oil reservoir in the Subei Basin, eastern China were investigated. The SCE yielded a large proportion of the hydrocarbons in the Permian mudstone source rocks at 110 °C under 30 MPa. Compared with the traditional chloroform extraction (CE), the SCE-retrieved organic compounds are dominated by saturated hydrocarbons and contain a relatively higher concentration of small molecular mass compounds. Many wells in the Huangqiao reservoir yielded large amounts of CO2 from several formations, such as the Triassic Qinglong Formation (T1q) and the Permian Longtang Formation (P2l). Accompanying the CO2 flow, a certain amount of oil is commonly recovered. The oil is mainly light oil or condensate oil with a relative density of 0.7933–0.8308, and it contains 90.06–97.37% saturated hydrocarbons. Compared with hydrocarbons in the Permian source rocks, the oil accompanying the CO2 in the Huangqiao reservoir contains more C20- hydrocarbons and less C21+ hydrocarbons. The oil accompanying the CO2 has a similar composition to the SCE extracts from the source rocks, namely, both contain a relatively high concentration of low molecular mass hydrocarbons. Therefore, it can be concluded that, in the Huangqiao area, during movement upward along deep faults and fractures or flow through source rocks, the deep supercritical CO2 naturally extracted hydrocarbons, especially small molecular hydrocarbons, from the source rocks, and then brought them to the shallow strata to form the CO2-oil coupling reservoirs.Zhu, G., Wang, M., Zhang, Y., Zhang, Z., 2018. Higher ethanodiamondoids in petroleum. Energy & Fuels 32, 4996-5000. ethanodiamondoids (ethanodiamantanes and ethanotriamantanes) have been identified for the first time in petroleum. Because ethanodiamondoids are the most thermally stable complex saturated hydrocarbons in petroleum, they appear to reflect the level of oil thermal stress and may serve as a promising reliable indicator for oil cracking and oil maturity. As the ethano-bridged diamond lattice molecules, the extraordinarily thermostable characteristics and predictable derivatizable features of ethanodiamondoids make them attractive components for nanomaterials and devices as well as heat-resistant materials.Zhu, X., Jia, G., Mao, S., Yan, W., 2018. Sediment records of long chain alkyl diols in an upwelling area of the coastal northern South China Sea. Organic Geochemistry 121, 1-9. chain alkyl diols in sediment cores were studied in the Yuedong Upwelling (YDU) area in the coastal northern South China Sea to investigate whether sea surface temperature (SST) and upwelling intensity over the last few decades can be traced by the diol-derived indices, i.e., the LDI (long chain diol index) as a proxy for SST and the DI-1 and DI-2 (diol index 1 and 2) as proxies for upwelling intensity. The influence of riverine long chain alkyl diols (e.g., 1,13- and 1,15-diols), which may affect LDI-reconstructed SSTs, was largely ruled out based on the comparison between diol distributions in suspended particulate materials in the Pearl River estuary and the core sediments. LDI-derived SSTs in downcore sediments matched well with local annual mean SSTs. The records of DI-2 changed in parallel with the local wind stress and inversely with SST at times of upwelling, suggesting that DI-2 is an effective proxy for upwelling intensity of YDU. The DI-1 showed a generally inverse variation pattern with DI-2, implying a major influence by SST, and it is thus not an applicable upwelling indicator for YDU. A negative relationship of DI-1 and a positive relationship of DI-2 with LDI-derived SST were observed. This occurrence might be attributed to El Ni?o–Southern Oscillation (ENSO), because the SST and upwelling intensity were largely modulated by ENSO, showing a warm annual mean SST during the years of enhanced El Ni?o and intensified summer upwelling.Ziegs, V., Noah, M., Poetz, S., Horsfield, B., Hartwig, A., Rinna, J., Skeie, J.E., 2018. Unravelling maturity- and migration-related carbazole and phenol distributions in Central Graben crude oils. Marine and Petroleum Geology 94, 114-130. this contribution we present the results of an integrated investigation of selected nitrogen- and oxygen-bearing compounds in Norwegian Central Graben crude oils. We first provide an interpretation framework built on hydrocarbon biomarkers, and then use this framework to relate polar compound geochemistry to the influences of source facies (Farsund versus Mandal Formations), maturity, migration and reservoir lithology. Oil maturity could be assessed using established changes in carbazole annelation (N1 DBE 9 vs. 12 vs. 15 classes), as well as hydrocarbon biomarkers. 