Eaogorg.files.wordpress.com



GEOCHEMISTRY ARTICLES – February 2018?Analytical ChemistryAl-Rifai, A.a., Aqel, A., Wahibi, L.A., Alothman, Z.A., Badjah-Hadj-Ahmed, A.-Y., 2018. Carbon nanotube-based benzyl polymethacrylate composite monolith as a solid phase extraction adsorbent and a stationary phase material for simultaneous extraction and analysis of polycyclic aromatic hydrocarbon in water. Journal of Chromatography A 1535, 17-26.Cavalcante, C., de Oliveira, J.P., Hamada, J., de Siqueira, F.A., Nascimento, A.N.d., 2018. Sequential extraction procedure for the separation of Ni and V species in crude oil and analysis by ETAAS, GC–MS, and IR. Fuel 220, 631-637.Chakravarthy, R., Paramati, M., Savalia, A., Verma, A., Das, A.K., Saravanan, C., Gudasi, K.B., 2018. Sulfur and total carboxylic acid number determination in vacuum gas oil by attenuated total reflectance Fourier transform infrared spectroscopy. Energy & Fuels 32, 2128–2136.Cui, C., Fearn, T., 2018. Hierarchical mixture of linear regressions for multivariate spectroscopic calibration: An application for NIR calibration. Chemometrics and Intelligent Laboratory Systems 174, 1-14.Gottschall, T., Meyer, T., Schmitt, M., Popp, J., Limpert, J., Tünnermann, A., 2018. Advances in laser concepts for multiplex, coherent Raman scattering micro-spectroscopy and imaging. TrAC Trends in Analytical Chemistry 102, 103-109.Singer, P.M., Chen, Z., Alemany, L.B., Hirasaki, G.J., Zhu, K., Xie, Z.H., Vo, T.D., 2018. Interpretation of NMR relaxation in bitumen and organic shale using polymer–heptane mixes. Energy & Fuels 32, 1534-1549.Voeten, R.L.C., Ventouri, I.K., Haselberg, R., Somsen, G.W., 2018. Capillary electrophoresis: Trends and recent advances. Analytical Chemistry 90, 1464-1481.Wilkins, R.W.T., Sherwood, N., Li, Z., 2018. RaMM (Raman maturity method) study of samples used in an interlaboratory exercise on a standard test method for determination of vitrinite reflectance on dispersed organic matter in rocks. Marine and Petroleum Geology 91, 236-250.Xu, J., Liu, X., Wang, Q., Huang, S., Yin, L., Xu, J., Liu, X., Jiang, R., Zhu, F., Ouyang, G., 2018. Improving the sensitivity of solid-phase microextraction by reducing the volume of off-line elution solvent. Analytical Chemistry 90, 1572-1577.Gas Chromatography/GC×GC/GC-MSAitken, C.M., Head, I.M., Jones, D.M., Rowland, S.J., Scarlett, A.G., West, C.E., 2018. Comprehensive two-dimensional gas chromatography-mass spectrometry of complex mixtures of anaerobic bacterial metabolites of petroleum hydrocarbons. Journal of Chromatography A 1536, 96-109.Alexandrino, G.L., de Sousa Júnior, G.R., de A.M. Reis, F., Augusto, F., 2018. Optimizing loop-type cryogenic modulation in comprehensive two-dimensional gas chromatography using time-variable combination of the dual-stage jets for analysis of crude oil. Journal of Chromatography A 1536, 82-87.Blumberg, L.M., 2018. Flow optimization in one-dimensional and comprehensive two-dimensional gas chromatography. Journal of Chromatography A 1536, 27-38.Bowman, D.T., Jobst, K.J., Ortiz, X., Reiner, E.J., Warren, L.A., McCarry, B.E., Slater, G.F., 2018. Improved coverage of naphthenic acid fraction compounds by comprehensive two-dimensional gas chromatography coupled with high resolution mass spectrometry. Journal of Chromatography A 1536, 88-95.Brits, M., Gorst-Allman, P., Rohwer, E.R., De Vos, J., de Boer, J., Weiss, J.M., 2018. Comprehensive two-dimensional gas chromatography coupled to high resolution time-of-flight mass spectrometry for screening of organohalogenated compounds in cat hair. Journal of Chromatography A 1536, 151-162.Coutinho, D.M., Fran?a, D., Vanini, G., Mendes, L.A.N., Gomes, A.O., Pereira, V.B., ?vila, B.M.F., Azevedo, D.A., 2018. Rapid hydrocarbon group-type semi-quantification in crude oils by comprehensive two-dimensional gas chromatography. Fuel 220, 379-388.Cuzuel, V., Sizun, A., Cognon, G., Rivals, I., Heulard, F., Thiébaut, D., Vial, J., 2018. Human odor and forensics. Optimization of a comprehensive two-dimensional gas chromatography method based on orthogonality: How not to choose between criteria. Journal of Chromatography A 1536, 58-66.Escobar-Arnanz, J., Mekni, S., Blanco, G., Eljarrat, E., Barceló, D., Ramos, L., 2018. Characterization of organic aromatic compounds in soils affected by an uncontrolled tire landfill fire through the use of comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry. Journal of Chromatography A 1536, 163-175.Freye, C.E., Moore, N.R., Synovec, R.E., 2018. Enhancing the chemical selectivity in discovery-based analysis with tandem ionization time-of-flight mass spectrometry detection for comprehensive two-dimensional gas chromatography. Journal of Chromatography A 1537, 99-108.Kolomnikov, I.G., Efremov, A.M., Tikhomirova, T.I., Sorokina, N.M., Zolotov, Y.A., 2018. Early stages in the history of gas chromatography. Journal of Chromatography A 1537, 109-117.Liang, Z., Chen, L., Alam, M.S., Zeraati Rezaei, S., Stark, C., Xu, H., Harrison, R.M., 2018. Comprehensive chemical characterization of lubricating oils used in modern vehicular engines utilizing GC?×?GC-TOFMS. Fuel 220, 792-799.Lipok, C., Hippler, J., Schmitz, O.J., 2018. A four dimensional separation method based on continuous heart-cutting gas chromatography with ion mobility and high resolution mass spectrometry. Journal of Chromatography A 1536, 50-57.Magagna, F., Liberto, E., Reichenbach, S.E., Tao, Q., Carretta, A., Cobelli, L., Giardina, M., Bicchi, C., Cordero, C., 2018. Advanced fingerprinting of high-quality cocoa: Challenges in transferring methods from thermal to differential-flow modulated comprehensive two dimensional gas chromatography. Journal of Chromatography A 1536, 122-136.Novaes, F.J.M., Kulsing, C., Bizzo, H.R., de Aquino Neto, F.R., Rezende, C.M., Marriott, P.J., 2018. Analysis of underivatised low volatility compounds by comprehensive two-dimensional gas chromatography with a short primary column. Journal of Chromatography A 1536, 75-81.Ntlhokwe, G., Muller, M., Joubert, E., Tredoux, A.G.J., de Villiers, A., 2018. Detailed qualitative analysis of honeybush tea (Cyclopia spp.) volatiles by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry and relation with sensory data. Journal of Chromatography A 1536, 137-150.Parsons, B.A., Pinkerton, D.K., Synovec, R.E., 2018. Implications of phase ratio for maximizing peak capacity in comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry. Journal of Chromatography A 1536, 16-26.Polidoro, A.d.S., Scapin, E., Lazzari, E., Silva, A.N., dos Santos, A.L., Caram?o, E.B., Jacques, R.A., 2018. Valorization of coffee silverskin industrial waste by pyrolysis: From optimization of bio-oil production to chemical characterization by GC?×?GC/qMS. Journal of Analytical and Applied Pyrolysis 129, 43-52.Prodhan, M.A.I., Yin, X., Kim, S., McClain, C., Zhang, X., 2018. Surface fitting for calculating the second dimension retention index in comprehensive two-dimensional gas chromatography mass spectrometry. Journal of Chromatography A 1539, 62-70.Rodrigues, ?.V.A., Silva, S.R.C., Rom?o, W., Castro, E.V.R., Filgueiras, P.R., 2018. Determination of crude oil physicochemical properties by high-temperature gas chromatography associated with multivariate calibration. Fuel 220, 389-395.Seeley, J.V., Schimmel, N.E., Seeley, S.K., 2018. The multi-mode modulator: A versatile fluidic device for two-dimensional gas chromatography. Journal of Chromatography A 1536, 6-15.Sharif, K.M., Kulsing, C., Junior, A.I.d.S., Marriott, P.J., 2018. Second dimension column ensemble pressure tuning in comprehensive two-dimensional gas chromatography. Journal of Chromatography A 1536, 39-49.Titaley, I.A., Ogba, O.M., Chibwe, L., Hoh, E., Cheong, P.H.Y., Simonich, S.L.M., 2018. Automating data analysis for two-dimensional gas chromatography/time-of-flight mass spectrometry non‐targeted analysis of comparative samples. Journal of Chromatography A 1541, 57-62.Tranchida, P.Q., 2018. Comprehensive two-dimensional gas chromatography: A perspective on processes of modulation. Journal of Chromatography A 1536, 2-5.Veenaas, C., Haglund, P., 2018. A retention index system for comprehensive two-dimensional gas chromatography using polyethylene glycols. Journal of Chromatography A 1536, 67-74.Xu, B., Zhang, L., Ma, F., Zhang, W., Wang, X., Zhang, Q., Luo, D., Ma, H., Li, P., 2018. Determination of free steroidal compounds in vegetable oils by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry. Food Chemistry 245, 415-425.Yan, D., Wong, Y.F., Tedone, L., Shellie, R.A., Marriott, P.J., Whittock, S.P., Koutoulis, A., 2018. Chemotyping of new hop (Humulus lupulus L.) genotypes using comprehensive two-dimensional gas chromatography with quadrupole accurate mass time-of-flight mass spectrometry. Journal of Chromatography A 1536, 110-121.Imagine: SEM, TEM, HIM, AFMBai, C., Yu, B., Liu, H., Xie, Z., Han, S., Zhang, L., Ye, R., Ge, J., 2018. The genesis and evolution of carbonate minerals in shale oil formations from Dongying depression, Bohai Bay Basin, China. International Journal of Coal Geology 189, 8-26.Brodie, M.W., Aplin, A.C., Hart, B., Orland, I.J., Valley, J.W., Boyce, A.J., 2018. Oxygen isotope microanalysis by secondary ion mass spectrometry suggests continuous 300-million-year history of calcite cementation and dolomitization in the Devonian Bakken Formation. Journal of Sedimentary Research 88, 91-104.Dhami, N.K., Mukherjee, A., Watkin, E.L.J., 2018. Microbial diversity and mineralogical-mechanical properties of calcitic cave speleothems in natural and in vitro biomineralization conditions. Frontiers in Microbiology 9, 40. doi: 10.3389/fmicb.2018.00040.Dijkstra, N., Hagens, M., Egger, M., Slomp, C.P., 2018. Post-depositional formation of vivianite-type minerals alters sediment phosphorus records. Biogeosciences 15, 861-883.Du, Y., Sang, S., Wang, W., Liu, S., Wang, T., Fang, H., 2018. Experimental study of the reactions of supercritical CO2 and minerals in high-rank coal under formation conditions. Energy & Fuels 32, 1115-1125.Eskelsen, J.R., Xu, J., Chiu, M., Moon, J.-W., Wilkins, B., Graham, D.E., Gu, B., Pierce, E.M., 2018. Influence of structural defects on biomineralized ZnS nanoparticle dissolution: An in-situ electron microscopy study. Environmental Science & Technology 52, 1139-1149.Gonzalez-Pimentel, J.L., Miller, A.Z., Jurado, V., Laiz, L., Pereira, M.F.C., Saiz-Jimenez, C., 2018. Yellow coloured mats from lava tubes of La Palma (Canary Islands, Spain) are dominated by metabolically active Actinobacteria. Scientific Reports 8, Article 1944.Gubernat, M., Fraczek-Szczypta, A., Tomala, J., Blazewicz, S., 2018. Catalytic effect of montmorillonite nanoparticles on thermal decomposition of coal tar pitch to carbon. Journal of Analytical and Applied Pyrolysis 130, 90-98.Guo, H., He, R., Jia, W., Peng, P.a., Lei, Y., Luo, X., Wang, X., Zhang, L., Jiang, C., 2018. Pore characteristics of lacustrine shale within the oil window in the Upper Triassic Yanchang Formation, southeastern Ordos Basin, China. Marine and Petroleum Geology 91, 279-296.Hao, Z., Bechtel, H.A., Kneafsey, T., Gilbert, B., Nico, P.S., 2018. Cross-scale molecular analysis of chemical heterogeneity in shale rocks. Scientific Reports 8, Article 2552.Howes, S.C., Koning, R.I., Koster, A.J., 2018. Correlative microscopy for structural microbiology. Current Opinion in Microbiology 43, 132-138.Jung, P., Briegel-Williams, L., Simon, A., Thyssen, A., Büdel, B., 2018. Uncovering biological soil crusts: carbon content and structure of intact Arctic, Antarctic and alpine biological soil crusts. Biogeosciences 15, 1149-1160.Liu, S., Wang, Z., Zhang, L., 2018. Experimental study on the cracking process of layered shale using X-ray microCT. Energy Exploration & Exploitation 36, 297-313.Morga, R., Pawlyta, M., 2018. Microstructure of graptolite periderm in Silurian gas shales of Northern Poland. International Journal of Coal Geology 189, 1-7.Pan, Y., Hui, D., Luo, P., Zhang, Y., Sun, L., Wang, K., 2018. Experimental investigation of the geochemical interactions between supercritical CO2 and shale: Implications for CO2 storage in gas-bearing shale formations. Energy & Fuels 32, 1963-1978.Qiu, X., Yao, Y., Wang, H., Duan, Y., 2018. Live microbial cells adsorb Mg2+ more effectively than lifeless organic matter. Frontiers of Earth Science 12, 160-169.Stuckey, J.W., Goodwin, C., Wang, J., Kaplan, L.A., Vidal-Esquivel, P., Beebe, T.P., Sparks, D.L., 2018. Impacts of hydrous manganese oxide on the retention and lability of dissolved organic matter. Geochemical Transactions 19, Article 6.Sundaram, S., Thakur, I.S., 2018. Induction of calcite precipitation through heightened production of extracellular carbonic anhydrase by CO2 sequestering bacteria. Bioresource Technology 253, 368-371.Taheri-Shakib, J., Shekarifard, A., Naderi, H., 2018. Analysis of the asphaltene properties of heavy crude oil under ultrasonic and microwave irradiation. Journal of Analytical and Applied Pyrolysis 129, 171-180.Terlier, T., Lee, J., Lee, K., Lee, Y., 2018. Improvement of the correlative AFM and ToF-SIMS approach using an empirical sputter model for 3DS chemical characterization. Analytical Chemistry 90, 1701-1709.Wacey, D., Urosevic, L., Saunders, M., George, A.D., 2018. Mineralisation of filamentous cyanobacteria in Lake Thetis stromatolites, Western Australia. Geobiology 16, 203-215.Yang, S., Chen, G., Lv, C., Li, C., Yin, N., Yang, F., Xue, L., 2018. Evolution of nanopore structure in lacustrine organic-rich shales during thermal maturation from hydrous pyrolysis, Minhe Basin, Northwest China. Energy Exploration & Exploitation 36, 265-281.Zhang, K., Guo, Y., Bai, G., Wang, Z., Fan, B., Wu, J., Niu, X., 2018. Pore-structure characterization of the Eocene Sha-3 sandstones in the Bohai Bay Basin, China. Energy & Fuels 32, 1579-1591.Zhang, L., Zhang, Y., Gamal El-Din, M., 2018. Degradation of recalcitrant naphthenic acids from raw and ozonated oil sands process-affected waters by a semi-passive biofiltration process. Water Research 133, 310-318.Imagine: Xray CTCallow, B., Falcon-Suarez, I., Ahmed, S., Matter, J., 2018. Assessing the carbon sequestration potential of basalt using X-ray micro-CT and rock mechanics. International Journal of Greenhouse Gas Control 70, 146-156.Carrel, M., Morales, V.L., Beltran, M.A., Derlon, N., Kaufmann, R., Morgenroth, E., Holzner, M., 2018. Biofilms in 3D porous media: Delineating the influence of the pore network geometry, flow and mass transfer on biofilm development. Water Research 134, 280-291.Chen, X., Verma, R., Espinoza, D.N., Prodanovi?, M., 2018. Pore-scale determination of gas relative permeability in hydrate-bearing sediments using X-ray computed micro-tomography and lattice Boltzmann method. Water Resources Research 54, 600-608.Gonzalez-Pimentel, J.L., Miller, A.Z., Jurado, V., Laiz, L., Pereira, M.F.C., Saiz-Jimenez, C., 2018. Yellow coloured mats from lava tubes of La Palma (Canary Islands, Spain) are dominated by metabolically active Actinobacteria. Scientific Reports 8, Article 1944.Islam, A., Chevalier, S., Sassi, M., 2018. Structural characterization and numerical simulations of flow properties of standard and reservoir carbonate rocks using micro-tomography. Computers & Geosciences 113, 14-22.Liu, S., Wang, Z., Zhang, L., 2018. Experimental study on the cracking process of layered shale using X-ray microCT. Energy Exploration & Exploitation 36, 297-313.Mehra, A., Maloof, A., 2018. Multiscale approach reveals that Cloudina aggregates are detritus and not in situ reef constructions. Proceedings of the National Academy of Sciences.Wang, J., Zhang, L., Zhao, J., Ai, L., Yang, L., 2018. Variations in permeability along with interfacial tension in hydrate-bearing porous media. Journal of Natural Gas Science and Engineering 51, 141-146.Wang, S., Yang, P., Yang, Z., 2018. Characterization of freeze–thaw effects within clay by 3D X-ray Computed Tomography. Cold Regions Science and Technology 148, 13-21.Zeng, F., Guo, J., Ma, S., Chen, Z., 2018. 3D observations of the hydraulic fracturing process for a model non-cemented horizontal well under true triaxial conditions using an X-ray CT imaging technique. Journal of Natural Gas Science and Engineering 52, 128-140.Zhou, H.W., Zhong, J.C., Ren, W.G., Wang, X.Y., Yi, H.Y., 2018. Characterization of pore-fracture networks and their evolution at various measurement scales in coal samples using X-ray μCT and a fractal method. International Journal of Coal Geology 189, 35-49.Liquid Chromatography/LC-MS/SFCBeňo, E., Góra, R., Hutta, M., 2018. Development of a precolumn derivatization HPLC method with diode-array detection for the determination of amino sugars in peat and soil humic acids. Journal of Separation Science 41, 814-821.Cao, J.-L., Wang, S.-S., Hu, H., He, C.-W., Wan, J.-B., Su, H.-X., Wang, Y.-T., Li, P., 2018. Online comprehensive two-dimensional hydrophilic interaction chromatography × reversed-phase liquid chromatography coupled with hybrid linear ion trap Orbitrap mass spectrometry for the analysis of phenolic acids in Salvia miltiorrhiza. Journal of Chromatography A 1536, 216-227.Davis, J.M., Stoll, D.R., 2018. Likelihood of total resolution in selective comprehensive two-dimensional liquid chromatography with parallel processing: Simulation and theory. Journal of Chromatography A 1537, 43-57.Desfontaine, V., Capetti, F., Nicoli, R., Kuuranne, T., Veuthey, J.-L., Guillarme, D., 2018. Systematic evaluation of matrix effects in supercritical fluid chromatography versus liquid chromatography coupled to mass spectrometry for biological samples. Journal of Chromatography B 1079, 51-61.Gst?ttner, C., Klemm, D., Haberger, M., Bathke, A., Wegele, H., Bell, C., Kopf, R., 2018. Fast and automated characterization of antibody variants with 4D HPLC/MS. Analytical Chemistry 90, 2119-2125.Halvorson, J., Lenhoff, A.M., Dittmann, M., Stoll, D.R., 2018. Implications of turbulent flow in connecting capillaries used in high performance liquid chromatography. Journal of Chromatography A 1536, 185-194.Helmueller, S.C., Poe, D.P., Kaczmarski, K., 2018. Adiabatic packed column supercritical fluid chromatography using a dual-zone still-air column heater. Journal of Chromatography A 1535, 141-153.Hu, M., Müller, E., Schymanski, E.L., Ruttkies, C., Schulze, T., Brack, W., Krauss, M., 2018. Performance of combined fragmentation and retention prediction for the identification of organic micropollutants by LC-HRMS. Analytical and Bioanalytical Chemistry 410, 1931-1941.Iguiniz, M., Rouvière, F., Corbel, E., Roques, N., Heinisch, S., 2018. Comprehensive two dimensional liquid chromatography as analytical strategy for pharmaceutical analysis. Journal of Chromatography A 1536, 195-204.Montero, L., Sáez, V., von Baer, D., Cifuentes, A., Herrero, M., 2018. Profiling of Vitis vinifera L. canes (poly)phenolic compounds using comprehensive two-dimensional liquid chromatography. Journal of Chromatography A 1536, 205-215.Nannou, C.I., Boti, V.I., Albanis, T.A., 2018. Trace analysis of pesticide residues in sediments using liquid chromatography–high-resolution Orbitrap mass spectrometry. Analytical and Bioanalytical Chemistry 410, 1977-1989.Patriarca, C., Bergquist, J., Sj?berg, P.J.R., Tranvik, L., Hawkes, J.A., 2018. Online HPLC-ESI-HRMS method for the analysis and comparison of different dissolved organic matter samples. Environmental Science & Technology 52, 2091-2099.Petkovic, O., Guibal, P., Sassiat, P., Vial, J., Thiébaut, D., 2018. Active modulation in neat carbon dioxide packed column comprehensive two-dimensional supercritical fluid chromatography. Journal of Chromatography A 1536, 176-184.Sandron, S., Davies, N.W., Wilson, R., Cardona, A.R., Haddad, P.R., Nesterenko, P.N., Paull, B., 2018. Fractionation of dissolved organic matter on coupled reversed-phase monolithic columns and characterisation using reversed-phase liquid chromatography-high resolution mass spectrometry. Chromatographia 81, 203-213.Schirone, M., Berti, M., Visciano, P., Chiumiento, F., Migliorati, G., Tofalo, R., Suzzi, G., Di Giacinto, F., Ferri, N., 2018. Determination of lipophilic marine biotoxins in mussels harvested from the Adriatic Sea by LC-MS/MS. Frontiers in Microbiology 9, 152. doi: 110.3389/fmicb.2018.00152.Shen, X., Chang, H., Sun, D., Wang, L., Wu, F., 2018. Trace analysis of 61 natural and synthetic progestins in river water and sewage effluents by ultra-high performance liquid chromatography–tandem mass spectrometry. Water Research 133, 142-152.Sun, M., Sandahl, M., Turner, C., 2018. Comprehensive on-line two-dimensional liquid chromatography?×?supercritical fluid chromatography with trapping column-assisted modulation for depolymerised lignin analysis. Journal of Chromatography A 1541, 21-30.Wen, Y., Talebi, M., Amos, R.I.J., Szucs, R., Dolan, J.W., Pohl, C.A., Haddad, P.R., 2018. Retention prediction in reversed phase high performance liquid chromatography using quantitative structure-retention relationships applied to the Hydrophobic Subtraction Model. Journal of Chromatography A 1541, 1-11.Mass Spectroscopy/ICR-FTMS/OrbitrapCao, J.-L., Wang, S.-S., Hu, H., He, C.-W., Wan, J.-B., Su, H.-X., Wang, Y.-T., Li, P., 2018. Online comprehensive two-dimensional hydrophilic interaction chromatography × reversed-phase liquid chromatography coupled with hybrid linear ion trap Orbitrap mass spectrometry for the analysis of phenolic acids in Salvia miltiorrhiza. Journal of Chromatography A 1536, 216-227.Chance, R.J., Hamilton, J.F., Carpenter, L.J., Hackenberg, S.C., Andrews, S.J., Wilson, T.W., 2018. Water-soluble organic composition of the Arctic Sea surface microlayer and association with ice nucleation ability. Environmental Science & Technology 52, 1817-1826.Chen, B., OuYang, C., Tian, Z., Xu, M., Li, L., 2018. A high resolution atmospheric pressure matrix-assisted laser desorption/ionization-quadrupole-Orbitrap MS platform enables in situ analysis of biomolecules by multi-mode ionization and acquisition. Analytica Chimica Acta 1007, 16-25.Coward, E.K., Ohno, T., Plante, A.F., 2018. Adsorption and molecular fractionation of dissolved organic matter on iron-bearing mineral matrices of varying crystallinity. Environmental Science & Technology 52, 1036-1044.Han, Y., Zhang, Y., Xu, C., Hsu, C.S., 2018. Molecular characterization of sulfur-containing compounds in petroleum. Fuel 221, 144-158.Hebert, A.S., Th?ing, C., Riley, N.M., Kwiecien, N.W., Shiskova, E., Huguet, R., Cardasis, H.L., Kuehn, A., Eliuk, S., Zabrouskov, V., Westphall, M.S., McAlister, G.C., Coon, J.J., 2018. Improved precursor characterization for data-dependent mass spectrometry. Analytical Chemistry 90, 2333-2340.Heuillet, M., Bellvert, F., Cahoreau, E., Letisse, F., Millard, P., Portais, J.-C., 2018. Methodology for the validation of isotopic analyses by mass spectrometry in stable-isotope labeling experiments. Analytical Chemistry 90, 1852-1860.Hu, M., Müller, E., Schymanski, E.L., Ruttkies, C., Schulze, T., Brack, W., Krauss, M., 2018. Performance of combined fragmentation and retention prediction for the identification of organic micropollutants by LC-HRMS. Analytical and Bioanalytical Chemistry 410, 1931-1941.Hur, M., Ware, R.L., Park, J., McKenna, A.M., Rodgers, R.P., Nikolau, B.J., Wurtele, E.S., Marshall, A.G., 2018. Statistically significant differences in composition of petroleum crude oils revealed by volcano plots generated from ultrahigh resolution Fourier transform ion cyclotron resonance mass spectra. Energy & Fuels 32, 1206-1212.Khodjaniyazova, S., Nazari, M., Garrard, K.P., Matos, M.P.V., Jackson, G.P., Muddiman, D.C., 2018. Characterization of the spectral accuracy of an Orbitrap mass analyzer using isotope ratio mass spectrometry. Analytical Chemistry 90, 1897-1906.Krajewski, L.C., Lobodin, V.V., Johansen, C., Bartges, T.E., Maksimova, E.V., MacDonald, I.R., Marshall, A.G., 2018. Linking natural oil seeps from the Gulf of Mexico to their origin by use of Fourier transform ion cyclotron resonance mass spectrometry. Environmental Science & Technology 52, 1365-1374.Nannou, C.I., Boti, V.I., Albanis, T.A., 2018. Trace analysis of pesticide residues in sediments using liquid chromatography–high-resolution Orbitrap mass spectrometry. Analytical and Bioanalytical Chemistry 410, 1977-1989.Nowak, J.A., Shrestha, P.M., Weber, R.J., McKenna, A.M., Chen, H., Coates, J.D., Goldstein, A.H., 2018. Comprehensive analysis of changes in crude oil chemical composition during biosouring and treatments. Environmental Science & Technology 52, 1290-1300.Pudenzi, M.A., Santos, J.M., Wisniewski, A., Eberlin, M.N., 2018. Comprehensive characterization of asphaltenes by Fourier transform ion cyclotron resonance mass spectrometry precipitated under different n-alkanes solvents. Energy & Fuels 32, 1038-1046.Retelletti Brogi, S., Ha, S.-Y., Kim, K., Derrien, M., Lee, Y.K., Hur, J., 2018. Optical and molecular characterization of dissolved organic matter (DOM) in the Arctic ice core and the underlying seawater (Cambridge Bay, Canada): Implication for increased autochthonous DOM during ice melting. Science of The Total Environment 627, 802-811.Roullier-Gall, C., Signoret, J., Hemmler, D., Witting, M.A., Kanawati, B., Sch?fer, B., Gougeon, R.D., Schmitt-Kopplin, P., 2018. Usage of FT-ICR-MS metabolomics for characterizing the chemical signatures of barrel-aged whisky. Frontiers in Chemistry 6, 29. doi: 10.3389/fchem.2018.00029.Smith, D.F., Podgorski, D.C., Rodgers, R.P., Blakney, G.T., Hendrickson, C.L., 2018. 21 Tesla FT-ICR mass spectrometer for ultrahigh-resolution analysis of complex organic mixtures. Analytical Chemistry 90, 2041-2047.Stavitskaya, A.V., Konstantinova, M.L., Razumovskii, S.D., Safieva, R.Z., Vinokurov, V.A., 2017. Analysis of sour oil ozonation products by ultra-high resolution mass-spectrometry. Petroleum Chemistry 57, 1012-1017.Zhang, H., Yang, M., 2018. Characterization of brominated disinfection byproducts formed during chloramination of fulvic acid in the presence of bromide. Science of The Total Environment 627, 118-124.Mass Spectroscopy/OtherDuncan, K.D., Lanekoff, I., 2018. Oversampling to improve spatial resolution for liquid extraction mass spectrometry imaging. Analytical Chemistry 90, 2451-2455.Filla, R.T., Schrell, A.M., Coulton, J.B., Edwards, J.L., Roper, M.G., 2018. Frequency-modulated continuous flow analysis electrospray ionization mass spectrometry (FM-CFA-ESI-MS) for sample multiplexing. Analytical Chemistry 90, 2414-2419.Fouquet, T., Satoh, T., Sato, H., 2018. First gut instincts are always right: The resolution required for a mass defect analysis of polymer ions can be as low as oligomeric. Analytical Chemistry 90, 2404-2408.Gaudreau, A.M., Labrie, J., Goetz, C., Dufour, S., Jacques, M., 2018. Evaluation of MALDI-TOF mass spectrometry for the identification of bacteria growing as biofilms. Journal of Microbiological Methods 145, 79-81.Hale, O.J., Cramer, R., 2018. Collision-induced dissociation of doubly-charged barium-cationized lipids generated from liquid samples by atmospheric pressure matrix-assisted laser desorption/ionization provides structurally diagnostic product ions. Analytical and Bioanalytical Chemistry 410, 1435-1444.Hebert, A.S., Th?ing, C., Riley, N.M., Kwiecien, N.W., Shiskova, E., Huguet, R., Cardasis, H.L., Kuehn, A., Eliuk, S., Zabrouskov, V., Westphall, M.S., McAlister, G.C., Coon, J.J., 2018. Improved precursor characterization for data-dependent mass spectrometry. Analytical Chemistry 90, 2333-2340.Koolen, H.H.F., Gomes, A.F., de Moura, L.G.M., Marcano, F., Cardoso, F.M.R., Klitzke, C.F., Wojcik, R., Binkley, J., Patrick, J.S., Swarthout, R.F., Rosa, P.T.V., Gozzo, F.C., 2018. Integrative mass spectrometry strategy for fingerprinting and tentative structural characterization of asphaltenes. Fuel 220, 717-724.Robinson, K.N., Steven, R.T., Bunch, J., 2018. Matrix optical absorption in UV-MALDI MS. Journal of The American Society for Mass Spectrometry 29, 501-511.Sj?vall, P., Pomerantz, A.E., Lu, X., Mullins, O.C., 2018. Time of flight-secondary ion mass spectrometry (TOF-SIMS) study of diverse asphaltenes. Fuel 220, 638-644.Tascon, M., Alam, M.N., Gómez-Ríos, G.A., Pawliszyn, J., 2018. Development of a microfluidic open interface with flow isolated desorption volume for the direct coupling of SPME devices to mass spectrometry. Analytical Chemistry 90, 2631-2638.Terlier, T., Lee, J., Lee, K., Lee, Y., 2018. Improvement of the correlative AFM and ToF-SIMS approach using an empirical sputter model for 3DS chemical characterization. Analytical Chemistry 90, 1701-1709.Tuccitto, N., Capizzi, G., Torrisi, A., Licciardello, A., 2018. Unsupervised analysis of big ToF-SIMS data sets: A statistical pattern recognition approach. Analytical Chemistry 90, 2860-2866.Van Nuffel, S., Elie, N., Yang, E., Nouet, J., Touboul, D., Chaurand, P., Brunelle, A., 2018. Insights into the MALDI process after matrix deposition by sublimation using 3D ToF-SIMS imaging. Analytical Chemistry 90, 1907-1914.Zhan, L., Xie, X., Li, Y., Liu, H., Xiong, C., Nie, Z., 2018. Differentiation and relative quantitation of disaccharide isomers by MALDI-TOF/TOF mass spectrometry. Analytical Chemistry 90, 1525-1530.Metabolomics/LipidomicsBarrilero, R., Gil, M., Amigó, N., Dias, C.B., Wood, L.G., Garg, M.L., Ribalta, J., Heras, M., Vinaixa, M., Correig, X., 2018. LipSpin: A new bioinformatics tool for quantitative 1H NMR lipid profiling. Analytical Chemistry 90, 2031-2040.Barupal, D.K., Fan, S., Fiehn, O., 2018. Integrating bioinformatics approaches for a comprehensive interpretation of metabolomics datasets. Current Opinion in Biotechnology 54, 1-9.Date, Y., Kikuchi, J., 2018. Application of a deep neural network to metabolomics studies and its performance in determining important variables. Analytical Chemistry 90, 1805-1810.Harris, R.A., May, J.C., Stinson, C.A., Xia, Y., McLean, J.A., 2018. Determining double bond position in lipids using online ozonolysis coupled to liquid chromatography and ion mobility-mass spectrometry. Analytical Chemistry 90, 1915-1924.Pittera, J., Jouhet, J., Breton, S., Garczarek, L., Partensky, F., Maréchal, ?., Nguyen, N.A., Doré, H., Ratin, M., Pitt, F.D., Scanlan, D.J., Six, C., 2018. Thermoacclimation and genome adaptation of the membrane lipidome in marine Synechococcus. Environmental Microbiology 20, 612-631.R?hnisch, H.E., Eriksson, J., Müllner, E., Agback, P., Sandstr?m, C., Moazzami, A.A., 2018. AQuA: An automated quantification algorithm for high-throughput NMR-based metabolomics and its application in human plasma. Analytical Chemistry 90, 2095-2102.Roullier-Gall, C., Signoret, J., Hemmler, D., Witting, M.A., Kanawati, B., Sch?fer, B., Gougeon, R.D., Schmitt-Kopplin, P., 2018. Usage of FT-ICR-MS metabolomics for characterizing the chemical signatures of barrel-aged whisky. Frontiers in Chemistry 6, 29. doi: 10.3389/fchem.2018.00029.Tian, Z., Vila, J., Yu, M., Bodnar, W., Aitken, M.D., 2018. Tracing the biotransformation of polycyclic aromatic hydrocarbons in contaminated soil using stable isotope-assisted metabolomics. Environmental Science & Technology Letters 5, 103-109.Tsugawa, H., 2018. Advances in computational metabolomics and databases deepen the understanding of metabolisms. Current Opinion in Biotechnology 54, 10-17.PuppyomicsDuranton, C., Bedossa, T., Gaunet, F., 2018. Pet dogs synchronize their walking pace with that of their owners in open outdoor areas. Animal Cognition 21, 219-226.Archaeological/Art Organic ChemistryDevièse, T., Van Ham-Meert, A., Hare, V.J., Lundy, J., Hommel, P., Ivanovich Bazaliiskii, V., Orton, J., 2018. Supercritical fluids for higher extraction yields of lipids from archeological ceramics. Analytical Chemistry 90, 2420-2424.Devièse, T., Van Ham-Meert, A., Hare, V.J., Lundy, J., Hommel, P., Ivanovich Bazaliiskii, V., Orton, J., 2018. Supercritical fluids for higher extraction yields of lipids from archeological ceramics. Analytical Chemistry 90, 2420-2424.Goldman, Y., Linn, R., Shamir, O., Weinstein-Evron, M., 2018. Micro-RTI as a novel technology for the investigation and documentation of archaeological textiles. Journal of Archaeological Science: Reports 19, 1-10.Hannah, E.L., McLaughlin, T.R., Keaveney, E.M., Hakenbeck, S.E., 2018. Anglo-Saxon diet in the Conversion period: A comparative isotopic study using carbon and nitrogen. Journal of Archaeological Science: Reports 19, 24-34.Kidder, T.R., Henry, E.R., Arco, L.J., 2018. Rapid climate change-induced collapse of hunter-gatherer societies in the lower Mississippi River valley between ca. 3300 and 2780 cal yr BP. Science China Earth Sciences 61, 178-189.Milton, C.J., 2018. Geophysics and geochemistry; an interdisciplinary approach to archaeology in wetland contexts. Journal of Archaeological Science: Reports 18, 197-212.Monnier, G., Frahm, E., Luo, B., Missal, K., 2018. Developing FTIR microspectroscopy for the analysis of animal-tissue residues on stone tools. Journal of Archaeological Method and Theory 25, 1-44.Peggie, D.A., Kirby, J., Poulin, J., Genuit, W., Romanuka, J., Wills, D.F., De Simone, A., Hulme, A.N., 2018. Historical mystery solved: a multi-analytical approach to the identification of a key marker for the historical use of brazilwood (Caesalpinia spp.) in paintings and textiles. Analytical Methods 10, 617-623.Price, S.D.R., Keenleyside, A., Schwarcz, H.P., 2018. Testing the validity of stable isotope analyses of dental calculus as a proxy in paleodietary studies. Journal of Archaeological Science 91, 92-103.Roberts, P., Fernandes, R., Craig, O.E., Larsen, T., Lucquin, A., Swift, J., Zech, J., 2018. Calling all archaeologists: guidelines for terminology, methodology, data handling, and reporting when undertaking and reviewing stable isotope applications in archaeology. Rapid Communications in Mass Spectrometry 32, 361-372.Tejero-Andrade, A., Argote-Espino, D.L., Cifuentes-Nava, G., Hernández-Quintero, E., Chávez, R.E., García-Serrano, A., 2018. ‘Illuminating’ the interior of Kukulkan's Pyramid, Chichén Itzá, Mexico, by means of a non-conventional ERT geophysical survey. Journal of Archaeological Science 90, 1-11.V?gene, ?.J., Herbig, A., Campana, M.G., Robles García, N.M., Warinner, C., Sabin, S., Spyrou, M.A., Andrades Valtue?a, A., Huson, D., Tuross, N., Bos, K.I., Krause, J., 2018. Salmonella enterica genomes from victims of a major sixteenth-century epidemic in Mexico. Nature Ecology & Evolution 2, 520–528.Witkowski, B., Duchnowicz, A., Ganeczko, M., Laudy, A., Gierczak, T., Biesaga, M., 2018. Identification of proteins, drying oils, waxes and resins in the works of art micro-samples by chromatographic and mass spectrometric techniques. Journal of Separation Science 41, 630-638.Wu, W., Zheng, H., Hou, M., Ge, Q., 2018. The 5.5 cal ka BP climate event, population growth, circumscription and the emergence of the earliest complex societies in China. Science China Earth Sciences 61, 134-148.BiochemistryCaccamo, P.D., Brun, Y.V., 2018. The molecular basis of noncanonical bacterial morphology. Trends in Microbiology 26, 191-208.Derguine-Mecheri, L., Kebbouche-Gana, S., Khemili-Talbi, S., Djenane, D., 2018. Screening and biosurfactant/bioemulsifier production from a high-salt-tolerant halophilic Cryptococcus strain YLF isolated from crude oil. Journal of Petroleum Science and Engineering 162, 712-724.Howes, S.C., Koning, R.I., Koster, A.J., 2018. Correlative microscopy for structural microbiology. Current Opinion in Microbiology 43, 132-138.Mori, T., Cahn, J.K.B., Wilson, M.C., Meoded, R.A., Wiebach, V., Martinez, A.F.C., Helfrich, E.J.N., Albersmeier, A., Wibberg, D., D?twyler, S., Keren, R., Lavy, A., Rückert, C., Ilan, M., Kalinowski, J., Matsunaga, S., Takeyama, H., Piel, J., 2018. Single-bacterial genomics validates rich and varied specialized metabolism of uncultivated Entotheonella sponge symbionts. Proceedings of the National Academy of Sciences.Seligmann, H., Raoult, D., 2018. Stem-loop RNA hairpins in giant viruses: Invading rRNA-like repeats and a template free RNA. Frontiers in Microbiology 9, 101. doi: 110.3389/fmicb.2018.00101.Shelford, E.J., Suttle, C.A., 2018. Virus-mediated transfer of nitrogen from heterotrophic bacteria to phytoplankton. Biogeosciences 15, 809-819.Zheng, Y., Harris, D.F., Yu, Z., Fu, Y., Poudel, S., Ledbetter, R.N., Fixen, K.R., Yang, Z.-Y., Boyd, E.S., Lidstrom, M.E., Seefeldt, L.C., Harwood, C.S., 2018. A pathway for biological methane production using bacterial iron-only nitrogenase. Nature Microbiology 3, 281-286.BiodegradationAitken, C.M., Head, I.M., Jones, D.M., Rowland, S.J., Scarlett, A.G., West, C.E., 2018. Comprehensive two-dimensional gas chromatography-mass spectrometry of complex mixtures of anaerobic bacterial metabolites of petroleum hydrocarbons. Journal of Chromatography A 1536, 96-109.Birch, H., Hammersh?j, R., Mayer, P., 2018. Determining biodegradation kinetics of hydrocarbons at low concentrations – covering 5 and 9 orders of magnitude of Kow and Kaw. Environmental Science & Technology 52, 2143-2151.Deeba, F., Pruthi, V., Negi, Y.S., 2018. Aromatic hydrocarbon biodegradation activates neutral lipid biosynthesis in oleaginous yeast. Bioresource Technology 255, 273-280.García-Cruz, N.U., Sánchez-Avila, J.I., Valdés-Lozano, D., Gold-Bouchot, G., Aguirre-Macedo, L., 2018. Biodegradation of hexadecane using sediments from rivers and lagoons of the Southern Gulf of Mexico. Marine Pollution Bulletin 128, 202-207.Garrido-Sanz, D., Manzano, J., Martín, M., Redondo-Nieto, M., Rivilla, R., 2018. Metagenomic analysis of a biphenyl-degrading soil bacterial consortium reveals the metabolic roles of specific populations. Frontiers in Microbiology 9, 232. doi: 210.3389/fmicb.2018.00232.Kumari, S., Regar, R.K., Manickam, N., 2018. Improved polycyclic aromatic hydrocarbon degradation in a crude oil by individual and a consortium of bacteria. Bioresource Technology 254, 174-179.Nowak, J.A., Shrestha, P.M., Weber, R.J., McKenna, A.M., Chen, H., Coates, J.D., Goldstein, A.H., 2018. Comprehensive analysis of changes in crude oil chemical composition during biosouring and treatments. Environmental Science & Technology 52, 1290-1300.Scheibye, K., Christensen, J.H., Johnsen, A.R., 2017. Biodegradation of crude oil in Arctic subsurface water from the Disko Bay (Greenland) is limited. Environmental Pollution 223, 73-80.Tian, Z., Vila, J., Yu, M., Bodnar, W., Aitken, M.D., 2018. Tracing the biotransformation of polycyclic aromatic hydrocarbons in contaminated soil using stable isotope-assisted metabolomics. Environmental Science & Technology Letters 5, 103-109.Vergeynst, L., Wegeberg, S., Aamand, J., Lassen, P., Gosewinkel, U., Fritt-Rasmussen, J., Gustavson, K., Mosbech, A., 2018. Biodegradation of marine oil spills in the Arctic with a Greenland perspective. Science of The Total Environment 626, 1243-1258.Biofuels/BiomassChistoserdova, L., 2018. Applications of methylotrophs: can single carbon be harnessed for biotechnology? Current Opinion in Biotechnology 50, 189-194.Guedes, R.E., Luna, A.S., Torres, A.R., 2018. Operating parameters for bio-oil production in biomass pyrolysis: A review. Journal of Analytical and Applied Pyrolysis 129, 134-149.Hossain, G.S., Nadarajan, S.P., Zhang, L., Ng, T.-K., Foo, J.L., Ling, H., Choi, W.J., Chang, M.W., 2018. Rewriting the metabolic blueprint: Advances in pathway diversification in microorganisms. Frontiers in Microbiology 9, 155. doi: 110.3389/fmicb.2018.00155.Huang, Y.-X., Hu, Z., 2018. An integrated electrochemical and biochemical system for sequential reduction of CO2 to methane. Fuel 220, 8-13.Humphreys, C.M., Minton, N.P., 2018. Advances in metabolic engineering in the microbial production of fuels and chemicals from C1 gas. Current Opinion in Biotechnology 50, 174-181.Remmers, I.M., Wijffels, R.H., Barbosa, M.J., Lamers, P.P., 2018. Can we approach theoretical lipid yields in microalgae? Trends in Biotechnology 36, 265-276.Sergeeva, Y.E., Mostova, E.B., Gorin, K.V., Komova, A.V., Konova, I.A., Pojidaev, V.M., Gotovtsev, P.M., Vasilov, R.G., Sineoky, S.P., 2017. Calculation of biodiesel fuel characteristics based on the fatty acid composition of the lipids of some biotechnologically important microorganisms. Applied Biochemistry and Microbiology 53, 807-813.Shrestha, N., Chilkoor, G., Vemuri, B., Rathinam, N., Sani, R.K., Gadhamshetty, V., 2018. Extremophiles for microbial-electrochemistry applications: A critical review. Bioresource Technology 255, 318-330.Yanez, A.J., Natarajan, P., Li, W., Mabon, R., Broadbelt, L.J., 2018. Coupled structural and kinetic model of lignin fast pyrolysis. Energy & Fuels 32, 1822-1830.BiogeochemistryDial, R.J., Ganey, G.Q., Skiles, S.M., 2018. What color should glacier algae be? An ecological role for red carbon in the cryosphere. FEMS Microbiology Ecology 94, Article fiy007.Dijkstra, N., Hagens, M., Egger, M., Slomp, C.P., 2018. Post-depositional formation of vivianite-type minerals alters sediment phosphorus records. Biogeosciences 15, 861-883.Dyksma, S., Pjevac, P., Ovanesov, K., Mussmann, M., 2018. Evidence for H2 consumption by uncultured Desulfobacterales in coastal sediments. Environmental Microbiology 20, 450-461.Fortunato, C.S., Larson, B., Butterfield, D.A., Huber, J.A., 2018. Spatially distinct, temporally stable microbial populations mediate biogeochemical cycling at and below the seafloor in hydrothermal vent fluids. Environmental Microbiology 20, 769-784.Harrison, B.K., Myrbo, A., Flood, B.E., Bailey, J.V., 2018. Abrupt burial imparts persistent changes to the bacterial diversity of turbidite-associated sediment profiles. Geobiology 16, 190-202.Humphreys, M.P., Daniels, C.J., Wolf-Gladrow, D.A., Tyrrell, T., Achterberg, E.P., 2018. On the influence of marine biogeochemical processes over CO2 exchange between the atmosphere and ocean. Marine Chemistry 199, 1-11.Jung, P., Briegel-Williams, L., Simon, A., Thyssen, A., Büdel, B., 2018. Uncovering biological soil crusts: carbon content and structure of intact Arctic, Antarctic and alpine biological soil crusts. Biogeosciences 15, 1149-1160.Lenton, T.M., Daines, S.J., Mills, B.J.W., 2018. COPSE reloaded: An improved model of biogeochemical cycling over Phanerozoic time. Earth-Science Reviews 178, 1-28.Mamet, S.D., Ma, B., Ulrich, A., Schryer, A., Siciliano, S.D., 2018. Who is the rock miner and who is the hunter? The use of heavy-oxygen labeled phosphate (P18O4) to differentiate between C and P fluxes in a benzene-degrading consortium. Environmental Science & Technology 52, 1773-1786.McCrimmon, D.O., Bizimis, M., Holland, A., Ziolkowski, L.A., 2018. Supraglacial microbes use young carbon and not aged cryoconite carbon. Organic Geochemistry 118, 63-72.Molari, M., Guilini, K., Lott, C., Weber, M., de Beer, D., Meyer, S., Ramette, A., Wegener, G., Wenzh?fer, F., Martin, D., Cibic, T., De Vittor, C., Vanreusel, A., Boetius, A., 2018. CO2 leakage alters biogeochemical and ecological functions of submarine sands. Science Advances 4, Article eaao2040.Parker, C.W., Auler, A.S., Barton, M.D., Sasowsky, I.D., Senko, J.M., Barton, H.A., 2018. Fe(III) reducing microorganisms from iron ore caves demonstrate fermentative Fe(III) reduction and promote cave formation. Geomicrobiology Journal 35, 311-322.Pérez-Huerta, A., Coronado, I., Hegna, T.A., 2018. Understanding biomineralization in the fossil record. Earth-Science Reviews 179, 95-122.Poggenburg, C., Mikutta, R., Schippers, A., Dohrmann, R., Guggenberger, G., 2018. Impact of natural organic matter coatings on the microbial reduction of iron oxides. Geochimica et Cosmochimica Acta 224, 223-248.Qiu, X., Yao, Y., Wang, H., Duan, Y., 2018. Live microbial cells adsorb Mg2+ more effectively than lifeless organic matter. Frontiers of Earth Science 12, 160-169.Reygondeau, G., Guieu, C., Benedetti, F., Irisson, J.-O., Ayata, S.-D., Gasparini, S., Koubbi, P., 2017. Biogeochemical regions of the Mediterranean Sea: An objective multidimensional and multivariate environmental approach. Progress in Oceanography 151, 138-148.Shelford, E.J., Suttle, C.A., 2018. Virus-mediated transfer of nitrogen from heterotrophic bacteria to phytoplankton. Biogeosciences 15, 809-819.Stegen, J.C., Johnson, T., Fredrickson, J.K., Wilkins, M.J., Konopka, A.E., Nelson, W.C., Arntzen, E.V., Chrisler, W.B., Chu, R.K., Fansler, S.J., Graham, E.B., Kennedy, D.W., Resch, C.T., Tfaily, M., Zachara, J., 2018. Influences of organic carbon speciation on hyporheic corridor biogeochemistry and microbial ecology. Nature Communications 9, Article 585.Sutton, J.N., André, L., Cardinal, D., Conley, D.J., de Souza, G.F., Dean, J., Dodd, J., Ehlert, C., Ellwood, M.J., Frings, P.J., Grasse, P., Hendry, K., Leng, M.J., Michalopoulos, P., Panizzo, V.N., Swann, G.E.A., 2018. A review of the stable isotope bio-geochemistry of the global silicon cycle and its associated trace elements. Frontiers in Earth Science 5, 112. doi: 110.3389/feart.2017.00112.Tapia-Torres, Y., Olmedo-?lvarez, G., 2018. Life on phosphite: A metagenomics tale. Trends in Microbiology 26, 170-172.Wang, L., Ye, L., Yu, Y., Jing, C., 2018. Antimony redox biotransformation in the subsurface: Effect of indigenous Sb(V) respiring microbiota. Environmental Science & Technology 52, 1200-1207.Biofilm/Microcial Induced CorrosionCarrel, M., Morales, V.L., Beltran, M.A., Derlon, N., Kaufmann, R., Morgenroth, E., Holzner, M., 2018. Biofilms in 3D porous media: Delineating the influence of the pore network geometry, flow and mass transfer on biofilm development. Water Research 134, 280-291.Escudero, C., Vera, M., Oggerin, M., Amils, R., 2018. Active microbial biofilms in deep poor porous continental subsurface rocks. Scientific Reports 8, Article 1538.Gaudreau, A.M., Labrie, J., Goetz, C., Dufour, S., Jacques, M., 2018. Evaluation of MALDI-TOF mass spectrometry for the identification of bacteria growing as biofilms. Journal of Microbiological Methods 145, 79-81.Lagree, K., Desai, J.V., Finkel, J.S., Lanni, F., 2018. Microscopy of fungal biofilms. Current Opinion in Microbiology 43, 100-107.Microbial Mediation of Mineral Formation/DegradationDhami, N.K., Mukherjee, A., Watkin, E.L.J., 2018. Microbial diversity and mineralogical-mechanical properties of calcitic cave speleothems in natural and in vitro biomineralization conditions. Frontiers in Microbiology 9, 40. doi: 10.3389/fmicb.2018.00040.Eskelsen, J.R., Xu, J., Chiu, M., Moon, J.-W., Wilkins, B., Graham, D.E., Gu, B., Pierce, E.M., 2018. Influence of structural defects on biomineralized ZnS nanoparticle dissolution: An in-situ electron microscopy study. Environmental Science & Technology 52, 1139-1149.Sundaram, S., Thakur, I.S., 2018. Induction of calcite precipitation through heightened production of extracellular carbonic anhydrase by CO2 sequestering bacteria. Bioresource Technology 253, 368-371.Carbon CycleBorges, A.V., Abril, G., Bouillon, S., 2018. Carbon dynamics and CO2 and CH4 outgassing in the Mekong delta. Biogeosciences 15, 1093-1114.Kondrik, D.V., Pozdnyakov, D.V., Johannessen, O.M., 2018. Satellite evidence that E. huxleyi phytoplankton blooms weaken marine carbon sinks. Geophysical Research Letters 45, 846-854.Laruelle, G.G., Cai, W.-J., Hu, X., Gruber, N., Mackenzie, F.T., Regnier, P., 2018. Continental shelves as a variable but increasing global sink for atmospheric carbon dioxide. Nature Communications 9, Article 454.Monroe, J.G., Markman, D.W., Beck, W.S., Felton, A.J., Vahsen, M.L., Pressler, Y., 2018. Ecoevolutionary dynamics of carbon cycling in the Anthropocene. Trends in Ecology & Evolution 33, 213-225.Müller, R.D., Dutkiewicz, A., 2018. Oceanic crustal carbon cycle drives 26-million-year atmospheric carbon dioxide periodicities. Science Advances 4, Article eaaq0500.Sea, M.A., Garcias-Bonet, N., Saderne, V., Duarte, C.M., 2018. Carbon dioxide and methane emissions from Red Sea mangrove sediments. Biogeosciences Discussions 2018, 1-38.Shen, Y., Benner, R., 2018. Mixing it up in the ocean carbon cycle and the removal of refractory dissolved organic carbon. Scientific Reports 8, Article 2542.Wang, C., Houlton, B.Z., Liu, D., Hou, J., Cheng, W., Bai, E., 2018. Stable isotopic constraints on global soil organic carbon turnover. Biogeosciences 15, 987-995.Yang, G., Peng, Y., Olefeldt, D., Chen, Y., Wang, G., Li, F., Zhang, D., Wang, J., Yu, J., Liu, L., Qin, S., Sun, T., Yang, Y., 2018. Changes in methane flux along a permafrost thaw sequence on the Tibetan Plateau. Environmental Science & Technology 52, 1244-1252.Carbon SequestrationAhmadi, P., Chapoy, A., 2018. CO2 solubility in formation water under sequestration conditions. Fluid Phase Equilibria 463, 80-90.Callow, B., Falcon-Suarez, I., Ahmed, S., Matter, J., 2018. Assessing the carbon sequestration potential of basalt using X-ray micro-CT and rock mechanics. International Journal of Greenhouse Gas Control 70, 146-156.Gheibi, S., Vilarrasa, V., Holt, R.M., 2018. Numerical analysis of mixed-mode rupture propagation of faults in reservoir-caprock system in CO2 storage. International Journal of Greenhouse Gas Control 71, 46-61.Huber, E.J., Stroock, A.D., Koch, D.L., 2018. Modeling the dynamics of remobilized CO2 within the geologic subsurface. International Journal of Greenhouse Gas Control 70, 128-145.Liang, B., Clarens, A.F., 2018. Interactions between stratigraphy and interfacial properties on flow and trapping in geologic carbon storage. Water Resources Research 54, 72-87.Newell, D.L., Carey, J.W., Backhaus, S.N., Lichtner, P., 2018. Experimental study of gravitational mixing of supercritical CO2. International Journal of Greenhouse Gas Control 71, 62-73.Pan, Y., Hui, D., Luo, P., Zhang, Y., Sun, L., Wang, K., 2018. Experimental investigation of the geochemical interactions between supercritical CO2 and shale: Implications for CO2 storage in gas-bearing shale formations. Energy & Fuels 32, 1963-1978.Piao, J., Han, W.S., Choung, S., Kim, K.-Y., 2018. Dynamic behavior of CO2 in a wellbore and storage formation: Wellbore-coupled and salt-precipitation processes during geologic CO2 sequestration. Geofluids 2018, Article 1789278,.Sorai, M., Sasaki, M., Kuribayashi, T., 2018. Field reaction experiments of carbonate minerals in spring waters: Natural analogue of geologic CO2 storage. Geofluids 2018, Article 2141878.Stork, A.L., Allmark, C., Curtis, A., Kendall, J.M., White, D.J., 2018. Assessing the potential to use repeated ambient noise seismic tomography to detect CO2 leaks: Application to the Aquistore storage site. International Journal of Greenhouse Gas Control 71, 20-35.White, D.J., 2018. 3D architecture of the Aquistore reservoir: Implications for CO2 flow and storage capacity. International Journal of Greenhouse Gas Control 71, 74-85.Climate ChangeBogard, M.J., Butman, D.E., 2018. No blast from the past. Nature Climate Change 8, 99-100.Carey, C.C., McClure, R.P., Doubek, J.P., Lofton, M.E., Ward, N.K., Scott, D.T., 2018. Chaoborus spp. transport CH4 from the sediments to the surface waters of a eutrophic reservoir, but their contribution to water column CH4 concentrations and diffusive efflux is minor. Environmental Science & Technology 52, 1165-1173.Elder, C.D., Xu, X., Walker, J., Schnell, J.L., Hinkel, K.M., Townsend-Small, A., Arp, C.D., Pohlman, J.W., Gaglioti, B.V., Czimczik, C.I., 2018. Greenhouse gas emissions from diverse Arctic Alaskan lakes are dominated by young carbon. Nature Climate Change 8, 166-171.Goodwin, P., Katavouta, A., Roussenov, V.M., Foster, G.L., Rohling, E.J., Williams, R.G., 2018. Pathways to 1.5 °C and 2 °C warming based on observational and geological constraints. Nature Geoscience 11, 102-107.Lüning, S., Ga?ka, M., Danladi, I.B., Adagunodo, T.A., Vahrenholt, F., 2018. Hydroclimate in Africa during the Medieval Climate Anomaly. Palaeogeography, Palaeoclimatology, Palaeoecology 495, 309-322.Shaffer, G., Lambert, F., 2018. In and out of glacial extremes by way of dust?climate feedbacks. Proceedings of the National Academy of Sciences 115, 2026-2031.Yue, R.P.H., Lee, H.F., 2018. Climate change and plague history in Europe. Science China Earth Sciences 61, 163-177.Coal/Lignite/Peat GeochemistryChen, X., Zhao, Y., Liu, L., Zhang, L., Zhang, Z., Qiu, P., 2018. Evaluation of chemical structure, pyrolysis reactivity and gaseous products of Shenmu coal of different particle sizes. Journal of Analytical and Applied Pyrolysis 130, 294-304.Du, Y., Sang, S., Wang, W., Liu, S., Wang, T., Fang, H., 2018. Experimental study of the reactions of supercritical CO2 and minerals in high-rank coal under formation conditions. Energy & Fuels 32, 1115-1125.Edress, N.A.A., Oplu?til, S., S?korová, I., 2018. Depositional environments of the Jurassic Maghara main coal seam in north central Sinai, Egypt. Journal of African Earth Sciences 140, 241-255.Gan, H., Wang, H., Chen, J., Zhuang, X., Cao, H., Jiang, S., 2018. Geochemical characteristics of Jurassic coal and its paleoenvironmental implication in the eastern Junggar Basin, China. Journal of Geochemical Exploration 188, 73-86.Goswami, V., Hannah, J.L., Stein, H.J., 2018. Why terrestrial coals cannot be dated using the Re-Os geochronometer: Evidence from the Finnmark Platform, southern Barents Sea and the Fire Clay coal horizon, Central Appalachian Basin. International Journal of Coal Geology 188, 121-135.Inglis, G.N., Naafs, B.D.A., Zheng, Y., McClymont, E.L., Evershed, R.P., Pancost, R.D., 2018. Distributions of geohopanoids in peat: Implications for the use of hopanoid-based proxies in natural archives. Geochimica et Cosmochimica Acta 224, 249-261.Jia, F., Lu, R., Liu, X., Zhao, C., Lv, Z., Gao, S., 2018. Palaeoenvironmental implications of a Holocene sequence of lacustrine-peat sediments from the desert-loess transitional zone in Northern China. Journal of Asian Earth Sciences 156, 167-173.Kara-Gülbay, R., Korkmaz, S., Yaylal?-Abanuz, G., Erdo?an, M.S., 2018. Organic geochemistry and depositional environment of the Oltu Gemstone (coal) in the Erzurum Area, NE Anatolia, Turkey. Energy & Fuels 32, 1451-1463.Li, W., Zhu, Y.-M., Liu, Y., 2018. Gas evolution and isotopic fractionations during pyrolysis on coals of different ranks. International Journal of Coal Geology 188, 136-144.Moroeng, O.M., Wagner, N.J., Brand, D.J., Roberts, R.J., 2018. A Nuclear Magnetic Resonance study: Implications for coal formation in the Witbank Coalfield, South Africa. International Journal of Coal Geology 188, 145-155.Qin, S., Lu, Q., Li, Y., Wang, J., Zhao, Q., Gao, K., 2018. Relationships between trace elements and organic matter in coals. Journal of Geochemical Exploration 188, 101-110.Radlinski, A.P., Mastalerz, M., 2018. Neutron scattering study of vitrinite: Insights into sub-micrometer inclusions in North American Carboniferous coals of bituminous rank. International Journal of Coal Geology 186, 145-154.Sakurovs, R., Koval, L., Grigore, M., Sokolova, A., Ruppert, L.F., Melnichenko, Y.B., 2018. Nanometre-sized pores in coal: Variations between coal basins and coal origin. International Journal of Coal Geology 186, 126-134.Xu, J., Tang, H., Su, S., Liu, J., Xu, K., Qian, K., Wang, Y., Zhou, Y., Hu, S., Zhang, A., Xiang, J., 2018. A study of the relationships between coal structures and combustion characteristics: The insights from micro-Raman spectroscopy based on 32 kinds of Chinese coals. Applied Energy 212, 46-56.Zhou, H.W., Zhong, J.C., Ren, W.G., Wang, X.Y., Yi, H.Y., 2018. Characterization of pore-fracture networks and their evolution at various measurement scales in coal samples using X-ray μCT and a fractal method. International Journal of Coal Geology 189, 35-49.Coal Bed MethaneFuertez, J., Córdoba, G., McLennan, J.D., Adams, D.J., Sparks, T.D., 2018. Potential application of developed methanogenic microbial consortia for coal biogasification. International Journal of Coal Geology 188, 165-180.Liu, H., Sang, S., Xue, J., Lan, T., Xu, H., Ren, B., Liu, S., 2018. Evolution and geochemical characteristics of gas phase fluid and its response to inter-well interference during multi-well drainage of coalbed methane. Journal of Petroleum Science and Engineering 162, 491-501.Niu, Q., Cao, L., Sang, S., Zhou, X., Wang, Z., 2018. Anisotropic adsorption swelling and permeability characteristics with injecting CO2 in coal. Energy & Fuels 32, 1979-1991.Zeng, Q., Wang, Z., Liu, L., Ye, J., McPherson, B.J., McLennan, J.D., 2018. Modeling CH4 displacement by CO2 in deformed coalbeds during enhanced coalbed methane recovery. Energy & Fuels 32, 1942-1955.Zhao, J., Tang, D., Qin, Y., Xu, H., Liu, Y., Wu, H., 2018. Characteristics of methane (CH4) diffusion in coal and its influencing factors in the Qinshui and Ordos basins. Energy & Fuels 32, 1196-1205.Cosmochemistry/Planetary GeochemistryApplin, D.M., Izawa, M.R.M., Cloutis, E.A., Gillis-Davis, J.J., Pitman, K.M., Roush, T.L., Hendrix, A.R., Lucey, P.G., 2018. Ultraviolet spectral reflectance of carbonaceous materials. Icarus 307, 40-82.Avice, G., Bekaert, D.V., Chennaoui Aoudjehane, H., Marty, B., 2018. Noble gases and nitrogen in Tissint reveal the composition of the Mars atmosphere. Geochemical Perspectives Letters 6, 11-16.Battandier, M., Bonal, L., Quirico, E., Beck, P., Engrand, C., Duprat, J., Dartois, E., 2018. Characterization of the organic matter and hydration state of Antarctic micrometeorites: A reservoir distinct from carbonaceous chondrites. Icarus 306, 74-93.Cloutis, E.A., Pietrasz, V.B., Kiddell, C., Izawa, M.R.M., Vernazza, P., Burbine, T.H., DeMeo, F., Tait, K.T., Bell III, J.F., Mann, P., Applin, D.M., Reddy, V., 2018. Spectral reflectance “deconstruction” of the Murchison CM2 carbonaceous chondrite and implications for spectroscopic investigations of dark asteroids. Icarus 305, 203-224.Dai, X., Eduardo, G., 2018. Probing planets in extragalactic galaxies using quasar microlensing. The Astrophysical Journal Letters 853, Article L27.Eshelman, E., Daly, M.G., Slater, G., Cloutis, E., 2017. Detecting aromatic compounds on planetary surfaces using ultraviolet time-resolved fluorescence spectroscopy. Planetary and Space Science 151, 1-10.Hong, P., Sekine, Y., Sasamori, T., Sugita, S., 2018. Experimental study of heterogeneous organic chemistry induced by far ultraviolet light: Implications for growth of organic aerosols by CH3 addition in the atmospheres of Titan and early Earth. Icarus 307, 25-39.Melin, H., Fletcher, L.N., Donnelly, P.T., Greathouse, T.K., Lacy, J.H., Orton, G.S., Giles, R.S., Sinclair, J.A., Irwin, P.G.J., 2018. Assessing the long-term variability of acetylene and ethane in the stratosphere of Jupiter. Icarus 305, 301-313.Moros, J., ElFaham, M.M., Laserna, J.J., 2018. Dual-spectroscopy platform for the surveillance of Mars mineralogy using a decisions fusion architecture on simultaneous LIBS-Raman data. Analytical Chemistry 90, 2079-2087.Mu?oz-Iglesias, V., Choukroun, M., Vu, T.H., Hodyss, R., Mahjoub, A., Smythe, W.D., Sotin, C., 2018. Phase diagram of the ternary water–tetrahydrofuran–ammonia system at low temperatures. Implications for clathrate hydrates and outgassing on Titan. ACS Earth and Space Chemistry 2, 135-146.Ray, D., Shukla, A.D., 2018. The Mukundpura meteorite, a new fall of CM chondrite. Planetary and Space Science 151, 149-154.Sato, A., Kitazawa, Y., Ochi, T., Shoji, M., Komatsu, Y., Kayanuma, M., Aikawa, Y., Umemura, M., Shigeta, Y., 2018. First-principles study of the formation of glycine-producing radicals from common interstellar species. Molecular Astrophysics 10, 11-19.Vinogradoff, V., Bernard, S., Le Guillou, C., Remusat, L., 2018. Evolution of interstellar organic compounds under asteroidal hydrothermal conditions. Icarus 305, 358-370.AstrobiologyAltair, T., de Avellar, M.G.B., Rodrigues, F., Galante, D., 2018. Microbial habitability of Europa sustained by radioactive sources. Scientific Reports 8, Article 260.Berliner, A.J., Mochizuki, T., Stedman, K.M., 2018. Astrovirology: Viruses at large in the universe. Astrobiology 18, 207-223.Cockell, C.S., Biller, B., Bryce, C., Cousins, C., Direito, S., Forgan, D., Fox-Powell, M., Harrison, J., Landenmark, H., Nixon, S., Payler, S.J., Rice, K., Samuels, T., Schwendner, P., Stevens, A., Nicholson, N., Wadsworth, J., 2018. The UK Centre for Astrobiology: A virtual astrobiology centre. Accomplishments and lessons learned, 2011–2016. Astrobiology 18, 224-243.Fairén, A.G., Parro, V., Schulze-Makuch, D., Whyte, L., 2018. Is searching for martian life a priority for the Mars community? Astrobiology 18, 101-107.Keles, E., Grenfell, J.L., Godolt, M., Stracke, B., Rauer, H., 2018. The effect of varying atmospheric pressure upon habitability and biosignatures of Earth-like planets. Astrobiology 18, 116-132.Maynard, A.D., 2018. Thinking differently about risk. Astrobiology 18, 244-245.Meadows, V.S., Arney, G.N., Schwieterman, E.W., Lustig-Yaeger, J., Lincowski, A.P., Robinson, T., Domagal-Goldman, S.D., Deitrick, R., Barnes, R.K., Fleming, D.P., Luger, R., Driscoll, P.E., Quinn, T.R., Crisp, D., 2018. The habitability of Proxima Centauri b: Environmental states and observational discriminants. Astrobiology 18, 133-189.Rummel, J.D., Conley, C.A., 2018. Inadvertently finding earth contamination on Mars should not be a priority for anyone. Astrobiology 18, 108-115.Spirina, E.V., Durdenko, E.V., Demidov, N.E., Abramov, A.A., Romanovsky, V.E., Rivkina, E.M., 2017. Halophilic-psychrotrophic bacteria of an Alaskan cryopeg—a model for astrobiology. Paleontological Journal 51, 1440-1452.Taubner, R.-S., Pappenreiter, P., Zwicker, J., Smrzka, D., Pruckner, C., Kolar, P., Bernacchi, S., Seifert, A.H., Krajete, A., Bach, W., Peckmann, J., Paulik, C., Firneis, M.G., Schleper, C., Rittmann, S.K.M.R., 2018. Biological methane production under putative Enceladus-like conditions. Nature Communications 9, Article 748.Taylor, E.R., 2018. If technological intelligent extraterrestrials exist, what biological traits are de rigueur. Life Sciences in Space Research 17, 15-22.Vance, S.D., Panning, M.P., St?hler, S., Cammarano, F., Bills, B.G., Tobie, G., Kamata, S., Kedar, S., Sotin, C., Pike, W.T., Lorenz, R., Huang, H.-H., Jackson, J.M., Banerdt, B., 2018. Geophysical investigations of habitability in ice-covered ocean worlds. Journal of Geophysical Research: Planets 123, 180-205.Wierzchos, J., Casero, M.C., Artieda, O., Ascaso, C., 2018. Endolithic microbial habitats as refuges for life in polyextreme environment of the Atacama Desert. Current Opinion in Microbiology 43, 124-131.Environmental GeochemistryAderhold, D.G.R., Lindeberg, M.R., Holderied, K., Pegau, S.W., 2018. Spatial and temporal ecological variability in the northern Gulf of Alaska: What have we learned since the Exxon Valdez oil spill? Deep Sea Research Part II: Topical Studies in Oceanography 147, 3-8.Arsic, M., Teasdale, P.R., Welsh, D.T., Johnston, S.G., Burton, E.D., Hockmann, K., Bennett, W.W., 2018. Diffusive gradients in thin films reveals differences in antimony and arsenic mobility in a contaminated wetland sediment during an oxic-anoxic transition. Environmental Science & Technology 52, 1118-1127.Bandowe, B.A.M., Bigalke, M., Kobza, J., Wilcke, W., 2018. Sources and fate of polycyclic aromatic compounds (PAHs, oxygenated PAHs and azaarenes) in forest soil profiles opposite of an aluminium plant. Science of The Total Environment 630, 83-95.Bowen, L., Miles, A.K., Ballachey, B., Waters, S., Bodkin, J., Lindeberg, M., Esler, D., 2018. Gene transcription patterns in response to low level petroleum contaminants in Mytilus trossulus from field sites and harbors in southcentral Alaska. Deep Sea Research Part II: Topical Studies in Oceanography 147, 27-35.Br?nner, U., Johansen, ?., Leirvik, F., Nordam, T., S?rheim, K.R., 2018. Spreading of waxy oils on calm water. Marine Pollution Bulletin 129, 135-141.de Oliveira Livera, D., Leshuk, T., Peru, K.M., Headley, J.V., Gu, F., 2018. Structure-reactivity relationship of naphthenic acids in the photocatalytic degradation process. Chemosphere 200, 180-190.Grieve, P.L., Hynek, S.A., Heilweil, V., Sowers, T., Llewellyn, G., Yoxtheimer, D., Solomon, D.K., Brantley, S.L., 2018. Using environmental tracers and modelling to identify natural and gas well-induced emissions of methane into streams. Applied Geochemistry 91, 107-121.Han, Y., Nambi, I.M., Prabhakar Clement, T., 2018. Environmental impacts of the Chennai oil spill accident – A case study. Science of The Total Environment 626, 795-806.Hendrickson, E., Minor, E.C., Schreiner, K., 2018. Microplastic abundance and composition in western Lake Superior as determined via microscopy, Pyr-GC/MS, and FTIR. Environmental Science & Technology 52, 1787-1796.Lindeberg, M.R., Maselko, J., Heintz, R.A., Fugate, C.J., Holland, L., 2018. Conditions of persistent oil on beaches in Prince William Sound 26 years after the Exxon Valdez spill. Deep Sea Research Part II: Topical Studies in Oceanography 147, 9-19.Molinier, V., Le Goué, E., Rondón-Gonzáles, M., Passade-Boupat, N., Bourrel, M., 2018. Optimization of chemical dispersants effectiveness in case of subsurface oil spill. Colloids and Surfaces A: Physicochemical and Engineering Aspects 541, 43-51.Nakamura, M., Ikeda, Y., Matsumoto, A., Maki, H., Arakawa, H., 2018. Distribution of hydrocarbons in seabed sediments derived from tsunami-spilled oil in Kesennuma Bay, Japan. Marine Pollution Bulletin 128, 115-125.Nixon, Z., Michel, J., 2017. A review of distribution and quantity of lingering subsurface oil from the Exxon Valdez oil spill. Deep Sea Research Part II: Topical Studies in Oceanography 147, 20-26.Raposo, D., Clemente, I., Figueiredo, M., Vilar, A., Lorini, M.L., Frontalini, F., Martins, V., Belart, P., Fontana, L., Habib, R., Laut, L., 2018. Benthic foraminiferal and organic matter compounds as proxies of environmental quality in a tropical coastal lagoon: The Itaipu lagoon (Brazil). Marine Pollution Bulletin 129, 114-125.Ravikumar, A.P., Wang, J., McGuire, M., Bell, C.S., Zimmerle, D., Brandt, A.R., 2018. “Good versus good enough?” Empirical tests of methane leak detection sensitivity of a commercial infrared camera. Environmental Science & Technology 52, 2368-2374.Scheibye, K., Christensen, J.H., Johnsen, A.R., 2017. Biodegradation of crude oil in Arctic subsurface water from the Disko Bay (Greenland) is limited. Environmental Pollution 223, 73-80.Shen, X., Chang, H., Sun, D., Wang, L., Wu, F., 2018. Trace analysis of 61 natural and synthetic progestins in river water and sewage effluents by ultra-high performance liquid chromatography–tandem mass spectrometry. Water Research 133, 142-152.Srivastava, D., Tomaz, S., Favez, O., Lanzafame, G.M., Golly, B., Besombes, J.-L., Alleman, L.Y., Jaffrezo, J.-L., Jacob, V., Perraudin, E., Villenave, E., Albinet, A., 2018. Speciation of organic fraction does matter for source apportionment. Part 1: A one-year campaign in Grenoble (France). Science of The Total Environment 624, 1598-1611.Tarrant, A.M., Payton, S.L., Reitzel, A.M., Porter, D.T., Jenny, M.J., 2018. Ultraviolet radiation significantly enhances the molecular response to dispersant and sweet crude oil exposure in Nematostella vectensis. Marine Environmental Research 134, 96-108.Vergeynst, L., Wegeberg, S., Aamand, J., Lassen, P., Gosewinkel, U., Fritt-Rasmussen, J., Gustavson, K., Mosbech, A., 2018. Biodegradation of marine oil spills in the Arctic with a Greenland perspective. Science of The Total Environment 626, 1243-1258.Wang, Y., Liang, J., Wang, J., Gao, S., 2018. Combining stable carbon isotope analysis and petroleum-fingerprinting to evaluate petroleum contamination in the Yanchang oilfield located on loess plateau in China. Environmental Science and Pollution Research 25, 2830-2841.Webster, L., Russell, M., Shepherd, N., Packer, G., Dalgarno, E.J., Neat, F., 2018. Monitoring of polycyclic aromatic hydrocarbons (PAHs) in Scottish deepwater environments. Marine Pollution Bulletin 128, 456-459.Yang, J., Li, G., Qian, Y., Yang, Y., Zhang, F., 2018. Microbial functional gene patterns related to soil greenhouse gas emissions in oil contaminated areas. Science of The Total Environment 628–629, 94-102.Zhang, H., Yang, M., 2018. Characterization of brominated disinfection byproducts formed during chloramination of fulvic acid in the presence of bromide. Science of The Total Environment 627, 118-124.BioremediationBaltrons, O., López-Mesas, M., Vilaseca, M., Gutiérrez-Bouzán, C., Le Derf, F., Portet-Koltalo, F., Palet, C., 2018. Influence of a mixture of metals on PAHs biodegradation processes in soils. Science of The Total Environment 628–629, 150-158.García-Cruz, N.U., Sánchez-Avila, J.I., Valdés-Lozano, D., Gold-Bouchot, G., Aguirre-Macedo, L., 2018. Biodegradation of hexadecane using sediments from rivers and lagoons of the Southern Gulf of Mexico. Marine Pollution Bulletin 128, 202-207.Hong, J.-K., Jho, E.H., Choi, H.S., Kang, G., 2018. Role of hemoglobin in hemoglobin-based remediation of the crude oil-contaminated soil. Science of The Total Environment 627, 1174-1181.Hussain, I., Aleti, G., Naidu, R., Puschenreiter, M., Mahmood, Q., Rahman, M.M., Wang, F., Shaheen, S., Syed, J.H., 2018. Microbe and plant assisted-remediation of organic xenobiotics and its enhancement by genetically modified organisms and recombinant technology: A review. Science of The Total Environment 628–629, 1582–1599.Kong, F.-x., Sun, G.-d., Liu, Z.-p., 2018. Degradation of polycyclic aromatic hydrocarbons in soil mesocosms by microbial/plant bioaugmentation: Performance and mechanism. Chemosphere 198, 83-91.Nowak, J.A., Shrestha, P.M., Weber, R.J., McKenna, A.M., Chen, H., Coates, J.D., Goldstein, A.H., 2018. Comprehensive analysis of changes in crude oil chemical composition during biosouring and treatments. Environmental Science & Technology 52, 1290-1300.Okoro, C.C., Nwezza, E.E., Lin, J., 2018. Persistence of halophylic methanogens and oil-degrading bacteria in an offshore oil-producing facility. Geomicrobiology Journal 35, 323-333.Sivaram, A.K., Logeshwaran, P., Subashchandrabose, S.R., Lockington, R., Naidu, R., Megharaj, M., 2018. Comparison of plants with C3 and C4 carbon fixation pathways for remediation of polycyclic aromatic hydrocarbon contaminated soils. Scientific Reports 8, Article 2100.Zhao, G., Sheng, Y., Wang, C., Yang, J., Wang, Q., Chen, L., 2018. In situ microbial remediation of crude oil-soaked marine sediments using zeolite carrier with a polymer coating. Marine Pollution Bulletin 129, 172-178.Zheng, J., Feng, J.-Q., Zhou, L., Mbadinga, S.M., Gu, J.-D., Mu, B.-Z., 2018. Characterization of bacterial composition and diversity in a long-term petroleum contaminated soil and isolation of high-efficiency alkane-degrading strains using an improved medium. World Journal of Microbiology and Biotechnology 34, 34.Deepwater Horizon/MacondoAlexander, M., Engel, L.S., Olaiya, N., Wang, L., Barrett, J., Weems, L., Schwartz, E.G., Rusiecki, J.A., 2018. The Deepwater Horizon oil spill Coast Guard cohort study: A cross-sectional study of acute respiratory health symptoms. Environmental Research 162, 196-202.Ward, C.P., Sharpless, C.M., Valentine, D.L., French-McCay, D.P., Aeppli, C., White, H.K., Rodgers, R.P., Gosselin, K.M., Nelson, R.K., Reddy, C.M., 2018. Partial photochemical oxidation was a dominant fate of Deepwater Horizon surface oil. Environmental Science & Technology 52, 1797-1805.Oil Sand Process Waters/Tailing PondsOrellana, A., Laurenzi, I.J., MacLean, H.L., Bergerson, J.A., 2017. Statistically enhanced model of in situ oil sands extraction operations: An evaluation of variability in greenhouse gas emissions. Environmental Science & Technology 52, 947-954.Stefani, F., Isabel, N., Morency, M.-J., Lamothe, M., Nadeau, S., Lachance, D., Li, E.H.Y., Greer, C., Yergeau, ?., Pinno, B.D., Séguin, A., 2018. The impact of reconstructed soils following oil sands exploitation on aspen and its associated belowground microbiome. Scientific Reports 8, Article 2761.Xue, J., Huang, C., Zhang, Y., Liu, Y., Gamal El-Din, M., 2018. Bioreactors for oil sands process-affected water (OSPW) treatment: A critical review. Science of The Total Environment 627, 916-933.Zhang, L., Zhang, Y., Gamal El-Din, M., 2018. Degradation of recalcitrant naphthenic acids from raw and ozonated oil sands process-affected waters by a semi-passive biofiltration process. Water Research 133, 310-318.UnconventionalShale Gas-CBM ResourcesBain, P.A., Kumar, A., 2018. In?vitro nuclear receptor inhibition and cytotoxicity of hydraulic fracturing chemicals and their binary mixtures. Chemosphere 198, 565-573.Koz?owska, M., Brudzinski, M.R., Friberg, P., Skoumal, R.J., Baxter, N.D., Currie, B.S., 2018. Maturity of nearby faults influences seismic hazard from hydraulic fracturing. Proceedings of the National Academy of Sciences 115, E1720.Lauer, N.E., Warner, N.R., Vengosh, A., 2018. Sources of radium accumulation in stream sediments near disposal sites in Pennsylvania: Implications for disposal of conventional oil and gas wastewater. Environmental Science & Technology 52, 955-962.Saunders, P.J., McCoy, D., Goldstein, R., Saunders, A.T., Munroe, A., 2018. A review of the public health impacts of unconventional natural gas development. Environmental Geochemistry and Health 40, 1-57.Torres, L., Yadav, O.P., Khan, E., 2018. Risk assessment of human exposure to Ra-226 in oil produced water from the Bakken Shale. Science of The Total Environment 626, 867-874.Evolution/Paleontology/PalynologyAstudillo-García, C., Slaby, B.M., Waite, D.W., Bayer, K., Hentschel, U., Taylor, M.W., 2018. Phylogeny and genomics of SAUL, an enigmatic bacterial lineage frequently associated with marine sponges. Environmental Microbiology 20, 561-576.Boast, A.P., Weyrich, L.S., Wood, J.R., Metcalf, J.L., Knight, R., Cooper, A., 2018. Coprolites reveal ecological interactions lost with the extinction of New Zealand birds. Proceedings of the National Academy of Sciences 115, 1546.Botting, J.P., Muir, L.A., 2018. Early sponge evolution: A review and phylogenetic framework. Palaeoworld 27, 1-29.Donoghue, P., 2018. Evolution: Divining the nature of the ancestral vertebrate. Current Biology 27, R277-R279.Graf, J., Tabor, N.J., Ferguson, K., Winkler, D.A., Lee, Y.-N., May, S., Jacobs, L.L., 2018. Diagenesis of dinosaur eggshell from the Gobi Desert, Mongolia. Palaeogeography, Palaeoclimatology, Palaeoecology 494, 65-74.Jung, H., Baek, M., D’Elia, K.P., Boisvert, C., Currie, P.D., Tay, B.-H., Venkatesh, B., Brown, S.M., Heguy, A., Schoppik, D., 2018. The ancient origins of neural substrates for land walking. Cell 172, 667-682.Landing, E., Antcliffe, J.B., Geyer, G., Kouchinsky, A., Bowser, S.S., Andreas, A., 2018. Early evolution of colonial animals (Ediacaran Evolutionary Radiation–Cambrian Evolutionary Radiation–Great Ordovician Biodiversification Interval). Earth-Science Reviews 178, 105-135.Lu, L.-M., Mao, L.-F., Yang, T., Ye, J.-F., Liu, B., Li, H.-L., Sun, M., Miller, J.T., Mathews, S., Hu, H.-H., Niu, Y.-T., Peng, D.-X., Chen, Y.-H., Smith, S.A., Chen, M., Xiang, K.-L., Le, C.-T., Dang, V.-C., Lu, A.-M., Soltis, P.S., Soltis, D.E., Li, J.-H., Chen, Z.-D., 2018. Evolutionary history of the angiosperm flora of China. Nature 554, 234-238.Mehra, A., Maloof, A., 2018. Multiscale approach reveals that Cloudina aggregates are detritus and not in situ reef constructions. Proceedings of the National Academy of Sciences.Morga, R., Pawlyta, M., 2018. Microstructure of graptolite periderm in Silurian gas shales of Northern Poland. International Journal of Coal Geology 189, 1-7.O’Donovan, C., Meade, A., Venditti, C., 2018. Dinosaurs reveal the geographical signature of an evolutionary radiation. Nature Ecology & Evolution 2, 452-458.Pérez-Huerta, A., Coronado, I., Hegna, T.A., 2018. Understanding biomineralization in the fossil record. Earth-Science Reviews 179, 95-122.Tarhan, L.G., 2018. The early Paleozoic development of bioturbation—Evolutionary and geobiological consequences. Earth-Science Reviews 178, 177-207.Vrazo, M.B., Diefendorf, A.F., Crowley, B.E., Czaja, A.D., 2018. Late Cretaceous marine arthropods relied on terrestrial organic matter as a food source: Geochemical evidence from the Coon Creek Lagerst?tte in the Mississippi Embayment. Geobiology 16, 160-178.Yang, J., Ortega-Hernández, J., Legg, D.A., Lan, T., Hou, J.-b., Zhang, X.-g., 2018. Early Cambrian fuxianhuiids from China reveal origin of the gnathobasic protopodite in euarthropods. Nature Communications 9, Article 470.Zhang, L., Chang, S., Khan, M.Z., Feng, Q., Danelian, T., Clausen, S., Tribovillard, N., Steiner, M., 2018. The link between metazoan diversity and paleo-oxygenation in the early Cambrian: An integrated palaeontological and geochemical record from the eastern Three Gorges Region of South China. Palaeogeography, Palaeoclimatology, Palaeoecology 495, 24-41.Origins of Life/Microbial GenomicsAdam, P.S., Borrel, G., Gribaldo, S., 2018. Evolutionary history of carbon monoxide dehydrogenase/acetyl-CoA synthase, one of the oldest enzymatic complexes. Proceedings of the National Academy of Sciences 115, E1166-E1173.Aydinoglu, A.U., Ta?k?n, Z., 2018. Origins of life research: A bibliometric approach. Origins of Life and Evolution of Biospheres 48, 55-71.Cantine, M.D., Fournier, G.P., 2018. Environmental adaptation from the origin of life to the Last Universal Common Ancestor. Origins of Life and Evolution of Biospheres 48, 35-54.Dement’ev, V.A., 2018. Origin of the simplest genetic code as an evolutionary stage of the Earth. Geochemistry International 56, 65-70.Di Donato, P., Romano, I., Mastascusa, V., Poli, A., Orlando, P., Pugliese, M., Nicolaus, B., 2018. Survival and adaptation of the thermophilic species Geobacillus thermantarcticus in simulated spatial conditions. Origins of Life and Evolution of Biospheres 48, 141-158.Doan, T.N., Fujihara, A., 2018. Enantiomer-selective photo-induced reaction of protonated tryptophan with disaccharides in the gas phase. Origins of Life and Evolution of Biospheres 48, 123-130.Famiano, M.A., Boyd, R.N., Kajino, T., Onaka, T., 2018. Selection of amino acid chirality via neutrino interactions with 14N in crossed electric and magnetic fields. Astrobiology 18, 190-206.Fitzek, E., Joardar, A., Gupta, R., Geisler, M., 2018. Evolution of eukaryal and archaeal pseudouridine synthase Pus10. Journal of Molecular Evolution 86, 77-89.Froese, T., Campos, J.I., Fujishima, K., Kiga, D., Virgo, N., 2018. Horizontal transfer of code fragments between protocells can explain the origins of the genetic code without vertical descent. Scientific Reports 8, Article 3532.Furukawa, Y., Takase, A., Sekine, T., Kakegawa, T., Kobayashi, T., 2018. Racemization of valine by impact-induced heating. Origins of Life and Evolution of Biospheres 48, 131-139.Hirashima, T., Toyoshima, M., Moriyama, T., Sato, N., 2018. Evolution of the phosphatidylcholine biosynthesis pathways in green algae: Combinatorial diversity of methyltransferases. Journal of Molecular Evolution 86, 68-76.Inaba, S., 2018. Primary formation path of formaldehyde in hydrothermal vents. Origins of Life and Evolution of Biospheres 48, 1-22.Kelman, L.M., Kelman, Z., 2018. Do archaea need an origin of replication? Trends in Microbiology 26, 172-174.Kitadai, N., Nishiuchi, K., Nishii, A., Fukushi, K., 2018. Amorphous silica-promoted lysine dimerization: A thermodynamic prediction. Origins of Life and Evolution of Biospheres 48, 23-34.Konstantinov, K.K., Konstantinova, A.F., 2018. Chiral symmetry breaking in peptide systems during formation of life on Earth. Origins of Life and Evolution of Biospheres 48, 93-122.Magnabosco, C., Moore, K.R., Wolfe, J.M., Fournier, G.P., 2018. Dating phototrophic microbial lineages with reticulate gene histories. Geobiology 16, 179-189.Points, L.J., Taylor, J.W., Grizou, J., Donkers, K., Cronin, L., 2018. Artificial intelligence exploration of unstable protocells leads to predictable properties and discovery of collective behavior. Proceedings of the National Academy of Sciences 115, 885-890.Raanan, H., Pike, D.H., Moore, E.K., Falkowski, P.G., Nanda, V., 2018. Modular origins of biological electron transfer chains. Proceedings of the National Academy of Sciences 115, 1280-1285;.Ransohoff, J.D., Wei, Y., Khavari, P.A., 2017. The functions and unique features of long intergenic non-coding RNA. Nature Reviews Molecular Cell Biology 19, 143.Rivas, M., Becerra, A., Lazcano, A., 2018. On the early evolution of catabolic pathways: A comparative genomics approach. I. The cases of glucose, ribose, and the nucleobases catabolic routes. Journal of Molecular Evolution 86, 27-46.Tapia-Torres, Y., Olmedo-?lvarez, G., 2018. Life on phosphite: A metagenomics tale. Trends in Microbiology 26, 170-172.Ward, L., Hemp, J., Shih, P., McGlynn, S., Fischer, W., 2018. Evolution of phototrophy in the Chloroflexi phylum driven by horizontal gene transfer. Frontiers in Microbiology 9, 260. doi: 210.3389/fmicb.2018.00260 Zachar, I., Szilágyi, A., Számadó, S., Szathmáry, E., 2018. Farming the mitochondrial ancestor as a model of endosymbiotic establishment by natural selection. Proceedings of the National Academy of Sciences 115, E1504-E1510.Zamudio, G.S., José, M.V., 2018. Identity elements of tRNA as derived from information analysis. Origins of Life and Evolution of Biospheres 48, 73-81.Zamudio, G.S., José, M.V., 2018. Phenotypic graphs and evolution unfold the Standard Genetic Code as the optimal. Origins of Life and Evolution of Biospheres 48, 83-91.Hominid EvolutionAkhilesh, K., Pappu, S., Rajapara, H.M., Gunnell, Y., Shukla, A.D., Singhvi, A.K., 2018. Early Middle Palaeolithic culture in India around 385–172 ka reframes Out of Africa models. Nature 554, 97-101.Appenzeller, T., 2018. Europe's first artists were Neandertals. Science 359, 852-853.Aranguren, B., Revedin, A., Amico, N., Cavulli, F., Giachi, G., Grimaldi, S., Macchioni, N., Santaniello, F., 2018. Wooden tools and fire technology in the early Neanderthal site of Poggetti Vecchi (Italy). Proceedings of the National Academy of Sciences 115, 2054-2059.Callaway, E., 2018. Israeli fossils are the oldest modern humans ever found outside of Africa. Nature 554, 15-16.Hoffmann, D.L., Angelucci, D.E., Villaverde, V., Zapata, J., Zilh?o, J., 2018. Symbolic use of marine shells and mineral pigments by Iberian Neandertals 115,000 years ago. Science Advances 4, Article eaar5255.Hoffmann, D.L., Standish, C.D., García-Diez, M., Pettitt, P.B., Milton, J.A., Zilh?o, J., Alcolea-González, J.J., Cantalejo-Duarte, P., Collado, H., de Balbín, R., Lorblanchet, M., Ramos-Mu?oz, J., Weniger, G.C., Pike, A.W.G., 2018. U-Th dating of carbonate crusts reveals Neandertal origin of Iberian cave art. Science 359, 912-915.Meindl, R.S., Chaney, M.E., Lovejoy, C.O., 2018. Early hominids may have been weed species. Proceedings of the National Academy of Sciences 115, 1244-1249.Raghanti, M.A., Edler, M.K., Stephenson, A.R., Munger, E.L., Jacobs, B., Hof, P.R., Sherwood, C.C., Holloway, R.L., Lovejoy, C.O., 2018. A neurochemical hypothesis for the origin of hominids. Proceedings of the National Academy of Sciences 115, E1108-E1116 Fluid InclusionsChen, L., Meyer, J., Campbell, T., Canas, J., Betancourt, S.S., Dumont, H., Forsythe, J.C., Mehay, S., Kimball, S., Hall, D.L., Nighswander, J., Peters, K.E., Zuo, J.Y., Mullins, O.C., 2018. Applicability of simple asphaltene thermodynamics for asphaltene gradients in oilfield reservoirs: The Flory-Huggins-Zuo Equation of State with the Yen-Mullins model. Fuel 221, 216-232.Khalifa, M.A., Mansurbeg, H., Morad, D., Morad, S., Al-Aasm, I.S., Spirov, P., Ceriani, A., De Ros, L.F., 2018. Quartz and Fe-dolomite cements record shifts in formation-water chemistry and hydrocarbon migration in Devonian shoreface sandstones, Ghadamis Basin, Libya. Journal of Sedimentary Research 88, 38-57.Pagel, M., Bonifacie, M., Schneider, D.A., Gautheron, C., Brigaud, B., Calmels, D., Cros, A., Saint-Bezar, B., Landrein, P., Sutcliffe, C., Davis, D., Chaduteau, C., 2018. Improving paleohydrological and diagenetic reconstructions in calcite veins and breccia of a sedimentary basin by combining Δ47 temperature, δ18Owater and U-Pb age. Chemical Geology 481, 1-17.Peters, C.A., Hallmann, C., George, S.C., 2018. Phenolic compounds in oil-bearing fluid inclusions: Implications for water-washing and oil migration. Organic Geochemistry 118, 36-46.Rudmin, M., Roberts, A.P., Horng, C.-S., Mazurov, A., Savinova, O., Ruban, A., Kashapov, R., Veklich, M., 2018. Ferrimagnetic iron sulfide formation and methane venting across the Paleocene-Eocene Thermal Maximum in shallow marine sediments, ancient West Siberian Sea. Geochemistry, Geophysics, Geosystems 19, 21-42.Yang, C., Ni, Z., Li, M., Wang, T., Chen, Z., Hong, H., Tian, X., 2018. Pyrobitumen in South China: Organic petrology, chemical composition and geological significance. International Journal of Coal Geology 188, 51-63.General InterestMarcinkowski, M.D., Darby, M.T., Liu, J., Wimble, J.M., Lucci, F.R., Lee, S., Michaelides, A., Flytzani-Stephanopoulos, M., Stamatakis, M., Sykes, E.C.H., 2018. Pt/Cu single-atom alloys as coke-resistant catalysts for efficient C–H activation. Nature Chemistry 10, 325-332.GeologyCabestrero, ?., del Buey, P., Sanz-Montero, M.E., 2018. Biosedimentary and geochemical constraints on the precipitation of mineral crusts in shallow sulphate lakes. Sedimentary Geology 366, 32-46.Fischer, C., Luttge, A., 2018. Pulsating dissolution of crystalline matter. Proceedings of the National Academy of Sciences 115, 897-902.Islam, A., Chevalier, S., Sassi, M., 2018. Structural characterization and numerical simulations of flow properties of standard and reservoir carbonate rocks using micro-tomography. Computers & Geosciences 113, 14-22.Macgregor, D., 2018. History of the development of Permian–Cretaceous rifts in East Africa: a series of interpreted maps through time. Petroleum Geoscience 24, 8-20.Macgregor, D., Argent, J., Sansom, P., 2018. Introduction to the thematic set: Tectonics and petroleum systems of East Africa. Petroleum Geoscience 24, 3-7.Purcell, P.G., 2018. Re-imagining and re-imaging the development of the East African Rift. Petroleum Geoscience 24, 21-40.Reeves, C.V., 2018. The development of the East African margin during Jurassic and Lower Cretaceous times: a perspective from global tectonics. Petroleum Geoscience 24, 41-56.Wang, S., Yang, P., Yang, Z., 2018. Characterization of freeze–thaw effects within clay by 3D X-ray Computed Tomography. Cold Regions Science and Technology 148, 13-21.Yang, C., Hou, L., Yang, F., Luo, X., Wang, J., 2017. Controlling factors of volcanic hydrocarbon reservoirs in Bohai Bay Basin, China. Journal of Natural Gas Geoscience 2, 219-228.You, X.L., Sun, S., Lin, C.S., Zhu, J.Q., 2018. Microbial dolomite in the sabkha environment of the middle Cambrian in the Tarim Basin, NW China. Australian Journal of Earth Sciences 65, 109-120.Zhang, K., Guo, Y., Bai, G., Wang, Z., Fan, B., Wu, J., Niu, X., 2018. Pore-structure characterization of the Eocene Sha-3 sandstones in the Bohai Bay Basin, China. Energy & Fuels 32, 1579-1591.Zhu, H., Zhong, D., Zhang, T., Liu, G., Yao, J., He, C., 2018. Diagenetic controls on the reservoir quality of fine-grained “tight” sandstones: A case study based on NMR analysis. Energy & Fuels 32, 1612-1623.Bolide Impacts/Crater GeochemistryCavosie, A.J., Timms, N.E., Erickson, T.M., Koeberl, C., 2018. New clues from Earth’s most elusive impact crater: Evidence of reidite in Australasian tektites from Thailand. Geology 46, 203-206.HydratesAjayi, T., Anderson, B.J., Seol, Y., Boswell, R., Myshakin, E.M., 2018. Key aspects of numerical analysis of gas hydrate reservoir performance: Alaska North Slope Prudhoe Bay Unit “L-Pad” hydrate accumulation. Journal of Natural Gas Science and Engineering 51, 37-43.Chen, X., Verma, R., Espinoza, D.N., Prodanovi?, M., 2018. Pore-scale determination of gas relative permeability in hydrate-bearing sediments using X-ray computed micro-tomography and lattice Boltzmann method. Water Resources Research 54, 600-608.Guan, J.-a., Liang, D., 2018. Discussion on the rapid formation mechanism and evolution process of methane hydrate-bearing sediments in Shenhu Area of northern South China Sea. Marine and Petroleum Geology 91, 225-235.Karstens, J., Haflidason, H., Becker, L.W.M., Berndt, C., Rüpke, L., Planke, S., Liebetrau, V., Schmidt, M., Mienert, J., 2018. Glacigenic sedimentation pulses triggered post-glacial gas hydrate dissociation. Nature Communications 9, Article 635.Khan, M.N., Warrier, P., Peters, C.J., Koh, C.A., 2018. Advancements in hydrate phase equilibria and modeling of gas hydrates systems. Fluid Phase Equilibria 463, 48-61.Malinverno, A., Cook, A.E., Daigle, H., Oryan, B., 2018. Glacial cycles influence marine methane hydrate formation. Geophysical Research Letters 45, 724-732.Merey, ?., Longinos, S.N., 2018. Numerical simulations of gas production from Class 1 hydrate and Class 3 hydrate in the Nile Delta of the Mediterranean Sea. Journal of Natural Gas Science and Engineering 52, 248-266.Mu?oz-Iglesias, V., Choukroun, M., Vu, T.H., Hodyss, R., Mahjoub, A., Smythe, W.D., Sotin, C., 2018. Phase diagram of the ternary water–tetrahydrofuran–ammonia system at low temperatures. Implications for clathrate hydrates and outgassing on Titan. ACS Earth and Space Chemistry 2, 135-146.Wang, J., Zhang, L., Zhao, J., Ai, L., Yang, L., 2018. Variations in permeability along with interfacial tension in hydrate-bearing porous media. Journal of Natural Gas Science and Engineering 51, 141-146.Wu, Z., Li, Y., Sun, X., Li, M., Jia, R., 2018. Experimental study on the gas phase permeability of montmorillonite sediments in the presence of hydrates. Marine and Petroleum Geology 91, 373-380.Zhao, J., Zhao, Y., Liang, W., Song, S., Gao, Q., 2018. Semi-clathrate hydrate process of methane in porous media-mesoporous materials of SBA-15. Fuel 220, 446-452.Zheng, R., Li, S., Li, X., 2018. Sensitivity analysis of hydrate dissociation front conditioned to depressurization and wellbore heating. Marine and Petroleum Geology 91, 631-638.Isotope GeochemistryBrodie, M.W., Aplin, A.C., Hart, B., Orland, I.J., Valley, J.W., Boyce, A.J., 2018. Oxygen isotope microanalysis by secondary ion mass spectrometry suggests continuous 300-million-year history of calcite cementation and dolomitization in the Devonian Bakken Formation. Journal of Sedimentary Research 88, 91-104.Feng, D., Peckmann, J., Li, N., Kiel, S., Qiu, J.-W., Liang, Q., Carney, R.S., Peng, Y., Tao, J., Chen, D., 2018. The stable isotope fingerprint of chemosymbiosis in the shell organic matrix of seep-dwelling bivalves. Chemical Geology 479, 241-250.Goswami, V., Hannah, J.L., Stein, H.J., 2018. Why terrestrial coals cannot be dated using the Re-Os geochronometer: Evidence from the Finnmark Platform, southern Barents Sea and the Fire Clay coal horizon, Central Appalachian Basin. International Journal of Coal Geology 188, 121-135.Graf, J., Tabor, N.J., Ferguson, K., Winkler, D.A., Lee, Y.-N., May, S., Jacobs, L.L., 2018. Diagenesis of dinosaur eggshell from the Gobi Desert, Mongolia. Palaeogeography, Palaeoclimatology, Palaeoecology 494, 65-74.Huang, X., Zhao, B., Wang, K., Hu, Y., Meyers, P.A., 2018. Seasonal variations of leaf wax n-alkane molecular composition and δD values in two subtropical deciduous tree species: Results from a three-year monitoring program in central China. Organic Geochemistry 118, 15-26.Li, W., Zhu, Y.-M., Liu, Y., 2018. Gas evolution and isotopic fractionations during pyrolysis on coals of different ranks. International Journal of Coal Geology 188, 136-144.Liu, Q., Jin, Z., Wang, X., Yi, J., Meng, Q., Wu, X., Gao, B., Nie, H., Zhu, D., 2018. Distinguishing kerogen and oil cracked shale gas using H, C-isotopic fractionation of alkane gases. Marine and Petroleum Geology 91, 350-362.Lueders-Dumont, J.A., Wang, X.T., Jensen, O.P., Sigman, D.M., Ward, B.B., 2018. Nitrogen isotopic analysis of carbonate-bound organic matter in modern and fossil fish otoliths. Geochimica et Cosmochimica Acta 224, 200-222.Morée, A.L., Schwinger, J., Heinze, C., 2018. Southern Ocean controls of the vertical marine δ13C gradient – a modelling study. Biogeosciences Discussions 2018, 1-24.Oczkowski, A., Taplin, B., Pruell, R., Pimenta, A., Johnson, R., Grear, J., 2018. Carbon stable isotope values in plankton and mussels reflect changes in carbonate chemistry associated with nutrient enhanced net production. Frontiers in Marine Science 5, 43. doi: 10.3389/fmars.2018.00043.Robu, M., Wynn, J.G., Mirea, I.C., Petculescu, A., Kenesz, M., Pu?ca?, C.M., Vlaicu, M., Trinkaus, E., Constantin, S., 2018. The diverse dietary profiles of MIS 3 cave bears from the Romanian Carpathians: insights from stable isotope (δ13C and δ15N) analysis. Palaeontology 61, 209-219.Rolison, J.M., Stirling, C.H., Middag, R., Gault-Ringold, M., George, E., Rijkenberg, M.J.A., 2018. Iron isotope fractionation during pyrite formation in a sulfidic Precambrian ocean analogue. Earth and Planetary Science Letters 488, 1-13.Sutton, J.N., André, L., Cardinal, D., Conley, D.J., de Souza, G.F., Dean, J., Dodd, J., Ehlert, C., Ellwood, M.J., Frings, P.J., Grasse, P., Hendry, K., Leng, M.J., Michalopoulos, P., Panizzo, V.N., Swann, G.E.A., 2018. A review of the stable isotope bio-geochemistry of the global silicon cycle and its associated trace elements. Frontiers in Earth Science 5, 112. doi: 110.3389/feart.2017.00112.Zhang, D., Feng, Z., Yang, Y., Lan, B., Ran, M., Mu, G., 2018. Peat δ13Ccelluose-recorded wetting trend during the past 8000?years in the southern Altai Mountains, northern Xinjiang, NW China. Journal of Asian Earth Sciences 156, 174-179.Zhang, Q., Amor, K., Galer, S.J.G., Thompson, I., Porcelli, D., 2018. Variations of stable isotope fractionation during bacterial chromium reduction processes and their implications. Chemical Geology 481, 155-164.Clumped IsotopesEvans, D., Sagoo, N., Renema, W., Cotton, L.J., Müller, W., Todd, J.A., Saraswati, P.K., Stassen, P., Ziegler, M., Pearson, P.N., Valdes, P.J., Affek, H.P., 2018. Eocene greenhouse climate revealed by coupled clumped isotope-Mg/Ca thermometry. Proceedings of the National Academy of Sciences 115, 1174-1179.Pagel, M., Bonifacie, M., Schneider, D.A., Gautheron, C., Brigaud, B., Calmels, D., Cros, A., Saint-Bezar, B., Landrein, P., Sutcliffe, C., Davis, D., Chaduteau, C., 2018. Improving paleohydrological and diagenetic reconstructions in calcite veins and breccia of a sedimentary basin by combining Δ47 temperature, δ18Owater and U-Pb age. Chemical Geology 481, 1-17.Zhang, L., Wang, C., Wignall, P.B., Kluge, T., Wan, X., Wang, Q., Gao, Y., 2018. Deccan volcanism caused coupled pCO2 and terrestrial temperature rises, and pre-impact extinctions in northern China. Geology 46, 271-274.Methods/InstrumentationHeuillet, M., Bellvert, F., Cahoreau, E., Letisse, F., Millard, P., Portais, J.-C., 2018. Methodology for the validation of isotopic analyses by mass spectrometry in stable-isotope labeling experiments. Analytical Chemistry 90, 1852-1860.Khodjaniyazova, S., Nazari, M., Garrard, K.P., Matos, M.P.V., Jackson, G.P., Muddiman, D.C., 2018. Characterization of the spectral accuracy of an Orbitrap mass analyzer using isotope ratio mass spectrometry. Analytical Chemistry 90, 1897-1906.Kurek, M.R., Gilhooly, W.P., Druschel, G.K., O'Beirne, M.D., Werne, J.P., 2018. The use of dithiothreitol for the quantitative analysis of elemental sulfur concentrations and isotopes in environmental samples. Chemical Geology 481, 18-26.Mathematical Geochemistry/Phase BehaviorAzinfar, B., Haddadnia, A., Zirrahi, M., Hassanzadeh, H., Abedi, J., 2018. Phase behaviour of butane/bitumen fractions: Experimental and modeling studies. Fuel 220, 47-59.Richardson, I.A., Hartwig, J.W., Leachman, J.W., 2018. Experimental PρT-x measurements of liquid methane-ethane-nitrogen mixtures. Fluid Phase Equilibria 462, 38-43.Santos, M.S., Franco, L.F.M., Castier, M., Economou, I.G., 2018. Molecular dynamics simulation of n-alkanes and CO2 confined by calcite nanopores. Energy & Fuels 32, 1934-1941.Microbiology/ExtremophilesDi Donato, P., Romano, I., Mastascusa, V., Poli, A., Orlando, P., Pugliese, M., Nicolaus, B., 2018. Survival and adaptation of the thermophilic species Geobacillus thermantarcticus in simulated spatial conditions. Origins of Life and Evolution of Biospheres 48, 141-158.Edwardson, C.F., Hollibaugh, J.T., 2018. Composition and activity of microbial communities along the redox gradient of an alkaline, hypersaline, lake. Frontiers in Microbiology 9, 14. doi: 10.3389/fmicb.2018.00014.Torregrosa-Crespo, J., Bergaust, L., Pire, C., Martínez-Espinosa, R.M., 2018. Denitrifying haloarchaea: sources and sinks of nitrogenous gases. FEMS Microbiology Letters 365, Article fnx270.Zhang, Y., Bach, L.T., Lohbeck, K.T., Schulz, K.G., Listmann, L., Klapper, R., Riebesell, U., 2018. Population-specific responses in physiological rates of Emiliania huxleyi to a broad CO2 range. Biogeosciences Discussions 2018, 1-35.Zhao, B., Hu, Q., Guo, X., Liao, Z., Sarmiento, F., Mesbah, N.M., Yan, Y., Li, J., Wiegel, J., 2018. Natronolimnobius aegyptiacus sp. nov., an extremely halophilic alkalithermophilic archaeon isolated from the athalassohaline Wadi An Natrun, Egypt. International Journal of Systematic and Evolutionary Microbiology 68, 498-506.Microbial EcosystemsBock, N., Van Wambeke, F., Dion, M., Duhamel, S., 2018. Microbial community structure in the Western Tropical South Pacific. Biogeosciences Discussions 2018, 1-24.Buttigieg, P.L., Fadeev, E., Bienhold, C., Hehemann, L., Offre, P., Boetius, A., 2018. Marine microbes in 4D — using time series observation to assess the dynamics of the ocean microbiome and its links to ocean health. Current Opinion in Microbiology 43, 169-185.Dhami, N.K., Mukherjee, A., Watkin, E.L.J., 2018. Microbial diversity and mineralogical-mechanical properties of calcitic cave speleothems in natural and in vitro biomineralization conditions. Frontiers in Microbiology 9, 40. doi: 10.3389/fmicb.2018.00040.Escudero, C., Vera, M., Oggerin, M., Amils, R., 2018. Active microbial biofilms in deep poor porous continental subsurface rocks. Scientific Reports 8, Article 1538.Fortunato, C.S., Larson, B., Butterfield, D.A., Huber, J.A., 2018. Spatially distinct, temporally stable microbial populations mediate biogeochemical cycling at and below the seafloor in hydrothermal vent fluids. Environmental Microbiology 20, 769-784.Frouin, E., Bes, M., Ollivier, B., Quéméneur, M., Postec, A., Debroas, i., Armougom, F., Erauso, G., 2018. Diversity of rare and abundant prokaryotic phylotypes in the Prony Hydrothermal Field and comparison with other serpentinite-hosted ecosystems. Frontiers in Microbiology 9, 102. doi: 110.3389/fmicb.2018.00102.Gonzalez-Martinez, A., Sihvonen, M., Mu?oz-Palazon, B., Rodriguez-Sanchez, A., Mikola, A., Vahala, R., 2018. Microbial ecology of full-scale wastewater treatment systems in the Polar Arctic Circle: Archaea, Bacteria and Fungi. Scientific Reports 8, Article 2208.Gonzalez-Pimentel, J.L., Miller, A.Z., Jurado, V., Laiz, L., Pereira, M.F.C., Saiz-Jimenez, C., 2018. Yellow coloured mats from lava tubes of La Palma (Canary Islands, Spain) are dominated by metabolically active Actinobacteria. Scientific Reports 8, Article 1944.Hassanshahian, M., Ghoebani, S., 2018. Isolation and characterization of iron and sulfur-oxidizing bacteria from Maiduk copper mine at Shahrbabk Province in Iran. Geomicrobiology Journal 35, 261-265.He, H., Zhen, Y., Mi, T., Fu, L., Yu, Z., 2018. Ammonia-oxidizing archaea and bacteria differentially contribute to ammonia oxidation in sediments from adjacent waters of Rushan Bay, China. Frontiers in Microbiology 9, 116. doi: 110.3389/fmicb.2018.00116.Hu, Y., Cai, J., Bai, C., Shao, K., Tang, X., Gao, G., 2018. Contrasting patterns of the bacterial and archaeal communities in a high-elevation river in northwestern China. Journal of Microbiology 56, 104-112.Jansson, J.K., Hofmockel, K.S., 2018. The soil microbiome — from metagenomics to metaphenomics. Current Opinion in Microbiology 43, 162-168.Kato, S., Shibuya, T., Takaki, Y., Hirai, M., Nunoura, T., Suzuki, K., 2018. Genome-enabled metabolic reconstruction of dominant chemosynthetic colonizers in deep-sea massive sulfide deposits. Environmental Microbiology 20, 862-877.Li, M., Wei, G., Shi, W., Sun, Z., Li, H., Wang, X., Gao, Z., 2018. Distinct distribution patterns of ammonia-oxidizing archaea and bacteria in sediment and water column of the Yellow River estuary. Scientific Reports 8, Article 1584.Lin, X., Huang, R., Li, Y., Li, F., Wu, Y., Hutchins, D.A., Dai, M., Gao, K., 2018. Interactive network configuration maintains bacterioplankton community structure under elevated CO2 in a eutrophic coastal mesocosm experiment. Biogeosciences 15, 551-565.Mullineaux, L.S., Metaxas, A., Beaulieu, S.E., Bright, M., Gollner, S., Grupe, B.M., Herrera, S., Kellner, J.B., Levin, L.A., Mitarai, S., Neubert, M.G., Thurnherr, A.M., Tunnicliffe, V., Watanabe, H.K., Won, Y.-J., 2018. Exploring the ecology of deep-sea hydrothermal vents in a metacommunity framework. Frontiers in Marine Science 5, 49. doi: 10.3389/fmars.2018.00049.Park, Y., Kim, S., Cho, S., Cha, J., An, S., 2018. Microbial community structure and activity changes in response to the development of hypoxia in a shallow estuary. Biogeosciences Discussions 2018, 1-43.Quatrini, R., Johnson, D.B., 2018. Microbiomes in extremely acidic environments: functionalities and interactions that allow survival and growth of prokaryotes at low pH. Current Opinion in Microbiology 43, 139-147.Roush, D., Couradeau, E., Guida, B., Neuer, S., Garcia-Pichel, F., 2018. A new niche for anoxygenic phototrophs as endoliths. Applied and Environmental Microbiology 84, Article e02055-02017.Spirina, E.V., Durdenko, E.V., Demidov, N.E., Abramov, A.A., Romanovsky, V.E., Rivkina, E.M., 2017. Halophilic-psychrotrophic bacteria of an Alaskan cryopeg—a model for astrobiology. Paleontological Journal 51, 1440-1452.Suter, E.A., Pachiadaki, M., Taylor, G.T., Astor, Y., Edgcomb, V.P., 2018. Free-living chemoautotrophic and particle-attached heterotrophic prokaryotes dominate microbial assemblages along a pelagic redox gradient. Environmental Microbiology 20, 693-712.Tang, K., Zhang, Y., Lin, D., Han, Y., Chen, C.-T.A., Wang, D., Lin, Y.-S., Sun, J., Zheng, Q., Jiao, N., 2018. Cultivation-independent and cultivation-dependent analysis of microbes in the shallow-sea hydrothermal system off Kueishantao Island, Taiwan: Unmasking heterotrophic bacterial diversity and functional capacity. Frontiers in Microbiology 9, 279. doi: 210.3389/fmicb.2018.00279.Wierzchos, J., Casero, M.C., Artieda, O., Ascaso, C., 2018. Endolithic microbial habitats as refuges for life in polyextreme environment of the Atacama Desert. Current Opinion in Microbiology 43, 124-131.Xie, W., Luo, H., Murugapiran, S.K., Dodsworth, J.A., Chen, S., Sun, Y., Hedlund, B.P., Wang, P., Fang, H., Deng, M., Zhang, C.L., 2018. Localized high abundance of Marine Group II archaea in the subtropical Pearl River Estuary: implications for their niche adaptation. Environmental Microbiology 20, 734-754.Xie, Z.-X., Chen, F., Zhang, S.-F., Wang, M.-H., Zhang, H., Kong, L.-F., Dai, M.-H., Hong, H.-S., Lin, L., Wang, D.-Z., 2018. Metaproteomics of marine viral concentrates reveals key viral populations and abundant periplasmic proteins in the oligotrophic deep chlorophyll maximum of the South China Sea. Environmental Microbiology 20, 477-491.Xu, W., Gong, L.-f., Pang, K.-L., Luo, Z.-H., 2018. Fungal diversity in deep-sea sediments of a hydrothermal vent system in the Southwest Indian Ridge. Deep Sea Research Part I: Oceanographic Research Papers 131, 16-26.Yan, Y.-W., Jiang, Q.-Y., Wang, J.-G., Zhu, T., Zou, B., Qiu, Q.-F., Quan, Z.-X., 2018. Microbial communities and diversities in mudflat sediments analyzed using a modified metatranscriptomic method. Frontiers in Microbiology 9, 93. doi: 10.3389/fmicb.2018.00093.Zhang, W., Pan, Y., Yang, J., Chen, H., Holohan, B., Vaudrey, J., Lin, S., McManus, G.B., 2018. The diversity and biogeography of abundant and rare intertidal marine microeukaryotes explained by environment and dispersal limitation. Environmental Microbiology 20, 462-476.Petroleum DegradersBae, S.S., Jung, J., Chung, D., Baek, K., 2018. Marinobacterium aestuarii sp. nov., a benzene-degrading marine bacterium isolated from estuary sediment. International Journal of Systematic and Evolutionary Microbiology 68, 651-656.Chaudhary, D.K., Kim, J., 2018. Sphingobacterium terrae sp. nov., isolated from oil-contaminated soil. International Journal of Systematic and Evolutionary Microbiology 68, 609-615.Chaudhary, D.K., Kim, J., 2018. Tessaracoccus terricola sp. nov., isolated from oil-contaminated soil. International Journal of Systematic and Evolutionary Microbiology 68, 529-535.Derguine-Mecheri, L., Kebbouche-Gana, S., Khemili-Talbi, S., Djenane, D., 2018. Screening and biosurfactant/bioemulsifier production from a high-salt-tolerant halophilic Cryptococcus strain YLF isolated from crude oil. Journal of Petroleum Science and Engineering 162, 712-724.Fuertez, J., Córdoba, G., McLennan, J.D., Adams, D.J., Sparks, T.D., 2018. Potential application of developed methanogenic microbial consortia for coal biogasification. International Journal of Coal Geology 188, 165-180.Garrido-Sanz, D., Manzano, J., Martín, M., Redondo-Nieto, M., Rivilla, R., 2018. Metagenomic analysis of a biphenyl-degrading soil bacterial consortium reveals the metabolic roles of specific populations. Frontiers in Microbiology 9, 232. doi: 210.3389/fmicb.2018.00232.Luong, T.M., Ponamoreva, O.N., Nechaeva, I.A., Petrikov, K.V., Delegan, Y.A., Surin, A.K., Linklater, D., Filonov, A.E., 2018. Characterization of biosurfactants produced by the oil-degrading bacterium Rhodococcus erythropolis S67 at low temperature. World Journal of Microbiology and Biotechnology 34, 20.Mamet, S.D., Ma, B., Ulrich, A., Schryer, A., Siciliano, S.D., 2018. Who is the rock miner and who is the hunter? The use of heavy-oxygen labeled phosphate (P18O4) to differentiate between C and P fluxes in a benzene-degrading consortium. Environmental Science & Technology 52, 1773-1786.Okoro, C.C., Nwezza, E.E., Lin, J., 2018. Persistence of halophylic methanogens and oil-degrading bacteria in an offshore oil-producing facility. Geomicrobiology Journal 35, 323-333.Pham, V.H.T., Chaudhary, D.K., Jeong, S.-W., Kim, J., 2018. Oil-degrading properties of a psychrotolerant bacterial strain, Rhodococcus sp. Y2-2, in liquid and soil media. World Journal of Microbiology and Biotechnology 34, 33.Shinde, V.L., Meena, R.M., Shenoy, B.D., 2018. Phylogenetic characterization of culturable bacteria and fungi associated with tarballs from Betul beach, Goa, India. Marine Pollution Bulletin 128, 593-600.Subhash, Y., Lee, S.-S., 2018. Roseomonas deserti sp. nov., isolated from crude oil contaminated desert sand. International Journal of Systematic and Evolutionary Microbiology 68, 675-680.Xi, L., Qiao, N., Zhang, J., Li, J., Liu, D., You, J., Liu, J., 2018. Deinococcus petrolearius sp. nov. isolated from crude oil recovery water in China. Antonie van Leeuwenhoek 111, 353-360.Zheng, J., Feng, J.-Q., Zhou, L., Mbadinga, S.M., Gu, J.-D., Mu, B.-Z., 2018. Characterization of bacterial composition and diversity in a long-term petroleum contaminated soil and isolation of high-efficiency alkane-degrading strains using an improved medium. World Journal of Microbiology and Biotechnology 34, 34.Oil & Gas ExplorationDavison, I., Steel, I., 2018. Geology and hydrocarbon potential of the East African continental margin: a review. Petroleum Geoscience 24, 57-91.Hakimi, M.H., Najaf, A.A., Abdula, R.A., Mohialdeen, I.M.J., 2018. Generation and expulsion history of oil-source rock (Middle Jurassic Sargelu Formation) in the Kurdistan of north Iraq, Zagros folded belt: Implications from 1D basin modeling study. Journal of Petroleum Science and Engineering 162, 852-872.Liu, J., Jiang, Y., Liu, X., Zhu, R., 2018. Natural gas migration and accumulation model and favorable exploration targets in Ordovician dolomite in Jingxi, Ordos Basin. Energy Exploration & Exploitation 36, 373-387.Oil & Gas Generation/ExpulsionAljariri Alhesan, J.S., Fei, Y., Marshall, M., Jackson, W.R., Qi, Y., Chaffee, A.L., Cassidy, P.J., 2018. Long time, low temperature pyrolysis of El-Lajjun oil shale. Journal of Analytical and Applied Pyrolysis 130, 135-141.Blach, T., Radlinski, A.P., Edwards, D.S., Boreham, C.J., Rehm, C., de Campo, L., Gilbert, E.P., 2018. Fingerprint of hydrocarbon generation in the southern Georgina Basin, Australia, revealed by small angle neutron scattering. International Journal of Coal Geology 186, 135-144.Chang, Z., Chu, M., Zhang, C., Bai, S., Lin, H., Ma, L., 2018. Influence of inherent mineral matrix on the product yield and characterization from Huadian oil shale pyrolysis. Journal of Analytical and Applied Pyrolysis 130, 269-276.He, K., Zhang, S., Mi, J., Zhang, W., 2018. Pyrolysis involving n-hexadecane, water and minerals: Insight into the mechanisms and isotope fractionation for water-hydrocarbon reaction. Journal of Analytical and Applied Pyrolysis 130, 198-208.Li, W., Zhu, Y.-M., Liu, Y., 2018. Gas evolution and isotopic fractionations during pyrolysis on coals of different ranks. International Journal of Coal Geology 188, 136-144.Liu, Q., Jin, Z., Wang, X., Yi, J., Meng, Q., Wu, X., Gao, B., Nie, H., Zhu, D., 2018. Distinguishing kerogen and oil cracked shale gas using H, C-isotopic fractionation of alkane gases. Marine and Petroleum Geology 91, 350-362.Zhou, Y., Li, G., Jin, L., Zhou, J., Wang, J., Li, Y., Hu, H., 2018. In situ analysis of catalytic effect of calcium nitrate on Shenmu coal pyrolysis with pyrolysis vacuum ultraviolet photoionization mass spectrometry. Energy & Fuels 32, 1061-1069.Oil & Gas GeochemistryAkinola, A.S., Adebiyi, F.M., Santoro, A., Mastrolitti, S., 2018. Study of resin fraction of Nigerian crude oil using spectroscopic/spectrometric analytical techniques. Petroleum Science and Technology 36, 429-436.Araújo, B.Q., Aquino Neto, F.R., Azevedo, D.A., 2018. Occurrence of extended tetracyclic polyprenoid series in crude oils. Organic Geochemistry 118, 27-35.Burton, Z.F.M., Moldowan, J.M., Sykes, R., Graham, S.A., 2018. Unraveling petroleum degradation, maturity, and mixing and addressing impact on petroleum prospectivity: Insights from frontier exploration regions in New Zealand. Energy & Fuels 32, 1287-1296.Chang, Z., Zhang, W., Ge, X., Zhu, S., 2018. Use of light hydrocarbons for the oil-oil correlation in Pearl River Mouth Basin, South China Sea. Fuel 221, 179-187.Chen, J., Pang, X., Pang, H., Chen, Z., Jiang, C., 2018. Hydrocarbon evaporative loss evaluation of lacustrine shale oil based on mass balance method: Permian Lucaogou Formation in Jimusaer Depression, Junggar Basin. Marine and Petroleum Geology 91, 422-431.Han, Y., Zhang, Y., Xu, C., Hsu, C.S., 2018. Molecular characterization of sulfur-containing compounds in petroleum. Fuel 221, 144-158.Hur, M., Ware, R.L., Park, J., McKenna, A.M., Rodgers, R.P., Nikolau, B.J., Wurtele, E.S., Marshall, A.G., 2018. Statistically significant differences in composition of petroleum crude oils revealed by volcano plots generated from ultrahigh resolution Fourier transform ion cyclotron resonance mass spectra. Energy & Fuels 32, 1206-1212.Liu, Y., Tian, Y., Yang, C., Xiao, D., Liao, Q., Shen, C., Fan, Y., Tang, P., Pu, X., Jiang, W., 2017. Hydrocarbon phase limit and conversion process in the deep formation from Qikou Sag of Bohai Bay rift lacustrine basin, China. Journal of Natural Gas Geoscience 2, 229-238.Ma, A., Jin, Z., Zhu, C., Bai, Z., 2017. Cracking and thermal maturity of Ordovician oils from Tahe Oilfield, Tarim Basin, NW China. Journal of Natural Gas Geoscience 2, 239-252.Matapour, Z., Karlsen, D.A., 2018. Ages of Norwegian oils and bitumen based on age-specific biomarkers. Petroleum Geoscience 24, 92-101.Meng, Q., Wang, X., Wang, X., Lei, Y., Liu, P., Zhang, L., Jiang, C., Gao, C., 2018. Biodegradation of light hydrocarbon (C5-C8) in shale gases from the Triassic Yanchang Formation, Ordos basin, China. Journal of Natural Gas Science and Engineering 51, 183-194.Nowak, J.A., Shrestha, P.M., Weber, R.J., McKenna, A.M., Chen, H., Coates, J.D., Goldstein, A.H., 2018. Comprehensive analysis of changes in crude oil chemical composition during biosouring and treatments. Environmental Science & Technology 52, 1290-1300.Ostroukhov, S.B., 2018. Genesis of higher petroleum alkyltoluenes. Petroleum Chemistry 58, 8-12.Shen, W., Pang, X., Chen, J., Zhang, K., Chen, Z., Gao, Z., Luo, G., He, L., 2018. Ordovician hydrocarbon migration along the Tazhong No. 10 fault belt in the Tazhong Uplift, Tarim Basin, northwest China. Energy & Fuels 32, 1474-1490.Smirnov, M.B., Poludetkina, E.N., 2018. Characteristics of sources of oils of Romashkino field by composition of saturated and aromatic biomarkers. Geochemistry International 56, 162-170.Wang, Y., Chen, J., Pang, X., Zhang, B., Chen, Z., Zhang, G., Luo, G., He, L., 2018. Origin of deep sour natural gas in the Ordovician carbonate reservoir of the Tazhong Uplift, Tarim Basin, northwest China: Insights from gas geochemistry and formation water. Marine and Petroleum Geology 91, 532-549.Wang, Y., Chen, J., Pang, X., Zhang, B., Wang, Y., He, L., Chen, Z., Zhang, G., 2018. Anomalies of natural gas compositions and carbon isotope ratios caused by gas diffusion – A case from the Donghe Sandstone reservoir in the Hadexun Oilfield, Tarim Basin, northwest China. Journal of Asian Earth Sciences 156, 75-89.Yang, C., Ni, Z., Li, M., Wang, T., Chen, Z., Hong, H., Tian, X., 2018. Pyrobitumen in South China: Organic petrology, chemical composition and geological significance. International Journal of Coal Geology 188, 51-63.Yang, I.H., Lee, H.S., 2018. Desorbed gas volume estimation using conventional well-log data for the Montney Formation, Deep Basin, Canada. Journal of Petroleum Science and Engineering 162, 633-651.Paleoclimatology/PalaeocenographyEvans, D., Sagoo, N., Renema, W., Cotton, L.J., Müller, W., Todd, J.A., Saraswati, P.K., Stassen, P., Ziegler, M., Pearson, P.N., Valdes, P.J., Affek, H.P., 2018. Eocene greenhouse climate revealed by coupled clumped isotope-Mg/Ca thermometry. Proceedings of the National Academy of Sciences 115, 1174-1179.Fantasia, A., F?llmi, K.B., Adatte, T., Spangenberg, J.E., Montero-Serrano, J.-C., 2018. The Early Toarcian oceanic anoxic event: Paleoenvironmental and paleoclimatic change across the Alpine Tethys (Switzerland). Global and Planetary Change 162, 53-68.Giorio, C., Kehrwald, N., Barbante, C., Kalberer, M., King, A.C.F., Thomas, E.R., Wolff, E.W., Zennaro, P., 2018. Prospects for reconstructing paleoenvironmental conditions from organic compounds in polar snow and ice. Quaternary Science Reviews 183, 1-22.Huang, X., Zhao, B., Wang, K., Hu, Y., Meyers, P.A., 2018. Seasonal variations of leaf wax n-alkane molecular composition and δD values in two subtropical deciduous tree species: Results from a three-year monitoring program in central China. Organic Geochemistry 118, 15-26.Izumi, K., Endo, K., Kemp, D.B., Inui, M., 2018. Oceanic redox conditions through the late Pliensbachian to early Toarcian on the northwestern Panthalassa margin: Insights from pyrite and geochemical data. Palaeogeography, Palaeoclimatology, Palaeoecology 493, 1-10.Jing, D., Bainian, S., 2018. Early Cretaceous atmospheric CO2 estimates based on stomatal index of Pseudofrenelopsis papillosa (Cheirolepidiaceae) from southeast China. Cretaceous Research 85, 232-242.Keery, J.S., Holden, P.B., Edwards, N.R., 2018. Sensitivity of the Eocene climate to CO2 and orbital variability. Climate of the Past 14, 215-238.K?seo?lu, D., Belt, S.T., Smik, L., Yao, H., Panieri, G., Knies, J., 2018. Complementary biomarker-based methods for characterising Arctic sea ice conditions: A case study comparison between multivariate analysis and the PIP25 index. Geochimica et Cosmochimica Acta 222, 406-420.Madhavaraju, J., Lee, Y.I., Scott, R.W., González-León, C.M., Jenkyns, H.C., Saucedo-Samaniego, J.C., Ramasamy, S., 2018. High-resolution carbonate isotopic study of the Mural Formation (Cerro Pimas section), Sonora, México: Implications for early Albian oceanic anoxic events. Journal of South American Earth Sciences 82, 329-345.Rees-Owen, R.L., Gill, F.L., Newton, R.J., Ivanovi?, R.F., Francis, J.E., Riding, J.B., Vane, C.H., Lopes dos Santos, R.A., 2018. The last forests on Antarctica: Reconstructing flora and temperature from the Neogene Sirius Group, Transantarctic Mountains. Organic Geochemistry 118, 4-14.Rehfeld, K., Münch, T., Ho, S.L., Laepple, T., 2018. Global patterns of declining temperature variability from the Last Glacial Maximum to the Holocene. Nature 554, 356.Rontani, J.-F., Belt, S.T., Amiraux, R., 2018. Biotic and abiotic degradation of the sea ice diatom biomarker IP25 and selected algal sterols in near-surface Arctic sediments. Organic Geochemistry 118, 73-88.Rudmin, M., Roberts, A.P., Horng, C.-S., Mazurov, A., Savinova, O., Ruban, A., Kashapov, R., Veklich, M., 2018. Ferrimagnetic iron sulfide formation and methane venting across the Paleocene-Eocene Thermal Maximum in shallow marine sediments, ancient West Siberian Sea. Geochemistry, Geophysics, Geosystems 19, 21-42.Scheiner, F., Holcová, K., Milovsk?, R., Kuhnert, H., 2018. Temperature and isotopic composition of seawater in the epicontinental sea (Central Paratethys) during the Middle Miocene Climate Transition based on Mg/Ca, δ18O and δ13C from foraminiferal tests. Palaeogeography, Palaeoclimatology, Palaeoecology 495, 60-71.Si, W., Aubry, M.-P., 2018. Vital effects and ecologic adaptation of photosymbiont-bearing planktonic foraminifera during the Paleocene-Eocene Thermal Maximum, implications for paleoclimate. Paleoceanography and Paleoclimatology 33, 112-125.van der Bilt, W.G.M., D'Andrea, W.J., Bakke, J., Balascio, N.L., Werner, J.P., Gjerde, M., Bradley, R.S., 2018. Alkenone-based reconstructions reveal four-phase Holocene temperature evolution for High Arctic Svalbard. Quaternary Science Reviews 183, 204-213.Westerhold, T., R?hl, U., Donner, B., Frederichs, T., Kordesch, W.E.C., Bohaty, S.M., Hodell, D.A., Laskar, J., Zeebe, R.E., 2018. Late Lutetian Thermal Maximum—Crossing a thermal threshold in Earth's climate system? Geochemistry, Geophysics, Geosystems 19, 73-82.Zhang, D., Feng, Z., Yang, Y., Lan, B., Ran, M., Mu, G., 2018. Peat δ13Ccelluose-recorded wetting trend during the past 8000?years in the southern Altai Mountains, northern Xinjiang, NW China. Journal of Asian Earth Sciences 156, 174-179.Extinction EventsBenca, J.P., Duijnstee, I.A.P., Looy, C.V., 2018. UV-B–induced forest sterility: Implications of ozone shield failure in Earth’s largest extinction. Science Advances 4, Article e1700618.Byrnes, J.S., Karlstrom, L., 2018. Anomalous K-Pg–aged seafloor attributed to impact-induced mid-ocean ridge magmatism. Science Advances 4, Article eaao2994.Cione, A.L., Santillana, S., Gouiric-Cavalli, S., Acosta Hospitaleche, C., Gelfo, J.N., López, G.M., Reguero, M., 2018. Before and after the K/Pg extinction in West Antarctica: New marine fish records from Marambio (Seymour) Island. Cretaceous Research 85, 250-265.Keller, G., Mateo, P., Punekar, J., Khozyem, H., Gertsch, B., Spangenberg, J., Bitchong, A.M., Adatte, T., 2018. Environmental changes during the Cretaceous-Paleogene mass extinction and Paleocene-Eocene Thermal Maximum: Implications for the Anthropocene. Gondwana Research 56, 69-89.Kiessling, W., Schobben, M., Ghaderi, A., Hairapetian, V., Leda, L., Korn, D., 2018. Pre–mass extinction decline of latest Permian ammonoids. Geology 46, 283-286.Luppo, T., López de Luchi, M.G., Rapalini, A.E., Martínez Dopico, C.I., Fanning, C.M., 2018. Geochronologic evidence of a large magmatic province in northern Patagonia encompassing the Permian-Triassic boundary. Journal of South American Earth Sciences 82, 346-355.Rampino, M.R., Caldeira, K., 2018. Comparison of the ages of large-body impacts, flood-basalt eruptions, ocean-anoxic events and extinctions over the last 260 million years: a statistical study. International Journal of Earth Sciences 107, 601-606.Wolbach, W.S., Ballard, J.P., Mayewski, P.A., Adedeji, V., Bunch, T.E., Firestone, R.B., French, T.A., Howard, G.A., Israde-Alcántara, I., Johnson, J.R., Kimbel, D., Kinzie, C.R., Kurbatov, A., Kletetschka, G., LeCompte, M.A., Mahaney, W.C., Melott, A.L., Maiorana-Boutilier, A., Mitra, S., Moore, C.R., Napier, W.M., Parlier, J., Tankersley, K.B., Thomas, B.C., Wittke, J.H., West, A., Kennett, J.P., 2018. Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ～12,800 years ago. 1. Ice cores and glaciers. The Journal of Geology 126, 165-184.Wolbach, W.S., Ballard, J.P., Mayewski, P.A., Parnell, A.C., Cahill, N., Adedeji, V., Bunch, T.E., Domínguez-Vázquez, G., Erlandson, J.M., Firestone, R.B., French, T.A., Howard, G., Israde-Alcántara, I., Johnson, J.R., Kimbel, D., Kinzie, C.R., Kurbatov, A., Kletetschka, G., LeCompte, M.A., Mahaney, W.C., Melott, A.L., Mitra, S., Maiorana-Boutilier, A., Moore, C.R., Napier, W.M., Parlier, J., Tankersley, K.B., Thomas, B.C., Wittke, J.H., West, A., Kennett, J.P., 2018. Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ～12,800 years ago. 2. Lake, marine, and terrestrial sediments. The Journal of Geology 126, 185-205.Zaffani, M., Jadoul, F., Rigo, M., 2018. A new Rhaetian δ13Corg record: Carbon cycle disturbances, volcanism, End-Triassic mass Extinction (ETE). Earth-Science Reviews 178, 92-104.Zhang, L., Wang, C., Wignall, P.B., Kluge, T., Wan, X., Wang, Q., Gao, Y., 2018. Deccan volcanism caused coupled pCO2 and terrestrial temperature rises, and pre-impact extinctions in northern China. Geology 46, 271-274.Zhang, Y., Wen, H., Zhu, C., Fan, H., Cloquet, C., 2018. Cadmium isotopic evidence for the evolution of marine primary productivity and the biological extinction event during the Permian-Triassic crisis from the Meishan section, South China. Chemical Geology 481, 110-118.Precambrian GeochemistryRolison, J.M., Stirling, C.H., Middag, R., Gault-Ringold, M., George, E., Rijkenberg, M.J.A., 2018. Iron isotope fractionation during pyrite formation in a sulfidic Precambrian ocean analogue. Earth and Planetary Science Letters 488, 1-13.Sun, J., Zhu, X., Li, Z., 2018. Confirmation and global significance of a large-scale early Neoproterozoic banded iron formation on Hainan Island, China. Precambrian Research 307, 82-anics/Microfossils/Microbial EvolutionAoyama, S., Ueno, Y., 2018. Multiple sulfur isotope constraints on microbial sulfate reduction below an Archean seafloor hydrothermal system. Geobiology 16, 107-120.Bobrovskiy, I., Hope, J.M., Krasnova, A., Ivantsov, A., Brocks, J.J., 2018. Molecular fossils from organically preserved Ediacara biota reveal cyanobacterial origin for Beltanelliformis. Nature Ecology & Evolution 2, 437-440.Hallberg, R.O., Broman, C., 2018. Microbial fossils in the 2.63 Ga Jeerinah Formation, Western Australia—Evidence of microbial oxidation. Geomicrobiology Journal 35, 255-260.Jackson, T.A., 2018. Variations in the properties of extractable “humic matter” and associated kerogen in sediments through geologic time: Their significance for Precambrian biological evolution and paleoecology. Geomicrobiology Journal 35, 334-353.Marin-Carbonne, J., Remusat, L., Sforna, M.C., Thomazo, C., Cartigny, P., Philippot, P., 2018. Sulfur isotope's signal of nanopyrites enclosed in 2.7 Ga stromatolitic organic remains reveal microbial sulfate reduction. Geobiology 16, 121-138.Sallstedt, T., Bengtson, S., Broman, C., Crill, P.M., Canfield, D.E., 2018. Evidence of oxygenic phototrophy in ancient phosphatic stromatolites from the Paleoproterozoic Vindhyan and Aravalli Supergroups, India. Geobiology 16, 139-159.Wacey, D., Saunders, M., Kong, C., 2018. Remarkably preserved tephra from the 3430 Ma Strelley Pool Formation, Western Australia: Implications for the interpretation of Precambrian microfossils. Earth and Planetary Science Letters 487, 33-43.Wacey, D., Urosevic, L., Saunders, M., George, A.D., 2018. Mineralisation of filamentous cyanobacteria in Lake Thetis stromatolites, Western Australia. Geobiology 16, 203-215.Paleoclimatology/PaleocenographyBechst?dt, T., J?ger, H., Rittersbacher, A., Schweisfurth, B., Spence, G., Werner, G., Boni, M., 2018. The Cryogenian Ghaub Formation of Namibia – New insights into Neoproterozoic glaciations. Earth-Science Reviews 177, 678-714.Caxito, F.A., Frei, R., Uhlein, G.J., Gon?alves Dias, T., ?rting, T.B., Uhlein, A., 2018. Multiproxy geochemical and isotope stratigraphy records of a Neoproterozoic Oxygenation Event in the Ediacaran Sete Lagoas cap carbonate, Bambuí Group, Brazil. Chemical Geology 481, 119-132.Eickmann, B., Hofmann, A., Wille, M., Bui, T.H., Wing, B.A., Schoenberg, R., 2018. Isotopic evidence for oxygenated Mesoarchaean shallow oceans. Nature Geoscience 11, 133-138.Gao, Y., Zhang, X., Zhang, G., Chen, K., Shen, Y., 2018. Ediacaran negative C-isotopic excursions associated with phosphogenic events: Evidence from South China. Precambrian Research 307, 218-228.Gomes, M.L., 2018. An Archaean oxygen oasis. Nature Geoscience 11, 84-85.Large, R.R., Mukherjee, I., Zhukova, I., Corkrey, R., Stepanov, A., Danyushevsky, L.V., 2018. Role of upper-most crustal composition in the evolution of the Precambrian ocean–atmosphere system. Earth and Planetary Science Letters 487, 44-53.Shi, W., Li, C., Luo, G., Huang, J., Algeo, T.J., Jin, C., Zhang, Z., Cheng, M., 2018. Sulfur isotope evidence for transient marine-shelf oxidation during the Ediacaran Shuram Excursion. Geology 46, 267-270.Williams, G.E., Schmidt, P.W., 2018. Shuram–Wonoka carbon isotope excursion: Ediacaran revolution in the world ocean's meridional overturning circulation. Geoscience Frontiers 9, 391-402.Yang, X., Zhang, Z., Santosh, M., Duan, S., Liang, T., 2018. Anoxic to suboxic Mesoproterozoic ocean: Evidence from iron isotope and geochemistry of siderite in the Banded Iron Formations from North Qilian, NW China. Precambrian Research 307, 115-124.Crustal EvolutionAndrault, D., Pesce, G., Manthilake, G., Monteux, J., Bolfan-Casanova, N., Chantel, J., Novella, D., Guignot, N., King, A., Itié, J.-P., Hennet, L., 2018. Deep and persistent melt layer in the Archaean mantle. Nature Geoscience 11, 139-143.Ge, R., Zhu, W., Wilde, S.A., Wu, H., 2018. Remnants of Eoarchean continental crust derived from a subducted proto-arc. Science Advances 4, Article eaao3159.Parman, S., 2018. An Archaean mushy mantle. Nature Geoscience 11, 85-86.Spencer, C.J., Murphy, J.B., Kirkland, C.L., Liu, Y., Mitchell, R.N., 2018. A Palaeoproterozoic tectono-magmatic lull as a potential trigger for the supercontinent cycle. Nature Geoscience 11, 97-101.Production/Engineering GeochemistryAndrade, L.L.P.R., Rajagopal, K., 2018. Models for estimating the viscosity of paraffinic–naphthenic live crude oils. Energy & Fuels 32, 2622-2629.Cavalcante, C., de Oliveira, J.P., Hamada, J., de Siqueira, F.A., Nascimento, A.N.d., 2018. Sequential extraction procedure for the separation of Ni and V species in crude oil and analysis by ETAAS, GC–MS, and IR. Fuel 220, 631-637.Chang, X., Liang, J., Cui, J., Wang, T., 2018. Geochemical characterization of alteration of saturate fractions by water flooding. Acta Sedimentologica Sinica 36, 206-214.Chen, G., Lin, J., Hu, W., Cheng, C., Gu, X., Du, W., Zhang, J., Qu, C., 2018. Characteristics of a crude oil composition and its in situ waxing inhibition behavior. Fuel 218, 213-217.Cui, C., Billa, T., Zhang, L., Shi, Q., Zhao, S., Klein, M.T., Xu, C., 2018. Molecular representation of the petroleum gasoline fraction. Energy & Fuels 32, 1525-1533.Du, E., Zhao, Q., Xiao, Y., Cai, L., Tao, R., 2018. Electric field suppressed turbulence and reduced viscosity of asphaltene base crude oil sample. Fuel 220, 358-362.Gubernat, M., Fraczek-Szczypta, A., Tomala, J., Blazewicz, S., 2018. Catalytic effect of montmorillonite nanoparticles on thermal decomposition of coal tar pitch to carbon. Journal of Analytical and Applied Pyrolysis 130, 90-98.Lemos, B.C., Gilles, V., Gon?alves, G.R., de Castro, E.V.R., Delarmelina, M., Carneiro, J.W.d.M., Greco, S.J., 2018. Synthesis, structure-activity relationship and evaluation of new non-polymeric chemical additives based on naphthoquinone derivatives as wax precipitation inhibitors and pour point depressants to petroleum. Fuel 220, 200-209.Li, J., Wang, X., Wang, B., Zhao, J., Fang, Y., 2018. Investigation on the fates of vanadium and nickel during co-gasification of petroleum coke with biomass. Bioresource Technology 257, 47-53.Li, M., Wang, T.G., Xiao, Z., Fang, R., Ni, Z., Deng, W., Tang, Y., Zhang, C., Yang, L., 2018. Practical application of reservoir geochemistry in petroleum exploration: Case study from a Paleozoic carbonate reservoir in the Tarim Basin (northwestern China). Energy & Fuels 32, 1230-1241.Liang, Z., Chen, L., Alam, M.S., Zeraati Rezaei, S., Stark, C., Xu, H., Harrison, R.M., 2018. Comprehensive chemical characterization of lubricating oils used in modern vehicular engines utilizing GC?×?GC-TOFMS. Fuel 220, 792-799.Ristic, N.D., Djokic, M.R., Delbeke, E., Gonzalez-Quiroga, A., Stevens, C.V., Van Geem, K.M., Marin, G.B., 2018. Compositional characterization of pyrolysis fuel oil from naphtha and vacuum gas oil. Energy & Fuels 32, 1276-1286.Sakurovs, R., Koval, L., Grigore, M., Sokolova, A., de Campo, L., Rehm, C., 2018. Nanostructure of cokes. International Journal of Coal Geology 188, 112-120.AsphaltenesBoytsova, A., Kondrasheva, N., Ancheyta, J., 2018. Pyrolysis kinetics of heavy oil asphaltenes under steam atmosphere at different pressures. Energy & Fuels 32, 1132-1138.Chen, L., Meyer, J., Campbell, T., Canas, J., Betancourt, S.S., Dumont, H., Forsythe, J.C., Mehay, S., Kimball, S., Hall, D.L., Nighswander, J., Peters, K.E., Zuo, J.Y., Mullins, O.C., 2018. Applicability of simple asphaltene thermodynamics for asphaltene gradients in oilfield reservoirs: The Flory-Huggins-Zuo Equation of State with the Yen-Mullins model. Fuel 221, 216-232.Chibiryaev, A.M., Kozhevnikov, I.V., Shalygin, A.S., Martyanov, O.N., 2018. Transformation of petroleum asphaltenes in supercritical alcohols studied via FTIR and NMR techniques. Energy & Fuels 32, 2117-2127.Ezeonyeka, N.L., Hemmati-Sarapardeh, A., Husein, M.M., 2018. Asphaltenes adsorption onto metal oxide nanoparticles: A critical evaluation of measurement techniques. Energy & Fuels 32, 2213-2223.Khormali, A., Sharifov, A.R., Torba, D.I., 2018. The control of asphaltene precipitation in oil wells. Petroleum Science and Technology 36, 443-449.Koolen, H.H.F., Gomes, A.F., de Moura, L.G.M., Marcano, F., Cardoso, F.M.R., Klitzke, C.F., Wojcik, R., Binkley, J., Patrick, J.S., Swarthout, R.F., Rosa, P.T.V., Gozzo, F.C., 2018. Integrative mass spectrometry strategy for fingerprinting and tentative structural characterization of asphaltenes. Fuel 220, 717-724.Li, Y., Han, S., Lu, Y., Zhang, J., 2018. Influence of asphaltene polarity on crystallization and gelation of waxy oils. Energy & Fuels 32, 1491-1497.Mazzeo, C.P.P., Stedille, F.A., Mansur, C.R.E., Ramos, A.C.S., Lucas, E.F., 2018. Flocculation of asphaltenes by polymers: Influence of polymer solubility conditions. Energy & Fuels 32, 1087-1095.Pudenzi, M.A., Santos, J.M., Wisniewski, A., Eberlin, M.N., 2018. Comprehensive characterization of asphaltenes by Fourier transform ion cyclotron resonance mass spectrometry precipitated under different n-alkanes solvents. Energy & Fuels 32, 1038-1046.Qi, Z., Abedini, A., Sharbatian, A., Pang, Y., Guerrero, A., Sinton, D., 2018. Asphaltene deposition during bitumen extraction with natural gas condensate and naphtha. Energy & Fuels 32, 1433-1439.Rocha, J.A., Baydak, E.N., Yarranton, H.W., 2018. What fraction of the asphaltenes stabilizes water-in-bitumen emulsions? Energy & Fuels 32, 1440-1450.Shikhov, I., Li, R., Arns, C.H., 2018. Relaxation and relaxation exchange NMR to characterise asphaltene adsorption and wettability dynamics in siliceous systems. Fuel 220, 692-705.Sj?vall, P., Pomerantz, A.E., Lu, X., Mullins, O.C., 2018. Time of flight-secondary ion mass spectrometry (TOF-SIMS) study of diverse asphaltenes. Fuel 220, 638-644.Taghavi, H., Ashoori, S., Mousavi, S.H., 2018. Analyzing electrical field effect on asphaltene deposition. Petroleum Science and Technology 36, 487-493.Taheri-Shakib, J., Shekarifard, A., Naderi, H., 2018. Analysis of the asphaltene properties of heavy crude oil under ultrasonic and microwave irradiation. Journal of Analytical and Applied Pyrolysis 129, 171-180.Taheri-Shakib, J., Shekarifard, A., Naderi, H., 2018. Experimental investigation of the asphaltene deposition in porous media: Accounting for the microwave and ultrasonic effects. Journal of Petroleum Science and Engineering 163, 453-462.Xu, L., Abedini, A., Qi, Z., Kim, M., Guerrero, A., Sinton, D., 2018. Pore-scale analysis of steam-solvent coinjection: azeotropic temperature, dilution and asphaltene deposition. Fuel 220 151–158.Interfaces/EORAlfarge, D., Wei, M., Bai, B., 2017. Data analysis for CO2-EOR in shale-oil reservoirs based on a laboratory database. Journal of Petroleum Science and Engineering 162, 697-711.AlHammadi, M., Mahzari, P., Sohrabi, M., 2018. Fundamental investigation of underlying mechanisms behind improved oil recovery by low salinity water injection in carbonate rocks. Fuel 220, 345-357.AlSumaiti, A.M., Hashmet, M.R., AlAmeri, W.S., Anto-Darkwah, E., 2018. Laboratory study of CO2 foam flooding in high temperature, high salinity carbonate reservoirs using co-injection technique. Energy & Fuels 32, 1416-1422.Babaei, M., Mu, J., Masters, A.J., 2018. Impact of variation in multicomponent diffusion coefficients and salinity in CO2-EOR: A numerical study using molecular dynamics simulation. Journal of Petroleum Science and Engineering 162, 685-696.Bazyari, A., Jamialahmadi, M., Soltani Soulgani, B., Zeinijahromi, A., 2018. Evaluation of enhanced oil recovery from clay-rich sandstone formations. Petroleum Science and Technology 36, 405-410.Daryasafar, N., Borazjani, O., Daryasafar, A., 2018. Adsorption of natural surfactants on sandstone rocks: Effect on the quality of the recovered asphaltenic oil. Petroleum Science and Technology 36, 525-530.Karambeigi, M.S., Asl, A.H., Nasiri, M., 2018. Multi-objective optimization of microemulsion flooding for chemical enhanced oil recovery. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 73, Article 4.Ke, C.-Y., Lu, G.-M., Li, Y.-B., Sun, W.-J., Zhang, Q.-Z., Zhang, X.-L., 2018. A pilot study on large-scale microbial enhanced oil recovery (MEOR) in Baolige Oilfield. International Biodeterioration & Biodegradation 127, 247-253.Kuang, W., Saraji, S., Piri, M., 2018. A systematic experimental investigation on the synergistic effects of aqueous nanofluids on interfacial properties and their implications for enhanced oil recovery. Fuel 220, 849-870.Pu, W., Zhao, S., Wang, S., Wei, B., Yuan, C., Li, Y., 2018. Investigation into the migration of polymer microspheres (PMs) in porous media: Implications for profile control and oil displacement. Colloids and Surfaces A: Physicochemical and Engineering Aspects 540, 265-275.Sharbatian, A., Abedini, A., Qi, Z., Sinton, D., 2018. Full characterization of CO2–oil properties on-chip: Solubility, diffusivity, extraction pressure, miscibility, and contact angle. Analytical Chemistry 90, 2461-2467.Sivasankar, P., Suresh Kumar, G., 2018. Modelling the influence of interaction between injection and formation brine salinities on in-situ microbial enhanced oil recovery processes by coupling of multiple-ion exchange transport model with multiphase fluid flow and multi-species reactive transport models. Journal of Petroleum Science and Engineering 163, 435-452.Tian, S., Erastova, V., Lu, S., Greenwell, H.C., Underwood, T.R., Xue, H., Zeng, F., Chen, G., Wu, C., Zhao, R., 2018. Understanding model crude oil component interactions on kaolinite silicate and aluminol surfaces: Toward improved understanding of shale oil recovery. Energy & Fuels 32, 1155-1165.Zelenev, A.S., Grenoble, Z., 2018. Wettability of reservoir rocks having different polarity by a model nonionic surfactant: Fluid imbibition study into crushed rock packs. Energy & Fuels 32, 1340-1347.Heavy Oil ProductionLyu, X., Liu, H., Pang, Z., Sun, Z., 2018. Visualized study of thermochemistry assisted steam flooding to improve oil recovery in heavy oil reservoir with glass micromodels. Fuel 218, 118-126.Martínez-Magadán, J.M., Cartas-Rosado, A.R., Oviedo-Roa, R., Cisneros-Dévora, R., Pons-Jiménez, M., Hernández-Altamirano, R., Zamudio-Rivera, L.S., 2018. Molecular design of high performance zwitterionic liquids for enhanced heavy-oil recovery processes. Journal of Molecular Graphics and Modelling 80, 264-271.Pei, H., Shu, Z., Zhang, G., Ge, J., Jiang, P., Qin, Y., Cao, X., 2018. Experimental study of nanoparticle and surfactant stabilized emulsion flooding to enhance heavy oil recovery. Journal of Petroleum Science and Engineering 163, 476-483.Rui, Z., Wang, X., Zhang, Z., Lu, J., Chen, G., Zhou, X., Patil, S., 2018. A realistic and integrated model for evaluating oil sands development with Steam Assisted Gravity Drainage technology in Canada. Applied Energy 213, 76-91.Wang, Z., Gao, D., Fang, J., 2018. Numerical simulation of RF heating heavy oil reservoir based on the coupling between electromagnetic and temperature field. Fuel 220, 14-24.Xu, L., Abedini, A., Qi, Z., Kim, M., Guerrero, A., Sinton, D., 2018. Pore-scale analysis of steam-solvent coinjection: azeotropic temperature, dilution and asphaltene deposition. Fuel 220 151–158.Zhang, Y., Adam, M., Hart, A., Wood, J., Rigby, S.P., Robinson, J.P., 2018. Impact of oil composition on microwave heating behavior of heavy oils. Energy & Fuels 32, 1592-1599.Zhao, Q., Guo, L., Huang, Z., Chen, L., Jin, H., Wang, Y., 2018. Experimental investigation on enhanced oil recovery of extra heavy oil by supercritical water flooding. Energy & Fuels 32, 1685-1692.Recent SedimentsChen, J., Hu, P., Li, X., Yang, Y., Song, J., Li, X., Yuan, H., Li, N., Lü, X., 2018. Impact of water depth on the distribution of iGDGTs in the surface sediments from the northern South China Sea: applicability of TEX86 in marginal seas. Frontiers of Earth Science 12, 95-107.Davtian, N., Bard, E., Ménot, G., Fagault, Y., 2018. The importance of mass accuracy in selected ion monitoring analysis of branched and isoprenoid tetraethers. Organic Geochemistry 118, 58-62.Geilert, S., Hensen, C., Schmidt, M., Liebetrau, V., Scholz, F., Doll, M., Deng, L., Lever, M.A., Su, C.C., Schl?mer, S., Sarkar, S., Thiel, V., Berndt, C., 2018. Transition from hydrothermal vents to cold seeps records timing of carbon release in the Guaymas Basin, Gulf of California. Biogeosciences Discussions 2018, 1-34.Grinham, A., Dunbabin, M., Albert, S., 2018. Importance of sediment organic matter to methane ebullition in a sub-tropical freshwater reservoir. Science of The Total Environment 621, 1199-1207.Li, Z., Lowry, G.V., Fan, J., Liu, F., Chen, J., 2018. High molecular weight components of natural organic matter preferentially adsorb onto nanoscale zero valent iron and magnetite. Science of The Total Environment 628–629, 177-185.Liu, L., De Kock, T., Wilkinson, J., Cnudde, V., Xiao, S., Buchmann, C., Uteau, D., Peth, S., Lorke, A., 2018. Methane bubble growth and migration in aquatic sediments observed by X-ray μCT. Environmental Science & Technology 52, 2007-2015.Makou, M., Eglinton, T., McIntyre, C., Montlu?on, D., Antheaume, I., Grossi, V., 2018. Plant wax n-alkane and n-alkanoic acid signatures overprinted by microbial contributions and old carbon in meromictic lake sediments. Geophysical Research Letters 45, 1049-1057.Sun, D., Tang, J., He, Y., Liao, W., Sun, Y., 2018. Sources, distributions, and burial efficiency of terrigenous organic matter in surface sediments from the Yellow River mouth, northeast China. Organic Geochemistry 118, 89-102.Tishchenko, P.Y., Barabanshchikov, Y.A., Volkova, T.I., Marjash, A.A., Mikhailik, T.A., Pavlova, G.Y., Sagalaev, S.G., Tishchenko, P.P., Khodorenko, N.D., Shkirnikova, E.M., Shvetsova, M.G., 2018. Diagenesis of organic matter in the top layer of the sediments of the Peter the Great Bay in hypoxia locations. Geochemistry International 56, 171-181.Zhou, F., Gao, X., Yuan, H., Song, J., Chen, F., 2018. The distribution and seasonal variations of sedimentary organic matter in the East China Sea shelf. Marine Pollution Bulletin 129, 163-171.Zhuang, G.-C., Heuer, V.B., Lazar, C.S., Goldhammer, T., Wendt, J., Samarkin, V.A., Elvert, M., Teske, A.P., Joye, S.B., Hinrichs, K.-U., 2018. Relative importance of methylotrophic methanogenesis in sediments of the Western Mediterranean Sea. Geochimica et Cosmochimica Acta 224, 171-186.Atmospheric GeochemistryHong, P., Sekine, Y., Sasamori, T., Sugita, S., 2018. Experimental study of heterogeneous organic chemistry induced by far ultraviolet light: Implications for growth of organic aerosols by CH3 addition in the atmospheres of Titan and early Earth. Icarus 307, 25-39.Humphreys, M.P., Daniels, C.J., Wolf-Gladrow, D.A., Tyrrell, T., Achterberg, E.P., 2018. On the influence of marine biogeochemical processes over CO2 exchange between the atmosphere and ocean. Marine Chemistry 199, 1-11.Hydrosphere GeochemistryAl-Said, T., Naqvi, S.W.A., Al-Yamani, F., Goncharov, A., Fernandes, L., 2018. High total organic carbon in surface waters of the northern Arabian Gulf: Implications for the oxygen minimum zone of the Arabian Sea. Marine Pollution Bulletin 129, 35-42.Albéric, P., Pérez, M.A.P., Moreira-Turcq, P., Benedetti, M.F., Bouillon, S., Abril, G., 2018. Variation of the isotopic composition of dissolved organic carbon during the runoff cycle in the Amazon River and the floodplains. Comptes Rendus Geoscience 350, 65-75.Balch, W.M., Bowler, B.C., Drapeau, D.T., Lubelczyk, L.C., Lyczkowski, E., 2018. Vertical distributions of coccolithophores, PIC, POC, biogenic silica, and chlorophyll a throughout the global ocean. Global Biogeochemical Cycles 32, 2-17.Barnes, R.T., Butman, D.E., Wilson, H.F., Raymond, P.A., 2018. Riverine export of aged carbon driven by flow path depth and residence time. Environmental Science & Technology 52, 1028-1035.Belt, S.T., Brown, T.A., Smik, L., Assmy, P., Mundy, C.J., 2018. Sterol identification in floating Arctic sea ice algal aggregates and the Antarctic sea ice diatom Berkeleya adeliensis. Organic Geochemistry 118, 1-3.Bercovici, S.K., McNichol, A.P., Xu, L., Hansell, D.A., 2018. Radiocarbon content of dissolved organic carbon in the South Indian Ocean. Geophysical Research Letters 45, 872-879.Cao, X., Aiken, G.R., Butler, K.D., Mao, J., Schmidt-Rohr, K., 2018. Comparison of the chemical composition of dissolved organic matter in three lakes in Minnesota. Environmental Science & Technology 52, 1747-1755.Chance, R.J., Hamilton, J.F., Carpenter, L.J., Hackenberg, S.C., Andrews, S.J., Wilson, T.W., 2018. Water-soluble organic composition of the Arctic Sea surface microlayer and association with ice nucleation ability. Environmental Science & Technology 52, 1817-1826.Coward, E.K., Ohno, T., Plante, A.F., 2018. Adsorption and molecular fractionation of dissolved organic matter on iron-bearing mineral matrices of varying crystallinity. Environmental Science & Technology 52, 1036-1044.Hu, Z., Kang, S., Yan, F., Zhang, Y., Li, Y., Chen, P., Qin, X., Wang, K., Gao, S., Li, C., 2018. Dissolved organic carbon fractionation accelerates glacier-melting: A case study in the northern Tibetan Plateau. Science of The Total Environment 627, 579-585.Jeanneau, L., Rowland, R., Inamdar, S., 2018. Molecular fingerprinting of particulate organic matter as a?new tool for its source apportionment: changes along a?headwater drainage in coarse, medium and fine particles as a?function of rainfalls. Biogeosciences 15, 973-985.Kanapatskiy, T.A., Samylina, O.S., Plotnikov, A.O., Selivanova, E.A., Khlopko, Y.A., Kuznetsova, A.I., Rusanov, I.I., Zakharova, E.E., Pimenov, N.V., 2018. Microbial processes of organic matter production and decomposition in saline rivers of the Lake Elton area (Volgograd oblast, Russia). Microbiology 87, 66-78.Lee, S.A., Kim, G., 2018. Sources, fluxes, and behaviors of fluorescent dissolved organic matter (FDOM) in the Nakdong River Estuary, Korea. Biogeosciences 15, 1115-1122.Lovecchio, E., Gruber, N., Münnich, M., 2018. Mesoscale contribution to the long-range offshore transport of organic carbon from the Canary Upwelling System to the open North Atlantic. Biogeosciences Discussions 2018, 1-47.Mari, X., Passow, U., Migon, C., Burd, A.B., Legendre, L., 2017. Transparent exopolymer particles: Effects on carbon cycling in the ocean. Progress in Oceanography 151, 13-37.McCrimmon, D.O., Bizimis, M., Holland, A., Ziolkowski, L.A., 2018. Supraglacial microbes use young carbon and not aged cryoconite carbon. Organic Geochemistry 118, 63-72.Morée, A.L., Schwinger, J., Heinze, C., 2018. Southern Ocean controls of the vertical marine δ13C gradient – a modelling study. Biogeosciences Discussions 2018, 1-24.Patriarca, C., Bergquist, J., Sj?berg, P.J.R., Tranvik, L., Hawkes, J.A., 2018. Online HPLC-ESI-HRMS method for the analysis and comparison of different dissolved organic matter samples. Environmental Science & Technology 52, 2091-2099.Pokrovsky, O.S., Karlsson, J., Giesler, R., 2018. Freeze-thaw cycles of Arctic thaw ponds remove colloidal metals and generate low-molecular-weight organic matter. Biogeochemistry 137, 321-336.Retelletti Brogi, S., Ha, S.-Y., Kim, K., Derrien, M., Lee, Y.K., Hur, J., 2018. Optical and molecular characterization of dissolved organic matter (DOM) in the Arctic ice core and the underlying seawater (Cambridge Bay, Canada): Implication for increased autochthonous DOM during ice melting. Science of The Total Environment 627, 802-811.Sargeant, S.L., Murrell, J.C., Nightingale, P.D., Dixon, J.L., 2018. Basin-scale variability of microbial methanol uptake in the Atlantic Ocean. Biogeosciences Discussions 2018, 1-28.Shen, Y., Benner, R., 2018. Mixing it up in the ocean carbon cycle and the removal of refractory dissolved organic carbon. Scientific Reports 8, Article 2542.Stanev, E.V., Poulain, P.-M., Grayek, S., Johnson, K.S., Claustre, H., Murray, J.W., 2018. Understanding the dynamics of the oxic-anoxic interface in the Black Sea. Geophysical Research Letters 45, 864-871.Stuckey, J.W., Goodwin, C., Wang, J., Kaplan, L.A., Vidal-Esquivel, P., Beebe, T.P., Sparks, D.L., 2018. Impacts of hydrous manganese oxide on the retention and lability of dissolved organic matter. Geochemical Transactions 19, Article 6.Wang, J.-J., Lafrenière, M.J., Lamoureux, S.F., Simpson, A.J., Gélinas, Y., Simpson, M.J., 2018. Differences in riverine and pond water dissolved organic matter composition and sources in Canadian high arctic watersheds affected by active layer detachments. Environmental Science & Technology 52, 1062-1071.Zhou, Z., Zhou, M., Yang, X., Niu, J., Meng, F., 2018. Sunlight irradiation triggers changes in the fouling potentials of natural dissolved organic matter. Science of The Total Environment 627, 227-234.Soil GeochemistryAlbers, C.N., Kramsh?j, M., Rinnan, R., 2018. Rapid mineralization of biogenic volatile organic compounds in temperate and Arctic soils. Biogeosciences Discussions 2018, 1-18.Beňo, E., Góra, R., Hutta, M., 2018. Development of a precolumn derivatization HPLC method with diode-array detection for the determination of amino sugars in peat and soil humic acids. Journal of Separation Science 41, 814-821.Chang, Z., Tian, L., Li, F., Zhou, Y., Wu, M., Steinberg, C.E.W., Dong, X., Pan, B., Xing, B., 2018. Benzene polycarboxylic acid — A useful marker for condensed organic matter, but not for only pyrogenic black carbon. Science of The Total Environment 626, 660-667.Dai, G., Ma, T., Zhu, S., Liu, Z., Chen, D., Bai, Y., Chen, L., He, J.-S., Zhu, J., Zhang, Y., Lü, X., Wang, X., Han, X., Feng, X., 2018. Large-scale distribution of molecular components in Chinese grassland soils: The influence of input and decomposition processes. Journal of Geophysical Research: Biogeosciences 123, 239-255.Escobar-Arnanz, J., Mekni, S., Blanco, G., Eljarrat, E., Barceló, D., Ramos, L., 2018. Characterization of organic aromatic compounds in soils affected by an uncontrolled tire landfill fire through the use of comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry. Journal of Chromatography A 1536, 163-175.Jung, P., Briegel-Williams, L., Simon, A., Thyssen, A., Büdel, B., 2018. Uncovering biological soil crusts: carbon content and structure of intact Arctic, Antarctic and alpine biological soil crusts. Biogeosciences 15, 1149-1160.Li, X.-M., Sun, G.-X., Chen, S.-C., Fang, Z., Yuan, H.-Y., Shi, Q., Zhu, Y.-G., 2018. Molecular chemodiversity of dissolved organic matter in paddy soils. Environmental Science & Technology 52, 963-971.Prost, K., Bradel, P.L., Lehndorff, E., Amelung, W., 2018. Steroid dissipation and formation in the course of farmyard manure composting. Organic Geochemistry 118, 47-57.Wang, C., Houlton, B.Z., Liu, D., Hou, J., Cheng, W., Bai, E., 2018. Stable isotopic constraints on global soil organic carbon turnover. Biogeosciences 15, 987-995.Zheng, J., Thornton, P.E., Painter, S.L., Gu, B., Wullschleger, S.D., Graham, D.E., 2018. Modeling anaerobic soil organic carbon decomposition in Arctic polygon tundra: insights into soil geochemical influences on carbon mineralization. Biogeosciences Discussions 2018, 1-31.Remote Sensing-Hydrocarbon SeepageCarvalho, L., Monteiro, R., Figueira, P., Mieiro, C., Almeida, J., Pereira, E., Magalh?es, V., Pinheiro, L., Vale, C., 2018. Vertical distribution of major, minor and trace elements in sediments from mud volcanoes of the Gulf of Cadiz: evidence of Cd, As and Ba fronts in upper layers. Deep Sea Research Part I: Oceanographic Research Papers 131, 133-143.Daskalopoulou, K., Calabrese, S., Grassa, F., Kyriakopoulos, K., Parello, F., Tassi, F., D'Alessandro, W., 2018. Origin of methane and light hydrocarbons in natural fluid emissions: A key study from Greece. Chemical Geology 479, 286-301.Dill, H.G., Kaufhold, S., 2018. The Totumo mud volcano and its near-shore marine sedimentological setting (North Colombia) — From sedimentary volcanism to epithermal mineralization. Sedimentary Geology 366, 14-31.Krajewski, L.C., Lobodin, V.V., Johansen, C., Bartges, T.E., Maksimova, E.V., MacDonald, I.R., Marshall, A.G., 2018. Linking natural oil seeps from the Gulf of Mexico to their origin by use of Fourier transform ion cyclotron resonance mass spectrometry. Environmental Science & Technology 52, 1365-1374.Source Rocks/Depositional EnvironmentsAbarghani, A., Ostadhassan, M., Gentzis, T., Carvajal-Ortiz, H., Bubach, B., 2018. Organofacies study of the Bakken source rock in North Dakota, USA, based on organic petrology and geochemistry. International Journal of Coal Geology 188, 79-93.Adeniyi, E.O., Ossa Ossa, F., Kramers, J.D., de Kock, M.O., Belyanin, G., Beukes, N.J., 2018. Cause and timing of the thermal over-maturation of hydrocarbon source rocks of the Ecca Group (Main Karoo Basin, South Africa). Marine and Petroleum Geology 91, 480-500.Bai, C., Yu, B., Liu, H., Xie, Z., Han, S., Zhang, L., Ye, R., Ge, J., 2018. The genesis and evolution of carbonate minerals in shale oil formations from Dongying depression, Bohai Bay Basin, China. International Journal of Coal Geology 189, 8-26.Brodie, M.W., Aplin, A.C., Hart, B., Orland, I.J., Valley, J.W., Boyce, A.J., 2018. Oxygen isotope microanalysis by secondary ion mass spectrometry suggests continuous 300-million-year history of calcite cementation and dolomitization in the Devonian Bakken Formation. Journal of Sedimentary Research 88, 91-104.Burnham, A.K., 2018. Thermomechanical properties of the Garden Gulch Member of the Green River Formation. Fuel 219, 477-491.Cao, J., Yang, R., Yin, W., Hu, G., Bian, L., Fu, X., 2018. Mechanism of organic matter accumulation in residual bay environments: The Early Cretaceous Qiangtang Basin, Tibet. Energy & Fuels 32, 1024-1037.Chen, G., Gang, W.Z., Wang, N., Zhao, L.Y., 2018. Geochemical characterisation of the Xiagou Formation carbonate-bearing mudstone in southwestern Jiuquan Basin, China: implications for paleo-environment reconstruction and the origin of organic matter. Australian Journal of Earth Sciences 65, 121-134.Coward, A.J., Mays, C., Patti, A.F., Stilwell, J.D., O'Dell, L.A., Viegas, P., 2018. Taphonomy and chemotaxonomy of Eocene amber from southeastern Australia. Organic Geochemistry 118, 103-115.Fonseca, C., Mendon?a, J.O., Mendon?a Filho, J.G., Lézin, C., Duarte, L.V., 2018. Thermal maturity assessment study of the late Pliensbachian-early Toarcian organic-rich sediments in southern France: Grands Causses, Quercy and Pyrenean basins. Marine and Petroleum Geology 91, 338-349.Gao, G., Zhang, G., Chen, G., Gang, W., Shen, H., Zhao, K., 2018. Geochemistry of borehole cutting shale and natural gas accumulation in the deepwater area of the Zhujiang River Mouth-Qiongdongnan Basin in the northern South China Sea. Acta Oceanologica Sinica 37, 44-53.Hao, Z., Bechtel, H.A., Kneafsey, T., Gilbert, B., Nico, P.S., 2018. Cross-scale molecular analysis of chemical heterogeneity in shale rocks. Scientific Reports 8, Article 2552.Hu, T., Pang, X., Jiang, S., Wang, Q., Zheng, X., Ding, X., Zhao, Y., Zhu, C., Li, H., 2018. Oil content evaluation of lacustrine organic-rich shale with strong heterogeneity: A case study of the Middle Permian Lucaogou Formation in Jimusaer Sag, Junggar Basin, NW China. Fuel 221, 196-205.Hudspith, V.A., Hadden, R.M., Bartlett, A.I., Belcher, C.M., 2018. Does fuel type influence the amount of charcoal produced in wildfires? Implications for the fossil record. Palaeontology 61, 159-171.Jackson, T.A., 2018. Variations in the properties of extractable “humic matter” and associated kerogen in sediments through geologic time: Their significance for Precambrian biological evolution and paleoecology. Geomicrobiology Journal 35, 334-353.Lai, H., Li, M., Liu, J., Mao, F., Xiao, H., He, W., Yang, L., 2018. Organic geochemical characteristics and depositional models of Upper Cretaceous marine source rocks in the Termit Basin, Niger. Palaeogeography, Palaeoclimatology, Palaeoecology 495, 292-308.Lash, G.G., 2018. Significance of stable carbon isotope trends in carbonate concretions formed in association with anaerobic oxidation of methane (AOM), Middle and Upper Devonian shale succession, western New York State, USA. Marine and Petroleum Geology 91, 470-479.Liu, H., Ren, J., Lyu, J., Lyu, X., Feng, Y., 2018. Hydrocarbon source rock evaluation of the Lower Cretaceous system in the Baibei Depression, Erlian Basin. Energy Exploration & Exploitation 36, 355-372.Radhwani, M., Bechtel, A., Singh, V.P., Singh, B.D., Manna?-Tayech, B., 2018. Petrographic, palynofacies and geochemical characteristics of organic matter in the Saouef Formation (NE Tunisia): Origin, paleoenvironment, and economic significance. International Journal of Coal Geology 187, 114-130.Radlinski, A.P., Mastalerz, M., 2018. Neutron scattering study of vitrinite: Insights into sub-micrometer inclusions in North American Carboniferous coals of bituminous rank. International Journal of Coal Geology 186, 145-154.Schmidt, A.R., Kaulfuss, U., Bannister, J.M., Baranov, V., Beimforde, C., Bleile, N., Borkent, A., Busch, A., Conran, J.G., Engel, M.S., Harvey, M., Kennedy, E.M., Kerr, P.H., Kettunen, E., Kiecksee, A.P., Lengeling, F., Lindqvist, J.K., Maraun, M., Mildenhall, D.C., Perrichot, V., Rikkinen, J., Sadowski, E.-M., Seyfullah, L.J., Stebner, F., Szwedo, J., Ulbrich, P., Lee, D.E., 2018. Amber inclusions from New Zealand. Gondwana Research 56, 135-146.Spacapan, J.B., Palma, J.O., Galland, O., Manceda, R., Rocha, E., D'Odorico, A., Leanza, H.A., 2018. Thermal impact of igneous sill-complexes on organic-rich formations and implications for petroleum systems: A case study in the northern Neuquén Basin, Argentina. Marine and Petroleum Geology 91, 519-531.Spina, A., Vecoli, M., Riboulleau, A., Clayton, G., Cirilli, S., Di Michele, A., Marcogiuseppe, A., Rettori, R., Sassi, P., Servais, T., Riquier, L., 2018. Application of Palynomorph Darkness Index (PDI) to assess the thermal maturity of palynomorphs: A case study from North Africa. International Journal of Coal Geology 188, 64-78.Tarhan, L.G., 2018. The early Paleozoic development of bioturbation—Evolutionary and geobiological consequences. Earth-Science Reviews 178, 177-207.Wang, X., He, S., Guo, X., Zhang, B., Chen, X., 2018. The resource evaluation of Jurassic shale in North Fuling area, eastern Sichuan Basin, China. Energy & Fuels 32, 1213-1222.Wilkins, R.W.T., Sherwood, N., Li, Z., 2018. RaMM (Raman maturity method) study of samples used in an interlaboratory exercise on a standard test method for determination of vitrinite reflectance on dispersed organic matter in rocks. Marine and Petroleum Geology 91, 236-250.Wu, X., Chen, Y., Zhao, G., Du, X., Zeng, H., Wang, P., Wang, Y., Hu, Y., 2017. Evaluation of source rocks in the 5th member of the Upper Triassic Xujiahe Formation in the Xinchang Gas Field, the Western Sichuan Depression, China. Journal of Natural Gas Geoscience 2, 253-262.Yin, J., Wang, Q., Hao, F., Guo, L., Zou, H., 2018. Palaeoenvironmental reconstruction of lacustrine source rocks in the lower 1st Member of the Shahejie Formation in the Raoyang Sag and the Baxian Sag, Bohai Bay Basin, eastern China. Palaeogeography, Palaeoclimatology, Palaeoecology 495, 87-104.Zhang, K., Jin, W., Lin, H., Dong, C., Wu, S., 2018. Major and trace elemental compositions of the upper Carboniferous Batamayineishan mudrocks, Wulungu area, Junggar Basin, China: Implications for controls on the formation of the organic-rich source rocks. Marine and Petroleum Geology 91, 550-561.Zhang, M., Fu, X., 2018. Study of the characteristics of marine–terrigenous facies shale from the Permo-Carboniferous system in the Guxian Block, southwest Qinshui Basin. Energy & Fuels 32, 1096-1109.Ziyong, Z., Hangyu, Y., Xiaodan, G., 2018. Fuzzy fusion of geological and geophysical data for mapping hydrocarbon potential based on GIS. Petroleum Geoscience 24, 131-141.Unconventional ResourcesAbdulelah, H., Mahmood, S.M., Al-Mutarreb, A., 2018. Effect of anionic surfactant on wettability of shale and its implication on gas adsorption/desorption behavior. Energy & Fuels 32, 1423-1432.Alharthy, N., Teklu, T.W., Kazemi, H., Graves, R.M., Hawthorne, S.B., Braunberger, J., Kurtoglu, B., 2018. Enhanced oil recovery in liquid-rich shale reservoirs: Laboratory to field, SPE-175034-PA. SPE Reservoir Evaluation and Engineering 21, 137-159.Bakshi, T., Prusty, B.K., Pathak, K., Pal, S.K., 2018. Pore characteristics of Damodar Valley shale and their effect on gas storage potential. Journal of Petroleum Science and Engineering 162, 725-735.Dachanuwattana, S., Jin, J., Zuloaga-Molero, P., Li, X., Xu, Y., Sepehrnoori, K., Yu, W., Miao, J., 2018. Application of proxy-based MCMC and EDFM to history match a Vaca Muerta shale oil well. Fuel 220, 490-502.Dang, W., Zhang, J.-C., Tang, X., Wei, X.-L., Li, Z.-M., Wang, C.-H., Chen, Q., Liu, C., 2018. Investigation of gas content of organic-rich shale: A case study from Lower Permian shale in southern North China Basin, central China. Geoscience Frontiers 9, 559-575.Davudov, D., Moghanloo, R.G., 2018. Impact of pore compressibility and connectivity loss on shale permeability. International Journal of Coal Geology 187, 98-113.Guo, H., He, R., Jia, W., Peng, P.a., Lei, Y., Luo, X., Wang, X., Zhang, L., Jiang, C., 2018. Pore characteristics of lacustrine shale within the oil window in the Upper Triassic Yanchang Formation, southeastern Ordos Basin, China. Marine and Petroleum Geology 91, 279-296.Gupta, N., Fathi, E., Belyadi, F., 2018. Effects of nano-pore wall confinements on rarefied gas dynamics in organic rich shale reservoirs. Fuel 220, 120-129.Hazra, B., Wood, D.A., Vishal, V., Varma, A.K., Sakha, D., Singh, A.K., 2018. Porosity controls and fractal disposition of organic-rich Permian shales using low-pressure adsorption techniques. Fuel 220, 837-848.Ho, T.A., Wang, Y., Xiong, Y., Criscenti, L.J., 2018. Differential retention and release of CO2 and CH4 in kerogen nanopores: Implications for gas extraction and carbon sequestration. Fuel 220, 1-7.Hou, H., Shao, L., Li, Y., Li, Z., Zhang, W., Wen, H., 2018. The pore structure and fractal characteristics of shales with low thermal maturity from the Yuqia Coalfield, northern Qaidam Basin, northwestern China. Frontiers of Earth Science 12, 148-159.Hu, H., Hao, F., Guo, X., Dai, F., Lu, Y., Ma, Y., 2018. Investigation of methane sorption of overmature Wufeng-Longmaxi shale in the Jiaoshiba area, Eastern Sichuan Basin, China. Marine and Petroleum Geology 91, 251-261.Hu, T., Pang, X., Jiang, S., Wang, Q., Zheng, X., Ding, X., Zhao, Y., Zhu, C., Li, H., 2018. Oil content evaluation of lacustrine organic-rich shale with strong heterogeneity: A case study of the Middle Permian Lucaogou Formation in Jimusaer Sag, Junggar Basin, NW China. Fuel 221, 196-205.Liao, D., Lu, B., 2018. An evaluation method of engineering sweet spots of shale gas reservoir development: A case study from the Jiaoshiba Gas Field, Sichuan Basin. Natural Gas Industry 38, 43-50.Liu, S., Wang, Z., Zhang, L., 2018. Experimental study on the cracking process of layered shale using X-ray microCT. Energy Exploration & Exploitation 36, 297-313.Liu, Y., Wang, C., 2018. Determination of the absolute adsorption isotherms of CH4 on shale with low-field nuclear magnetic resonance. Energy & Fuels 32, 1406-1415.Lyu, C., Ning, Z., Wang, Q., Chen, M., 2018. Application of NMR T2 to pore size distribution and movable fluid distribution in tight sandstones. Energy & Fuels 32, 1395-1405.Mendhe, V.A., Mishra, S., Varma, A.K., Kamble, A.D., Bannerjee, M., Singh, B.D., Sutay, T.M., Singh, V.P., 2018. Geochemical and petrophysical characteristics of Permian shale gas reservoirs of Raniganj Basin, West Bengal, India. International Journal of Coal Geology 188, 1-24.Meng, Q., Wang, X., Wang, X., Lei, Y., Liu, P., Zhang, L., Jiang, C., Gao, C., 2018. Biodegradation of light hydrocarbon (C5-C8) in shale gases from the Triassic Yanchang Formation, Ordos basin, China. Journal of Natural Gas Science and Engineering 51, 183-194.Morga, R., Pawlyta, M., 2018. Microstructure of graptolite periderm in Silurian gas shales of Northern Poland. International Journal of Coal Geology 189, 1-7.Pan, B., Li, Y., Wang, H., Jones, F., Iglauer, S., 2018. CO2 and CH4 wettabilities of organic-rich shale. Energy & Fuels 32, 1914-1922.Pan, Y., Hui, D., Luo, P., Zhang, Y., Sun, L., Wang, K., 2018. Experimental investigation of the geochemical interactions between supercritical CO2 and shale: Implications for CO2 storage in gas-bearing shale formations. Energy & Fuels 32, 1963-1978.Pang, Y., Soliman, M.Y., Sheng, J., 2018. Investigating gas-adsorption, stress-dependence, and non-Darcy-flow effects on gas storage and transfer in nanopores by use of simplified local density model. SPE Reservoir Evaluation and Engineering 21, 73-95.Santos, M.S., Franco, L.F.M., Castier, M., Economou, I.G., 2018. Molecular dynamics simulation of n-alkanes and CO2 confined by calcite nanopores. Energy & Fuels 32, 1934-1941.Singer, P.M., Chen, Z., Alemany, L.B., Hirasaki, G.J., Zhu, K., Xie, Z.H., Vo, T.D., 2018. Interpretation of NMR relaxation in bitumen and organic shale using polymer–heptane mixes. Energy & Fuels 32, 1534-1549.Tathed, P., Han, Y., Misra, S., 2018. Hydrocarbon saturation in upper Wolfcamp shale formation. Fuel 219, 375-388.Wang, B., Qin, Y., Shen, J., Zhang, Q., Wang, G., 2018. Pore structure characteristics of low- and medium-rank coals and their differential adsorption and desorption effects. Journal of Petroleum Science and Engineering 165, 1-12.Wu, W., Shi, X., Liu, J., Li, D., Xie, J., Zhao, S., Ji, C., Hu, Y., Guo, Y., 2017. Accumulation conditions and exploration potential of Wufeng-Longmaxi Formations shale gas in Wuxi area, Northeastern Sichuan Basin, China. Journal of Natural Gas Geoscience 2, 263-271.Yang, S., Chen, G., Lv, C., Li, C., Yin, N., Yang, F., Xue, L., 2018. Evolution of nanopore structure in lacustrine organic-rich shales during thermal maturation from hydrous pyrolysis, Minhe Basin, Northwest China. Energy Exploration & Exploitation 36, 265-281.Yoon, S.H., Joe, Y.J., Koh, C.S., Woo, J.H., Lee, H.S., 2018. Sedimentary processes and depositional environments of the gas-bearing Horn River shale in British Columbia, Canada. Geosciences Journal 22, 33-46.Zeng, F., Guo, J., Ma, S., Chen, Z., 2018. 3D observations of the hydraulic fracturing process for a model non-cemented horizontal well under true triaxial conditions using an X-ray CT imaging technique. Journal of Natural Gas Science and Engineering 52, 128-140.Zhu, C., Li, Y., Gong, H., Sang, Q., Li, Z., Dong, M., 2018. Adsorption and dissolution behaviors of carbon dioxide and n-dodecane mixtures in shale. Energy & Fuels 32, 1374-1386.AbstractsAbarghani, A., Ostadhassan, M., Gentzis, T., Carvajal-Ortiz, H., Bubach, B., 2018. Organofacies study of the Bakken source rock in North Dakota, USA, based on organic petrology and geochemistry. International Journal of Coal Geology 188, 79-93. taken from the Upper and Lower members of the Bakken Formation in four wells that were drilled in a northeast - southwest trend along the eastern margin of the Williston Basin in central-western North Dakota were investigated in order to present an overview of source-rock quality and depositional environment conditions for the main purpose of establishing an organofacies model. Several techniques such as Rock-Eval 6 pyrolysis, X-Ray fluorescence elemental analysis, vitrinite reflectance, organic petrography and visual kerogen assessment using reflected and transmitted white light and UV light microscopy on whole-rock pellets were combined to draw the best possible conclusions. The results indicate that kerogen is mainly marine type II with increasing in maturity towards the central and SW portions of the basin. Detailed organic petrography of the samples showed that solid bitumen, amorphous matrix bituminite, granular bitumen, alginite, acritarchs, and liptodetrinite are the most abundant macerals. In order to properly determine the Bakken organofacies, the original hydrogen index (HIo) was restored using various mathematical models and empirical methods. The mathematically restored HIo from thermally mature samples (HIo-Calculated) was then compared to the HI values from thermally immature samples (Tmax?<?430?°C, here interpreted as HIo) for further verification. Although the agreement between the Rock-Eval pyrolysis HIo and the HIo-Calculated by the two mathematical equations was excellent, the VKA-derived HIo values were underestimated by about 125?mg?HC/g TOC. In the next step, the above parameters were integrated to identify the organofacies based on three different models. It was found that organofacies B is the most abundant organofacies present in the Bakken source rock. Furthermore, elemental analysis reflected a high concentration of “strong euxinic affinity” trace elements such as Mo, V, and Zn, representing an anoxic/euxinic depositional environment condition for the Bakken Shale.Abdulelah, H., Mahmood, S.M., Al-Mutarreb, A., 2018. Effect of anionic surfactant on wettability of shale and its implication on gas adsorption/desorption behavior. Energy & Fuels 32, 1423-1432. the fracking process in shale, an interaction occurs between shale and fracking fluid that contains a cocktail of chemicals. One of the chemicals used in fracking fluid is often surfactant, which is generally used as a viscofier. However, surfactants also have the potential of significantly influencing the wettability and thus gas desorption–key factors affecting ultimate gas recovery from shale reservoirs. Even though a few studies discussed the ability of surfactants to alter wettability in shale, the implication of that change in adsorption/desorption behavior has never been experimentally investigated beyond hypothetical inferences. In this study, the influence of the wettability change by anionic surfactant on gas adsorption/desorption behavior in shale was investigated through a series of experiments. Baseline wettability readings of two shale samples were established by measuring the contact angles (BG-1 = 22.7°, KH-1 = 35°) between a drop of pure water placed on their polished surfaces, indicating that the affinity of pure water for the BG-1 surface was greater than that for KH-1. This difference can be attributed to the higher clay content and lower total organic carbon found in BG-1 as compared to KH-1. To investigate the impact of the interaction between shale and surfactants on wettability during the fracking process, we measured the contact angles again, this time with 1 wt % solution of internal olefin sulfate surfactant. The surfactant-induced wettability changes of the two shale samples were investigated by measuring the contact angles again (BG-1 = 3.5°, KH-1 = 19.2°) between a drop of surfactant solution and their polished surfaces. The effect of wettability changes on gas adsorption/desorption was then evaluated utilizing the United States bureau of mines’ modified method. Experiments were conducted on the two shale samples in two ways: after pure water treatment, and after surfactant treatment. The results suggest that due to the wettability alteration of the two shale samples by IOS surfactant toward more water-wet during the treatment, the methane adsorption/desorption characteristics were influenced. In BG-1 sample, IOS solution dramatically changed its wettability to become completely water-wet. Therefore, the volume of desorbed methane dropped by nearly 54%. A similar but less pronounced influence was found in the KH-1 sample, where its desorbed methane dropped by 10% because of wettability alteration toward more water-wet. These reductions in the amount of desorbed gas suggest that prior to selecting a surfactant for addition to fracking fluid, its effect on wettability and gas desorption should be investigated to optimize shale gas recovery potential.Adam, P.S., Borrel, G., Gribaldo, S., 2018. Evolutionary history of carbon monoxide dehydrogenase/acetyl-CoA synthase, one of the oldest enzymatic complexes. Proceedings of the National Academy of Sciences 115, E1166-E1173.: Before the emergence of oxygenic photosynthesis and the accumulation of oxygen on Earth, life was essentially composed of anaerobic microorganisms. However, very little is known about which metabolisms were present at the time. Anaerobic carbon fixation through the Wood–Ljungdahl pathway is believed to be among the most ancient, and still plays a pivotal role in modern ecosystems. However, its origin and evolutionary history has been disputed. We analysed the distribution and phylogeny of carbon monoxide dehydrogenase/acetyl-CoA synthase, the main enzymatic complex of the pathway in thousands of bacterial and archaeal genomes. We show that this complex was already at work in the last universal common ancestor and has been remarkably conserved in microorganisms over more than 3.5 billion years. Abstract: Carbon monoxide dehydrogenase/acetyl-CoA synthase (CODH/ACS) is a five-subunit enzyme complex responsible for the carbonyl branch of the Wood–Ljungdahl (WL) pathway, considered one of the most ancient metabolisms for anaerobic carbon fixation, but its origin and evolutionary history have been unclear. While traditionally associated with methanogens and acetogens, the presence of CODH/ACS homologs has been reported in a large number of uncultured anaerobic lineages. Here, we have carried out an exhaustive phylogenomic study of CODH/ACS in over 6,400 archaeal and bacterial genomes. The identification of complete and likely functional CODH/ACS complexes in these genomes significantly expands its distribution in microbial lineages. The CODH/ACS complex displays astounding conservation and vertical inheritance over geological times. Rare intradomain and interdomain transfer events might tie into important functional transitions, including the acquisition of CODH/ACS in some archaeal methanogens not known to fix carbon, the tinkering of the complex in a clade of model bacterial acetogens, or emergence of archaeal–bacterial hybrid complexes. Once these transfers were clearly identified, our results allowed us to infer the presence of a CODH/ACS complex with at least four subunits in the last universal common ancestor (LUCA). Different scenarios on the possible role of ancestral CODH/ACS are discussed. Despite common assumptions, all are equally compatible with an autotrophic, mixotrophic, or heterotrophic LUCA. Functional characterization of CODH/ACS from a larger spectrum of bacterial and archaeal lineages and detailed evolutionary analysis of the WL methyl branch will help resolve this issue. Adeniyi, E.O., Ossa Ossa, F., Kramers, J.D., de Kock, M.O., Belyanin, G., Beukes, N.J., 2018. Cause and timing of the thermal over-maturation of hydrocarbon source rocks of the Ecca Group (Main Karoo Basin, South Africa). Marine and Petroleum Geology 91, 480-500. source rocks of the Main Karoo Basin, South Africa are believed to have undergone thermal over-maturation close to the Jurassic-aged Karoo Large Igneous Province (KLIP) dolerite intrusions. Yet, the cause and timing of this source rock exhaustion event likely to have extensively destroyed their shale gas potential remain controversial. Based on drill core samples from the central Main Karoo Basin, we investigated the clay mineralogy of the 2:1:1 and 2:1 phyllosilicate groups, and have carried out 40Ar/39Ar radiometric dating of illite. The X-ray diffractograms (XRD) and mineral chemistry reveal that chlorite and illite phases of samples close to the dolerite intrusions are characterized by higher crystallinity with a chemical composition indicative of formation in a metamorphic environment. In contrast, chlorite and illite distal to any dolerite intrusion show lower crystal growth rates with chemical compositions suggesting formation in a diagenetic environment. 40Ar/39Ar radiometric dating indicates that illite in samples distal to the dolerite intrusions formed between 292 and 245 Ma with some ages clustering around 281 Ma. The oldest ages are consistent with a detrital fraction probably recycled from the erosion of the ash bed at the top of the underlying Dwyka Group. However, ages around 281 Ma can be linked with estimated depositional age of the Ecca Group at ～280 Ma, while the youngest ages may reflect late diagenesis to regional metamorphism. Illite fractions from samples close to dolerite shows formation age between 204 and 170 Ma, consistent with the time of the KLIP dolerite sills and dykes intrusions at ～180 Ma. This illustrates that the ages of these illites were partially or totally re-set due to recrystallization in a late thermal anomaly induced by the intrusion of dolerites. The correlation between the timing of the youngest mineral transformation processes and the KLIP represents strong evidence suggesting that source rocks of the Ecca Group experienced a thermal overprinting event ～180 Ma ago. This late thermal anomaly is consistent with previous data illustrating thermal over-maturation and metamorphic devolatilization of Ecca Group shales situated close to the dolerite intrusions.Aderhold, D.G.R., Lindeberg, M.R., Holderied, K., Pegau, S.W., 2018. Spatial and temporal ecological variability in the northern Gulf of Alaska: What have we learned since the Exxon Valdez oil spill? Deep Sea Research Part II: Topical Studies in Oceanography 147, 3-8. special issue examines oceanographic and biological variability in the northern Gulf of Alaska region with an emphasis on recent monitoring efforts of the Gulf Watch Alaska (GWA) and Herring Research and Monitoring (HRM) programs funded by the Exxon Valdez Oil Spill Trustee Council (EVOSTC). These programs are designed to improve our understanding of how changing environmental conditions affect Gulf of Alaska ecosystems and the long-term status of resources injured by the Exxon Valdez oil spill.The northern Gulf of Alaska shelf and large estuaries of Prince William Sound and Cook Inlet form a productive, dynamic marine region that supports numerous fish, shellfish, bird, and mammal populations. Pelagic and nearshore ecosystems in this region are subject to large-scale variability from both natural and anthropogenic sources. Oceanographic and meteorological conditions across the region vary on seasonal, interannual, and decadal time scales in response to different modes of climate variation in the North Pacific, including El Ni?o/La Ni?a events (Weingartner et al., 2002), the Pacific Decadal Oscillation (Mantua et al., 1997), and the North Pacific Gyre Oscillation (Di Lorenzo et al., 2008). Recently, the 2014–2016 Pacific marine heat wave caused unprecedented warming in the northern Gulf of Alaska and ecological changes associated with this event are being assessed (Bond et al., 2015; Di Lorenzo and Mantua, 2016 ; Walsh et al., In press). Some climate variations have driven biological “regime shifts” during which species assemblages have changed quickly and drastically across the Gulf of Alaska region. A well-documented regime shift occurred in 1976/1977 when there was a transition from shellfish to fish-dominated fisheries in Alaskan waters associated with a shift from a negative to positive phase of the Pacific Decadal Oscillation and warming in the Gulf of Alaska (Anderson and Piatt, 1999). Additional climate-driven biological changes in the North Pacific have been inferred from climatological and biological datasets (Batten and Welch, 2004 ; Hare and Mantua, 2000). Future changes in ocean temperature, ocean acidification, freshwater inputs, and sea level rise associated with climate variations and long-term change will continue to affect pelagic and nearshore ecosystems in the northern Gulf of Alaska shelf.Anthropogenic effects in the northern Gulf of Alaska include marine harvest practices such as large biomass removals, hatchery-enhanced salmon fisheries, point and non-point sources of pollution, and the Exxon Valdez oil spill. The oil tanker Exxon Valdez ran aground in Prince William Sound, Alaska, shortly after midnight on March 24, 1989, spilling approximately 11 million gallons of crude oil: the largest marine oil spill in the United States at the time. In the first week the oil spread throughout the central and western portions of Prince William Sound and reached the Alaska Coastal Current in the Gulf of Alaska. Once in the Alaska Coastal Current the oil was transported into lower Cook Inlet and along Shelikof Strait, up to 750 km from the location of the spill (Fig. 1). The spill's impact on the ecosystem was tremendous, with estimated losses of 250,000 seabirds, 2800 sea otters, 300 seals, and unknown numbers of fish and marine organisms (Wolfe et al., 1994). A $900 million civil settlement was awarded for damages resulting from the oil spill in 1991, with the funds to be used for restoration activities, including research and monitoring.Ahmadi, P., Chapoy, A., 2018. CO2 solubility in formation water under sequestration conditions. Fluid Phase Equilibria 463, 80-90. high pressure experimental setup was used to measure the solubility of CO2 in an aqueous solution of different salts (salinity: ～80000?ppm) at temperatures from (300–424) K and pressures up to 41?MPa. To ensure the validity of the experimental results and procedures, CO2 solubilities in deionised water were measured at the same pressure and temperature conditions. For both cases, experimental results were compared against predictions of the simplified cubic plus association equation of state (sCPA-EoS) [1] and Duan model [2]. Furthermore, the measured solubilities in deionised water were compared with literature experimental data.The average absolute deviation (%AAD) of all the measured solubilities in the mixed salts aqueous solution in comparison with predictions of the sCPA-EoS and Duan model were found to be 6.88% and 4.04%, respectively. A similar comparison was also performed for the measured CO2 solubilities in deionised water. The average absolute deviation between experimental results and predictions of the sCPA-EoS and Duan model were calculated to be 7.74% and 4.19%, respectively. The percentage average expanded uncertainty (with 95% level of confidence, k?=?2) for measurements conducted in deionised water and mixed salt aqueous solution were found to be 1.20% and 1.57%, respectively.Aitken, C.M., Head, I.M., Jones, D.M., Rowland, S.J., Scarlett, A.G., West, C.E., 2018. Comprehensive two-dimensional gas chromatography-mass spectrometry of complex mixtures of anaerobic bacterial metabolites of petroleum hydrocarbons. Journal of Chromatography A 1536, 96-109. biotransformation of petroleum hydrocarbons is an important alteration mechanism, both subsurface in geological reservoirs, in aquifers and in anoxic deep sea environments. Here we report the resolution and identification, by comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC–MS), of complex mixtures of aromatic acid and diacid metabolites of the anaerobic biodegradation of many crude oil hydrocarbons. An extended range of metabolites, including alkylbenzyl, alkylindanyl, alkyltetralinyl, alkylnaphthyl succinic acids and alkyltetralin, alkylnaphthoic and phenanthrene carboxylic acids, is reported in samples from experiments conducted under sulfate-reducing conditions in a microcosm over two years. The range of metabolites identified shows that the fumarate addition mechanism applies to the alteration of hydrocarbons with up to C8 alkylation in monoaromatics and that functionalisation of up to three ring aromatic hydrocarbons with at least C1 alkylation occurs. The GC×GC–MS method might now be applied to the identification of complex mixtures of metabolites in samples from real environmental oil spills.Ajayi, T., Anderson, B.J., Seol, Y., Boswell, R., Myshakin, E.M., 2018. Key aspects of numerical analysis of gas hydrate reservoir performance: Alaska North Slope Prudhoe Bay Unit “L-Pad” hydrate accumulation. Journal of Natural Gas Science and Engineering 51, 37-43. previous work, we reported the development of the 3D geostatistical hydrate reservoir model of "L-Pad" (Myshakin et al., 2016). In this paper, gas production sensitivity on key reservoir parameters are studied. Hydraulic communication with an aquifer and optimal depressurization strategies are subjects of investigation. Uncertainty in initial in situ permeability within 0.1–10 mD range leads to 2.0?×?108–3.5?×?108 ST m3 of gas produced over 10 years. Accounting for reservoir quality and irreducible water saturation leads to noticeable change in productivity. Sequential depressurization of hydrate-bearing units was found to be more attractive versus simultaneous depressurization.Akhilesh, K., Pappu, S., Rajapara, H.M., Gunnell, Y., Shukla, A.D., Singhvi, A.K., 2018. Early Middle Palaeolithic culture in India around 385–172 ka reframes Out of Africa models. Nature 554, 97-101. dating at the stratified prehistoric site of Attirampakkam, India, has shown that processes signifying the end of the Acheulian culture and the emergence of a Middle Palaeolithic culture occurred at 385?±?64 thousand years ago (ka), much earlier than conventionally presumed for South Asia. The Middle Palaeolithic continued at Attirampakkam until 172?±?41?ka. Chronologies of Middle Palaeolithic technologies in regions distant from Africa and Europe are crucial for testing theories about the origins and early evolution of these cultures, and for understanding their association with modern humans or archaic hominins, their links with preceding Acheulian cultures and the spread of Levallois lithic technologies. The geographic location of India and its rich Middle Palaeolithic record are ideally suited to addressing these issues, but progress has been limited by the paucity of excavated sites and hominin fossils as well as by geochronological constraints. At Attirampakkam, the gradual disuse of bifaces, the predominance of small tools, the appearance of distinctive and diverse Levallois flake and point strategies, and the blade component all highlight a notable shift away from the preceding Acheulian large-flake technologies. These findings document a process of substantial behavioural change that occurred in India at 385?±?64?ka and establish its contemporaneity with similar processes recorded in Africa and Europe. This suggests complex interactions between local developments and ongoing global transformations. Together, these observations call for a re-evaluation of models that restrict the origins of Indian Middle Palaeolithic culture to the incidence of modern human dispersals after approximately 125?ka.Akinola, A.S., Adebiyi, F.M., Santoro, A., Mastrolitti, S., 2018. Study of resin fraction of Nigerian crude oil using spectroscopic/spectrometric analytical techniques. Petroleum Science and Technology 36, 429-436. and trace metals of the resin fraction of Nigerian crude oil were analysed in order to characterise the fossil fuel. The crude oil samples were deasphaltened by n-pentane, while maltene fraction was fractionated into its components (saturates, aromatics and resin) using column chromatography. The organic compounds and elemental concentrations of the resin fraction were investigated using Fourier Transform Infrared Spectroscopy and Inductively Coupled Plasma Optical Emission Spectrometry respectively. The infrared spectra showed characteristic bands containing polar functional groups expected confirming that the resin was purely eluted. The elemental concentrations were found to be high compared to other fractions and was confirmed by their T-test values. Zinc had the highest mean concentration of 32.13 ± 35.66?mg/kg, while Mn had the least (1.14 ± 0.17?mg/kg). Results indicated that processing of the crude oil resin may cause catalyst poisoning/fouling, corrosion of equipment/pipelines. Therefore, adequate consideration of these trace metals must be taken before processing.Al-Rifai, A.a., Aqel, A., Wahibi, L.A., Alothman, Z.A., Badjah-Hadj-Ahmed, A.-Y., 2018. Carbon nanotube-based benzyl polymethacrylate composite monolith as a solid phase extraction adsorbent and a stationary phase material for simultaneous extraction and analysis of polycyclic aromatic hydrocarbon in water. Journal of Chromatography A 1535, 17-26. composite of multi-walled carbon nanotubes incorporated into a benzyl methacrylate-co-ethylene dimethacrylate porous monolith was prepared, characterized and used as solid phase adsorbent and as stationary phase for simultaneous extraction and separation of ten polycyclic aromatic hydrocarbons, followed by nano-liquid chromatography analysis. The extraction and chromatographic parameters were optimized with regard to the extraction efficiency and the quality of chromatographic analytes separation. Under the optimized conditions, all PAHs were separated in 13?min with suitable resolution values (Rs?=?1.74–3.98). Addition of a small amount of carbon nanotubes (0.1% with respect to monomers) to the polymerization mixture increased the efficiency for the separation column to over 41,700?plates?m?1 for chrysene at flow rate of 0.5?μL?min?1. The method showed a wide linear range (1–500?μg?L?1 with R2 more than 0.9938), acceptable extraction repeatability (RSDs?<?6.4%, n?=?3) and reproducibility (RSDs?<?12.6%, five parallel-made solid phase extraction cartridges) and satisfactory detection limits (0.02–0.22?μg?L?1). Finally, the proposed method was successfully applied to the detection of polycyclic aromatic hydrocarbons in environmental water samples. After a simple extraction procedure with preconcentration factor equal to 100, the average recovery values in ultra-pure, tap and sea water samples were found to be in the range 81.3–95.4% with %RSD less than 6.4. Again, the presence of carbon nanotubes (0.3% relatively to monomers) in native polymer enhanced the extraction performance for the solid phase adsorbent up to 78.4%. The application of the monoliths modified with CNTs in extraction and nano-scale liquid chromatography for analysis of environmental samples offered several advantages; it demonstrated an acceptable precision, low detection limits, good reproducibility, satisfying recoveries and wide dynamic linear ranges.Al-Said, T., Naqvi, S.W.A., Al-Yamani, F., Goncharov, A., Fernandes, L., 2018. High total organic carbon in surface waters of the northern Arabian Gulf: Implications for the oxygen minimum zone of the Arabian Sea. Marine Pollution Bulletin 129, 35-42. of total organic carbon (TOC) for two years in Kuwaiti waters showed high TOC levels (101.0–318.4, mean 161.2?μM) with maximal concentrations occurring within the polluted Kuwait Bay and decreasing offshore, indicating substantial anthropogenic component. Analysis of winter-time data revealed a large increase in density over the past four decades due to decrease in Shatt Al-Arab runoff, implying that the dissolved/suspended organic matter in surface waters of the northern Gulf could be quickly injected into the Gulf Deep Water (GDW). Our measurements together with an analysis of previously collected/published data suggest that the recent summer-time declining trend in oxygen in the GDW might be related to eutrophication. Higher preformed TOC and lower preformed dissolved oxygen contents of the high-salinity water mass that flows out of the Gulf and ventilates the mesopelagic oxygen minimum zone (OMZ) of the Northwestern Indian Ocean may cause expansion/intensification of the regional OMZ.Albéric, P., Pérez, M.A.P., Moreira-Turcq, P., Benedetti, M.F., Bouillon, S., Abril, G., 2018. Variation of the isotopic composition of dissolved organic carbon during the runoff cycle in the Amazon River and the floodplains. Comptes Rendus Geoscience 350, 65-75. the relative scarcity of stable isotope data on dissolved organic carbon (DOC) in the Amazon Basin, we hypothesized that the variability in DOC sources may be underestimated in such major river basins. To explore the links between the mainstem and tributaries and the floodplain, particular efforts were made during five distinct cruises at different stages of the hydrograph between October 2008 and January 2011, to document the spatial and temporal variation of DOC concentrations and δ13C-DOC in the central Amazon River system (Brazil). Based on more than 200 data, the spatial and temporal variability of δ13C-DOC values was found to be larger than previously reported in the same area. Although a small range of variation was observed throughout the hydrological cycle in the upper reach of the studied section (–29.2 to –29.5‰ in the Rio Negro and –28.7 to –29.0‰ in the Rio Solim?es), a much larger one (–28.0 to –34.6‰) was found in the lower reach of the river, as the proportion of open lakes increased downstream in the floodplains. The low variability in the upper reaches suggests constant and homogeneous DOC sources from upland soils and flooded forest, while lower δ13C-DOC values recorded in the lower reach mainstem at high and falling waters can be attributed to a greater export of plankton-derived 13C-depleted DOC from flooded lakes. Noteworthy are the higher δ13C-DOC values measured in the Rio Madeira and the associated flooded lakes (–26.5 to –28.8‰), which may reflect the imprint from upland headwaters and a weaker density of flooded forest in the watershed. The higher δ13C-DOC values observed in the lower reach during low waters are still not fully understood. Floating meadows principally consisting of C4 macrophytes were found to increase δ13C-DOC values by ～1.5‰ in their vicinity, but this impact was no longer noticeable at distances of ～10 m from the plant rafts. This rather modest 13C-enrichment suggests rapid decomposition and/or dilution of this wetland-derived DOC.Albers, C.N., Kramsh?j, M., Rinnan, R., 2018. Rapid mineralization of biogenic volatile organic compounds in temperate and Arctic soils. Biogeosciences Discussions 2018, 1-18. volatile organic compounds (BVOCs) are produced by all life forms. Their release into the atmosphere is important with regards to a number of physical and chemical processes and great effort has been put into determining sources and sinks of these compounds in recent years. Soil microbes as a possible sink for BVOCs in the atmosphere has been suggested, however, experimental evidence for this sink is scarce despite its potentially high importance to both carbon cycling and atmospheric concentrations of these gases. We therefore conducted a study with a number of commonly occurring BVOCs labelled with 14C and modified existing methods to study mineralization of these compounds to 14CO2 in four different top soils. Five of the six BVOCs were rapidly mineralized by microbes in all soils. However, great differences were observed with regards to speed of mineralization, extent of mineralization and variation between soil types. Methanol, benzaldehyde, acetophenone and the oxygenated monoterpene geraniol were mineralized within hours in all soils. The hydrocarbon monoterpene p-cymene was mineralized rapidly in soil from a coniferous forest but slower in soil from and adjacent beech stand while chloroform was mineralized slowly in all soils. From our study it is clear that soil microbes are able to degrade completely BVOCs released by aboveground vegetation as well as BVOCs released by soil microbes and plant roots. In addition to the possible atmospheric implications of this degradation the very fast mineralization rates are likely important in shaping the net BVOC emissions from soil and it is possible that BVOC formation and degradation may be an important but little recognized part of internal carbon cycling in soil.Alexander, M., Engel, L.S., Olaiya, N., Wang, L., Barrett, J., Weems, L., Schwartz, E.G., Rusiecki, J.A., 2018. The Deepwater Horizon oil spill Coast Guard cohort study: A cross-sectional study of acute respiratory health symptoms. Environmental Research 162, 196-202.: Over 8500 United States Coast Guard (USCG) personnel were deployed in response to the Deepwater Horizon (DWH) oil spill; however, human respiratory effects as a result of spill-related exposures are relatively unknown.Methods: USCG personnel who responded to the DWH oil spill were queried via survey on exposures to crude oil and oil dispersant, and acute respiratory symptoms experienced during deployment. Adjusted log binomial regressions were used to calculate prevalence ratios (PRs) and 95% confidence intervals (CI), investigating the associations between oil spill exposures and respiratory symptoms.Results: 4855 USCG personnel completed the survey. More than half (54.6%) and almost one-fourth (22.0%) of responders were exposed to crude oil and oil dispersants, respectively. Coughing was the most prevalent symptom (19.4%), followed by shortness of breath (5.5%), and wheezing (3.6%). Adjusted analyses showed an exposure-response relationship between increasing deployment duration and likelihood of coughing, shortness of breath, and wheezing in the pre-capping period. A similar pattern was observed in the post-capping period for coughing and wheezing. Adjusted analyses revealed increased PRs for coughing (PR=1.92), shortness of breath (PR=2.60), and wheezing (PR=2.68) for any oil exposure. Increasing frequency of inhalation of oil was associated with increased likelihood of all three respiratory symptoms. A similar pattern was observed for contact with oil dispersants for coughing and shortness of breath. The combination of both oil and oil dispersants presented associations that were much greater in magnitude than oil alone for coughing (PR=2.72), shortness of breath (PR=4.65), and wheezing (PR=5.06).Conclusions: Results from the present study suggested strong relationships between oil and oil dispersant exposures and acute respiratory symptoms among disaster responders. Future prospective studies will be needed to confirm these findings.Alexandrino, G.L., de Sousa Júnior, G.R., de A.M. Reis, F., Augusto, F., 2018. Optimizing loop-type cryogenic modulation in comprehensive two-dimensional gas chromatography using time-variable combination of the dual-stage jets for analysis of crude oil. Journal of Chromatography A 1536, 82-87. enhanced chromatographic capability of the comprehensive two-dimensional gas chromatography (GC × GC) has already found several applications in analytical chemistry comprising complex samples. However, setting the appropriate chromatographic conditions that maximize sensitivity and separation efficiency in GC × GC may be more difficult than in conventional one-dimension gas chromatography, mainly due to the additional parameters strictly related to the modulation. Loop-type cryogenic modulators have been currently used for crude oil analysis using GC × GC, requiring sometimes a laborious try-and-error procedure to properly tune the dual-jets elapsed times on modulation. In this work, the advantages of choosing a time-variable combination of cold and hot jets pulses in a loop-type cryogenic modulator is presented when performing the fingerprinting analysis of crude oils using GC × GC-QMS, contrary to the conventional procedure based on a single combination for the dual-stage jets. A design of experiments approach is proposed to most effectively optimize the time-variable combination of the dual-jets elapsed times while modulating the wide hydrocarbons range along the GC × GC analysis. The most abundant classes of hydrocarbons contained in the maltenes fraction of a crude oil sample, such as paraffins, aromatics, steranes and hopanes were successfully resolved.Alfarge, D., Wei, M., Bai, B., 2017. Data analysis for CO2-EOR in shale-oil reservoirs based on a laboratory database. Journal of Petroleum Science and Engineering 162, 697-711. resources have played a significant role in changing oil industry plans recently. Shale formations in North America such as Bakken, Niobrara, and Eagle Ford have huge oil in place, 100–900 Billion barrels of recoverable oil in Bakken only. However, the primary oil recovery is still low as 5–10%. EOR methods are currently considered as a new concept in unconventional reservoirs due to the immature information about these plays. Injecting carbon dioxide (CO2) might be the most potential strategy to improve oil recovery in such complex plays (Alfarge et al., 2017a,b).Jin et al. (2016) conducted an experimental study to investigate improving oil recovery by CO2 injection in 21 natural preserved core samples from Bakken Petroleum System (BPS). Their experimental results indicated that CO2 injection has a significant potential to improve oil transportability in these Nano-pores formations. In this study, data analysis for feasibility of CO2-EOR has been conducted on 95 cases of natural preserved cores collected from different formations including 44 cases from Middle Bakken, 26 cases from Lower Bakken, 17 from Upper Bakken, 4 cases from Three Forks, and 4 cases from unknown formation/formations. The relationship between the improved oil recovery by the injected CO2 and 6 rock properties including porosity, permeability, mean pore throat radius, total organic carbon content (TOC), water saturation, and oil saturation has been separately determined and physically discussed. Furthermore, the relationships between the improved oil recovery obtained by the injected CO2 and 4 operating parameters including CO2 bath pressure, CO2 bath temperature, and core sample bulk size, and exposing time have been also separately investigated. A Proxy model to associate the functionality of the improved oil recovery by CO2 injection and these 10 parameters have been constructed. Moreover, statistical methods for Design of Experiments (DOE) have been used to rank the most important parameters affecting CO2-EOR performance in the microscale level (lab scale) of these unconventional reservoirs. This study provides an important set of lab-based data obtained from natural preserved cores to find out the applicability of CO2-EOR in these unconventional reservoirs. Also, this research demonstrates some key points which could help in understanding CO2-EOR mechanisms in shale plays since they are much complex and very different from conventional formations.AlHammadi, M., Mahzari, P., Sohrabi, M., 2018. Fundamental investigation of underlying mechanisms behind improved oil recovery by low salinity water injection in carbonate rocks. Fuel 220, 345-357. underlying mechanisms of additional oil recovery by low salinity water injection (LSWI) have remained poorly understood. The main objective of this investigation is to examine the relative dominancy of different processes taking place during LSWI in carbonate rocks. An integrated approach was employed to study the role of fluid/fluid (micro-dispersion formation) and rock/fluid (geochemical processes) interactions that can impact oil recovery. Firstly, a number of different crude oils were analysed, screened and ranked, based on their propensity to form micro-dispersions. From this bank of samples, two crude oil samples were selected with similar physical properties but high and low propensities for forming micro-dispersion. In addition, a third sample was prepared from the positive crude oil (the high micro-dispersion sample) by removing oil compounds associated with micro-dispersion formation. Three coreflood experiments were designed to assess the role of crude oil/brine interactions in oil recovery by LSWI in tertiary scenarios. The outcome of the coreflood experiments using the same rock and brine compositions should demonstrate the dominant mechanism in improving oil recovery.When low salinity water (below 10,000?ppm) was injected in tertiary mode, the crude oil with a positive tendency to form micro-dispersions demonstrated a significant additional oil recovery of 6.3%. In contrast, no additional oil recovery was observed from LSWI with the crude oil sample that had reacted poorly to low salinity water (i.e. not formed micro-dispersion) nor with the treated sample. Using a novel method, the mineralogy of the rock was identified, which indicated the presence of anhydrite minerals. A series of spontaneous imbibition tests were also performed, which indicated similar mixed-wet conditions for the systems, which would make the systems comparable. The results of this fundamental work have demonstrated that despite the occurrence of geochemical processes, micro-dispersion formation appears to be the more dominant mechanism behind the IOR obtained by LSWI in carbonate rocks.Alharthy, N., Teklu, T.W., Kazemi, H., Graves, R.M., Hawthorne, S.B., Braunberger, J., Kurtoglu, B., 2018. Enhanced oil recovery in liquid-rich shale reservoirs: Laboratory to field, SPE-175034-PA. SPE Reservoir Evaluation and Engineering 21, 137-159. of tight oil from shale reservoirs in North America reduces oil imports and has better economics than natural gas. Currently, there is a strong interest in oil production from Bakken, Eagle Ford, Niobrara, and other tight formations. However, oil-recovery fraction for Bakken remains low, which is approximately 4–6% of the oil in place. Even with this low oil-recovery fraction, a recent United States Geological Survey study stated that the Bakken and Three Forks recoverable reserves are estimated to be 7.4 billion bbl; thus, a large volume of oil will remain unrecovered, which was the motivation to investigate the feasibility of enhanced oil recovery (EOR) in liquid-rich shale reservoirs such as Bakken.In this paper, we will present both laboratory and numerical modeling of EOR in Bakken cores by use of carbon dioxide (CO2), methane/ethane-solvent mixture (C1/C2), and nitrogen (N2). The laboratory experiments were conducted at the Energy and Environmental Research Center (EERC). The experiments recovered 90+% oil from several Middle Bakken cores and nearly 40% from Lower Bakken cores. To decipher the oil-recovery mechanisms in the experiments, a numerical compositional model was constructed to match laboratory-oil-recovery results. We concluded that solvent injection mobilizes matrix oil by miscible mixing and solvent extraction in a narrow region near the fracture/matrix interface, thus promoting countercurrent flow of oil from the matrix instead of oil displacement through the matrix. Specifically, compositional-modeling results indicate that the main oil-recovery mechanism is miscible oil extraction at the matrix/fracture interface region. However, the controlling factors include repressurization, oil swelling, viscosity and interfacial-tension (IFT) reduction, diffusion/advection mass transfer, and wettability alteration.We scaled up laboratory results to field applications by means of a compositional numerical model. For field applications, we resorted to the huff ’n’ puff protocol to assess the EOR potential for a North Dakota Middle Bakken well. We concluded that long soak times yield only a small amount of additional oil compared with short soak times, and reinjecting wet gas, composed of C1, C2, C3, and C4+, produces nearly as much oil as CO2 injection.Aljariri Alhesan, J.S., Fei, Y., Marshall, M., Jackson, W.R., Qi, Y., Chaffee, A.L., Cassidy, P.J., 2018. Long time, low temperature pyrolysis of El-Lajjun oil shale. Journal of Analytical and Applied Pyrolysis 130, 135-141. is continuing interest in in situ production of oil from oil shale, particularly for deep deposits and for environmental reasons. Such production would involve long-time, low temperature pyrolysis. Accordingly, reactions of El-Lajjun oil shale have been carried out under N2 for 7, 14 and 28?days at temperatures in the range 240–320?°C. The conversion plateaued at 300?°C and above at a value of about 80?wt% dmmf and was the same for 7 and 14?day pyrolysis. The total conversion decreased by 15% as the temperature decreased to 280?°C. The lower conversions at 240 and 260?°C were the same for 14 and 28?days but oil yield increased at the expense of asphaltene for the longer time. Sulfur content of the oil?+?asphaltene decreased with increasing reaction temperature (240–300?°C) and time (280–300?°C) from 13?wt% to a plateau of about 7?wt%. The characteristics of the oil and oil?+?asphaltene changed steadily with temperature up to 300?°C, but increasing the temperature further to 320?°C had little effect. The results show that high conversion to products of good characteristics can be obtained for reactions at sufficiently long times at temperatures as low as 300?°C.AlSumaiti, A.M., Hashmet, M.R., AlAmeri, W.S., Anto-Darkwah, E., 2018. Laboratory study of CO2 foam flooding in high temperature, high salinity carbonate reservoirs using co-injection technique. Energy & Fuels 32, 1416-1422. this research, an ethoxylated amine surfactant is co-injected with CO2 in a series of coreflooding experiments at typical Middle Eastern reservoir conditions of high temperature, high salinity, and in situ foam is generated to reduce gas mobility in the absence of oil. The effects of reservoir permeability, injection rates, and foam quality on mobility reduction factor (MRF) and apparent viscosity of foam are discussed. In the absence of oil, an optimum foam quality of 80% is obtained using 1 wt % of surfactant solution. Shear thinning foams with viscosities ranging between 0.9 and 2.4 cP were formed at all velocities tested in this study. MRFs of 50 and 70 were obtained, respectively, in 70 and 240 mD cores at 80% foam quality, confirming that foam strength increases with increasing rock permeability. After determination of optimum foam quality and flow rate, a final coreflooding experiment was conducted in the presence of oil to quantify the effect of oil presence on foam generation and to observe the recovery performances of supercritical CO2 and CO2 foam for secondary and tertiary recovery injections. In the presence of oil, relatively weak foams were generated in a 50 mD core having apparent viscosities of 0.66, 1.65, and 3.29 cP at the tested co-injection flow rates of 0.2, 0.5, and 1 mL/min at 80% foam quality. A total recovery factor of 88.32% was obtained, with CO2 and CO2 foam floods contributing 79.34% and 8.98%, respectively.Altair, T., de Avellar, M.G.B., Rodrigues, F., Galante, D., 2018. Microbial habitability of Europa sustained by radioactive sources. Scientific Reports 8, Article 260. is an increasing interest in the icy moons of the Solar System due to their potential habitability and as targets for future exploratory missions, which include astrobiological goals. Several studies have reported new results describing the details of these moons’ geological settings; however, there is still a lack of information regarding the deep subsurface environment of the moons. The purpose of this article is to evaluate the microbial habitability of Europa constrained by terrestrial analogue environments and sustained by radioactive energy provided by natural unstable isotopes. The geological scenarios are based on known deep environments on Earth, and the bacterial ecosystem is based on a sulfate-reducing bacterial ecosystem found 2.8?km below the surface in a basin in South Africa. The results show the possibility of maintaining the modeled ecosystem based on the proposed scenarios and provides directions for future models and exploration missions for a more complete evaluation of the habitability of Europa and of icy moons in general.Andrade, L.L.P.R., Rajagopal, K., 2018. Models for estimating the viscosity of paraffinic–naphthenic live crude oils. Energy & Fuels 32, 2622-2629. is an important property of live crude oil used in design and operation of production processes. Eleven widely used empirical correlations for estimating undersaturated oil viscosity were evaluated using measured undersaturated oil viscosity for live crude oils from primary separators of 10 Brazilian oil wells. The oil samples were characterized as paraffinic–naphthenic crudes. The empirical correlations were found to be inadequate to represent the measured data. The better literature models present average absolute percent relative errors of 1.18% and 1.40% but show wider scatter of data. For more accurate estimates of undersaturated oil viscosity of paraffinic–naphthenic live crudes oils, a new model based on Eyring theory is proposed, and this model correlates the experimental data with average absolute percent relative error of 0.97%.Andrault, D., Pesce, G., Manthilake, G., Monteux, J., Bolfan-Casanova, N., Chantel, J., Novella, D., Guignot, N., King, A., Itié, J.