29Ts/(29Ts?+?NH) correlated best with the polar compound maturity data. Secondary migration fractionation appears nevertheless to have played a role, as seen by increased DBE 9 and 12 carbazole and benzocarbazole proportions and a loss of C2-3 DBE 12 homologues within carbonate reservoirs as compared to intraformational Upper Jurassic siliciclastic reservoirs. Thus migration distances, pathways and wettability of carrier systems ostensibly play a significant role in carbazole distributions of the Central Graben oils, manifesting itself as apparent maturity retardation. In an attempt to eliminate the migration component from maturity assessment, we here present a novel ternary diagram including dibenzocarbazoles (N1 DBE 15) and phenolic species (O1 DBE 4 and 5) based on a single measurement using the FT-ICR-MS. However, the integration of such results into 3D-modelling software must be conducted to clarify source kitchen, migration pathways and distances.Zolensky, M.E., Grady, M.M., 2018. Comets: Where we are, how we got here, and where we want to go next. Elements 14, 83-86. introduce the principal mysteries surrounding comets; discuss the proposed importance of comets to the origin of water and organic compounds in the inner solar system; and summarize the history of cometary observation, study, and exploration over the past 22 centuries.Zou, C., Zhao, Q., Dong, D., Yang, Z., Qiu, Z., Liang, F., Wang, N., Huang, Y., Duan, A., Zhang, Q., Hu, Z., 2017. Geological characteristics, main challenges and future prospect of shale gas. Journal of Natural Gas Geoscience 2, 273-288. development of shale gas in the United States has made a breakthrough, profoundly changed the pattern of oil and gas supply. It created the “shale gas revolution” on a global scale. Based on the practice of shale gas development in China and abroad, this paper aims to: (1) Summarize 5 basic characteristics, which are shale gas resource distribution, reservoir space, sweet spot area (section), hydrocarbon type and development mode. (2) Divide China shale development into three stages: scientific exploration, technological breakthrough and mature development. The United States is divided into three stages: scientific exploration, technological breakthrough and mature development. The United States is divided into three stages: scientific exploration, technological breakthrough and mature development. (3) Identify 4 challenges in the future development of China shale gas industry. It includes non-marine shale gas potential, core technology and equipment for resource deep than 3500?m, complex surface “factory mode” production, human geography and other non-technical factors. (4) Process economic evaluation under the conditions of government financial subsidies. China's shale gas project FIRR is about 8.0%–9.0%. Considering the global shale gas resources, consumer demand and other factors, it global shale gas production is expected to reach 1.1?×?1012m3 by 2040.Zuo, J.Y., Guo, X., Liu, Y., Pan, S., Canas, J., Mullins, O.C., 2018. Impact of capillary pressure and nanopore confinement on phase behaviors of shale gas and oil. Energy & Fuels 32, 4705-4714. this paper, a general framework of theoretical models and algorithm is developed to predict phase envelopes (saturation points) and quality lines of shale gas and oil in nanopores. The equation of state (EOS) and the modified Young–Laplace equation are used to take into consideration the effect of phase behavior and capillary pressure on phase envelopes, respectively. The Zuo and Stenby parachor model is applied to determine interfacial tensions between the vapor and liquid phases. In addition, a critical property shift of pure components is utilized to account for the impact of nanopore confinement on phase envelopes. The algorithm has proven to be robust for generating phase envelopes including critical points, cricondentherms (maximum temperatures), and cricondenbars (maximum pressures) for a variety of fluids at different compositions, vapor mole fractions (quality lines), and pore sizes. The models and algorithm are then used to explain the recently measured data of normal boiling point or bubble point temperatures for pure n-heptane in type I kerogen, binary mixtures of n-pentane + n-hexane and n-pentane + n-heptane, and a ternary mixture of n-pentane + n-hexane + n-heptane in the nanofluidic devices. For pure n-heptane in type I kerogen, with a presumption of nanopores being completely wetted by the liquid phase, the models agree well with the experimental data within a reasonable range of type I kerogen nanopore distributions in the presence of capillary pressure effect only as well as both capillary pressure and nanopore confinement effects. However, for the binary and ternary mixtures in the nanofluidic devices, the complete wettability assumption seems no longer valid. The wetting fluid–wall interaction parameter (λ) is then adjusted to match the experimental data at the nanopore radius of 5 nm. The adjusted parameters are λ = ?142.2 ～ ?167.5 and λ = ?14.0 for the three tested binary and ternary mixtures in the presence of capillary pressure effect only as well as both capillary pressure and nanopore confinement effects, respectively. The models provide not only good predictions at other radii but also a correct trend for the mixtures in the presence of capillary pressure effect only but a wrong trend against the experimental data in the presence of both capillary pressure and nanopore confinement effects. In addition, in the presence of both capillary pressure and confinement effects, a decrease in bubble and dew point pressures with decreasing pore radius is observed for shale gas and oil. For gas condensate mixtures, field production data show that produced liquid and gas ratios decrease even at reservoir pressures above bulk retrograde dew points. It is obvious that the model with critical property shift contradicts the field observation. More research activities in this area are required. Although in the presence of capillary pressure effect only, a decrease in bubble point pressures is estimated for shale oil, an increase in dew point pressures is predicted for shale gas with decreasing pore radius.Zwicker, J., Birgel, D., Bach, W., Richoz, S., Smrzka, D., Grasemann, B., Gier, S., Schleper, C., Rittmann, S.K.M.R., Ko?un, E., Peckmann, J., 2018. Evidence for archaeal methanogenesis within veins at the onshore serpentinite-hosted Chimaera seeps, Turkey. Chemical Geology 483, 567-580. ecosystems are potential sites where life may first have evolved on Earth. Serpentinization reactions produce strongly reducing and highly alkaline fluids that are typified by high concentrations of molecular hydrogen (H2) and methane (CH4), which can be used as an energy source by chemosynthetic life. Low-temperature serpentinization at slow-spreading mid-ocean ridges provides an ideal environment for rich microbial communities. Similar environments have also been discovered on land, where present-day low temperature serpentinization occurs during the circulation of groundwater through exposed ophiolites, triggering the production of CH4 and H2, as well as the precipitation of secondary carbonate minerals. The rock samples analyzed here are from the Chimaera seeps in Turkey, representing serpentinized peridotites that are cross-cut by veins composed of brucite and hydromagnesite. Hydromagnesite features a mean δ13C value of ?19.8‰ caused by kinetic isotope fractionation during air-groundwater exchange of CO2, followed by CO2 hydroxylation to bicarbonate within the groundwater. Geochemical modeling revealed that mixing of Mg- and Ca-rich groundwaters is required for hydromagnesite formation at the expense of brucite. Within the carbonate-hydroxide veins the lipid biomarkers pentamethylicosane (PMI) and squalane with δ13C values of +10‰ and +14‰, respectively, and unsaturated derivatives thereof were identified. Archaeol, sn2-hydroxyarchaeol, and sn3-hydroxyarchaeol are other prominent archaeal biomarkers in the veins, also revealing high δ13C values from +6 to +13‰. These isotope patterns combined with the absence of crocetane – a biomarker for methanotrophic archaea – reveal that the microbial communities of the Chimaera seeps performed methanogenesis from a CO2-limited pool rather than methanotrophy. Moreover, bacterial dialkyl glycerol diethers (DAGEs) with unusually high δ13C values (?9 to ?2‰) and minor monoalkyl glycerol monoethers (MAGEs) were identified, suggesting that bacterial sulfate reduction is also active at the Chimaera site. This study reveals that archaeal methanogenesis and bacterial sulfate reduction may be prominent at onshore peridotite-hosted sites, and that biogenic CH4 may contribute to abiotic CH4 emissions from terrestrial seeps. ................
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