-P., Hennet, L., 2018. Deep and persistent melt layer in the Archaean mantle. Nature Geoscience 11, 139-143. transition from the Archaean to the Proterozoic eon ended a period of great instability at the Earth’s surface. The origin of this transition could be a change in the dynamic regime of the Earth’s interior. Here we use laboratory experiments to investigate the solidus of samples representative of the Archaean upper mantle. Our two complementary in situ measurements of the melting curve reveal a solidus that is 200–250?K lower than previously reported at depths higher than about 100?km. Such a lower solidus temperature makes partial melting today easier than previously thought, particularly in the presence of volatiles (H2O and CO2). A lower solidus could also account for the early high production of melts such as komatiites. For an Archaean mantle that was 200–300?K hotter than today, significant melting is expected at depths from 100–150?km to more than 400?km. Thus, a persistent layer of melt may have existed in the Archaean upper mantle. This shell of molten material may have progressively disappeared because of secular cooling of the mantle. Crystallization would have increased the upper mantle viscosity and could have enhanced mechanical coupling between the lithosphere and the asthenosphere. Such a change might explain the transition from surface dynamics dominated by a stagnant lid on the early Earth to modern-like plate tectonics with deep slab subduction.Aoyama, S., Ueno, Y., 2018. Multiple sulfur isotope constraints on microbial sulfate reduction below an Archean seafloor hydrothermal system. Geobiology 16, 107-120. sulfate reduction is among the most ubiquitous metabolic processes on earth. The oldest evidence of microbial sulfate reduction appears in the ca. 3.5 Ga Dresser Formation in the North Pole area of Pilbara Craton in Western Australia. That evidence was found through analysis of quadruple sulfur isotopes of sulfate and sulfide minerals deposited on the seafloor. However, the activity of microbial sulfate reduction below the Archean seafloor remains poorly understood. Here, we report the quadruple sulfur isotopic compositions of sulfide minerals within hydrothermally altered seafloor basalt and less altered basaltic komatiite collected from the North Pole Dome area. The Δ33S values of the sulfide minerals were nonzero negative, suggesting that sulfate reduction occurred below the Archean seafloor. To constrain the substrate sulfate sources and sulfate reduction processes, we constructed a numerical model. Comparing the modeled and observed sulfur isotopes, we show that the substrate sulfate comprises seawater sulfate with a negative Δ33S anomaly and 34S-enriched sulfate with no anomalous Δ33S. The latter component probably represents sulfate produced by local hydrothermal processes. The maximum sulfur isotopic fractionation between the putative substrate sulfate and the observed sulfide minerals within the altered basalt and basaltic komatiite is 35‰, which is consistent with a microbial origin. Alternatively, thermochemical sulfate reduction may also produce sulfide. However, considering the hydrothermal temperature inferred from the metamorphic grade of the altered basalt, the sulfur isotopic fractionation produced by inorganic sulfate reduction is probably below 20‰. Collectively, larger fractionations imply the involvement of biological sulfate reduction processes, both in the hydrothermal system below the seafloor and in less altered subsurface settings.Appenzeller, T., 2018. Europe's first artists were Neandertals. Science 359, 852-853. once, the fractious scientists who study the Neandertals agree about something: that a study on p. 912 has dropped a bombshell on their field, by presenting the most persuasive case yet that our vanished cousins had the cognitive capacity to create art. Once seen as brute cavemen, Neandertals have gained stature as examples of sophisticated technology and behavior have turned up in their former territory across Europe. But few researchers imagined them engaging in one of the most haunting practices in human prehistory: creating paintings—vehicles for symbolic expression—in the darkness of caves.Now, archaeologists may have to accept that Neandertals were the original cave artists. A team of dating experts and archaeologists reports that simple creations—the outline of a hand, an array of lines, and a painted cave formation—from three caves in Spain all date to more than 64,800 years ago, at least 20,000 years before modern humans reached Europe. Shells from a fourth Spanish cave, pigment-stained and pierced as if for use as body ornaments, are even older, a team including several of the same researchers reports in a second paper, in Science Advances. Some researchers had already attributed the shells to Neandertals, but the new dates leave little doubt.The shells amount to only a handful and might have been perforated naturally, causing some researchers to question their significance. Not so the paintings. “Most of my colleagues are going to be stunned,” says Jean-Jacques Hublin of the Max Planck Institute (MPI) for Evolutionary Anthropology in Leipzig, Germany, who was not involved in either study. “People saw cave painting as a major gap between Neandertals and modern humans. This discovery reduces the distance.”Just how much is the question. Jo?o Zilh?o of the University of Barcelona in Spain, an author of both papers, has spent years pressing the case that Neandertals were the mental equals of modern humans, and he sees the newly dated paintings and shells as full vindication. “I'd like to see the expression on some faces as they read the papers,” he says. Hublin, who accepts that Neandertals were cognitively sophisticated but believes their cultural achievements fell short of modern humans', is impatient with what he sees as Zilh?o's absolutism. “What is the goal—to say that Neandertals were just like modern humans? That is a very far stretch.”And some researchers, trying to absorb findings that fly in the face of their longtime view of Neandertals, aren't sure what to think. “I find [it] incredibly challenging,” says Shannon McPherron of MPI, whose own work has cast doubt on claims that Neandertals buried their dead or made systematic use of fire. The new dates, he says, have “shattered my model of Neandertal behavior.”With rare exceptions, cave art could not be directly dated until recently, making it hard to challenge the assumption that the artists were modern humans. For one thing, most cave paintings lack organic residues that can be dated by the radioactive decay of carbon isotopes. But in the early 2000s, scientists devised an alternative dating strategy based on the thin layer of calcite that can form when groundwater seeps down a cave wall and across a painting. The water contains a smattering of uranium atoms that decay into a distinctive isotope of thorium, which accumulates in the calcite over millennia. Grind a few flecks of calcite off a cave painting, measure the ratio of uranium and thorium isotopes, and you can read out the age of the calcite. The underlying painting must be at least that old—and could be much older.It's not easy, says MPI's Dirk Hoffmann, who was among the first to apply uranium-thorium dating to cave paintings and is the first author of both papers. “The challenge is to find these calcites. You need a wall where you occasionally have a little water coming in that deposits calcite without damaging the painting.” Then comes the “nerve-wracking” task of scraping off the calcite without marring the pigment, and the painstaking analysis of a sample of few milligrams. Hoffmann and his colleagues applied the technique to cave art across Italy, France, Portugal, and Spain. Most of the dates fell within the European reign of modern humans, which began 40,000 to 45,000 years ago. But in the three cases described in Science, the paintings are far too old to have been made by them.“To me the biggest question is how good is the dating,” says Harold Dibble of the University of Pennsylvania, who has long challenged claims of sophisticated Neandertal behavior. But others see little reason for doubt. Multiple samples from each painting yielded consistent results, and in several cases Hoffmann and his colleagues analyzed scrapings from increasing depths in the calcite layer. The dates grew older as they approached the pigment, adding credibility. “I am confident that the [uranium-thorium] dates are correct,” says Rainer Grün, an expert in the technique at Griffith University in Nathan, Australia, who did not take part in the work.Zilh?o predicts that other cave paintings will prove equally ancient, if not more so. “This is just scratching the surface of an entirely new world.” He cites two other finds as evidence of a long Neandertal tradition of art and ritual. One is a pair of corral-shaped structures, the larger one more than 6 meters across, assembled from broken stalagmites and scorched by fire, found by cavers more than 300 meters deep in Bruniquel Cave in France. In 2016, a French-led team reported in Nature that the structures were built some 175,000 years ago—presumably by Neandertals, perhaps for ritual purposes. And then there are the colored shells from Cueva de los Aviones, a sea cave in southern Spain, where Hoffmann's uranium-thorium dating of a calcite crust covering the objects has just yielded an age of more than 115,000 years.But was this Neandertal artistic creativity equivalent to the art and symbolism practiced by modern humans? At sites across Africa, our direct ancestors were making shell beads and etching abstract designs into egg shells and minerals 80,000 years ago and more. Neandertal achievements were fully comparable, Zilh?o insists, and to suggest otherwise implies a double standard.Hublin disagrees. The startling new dates for the paintings “show that Neandertals had the same potential as modern humans in a number of domains,” he acknowledges. But he and others see differences in cognition and culture that even the new research does not erase. And Hublin notes that soon after their arrival in Europe, “modern humans replaced [Neandertals], and there are reasons.”Like the gap between these two kinds of humans, the rift among Neandertal experts has narrowed. But it has not yet closed.Applin, D.M., Izawa, M.R.M., Cloutis, E.A., Gillis-Davis, J.J., Pitman, K.M., Roush, T.L., Hendrix, A.R., Lucey, P.G., 2018. Ultraviolet spectral reflectance of carbonaceous materials. Icarus 307, 40-82. number of planetary spacecraft missions have carried instruments with sensors covering the ultraviolet (UV) wavelength range. However, there exists a general lack of relevant UV reflectance laboratory data to compare against these planetary surface remote sensing observations in order to make confident material identifications. To address this need, we have systematically analyzed reflectance spectra of carbonaceous materials in the 200–500?nm spectral range, and found spectral-compositional-structural relationships that suggest this wavelength region could distinguish between otherwise difficult-to-identify carbon phases. In particular (and by analogy with the infrared spectral region), large changes over short wavelength intervals in the refractive indices associated with the trigonal sp2π–π* transition of carbon can lead to Fresnel peaks and Christiansen-like features in reflectance. Previous studies extending to shorter wavelengths also show that anomalous dispersion caused by the σ–σ* transition associated with both the trigonal sp2 and tetrahedral sp3 sites causes these features below λ?=?200?nm. The peak wavelength positions and shapes of π–π* and σ–σ* features contain information on sp3/sp2, structure, crystallinity, and powder grain size. A brief comparison with existing observational data indicates that the carbon fraction of the surface of Mercury is likely amorphous and submicroscopic, as is that on the surface of the martian satellites Phobos and Deimos, and possibly comet 67P/Churyumov–Gerasimenko, while further coordinated observations and laboratory experiments should refine these feature assignments and compositional hypotheses. The new laboratory diffuse reflectance data reported here provide an important new resource for interpreting UV reflectance measurements from planetary surfaces throughout the solar system, and confirm that the UV can be rich in important spectral information.Aranguren, B., Revedin, A., Amico, N., Cavulli, F., Giachi, G., Grimaldi, S., Macchioni, N., Santaniello, F., 2018. Wooden tools and fire technology in the early Neanderthal site of Poggetti Vecchi (Italy). Proceedings of the National Academy of Sciences 115, 2054-2059.: Wood is a widely available and versatile material, which has admittedly played a fundamental role in all human history. Wood, however, is most vulnerable to decomposition. Hence, its use is very rarely documented during prehistory. The present study yields new insights into the cognitive abilities of the early Neanderthals in wooden tool production and pyrotechnology. The early Neanderthals from the late Middle Pleistocene site of Poggetti Vecchi (central Italy) were able to choose the appropriate timber and to process it with fire to produce tools. The artifacts recall the so-called “digging sticks,” multipurpose tools used by all hunter-gatherer societies.Abstract: Excavations for the construction of thermal pools at Poggetti Vecchi (Grosseto, Tuscany, central Italy) exposed a series of wooden tools in an open-air stratified site referable to late Middle Pleistocene. The wooden artifacts were uncovered, together with stone tools and fossil bones, largely belonging to the straight-tusked elephant Paleoloxodon antiquus. The site is radiometrically dated to around 171,000 y B.P., and hence correlated with the early marine isotope stage 6 [Benvenuti M, et al. (2017) Quat Res 88:327–344]. The sticks, all fragmentary, are made from boxwood (Buxus sempervirens) and were over 1 m long, rounded at one end and pointed at the other. They have been partially charred, possibly to lessen the labor of scraping boxwood, using a technique so far not documented at the time. The wooden artifacts have the size and features of multipurpose tools known as “digging sticks,” which are quite commonly used by foragers. This discovery from Poggetti Vecchi provides evidence of the processing and use of wood by early Neanderthals, showing their ability to use fire in tool making from very tough wood.Araújo, B.Q., Aquino Neto, F.R., Azevedo, D.A., 2018. Occurrence of extended tetracyclic polyprenoid series in crude oils. Organic Geochemistry 118, 27-35. homologous series of tetracyclic polyprenanes from C24 to C41 was identified in crude oils from Espírito Santo Basin (Brazil) by comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC×GC–TOFMS) and gas chromatography–tandem mass spectrometry (GC–MS-MS) analyses. These products were separately characterized by elution order in first- and second-dimension retention times (1tR and 2tR, respectively), time-of-flight mass spectra (TOFMS), MRM chromatograms, product ion spectra including diagnostic ions at m/z 191, m/z 259 and m/z 149?+?14n (n?=?0–17), the latter a key mass fragment for the evaluation of side chain extension at the C-18 position in tetracyclic polyprenoids. The tetracyclic compounds were thus identified as scalarane-like structures related to abundant C30 tetracyclic polyprenoids, an important indicator of input from fresh to brackish water paleoenvironments.Arsic, M., Teasdale, P.R., Welsh, D.T., Johnston, S.G., Burton, E.D., Hockmann, K., Bennett, W.W., 2018. Diffusive gradients in thin films reveals differences in antimony and arsenic mobility in a contaminated wetland sediment during an oxic-anoxic transition. Environmental Science & Technology 52, 1118-1127. (Sb) and arsenic (As) are priority environmental contaminants that often co-occur at mining-impacted sites. Despite their chemical similarities, Sb mobility in waterlogged sediments is poorly understood in comparison to As, particularly across the sediment–water interface (SWI) where changes can occur at the millimeter scale. Combined diffusive gradients in thin films (DGT) and diffusive equilibration in thin films (DET) techniques provided a high resolution, in situ comparison between Sb, As, and iron (Fe) speciation and mobility across the SWI in contaminated freshwater wetland sediment mesocosms under an oxic–anoxic–oxic transition. The shift to anoxic conditions released Fe(II), As(III), and As(V) from the sediment to the water column, consistent with As release being coupled to the reductive dissolution of iron(III) (hydr)oxides. Conversely, Sb(III) and Sb(V) effluxed to the water column under oxic conditions and fluxed into the sediment under anoxic conditions. Porewater DGT–DET depth profiles showed apparent decoupling between Fe(II) and Sb release, as Sb was primarily mobilized across the SWI under oxic conditions. Solid-phase X-ray absorption spectroscopy (XAS) revealed the presence of an Sb(III)-S phase in the sediment that increased in proportion with depth and the transition from oxic to anoxic conditions. The results of this study showed that Sb mobilization was decoupled from the Fe cycle and was, therefore, more likely linked to sulfur and/or organic carbon (e.g., most likely authigenic antimony sulfide formation or Sb(III) complexation by reduced organic sulfur functional groups).Astudillo-García, C., Slaby, B.M., Waite, D.W., Bayer, K., Hentschel, U., Taylor, M.W., 2018. Phylogeny and genomics of SAUL, an enigmatic bacterial lineage frequently associated with marine sponges. Environmental Microbiology 20, 561-576. marine sponges contain dense and diverse communities of associated microorganisms. Members of the ‘sponge-associated unclassified lineage’ (SAUL) are frequently recorded from sponges, yet little is known about these bacteria. Here we investigated the distribution and phylogenetic status of SAUL. A meta-analysis of the available literature revealed the widespread distribution of this clade and its association with taxonomically varied sponge hosts. Phylogenetic analyses, conducted using both 16S rRNA gene-based phylogeny and concatenated marker protein sequences, revealed that SAUL is a sister clade of the candidate phylum ‘Latescibacteria’. Furthermore, we conducted a comprehensive analysis of two draft genomes assembled from sponge metagenomes, revealing novel insights into the physiology of this symbiont. Metabolic reconstruction suggested that SAUL members are aerobic bacteria with facultative anaerobic metabolism, with the capacity to degrade multiple sponge- and algae-derived carbohydrates. We described for the first time in a sponge symbiont the putative genomic capacity to transport phosphate into the cell and to produce and store polyphosphate granules, presumably constituting a phosphate reservoir for the sponge host in deprivation periods. Our findings suggest that the lifestyle of SAUL is symbiotic with the host sponge, and identify symbiont factors which may facilitate the establishment and maintenance of this relationship.Avice, G., Bekaert, D.V., Chennaoui Aoudjehane, H., Marty, B., 2018. Noble gases and nitrogen in Tissint reveal the composition of the Mars atmosphere. Geochemical Perspectives Letters 6, 11-16. planetology is crucial to unravel the origin and evolution of volatile elements on terrestrial planets. We report precise measurements of the elemental and isotopic composition of nitrogen and noble gases in the Martian meteorite Tissint. Ar-N2 correlations confirm discrepancies between results from Viking and Martian meteorites and those from the Mars Science Laboratory (MSL) mission. The Martian atmospheric 40Ar/36Ar ratio is estimated to be 1714 ± 170 (1σ), lower than the value determined by Viking but in agreement with, and with higher precision than, data from MSL. We confirm a solar wind-like origin for Martian Kr and Xe. Excesses on light Kr isotopes are lower than those measured by MSL. Cosmogenic excesses in the Xe isotopic spectrum could have been produced in space during exposure of the Tissint parent body to cosmic rays.Aydinoglu, A.U., Ta?k?n, Z., 2018. Origins of life research: A bibliometric approach. Origins of Life and Evolution of Biospheres 48, 55-71. study explores the collaborative nature and interdisciplinarity of the origin(s) of life (OoL) research community. Although OoL research is one of the oldest topics in philosophy, religion, and science; to date there has been no review of the field utilizing bibliometric measures. A dataset of 5647 publications that are tagged as OoL, astrobiology, exobiology, and prebiotic chemistry is analyzed. The most prolific authors (Raulin, Ehrenfreund, McKay, Cleaves, Cockell, Lazcano, etc.), most cited scholars and their articles (Miller 1953, Gilbert 1986, Chyba & Sagan 1992, W?chtersh?user 1988, etc.), and popular journals (Origins of Life and Evolution of Biospheres and Astrobiology) for OoL research are identified. Moreover, interdisciplinary research conducted through research networks, institutions (NASA, Caltech, University of Arizona, University of Washington, CNRS, etc.), and keywords & concepts (astrobiology, life, Mars, amino acid, prebiotic chemistry, evolution, RNA) are explored.Azinfar, B., Haddadnia, A., Zirrahi, M., Hassanzadeh, H., Abedi, J., 2018. Phase behaviour of butane/bitumen fractions: Experimental and modeling studies. Fuel 220, 47-59. of butane as a solvent in solvent-aided recovery of bitumen has shown to be promising. In these recovery processes, hot butane or butane and steam mixture is injected into subsurface bitumen reservoirs to dilute the bitumen. Diluted bitumen drains to production well and is produced. The primary steps towards an optimized and successful solvent-aided bitumen recovery method are bitumen characterization and phase behaviour study of solvent/bitumen system. In this work, we develop a generalized equation of state (EoS) to predict the butane solubility in bitumen and heavy oils. Bitumen is fractionated experimentally and the measured data for each fraction is used to tune the EoS. The vacuum distillation is utilized to fractionate bitumen into four cuts. Each bitumen cut is then characterized and the phase behaviour data including solubility, density and viscosity of butane/bitumen cuts are measured at three temperatures of 100, 150, and 186?°C and pressures up to 4?MPa. The proposed generalized thermodynamic model predicts butane solubility in bitumen using results of simulated distillation (SimDist) test to define bitumen components. The developed EoS model is evaluated by comparing the calculated solubility of butane in Athabasca and Cold Lake bitumens with experimental data. The results show that the generalized model is able to predict butane solubility in bitumen without using experimental solubility data to tune the EoS with acceptable accuracy. The density and viscosity of original and butane-saturated bitumen cuts are also correlated. The developed model serves as a substitute for time consuming and expensive solubility measurements. These results find applications in design and optimization of solvent-aided recovery process of bitumen.Babaei, M., Mu, J., Masters, A.J., 2018. Impact of variation in multicomponent diffusion coefficients and salinity in CO2-EOR: A numerical study using molecular dynamics simulation. Journal of Petroleum Science and Engineering 162, 685-696. injection in depleted or partially depleted oil reservoirs entails a three phase flow system governed by physical processes such as molecular diffusion and solubility. Using numerical modelling, the aims of this paper are two-fold. (i) We investigate the impact of variations in the magnitude of diffusion of CO2 into oil on dissolution of CO2 in brine, and quantify the sensitivity of the simulation outputs (recovery factor and amount of CO2 stored in water and oil phases) by use of different sets of diffusion coefficients throughout the simulation based on the variations in the compositions of the fluids. (ii) We investigate whether CO2 dissolution in brine in a water-flooded system will be a competing or limiting factor for enhanced oil recovery by molecular diffusion of CO2 into oil. To this end, we use molecular dynamics (MD) simulation to determine composition-dependent diffusion coefficients for a multicomponent fluid system in a synthetic fractured reservoir that undergoes CO2 injection. In total we consider 5 components interacting in the reservoir model, namely, CO2, CH4, C4H10, C6H14 and C10H22. The fracture-matrix interaction is simplified with the dual-porosity assumption. Our results show that (i) molecular diffusion not only enhances oil recovery but also enhances CO2 dissolution in water. The enhancement, nevertheless, depends on the values of the multicomponent diffusion coefficients and may exhibit an optimal condition for dissolution due to the impact of CO2 diffusion and entrapment into matrix oil. (ii) The amount of CO2 stored in oil is strongly affected by variation in molecular diffusion coefficients (we observe up to %13 difference). (iii) The results show that there is 4% discrepancy between estimates of the recovery factor for simulation cases that are run with different values of diffusion coefficients. Therefore it is important to account for compositions-dependent diffusion coefficients in simulation of CO2-enhanced oil recovery processes.Bae, S.S., Jung, J., Chung, D., Baek, K., 2018. Marinobacterium aestuarii sp. nov., a benzene-degrading marine bacterium isolated from estuary sediment. International Journal of Systematic and Evolutionary Microbiology 68, 651-656. Gram-stain-negative, aerobic, motile, flagellated rod-shaped bacterium, designated ST58-10T, was isolated from an estuarine sediment in the Republic of Korea. The strain was able to degrade benzene. Growth of strain ST58-10T was observed at 4–35?°C (optimum, 20–25?°C), pH 5–9 (optimum, pH 7–8) and 1–8?%?NaCl (optimum, 3?%). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain ST58-10T formed a phyletic lineage within the genus Marinobacterium of the family Oceanospirillaceae . Strain ST58-10T was most closely related to Marinobacterium profundum PAMC 27536T (99.6?%) and Marinobacterium rhizophilum CL-YJ9T (98.3?%), and to other members of the genus Marinobacterium (94.5–91.5?%). However, the mean value estimated by using the Genome-to-Genome Distance Calculator was 50.6±7.4?% with M. profundum PAMC 27536T and 30.9±2.8 with M. rhizophilum CL-YJ9T, respectively. An average nucleotide identity value was 89.0?% with M. profundum PAMC 27536T and 85.6?% with M. rhizophilum CL-YJ9T, respectively. The major fatty acids of strain ST58-10T were summed feature 3 (comprising C16?:?1 ω7c/C16?:?1 ω6c), summed feature 8 (comprising C18?:?1 ?ω7c/C18?:?1 ω6c), C16?:?0 and C10?:?0 3-OH, and contained ubiquinone (Q-8) as the sole isoprenoid quinone. Phosphatidylethanolamine, phosphatidylglycerol, three unidentified aminolipids, an unidentified glycolipid and an unidentified lipid were detected as polar lipids. The DNA G+C?content of strain ST58-10T was 58.78?mol%. On the basis of the phenotypic, chemotaxonomic and molecular properties, strain ST58-10T represents a novel species of the genus Marinobacterium , for which the name Marinobacterium aestuarii sp. nov. is proposed. The type strain is ST58-10T (=KCTC 52193T=NBRC 112103T). The GenBank accession numbers for the 16S rRNA gene sequence and the whole genome of strain ST58-10T are KU886021 and CP015839, respectively.Bai, C., Yu, B., Liu, H., Xie, Z., Han, S., Zhang, L., Ye, R., Ge, J., 2018. The genesis and evolution of carbonate minerals in shale oil formations from Dongying depression, Bohai Bay Basin, China. International Journal of Coal Geology 189, 8-26. oil is attracting increasing attention in the petroleum industry as an essential target of unconventional oil and gas exploration. Recent exploration efforts have indicated that laminar carbonates are closely related to the favorable depositional strata of shale oil. This research focused on inter-bedded layers of laminar carbonates as well as mudstone and shale in the Dongying depression of the Bohai Bay Basin in eastern China, and attempted to reveal the genesis and evolution of the carbonates by means of drill core observations, thin sections, high resolution scanning electron microscopic observations, and fluorometric, cathodoluminescence and geochemical analyses. The results demonstrated that: (1) the carbonates could be categorized into two groups, crystalline carbonates and micritic carbonates; (2) the crystalline carbonates were well crystallized and greenish under fluorescent light; and (3) the micritic carbonates were not well crystallized and had biotic textures. It was discovered that the crystalline carbonates were mainly developed in the shale layer and were formed from the late-filling effects of the diagenetic cracks along the shale fissility planes; shale layers with crystalline carbonates are usually favorable for shale oil reserves. The micritic carbonates were formed from direct deposition controlled by biological effects in the stratified flows of the seasonal lake basins and are unfavorable for shale oil reserves.Bain, P.A., Kumar, A., 2018. In?vitro nuclear receptor inhibition and cytotoxicity of hydraulic fracturing chemicals and their binary mixtures. Chemosphere 198, 565-573. widespread use of hydraulic fracturing (HF) in oil and gas extraction operations has led to concern over environmental risks posed by chemicals used in HF fluids. Here we employed a suite of stable luciferase reporter gene assays to investigate the potential for selected HF chemicals or geogenics to activate or antagonise nuclear receptor signalling. We screened three biocides (bronopol [BP], glutaraldehyde [GA], and tetrakis(hydroxymethyl)phosphonium sulfate [THPS]), a surfactant (2-butoxyethanol), a friction reducer (polyacrylamide), and a coal seam geogenic (o-cresol) for their potential to act as agonists or antagonists of the estrogen receptor, androgen receptor, progesterone receptor (PR), glucocorticoid receptor or peroxisome proliferator-activated receptor gamma (PPARγ). None of the chemicals induced luciferase activity in any of assays used in the study. In antagonistic mode, BP, GA and THPS caused reductions in luciferase activity in the reporter assays at higher concentrations (50–100?μM), while at low concentrations (2–10?μM) GA and THPS enhanced luciferase activity in some assays relative to controls. None of the other tested chemicals exhibited antagonism in the selected assays. In most cases, altered receptor signalling only occurred at concentrations exhibiting cytotoxicity. However, PPARγ activity, and to a lesser extent PR activity, were inhibited by THPS at sub-cytotoxic concentrations. The majority of binary combinations tested exhibited significantly less-than-additive cytotoxicity, and none of the combinations exhibited synergistic cytotoxicity. In summary, the results of the present study indicate that the selected chemicals are not likely to function as direct agonists of the nuclear receptors tested, and only one chemical, THPS was an apparent partial antagonist of two nuclear receptors.Bakshi, T., Prusty, B.K., Pathak, K., Pal, S.K., 2018. Pore characteristics of Damodar Valley shale and their effect on gas storage potential. Journal of Petroleum Science and Engineering 162, 725-735. current global interest in fine grained sedimentary shale rock is driven by its ability to store gas in the pore spaces in them. The current study focuses on the understanding of the gas storage capacity of less explored Damodar Valley shales of India, in light of pore characteristics of organic matter and clay minerals. In this study, four samples were collected from different parts of Damodar valley basin and their geochemical composition, pore structure and adsorption capacity were investigated by XRD studies, rock-eval analyses, low-pressure N2-CO2 adsorption analyses and high-pressure methane adsorption experiment. The samples were also studied to know their hydrocarbon potential. The relationship between mineralogy, organic matter, and pore-structure was analyzed and finally, their effect on methane sorption capacity was discussed. The shale samples are found to be clay rich. The average clay content of the shale samples is 50.69% and average quartz content is 31.65%. Presence of excellent TOC content (4.8%–37.36%) with a predominance of type III organic matter and Tmax varying from 440 °C to 465 °C suggests a very good to excellent hydrocarbon generation potential in all the samples. The correlation between the TOC and VL was found to be positive indicating a positive influence of organic matter on methane sorption capacity of the studied samples. However, a lack of correlation between total clay and CH4-VL indicates that the role of clay minerals on methane sorption behavior of these shales are inconclusive. A positive correlation between CO2 micropore volume, CH4-VL and TOC suggest microporous nature of organic matter within the shale samples and their positive control on methane sorption potential. The negative correlation of clay mineral with CO2 micropore volume suggests a lack of microporosity in the clay minerals of the collected shale samples. It was also observed that thermally mature shale samples have higher micropore volume and surface area, and are prone to higher methane sorption capacity compared to that of less mature shales.Balch, W.M., Bowler, B.C., Drapeau, D.T., Lubelczyk, L.C., Lyczkowski, E., 2018. Vertical distributions of coccolithophores, PIC, POC, biogenic silica, and chlorophyll a throughout the global ocean. Global Biogeochemical Cycles 32, 2-17. are a critical component of global biogeochemistry, export fluxes, and seawater optical properties. We derive globally significant relationships to estimate integrated coccolithophore and coccolith concentrations as well as integrated concentrations of particulate inorganic carbon (PIC) from their respective surface concentration. We also examine surface versus integral relationships for other biogeochemical variables contributed by all phytoplankton (e.g., chlorophyll a and particulate organic carbon) or diatoms (biogenic silica). Integrals are calculated using both 100?m integrals and euphotic zone integrals (depth of 1% surface photosynthetically available radiation). Surface concentrations are parameterized in either volumetric units (e.g., m?3) or values integrated over the top optical depth. Various relationships between surface concentrations and integrated values demonstrate that when surface concentrations are above a specific threshold, the vertical distribution of the property is biased to the surface layer, and when surface concentrations are below a specific threshold, the vertical distributions of the properties are biased to subsurface maxima. Results also show a highly predictable decrease in explained-variance as vertical distributions become more vertically heterogeneous. These relationships have fundamental utility for extrapolating surface ocean color remote sensing measurements to 100?m depth or to the base of the euphotic zone, well beyond the depths of detection for passive ocean color remote sensors. Greatest integrated concentrations of PIC, coccoliths, and coccolithophores are found when there is moderate stratification at the base of the euphotic zone.Plain Language Summary. We use a global shipboard data set to describe the vertical distributions of coccolithophores (marine phytoplankton that produce microscopic calcium carbonate scales). These plants are responsible for over half of all the suspended calcium carbonate in the ocean, they can cause major increases in water reflectance in blooms spanning entire ocean basins, and they provide ballast to organic matter to the deep sea and thus are strong drivers of the ocean's biological carbon pump (responsible for sequestering carbon in the deep sea). This paper describes global relationships that relate the surface concentrations of coccolithophores and their particulate inorganic carbon (as observed by satellite) to concentrations found over the upper 100 m of the ocean or the entire euphotic zone. These predictions function from highest productivity waters to the lowest productivity, “biological deserts” in the sea. We also include predictive relationships for biogeochemical variables related to other phytoplankton groups (e.g., diatoms) as well as more generic indicators of phytoplankton (e.g., chlorophyll and particulate organic carbon). The results provide new oceanographic insights into the ecology and biogeochemistry of these microalgal groups.Baltrons, O., López-Mesas, M., Vilaseca, M., Gutiérrez-Bouzán, C., Le Derf, F., Portet-Koltalo, F., Palet, C., 2018. Influence of a mixture of metals on PAHs biodegradation processes in soils. Science of The Total Environment 628–629, 150-158. order to assess the effect of mixed pollutants, the influence of different concentration levels of a mixture of metals (Cr, Co, Pb, Mn, Ni, Cu, Zn) on the biodegradation of some PAHs (phenanthrene, fluoranthene, pyrene, benzo[b]fluoranthene and benzo[a]pyrene) in soil samples was evaluated. To do so, groups of microcosms of a natural soil from the region of Sabadell (Barcelona, Spain) were prepared as a reproduction of the native environment at laboratory scale, under controlled conditions. Mixtures of PAHs and metals were carefully selected, according to soil characterization and microbiological growth preliminary assays, and were added to microcosms. These microcosms were analyzed at various times, along two months, to obtain PAHs dissipation time-courses. A first-order kinetic modelling allowed obtaining different rate constants and DT50 values as a function of the metal levels introduced in microcosms. As a general observation, the higher the concentration of metals, the lower the biodegradation of PAHs of 3–4 rings (phenanthrene, fluoranthene and pyrene). On the other hand, no important effect on the biodegradation of higher molecular weight PAHs (benzo[b]fluoranthene and benzo[a]pyrene) was observed at the different concentration levels of metals tested.Bandowe, B.A.M., Bigalke, M., Kobza, J., Wilcke, W., 2018. Sources and fate of polycyclic aromatic compounds (PAHs, oxygenated PAHs and azaarenes) in forest soil profiles opposite of an aluminium plant. Science of The Total Environment 630, 83-95. is known about oxygenated polycyclic aromatic hydrocarbons (OPAHs) and azaarenes (AZAs) in forest soils. We sampled all horizons of forest soils from five locations at increasing distances from an Al plant in Slovakia, and determined their polycyclic aromatic compound (PACs) concentrations. The ∑29PAHs concentrations were highest in the Oa and lowest in the Oi horizon, while the ∑14OPAHs and ∑4AZAs concentrations did not show a consistent vertical distribution among the organic horizons. The concentration ratios of PAHs and OPAHs between deeper O horizons and their overlying horizon (enrichment factors) were positively correlated with the octanol-water partition coefficients (KOW) at several locations. This is attributed to the slower degradation of the more hydrophobic PACs during organic matter decomposition. PACs concentrations decreased from the organic layer to the mineral horizons. The concentrations of ∑29PAHs (2400–17,000?ng?g?1), ∑14OPAHs (430–2900?ng?g?1) and ∑4AZAs (27–280?ng?g?1) in the mineral A horizon generally decreased with increasing distance from the Al plant. In the A horizons, the concentrations of ∑29PAHs were correlated with those of ∑14OPAHs (r?=?0.95, p?=?0.02) and ∑4AZAs (r?=?0.93, p?=?0.02) suggesting that bioturbation was the main transport process of PACs from the organic layer into the mineral soil. At each location, the concentrations of PACs generally decreased with increasing depth of the mineral soil. Enrichment factors of PAHs in the mineral horizons were not correlated with KOW, pointing at colloid-assisted transport and bioturbation. The enrichment factors of OPAHs (in mineral horizons) at a site were negatively correlated with their KOW values indicating that these compounds were leached in dissolved form. Compared to a study 13?years before, the concentrations of PAHs had decreased in the O horizons but increased in the A and B horizons because of soil-internal redistribution after emissions had been reduced.Barnes, R.T., Butman, D.E., Wilson, H.F., Raymond, P.A., 2018. Riverine export of aged carbon driven by flow path depth and residence time. Environmental Science & Technology 52, 1028-1035. flux of terrestrial C to rivers has increased relative to preindustrial levels, a fraction of which is aged dissolved organic C (DOC). In rivers, C is stored in sediments, exported to the ocean, or (bio)chemically processed and released as CO2. Disturbance changes land cover and hydrology, shifting potential sources and processing of DOC. To investigate the likely sources of aged DOC, we analyzed radiocarbon ages, chemical, and spectral properties of DOC and major ions from 19 rivers draining the coterminous U.S. and Arctic. DOC optics indicated that the majority is exported as aromatic, high molecular weight, modern molecules while aged DOC tended to consist of smaller, microbial degradation products. Aged DOC exports, observed regularly in arid basins and during base flow in arctic rivers, are associated with higher proportion of mineral weathering products, suggesting deeper flows paths. These patterns also indicate potential for production of microbial byproducts as DOC ages in soil and water with longer periods of time between production and transport. Thus, changes in hydrology associated with landscape alteration (e.g., tilling or shifting climates) that can result in deeper flow paths or longer residence times will likely lead to a greater proportion of aged carbon in riverine exports.Barrilero, R., Gil, M., Amigó, N., Dias, C.B., Wood, L.G., Garg, M.L., Ribalta, J., Heras, M., Vinaixa, M., Correig, X., 2018. LipSpin: A new bioinformatics tool for quantitative 1H NMR lipid profiling. Analytical Chemistry 90, 2031-2040. structural similarity among lipid species and the low sensitivity and spectral resolution of nuclear magnetic resonance (NMR) have traditionally hampered the routine use of 1H NMR lipid profiling of complex biological samples in metabolomics, which remains mostly manual and lacks freely available bioinformatics tools. However, 1H NMR lipid profiling provides fast quantitative screening of major lipid classes (fatty acids, glycerolipids, phospholipids, and sterols) and some individual species and has been used in several clinical and nutritional studies, leading to improved risk prediction models. In this Article, we present LipSpin, a free and open-source bioinformatics tool for quantitative 1H NMR lipid profiling. LipSpin implements a constrained line shape fitting algorithm based on voigt profiles and spectral templates from spectra of lipid standards, which automates the analysis of severely overlapped spectral regions and lipid signals with complex coupling patterns. LipSpin provides the most detailed quantification of fatty acid families and choline phospholipids in serum lipid samples by 1H NMR to date. Moreover, analytical and clinical results using LipSpin quantifications conform with other techniques commonly used for lipid analysis.Barupal, D.K., Fan, S., Fiehn, O., 2018. Integrating bioinformatics approaches for a comprehensive interpretation of metabolomics datasets. Current Opinion in Biotechnology 54, 1-9. to high quality metabolomics data has become a routine component for biological studies. However, interpreting those datasets in biological contexts remains a challenge, especially because many identified metabolites are not found in biochemical pathway databases. Starting from statistical analyses, a range of new tools are available, including metabolite set enrichment analysis, pathway and network visualization, pathway prediction, biochemical databases and text mining. Integrating these approaches into comprehensive and unbiased interpretations must carefully consider both caveats of the metabolomics dataset itself as well as the structure and properties of the biological study design. Special considerations need to be taken when adopting approaches from genomics for use in metabolomics. R and Python programming language are enabling an easier exchange of diverse tools to deploy integrated workflows. This review summarizes the key ideas and latest developments in regards to these approaches.Battandier, M., Bonal, L., Quirico, E., Beck, P., Engrand, C., Duprat, J., Dartois, E., 2018. Characterization of the organic matter and hydration state of Antarctic micrometeorites: A reservoir distinct from carbonaceous chondrites. Icarus 306, 74-93. work presents a multi-analysis on 35 Antarctic micrometeorites (AMMs) (Concordia collection 2006) by coupled Raman and Infrared (IR) spectroscopies, in comparison with samples from type 1 and 2 carbonaceous CM, CR and CI chondrites. We identified the Raman G- and D-bands revealing the presence of polyaromatic carbonaceous material on raw particles in a subset of 16 particles. Thirteen AMMs (10 Fg?+?1 Fg-Sc?+?1 Sc) were selected from this first subset, and analyzed by infrared microscopy along with 4 AMMs (2 Fg?+?1 Fg-Sc?+?1 Sc) from a previous study by Dobrica et al. (2011). These analyses showed that scoriaceous, fine-grained scoriaceous and part of the fine-grained AMMs are not hydrated, with a weak abundance of carbonaceous matter. According to the Raman criterion defined by Dobrica et al. (2011), hydrous AMMs do not show structural modifications induced by heating through the atmospheric entry. In several hydrous AMMs, the carbonaceous matter abundance is found larger than in Orgueil (CI), Murchison (CM) and QUE 99177 (CR) chondrites and their mineral content exhibit differences reflected by the structure of the silicate 10??m band. These observations suggest that part of the AMMs originates from one, or several, distinct parent bodies with respect to primitive carbonaceous chondrites. Each hydrous Fg-AMMS displays higher CH2/CH3 ratio and a smaller carbonyl abundance than chondrites, which point toward a mild processing during atmospheric entry, possibly oxidation, which did not modify the carbon backbone and therefore do not induce differences in Raman spectroscopy.Bazyari, A., Jamialahmadi, M., Soltani Soulgani, B., Zeinijahromi, A., 2018. Evaluation of enhanced oil recovery from clay-rich sandstone formations. Petroleum Science and Technology 36, 405-410. the last few years, there has been a growing interest in smart water (SW) flooding as economically and environmentally friendly method to Enhanced Oil Recovery (EOR) in sandstone and carbonated reservoirs. Formation damage especially fines migration and clay swelling by lowering salinity and changing the ionic environment, causes the significant decrease in permeability of the sandstone reservoirs. In this study, an experimental study has been undertaken to illuminate the effect of formation damage during smart water injection as the function of clay types. The state of the art procedure has been established in direction of sandpack construction containing favorable clay content. Injection of smart water was performed in sandpacks with different clay types (montmorillonite and kaolinite). The results show that the presence of montmorillonite augments formation damage and enhances oil recovery. Analyzing Interfacial Tension (IFT) experimental data showed that interaction of oil/SW had no great influence on increasing oil recovery. The results have been achieved based on extensive experiments including Differential Pressure (DP) measurements, Zeta potential, and Recovery Factor (RF). Two mechanisms were proposed to interpret permeability reduction and amount of oil produced values which are clay swelling, and detachment/re-attachment for montmorillonite and kaolinite, respectively.Bechst?dt, T., J?ger, H., Rittersbacher, A., Schweisfurth, B., Spence, G., Werner, G., Boni, M., 2018. The Cryogenian Ghaub Formation of Namibia – New insights into Neoproterozoic glaciations. Earth-Science Reviews 177, 678-714. Neoproterozoic Cryogenian (‘Marinoan’) Ghaub Formation of northwestern Namibia represents an important founding pillar of the Snowball Earth hypothesis and its derivative, the Panglacial Earth hypothesis. These hypotheses assume oceans and continents covered by thick ice, even in the tropics, which caused a very distinct drop in eustatic sea-level. Over time, strongly increased CO2 contents of the atmosphere led to sudden ice melting, very substantial sea-level rise, and strong weathering on the continents associated with the deposition of cap carbonates in the newly ice-free oceans. The ongoing controversy about Snowball-type glaciations in Namibia and elsewhere is reviewed, and other hypotheses (Slushball Earth, Waterbelt Earth, Jormungand state of the Earth, Thin Ice state of the Earth, Zipper-Rift Earth, High-Obliquity Earth) are discussed. We prefer the term ‘Waterbelt Earth’ instead of the originally proposed ‘Waterbelt state’ because of the clearer contrast with ‘Snowball Earth’.Because a great deal of information related to Cryogenian glaciations comes from the Ghaub Formation of northwestern Namibia, these hypotheses should be tested independently based on a time-equivalent depositional system. This analogue was found in the carbonate-dominated successions of the Otavi Mountainland (OML), northeastern Namibia, and is highly comparable with the successions in the well-investigated northwest of the country. An extreme eustatic sea-level drop caused by a global glaciation of oceans and continents and imposed on a carbonate platform or ramp such as the one in the OML would have led either to glacial cover or widespread subaerial exposure and extensive erosion, including deeply incised valleys. The presence of such features would strongly support the Snowball Earth hypotheses if tectonic effects did not play a major role. During the postglacial transgression, distinct reworking of the carbonate platform/ramp surface would have occurred, leaving behind lag deposits, as well as infills of incised valleys with fluvial, reworked glacial, and marine deposits. The main objective of our research was to weigh and investigate the strengths and weaknesses of the proposed Snowball Earth model of glacially induced large-amplitude sea-level changes during Ghaub time, and to compare different models to obtain a rough estimate of the amount of glaciation.The study area in the OML includes two different, age-equivalent facies realms: platform sedimentation in the Southern area without diamictites, and slope deposits, including Ghaub diamictites, in the Northern area. The southern, continuously shallow-marine area shows a shallowing-upward succession from the pre-glacial lower Auros Formation, often varve-like laminated shales formed below wave base, to metre-high columnar stromatolites and microbial mat-related carbonates with intervals of vertical tubes (degassing features) of the upper Auros Formation, overlain by cap carbonates of the Maieberg Formation. The columnar stromatolites and the microbial tubestone lithotypes were clearly deposited in the euphotic zone. Indications for tidal conditions or subaerial exposure were not recorded in this platform succession without unconformities. Neither dropstones, nor incised channels, nor transgressive lag deposits were observed. The facies changes from below storm wave base to the photic zone and finally a shallow subtidal zone is explained by a prolonged, modest sea-level fall, partly counterbalanced by subsidence, followed by a slow transgression.In contrast, coarse-grained sedimentary rocks (e.g., oolites, debrites) characterise the time-equivalent successions in the Northern area. Starting with laminated shales at the base, similar to the Southern area, the overlying redeposited oolites and breccias of the Auros Formation show distinct lateral and vertical inhomogeneities and thickness changes, which indicate long-lasting synsedimentary tectonism. The same phenomenon is observed in the overlying diamictites of the Ghaub Formation. Their variable clast content indicates erosion of a strongly uplifted local source area formerly covered by a thick carbonate succession, which was downstripped to the crystalline basement. The prograding diamictite succession with repeatedly intercalated silt-stringers is interpreted as periglacial debris flows into a marine environment. Sparse striated clasts in the diamictites and very rare dropstones (much less common than in northwestern Namibia) are indicators of glaciations somewhere in the area. However, compared with other glacial sequences, e.g. Quaternary periglacial sediments at the forefront of continental ice, dropstones and striated clasts would be expected to be much more common and more uniformly distributed if the entire area was covered by melting continental ice, as proposed in the Snowball/Panglacial Earth scenario. In the Southern area, dropstones would be expected to occur on the flooded platforms/ramps as well, even when diamictites are absent.Both the relatively moderate sea-level change and the less common, irregular distribution of locally concentrated glacial rainouts provide strong evidence against the presence of a thick, laterally continuous ice cover over oceans and continents extending to equatorial areas. The oceans possibly corresponded to the scenario of a Waterbelt Earth or High-Obliquity Earth; evidence of open oceanic water exists, which would have enabled the continued evolution of biota. Glacial ice was present on tropical continents, but its occurrences may have been regional in patches, sourced from mountainous areas, and ice streams would have reached the oceans only locally, unrelated to a thick continental ice cover.Belt, S.T., Brown, T.A., Smik, L., Assmy, P., Mundy, C.J., 2018. Sterol identification in floating Arctic sea ice algal aggregates and the Antarctic sea ice diatom Berkeleya adeliensis. Organic Geochemistry 118, 1-3. number of common sterols were identified in sea ice diatoms from the Arctic and the Antarctic. The main sterols in floating sea ice algal aggregates collected from Resolute Passage (Canadian Arctic) and Nansen Basin (North Svalbard) in 2012 were 22E-dehydrocholesterol, cholesterol, epi-brassicasterol, 24-methylenecholesterol and 24-ethylcholesterol, although the distribution varied between the two locations, likely reflecting compositional differences in diatom taxa. The three major sterols in cells of Berkeleya adeliensis picked from a melted sea ice core collected from Ryder Bay in the Antarctic Peninsula in 2014, were 24-ethylcholesterol, cholesterol and 22E-dehydrocholesterol. We suggest that certain sea ice diatoms may thus contribute to the sedimentary budget of common sterols in seasonally sea ice-covered locations following ice melt.Benca, J.P., Duijnstee, I.A.P., Looy, C.V., 2018. UV-B–induced forest sterility: Implications of ozone shield failure in Earth’s largest extinction. Science Advances 4, Article e1700618. Siberian Trap volcanism is considered a primary driver of the largest extinction in Earth history, the end-Permian crisis, the relationship between these events remains unclear. However, malformations in fossilized gymnosperm pollen from the extinction interval suggest biological stress coinciding with pulsed forest decline. These grains are hypothesized to have been caused by enhanced ultraviolet-B (UV-B) irradiation from volcanism-induced ozone shield deterioration. We tested this proposed mechanism by observing the effects of inferred end-Permian UV-B regimes on pollen development and reproductive success in living conifers. We find that pollen malformation frequencies increase fivefold under high UV-B intensities. Surprisingly, all trees survived but were sterilized under enhanced UV-B. These results support the hypothesis that heightened UV-B stress could have contributed not only to pollen malformation production but also to deforestation during Permian-Triassic crisis intervals. By reducing the fertility of several widespread gymnosperm lineages, pulsed ozone shield weakening could have induced repeated terrestrial biosphere destabilization and food web collapse without exerting a direct “kill” mechanism on land plants or animals. These findings challenge the paradigm that mass extinctions require kill mechanisms and suggest that modern conifer forests may be considerably more vulnerable to anthropogenic ozone layer depletion than expected.Beňo, E., Góra, R., Hutta, M., 2018. Development of a precolumn derivatization HPLC method with diode-array detection for the determination of amino sugars in peat and soil humic acids. Journal of Separation Science 41, 814-821. work is focused on the development of a high-performance liquid chromatography method with diode-array detection for the separation and quantitation of the three most abundant amino sugars; d-glucosamine, d-galactosamine, and d-mannosamine. The high-performance liquid chromatography separation was carried out by reversed-phase chromatography on Chromolith Performance RP-18e monolithic column after acid hydrolysis (5 M HCl) and precolumn derivatization of samples using diethyl ethoxymethylenemalonate. Gradient elution and a mobile phase composed of ammonium formate buffer solution (10 mmol/L, pH 3.60) and methanol with flow rate of 1.0 mL/min were used. The monitoring wavelength was set at 280 nm. The limits of detection and quantitation for analytes ranged from 0.017 to 0.122 mg/L and from 0.057 to 0.407 mg/L, respectively. The proposed method was successfully applied for the determination of amino sugars in samples of humic acids isolated from different soils and peat.Bercovici, S.K., McNichol, A.P., Xu, L., Hansell, D.A., 2018. Radiocarbon content of dissolved organic carbon in the South Indian Ocean. Geophysical Research Letters 45, 872-879. report four profiles of the radiocarbon content of dissolved organic carbon (DOC) spanning the South Indian Ocean (SIO), ranging from the Polar Front (56°S) to the subtropics (29°S). Surface waters held mean DOC Δ14C values of ?426 ± 6‰ (~4,400 14C years) at the Polar Front and DOC Δ14C values of ?252 ± 22‰ (~2,000 14C years) in the subtropics. At depth, Circumpolar Deep Waters held DOC Δ14C values of ?491 ± 13‰ (~5,400 years), while values in Indian Deep Water were more depleted, holding DOC Δ14C values of ?503 ± 8‰ (~5,600 14C years). High-salinity North Atlantic Deep Water intruding into the deep SIO had a distinctly less depleted DOC Δ14C value of ?481 ± 8‰ (~5,100 14C years). We use multiple linear regression to assess the dynamics of DOC Δ14C values in the deep Indian Ocean, finding that their distribution is characteristic of water masses in that region.Berliner, A.J., Mochizuki, T., Stedman, K.M., 2018. Astrovirology: Viruses at large in the universe. Astrobiology 18, 207-223. are the most abundant biological entities on modern Earth. They are highly diverse both in structure and genomic sequence, play critical roles in evolution, strongly influence terran biogeochemistry, and are believed to have played important roles in the origin and evolution of life. However, there is yet very little focus on viruses in astrobiology. Viruses arguably have coexisted with cellular life-forms since the earliest stages of life, may have been directly involved therein, and have profoundly influenced cellular evolution. Viruses are the only entities on modern Earth to use either RNA or DNA in both single- and double-stranded forms for their genetic material and thus may provide a model for the putative RNA-protein world. With this review, we hope to inspire integration of virus research into astrobiology and also point out pressing unanswered questions in astrovirology, particularly regarding the detection of virus biosignatures and whether viruses could be spread extraterrestrially. We present basic virology principles, an inclusive definition of viruses, review current virology research pertinent to astrobiology, and propose ideas for future astrovirology research foci. Birch, H., Hammersh?j, R., Mayer, P., 2018. Determining biodegradation kinetics of hydrocarbons at low concentrations – covering 5 and 9 orders of magnitude of Kow and Kaw. Environmental Science & Technology 52, 2143-2151. partitioning based experimental platform was developed and applied to determine primary biodegradation kinetics of 53 hydrocarbons at ng/L - ?g/L concentrations covering C8-C20, 11 structural classes and several orders of magnitude in hydrophobicity and volatility: (1) Passive dosing from a loaded silicone donor was used to set the concentration of each hydrocarbon in mixture stock solutions, (2) these solutions were combined with environmental water samples in gas tight auto sampler vials for 1 to 100 days incubation and (3) automated Solid Phase MicroExtraction (SPME) coupled to GC-MS was applied directly on these test systems for measuring primary biodegradation relative to abiotic controls. First order biodegradation kinetics were obtained for 40 hydrocarbons in activated sludge filtrate, 18 in seawater and 21 in lake water. Water phase half-lives in seawater and lake water were poorly related to hydrophobicity and volatility but were, with a few exceptions, within a factor of 10 or shorter than BioHCwin predictions. The most persistent hydrocarbons, 1,1,4,4,6-pentamethyldecalin, perhydropyrene, 1,2,3,6,7,8-hexahydropyrene and 2,2,4,4,6,8,8-heptamethylnonane showed limited or inconsistent degradation in all three environmental media. This biodegradation approach can cover a large chemical space at low substrate concentrations, which makes it highly suited for optimizing predictive models for environmental biodegradation.Blach, T., Radlinski, A.P., Edwards, D.S., Boreham, C.J., Rehm, C., de Campo, L., Gilbert, E.P., 2018. Fingerprint of hydrocarbon generation in the southern Georgina Basin, Australia, revealed by small angle neutron scattering. International Journal of Coal Geology 186, 135-144. angle neutron scattering (SANS) and ultra-small angle neutron scattering (USANS) are used to directly detect the processes of hydrocarbon generation in the 10 nm to 10 μm size pores in Middle Cambrian carbonate and siliciclastic rocks which contain no land-plant material suitable for conventional maturity determination by vitrinite reflectance. The method takes advantage of the pore-size-specific variation of neutron scattering contrast between the solid rock matrix and pore-space content with depth, which is caused by thermal maturation of organic matter through the oil and gas generation windows. SANS and USANS measurements were performed on bedding plane-orientated core slices, extracted from a series of 10 to 12 depth intervals for three wells CKAD0001, MacIntyre 1 and Baldwin 1, in the southern Georgina Basin, central Australia. The depth intervals, intersecting the organic-rich basal ‘hot’ shales of the middle Cambrian Arthur Creek Formation, were selected based on Rock-Eval pyrolysis data. SANS and USANS results indicate that oil generation has occurred in the past in nanometer-sized pores in rocks that are now at depths of around 538.4 m in CKAD0001 and 799.3 m in MacIntyre 1. Furthermore, in the CKAD0001 well, the oil-wet pores extend into the larger pore-size range (at least up to 10 μm) due to the efficient expulsion of oil. At around 880 m in Baldwin 1, the influence of pyrobitumen reverts pore space from gas wet to oil wet. These hydrocarbons have remained in situ since the Devonian when the Neoproterozoic to Paleozoic section was exhumed in the Alice Springs Orogeny and subsequently eroded, preserving only remnants of the once extensive basin sediments.Blumberg, L.M., 2018. Flow optimization in one-dimensional and comprehensive two-dimensional gas chromatography. Journal of Chromatography A 1536, 27-38. considerations of optimal flow in a GC column under different conditions are outlined from a single perspective, and numerical recommendations are provided. The optimal flow rate in a temperature programmed column is about 30% lower than its isothermal counterpart in the same column with the same carrier gas. A simplified calculation of recommended optimal or near optimal flow rate in a single column under different conditions is summarized in a single equation.In GC?×?GC, the primary column operates under temperature-programmed conditions while each secondary run is essentially isothermal. As a result, their flow optimization requirements are different. The complementary IDs (internal diameters) corresponding to equal optimal flow rates in both GC?×?GC columns should relate as 2d?=?0.7?·1d. Typical complementary ID pairs are tabulated. If choosing the complementary IDs is not an option, several ways to reconcile the difference in their optimal flow rates are considered. The most typical cases of the column mismatch are identified and their boundary conditions are formulated. The effect of the flow reconciliation in these column pairs on the performance of GC?×?GC analysis is evaluated.Boast, A.P., Weyrich, L.S., Wood, J.R., Metcalf, J.L., Knight, R., Cooper, A., 2018. Coprolites reveal ecological interactions lost with the extinction of New Zealand birds. Proceedings of the National Academy of Sciences 115, 1546.: Ancient DNA metabarcoding of coprolites (ancient dung) has greatly improved our ability to investigate the behavior and ecology of extinct species. We use coprolites from extinct New Zealand birds to show how this approach can reveal aspects of dietary behavior, such as the consumption of ectomycorrhizal fungi, and both the distribution and coextinction of parasites. We show how this approach can identify lost ecological interactions, which have key implications for understanding, conserving, and restoring currently threatened ecosystems.Abstract: Over the past 50,000 y, biotic extinctions and declines have left a legacy of vacant niches and broken ecological interactions across global terrestrial ecosystems. Reconstructing the natural, unmodified ecosystems that preceded these events relies on high-resolution analyses of paleoecological deposits. Coprolites are a source of uniquely detailed information about trophic interactions and the behaviors, gut parasite communities, and microbiotas of prehistoric animal species. Such insights are critical for understanding the legacy effects of extinctions on ecosystems, and can help guide contemporary conservation and ecosystem restoration efforts. Here we use high-throughput sequencing (HTS) of ancient eukaryotic DNA from coprolites to reconstruct aspects of the biology and ecology of four species of extinct moa and the critically endangered kakapo parrot from New Zealand (NZ). Importantly, we provide evidence that moa and prehistoric kakapo consumed ectomycorrhizal fungi, suggesting these birds played a role in dispersing fungi that are key to NZ’s natural forest ecosystems. We also provide the first DNA-based evidence that moa frequently supplemented their broad diets with ferns and mosses. Finally, we also find parasite taxa that provide insight into moa behavior, and present data supporting the hypothesis of coextinction between moa and several parasite species. Our study demonstrates that HTS sequencing of coprolites provides a powerful tool for resolving key aspects of ancient ecosystems and may rapidly provide information not obtainable by conventional paleoecological techniques, such as fossil analyses.Bobrovskiy, I., Hope, J.M., Krasnova, A., Ivantsov, A., Brocks, J.J., 2018. Molecular fossils from organically preserved Ediacara biota reveal cyanobacterial origin for Beltanelliformis. Nature Ecology & Evolution 2, 437-440. Ediacara biota (~575–541 million years ago) mark the emergence of large, complex organisms in the palaeontological record, preluding the radiation of modern animal phyla. However, their phylogenetic relationships, even at the domain level, remain controversial. We report the discovery of molecular fossils from organically preserved specimens of Beltanelliformis, demonstrating that they represent large spherical colonies of cyanobacteria. The conservation of molecular remains in organically preserved Ediacaran organisms opens a new path for unravelling the natures of the Ediacara biota.Bock, N., Van Wambeke, F., Dion, M., Duhamel, S., 2018. Microbial community structure in the Western Tropical South Pacific. Biogeosciences Discussions 2018, 1-24. for 40 percent of the earth's surface, oligotrophic regions play an important role in global biogeochemical cycles, with microbial communities in these areas representing an important term in global carbon budgets. While the general structure of microbial communities has been well documented in the global ocean, some remote regions such as the Western Tropical South Pacific (WTSP), remain fundamentally unexplored. Moreover, the biotic and abiotic factors constraining microbial abundances and distribution remain not-well resolved. In this study, we quantified the spatial (vertical and horizontal) distribution of major microbial plankton groups along a transect through the WTSP during the austral summer of 2015, capturing important autotrophic and heterotrophic assemblages including cytometrically determined abundances of non-pigmented protists (also called flagellates). Using environmental parameters (e.g. nutrients and light availability) as well as statistical analyses, we estimated the role of bottom-up and top-down controls in constraining the structure of the WTSP microbial communities in biogeochemically distinct regions. At the most general level, we found a typical tropical structure, characterized by high abundances of Prochlorococcus at the surface, a clear deep chlorophyll maximum at all sampling sites, and a deep nitracline. Despite their relatively low abundances, picophytoeukaryotes (PPE) accounted for up to half of depth-integrated phytoplankton biomass in the lower euphotic zone. While present at all stations, Synechococcus accounted for only 2?% and 4?% of total phytoplankton abundance and biomass, respectively. Our results show that the microbial community structure of the WTSP is typical of highly stratified regions, and underline the significant contribution to total biomass by PPE populations. Strong relationships between N2 fixation rates and plankton abundances demonstrate the central role of N2 fixation in regulating ecosystem processes in the WTSP, while comparative analyses of abundance data suggest microbial community structure to be increasingly regulated by bottom-up processes under nutrient limitation, possibly in response to shifts in abundances of high nucleic acid bacteria (HNA).Bogard, M.J., Butman, D.E., 2018. No blast from the past. Nature Climate Change 8, 99-100. of Arctic soils liberates ancient organic carbon and can facilitate massive greenhouse gas emissions from adjacent aquatic ecosystems. Research now shows that Arctic lakes are generally not releasing very much ancient carbon to the atmosphere.Permafrost soils store roughly double the amount of carbon (C) contained in the atmosphere1. Climate-driven warming and wetting is thawing permafrost, increasing ancient organic C availability for microbial decomposition2. Some lakes have been shown to play an active role in this carbon–climate feedback through increased emissions of carbon dioxide (CO2) and methane (CH4) that are fuelled by the decomposition of ancient soil C (ref. 3). However, the generality of this phenomenon across the broader Arctic landscape is not yet clear. Writing in Nature Climate Change, Elder and colleagues present evidence that many Arctic Alaskan lakes are currently recycling relatively young C to the atmosphere, with little connection to ancient C pools4.The Arctic landscape is dotted with millions of lakes5. These lakes re-mineralize previously fixed organic materials to CO2 and CH4 (Fig. 1), forming an important link between the biosphere and the atmosphere that is amplified by the high lake areal coverage of the Arctic landsape6,7. This loop of C recycling in lakes is not static. Dramatic Arctic warming (double the global average rate of change8) has promoted thawing and lake expansion in some ice-rich and C-rich silt (Yedoma) landscapes, leading to increased processing of ancient C and greater lake emissions, especially of CH4 (ref. 3). Yet the Arctic landscape is extremely heterogeneous. Soil C and ice content can vary dramatically1 and now, with an extensive survey of Arctic Alaskan lakes, Elder and colleagues deepen our understanding of how different landscapes shape lake C emissions, and our understanding of lake connections to both modern and ancient terrestrial C pools.The proportion of lake GHG emissions that escape to the atmosphere as CO2 versus CH4 impacts global warming potential, because CH4 has a 34-fold greater atmospheric warming effect than CO2 on a per-mass basis over a 100-year timeframe8. Surprisingly, the diverse group of lakes studied by Elder and co-authors emitted CO2 almost exclusively, with little release of CH4 (Fig. 1). It therefore appears that the generalized warming potential of most Arctic lakes may be weaker than from CH4-rich lakes in Yedoma regions (for example, ref. 3). These new and comprehensive data help to refine our understanding of pan-Arctic carbon cycling, providing important context to guide future efforts to upscale lake C emissions to the entire polar region.The contribution of Arctic lakes to the global C cycle depends not only on the dominant pathway of C emissions, but also on the extent to which they facilitate the transfer of ancient permafrost C out of storage and into the actively cycling C pool. The extensive efforts to radio-date CO2 and CH4 by Elder et al. provide strong evidence that most Arctic lake emissions are fuelled by organic materials fixed within decades to centuries, with little input of ancient permafrost C stored for dozens of millennia (Fig. 1). An important caveat to this conclusion, however, is that Elder and co-authors identified a far greater variability in C ages across different lake-basin geologies than was evident through time within individual lakes. As the first to include this degree of landscape variability in their Arctic lake C sampling design, this observation is important, because it provides information to help pinpoint the Arctic landscapes where lakes are most active in processing of ancient C.The data of Elder et al. do not distinguish the fraction of Arctic lake C emissions supported by soil or groundwater gas inputs6, or re-mineralization of terrestrial versus lake-derived organic matter (Fig. 1). Therefore, it remains difficult to assess to what extent Arctic lakes are actively consuming terrestrial organic materials and offsetting the terrestrial C sink. This outstanding problem reinforces the need to better couple terrestrial and aquatic carbon processing through empirical field research6,9.The warming potential ascribed to Arctic lakes (Fig. 1) will undoubtedly be further refined in the future. Emissions pathways not accounted for by Elder and co-authors (including bubble-mediated and plant-mediated fluxes) would increase the magnitude of CH4 emissions to an unknown degree. At the same time, inclusion of the permanent burial of C in Arctic lake sediments10, driven by sinking particulate and flocculated materials, likely lock up enough C to offset the quantity lost to the atmosphere through CH4 diffusion (Fig. 1). Nonetheless, this important body of work provides a regional-scale perspective that brings us closer to understanding the contemporary warming potential of Arctic lakes.As the Arctic continues to warm, aquatic ecosystems’ C dynamics remain poorly understood. Now it appears that most Arctic lakes are not major sites of old C loss. However, the Artic landscape is changing, and current evidence1 suggests that old C is largely being processed higher in the flow path, closer to soil sources. An important take-home message is that the research community is still struggling to capture the extremely variable nature of lake ecosystems and their responses to climate change.References1. Hugelius, G. et al. Biogeosciences 11, 6573–6593 (2014).2. Schuur, E. A. G. et al. Nature 520, 171–179 (2015).3. Walter Anthony, K. et al. Nat. Geosci. 9, 679–682 (2016).4. Elder, C. D. et al. Nat. Clim. Change (2018).5. Verpoorter, C., Kutser, T., Seekell, D. A. & Tranvik, L. J. Geophys. Res. Lett. 41, 6396–6402 (2014).6. Kling, G. W., Kipphut, G. W. & Miller, M. C. Science 251, 298–301 (1991).7. Wik, M., Varner, R. K., Anthony, K. W., MacIntyre, S. & Bastviken, D. Nat. Geosci. 9, 99–105 (2016).8. IPCC Climate Change 2013: The Physical Science Basis (eds Stocker, T. F. et al.) (Cambridge Univ. Press, 2013).9. Stackpoole, S. M. et al. Ecol. Appl. 27, 1403–1420 (2017).10. Anderson, N.J., D'Andrea, W. & Fritz, S.C. Global Change Biol. 15, 2590–2598 (2009).Borges, A.V., Abril, G., Bouillon, S., 2018. Carbon dynamics and CO2 and CH4 outgassing in the Mekong delta. Biogeosciences 15, 1093-1114. report a data set of biogeochemical variables related to carbon cycling obtained in the three branches (M? Tho, Hàm Lu?ng, C? Chiên) of the Mekong delta (B?n Tre province, Vietnam) in December 2003, April 2004, and October 2004. Both the inner estuary (upstream of the mouth) and the outer estuary (river plume) were sampled, as well as side channels. The values of the partial pressure of CO2 (pCO2) ranged between 232 and 4085?ppm, O2 saturation level (%O2) between 63 and 114?%, and CH4 between 2 and 2217?nmol?L?1, within the ranges of values previously reported in temperate and tropical meso- and macro-tidal estuaries. Strong seasonal variations were observed. In the upper oligohaline estuary, low pCO2 (479–753?ppm) and high %O2 (98–106?%) values were observed in April 2004 most probably related to freshwater phytoplankton growth owing to low freshwater discharge (1400?m3?s?1) and increase in water residence time; during the two other sampling periods with a higher freshwater discharge (9300–17?900?m3?s?1), higher pCO2 (1895–2664?ppm) and lower %O2 (69–84?%) values were observed in the oligohaline part of the estuary. In October 2004, important phytoplankton growth occurred in the offshore part of the river plume as attested by changes in the contribution of particulate organic carbon (POC) to total suspended matter (TSM) (%POC) and the stable isotope composition of POC (δ13C-POC), possibly related to low TSM values (improvement of light conditions for phytoplankton development), leading to low pCO2 (232?ppm) and high %O2 (114?%) values. Water in the side channels in the Mekong delta was strongly impacted by inputs from the extensive shrimp farming ponds. The values of pCO2, CH4, %O2, and the stable isotope composition of dissolved inorganic carbon (δ13C-DIC) indicated intense organic matter degradation that was partly mediated by sulfate reduction in sediments, as revealed by the slope of total alkalinity (TA) and DIC covariations. The δ13C-POC variations also indicated intense phytoplankton growth in the side channels, presumably due to nutrient enrichment related to the shrimp farming ponds. A data set in the mangrove creeks of the Ca Mau province (part of the Mekong delta) was also acquired in April and October 2004. These data extended the range of variability in pCO2 and %O2 with more extreme values than in the Mekong delta (B?n Tre), with maxima and minima of 6912?ppm and 37?%, respectively. Similarly, the maximum CH4 concentration (686?nmol?L?1) was higher in the Ca Mau province mangrove creeks than in the Mekong delta (B?n Tre, maximum 222?nmol?L?1) during the October 2004 cruise (rainy season and high freshwater discharge period). In April 2004 (dry season and low freshwater discharge period), the CH4 values were much lower than in October 2004 (average 19?±?13 and 210?±?158?nmol?L?1, respectively) in the Ca Mau province mangrove creeks, owing to the higher salinity (average 33.2?±?0.6 and 14.1?±?1.2, respectively) that probably led to higher sediment sulfate reduction, leading to inhibition of sediment methanogenesis and higher anaerobic CH4 oxidation. In the inner estuarine region (three branches of the Mekong delta), CO2 emissions to the atmosphere averaged 121?mmol?m?2?d?1, and the CH4 emissions averaged 118??mol?m?2?d?1. The CO2 emission to the atmosphere from the Mekong inner estuary was higher than reported in the Yangtze and Pearl river inner estuaries. This was probably due to the lower salinity in the Mekong delta branches, possibly due to different morphology: relatively linear channels in the Mekong delta versus funnel-shaped estuaries for the Yangtze and Pearl river inner estuaries.Botting, J.P., Muir, L.A., 2018. Early sponge evolution: A review and phylogenetic framework. Palaeoworld 27, 1-29. are one of the critical groups in understanding the early evolution of animals. Traditional views of these relationships are currently being challenged by molecular data, but the debate has so far made little use of recent palaeontological advances that provide an independent perspective on deep sponge evolution. This review summarises the available information, particularly where the fossil record reveals extinct character combinations that directly impinge on our understanding of high-level relationships and evolutionary origins. An evolutionary outline is proposed that includes the major early fossil groups, combining the fossil record with molecular phylogenetics. The key points are as follows. (1) Crown-group sponge classes are difficult to recognise in the fossil record, with the exception of demosponges, the origins of which are now becoming clear. (2) Hexactine spicules were present in the stem lineages of Hexactinellida, Demospongiae, Silicea and probably also Calcarea and Porifera; this spicule type is not diagnostic of hexactinellids in the fossil record. (3) Reticulosans form the stem lineage of Silicea, and probably also Porifera. (4) At least some early-branching groups possessed biminerallic spicules of silica (with axial filament) combined with an outer layer of calcite secreted within an organic sheath. (5) Spicules are homologous within Silicea, but also between Silicea and Calcarea, and perhaps with Homoscleromorpha. (6) The last common ancestor of extant sponges was probably a thin-walled, hexactine-bearing sponge with biminerallic spicules. (7) The stem group of sponges included tetraradially-symmetric taxa that grade morphologically into Cambrian fossils described as ctenophores. (8) The protomonaxonid sponges are an early-branching group, probably derived from the poriferan stem lineage, and include the problematic chancelloriids as derived members of the piraniid lineage. (9) There are no definite records of Precambrian sponges: isolated hexactine-like spicules may instead be derived from radiolarians. Early sponges had mineralised skeletons and thus should have a good preservation potential: the lack of sponge fossils in Precambrian strata may be due to genuine absence of sponges. (10) In contrast to molecular clock and biomarker evidence, the fossil record indicates a basal Cambrian diversification of the main sponge lineages, and a clear relationship to ctenophore-like ancestors. Overall, the early sponge fossil record reveals a diverse suite of extinct and surprising character combinations that illustrate the origins of the major lineages; however, there are still unanswered questions that require further detailed studies of the morphology, mineralogy and structure of early sponges.Bowen, L., Miles, A.K., Ballachey, B., Waters, S., Bodkin, J., Lindeberg, M., Esler, D., 2018. Gene transcription patterns in response to low level petroleum contaminants in Mytilus trossulus from field sites and harbors in southcentral Alaska. Deep Sea Research Part II: Topical Studies in Oceanography 147, 27-35. 1989 Exxon Valdez oil spill damaged a wide range of natural resources, including intertidal communities, and post-spill studies demonstrated acute and chronic exposure and injury to an array of species. Standard toxicological methods to evaluate petroleum contaminants have assessed tissue burdens, with fewer assays providing indicators of health or physiology, particularly when contaminant levels are low and chronic. Marine mussels are a ubiquitous and crucial component of the nearshore environment, and new genomic technologies exist to quantify molecular responses of individual mussels to stimuli, including exposure to polycyclic aromatic hydrocarbons (PAHs). We used gene-based assays of exposure and physiological function to assess chronic oil contamination using the Pacific blue mussel, Mytilus trossulus. We developed a diagnostic gene transcription panel to investigate exposure to PAHs and other contaminants and its effects on mussel physiology and health. During 2012–2015, we analyzed mussels from five field sites in western Prince William Sound, Alaska, with varying oil histories from the 1989 Exxon Valdez oil spill, and from three boat harbors in the area. Gene transcription patterns of mussels from harbors were consistent with elevated exposure to PAHs or other contaminants, whereas transcription patterns of mussels sampled from shorelines in areas affected by the oil spill indicated no PAH exposure.Bowman, D.T., Jobst, K.J., Ortiz, X., Reiner, E.J., Warren, L.A., McCarry, B.E., Slater, G.F., 2018. Improved coverage of naphthenic acid fraction compounds by comprehensive two-dimensional gas chromatography coupled with high resolution mass spectrometry. Journal of Chromatography A 1536, 88-95. study reports the first application of comprehensive two-dimensional gas chromatography coupled to a high-resolution quadrupole time-of-flight mass spectrometer (GC × GC/HRQTOF-MS) for the characterization of naphthenic acid fraction compounds (NAFCs) from the Alberta Oil Sands. High resolution mass spectrometry (HRMS) significantly increased the coverage of NAFCs in the mixture and allowed the differentiation of NAFCs from several chemical classes. It was demonstrated that GC × GC, in combination with the high mass accuracy and precision of the HRQTOF-MS, could distinguish chemical species with the C3 vs SH4 mass split at a much lower resolving power than required with direct infusion experiments. Mass defect plots were useful for visualizing the complex datasets generated by GC × GC/HRQTOF-MS and led to the identification of 1105 chemical species with unique elemental compositions (<5 ppm mass accuracy). Mass defect plots were shown to be a powerful screening tool and enabled the detection of extensive isomer series from the SO2 chemical class, some of which have not been previously reported in oil sands related samples. The GC × GC/HRQTOF-MS approach is expected to improve NAFC monitoring programs since the technique allows the qualitative analysis of individual NAFCs and provides unique fingerprints via isomer distributions which may assist in future fingerprinting studies.Boytsova, A., Kondrasheva, N., Ancheyta, J., 2018. Pyrolysis kinetics of heavy oil asphaltenes under steam atmosphere at different pressures. Energy & Fuels 32, 1132-1138. analysis was used to study the pressure effect on the activation energy during asphaltene gasification. The experiments were carried out under steam atmosphere at different pressures (1–80 bar) and temperatures (100–900 °C). The measured values of the total mass loss of asphaltenes are pressure dependent. They increase with rising pressure. Kinetic parameters were determined using a first-order kinetic model and integral method with thermogravimetric analysis data. The activation energy was found to vary from 189.6 to 130.4 kJ/mol and frequency factor from 4.1 × 1010 to 1.2 × 106 min–1. A decrease of both parameters was observed with an increasing pressure. Coke produced during the gasification is obviously characterized by the bigger pore size and weaker mechanical strength as the pressure increases from 1 to 80 bar. The structure of the produced coke becomes more crumbly with raising pressure. The formation of spherical carbon particles with a radius of around 5 μm was observed at high pressure (20–80 bar). The elemental composition of these particles is roughly equal: C (～97%), S (～2%), and O (～1%).Brits, M., Gorst-Allman, P., Rohwer, E.R., De Vos, J., de Boer, J., Weiss, J.M., 2018. Comprehensive two-dimensional gas chromatography coupled to high resolution time-of-flight mass spectrometry for screening of organohalogenated compounds in cat hair. Journal of Chromatography A 1536, 151-162. coupling of comprehensive two-dimensional gas chromatography with high-resolution time-of-flight mass spectrometry offers the best separation efficiency combined with accurate mass measurements over a wide mass range. The tremendous power of this screening tool is illustrated by trace qualitative screening analysis of organohalogenated compounds (OHCs) in pet cat hair. Tentative identification was supported by mass spectral database searches and elemental formula prediction from the experimentally determined accurate mass data. This screening approach resulted in the first tentative identification of pentabromoethylbenzene, decabromodiphenyl ethane, hexabromocyclododecane, trisbromoneopentyl alcohol, tris(2-chloroethyl) phosphate and tris(2-chloroisopropyl)phosphate in the South African indoor environment. A total of seventy-two OHCs were identified in the samples and include known flame retardants, such as polybrominated diphenyl ethers, and legacy contaminants such as polychlorinated biphenyls and organochlorine, organophosphorous and pyrethroid pesticides. The results obtained from cat hair indicate that these pets are exposed to complex mixtures of OHCs and the detection of these compounds suggests that non-invasive cat hair samples can be used to model indoor exposure with reference to external deposition of OHCs present in the air and dust surrounding people. Toddlers share the same environment as pet cats and therefore also the same health risks.Brodie, M.W., Aplin, A.C., Hart, B., Orland, I.J., Valley, J.W., Boyce, A.J., 2018. Oxygen isotope microanalysis by secondary ion mass spectrometry suggests continuous 300-million-year history of calcite cementation and dolomitization in the Devonian Bakken Formation. Journal of Sedimentary Research 88, 91-104. cementation and dolomitization are key diagenetic processes in many sedimentary systems. Unravelling detailed histories and timescales of cementation and replacement is, however, often compromised by the limited spatial resolution of many analytical techniques; in some cases multiple grains are co-analyzed so that diagenetic histories are blurred and reaction periods are difficult to establish. In this study we have used 10-micrometer-resolution, in situ secondary ion mass spectrometry to determine the oxygen isotope composition of 197 individual, 10–50-micrometer-size crystals of dolomite and calcite from six samples in a single core of Upper Devonian middle Bakken Member siltstones and sandstones, the major tight oil formation of the Williston basin, USA. This amount of data places important constraints on the range of temperatures and times that carbonate cementation and replacement occurred. Petrographic data show that microcrystalline calcite cement is an early phase, and combined with mineralogical data suggest that much of the dolomite replaces calcite. Over spatial scales of less than a centimeter, analyses of individual calcite crystals have a range of 5‰ for δ18O in the group of crystals, and for the group of individual dolomite crystals, 10‰. These sub-centimeter ranges are as great as those observed in previous studies of carbonate cements sampled over many meters and remind us that previous low-resolution studies may have inadvertently analyzed mixed phases. There is no relationship between dolomite texture and isotopic composition at this spatial scale; microscale backscattered electron imagery and scanning electron microscopy cathodoluminescence zoning is seen, but cannot be resolved with a 10-micrometer spot size. Assuming, since it is an early cement, that calcite precipitated from seawater (δ18O = –1.5‰), it formed at ca. 15–40°C, mainly at the lower temperatures. Present-day formation waters in Devonian rocks in this region have oxygen isotope compositions of 7–8‰ VSMOW. Using these values as a likely dolomitizing fluid, we suggest that dolomitization occurred continuously between 40 and 140°C over 150–200 million years, most likely in a fluid with a high Mg/Ca ratio resulting from gypsum formation in local evaporites. We suggest that this exceptionally low rate of dolomitization was controlled by the low rate of supply of Mg in a very sluggish flow regime; dolomitization is incomplete because of a limited supply of Mg.Br?nner, U., Johansen, ?., Leirvik, F., Nordam, T., S?rheim, K.R., 2018. Spreading of waxy oils on calm water. Marine Pollution Bulletin 129, 135-141. objective of this paper is to provide a simple extension of the much-used gravity spreading model for oil on calm water to account for the spreading behavior of waxy crude oils in cold waters – including the observed retardation and eventual termination of spreading at certain oil film thicknesses. This peculiar behavior is not predicted by traditional spreading models for oil on calm water (i.e. viscous-gravity spreading models), but may occur due to non-Newtonian oil properties caused by precipitation of wax at low temperatures. To clarify the spreading behavior of such oils, SINTEF has conducted a series of laboratory experiments with a range of waxy oil mixtures. The present paper contains analyses of data from these experiments, including favorable comparisons with calculations by a proposed improved surface spreading model.Burnham, A.K., 2018. Thermomechanical properties of the Garden Gulch Member of the Green River Formation. Fuel 219, 477-491. well logging and laboratory rock mechanics experiments gathered within the context of in-situ retorting are used to derive an anisotropic thermomechanical model for deformation of oil shale from the Garden Gulch Member of the Green River Formation in the Piceance Basin of Colorado. Elastic moduli determined from sonic velocities are shown to be consistent with but about twice as high as those from static measurements at small strain. Porosity correlates inversely with organic content, and the relative contributions of kerogen, minerals, and porosity to sonic velocities are determined from a combination of new and literature data. Young’s modulus of kerogen derived by extrapolation to high kerogen volume fraction is consistent with measurements from previous workers. The temperature dependence and anisotropy of the triaxial tests can be described fairly well by Reuss and Voigt averages for a laminar material. The intrinsic (end-member) static Young’s moduli of the kerogen and mineral components are 1 and 7 GPa, respectively, with thermal softening of each described by apparent activation energies of 17 and 9?kJ/mol, respectively. Isostatic compression creep tests are used to further constrain the temperature dependence of the plastic deformation viscosity. The apparent activation energy for creep is about 35?kJ/mol. The thermochemical properties of the clay-rich Garden Gulch Member are compared to those of the dolomite-rich Parachute Creek Member. At low organic content, the Young’s modulus of the Garden Gulch Member is about four times lower, and the properties of the two members approach each other for high organic content.Burton, Z.F.M., Moldowan, J.M., Sykes, R., Graham, S.A., 2018. Unraveling petroleum degradation, maturity, and mixing and addressing impact on petroleum prospectivity: Insights from frontier exploration regions in New Zealand. Energy & Fuels 32, 1287-1296. oil quality is essential to identifying valuable resource accumulations. However, in new areas of exploration, little information is available on the processes affecting resource quality. Geochemical analyses of oil seeps from frontier regions of New Zealand’s East Coast illustrate an application of underutilized resource quality assessment techniques. Distributions of n-alkanes and isoprenoids reveal biodegradation, and thus potentially lower oil quality in the “southern” versus the “northern” oil seeps. However, sterane and terpane compounds are unaltered, indicating overall biodegradation of these oils is low to moderate. Additionally, lack of 25-norhopane indicates degradation of southern oils may be solely aerobic. Therefore, any subsurface accumulations are potentially unaffected. Investigation of sterane and hopane isomerization ratios and additional sterane and terpane maturity parameters is paired with diamondoid analyses of oil-to-gas conversion and petroleum mixing. Three distinct petroleum mixtures are identified among the sampled seeps: (1) a seep composed of an early/peak oil window component and an intensely cracked condensate/wet gas component, (2) seeps solely containing a peak/late oil window component, and (3) seeps composed of a peak/late oil window component and an intensely cracked condensate/wet gas component. Identified components indicate at least three distinct charges or stages of petroleum generation. Black oil components might indicate actively producing source rock in all regions represented by the seeps. Intensely cracked components indicate petroleum mixing via thermogenic gas infiltration and suggest an effect on oil quality. Important questions concerning migration pathways and timing, ties to New Zealand’s offshore basins, and potential for reservoir entrapment of these petroleum components remain.Buttigieg, P.L., Fadeev, E., Bienhold, C., Hehemann, L., Offre, P., Boetius, A., 2018. Marine microbes in 4D — using time series observation to assess the dynamics of the ocean microbiome and its links to ocean health. Current Opinion in Microbiology 43, 169-185. observation is of high relevance in assessing marine phenomena of scientific and societal concern including ocean productivity, harmful algal blooms, and pathogen exposure. However, we have yet to realise its potential to coherently and comprehensively report on global ocean status. The ability of satellites to monitor the distribution of phytoplankton has transformed our appreciation of microbes as the foundation of key ecosystem services; however, more in-depth understanding of microbial dynamics is needed to fully assess natural and anthropogenically induced variation in ocean ecosystems. While this first synthesis shows that notable efforts exist, vast regions such as the ocean depths, the open ocean, the polar oceans, and most of the Southern Hemisphere lack consistent observation. To secure a coordinated future for a global microbial observing system, existing long-term efforts must be better networked to generate shared bioindicators of the Global Ocean's state and health.Byrnes, J.S., Karlstrom, L., 2018. Anomalous K-Pg–aged seafloor attributed to impact-induced mid-ocean ridge magmatism. Science Advances 4, Article eaao2994. phenomena at all scales, from hydrothermal geysers to flood basalts, can potentially be initiated or modulated by external mechanical perturbations. We present evidence for the triggering of magmatism on a global scale by the Chicxulub meteorite impact at the Cretaceous-Paleogene (K-Pg) boundary, recorded by transiently increased crustal production at mid-ocean ridges. Concentrated positive free-air gravity and coincident seafloor topographic anomalies, associated with seafloor created at fast-spreading rates, suggest volumes of excess magmatism in the range of ~105 to 106 km3. Widespread mobilization of existing mantle melt by post-impact seismic radiation can explain the volume and distribution of the anomalous crust. This massive but short-lived pulse of marine magmatism should be considered alongside the Chicxulub impact and Deccan Traps as a contributor to geochemical anomalies and environmental changes at K-Pg time.Cabestrero, ?., del Buey, P., Sanz-Montero, M.E., 2018. Biosedimentary and geochemical constraints on the precipitation of mineral crusts in shallow sulphate lakes. Sedimentary Geology 366, 32-46. desiccation of Mg2+–(Na+)–(Ca2+)–SO42?–(Cl?) saline lakes in La Mancha (Central Spain) that host microbial mats led to the precipitation of hydrated Na-Mg sulphates and gypsum. Sulphates precipitated in the submerged conditions form extensive biolaminites, whilst in marginal areas they produce thin crusts. Sedimentological, mineralogical, petrographic and high resolution textural studies reveal that the crusts were formed within the benthic microbial mats that thrive at salinities ranging from 160 to 340?g·L?1. The minerals of the crusts are primary bloedite (Na2Mg(SO4)2·4H2O), epsomite (MgSO4·7H2O), gypsum (CaSO4·2H2O) and mirabilite (Na2SO4·10H2O), as well as secondary hexahydrite (MgSO4·6H2O) and thenardite (Na2SO4). Primary bloedite crystals, which form the framework of surficial and submerged crusts are seen to nucleate subaqueously and grow incorporatively within the matgrounds. Displacive and incorporative epsomite grows on previous bloedite crystals and also on the ground. Mirabilite is precipitated rapidly at the brine-air interface over bloedite and epsomite. Hexahydrite and thenardite are formed due to dehydration of epsomite and mirabilite, respectively.Hydrochemical modeling with PHREEQC indicated that evaporitic biolaminites are forming from brines undersaturated with respect to bloedite, epsomite and mirabilite, which suggests that the microorganisms contribute to the heterogeneous nucleation of the sulphates in the microbial mats.Unlike carbonates, the influence of microbes on the growth and morphology of complicated double salts such as bloedite has not been documented previously and provides a new perspective on the formation of hydrated sulphate minerals that are common on Earth as well as other planets.Caccamo, P.D., Brun, Y.V., 2018. The molecular basis of noncanonical bacterial morphology. Trends in Microbiology 26, 191-208. come in a wide variety of shapes and sizes. The true picture of bacterial morphological diversity is likely skewed due to an experimental focus on pathogens and industrially relevant organisms. Indeed, most of the work elucidating the genes and molecular processes involved in maintaining bacterial morphology has been limited to rod- or coccal-shaped model systems. The mechanisms of shape evolution, the molecular processes underlying diverse shapes and growth modes, and how individual cells can dynamically modulate their shape are just beginning to be revealed. Here we discuss recent work aimed at advancing our knowledge of shape diversity and uncovering the molecular basis for shape generation in noncanonical and morphologically complex bacteria.Callaway, E., 2018. Israeli fossils are the oldest modern humans ever found outside of Africa. Nature 554, 15-16. and teeth mark Homo sapiens' early arrival on the Arabian Peninsula. The oldest human fossils ever found outside Africa suggest that Homo sapiens might have spread to the Arabian Peninsula around 180,000 years ago — much earlier than previously thought. The upper jaw and teeth, found in an Israeli cave and reported in Science on 25 January1, pre-date other human fossils from the same region by at least 50,000 years. But scientists say that it is unclear whether the fossils represent a brief incursion or a more-lasting expansion of the species.Researchers originally thought that H. sapiens emerged in East Africa 200,000 years ago, then moved out to populate the rest of the world. Until discoveries in the past decade countered that story, scientists thought that a small group left Africa some 60,000 years ago. If so, it would mean that signs of earlier travels, including 80,000–120,000-year-old skulls and other remains from Israel, uncovered in the 1920s and 1930s, were from failed migrations.However, recent discoveries have muddied that simple narrative. Some H. sapiens-like fossils from Morocco that are older than 300,000 years, reported last year2, have raised the possibility that humans evolved earlier and perhaps elsewhere in Africa. Teeth from southern China, described in 20153, hint at long-distance migrations some 120,000 years ago. And genome studies have sown more confusion, with some comparisons of global populations pointing to just one human migration from Africa4,5, and others suggesting multiple waves6.Early startIn the early 2000s, archaeologist Mina Weinstein-Evron, at the University of Haifa in Israel, and palaeoanthropologist Israel Hershkowitz, at Tel Aviv University, began a project to excavate a series of Israeli caves. “We called it ‘Searching for the Origins of the Earliest Modern Humans’. This was what we were looking for,” says Weinstein-Evron.Their team discovered the jaw fragment in 2002, in Misliya Cave, the highest of Mt Carmel’s caves. It is just a few kilometres away from the Skhul cave, one of the sites where the 80,000–120,000-year-old remains were found in the 1920s and 1930s. Using several different methods, the team estimates the jaw and teeth to be 177,000–194,000 years old.The remains are unquestionably H. sapiens, says team member María Martinón-Torres, a palaeoanthropologist at the National Research Centre on Human Evolution in Burgos, Spain. The shapes of the teeth match those of both modern and ancient humans, she says. They also lack features typical of Neanderthals, which lived throughout Eurasia at the time.The dating seems solid and the fossils are H. sapiens, says Huw Groucutt, an archaeologist at the University of Oxford, UK. But he isn’t very surprised to see them in Israel. He and his colleagues have previously said that 175,000-year-old stone tools from other sites in the Middle East resemble those used by H. sapiens in East Africa7.Close encountersHershkowitz says that the jaw and teeth point to a long-term occupation of the Middle East by early H. sapiens. “It was a central train station. People were coming and going through this land corridor from one continent to another, and it was occupied all the time.” Once in the region, humans probably encountered and interbred with Neanderthals, Hershkowitz says, pointing to a 2017 ancient-DNA study that suggested interbreeding had occurred before 200,000 years ago8.Wet periods could have drawn humans into the Middle East, but long, dry spells mean that “the region was probably more often a ‘boulevard of broken dreams’ than a stable haven for early humans”, write Chris Stringer and Julia Galway-Witham, palaeoanthropologists at the Natural History Museum in London, in a commentary accompanying the paper9.The fossil could indicate that Israel and the rest of the Arabian Peninsula were part of a larger region in which H. sapiens evolved, says John Shea, an archaeologist at Stony Brook University in New York. “We tend to think of Israel as part of Asia for geopolitical reasons, but it is really a transition zone between North Africa and western Asia,” he says. “Plenty of Afro-Arabian animals live there, or did so until recently,” including leopards, lions and zebras. “Homo sapiens,” Shea says, “is just another such Afro-Arabian species.” References1. Hershkovitz, I. et al. Science (2018).2. Hublin, J.-J. et al. Nature 546, 289–292 (2017).3. Liu, W. et al. Nature 526, 696–699 (2015).4. Mallick, S. et al. Nature 538, 201–206 (2016).5. Malaspinas, A.-S. et al. Nature 538, 207–214 (2016).6. Pagani, L. et al. Nature 538, 238–242 (2016).7. Groucutt H. et al. Quat. Int. 382, 8–30 (2015).8. Posth, C. et al. Nature Commun. 8, 16046 (2017).9. Stringer, C. & Galway-Witham, J. Science 359, 389–390 (2018).Callow, B., Falcon-Suarez, I., Ahmed, S., Matter, J., 2018. Assessing the carbon sequestration potential of basalt using X-ray micro-CT and rock mechanics. International Journal of Greenhouse Gas Control 70, 146-156. carbonation in basaltic rock provides a permanent storage solution for the mitigation of anthropogenic CO2 emissions in the atmosphere. 3D X-ray micro-CT (XCT) image analysis is applied to a core sample from the main basaltic reservoir of the CarbFix site in Iceland, which obtained a connected porosity of 2.05–8.76%, a reactive surface area of 0.10–0.33?mm?1 and a larger vertical permeability (2.07?×?10?10?m2) compared to horizontal permeability (5.10?×?10?11?m2). The calculations suggest a CO2 storage capacity of 0.33 Gigatonnes at the CarbFix pilot site. The XCT results were compared to those obtained from a hydromechanical test applied to the same sample, during which permeability, electrical resistivity and volumetric deformation were measured under realistic reservoir pressure conditions. It was found that permeability is highly stress sensitive, dropping by two orders of magnitude for a ?0.02% volumetric deformation change, equivalent to a mean pore diameter reduction of 5?μm. This pore contraction was insufficient to explain such a permeability reduction according to the XCT analysis, unless combined with the effects of clay swelling and secondary mineral pore clogging. The findings provide important benchmark data for the future upscaling and optimisation of CO2 storage in basalt formations.Cantine, M.D., Fournier, G.P., 2018. Environmental adaptation from the origin of life to the Last Universal Common Ancestor. Origins of Life and Evolution of Biospheres 48, 35-54. fundamental molecular and biological evolution took place between the prebiotic origins of life and the state of the Last Universal Common Ancestor (LUCA). Considering the evolutionary innovations between these two endpoints from the perspective of environmental adaptation, we explore the hypothesis that LUCA was temporally, spatially, and environmentally distinct from life’s earliest origins in an RNA world. Using this lens, we interpret several molecular biological features as indicating an environmental transition between a cold, radiation-shielded origin of life and a mesophilic, surface-dwelling LUCA. Cellularity provides motility and permits Darwinian evolution by connecting genetic material and its products, and thus establishing heredity and lineage. Considering the importance of compartmentalization and motility, we propose that the early emergence of cellularity is required for environmental dispersal and diversification during these transitions. Early diversification and the emergence of ecology before LUCA could be an important pre-adaptation for life’s persistence on a changing planet.Cao, J.-L., Wang, S.-S., Hu, H., He, C.-W., Wan, J.-B., Su, H.-X., Wang, Y.-T., Li, P., 2018. Online comprehensive two-dimensional hydrophilic interaction chromatography × reversed-phase liquid chromatography coupled with hybrid linear ion trap Orbitrap mass spectrometry for the analysis of phenolic acids in Salvia miltiorrhiza. Journal of Chromatography A 1536, 216-227. the present study, a system was developed for the analysis of phenolic acids in Salvia miltiorrhiza using online comprehensive two-dimensional hydrophilic interaction chromatography and reversed-phase liquid chromatography coupled to a DAD detector and hybrid linear ion trap-Orbitrap mass spectrometry (HILIC × RP-DAD-ESI/HRMS/MSn). The system was configured based on the combination of an XBridge Amide column (150 mm × 4.6 mm, 3.5 μm) and Accucore PFP column (50 mm × 4.6 mm, 2.6 μm) for the first and second dimensions, respectively. An additional LC pump was used to dilute the eluent from the first dimension to decrease its elution strength in the second dimension. A back-flush trap column was selected as an interface to make up for the loss of efficiency and resolution due to the online dilution. Under the optimized conditions, a total of 196 peaks of polar compounds were successfully separated and detected in Salvia miltiorrhiza using the developed online HILIC × RP system, which exhibited high orthogonality (73%). The online combination of HILIC and RP provides powerful separation capability for the analysis of polar compounds in samples with complex matrices.Cao, J., Yang, R., Yin, W., Hu, G., Bian, L., Fu, X., 2018. Mechanism of organic matter accumulation in residual bay environments: The Early Cretaceous Qiangtang Basin, Tibet. Energy & Fuels 32, 1024-1037. controlling mechanisms for the accumulation and preservation of organic matter in residual bay environments during the transition from marine to continental settings are not well understood, although oil–gas source rocks can form in this setting. In this study, we develop a case study for the Early Cretaceous black rock series in the northern Qiangtang Basin, Tibet (i.e., the Upper Member of the Suowa Formation), by conducting a combined organic and inorganic geochemical analysis of micritic limestone, marl, and shale samples from an outcrop section. Results show that total organic carbon (TOC) contents of the studied samples are between 1.74% and 7.71%, with the organic matter being Type II/III kerogen. Of the three factors that could influence the observed TOCs and organic matter types, including paleoproductivity, preservational environment, and sedimentation rate, the preservational environment appears to be the dominant factor, independent of lithology. This is typically supported by the relatively modest covariance between redox-sensitive parameters and TOC contents, e.g., R2 = 0.625 in the Mn/Ca-TOC diagram and R2 = 0.690 in the U/Th-TOC diagram. This suggests that the suboxic–anoxic environment in the lagoon at the residual bay area promoted favorable conditions for organic matter preservation. In contrast, the other two factors, i.e., paleoproductivity and the rate of sedimentation, differed between three types of lithologies. For shales and micritic limestones, the effect of paleoproductivity was limited on the abundance of organic matter, and no significant effect of sedimentation rate was detected. In contrast, the paleoproductivity has a definite effect on the amount of organic matter preserved in the marls. These findings also add to our knowledge of the depositional environment that existed during the Early Cretaceous marine–continental transition in the Qiangtang Basin and further built our understanding of the potential hydrocarbon resources of the basin.Cao, X., Aiken, G.R., Butler, K.D., Mao, J., Schmidt-Rohr, K., 2018. Comparison of the chemical composition of dissolved organic matter in three lakes in Minnesota. Environmental Science & Technology 52, 1747-1755. information on the chemical composition of dissolved organic matter (DOM) in three lakes in Minnesota has been gained from spectral editing and two-dimensional nuclear magnetic resonance (NMR) methods, indicating the effects of lake hydrological settings on DOM composition. Williams Lake (WL), Shingobee Lake (SL), and Manganika Lake (ML) had different source inputs, and the lake water residence time (WRT) of WL was markedly longer than that of SL and ML. The hydrophobic organic acid (HPOA) and transphilic organic acid (TPIA) fractions combined comprised >50% of total DOM in these lakes, and contained carboxyl-rich alicyclic molecules (CRAM), aromatics, carbohydrates, and N-containing compounds. The previously understudied TPIA fractions contained fewer aromatics, more oxygen-rich CRAM, and more N-containing compounds compared to the corresponding HPOA. CRAM represented the predominant component in DOM from all lakes studied, and more so in WL than in SL and ML. Aromatics including lignin residues and phenols decreased in relative abundances from ML to SL and WL. Carbohydrates and N-containing compounds were minor components in both HPOA and TPIA and did not show large variations among the three lakes. The increased relative abundances of CRAM in DOM from ML, SL to WL suggested the selective preservation of CRAM with increased residence time.Carey, C.C., McClure, R.P., Doubek, J.P., Lofton, M.E., Ward, N.K., Scott, D.T., 2018. Chaoborus spp. transport CH4 from the sediments to the surface waters of a eutrophic reservoir, but their contribution to water column CH4 concentrations and diffusive efflux is minor. Environmental Science & Technology 52, 1165-1173. spp. (midge larvae) live in the anoxic sediments and hypolimnia of freshwater lakes and reservoirs during the day and migrate to the surface waters at night to feed on plankton. It has recently been proposed that Chaoborus take up methane (CH4) from the sediments in their tracheal gas sacs, use this acquired buoyancy to ascend into the surface waters, and then release the CH4, thereby serving as a CH4 “pump” to the atmosphere. We tested this hypothesis using diel surveys and seasonal monitoring, as well as incubations of Chaoborus to measure CH4 transport in their gas sacs at different depths and times in a eutrophic reservoir. We found that Chaoborus transported CH4 from the hypolimnion to the lower epilimnion at dusk, but the overall rate of CH4 transport was minor, and incubations revealed substantial variability in CH4 transport over space and time. We calculated that Chaoborus transport ～0.1 mmol CH4 m–2 yr–1 to the epilimnion in our study reservoir, a very low proportion (<1%) of total CH4 diffusive flux during the summer stratified period. Our data further indicate that CH4 transport by Chaoborus is sensitive to water column mixing, Chaoborus density, and Chaoborus species identity.Carrel, M., Morales, V.L., Beltran, M.A., Derlon, N., Kaufmann, R., Morgenroth, E., Holzner, M., 2018. Biofilms in 3D porous media: Delineating the influence of the pore network geometry, flow and mass transfer on biofilm development. Water Research 134, 280-291. study investigates the functional correspondence between porescale hydrodynamics, mass transfer, pore structure and biofilm morphology during progressive biofilm colonization of a porous medium. Hydrodynamics and the structure of both the porous medium and the biofilm are experimentally measured with 3D particle tracking velocimetry and micro X-ray Computed Tomography, respectively. The analysis focuses on data obtained in a clean porous medium after 36?h of biofilm growth. Registration of the particle tracking and X-ray data sets allows to delineate the interplay between porous medium geometry, hydrodynamic and mass transfer processes on the morphology of the developing biofilm. A local analysis revealed wide distributions of wall shear stresses and concentration boundary layer thicknesses. The spatial distribution of the biofilm patches uncovered that the wall shear stresses controlled the biofilm development. Neither external nor internal mass transfer limitations were noticeable in the considered system, consistent with the excess supply of nutrient and electron acceptors. The wall shear stress remained constant in the vicinity of the biofilm but increased substantially elsewhere.Carvalho, L., Monteiro, R., Figueira, P., Mieiro, C., Almeida, J., Pereira, E., Magalh?es, V., Pinheiro, L., Vale, C., 2018. Vertical distribution of major, minor and trace elements in sediments from mud volcanoes of the Gulf of Cadiz: evidence of Cd, As and Ba fronts in upper layers. Deep Sea Research Part I: Oceanographic Research Papers 131, 133-143. volcanoes are feature of the coastal margins where anaerobic oxidation of methane triggers geochemical signals. Elemental composition, percentage of fine particles and loss on ignition were determined in sediment layers of eleven gravity cores retrieved from four mud volcanoes (Sagres, Bonjardim, Soloviev and Porto) and three undefined structures located on the deep Portuguese margin of the Gulf of Cadiz. Calcium was positively correlated to Sr and inversely to Al as well as to most of the trace elements. Vertical profiles of Ba, Cd and As concentrations, and their ratios to Al, in Porto and Soloviev showed pronounced enhancements in the top 50-cm depth. Sub-surface enhancements were less pronounced in other mud volcanoes and were absent in sediments from the structures. These profiles were interpreted as diagenetic enrichments related to the anaerobic oxidation of methane originated from upward methane-rich fluxes. The observed barium fronts were most likely caused by the presence of barite which precipitated at the sulphate-methane transition zone. Cd and As enrichments have probably resulted from successive dissolution/precipitation of sulphides in response to vertical shifts of redox boundaries.Cavalcante, C., de Oliveira, J.P., Hamada, J., de Siqueira, F.A., Nascimento, A.N.d., 2018. Sequential extraction procedure for the separation of Ni and V species in crude oil and analysis by ETAAS, GC–MS, and IR. Fuel 220, 631-637. determination of nickel and vanadium in crude oil has been evaluated in several scientific studies because these elements can contribute to equipment corrosion, the contamination of catalytic processes, and environmental pollution. Many studies have focused on the evaluation of the total concentration of these elements. However, although it is important to know the total elemental concentration to determine the chemical composition of a sample, this does not yield information about the amount of potentially toxic compounds that may be associated with different macromolecules present in the sample. Here, we report the development of a sequential extraction procedure for the separation of nickel and vanadium species. To determine the total concentration of Ni and V, samples, as well as a certified reference material (NIST – SRM 1634C), were acid digested and analyzed by electrothermal atomic absorption spectrometry (ETAAS). The separation of the species was performed by column chromatography with silica gel as the stationary phase, and hexane (fraction 1), toluene (fraction 2), dichloromethane (DCM)?+?methanol (fraction 3), and methanol (fraction 4) as the eluents. The extracts obtained in each fraction were analyzed by ETAAS, gas chromatography–mass spectrometry (GC–MS), and infrared (IR) measurements. The experimental results showed that the total concentrations of the elements in the crude oil were between 7.4 and 14.3??g?g?1 for Ni and 9.8 to 14.6??g?g?1 for V. The analysis of SRM 1634C showed that 89% of Ni and 103% of V were recovered. The GC–MS analysis showed the following elution order: saturated compounds and aromatics (fraction 1), aromatic and cyclic compounds (fraction 2), aromatic compounds (fraction 3), and polar compounds (fraction 4). The results obtained by ETAAS showed that 100% of the Ni and V contained in crude oil can be separated in three different extracts. However, the IR spectra and GC–MS analysis allowed us to conclude that Ni and V are associated with compounds containing nitrogen and oxygen that were not identified by gas chromatography.Cavosie, A.J., Timms, N.E., Erickson, T.M., Koeberl, C., 2018. New clues from Earth’s most elusive impact crater: Evidence of reidite in Australasian tektites from Thailand. Geology 46, 203-206. tektites are enigmatic drops of siliceous impact melt found in an ～8000 × ～13,000 km strewn field over Southeast Asia and Australia, including sites in both the Indian and Pacific oceans. These tektites formed only 790,000 yr ago from an impact crater estimated to be 40–100 km in diameter; yet remarkably, the young and presumably large structure remains undiscovered. Here we report new evidence of a rare high-pressure phase in Australasian tektites that further constrains the location of the source crater. The former presence of reidite, a high-pressure polymorph of zircon, was detected in granular zircon grains within Muong Nong–type tektites from Thailand. The zircon grains are surrounded by tektite glass and are composed of micrometer-sized neoblasts that contain inclusions of ZrO2. Each grain consists of neoblasts in three distinct crystallographic orientations as measured by electron backscatter diffraction, where all [001] directions are orthogonal and aligned with one <110> direction from the other two orientations. The systematic orientation relationships among zircon neoblasts are a hallmark of the high-pressure polymorphic transformation to reidite and subsequent reversion to zircon. The preserved microstructures and dissociation of zircon to ZrO2 and SiO2 require a pressure >30 GPa and a temperature >1673 °C, which represent the most extreme conditions thus far reported for Australasian Muong Nong–type tektites. The data presented here place further constraints on the distribution of high-pressure phases in Australasian tektites, including coesite and now reidite, to an area centered over Southeast Asia, which appears to be the most likely location of the source crater.Caxito, F.A., Frei, R., Uhlein, G.J., Gon?alves Dias, T., ?rting, T.B., Uhlein, A., 2018. Multiproxy geochemical and isotope stratigraphy records of a Neoproterozoic Oxygenation Event in the Ediacaran Sete Lagoas cap carbonate, Bambuí Group, Brazil. Chemical Geology 481, 119-132. order to investigate the geochemical responses of Earth's oceans and atmosphere after a Snowball glaciation, we studied an Ediacaran cap carbonate profile pertaining to the base of the Bambuí Group (Sete Lagoas Formation) in the central portion of the S?o Francisco basin, east central Brazil, for trace elements (including REE?+?Y) and C, O, Sr, Nd, Pb and Cr isotopes. The section can be divided in three portions, from bottom to top: (i) a two-meter thick cap dolostone preserving a drop of δ13C values from ?3.8 to ?4.2‰, overlain by (ii) a ca. 123?meters-thick, reddish limestone rhythmite deposited in a tidal flat, with an important isotopic shift observed at 60?m, with δ13C values below averaging ?5‰ and above shifting abruptly to around ?0.5‰; and (iii) a topmost ca. 2?meters thick black calcarenite with positive δ13C (+0.9‰) and 87Sr/86Sr?=?0.7076. A new, tightly constrained Pb-Pb whole rock isochron of 608?±?19?Ma provides additional support for deposition during the early Ediacaran. We put forward a model for the deposition of the Sete Lagoas cap carbonate which starts with the glacial aftermath, when the thin cap dolostone and the basal reddish limestone were deposited due to glacier melting and subsequent sea level rise, with important mixing of glacial meltwaters with anoxic bottom waters. A decreasing trend of εNd(630Ma) values, from ?6 at the base to ca. ?8 at the 60?meters-mark, indicates continued input of continentally-derived detrital particles to the basin. During this phase, intermittent subaerial exposure was responsible for meteoric diagenetic alteration, which shifted 87Sr/86Sr to higher values (>0.710) and δ18O towards lower values. Towards the top of the sequence, the late postglacial succession is marked by marine-like REE?+?Y (Y/Ho?=?ca. 46) and lower Al and Mn contents, reflecting the diminishing of glacial meltwater input, a renewed sea level rise, and a change to more distal depositional environments, away from the coastal lines. At this moment, a vigorous input of U(VI) and 53Cr-rich Cr(VI), reflecting in a sharp rise of U/Th ratios and positive δ53Cr, suggests that fully oxygenated conditions finally predominated in post-glacial surface waters in the middle to late Ediacaran. Our results add to a growing body of data for other Ediacaran cap carbonate sequences around the world (e.g. Otavi Group, Namibia and Doushantuo Formation, China) that suggest that after ca 1?Ga of anoxia (the “Boring Billion”) following the first Great Oxygenation Event, the oceans became increasingly oxygenated after the end of the Marinoan glaciation ca. 635?Ma ago, ultimately leading to the explosion of complex macroscopic life that followed this Neoproterozoic Oxygenation Event.Chakravarthy, R., Paramati, M., Savalia, A., Verma, A., Das, A.K., Saravanan, C., Gudasi, K.B., 2018. Sulfur and total carboxylic acid number determination in vacuum gas oil by attenuated total reflectance Fourier transform infrared spectroscopy. Energy & Fuels 32, 2128–2136. removal is one of the key functions of vacuum gas oil (VGO) hydrotreating reactors. Knowing feed and product properties real-time or near-real-time improves reactor operations. The VGO section of crude distillation unit is also prone to severe high-temperature sulfidic and naphthenic acid corrosion. In this article, we evaluate a single-reflectance attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy as a possible quick and cost-effective methodology to determine total carboxylic acid number (TCAN) and total sulfur content of VGO. The study shows that single-reflectance diamond ATR crystal methodology has the right signal-to-noise ratio to accurately predict TCAN and total sulfur within the primary method’s repeatability. Statistical models have been developed using 64 sample sets of vacuum gas oil and out of which 10 samples were used for the cross-validation of the model. The range of TCAN in VGO samples used in this study was between 0.37 and 13.8 mg KOH/g, and sulfur content was between 0.8 to 5.4% by mass. Models have been evaluated by determining the correlation coefficient (R2), linearity curves obtained by plotting measured versus predicted values, and the errors associated with the prediction and cross-validation. The models showed a correlation coefficient of 0.9991 for TCAN and 0.9974 for total sulfur between reference and the measured values for calibration set of samples. A root-mean-square error of calibration (RMSEC) and prediction (RMSEP) for TCAN were found to be 0.0903 and 0.0885 mg KOH/g. Similarly, RMSEC and RMSEP values for sulfur content were 0.0829 and 0.107% by mass, respectively. The proposed methodology for the prediction of total sulfur and TCAN is fast, efficient, and cost-effective and has several advantages over the standard methods.Chance, R.J., Hamilton, J.F., Carpenter, L.J., Hackenberg, S.C., Andrews, S.J., Wilson, T.W., 2018. Water-soluble organic composition of the Arctic Sea surface microlayer and association with ice nucleation ability. Environmental Science & Technology 52, 1817-1826. matter in the sea surface microlayer (SML) may be transferred to the atmosphere as sea spray and hence influence the composition and properties of marine aerosol. Recent work has demonstrated that the SML contains material capable of heterogeneously nucleating ice, but the nature of this material remains largely unknown. Water-soluble organic matter was extracted from SML and underlying seawater from the Arctic and analyzed using a combination of mass spectrometric approaches. High performance liquid chromatography-ion trap mass spectrometry (LC-IT-MS), and Fourier transform ion cyclotron resonance MS (FT-ICR-MS), showed seawater extracts to be compositionally similar across all stations, whereas microlayer extracts had a different and more variable composition. LC-IT-MS demonstrated the enrichment of particular ions in the microlayer. Ice nucleation ability (defined as the median droplet freezing temperature) appeared to be related to the relative abundances of some ions, although the extracts themselves did not retain this property. Molecular formulas were assigned using LC-quadrupole time-of-flight MS (LC-TOF-MS2) and FT-ICR-MS. The ice nucleation tracer ions were associated with elevated biogenic trace gases, and were also observed in atmospheric aerosol collected during the summer, but not early spring suggesting a biogenic source of ice nuclei in the Arctic microlayer.Chang, X., Liang, J., Cui, J., Wang, T., 2018. Geochemical characterization of alteration of saturate fractions by water flooding. Acta Sedimentologica Sinica 36, 206-214. on the GC and GC-MS analysis, modification of saturate fractions in waterflooded oils from Qu9 reservoir was dynamically investigated. The results indicate that with the advance of waterflooding, saturates characterize obvious alterations during 9-months dynamic surveillance. Saturate concentration, C15-RD/C15-D, C158β(H)-D/C168β(H)-HD, TTs/17α-H and RS/17α-H ratios, are progressively increasing in values. Aromatic concentration∑nC21-/∑nC22+ and ∑nC14-/∑nC15+reduce continually. Isoalkane related ratios of Pr/Ph, iC18/Pr, iC18/Ph, terpane related ratios of C21/C22TT, C24/C23TT, ∑C19-26/∑C28-29TTs, C30*/C29Ts, C35R/C34R, Ol/C30H, G/C31R, C3122S/(22S+22R), C30M/C30H, Ts/(Ts+Tm) and C29Ts/(C29Ts+C29H), and sterane related ratios of C27-DS/C27-RS, C2920S/(20S+20R), C29ββ/(ββ+αα) and C27-rearranged sterane 20S/(20S+20R), keep relatively unchanged. However, irregular variation of Pr/nC17 and Ph/nC18 shows an initial increase and subsequent decrease, or the opposite. Water washing leads to the decrease of aromatics and light/heavy alkane values, while the biodegradation results in the concentration of tricyclic terpanes and regular sterane compared to the hopanes. Although they have minor effect on the ratios respectively composed of two isoalkanes, terpanes and steranes with similar carbon numbers, they cause the increase of drimane parameters in combination. Mixed with the geo-chromatography and wettability transformation in water flooding, saturates compositions were further altered.Chang, Z., Chu, M., Zhang, C., Bai, S., Lin, H., Ma, L., 2018. Influence of inherent mineral matrix on the product yield and characterization from Huadian oil shale pyrolysis. Journal of Analytical and Applied Pyrolysis 130, 269-276. oil shale was subjected to step-wise acid treatment to remove inherent carbonate and silicate minerals. The original oil shale and its demineralization products (carbonate- and carbonate-silicate-free oil shale samples) were pyrolyzed in a fixed-bed pyrolyzer to determine the mineral matrix effect on product yield and characteristics of shale oil and gases. The shale oil yields of original, carbonate-free, and carbonate-silicate-free oil shale samples were 50.4?wt.%, 44.3?wt.%, and 50.3?wt.% (values on dry and mineral matter-free basis), respectively, which indicated that carbonates promote, while silicates suppress, shale oil production. Coking of aromatic compounds appeared to be the dominant mechanism accounting for the variation of the shale oil yield. Elimination of the carbonate minerals decreased the nitrogen- and oxygen-containing compounds of shale oil, while removal of silicates increased the oxygenated compounds. Both carbonate and silicate minerals decreased the atomic H/C ratio of shale oil. Silicates promoted the cracking and aromatization of aliphatic hydrocarbons, which increased the short-chain aliphatic hydrocarbons and aromatic hydrocarbons of shale oil, as well as C1–C4 hydrocarbons and H2 yields. On the contrary, carbonates suppressed the cracking of long chain aliphatic hydrocarbons.Chang, Z., Tian, L., Li, F., Zhou, Y., Wu, M., Steinberg, C.E.W., Dong, X., Pan, B., Xing, B., 2018. Benzene polycarboxylic acid — A useful marker for condensed organic matter, but not for only pyrogenic black carbon. Science of The Total Environment 626, 660-667. polycarboxylic acid (BPCA) molecules are a widely used marker method for the qualitative and quantitative analysis of pyrogenic black carbons (BC). Based on an overview of the development and chemical reaction mechanism of the BPCA method, we propose that the commonly used BPCA markers may not be solely indicative of BC but more generally of condensed organic matter in soils and aquatic systems. First, we sequentially removed the soil fractions and observed that the BPCA contents were abundant in humic acids (HAs). After sequential treatment, the residual particles were supposed to contain BC and minerals; however, the BPCAs in the residue accounted for only 2.4–10.1% of that detected in the entire soil. In addition, substantial quantities of BPCAs were detected in both thermally treated samples and composted biomass. Furthermore, humic acids extracted from all the samples showed that obvious BPCA contents in the samples accounted for 0.1–121.7?mg/g. Therefore, soil fractionation may also partly extract BCs as suggested by BPCAs in the HAs of the biochars. However, organic matter without any thermal treatment may contain BPCAs. A series of standard substances without any BC showed high BPCA content in the samples from 5.9–124.5?mg/g. These observations create a serious concern for the proper application of BPCAs as a marker for BCs. Combining a systematic literature review of BPCA that deviates from BC content, we suggest that the BC-like structure of organic matter may be referred to as BPCA-probed organic matter content, which could be a more useful term for studies on the multimedia environmental behaviors of contaminants.Chang, Z., Zhang, W., Ge, X., Zhu, S., 2018. Use of light hydrocarbons for the oil-oil correlation in Pearl River Mouth Basin, South China Sea. Fuel 221, 179-187. composition of 28 oil samples from Wenchang and Enping formations of Pearl River Mouth Basin (PRMB) was characterized and emphasis was placed on compositional variations in the gasoline range (i-C5H12-n-C8H18). The light hydrocarbons (LHs) were sensitively determined by gas purge microsyringe extraction (GP-MSE) coupled with gas chromatography-mass spectrometry (GC–MS) and GC-flame ionization detector (FID), respectively. According to the relative concentration of LHs, the Mango’s K1 parameter was calculated and a cross plot was obtained. Invariance in the K1 ratio was observed with a correlation coefficient approximately equal to 1 for all the studied crude oils, however, the absolute K1 values were different for each oil family, which indicates the distinct genetic features. Furthermore, several LH indicators were screened and a model was developed for correlating oils using LHs combined with multivariate statistical method. To validate the model, the correlation results based on routine biomarkers and LHs were compared by using normal oil samples, and consistent conclusions were achieved. As alternative to routine biomarkers, LHs show good potential in geochemical correlation of crude oils, especially when routine biomarkers are absent or at very low concentration in high maturated oil samples.Chaudhary, D.K., Kim, J., 2018. Sphingobacterium terrae sp. nov., isolated from oil-contaminated soil. International Journal of Systematic and Evolutionary Microbiology 68, 609-615. cream-coloured, Gram-stain-negative, non-motile and rod-shaped bacterium, designated strain Brt-FT, was isolated from oil-contaminated soil. Strain Brt-FT was able to grow from 15 to 45?°C, pH 6.5–10.5 and 0–4.5?% (w/v) NaCl concentration. This strain was taxonomically characterized by a polyphasic approach. Based on 16S rRNA gene sequence analysis, strain Brt-FT represented a member of the genus Sphingobacterium and shared highest sequence similarity with Sphingobacterium chuzhouense DH-5T (99.4?%); Sphingobacterium gobiense H7T (95.7?%) and Sphingobacterium arenae H-12T (94.3?%). The only respiratory quinone was menaquinone-7, the major polar lipid was phosphatidylethanolamine and the predominant fatty acids were summed feature 3 (C16?:?1ω7c and/or C16?:?1ω6c), iso-C15?:?0, and iso-C17?:?0 3-OH. The DNA G+C?content was 43.4?mol%. The DNA–DNA relatedness value between strain Brt-FT and S. chuzhouense KCTC 42746T was 35.7?%, which falls below the threshold value of 70?% for the strain to be considered as novel. The morphological, physiological, chemotaxonomic and phylogenetic analyses clearly distinguished this strain from its closest phylogenetic neighbours. Thus, strain Brt-FT represents a novel species of the genus Sphingobacterium , for which the name Sphingobacterium terrae sp. nov. is proposed. The type strain is Brt-FT (=KEMB 9005-691T=KACC 19392T=JCM 32159T). The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain Brt-FT is MF405100.Chaudhary, D.K., Kim, J., 2018. Tessaracoccus terricola sp. nov., isolated from oil-contaminated soil. International Journal of Systematic and Evolutionary Microbiology 68, 529-535. Gram-stain-positive, non-motile, yellow and rod-shaped actinobacterium, designated strain Brt-AT, isolated from oil-contaminated soil, grew at 15–40?°C, at pH 5.5–10.0 and at 0–2?% (w/v) NaCl concentration. This strain was characterized by a polyphasic approach. The 16S rRNA gene sequence analysis showed that strain Brt-AT belonged to the genus Tessaracoccus and is closely related to Tessaracoccus rhinocerotis YIM 101269T, Tessaracoccus flavescens SST-39T, Tessaracoccus defluvii LNB-140T and Tessaracoccus flavus RP1T (99.03, 97.00, 96.88, and 96.46?% gene sequence similarity, respectively). The predominant respiratory quinone was MK-9(H4); the major polar lipids were phosphatidylglycerol and diphosphatidylglycerol; the predominant polyamines were spermine and spermidine; and the major fatty acids were anteiso-C15?:?0 and iso-C15?:?0. The cell-wall peptidoglycan contained ll-diaminopimelic acid; and glucose and ribose were detected as diagnostic sugars from whole-cell hydrolysates. The DNA G+C?content was 68.1?mol%. The DNA–DNA relatedness between strain Brt-AT and its closely related species of the genus Tessaracoccus were between 55.0–44.0?%, which fall below the threshold value of 70?% for the strain to be considered as novel. The morphological, physiological, chemotaxonomic and phylogenetic analyses clearly distinguished this strain from its closest phylogenetic neighbours. Thus, strain Brt-AT represents a novel species of the genus Tessaracoccus , for which the name Tessaracoccus terricola sp. nov. is proposed. The type strain is Brt-AT (=KEMB 9005-690T=KACC 19391T=JCM 32157T). The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain Brt-AT is MF405099.Chen, B., OuYang, C., Tian, Z., Xu, M., Li, L., 2018. A high resolution atmospheric pressure matrix-assisted laser desorption/ionization-quadrupole-Orbitrap MS platform enables in situ analysis of biomolecules by multi-mode ionization and acquisition. Analytica Chimica Acta 1007, 16-25. in 2000, atmospheric pressure (AP)/matrix-assisted laser desorption/ionization (MALDI) has attracted substantial attention in the mass spectrometry community due to its ease of sample introduction and handling, interchangeability with ESI source and capability of analyzing volatile species. In this study, an AP/MALDI source with ultra-high spatial resolution was coupled to a Q Exactive HF orbitrap mass spectrometer for high resolution in situ analysis by MALDI, laserspray ionization (LSI) and matrix assisted ionization (MAI) without instrument modification. LSI and MAI generated multiply charged ions, which expanded the mass detection range and improved fragmentation efficiency. Full MS, targeted MS/MS, data dependent acquisition (DDA) and (PRM) acquisitions were performed on peptide and protein standards, tissue extracts and tissue sections for in depth characterization of various biomolecules. High resolution full MS and MS/MS images were obtained from crustacean and rat tissues with pixel size less than 30?μm. Overall, AP/MALDI-Q-Orbitrap is a fast scanning instrument that is capable of performing multiple types of ionization and multiple acquisition modes without instrument modification. This instrument platform provides an attractive alternative to other high resolution MALDI instruments.Chen, G., Gang, W.Z., Wang, N., Zhao, L.Y., 2018. Geochemical characterisation of the Xiagou Formation carbonate-bearing mudstone in southwestern Jiuquan Basin, China: implications for paleo-environment reconstruction and the origin of organic matter. Australian Journal of Earth Sciences 65, 121-134. the Xiagou Formation was confirmed to be the primary source rock of the crude oil discovered in the Yumen oilfield, geologists have performed many studies on the sedimentology of the formation, source rock evaluation and migration, as well as petroleum accumulation. In this study, the carbonate-bearing mudstones were investigated using synthetic organic and inorganic geochemical analyses to reconstruct the paleo-environment and study the origin of organic matter during deposition in correlation with organic matter enrichment. The analysed samples have total organic carbon (TOC) and S1 + S2 values in the range of 0.20–3.39 wt% and 0.07–19.50%, respectively, which indicate fair to good hydrocarbon potential. Biomarker studies on the pyrolysis data of the samples suggest that the predominant origin of the organic matter is terrigenous high plants with partial aquatic algae and micro-organisms, primarily oil- and gas-prone. The trace elements P and Ba are considered to be the main proxies for paleoproductivity, and values for the two elements hosted in samples range from 48 to 1724 ppm (a mean of 658 ppm) and from 322 to 1701 ppm (a mean of 550.34 ppm), respectively, which indicates that the sediments in the Xiagou Formation have high paleoproductivity. Additionally, organic geochemical studies reveal that the sediments were deposited in a lacustrine environment with brackish water (low C31-22R-homohopane/C30-hopane ratios; moderate gammacerane and β-carotane), which is consistent with the medium degree of the Sr/Ba ratio, which ranges from 0.22 to 1.42 (a mean of 0.64). Furthermore, the wide range of Cu/Zn and Rb contents are important indicators of a suboxic to relatively anoxic paleoredox condition. This outcome is consistent with the biomarker parameter Pr/Ph, which ranges from 0.05 to 1.37. Moreover, the major oxides and trace elements [high Fe/Mn, low Mg/Ca, low CIA and the plot of SiO2 vs (Al2O3 + K2O + Na2O)] also indicate that the sedimentary paleoclimate was semiarid to arid. Lack of correlation between TOC content and paleo-environment (suboxic, brackish and semiarid) or productivity indicators indicates that the accumulation of organic matter was controlled by combined action, rather than a single factor, such as redox condition or productivity.Chen, G., Lin, J., Hu, W., Cheng, C., Gu, X., Du, W., Zhang, J., Qu, C., 2018. Characteristics of a crude oil composition and its in situ waxing inhibition behavior. Fuel 218, 213-217. crude oil containing high paraffin from Yanchang Oilfield was studied for the situ waxing inhibition as an example in this work. The components were separated using silica gel column chromatography by different eluent and were named A1 to A14, and the characteristics of each component and their influence on wax crystallization were studied. It was found that the separated components could interact with each other to decrease the temperature of the wax point to 0.2–1.64?°C, but the effect on the amount of wax was relatively small. Polarized micrographs showed that the components also affect the morphology and distribution of the wax crystals. For example, the component A5 make the wax crystals of A1 larger and make the distribution of wax crystals in a certain direction and more dispersed.Chen, J., Hu, P., Li, X., Yang, Y., Song, J., Li, X., Yuan, H., Li, N., Lü, X., 2018. Impact of water depth on the distribution of iGDGTs in the surface sediments from the northern South China Sea: applicability of TEX86 in marginal seas. Frontiers of Earth Science 12, 95-107. TEX86H paleothermometer on the base of isoprenoid glycerol dialkyl glycerol tetraethers (iGDGTs) has been widely applied to various marine settings to reconstruct past sea surface temperatures (SSTs). However, it remains uncertain how well this proxy reconstructs SSTs in marginal seas. In this study, we analyze the environmental factors governing distribution of iGDGTs in surface sediments to assess the applicability of TEX86H paleothermometer in the South China Sea (SCS). Individual iGDGT concentrations increase gradually eastwards. Redundancy analysis based on the relative abundance of an individual iGDGT compound and environmental parameters suggests that water depth is the most influential factor to the distribution of iGDGTs, because thaumarchaeota communities are water-depth dependent. Interestingly, the SST difference (ΔT) between TEX86H derived temperature and remote-sensing SST is less than 1°C in sediments with water depth>200 m, indicating that TEX86H was the robust proxy to trace the paleo-SST in the region if water depth is greater than 200 m.Chen, J., Pang, X., Pang, H., Chen, Z., Jiang, C., 2018. Hydrocarbon evaporative loss evaluation of lacustrine shale oil based on mass balance method: Permian Lucaogou Formation in Jimusaer Depression, Junggar Basin. Marine and Petroleum Geology 91, 422-431. evaporative loss evaluation is important for shale oil resource assessment. We propose a mass balance model to evaluate the hydrocarbon evaporative loss (S1-loss) in this study. The proposed method is applied to a large Rock-Eval pyrolysis dataset on source rock samples from the Lucaogou Formation in the Jimusaer Depression of the Junggar Basin, NW China, as a case study to evaluate the S1-loss. The results indicate that the S1-loss can range from 0.12 to 7.25?mg/g Rock, corresponding to 11%–89% loss of the generated hydrocarbons (S1-loss/(S1+S1-loss)) due to evaporation before lab analysis. It appears that when Ro?≤?1.3%, S1-loss and S1-loss/TOC decreases gradually with increasing Ro, likely corresponding to increasing oil density as results of heterogeneous source rock compositions and increased accommodation space via the creation of organic pores of large specific surface for heavy and large hydrocarbon molecules in oil window. When Ro > 1.3%, S1-loss/TOC begins to increase with increasing Ro as more oil crack to gaseous and light hydrocarbons that are more susceptible to evaporative loss. In the case of similar Ro, the relative S1-loss/TOC varies little among the samples but the absolute S1-loss amount increases with increasing TOC. Restricted by regional geological conditions in this study, we focused on the S1-loss for lacustrine type I kerogen only, and quantification of evaporative loss for other kerogen types remains a subject for further study.Chen, L., Meyer, J., Campbell, T., Canas, J., Betancourt, S.S., Dumont, H., Forsythe, J.C., Mehay, S., Kimball, S., Hall, D.L., Nighswander, J., Peters, K.E., Zuo, J.Y., Mullins, O.C., 2018. Applicability of simple asphaltene thermodynamics for asphaltene gradients in oilfield reservoirs: The Flory-Huggins-Zuo Equation of State with the Yen-Mullins model. Fuel 221, 216-232. recent years, the Flory-Huggins-Zuo Equation of State (FHZ EoS) has been utilized to treat asphaltene gradient data in many oilfield reservoirs. The FHZ EoS employs asphaltene species from the Yen-Mullins model consisting of molecules, nanoaggregates and clusters of nanoaggregates; the specific species used depends primarily on the concentration of asphaltenes but also on the asphaltene stability. Reservoirs with equilibrated asphaltenes are repeatedly found to produce oil as a single flow unit addressing a key reservoir property. For crude oils with moderate concentrations of asphaltenes (a few%), asphaltenes are typically dispersed as nanoaggregates. In crude oils with high concentrations of asphaltenes (～10%), asphaltenes are typically dispersed as clusters of nanoaggregates. This paper examines a reservoir with a crude oil of moderate concentration of asphaltenes where a secondary charge of methane created some limited instability of asphaltenes. Many pressure and fluid measurements are made to determine that indeed the fluid column is equilibrated. The FHZ EoS and the Yen-Mullins model in this equilibrated oil column are then compared with the asphaltene gradient; excellent agreement is obtained extending the use of this thermodynamic modeling to crude oils with limited asphaltene instability. Downhole fluid analysis (DFA) is used to delineate the asphaltene gradient, and both DFA and lab data are used for determination of solution gas content of oil samples. Conventional gas chromatography, two-dimensional gas chromatography (GC?×?GC) and gas isotope analysis are performed to analyze the oils, all with a focus to test and ensure thermodynamic equilibrium of the oil column. The mixed charge of an oil and a secondary gas is confirmed identifying the source of asphaltene instability. The result of the asphaltene instability is to create a fraction of crude oil at the base of the oil column with asphaltenes dispersed as clusters of asphaltenes, thus exhibiting a larger asphaltene gradient there. Fluid inclusion measurements are useful to indicate the sequence of events in gas and oil charging into the reservoirs in geologic time. The Flory-Huggins-Zuo EoS and the Yen-Mullins model continue to be confirmed in oilfield studies as well as in the laboratory, even in cases of limited asphaltene instability observed here.Chen, X., Verma, R., Espinoza, D.N., Prodanovi?, M., 2018. Pore-scale determination of gas relative permeability in hydrate-bearing sediments using X-ray computed micro-tomography and lattice Boltzmann method. Water Resources Research 54, 600-608. work uses X-ray computed micro-tomography (μCT) to monitor xenon hydrate growth in a sandpack under the excess gas condition. The μCT images give pore-scale hydrate distribution and pore habit in space and time. We use the lattice Boltzmann method to calculate gas relative permeability (krg) as a function of hydrate saturation (Shyd) in the pore structure of the experimental hydrate-bearing sand retrieved from μCT data. The results suggest the krg - Shyd data fit well a new model krg?=?(1-Shyd)·exp(–4.95·Shyd) rather than the simple Corey model. In addition, we calculate krg-Shyd curves using digital models of hydrate-bearing sand based on idealized grain-attaching, coarse pore-filling, and dispersed pore-filling hydrate habits. Our pore-scale measurements and modeling show that the krg-Shyd curves are similar regardless of whether hydrate crystals develop grain-attaching or coarse pore-filling habits. The dispersed pore filling habit exhibits much lower gas relative permeability than the other two, but it is not observed in the experiment and not compatible with Ostwald ripening mechanisms. We find that a single grain-shape factor can be used in the Carman-Kozeny equation to calculate krg-Shyd data with known porosity and average grain diameter, suggesting it is a useful model for hydrate-bearing sand.Chen, X., Zhao, Y., Liu, L., Zhang, L., Zhang, Z., Qiu, P., 2018. Evaluation of chemical structure, pyrolysis reactivity and gaseous products of Shenmu coal of different particle sizes. Journal of Analytical and Applied Pyrolysis 130, 294-304. this study, chemical structure and pyrolysis reactivity of six different coal particle fractions were researched using Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA), respectively. An on-line FTIR was applied to assess the evolution characteristics of the gaseous products. The results expose that with the particle size decreasing, the ash content of Shenmu coal sample gradually increases, while the pyrolysis reactivity steadily decreases. In addition, the content of hydrogen as well as some typical chemical groups in coal is also affected by particle size. In our experimental conditions, the comprehensive infrared structural parameter has a good linear relation with pyrolysis reactivity. Moreover, with the particle size decreasing, the release amount of CH4, aliphatic hydrocarbons and light aromatic hydrocarbons gradually decreases, while the release amount of CO changes little.Chibiryaev, A.M., Kozhevnikov, I.V., Shalygin, A.S., Martyanov, O.N., 2018. Transformation of petroleum asphaltenes in supercritical alcohols studied via FTIR and NMR techniques. Energy & Fuels 32, 2117-2127. aliphatic alcohols (methanol, ethanol, and 1- and 2-propanols) were used for the first time as a reaction media for the upgrading of crude oil asphaltenes. The process was realized in a batch reactor under supercritical conditions (at 350 °C). The three main fractions of the products (hexane- and benzene-soluble fractions, HSF and BSF, and insoluble residue, IR) were analyzed using attenuated total reflection Fourier tranform infrared (ATR-FTIR) and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy to characterize structural changes of the initial asphaltenes (IA). According to NMR data, the aliphatics are the main part of the hexane-soluble fraction (HSF) and benzene-soluble fraction (BSF). The alcohols were appeared to influence the content of both aliphatics and aromatics in the products. The content of aliphatics in the HSF increases in the line from “lighter” to “heavier” alcohols used but reduces in the BSF. However, the content of aromatics in the HSF increases from “heavier” to “lighter” alcohols, while this order is reversed for the BSF. According to the ATR-FTIR spectroscopy data, the aromatics-to-aliphatics ratios observed for the insoluble residues are 2–3 times higher as compared with the initial asphaltenes but 2 times lower for the HSF. The BSF are composed of less-condensed aromatics than those of the IA. It is shown that the alcohols used as a reaction media are incorporated in the product molecules as alkoxy substituents in aromatic ethers Ar–OAlk. According to NMR and ATR-FTIR data obtained, the alkylation–dealkylation and alkoxylation reactions make a crucial contribution to the chemical transformations of the asphaltenes.Chistoserdova, L., 2018. Applications of methylotrophs: can single carbon be harnessed for biotechnology? Current Opinion in Biotechnology 50, 189-194. review summarizes developments in the field of applied research involving microbial conversion of single carbon compounds (methane, methanol, CO2). The potential of the microorganisms involved in biotechnological applications could be realized via engineering native C1 utilizers toward higher output of value-added compounds, including biofuels, or via production of value chemicals as parts of novel, heterologously expressed biochemical pathways. Alternatively, C1 metabolism could be implemented in traditional industrial platforms (Escherichia coli, yeast), via introduction of specific metabolic modules. Most recent research spanning both approaches is covered. The potential of C1 utilizers in biomining of rare Earth elements, as well as the potential of C1 consuming microbial consortia in industrial applications are discussed.Cione, A.L., Santillana, S., Gouiric-Cavalli, S., Acosta Hospitaleche, C., Gelfo, J.N., López, G.M., Reguero, M., 2018. Before and after the K/Pg extinction in West Antarctica: New marine fish records from Marambio (Seymour) Island. Cretaceous Research 85, 250-265. ichthyofauna recovered from the López de Bertodano Formation at Units 9 (uppermost Maastrichtian) and 10 (lowermost Danian) and the Sobral Formation (Danian), in Marambio (Seymour) Island in the James Ross Basin is described and analyzed herein. A review of previously described taxa based on the new material and several new fish records for the López de Bertodano Formation is provided, including the youngest record of Enchodus and the first Cretaceous evidence of Pachycormiformes. We also identify the first Paleocene fishes for the continent. The new information and the reinterpretation of previous Cretaceous records show that there was no decline in fish diversity until the Cretaceous–Paleogene (K/Pg) boundary in the area and extinction event appears to have been rapid. Finally, we find that the distribution of some chondrichthyans and teleosts in the James Ross Basin appears to be climatically determined.Cloutis, E.A., Pietrasz, V.B., Kiddell, C., Izawa, M.R.M., Vernazza, P., Burbine, T.H., DeMeo, F., Tait, K.T., Bell III, J.F., Mann, P., Applin, D.M., Reddy, V., 2018. Spectral reflectance “deconstruction” of the Murchison CM2 carbonaceous chondrite and implications for spectroscopic investigations of dark asteroids. Icarus 305, 203-224. chondrites (CCs) are important materials for understanding the early evolution of the solar system and delivery of volatiles and organic material to the early Earth. Presumed CC-like asteroids are also the targets of two current sample return missions: OSIRIS-REx to asteroid Bennu and Hayabusa-2 to asteroid Ryugu, and the Dawn orbital mission at asteroid Ceres. To improve our ability to identify and characterize CM2 CC-type parent bodies, we have examined how factors such as particle size, particle packing, and viewing geometry affect reflectance spectra of the Murchison CM2 CC. The derived relationships have implications for disc-resolved examinations of dark asteroids and sampleability. It has been found that reflectance spectra of slabs are more blue-sloped (reflectance decreasing toward longer wavelengths as measured by the 1.8/0.6??m reflectance ratio), and generally darker, than powdered sample spectra. Decreasing the maximum grain size of a powdered sample results in progressively brighter and more red-sloped spectra. Decreasing the average grain size of a powdered sample results in a decrease in diagnostic absorption band depths, and redder and brighter spectra. Decreasing porosity of powders and variations in surface texture result in spectral changes that may be different as a function of viewing geometry. Increasing thickness of loose dust on a denser powdered substrate leads to a decrease in absorption band depths. Changes in viewing geometry lead to different changes in spectral metrics depending on whether the spectra are acquired in backscatter or forward-scatter geometries. In backscattered geometry, increasing phase angle leads to an initial increase and then decrease in spectral slope, and a general decrease in visible region reflectance and absorption band depths, and frequent decreases in absorption band minima positions. In forward scattering geometry, increasing phase angle leads to small non-systematic changes in spectral slope, and general decreases in visible region reflectance, and absorption band depths. The highest albedos and larger band depths are generally seen in the lowest phase angle backscattering geometry spectra. The reddest spectra are generally seen in the lowest phase angle backscatter geometry spectra. For the same phase angle, spectra acquired in forward scatter geometry are generally redder and darker and have shallower absorption bands than those acquired in backscatter geometry. Overall, backscatter geometry-acquired spectra are flatter, brighter, and have deeper 0.7??m region absorption band depths than forward scatter geometry-acquired spectra. It was also found that the 0.7, 0.9, and 1.1??m absorption bands in Murchison spectra, which are attributable to various Fe electronic processes, are ubiquitous and can be used to recognize CM2 chondrites regardless of the physical properties of the meteorite and viewing geometry.Cockell, C.S., Biller, B., Bryce, C., Cousins, C., Direito, S., Forgan, D., Fox-Powell, M., Harrison, J., Landenmark, H., Nixon, S., Payler, S.J., Rice, K., Samuels, T., Schwendner, P., Stevens, A., Nicholson, N., Wadsworth, J., 2018. The UK Centre for Astrobiology: A virtual astrobiology centre. Accomplishments and lessons learned, 2011–2016. Astrobiology 18, 224-243. UK Centre for Astrobiology (UKCA) was set up in 2011 as a virtual center to contribute to astrobiology research, education, and outreach. After 5 years, we describe this center and its work in each of these areas. Its research has focused on studying life in extreme environments, the limits of life on Earth, and implications for habitability elsewhere. Among its research infrastructure projects, UKCA has assembled an underground astrobiology laboratory that has hosted a deep subsurface planetary analog program, and it has developed new flow-through systems to study extraterrestrial aqueous environments. UKCA has used this research backdrop to develop education programs in astrobiology, including a massive open online course in astrobiology that has attracted over 120,000 students, a teacher training program, and an initiative to take astrobiology into prisons. In this paper, we review these activities and others with a particular focus on providing lessons to others who may consider setting up an astrobiology center, institute, or science facility. We discuss experience in integrating astrobiology research into teaching and education activities.Coutinho, D.M., Fran?a, D., Vanini, G., Mendes, L.A.N., Gomes, A.O., Pereira, V.B., ?vila, B.M.F., Azevedo, D.A., 2018. Rapid hydrocarbon group-type semi-quantification in crude oils by comprehensive two-dimensional gas chromatography. Fuel 220, 379-388. is the main source of energy used in the world. The oil industry faces challenges in trying to understand the chemical composition of crude oils, quantitatively and qualitatively. The application of specific and sophisticated techniques allows a detailed characterization and provides important information that impacts from the exploration to production, transportation, and crude oil refining. A set of twelve crude oil samples with different API gravity were analyzed via comprehensive two-dimensional (2D) gas chromatography coupled to time-of-flight mass spectrometry (GC?×?GC-TOFMS) aimed at the detection, identification and semi-quantification of hydrocarbon classes using extracted ion chromatogram (EIC) and total ion chromatogram (TIC). The use of the polar/non-polar column configuration provided better separation between the hydrocarbon classes which allowed the identification and semi-quantification of the same. Therefore, series of n- and iso-alkanes, alkyl-cyclohexanes, alkyl-cyclopentanes, alkyl-decalines, alkyl-naphthalenes, alkyl-phenanthrenes and alkyl-9H-fluorenes were characterized. In the present study, a semi-quantification approach to data assessment using TIC is proposed. Comprehensive evaluation provided the chromatographic fingerprint of each sample in a single analysis followed by the semi-quantification of the hydrocarbon classes. The oil samples presented completely different hydrocarbon class data, even when presenting similar API gravity values. Branched alkanes and n-alkanes were the major semi-quantified compounds, and branched alkane concentrations were higher than n-alkanes in the majority of samples. These results afford valuable information for the petrochemical industry. GC?×?GC-TOFMS was applied for speciation and group-type semi-quantification using a single oil drop without a fractionation or clean up step.Coward, A.J., Mays, C., Patti, A.F., Stilwell, J.D., O'Dell, L.A., Viegas, P., 2018. Taphonomy and chemotaxonomy of Eocene amber from southeastern Australia. Organic Geochemistry 118, 103-115. is a complex, organic polymer that offers unparalleled utility as a preservation medium, providing insights into past organisms and environments. However, under specific circumstances, this information can be compromised through alteration of the amber structure. Understanding the degradation of amber in the geosphere could improve prospecting techniques and maximise the quality and validity of chemical information from altered samples. This study analysed 114 amber samples retrieved from two new Eocene Australian deposits at Strahan, Tasmania and Anglesea, Victoria using a combination of attenuated total reflectance Fourier transform infrared and solid-state 13C cross-polarised magic angle spinning nuclear magnetic resonance spectroscopy. Results identified both Class Ib polylabdanoid and Class II cadinene-based amber. The presence of Class II amber in Australia suggests one of two possibilities: (1) a local Dipterocarpaceae source, the primary producer of Class II resins, despite the absence of this family from the Australian Eocene fossil record; or (2) a local, unidentified botanical source of cadinene-based amber. A third alternative, that Class II amber was transported to Australia from Southeast Asia via ocean currents, is rejected. Taphonomic analysis revealed four mechanisms of alteration prevalent in amber across the two study regions, with evidence of oxidation and metal carboxylate formation. Both the nature and extent of these alterations were found to vary significantly between classes I and II, suggesting that amber class may play a defining role in determining the chemical pathways by which amber degrades. Of note was the high proportion of amber that exhibited no significant chemical changes despite extensive visible alteration features, suggesting the integrity of palaeobiological and palaeoenvironmental information in these samples may be preserved.Coward, E.K., Ohno, T., Plante, A.F., 2018. Adsorption and molecular fractionation of dissolved organic matter on iron-bearing mineral matrices of varying crystallinity. Environmental Science & Technology 52, 1036-1044. (Fe)-bearing mineral phases contribute disproportionately to adsorption of soil organic matter (SOM) due to their elevated chemical reactivity and specific surface area (SSA). However, the spectrum of Fe solid-phase speciation present in oxidation–reduction-active soils challenges analysis of SOM–mineral interactions and may induce differential molecular fractionation of dissolved organic matter (DOM). This work used paired selective dissolution experiments and batch sorption of postextraction residues to (1) quantify the contributions of Fe-bearing minerals of varying crystallinity to DOM sorption, and (2) characterize molecular fractionation using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). A substantial proportion of soil SSA was derived from extracted Fe-bearing phases, and FT-ICR-MS analysis of extracted DOM revealed distinct chemical signatures across Fe-OM associations. Sorbed carbon (C) was highly correlated with Fe concentrations, suggesting that Fe-bearing phases are strong drivers of sorption in these soils. Molecular fractionation was observed across treatments, particularly those dominated by short-range-order (SRO) mineral phases, which preferentially adsorbed aromatic and lignin-like formulas, and higher-crystallinity phases, associated with aliphatic DOM. These findings suggest Fe speciation-mediated complexation acts as a physicochemical filter of DOM moving through the critical zone, an important observation as predicted changes in precipitation may dynamically alter Fe crystallinity and C stability.Cui, C., Billa, T., Zhang, L., Shi, Q., Zhao, S., Klein, M.T., Xu, C., 2018. Molecular representation of the petroleum gasoline fraction. Energy & Fuels 32, 1525-1533. computer-aided reconstruction of gasoline composition is an active area of petroleum and petrochemical research as a result of the demand for molecular-level management of the petroleum feed streams. To that end, in this work, a molecular compositional model based on a predefined representative molecular set was built that allows for the conversion of conventional bulk property data to an approximate molecular composition. The selection of representative molecules was based on their presence in gasoline molecular compositional measurement and their potential contribution to the key physical properties. Around 170 hydrocarbons and heteroatom species were chosen as predefined identities of molecules that can exist in a gasoline sample. The physical property data of all of the representative molecules were collected, and suitable mixing rules for the gasoline range stream were applied for the accurate prediction of bulk properties. The approximate concentration of representative molecules was obtained through fitting the predicted bulk property to the measured data. The methodology was verified through intensive tests on various gasoline samples, including straight-run naphtha, catalytic cracking gasoline, coking gasoline, and reformates. The modeling was also accomplished in a sequential order using basic to advanced measurements to find the optimum number of measurements required for detailed composition evaluation on various feedstocks. The propagation of error in the experimental measurement and prediction method on composition has been evaluated.Cui, C., Fearn, T., 2018. Hierarchical mixture of linear regressions for multivariate spectroscopic calibration: An application for NIR calibration. Chemometrics and Intelligent Laboratory Systems 174, 1-14. paper investigates the use of the hierarchical mixture of linear regressions (HMLR) and variational inference for multivariate spectroscopic calibration. The performance of HMLR is compared to the classical methods: partial least squares regression (PLSR), and PLS embedded locally weighted regression (LWR) on three different NIR datasets, including a publicly accessible one. In these tests, HMLR outperformed the other two benchmark methods. Compared to LWR, HMLR is parametric, which makes it interpretable and easy to use. In addition, HMLR provides a novel calibration scheme to build a two-tier PLS regression model automatically. This is especially useful when the investigated constituent covers a large range.Cuzuel, V., Sizun, A., Cognon, G., Rivals, I., Heulard, F., Thiébaut, D., Vial, J., 2018. Human odor and forensics. Optimization of a comprehensive two-dimensional gas chromatography method based on orthogonality: How not to choose between criteria. Journal of Chromatography A 1536, 58-66. relationship between the phase ratio, β, of the primary (1D) and secondary (2D) separation dimensions of comprehensive two-dimensional (2D) gas chromatography (GC × GC) separations, and the implications of β on realization of maximal 2D peak capacity, nc,2D, are examined. A GC × GC chromatographic system with time-of-flight mass spectrometry, TOFMS, was otherwise held constant for the separation of a multi-component test mixture spanning a range of chemical functionalities, while only the β of the two analytical columns were changed, 1β for 1D and 2β for 2D. Six column sets were studied using common, commercially available β values. The β ratio, βR = 1β/2β, is defined as a quantitative metric to facilitate this study. It is demonstrated that βR plays a key role in maximizing nc,2D. Overall, βR substantially affected nc,2D by influencing retention factors on the 2D column, 2k, and thereby changing the modulation period, PM, necessary for proper 2D column separations. The necessary changes to PM modify the modulation ratio, MR, which affects the 1D column peak widths and 1nc due to the impact of undersampling. Through changes to 1β, the range of 2k can be controlled, with subsequent effects to both 2nc and 1nc. These effects were opposite in direction, such that improvements to 2nc may result in declines in 1nc. It is observed that due to the pseudo-isothermal nature of the 2D separation, there are diminishing returns to extending the 2nc at the cost of 1nc. In this particular study, column set 3 (1D: 20 m length, 250 μm i.d., 0.25 μm film; 2D: 2 m, 180 μm i.d., 0.2 μm film; βR = 1.11) with a PM of 3 s provided the highest theoretical nc,2D of ～8200, though this was at a relatively low MR of ～1.8. Column set 2 (1D: 20 m length, 250 μm i.d., 0.5 μm film; 2D: 2 m, 180 μm i.d., 0.2 μm film; βR = 0.56) with a PM of 1.5 s provided a high theoretical nc,2D of ～5800, at a much higher MR of ～3.7. Though column set 2 had a lesser total peak capacity than column set 3, its higher MR suggests that by improving the 1D column efficiency (i.e., narrowing the 1D column peak widths) to improve 1nc, can result in an increased theoretical nc,2D.Dachanuwattana, S., Jin, J., Zuloaga-Molero, P., Li, X., Xu, Y., Sepehrnoori, K., Yu, W., Miao, J., 2018. Application of proxy-based MCMC and EDFM to history match a Vaca Muerta shale oil well. Fuel 220, 490-502. complex discrete fractures in reservoir simulation is required to attain more realistic flow behavior of shale reservoirs. However, using local grid refinement to model discrete fractures is computationally expensive. Nevertheless, recent developments in a methodology called Embedded Discrete Fracture Model (EDFM) have overcome the computational complexity. In this study, we develop an efficient assisted history matching (AHM) workflow using proxy-based Markov chain Monte Carlo algorithm and integrating with the EDFM preprocessor. The workflow can automatically perform history matching, production forecasting and uncertainty quantification. It has been successfully applied on a shale oil well in Vaca Muerta formation.Dai, G., Ma, T., Zhu, S., Liu, Z., Chen, D., Bai, Y., Chen, L., He, J.-S., Zhu, J., Zhang, Y., Lü, X., Wang, X., Han, X., Feng, X., 2018. Large-scale distribution of molecular components in Chinese grassland soils: The influence of input and decomposition processes. Journal of Geophysical Research: Biogeosciences 123, 239-255. grasslands hold a third of the national soil organic carbon (OC) stocks but remain poorly investigated in terms of soil molecular components and their distribution patterns. Such information is important for understanding mechanisms governing grassland soil OC dynamics and its response to global changes. Here employing solvent-extractable compounds as a group of widely used biomarkers, we present a large-scale study on the distribution of different soil OC components (including plant- and microbial-derived carbohydrates and aliphatic and cyclic lipids) in the surface soils of Chinese grasslands, spanning from temperate grasslands in the arid/semiarid regions to alpine grasslands on the Qinghai-Tibetan Plateau. We show that alpine grassland soils are more enriched with carbohydrates and plant-derived compounds relative to the temperate counterparts due to temperature-inhibited decomposition. While plant belowground biomass plays a key role in explaining the spatial variation of compounds in the alpine grasslands, climatic variables do in the temperate region. In particular, aliphatic lipids accumulate with increasing mean annual temperature in the temperate grasslands due to a preferential decay of labile soil OC, whereas they decrease in the alpine grasslands owing to dilution by an enhanced plant input of nonlipid components. Collectively, these results demonstrate different mechanisms governing the distribution of solvent-extractable compounds in grassland soils, with climate-mediated decomposition processes dominating in the temperate grasslands and plant inputs being more important in the alpine region. In the context of climate change, alterations to soil OC input and decomposition processes may have varied impacts on soil carbon cycling in these two regions.Dai, X., Eduardo, G., 2018. Probing planets in extragalactic galaxies using quasar microlensing. The Astrophysical Journal Letters 853, Article L27., planets have been detected only in the Milky Way galaxy. Here, we show that quasar microlensing provides a means to probe extragalactic planets in the lens galaxy, by studying the microlensing properties of emission close to the event horizon of the supermassive black hole of the background quasar, using the current generation telescopes. We show that a population of unbound planets between stars with masses ranging from Moon to Jupiter masses is needed to explain the frequent Fe Kα line energy shifts observed in the gravitationally lensed quasar RXJ 1131–1231 at a lens redshift of z = 0.295 or 3.8 billion lt-yr away. We constrain the planet mass-fraction to be larger than 0.0001 of the halo mass, which is equivalent to 2000 objects ranging from Moon to Jupiter mass per main-sequence star.Dang, W., Zhang, J.-C., Tang, X., Wei, X.-L., Li, Z.-M., Wang, C.-H., Chen, Q., Liu, C., 2018. Investigation of gas content of organic-rich shale: A case study from Lower Permian shale in southern North China Basin, central China. Geoscience Frontiers 9, 559-575. gas content is an essential step in estimating the commerciality of gas reserves. In this study, eight shale core samples from the Mouye-1 well were measured using a homemade patented gas desorption apparatus to determine their gas contents. Due to the air contamination that is introduced into the desorption canister, a mathematical method was devised to correct the gas quantity and quality. Compared to the chemical compositions of desorbed gas, the chemical compositions of residual gas are somewhat different. In residual gas, carbon dioxide and nitrogen record a slight increase, and propane is first observed. This phenomenon may be related to the exposure time during the transportation of shale samples from the drilling site to the laboratory, as well as the differences in the mass, size and adsorptivity of different gas molecules. In addition to a series of conventional methods, including the USBM direct method and the Amoco Curve Fit (ACF) method, which were used here for lost gas content estimation, a Modified Curve Fit (MCF) method, based on the ‘bidisperse’ diffusion model, was established to estimate lost gas content. By fitting the ACF and MCF models to gas desorption data, we determined that the MCF method could reasonably describe the gas desorption data over the entire time period, whereas the ACF method failed. The failure of the ACF method to describe the gas desorption process may be related to its restrictive assumption of a single pore size within shale samples. In comparison to the indirect method, this study demonstrates that none of the three methods studied in this investigation (USBM, ACF and MCF) could individually estimate the lost gas contents of all shale samples and that the proportion of free gas relative to total gas has a significant effect on the estimation accuracy of the selected method. When the ratio of free gas to total gas is lower than 45%, the USBM method is the best for estimating the lost gas content, whereas when the ratio ranges from 45% to 75% or is more than 75%, the ACF and MCF methods, are the best options respectively.Daryasafar, N., Borazjani, O., Daryasafar, A., 2018. Adsorption of natural surfactants on sandstone rocks: Effect on the quality of the recovered asphaltenic oil. Petroleum Science and Technology 36, 525-530. surfactants are important for any enhancing oil recovery applications since these kinds of surfactants have less detrimental effects and also lower cost in comparison to the industrial surfactants. Adsorption of surfactants on sandstone minerals is an important issue which needs to be considered before applying any surfactant-based enhanced oil recovery technique. In this study, a new model based on adaptive neuro-fuzzy interference system was developed in order to simulate the kinetic behavior of natural surfactants adsorption on sandstone minerals with high accuracy. Performance of the model was investigated by comparing the results of the proposed model with the results of previous well-known kinetic models. Results demonstrated that this model has the highest accuracy compared to the other well-established models found in literature. Finally, in order to show the importance of modeling surfactants adsorption, the effect of a natural surfactant on the quality of the produced oil was investigated by performing SARA analysis on the recovered oil at various conditions of surfactant adsorption. It is shown that in the case of lower surfactant adsorption on sandstone minerals, the produced oil has higher asphaltene fractions.Daskalopoulou, K., Calabrese, S., Grassa, F., Kyriakopoulos, K., Parello, F., Tassi, F., D'Alessandro, W., 2018. Origin of methane and light hydrocarbons in natural fluid emissions: A key study from Greece. Chemical Geology 479, 286-301., a country characterised by intense seismic and volcanic activity, has a complex geodynamic and geological setting that favours the occurrence of many gas manifestations. In this study, we address the origin of CH4 and light hydrocarbons in cold and thermal emissions discharging along the Hellenic territory. Also, we investigate their possible relationship with the main geochemical composition of the gases and the different geological settings of the sampling sites. For this purpose we collected 101 new samples that were analysed for their chemical (O2, N2, CH4, CO2, He, Ne, Ar, H2, H2S and C2-C6 hydrocarbons) and isotopic (R/RA, δ13C-CO2, δ13C-CH4 and δ2H-CH4) composition. Results show that CH4 presents a wide range of concentrations (from <0.5 to 925,200?μmol/mol) and isotopic values (δ13C-CH4 from ?79.8 to +45.0‰ vs. V-PDB; δ2H-CH4 from ?311 to +301‰ vs. V-SMOW). Greece was subdivided in four geologic units (External [EH] and Internal [IH] Hellenides, Hellenic Hinterland [HH] and active Volcanic Arc [VA]) and a decreasing CH4 concentration from EH to HH was recognized, whereas CH4 showed intermediate concentrations in VA. The CH4/(C2H6?+?C3H8) ratios (from 1.5 to 93,200), coupled with CH4 isotopic features, suggest that the light alkanes derive from different primary sources and are affected by secondary processes. An almost exclusive biotic, mainly microbial, origin of CH4 can be attributed to EH gases. Cold gases at IH have mainly a thermogenic origin, although some gases connected to continental serpentinization may have an abiogenic origin. Methane in gases bubbling in thermal waters of IH, HH and VA and fumarolic gases of the VA seem to have an abiogenic origin, although their chemical and isotopic characteristics may have been produced by secondary oxidation of thermogenic CH4, a process that in some of the sampled gases causes extremely positive isotopic values (δ13C-CH4 up to +45.0‰ vs. V-PDB and δ2H-CH4 up to +301‰ vs. V-SMOW).Date, Y., Kikuchi, J., 2018. Application of a deep neural network to metabolomics studies and its performance in determining important variables. Analytical Chemistry 90, 1805-1810. neural networks (DNNs), which are kinds of the machine learning approaches, are powerful tools for analyzing big sets of data derived from biological and environmental systems. However, DNNs are not applicable to metabolomics studies because they have difficulty in identifying contribution factors, e.g., biomarkers, in constructed classification and regression models. In this paper, we describe an improved DNN-based analytical approach that incorporates an importance estimation for each variable using a mean decrease accuracy (MDA) calculation, which is based on a permutation algorithm; this approach is called DNN-MDA. The performance of the DNN-MDA approach was evaluated using a data set of metabolic profiles derived from yellowfin goby that lived in various rivers throughout Japan. Its performance was compared with that of conventional multivariate and machine learning methods, and the DNN-MDA approach was found to have the best classification accuracy (97.8%) among the examined methods. In addition to this, the DNN-MDA approach facilitated the identification of important variables such as trimethylamine N-oxide, inosinic acid, and glycine, which were characteristic metabolites that contributed to the discrimination of the geographical differences between fish caught in the Kanto region and those caught in other regions. As a result, the DNN-MDA approach is a useful and powerful tool for determining the geographical origins of specimens and identifying their biomarkers in metabolomics studies that are conducted in biological and environmental systems.Davis, J.M., Stoll, D.R., 2018. Likelihood of total resolution in selective comprehensive two-dimensional liquid chromatography with parallel processing: Simulation and theory. Journal of Chromatography A 1537, 43-57. probability that all peaks are separated by a resolution of 1.5 or more in selective comprehensive two-dimensional liquid chromatography (sLC?×?LC) is computed for simple model systems of 5 to 60 peaks and first-dimension (1D) gradient times of 100 to 2000?s. The computations include mimics of a commercial instrument, whose fixed second-dimension (2D) gradient time and use of one cycle time for initialization reduces relative to an earlier report. For serial sLC?×?LC, in which a single device collects and transfers 1D multiplets to the second dimension, under practical conditions is predicted to be only slightly larger than the probability of total resolution in LC?×?LC for separations of the same duration in each case. To increase , two model systems are proposed based on parallel processing, in which one device collects multiplets from the first separation while a second device simultaneously transfers fractions from previously collected multiplets to the second dimension for further separation. A sum of probabilities guideline is proposed by which optimal fixed 2D gradient times, ranging from 9.5 to 12?s, are found for both serial and parallel models. The increases of based on parallel processing are modest; the largest is only 0.062 for one system and 0.106 for the other, relative to the serial model. A theory is derived that rationalizes the modesty of the increase, which was unexpected. It shows that equals the probability of total resolution in the first dimension, plus the product of the probability that all 1D multiplets are transferred to the second dimension and the probability that all multiplets are separated in the second dimension. The theory shows that, although parallel processing is better than serial processing for multiplet transfer, the ability to leverage this gain is offset by the limited probability that all multiplets are then actually separated in the second dimension, which is only about 0.55 for conditions where the change from serial to parallel processing is most beneficial. With these findings in hand, two scenarios are examined for future consideration: one in which the 2D peak capacity is doubled, and another in which multiplets are always transferred to the second dimension. The latter shows considerable promise for increasing substantially beyond its counterpart in LC?×?LC. For example, a 50% probability of separating all peaks in a 15-component mixture can be reached in 1150?s using LC?×?LC. The same probability can be reached in the same time for a sample with nearly twice as many components (27) in the case of sLC?×?LC, assuming transfer of all multiplets to the second dimension. These findings will be useful to those considering systematic approaches to developing 2D-LC methods for moderately complex mixtures, and to those interested in instrument development for 2D-LC.Davison, I., Steel, I., 2018. Geology and hydrocarbon potential of the East African continental margin: a review. Petroleum Geoscience 24, 57-91. East African margin has a complex structure due to multiple phases of rifting with different stretching directions. The main phase of rifting leading to Indian Ocean opening lasted from the Late Pliensbachian to the Bajocian (c. 183?–?170?Ma). This occurred during impingement of the Bouvet hotspot which weakened the lithosphere sufficiently to allow continental break-up. Thick salt and marine shales were deposited during the Toarcian in the Majunga, Ambilobe and Mandawa basins and the onshore Ogaden Basin; marking the onset of the Indian Ocean marine incursion, when good quality oil-prone source rocks were deposited at this time. The recent giant gas discoveries in Tanzania and Mozambique are believed to be sourced from overmature Jurassic or, possibly, deeper Permian age Karoo shales. The margin from the Lamu Basin in the north to the Zambesi Delta in the south is covered by thick Tertiary and Cretaceous sediment derived from the East African rift shoulders, and Lower Jurassic source rocks are predicted to be in the gas window along most of the margin. However, the margins in South Africa, south Mozambique, northern Somalia and Madagascar are less deeply buried, and have better oil potential.The large Tsimimo and Bemolanga tar sand deposits and the recent announcement of an oil rim in the Inhasorro Field indicate that there are good oil-prone source rocks in the Karoo rifts and in the Albian Domo shales; and the search for oil continues with companies exploring in areas where Jurassic source rocks may be less deeply buried, and/or potential Albian–Turonian-aged source rocks are sufficiently buried to generate oil.Davtian, N., Bard, E., Ménot, G., Fagault, Y., 2018. The importance of mass accuracy in selected ion monitoring analysis of branched and isoprenoid tetraethers. Organic Geochemistry 118, 58-62. the new proxies based on the distribution of glycerol dialkyl glycerol tetraethers (GDGTs), the BIT index (Branched and Isoprenoid Tetraether index) is one of the most difficult to determine accurately, as shown by two round-robin GDGT studies. Sensitivity to mass spectrometer settings and tuning, and a diversity of mass spectrometry techniques may explain the relatively large observed interlaboratory scatter. However, the mass defect difference between crenarchaeol and branched GDGTs (brGDGTs) has never been specifically scrutinized. In this study, we analyzed five sediment samples with contrasting BIT values using about 60?m/z values to assess the shape of GDGT peaks using selected ion monitoring. We then assessed the biases in relative GDGT signals and mass spectrometry-derived BIT values under two scenarios which ignore the systematic mass defect difference between crenarchaeol and brGDGTs. Our results show that approximate mass selection for GDGT analysis using selected ion monitoring generates losses of relative GDGT signals of up to 36%. The observed effects on BIT values are maximal for intermediate BIT values, with shifts of BIT values of ±0.1 unit. The shifts of BIT values due to approximate mass selection are thus not negligible compared to the interlaboratory scatter evidenced by the latest round-robin GDGT study.Davudov, D., Moghanloo, R.G., 2018. Impact of pore compressibility and connectivity loss on shale permeability. International Journal of Coal Geology 187, 98-113. present a novel approach to describe how micro-fracture closure, pore volume compressibility, and connectivity loss change intrinsic permeability of shale formations as a function of effective stress. Shale resources illustrate distinct characteristics, such as micro-scale pores (IUPAC definition), ultra-low permeability, and complex pore network system. Moreover, experimental results indicate that permeability reduction owing to increased effective stress in shale samples might be as large as two orders of magnitude. This significant reduction is often explained by micro-fracture closure while impact of pore connectivity loss is often neglected. Thus, we propose a novel model through which permeability reduction is described owing to combination of three main mechanisms: (1) micro crack closure (2) pore shrinkage and (3) connectivity loss due to bond breakage between interconnected pores.We use fractal and percolation theories and formulate a permeability model as a function of pore throat radius, porosity, pore size distribution, and average coordination number (average number of available/connected neighbor pores). The proposed model is validated using experimental data for 10 sandstone samples. Additionally, for selected shale samples, results of proposed model are compared with Katz-Thompson and Swanson methods. Furthermore, experimental data for two sandstone and two shale samples are utilized to evaluate connectivity reduction with effective stress. Using Walsh model, first we identified and isolated crack/fracture-dominated permeability region for shale samples and studied impact of pore shrinkage and connectivity loss as a function of effective stress for the remainder of the datasets.Results indicate that permeability values obtained from proposed model are consistent with experimental data for sandstone samples as well as predictions obtained from Katz-Thompson and Swanson methods for shale samples. Moreover, when effects of both pore shrinkage and connectivity loss are simultaneously analyzed, the results proved that connectivity loss (as expected) is insignificant in sandstone samples and that permeability reduction can be explained only by pore volume compressibility effects. However, in shale formations, impact of bond breakage and connectivity loss on permeability reduction is dominant. The results suggest that average coordination number can decrease as lower as 50% of the original value when effective stress exceeds 17,000 psi.The result of this study suggests that in shale formations permeability reduction should be corrected to account for micro-crack closure at early stage and for both pore compressibility and connectivity loss at late stage of production. This may well change the industry's predictions of the reservoir performance in unconventional shale plays.de Oliveira Livera, D., Leshuk, T., Peru, K.M., Headley, J.V., Gu, F., 2018. Structure-reactivity relationship of naphthenic acids in the photocatalytic degradation process. Chemosphere 200, 180-190. extraction in Canada's oil sands generates oil sands process-affected water (OSPW) as a toxic by-product. Naphthenic acids (NAs) contribute to the water's toxicity, and treatment methods may need to be implemented to enable safe discharge. Heterogeneous photocatalysis is a promising advanced oxidation process (AOP) for OSPW remediation, however, its successful implementation requires understanding of the complicated relationship between structure and reactivity of NAs. This work aimed to study the effect of various structural properties of model compounds on the photocatalytic degradation kinetics via high resolution mass spectrometry (HRMS), including diamondoid structures, heteroatomic species, and degree of unsaturation. The rate of photocatalytic treatment increased significantly with greater structural complexity, namely with carbon number, aromaticity and degree of cyclicity, properties that render particular NAs recalcitrant to biodegradation. It is hypothesized that a superoxide radical-mediated pathway explains these observations and offers additional benefits over traditional hydroxyl radical-based AOPs. Detailed structure-reactivity investigations of NAs in photocatalysis have not previously been undertaken, and the results described herein illustrate the potential benefit of combining photocatalysis and biodegradation as a complete OSPW remediation technology.Deeba, F., Pruthi, V., Negi, Y.S., 2018. Aromatic hydrocarbon biodegradation activates neutral lipid biosynthesis in oleaginous yeast. Bioresource Technology 255, 273-280. this study, the biodegradation ability of oleaginous yeast Cryptococcus psychrotolerans IITRFD for aromatic hydrocarbons (AHs) was investigated. It was found to completely degrade range of AHs such as 1?g/L phenol, 0.75?g/L naphthalene, 0.50?g/L anthracene and 0.50?g/L pyrene with lipid productivity (g/L/h) of 0.0444, 0.0441, 0.0394 and 0.0383, respectively. This work demonstrated the ring cleavage pathways of AHs by this yeast which follow ortho route for phenol and naphthalene while meta route for anthracene and pyrene degradation. The end products generated during biodegradation of AHs are feed as precursors for de novo triacylglycerols (TAG) biosynthesis pathway of oleaginous yeast. A high quantity of lipid content (46.54%) was observed on phenol as compared to lipid content on naphthalene (46.38%), anthracene (44.97%) and pyrene (44.16%). The lipid profile revealed by GC–MS analysis shows elevated monounsaturated fatty acid (MUFA) content with improved biodiesel quality.Dement’ev, V.A., 2018. Origin of the simplest genetic code as an evolutionary stage of the Earth. Geochemistry International 56, 65-70. minimal set of conditions is found under which a primitive genetic code can be formed in the chemical world in which polypeptides and polynucleotides can be produced. Molecular modeling demonstrates that multiple cycles of synthesis and thermal destruction of biopolymers result in spontaneous complication of their structure. This evolutionary progressive complication of polypeptides and polynucleotides coding them results in certain specific functions of the polypeptides, which are similar to properties of enzymes. Computer simulations confirm the internal logical consistency of the simplified scenario suggested for the origin of a genetic code as a process of transferring information on the structure of biomolecules to the historical future, in spite of the continuous thermal decomposition of these structures. Original Russian Text ? V.A. Dement’ev, 2018, published in Geokhimiya, 2018, No. 1, pp. 70–76.Derguine-Mecheri, L., Kebbouche-Gana, S., Khemili-Talbi, S., Djenane, D., 2018. Screening and biosurfactant/bioemulsifier production from a high-salt-tolerant halophilic Cryptococcus strain YLF isolated from crude oil. Journal of Petroleum Science and Engineering 162, 712-724. yeasts were isolated from different biotopes including food samples, waste and sand samples collected from areas contaminated with hydrocarbons in Algeria. Isolates were screened for biosurfactant/bioemulsifier production in mineral salt medium and in high salinity using emulsification index (E24), drop-collapse test, spread oil technique and hemolytic activity. Fifty of one hundred isolates were positive for almost all the qualitative tests, four of them were the best strains for biosurfactants production with emulsions over than 60%. More interestingly, one high-salt-tolerant yeast isolate was the most potent biosurfactants producing yeast with an emulsification index of 69.50 ± 0.70. It was identified by morphological, physiological and biochemical tests and by 5.8s-rDNA Analysis as Cryptococcus sp.YLF. This strain produced biosurfactant using different carbon and nitrogen sources and when grown in low-cost fermentative media based on agro industrial by-products and wastes like whey, molasses, corn steep liquor, date syrup and olive mill wastewater (OMW) supplemented with NaCl (2.5 M). The biosurfactant produced by Cryptococcus sp. YLF was partially characterized as glycolipid based on the estimation of macromolecules, TLC and IR analysis. The crude biosurfactant demonstrated stability regarding surface tension reduction and emulsification activity in a range of temperatures (5–100 °C), pH (2–12) and high salinities (1–10%). The partially purified biosurfactant showed promising potential for application in enhanced oil recovery (EOR).Desfontaine, V., Capetti, F., Nicoli, R., Kuuranne, T., Veuthey, J.-L., Guillarme, D., 2018. Systematic evaluation of matrix effects in supercritical fluid chromatography versus liquid chromatography coupled to mass spectrometry for biological samples. Journal of Chromatography B 1079, 51-61. effects (ME) is acknowledged as being one of the major drawbacks of quantitative bioanalytical methods, involving the use of liquid chromatography coupled to mass spectrometry (LC-MS). In the present study, the incidence of ME in SFC-MS/MS and LC-MS/MS in the positive mode electrospray ionization (ESI+) was systematically compared for the analysis of urine and plasma samples using two representative sets of 40 doping agents and 38 pharmaceutical compounds, respectively. Three different SFC stationary phase chemistries were employed, to highlight the importance of the column in terms of selectivity. Biological samples were prepared using two different sample treatments, including a non-selective sample clean-up procedure (dilute and shoot (DS) and protein precipitation (PP) for urine and plasma samples, respectively) and a selective sample preparation, namely solid phase extraction (SPE) for both matrices.The lower susceptibility to ME in SFC vs. reversed phase LC (RPLC) was verified in all the experiments performed on urine, and especially when a simple DS procedure was applied. Also, with the latter, the performance strongly varied according to the selected SFC stationary phase, whereas the results were quite similar with the three SFC columns, in the case of SPE clean-up. The same trend was observed with plasma samples. Indeed, with the PP procedure, the occurrence of ME was different on the three SFC columns, and only the 2-picolylamine stationary phase chemistry displayed lower incidence of ME compared to LC-MS/MS. On the contrary, when a SPE clean-up was carried out, the results were similar to the urine samples, with higher performance of SFC vs. LC and limited discrepancies between the three SFC columns. The type of ME observed in LC-MS/MS was generally a signal enhancement and an ion suppression for urine and plasma samples, respectively. In the case of SFC-MS/MS, the type of ME randomly varied according to the analyzed matrix, selected column and sample treatment.Deviese, T., Comeskey, D., McCullagh, J., Bronk Ramsey, C., Higham, T., 2018. New protocol for compound-specific radiocarbon analysis of archaeological bones. Rapid Communications in Mass Spectrometry 32, 373-379.: For radiocarbon results to be accurate, samples must be free of contaminating carbon. Sample pre-treatment using a high-performance liquid chromatography (HPLC) approach has been developed at the Oxford Radiocarbon Accelerator Unit (ORAU) as an alternative to conventional methods for dating heavily contaminated bones. This approach isolates hydroxyproline from bone collagen, enabling a purified bone-specific fraction to then be radiocarbon dated by accelerator mass spectrometry (AMS). Methods: Using semi-preparative chromatography and non-carbon-based eluents, this technique enables the separation of underivatised amino acids liberated by hydrolysis of extracted bone collagen. A particular focus has been the isolation of hydroxyproline for single-compound AMS dating since this amino acid is one of the main contributors to the total amount of carbon in mammalian collagen. Our previous approach, involving a carbon-free aqueous mobile phase, required a two-step separation using two different chromatographic columns. Results: This paper reports significant improvements that have been recently made to the method to enable faster semi-preparative separation of hydroxyproline from bone collagen, making the method more suitable for routine radiocarbon dating of contaminated and/or poorly preserved bone samples by AMS. All steps of the procedure, from the collagen extraction to the correction of the AMS data, are described. Conclusions: The modifications to the hardware and to the method itself have reduced significantly the time required for the preparation of each sample. This makes it easier for other radiocarbon facilities to implement and use this approach as a routine method for preparing contaminated bone samples.Devièse, T., Van Ham-Meert, A., Hare, V.J., Lundy, J., Hommel, P., Ivanovich Bazaliiskii, V., Orton, J., 2018. Supercritical fluids for higher extraction yields of lipids from archeological ceramics. Analytical Chemistry 90, 2420-2424. extraction and study of organic residues from ceramics has been a subject of interest for the last 50 years in archeology and archeological science. Lipids are among the best-preserved organic substances in archeological contexts and can provide information about the diets of ancient populations as well as past environments. Here, we present a method which demonstrates significantly improved extraction of lipids from archeological pots by replacing liquid organic solvents with supercritical fluids. Optimization of the procedure using response surface methodology (RSM) approach showed that, on our system, optimal conditions for supercritical extraction of lipids from synthetic fired clay ceramics could be achieved using carbon dioxide with 16 vol % of cosolvent EtOH–H2O (95:5 v/v) in 90 min at a flow rate of 2.3 mL/min, for a pressure of 30 MPa and a temperature of 50 °C. For all reference and archeological samples included in this study, lipid yields obtained by supercritical fluid extraction under these optimal conditions were systematically higher than by conventional solvent extraction. This study also highlighted a variability of the ratio of unsaturated versus saturated fatty acids depending on the extraction method. This can have important implications in the identification of the residue(s). The increased extraction efficiency provided by supercritical fluids, as well as their minimally destructive nature, enable new and refined approaches to residue analysis and dating of archeological ceramics.Dhami, N.K., Mukherjee, A., Watkin, E.L.J., 2018. Microbial diversity and mineralogical-mechanical properties of calcitic cave speleothems in natural and in vitro biomineralization conditions. Frontiers in Microbiology 9, 40. doi: 10.3389/fmicb.2018.00040. mineral formations are a window into important processes leading to carbon storage and mineralized carbonate structures formed through abiotic and biotic processes. In the current study, we made an attempt to undertake a comprehensive approach to characterize the mineralogical, mechanical, and microbial properties of different kinds of speleothems from karstic caves; with an aim to understand the bio-geo-chemical processes in speleothem structures and their impact on nanomechanical properties. We also investigated the biomineralization abilities of speleothem surface associated microbial communities in vitro. Mineralogical profiling using techniques such as X-ray powder Diffraction (XRD) and Tescan Integrated Mineral Analyzer (TIMA) demonstrated that calcite was the dominant mineral in the majority of speleothems with Energy Dispersive X-ray Analysis (EDS) indicating a few variations in the elemental components. Differing proportions of polymorphs of calcium carbonate such as aragonite and vaterite were also recorded. Significant variations in trace metal content were recorded through Inductively Coupled Plasma Mass Spectrometer (ICP-MS). Scanning Electron Microscopy (SEM) analysis revealed differences in morphological features of the crystals which varied from triangular prismatic shapes to etched spiky forms. Microbial imprints and associations were seen in a few sections. Analysis of the associated microbial diversity showed significant differences between various speleothems at Phylum level; although Proteobacteria and Actinobacteria were found to be the predominant groups. Genus level microbial associations showed a relationship with the geochemistry, mineralogical composition, and metal content of the speleothems. The assessment of nanomechanical properties measured by Nanoindentation revealed that the speleothems with a dominance of calcite were stronger than the speleothems with mixed calcium carbonate polymorphs and silica content. The in vitro metabolic activity of the microbial communities associated with the surfaces of the speleothems resulted in calcium carbonate crystal precipitation. Firmicutes and Proteobacteria dominated these populations, in contrast to the populations seen in natural systems. The precipitation of calcium carbonate crystals in vitro indicated that microbial metabolic activity may also play an important role in the synthesis and dissociation of biominerals in the natural environment. Our study provides novel evidence of the close relationship between mineralogy, microbial ecology, geochemistry, and nanomechanical properties of natural formations.Di Donato, P., Romano, I., Mastascusa, V., Poli, A., Orlando, P., Pugliese, M., Nicolaus, B., 2018. Survival and adaptation of the thermophilic species Geobacillus thermantarcticus in simulated spatial conditions. Origins of Life and Evolution of Biospheres 48, 141-158. studies the origin and evolution of life on Earth and in the universe. According to the panspermia theory, life on Earth could have emerged from bacterial species transported by meteorites, that were able to adapt and proliferate on our planet. Therefore, the study of extremophiles, i.e. bacterial species able to live in extreme terrestrial environments, can be relevant to Astrobiology studies. In this work we described the ability of the thermophilic species Geobacillus thermantarcticus to survive after exposition to simulated spatial conditions including temperature’s variation, desiccation, X-rays and UVC irradiation. The response to the exposition to the space conditions was assessed at a molecular level by studying the changes in the morphology, the lipid and protein patterns, the nucleic acids. G. thermantarcticus survived to the exposition to all the stressing conditions examined, since it was able to restart cellular growth in comparable levels to control experiments carried out in the optimal growth conditions. Survival was elicited by changing proteins and lipids distribution, and by protecting the DNA’s integrity.Dial, R.J., Ganey, G.Q., Skiles, S.M., 2018. What color should glacier algae be? An ecological role for red carbon in the cryosphere. FEMS Microbiology Ecology 94, Article fiy007. secondary pigments in glacier algae play an adaptive role in melting snow and ice. We advance this hypothesis using a model of color-based absorption of irradiance, an experiment with colored particles in snow, and the natural history of glacier algae. Carotenoids and phenols—astaxanthin in snow-algae and purpurogallin in ice-algae—shield photosynthetic apparatus by absorbing overabundant visible wavelengths, then dissipating the excess radiant energy as heat. This heat melts proximal ice crystals, providing liquid-water in a 0°C environment and freeing up nutrients bound in frozen water. We show that purple-colored particles transfer 87%–89% of solar energy absorbed by black particles. However, red-colored particles transfer nearly as much (85%–87%) by absorbing peak solar wavelengths and reflecting the visible wavelengths most absorbed by nearby ice and snow crystals; this latter process may reduce potential cellular overheating when snow insulates cells. Blue and green particles transfer only 80%–82% of black particle absorption. In the experiment, red-colored particles melted 87% as much snow as black particles, while blue particles melted 77%. Green-colored snow-algae naturally occupy saturated snow where water is non-limiting; red-colored snow-algae occupy drier, water-limited snow. In addition to increasing melt, we suggest that esterified astaxanthin in snow-alga cells increases hydrophobicity to remain surficial.Dijkstra, N., Hagens, M., Egger, M., Slomp, C.P., 2018. Post-depositional formation of vivianite-type minerals alters sediment phosphorus records. Biogeosciences 15, 861-883. (P) concentrations in sediments are frequently used to reconstruct past environmental conditions in freshwater and marine systems, with high values thought to be indicative of a high biological productivity. Recent studies suggest that the post-depositional formation of vivianite, an iron(II)-phosphate mineral, might significantly alter trends in P with sediment depth. To assess its importance, we investigate a sediment record from the Bornholm Basin that was retrieved during the Integrated Ocean Drilling Program (IODP) Baltic Sea Paleoenvironment Expedition 347 in 2013, consisting of lake sediments overlain by brackish–marine deposits. Combining bulk sediment geochemistry with microanalysis using scanning electron microscope energy dispersive spectroscopy (SEM-EDS) and synchrotron-based X-ray absorption spectroscopy (XAS), we demonstrate that vivianite-type minerals rich in manganese and magnesium are present in the lake deposits just below the transition to the brackish–marine sediments (at 11.5 to 12?m sediment depth). In this depth interval, phosphate that diffuses down from the organic-rich, brackish–marine sediments meets porewaters rich in dissolved iron in the lake sediments, resulting in the precipitation of iron(II) phosphate. Results from a reactive transport model suggest that the peak in iron(II) phosphate originally occurred at the lake–marine transition (9 to 10?m) and moved downwards due to changes in the depth of a sulfidization front. However, its current position relative to the lake–marine transition is stable as the vivianite-type minerals and active sulfidization fronts have been spatially separated over time. Experiments in which vivianite was subjected to sulfidic conditions demonstrate that incorporation of manganese or magnesium in vivianite does not affect its susceptibility to sulfide-induced dissolution. Our work highlights that post-depositional formation of iron(II) phosphates such as vivianite has the potential to strongly alter sedimentary P records particularly in systems that are subject to environmental perturbation, such as a change in primary productivity, which can be associated with a lake–marine transition.Dill, H.G., Kaufhold, S., 2018. The Totumo mud volcano and its near-shore marine sedimentological setting (North Colombia) — From sedimentary volcanism to epithermal mineralization. Sedimentary Geology 366, 14-31. Holocene mud volcano exposed at Totumo (younger than 4150?±?50?yr BP) lines up together with some other landforms of its kind along the Caribbean Coast in northern Colombia. It currently vents a mud of the silicate-phosphate-bearing sulfur-sodium chloride type. The mud volcanoes evolved in an active continental margin setting of the South American Cordillera with high seismicity and affected by pervasive neotectonic structural disturbances. During the Neogene and Quaternary linear terrigenous shoreline sediments alternating with delta deposits evolved on this mobile crustal segment between the Andes and ancient Precambrian cratons. Meso- to microtidal sedimentary settings during transgression and progradation created meta- to instable sedimentary and petrophysical conditions (e.g. overpressure and gas-bearing bubble sands), favorable for the formation of mud volcanoes, whose lithofacies is subdivided into (1) footwall facies (detritus from metabasic, -pelitic source rocks), (2) mud volcano plus lateral facies (material from deep-seated hydrothermal sources, hydrocarbon plays, and brine reflux from the sea), (3) hanging wall facies, sand characterized by a strong longshore drift. The sedimentary volcanism in the area is characterized by different temperatures of formation: (1) pre-stage (&lt;100?°C) and (2) recent stage (≈25?°C). Heavy (pyroxene, amphibole, epidote-clinozoisite, Fe-Ti silicates and oxides, garnet, alumosilicates, tourmaline, zircon, barite, Fe sulfides and -sulfates), light (Ca sulfates, calcite, quartz, feldspar) and clay minerals (kaolinite, mica, pyrophyllite, chlorite, vermiculite) are efficient tools to determine the source of mud, to subdivide the mud volcano system as to its facies and describe its physical-chemical regime as to the temperature of formation, pH and Eh values. The mud volcano system of Totumo bridges the gap between sedimentary “volcanism” and epithermal hot spring deposits of intermediate to high sulfidation and forms a useful “guide” to hydrocarbon accumulation.Doan, T.N., Fujihara, A., 2018. Enantiomer-selective photo-induced reaction of protonated tryptophan with disaccharides in the gas phase. Origins of Life and Evolution of Biospheres 48, 123-130. order to investigate chemical evolution in interstellar molecular clouds, enantiomer-selective photo-induced chemical reactions between an amino acid and disaccharides in the gas phase were examined using a tandem mass spectrometer containing an electrospray ionization source and a cold ion trap. Ultraviolet photodissociation mass spectra of cold gas-phase noncovalent complexes of protonated tryptophan (Trp) enantiomers with disaccharides consisting of two D-glucose units, such as D-maltose or D-cellobiose, were obtained by photoexcitation of the indole ring of Trp. NH2CHCOOH loss via cleavage of the Cα–Cβ bond in Trp induced by hydrogen atom transfer from the NH3 + group of a protonated Trp was observed in a noncovalent heterochiral H+(l-Trp)(D-maltose) complex. In contrast, a photo-induced chemical reaction forming the product ion with m/z 282 occurs in homochiral H+(d-Trp)(D-maltose). For D-cellobiose, both NH2CHCOOH elimination and the m/z 282 product ion were observed, and no enantiomer-selective phenomena occurred. The m/z 282 product ion indicates that the photo-induced C-glycosylation, which links D-glucose residues to the indole moiety of Trp via a C–C bond, can occur in cold gas-phase noncovalent complexes, and its enantiomer-selectivity depends on the structure of the disaccharide.Donoghue, P., 2018. Evolution: Divining the nature of the ancestral vertebrate. Current Biology 27, R277-R279. of the ancestral vertebrate are increasingly complex because the previously understudied cyclostomes have been revealed as simplified and specialised. New research uncovers another ancestral vertebrate character, resolving a century of debate over whether the ancestral vertebrate bore gills.Du, E., Zhao, Q., Xiao, Y., Cai, L., Tao, R., 2018. Electric field suppressed turbulence and reduced viscosity of asphaltene base crude oil sample. Fuel 220, 358-362. through pipes, such as crude oil through pipelines, are the most common and important method of transportation of fluids. To enhance the flow output through the pipeline requires reducing viscosity and suppressing turbulence simultaneously and effectively. Unfortunately, no method is currently available to accomplish both goals simultaneously. Here we show that electrorheology provides a solution which was confirmed by NIST SANS, DOE and Daqing oil field pipeline testing. When a strong electric field is applied along the flow direction in a small section of the pipeline, the field polarizes and aggregates the particles suspended in the base liquid into short chains along the flow direction. Such aggregation breaks the rotational symmetry and makes the fluid viscosity anisotropic. In the directions perpendicular to the flow, the viscosity is substantially increased, effectively suppressing the turbulence. Along the flow direction, the viscosity is significantly reduced; thus the flow along the pipeline is enhanced. Our laboratory experiments with Cenovus crude oil through a pipeline verified the theoretical predictions which were confirmed by field tests. The technology consumes very little energy and will be very useful for both offshore and onshore crude oil production and transportation about Cenovus asphaltene base crude oil sample.Du, Y., Sang, S., Wang, W., Liu, S., Wang, T., Fang, H., 2018. Experimental study of the reactions of supercritical CO2 and minerals in high-rank coal under formation conditions. Energy & Fuels 32, 1115-1125. study investigates the influence of supercritical CO2 (scCO2) injection on minerals in high-rank coal under the temperature, pressure, and hydrologic conditions of a deep coalbed. A typical high-rank coal reservoir in the Qinshui basin, the #3 coal seam, is the focus of this research. A coal–scCO2 geochemical reaction experiment is conducted to simulate the 2000 m burial depth of the coal seam. Field emission scanning electron microscopy is used to determine the locations of specific minerals and observe the effects of scCO2–H2O on these minerals at the micrometer scale. These results are combined with X-ray diffraction and inductively coupled plasma-atomic emission spectrometry and mass spectrometry analysis results, and the effects of the scCO2–H2O fluid on minerals in the high-rank coal over a short period are discussed. In addition, the influence on coal reservoir structure was studied based on intrusive mercury and liquid nitrogen adsorption experiment. The results suggest that instantaneous CO2 injection can provide a large amount of H+, and the initial ion release rate is high. Because of differences in mineral dissolution rates, scCO2–H2O has the strongest effect on calcite, followed by dolomite, aluminum hydroxide minerals, chlorite, and albite; however, effects are not obvious for illite, kaolinite, and quartz. Because of the low mineral content of the coal and the short experimental period, independent secondary carbon sequestration minerals did not form. However, the surface of aluminum hydroxide minerals reached partial dissolution equilibrium, and new layered aluminum silicate minerals were generated. The dissolution of carbonate minerals, albite, and chlorite increased the pore volume of the coal reservoir and improved the permeability of the samples. New layered aluminum silicate minerals and the chlorite with new occurrence increased the surface areas of samples after the reactions. After the reaction, porosity, pore volume, and surface area of the sample were greater, which also confirmed the positive transformation effect of the mineral changes on the reservoir.Duncan, K.D., Lanekoff, I., 2018. Oversampling to improve spatial resolution for liquid extraction mass spectrometry imaging. Analytical Chemistry 90, 2451-2455. extraction mass spectrometry imaging (MSI) experiments provide users with direct analysis of biological surfaces with minimal sample preparation. Until now, much of the effort to increase spatial resolution for MSI with liquid extraction techniques has focused on reducing the size of the sampling area. However, this can be experimentally challenging. Here, we present oversampling as a simple alternative to increase the spatial resolution using nanospray desorption electrospray ionization (nano-DESI) MSI. By imaging partial rat spinal cord tissue sections, two major concerns with oversampling are addressed: whether endogenous molecules are significantly depleted from repeated sampling events and whether analytes are redistributed as a result of oversampling. In depth examination of ion images for representative analytes show that depletion and redistribution do not affect analyte localization in the tissue sample. Nano-DESI MSI experiments using three times oversampling provided higher spatial resolution, allowing the observation of features not visible with undersampling. Although proper care must be taken to ensure that oversampling will work in specific applications, we envision oversampling as a simple approach to increase image quality for liquid extraction MSI techniques.Duranton, C., Bedossa, T., Gaunet, F., 2018. Pet dogs synchronize their walking pace with that of their owners in open outdoor areas. Animal Cognition 21, 219-226. between interacting partners is associated with a high level of behavioural synchronization in many species. Pet dogs are known to share strong affiliative bonds with their owners and to synchronize their behaviour with them when moving freely indoors. Surprisingly, outdoor dog–human interspecific synchronization has seldom been investigated. We therefore explored whether, when allowed to move freely in a familiar outdoor space, dogs synchronize their behaviour with their owners’ movements. We found that dogs visibly synchronized both their location (staying in close proximity) and their activity (moving when their owner moved, and at the same pace, and standing still when their owner stood still) with those of their owners. By demonstrating that owners act as attractors for their dogs in an outdoor space, the present study contributes new data to the understanding of interspecific behavioural synchronization.Dyksma, S., Pjevac, P., Ovanesov, K., Mussmann, M., 2018. Evidence for H2 consumption by uncultured Desulfobacterales in coastal sediments. Environmental Microbiology 20, 450-461. hydrogen (H2) is the key intermediate in the anaerobic degradation of organic matter. Its removal by H2-oxidizing microorganisms is essential to keep anaerobic degradation energetically favourable. Sulfate-reducing microorganisms (SRM) are known as the main H2 scavengers in anoxic marine sediments. Although the community of marine SRM has been extensively studied, those consuming H2 in situ are completely unknown. We combined metagenomics, PCR-based clone libraries, single-amplified genomes (SAGs) and metatranscriptomics to identify potentially H2-consuming SRM in anoxic coastal sediments. The vast majority of SRM-related H2ase sequences were assigned to group 1b and 1c [NiFe]-H2ases of the deltaproteobacterial order Desulfobacterales. Surprisingly, the same sequence types were similarly highly expressed in spring and summer, suggesting that these are stable and integral members of the H2-consuming community. Notably, one sequence cluster from the SRM group 1 consistently accounted for around half of all [NiFe]-H2ase transcripts. Using SAGs, we could link this cluster with the 16S rRNA genes of the uncultured Sva0081-group of the family Desulfobacteraceae. Sequencing of 16S rRNA gene amplicons and H2ase gene libraries suggested consistently high in situ abundance of the Sva0081 group also in other marine sediments. Together with other Desulfobacterales these likely are important H2-scavengers in marine sediments.Edress, N.A.A., Oplu?til, S., S?korová, I., 2018. Depositional environments of the Jurassic Maghara main coal seam in north central Sinai, Egypt. Journal of African Earth Sciences 140, 241-255. channel samples with a cumulative thickness of about 4?m collected from three sections of the Maghara main coal seam in the middle Jurassic Safa Formation have been studied for their lithotype and maceral compositions to reconstruct the character of peat swamp, its hydrological regime and the predominating type of vegetation. Lithotype composition is a combination of dully lithotypes with duroclarain (19% of total cumulative thickness), clarodurain (15%), black durain (15%), and shaly coal (15%) and bright lithotypes represented by clarain (23%), vitrain (12%) and a small proportion of wild fire-generated fusain (1%). Maceral analyses revealed the dominance of vitrinite (70.6% on average), followed by liptinite (25.2%) and inertinite (8.1%). Mineral matter content is ～～9% on average and consists of clay, quartz and pyrite concentrate mostly at the base and the roof of the seam. Dominantly vitrinite composition of coal and extremely low fire- and oxidation-borne inertinite content, together with high Gelification Indices imply predomination of waterlogged anoxic conditions in the precursing mire with water tables mostly above the peat surface throughout most of the time during peat swamp formation. Increases in collotelinite contents and Tissue Preservation Index up the section, followed by a reversal trend in upper third of the coal section, further accompanied by a reversal trend in collodetrinite, liptodetrinite, alginite, sporinite and clay contents records a transition from dominately limnotelmatic and limnic at the lower part to dominately limnotelmatic with increase telmatic condition achieved in the middle part of coal. At the upper part of coal seam an opposite trend marks the return to limnic and limnotelmatic conditions in the final phases of peat swamp history and its subsequent inundation. The proportion of arborescent (mostly coniferous) and herbaceous vegetation varied throughout the section of the coal with tendency of increasing density of arborescent vegetation to the middle part of the coal seam section. The intercalation of coal in shallow marine strata implies that peat swamp precursor formed in a coastal setting, probably on delta plain or lagoon. Its formation was controlled by water table changes driven by sea level fluctuations that created an accommodation space necessary for preservation of peat.Edwardson, C.F., Hollibaugh, J.T., 2018. Composition and activity of microbial communities along the redox gradient of an alkaline, hypersaline, lake. Frontiers in Microbiology 9, 14. doi: 10.3389/fmicb.2018.00014. compared the composition of microbial communities obtained by sequencing 16S rRNA gene amplicons with taxonomy derived from metatranscriptomes from the same samples. Samples were collected from alkaline, hypersaline Mono Lake, California, USA at five depths that captured the major redox zones of the lake during the onset of meromixis. The prokaryotic community was dominated by bacteria from the phyla Proteobacteria, Firmicutes, and Bacteroidetes, while the picoeukaryotic chlorophyte Picocystis dominated the eukaryotes. Most (80%) of the abundant (>1% relative abundance) OTUs recovered as amplicons of 16S rRNA genes have been reported in previous surveys, indicating that Mono Lake's microbial community has remained stable over 12 years that have included periods of regular, annual overturn interspersed by episodes of prolonged meromixis that result in extremely reducing conditions in bottom water. Metatranscriptomic sequences binned predominately to the Gammaproteobacteria genera Thioalkalivibrio (4–13%) and Thioalkalimicrobium (0–14%); and to the Firmicutes genera Dethiobacter (0–5%) and Clostridium (1–4%), which were also abundant in the 16S rRNA gene amplicon libraries. This study provides insight into the taxonomic affiliations of transcriptionally active communities of the lake's water column under different redox conditions.Eickmann, B., Hofmann, A., Wille, M., Bui, T.H., Wing, B.A., Schoenberg, R., 2018. Isotopic evidence for oxygenated Mesoarchaean shallow oceans. Nature Geoscience 11, 133-138. fractionation of sulfur isotopes (MIF-S) in Archaean sediments results from photochemical processing of atmospheric sulfur species in an oxygen-depleted atmosphere. Geological preservation of MIF-S provides evidence for microbial sulfate reduction (MSR) in low-sulfate Paleoarchaean (3.8–3.2?billion years ago (Ga)) and Neoarchaean (2.8–2.5?Ga) oceans, but the significance of MSR in Mesoarchaean (3.2–2.8?Ga) oceans is less clear. Here we present multiple sulfur and iron isotope data of early diagenetic pyrites from 2.97-Gyr-old stromatolitic dolomites deposited in a tidal flat environment of the Nsuze Group, Pongola Supergroup, South Africa. We identified consistently negative Δ33S values in pyrite, which indicates photochemical reactions under anoxic atmospheric conditions, but large mass-dependent sulfur isotope fractionations of ~30‰ in δ34S, identifying active MSR. Negative pyrite δ56Fe values (?1.31 to ?0.88‰) record Fe oxidation in oxygen-bearing shallow oceans coupled with biogenic Fe reduction during diagenesis, consistent with the onset of local Fe cycling in oxygen oases ~3.0?Ga. We therefore suggest the presence of oxygenated near-shore shallow-marine environments with ≥5?μM sulfate at this time, in spite of the clear presence of an overall reduced Mesoarchaean atmosphere.Elder, C.D., Xu, X., Walker, J., Schnell, J.L., Hinkel, K.M., Townsend-Small, A., Arp, C.D., Pohlman, J.W., Gaglioti, B.V., Czimczik, C.I., 2018. Greenhouse gas emissions from diverse Arctic Alaskan lakes are dominated by young carbon. Nature Climate Change 8, 166-171. Arctic lakes have been identified as conduits for ancient permafrost-carbon (C) emissions and as such accelerate warming. However, the environmental factors that control emission pathways and their sources are unclear; this complicates upscaling, forecasting and climate-impact-assessment efforts. Here we show that current whole-lake CH4 and CO2 emissions from widespread lakes in Arctic Alaska primarily originate from organic matter fixed within the past 3–4 millennia (modern to 3,300?±?70 years before the present), and not from Pleistocene permafrost C. Furthermore, almost 100% of the annual diffusive C flux is emitted as CO2. Although the lakes mostly processed younger C (89?±?3% of total C emissions), minor contributions from ancient C sources were two times greater in fine-textured versus coarse-textured Pleistocene sediments, which emphasizes the importance of the underlying geological substrate in current and future emissions. This spatially extensive survey considered the environmental and temporal variability necessary to monitor and forecast the fate of ancient permafrost C as Arctic warming progresses.Escobar-Arnanz, J., Mekni, S., Blanco, G., Eljarrat, E., Barceló, D., Ramos, L., 2018. Characterization of organic aromatic compounds in soils affected by an uncontrolled tire landfill fire through the use of comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry. Journal of Chromatography A 1536, 163-175. vehicle tires have become an increasing concern worldwide due to the enormous amount of wastes generated and the increasing evidence of health problems associated to their disposal and accidental combustion. Previous studies conducted involving either simulated or open uncontrolled tire fires have identified aromatics belonging to two main classes, volatile organic compounds and polycyclic aromatic compounds (PAHs), as the most relevant chemicals generated in these burning processes. As a consequence, and due to their recognized toxicity, most studies reported up to now have mainly focused on these two categories of compounds being information concerning the possible occurrence of other aromatic classes rather limited.In this study, the enhanced separation power and structural confirmation capabilities provided by comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC – ToF MS) has been used, for the first time, for the non-targeted analysis of soils impacted by a tire fire and an ash collected at the scene of the fire. In total, 118 volatile and semi-volatile aromatic compounds have been differentiated. Among them, 104 compounds have been either positively or tentatively identified. PAHs with 3–5 rings and their alkyl-derivatives were the most numerous and relevant classes in the investigated samples. A significant number of sulfur, oxygen- and nitrogen-containing PAHs were also detected in the samples. The application of a script function to the raw GC × GC – ToF MS data allowed the fast filtering and automatic recognition of compounds containing halogens in their structure. This part of the study evidenced that only a limited number of regulated persistent organic pollutants were present in the investigated samples. However, it also revealed the presence of emerging organophosphorous flame retardants, whose levels in tire fire impacted soils are reported for the first time.Escudero, C., Vera, M., Oggerin, M., Amils, R., 2018. Active microbial biofilms in deep poor porous continental subsurface rocks. Scientific Reports 8, Article 1538. continental subsurface is defined as oligotrophic environments where microorganisms present a very low metabolic rate. To date, due to the energetic cost of production and maintenance of biofilms, their existence has not been considered in poor porous subsurface rocks. We applied fluorescence in situ hybridization techniques and confocal laser scanning microscopy in samples from a continental deep drilling project to analyze the prokaryotic diversity and distribution and the possible existence of biofilms. Our results show the existence of natural microbial biofilms at all checked depths of the Iberian Pyrite Belt (IPB) subsurface and the co-occurrence of bacteria and archaea in this environment. This observation suggests that multi-species biofilms may be a common and widespread lifestyle in subsurface environments.Eshelman, E., Daly, M.G., Slater, G., Cloutis, E., 2017. Detecting aromatic compounds on planetary surfaces using ultraviolet time-resolved fluorescence spectroscopy. Planetary and Space Science 151, 1-10. aromatic organic molecules exhibit strong and characteristic fluorescence when excited with ultraviolet radiation. As laser excitation in the ultraviolet generates both fluorescence and resonantly enhanced Raman scattering of aromatic vibrational modes, combined Raman and fluorescence instruments have been proposed to search for organic compounds on Mars. In this work the time-resolved fluorescence of a suite of 24 compounds composed of 2–5 ringed alternant, non-alternant, and heterocyclic PAHs was measured. Fluorescence instrumentation with similar specifications to a putative flight instrument was capable of observing the fluorescence decay of these compounds with a sub-ns resolution. Incorporating time-resolved capabilities was also found to increase the ability to discriminate between individual PAHs. Incorporating time-resolved fluorescence capabilities into an ultraviolet gated Raman system intended for a rover or lander can increase the ability to detect and characterize PAHs on planetary surfaces.Eskelsen, J.R., Xu, J., Chiu, M., Moon, J.-W., Wilkins, B., Graham, D.E., Gu, B., Pierce, E.M., 2018. Influence of structural defects on biomineralized ZnS nanoparticle dissolution: An in-situ electron microscopy study. Environmental Science & Technology 52, 1139-1149. dissolution of metal sulfides, such as ZnS, is an important biogeochemical process affecting fate and transport of trace metals in the environment. However, current studies of in situ dissolution of metal sulfides and the effects of structural defects on dissolution are lacking. Here we have examined the dissolution behavior of ZnS nanoparticles synthesized via several abiotic and biological pathways. Specifically, we have examined biogenic ZnS nanoparticles produced by an anaerobic, metal-reducing bacterium Thermoanaerobacter sp. X513 in a Zn-amended, thiosulfate-containing growth medium in the presence or absence of silver (Ag), and abiogenic ZnS nanoparticles were produced by mixing an aqueous Zn solution with either H2S-rich gas or Na2S solution. The size distribution, crystal structure, aggregation behavior, and internal defects of the synthesized ZnS nanoparticles were examined using high-resolution transmission electron microscopy (TEM) coupled with X-ray energy dispersive spectroscopy. The characterization results show that both the biogenic and abiogenic samples were dominantly composed of sphalerite. In the absence of Ag, the biogenic ZnS nanoparticles were significantly larger (i.e., ～10 nm) than the abiogenic ones (i.e., ～3–5 nm) and contained structural defects (e.g., twins and stacking faults). The presence of trace Ag showed a restraining effect on the particle size of the biogenic ZnS, resulting in quantum-dot-sized nanoparticles (i.e., ～3 nm). In situ dissolution experiments for the synthesized ZnS were conducted with a liquid-cell TEM (LCTEM), and the primary factors (i.e., the presence or absence structural defects) were evaluated for their effects on the dissolution behavior using the biogenic and abiogenic ZnS nanoparticle samples with the largest average particle size. Analysis of the dissolution results (i.e., change in particle radius with time) using the Kelvin equation shows that the defect-bearing biogenic ZnS nanoparticles (γ = 0.799 J/m2) have a significantly higher surface energy than the abiogenic ZnS nanoparticles (γ = 0.277 J/m2). Larger defect-bearing biogenic ZnS nanoparticles were thus more reactive than the smaller quantum-dot-sized ZnS nanoparticles. These findings provide new insight into the factors that affect the dissolution of metal sulfide nanoparticles in relevant natural and engineered scenarios, and have important implications for tracking the fate and transport of sulfide nanoparticles and associated metal ions in the environment. Moreover, our study exemplified the use of an in situ method (i.e., LCTEM) to investigate nanoparticle behavior (e.g., dissolution) in aqueous solutions.Evans, D., Sagoo, N., Renema, W., Cotton, L.J., Müller, W., Todd, J.A., Saraswati, P.K., Stassen, P., Ziegler, M., Pearson, P.N., Valdes, P.J., Affek, H.P., 2018. Eocene greenhouse climate revealed by coupled clumped isotope-Mg/Ca thermometry. Proceedings of the National Academy of Sciences 115, 1174-1179.: Reconstructing the degree of warming during geological periods of elevated CO2 provides a way of testing our understanding of the Earth system and the accuracy of climate models. We present accurate estimates of tropical sea-surface temperatures (SST) and seawater chemistry during the Eocene (56–34 Ma before present, CO2 >560 ppm). This latter dataset enables us to reinterpret a large amount of existing proxy data. We find that tropical SST are characterized by a modest warming in response to CO2. Coupling these data to a conservative estimate of high-latitude warming demonstrates that most climate simulations do not capture the degree of Eocene polar amplification. Abstract: Past greenhouse periods with elevated atmospheric CO2 were characterized by globally warmer sea-surface temperatures (SST). However, the extent to which the high latitudes warmed to a greater degree than the tropics (polar amplification) remains poorly constrained, in particular because there are only a few temperature reconstructions from the tropics. Consequently, the relationship between increased CO2, the degree of tropical warming, and the resulting latitudinal SST gradient is not well known. Here, we present coupled clumped isotope (Δ47)-Mg/Ca measurements of foraminifera from a set of globally distributed sites in the tropics and midlatitudes. Δ47 is insensitive to seawater chemistry and therefore provides a robust constraint on tropical SST. Crucially, coupling these data with Mg/Ca measurements allows the precise reconstruction of Mg/Casw throughout the Eocene, enabling the reinterpretation of all planktonic foraminifera Mg/Ca data. The combined dataset constrains the range in Eocene tropical SST to 30–36 °C (from sites in all basins). We compare these accurate tropical SST to deep-ocean temperatures, serving as a minimum constraint on high-latitude SST. This results in a robust conservative reconstruction of the early Eocene latitudinal gradient, which was reduced by at least 32 ± 10% compared with present day, demonstrating greater polar amplification than captured by most climate models. Ezeonyeka, N.L., Hemmati-Sarapardeh, A., Husein, M.M., 2018. Asphaltenes adsorption onto metal oxide nanoparticles: A critical evaluation of measurement techniques. Energy & Fuels 32, 2213-2223. adsorption of asphaltenes onto nanoparticles (NPs) has received a lot of attention in recent years. However, the effect of the measurement technique on the adsorption isotherms has never been addressed. In this paper, the adsorption of n-heptane-precipitated asphaltenes, C7-asphaltenes, from toluene model solutions onto three metal oxide NPs, namely Fe2O3, Fe3O4, and Al2O3, was studied. Asphaltenes uptake calculated from UV–vis spectroscopy at three different wavelengths were compared with thermogravimetric analysis (TGA) results. Although the adsorption trends followed Langmuir isotherms, instrument as well as wavelength-dependent coefficients were obtained. We believe TGA results are more reliable, provided complete oxidation and account of mass loss due to NPs is attained. UV–vis measurements may be impacted by the chemical structure of the asphaltenes sub fractions as well as their state of association. Al2O3 showed the highest adsorption capacity of 385 ± 5 mg/g, followed by Fe3O4 and Fe2O3. However, based on mg/m2, Fe2O3 displayed the highest adsorption capacity. TGA analysis revealed that the NPs promoted the oxidation of adsorbed asphaltenes in a reverse order to their adsorption capacity, qmax (mg/g) (Al2O3 > Fe2O3 ≈ Fe3O4). This trend is in line with our previous observation of mass-dependent thermo-oxidative profile and surface exposure role, rather than a catalyst role, of the NPs. Lastly, the C7-asphaltenes from this study were characterized, and their structural parameters were compared to 45 asphaltenes from the literature. The size and structural parameters of the asphaltenes clusters are in good agreement with the literature values.Fairén, A.G., Parro, V., Schulze-Makuch, D., Whyte, L., 2018. Is searching for martian life a priority for the Mars community? Astrobiology 18, 101-107. article. No abstractFamiano, M.A., Boyd, R.N., Kajino, T., Onaka, T., 2018. Selection of amino acid chirality via neutrino interactions with 14N in crossed electric and magnetic fields. Astrobiology 18, 190-206. work has suggested that the chirality of the amino acids could be established in the magnetic field of a nascent neutron star from a core-collapse supernova or massive collapsar. The magnetic field would orient the 14N nuclei, and the alignment of its nuclear spin with respect to those of the electron antineutrinos emitted from the collapsing star would determine the probability of destruction of the 14N nuclei by interactions with the antineutrinos. Subsequent work estimated the bulk polarization of the 14N nuclei in large rotating meteoroids in such an environment.The present work adds a crucial piece of this model by describing the details by which the selective 14N nuclear destruction would produce molecular chiral selectivity. The effects of the neutrino-induced interactions on the 14N nuclei bound in amino acids polarized in strong magnetic fields are studied. It is shown that electric fields in the reference frame of the nuclei modify the magnetic field at the nucleus, creating nuclear magnetizations that are asymmetric in chirality. The antineutrino cross sections depend on this magnetization, creating a selective destructive effect. The environmental conditions and sites in which such a selection mechanism could occur are discussed. Selective destruction of D-enantiomers results in enantiomeric excesses which may be sufficient to drive subsequent autocatalysis necessary to produce the few-percent enantiomeric excesses found in meteorites and subsequent homochirality.Molecular quantum chemical calculations were performed for alanine, and the chirality-dependent effects studied were included. A preference for left-handed molecules was found, and enantiomeric excesses as high as 0.02% were estimated for molecules in the electromagnetic conditions expected from a core-collapse supernova.Fantasia, A., F?llmi, K.B., Adatte, T., Spangenberg, J.E., Montero-Serrano, J.-C., 2018. The Early Toarcian oceanic anoxic event: Paleoenvironmental and paleoclimatic change across the Alpine Tethys (Switzerland). Global and Planetary Change 162, 53-68. and paleoclimatic change associated with the Toarcian oceanic anoxic event (T-OAE) was evaluated in five successions located in Switzerland. They represent different paleogeographic settings across the Alpine Tethys: the northern shelf (Gipf, Riniken and Rietheim), the Sub-Brian?onnais basin (Creux de l'Ours), and the Lombardian basin (Breggia). The multi-proxy approach chosen (whole-rock and clay mineralogy, phosphorus, major and trace elements) shows that local environmental conditions modulated the response to the T-OAE across the Alpine Tethys. On the northern shelf and in the Sub-Brian?onnais basin, high kaolinite contents and detrital proxies (detrital index, Ti, Zr, Si) in the T-OAE interval suggest a change towards a warmer and more humid climate coupled with an increase in the chemical weathering rates. In contrast, low kaolinite content in the Lombardian basin is likely related to a more arid climate along the southern Tethys margin and/or to a deeper and more distal setting. Redox-sensitive trace-element (V, Mo, Cu, Ni) enrichments in the T-OAE intervals reveal that dysoxic to anoxic conditions developed on the northern shelf, whereas reducing conditions were less severe in the Sub-Brian?onnais basin. In the Lombardian basin well-oxygenated bottom water conditions prevailed. Phosphorus (P) speciation analysis was performed at Riniken and Creux de l'Ours. This is the first report of P speciation data for T-OAE sections, clearly suggesting that high P contents during this time interval are mainly linked to the presence of an authigenic phases and fish remains. The development of oxygen-depleted conditions during the T-OAE seems to have promoted the release of the organic-bound P back into the water column, thereby further sustaining primary productivity in a positive feedback loop.Feng, D., Peckmann, J., Li, N., Kiel, S., Qiu, J.-W., Liang, Q., Carney, R.S., Peng, Y., Tao, J., Chen, D., 2018. The stable isotope fingerprint of chemosymbiosis in the shell organic matrix of seep-dwelling bivalves. Chemical Geology 479, 241-250. bivalves harboring endosymbiotic, chemotrophic bacteria have been investigated from a variety of hydrocarbon seeps worldwide. It has been shown that carbon, nitrogen, and sulfur isotopic compositions of the animal soft body parts are excellent indicators for evaluating energy transfer and food sources for the respective deep-sea habitats. However, recognition of chemosymbiosis has proven to be difficult for bivalves that dwelled at ancient seeps due to the lack of soft tissue. Here, we investigated δ13C, δ15N, and δ34S signatures of the tissue (mantle) and the shell organic matrix (SOM) of the same specimens of three bathymodiolin mussel species with different chemotrophic symbionts (methanotrophs in Bathymodiolus platifrons and B. childressi and thiotrophs in B. aduloides) and one vesicomyid clam (Calyptogena sp.) from a variety of hydrocarbon seeps from the South China Sea and the Gulf of Mexico. The data obtained demonstrate that all seep bivalves regardless of species or locations reveal overall small differences in δ13C (≤+4‰), δ15N (≤+1‰), and δ34S (≤+5‰) values between SOM and mantle (?SOM-mantle) of the specimens. Relatively larger ?SOM-mantle for δ13C values (as high as +10‰) in B. platifrons and larger ?SOM-mantle for δ34S values (up to 16‰) in B. aduloides and Calyptogena sp. might be due to different symbionts in their gills. Since SOM can be extracted from fossil bivalve shells, the proxy can be used as a fingerprint of chemosynthesis-based food chains, although its utility will depend on the quality of preservation of the shell organic matter. Despite this uncertainty, the new proxy has great potential to reconstruct energy flow through different types of chemosynthesis-based ecosystems.Filla, R.T., Schrell, A.M., Coulton, J.B., Edwards, J.L., Roper, M.G., 2018. Frequency-modulated continuous flow analysis electrospray ionization mass spectrometry (FM-CFA-ESI-MS) for sample multiplexing. Analytical Chemistry 90, 2414-2419. method for multiplexed sample analysis by mass spectrometry without the need for chemical tagging is presented. In this new method, each sample is pulsed at unique frequencies, mixed, and delivered to the mass spectrometer while maintaining a constant total flow rate. Reconstructed ion currents are then a time-dependent signal consisting of the sum of the ion currents from the various samples. Spectral deconvolution of each reconstructed ion current reveals the identity of each sample, encoded by its unique frequency, and its concentration encoded by the peak height in the frequency domain. This technique is different from other approaches that have been described, which have used modulation techniques to increase the signal-to-noise ratio of a single sample. As proof of concept of this new method, two samples containing up to 9 analytes were multiplexed. The linear dynamic range of the calibration curve was increased with extended acquisition times of the experiment and longer oscillation periods of the samples. Because of the combination of the samples, salt had little effect on the ability of this method to achieve relative quantitation. Continued development of this method is expected to allow for increased numbers of samples that can be multiplexed.Fischer, C., Luttge, A., 2018. Pulsating dissolution of crystalline matter. Proceedings of the National Academy of Sciences 115, 897-902.: The reaction of crystalline material with fluids is of relevance for natural and technical processes. A basic assumption has been that the reaction products are continuously released from the crystal surface. New experimental and analytical results show something fundamentally different: Material is released in a series of reaction pulses. Applied and theoretical implications impact both the upscaling of crystal dissolution kinetics, and more importantly, the problem of how dissolution and growth are connected via the equilibrium state. These results challenge the prevailing view that crystal dissolution is simply the inverse process of continuous crystal growth at crystal dislocations. Consequently, we need to examine how macroscopic crystal equilibrium reflects continuous or discontinuous processes in the microscopic state.Abstract: Fluid–solid reactions result in material flux from or to the solid surface. The prediction of the flux, its variations, and changes with time are of interest to a wide array of disciplines, ranging from the material and earth sciences to pharmaceutical sciences. Reaction rate maps that are derived from sequences of topography maps illustrate the spatial distribution of reaction rates across the crystal surface. Here, we present highly spatially resolved rate maps that reveal the existence of rhythmic pulses of the material flux from the crystal surface. This observation leads to a change in our understanding of the way crystalline matter dissolves. Rhythmic fluctuations of the reactive surface site density and potentially concomitant oscillations in the fluid saturation imply spatial and temporal variability in surface reaction rates. Knowledge of such variability could aid attempts to upscale microscopic rates and predict reactive transport through changing porous media.Fitzek, E., Joardar, A., Gupta, R., Geisler, M., 2018. Evolution of eukaryal and archaeal pseudouridine synthase Pus10. Journal of Molecular Evolution 86, 77-89. archaea, pseudouridine (Ψ) synthase Pus10 modifies uridine (U) to Ψ at positions 54 and 55 of tRNA. In contrast, Pus10 is not found in bacteria, where modifications at those two positions are carried out by TrmA (U54 to m5U54) and TruB (U55 to Ψ55). Many eukaryotes have an apparent redundancy; their genomes contain orthologs of archaeal Pus10 and bacterial TrmA and TruB. Although eukaryal Pus10 genes share a conserved catalytic domain with archaeal Pus10 genes, their biological roles are not clear for the two reasons. First, experimental evidence suggests that human Pus10 participates in apoptosis induced by the tumor necrosis factor-related apoptosis-inducing ligand. Whether the function of human Pus10 is in place or in addition to of Ψ synthesis in tRNA is unknown. Second, Pus10 is found in earlier evolutionary branches of fungi (such as chytrid Batrachochytrium) but is absent in all dikaryon fungi surveyed (Ascomycetes and Basidiomycetes). We did a comprehensive analysis of sequenced genomes and found that orthologs of Pus10, TrmA, and TruB were present in all the animals, plants, and protozoa surveyed. This indicates that the common eukaryotic ancestor possesses all the three genes. Next, we examined 116 archaeal and eukaryotic Pus10 protein sequences to find that Pus10 existed as a single copy gene in all the surveyed genomes despite ancestral whole genome duplications had occurred. This indicates a possible deleterious gene dosage effect. Our results suggest that functional redundancy result in gene loss or neofunctionalization in different evolutionary lineages.Fonseca, C., Mendon?a, J.O., Mendon?a Filho, J.G., Lézin, C., Duarte, L.V., 2018. Thermal maturity assessment study of the late Pliensbachian-early Toarcian organic-rich sediments in southern France: Grands Causses, Quercy and Pyrenean basins. Marine and Petroleum Geology 91, 338-349. maturity of late Pliensbachian-early Toarcian organic-rich sediments in the Grands Causses (Suèges section), Quercy (Caylus section) and Pyrenean (Pont de Suert section) basins was determined through multiple parameters, including Spore Coloration Index (SCI), hydroid random reflectance (HRr) and spectral fluorescence of Tasmanites algae (λmax). The main objective of this study is to test the effectiveness and make comparisons of organic matter thermal maturity in these three sections by different techniques and particularly hydroid reflectance.For the Suèges section SCI presented a value of 3.5–4.0. HRr ranges between 0.36% and 0.47%, which corresponds to 0.45%–0.52% VReq, and shows a good correlation with SCI values. Spectral fluorescence analysis presents a λmax of 560?nm for most samples. The fluorescence spectral maximum seems to be redshifted in comparison to other thermal maturity parameters.The Caylus section exhibited SCI of 3.5–4.0. HRr ranges between 0.32% and 0.50% corresponding to 0.42%–0.54% VReq. Spectral fluorescence analysis points out a λmax of 560?nm, displaying a good correlation with SCI. When Req values determined through SCI are compared with equivalent vitrinite reflectance values determined through λmax, a redshift of the fluorescence spectrum maximum is detected.For the Pont de Suert section SCI ranges between 8.0-8.5 and 8.5–9.0. HRr varies between 0.85% and 1.18% which corresponds to 0.76%–0.98% VReq. Even though there are lower values than those obtained by SCI, VReq is reliable and acceptable to determine the thermal evolution stage. Furthermore, HRr values also present a good correlation with SCI.These data indicate that the majority of the samples from the Suèges and Caylus sections are in the immature to early mature evolution stages and Pont de Suert section samples are in late mature to early overmature evolution stages for liquid hydrocarbons generation, supporting a very similar thermal evolution for the Grands Causses and Quercy basins and an entirely different thermal history for the Pyrenean Basin. This is in accordance with the similar tectonic and sedimentary context of the Quercy and Grands Causses basins. The Pont de Suert section, located near the collision front of the Pyrenees mountains, records a more complex sedimentary and tectonic history. In addition, this study presents the first reflectance data for Jurassic hydroids, which show a good correlation with other rank parameters.Fortunato, C.S., Larson, B., Butterfield, D.A., Huber, J.A., 2018. Spatially distinct, temporally stable microbial populations mediate biogeochemical cycling at and below the seafloor in hydrothermal vent fluids. Environmental Microbiology 20, 769-784. deep-sea hydrothermal vents, microbial communities thrive across geochemical gradients above, at, and below the seafloor. In this study, we determined the gene content and transcription patterns of microbial communities and specific populations to understand the taxonomy and metabolism both spatially and temporally across geochemically different diffuse fluid hydrothermal vents. Vent fluids were examined via metagenomic, metatranscriptomic, genomic binning, and geochemical analyses from Axial Seamount, an active submarine volcano on the Juan de Fuca Ridge in the NE Pacific Ocean, from 2013 to 2015 at three different vents: Anemone, Marker 33, and Marker 113. Results showed that individual vent sites maintained microbial communities and specific populations over time, but with spatially distinct taxonomic, metabolic potential, and gene transcription profiles. The geochemistry and physical structure of each vent both played important roles in shaping the dominant organisms and metabolisms present at each site. Genomic binning identified key populations of SUP05, Aquificales and methanogenic archaea carrying out important transformations of carbon, sulfur, hydrogen, and nitrogen, with groups that appear unique to individual sites. This work highlights the connection between microbial metabolic processes, fluid chemistry, and microbial population dynamics at and below the seafloor and increases understanding of the role of hydrothermal vent microbial communities in deep ocean biogeochemical cycles.Fouquet, T., Satoh, T., Sato, H., 2018. First gut instincts are always right: The resolution required for a mass defect analysis of polymer ions can be as low as oligomeric. Analytical Chemistry 90, 2404-2408. recent adaptation to low-resolution mass spectra of polymers using fractional base units raises the question of the minimal resolution needed for a Kendrick mass defect (KMD) analysis. Intuiting an oligomeric resolution since the mass of a repeat unit is the sole value to be known, it is challenged by the relative failure of the KMD plots computed from an isotopically resolved matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrum to display clear alignments in the high mass range. Another procedure based on the remainders of Kendrick mass (RKMs) overcomes this pitfall with oligomers perfectly aligned in a new RKM plot. Despite a concomitant degradation of the resolving power and accuracy, with the example of MALDI-TOF/TOF mass spectra of a variety of homo- and copolymer ions, the RKM procedure still allows a rapid enumeration, assignment, and any further manipulation of all the product ion series in visual RKM plots. Successfully extended to the critical case of a MALDI mass spectrum recorded with a linear TOF analyzer allowing a bare oligomeric resolution, the RKM plot turns the distributions differing by their end-groups or adducted ion into clear horizontal lines. It eventually gives intuition its due by answering the original question: the minimal resolution required for a mass defect analysis can be as low as oligomeric with the appropriate formulas.Freye, C.E., Moore, N.R., Synovec, R.E., 2018. Enhancing the chemical selectivity in discovery-based analysis with tandem ionization time-of-flight mass spectrometry detection for comprehensive two-dimensional gas chromatography. Journal of Chromatography A 1537, 99-108. complementary information provided by tandem ionization time-of-flight mass spectrometry (TI-TOFMS) is investigated for comparative discovery-based analysis, when coupled with comprehensive two-dimensional gas chromatography (GC?×?GC). The TI conditions implemented were a hard ionization energy (70?eV) concurrently collected with a soft ionization energy (14?eV). Tile-based Fisher ratio (F-ratio) analysis is used to analyze diesel fuel spiked with twelve analytes at a nominal concentration of 50?ppm. F-ratio analysis is a supervised discovery-based technique that compares two different sample classes, in this case spiked and unspiked diesel, to reduce the complex GC?×?GC-TI-TOFMS data into a hit list of class distinguishing analyte features. Hit lists of the 70?eV and 14?eV data sets, and the single hit list produced when the two data sets are fused together, are all investigated. For the 70?eV hit list, eleven of the twelve analytes were found in the top thirteen hits. For the 14?eV hit list, nine of the twelve analytes were found in the top nine hits, with the other three analytes either not found or well down the hit list. As expected, the F-ratios per m/z used to calculate each average F-ratio per hit were generally smaller fragment ions for the 70?eV data set, while the larger fragment ions were emphasized in the 14?eV data set, supporting the notion that complementary information was provided. The discovery rate was improved when F-ratio analysis was performed on the fused data sets resulted in eleven of the twelve analytes being at the top of the single hit list. Using PARAFAC, analytes that were “discovered” were deconvoluted in order to obtain their identification via match values (MV). Location of the analytes and the “F-ratio spectra” obtained from F-ratio analysis were used to guide the deconvolution. Eight of the twelve analytes where successfully deconvoluted and identified using the in-house library for the 70?eV data set. PARAFAC deconvolution of the two separate data sets provided increased confidence in identification of “discovered” analytes. Herein, we explore the limit of analyte discovery and limit of analyte identification, and demonstrate a general workflow for the investigation of key chemical features in complex samples.Froese, T., Campos, J.I., Fujishima, K., Kiga, D., Virgo, N., 2018. Horizontal transfer of code fragments between protocells can explain the origins of the genetic code without vertical descent. Scientific Reports 8, Article 3532. of the origin of the genetic code typically appeal to natural selection and/or mutation of hereditable traits to explain its regularities and error robustness, yet the present translation system presupposes high-fidelity replication. Woese’s solution to this bootstrapping problem was to assume that code optimization had played a key role in reducing the effect of errors caused by the early translation system. He further conjectured that initially evolution was dominated by horizontal exchange of cellular components among loosely organized protocells (“progenotes”), rather than by vertical transmission of genes. Here we simulated such communal evolution based on horizontal transfer of code fragments, possibly involving pairs of tRNAs and their cognate aminoacyl tRNA synthetases or a precursor tRNA ribozyme capable of catalysing its own aminoacylation, by using an iterated learning model. This is the first model to confirm Woese’s conjecture that regularity, optimality, and (near) universality could have emerged via horizontal interactions alone.Frouin, E., Bes, M., Ollivier, B., Quéméneur, M., Postec, A., Debroas, i., Armougom, F., Erauso, G., 2018. Diversity of rare and abundant prokaryotic phylotypes in the Prony Hydrothermal Field and comparison with other serpentinite-hosted ecosystems. Frontiers in Microbiology 9, 102. doi: 10.3389/fmicb.2018.00102. Bay of Prony, South of New Caledonia, represents a unique serpentinite-hosted hydrothermal field due to its coastal situation. It harbors both submarine and intertidal active sites, discharging hydrogen- and methane-rich alkaline fluids of low salinity and mild temperature through porous carbonate edifices. In this study, we have extensively investigated the bacterial and archaeal communities inhabiting the hydrothermal chimneys from one intertidal and three submarine sites by 16S rRNA gene amplicon sequencing. We show that the bacterial community of the intertidal site is clearly distinct from that of the submarine sites with species distribution patterns driven by only a few abundant populations, affiliated to the Chloroflexi and Proteobacteria phyla. In contrast, the distribution of archaeal taxa seems less site-dependent, as exemplified by the co-occurrence, in both submarine and intertidal sites, of two dominant phylotypes of Methanosarcinales previously thought to be restricted to serpentinizing systems, either marine (Lost City Hydrothermal Field) or terrestrial (The Cedars ultrabasic springs). Over 70% of the phylotypes were rare and included, among others, all those affiliated to candidate divisions. We finally compared the distribution of bacterial and archaeal phylotypes of Prony Hydrothermal Field with those of five previously studied serpentinizing systems of geographically distant sites. Although sensu stricto no core microbial community was identified, a few uncultivated lineages, notably within the archaeal order Methanosarcinales and the bacterial class Dehalococcoidia (the candidate division MSBL5) were exclusively found in a few serpentinizing systems while other operational taxonomic units belonging to the orders Clostridiales, Thermoanaerobacterales, or the genus Hydrogenophaga, were abundantly distributed in several sites. These lineages may represent taxonomic signatures of serpentinizing ecosystems. These findings extend our current knowledge of the microbial diversity inhabiting serpentinizing systems and their biogeography.Fuertez, J., Córdoba, G., McLennan, J.D., Adams, D.J., Sparks, T.D., 2018. Potential application of developed methanogenic microbial consortia for coal biogasification. International Journal of Coal Geology 188, 165-180. enhanced coalbed methane has become an important research topic in the later years. The biological conversion of coal to methane can be conceived as a feasible and environmental friendly approach for improving coalbed methane production. Within the strategies for stimulation of gas production, the addition of a microbial consortium or bioaugmentation can be seen as a promising alternative. However, relatively few studies have been conducted on the strategies for enriching microbial population ex-situ under initial atmospheric exposure for subsequent injection into coal seams to stimulate biodegradation and methanogenesis. The development of methanogenic microbial consortia, especially those that can tolerate moderate and low oxygen concentrations and still retain anaerobic functionality, can be considered as an attractive biological complement for coal biogasification. The performance of promising microbial consortia was evaluated at low concentrations of nutrient amendments (e.g., 22.4% v/v, 3.36?mg/cm3 TSB) and [NaCl] 6.6?mg/cm3 as a possible scenario and to foresee the elevated costs of nutrient utilization at large-scale operations (i.e., in-situ and/or ex-situ applications). Incubation periods of up to four months were tested at 23?°C. Headspace concentrations of CH4 and CO2 were analyzed by gas chromatography. After 61?days of incubation for the most promising microbial samples, generated headspace gas concentrations reached 95,700?ppm (14?sft3/ton) for methane and 37,560?ppm (5.5?sft3/ton) for carbon dioxide. Microbial diversity in promising consortia was investigated. Both bacteria and archaea were identified.Furukawa, Y., Takase, A., Sekine, T., Kakegawa, T., Kobayashi, T., 2018. Racemization of valine by impact-induced heating. Origins of Life and Evolution of Biospheres 48, 131-139. plays an important role in all living organisms but its origin remains unclear. It also remains unclear whether such chiral molecules survived terrestrial heavy impact events. Impacts of extraterrestrial objects on early oceans were frequent and could have affected the chirality of oceanic amino acids when such amino acids accumulated during impacts. This study investigated the effects of shock-induced heating on enantiomeric change of valine with minerals such as olivine ([Mg0.9, Fe0.1]2SiO4), hematite (Fe2O3), and calcite (CaCO3). With a shock wave generated by an impact at ~0.8?km/s, both D- and L-enriched valine were significantly decomposed and partially racemized under all experimental conditions. Different minerals had different shock impedances; therefore, they provided different P-T conditions for identical impacts. Furthermore, the high pH of calcite promoted the racemization of valine. The results indicate that in natural hypervelocity impacts, amino acids in shocked oceanic water would have decomposed completely, since impact velocity and the duration of shock compression and heating are typically greater in hypervelocity impact events than those in experiments. Even with the shock wave by the impact of small and decelerated projectiles in which amino acids survive, the shock heating may generate sufficient heat for significant racemization in shocked oceanic water. However, the duration of shock induced heating by small projectiles is limited and the population of such decelerated projectiles would be limited. Therefore, even though impacts of asteroids and meteorites were frequent on the prebiotic Earth, impact events would not have significantly changed the ee of proteinogenic amino acids accumulated in the entire ocean.Gan, H., Wang, H., Chen, J., Zhuang, X., Cao, H., Jiang, S., 2018. Geochemical characteristics of Jurassic coal and its paleoenvironmental implication in the eastern Junggar Basin, China. Journal of Geochemical Exploration 188, 73-86. study is the first to provide geochemical and paleoenvironmental information of Jurassic Xishanyao Formation coal in the eastern Junggar Basin, China. Twenty-seven coal core samples were collected from the zk0413 boreholes in Dajing area to determine the geochemical variability. Proximate analyses show that the Xishanyao Formation coal has the medium moisture content (average 13%), special low ash yield (average 6%) and high volatile matter (average 34%), which slightly fluctuate from bottom to top of coal seam. Organic matter in the coal are type III kerogen, with coalification degrees determined as subbituminous A or high volatile bituminous C. All coal samples have poor hydrocarbon generating potential with the yield between 31.93 and 72.36 (average of 43.57)?mg?HC/g.rock. The primary input of organic matter for coal-formation was higher terrestrial plants, with greater input from algae and micro-organisms and greater role of bacteria in plant degradation higher in the seam. The process of peatification in the lower section of the seam occurred under more acidic and oxic conditions. Coal accumulated in a lacustrine freshwater environment with the rise of the (ground) water table from bottom to top. There is evidence of higher salinity of water within the lower seam and decreased salinity (brackish to fresh water) within the middle of the seam, then an increase to moderate salinity (fresh water to brackish). The increasing stratified water column upward with reduced oxidation in the coal seams may result from the increased temperature in periods of a relatively hot and dry climate. The environment changes demonstrated in this study illustrate the importance of studying combined elemental and organic geochemistry to reconstruct paleoenvironment.Gao, G., Zhang, G., Chen, G., Gang, W., Shen, H., Zhao, K., 2018. Geochemistry of borehole cutting shale and natural gas accumulation in the deepwater area of the Zhujiang River Mouth-Qiongdongnan Basin in the northern South China Sea. Acta Oceanologica Sinica 37, 44-53. Qiongdongnan Basin and Zhujiang River (Pearl River) Mouth Basin, important petroliferous basins in the northern South China Sea, contain abundant oil and gas resource. In this study, on basis of discussing impact of oil-base mud on TOC content and Rock-Eval parameters of cutting shale samples, the authors did comprehensive analysis of source rock quality, thermal evolution and control effect of source rock in gas accumulation of the Qiongdongnan and the Zhujiang River Mouth Basins. The contrast analysis of TOC contents and Rock-Eval parameters before and after extraction for cutting shale samples indicates that except for a weaker impact on Rock-Eval parameter S2, oil-base mud has certain impact on Rock-Eval S1, Tmax and TOC contents. When concerning oil-base mud influence on source rock geochemistry parameters, the shales in the Yacheng/Enping, Lingshui/Zhuhai and Sanya/Zhuhai Formations have mainly Type II and III organic matter with better gas potential and oil potential. The thermal evolution analysis suggests that the depth interval of the oil window is between 3 000 m and 5 000 m. Source rocks in the deepwater area have generated abundant gas mainly due to the late stage of the oil window and the high-supper mature stage. Gas reservoir formation condition analysis made clear that the source rock is the primary factor and fault is a necessary condition for gas accumulation. Spatial coupling of source, fault and reservoir is essential for gas accumulation and the inside of hydrocarbon-generating sag is future potential gas exploration area.Gao, Y., Zhang, X., Zhang, G., Chen, K., Shen, Y., 2018. Ediacaran negative C-isotopic excursions associated with phosphogenic events: Evidence from South China. Precambrian Research 307, 218-228. Yangtze platform of South China preserves relatively continuous strata of the Ediacaran Period and has been one of the key areas to explore Neoproterozoic Earth history. In this study, high-resolution carbon isotope (δ13C) and oxygen isotope (δ18O) data of 701 samples were reported for sedimentary rocks spanning the entire Ediacaran Period using a continuous drill core collected from Wangji, South China. The C-isotopic data of the Doushantuo Formation are consistent with previous work, showing three negative δ13C excursions that can be correlated intra-basinally. A large negative δ13C excursion from +8.16‰ to ?7.20‰ identified at the top of the Doushantuo Formation, which is equivalent to the “Shuram Negative Excursion”, allows us to correlate the δ13C profile globally. In the overlying Dengying Formation, we identified two distinct δ13C intervals with an average value of +3.32‰ and of?+0.40‰, respectively. As well, we observed a negative δ13C excursion in the middle Dengying Formation, which has not been reported previously.Three major negative δ13C excursions, two in the Doushantuo Formation and one in the Dengying Formation, are tightly associated with phosphorite deposits. The temporal correlation between the negative δ13C excursions and the phosphorite deposits suggests a potential link between carbon and phosphorus cycling in the Ediacaran oceans. We argue that multiple periods of strong upwelling may have played an important role in C and P cycling in the Ediacaran oceans. Oxidative processes of the 13C-depleted dissolved organic carbon (DOC) transported into oxic near-surface waters by upwelling resulted in the negative δ13C excursions, and contributed to synchronous burial of abundant phosphorites in the inner shelf areas. The different magnitudes of the negative δ13C excursions observed in the Doushantuo and Dengying formations may reflect spatial changes of DOC reservoir and variations of upwelling intensity and mixing processes.García-Cruz, N.U., Sánchez-Avila, J.I., Valdés-Lozano, D., Gold-Bouchot, G., Aguirre-Macedo, L., 2018. Biodegradation of hexadecane using sediments from rivers and lagoons of the Southern Gulf of Mexico. Marine Pollution Bulletin 128, 202-207. Southern Gulf of Mexico is an area highly impacted by crude oil extraction, refining activities and the presence of natural petroleum seepage. Oceanic currents in the Gulf of Mexico continually facilitate the transport of hydrocarbons to lagoons and rivers. This research evaluated hexadecane (HXD) degradation in marine sediment samples from lagoons and rivers that are fed by the Southern Gulf of Mexico, specifically six samples from rivers, three samples from lagoons, and one sample from a marine outfall. The highest rates of biodegradation were observed in sediments from the mouths of the Gonzalez River and the Champotón Lagoon. The lowest consumption rate was found in sediment from the mouth of the Coatzacoalcos River. With regards to the Ostión Lagoon and the Grijalva River, there was a low rate of consumption, but a high efficiency of degradation which took place at the end of the experiments. No correlation was found between the consumption rate and the environmental physicochemical parameters.Garrido-Sanz, D., Manzano, J., Martín, M., Redondo-Nieto, M., Rivilla, R., 2018. Metagenomic analysis of a biphenyl-degrading soil bacterial consortium reveals the metabolic roles of specific populations. Frontiers in Microbiology 9, 232. doi: 10.3389/fmicb.2018.00232. biphenyls (PCBs) are widespread persistent pollutants that cause several adverse health effects. Aerobic bioremediation of PCBs involves the activity of either one bacterial species or a microbial consortium. Using multiple species will enhance the range of PCB congeners co-metabolized since different PCB-degrading microorganisms exhibit different substrate specificity. We have isolated a bacterial consortium by successive enrichment culture using biphenyl (analog of PCBs) as the sole carbon and energy source. This consortium is able to grow on biphenyl, benzoate, and protocatechuate. Whole-community DNA extracted from the consortium was used to analyze biodiversity by Illumina sequencing of a 16S rRNA gene amplicon library and to determine the metagenome by whole-genome shotgun Illumina sequencing. Biodiversity analysis shows that the consortium consists of 24 operational taxonomic units (≥97% identity). The consortium is dominated by strains belonging to the genus Pseudomonas, but also contains betaproteobacteria and Rhodococcus strains. whole-genome shotgun (WGS) analysis resulted in contigs containing 78.3 Mbp of sequenced DNA, representing around 65% of the expected DNA in the consortium. Bioinformatic analysis of this metagenome has identified the genes encoding the enzymes implicated in three pathways for the conversion of biphenyl to benzoate and five pathways from benzoate to tricarboxylic acid (TCA) cycle intermediates, allowing us to model the whole biodegradation network. By genus assignment of coding sequences, we have also been able to determine that the three biphenyl to benzoate pathways are carried out by Rhodococcus strains. In turn, strains belonging to Pseudomonas and Bordetella are the main responsible of three of the benzoate to TCA pathways while the benzoate conversion into TCA cycle intermediates via benzoyl-CoA and the catechol meta-cleavage pathways are carried out by beta proteobacteria belonging to genera such as Achromobacter and Variovorax. We have isolated a Rhodococcus strain WAY2 from the consortium which contains the genes encoding the three biphenyl to benzoate pathways indicating that this strain is responsible for all the biphenyl to benzoate transformations. The presented results show that metagenomic analysis of consortia allows the identification of bacteria active in biodegradation processes and the assignment of specific reactions and pathways to specific bacterial groups.Gaudreau, A.M., Labrie, J., Goetz, C., Dufour, S., Jacques, M., 2018. Evaluation of MALDI-TOF mass spectrometry for the identification of bacteria growing as biofilms. Journal of Microbiological Methods 145, 79-81. evaluated MALDI-TOF to identify bacteria from biofilms. We compared three sample preparation procedures on biofilms grown in vitro. The extended direct transfer method was able to identify 13 isolates out of 18 (72%) at the species level and 15 out of 18 (83%) at the genus level.Ge, R., Zhu, W., Wilde, S.A., Wu, H., 2018. Remnants of Eoarchean continental crust derived from a subducted proto-arc. Science Advances 4, Article eaao3159. [3.6 to 4.0 billion years ago (Ga)] tonalite-trondhjemite-granodiorite (TTG) is the major component of Earth’s oldest remnant continental crust, thereby holding the key to understanding how continental crust originated and when plate tectonics started in the early Earth. TTGs are mostly generated by partial melting of hydrated mafic rocks at different depths, but whether this requires subduction remains enigmatic. Recent studies show that most Archean TTGs formed at relatively low pressures (≤1.5 GPa) and do not require subduction. We report a suite of newly discovered Eoarchean tonalitic gneisses dated at ~3.7 Ga from the Tarim Craton, northwestern China. These rocks are probably the oldest high-pressure TTGs so far documented worldwide. Thermodynamic and trace element modeling demonstrates that the parent magma may have been generated by water-fluxed partial melting of moderately enriched arc-like basalts at 1.8 to 1.9 GPa and 800° to 830°C, indicating an apparent geothermal gradient (400° to 450°C GPa?1) typical for hot subduction zones. They also locally record geochemical evidence for magma interaction with a mantle wedge. Accordingly, we propose that these high-pressure TTGs were generated by partial melting of a subducted proto-arc during arc accretion. Our model implies that modern-style plate tectonics was operative, at least locally, at ~3.7 Ga and was responsible for generating some of the oldest continental nuclei.Geilert, S., Hensen, C., Schmidt, M., Liebetrau, V., Scholz, F., Doll, M., Deng, L., Lever, M.A., Su, C.C., Schl?mer, S., Sarkar, S., Thiel, V., Berndt, C., 2018. Transition from hydrothermal vents to cold seeps records timing of carbon release in the Guaymas Basin, Gulf of California. Biogeosciences Discussions 2018, 1-34. Guaymas Basin in the Gulf of California is an ideal site to test the hypothesis that magmatic intrusions into organic-rich sediments can cause the release of large amounts of thermogenic methane and CO2 that may lead to climate warming. In this study pore fluids close (~?500?m) to a hydrothermal vent field and at cold seeps up to 20?km away from the northern rift axis were studied to determine the influence of magmatic intrusions on pore fluid composition and gas migration. Pore fluids close to the hydrothermal vent area show predominantly seawater composition, indicating a shallow circulation system transporting seawater to the hydrothermal catchment area rather than being influenced by hydrothermal fluids themselves. Only in the deeper part of the sediment core, composed of hydrothermal vent debris, Sr isotopes indicate a mixture with hydrothermal fluids of ~?3?%. Also cold seep pore fluids show mainly seawater composition. Most of the methane is of microbial origin and consumed by anaerobic oxidation in shallow sediments, whereas ethane has a clear thermogenic signature. Fluid and gas flow might have been active during sill emplacement in the Guaymas Basin, but ceased 28 to 7 thousand years ago, based on sediment thickness above extinct conduits. Our results indicate that carbon release depends on the longevity of sill-induced, hydrothermal systems which is a currently unconstrained factor.Gheibi, S., Vilarrasa, V., Holt, R.M., 2018. Numerical analysis of mixed-mode rupture propagation of faults in reservoir-caprock system in CO2 storage. International Journal of Greenhouse Gas Control 71, 46-61. seismicity and caprock integrity are among the most important concerns in CO2 storage operations. Understanding and minimizing fault/fracture reactivation in the first place, and rupture growth/propagation beyond its surface afterwards, are fundamental to achieve a successful deployment of geologic carbon storage projects. Rock fracture mechanics provides useful concepts to study the propagation of discontinuities such as pre-existing faults and fractures. In this paper, we aim at developing a methodology to investigate the rupture propagation likelihood of faults/fractures inside a reservoir and its surrounding (including the caprock) as a result of reservoir pressurization. In this methodology, mode I (tensile) and mode II (shear) stress intensity factors of a given fault/fracture are calculated based on Linear Elastic Fracture Mechanics. A fault/fracture can propagate either in mode I, mode II or a combination of both (also called mixed-mode) based on the comparison of the stress intensity factors and fracture toughness. The proposed methodology, which has been embedded into a hybrid Finite Element Method-Discrete Element Method in-house code called MDEM, has the capability to obtain the direction of mode I and mode II rupture in front of a fault/fracture tip. Two coefficients are defined as stress intensity paths (κ) for a fault/fracture, as the change of stress intensity factors for the two failure modes of a given discontinuity per unit pore pressure change of the reservoir after injection. Based on these stress intensity path coefficients, a relationship is given to calculate the threshold pressure buildup above which the two propagation modes may occur. We use the proposed methodology to investigate the rupture growth likelihood of faults in and around a closed reservoir due to its pressurization. Simulation results indicate that mode I failure is likely to occur inside the reservoir for faults with low dip angle in compressional stress regimes. However, the initiated mode I failure may not have the chance to grow upwards because the minimum principal is in the vertical direction and thus, the initiated rupture tends to rotate and grow horizontally. In contrast, mode I rupture is likely to occur in the caprock for faults with high dip angle in extensional stress regimes. The initiated rupture may grow upwards if the newly created fracture becomes hydraulically connected with the reservoir. We find that mode II rupture is not likely to occur in any of the investigated scenarios. Simulation results show that the coefficients of the stress intensity factors depend on the faults location, dipping angle, fault length, presence of other faults, reservoir aspect ratio and reservoir and caprock stiffness.Giorio, C., Kehrwald, N., Barbante, C., Kalberer, M., King, A.C.F., Thomas, E.R., Wolff, E.W., Zennaro, P., 2018. Prospects for reconstructing paleoenvironmental conditions from organic compounds in polar snow and ice. Quaternary Science Reviews 183, 1-22. ice cores provide information about past climate and environmental changes over periods ranging from a few years up to 800,000 years. The majority of chemical studies have focused on determining inorganic components, such as major ions and trace elements as well as on their isotopic fingerprint. In this paper, we review the different classes of organic compounds that might yield environmental information, discussing existing research and what is needed to improve knowledge. We also discuss the problems of sampling, analysis and interpretation of organic molecules in ice. This review highlights the great potential for organic compounds to be used as proxies for anthropogenic activities, past fire events from different types of biomass, terrestrial biogenic emissions and marine biological activity, along with the possibility of inferring past temperature fluctuations and even large-scale climate variability. In parallel, comprehensive research needs to be done to assess the atmospheric stability of these compounds, their ability to be transported long distances in the atmosphere, and their stability in the archive in order to better interpret their fluxes in ice cores. In addition, specific decontamination procedures, analytical methods with low detection limits (ng/L or lower), fast analysis time and low sample requests need to be developed in order to ensure a good time resolution in the archive.Goldman, Y., Linn, R., Shamir, O., Weinstein-Evron, M., 2018. Micro-RTI as a novel technology for the investigation and documentation of archaeological textiles. Journal of Archaeological Science: Reports 19, 1-10. are among the most informative items among archaeological finds. However, their physical and chemical characteristics and the effect of prolonged burial make them particularly sensitive and difficult to investigate and conserve. In keeping with conservation ethics and in order to ensure the preservation of textiles while allowing maximal retrieval of information, advanced research tools are required. Reflectance Transformation Imaging (RTI) is an imaging technique which uses reflected light to record the three-dimensional characteristics of the surface of objects. This study investigated the implementation of Micro-RTI - a novel RTI technology using a microscope - for the examination and documentation of archaeological textiles. The technique allows the capture, examination, documentation and presentation of fine surface details which often cannot be identified by ordinary photography. In this study, an assemblage of textiles of different periods from the Judean Desert, Israel, was examined. Comparison of images made by several techniques in parallel showed that Micro-RTI provides the most comprehensive information about the textiles including a significant advantage in the visual representation of the weave, the fibers, the surface and patterns of decay and erosion. The results of this study demonstrate the significant potential of Micro-RTI technology for the research and documentation of archaeological textiles.Gomes, M.L., 2018. An Archaean oxygen oasis. Nature Geoscience 11, 84-85. first of two stepwise increases in atmospheric oxygen occurred at the end of the Archaean eon. Analyses of sulfur and iron isotopes in pyrite reveal a near-shore environment that hosted locally oxygenated conditions in the Mesoarchaean era.About 2.5 billion years ago, oxygen concentrations in the Earth’s atmosphere rose sharply. This Great Oxidation Event1,2 caused a transition from dominantly anaerobic to aerobic surface ecosystems, and ultimately led to the evolution of complex life on Earth. The agents of change were cyanobacteria, a type of bacteria that evolved the ability to gain energy using water as an electron donor, and release oxygen as a by-product. But it is not clear whether the Great Oxidation Event immediately followed the evolution of oxygenic photosynthesis or was initiated later by another evolutionary innovation or environmental driver. Writing in Nature Geoscience, Eickmann et al.3 present geochemical evidence for the existence of a near-shore marine oxygen oasis about 3 billion years ago, in the Mesoarchaean era. This suggests a delay between the evolution of oxygenic photosynthesis by cyanobacteria and the later widespread oxygenation of the atmosphere (Fig. 1).As the Mesoarchaean (3.2–2.8 billion years ago) falls before the Great Oxidation Event, atmospheric conditions are thought to have been mostly anoxic. Under an anoxic atmosphere, photochemical reactions can fractionate sulfur isotopes independent of mass. Thus, the change from mass-independent sulfur isotopic signatures preserved in older rocks to their absence in rocks younger than 2.45 billion years old is considered to be conclusive proof of the rise of oxygen at the Great Oxidation Event1. However, the mass-independent sulfur signal is muted during the Mesoarchaean, presenting a conundrum. This muted signal could be due to differences in atmospheric photochemistry4 or dilution of the signal by sulfur with a mass-dependent signal. A likely culprit for the latter is the contribution of sulfur with a mass-dependent signal from microbial sulfate reduction. This requires high sulfate levels generated by enhanced oxidative weathering on land under an oxygenated atmosphere. But lack of evidence for mass-dependent fractionations in the Mesoarchaean has previously hampered the interpretation that mass-independent signatures were dampened by inputs from microbial sulfate reduction under elevated atmospheric oxygen and marine sulfate levels.Eickmann and colleagues3 aim to resolve this conundrum. They present sulfur isotope data from pyrites in sediments from South Africa that were deposited 3 billion years ago in a tide-influenced, shallow-marine environment on the Kaapvaal Craton. The data come from two distinct types of pyrites: finely disseminated pyrite from powdered whole-rock samples and pyrite nodules that were sampled by micro-drilling. The finely disseminated pyrites show no conclusive evidence of mass-dependent sulfur isotope fractionation, in line with previous studies. In contrast, sulfur isotope signatures from the pyrite nodules are indicative of mass-dependent sulfur fractionation by microbial sulfate reduction in a sulfate-rich environment. Importantly, both types of pyrite carry mass-independent sulfur isotope signals indicating that they were deposited under a largely anoxic atmosphere. Thus, a localized oxygen oasis must have maintained sufficiently high sulfate levels to impart the mass-dependent sulfur isotope signals in the pyrite nodules.To further explore redox heterogeneity and biogeochemical cycling in this Mesoarchaean shallow-marine environment, Eickmann and colleagues also analyse iron isotopes. They show that the pyrite nodules are depleted in the heavy iron isotope relative to iron that entered the Mesoarchaean deep sea from hydrothermal vents. The hydrothermally sourced iron became progressively depleted during upwelling owing to oxidation and subsequent precipitation, either by microbially mediated reactions or abiotic reactions in the presence of free oxygen. Eickmann et al. hypothesize that the residual iron reaching the near-shore environment was completely oxidized, inheriting the light isotope signal, and was the source of iron for pyrite nodule formation after subsequent reduction in the sediment.The interpretation that the sulfur and iron isotopes indicate locally oxidized conditions relies on the assumption that the pyrite nodules were formed during early diagenesis and thus preserve information about the near-shore environment. The authors present geochemical and textural evidence in support of a primary environmental signal, similar to other Archaean pyrite nodule studies5. Understanding why the nodule pyrites in this study have different sulfur isotope signals from the disseminated pyrites if they formed from dissolution of disseminated pyrite in the sediments during early diagenesis6 may provide additional information about redox heterogeneity in Mesoarchaean oceans.Although Eickmann and colleagues advance our understanding of the muted mass-independent signal in the Mesoarchaean, the oxygen oasis interpretation is, by nature, a localized condition. Thus, a challenge remains to explain how these local conditions might be related to the muted sulfur signature that is found in all the data generated from sediments deposited over approximately 400 million years. Further, after the Mesoarchaean — in the Neoarchaean — the mass-independent sulfur signal should continue to be increasingly diluted as sulfate accumulates in the ocean through oxidative weathering of terrestrial pyrite. But, in fact, the mass-independent signal is stronger in the Neoarchaean4. This could imply that the oxygen levels decreased in the Neoarchaean before the Great Oxidation Event. Alternatively, there may be additional processes, not yet recognized, of sulfur cycling associated with changing atmospheric photochemistry that strengthens the mass-independent signal.The cause of the rapid rise of atmospheric oxygen at the end of the Archaean remains enigmatic. Biological innovations by existing cyanobacteria could have led to an expansion of their oxygenic photosynthetic activity and the accumulation of free oxygen in the atmosphere7. Or environmental changes, such as a global glaciation, could have led to a state change in biogeochemical cycling that tipped the scale towards higher atmospheric oxygen levels8. Either way, these hypotheses need to be tested in the rock record, and Eickmann and colleagues contribute an important piece of evidence that will be used to solve the mystery of the Great Oxidation Event.There are many nuances in the sulfur isotope record of the Archaean. Although not necessarily absolving the cyanobacteria of responsibility, Eickmann and colleagues3 provide further geochemical evidence to suggest that oxygen releasing cyanobacteria were present and active long before the Great Oxidation Event.References1. Farquhar, J. et al. Science 289, 756–758 (2000).2. Bekker, A. et al. Nature 427, 117–120 (2004).3. Eickmann, B. et al. Nat. Geosci., (2018).4. Farquhar, J. et al. Nature 449, 706–709 (2007).5. Marin-Carbonne, J. et al. Earth Planet. Sci. Lett. 392, 67–79 (2014).6. Berner, R. A. Geochim. Cosmochim. Acta 48, 605–615 (1984).7. Schirrmeister, B. E., Gugger, M. & Donoghue, P. C. Palaeontology 58, 769–785 (2015).8. Laakso, T. A. & Schrag, D. P. Geobiology 15, 366–384 (2017).Gonzalez-Martinez, A., Sihvonen, M., Mu?oz-Palazon, B., Rodriguez-Sanchez, A., Mikola, A., Vahala, R., 2018. Microbial ecology of full-scale wastewater treatment systems in the Polar Arctic Circle: Archaea, Bacteria and Fungi. Scientific Reports 8, Article 2208. full-scale biological wastewater treatment systems located in the Polar Arctic Circle region in Finland were investigated to determine their Archaea, Bacteria and Fungi community structure, and their relationship with the operational conditions of the bioreactors by the means of quantitative PCR, massive parallel sequencing and multivariate redundancy analysis. The results showed dominance of Archaea and Bacteria members in the bioreactors. The activated sludge systems showed strong selection of Bacteria but not for Archaea and Fungi, as suggested by diversity analyses. Core OTUs in influent and bioreactors were classified as Methanobrevibacter, Methanosarcina, Terrestrial Group Thaumarchaeota and unclassified Euryarchaeota member for Archaea; Trichococcus, Leptotrichiaceae and Comamonadaceae family, and Methylorosula for Bacteria and Trichosporonaceae family for Fungi. All influents shared core OTUs in all domains, but in bioreactors this did not occur for Bacteria. Oligotype structure of core OTUs showed several ubiquitous Fungi oligotypes as dominant in sewage and bioreactors. Multivariate redundancy analyses showed that the majority of core OTUs were related to organic matter and nutrients removal. Also, there was evidence of competition among Archaea and Fungi core OTUs, while all Bacteria OTUs were positively correlated among them. The results obtained highlighted interesting features of extremely cold temperature bioreactors.Gonzalez-Pimentel, J.L., Miller, A.Z., Jurado, V., Laiz, L., Pereira, M.F.C., Saiz-Jimenez, C., 2018. Yellow coloured mats from lava tubes of La Palma (Canary Islands, Spain) are dominated by metabolically active Actinobacteria. Scientific Reports 8, Article 1944. diversity in lava tubes from Canary Islands (Spain) has never been explored thus far offering a unique opportunity to study subsurface microbiology. Abundant yellow coloured mats developing on coralloid speleothems in a lava tube from La Palma Islands were studied by next-generation sequencing and DNA/RNA clone library analyses for investigating both total and metabolically active bacteria. In addition, morphological and mineralogical characterization was performed by field emission scanning electron microscopy (FESEM), micro-computed tomography, X-ray diffraction and infrared spectroscopy to contextualize sequence data. This approach showed that the coralloid speleothems consist of banded siliceous stalactites composed of opal-A and hydrated halloysite. Analytical pyrolysis was also conducted to infer the possible origin of cave wall pigmentation, revealing that lignin degradation compounds can contribute to speleothem colour. Our RNA-based study showed for the first time that members of the phylum Actinobacteria, with 55% of the clones belonging to Euzebyales order, were metabolically active components of yellow mats. In contrast, the DNA clone library revealed that around 45% of clones were affiliated to Proteobacteria. Composition of microbial phyla obtained by NGS reinforced the DNA clone library data at the phylum level, in which Proteobacteria was the most abundant phylum followed by Actinobacteria.Goodwin, P., Katavouta, A., Roussenov, V.M., Foster, G.L., Rohling, E.J., Williams, R.G., 2018. Pathways to 1.5 °C and 2 °C warming based on observational and geological constraints. Nature Geoscience 11, 102-107. restrict global warming to below the agreed targets requires limiting carbon emissions, the principal driver of anthropogenic warming. However, there is significant uncertainty in projecting the amount of carbon that can be emitted, in part due to the limited number of Earth system model simulations and their discrepancies with present-day observations. Here we demonstrate a novel approach to reduce the uncertainty of climate projections; using theory and geological evidence we generate a very large ensemble (3?×?104) of projections that closely match records for nine key climate metrics, which include warming and ocean heat content. Our analysis narrows the uncertainty in surface-warming projections and reduces the range in equilibrium climate sensitivity. We find that a warming target of 1.5?°C above the pre-industrial level requires the total emitted carbon from the start of year 2017 to be less than 195–205?PgC (in over 66% of the simulations), whereas a warming target of 2?°C is only likely if the emitted carbon remains less than 395–455?PgC. At the current emission rates, these warming targets are reached in 17–18 years and 35–41 years, respectively, so that there is a limited window to develop a more carbon-efficient future.Goswami, V., Hannah, J.L., Stein, H.J., 2018. Why terrestrial coals cannot be dated using the Re-Os geochronometer: Evidence from the Finnmark Platform, southern Barents Sea and the Fire Clay coal horizon, Central Appalachian Basin. International Journal of Coal Geology 188, 121-135. horizons in terrestrial sedimentary sections are key to understanding the structural and thermal evolution of sedimentary basins. Precise and accurate age information for coal horizons can define correlations and the temporal evolution of sedimentary successions. While the biostratigraphy for coal horizons yields relative ages, tied to radiometric ages through the continuously refined geological time scale, direct radiometric ages of coal horizons have been derived only from tonsteins, lithified ash beds. The Re-Os geochronometer has been proven to record accurate and precise depositional ages for sedimentary rocks rich in organic matter. However, the reliability of the Re-Os geochronometer has not yet been assessed for coals deposited in strictly terrestrial environments. Here, in order to test the Re-Os geochronometer, we measure the Re, Os concentrations and isotopic composition of terrestrial coals from two distinct environments: the Finnmark Platform, southern Barents Sea and the Central Appalachian Basin (CAB). Samples from the Finnmark platform (Soldogg Formation) also include an adjacent organic-rich shale horizon. The shale and two coal horizons were also analysed for total organic carbon (TOC) and Rock-Eval data. Results show that the Soldogg coals and shale reached the oil generation widow (Tmax?=?448?±?2?°C), with Type III or mixed Type II/III organic matter, supporting the model for deposition in overbank deposits in a fluvial setting. In contrast, the Fire Clay coals in the CAB were deposited in a broad expanse of mires. Average Re (0.5?±?0.4?ng/g) and Os (23?±?26?pg/g) concentrations of terrestrial Soldogg and Fire Clay coals are similar to those of terrestrial Maghara coal and a few orders of magnitude lower than the marine-influenced Matewan coal. Elevated Re/Os* ratio (Os*?=?Common Os; Os corrected for ingrowth of 187Os since deposition of the sample) for the Fire Clay coals suggests highly reducing and/or euxinic conditions prevailing in the water column of the extensive Carboniferous peat-forming mire in which these coals were deposited. In contrast, lower Re/Os* for Soldogg coals highlight less reducing conditions, likely in a short-lived mire in a dynamic braided stream system. Re and Os* concentrations of terrestrial coals are on the order of Re and Os of plant materials and river sediments, suggesting that debris from plant materials and weathered continental crust are significant contributors of Re and Os to terrestrial coals, with some contribution from water column of the coal mire.This study is the first attempt to apply the Re-Os geochronometer on terrestrial coals. In case of the Soldogg coals and shale, the 187Re/188Os vs. 187Os/188Os relationship displays scatter with no discernible linear trend. The scatter is ascribed to heterogeneity in the initial 187Os/188Os ratios (Osi) and lack of post-depositional isotopic equilibration during subsequent diagenesis. For the Fire Clay coals, 187Os/188Os and 187Re/188Os are well correlated; linear regression of the data, however, does not yield a geologically reasonable age. Rather, the linear relationship results from binary mixing between two end-members: The Fire Clay coal and tonstein, suggesting that Re-Os systematics of terrestrial coals depositing very close to tonstein beds can be significantly disturbed. We conclude that the post-depositional equilibration with a large Re-Os reservoir, as with a marine incursion, is necessary to record a meaningful Re-Os radiometric age for the coals.Gottschall, T., Meyer, T., Schmitt, M., Popp, J., Limpert, J., Tünnermann, A., 2018. Advances in laser concepts for multiplex, coherent Raman scattering micro-spectroscopy and imaging. TrAC Trends in Analytical Chemistry 102, 103-109. this contribution, we want to review recent advances and innovations in laser sources and detection concepts for coherent Raman scattering microscopy with special emphasis on hyperspectral and multiplex imaging methods for biomedical applications. Groundbreaking advances have been made to increase the chemical sensitivity while maintaining video-rate imaging speeds. Excitation and detection schemes have been further improved to enhance the image contrast as well as to increase the spectral coverage and speed of multi-spectral data acquisition along with the ongoing quest to develop both compact and robust but also powerful and rapidly tunable laser sources suitable for integration into biomedical equipment.Graf, J., Tabor, N.J., Ferguson, K., Winkler, D.A., Lee, Y.-N., May, S., Jacobs, L.L., 2018. Diagenesis of dinosaur eggshell from the Gobi Desert, Mongolia. Palaeogeography, Palaeoclimatology, Palaeoecology 494, 65-74. order to test for paleoenvironmental and paleoecological parameters important in dinosaur evolution, thirty-four fragments of dinosaur eggshell, paleosol carbonates from six localities, and calcite crystals from inside a dinosaur femur were collected from the Campanian to Maastrichtian Baruungoyot and Nemegt formations, Gobi Desert, Mongolia. The samples were examined for diagenesis using light microscopy, SEM, and cathodoluminescence, and each was analyzed for δ13C and δ18O values. Eggshell isotope values plot along two trends of enrichment, with paleosol carbonate nodule values plotting along locality specific trends. Convergence of the trends suggests similar initial conditions among localities. Permian-age detrital zircons in the fossiliferous sediment suggest that enriched eggshell and paleosol carbonate nodule δ13C values may have been caused by phreatic zone diagenetic alteration by waters with an aqueous bicarbonate component derived from interaction and dissolution of Permian calcareous marine host rocks. Our hypothetical model for eggshell diagenesis assumes a stable carbon- and oxygen-isotope domain space delimited by three end members: (1) apparently unaltered eggshell with primary microstructure, (2) non-luminescent eggshell with no preserved microstructure, and (3) luminescent eggshell with no preserved microstructure. The two end members showing no preservation of microstructure indicate different phases of diagenetic alteration in the presence of vadose and phreatic waters. None of the samples analyzed can be shown to be sufficiently unaltered for analysis using standard techniques. Biologically, eggshell is porous to facilitate the movement of gases while an embryo is developing within the egg. Geologically, that same property allows the flow of diagenetic ground waters, which modifies the primary isotopic signature of eggshell.Grieve, P.L., Hynek, S.A., Heilweil, V., Sowers, T., Llewellyn, G., Yoxtheimer, D., Solomon, D.K., Brantley, S.L., 2018. Using environmental tracers and modelling to identify natural and gas well-induced emissions of methane into streams. Applied Geochemistry 91, 107-121. of shale gas wells sometimes results in migration of methane (CH4) from boreholes into aquifers. Identification of leakage has relied on analysis of CH4 in individual groundwater samples, usually from water wells; however, collection of point data is expensive and prone to artefacts. Methane analysis in streams is a novel way to find potential leakage of CH4 to groundwater. Here, dissolved hydrocarbons and geochemical tracers were measured in streams during base flow in watersheds with high densities of shale gas wells in Pennsylvania (PA) to identify characteristics related to leaking gas wells. Three streams with no known contamination from gas wells and one stream near a gas well previously reported to be leaking CH4 were investigated. The characteristics observed in the stream near the putatively leaking gas well that distinguish it from the streams without leaks include higher CH4 concentrations in riparian groundwater (as high as 4600 versus 206?μg/L), a relatively high gas influx to the stream channel (>70 versus <10?mg?m?2 d?1), hydrocarbon isotopic signatures and radiogenic strontium consistent with Middle Devonian Marcellus Formation shale, and higher concentrations of modern atmospheric age tracers in groundwater. These tracer concentrations may indicate upward transport of hydrocarbons as a separate gas phase rather than in solution. In addition, the stream near the putatively leaking well was not located along a fault-related topographic lineament whereas streams with substantial natural thermogenic CH4 influxes tend to be aligned with potential geologic structures. The stream approach is an efficient technique to estimate watershed-scale groundwater compositions and fluxes of CH4 that reveal natural and anthropogenic sources of methane emissions.Grinham, A., Dunbabin, M., Albert, S., 2018. Importance of sediment organic matter to methane ebullition in a sub-tropical freshwater reservoir. Science of The Total Environment 621, 1199-1207., C., Klemm, D., Haberger, M., Bathke, A., Wegele, H., Bell, C., Kopf, R., 2018. Fast and automated characterization of antibody variants with 4D HPLC/MS. Analytical Chemistry 90, 2119-2125. of unknown monoclonal antibody (mAb) variants is important in order to identify their potential impact on safety, potency, and stability. Ion exchange chromatography (IEC) coupled with UV detection is frequently used to separate and quantify mAb variants in routine quality control (QC). However, characterization of the chromatographic peaks resulting from an IEC separation is an extremely time-consuming process, involving many cumbersome steps. Presented here is an online four-dimensional high performance liquid chromatography–mass spectrometry (4D HPLC/MS) approach, developed to circumvent these limitations. To achieve this, a 2D HPLC system was extended through the introduction of additional modules, hence enabling fully automated bioseparation of mAbs, fractionation of peaks, reduction, tryptic digestion, and reversed-phase (RP) separation of resulting peptides followed by MS detection. The entire separation and analytical process for an unknown peak is performed in less than 1.5 h, leading to a significant time savings, with comparable sequence coverage. To show the comparability with the traditional offline process, a proof of concept study with a previously characterized mAb1 is presented in this paper.Guan, J.-a., Liang, D., 2018. Discussion on the rapid formation mechanism and evolution process of methane hydrate-bearing sediments in Shenhu Area of northern South China Sea. Marine and Petroleum Geology 91, 225-235. of free gas migration in sediment pores, the Shenhu seafloor layers in the northern South China Sea is speculated to have experienced some rapid methane hydrate generation and accumulation. In this study, the main hydrate formation is presumed to occur rapidly in the gas-hydrate-liquid three-phase zone. A first-order reaction kinetics mechanism, which controls the hydrate generation, has been coupled into a flow-transportation-reaction model. The methane flux is chosen to be 0.5?mol·m-2·a?1, and the scope of the kinetic reaction coefficient ranges from 10?1?mol·m-3·MPa?1·a?1 to 102?mol·m-3·MPa?1·a?1. Using these basic conditions, two geological scenarios are designed to investigate the hydrate formation within local effective MH distribution area which is 240-150 mbsf. At three moments (800 a, 4 ka and 8 ka) the state of dissolved methane and salt, layer temperature, gas and hydrate saturation, stratum permeability and capillary pressure has been displayed. The effect of kinetic coefficient on gas and hydrate content, and local temperature, has been compared. The phenomenon accompanying transient decomposition at the hydrate formation front has been found in this process. At last, the constant bottom boundary temperature is set to reflect the influence from deep tectonic activity, and the effects have been discussed. The results demonstrate the possibility of a kind of rapid dynamic evolution process and mechanism on hydrate-bearing sediment formation and aggregation. They also present interesting differences between the enclosing and open characteristics of the Shenhu hydrate system.Gubernat, M., Fraczek-Szczypta, A., Tomala, J., Blazewicz, S., 2018. Catalytic effect of montmorillonite nanoparticles on thermal decomposition of coal tar pitch to carbon. Journal of Analytical and Applied Pyrolysis 130, 90-98. work studies the structure of two types of coal tar pitches (CTPs) modified with montmorillonite (MMT) in the form of nanopowder after annealing to 1000 and 2000?°C. The CTPs differed in polycyclic aromatic hydrocarbons (PAH) content and coking value (CV). The study of scanning electron microscope (SEM), transmission electron microscope (TEM) and x-ray diffraction (XRD) showed that the heat treatment of PAH-containing pitches modified with the ceramic filler to 1000?°C is a way to obtain a new clay-carbon nanocomposite, composed of turbostratic carbon, graphitic carbon, carbon nanotubes (CNT) and MMT. MMT act as a catalyst for carbon nanotubes growth via the gas phase at 1000?°C. Carbon nanotubes growth in pitch-derived carbon material occurred as a result of the presence of hydrocarbon compounds containing PAH evolved during thermal conversion to the carbon phase. Catalytic growth of carbon nanotubes from aromatic hydrocarbons-containing gaseous phase allows to reduce PAH emission during pitch-derived carbon thermal processing.The montmorillonite – modified carbon samples contained a graphitic phase built of preferred orientation crystallites. This phase consisted of well-ordered crystallites with the c-axis spacing, d002?=?0.335?nm. The process occurred due to catalytic graphitization at 1000?°C in the presence of montmorillonite.Guedes, R.E., Luna, A.S., Torres, A.R., 2018. Operating parameters for bio-oil production in biomass pyrolysis: A review. Journal of Analytical and Applied Pyrolysis 129, 134-149. use of renewable energy sources is becoming increasingly necessary. Biomass is considered to have potential to be used as an alternative energy source. The bio-oil obtained of biomass pyrolysis is used as fuels and chemicals products. The yield and composition of pyrolysis oil depend on biomass composition and operating parameters of the process. This review was written with a focus on parameters that influence the process, such as temperature, reaction time, heating rate, gas flow rate, feed rate, particle size and biomass composition and discusses the effect of these parameters on the yield and quality of bio-oil. Besides that, a database with different types of biomass analyzed under different operating conditions that interfere with the pyrolysis process was obtained from 206 research on the pyrolysis process found in the literature. This database can be used for a better understanding of how the composition of the biomass and the parameters of the pyrolysis process interfere with the composition and yield of the obtained products.Guo, H., He, R., Jia, W., Peng, P.a., Lei, Y., Luo, X., Wang, X., Zhang, L., Jiang, C., 2018. Pore characteristics of lacustrine shale within the oil window in the Upper Triassic Yanchang Formation, southeastern Ordos Basin, China. Marine and Petroleum Geology 91, 279-296. matter (OM)-rich shale in the Yanchang Formation is recognized as a promising hybrid shale oil/shale gas system in lacustrine strata in China. Being mainly in the oil window, both the type and distribution of the pores in the shale have been affected by several factors, including petroleum expulsion and retention, mineral and organic composition, and compaction. To obtain a better understanding of the factors controlling OM pore development, 10 core samples were selected with various OM content from the Chang 7 and Chang 9 members of the Yanchang Formation for pore characterization. The investigation combined microscopic observation, both of thin sections and ion milled surfaces of samples with low-pressure carbon dioxide and nitrogen adsorption and bulk porosity measurements, with the main emphasis being on OM-associated pores.The selected samples generally have relatively low total porosity, with the pores being poorly connected. Most pore types found in marine shales were present. The size of porous OM is usually small, mostly measuring several hundreds of nanometers to a few micrometers, which suggest a general compaction effect on pore development. The pore development is related to different petroleum expulsion processes. Shale with very porous OM was a very important feature. The OM coexisting with fluorescent lipitinites was present in a cross-linked nanofiber structure, possibly related to altered extracellular polymeric substances (EPS) by compaction and maturation. Various OM types that varied in both size and shape did not contain any visible pores (e.g. woody relics, migrated solid bitumen and OM laminae in close association with clay minerals). Unusually low meso- and macropore volume in the sample with the highest total organic carbon (TOC) content was confirmed by the predominance of OM laminae without visible pores; however, abundant micropores were indicated by CO2 adsorption analysis. Meso- and macropores in this sample had probably not developed due to a significant compaction effect. Due to the small numbers of studied samples, these OM pore characteristics need to be viewed with caution.Gupta, N., Fathi, E., Belyadi, F., 2018. Effects of nano-pore wall confinements on rarefied gas dynamics in organic rich shale reservoirs. Fuel 220, 120-129. advancements in horizontal well drilling and multistage hydraulic fracturing technology enabled us to unfold major sources of hydrocarbon trapped in ultra-tight formations such as organic rich shales. Tremendous gas production from these reservoirs has transformed today’s energy landscape [1]. Even though multi-stage hydraulic fracturing stimulation provides high permeability paths to transfer gas to the wellbore, however, most of the gas is stored in nano-organic pores of the ultra-low permeability shale matrix that needs to be transferred to the hydraulic fractures to be able to be produced. Studies using advanced imaging technologies such as FIB/SEM and low temperature adsorption measurements show that in the organic rich shale gas reservoirs, Kerogen, the finely dispersed organic nano-porous material with an average pore size of less than 10?nm holds bulk of the total gas in place (GIP). The molecular level interactions between fluid–fluid and fluid–solid organic pore walls govern the transport and storage in these organic nano-pores.To understand the high gas production rates from these ultra-tight formations, the objective of this study is to advance our understanding of non-ideal gas dynamics in multiscale pore structure of organic rich shale matrix (i.e., gas storage and transport influenced by adsorption and adsorbed gas transport) and develop a model to quantify these effects under wide range of reservoir conditions. Among different methods used to model gas dynamics in organic nano-pores such as the multi-continuum, molecular dynamics and Monte Carlo, the lattice Boltzmann method (LBM) is more effective method with much less computational cost relative to other techniques. In this study we focus on rarefied gas dynamics in Kerogen organic nano-tubes under wide range of reservoir pressure and temperature conditions using a two dimensional LBM model.In this model the Langmuir-slip boundary condition at capillary walls, convection or darcy flow and diffusive transport (slippage of free gas molecules and surface transport of adsorbed molecules combined) are considered to model gas transport. Different transport mechanisms and their contribution in gas transport is investigated in a large range of Knudsen numbers from continuum flow to transition flow regime under different reservoir conditions. The deviation from classical theory of fluid flow in micro channels such as Knudsen’s minimum in the mass flow rate is investigated and the effect of gas slippage and double slippage on Knudsen minimum is discussed in details. Finally the results are compared with analytical, and semi analytical solutions available in the literature.The LBM model results displays a clear indication that the gas transport in the capillary tube is highly depends on the pore width size, pressure and temperature. The relative impact of pore size, pressure and temperature on maximum gas velocity and gas wall velocity differs at different flow regime conditions. A critical Knudsen number exists at different reservoir conditions, where the anticipated parabolic fluid velocity profile in organic nano-pores alters and shows higher flow rate as capillary widths reduces due to the underlying effect of molecular phenomena of double slippage and the wall confinement. The comparison with traditional continuum Hagen-Poiseuille law, Klinkenberg slip theory, and recent modified versions of Klinkenberg slip flow equations show that the previous models are valid only in the continuum flow regime, however, they fail to capture high gas flow rates at high Knudsen number and transition flow regimes which is the case in most of the shale organic nano-pore conditions [2].This work is not only important for the advancement of shale gas flow simulators, but also for organic rich shale characterization.Hakimi, M.H., Najaf, A.A., Abdula, R.A., Mohialdeen, I.M.J., 2018. Generation and expulsion history of oil-source rock (Middle Jurassic Sargelu Formation) in the Kurdistan of north Iraq, Zagros folded belt: Implications from 1D basin modeling study. Journal of Petroleum Science and Engineering 162, 852-872. Jurassic Sargelu Formation is an important oil-source rock in the Iraqi Kurdistan oilfields, northern Zagros Fold Belt. The Sargelu source rock is characterised by high organic matter and sulphur content with Type II-S kerogen, which can be expected to generate oil at low maturity stages.A 1D basin modelling was performed by integrating geological and geochemical data of the Sargelu source rock from six wells in the Kurdistan region, north Iraq. The basin modelling results was used to reconstruct the burial and thermal history and to simulate and predict the timing of petroleum generation and expulsion for the Middle Jurassic Sargelu source rock. Burial/thermal history models indicate that the Sargelu source rock had passed the peak-oil generation window during the Late Eocene to Late Miocene. Onset of oil-generation began during the Middle Eocene - Late Miocene (51-11 Ma), whereas the maximum rates of oil with limited gas were generated during the Late Eocene to Late Miocene (52-10 Ma). The models also show that the oil was expelled from the Sargelu source rock since Late Eocene to present-day (44-0 Ma), with transformation ratio higher than 50%. The subsequent high transformation ratio higher than 80% suggests that the generated oil was cracked to gas during the Early Oligocene and continued to present day. These basin modeling results also suggest that the Sargelu Formation acts as an effective oil-source where significant amount of petroleum is expected to be generated and expelled to any nearby prospect reservoir rocks in the Kurdistan region.Hale, O.J., Cramer, R., 2018. Collision-induced dissociation of doubly-charged barium-cationized lipids generated from liquid samples by atmospheric pressure matrix-assisted laser desorption/ionization provides structurally diagnostic product ions. Analytical and Bioanalytical Chemistry 410, 1435-1444. structural information for lipids such as phosphatidylcholines, in particular the location of double bonds in their fatty acid constituents, is an ongoing challenge for mass spectrometry (MS) analysis. Here, we present a novel method utilizing the doping of liquid matrix-assisted laser desorption/ionization (MALDI) samples with divalent metal chloride salts, producing ions with the formula [L+M]2+ (L = lipid, M = divalent metal cation). Multiply charged lipid ions were not detected with the investigated trivalent metal cations. Collision-induced dissociation (CID) product ions from doubly charged metal-cationized lipids include the singly charged intact fatty acids [snx+M–H]+, where ‘x’ represents the position of the fatty acid on the glycerol backbone. The preference of the divalent metal cation to locate on the sn2 fatty acid during CID was found, enabling stereochemical assignment. Pseudo-MS3 experiments such as in-source decay (ISD)-CID and ion mobility-enabled time-aligned parallel (TAP) MS of [snx+M–H]+ provided diagnostic product ion spectra for determining the location of double bonds on the acyl chain and were applied to identify and characterize lipids extracted from soya milk. This novel method is applicable to lipid profiling in the positive ion mode, where structural information of lipids is often difficult to obtain.Hallberg, R.O., Broman, C., 2018. Microbial fossils in the 2.63 Ga Jeerinah Formation, Western Australia—Evidence of microbial oxidation. Geomicrobiology Journal 35, 255-260. diamond drill core from the upper part of the Jeerinah Formation (～2.63 Ga), underlying the Hamersley Group, deposited at a time when the oxygen concentrations in the marine environment were extremely low, was examined for microbial fossils. The paper presents organo-mineral structures in the form of twisted stalks produced by bacteria being present in the laminated black carbonaceous shale sediments. These twisted stalks are organo-mineral structures produced by microaerophilic Fe(II)-oxidizing-type bacteria such as Gallionella and/or Mariprofundus that are active at very low-oxygen concentrations, thus providing evidence for oxygen being present in the marine environment at 2.63 Ga. Halvorson, J., Lenhoff, A.M., Dittmann, M., Stoll, D.R., 2018. Implications of turbulent flow in connecting capillaries used in high performance liquid chromatography. Journal of Chromatography A 1536, 185-194. ongoing movement in HPLC toward the use of small columns packed with small particles for high speed separations results in eluted peaks with very small volumetric variances. Avoiding degradation of separation performance under these conditions requires careful consideration of all sources of extra-column peak dispersion. Recent trends towards decreased diameters of connecting capillaries and increased flow rates for analytical-scale separations can result in Reynolds numbers that exceed 2000. This raises the possibility of a transition from laminar to turbulent flow, thereby resulting in a higher than expected pressure drop across the capillary at a given flow rate. In this study we collected pressure drop data as a function of flow rate under many conditions relevant to modern HPLC. The variables studied included capillary diameter (50–120 μm) and length (100–550 mm), acetonitrile/water composition (0–100%), and temperature (20–80 °C). Most of the work involved stainless steel capillaries, but a subset of experiments involved fused silica. We then used the experimental data to train a model that enables prediction of pressure drops for all of the conditions studied. We find that a single global friction factor profile is sufficient to predict pressure drops as a function of flow rate that are in qualitative agreement with the experimental results. The quantitative accuracy of these predictions is generally quite good, with a mean prediction error of about 2% over the entire range of conditions studied. Predictions for some outlying capillaries are not as good, with errors as high as ?40%. This variability is probably due mainly to capillary-to-capillary variability, especially in the wall roughness, which is difficult to characterize definitively. We believe the model described here will be very useful to practicing chromatographers for predicting the conditions under which turbulent flow might develop in their connecting capillaries, and the magnitude of the pressure drop increase over that expected if flow were exclusively laminar.Han, L., Zhang, Y.-M., Song, J.-J., Fan, M.-J., Yu, Y.-J., Liu, P.-P., Zheng, Q.-X., Chen, Q.-S., Bai, C.-C., Sun, T., She, Y.-B., 2018. Automatic untargeted metabolic profiling analysis coupled with chemometrics for improving metabolite identification quality to enhance geographical origin discrimination capability. Journal of Chromatography A 1541, 12-20. metabolic profiling analysis is employed to screen metabolites for specific purposes, such as geographical origin discrimination. However, the data analysis remains a challenging task. In this work, a new automatic untargeted metabolic profiling analysis coupled with a chemometric strategy was developed to improve the metabolite identification results and to enhance the geographical origin discrimination capability. Automatic untargeted metabolic profiling analysis with chemometrics (AuMPAC) was used to screen the total ion chromatographic (TIC) peaks that showed significant differences among the various geographical regions. Then, a chemometric peak resolution strategy is employed for the screened TIC peaks. The retrieved components were further analyzed using ANOVA, and those that showed significant differences were used to build a geographical origin discrimination model by using two-way encoding partial least squares. To demonstrate its performance, a geographical origin discrimination of flaxseed samples from six geographical regions in China was conducted, and 18 TIC peaks were screened. A total of 19 significant different metabolites were obtained after the peak resolution. The accuracy of the geographical origin discrimination was up to 98%. A comparison of the AuMPAC, AMDIS, and XCMS indicated that AuMPACobtained the best geographical origin discrimination results. In conclusion, AuMPAC provided another method for data analysis.Han, Y., Nambi, I.M., Prabhakar Clement, T., 2018. Environmental impacts of the Chennai oil spill accident – A case study. Science of The Total Environment 626, 795-806., a coastal city in India with a population of over 7 million people, was impacted by a major oil spill on January 28th 2017. The spill occurred when two cargo ships collided about two miles away from the Chennai shoreline. The accident released about 75?metric?tons of heavy fuel oil into the Bay of Bengal. This case study provides field observations and laboratory characterization data for this oil spill accident. Our field observations show that the seawalls and groins, which were installed along the Chennai shoreline to manage coastal erosion problems, played a significant role in controlling the oil deposition patterns. A large amount of oil was trapped within the relatively stagnant zone near the seawall-groin intersection region. The initial cleanup efforts used manual methods to skim the trapped oil and these efforts indeed helped recover large amount of oil. Our laboratory data show that the Chennai oil spill residues have unique fingerprints of hopanes and steranes which can be used to track the spill. Our weathering experiments show that volatilization processes should have played a significant role in degrading the oil during initial hours. The characterization data show that the source oil contained about 503,000?mg/kg of total petroleum hydrocarbons (TPH) and 17,586?mg/kg of total polycyclic aromatic hydrocarbons (PAHs). The field samples collected 6 and 62?days after the spill contained about 71,000 and 28,000?mg/kg of TPH and 4854 and 4016?mg/kg of total PAHs, respectively. The field samples had a relatively large percentage of heavy PAHs, and most of these PAHs are highly toxic compounds that are difficult to weather and their long-term effects on coastal ecosystems are largely unknown. Therefore, more detailed studies are needed to monitor and track the long term environmental impacts of the Chennai oil spill residues on the Bay of Bengal coastal ecosystem.Han, Y., Zhang, Y., Xu, C., Hsu, C.S., 2018. Molecular characterization of sulfur-containing compounds in petroleum. Fuel 221, 144-158. compounds (SCCs) are the most abundant heteroatom compounds in petroleum. The characterization of SCCs in crude oils and petroleum products has great importance not only for the downstream refining process control/optimization and environmental compliance but also for upstream geochemical studies for exploration and production. In recent years, a variety of methods to analyze SCCs have been developed and practiced where chromatography and mass spectrometry have played major roles. This review summarizes the analytical strategy and some of the most important and promising technologies, from sample pretreatment to molecular level characterization. For the convenience of discussions and practical applications, we divide the petroleum mixtures containing sulfur components into gas chromatography (GC)-amenable and nonvolatile fractions. For the former, gas chromatography (GC) and comprehensive two-dimensional gas chromatography (GC?×?GC) utilizing sulfur-selective detectors or mass spectrometry (GC–MS) are predominant analytical techniques. For the latter, molecular characterization is much more difficult and challenging. High performance liquid chromatography (HPLC) or direct liquid infusion and its combination with mass spectrometry (LC–MS), especially ultra-high resolution mass spectrometry, such as Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and Orbitrap MS, associated with various atmospheric ionization techniques are the most practical approaches. Some ionization techniques are underutilized, such as atmospheric pressure chemical ionization (APCI). The use of surface desorption ionization techniques, direct electrospray ionization (DSEI) and desorption atmospheric chemical ionization (DAPCI), for the molecular characterization of insoluble kerogens that has been characterized by X-ray near edge structure spectroscopy (XANES) and X-ray photoelectron spectroscopy (XPS) remain to be explored.Hannah, E.L., McLaughlin, T.R., Keaveney, E.M., Hakenbeck, S.E., 2018. Anglo-Saxon diet in the Conversion period: A comparative isotopic study using carbon and nitrogen. Journal of Archaeological Science: Reports 19, 24-34. Anglo-Saxon England is characterised by great social and religious change. The arrival of missionaries from Rome in 597 CE initiated the gradual process of conversion to Christianity. There is growing evidence for increasing hierarchy and social stratification in the archaeological record at this time, including prominent kingly burials. This paper investigates whether diet was influenced by social stratification and to a lesser extent religion in two seventh-century cemetery populations: Melbourn, Cambridgeshire, and Polhill, Kent. Analysis of carbon and nitrogen stable isotopes from 116 human individuals was undertaken. Factors considered included age, sex, wealth and other notable grave features. Results showed that the diets of both populations were largely unaffected by these wider social processes, with negligible differences between social groups. The results were placed in the context of wider Anglo-Saxon dietary studies and highlight that Anglo-Saxon populations consistently display overwhelmingly similar ranges of carbon and nitrogen isotopes.Hao, Z., Bechtel, H.A., Kneafsey, T., Gilbert, B., Nico, P.S., 2018. Cross-scale molecular analysis of chemical heterogeneity in shale rocks. Scientific Reports 8, Article 2552. organic and mineralogical heterogeneity in shale at micrometer and nanometer spatial scales contributes to the quality of gas reserves, gas flow mechanisms and gas production. Here, we demonstrate two molecular imaging approaches based on infrared spectroscopy to obtain mineral and kerogen information at these mesoscale spatial resolutions in large-sized shale rock samples. The first method is a modified microscopic attenuated total reflectance measurement that utilizes a large germanium hemisphere combined with a focal plane array detector to rapidly capture chemical images of shale rock surfaces spanning hundreds of micrometers with micrometer spatial resolution. The second method, synchrotron infrared nano-spectroscopy, utilizes a metallic atomic force microscope tip to obtain chemical images of micrometer dimensions but with nanometer spatial resolution. This chemically “deconvoluted” imaging at the nano-pore scale is then used to build a machine learning model to generate a molecular distribution map across scales with a spatial span of 1000 times, which enables high-throughput geochemical characterization in greater details across the nano-pore and micro-grain scales and allows us to identify co-localization of mineral phases with chemically distinct organics and even with gas phase sorbents. This characterization is fundamental to understand mineral and organic compositions affecting the behavior of shales.Harris, R.A., May, J.C., Stinson, C.A., Xia, Y., McLean, J.A., 2018. Determining double bond position in lipids using online ozonolysis coupled to liquid chromatography and ion mobility-mass spectrometry. Analytical Chemistry 90, 1915-1924. increasing focus on lipid metabolism has revealed a need for analytical techniques capable of structurally characterizing lipids with a high degree of specificity. Lipids can exist as any one of a large number of double bond positional isomers, which are indistinguishable by single-stage mass spectrometry alone. Ozonolysis reactions coupled to mass spectrometry have previously been demonstrated as a means for localizing double bonds in unsaturated lipids. Here we describe an online, solution-phase reactor using ozone produced via a low-pressure mercury lamp, which generates aldehyde products diagnostic of cleavage at a particular double bond position. This flow-cell device is utilized in conjunction with structurally selective ion mobility-mass spectrometry. The lamp-mediated reaction was found to be effective for multiple lipid species in both positive and negative ionization modes, and the conversion efficiency from precursor to product ions was tunable across a wide range (20–95%) by varying the flow rate through the ozonolysis device. Ion mobility separation of the ozonolysis products generated additional structural information and revealed the presence of saturated species in a complex mixture. The method presented here is simple, robust, and readily coupled to existing instrument platforms with minimal modifications necessary. For these reasons, application to standard lipidomic workflows is possible and aids in more comprehensive structural characterization of a myriad of lipid species.Harrison, B.K., Myrbo, A., Flood, B.E., Bailey, J.V., 2018. Abrupt burial imparts persistent changes to the bacterial diversity of turbidite-associated sediment profiles. Geobiology 16, 190-202. emplacement of subaqueous gravity-driven sediment flows imposes a significant physical and geochemical impact on underlying sediment and microbial communities. Although previous studies have established lasting mineralogical and biological signatures of turbidite deposition, the response of bacteria and archaea within and beneath debris flows remains poorly constrained. Both bacterial cells associated with the underlying sediment and those attached to allochthonous material must respond to substantially altered environmental conditions and selective pressures. As a consequence, turbidites and underlying sediments provide an exceptional opportunity to examine (i) the microbial community response to rapid sedimentation and (ii) the preservation and identification of displaced micro-organisms. We collected Illumina MiSeq sequence libraries across turbidite boundaries at ~26 cm sediment depth in La Jolla Canyon off the coast of California, and at ~50 cm depth in meromictic Twin Lake, Hennepin County, MN. 16S rRNA gene signatures of relict and active bacterial populations exhibit persistent differences attributable to turbidite deposition. In particular, both the marine and lacustrine turbidite boundaries are sharply demarcated by the abundance and diversity of Chloroflexi, suggesting a characteristic sensitivity to sediment disturbance history or to differences in organic substrates across turbidite profiles. Variations in the abundance of putative dissimilatory sulfate-reducing Deltaproteobacteria across the buried La Jolla Canyon sediment–water interface reflect turbidite-induced changes to the geochemical environment. Species-level distinctions within the Deltaproteobacteria clearly conform to the sedimentological boundary, suggesting a continuing impact of genetic inheritance distinguishable from broader trends attributable to selective pressure. Abrupt, <1-cm scale changes in bacterial diversity across the Twin Lake turbidite contact are consistent with previous studies showing that relict DNA signatures attributable to sediment transport may be more easily preserved in low-energy, anoxic environments. This work raises the possibility that deep subsurface microbial communities may inherit variations in microbial diversity from sediment flow and deformation events.Hassanshahian, M., Ghoebani, S., 2018. Isolation and characterization of iron and sulfur-oxidizing bacteria from Maiduk copper mine at Shahrbabk Province in Iran. Geomicrobiology Journal 35, 261-265. oxidation of iron and sulfur are important steps in biogeochemical cycles in mining environments. The aim of this study was the enrichment and identification of two important groups of bacteria that are involved in bioleaching of copper ores. Some soil samples were collected from the Maiduk copper mine. Iron-oxidizing bacteria were enriched in 9K medium containing ferrous sulfate, and sulfur oxidizers were enriched in 9K medium containing powdered sulfur instead of ferrous sulfate as energy source. After three subcultures, autotrophic bacteria were isolated on 9K agarose medium with appropriate energy sources. The autotrophic bacteria from the enrichments were identified by amplification of 16S rRNA gene and sequencing. Bioleaching experiments were performed in 100 ml of 9K medium containing 5 g of low-grade copper ore instead of ferrous sulfate. Twelve different iron and sulfur-oxidizing bacteria were isolated from the collected soil samples of Maiduk copper mine. Molecular identification indicated that two prevalent strains in the ore enrichments could be assigned to the Acidithiobacillus ferooxidans strain HGM and the Thiobacillus thioparus strain HGE. These two strains reached their logarithmic phase of growth after 8 days of incubation in their respective media at 30°C. Of these two cultures, strain HGM leached more copper ore (300 ppm) from the Maiduk copper ore than did strain HGE (200 ppm). Application of these two strains to the Maiduk copper ore in situ and to ore heaps should improve the leaching process.Hazra, B., Wood, D.A., Vishal, V., Varma, A.K., Sakha, D., Singh, A.K., 2018. Porosity controls and fractal disposition of organic-rich Permian shales using low-pressure adsorption techniques. Fuel 220, 837-848. pore structure characteristics of the Lower and Upper Permian shales belonging to the Barren Measures and Raniganj Formations, respectively, were investigated using the low-pressure N2 adsorption-desorption experiments. It was found that the kaolinite content of the Barren Measures shales strongly influenced the Brunauer-Emmett-Teller specific surface area (BET SSA). However, it was the Rock-Eval temperature maxima (Tmax) for the Raniganj Formation shales that influenced the BET SSA values. These shales are dominantly mesoporous and display a negative correlation between BET SSA and average pore radius. Nitrogen adsorption-desorption isotherms are of type IIB and type IV, displaying H2, H3, and hybrid H3-H4 hysteresis patterns. A strong positive correlation exists between average pore radius and the difference in volumes of gas adsorbed at the last-two-highest relative pressures measured. Samples with steeper isotherm slopes at the higher relative pressure range were those with the highest average pore radii. Porosity fractal dimension, D2 displayed a positive correlation with BET SSA and Tmax, and a negative correlation with average pore radius. It is thus concluded that shales with the lowest average pore sizes and highest thermal maturities are marked by larger SSA and more complex pore structures. One of the tested samples (CG 1019) with the highest D2 value is associated with the lowest D1 fractal dimension value. That counter intuitive relationship may reflect analytical constraints of the nitrogen adsorption method at lower relative pressures.He, H., Zhen, Y., Mi, T., Fu, L., Yu, Z., 2018. Ammonia-oxidizing archaea and bacteria differentially contribute to ammonia oxidation in sediments from adjacent waters of Rushan Bay, China. Frontiers in Microbiology 9, 116. doi: 10.3389/fmicb.2018.00116. oxidation plays a significant role in the nitrogen cycle in marine sediments. Ammonia-oxidizing archaea (AOA) and bacteria (AOB) are the key contributors to ammonia oxidation, and their relative contribution to this process is one of the most important issues related to the nitrogen cycle in the ocean. In this study, the differential contributions of AOA and AOB to ammonia oxidation in surface sediments from adjacent waters of Rushan Bay were studied based on the ammonia monooxygenase (amoA) gene. Molecular biology techniques were used to analyze ammonia oxidizers’ community characteristics, and potential nitrification incubation was applied to understand the ammonia oxidizers’ community activity. The objective was to determine the community structure and activity of AOA and AOB in surface sediments from adjacent waters of Rushan Bay and to discuss the different contributions of AOA and AOB to ammonia oxidation during summer and winter seasons in the studied area. Pyrosequencing analysis revealed that the diversity of AOA was higher than that of AOB. The majority of AOA and AOB clustered into Nitrosopumilus and Nitrosospira, respectively, indicating that the Nitrosopumilus group and Nitrosospira groups may be more adaptable in studied sediments. The AOA community was closely correlated to temperature, salinity and ammonium concentration, whereas the AOB community showed a stronger correlation with temperature, chlorophyll-a content (chla) and nitrite concentration. qPCR results showed that both the abundance and the transcript abundance of AOA was consistently greater than that of AOB. AOA and AOB differentially contributed to ammonia oxidation in different seasons. AOB occupied the dominant position in mediating ammonia oxidation during summer, while AOA might play a dominant role in ammonia oxidation during winter.He, K., Zhang, S., Mi, J., Zhang, W., 2018. Pyrolysis involving n-hexadecane, water and minerals: Insight into the mechanisms and isotope fractionation for water-hydrocarbon reaction. Journal of Analytical and Applied Pyrolysis 130, 198-208. ascertain the effects of minerals and dissolved salts on gas generation from water-hydrocarbon reaction, a series of pyrolysis of n-C16 with water and different minerals or salt solutions at 330–420?°C and 50?MPa were conducted in a gold-tube pyrolysis apparatus. It was shown that both calcite and montmorillonite exhibited evidently catalytic effects on gas generation in pyrolysis of hydrocarbon involving water at elevated temperature. The evident higher D/H ratios of methane in hydrous pyrolysis using deuterated water demonstrate that water provided H or D for hydrocarbon gas generation in water-hydrocarbon reaction. Meanwhile, the presence of two minerals resulted in the distinct distribution of the isomeric index (i-C4/n-C4) and carbon isotopic compositions for gas products. In addition, there was a negative correlation between gas yields/isomeric index and NaCl/KCl concentrations in hydrous pyrolysis of n-C16. Theoretical calculations based on density functional theory (DFT) and transition states (TS) revealed that the activation energies for reactions between alkenes and H+ or water are much lower than those involving water and other organic compounds. The water-hydrocarbon reaction in this study should mainly occur via ionic mechanism, though free radical reaction between alkyl radicals and water also presented. Moreover, it was demonstrated that ionic and free radical mechanisms dominated the water-hydrocarbon reaction with montmorillonite and calcite, respectively. The effects of dissolved salts on water-hydrocarbon reaction can be interpreted by the evolution of H+ concentration with salt concentration in aqueous solutions at elevated temperature. In addition, the differences in carbon isotope fractionation for methane generation from water-hydrocarbon reaction via free radical and ionic mechanisms were addressed. Hydrogen isotope fractionation for methane during water-hydrocarbon reaction or hydrogenation by water was also elucidated by thermodynamic calculations. Finally, a model for the prediction of hydrogen isotopic ratios of methane after hydrogen transfer equilibrium between water and methane is proposed.Hebert, A.S., Th?ing, C., Riley, N.M., Kwiecien, N.W., Shiskova, E., Huguet, R., Cardasis, H.L., Kuehn, A., Eliuk, S., Zabrouskov, V., Westphall, M.S., McAlister, G.C., Coon, J.J., 2018. Improved precursor characterization for data-dependent mass spectrometry. Analytical Chemistry 90, 2333-2340. ion trap mass spectrometers are capable of collecting up to 60 tandem MS (MS/MS) scans per second, in theory providing acquisition speeds that can sample every eluting peptide precursor presented to the MS system. In practice, however, the precursor sampling capacity enabled by these ultrafast acquisition rates is often underutilized due to a host of reasons (e.g., long injection times and wide analyzer mass ranges). One often overlooked reason for this underutilization is that the instrument exhausts all the peptide features it identifies as suitable for MS/MS fragmentation. Highly abundant features can prevent annotation of lower abundance precursor ions that occupy similar mass-to-charge (m/z) space, which ultimately inhibits the acquisition of an MS/MS event. Here, we present an advanced peak determination (APD) algorithm that uses an iterative approach to annotate densely populated m/z regions to increase the number of peptides sampled during data-dependent LC-MS/MS analyses. The APD algorithm enables nearly full utilization of the sampling capacity of a quadrupole-Orbitrap-linear ion trap MS system, which yields up to a 40% increase in unique peptide identifications from whole cell HeLa lysates (approximately 53?000 in a 90 min LC-MS/MS analysis). The APD algorithm maintains improved peptide and protein identifications across several modes of proteomic data acquisition, including varying gradient lengths, different degrees of prefractionation, peptides derived from multiple proteases, and phosphoproteomic analyses. Additionally, the use of APD increases the number of peptides characterized per protein, providing improved protein quantification. In all, the APD algorithm increases the number of detectable peptide features, which maximizes utilization of the high MS/MS capacities and significantly improves sampling depth and identifications in proteomic experiments.Helmueller, S.C., Poe, D.P., Kaczmarski, K., 2018. Adiabatic packed column supercritical fluid chromatography using a dual-zone still-air column heater. Journal of Chromatography A 1535, 141-153. approach to conducting SFC separations under pseudo-adiabatic condition utilizing a dual-zone column heater is described. The heater allows for efficient separations at low pressures above the critical temperature by imposing a temperature profile along the column wall that closely matches that for isenthalpic expansion of the fluid inside the column. As a result, the efficiency loss associated with the formation of radial temperature gradients in this difficult region can be largely avoided in packed analytical scale columns. For elution of n-octadecylbenzene at 60?°C with 5% methanol modifier and a flow rate of 3?mL/min, a 250?×?4.6-mm column packed with 5-micron Kinetex C18 particles began to lose efficiency (8% decrease in the number of theoretical plates) at outlet pressures below 142?bar in a traditional forced air oven. The corresponding outlet pressure for onset of excess efficiency loss was decreased to 121?bar when the column was operated in a commercial HPLC column heater, and to 104?bar in the new dual-zone heater operated in adiabatic mode, with corresponding increases in the retention factor for n-octadecylbenzene from 2.9 to 6.8 and 14, respectively. This approach allows for increased retention and efficient separations of otherwise weakly retained analytes. Applications are described for rapid SFC separation of an alkylbenzene mixture using a pressure ramp, and isobaric separation of a cannabinoid mixture.Hendrickson, E., Minor, E.C., Schreiner, K., 2018. Microplastic abundance and composition in western Lake Superior as determined via microscopy, Pyr-GC/MS, and FTIR. Environmental Science & Technology 52, 1787-1796. plastic pollution in marine and freshwater systems is an active area of research, there is not yet an in-depth understanding of the distributions, chemical compositions, and fates of plastics in aquatic environments. In this study, the magnitude, distribution, and common polymers of microplastic pollution in surface waters in western Lake Superior are determined. Analytical methodology, including estimates of ambient contamination during sample collection and processing, are described and employed. Microscopy, pyrolysis-gas chromatography/mass spectrometry (Pyr-GC/MS), and Fourier transform infrared spectroscopy (FTIR) were used to quantify and identify microplastic particles. In surface waters, fibers were the most frequently observed morphology, and, based upon PyGC/MS analysis, polyvinyl chloride was the most frequently observed polymer, followed by polypropylene and polyethylene. The most common polymer identified by FTIR was polyethylene. Despite the low human population in Lake Superior’s watershed, microplastic particles (particularly fibers, fragments, and films) were identified in western-lake surface waters at levels comparable to average values reported in studies within Lake Michigan, the North Atlantic Ocean, and the South Pacific Ocean. This study provides insight into the magnitude of microplastic pollution in western Lake Superior, and describes in detail methodology to improve future microplastics studies in aquatic systems.Heuillet, M., Bellvert, F., Cahoreau, E., Letisse, F., Millard, P., Portais, J.-C., 2018. Methodology for the validation of isotopic analyses by mass spectrometry in stable-isotope labeling experiments. Analytical Chemistry 90, 1852-1860. labeling experiments (ILEs) are widely used to investigate the topology and operation of metabolic networks. The quality of isotopic data collected in ILEs is of utmost importance to ensure reliable biological interpretations, but current evaluation approaches are limited due to a lack of suitable reference material and relevant evaluation criteria. In this work, we present a complete methodology to evaluate mass spectrometry (MS) methods used for quantitative isotopic studies of metabolic systems. This methodology, based on a biological sample containing metabolites with controlled labeling patterns, exploits different quality metrics specific to isotopic analyses (accuracy and precision of isotopologue masses, abundances, and mass shifts and isotopic working range). We applied this methodology to evaluate a novel LC-MS method for the analysis of amino acids, which was tested on high resolution (Orbitrap operating in full scan mode) and low resolution (triple quadrupole operating in multiple reaction monitoring mode) mass spectrometers. Results show excellent accuracy and precision over a large working range and revealed matrix-specific as well as mode-specific characteristics. The proposed methodology can identify reliable (and unreliable) isotopic data in an easy and straightforward way and efficiently supports the identification of sources of systematic biases as well as of the main factors that influence the overall accuracy and precision of measurements. This approach is generic and can be used to validate isotopic analyses on different matrices, analytical platforms, labeled elements, or classes of metabolites. It is expected to strengthen the reliability of isotopic measurements and thereby the biological value of ILEs.Hirashima, T., Toyoshima, M., Moriyama, T., Sato, N., 2018. Evolution of the phosphatidylcholine biosynthesis pathways in green algae: Combinatorial diversity of methyltransferases. Journal of Molecular Evolution 86, 68-76. (PC) is one of the most common phospholipids in eukaryotes, although some green algae such as Chlamydomonas reinhardtii are known to lack PC. Recently, we detected PC in four species in the genus Chlamydomonas: C. applanata NIES-2202, C. asymmetrica NIES-2207, C. debaryana NIES-2212, and C. sphaeroides NIES-2242. To reveal the PC biosynthesis pathways in green algae and the evolutionary scenario involved in their diversity, we analyzed the PC biosynthesis genes in these four algae using draft genome sequences. Homology searches suggested that PC in these species is synthesized by phosphoethanolamine-N-methyltransferase (PEAMT) and/or phosphatidylethanolamine-N-methyltransferase (PEMT), both of which are absent in C. reinhardtii. Recombinant PEAMTs from these algae showed methyltransferase activity for phosphoethanolamine but not for monomethyl phosphoethanolamine in vitro, in contrast to land plant PEAMT, which catalyzes the three methylations from phosphoethanolamine to phosphocholine. This suggested an involvement of other methyltransferases in PC biosynthesis. Here, we characterized the putative phospholipid-N-methyltransferase (PLMT) genes of these species by genetic and phylogenetic analysis. Complementation assays using a PC biosynthesis-deficient yeast suggested that the PLMTs of these algae can synthesize PC from phosphatidylethanolamine. These results indicated that the PC biosynthesis pathways in green algae differ from those of land plants, although the enzymes involved are homologous. Phylogenetic analysis suggested that the PEAMTs and PLMTs in these algae were inherited from the common ancestor of green algae. The absence of PC biosynthesis in many Chlamydomonas species is likely a result of parallel losses of PEAMT and PLMT in this genus.Ho, T.A., Wang, Y., Xiong, Y., Criscenti, L.J., 2018. Differential retention and release of CO2 and CH4 in kerogen nanopores: Implications for gas extraction and carbon sequestration. Fuel 220, 1-7. (CH4) and carbon dioxide (CO2), the two major components generated from kerogen maturation, are stored dominantly in nanometer-sized pores in shale matrix as (1) a compressed gas, (2) an adsorbed surface species and/or (3) a species dissolved in pore water (H2O). In addition, supercritical CO2 has been proposed as a fracturing fluid for simultaneous enhanced oil/gas recovery (EOR) and carbon sequestration. A mechanistic understanding of CH4-CO2-H2O interactions in shale nanopores is critical for designing effective operational processes. Using molecular simulations, we show that kerogen preferentially retains CO2 over CH4 and that the majority of CO2 either generated during kerogen maturation or injected in EOR will remain trapped in the kerogen matrix. The trapped CO2 may be released only if the reservoir pressure drops below the supercritical CO2 pressure. When water is present in the kerogen matrix, it may block CH4 release. However, the addition of CO2 may enhance CH4 release because CO2 can diffuse through water and exchange for adsorbed methane in the kerogen nanopores.Hoffmann, D.L., Angelucci, D.E., Villaverde, V., Zapata, J., Zilh?o, J., 2018. Symbolic use of marine shells and mineral pigments by Iberian Neandertals 115,000 years ago. Science Advances 4, Article eaar5255. de los Aviones (southeast Spain) is a site of the Neandertal-associated Middle Paleolithic of Europe. It has yielded ochred and perforated marine shells, red and yellow colorants, and shell containers that feature residues of complex pigmentatious mixtures. Similar finds from the Middle Stone Age of South Africa have been widely accepted as archaeological proxies for symbolic behavior. U-series dating of the flowstone capping the Cueva de los Aviones deposit shows that the symbolic finds made therein are 115,000 to 120,000 years old and predate the earliest known comparable evidence associated with modern humans by 20,000 to 40,000 years. Given our findings, it is possible that the roots of symbolic material culture may be found among the common ancestor of Neandertals and modern humans, more than half-a-million years ago.Hoffmann, D.L., Standish, C.D., García-Diez, M., Pettitt, P.B., Milton, J.A., Zilh?o, J., Alcolea-González, J.J., Cantalejo-Duarte, P., Collado, H., de Balbín, R., Lorblanchet, M., Ramos-Mu?oz, J., Weniger, G.C., Pike, A.W.G., 2018. U-Th dating of carbonate crusts reveals Neandertal origin of Iberian cave art. Science 359, 912-915.: The extent and nature of symbolic behavior among Neandertals are obscure. Although evidence for Neandertal body ornamentation has been proposed, all cave painting has been attributed to modern humans. Here we present dating results for three sites in Spain that show that cave art emerged in Iberia substantially earlier than previously thought. Uranium-thorium (U-Th) dates on carbonate crusts overlying paintings provide minimum ages for a red linear motif in La Pasiega (Cantabria), a hand stencil in Maltravieso (Extremadura), and red-painted speleothems in Ardales (Andalucía). Collectively, these results show that cave art in Iberia is older than 64.8 thousand years (ka). This cave art is the earliest dated so far and predates, by at least 20 ka, the arrival of modern humans in Europe, which implies Neandertal authorship.Editor's summary: Neandertal cave art. It has been suggested that Neandertals, as well as modern humans, may have painted caves. Hoffmann et al. used uranium-thorium dating of carbonate crusts to show that cave paintings from three different sites in Spain must be older than 64,000 years. These paintings are the oldest dated cave paintings in the world. Importantly, they predate the arrival of modern humans in Europe by at least 20,000 years, which suggests that they must be of Neandertal origin. The cave art comprises mainly red and black paintings and includes representations of various animals, linear signs, geometric shapes, hand stencils, and handprints. Thus, Neandertals possessed a much richer symbolic behavior than previously assumed.Hong, J.-K., Jho, E.H., Choi, H.S., Kang, G., 2018. Role of hemoglobin in hemoglobin-based remediation of the crude oil-contaminated soil. Science of The Total Environment 627, 1174-1181. study investigated the changes in the indigenous microbial community structure with hemoglobin (Hb) application to determine the role of Hb in Hb-based remediation of crude oil-contaminated soil. The phylogenetic diversity of the bacterial community showed that the Hb addition selected surfactants-producing species, thereby, promoting TPH degradation. The significant increase in the CO2 generation, which can be related to the increase in the bacterial abundance inferred from the 16S rRNA gene copy number, supports the enhanced TPH degradation with Hb application. The similar residual TPH concentrations in the presence of only hydrogen peroxide (H2O2) and both Hb and H2O2 suggested that the role of Hb as a catalyst was not as significant as the role of Hb as a nutrient. Also, in the presence of H2O2, a greater recovery of the microbial community structure was observed with the double Hb injection than the single Hb injection. Overall, this study shows that the Hb-based remediation strategies via microbial metabolism can be successfully applied to remediate the crude-oil contaminated Kuwaiti soil.Hong, P., Sekine, Y., Sasamori, T., Sugita, S., 2018. Experimental study of heterogeneous organic chemistry induced by far ultraviolet light: Implications for growth of organic aerosols by CH3 addition in the atmospheres of Titan and early Earth. Icarus 307, 25-39. of organic aerosols driven by photochemical reactions has been observed and suggested in CH4-containing atmospheres, including Titan and early Earth. However, the detailed production and growth mechanisms of organic aerosols driven by solar far ultraviolet (FUV) light remain poorly constrained. We conducted laboratory experiments simulating photochemical reactions in a CH4CO2 atmosphere driven by the FUV radiations dominated by the Lyman-α line. In the experiments, we analyzed time variations in thickness and infrared spectra of solid organic film formed on an optical window in a reaction cell. Gas species formed by FUV irradiation were also analyzed and compared with photochemical model calculations. Our experimental results show that the growth rate of the organic film decreases as the CH4/CO2 ratio of reactant gas mixture decreases, and that the decrease becomes very steep for CH4/CO2?<?1. Comparison with photochemical model calculations suggests that polymerizations of gas-phase hydrocarbons, such as polyynes and aromatics, cannot account for the growth rate of the organic film but that the addition reaction of CH3 radicals onto the organic film with the reaction probability around 10?2 can explain the growth rate. At CH4/CO2?<?1, etching by O atom formed by CO2 photolysis would reduce or inhibit the growth of the organic film. Our results suggest that organic aerosols would grow through CH3 addition onto the surface during the precipitation of aerosol particles in the middle atmosphere of Titan and early Earth. On Titan, effective CH3 addition would reduce C2H6 production in the atmosphere. On early Earth, growth of aerosol particles would be less efficient than those on Titan, possibly resulting in small-sized monomers and influencing UV shielding.Hossain, G.S., Nadarajan, S.P., Zhang, L., Ng, T.-K., Foo, J.L., Ling, H., Choi, W.J., Chang, M.W., 2018. Rewriting the metabolic blueprint: Advances in pathway diversification in microorganisms. Frontiers in Microbiology 9, 155. doi: 10.3389/fmicb.2018.00155. organisms have evolved over millions of years to fine tune their metabolism to create efficient pathways for producing metabolites necessary for their survival. Advancement in the field of synthetic biology has enabled the exploitation of these metabolic pathways for the production of desired compounds by creating microbial cell factories through metabolic engineering, thus providing sustainable routes to obtain value-added chemicals. Following the past success in metabolic engineering, there is increasing interest in diversifying natural metabolic pathways to construct non-natural biosynthesis routes, thereby creating possibilities for producing novel valuable compounds that are non-natural or without elucidated biosynthesis pathways. Thus, the range of chemicals that can be produced by biological systems can be expanded to meet the demands of industries for compounds such as plastic precursors and new antibiotics, most of which can only be obtained through chemical synthesis currently. Herein, we review and discuss novel strategies that have been developed to rewrite natural metabolic blueprints in a bid to broaden the chemical repertoire achievable in microorganisms. This review aims to provide insights on recent approaches taken to open new avenues for achieving biochemical production that are beyond currently available inventions.Hou, H., Shao, L., Li, Y., Li, Z., Zhang, W., Wen, H., 2018. The pore structure and fractal characteristics of shales with low thermal maturity from the Yuqia Coalfield, northern Qaidam Basin, northwestern China. Frontiers of Earth Science 12, 148-159. continental shales from the Middle Jurassic Shimengou Formation of the northern Qaidam Basin, northwestern China, have been investigated in recent years because of their shale gas potential. In this study, a total of twenty-two shale samples were collected from the YQ-1 borehole in the Yuqia Coalfield, northern Qaidam Basin. The total organic carbon (TOC) contents, pore structure parameters, and fractal characteristics of the samples were investigated using TOC analysis, low-temperature nitrogen adsorption experiments, and fractal analysis. The results show that the average pore size of the Shimengou shales varied from 8.149 nm to 20.635 nm with a mean value of 10.74 nm, which is considered mesopore-sized. The pores of the shales are mainly inkbottle- and slit-shaped. The sedimentary environment plays an essential role in controlling the TOC contents of the low maturity shales, with the TOC values of shales from deep to semi-deep lake facies (mean: 5.23%) being notably higher than those of the shore-shallow lake facies (mean: 0.65%). The fractal dimensions range from 2.4639 to 2.6857 with a mean of 2.6122, higher than those of marine shales, which indicates that the pore surface was rougher and the pore structure more complex in these continental shales. The fractal dimensions increase with increasing total pore volume and total specific surface area, and with decreasing average pore size. With increasing TOC contents in shales, the fractal dimensions increase first and then decrease, with the highest value occurring at 2% of TOC content, which is in accordance with the trends between the TOC and both total specific surface area and total pore volume. The pore structure complexity and pore surface roughness of these low-maturity shales would be controlled by the combined effects of both sedimentary environments and the TOC contents.Howes, S.C., Koning, R.I., Koster, A.J., 2018. Correlative microscopy for structural microbiology. Current Opinion in Microbiology 43, 132-138. how microbes utilize their environment is aided by visualizing them in their natural context at high resolution. Correlative imaging enables efficient targeting and identification of labelled viral and bacterial components by light microscopy combined with high resolution imaging by electron microscopy. Advances in genetic and bioorthogonal labelling, improved workflows for targeting and image correlation, and large-scale data collection are increasing the applicability of correlative imaging methods. Furthermore, developments in mass spectroscopy and soft X-ray imaging are expanding the correlative imaging modalities available. Investigating the structure and organization of microbes within their host by combined imaging methods provides important insights into mechanisms of infection and disease which cannot be obtained by other techniques.Hu, H., Hao, F., Guo, X., Dai, F., Lu, Y., Ma, Y., 2018. Investigation of methane sorption of overmature Wufeng-Longmaxi shale in the Jiaoshiba area, Eastern Sichuan Basin, China. Marine and Petroleum Geology 91, 251-261. China, shale gas of production capacity 203, 000?m3 per day has been identified in Well JY1 in the upper Ordovician Wufeng formation shale (O3w) and the lower Silurian Longmaxi formation shale (S1l), Jiaoshiba area, Sichuan Basin. However, the adsorbed gas capacity and the relative ratio between free gas and adsorbed gas are unknown in the Jiaoshiba area, and this is important for further shale gas exploration and development. And different adsorption models need to be calibrated very well to praise the sorption capacity. The samples were obtained from the well JY1. Sorption isotherm experiments were performed at a range of pressures (up to 17?MPa) and temperatures (up to 90?°C) to determine the effects of TOC, moisture, and clay minerals on methane adsorption capacity.The methane maxima adsorbed capacity values have a clear positive relationship with TOC. Clay content displays a weak correlation with methane adsorbed amounts normalized to TOC, indicating that clay minerals are a minor contributor to shale adsorption capacity. Moisture reduces methane sorption capacity by around 20%.Both the supercritical Dubinin–Radushkevich (SDR)-based and the Langmuir-based excess adsorption models are used to fit measured adsorption isotherms. Most of the methane adsorption phase density values fitted by both models are greater than the density of liquid phase methane at its boiling points, 424?mg/cm3. For the Langmuir-based model, a fixed adsorption density of 424, or 373?mg/cm3 was used in fitting the experimental data, which will result in higher maximum adsorbed capacity values. For the SDR-based model, maxima adsorbed capacity values remain stable and have nothing to do with sorption phase density.Hu, M., Müller, E., Schymanski, E.L., Ruttkies, C., Schulze, T., Brack, W., Krauss, M., 2018. Performance of combined fragmentation and retention prediction for the identification of organic micropollutants by LC-HRMS. Analytical and Bioanalytical Chemistry 410, 1931-1941. nontarget screening, structure elucidation of small molecules from high resolution mass spectrometry (HRMS) data is challenging, particularly the selection of the most likely candidate structure among the many retrieved from compound databases. Several fragmentation and retention prediction methods have been developed to improve this candidate selection. In order to evaluate their performance, we compared two in silico fragmenters (MetFrag and CFM-ID) and two retention time prediction models (based on the chromatographic hydrophobicity index (CHI) and on log D). A set of 78 known organic micropollutants was analyzed by liquid chromatography coupled to a LTQ Orbitrap HRMS with electrospray ionization (ESI) in positive and negative mode using two fragmentation techniques with different collision energies. Both fragmenters (MetFrag and CFM-ID) performed well for most compounds, with average ranking the correct candidate structure within the top 25% and 22 to 37% for ESI+ and ESI? mode, respectively. The rank of the correct candidate structure slightly improved when MetFrag and CFM-ID were combined. For unknown compounds detected in both ESI+ and ESI?, generally positive mode mass spectra were better for further structure elucidation. Both retention prediction models performed reasonably well for more hydrophobic compounds but not for early eluting hydrophilic substances. The log D prediction showed a better accuracy than the CHI model. Although the two fragmentation prediction methods are more diagnostic and sensitive for candidate selection, the inclusion of retention prediction by calculating a consensus score with optimized weighting can improve the ranking of correct candidates as compared to the individual methods.Hu, T., Pang, X., Jiang, S., Wang, Q., Zheng, X., Ding, X., Zhao, Y., Zhu, C., Li, H., 2018. Oil content evaluation of lacustrine organic-rich shale with strong heterogeneity: A case study of the Middle Permian Lucaogou Formation in Jimusaer Sag, Junggar Basin, NW China. Fuel 221, 196-205. shale oil resources were recently been found in lacustrine organic-rich shale with strong heterogeneity, however, few studies have been conducted to examine their oil contents, resulting in considerable risks in lacustrine shale oil exploration. The Middle Permian Lucaogou Formation (P2l) shale in Jimusaer Sag is a typical lacustrine deposit with strong heterogeneity, and its shale oil resource shows great potential. Integrated geochemical characterization of 265 core samples were conducted and results show that the P2l shale developed in an anoxic lacustrine with stratified salty water and the organic matter in the upper sub-member shale of the P2l is more oil-prone than that in the lower sub-member shale of the P2l. The hydrocarbon generation potential of the P2l shale decreases with the kerogen types changing from Type I to Type III, however, the residual hydrocarbon contents of the P2l shale increases from Type I to II1 kerogen, and then decreases from Type II1 to III kerogen, this is mainly due to differentiated hydrocarbon expulsion efficiencies among different kerogen types. Based on S1 and TOC values and the S1/TOC ratios, considering the oil enrichment degree, this study classified the shale oil resources in the P2l shale into four categories: enriched, moderately enriched, less efficient, and invalid resources. The enriched and moderately enriched resources are mainly shales with Type II1 kerogen, followed by Type II2 kerogen, and the middle interval of the Lower P2l shale is the most favourable target for further shale oil exploration. The improved evaluation criteria are applicable for evaluating shale oil plays with strong heterogeneity qualitatively and quantitatively in terrestrial lacustrine basins in other parts of the world.Hu, Y., Cai, J., Bai, C., Shao, K., Tang, X., Gao, G., 2018. Contrasting patterns of the bacterial and archaeal communities in a high-elevation river in northwestern China. Journal of Microbiology 56, 104-112. patterns of macrobiota in lotic ecosystems have been extensively explored, however, the dynamics of microbiota remain poorly investigated, especially in the high-elevation region. To address this deficit, we collected eight samples to unveil the bacterial and archaeal community in the Kaidu river, located at the arid region of northwestern China (an average of 2,500 m a.s.l.). For the bacterial community, phylogenetically Betaproteobacteria prevailed, followed by Alphaproteobacteria and Actinobacteria; at the finer genus level, Limnohabitans and Variovorax were prominent. Along the river, the bacterial community showed a continuous succession. Specifically, their α- and β-diversity gradually increased, suggesting a distance-decay pattern. Additionally, there was an ecological transition between the dominant and the rare sub-community along the river: the relative abundance of the dominant members gradually decreased as the rare members increased. We report that temperature and spatial distance were significantly related to the variation of bacterial community. Variance partitioning analysis showed that the environmental factors contributed more to the bacterial community than did the spatial distance. In the case of the archaeal community, the methanogenic groups, mainly Methanosaeta and Methanosarcina, were prominent within the Kaidu river. Unlike the continuous change in the patterns of the bacterial community, the archaeal community showed a constant pattern along the river. Our results showed that the archaeal community was independent of the environmental and spatial factors. We propose that the inoculation of soil-derived archaea is responsible for the archaeal community in the Kaidu river. Together, our study demonstrated that the bacterial community in the high-elevation Kaidu river is a continuum, whereas the archaeal community is not.Hu, Z., Kang, S., Yan, F., Zhang, Y., Li, Y., Chen, P., Qin, X., Wang, K., Gao, S., Li, C., 2018. Dissolved organic carbon fractionation accelerates glacier-melting: A case study in the northern Tibetan Plateau. Science of The Total Environment 627, 579-585. glacierized regions, melting process has a significant effect on concentrations and light absorption characteristics of dissolved organic carbon (DOC), potentially resulting in variations of its radiative forcing, which is not yet relevant research at glacier region of the Tibetan Plateau (TP). In this study, DOC fractionation and its radiative forcing change during the melting process were investigated at Laohugou glacier No. 12 (LHG glacier) in western Qilian Mts., northern TP. DOC concentrations in fresh snow, snowpit and surface ice samples were 0.38?±?0.06, 0.22?±?0.11 and 0.60?±?0.21?mg?L?1, respectively. Their mass absorption cross-section at 365?nm (MAC365) were 0.65?±?0.16, 4.71?±?3.68 and 1.44?±?0.52?m2?g?1, respectively. The MAC365 values of snowpit samples showed a significant negative correlation with DOC concentrations, indicating DOC with high MAC365 values were likely to be kept in snow during the melting process. Topsoil samples of LHG glacierized region likely contributed a lot to snowpit DOC with high MAC365 values due to their similar absorption spectra. Spatially, the DOC concentration of surface ice samples increased from terminus to the upper part of the glacier. Correspondingly, the MAC365 value showed decreased trend. In the freezing experiment on surface ice and topsoil samples, small part of DOC with high MAC365 value was also likely to enter first frozen solid phase. In addition, the radiative forcing caused by snowpit and surface ice DOC increased around 7.64?±?2.93 and 4.95?±?1.19 times relative to fresh snow DOC, indicating the snow/ice melting caused by increased light-absorbing DOC needs to be considered in the future research.Huang, X., Zhao, B., Wang, K., Hu, Y., Meyers, P.A., 2018. Seasonal variations of leaf wax n-alkane molecular composition and δD values in two subtropical deciduous tree species: Results from a three-year monitoring program in central China. Organic Geochemistry 118, 15-26. investigated the seasonal variations of the molecular and hydrogen isotopic compositions of leaf cuticular n-alkanes (δDalk) in two subtropical deciduous tree species (Quercus chenii, Liquidambar formosana) over a three-year period. Average chain length values of long chain n-alkanes in both species are lower in young leaves than in mature ones. The δDalk values in both tree species show seasonal fluctuations that can be as large as 78‰ in a single year. The seasonal changes in molecular and isotopic compositions suggest that leaf wax n-alkanes in these subtropical deciduous tree species integrate environmental information over a large portion of the annual growth cycle in response to fluctuations in environmental stresses (e.g. storms, droughts). In addition, the changes reveal that seasonal patterns of δDalk can differ between different deciduous species at the same location and among different years. Spring leaves collected in 2014 had more negative δDalk values than those collected in 2015 and 2016, possibly responding to differences in annual precipitation D/H ratios and associated atmospheric circulation. These preliminary results highlight that extended seasonal monitoring of leaf wax δDalk values can improve their application to reconstructing paleohydrological histories.Huang, Y.-X., Hu, Z., 2018. An integrated electrochemical and biochemical system for sequential reduction of CO2 to methane. Fuel 220, 8-13. CO2 into commodity chemicals including fuels has emerged as a worldwide focus for science and engineering communities. However, the current state of art in CO2 fixation has low energy efficiency with slow kinetics in the process of CO2 reduction. Here, we propose a new “two-step” approach for CO2 reduction to methane. An integrated reduction system (IRS) was demonstrated to combine the advantages of both electrochemical and biological CO2 reduction reactions. A three-chambered electrochemical cell was designed, in which CO2 was first reduced to formate electrochemically with a decent selectivity. The produced formate was separated by electrodialysis, and subsequently consumed by a strain of methanogen, Methanococcus maripaludis. Through this IRS, CO2 was eventually converted into CH4, allowing easy product separation. In a 100-h test, the total electron recovery efficiency of CH4 was around 37%, with an average CH4 production rate of 0.01?mmole?d?1?mL?1. Five volts of voltage was applied to the system, while the cathodic potential slightly decreased from ?1.5?V to ?1.4?V (vs. Ag/AgCl), showing an excellent stability of the electrode. The energy efficiency of CO2 conversion in terms of electricity consumption was calculated to be 16.9?g?per?kW?h. The results show the promise of IRS presented here in CO2 reduction. Since the electrochemical step and the biochemical step proceeds in separated chambers, independent operation and maintenance of either step become possible. Furthermore, the proposed CO2 IRS offers possibilities of producing a variety of chemicals by introducing appropriate microbial communities using formate as a substrate.Huber, E.J., Stroock, A.D., Koch, D.L., 2018. Modeling the dynamics of remobilized CO2 within the geologic subsurface. International Journal of Greenhouse Gas Control 70, 128-145. after CO2 is injected into a brine aquifer, most reservoir-scale fluid dynamic simulations predict large fractions of the original plume will become immobilized via capillary trapping and dispersed throughout the formation. We begin our analysis with a reservoir in this state and consider the effects caused by a depressurization of the domain (e.g. from a nearby production well or newly formed fracture between neighboring reservoirs) and predict the fraction of CO2 that will be remobilized as a result. We then model the dynamics of this remobilized CO2 in two distinct steps: (1) vertical rise within the reservoir, followed by (2) spreading of mobile CO2 into the far-field of the domain and justify this approach from a scaling analysis of the governing equations. We show that a model of relative permeability that takes account of insights from percolation theory near the minimum CO2 saturation leads to much more rapid rise and subsequent radial spreading of remobilized CO2 than a traditional empirical correlation such as the Brooks-Corey model. Furthermore, we find that over a broad range of remobilized CO2 mass fraction and Bond number, the radial extent of the mobile plume does not exceed a factor of 1.8 times the radius of the original immobilized CO2 region.Hudspith, V.A., Hadden, R.M., Bartlett, A.I., Belcher, C.M., 2018. Does fuel type influence the amount of charcoal produced in wildfires? Implications for the fossil record. Palaeontology 61, 159-171. occurrence is extensively used as a tool for understanding wildfires over geological timescales. Yet, the fossil charcoal literature to date rarely considers that fire alone is capable of creating a bias in the abundance and nature of charcoal it creates, before it even becomes incorporated into the fossil record. In this study we have used state-of-the-art calorimetry to experimentally produce charcoal from 20 species that represent a range of surface fuels and growth habits, as a preliminary step towards assessing whether different fuel types (and plant organs) are equally likely to remain as charcoal post-fire. We observe that charcoal production appears to be species specific, and is related to the intrinsic physical and chemical properties of a given fuel. Our observations therefore suggest that some taxa are likely to be overrepresented in fossil charcoal assemblages (i.e. needle-shed conifers, tree ferns) and others poorly represented, or not preserved at all (i.e. broad shoot-shed conifers, weedy angiosperms, shrub angiosperms, some ferns). Our study highlights the complexity of charcoal production in modern fuels and we consider what a bias in charcoal production may mean for our understanding of palaeowildfires.Humphreys, C.M., Minton, N.P., 2018. Advances in metabolic engineering in the microbial production of fuels and chemicals from C1 gas. Current Opinion in Biotechnology 50, 174-181. future sustainable production of chemicals and fuels from non-petrochemical sources, while at the same time reducing greenhouse gas (GHG) emissions, represent two of society's greatest challenges. Microbial chassis able to grow on waste carbon monoxide (CO) and carbon dioxide (CO2) can provide solutions to both. Ranging from the anaerobic acetogens, through the aerobic chemoautotrophs to the photoautotrophic cyanobacteria, they are able to convert C1 gases into a range of chemicals and fuels which may be enhanced and extended through appropriate metabolic engineering. The necessary improvements will be facilitated by the increasingly sophisticated gene tools that are beginning to emerge as part of the Synthetic Biology revolution. These tools, in combination with more accurate metabolic and genome scale models, will enable C1 chassis to deliver their full potential.Humphreys, M.P., Daniels, C.J., Wolf-Gladrow, D.A., Tyrrell, T., Achterberg, E.P., 2018. On the influence of marine biogeochemical processes over CO2 exchange between the atmosphere and ocean. Marine Chemistry 199, 1-11. ocean holds a large reservoir of carbon dioxide (CO2), and mitigates climate change through uptake of anthropogenic CO2. Fluxes of CO2 between the atmosphere and surface ocean are regulated by a number of physical and biogeochemical processes, resulting in a spatiotemporally heterogeneous CO2 distribution. Determining the influence of each individual process is useful for interpreting marine carbonate system observations, and is also necessary to investigate how changes in these drivers could affect air-sea CO2 exchange. Biogeochemical processes exert an influence primarily through modifying seawater dissolved inorganic carbon (CT) and total alkalinity (AT), thus changing the seawater partial pressure of CO2 (psw). Here, we propose a novel conceptual framework through which the size of the CO2 source or sink generated by any biogeochemical process, denoted Φ, can be evaluated. This is based on the ‘isocapnic quotient’ (Q), which defines the trajectory through (AT,CT) phase space for which there is no change in psw. We discuss the limitations and uncertainties inherent in this technique, which are negligible for most practical purposes, and its links with existing, related approaches. We investigate the effect on Φ of spatiotemporal heterogeneity in Q in the present day surface ocean for several key biogeochemical processes. This leads the magnitude of the CO2 source or sink generated by processes that modify AT to vary spatiotemporally. Finally, we consider how the strength of each process as a CO2 source or sink may change in a warmer, higher-CO2 future ocean.Hur, M., Ware, R.L., Park, J., McKenna, A.M., Rodgers, R.P., Nikolau, B.J., Wurtele, E.S., Marshall, A.G., 2018. Statistically significant differences in composition of petroleum crude oils revealed by volcano plots generated from ultrahigh resolution Fourier transform ion cyclotron resonance mass spectra. Energy & Fuels 32, 1206-1212. “volcano” plot provides a visual means for identifying statistically significant differences between two populations. Here, we introduce the volcano plot as a means for simple, visual identification and statistical ranking of compositional differences between petroleum crude oils. Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry yields the relative abundances of ions in each spectrum that contains up to tens of thousands of elemental compositions (CcHhNnOoSs). From that data, a volcano plot may be generated by plotting statistical significance (p-value, obtained from t test) versus log2(relative abundance ratio). The volcano plot data may be color-coded to highlight differences in heteroatom class (NnOoSs), double bond equivalents (DBE = number of rings plus double bonds to carbon), and/or carbon number. The volcano plot may be used either directly or as a “filter” for including only the most statistically significant differences for data entered into more conventional analyses based on DBE vs carbon number, van Krevelen diagram, and Kendrick mass defect plots. In each case, the volcano plot provides statistically significant criteria, rather than visual grouping.Hussain, I., Aleti, G., Naidu, R., Puschenreiter, M., Mahmood, Q., Rahman, M.M., Wang, F., Shaheen, S., Syed, J.H., 2018. Microbe and plant assisted-remediation of organic xenobiotics and its enhancement by genetically modified organisms and recombinant technology: A review. Science of The Total Environment 628–629, 1582–1599. problems such as the deterioration of groundwater quality, soil degradation and various threats to human, animal and ecosystem health are closely related to the presence of high concentrations of organic xenobiotics in the environment. Employing appropriate technologies to remediate contaminated soils is crucial due to the site-specificity of most remediation methods. The limitations of conventional remediation technologies include poor environmental compatibility, high cost of implementation and poor public acceptability. This raises the call to employ biological methods for remediation. Bioremediation and microbe-assisted bioremediation (phytoremediation) offer many ecological and cost-associated benefits. The overall efficiency and performance of bio- and phytoremediation approaches can be enhanced by genetically modified microbes and plants. Moreover, phytoremediation can also be stimulated by suitable plant-microbe partnerships, i.e. plant-endophytic or plant-rhizospheric associations. Synergistic interactions between recombinant bacteria and genetically modified plants can further enhance the restoration of environments impacted by organic pollutants. Nevertheless, releasing genetically modified microbes and plants into the environment does pose potential risks. These can be minimized by adopting environmental biotechnological techniques and guidelines provided by environmental protection agencies and other regulatory frameworks. The current contribution provides a comprehensive overview on enhanced bioremediation and phytoremediation approaches using transgenic plants and microbes. It also sheds light on the mitigation of associated environmental risks.Iguiniz, M., Rouvière, F., Corbel, E., Roques, N., Heinisch, S., 2018. Comprehensive two dimensional liquid chromatography as analytical strategy for pharmaceutical analysis. Journal of Chromatography A 1536, 195-204. on-line two-dimensional liquid chromatography (LCxLC) is expected to generate impressive peak capacities, which makes it a method of choice for the analysis of complex samples such as pharmaceuticals. A comparative study of different sets of chromatographic conditions including stationary phase, pH additive and organic modifier was carried out with two real pharmaceutical samples in order to find out the best analytical conditions for implementation of one or several generic on-line LCxLC separations. Our choice was based on the evaluation of both degree of orthogonality and practical sample peak capacity under linear gradient conditions. The potential of 190 combinations of chromatographic systems was compared. A set of 3 RPLCxRPLC configurations was found to be very attractive for both samples and in good agreement with the findings of a previous study carried out with 17 model compounds, thereby supporting the idea of using generic LCxLC conditions in the pharmaceutical area. The three selected 2D-systems were implemented for the on-line RPLCxRPLC-UV/MS analysis of two pharmaceutical samples. It was shown, for each sample, that these 2D-systems were able to generate an effective peak capacity close to 1000 in less than 50 min. For each sample, baseline separation was obtained for every known compound and furthermore a large number of unknown impurities could also be separated and identified. Finally, in the proposed conditions, the total number of compounds detected was significantly improved from one RPLC separation to one RPLCxRPLC separation. Only a small additional gain was observed by performing a second RPLCxRPLC separation or even a third one.Inaba, S., 2018. Primary formation path of formaldehyde in hydrothermal vents. Origins of Life and Evolution of Biospheres 48, 1-22. is abundant in the universe and one of the fundamental molecules for life. Hydrothermal vents produce a substantial amount of hydrogen molecules by serpentinization and promote reductive reactions of single carbon compounds. The abundance of formaldehyde is expected to be low due to the high Gibbs free energy in hydrothermal vents. We consider two competing formation pathways of formaldehyde: (1) the reduction of CO by H2 and (2) the reduction of HCOOH by H2 to form a methanediol, followed by the dehydration of the methanediol. We performed a number of quantum chemical simulations to examine the formation of formaldehyde in the gas phase as well as in aqueous solution. The energy barrier is significantly reduced by the catalytic effect of water molecules in aqueous solution and becomes lowest when a water cluster consisted of 5 water molecules catalyzes the reduction. The energy barrier to form a methanediol by the reduction of HCOOH is lower by 17.5 kcal/mol than that to form a formaldehyde by the reduction of CO. Considering the low energy barrier to dehydrate methanediol, the primary pathway to form formaldehyde in hydrothermal vents is concluded to be the reduction of HCOOH by H2, followed by the dehydration of methanediol.Inglis, G.N., Naafs, B.D.A., Zheng, Y., McClymont, E.L., Evershed, R.P., Pancost, R.D., 2018. Distributions of geohopanoids in peat: Implications for the use of hopanoid-based proxies in natural archives. Geochimica et Cosmochimica Acta 224, 249-261. are pentacyclic triterpenoids produced by a wide range of bacteria. Within modern settings, hopanoids mostly occur in the biological 17β,21β(H) configuration. However, in some modern peatlands, the C31 hopane is present as the ‘thermally-mature’ 17α,21β(H) stereoisomer. This has traditionally been ascribed to isomerisation at the C-17 position catalysed by the acidic environment. However, recent work has argued that temperature and/or hydrology also exert a control upon hopane isomerisation. Such findings complicate the application of geohopanoids as palaeoenvironmental proxies. However, due to the small number of peats that have been studied, as well as the lack of peatland diversity sampled, the environmental controls regulating geohopanoid isomerisation remain poorly constrained. Here, we undertake a global approach to investigate the occurrence, distribution and diagenesis of geohopanoids within peat, combining previously published and newly generated data (n?=?395) from peatlands with a wide temperature (?1 to 27?°C) and pH (3–8) range. Our results indicate that peats are characterised by a wide range of geohopanoids. However, the C31 hopane and C32 hopanoic acid (and occasionally the C32 hopanol) typically dominate. C32 hopanoic acids occur as αβ- and ββ-stereoisomers, with the ββ-isomer typically dominating. In contrast, C31 hopanes occur predominantly as the αβ-stereoisomer. These two observations collectively suggest that isomerisation is not inherited from an original biological precursor (i.e. biohopanoids). Using geohopanoid ββ/(αβ?+?ββ) indices, we demonstrate that the abundance of αβ-hopanoids is strongly influenced by the acidic environment, and we observe a significant positive correlation between C31 hopane isomerisation and pH (n?=?94, r2?=?0.64, p?<?0.001). Crucially, there is no correlation between C31 hopane isomerisation and temperature. We therefore conclude that within peats, αβ-hopanoids are acid-catalysed diagenetic products and their occurrence at shallow depths indicates that this isomerisation is rapid. This shows that geohopanoid ββ/(αβ?+?ββ) indices can be used to reconstruct pH within modern and ancient peat-forming environments. However, we only recommend using ββ/(αβ?+?ββ) indices to interrogate large amplitude (>1 pH unit) and longer-term (>1?kyr) variation. Overall, our findings demonstrate the potential of geohopanoids to provide unique new insights into understanding depositional environments and interpreting terrestrial organic matter sources in the geological record.Islam, A., Chevalier, S., Sassi, M., 2018. Structural characterization and numerical simulations of flow properties of standard and reservoir carbonate rocks using micro-tomography. Computers & Geosciences 113, 14-22. advances in imaging techniques and computational power, Digital Rock Physics (DRP) is becoming an increasingly popular tool to characterize reservoir samples and determine their internal structure and flow properties. In this work, we present the details for imaging, segmentation, as well as numerical simulation of single-phase flow through a standard homogenous Silurian dolomite core plug sample as well as a heterogeneous sample from a carbonate reservoir. We develop a procedure that integrates experimental results into the segmentation step to calibrate the porosity. We also look into using two different numerical tools for the simulation; namely Avizo Fire Xlab Hydro that solves the Stokes' equations via the finite volume method and Palabos that solves the same equations using the Lattice Boltzmann Method.Representative Elementary Volume (REV) and isotropy studies are conducted on the two samples and we show how DRP can be a useful tool to characterize rock properties that are time consuming and costly to obtain experimentally.Izumi, K., Endo, K., Kemp, D.B., Inui, M., 2018. Oceanic redox conditions through the late Pliensbachian to early Toarcian on the northwestern Panthalassa margin: Insights from pyrite and geochemical data. Palaeogeography, Palaeoclimatology, Palaeoecology 493, 1-10. early Toarcian oceanic anoxic event (T-OAE; ~ 183 Ma) was a significant palaeoenvironmental perturbation associated with marked changes in oceanic redox conditions. However, the precise redox conditions and redox history of various water masses during the T-OAE, especially those from outside the Boreal and Tethyan realms, are unclear. To address this issue, we present pyrite framboid data from an upper Pliensbachian to lower Toarcian succession deposited on the NW Panthalassa margin in a shallow-water setting (Sakuraguchi-dani section, Toyora area, SW Japan). Available data on lithofacies and redox-sensitive trace elements from the same succession suggest that dysoxic bottom-water conditions generally prevailed, with intermittent short-term oxygenation events. Size-distribution analysis of pyrite framboids reveals that framboid size populations from the silty mudstones during the T-OAE were characterized by small mean diameters and standard deviations. This suggests that euxinic conditions at least intermittently occurred during the T-OAE interval. Most likely, this water-column euxinia was associated with the expansion of an oxygen minimum zone linked to increased primary productivity. This interpretation is consistent with a previously reported increase in fluvial discharge and thus nutrient flux caused by a strengthening of the hydrological cycle.Jackson, T.A., 2018. Variations in the properties of extractable “humic matter” and associated kerogen in sediments through geologic time: Their significance for Precambrian biological evolution and paleoecology. Geomicrobiology Journal 35, 334-353. properties and δ13C values of benzene/methanol-extractable “humic matter” and associated kerogen in a large, diverse collection of Precambrian and Phanerozoic sediments from different parts of the world showed complex systematic variations through geologic time, reflecting major developments in the history of Precambrian life, and different kinds of sediment yielded similar patterns of variation. Moreover, certain data differentiate clearly between glacial and nonglacial detrital sediments, or between lacustrine and marine sediments, and some data suggest the occurrence of Precambrian land life. The abundance of aromatic groups and the proportion of aliphatic to aromatic groups in the extracts showed little variation from the early Archean (ca. 3.3 Ga) to the mid-Proterozoic (ca. 1.6-1.3 or 1.3-1.1 Ga), whereupon they increased sharply, peaked ca. 1.1-0.900 Ga, and then plunged to a minimum in the late Proterozoic (ca. 0.800 Ga) or early Phanerozoic. This is interpreted as indicating that cyanobacteria were the dominant photoautotrophs until the mid-Proterozoic, when algae evolved, proliferating until the late Proterozoic, whereupon their populations were depleted by herbivorous metazoans. Nitrogenous aromatic material increased to a maximum ca. 3.4–3.3 Ga and then decreased steadily to ca. 1.3 Ga, suggesting that early Precambrian cyanobacteria were enriched in photoprotective as well as photosynthetic tetrapyrrole pigments owing to the lack of ultraviolet radiation-shielding atmospheric O2 and O3. The concentration increased again starting ca. 1.3–0.800 Ga, reflecting the rise of algae, peaked ca. 0.680 Ga, and dropped catastrophically to a much lower value in the Cambrian (ca. 0.510 Ga), suggesting mass mortality at the Precambrian-Cambrian boundary.Jansson, J.K., Hofmockel, K.S., 2018. The soil microbiome — from metagenomics to metaphenomics. Current Opinion in Microbiology 43, 162-168. microorganisms carry out important processes, including support of plant growth and cycling of carbon and other nutrients. However, the majority of soil microbes have not yet been isolated and their functions are largely unknown. Although metagenomic sequencing reveals microbial identities and functional gene information, it includes DNA from microbes with vastly varying physiological states. Therefore, metagenomics is only predictive of community functional potential. We posit that the next frontier lies in understanding the metaphenome, the product of the combined genetic potential of the microbiome and available resources. Here we describe examples of opportunities towards gaining understanding of the soil metaphenome.Jeanneau, L., Rowland, R., Inamdar, S., 2018. Molecular fingerprinting of particulate organic matter as a?new tool for its source apportionment: changes along a?headwater drainage in coarse, medium and fine particles as a?function of rainfalls. Biogeosciences 15, 973-985. the sources of particulate organic matter (POM) exported from catchments is important to understand the transfer of energy from soils to oceans. The suitability of investigating the molecular composition of POM by thermally assisted hydrolysis and methylation using tetramethylammonium hydroxide directly coupled to gas chromatography and mass spectrometry is presented. The results of this molecular-fingerprint approach were compared with previously published elemental (%?C, %?N) and isotopic data (δ13C, δ15N) acquired in a nested headwater catchment in the Piedmont region, eastern United States of America (12 and 79?ha). The concordance between these results highlights the effectiveness of this molecular tool as a valuable method for source fingerprinting of POM. It emphasizes litter as the main source of exported POM at the upstream location (80±14?%), with an increasing proportion of streambed (SBed) sediment remobilization downstream (42?±?29?%), specifically during events characterized by high rainfall amounts. At the upstream location, the source of POM seems to be controlled by the maximum and median hourly rainfall intensity. An added value of this method is to directly investigate chemical biomarkers and to mine their distributions in terms of biogeochemical functioning of an ecosystem. In this catchment, the distribution of plant-derived biomarkers characterizing lignin, cutin and suberin inputs were similar in SBed and litter, while the proportion of microbial markers was 4 times higher in SBed than in litter. These results indicate that SBed OM was largely from plant litter that has been processed by the aquatic microbial community.Jia, F., Lu, R., Liu, X., Zhao, C., Lv, Z., Gao, S., 2018. Palaeoenvironmental implications of a Holocene sequence of lacustrine-peat sediments from the desert-loess transitional zone in Northern China. Journal of Asian Earth Sciences 156, 167-173. high-resolution lacustrine-peat record from the desert-loess transitional zone in Northern China was obtained to reconstruct Holocene environmental change in the region. AMS 14C dates are used to provide a chronology. The results indicate that the site was a desert environment before 12.2?cal kyr BP, and was then occupied by a paleolake which started to shrink, with a wetland occurring from 6.2 to 3.0?cal kyr BP. Subsequently, the site became a seasonally water-filled depression. Based on the lithology and measurements of grain size and total organic carbon content, the climate changed from arid to humid at 12.2?cal kyr BP, and became more humid after 8.3?cal kyr BP. From 6.2 to 3.0?cal kyr BP, precipitation decreased but the climate remained at an optimum. After 3.0?cal kyr BP, the climate was dry overall but with several humid intervals. A comparison of paleoclimatic records from lacustrine and aeolian deposits from the region reveals a discrepancy about the nature of the early Holocene climate, and we conclude that this is because lacustrine sediments responded more sensitively to precipitation than aeolian deposits when the temperature was low. The environmental evolution of the region was synchronous with changes in the Asian summer monsoon (ASM), but temperature also played a key role in the early Holocene.Jing, D., Bainian, S., 2018. Early Cretaceous atmospheric CO2 estimates based on stomatal index of Pseudofrenelopsis papillosa (Cheirolepidiaceae) from southeast China. Cretaceous Research 85, 232-242. of the atmospheric carbon dioxide concentration levels were made for three time intervals of the Early Cretaceous using the stomatal indices of an extinct fossil conifer, Pseudofrenelopsis papillosa (Chow et Tsao) Cao ex Zhou. The fossil materials were collected from the upper Hauterivian, upper Aptian, and upper Albian of the Lower Cretaceous in the Fujian and Jiangxi Provinces of southeast China. The estimated paleo-CO2 (pCO2) was 600–1300 ppmv from the late Hauterivian to the late Albian based on the ratio between the stomatal indices of fossil species P. papillosa and those of four modern nearest living equivalent (NLE) species, using Carboniferous and recent standardizations. The results showed a low value of 595–957 ppmv in the late Hauterivian, and a high value of 805–1292 ppmv in the late Albian, which was only slightly higher than the value of 753–1210 ppmv in the late Aptian. Our calculated CO2 values were consistent with GECORB II, and similar to the previously published estimates of CO2 based on stomatal indices or carbon isotopes. Thus, it could be inferred that the stomatal index of P. papillosa is a potential indicator for estimating the pCO2 content during the geological history. Furthermore, the global mean land surface temperature (GMLST) was estimated based on the CO2 data. This showed that the change ratios of GMLST increased from 2.8 to 4.7 °C in the late Hauterivian to 3.6–5.5 °C in the late Albian and 3.8–5.7 °C in the late Aptian. It appears that the temperature gradually increased from the early to late Early Cretaceous.Jung, H., Baek, M., D’Elia, K.P., Boisvert, C., Currie, P.D., Tay, B.-H., Venkatesh, B., Brown, S.M., Heguy, A., Schoppik, D., 2018. The ancient origins of neural substrates for land walking. Cell 172, 667-682. is the predominant locomotor behavior expressed by land-dwelling vertebrates, but it is unknown when the neural circuits that are essential for limb control first appeared. Certain fish species display walking-like behaviors, raising the possibility that the underlying circuitry originated in primitive marine vertebrates. We show that the neural substrates of bipedalism are present in the little skate Leucoraja erinacea, whose common ancestor with tetrapods existed ～420 million years ago. Leucoraja exhibits core features of tetrapod locomotor gaits, including left-right alternation and reciprocal extension-flexion of the pelvic fins. Leucoraja also deploys a remarkably conserved Hox transcription factor-dependent program that is essential for selective innervation of fin/limb muscle. This network encodes peripheral connectivity modules that are distinct from those used in axial muscle-based swimming and has apparently been diminished in most modern fish. These findings indicate that the circuits that are essential for walking evolved through adaptation of a genetic regulatory network shared by all vertebrates with paired appendages.Jung, P., Briegel-Williams, L., Simon, A., Thyssen, A., Büdel, B., 2018. Uncovering biological soil crusts: carbon content and structure of intact Arctic, Antarctic and alpine biological soil crusts. Biogeosciences 15, 1149-1160., Antarctic and alpine biological soil crusts (BSCs) are formed by adhesion of soil particles to exopolysaccharides (EPSs) excreted by cyanobacterial and green algal communities, the pioneers and main primary producers in these habitats. These BSCs provide and influence many ecosystem services such as soil erodibility, soil formation and nitrogen (N) and carbon (C) cycles. In cold environments degradation rates are low and BSCs continuously increase soil organic C; therefore, these soils are considered to be CO2 sinks. This work provides a novel, non-destructive and highly comparable method to investigate intact BSCs with a focus on cyanobacteria and green algae and their contribution to soil organic C. A new terminology arose, based on confocal laser scanning microscopy (CLSM) 2-D biomaps, dividing BSCs into a photosynthetic active layer (PAL) made of active photoautotrophic organisms and a photosynthetic inactive layer (PIL) harbouring remnants of cyanobacteria and green algae glued together by their remaining EPSs. By the application of CLSM image analysis (CLSM–IA) to 3-D biomaps, C coming from photosynthetic active organisms could be visualized as depth profiles with C peaks at 0.5 to 2?mm depth. Additionally, the CO2 sink character of these cold soil habitats dominated by BSCs could be highlighted, demonstrating that the first cubic centimetre of soil consists of between 7 and 17?% total organic carbon, identified by loss on ignition.Kanapatskiy, T.A., Samylina, O.S., Plotnikov, A.O., Selivanova, E.A., Khlopko, Y.A., Kuznetsova, A.I., Rusanov, I.I., Zakharova, E.E., Pimenov, N.V., 2018. Microbial processes of organic matter production and decomposition in saline rivers of the Lake Elton area (Volgograd oblast, Russia). Microbiology 87, 66-78. rates of microbial processes and phylogenetic diversity of the microorganisms responsible for organic matter production and decomposition in the benthic communities and bottom sediments of the rivers Solyanka, Lantsug, Khara, Chernavka, and Bol’shaya Smorogda (Lake Elton area, Volgograd oblast, Russia) were studied. The biomass and primary production of cyano–bacterial communities varied significantly within the ranges of 20–903 mg Chl a/m2 and 0.2–21 mg C/(m2 h), respectively. Depending on the season, the share of anoxygenic CO2 fixation varied from 20% to the values comparable to the rate of oxygenic photosynthesis. The total heterotrophic activity of microbial communities determined as the rate of dark CO2 assimilation varied from 31 to 750 μmol/(dm3 day) in the mats and from 3 to 137 μmol/(dm3 day) in the sediments. The rates of sulfate reduction and hydrogenotrophic methanogenesis varied from 10 to 2621 μmol S/dm3 day) and from 1.5 to 323 nmol CH4/(dm3 day), respectively. High-throughput sequencing of the 16S rRNA genes in cyano–bacterial mats revealed microorganisms belonging to 20 phyla, with the sequences of Cyanobacteria, Proteobacteria, and Bacteroidetes being the most numerous. Original Russian Text ? T.A. Kanapatskiy, O.S. Samylina, A.O. Plotnikov, E.A. Selivanova, Yu.A. Khlopko, A.I. Kuznetsova, I.I. Rusanov, E.E. Zakharova, N.V. Pimenov, 2018, published in Mikrobiologiya, 2018, Vol. 87, No. 1, pp. 56–69.Kara-Gülbay, R., Korkmaz, S., Yaylal?-Abanuz, G., Erdo?an, M.S., 2018. Organic geochemistry and depositional environment of the Oltu Gemstone (coal) in the Erzurum Area, NE Anatolia, Turkey. Energy & Fuels 32, 1451-1463. Oltu Gemstone is located in the north of Oltu town (Erzurum–NE Turkey) city as a low rank coal. The Oltu Gemstone occurs as lenticular forms with thickness not exceeding centimeter size and lateral continuity of a few meters within the Liassic–Lower Malm Olurdere Formation consisting chiefly of claystone, sandstone, and volcanics. Coals that are operated as Oltu Gemstone are represented by very high TOC (67.39–78.56% wt), high hydrogen index (HI) values (314–379 mg HC/g TOC) and very low oxygen index (OI) values (1–3 mg CO2/g TOC). Low Pr/Ph ratios indicate that coals were prevented from oxidation and deposited under anoxic conditions. In Oltu Gemstone samples, C29 dominates over C27 and C28 steranes. In general, high (C19 + C20)/C23 tricyclic terpane, low Ts/(Ts + Tm), diasterane/sterane, and C31R/C30 hopane ratios were recorded. C29 MA steroids dominate with respect to others, and the C29/(C28 + C29) MA ratio is mostly high. DBT/P ratio of Oltu Gemstone samples has low values. Tmax values of Oltu Gemstone samples (between 416 and 436 °C) reflect immature–early mature character. 22S/(22R + 22S) homohopane, 20S/(20R + 20S), and ββ/(αα + ββ) sterane ratios and low moretane/hopane ratios, relatively high C28-TA/(C29-MA + C28-TA), MA(I)/MA(I + II), TA(I)/TA(I + II), MPI-3 (β/α MP), and MDR ratios indicate early mature character for the Oltu Gemstone samples.Karambeigi, M.S., Asl, A.H., Nasiri, M., 2018. Multi-objective optimization of microemulsion flooding for chemical enhanced oil recovery. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 73, Article 4. flooding is one of the most effective methods of Chemical Enhanced Oil Recovery (CEOR), particularly for the production of residual oil trapped in unconventional reservoirs. A critical step for successful application of this technique is to achieve a suitable formulation. Previous studies have almost focused on the technical aspects while considering both practical and economic matters as conflicting objectives has been neglected. In the present paper, the formulation of microemulsion is optimized based on the trade-off between scientific and financial responses using a hybrid workflow in which experimental design and artificial intelligence methodologies are composed. To appraise the efficiency of developed algorithm, a challenge case study is first evaluated and compared to previous approaches. Thereafter, the second case is examined in which a newly developed formulation of microemulsion for high temperature carbonate reservoirs is optimized. The outcomes of this multi-attribute workflow are compared to a single-objective algorithm. The results indicate the outstanding performance of the proposed approach for multi-objective optimization of microemulsion formulation. Eventually, the possible concerns regarding the application of microemulsion flooding in unconventional reservoirs are discussed.Karstens, J., Haflidason, H., Becker, L.W.M., Berndt, C., Rüpke, L., Planke, S., Liebetrau, V., Schmidt, M., Mienert, J., 2018. Glacigenic sedimentation pulses triggered post-glacial gas hydrate dissociation. Nature Communications 9, Article 635. amounts of methane are stored in continental margins as gas hydrates. They are stable under high pressure and low, but react sensitively to environmental changes. Bottom water temperature and sea level changes were considered as main contributors to gas hydrate dynamics after the last glaciation. However, here we show with numerical simulations that pulses of increased sedimentation dominantly controlled hydrate stability during the end of the last glaciation offshore mid-Norway. Sedimentation pulses triggered widespread gas hydrate dissociation and explains the formation of ubiquitous blowout pipes in water depths of 600 to 800?m. Maximum gas hydrate dissociation correlates spatially and temporally with the formation or reactivation of pockmarks, which is constrained by radiocarbon dating of Isorropodon nyeggaensis bivalve shells. Our results highlight that rapid changes of sedimentation can have a strong impact on gas hydrate systems affecting fluid flow and gas seepage activity, slope stability and the carbon cycle.Kato, S., Shibuya, T., Takaki, Y., Hirai, M., Nunoura, T., Suzuki, K., 2018. Genome-enabled metabolic reconstruction of dominant chemosynthetic colonizers in deep-sea massive sulfide deposits. Environmental Microbiology 20, 862-877. massive sulfide deposits remaining after ceasing of hydrothermal activity potentially provide energy for a chemosynthetic ecosystem in the dark, cold marine environments. Although yet-uncultivated bacteria in the phylum Nitrospirae and the class Deltaproteobacteria are known to dominate the microbial communities of sulfide deposits at and below the seafloor, their metabolic capabilities remain largely elusive. Here, we reveal the metabolic potential of these yet-uncultivated bacteria in hydrothermally inactive sulfide deposits collected at the Southern Mariana Trough by seafloor drilling. Near-complete genomes of the predominant bacterial members were recovered from shotgun metagenomic sequences. The genomic capabilities for CO2 and N2 fixation suggest that these bacteria are primary producers in the microbial ecosystem. Their genomes also encode versatile chemolithotrophic energy metabolisms, such as the oxidation of H2, sulfide and intermediate sulfur species including thiosulfate, all of which can be supplied by chemical reactions between seawater and metal sulfides. Notably, the presence of genes involved in thiosulfate oxidation in Nitrospirae and Deltaproteobacteria genomes is unusual. Our study strongly support the presence of a chemosynthetic ecosystem fuelled by the Earth's internal energy in the deep-sea massive sulfide deposits, and illustrates the unexpected metabolic capability of known bacterial taxonomic groups.Ke, C.-Y., Lu, G.-M., Li, Y.-B., Sun, W.-J., Zhang, Q.-Z., Zhang, X.-L., 2018. A pilot study on large-scale microbial enhanced oil recovery (MEOR) in Baolige Oilfield. International Biodeterioration & Biodegradation 127, 247-253. application of microbial enhanced oil recovery (MEOR) has been hindered by a lack of large-scale data-based guidelines for process design and operation. In the present work MEOR was investigated in both laboratory and large-scale oilfield studies. Six microbial strains were initially isolated from Baolige Oilfield in China. Laboratory based investigation showed that all six strains were able to decrease the oil viscosity. Two mixtures of strains exhibited greater reduction effects, i.e., 35% and 56%, respectively. The optimal nutrient concentration was found to be 1.0%. The mixtures of strains tested in laboratory core flooding based MEOR also confirmed their greater MEOR performance, i.e., MEOR levels of 9.1% and 13.2%, respectively, compared to that of any single strain ranging from 7.0% % to 8.7%. Using the strain mixture that had been selected under the laboratory based conditions, the pilot field study achieved a significant MEOR: 210,000 tons of crude oil produced over 43 months from 169 production wells. The research results obtained in this work including both laboratory and field studies can be potentially applied in other oilfields with similar geological and physical conditions, for large-scale MEOR process design and operation.Keery, J.S., Holden, P.B., Edwards, N.R., 2018. Sensitivity of the Eocene climate to CO2 and orbital variability. Climate of the Past 14, 215-238. early Eocene, from about 56?Ma, with high atmospheric CO2 levels, offers an analogue for the response of the Earth's climate system to anthropogenic fossil fuel burning. In this study, we present an ensemble of 50 Earth system model runs with an early Eocene palaeogeography and variation in the forcing values of atmospheric CO2 and the Earth's orbital parameters. Relationships between simple summary metrics of model outputs and the forcing parameters are identified by linear modelling, providing estimates of the relative magnitudes of the effects of atmospheric CO2 and each of the orbital parameters on important climatic features, including tropical–polar temperature difference, ocean–land temperature contrast, Asian, African and South (S.) American monsoon rains, and climate sensitivity. Our results indicate that although CO2 exerts a dominant control on most of the climatic features examined in this study, the orbital parameters also strongly influence important components of the ocean–atmosphere system in a greenhouse Earth. In our ensemble, atmospheric CO2 spans the range 280–3000?ppm, and this variation accounts for over 90?% of the effects on mean air temperature, southern winter high-latitude ocean–land temperature contrast and northern winter tropical–polar temperature difference. However, the variation of precession accounts for over 80?% of the influence of the forcing parameters on the Asian and African monsoon rainfall, and obliquity variation accounts for over 65?% of the effects on winter ocean–land temperature contrast in high northern latitudes and northern summer tropical–polar temperature difference. Our results indicate a bimodal climate sensitivity, with values of 4.36 and 2.54?°C, dependent on low or high states of atmospheric CO2 concentration, respectively, with a threshold at approximately 1000?ppm in this model, and due to a saturated vegetation–albedo feedback. Our method gives a quantitative ranking of the influence of each of the forcing parameters on key climatic model outputs, with additional spatial information from singular value decomposition providing insights into likely physical mechanisms. The results demonstrate the importance of orbital variation as an agent of change in climates of the past, and we demonstrate that emulators derived from our modelling output can be used as rapid and efficient surrogates of the full complexity model to provide estimates of climate conditions from any set of forcing parameters.Keles, E., Grenfell, J.L., Godolt, M., Stracke, B., Rauer, H., 2018. The effect of varying atmospheric pressure upon habitability and biosignatures of Earth-like planets. Astrobiology 18, 116-132. the possible climatic conditions on rocky extrasolar planets, and thereby their potential habitability, is one of the major subjects of exoplanet research. Determining how the climate, as well as potential atmospheric biosignatures, changes under different conditions is a key aspect when studying Earth-like exoplanets. One important property is the atmospheric mass, hence pressure and its influence on the climatic conditions. Therefore, the aim of the present study is to understand the influence of atmospheric mass on climate, hence habitability, and the spectral appearance of planets with Earth-like, that is, N2-O2 dominated, atmospheres orbiting the Sun at 1 AU. This work utilizes a 1D coupled, cloud-free, climate-photochemical atmospheric column model; varies atmospheric surface pressure from 0.5 to 30 bar; and investigates temperature and key species profiles, as well as emission and brightness temperature spectra in a range between 2 and 20?μm. Increasing the surface pressure up to 4 bar leads to an increase in the surface temperature due to increased greenhouse warming. Above this point, Rayleigh scattering dominates, and the surface temperature decreases, reaching surface temperatures below 273 K (approximately at ～34 bar surface pressure). For ozone, nitrous oxide, water, methane, and carbon dioxide, the spectral response either increases with surface temperature or pressure depending on the species. Masking effects occur, for example, for the bands of the biosignatures ozone and nitrous oxide by carbon dioxide, which could be visible in low carbon dioxide atmospheres.Keller, G., Mateo, P., Punekar, J., Khozyem, H., Gertsch, B., Spangenberg, J., Bitchong, A.M., Adatte, T., 2018. Environmental changes during the Cretaceous-Paleogene mass extinction and Paleocene-Eocene Thermal Maximum: Implications for the Anthropocene. Gondwana Research 56, 69-89. Cretaceous-Paleogene boundary (KPB) mass extinction (~ 66.02 Ma) and the Paleocene-Eocene Thermal Maximum (PETM) (~ 55.8 Ma) are two remarkable climatic and faunal events in Earth's history that have implications for the current Anthropocene global warming and rapid diversity loss. Here we evaluate these two events at the stratotype localities in Tunisia and Egypt based on climate warming and environmental responses recorded in faunal and geochemical proxies. The KPB mass extinction is commonly attributed to the Chicxulub impact, but Deccan volcanism appears as a major culprit. New mercury analysis reveals that major Deccan eruptions accelerated during the last 10 ky and reached the tipping point leading up to the mass extinction. During the PETM, climate warmed rapidly by ~ 5 °C, which is mainly attributed to methane degassing from seafloor sediments during global warming linked to the North Atlantic Igneous Province (NAIP). Biological effects were transient, marked by temporary absence of most planktic foraminifera due to ocean acidification followed by the return of the pre-PETM fauna and diversification. In contrast, the current rapid rise in atmospheric CO2 and climate warming are magnitudes faster than at the KPB or PETM events leading to predictions of a PETM-like response as best case scenario and rapidly approaching sixth mass extinction as worst-case scenario.Kelman, L.M., Kelman, Z., 2018. Do archaea need an origin of replication? Trends in Microbiology 26, 172-174. DNA replication starts at a specific region called an origin of replication. Until recently, all organisms were thought to require origins to replicate their chromosomes. It was recently discovered that some archaeal species do not utilize origins of replication under laboratory growth conditions.Khalifa, M.A., Mansurbeg, H., Morad, D., Morad, S., Al-Aasm, I.S., Spirov, P., Ceriani, A., De Ros, L.F., 2018. Quartz and Fe-dolomite cements record shifts in formation-water chemistry and hydrocarbon migration in Devonian shoreface sandstones, Ghadamis Basin, Libya. Journal of Sedimentary Research 88, 38-57. by quartz overgrowths and subsequently by carbonates is a very common global paragenetic phenomenon in sandstones of many basins that is poorly constrained in the literature. Integrated petrography, electron microprobe, stable isotopes, fluid inclusion microthermometry, and Raman spectroscopy have helped unravel the diagenetic conditions, fluid flow, and hydrocarbon migration during the development of quartz overgrowths and later Fe-dolomite cement in the Devonian shoreface sandstones (oil and gas reservoirs), Ghadamis Basin, NW Libya. The high homogenization temperatures of Fe-dolomite (Th = 119 to 140°C) together with its low δ18OVPDB values (–17.6‰ to –13.2‰) and saddle-crystal morphology suggest the flux of hot basinal brines. The fluid-inclusion microthermometry shows a shift from NaCl-dominated brines during quartz cementation (16.0 to 17.3 wt.% NaCl eq.) to NaCl and CaCl2-dominated brines during Fe-dolomite cementation (15.6 to 18.4 wt.% NaCl eq.). The latter brines probably circulated through overlying Mesozoic carbonate and evaporite strata before descending deep into the basin. The similarity in Th ranges for Fe-dolomite and quartz overgrowths, despite the shift in formation-water chemistry suggests precipitation under similar geothermal conditions. The presence of oil-filled inclusions in quartz overgrowths suggests that cementation occurred during oil migration, whereas the presence of methane in inclusions in the Fe-dolomite cement suggests precipitation during gas migration. This study shows that fluid inclusion microthermometry and Raman spectroscopy of the widespread paragenetic sequence of quartz overgrowths followed by carbonate cement are crucial to unravel changes in formation-water chemistry and fluid (including hydrocarbon) migration in sedimentary basins.Khan, M.N., Warrier, P., Peters, C.J., Koh, C.A., 2018. Advancements in hydrate phase equilibria and modeling of gas hydrates systems. Fluid Phase Equilibria 463, 48-61. hydrate phase behavior predictions are critical to petroleum and natural gas processing and design, and operation of process equipment. Inaccurate predictions of phase equilibria can also lead to erroneous design of process facilities and subsequently may cause safety hazards and flow assurance issues. This work reviews the experimental data on hydrate phase equilibria in the presence of inhibitors (Salts + Organic Inhibitors). The statistical thermodynamic model of van der Waals and Platteeuw for hydrate phase equilibria prediction is also critically reviewed. Recent studies have shown that the basic assumptions of the van der Waals and Platteeuw model, including the spherical symmetry of molecules, no guest–guest interactions, and no lattice distortions (due to guest molecules) can introduce errors in the predicted results. In addition, the limitations of the fluid phase models, which do not account for the effect of hydrogen bonding and electrolyte contributions, can lead to severe prediction errors in hydrate forming systems containing polar hydrate formers, inhibitors, and salts, especially at high concentrations. Thermodynamic predictions of gas hydrate phase equilibria for polar hydrate formers and inhibited systems (e.g., NaCl, KCl, CaCl2, and also methanol, ethanol, Ethane-1,2-diol) are of major concern because of the large errors in fluid phase equilibrium predictions. The unavailability of phase equilibria data, an appropriate electrolyte model, and an associative equation of state as well leads to various problems in predicting the properties of aqueous associating fluids and inhibited systems.Khodjaniyazova, S., Nazari, M., Garrard, K.P., Matos, M.P.V., Jackson, G.P., Muddiman, D.C., 2018. Characterization of the spectral accuracy of an Orbitrap mass analyzer using isotope ratio mass spectrometry. Analytical Chemistry 90, 1897-1906. matrix-assisted laser desorption electrospray ionization (IR-MALDESI) source coupled to the Q Exactive Plus has been extensively used in untargeted mass spectrometry imaging (MSI) analyses of biological tissue sections. Although the Orbitrap is a high-resolution and accurate-mass (HRAM) mass analyzer, these attributes alone cannot be used for the reliable identification of unknown analytes observed in complex biological matrices. Spectral accuracy (SA) is the ability of the mass spectrometer to accurately measure the isotopic distributions which, when used with high mass measurement accuracy (MMA), can facilitate the elucidation of a single elemental composition. To investigate the effects of different ion populations on an Orbitrap’s SA and MMA, a solution of caffeine, the tetrapeptide MRFA, and ultramark was analyzed using a Q Exactive Plus across eight distinct automatic gain control (AGC) targets. The same compounds from the same lot numbers were also individually analyzed using isotope ratio mass spectrometry (IRMS) to accurately determine the isotopic abundance of 13C, 15N, and 34S. We demonstrated that at optimum absolute ion abundances the Orbitrap can be used to accurately count carbons, nitrogens, and sulfurs in samples with varying masses. Additionally, absolute monoisotopic ion abundances required for high SA were empirically determined by using the expected (IRMS) and experimental (Orbitrap) isotopic distributions to calculate the Pearson chi-square test. These thresholds for absolute ion abundances can be used in untargeted MSI studies to shorten an identification list by rapidly screening for isotopic distributions whose absolute ion abundances are high enough to accurately estimate the number of atoms.Khormali, A., Sharifov, A.R., Torba, D.I., 2018. The control of asphaltene precipitation in oil wells. Petroleum Science and Technology 36, 443-449. instability can occur in petroleum reservoirs leading to permeability reduction and deposition in transportation pipes restricting fluid flow. In this work, effect of reservoir pressure on amount of asphaltene precipitation was investigated. Two different asphaltene inhibitors (a new developed and an industrial) were used for preventing asphaltene deposition under static and dynamic conditions. Viscosity measurements of the oil, core flooding experiments and transmittance measurement were conducted to understand asphaltene precipitation and deposition behavior as well inhibitor efficiencies. Optimum concentration of the new asphaltene inhibitor was 200 ppm. Experiments show inhabitation efficiency of new inhibitor can reach up to 90% and showed better performance when compared with industrial one. In addition, squeeze lifetime of new inhibitor was 1.86 times longer than the industrial inhibitor in carbonate core samples. In the presence of new inhibitor formation damage and percent of transmittance was lower than in the presence of industrial asphaltene inhibitor.Kidder, T.R., Henry, E.R., Arco, L.J., 2018. Rapid climate change-induced collapse of hunter-gatherer societies in the lower Mississippi River valley between ca. 3300 and 2780 cal yr BP. Science China Earth Sciences 61, 178-189. communities in the American Southeast reached an apogee of social and political complexity in the period between ca. 4200 and 3000 cal yr BP. In the lower Mississippi Valley (LMV) the Poverty Point culture defined this period of socio-political elaboration. However, following a significant period of climate change that led to exceptional flooding and a major reorganization of the course of the Mississippi River, this culture collapsed beginning ca. 3300–3200 cal yr BP and the LMV was abandoned for the subsequent 500 years. In this study, we use data from the Jaketown site in the Yazoo Basin of west-central Mississippi to refine the chronology of the climate event that caused the collapse of the Poverty Point culture. A large flood buried Poverty Point-era occupation deposits at Jaketown around 3310 cal yr BP. Lateral migration of the Mississippi River during flooding led to inundation of the Yazoo Basin and re-occupation of ancient river courses. A coarse sand stratum topped by a more than a meter-thick fining upward sediment package marks a crevasse deposit caused by a rupture of the natural levee at Jaketown. This levee breach was part of a larger pattern of erratic flooding throughout the LMV and is associated with major landscape evolution and the abandonment of Poverty Point sites within the valley. Early Woodland peoples re-colonized the crevasse surface after ca. 2780 cal yr BP. Following this event, the Jaketown site and the eastern Yazoo Basin witnessed a period of landscape stability that lasts to this day. These archaeological data demonstrate how climate change and natural disasters can lead to socio-political dissolution and reorganization even in relatively small-scale hunter-gatherer populations.Kiessling, W., Schobben, M., Ghaderi, A., Hairapetian, V., Leda, L., Korn, D., 2018. Pre–mass extinction decline of latest Permian ammonoids. Geology 46, 283-286. devastating end-Permian mass extinction is widely considered to have been caused by large-scale and rapid greenhouse gas release by Siberian magmatism. Although the proximate extinction mechanisms are disputed, there is widespread agreement that a major extinction pulse occurred immediately below the biostratigraphically defined Permian–Triassic boundary. Our statistical analyses of stratigraphic confidence intervals do not comply with a single end-Permian extinction pulse of ammonoids in Iran. High turnover rates and extinction pulses are observed over the last 700 k.y. of the Permian period in two widely separated sections representative of a larger area. Analyses of body sizes and morphological complexity support a gradual decline over the same interval. Similar pre–mass extinction declines and disturbances of the carbon cycle have sometimes been reported from other regions, suggesting a widespread, but often overlooked, environmental deterioration at a global scale, well before the traditional main extinction pulse.Kitadai, N., Nishiuchi, K., Nishii, A., Fukushi, K., 2018. Amorphous silica-promoted lysine dimerization: A thermodynamic prediction. Origins of Life and Evolution of Biospheres 48, 23-34. has long been suggested that mineral surfaces played a crucial role in the abiotic polymerization of amino acids that preceded the origin of life. Nevertheless, it remains unclear where the prebiotic process took place on the primitive Earth, because the amino acid–mineral interaction and its dependence on environmental conditions have yet to be understood adequately. Here we examined experimentally the adsorption of L-lysine (Lys) and its dimer (LysLys) on amorphous silica over a wide range of pH, ionic strength, adsorbate concentration, and the solid/water ratio, and determined the reaction stoichiometries and the equilibrium constants based on the extended triple-layer model (ETLM). The retrieved ETLM parameters were then used, in combination with the equilibrium constant for the peptide bond formation in bulk water, to calculate the Lys–LysLys equilibrium in the presence of amorphous silica under various aqueous conditions. Results showed that the silica surface favors Lys dimerization, and the influence varies greatly with changing environmental parameters. At slightly alkaline pH (pH?9) in the presence of a dilute NaCl (1?mM), the thermodynamically attainable LysLys from 0.1?mM Lys reached a concentration around 50 times larger than that calculated without silica. Because of the versatility of the ETLM, which has been applied to describe a wide variety of biomolecule–mineral interactions, future experiments with the reported methodology are expected to provide a significant constraint on the plausible geological settings for the condensation of monomers to polymers, and the subsequent chemical evolution of life.Kolomnikov, I.G., Efremov, A.M., Tikhomirova, T.I., Sorokina, N.M., Zolotov, Y.A., 2018. Early stages in the history of gas chromatography. Journal of Chromatography A 1537, 109-117. creation of gas chromatography is traditionally associated with the names of Nobel Prize winner Archer Martin and his colleagues Richard Synge and Anthony James. However, sometimes references to their predecessors can be found. An investigation conducted by the authors of this article not only confirmed the reliability of these references; but in fact led to the conclusion that by 1952, which is commonly believed to be the year when gas chromatography was born, many research papers had already been devoted to this method, mainly, in its gas-solid version. These papers are considered in this article.Kondrik, D.V., Pozdnyakov, D.V., Johannessen, O.M., 2018. Satellite evidence that E. huxleyi phytoplankton blooms weaken marine carbon sinks. Geophysical Research Letters 45, 846-854.: Phytoplankton blooms of the coccolithophore Emiliania huxleyi are known to produce CO2, causing less uptake of atmospheric CO2 by the ocean, but a global assessment of this phenomenon has so far not been quantified. Therefore, here we quantify the increase in CO2 partial pressure (ΔpCO2) at the ocean surface within E. huxleyi blooms for polar and subpolar seas using an 18 year ocean color time series (1998–2015). When normalized to pCO2 in the absence of bloom, the mean and maximum ΔpCO2 values within the bloom areas varied between 21.0%–43.3% and 31.6%–62.5%, respectively. These results might have appreciable implications for climatology, marine chemistry, and ecology.Plain Language Summary: Absorbing the heat fluxes emanating from the Earth's surface, atmospheric CO2 imparts to the atmosphere the property of a “greenhouse” as it redirects some fraction of the intercepted heat back to the oceans and land. Atmospheric CO2 emissions lead to the enhancement of the overall greenhouse effect. However, there is a group of marine algae called coccolithophores that may weaken the ocean CO2 sink. The present paper reports on our 18 year (1998–2015) satellite-based studies of a number of seas in the Atlantic, Arctic, and Pacific Oceans. We found that the maximum increase in CO2 partial pressure, ΔpCO2, in seawater within the target coccolithophore bloom areas could reach in some cases up to 63% with regard to pCO2 in the absence of bloom. Thus, it becomes clear that the role of such blooms might be very significant in shifts of the CO2 balance between the atmosphere and the ocean. This is particularly important as coccolithophore blooms occur also in the Southern Hemisphere where they are even more extensive. This finding might be consequential in terms of the problem of global climate change and also with regard to the ocean surface water chemistry and, more generally, marine ecology.Kong, F.-x., Sun, G.-d., Liu, Z.-p., 2018. Degradation of polycyclic aromatic hydrocarbons in soil mesocosms by microbial/plant bioaugmentation: Performance and mechanism. Chemosphere 198, 83-91. order to study the degradation of polycyclic aromatic hydrocarbons (PAHs) in an aged and highly contaminated soil, four bioremediation strategies (indigenous microorganisms, microbial bioaugmentation with a PAH-degrading and bioemulsifier-producing strain, Rhodococcus ruber Em1, plant bioaugmentation with Orychophragmus violaceus and their combination) were compared and the enhanced degradation mechanism was investigated in soil mesocosms. Degradation rates over a period of 175 days showed that Em1 combined with Orychophragmus violaceus promoted a significant enhancement of PAHs degradation. In inoculated microcosms with Rhodococcus ruberEm1, mineralization reached a lower level in the absence than in the presence of plants. Elimination of PAHs was significantly enhanced (increased by 54.45%) in the bioaugmented mesocosms. Quantitative PCR indicated that copy numbers of linA and RHD-like gene (encoding PAH-ring hydroxylating dioxygenase) in the mesocosm with plant were three and five times higher than those in the mesocosm without plant, respectively. Transcript copy numbers of RHD-like gene and 16S rRNA gene of strain Em1 in mesocosm with plant were two and four times higher than those in the mesocosm without plant, respectively. Taken together, the results of this study show that plants or Rhodococcus ruber Em1 enhance total PAHs removal, moreover their effects are necessarily cumulative by combined strains and plants.Konstantinov, K.K., Konstantinova, A.F., 2018. Chiral symmetry breaking in peptide systems during formation of life on Earth. Origins of Life and Evolution of Biospheres 48, 93-122. symmetry breaking in complex chemical systems with a large number of amino acids and a large number of similar reactions was considered. It was shown that effective averaging over similar reaction channels may result in very weak effective enantioselectivity of forward reactions, which does not allow most of the known models to result in chiral symmetry breaking during formation of life on Earth. Models with simple and catalytic synthesis of a single amino acid, formation of peptides up to length five, and sedimentation of insoluble pair of substances were considered. It was shown that depending on the model and the values of the parameters, chiral symmetry breaking may occur in up to about 10% out of all possible unique insoluble pair combinations even in the absence of any catalytic synthesis and that minimum total number of amino acids in the pair is 5. If weak enantioselective forward catalytic synthesis of amino acids is present, then the number of possible variants, in which chiral symmetry breaking may occur, increases substantially. It was shown that that the most interesting catalysts have zero or one amino acid of “incorrect” chirality. If the parameters of the model are adjusted in such a way to result in an increase of concentration of longer peptides, then catalysts with two amino acids of incorrect chirality start to appear at peptides of length five. Models of chiral symmetry breaking in the presence of epimerization were considered for peptides up to length three. It was shown that the range of parameters in which chiral symmetry breaking could occur significantly shrinks in comparison to previously considered models with peptides up to length two. An experiment of chiral symmetry breaking was proposed. The experiment consists of a three-step cycle: reversible catalytic synthesis of amino acids, reversible synthesis of peptides, and irreversible sedimentation of insoluble substances.Koolen, H.H.F., Gomes, A.F., de Moura, L.G.M., Marcano, F., Cardoso, F.M.R., Klitzke, C.F., Wojcik, R., Binkley, J., Patrick, J.S., Swarthout, R.F., Rosa, P.T.V., Gozzo, F.C., 2018. Integrative mass spectrometry strategy for fingerprinting and tentative structural characterization of asphaltenes. Fuel 220, 717-724. oils are characterized by high proportions of asphaltenes, a class of polyaromatic hydrocarbons whose structures remain unknown. Previous work based on asphaltene physical-chemical properties and extensive spectroscopic and computational methods has generated controversy about two possible general conformations: island and archipelago. To address this controversy, this study employed a systematic integrative approach involving ion mobility (IMS), theoretical calculations, ultra-high resolution mass spectrometry (UHR MS), and pyrolysis gas chromatography coupled to high-resolution mass spectrometry (Py-GC-HR MS) to evaluate the composition and structure of asphaltenes. Two Brazilian oils with different API grades (heavy and light) were analyzed and compared. The comparison of IMS data demonstrated that isobaric asphaltenes from light and heavy oils shared similar collisional cross sections (CCS) with different homologous series in the experiments. Two-dimensional (2D) difference mobility plots showed that minor compounds in these fractions possess different CCS. The combination of CCS data with UHR MS and Py-GC-HR MS still was not enough to indicate if there is a single asphaltene architecture in the studied samples. However, the obtained data were structurally slightly more consistent with the island architecture. Furthermore, the systematic combination of mass spectrometry techniques and calculations provided a reliable method for fingerprinting complex geological samples and providing structural information.K?seo?lu, D., Belt, S.T., Smik, L., Yao, H., Panieri, G., Knies, J., 2018. Complementary biomarker-based methods for characterising Arctic sea ice conditions: A case study comparison between multivariate analysis and the PIP25 index. Geochimica et Cosmochimica Acta 222, 406-420. discovery of IP25 as a qualitative biomarker proxy for Arctic sea ice and subsequent introduction of the so-called PIP25 index for semi-quantitative descriptions of sea ice conditions has significantly advanced our understanding of long-term paleo Arctic sea ice conditions over the past decade. We investigated the potential for classification tree (CT) models to provide a further approach to paleo Arctic sea ice reconstruction through analysis of a suite of highly branched isoprenoid (HBI) biomarkers in ca. 200 surface sediments from the Barents Sea. Four CT models constructed using different HBI assemblages revealed IP25 and an HBI triene as the most appropriate classifiers of sea ice conditions, achieving a >90% cross-validated classification rate. Additionally, lower model performance for locations in the Marginal Ice Zone (MIZ) highlighted difficulties in characterisation of this climatically-sensitive region. CT model classification and semi-quantitative PIP25-derived estimates of spring sea ice concentration (SpSIC) for four downcore records from the region were consistent, although agreement between proxy and satellite/observational records was weaker for a core from the west Svalbard margin, likely due to the highly variable sea ice conditions. The automatic selection of appropriate biomarkers for description of sea ice conditions, quantitative model assessment, and insensitivity to the c-factor used in the calculation of the PIP25 index are key attributes of the CT approach, and we provide an initial comparative assessment between these potentially complementary methods. The CT model should be capable of generating longer-term temporal shifts in sea ice conditions for the climatically sensitive Barents Sea.Koz?owska, M., Brudzinski, M.R., Friberg, P., Skoumal, R.J., Baxter, N.D., Currie, B.S., 2018. Maturity of nearby faults influences seismic hazard from hydraulic fracturing. Proceedings of the National Academy of Sciences 115, E1720.: Recent studies have focused on how wastewater disposal wells have caused dramatic increases in eastern US earthquakes. We focused instead on less common cases where hydraulic fracturing alone has caused earthquakes and found seismicity separated into two depth zones: a shallow zone on younger faults, with more small-magnitude earthquakes than expected, and a deeper zone on older faults, with larger magnitude earthquakes and seismicity continuing after fracturing stops. Hence, inducing deeper seismicity creates more hazard. Our observations are consistent with prior geologic, laboratory, and theoretical work indicating that age and maturity of faults causes the different seismicity patterns. We utilize data from well operators to demonstrate that both fluid pressure changes and rock stress transfer are needed to explain our observations.Abstract: Understanding the causes of human-induced earthquakes is paramount to reducing societal risk. We investigated five cases of seismicity associated with hydraulic fracturing (HF) in Ohio since 2013 that, because of their isolation from other injection activities, provide an ideal setting for studying the relations between high-pressure injection and earthquakes. Our analysis revealed two distinct groups: (i) deeper earthquakes in the Precambrian basement, with larger magnitudes (M > 2), b-values < 1, and many post–shut-in earthquakes, versus (ii) shallower earthquakes in Paleozoic rocks ～400 m below HF, with smaller magnitudes (M < 1), b-values > 1.5, and few post–shut-in earthquakes. Based on geologic history, laboratory experiments, and fault modeling, we interpret the deep seismicity as slip on more mature faults in older crystalline rocks and the shallow seismicity as slip on immature faults in younger sedimentary rocks. This suggests that HF inducing deeper seismicity may pose higher seismic hazards. Wells inducing deeper seismicity produced more water than wells with shallow seismicity, indicating more extensive hydrologic connections outside the target formation, consistent with pore pressure diffusion influencing seismicity. However, for both groups, the 2 to 3 h between onset of HF and seismicity is too short for typical fluid pressure diffusion rates across distances of ～1 km and argues for poroelastic stress transfer also having a primary influence on seismicity.Krajewski, L.C., Lobodin, V.V., Johansen, C., Bartges, T.E., Maksimova, E.V., MacDonald, I.R., Marshall, A.G., 2018. Linking natural oil seeps from the Gulf of Mexico to their origin by use of Fourier transform ion cyclotron resonance mass spectrometry. Environmental Science & Technology 52, 1365-1374. report chemical characterization of natural oil seeps from the Gulf of Mexico by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and Gas Chromatography/Atmospheric Pressure Chemical Ionization Mass Spectrometry (GC/APCI-MS), to highlight how FT-ICR MS can also be employed as a means to determine petroleum connectivity, in addition to traditional GC/MS techniques. The source of petroleum is the Green Canyon (GC) 600 lease block in the Gulf of Mexico. Within GC600, two natural oil seepage zones, Mega Plume and Birthday Candles, continuously release hydrocarbons and develop persistent oil slicks at the sea surface above them. We chemically trace the petroleum from the surface oil slicks to the Mega Plume seep itself, and further to a petroleum reservoir 5 km away in lease block GC645 (Holstein Reservoir). We establish the connectivity between oil samples and confirm a common geological origin for the oil slicks, oil seep, and reservoir oil. The ratios of seven common petroleum biomarkers detected by GC/APCI-MS display clear similarity between the GC600 and GC645 samples, as well as a distinct difference from another reservoir oil collected ～300 km away (Macondo crude oil from MC252 lease block). FT-ICR MS and principal component analysis (PCA) demonstrate further similarities between the GC600 and GC645 samples that distinctly differ from MC252. A common geographical origin is postulated for the GC600/GC645 samples, with petroleum migrating from the GC645 reservoir to the oil seeps found in GC600 and up through the water column to the sea surface as an oil slick.Kuang, W., Saraji, S., Piri, M., 2018. A systematic experimental investigation on the synergistic effects of aqueous nanofluids on interfacial properties and their implications for enhanced oil recovery. Fuel 220, 849-870. have been proposed as potential enhanced oil recovery agents and additives to hydraulic fracturing fluids. The underlying mechanisms responsible for effectiveness of these fluids, however, are not well understood. In this study, we experimentally investigate synergistic effects of aqueous nanofluids on interfacial properties of oil/brine/rock systems and their role in influencing oil displacement from sandstone and carbonate rock samples. The nanofluids were prepared by dispersing three widely-used nanoparticles (i.e., SiOx , Al2O3, and TiO2) and five different chemical agents (i.e., oleic acid, polyacrylic acid, a cationic, an anionic, and a nonionic surfactant) in base brine solutions. The efficacy of the mixtures was examined using a framework that including a comprehensive stability analysis, IFT and wettability characterizations, and oil recovery tests at ambient as well as high pressure and high temperature conditions (i.e., spontaneous imbibition and core-flooding experiments, respectively). Effects of stable nanofluids, identified from stability analysis, on interfacial tension and dynamic contact angle were carefully investigated. We show that co-adsorption and self-structuring of nanoaggregates and chemical agents at the solid interface leads to wettability alteration. Both spontaneous imbibition and high pressure and high temperature core-flooding results reveal the effectiveness of SiOx ?+?nonionic surfactant nanofluid in enhancing oil recovery in Berea sandstone due to a synergistic effect between nanoparticles and surfactant molecules. In contrast, the stability of nanofluids was highly compromised in Edwards limestone due to dissolution and interaction of calcium ions with nanoaggregates at high temperature. This was evident in the drastic difference between oil recoveries obtained through ambient-temperature spontaneous imbibition and high-temperature core-flooding experiments conducted on carbonate core samples. Finally, we provide new insights on interfacial interactions in nanofluid/oil/rock systems as they relate to wettability alteration, IFT reduction, and the effect of dissolved ions such as calcium in carbonate rocks. We use this improved understanding to explain the recovery trends observed in our study.Kumari, S., Regar, R.K., Manickam, N., 2018. Improved polycyclic aromatic hydrocarbon degradation in a crude oil by individual and a consortium of bacteria. Bioresource Technology 254, 174-179. this study, we report the ability of Stenotrophomonas maltophilia, Ochrobactrum anthropi, Pseudomonas mendocina, Microbacterium esteraromaticum and Pseudomonas aeruginosa to degrade multiple polycyclic aromatic hydrocarbons (PAHs) present in crude oil. The PAHs in the crude oil sample obtained from Digboi oil refinery, India were estimated to be naphthalene (10.0?mg?L?1), fluorene (1.9?mg?L?1), phenanthrene (3.5?mg?L?1) and benzo(b)fluoranthene (6.5?mg?L?1). Exposure of individual bacteria to crude oil showed high rate of biodegradation of specific PAHs by M. esteraromaticum, 81.4%-naphthalene; P. aeruginosa, 67.1%-phenanthrene and 61.0%-benzo(b)fluoranthene; S. maltophilia, 47.9%-fluorene in 45?days. However, consortium of these bacteria showed enhanced biodegradation of 89.1%-naphthalene, 63.8%-fluorene, 81% of phenanthrene and 72.8% benzo(b)fluoranthene in the crude oil. The degradation was further improved up to 10% by consortium on addition of 40?μg?mL?1 rhamnolipid JBR-425 biosurfactant. These results suggest that the developed bacterial consortium has significant potential in PAH remediation.Kurek, M.R., Gilhooly, W.P., Druschel, G.K., O'Beirne, M.D., Werne, J.P., 2018. The use of dithiothreitol for the quantitative analysis of elemental sulfur concentrations and isotopes in environmental samples. Chemical Geology 481, 18-26. the concentration and isotopic composition of elemental sulfur in modern and ancient environments is essential to improved interpretation of the mechanisms and pathways of sulfur utilization in biogeochemical cycles. Elemental sulfur can be extracted from sediment or water samples and quantified by converting to hydrogen sulfide. Alternatively, elemental sulfur concentrations can themselves be analyzed using HPLC and other methodologies; however, the preparation and analysis times can be long and these methods are not amenable to stable isotopic analysis. Current reduction methods involve the use of costly and specialized glassware in addition to toxins such as chromium chloride or cyanide to reduce the sulfur to hydrogen sulfide. The novel reduction method presented here uses dithiothreitol (DTT) as a less toxic reducing agent to obtain both elemental sulfur concentrations and isotopic composition from the same sample. The sample is dissolved in an aqueous or organic liquid medium and upon reaction with DTT, the elemental sulfur is volatilized as hydrogen sulfide and collected in a sulfide trap using an inexpensive gas extraction apparatus. The evolved sulfide concentrations can easily be measured for concentration, by absorbance spectrophotometery or voltammetry techniques, and then analyzed for sulfur isotopic composition. The procedure is quantitative at >93% recovery to dissolved elemental sulfur with no observed sulfur isotope fractionation during reduction and recovery. Controlled experiments also demonstrate that DTT is not reactive to sulfate, sulfite, pyrite, or organic sulfur.Lagree, K., Desai, J.V., Finkel, J.S., Lanni, F., 2018. Microscopy of fungal biofilms. Current Opinion in Microbiology 43, 100-107. biofilms are heterogeneous, surface-associated colonies comprised of filamentous hyphae (chains of elongated cells), pseudohyphal cells, yeast-form cells, and various forms of extracellular matrix. When grown on a substratum under liquid culture medium, the microbial fungus Candida albicans forms dense biofilms that range in thickness from 100 to 600 μm. Apical hyphae in the medium and invasive hyphae in the substratum may add greatly to the thickness and complexity of the biofilm. Because of the heterogeneity of the structure, and the large refractive index differences between cell walls, cytoplasm, and medium, fungal biofilms appear optically opaque. For fixed specimens that can be transferred out of an aqueous medium, refractive index matching methods provide a high degree of clarification. Confocal scanning, 2-photon scanning, or selective-plane illumination microscopy then can be used to obtain high-quality image data spanning the full thickness of the biofilm. Using refractive index matching and confocal microscopy, we have imaged many interesting features within wild-type, mutant, and engineered biofilms, including cellular phenotypes that vary with position, the effect of growth conditions, and gene expression through reporter constructs. This approach greatly expands the range of microscopical studies, allowing researchers to observe and quantify specific phenomena within medically or industrially relevant forms of microbial growth.Lai, H., Li, M., Liu, J., Mao, F., Xiao, H., He, W., Yang, L., 2018. Organic geochemical characteristics and depositional models of Upper Cretaceous marine source rocks in the Termit Basin, Niger. Palaeogeography, Palaeoclimatology, Palaeoecology 495, 292-308. Cretaceous marine mudstones are widely known as the most important source rocks in the Western African rift basins. However, geochemical studies on their occurrence and formation mechanism are scarce. In this study, a detailed geochemical investigation within a sequence stratigraphic framework was carried out to reconstruct the palaeoenvironmental conditions and to establish models on the depositional history of Upper Cretaceous marine mudstones in the Termit Basin (Niger), western African. A total of six third-order sequences (DSQ1, DSQ2, YSQ1, YSQ2, YSQ3 and MSQ1, from bottom to top) were identified in the Upper Cretaceous. The distribution of biomarkers from 33 mudstone samples in different sequences indicate that mudstones from YSQ3 were mainly deposited in a suboxic to oxic environment, with significant contributions from mixed terrigenous higher plants and lower aquatic organisms in fresh-brackish water column. In contrast, the other sequences (YSQ2, YSQ1, DSQ2 and DSQ1) mainly represent a suboxic to anoxic marine environment with a stratified water column (0.59?<?pristane/phytane?<?1.71, 20.78%?<?gammacerane/C30 hopane?<?52.23%), dominated by marine aquatic organisms such as algae and bacteria. Accumulation models of organic matter (OM) for different sequences were established to delineate the combined effects of a variety of geological and environmental controlling factors, such as global sea-level fluctuations, seawater circulation patterns, palaeoclimatic conditions, input of terrigenous OM and inherited rift palaeotopography. Most notably, the relative changes of global sea level and the patterns of seawater circulation were the critical factors controlling the sources, depositional conditions and preservation of organic matter in the Termit Basin. Organic matter rich marine mudstones in Termit Basin are closely related to high supply of terrigenous OM. This study not only provides practical depositional models for marine mudstones in the Termit Basin, but also improves the general understanding of marine organic matter accumulation in a relatively restricted inland rift environment.Landing, E., Antcliffe, J.B., Geyer, G., Kouchinsky, A., Bowser, S.S., Andreas, A., 2018. Early evolution of colonial animals (Ediacaran Evolutionary Radiation–Cambrian Evolutionary Radiation–Great Ordovician Biodiversification Interval). Earth-Science Reviews 178, 105-135. of eumetazoan modular coloniality gives a new perspective to Ediacaran–Ordovician animal diversification. Highly integrated eumetazoan colonies (porpitids [“chondrophorines”], pennatulacean octocorals, anthozoans) prove to be unknown in the Ediacaran. Ediacaran Evolutionary Radiation (EER, new term) fossils include macroscopic and multicellular remains that cannot be compellingly related to any modern group. Claims of eumetazoan coloniality in the Ediacaran are questionable. The subsequent Cambrian Evolutionary Radiation (CER, terminal Ediacaran–late early Cambrian) records appearance and diversification of deep burrowers and a relatively abrupt development of biomineralization. The CER began in a transition zone that spans the Ediacaran–Cambrian boundary and includes the final few million years of the Ediacaran. The early CER has pseudocolonial(?) Corumbella that may be related to some Phanerozoic taxa (conulariids) and records appearance of the first macroscopic biomineralised organisms (Cloudina, Namacalathus, Namapoikea), which may not be eumetazoans. Modular eumetazoans dominate and define many Ordovician and younger habitats (coral, bryozoan, sabellitid reefs; pelagic larvaceans, salps, early–middle Palaeozoic graptolites), but eumetazoan coloniality largely “missed” the EER and CER. All purported Ediacaran–Ordovician porpitids (“chondophorines”) and pennatulaceans are not colonial eumetazoans. Only in the late early Cambrian (late CER) or early middle Cambrian do a few modular colonial eumetazoans first occur as fossils. These include Sphenothallus (available evidence precludes Torellella coloniality), some corals (colonial “coralomorphs”), and lower middle Cambrian graptolithoids. Modular eumetazoan colonies (corals, graptolithoids) in the late early and early middle Cambrian (late Epoch 2–early Epoch 3) and appearance of mid-water predators (cephalopods, euconodonts) and bryozoans in the late Cambrian–earliest Ordovician (late Furongian–early Tremadocian) are the root for the Great Ordovician Biodiversification Interval (GOBI, new term) and diverse later Phanerozoic communities.Large, R.R., Mukherjee, I., Zhukova, I., Corkrey, R., Stepanov, A., Danyushevsky, L.V., 2018. Role of upper-most crustal composition in the evolution of the Precambrian ocean–atmosphere system. Earth and Planetary Science Letters 487, 44-53. research has emphasized the potential relationships between supercontinent cycles, mountain building, nutrient flux, ocean–atmosphere chemistry and the origin of life. The composition of the Upper-Most Continental Crust (UMCC) also figures prominently in these relationships, and yet little detailed data on each component of this complex relationship has been available for assessment.Here we provide a new set of data on the trace element concentrations, including the Rare Earth Elements (REE), in the matrix of 52 marine black shale formations spread globally through the Archean and Proterozoic. The data support previous studies on the temporal geochemistry of shales, but with some important differences. Results indicate a change in provenance of the black shales (upper-most crustal composition), from more mafic in the Archean prior to 2700 Ma, to more felsic from 2700 to 2200 Ma, followed by a return to mafic compositions from 2200 to 1850 Ma. Around 1850 to 1800 Ma there is a rapid change to uniform felsic compositions, which remained for a billion years to 800 Ma. The shale matrix geochemistry supports the assertion that the average upper-most continental source rocks for the shales changed from a mix of felsic, mafic and ultramafic prior to 2700 Ma to more felsic after 1850 Ma, with an extended transition period between. The return to more mafic UMCC from 2200 to 1850 Ma is supported by the frequency of Large Igneous Provinces (LIPs) and banded iron formations, which suggest a peak in major mantle-connected plume events and associated Fe-rich hydrothermal activity over this period. Support for the change to felsic UMCC around 1850 Ma is provided by previous geological data which shows that felsic magmas, including, A-type granites and K–Th–U-rich granites intruded vast areas of the continental crust, peaking around 1850 Ma and declining to 1000 Ma.The implications of this change in UMCC are far reaching and may go some way to explain the distinct features of the Boring Billion (1800–800 Ma). Firstly, because mafic–ultramafic rocks contain significantly higher levels of the bio-essential nutrient elements (e.g. Fe, P, Ni, Cr, Co, Cu, Se, Mn, Zn) compared with felsic rocks, the flux of macro- and micro-nutrients to the ocean would have decreased significantly post 1850 Ma. This would have contributed to a drop in productivity and a drop in atmosphere O2 as suggested by the marine pyrite proxy. In addition, a change from mafic to felsic dominant composition of the UMCC post 1850 Ma, would have led to a decrease in the erosive flux of Ca and Mg to the ocean, affecting the oceanic carbonate equilibrium and likely contributing to a rise in atmosphere CO2.On this basis, we speculate that the commencement of the middle Proterozoic, commonly known as the Boring Billion period from 1800 to 800 Ma, marks the start of an extended time in Earth's evolution when the UMCC became dominated by felsic rocks, particularly K–U–Th–anorogenic granites. This led to a period of anomalously low concentrations of bio-essential trace elements, but elevated REE, U, Th, Pb, Tl, Rb/Al and K/Na in the oceans.Laruelle, G.G., Cai, W.-J., Hu, X., Gruber, N., Mackenzie, F.T., Regnier, P., 2018. Continental shelves as a variable but increasing global sink for atmospheric carbon dioxide. Nature Communications 9, Article 454. has been speculated that the partial pressure of carbon dioxide (pCO2) in shelf waters may lag the rise in atmospheric CO2. Here, we show that this is the case across many shelf regions, implying a tendency for enhanced shelf uptake of atmospheric CO2. This result is based on analysis of long-term trends in the air–sea pCO2 gradient (ΔpCO2) using a global surface ocean pCO2 database spanning a period of up to 35 years. Using wintertime data only, we find that ΔpCO2 increased in 653 of the 825 0.5° cells for which a trend could be calculated, with 325 of these cells showing a significant increase in excess of +0.5?μatm?yr?1 (p?<?0.05). Although noisier, the deseasonalized annual data suggest similar results. If this were a global trend, it would support the idea that shelves might have switched from a source to a sink of CO2 during the last century.Lash, G.G., 2018. Significance of stable carbon isotope trends in carbonate concretions formed in association with anaerobic oxidation of methane (AOM), Middle and Upper Devonian shale succession, western New York State, USA. Marine and Petroleum Geology 91, 470-479. concretions are concentrated along discrete stratigraphic horizons within Middle and Upper Devonian carbonaceous black and organic-deficient gray shale of western New York State. Textural characteristics preserved throughout studied concretions, including a clay grain microfabric typical of flocculated clay and spherical algal cysts, are consistent with a model entailing the formation of low-density, compaction-resistant calcium carbonate masses at shallow burial depth, within the zone of bacterial sulfate reduction. Burial of nascent concretions to the sulfate methane transition zone (SMTZ) was accompanied by the nearly complete infilling of porosity, the diagenetic consequence of the anaerobic oxidation of methane (AOM). Each concretionary horizon, then, defines the position of the SMTZ stabilized during an episode of reduced sedimentation rate. Most analyzed concretions (75%) of the Middle Devonian Marcellus Formation into the Upper Devonian Gowanda Formation display center-to-edge profiles of increasing bulk δ13C; far fewer concretions are characterized by radial profiles of decreasing δ13C. The common radial profiles of increasing δ13C can be attributed to AOM-related kinetic carbon isotope fractionation under diagenetic conditions of limited methane, which favors the production of dissolved inorganic carbon of increasing δ13C. Less common concretions displaying center-to-edge profiles of diminishing δ13C may record the anaerobic oxidation of more strongly 13C-depleted methane produced by carbon dioxide reduction, methanogenesis related to the degradation of organic matter within and near the SMTZ, or AOM back flux, an enzyme-mediated equilibrium isotope effect. These processes are favored by sulfate-limited diagenetic conditions more typical of the lower SMTZ and immediately underlying upper methanogenic zone (MEZ). Contradictory isotope profiles of texturally similar concretions can be accounted for by diagenesis associated with an extended SMTZ (ESMTZ) comprising the methane-limited SMTZ and the underlying sulfate-deficient upper MEZ. Vertical shifts of the diagenetic horizons of the ESMTZ induced by variable methane flux would have juxtaposed concretions displaying seemingly incompatible isotopic histories.Lauer, N.E., Warner, N.R., Vengosh, A., 2018. Sources of radium accumulation in stream sediments near disposal sites in Pennsylvania: Implications for disposal of conventional oil and gas wastewater. Environmental Science & Technology 52, 955-962. Pennsylvania, Appalachian oil and gas wastewaters (OGW) are permitted for release to surface waters after some treatment by centralized waste treatment (CWT) facilities. While this practice was largely discontinued in 2011 for unconventional Marcellus OGW at facilities permitted to release high salinity effluents, it continues for conventional OGW. This study aimed to evaluate the environmental implications of the policy allowing the disposal of conventional OGW. We collected stream sediments from three disposal sites receiving treated OGW between 2014 and 2017 and measured 228Ra, 226Ra, and their decay products, 228Th and 210Pb, respectively. We consistently found elevated activities of 228Ra and 226Ra in stream sediments in the vicinity of the outfall (total Ra = 90–25,000 Bq/kg) compared to upstream sediments (20–80 Bq/kg). In 2015 and 2017, 228Th/228Ra activity ratios in sediments from two disposal sites were relatively low (0.2–0.7), indicating that a portion of the Ra has accumulated in the sediments in recent (<3) years, when no unconventional Marcellus OGW was reportedly discharged. 228Ra/226Ra activity ratios were also higher than what would be expected solely from disposal of low 228Ra/226Ra Marcellus OGW. Based on these variations, we concluded that recent disposal of treated conventional OGW is the source of high Ra in stream sediments at CWT facility disposal sites. Consequently, policies pertaining to the disposal of only unconventional fluids are not adequate in preventing radioactive contamination in sediments at disposal sites, and the permission to release treated Ra-rich conventional OGW through CWT facilities should be reconsidered.Lee, S.A., Kim, G., 2018. Sources, fluxes, and behaviors of fluorescent dissolved organic matter (FDOM) in the Nakdong River Estuary, Korea. Biogeosciences 15, 1115-1122. monitored seasonal variations in dissolved organic carbon (DOC), the stable carbon isotope of DOC (δ13C-DOC), and fluorescent dissolved organic matter (FDOM) in water samples from a fixed station in the Nakdong River Estuary, Korea. Sampling was performed every hour during spring tide once a month from October 2014 to August 2015. The concentrations of DOC and humic-like FDOM showed significant negative correlations against salinity (r2?=??0.42–0.98, p?<?0.0001), indicating that the river-originated DOM components were the major source and behave conservatively in the estuarine mixing zone. The extrapolated δ13C-DOC values (?27.5 to ?24.5?‰) in fresh water confirm that both components are mainly of terrestrial origin. The slopes of humic-like FDOM against salinity were 60–80?% higher in the summer and fall due to higher terrestrial production of humic-like FDOM. The slopes of protein-like FDOM against salinity, however, were 70–80?% higher in spring due to higher biological production in river water. Our results suggest that there are large seasonal changes in riverine fluxes of humic- and protein-like FDOM to the ocean.Lemos, B.C., Gilles, V., Gon?alves, G.R., de Castro, E.V.R., Delarmelina, M., Carneiro, J.W.d.M., Greco, S.J., 2018. Synthesis, structure-activity relationship and evaluation of new non-polymeric chemical additives based on naphthoquinone derivatives as wax precipitation inhibitors and pour point depressants to petroleum. Fuel 220, 200-209. deposition is one of the major flow problems for petroleum transportation and production. In this context, the development of more efficient methods to remediate paraffin precipitation has received great attention within the oil industries. In the present study, eight new long-chain esters were prepared in less than four synthetic steps and in high yields (84–97%). Seven of them contain naphthoquinone nuclei, and one presents a cyclohexyl group. The new molecules were tested as non-polymer wax precipitation inhibitors and pour point depressants. Calorimetric experiments were employed to identify the effect of four pre-determined chemical groups within the molecules and to set out the best components for maximized inhibition: (i) the length of alkyl chain in the ester group, (ii) the length of the alkyl chain separating the polar nuclei and the ester group, (iii) the heteroatom bonded to the polar nuclei, and (iv) the importance of the naphthoquinone nuclei. After determination of the pour point and wax appearance temperature (WAT) of Brazilian oils by differential scanning calorimetry (DSC), the highest efficiency was observed for naphthoquinone esters derived from stearic and palmitic acids when containing two methylene groups as a separator and nitrogen as the heteroatom. These new additives present better results than the commercially available polymer-based inhibitors in all tested samples, even when applied at smaller concentrations, compared to many other polymer-based inhibitors reported in the literature. The importance of the naphthoquinone moiety as the polar portion of the inhibitor was confirmed when it was replaced by a cyclohexyl group. Molecular modeling and X-ray diffraction studies were also carried out to rationalize the relationship between structure and activity and the action mechanism of these new chemical additives.Lenton, T.M., Daines, S.J., Mills, B.J.W., 2018. COPSE reloaded: An improved model of biogeochemical cycling over Phanerozoic time. Earth-Science Reviews 178, 1-28. ‘COPSE’ (Carbon, Oxygen, Phosphorus, Sulphur and Evolution) biogeochemical model predicts the coupled histories and controls on atmospheric O2, CO2 and ocean composition over Phanerozoic time. The forwards modelling approach utilized in COPSE makes it a useful tool for testing mechanistic hypotheses against geochemical data and it has been extended and altered a number of times since being published in 2004. Here we undertake a wholesale revision of the model, incorporating: (1) elaboration and updating of the external forcing factors; (2) improved representation of existing processes, including plant effects on weathering and ocean anoxia; (3) inclusion of additional processes and tracers, including seafloor weathering, volcanic rock weathering and 87Sr/86Sr; (4) updating of the present-day baseline fluxes; and (5) a more efficient and robust numerical scheme. A key aim is to explore how sensitive predictions of atmospheric CO2, O2 and ocean composition are to model updates and ongoing uncertainties. The revised model reasonably captures the long-term trends in Phanerozoic geochemical proxies for atmospheric pCO2, pO2, ocean [SO4], carbonate δ13C, sulphate δ34S and carbonate 87Sr/86Sr. It predicts a two-phase drawdown of atmospheric CO2 with the rise of land plants and associated cooling phases in the Late Ordovician and Devonian-early Carboniferous, followed by broad peaks of atmospheric CO2 and temperature in the Triassic and mid-Cretaceous – although some of the structure in the CO2 proxy record is missed. The model robustly predicts a mid-Paleozoic oxygenation event due to the earliest land plants, with O2 rising from ~ 5% to > 17% of the atmosphere and oxygenating the ocean. Thereafter, atmospheric O2 is effectively regulated with remaining fluctuations being a Carboniferous–Permian O2 peak ~ 26% linked to burial of terrestrial organic matter in coal swamps, a Triassic–Jurassic O2 minimum ~ 21% linked to low uplift, a Cretaceous O2 peak ~ 26% linked to high degassing and weathering fluxes, and a Cenozoic O2 decline.Li, J., Wang, X., Wang, B., Zhao, J., Fang, Y., 2018. Investigation on the fates of vanadium and nickel during co-gasification of petroleum coke with biomass. Bioresource Technology 257, 47-53. study investigates the volatilization behaviors and mineral transformation of vanadium and nickel during co-gasification of petroleum coke with biomass. Moreover, the evolution of occurrence modes of vanadium and nickel was also determined by the method of sequential chemical extraction. The results show that the volatilities of vanadium and nickel in petroleum coke have a certain level of growth with an increase in the temperature. With the addition of biomass, their volatilities both show an obvious decrease. Organic matter and stable forms are the dominant chemical forms of vanadium and nickel. After gasification, organic-bound vanadium and nickel decompose completely and convert into other chemical forms. The crystalline phases of vanadium trioxide, coulsonite, nickel sulfide, and elemental nickel are clearly present in petroleum coke and biomass gasification ashes. When the addition of biomass reaches 60?wt%, the diffraction peaks of orthovanadate are found while that of vanadium trioxide disappear.Li, M., Wang, T.G., Xiao, Z., Fang, R., Ni, Z., Deng, W., Tang, Y., Zhang, C., Yang, L., 2018. Practical application of reservoir geochemistry in petroleum exploration: Case study from a Paleozoic carbonate reservoir in the Tarim Basin (northwestern China). Energy & Fuels 32, 1230-1241. geochemistry has a practical application in petroleum exploration. A typical Paleozoic carbonate oilfield was selected from the Tabei Uplift of the Tarim Basin (northwestern China) to exhibit the method, application, and exploration implications of reservoir geochemistry. Oil–oil correlation indicates that all oils analyzed in this study belong to one single oil group. The overall oil migration direction traced by selected organic molecular markers is from the southern to the northern regions of the Halahatang region. The source kitchen for current oil accumulations in the carbonate reservoir is predicted to locate to the south of this oilfield, most likely between the Awati and Manjiaer depressions. Based on the characteristics of hydrocarbon-bearing inclusions and the histograms of the homogenization temperatures (Th) and ice-melting temperatures of associated aqueous inclusions, the oil charging temperatures were obtained. The stratigraphic-burial and geothermal histories for representative individual well were reconstructed using one-dimensional basin modeling. We concluded that the Paleozoic oil reservoir has been charged twice during its oil charging history: first from 419 to 410 Ma and second from 16 to 8 Ma. The preservation conditions for early filling oil accumulations and the mixture of oils charged during the two filling phases have controlled the density and chemical compositions of present oil accumulations. The filling points and preferential pathway indicated by isopleth maps of molecular geochemical indicators are highly indicative of oil reservoirs with high yields. It is concluded that reservoir geochemistry can be utilized, not only to determine oil migration direction and to predict the location of source kitchens, but also for favorable charging pathway and potentially prolific prospecting zones. This study suggests that traps in the southern region along the preferred oil charging pathway into the Halahatang Oilfield could be the most favorable targets for further oil exploration in this region.Li, M., Wei, G., Shi, W., Sun, Z., Li, H., Wang, X., Gao, Z., 2018. Distinct distribution patterns of ammonia-oxidizing archaea and bacteria in sediment and water column of the Yellow River estuary. Scientific Reports 8, Article 1584. oxidation is a critical process of estuarine nitrogen cycling involving ammonia-oxidizing archaea (AOA) and bacteria (AOB). However, the distribution patterns of ammonia-oxidizing microorganisms (AOMs) between different habitats in the same area remain unclear. The present study investigated the AOMs’ abundance and community compositions in both sediment and water habitats of the Yellow River estuary. Quantitative PCR (qPCR) revealed that AOA showed significant higher abundance than AOB both in sediment and water samples. AOA and AOB abundance distribution trends were consistent in sediment but distinct in water along the sampling sites. Clone library-based analyses showed that AOA sequences were affiliated with Nitrososphaera, Nitrosopumilus and Nitrosotalea clusters. Generally, Nitrososphaera was predominant in sediment, while Nitrosopumilus and Nitrosotalea dominated in water column. AOB sequences were classified into genera Nitrosospira and Nitrosomonas, and Nitrosospira dominated in both habitats. Principal coordinate analysis (PCoA) also indicated AOA community structures exhibited significant differences between two habitats, while AOB were not. Ammonium and carbon contents were the potential key factors to influence AOMs’ abundance and compositions in sediment, while no measured variables were determined to have major influences on communities in water habitat. These findings increase the understanding of the AOMs’ distribution patterns in estuarine ecosystems.Li, W., Zhu, Y.-M., Liu, Y., 2018. Gas evolution and isotopic fractionations during pyrolysis on coals of different ranks. International Journal of Coal Geology 188, 136-144. study was performed on 4 different coals of varied rank. Pyrolysis was conducted on coals of different ranks in gold capsules, with the yield and stable carbon isotopic values of selected gas components and liquid hydrocarbons separately measured to investigate the hydrocarbon generation chemistry, isotopic compositions, and kinetic parameters in coal. With increasing heating temperature, the methane concentrations and total gaseous hydrocarbons increase consistently with temperature. The liquid hydrocarbon concentrations first increase to maximum values and then decrease with temperature. Coals of higher ranks are more likely to primarily produce methane, while coal with low maturity is more likely to produce wet gases. The compositional differences of the four coals become similar at the late stage of the pyrolysis experiment, with a methane content >95%. All of the experiments show a similar isotope trend δ13C1?<?δ13C2?<?δ13C3 at the same temperature. The δ13C values of ethane and propane became less negative with increasing temperature for all four experiments. The gap between δ13C1 and δ13C2 is greater than that between δ13C2 and δ13C3. There is a linear relationship between ln(C1/C2) versus ln(C2/C3). When ln(C2/C3) increases sharply as ln(C1/C2) increases, the decomposition rates exceed the generation rates for C4?+5, C3, and C2 as secondary oil cracking occurs. At high temperatures, both parameters are larger. The activation energy distribution of 48–72?kcal/mol for Yilan coal is slightly higher than 55–66?kcal/mol for Xinjing coal, but significantly higher than the distribution of 46–61?kcal/mol for Qinan coal and 51–67?kcal/mol for Shitai coal.Li, X.-M., Sun, G.-X., Chen, S.-C., Fang, Z., Yuan, H.-Y., Shi, Q., Zhu, Y.-G., 2018. Molecular chemodiversity of dissolved organic matter in paddy soils. Environmental Science & Technology 52, 963-971. matter (OM), and dissolved organic matter (DOM), have a major influence upon biogeochemical processes; most significantly, the carbon cycle. To date, very few studies have examined the spatial heterogeneity of DOM in paddy soils. Thus, very little is known about the DOM molecular profiles and the key environmental factors that underpin DOM molecular chemodiversity in paddy soils. Here, Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry was applied to unambiguously resolve 11?361 molecular formulas in 16 paddy soils; thereby elucidating the molecular characteristics of paddy soil DOM. Soil pH, iron complexing index (Fep/FeR) and C/N ratio were established to be key factors controlling DOM profiles. Polycyclic aromatics (derived from combustion) and polyphenols (derived from plants) increased with increasing pH, while polyphenols molecules, pyrogenic aromatics, and carboxylic compounds decreased with increasing iron complexing index. Patterns in molecular profiles indicated DOM in paddy soils to become more recalcitrant at higher soil C/N ratio and higher pH. Furthermore, plant-derived polyphenols and pyrogenic DOM were retained favorably by iron and the chemodiversity of DOM in paddy soil increased with increasing soil C/N ratios. This study provides critical information about DOM characteristics at a molecular level and will inform better global management of soil carbon in paddy soil ecosystems.Li, Y., Han, S., Lu, Y., Zhang, J., 2018. Influence of asphaltene polarity on crystallization and gelation of waxy oils. Energy & Fuels 32, 1491-1497. report for the first time the results from a systematic investigation of how asphaltenes of different polarity affect crystallization and gelation of waxy oils. The more polar asphaltenes were found to be more aromatic in nature and more highly self-aggregated in the solvent. The presence of less polar asphaltenes in the waxy oil reduced the wax appearance temperature and wax precipitation to a greater degree compared to more polar asphaltenes, which was mainly attributed to the difference in the aggregation state of asphaltenes of different polarity. Reducing the polarity of asphaltenes present in the oil also resulted in a lower gelation temperature, lower storage modulus, and lower yield stress, which was probably because the less polar asphaltenes were more similar to wax on the molecular level and, thus, more readily interacting with wax. Notably, a 99% reduction in the yield stress was observed upon the addition of the least polar asphaltenes examined in the present work, in contrast to the 62% yield stress reduction upon the addition of the most polar asphaltenes. This observation may be of industrial significance because it suggests that the crude oil containing less polar asphaltenes may form a softer gel or deposit that is more easily broken or removed. Microscopic analysis showed that the wax crystals precipitated in the presence of less polar asphaltenes have a smaller aspect ratio.Li, Z., Lowry, G.V., Fan, J., Liu, F., Chen, J., 2018. High molecular weight components of natural organic matter preferentially adsorb onto nanoscale zero valent iron and magnetite. Science of The Total Environment 628–629, 177-185. zero valent iron particles (nano-Fe0) are attractive for in-situ groundwater remediation due to their high reactivity and ability to degrade many different classes of environmental contaminants. It is expected that adsorbed natural organic matter (NOM), which is heterogeneous and typically has a wide molecular weight (MW) distribution, will affect the reactivity and performance of nano-Fe0 as a remediation agent. However, the interaction of NOM with nano-Fe0 has not been well-studied. In this study, we used high performance size exclusion chromatography (HPSEC) to determine if there was preferential sorption of the high MW fraction of NOM onto nano-Fe0 that have a Fe0 core and a Fe-oxide shell (predominantly magnetite). Adsorption of two types of NOM, Suwannee River Humic Acid (SRHA) and Fulvic Acid (SRFA), to nano-Fe0 was compared to magnetite of similar size (nano-Fe3O4) to also assess the effect of the Fe0 core on adsorption of NOM. The results showed that the surface area normalized adsorbed mass (mg/m2) of both SRHA and SRFA onto nano-Fe0 is almost three times than that of nano-Fe3O4. This is attributed to a greater number of reactive sites on nano-Fe0 compared to nano-Fe3O4, and indicates that the surface properties of nano-Fe0 are different that nano-Fe3O4 despite the shell of magnetite on nano-Fe0. The sorption capacity of both SRHA and SRFA onto nano-Fe0 were similar. However, the intermediate sized MW fractions (2–6?kDa) of SRHA were preferentially adsorbed onto the nano-Fe0 surface, whereas the large MW fractions (>3.5?kDa) of SRFA were preferentially adsorbed. These results suggest that NOM interaction with nano-Fe0 are a function of the MW distribution of the NOM in the system studied and indicate that the MW distributions of NOM should be taken into consideration when predicting the fate and performance of nano-Fe0 in environmental remediation.Liang, B., Clarens, A.F., 2018. Interactions between stratigraphy and interfacial properties on flow and trapping in geologic carbon storage. Water Resources Research 54, 72-87.: Gas leakage from geologic carbon storage sites could undermine the long-term goal of reducing emissions to the atmosphere and negatively impact groundwater resources. Despite this, there remain uncertainties associated with the transport processes that would govern this leakage. These stem from the complex interaction between governing forces (e.g., gravitational, viscous, and capillary), the heterogeneous nature of the porous media, and the characteristic length scales of these leakage events, all of which impact the CO2 fluid flow processes. Here we assessed how sub-basin-scale horizons in porous media could impact the migration and trapping of a CO2 plume. A high-pressure column packed with two layers of sand with different properties (e.g., grain size and wettability) was used to create a low-contrast stratigraphic horizon. CO2 in supercritical or liquid phase was injected into the bottom of the column under various conditions (e.g., temperature, pressure, and capillary number) and the transport of the resulting plume was recorded using electrical resistivity. The results show that CO2 trapping was most strongly impacted by shifting the wettability balance to mixed-wet conditions, particularly for residual saturation. A 16% increase in the cosine of the contact angle for a mixed-wet sand resulted in nearly twice as much residual trapping. Permeability contrast, pressure, and temperature also impacted the residual saturation but to a lesser extent. Flow rate affected the dynamics of saturation profile development, but the effect is transient, suggesting that the other effects observed here could apply to a broad range of leakage conditions.Plain Language Summary: One strategy for reducing CO2 emissions to the atmosphere is to inject it deep into the ground where it will remain trapped beneath layers of rock. Even deep in the ground, CO2 is less dense filling the pore space than the water and so it will have a natural tendency to rise to the surface where it might return to the atmosphere. To better understand the governing transport processes, we carried out experiments to measure the way that CO2 moves through layered sands flooded with water at high pressures and temperatures. We found that several things could impact the rate at which CO2 became trapped beneath a contrasting layer of sand but the most important factor is wettability. Wettability describes the way in which two contacting liquids arrange themselves on a solid surface. A small change toward more CO2-wetting conditions resulted in a big change in the amount of CO2 that would stay trapped beneath a layer of sand. Such a finding could help us develop models to estimate leakage rate from the geologic carbon storage projects.Liang, Z., Chen, L., Alam, M.S., Zeraati Rezaei, S., Stark, C., Xu, H., Harrison, R.M., 2018. Comprehensive chemical characterization of lubricating oils used in modern vehicular engines utilizing GC?×?GC-TOFMS. Fuel 220, 792-799. number of major studies have demonstrated that the SVOC (Semi-volatile organic compounds) within engine emissions derive predominantly from unburned fuel and lubricants, and are a major contributor to primary atmospheric aerosol containing thousands of organic compounds. The GC?×?GC-ToF-MS (2 dimensional Gas Chromatography – Time of Flight – Mass Spectrometry) comprehensive analytical technique was utilized in this study, to resolve the complex mixtures and characterize the SVOC content in eight different commercial lubricants, including 5?W30 synthetic and semi-synthetic, mineral and base oil. In order to quantify the aliphatic isomers, which comprise the largest component of the lubricants, a TIC-M.Q./Mass (Total ion current ratio to the molar quantity/mass) method has been developed. The TIC intensity was observed to be proportional to the molar quantity of n-alkanes for carbon number <C25, while being linear to the mass response for these aliphatic compounds with carbon number >C25. Additionally, the TIC intensity of the alkyl-cyclohexanes under the identical retention indices were found to have an equivalent response to those of the n-alkanes, showing that the quantitative calibrations derived for the n-alkane series could be applied to estimate the concentrations of isomeric aliphatic compounds with similar molecular weight. Furthermore, a mesh method was introduced to group the alkane species (n-alkanes, branched alkanes and cyclic alkanes etc.), combining with the use of a soft EI (electron impact) ionization (14?eV) to retain the distinct identity of the isomers with less fragmentation, which allowed the TIC-M.Q./Mass methodology to integrate all the constitutional isomers present in the lubricating oil samples. By utilizing this methodology, compositions from different samples were comprehensively compared, leading to the following conclusions: 1) the synthetic and semi-synthetic oils contained a larger abundance of HMW (high molecular weight) aliphatic compounds (carbon number C24–C29), while those in the LMW (low molecular weight range, carbon number C18–C25) were predominant in the mineral and base oil; 2) cycloalkanes were predominant in the synthetic and semi-synthetic oils; whereas the branched alkanes were more prominent in the mineral and base oils; 3) for lubricants used for a short period, a slight increase of LMW compounds was observed, while the HMW compounds underwent a decrease, whereas, there was an overall mass reduction for all the aliphatic compounds detected in the oil samples used for six-months.Liao, D., Lu, B., 2018. An evaluation method of engineering sweet spots of shale gas reservoir development: A case study from the Jiaoshiba Gas Field, Sichuan Basin. Natural Gas Industry 38, 43-50. quantitative evaluation of engineering sweet spots in shale gas reservoir development provides important reference for forecast on difficulties and costs in such projects. In this paper, the Jiaoshiba Shale Gas Field in the Sichuan Basin was taken as an example to search for a high-precision quantitative engineering sweet spot evaluation method. Firstly, the effects of engineering sweet spot parameters (e.g. brittleness index, stress difference coefficient, shale content and fracture pressure) on fracturing sand volume and fluid volume were qualitatively analyzed. Then, a quantitative analysis was conducted by means of the correlation coefficient to determine principal engineering sweet spot parameters and the corresponding target evaluation indexes which characterize shale gas reservoir development. Finally, such shale gas engineering sweet spots were evaluated based on three models (i.e., single parameter model, radar area model and independence weight coefficient model) and the evaluation results were compared. The following research results were obtained. First, shale content, brittleness index, calcareous content and stress difference coefficient are the main engineering sweet spot parameters. Second, the multi-target evaluation problem, which occurs when the engineering sweep spot is characterized by using sand volume and fluid volume, can be avoided effectively by characterizing the engineering sweet spots by means of sand carrying ratio. Third, the evaluation precision of engineering sweet spots is the highest in the independence weight coefficient model, secondary in the radar area model and the lowest in the single parameter model. Field application effects in three fracturing wells also show that the quantitative evaluation result of engineering sweet spots in shale formations by the independence weight coefficient model is reliable. To sum up, it is appropriate to adopt the independence weight coefficient model to quantitatively evaluate the engineering sweet spots in shale gas reservoir development.Lin, X., Huang, R., Li, Y., Li, F., Wu, Y., Hutchins, D.A., Dai, M., Gao, K., 2018. Interactive network configuration maintains bacterioplankton community structure under elevated CO2 in a eutrophic coastal mesocosm experiment. Biogeosciences 15, 551-565. is increasing concern about the effects of ocean acidification on marine biogeochemical and ecological processes and the organisms that drive them, including marine bacteria. Here, we examine the effects of elevated CO2 on the bacterioplankton community during a mesocosm experiment using an artificial phytoplankton community in subtropical, eutrophic coastal waters of Xiamen, southern China. Through sequencing the bacterial 16S rRNA gene V3-V4 region, we found that the bacterioplankton community in this high-nutrient coastal environment was relatively resilient to changes in seawater carbonate chemistry. Based on comparative ecological network analysis, we found that elevated CO2 hardly altered the network structure of high-abundance bacterioplankton taxa but appeared to reassemble the community network of low abundance taxa. This led to relatively high resilience of the whole bacterioplankton community to the elevated CO2 level and associated chemical changes. We also observed that the Flavobacteria group, which plays an important role in the microbial carbon pump, showed higher relative abundance under the elevated CO2 condition during the early stage of the phytoplankton bloom in the mesocosms. Our results provide new insights into how elevated CO2 may influence bacterioplankton community structure.Lindeberg, M.R., Maselko, J., Heintz, R.A., Fugate, C.J., Holland, L., 2018. Conditions of persistent oil on beaches in Prince William Sound 26 years after the Exxon Valdez spill. Deep Sea Research Part II: Topical Studies in Oceanography 147, 9-19. March 24, 1989, the Exxon Valdez grounded on Bligh Reef in Prince William Sound, Alaska, spilling an estimated 10.8 million gallons of crude oil. Contrary to early projections, subsequent studies over several decades have shown subsurface oil persisting on impacted beaches. Here we present findings from a lingering oil survey conducted during the summer of 2015 at a small set of beaches in Prince William Sound known to have persistent subsurface Exxon Valdez oil. The objectives of the survey were to estimate how much oil remains at these sites, the oil composition, and oil retention rates compared to previous studies. Results from the survey found lingering oil was present at 8 of 9 sites that were revisited. Surveys revealed little evidence of change in oil area or mass over the last 14 years, nor has there been a change in the distribution of oiling intensities or their location on the beach. Detailed analysis of the oil indicated it has not weathered since 2001. Subsurface oils collected in 2015 have enriched concentrations of phenanthrenes and chrysenes relative to oil originating in the cargo hold indicating that buried oil has retained some toxic potential over the last two decades, but it is not currently bioavailable. Subsurface oil appears to be sequestered in sediments and protected from hydrological washing and low oxygen and nutrient levels inhibiting biodegradation. These findings are consistent with previous surveys and predictive geomorphic models suggesting the estimated 0.6% Exxon Valdez oil remaining is sequestered and not bioavailable unless disturbed and will likely persist in the environment on a decadal scale.Lipok, C., Hippler, J., Schmitz, O.J., 2018. A four dimensional separation method based on continuous heart-cutting gas chromatography with ion mobility and high resolution mass spectrometry. Journal of Chromatography A 1536, 50-57. two-dimensional GC (2D-GC) method was developed and coupled to an ion mobility-high resolution mass spectrometer, which enables the separation of complex samples in four dimensions (2D-GC, ion mobilility spectrometry and mass spectrometry). This approach works as a continuous multiheart-cutting GC-system (GC + GC), using a long modulation time of 20 s, which allows the complete transfer of most of the first dimension peaks to the second dimension column without fractionation, in comparison to comprehensive two-dimensional gas chromatography (GCxGC). Hence, each compound delivers only one peak in the second dimension, which simplifies the data handling even when ion mobility spectrometry as a third and mass spectrometry as a fourth dimension are introduced. The analysis of a plant extract from Calendula officinales shows the separation power of this four dimensional separation method. The introduction of ion mobility spectrometry provides an additional separation dimension and allows to determine collision cross sections (CCS) of the analytes as a further physicochemical constant supporting the identification. A CCS database with more than 800 standard substances including drug-like compounds and pesticides was used for CCS data base search in this work.Liu, H., Ren, J., Lyu, J., Lyu, X., Feng, Y., 2018. Hydrocarbon source rock evaluation of the Lower Cretaceous system in the Baibei Depression, Erlian Basin. Energy Exploration & Exploitation 36, 355-372. K1s, K1d, K1t, and K1a Formations are potential source rock intervals for hydrocarbon formation, all of which are part of the Lower Cretaceous system in the Baibei Depression in the Erlian Basin in China. However, no well has found oil flow because the hydrocarbon-generating potential of the source rocks has not been comprehensively evaluated. Based on organic geochemical and petrological analyses, all the source rocks possess highly variable total organic carbon and S1?+?S2 contents. Total organic carbon and S1?+?S2 contents indicate that the K1a2 Formation through the K1d1 Formation are source rocks that have fair to good generative potential and the K1d2 Formation through the K1s Formation are source rocks that have good to very good generative potential. The organic matter in the K1a2 Formation is dominated by Type I and II kerogen; thus, it is considered to be oil prone based on H/C versus O/C plots. Most of the analyzed samples were deposited in reducing environments and sourced from marine algae; thus, they are oil prone. However, only two source rock intervals were thermally mature with vitrinite reflectance values in the required range. Hydrocarbon-generating histories show that the K1t and K1a2 intervals began to generate hydrocarbons during the depositional period of the K1d2 and K1d3 Formations, respectively, and stopped generating hydrocarbons at the end of the depositional period of the late Cretaceous. Therefore, the main stage of hydrocarbon migration and accumulation was between the depositional period of the K1d2 and K1s Formations, and the critical moment was the depositional period of the late K1s Formation. The generation conversion efficiency reached approximately 55% in the K1a2 Formation and 18% in the K1t Formation at the end of the Cretaceous sedimentary stage. In general, the effective oil traps are those reservoirs that are near the active source rock in the generating sags in the Baibei Depression.Liu, H., Sang, S., Xue, J., Lan, T., Xu, H., Ren, B., Liu, S., 2018. Evolution and geochemical characteristics of gas phase fluid and its response to inter-well interference during multi-well drainage of coalbed methane. Journal of Petroleum Science and Engineering 162, 491-501. Fanzhuang block from the southern Qinshui basin was used as a monitoring area to determine the components, the methane carbon isotopes (δ13C1) and the methane hydrogen isotopes (δD) of the recovered coalbed methane (CBM) during the different production times. The spatial evolution characteristics of the CBM components, δ13C1 and δD and their response to inter-well interference during multi-well drainage in CBM production areas were analyzed visually. The results show that CBM components, δ13C1 and δD all fluctuated; the spatial distribution direction of CBM components, δ13C1 and δD also changed twice or more during sampling in the studied area. The fractionation of δD lags behind the fractionation of δ13C1. The spatial distribution of the CBM components is affected by the CBM components obtained from partial CBM wells; the spatial distribution of δ13C1 and δD of coalbed methane is affected by the fractionation of δ13C1 and δD from the produced CBM. The decrease in the CBM components and the δ13C1 and δD ratios reveals the effects of inter-well interference on the multi-well patterns. The variability in the spatial distribution direction of CBM components, δ13C1 and δD shows that inter-well interference may still be in an early stage or the degree of inter-well interference may be relatively weak. The incomplete consistency of the spatial evolution of CBM components, δ13C1 and δD is mainly related to the fractionation of CBM components and methane isotopes during drainage and the change in the CBM supply caused by the unstable fluid field under unbalanced inter-well interference. It was shown that inter-well interference during multi-well drainage increases and then begins to stabilize. The established geochemical response model and evaluation program of inter-well interference provide a method to determine the stage and the degree of inter-well interference in CBM production areas, not only in the southern Qinshui basin but also in other CBM basins with low permeability.Liu, J., Jiang, Y., Liu, X., Zhu, R., 2018. Natural gas migration and accumulation model and favorable exploration targets in Ordovician dolomite in Jingxi, Ordos Basin. Energy Exploration & Exploitation 36, 373-387. Ordovician dolomite reservoir in Ma55–Ma510 sub-members in Jingxi in Ordos Basin is a newly discovered field with multiple natural gas pools. The gas accumulation patterns of the reservoir are unclear. Considering the geological background, the genesis, migration, and accumulation of natural gas in Jingxi were studied systematically, and favorable exploration targets were predicted. Natural gas in Ma55–Ma510 sub-members is a mixture of Upper Paleozoic and Ordovician products. The Upper Paleozoic coaliferous gas was mainly expulsed downward through the hydrocarbon-providing window where the coal-bearing source rocks made contact with the dolomite reservoirs. The gas then migrated from west to east and accumulated under the condition of lithology variation. The Ordovician petroliferous gas mainly migrated from bottom to top through fractures and mixed with the coaliferous gas in Ma55–Ma510 sub-members. The natural gas reservoir formation model was summarized as the migration of gas over a short distance and partial charging into the dolomite reservoirs from the Late Triassic to Middle Jurassic, and the migration of gas over a long distance and massive charging into the dolomite reservoirs during the Late Cretaceous. Ma55 and Ma56 sub-members are the focus of further exploration, and petroliferous gas in Ma57–Ma510 sub-members deserves attention. The dolomite reservoirs of the hydrocarbon-providing windows and the east of these locations are the favorable exploration targets.Liu, L., De Kock, T., Wilkinson, J., Cnudde, V., Xiao, S., Buchmann, C., Uteau, D., Peth, S., Lorke, A., 2018. Methane bubble growth and migration in aquatic sediments observed by X-ray μCT. Environmental Science & Technology 52, 2007-2015. bubble formation and transport is an important component of biogeochemical carbon cycling in aquatic sediments. To improve understanding of how sediment mechanical properties influence bubble growth and transport in freshwater sediments, a 20-day laboratory incubation experiment using homogenized natural clay and sand was performed. Methane bubble development at high-resolution was characterized by μCT. Initially, capillary invasion by microbubbles (< 0.1 mm) dominated bubble formation, with continued gas production (4 d for clay; 8 d for sand), large bubbles formed by deforming the surrounding sediment, leading to enhanced of macropore connectivity in both sediments. Growth of large bubbles (> 1 mm) was possible in low shear yield strength sediments (< 100 Pa), where excess gas pressure was sufficient to displace the sediment. Lower within the sand, higher shear yield strength (> 360 Pa), resulted in a predominance of microbubbles where the required capillary entry pressure was low. Enhanced bubble migration, triggered by a controlled reduction in hydrostatic head, was observed throughout the clay column, while in sand mobile bubbles were restricted to the upper 6 cms. The observed macropore network was the dominant path for bubble movement and release in both sediments.Liu, Q., Jin, Z., Wang, X., Yi, J., Meng, Q., Wu, X., Gao, B., Nie, H., Zhu, D., 2018. Distinguishing kerogen and oil cracked shale gas using H, C-isotopic fractionation of alkane gases. Marine and Petroleum Geology 91, 350-362. formation mechanism of 23 shale gas samples from the Fuling shale gas field in the Upper Ordovician Wufeng (O3w) Formation-Lower Silurian Longmaxi (S1l) Formation marine shales was investigated based on the carbon and hydrogen isotopes of methane, ethane, and propane. Fuling shale gas is mainly composed of alkane gases, and has a dryness coefficient, C1/C1-3, of 0.992–0.993. The reversed carbon isotopic trend where δ13C1?>?δ13C2 is a typical characteristic indicating mixing of kerogen cracked gas and crude oil cracked gas. The empirical correlations between ln (C1/C2) vs. ln (C2/C3) and ln (C1/C2) vs. δ13C of alkane gases at different thermal maturity levels were used to distinguish kerogen cracked gas from crude oil cracked gas. Five stages of kerogen cracking and crude oil cracking were identified with a wide range of thermal maturities (vitrinite reflectance %Ro): 1) %Ro?<?0.8: shale gas showed a normal isotopic trend (δ13C1?<?δ13C2) and was dominated by primary kerogen cracking; 2) %Ro of 0.8–1.5: primary kerogen cracking ended, and crude oil cracking was initiated, which is associated with a normal isotopic trend of methane and ethane (δ13C1?<?δ13C2); 3) %Ro of 1.5–1.8: the gas is the mixture of gases from both late kerogen cracking and oil cracking, with an initially reversed carbon isotopic trend of δ13C1?>?δ13C2; 4) %Ro of 1.8–2.5: residual kerogen cracking proceeded to generate CH4, and light oil cracking generated heavier gaseous hydrocarbons, with a completely reversed carbon isotopic trend of alkane gases (δ13C1?>?δ13C2?>?δ13C3); 5) %Ro?>?2.5: further cracking of heavier gaseous hydrocarbons generated CH4.Liu, S., Wang, Z., Zhang, L., 2018. Experimental study on the cracking process of layered shale using X-ray microCT. Energy Exploration & Exploitation 36, 297-313. cracking process in Longmaxi formation shale was experimentally studied during uniaxial compressive loading. Both the evolution of the three-dimensional fracture network and the micromechanics of failure in the layered shale were examined as a function of the inclination angle of the bedding plane. To visualize the cracking process, the test devices presented here used an industrial X-ray CT scanner that enabled scanning during the uniaxial compressive loading. Scanning electron microscopy and environmental scanning electron microscopy imaging techniques were used to observe the microscopic characteristics of fractured surfaces of failed specimens. The combination of these observations clearly illustrated the micromechanics of the failure process in the anisotropic shale. The experimental results suggest that the cracking process could be divided into two stages under uniaxial loading, and the microstructures and bedding planes of the shale played an important role in the cracking process of layered shale. In the first stage of deformation, the cracking mainly occurred as smaller microcracks (such as intergranular, microcracks), and the propagation of the newly formed microcracks was controlled by the bedding plane of the shale specimen. The microscopic imaging study showed that the microscopic damage was mainly dominated by microtensile fractures under uniaxial compression. In the second stage, with the increase in loading, the extensive development and coalescence of the microcracks led to the formation of complex fracture networks. The complexity of the fracture networks was related to the microstructure of the sample. The coalescence of the microcracks could be divided into three levels in the spatial scale, and the coalescence patterns included both tensile and shear patterns.Liu, Y., Tian, Y., Yang, C., Xiao, D., Liao, Q., Shen, C., Fan, Y., Tang, P., Pu, X., Jiang, W., 2017. Hydrocarbon phase limit and conversion process in the deep formation from Qikou Sag of Bohai Bay rift lacustrine basin, China. Journal of Natural Gas Geoscience 2, 229-238. is an important research direction for the prediction of hydrocarbon phase in the reservoir during the deep exploration of rift basins in eastern China. The typical lacustrine crude oil of Shahejie Formation in Qikou Sag was used for oil cracking to gas simulation experiment by the gold tube in this paper. Then, the kinetic parameters obtained from the experimental data were studied during the cracking reactions and the hydrocarbon phase conversion process under geological conditions. The results showed that the activation energy of the oil cracking to gas from the BH-28 lacustrine crude oil ranged from 250 kJ/mol to 270 kJ/mol with an average of EO = 255.47 kJ/mol, and the frequency factor was about A = 1014 s?1. It is higher than that of typical marine oil EO = 246.97 kJ/mol. Using these kinetic parameters, the simulated cracking process of the lacustrine oil of Shahejie Formation was far different from that of marine oil from western China under the same geological heating rate (3 °C/Ma). And the simulated oil cracking degree in Well Niudong-1 is 73.9%, almost the same with the conversion cracking degree (60%–75%) by concentrations of 3,4-dimethyldiamantane. The kinetics of oil cracking gas could be used to investigate the oil cracking degree easily, then to get the theoretical separate oil phase depth limit. By using this model, oil in Qikou Sag, as a theoretical separate phase destruction, occurs above 5700 m depth limit (RO is about 2.0%, reservoir temperature = 209 °C, with cracking transition C of 62.5%), and condensate gas destruction occurs above 6700 m depth limit (RO is about 3.2%, reservoir temperature = 240 °C, with C to 99%) under the geological conditions from Qikou Sag. Actually, the hydrocarbon phase is affected by many factors. For example, migration and changes of temperature and pressure conditions have great influence on phase conversion behavior. The injection of gas, originated from kerogen cracking gas and oil cracking gas in deeper, could increase GOR and the real separate phase depth would reduce.Liu, Y., Wang, C., 2018. Determination of the absolute adsorption isotherms of CH4 on shale with low-field nuclear magnetic resonance. Energy & Fuels 32, 1406-1415. of the absolute adsorption behavior of CH4 on shale is critically important in estimating shale gas storage in shale gas reservoirs. In this work, two approaches are applied to obtain the absolute adsorption isotherms of CH4 on shale samples. In the first approach, we first measure the excess adsorption isotherms of CH4 on two shale samples at the temperature of 298.15 K and pressures up to 12.0 MPa. Then, grand canonical Monte Carlo (GCMC) simulations are used to calculate the adsorption-phase density; such density values are consequently applied to calibrate the measured excess adsorption and obtain the accurate absolute adsorption isotherms. As for the second approach, we apply the low-field nuclear magnetic resonance (NMR) method to describe the absolute adsorption of CH4 on shale. A NMR-based setup is designed to measure the T2 spectrum distributions in shale samples by injecting CH4 into dry shale samples. The injecting pressure is set up to 12.0 MPa, which is similar to the conditions used in the excess adsorption measurements. On the basis of the measured T2 spectrum and the injected molar amount of CH4, the adsorbed molar quantity of CH4 can be assessed on the shale samples under specific conditions. We then compare the absolute adsorption isotherms obtained from both methods and evaluate the capability of the NMR approach in determining the absolute adsorption of CH4 on shale. With GCMC simulations, we find that the calculated adsorption-phase density strongly correlates with the system pressure and temperature. By taking into consideration the adsorption-phase density, the absolute adsorption isotherm is always higher than the measured excess adsorption curves; that is, the measured excess adsorption underestimates the actual adsorption capacity on shale. On the basis of the comparison results, the adsorption isotherms obtained from the NMR method have a good agreement with the corresponding absolute adsorption isotherms after calibrating with the adsorption-phase density; it indicates that the low-field NMR-based setup is a good tool in obtaining the absolute adsorption isotherms of CH4 on shale.Lovecchio, E., Gruber, N., Münnich, M., 2018. Mesoscale contribution to the long-range offshore transport of organic carbon from the Canary Upwelling System to the open North Atlantic. Biogeosciences Discussions 2018, 1-47. studies in upwelling regions have suggested that mesoscale structures, such as eddies and filaments, contribute substantially to the long-range transport of the organic carbon from the nearshore region of production to the offshore region of remineralization. Yet this has not been demonstrated in a quantitative manner for the entire Canary Upwelling System (CanUS). Here, we fill this gap using the Regional Oceanic Modeling System (ROMS) coupled to a Nutrient, Phytoplankton, Zooplankton, and Detritus (NPZD) ecosystem model. We run climatological simulations on an Atlantic telescopic grid with an eddy-resolving resolution in the CanUS. Using both a Reynolds flux decomposition and structure-identification algorithms, we quantify and characterize the organic carbon fluxes driven by filaments and eddies within the upper 100?m and put them in relationship to the total offshore transport. Our analyses reveal that both coastal filaments and eddies enhance the offshore flux of organic carbon, but that their contribution is very different. Upwelling filaments, with their high speeds and high organic carbon concentrations, transport this carbon offshore in a very intense, but coastally-confined, manner, contributing nearly 80?% to the total flux at 100?km offshore distance. The filament contribution tapers off quickly to near zero values at 1000?km distance, leading to a strong offshore flux divergence that is the main lateral source of organic carbon in the first 500?km offshore. Some of this divergence is also due to the filaments inducing a substantial vertical subduction of the organic carbon below 100?m. Owing to the temporal persistence and spatial recurrence of filaments, the filament transport largely constitutes a time-mean flux and only to a limited degree represents a turbulent flux. At distances beyond 500?km from the coast, eddies dominate the mesoscale offshore transport. Although their contribution represents only 20?% of the total offshore flux and of its divergence, eddies, especially cyclones, transport organic carbon offshore to distances as great as 2000?km from the coast. The eddy transport largely represents a turbulent flux, but striations in this transport highlight the existence of typical formation spots and recurrent offshore propagation pathways. While they propagate slowly, eddies are an important organic carbon reservoir for the open waters, since they contain on average a third of the offshore organic carbon, two third of which is found in cyclones. Our analysis confirms the importance of mesoscale processes for the offshore organic carbon transport and the fueling of the heterotrophic activity in the eastern subtropical North Atlantic, and highlights the need to consider the mesoscale flux in order to fully account for the three-dimensionality of the marine biological pump.Lu, L.-M., Mao, L.-F., Yang, T., Ye, J.-F., Liu, B., Li, H.-L., Sun, M., Miller, J.T., Mathews, S., Hu, H.-H., Niu, Y.-T., Peng, D.-X., Chen, Y.-H., Smith, S.A., Chen, M., Xiang, K.-L., Le, C.-T., Dang, V.-C., Lu, A.-M., Soltis, P.S., Soltis, D.E., Li, J.-H., Chen, Z.-D., 2018. Evolutionary history of the angiosperm flora of China. Nature 554, 234-238. species diversity may result from recent rapid speciation in a ‘cradle’ and/or the gradual accumulation and preservation of species over time in a ‘museum. China harbours nearly 10% of angiosperm species worldwide and has long been considered as both a museum, owing to the presence of many species with hypothesized ancient origins, and a cradle, as many lineages have originated as recent topographic changes and climatic shifts—such as the formation of the Qinghai–Tibetan Plateau and the development of the monsoon—provided new habitats that promoted remarkable radiation. However, no detailed phylogenetic study has addressed when and how the major components of the Chinese angiosperm flora assembled to form the present-day vegetation. Here we investigate the spatio-temporal divergence patterns of the Chinese flora using a dated phylogeny of 92% of the angiosperm genera for the region, a nearly complete species-level tree comprising 26,978 species and detailed spatial distribution data. We found that 66% of the angiosperm genera in China did not originate until early in the Miocene epoch (23 million years ago (Mya)). The flora of eastern China bears a signature of older divergence (mean divergence times of 22.04–25.39 Mya), phylogenetic overdispersion (spatial co-occurrence of distant relatives) and higher phylogenetic diversity. In western China, the flora shows more recent divergence (mean divergence times of 15.29–18.86 Mya), pronounced phylogenetic clustering (co-occurrence of close relatives) and lower phylogenetic diversity. Analyses of species-level phylogenetic diversity using simulated branch lengths yielded results similar to genus-level patterns. Our analyses indicate that eastern China represents a floristic museum, and western China an evolutionary cradle, for herbaceous genera; eastern China has served as both a museum and a cradle for woody genera. These results identify areas of high species richness and phylogenetic diversity, and provide a foundation on which to build conservation efforts in China.Lueders-Dumont, J.A., Wang, X.T., Jensen, O.P., Sigman, D.M., Ward, B.B., 2018. Nitrogen isotopic analysis of carbonate-bound organic matter in modern and fossil fish otoliths. Geochimica et Cosmochimica Acta 224, 200-222. nitrogen isotopic composition (δ15N) of otolith-bound organic matter (OM) is a potential source of information on dietary history of bony fishes. In contrast to the δ15N of white muscle tissue, the most commonly used tissue for ecological studies, the δ15N of otolith-bound OM (δ15Noto) provides a record of whole life history. More importantly, δ15Noto can be measured in contexts where tissue is not available, for example, in otolith archives and sedimentary deposits. The utility and robustness of otolith δ15N analysis was heretofore limited by the low N content of otoliths, which precluded the routine measurement of individual otoliths as well as the thorough cleaning of otolith material prior to analysis. Here, we introduce a new method based on oxidation to nitrate followed by bacterial conversion to N2O. The method requires 200-fold less N compared to traditional combustion approaches, allowing for thorough pre-cleaning and replicated analysis of individual otoliths of nearly any size. Long term precision of δ15Noto is 0.3‰. Using an internal standard of Atlantic cod (Gadus morhua) otoliths, we examine the parameters of the oxidative cleaning step with regard to oxidant (potassium persulfate and sodium hypochlorite), temperature, and time. We also report initial results that verify the usefulness of δ15Noto for ecological studies. For three salmonid species, left and right otoliths from the same fish are indistinguishable. We find that the δ15Noto of pink salmon (Oncorhynchus gorbuscha) is related to the size of the fish for this species. We find that intra-cohort δ15Noto standard deviation for wild pink salmon, farmed brown trout (Salmo trutta), and farmed rainbow trout (Oncorhynchus mykiss) are all 0.4‰ or less, suggesting that δ15Noto will be valuable for population-level studies. Lastly, our protocol yields reproducible data for both δ15Noto and otolith N content in 17th century Atlantic cod otoliths. We find that 17th century cod are approximately 2 ‰ higher than modern cod, arguably consistent with either the larger size of the otoliths (and thus inferred for the fish) or with changes in baseline (primary producer) δ15N in the modern coastal ocean compared to the past. All told, the results of this study bode well for the utility of otolith-bound δ15N for investigating the environment and ecology of modern and past fish.Lüning, S., Ga?ka, M., Danladi, I.B., Adagunodo, T.A., Vahrenholt, F., 2018. Hydroclimate in Africa during the Medieval Climate Anomaly. Palaeogeography, Palaeoclimatology, Palaeoecology 495, 309-322. Medieval Climate Anomaly (MCA) is a recognized period of distinct pre-industrial climate change, with a core period of 1000–1200?CE. The field of palaeoclimatology has made major progress over the past 15?years during which a great number of high- and medium-resolution case studies were published, reconstructing climate change of the past millennia. In many parts of the world, regional data coverage has now reached a point which allows compiling palaeoclimate maps for well-defined time intervals. Here we present hydroclimatic trend maps for the MCA in Africa based on 99 published study locations. Key hydroclimatic proxy curves are visualized and compared in a series of 16 correlation panels. Proxy types are described and possible issues discussed. Based on the combined MCA dataset, temporal and spatial trends are interpreted and mapped out. Three areas have been identified in Africa in which rainfall seems to have increased during the MCA, namely Tunisia, western Sahel and the majority of southern Africa. At the same time, a reduction in precipitation occurred in the rest of Africa, comprising of NW and NE Africa, West Africa, Eastern Africa and the Winter Rainfall Zone of South Africa. MCA hydroclimate change in Africa appears to have been associated with characteristic phases of ocean cycles, as also supported by modern climate observations. Aridity in Morocco typically coincides with the positive phase of the North Atlantic Oscillation (NAO), whilst increased rainfall in the western Sahel is often coupled to the positive phase of the Atlantic Multidecadal Oscillation (AMO). Reduction in rainfall in the region Gulf of Aden/southern Red Sea to Eastern Africa could be linked to a negative Indian Ocean Dipole (IOD) or a derived long-term equivalent Indian Ocean cycle parameter. The Intertropical Convergence Zone (ITCZ) appears to have been shifted pole-wards during the MCA, for both the January and July positions. MCA hydroclimate mapping revealed major data gaps in the Sahara, South Sudan, Somalia, Central African Republic, Democratic Republic of Congo, Angola, northern Mozambique, Zambia and Zimbabwe. Special efforts are needed to fill these gaps, e.g. through a dedicated structured research program in which new multiproxy datasets are created, based on the learnings from previous African MCA studies.Luong, T.M., Ponamoreva, O.N., Nechaeva, I.A., Petrikov, K.V., Delegan, Y.A., Surin, A.K., Linklater, D., Filonov, A.E., 2018. Characterization of biosurfactants produced by the oil-degrading bacterium Rhodococcus erythropolis S67 at low temperature. World Journal of Microbiology and Biotechnology 34, 20. of trehalolipid biosurfactants by Rhodococcus erythropolis S67 depending on the growth temperature was studied. R. erythropolis S67 produced glycolipid biosurfactants such as 2,3,4-succinoyl-octanoyl-decanoyl-2′-decanoyl trehalose and 2,3,4-succinoyl-dioctanoyl-2′-decanoyl trehalose during the growth in n-hexadecane medium at 26 and 10?°C, despite the different aggregate state of the hydrophobic substrate at low temperature. The surface tension of culture medium was found being reduced from 72 to 27 and 45?mN?m?1, respectively. Production of trehalolipid biosurfactants by R. erythropolis S67 at low temperature could be useful for the biodegradation of petroleum hydrocarbons at low temperatures by enhancing the bioremediation performance in cold regions.Luppo, T., López de Luchi, M.G., Rapalini, A.E., Martínez Dopico, C.I., Fanning, C.M., 2018. Geochronologic evidence of a large magmatic province in northern Patagonia encompassing the Permian-Triassic boundary. Journal of South American Earth Sciences 82, 346-355. Los Menucos Complex (northern Patagonia) consists of ～6?km thick succession of acidic and intermediate volcanic and pyroclastic products, which has been traditionally assigned to the Middle/Late Triassic. New U/Pb (SHRIMP) zircon crystallization ages of 257?±?2 Ma at the base, 252?±?2 Ma at an intermediate level and 248?±?2 Ma near the top of the sequence, indicate that this volcanic event took place in about 10 Ma around the Permian-Triassic boundary. This volcanism can now be considered as the effusive terms of the neighboring and coeval La Esperanza Plutono-Volcanic Complex. This indicates that the climax of activity of a large magmatic province in northern Patagonia was coetaneous with the end-Permian mass extinctions. Likely correlation of La Esperanza- Los Menucos magmatic province with similar volcanic and plutonic rocks across other areas of northern Patagonia suggest a much larger extension than previously envisaged for this event. Its age, large volume and explosive nature suggest that the previously ignored potential role that this volcanism might have played in climatic deterioration around the Permian-Triassic boundary should be investigated.Lyu, C., Ning, Z., Wang, Q., Chen, M., 2018. Application of NMR T2 to pore size distribution and movable fluid distribution in tight sandstones. Energy & Fuels 32, 1395-1405. paper explores the applicability of nuclear magnetic resonance (NMR) technology on pore size distribution (PSD) and movable fluid distribution (MFD) in tight sandstones. Centrifugation experiments and NMR tests are performed on saturated samples. The fluid changes in pores corresponding with three different types of NMR T2 distribution after each centrifugation is then analyzed. In addition, a new method to determine the conversion factor from NMR T2 distribution to PSD is developed. In comparison with the PSD obtained by mercury intrusion porosimetry, the new method is more suitable for PSD calculation in tight sandstones. Afterward, the optimum centrifugal force to determine the threshold radius for fluid flow is obtained. On the basis of this, we analyze MFD in tight formation. Through study, the following results are arrived at: patterns of NMR T2 distributions of outcrop and subsurface cores at water saturation condition can be classified into three types (I, II, and III). Among which, type I and type II show a better pore connectivity than type III with NMR T2 distribution of a higher movable peak and a lower immovable peak. The optimum centrifugal force for the Chang 6 tight formation to determine movable fluid is 418 psi and pores show no obvious difference with throats when radii are less than 0.05 μm. Movable fluids are mostly controlled by throats with radii smaller than 1 μm, especially throats with radii between 0.3 and 1 μm. Movable fluids are mostly stored in pores around the movable peak of bimodal NMR T2 distribution with radii ranging from 10 to 100 μm. These pores are residual interparticle pores and dissolution pores. The sets of experiments and the new method presented in this paper are proved effective in quantitively describing PSD and also qualitatively evaluating pore throat connectivity in tight sandstones. Petrophysical characterization by NMR technique provides an effective approach to better understand pore throat structures and storage capacity of tight oil reservoirs.Lyu, X., Liu, H., Pang, Z., Sun, Z., 2018. Visualized study of thermochemistry assisted steam flooding to improve oil recovery in heavy oil reservoir with glass micromodels. Fuel 218, 118-126. channeling, one serious problem in the process of steam flooding in heavy oil reservoir, decreases the sweep efficiency of steam to cause a lower oil recovery. Viscosity reducer and nitrogen foam, two effective methods to improve oil recovery with different mechanism, present a satisfactory result after steam flooding. In this article, a 2D visualized device was introduced to investigate the synergistic development effect of two different chemical additives and intuitively study their flowing characteristic in porous media, as well as macroscopic and microscopic mechanism of improving heavy oil recovery by chemical additives after steam flooding. The results showed that the fingering phenomenon was generated obviously in the process of steam flooding, which restricted the swept area of steam. Due to decreasing oil-water interface tension, O/W emulsion with lower viscosity was formed to enhance the oil flow capacity and polish up the displacement efficiency of steam after injecting viscosity reducer. And the synergistic effect of viscosity reducer & foaming agent was more conductive to improve displacement efficiency of steam, with 4.3% of oil recovery higher than purely viscosity reducer assisting steam flooding in this process. Microscopic results indicated that thermal foams can be trapped in the porous media to improve injection profile effectively and displace the residual oil caused by steam flooding. The ultimate oil recovery of synergistic development is 65.6%, 11.0% higher than one additive (viscosity reducer). This article can provide reference for the study of thermochemistry assisted steam flooding in heavy oil reservoir.Ma, A., Jin, Z., Zhu, C., Bai, Z., 2017. Cracking and thermal maturity of Ordovician oils from Tahe Oilfield, Tarim Basin, NW China. Journal of Natural Gas Geoscience 2, 239-252. thermal maturity of the Ordovician oils from the Tahe oilfield of Tarim Basin, NW China was assessed through various maturity parameters, such as biomarkers, aromatic parameters, and diamondoid parameters. Both Ts/(Ts+Tm) and C29Ts/(C29H+C29Ts) values indicate that the maturity of oils has not reached the condensates stage, which is consistent with the maturity obtained by MPI1. However, the diamondoid maturity suggests that the oil maturity ranges 1.1%–1.6% Ro, which is apparently higher than that of the maturity obtained by the biomarker and MPI1. This discrepancy in maturity may indicate that the Ordovician reservoir has multiple filling history. The 4-MD+3-MD concentration of oils disperses and increases slowly when the Ts/(Ts+Tm) value is lower than 0.55. Meanwhile, the value increases rapidly when the Ts/(Ts+Tm) value is higher than 0.55. It is proposed that the diamondoid baseline is about 15 μg/goil for marine oils in the Tahe oilfield based on the diamondoid concentration of marine oils from reservoirs of various age. The concentration of 4-MD+3-MD of most Ordovician oils generally ranges from 4.5 to 35 μg/goil, suggesting that the degree of oil-cracking is lower than 50% and the deep Ordovician have potential of oil exploration. The distribution of the concentration of 4-MD+3-MD is characterized by being high in the east and south, low in the west and north, proposing that the two migration pathways exit in the oilfield, which are from east to west and from south to north, respectively. The migration directions are consistent with the results obtained from the oil density and the maturity parameters such as Ts/(Ts+Tm). Thus, suggesting the concentration of 4-MD+3-MD can be used as migration index in oilfield scale.Macgregor, D., 2018. History of the development of Permian–Cretaceous rifts in East Africa: a series of interpreted maps through time. Petroleum Geoscience 24, 8-20. Africa represents the most rifted portion of crust on the planet, having been subjected to numerous phases of extension from Permian to Recent times. The first rifting phase commences in the Permian as the ‘Karoo’ set of narrow half-graben, many formed by lateral shear. Peak rifting appears to be of Middle Permian age for rifts south of Tanzania. In Kenya, Ethiopia and Somalia, this rift population merges into a set of rifts with peak rifting of earliest Triassic age.A further phase of rifting is seen in the Toarcian–Aalenian. Many of these overlie Permo-Triassic rifts but others are displaced towards what will become the continental margin. Three unrelated populations of Late Jurassic–Early Cretaceous rifts are observed, including those in Somalia, a series of pull-apart basins on the Davie Ridge and a poorly documented set in southern Mozambique. The Anza Rift, with peak rifting in the Late Cretaceous associated with the building of rift shoulders kilometres in height, is proposed here to be an isolated plume-derived rift.Evaluation of the petroleum potential associated with these rifts relies on an accurate assessment of each in terms of their age and affinity to well-documented systems.Macgregor, D., Argent, J., Sansom, P., 2018. Introduction to the thematic set: Tectonics and petroleum systems of East Africa. Petroleum Geoscience 24, 3-7. paper provides an overview of a series of papers to be published within two issues of Petroleum Geoscience in 2018 expressing the theme ‘tectonics and petroleum systems of East Africa’. These papers partly result from the Geological Society of London's Petroleum Group conference in April 2016 on ‘East Africa; From Research to Reserves'. The theme of this conference highlighted the advances that have been made since a previous East Africa conference as a result of the recent major exploration efforts. This issue (February 2018) concentrates on the regional tectonics and include overviews of our current understanding of Permian to Mesozoic rifting (Macgregor), Tertiary rifting (Purcell), the plate tectonic model (Reeves), and of the development of the East African margin (Davison & Steel). The August 2018 issue is planned to include more basin and regional specific papers on the Kenyan rift system, offshore Somalia, offshore Tanzania and offshore Mozambique.This first series of papers provides a comprehensive summary of our developing state of knowledge of regional tectonics across East Africa and its influence on petroleum systems. While there were a number of oral papers presented at this and subsequent conferences which provided greater detail on the numerous petroleum discoveries across the region that have been made this century, it would appear that this compilation was too early for operators to release such data in writing and as yet, we are still lacking many peer reviewed papers on East African petroleum systems. Table 1 presents a brief summary of our knowledge of the most significant discoveries in each basin which, in terms of reserve additions, make East Africa the most globally successful region in this century for frontier conventional exploration. In keeping with the tectonic diversity and complexity of the region, these individual fields have little in common with each other, though there is a general theme of complex trapping styles, with the traditional four-way-dip closures, that have comprised the trap types of most of the world‘s giant fields, not represented at all on this list. There is also an apparent relationship between the regions of success and those of active Neogene subsidence and likely hydrocarbon generation. Many of these petroleum systems, particularly those within or close to Neogene rifts (including the Kerimbas Graben of the Rovuma Basin) may be dynamic petroleum systems. Madhavaraju, J., Lee, Y.I., Scott, R.W., González-León, C.M., Jenkyns, H.C., Saucedo-Samaniego, J.C., Ramasamy, S., 2018. High-resolution carbonate isotopic study of the Mural Formation (Cerro Pimas section), Sonora, México: Implications for early Albian oceanic anoxic events. Journal of South American Earth Sciences 82, 329-345. 420-m thick stratigraphic section of the Mural Formation that is exposed in the Cerro Pimas area of northern Sonora, Mexico, is composed of limestone lithofacies ranging from bioclastic wackestone to boundstone, whose biota is characterized by low diversity. Prominent age-diagnostic fossils are benthic foraminifera and long-ranging calcareous algae that indicate the Aptian/Albian boundary is close to the base of the Los Coyotes Member. The carbonates of this formation have negative to positive δ13C values (?4.63 to +2.6‰) and highly depleted δ18O values that range from ?12.74 to ?8.34‰. The absence of correlation between δ13C and δ18O values supports a primary marine origin for the δ13C values of these limestones.The carbon-isotopic curve of the Cerro Pimas stratigraphic section has well-defined δ13C segments (C8 – C15) that compare with published curves of similar age. In the lower part of the early Albian Los Coyotes Member, the presence of OAE 1b is indicated by an increase followed by a decrease in δ13C values, suggesting correlation with the Kilian Event. The middle part of the Los Coyotes Member has a significant negative carbon-isotope excursion correlated with the globally recognizable early Albian Paquier event. Moreover, another significant negative carbon-isotope shift is observed in the upper part of the Los Coyotes Member, which can be correlated with the Leenhardt Event. The occurrence of the Kilian, Paquier and Leenhardt Events (OAE 1b cluster) in the Cerro Pimas stratigraphy confirms the global nature of these early Albian disturbances of the carbon cycle.Magagna, F., Liberto, E., Reichenbach, S.E., Tao, Q., Carretta, A., Cobelli, L., Giardina, M., Bicchi, C., Cordero, C., 2018. Advanced fingerprinting of high-quality cocoa: Challenges in transferring methods from thermal to differential-flow modulated comprehensive two dimensional gas chromatography. Journal of Chromatography A 1536, 122-136. possibility to transfer methods from thermal to differential-flow modulated comprehensive two-dimensional gas chromatographic (GC × GC) platforms opens interesting perspectives for routine analysis of complex samples. Flow modulated platforms avoid the use of cryogenics, thereby simplifying laboratory operations and analyst supervision during intensive analytical sessions.This study evaluates the feasibility of transferring a fingerprinting method capable of classifying and discriminating cocoa samples based on the volatiles fraction composition according to their origin and processing steps. Previously developed principles of GC × GC method translation are applied to an original fingerprinting method, developed for a loop-type thermal modulated GC × GC–MS system, to engineer a method for a reverse-injection differential flow modulated platform (GC × 2GC–MS/FID) with a dual-parallel secondary column and dual detection. Effective method translation preserves analytes elution order, 1D resolution, and 2D pattern coherence.The experimental results confirm the feasibility of translating fingerprinting method conditions while preserving the informative power of 2D peak patterns for sample classification and discrimination. Correct translation enables effective transfer of metadata (e.g., compound names and MS fragmentation patterns) by automatic template transformation and matching from the original/reference method to its translated counterpart. Although the adoption of a narrow bore (i.e. 0.1 mm dc) column in the first-dimension enabled operation under close-to-optimal conditions with the differential-flow modulation platform, due to the dual-parallel columns in the second-dimension, it resulted in lower overall method sensitivity. Nevertheless, fingerprinting accuracy was preserved and most of the key-aroma compounds and technological markers were effectively mapped, thus limiting the loss of fingerprinting information.Magnabosco, C., Moore, K.R., Wolfe, J.M., Fournier, G.P., 2018. Dating phototrophic microbial lineages with reticulate gene histories. Geobiology 16, 179-189. bacteria are among the most biogeochemically significant organisms on Earth and are physiologically related through the use of reaction centers to collect photons for energy metabolism. However, the major phototrophic lineages are not closely related to one another in bacterial phylogeny, and the origins of their respective photosynthetic machinery remain obscured by time and low sequence similarity. To better understand the co-evolution of Cyanobacteria and other ancient anoxygenic phototrophic lineages with respect to geologic time, we designed and implemented a variety of molecular clocks that use horizontal gene transfer (HGT) as additional, relative constraints. These HGT constraints improve the precision of phototroph divergence date estimates and indicate that stem green non-sulfur bacteria are likely the oldest phototrophic lineage. Concurrently, crown Cyanobacteria age estimates ranged from 2.2?Ga to 2.7?Ga, with stem Cyanobacteria diverging ~2.8?Ga. These estimates provide a several hundred Ma window for oxygenic photosynthesis to evolve prior to the Great Oxidation Event (GOE) ~2.3?Ga. In all models, crown green sulfur bacteria diversify after the loss of the banded iron formations from the sedimentary record (~1.8?Ga) and may indicate the expansion of the lineage into a new ecological niche following the GOE. Our date estimates also provide a timeline to investigate the temporal feasibility of different photosystem HGT events between phototrophic lineages. Using this approach, we infer that stem Cyanobacteria are unlikely to be the recipient of an HGT of photosystem I proteins from green sulfur bacteria but could still have been either the HGT donor or the recipient of photosystem II proteins with green non-sulfur bacteria, prior to the GOE. Together, these results indicate that HGT-constrained molecular clocks are useful tools for the evaluation of various geological and evolutionary hypotheses, using the evolutionary histories of both genes and organismal lineages.Makou, M., Eglinton, T., McIntyre, C., Montlu?on, D., Antheaume, I., Grossi, V., 2018. Plant wax n-alkane and n-alkanoic acid signatures overprinted by microbial contributions and old carbon in meromictic lake sediments. Geophysical Research Letters 45, 1049-1057. n-alkanes and n-alkanoic acids are commonly used as biomarkers in paleoenvironmental reconstruction, yet any individual homologue may originate from multiple biological sources. Here we improve source and age controls for these compounds in meromictic systems by measuring the radiocarbon (14C) ages of specific homologues preserved in twentieth century Lake Pavin (France) sediments. In contrast to many studies, 14C ages generally decreased with increasing carbon chain length, from 7.3 to 2.6 ka for the C14-C30 n-alkanoic acids and from 9.2 to 0.3 ka for the C21-C33 n-alkanes. Given a known hard water effect, these values suggest that aquatic microbial sources predominate and contributed to most of the homologues measured. Only the longest chain n-alkanes exclusively represent inputs of higher plant waxes, which were previously sequestered in soils over centennial to millennial timescales prior to transport and deposition. These findings suggest that biomarker source and age should be carefully established for lacustrine settings.Malinverno, A., Cook, A.E., Daigle, H., Oryan, B., 2018. Glacial cycles influence marine methane hydrate formation. Geophysical Research Letters 45, 724-732. hydrates in fine-grained continental slope sediments often occupy isolated depth intervals surrounded by hydrate-free sediments. As they are not connected to deep gas sources, these hydrate deposits have been interpreted as sourced by in situ microbial methane. We investigate here the hypothesis that these isolated hydrate accumulations form preferentially in sediments deposited during Pleistocene glacial lowstands that contain relatively large amounts of labile particulate organic carbon, leading to enhanced microbial methanogenesis. To test this hypothesis, we apply an advection-diffusion-reaction model with a time-dependent organic carbon deposition controlled by glacioeustatic sea level variations. In the model, hydrate forms in sediments with greater organic carbon content deposited during the penultimate glacial cycle (~120–240 ka). The model predictions match hydrate-bearing intervals detected in three sites drilled on the northern Gulf of Mexico continental slope, supporting the hypothesis of hydrate formation driven by enhanced organic carbon burial during glacial lowstands.Mamet, S.D., Ma, B., Ulrich, A., Schryer, A., Siciliano, S.D., 2018. Who is the rock miner and who is the hunter? The use of heavy-oxygen labeled phosphate (P18O4) to differentiate between C and P fluxes in a benzene-degrading consortium. Environmental Science & Technology 52, 1773-1786. availability and cycling in microbial communities is a key determinant of bacterial activity. However, identifying organisms critical to P cycling in complex biodegrading consortia has proven elusive. Here we assess a new DNA stable isotope probing (SIP) technique using heavy oxygen-labeled phosphate (P18O4) and its effectiveness in pure cultures and a nitrate-reducing benzene-degrading consortium. First, we successfully labeled pure cultures of Gram-positive Micrococcus luteus and Gram-negative Bradyrhizobium elkanii and separated isotopically light and heavy DNA in pure cultures using centrifugal analyses. Second, using high-throughput amplicon sequencing of 16S rRNA genes to characterize active bacterial taxa (13C-labeled), we found taxa like Betaproteobacteria were key in denitrifying benzene degradation and that other degrading (nonhydrocarbon) inactive taxa (P18O4-labeled) like Staphylococcus and Corynebacterium may promote degradation through production of secondary metabolites (i.e., “helper” or “rock miner” bacteria). Overall, we successfully separated active and inactive taxa in contaminated soils, demonstrating the utility of P18O4-DNA SIP for identifying actively growing bacterial taxa. We also identified potential “miner” bacteria that choreograph hydrocarbon degradation by other microbes (i.e., the “hunters”) without directly degrading contaminants themselves. Thus, while several taxa degrade benzene under denitrifying conditions, microbial benzene degradation may be enhanced by both direct degraders and miner bacteria.Marcinkowski, M.D., Darby, M.T., Liu, J., Wimble, J.M., Lucci, F.R., Lee, S., Michaelides, A., Flytzani-Stephanopoulos, M., Stamatakis, M., Sykes, E.C.H., 2018. Pt/Cu single-atom alloys as coke-resistant catalysts for efficient C–H activation. Nature Chemistry 10, 325-332. recent availability of shale gas has led to a renewed interest in C–H bond activation as the first step towards the synthesis of fuels and fine chemicals. Heterogeneous catalysts based on Ni and Pt can perform this chemistry, but deactivate easily due to coke formation. Cu-based catalysts are not practical due to high C–H activation barriers, but their weaker binding to adsorbates offers resilience to coking. Using Pt/Cu single-atom alloys (SAAs), we examine C–H activation in a number of systems including methyl groups, methane and butane using a combination of simulations, surface science and catalysis studies. We find that Pt/Cu SAAs activate C–H bonds more efficiently than Cu, are stable for days under realistic operating conditions, and avoid the problem of coking typically encountered with Pt. Pt/Cu SAAs therefore offer a new approach to coke-resistant C–H activation chemistry, with the added economic benefit that the precious metal is diluted at the atomic limit.Mari, X., Passow, U., Migon, C., Burd, A.B., Legendre, L., 2017. Transparent exopolymer particles: Effects on carbon cycling in the ocean. Progress in Oceanography 151, 13-37. Exopolymer Particles (TEP) have received considerable attention since they were first described in the ocean more than 20years ago. This is because of their carbon-rich composition, their high concentrations in ocean’s surface waters, and especially because of their ability to promote aggregation due to their high stickiness (i.e.biological glue). As large aggregates contribute significantly to vertical carbon flux, TEP are commonly seen as a key factor that drives the downward flux of particulate organic carbon (POC). However, the density of TEP is lower than that of seawater, which causes them to remain in surface waters and even move upwards if not ballasted by other particles, which often leads to their accumulation in the sea surface microlayer. Hence we question here the generally accepted view that TEP always increase the downward flux of POC via gravitational settling. In the present reassessment of the role of TEP, we examine how the presence of a pool of non-sinking carbon-rich particulate organic matter in surface waters influences the cycling of organic carbon in the upper ocean at daily to decadal time scales. In particular, we focus on the role of TEP in the retention of organic carbon in surface waters versus downward export, and discuss the potential consequences of climate change on this process and on the efficiency of the biological carbon pump. We show that TEP sink only when ballasted with enough high-density particles to compensate their low density, and hence that their role in vertical POC export is not solely linked to their ability to promote aggregation, but also to their contribution to the buoyancy of POC. It follows that the TEP fraction of POC determines the degree of retention and remineralization of POC in surface waters versus its downward export. A high TEP concentration may temporally decouple primary production and downward export. We identify two main parameters that affect the contribution of TEP to POC cycling; TEP stickiness, and the balance between TEP production and degradation rates. Because stickiness, production and degradation of TEP vary with environmental conditions, the role of TEP in controlling the balance between retention versus export, and hence the drawdown of atmospheric CO2 by the biological carbon pump, can be highly variable, and is likely to be affected by climate change.Marin-Carbonne, J., Remusat, L., Sforna, M.C., Thomazo, C., Cartigny, P., Philippot, P., 2018. Sulfur isotope's signal of nanopyrites enclosed in 2.7 Ga stromatolitic organic remains reveal microbial sulfate reduction. Geobiology 16, 121-138. sulfate reduction (MSR) is thought to have operated very early on Earth and is often invoked to explain the occurrence of sedimentary sulfides in the rock record. Sedimentary sulfides can also form from sulfides produced abiotically during late diagenesis or metamorphism. As both biotic and abiotic processes contribute to the bulk of sedimentary sulfides, tracing back the original microbial signature from the earliest Earth record is challenging. We present in situ sulfur isotope data from nanopyrites occurring in carbonaceous remains lining the domical shape of stromatolite knobs of the 2.7-Gyr-old Tumbiana Formation (Western Australia). The analyzed nanopyrites show a large range of δ34S values of about 84‰ (from ?33.7‰ to +50.4‰). The recognition that a large δ34S range of 80‰ is found in individual carbonaceous-rich layers support the interpretation that the nanopyrites were formed in microbial mats through MSR by a Rayleigh distillation process during early diagenesis. An active microbial cycling of sulfur during formation of the stromatolite may have facilitated the mixing of different sulfur pools (atmospheric and hydrothermal) and explain the weak mass independent signature (MIF-S) recorded in the Tumbiana Formation. These results confirm that MSR participated actively to the biogeochemical cycling of sulfur during the Neoarchean and support previous models suggesting anaerobic oxidation of methane using sulfate in the Tumbiana environment.Martínez-Magadán, J.M., Cartas-Rosado, A.R., Oviedo-Roa, R., Cisneros-Dévora, R., Pons-Jiménez, M., Hernández-Altamirano, R., Zamudio-Rivera, L.S., 2018. Molecular design of high performance zwitterionic liquids for enhanced heavy-oil recovery processes. Journal of Molecular Graphics and Modelling 80, 264-271. Gemini zwitterionic liquids, which contain two zwitterionic moieties of linked quaternary-ammonium and carboxylate groups, are proposed as chemicals to be applied in the EOR from fractured carbonate reservoirs. The zwitterionic moieties are bridged between them through an alkyl chain containing 12 ether groups, and each zwitterionic moiety has attached a long alkyl tail including a CC double bond. A theoretical molecular mechanism over which EOR could rest, consisting on both the disaggregation of heavy oil and the reservoir-rock wettability alteration, was suggested. Results show that chemical can both reduce the viscosity and remove heavy-oil molecules from the rock surface.Matapour, Z., Karlsen, D.A., 2018. Ages of Norwegian oils and bitumen based on age-specific biomarkers. Petroleum Geoscience 24, 92-101. oils are generally considered sourced primarily from the Kimmeridge Clay equivalent shales such as the Draupne, Mandal, Spekk and Hekkingen formations, with secondary contributions from the mid–lower Jurassic, and also from the Triassic in the Barents Sea (Botneheia Formation). Still, as most of our age inferences concerning source-oil correlation are based on facies-specific biomarkers, a number of proposed correlations have been questioned.Thus, source to oil correlations were frequently made on the basis of facies parameters, and rightfully so, but facies-specific signatures in oils will transgress age – and, in principle, not correlate with the phylogenetic evolution. This means that one could, in principle assign an oil to ‘the wrong’ age – when one is, in fact, linking it to a known source rock signature.A series of 40 oil samples and core extracts, which cover a wide range both stratigraphically and geographically, have been analysed. In this paper, we present for the first time a Norwegian oil-age map based on age-specific biomarkers among the nordiacholestanes and triaromatic steroids parameters, and delineate also where we find Cretaceous- and Palaeozoic-derived oils. The reasons for this distribution pattern, compared to that of Mesozoic oils on the Norwegian Continental Shelf (NCS), are discussed.Maynard, A.D., 2018. Thinking differently about risk. Astrobiology 18, 244-245., C.P.P., Stedille, F.A., Mansur, C.R.E., Ramos, A.C.S., Lucas, E.F., 2018. Flocculation of asphaltenes by polymers: Influence of polymer solubility conditions. Energy & Fuels 32, 1087-1095. polystyrene has shown flexible action as an asphaltene dispersant/flocculant as a function of the degree of sulfonation and concentration used. In this work, samples of sulfonated polystyrene with different sulfonation degrees were assessed in precipitation assays in model asphaltene systems, with variation of the asphaltene fractions (asphaltenes extracted by n-pentane and n-heptane, C5I and C7I, respectively), asphaltene concentration, polymer concentration, and medium used to dissolve the polymer and asphaltenes. The precipitation tests were carried out with an ultraviolet–visible spectrometer, and the absorbance values were converted into asphaltene concentration values in solution by using calibration curves. The results showed that the concentration of sulfonic groups at which the polymer performs best as an asphaltene flocculant is 10 mol %. The dependence of the polymer’s effect as a flocculant or stabilizer of asphaltenes in function of its hydrophilicity and concentration was confirmed. Moreover, the results indicate there is a strong relationship between the polymer’s solubility in the medium and its flocculant action, which is significantly more effective when the polymer does not have strong affinity for the medium.McCrimmon, D.O., Bizimis, M., Holland, A., Ziolkowski, L.A., 2018. Supraglacial microbes use young carbon and not aged cryoconite carbon. Organic Geochemistry 118, 63-72. holes are depressions in glacial ice surfaces filled with dark debris that reduce albedo. The relative contributions of combustion and microbial carbon to cryoconite carbon are currently not known. To constrain cryoconite organic carbon composition and carbon sources to microorganisms living on glacier surfaces, measurements of bulk organic carbon and microbial phospholipid fatty acids (PLFAs) from supraglacial cryoconite sediment within the ablation zones of Spencer and Matanuska glaciers in southern Alaska were coupled with radiocarbon (14C) analyses. The 14C content of bulk cryoconite organic carbon on both glaciers was depleted relative to the modern atmosphere, while the PLFAs contained carbon that was recently in equilibrium with the atmosphere. Because the bulk cryoconite material is isotopically distinct from the PLFAs, these results indicate that cryoconite organic carbon is not bioavailable to the microbes. Instead, modern carbon in the microbes suggests that carbon is being quickly cycled by them within the cryoconite. Biomarker and stable isotope analyses of cryoconite organic carbon points to fresh carbon inputs to cryoconite and indicates that combusted fossil carbon is a not a major component of cryoconite organic carbon. Trace element analyses of the bulk cryoconite show crustal inputs and no evidence for excess metals associated with recent combustions sources, indicating that the aged bulk cryoconite organic carbon is likely of rock origin (e.g., shale). This study highlights that microbes in cryoconite holes on these glaciers are fixing atmospheric carbon and not using the aged carbon surrounding them.Meadows, V.S., Arney, G.N., Schwieterman, E.W., Lustig-Yaeger, J., Lincowski, A.P., Robinson, T., Domagal-Goldman, S.D., Deitrick, R., Barnes, R.K., Fleming, D.P., Luger, R., Driscoll, P.E., Quinn, T.R., Crisp, D., 2018. The habitability of Proxima Centauri b: Environmental states and observational discriminants. Astrobiology 18, 133-189. Centauri b provides an unprecedented opportunity to understand the evolution and nature of terrestrial planets orbiting M dwarfs. Although Proxima Cen b orbits within its star's habitable zone, multiple plausible evolutionary paths could have generated different environments that may or may not be habitable. Here, we use 1-D coupled climate-photochemical models to generate self-consistent atmospheres for several evolutionary scenarios, including high-O2, high-CO2, and more Earth-like atmospheres, with both oxic and anoxic compositions. We show that these modeled environments can be habitable or uninhabitable at Proxima Cen b's position in the habitable zone. We use radiative transfer models to generate synthetic spectra and thermal phase curves for these simulated environments, and use instrument models to explore our ability to discriminate between possible planetary states. These results are applicable not only to Proxima Cen b but to other terrestrial planets orbiting M dwarfs. Thermal phase curves may provide the first constraint on the existence of an atmosphere. We find that James Webb Space Telescope (JWST) observations longward of 10?μm could characterize atmospheric heat transport and molecular composition. Detection of ocean glint is unlikely with JWST but may be within the reach of larger-aperture telescopes. Direct imaging spectra may detect O4 absorption, which is diagnostic of massive water loss and O2 retention, rather than a photosynthetic biosphere. Similarly, strong CO2 and CO bands at wavelengths shortward of 2.5?μm would indicate a CO2-dominated atmosphere. If the planet is habitable and volatile-rich, direct imaging will be the best means of detecting habitability. Earth-like planets with microbial biospheres may be identified by the presence of CH4—which has a longer atmospheric lifetime under Proxima Centauri's incident UV—and either photosynthetically produced O2 or a hydrocarbon haze layer.Mehra, A., Maloof, A., 2018. Multiscale approach reveals that Cloudina aggregates are detritus and not in situ reef constructions. Proceedings of the National Academy of Sciences.: Little is known about how the Ediacaran index fossil Cloudina lived and what impact it had on its surroundings. This uncertainty is due to the fact that Cloudina often is preserved with the same mineralogy as the rocks in which it is found; the lack of density contrast means that traditional imaging techniques cannot be used to reconstruct and measure in situ Cloudina populations. Recently, researchers have suggested that Cloudina was a framework reef builder that actively adapted to changing environmental conditions. In this paper, we use a serial grinding and imaging technique to produce 3D models of Cloudina aggregates. Along with detailed field observations, we demonstrate that Cloudina populations are detritus and not in situ growth.Abstract: The earliest metazoans capable of biomineralization appeared during the late Ediacaran Period (635–541 Ma) in strata associated with shallow water microbial reefs. It has been suggested that some Ediacaran microbial reefs were dominated (and possibly built) by an abundant and globally distributed tubular organism known as Cloudina. If true, this interpretation implies that metazoan framework reef building—a complex behavior that is responsible for some of the largest bioconstructions and most diverse environments in modern oceans—emerged much earlier than previously thought. Here, we present 3D reconstructions of Cloudina populations, produced using an automated serial grinding and imaging system coupled with a recently developed neural network image classifier. Our reconstructions show that Cloudina aggregates are composed of transported remains while detailed field observations demonstrate that the studied reef outcrops contain only detrital Cloudina buildups, suggesting that Cloudina played a minor role in Ediacaran reef systems. These techniques have wide applicability to problems that require 3D reconstructions where physical separation is impossible and a lack of density contrast precludes tomographic imaging techniques.Meindl, R.S., Chaney, M.E., Lovejoy, C.O., 2018. Early hominids may have been weed species. Proceedings of the National Academy of Sciences 115, 1244-1249.: Earliest hominids demonstrate major differences from fundamental behaviors typical of other primates. These included upright walking, a reduction in canine dimorphism, and unusual demographic success. All three were likely parts of a comprehensive adaptive complex that was also unlike that of any other primate and likely reflect a novel social structure. When primate “weed species,” such as some macaques, are examined for those key behavioral features most responsible for their unusual great demographic success, an irregular but robust elevation of female survivorship emerges as key. It is likely that a similar adaptation characterized earliest hominids such as Australopithecus. Abstract: Panid, gorillid, and hominid social structures appear to have diverged as dramatically as did their locomotor patterns as they emerged from a late Miocene last common ancestor (LCA). Despite their elimination of the sectorial canine complex and adoption of bipedality with its attendant removal of their ready access to the arboreal canopy, Australopithecus was able to easily invade novel habitats after florescence from its likely ancestral genus, Ardipithecus sp. Other hominoids, unable to sustain sufficient population growth, began an inexorable decline, culminating in their restriction to modern refugia. Success similar to that of earliest hominids also characterizes several species of macaques, often termed “weed species.” We here review their most salient demographic features and find that a key element is irregularly elevated female survival. It is reasonable to conclude that a similar feature characterized early hominids, most likely made possible by the adoption of social monogamy. Reduced female mortality is a more probable key to early hominid success than a reduction in birth space, which would have been physiologically more difficult. Melin, H., Fletcher, L.N., Donnelly, P.T., Greathouse, T.K., Lacy, J.H., Orton, G.S., Giles, R.S., Sinclair, J.A., Irwin, P.G.J., 2018. Assessing the long-term variability of acetylene and ethane in the stratosphere of Jupiter. Icarus 305, 301-313. (C2H2) and ethane (C2H6) are both produced in the stratosphere of Jupiter via photolysis of methane (CH4). Despite this common source, the latitudinal distribution of the two species is radically different, with acetylene decreasing in abundance towards the pole, and ethane increasing towards the pole. We present six years of NASA IRTF TEXES mid-infrared observations of the zonally-averaged emission of methane, acetylene and ethane. We confirm that the latitudinal distributions of ethane and acetylene are decoupled, and that this is a persistent feature over multiple years. The acetylene distribution falls off towards the pole, peaking at ?～?30°N with a volume mixing ratio (VMR) of ?～?0.8 parts per million (ppm) at 1 mbar and still falling off at ?±?70° with a VMR of ?～?0.3?ppm. The acetylene distributions are asymmetric on average, but as we move from 2013 to 2017, the zonally-averaged abundance becomes more symmetric about the equator. We suggest that both the short term changes in acetylene and its latitudinal asymmetry is driven by changes to the vertical stratospheric mixing, potentially related to propagating wave phenomena. Unlike acetylene, ethane has a symmetric distribution about the equator that increases toward the pole, with a peak mole fraction of ?～?18?ppm at about ?±?50° latitude, with a minimum at the equator of ?～?10?ppm at 1 mbar. The ethane distribution does not appear to respond to mid-latitude stratospheric mixing in the same way as acetylene, potentially as a result of the vertical gradient of ethane being much shallower than that of acetylene. The equator-to-pole distributions of acetylene and ethane are consistent with acetylene having a shorter lifetime than ethane that is not sensitive to longer advective timescales, but is augmented by short-term dynamics, such as vertical mixing. Conversely, the long lifetime of ethane allows it to be transported to higher latitudes faster than it can be chemically depleted.Mendhe, V.A., Mishra, S., Varma, A.K., Kamble, A.D., Bannerjee, M., Singh, B.D., Sutay, T.M., Singh, V.P., 2018. Geochemical and petrophysical characteristics of Permian shale gas reservoirs of Raniganj Basin, West Bengal, India. International Journal of Coal Geology 188, 1-24. shale horizons of Permian age emerged as the potential source of gas through primary investigation, and resulted into the first Indian pilot-scale gas recovery demonstration project in the Raniganj basin. However, the relation of geochemical properties with shale pore matrix, porosity and permeability mechanism are yet to be evaluated for better dealing the phenomena of diffusion, transport and gas recovery. In this study, the analyses like proximate, Rock-Eval, TOC, VRo, low pressure N2 sorption, porosity, permeability, SEM-EDX and image processing have been carried out. The values of S1, S2, TOC and Tmax indicated fair to excellent source rock potential of the shales having type III/IV kerogens prone to thermal gas genesis. The low pressure N2 desorption curve of Raniganj Formation shales shows the Type H3 hysteresis comprising slit-shaped pores. The Barren Measures shales have Type H2 and H3 hysteresis patterns specifying to ink bottle-shaped pores and slit-shaped pores. Whereas, the oldest Barakar Formation shales are having ink bottle-shaped pores caused due to blocking effect. The slit-shaped pores favour the pore network and characteristically excellent for the flow of gas. The results of SEM-EDX are indicating alteration stability in the order of O < C < Si < Al < Fe < K < Na < Ca following the trend of least to strong weathering (Barakar < Barren Measures < Raniganj). The siliciclastic facies (Al-Si-Fe) signifying massive and laminated shale beds deposited under fluvio-lacustrine palaeoenvironment favouring alteration and accumulation of K-feldspar and aluminous minerals to clay.The increasing Tmax values with a centric decrease in porosity and permeability, specifying the role of devolatilization, disintegration and blocking of pore spaces/openings is a function of the thermal gradient. The linear evolution of multipoint BET surface area with increasing porosity suggests that the porosity values from 2.0 to 6.5% mainly corresponds to pore size of 3.0–11.0 nm. Similarly, the inverse relationship between average pore size and porosity attributed to a greater contribution of smaller pores in total porosity. The pore network model derived through the SEM image processing has shown two types of connectivity - i) various pore sizes of diverse pore throats with dual opening directions, and ii) interlinked large and small pores obeying similar normal distributions. The Barren Measures shales have shown higher pore connectivity than the Raniganj and Barakar Formation shales.Meng, Q., Wang, X., Wang, X., Lei, Y., Liu, P., Zhang, L., Jiang, C., Gao, C., 2018. Biodegradation of light hydrocarbon (C5-C8) in shale gases from the Triassic Yanchang Formation, Ordos basin, China. Journal of Natural Gas Science and Engineering 51, 183-194. based on the molecular, carbon and hydrogen isotopic composition of shale gas has shown that the biodegradation level of the Yanchang Formation shale gas decreases markedly with increasing depth in some parts of the Ordos basin. The compositions of a suite of 30 shale desorbed gases from the Upper Triassic Yanchang Formation, Ordos basin, China, were analyzed in order to assess the effect of variable levels of biodegradation on the distribution of light hydrocarbons in the shale gas and to investigate the effect of biodegradation on common light hydrocarbon parameters. By comparison and analysis of the gas chromatograms of shale desorbed gas from different depths, a series of light hydrocarbon parameters reflecting biodegradation were established. The results indicate that the order of preferential biodegradation of light hydrocarbon fractions (C5-C8) is C5>C6>C7≈C8 and that the C6 fraction composition is n-Hexane (nC6)>2-methypentane (2-MP) ≈3-methypentane (3-MP)> Methylcyclopentane (MCP)>2,3-Dimethybutane (2,3-DMB)>2,2-Dimethybutane (2,2-DMB)>Cyclohexane (CH). There are three main controls on the susceptibility to biodegradation of light hydrocarbons: carbon skeleton, degree of alkylation, and position of alkylation. If the carbon skeleton is the same, a higher degree of alkylation represents a stronger ability to resist biodegradation. If the degree of alkylation is the same, those alkanes with larger carbon skeletons are more resistant to biodegradation. Finally, light hydrocarbon fractions with two methyl groups in the same position are more resistant to biodegradation than hydrocarbons with two methyl groups in different positions. Most of the light hydrocarbon parameters were influenced by biodegradation, except the Mango parameters K1and K2.Merey, ?., Longinos, S.N., 2018. Numerical simulations of gas production from Class 1 hydrate and Class 3 hydrate in the Nile Delta of the Mediterranean Sea. Journal of Natural Gas Science and Engineering 52, 248-266. hydrate reservoirs are considered as near-future energy resources in the world. As well as the many places in the world, there is also gas hydrate potential in the Mediterranean Sea. In this study, by using the literature data, it was aimed to understand whether the Mediterranean Sea includes necessary parameters for producible gas hydrate reservoirs. It was shown that the Mediterranean Sea contains all of these parameters (source gas, appropriate pressure and temperature, coarse sand potential, etc.). The only bottom-simulating reflections (BSRs) were detected in the Nile Delta of the Mediterranean Sea. In the conditions of these BSRs, the gas production potentials from Class 1 hydrate and Class 3 hydrate were analyzed by applying depressurization method with and without wellbore heating at 50?°C with HydrateResSim numerical simulator. It was observed that both gas hydrate layer in Class 1 and gas hydrate in Class 3 hydrate dissociated fully. However, the contribution of free gas layer in Class 1 hydrate on cumulative gas production was enormous so it was stated much more exploration studies are necessary in the Mediterranean Sea to detect Class 1 hydrates and BSRs. During the simulations, ice formations along the wellbores were not detected for both Class 1 hydrate and Class 3 hydrate. Hydrate reformation at 3.5?MPa and below 3.5?MPa in Class 3 hydrate was observed along the wellbore but the wellbore heating at 50?°C was enough to avoid gas hydrate reformation along the wellbore. The warm temperature of the sediments of the Mediterranean Sea was advantageous for effective depressurization. However, it was proved that methane-carbon dioxide replacement method is not applicable for the potential Mediterranean Sea gas hydrates due to the warm seafloor temperature (～14?°C) of the Mediterranean Sea.Milton, C.J., 2018. Geophysics and geochemistry; an interdisciplinary approach to archaeology in wetland contexts. Journal of Archaeological Science: Reports 18, 197-212. are a non-renewable resource of high potential for organic archaeological deposits and palaeoenvironmental sequences. This resource is at threat from development and climate change. Only a small percentage of the identified wetlands in North West Europe have been studied with regard to their depth, stratigraphic architecture and the heritage assets they contain. In this paper several case studies are combined to show the variation of radar velocity field with different wetland sediment types. Sediment types are classified based on their physical and chemical properties. The results demonstrate how the application of geophysics can be used to identify archaeological features and interpret them within a wetland landscape. The ground penetrating radar (GPR) response and geochemical signatures given by archaeological structures and palaeolandscape features, presented here improves the quality and reliability of scientific information derived from archaeological prospection in wetland contexts. More accurate values for the dielectric permittivity of different wetland sediments have been calculated, allowing the response of GPR in wetland contexts to be predicted. Geochemical signatures associated with different sediment types and archaeological structures have also been demonstrated. Both GPR and the geochemical analysis of sediment can be employed across the dryland wetland interface bridging the gap between wetland and dryland archaeology and offers a potential to shape global debates regarding how wetland heritage is managed in the future.Molari, M., Guilini, K., Lott, C., Weber, M., de Beer, D., Meyer, S., Ramette, A., Wegener, G., Wenzh?fer, F., Martin, D., Cibic, T., De Vittor, C., Vanreusel, A., Boetius, A., 2018. CO2 leakage alters biogeochemical and ecological functions of submarine sands. Science Advances 4, Article eaao2040. CO2 storage is considered a future climate change mitigation technology. We investigated the ecological consequences of CO2 leakage for a marine benthic ecosystem. For the first time with a multidisciplinary integrated study, we tested hypotheses derived from a meta-analysis of previous experimental and in situ high-CO2 impact studies. For this, we compared ecological functions of naturally CO2-vented seafloor off the Mediterranean island Panarea (Tyrrhenian Sea, Italy) to those of nonvented sands, with a focus on biogeochemical processes and microbial and faunal community composition. High CO2 fluxes (up to 4 to 7 mol CO2 m?2 hour?1) dissolved all sedimentary carbonate, and comigration of silicate and iron led to local increases of microphytobenthos productivity (+450%) and standing stocks (+300%). Despite the higher food availability, faunal biomass (?80%) and trophic diversity were substantially lower compared to those at the reference site. Bacterial communities were also structurally and functionally affected, most notably in the composition of heterotrophs and microbial sulfate reduction rates (?90%). The observed ecological effects of CO2 leakage on submarine sands were reproduced with medium-term transplant experiments. This study assesses indicators of environmental impact by CO2 leakage and finds that community compositions and important ecological functions are permanently altered under high CO2.Molinier, V., Le Goué, E., Rondón-Gonzáles, M., Passade-Boupat, N., Bourrel, M., 2018. Optimization of chemical dispersants effectiveness in case of subsurface oil spill. Colloids and Surfaces A: Physicochemical and Engineering Aspects 541, 43-51. spill dispersants used in the case of subsea release exhibit different efficiencies depending on the nature of oil and the salinity of water. This variability can be rationalized by considering the location of the optimal formulation of the dispersant/oil/water system, in the light of the concepts used for optimizing surfactants blends for other applications, in particular eor (enhanced oil recovery). In practice, the number of commercially-available dispersants is constrained by the thorough studies necessary for their registration, in particular as regards to their fate in the environment. Therefore a fair ability to disperse a wide range of potential spills is generally looked for. We show that the optimal formulation approach can be used to adapt the composition of the surfactant blend – hydrophilic and hydrophobic sorbitan esters and sodium dioctylsulfosuccinate–for the dispersion of different crude oils in waters of given salinities, thus allowing a significant increase in dispersion efficiency with a minimal variation of the overall product composition.Monnier, G., Frahm, E., Luo, B., Missal, K., 2018. Developing FTIR microspectroscopy for the analysis of animal-tissue residues on stone tools. Journal of Archaeological Method and Theory 25, 1-44. analysis of microscopic residues on stone tools provides one of the most direct ways to reconstruct the functions of such artifacts. However, new methods are needed to strengthen residue identifications based upon visible-light microscopy. In this work, we establish that reflectance Fourier-transform infrared microspectroscopy (FTIRM) can be used to document IR spectra of animal-tissue residues on experimental stone tools. First, we present a set of reflectance FTIRM standards for the most commonly identified animal-tissue residues on stone tools: skin, meat, fat, hair, blood, feather barbules, fish scales, and bone. We provide spectral peak assignments for each residue and demonstrate that high-quality reflectance FTIRM spectra can be generated under ideal circumstances. Second, we document the spectra for these residues when they are located on a stone substrate such as flint or obsidian. We discuss procedures for correcting spectra that are affected by specular reflection and explain the effects of spectral interference from the stone. Our results show that reflectance FTIRM is sensitive to small intra-sample differences in composition. This means that it will record the effects of decomposition in ancient residues. The methodological developments we present here will help lithic residue analysts incorporate in situ reflectance FTIRM into their analysis?protocols to strengthen identifications.Monroe, J.G., Markman, D.W., Beck, W.S., Felton, A.J., Vahsen, M.L., Pressler, Y., 2018. Ecoevolutionary dynamics of carbon cycling in the Anthropocene. Trends in Ecology & Evolution 33, 213-225. change is altering natural selection globally, which could shift the evolutionary trajectories of traits central to the carbon (C) cycle. Here, we examine the components necessary for the evolution of C cycling traits to substantially drive changes in global C cycling and integrate these components into a framework of ecoevolutionary dynamics. Recent evidence points to the evolution of C cycling traits during the Anthropocene and the potential to significantly affect atmospheric CO2. We identify directions for further collaboration between evolutionary, ecosystem, and climate scientists to study these ecoevolutionary feedback dynamics and determine whether this evolution will ultimately accelerate or decelerate the current trend in rising atmospheric CO2.Montero, L., Sáez, V., von Baer, D., Cifuentes, A., Herrero, M., 2018. Profiling of Vitis vinifera L. canes (poly)phenolic compounds using comprehensive two-dimensional liquid chromatography. Journal of Chromatography A 1536, 205-215. canes, a pruning-derived by-product, possess a great amount of bioactive (poly)phenolic compounds belonging to different chemical classes, thus, having a good potential for further valorization. However, in order to properly design valorization strategies, the precise chemical composition of this material has to be known. Up to now, this chemical characterization has been based on analysis of different groups of components individually, due to difficulties related to their huge chemical variability. In this work, a comprehensive two-dimensional liquid chromatography-based method (LC × LC) is developed to obtain the profiles of (poly)phenolic compounds present in grapevine canes from several varieties. Three different set-ups have been tested and compared; the combination of diol and C18 columns produced the best results, allowing the characterization of the (poly)phenolic profile in around 80 min. This way, 81 different components were detected in the samples; most of them could be tentatively assigned using the information provided by the DAD and MS detectors employed. Indeed, it has been possible to detect in a single run components belonging to stilbenoids, procyanidins and prodelphinidins of varying degrees of polymerization, some of them not formerly described in this natural source. The method has shown extremely good separation capabilities, and is characterized by high effective peak capacity (842) and orthogonality (A0 = 78%). The obtained results demonstrate that Vitis vinifera L. canes may retain a great potential to be used as an underexploited natural source of bioactive compounds, with potential applications in different fields.Morée, A.L., Schwinger, J., Heinze, C., 2018. Southern Ocean controls of the vertical marine δ13C gradient – a modelling study. Biogeosciences Discussions 2018, 1-24. standardized 13C isotope, δ13C, is a widely used ocean tracer to study changes in ocean circulation, water mass ventilation, atmospheric pCO2 and the biological carbon pump on timescales ranging from decades to 10s of millions of years. δ13C data derived from ocean sediment core analysis provide information on δ13C of dissolved inorganic carbon and the vertical δ13C gradient (i.e., Δδ13C) in past oceans. In order to correctly interpret δ13C and Δδ13C variations, a good understanding is needed of the influence from ocean circulation, air-sea gas exchange and biological productivity on these variations. The Southern Ocean is a key region for these processes, and we show here that global mean Δδ13C is sensitive to changes in the biogeochemical state of the Southern Ocean. We conduct four idealised sensitivity experiments with the ocean biogeochemistry general circulation model HAMOCC2s to explore the effect of biogeochemical state changes of the (Southern) Oceans on atmospheric δ13C, pCO2, and marine δ13C and Δδ13C. The experiments cover changes in air-sea gas exchange rates, particulate organic carbon sinking rates, sea ice cover, and nutrient uptake efficiency – in an unchanged ocean circulation field. We conclude that the maximum variation of mean marine Δδ13C in response to (bio)geochemical change is ~?0.5?‰, which is about half of the reconstructed variation in Δδ13C over glacial-interglacial timescales. Locally, Δδ13C variations can surpass or even mirror the mean effects on Δδ13C due to the spatial variation in the sensitivity of δ13C to biogeochemical change. The (bio)geochemical environment of a sediment core thus needs to be well constrained in order to be able to interpret reconstructed Δδ13C variations in such a core. The sensitivity of Δδ13C varies spatially depending on the contribution of air-sea gas exchange versus biological export productivity to the local δ13C signature. Interestingly, the direction of both glacial (intensification of Δδ13C) and interglacial (weakening of Δδ13C) Δδ13C change matches biogeochemical processes associated with these periods. This supports the idea that biogeochemistry likely explains part of the reconstructed variations in Δδ13C, and not only ocean circulation.Morga, R., Pawlyta, M., 2018. Microstructure of graptolite periderm in Silurian gas shales of Northern Poland. International Journal of Coal Geology 189, 1-7. samples of Silurian graptolite shales from an exploration borehole within the Baltic Basin were examined by optical microscopy, Raman spectroscopy and high resolution transmission electron microscopy. Graptolite periderm is composed of poorly ordered carbonaceous material of mainly aromatic structures. The dimension of the coherent domains is 1–2?nm. They are composed of two to three stacked layers. Raman spectral parameters of graptolite periderm are correlated with the mean random (Rr) and mean maximum (Rmax) reflectance of graptolites. The spectral ID1/IG ratio predicts thermal maturity in a mean reflectance of graptolites (Rr) range between 1.30% and 1.80% (Rmax?≈?1.40–2.00%; Vitrinite Reflectance Equivalent VRE?≈?1.10–1.50%). It is possible to calculate VRERaman from the ID1/IG ratio.Mori, T., Cahn, J.K.B., Wilson, M.C., Meoded, R.A., Wiebach, V., Martinez, A.F.C., Helfrich, E.J.N., Albersmeier, A., Wibberg, D., D?twyler, S., Keren, R., Lavy, A., Rückert, C., Ilan, M., Kalinowski, J., Matsunaga, S., Takeyama, H., Piel, J., 2018. Single-bacterial genomics validates rich and varied specialized metabolism of uncultivated Entotheonella sponge symbionts. Proceedings of the National Academy of Sciences.:: Uncultivated bacteria are hypothesized to represent a large resource of new bioactive natural products and biosynthetic enzymes. Previous work identified uncultivated “Entotheonella” symbionts of the sponge chemotype Theonella swinhoei Y as producers of a broad range of bioactive metabolites unknown from cultured bacteria. Here we present whole-genome data of an Entotheonella variant from a distinct chemotype of T. swinhoei. “Candidatus Entotheonella serta,” obtained from sponges from two oceans, possesses a biosynthetic complement even larger than, and nearly orthogonal to, those of the two previously described Entotheonella symbionts. This includes genes assigned to the misakinolides and theonellamides and suggests numerous additional natural products. The data validate Entotheonella as a rich and varied producer taxon with considerable biotechnological potential.Abstract: Marine sponges are prolific sources of unique bioactive natural products. The sponge Theonella swinhoei is represented by several distinct variants with largely nonoverlapping chemistry. For the Japanese chemotype Y harboring diverse complex polyketides and peptides, we previously provided genomic and functional evidence that a single symbiont, the filamentous, multicellular organism “Candidatus Entotheonella factor,” produces almost all of these compounds. To obtain further insights into the chemistry of “Entotheonella,” we investigated another phylotype, “Candidatus Entotheonella serta,” present in the T. swinhoei WA sponge chemotype, a source of theonellamide- and misakinolide-type compounds. Unexpectedly, considering the lower chemical diversity, sequencing of individual bacterial filaments revealed an even larger number of biosynthetic gene regions than for Ca. E. factor, with virtually no overlap. These included genes for misakinolide and theonellamide biosynthesis, the latter assigned by comparative genomic and metabolic analysis of a T. swinhoei chemotype from Israel, and by biochemical studies. The data suggest that both compound families, which were among the earliest model substances to study bacterial producers in sponges, originate from the same bacterium in T. swinhoei WA. They also add evidence that metabolic richness and variability could be a more general feature of Entotheonella symbionts.Moroeng, O.M., Wagner, N.J., Brand, D.J., Roberts, R.J., 2018. A Nuclear Magnetic Resonance study: Implications for coal formation in the Witbank Coalfield, South Africa. International Journal of Coal Geology 188, 145-155. this study, carbon-13 cross-polarization magic-angle-spinning solid-state nuclear magnetic resonance (13C CP-MAS SS NMR) was undertaken on a parent coal sample and its density-fractionated derivatives, an inertinite-rich and a vitrinite-rich sample, obtained from the Witbank Coalfield of South Africa (medium rank C bituminous coal). The formation of inertinite macerals has been extensively researched and the conclusions remain largely controversial. However, most research has been confined to northern hemisphere coals, which are typically dominated by vitrinite. South African coals are widely known for their high inertinite content. Earlier workers have ascribed the inertinite macerals, in their diversity, to aerial oxidation. However, this oxidation-only pathway fails to recognize that inertinite macerals can form through other processes such as charring of plant matter. Microscopically, charred matter possesses anatomical structures that closely resembles those observed in inertinite macerals, with lignin and/or cell walls largely preserved, perhaps mechanically fragmented or compressed in some instances. Based on the NMR structural parameters, the average aromatic cluster size in the inertinite-rich sample (petrographically dominated by fusinite, semifusinite of varying reflectance, and inertodetrinite) corresponds to monocyclic, 6-aromatic carbon rings. In the vitrinite-rich sample of the same coal, the cluster sizes are larger, corresponding to multi-ring aromatic hydrocarbons. The 6-carbon rings in the inertinite-rich sample are interpreted to correspond to guaiacol and syringol, the principal products of low-temperature (below 400?°C) lignin pyrolysis. Since charring depletes cellulose and moisture, fire-affected plant matter is interpreted to have a lower compaction potential than vitrinite-forming material, sustaining 6-aromatic carbon ring isolation in the former. Lignin-derived aromatic rings in compactable plant matter merge to form the multi-ring clusters present in the collotelinite- and collodetrinite-rich sample of the same coal.Moros, J., ElFaham, M.M., Laserna, J.J., 2018. Dual-spectroscopy platform for the surveillance of Mars mineralogy using a decisions fusion architecture on simultaneous LIBS-Raman data. Analytical Chemistry 90, 2079-2087. single platform, integrated by a laser-induced breakdown spectroscopy detector and a Raman spectroscopy sensor, has been designed to remotely (5 m) and simultaneously register the elemental and molecular signatures of rocks under Martian surface conditions. From this information, new data fusion architecture at decisions level is proposed for the correct categorization of the rocks. The approach is based on a decision-making process from the sequential checking of the spectral features representing the cationic and anionic counterparts of the specimen. The scrutiny of the LIBS response by using a moving-window algorithm informs on the diversity of the elemental constituents. The output rate of emission lines allows projecting in a loop the elements as the cationic counterpart of the rock. In parallel, the Raman response of the unknown is compared with all the molecular counterparts of the hypothesized cation that are stored in a spectral library. The largest similarity rate unveils the final identity of the unknown. The identification capabilities of the architecture have been underscored through blind tests of 10 natural rocks with different origins. The great majority of forecasts have matched with the real identities of the inspected targets. The strength of this platform to simultaneously acquire the multielemental and the molecular information from a specimen by using the same laser events greatly enhances the “on-surface” missions for the surveillance of mineralogy.Müller, R.D., Dutkiewicz, A., 2018. Oceanic crustal carbon cycle drives 26-million-year atmospheric carbon dioxide periodicities. Science Advances 4, Article eaaq0500. carbon dioxide (CO2) data for the last 420 million years (My) show long-term fluctuations related to supercontinent cycles as well as shorter cycles at 26 to 32 My whose origin is unknown. Periodicities of 26 to 30 My occur in diverse geological phenomena including mass extinctions, flood basalt volcanism, ocean anoxic events, deposition of massive evaporites, sequence boundaries, and orogenic events and have previously been linked to an extraterrestrial mechanism. The vast oceanic crustal carbon reservoir is an alternative potential driving force of climate fluctuations at these time scales, with hydrothermal crustal carbon uptake occurring mostly in young crust with a strong dependence on ocean bottom water temperature. We combine a global plate model and oceanic paleo-age grids with estimates of paleo-ocean bottom water temperatures to track the evolution of the oceanic crustal carbon reservoir over the past 230 My. We show that seafloor spreading rates as well as the storage, subduction, and emission of oceanic crustal and mantle CO2 fluctuate with a period of 26 My. A connection with seafloor spreading rates and equivalent cycles in subduction zone rollback suggests that these periodicities are driven by the dynamics of subduction zone migration. The oceanic crust-mantle carbon cycle is thus a previously overlooked mechanism that connects plate tectonic pulsing with fluctuations in atmospheric carbon and surface environments.Mullineaux, L.S., Metaxas, A., Beaulieu, S.E., Bright, M., Gollner, S., Grupe, B.M., Herrera, S., Kellner, J.B., Levin, L.A., Mitarai, S., Neubert, M.G., Thurnherr, A.M., Tunnicliffe, V., Watanabe, H.K., Won, Y.-J., 2018. Exploring the ecology of deep-sea hydrothermal vents in a metacommunity framework. Frontiers in Marine Science 5, 49. doi: 10.3389/fmars.2018.00049. inhabiting deep-sea hydrothermal vents are strongly influenced by the geological setting, as it provides the chemical-rich fluids supporting the food web, creates the patchwork of seafloor habitat, and generates catastrophic disturbances that can eradicate entire communities. The patches of vent habitat host a network of communities (a metacommunity) connected by dispersal of planktonic larvae. The dynamics of the metacommunity are influenced not only by birth rates, death rates and interactions of populations at the local site, but also by regional influences on dispersal from different sites. The connections to other communities provide a mechanism for dynamics at a local site to affect features of the regional biota. In this paper, we explore the challenges and potential benefits of applying metacommunity theory to vent communities, with a particular focus on effects of disturbance. We synthesize field observations to inform models and identify data gaps that need to be addressed to answer key questions including: 1) what is the influence of the magnitude and rate of disturbance on ecological attributes such as time to extinction or resilience in a metacommunity; 2) what interactions between local and regional processes control species diversity, and 3) which communities are 'hot spots' of key ecological significance. We conclude by assessing our ability to evaluate resilience of vent metacommunities to human disturbance (e.g., deep-sea mining). Although the resilience of a few highly disturbed vent systems in the eastern Pacific has been quantified, these values cannot be generalized to remote locales in the western Pacific or mid Atlantic where disturbance rates are different and information on local controls is missing.Mu?oz-Iglesias, V., Choukroun, M., Vu, T.H., Hodyss, R., Mahjoub, A., Smythe, W.D., Sotin, C., 2018. Phase diagram of the ternary water–tetrahydrofuran–ammonia system at low temperatures. Implications for clathrate hydrates and outgassing on Titan. ACS Earth and Space Chemistry 2, 135-146.’s icy shell is expected to contain predominantly methane clathrate hydrates, water ice Ih, and possibly ammonia hydrates, beneath a cover of diverse organics formed via atmospheric photochemistry. The dissociation of clathrate hydrates has long been inferred as a potential replenishment mechanism for atmospheric methane; however, pure methane clathrates would be stable all the way to the surface. The melting of ammonia hydrates and subsequent interaction with methane clathrates could favor the dissociation of clathrates at much lower temperatures, due to the strong antifreeze effect of ammonia. To better understand the phase behavior of clathrate hydrates in the presence of ammonia, we have developed phase diagrams for the ternary system water–ammonia–tetrahydrofuran at 1 bar and in the temperature range 77–280 K via differential scanning calorimetry and Raman spectroscopy. We have been able to determine how ammonia promotes the start of a partial dissociation of THF–clathrates at temperatures far colder than the liquidus. We have also established that this ternary system exhibits a complex chemistry, with multiple phases forming in thermodynamic equilibrium because of a phase separation between a THF-dominated liquid and a H2O–NH3 dominated liquid. In addition to the expected THF–clathrates, we report the formation of other mineral phases such as ammonia hydrates, a new THF–NH3-rich phase, and potentially mixed THF–NH3 clathrates. Partial dissociation of ～10% of the clathrate reservoir would release to Titan’s atmosphere methane amounts sufficient to sustain the hydrocarbon cycle for 650 My, which is commensurate with the age of the present atmosphere.Nakamura, M., Ikeda, Y., Matsumoto, A., Maki, H., Arakawa, H., 2018. Distribution of hydrocarbons in seabed sediments derived from tsunami-spilled oil in Kesennuma Bay, Japan. Marine Pollution Bulletin 128, 115-125. a result of the 2011 Great East Japan earthquake, about 11,000 kL of fuel oil was spilled into Kesennuma Bay, Miyagi Prefecture. This oil either accumulated in seabed sediments or was burned in a marine fire on the sea surface. We investigated spatial and temporal variations in the concentrations of oil and hydrocarbons. The maximum concentrations of n-hexane extract (NHE), total petroleum hydrocarbon (TPH), and polycyclic aromatic hydrocarbons (PAHs) in the sediments in 2012 were 8000, 1200, and 16.2 mg/kg (DW), respectively. NHE and TPH concentrations were high in the inner and west bay, and PAHs concentrations were high in the east bay. NHE and PAH concentrations didn't change; however, TPH concentrations decreased significantly with time. The total NHE in the sediment across the whole bay was estimated at 1685 kL and there was still about 13% of the original amount in the sediment in December 2014.Nannou, C.I., Boti, V.I., Albanis, T.A., 2018. Trace analysis of pesticide residues in sediments using liquid chromatography–high-resolution Orbitrap mass spectrometry. Analytical and Bioanalytical Chemistry 410, 1977-1989. present study describes the optimization and validation of an analytical method based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction and purification with dispersive solid-phase extraction?(dSPE) before analysis, followed by ultrahigh-performance liquid chromatography–high-resolution linear ion trap/Orbitrap (LTQ Orbitrap) mass spectrometry for the determination of 18 pesticides in sediment. To optimize process efficiency, parameters such as pH, extraction salts, sediment amount, and cleanup sorbents were evaluated. Identification was based on both accurate mass and retention time, and further confirmation was achieved by mass spectrometry fragmentation. The optimized analytical method demonstrated good validation characteristics, such as accuracy (recoveries from 70.8% to 106.2%), method quantification limits (below 10 ng g-1 for 89% of the pesticides selected), linearity (coefficient of determination greater than 0.9921 in all cases), precision (repeatability and reproducibility with standard deviations below 18% and 21%, respectively), and matrix effect (signal suppression was exhibited for almost all analytes). The overall method performance, expressed as process efficiency, ranged from 58.8% to 102.1%. The validated method was successfully applied to real samples collected along two rivers in northwestern Greece, revealing the presence of three selected pesticides but at levels below the method quantification limit.Newell, D.L., Carey, J.W., Backhaus, S.N., Lichtner, P., 2018. Experimental study of gravitational mixing of supercritical CO2. International Journal of Greenhouse Gas Control 71, 62-73. injection into saline aquifers for sequestration will initially result in buoyant supercritical (sc)CO2 trapped beneath the caprock seal. During this period, there is risk of CO2 migration out of the reservoir along wellbore defects or fracture zones. Dissolution of the scCO2 plume into brine results in solubility trapping and reduces this risk, but based on diffusion alone, this mechanism could take thousands of years. Gravitational (density-induced) mixing of CO2-saturated brine is shown to significantly accelerate this process in computational studies, but few experimental efforts have confirmed the phenomenon. Here, constant-pressure, 3-dimensional bench-scale experiments used the mass of added water to quantify the mass transfer of scCO2 into water-saturated porous media at 40–90?°C and 20?MPa, with Rayleigh numbers from 2093 to 16256. Experiments exhibit a period of 7–35X enhancement in mass transfer rates over diffusion, interpreted as gravitational mixing. Convective CO2 flux ranges from 1.6?×?10?2 to 4.8?×?10?3 mol?s?1?m?2 in the experiments. Results are used to benchmark a computational model using PFLOTRAN. Experiments show an early diffusive onset period that is shorter with rates much higher than predicted by models and observed in analog experiments. Both experiments and models show convective mixing periods and similar overall rates of CO2 mass transfer.Niu, Q., Cao, L., Sang, S., Zhou, X., Wang, Z., 2018. Anisotropic adsorption swelling and permeability characteristics with injecting CO2 in coal. Energy & Fuels 32, 1979-1991. changes of anisotropic adsorption–swelling and permeability with injecting CO2 in coal influence the CO2 injectivity during CO2-ECBM or CGS (ECBM = enhancing coal bed methane; CGS = CO2 geological sequestration). To strengthen the understanding of this issue, two special-made cubic coal samples were adopted to test the porosity, swelling, and permeability in parallel face cleat and bedding plane direction, parallel butt cleat and bedding plane direction, and vertical bedding plane direction. To quantitatively characterize the anisotropic porosity, anisotropic swelling, and anisotropic permeability, an anisotropy index was introduced in this work. The results show that porosity anisotropy reflects the pore connectivity in different directions, which fall in the order of parallel face cleat and bedding plane direction > parallel butt cleat and bedding plane direction > vertical bedding plane direction. The porosity varieties can be owed to the compaction effect, thermal evolution effect, banded structure, and cleat distribution in coal seams. The maximum swelling ratios of the vertical bedding plane direction to the parallel bedding plane direction are 2.30 in sample 1 and 1.89 in sample 2. However, the ratios of parallel face cleat to parallel butt cleat are 1.28 in sample 1 and 1.30 in sample 2. The inhomogeneity of matter composition in the vertical bedding direction and the difference of cleat distribution in various coal bands mainly cause the anisotropic swelling. Both injecting CO2 in coal and raising its temperature increase the anisotropy swelling index, but the effect of thermal swelling is quite weak. Adsorbing CO2 especially for supercritical CO2 will enhance the permeability anisotropy of coal. This is because the low-permeability cleat possesses higher permeability adsorption sensitivity and the bedding plane fracture with higher permeability instead does not produce a pronounced permeability drop because of its lower permeability adsorption sensitivity. Cleats that are easily affected by adsorption–swelling always serve as throats between fractures and the coal matrix in a high-anisotropic coal, which will restrain CO2 flow in coal pores. Accordingly, cleat seepage and corresponding potential enhanced permeability measures deserve being paid enough attention to in future research. This work clarifies the understanding and offers some implications for CO2 injecting into coal seams from the perspective of anistropic properties of coal.Nixon, Z., Michel, J., 2017. A review of distribution and quantity of lingering subsurface oil from the Exxon Valdez oil spill. Deep Sea Research Part II: Topical Studies in Oceanography 147, 20-26. lingering subsurface oil residues from the Exxon Valdez oil spill (EVOS) are, at present, patchily distributed across the geologically complex and spatially extensive shorelines of Prince William Sound and the Gulf of Alaska. We review and synthesize previous literature describing the causal geomorphic and physical mechanisms for persistence of oil in the intertidal subsurface sediments of these areas. We also summarize previous sampling and modeling efforts, and refine previously presented models with additional data to characterize the present-day linear and areal spatial extent, and quantity of lingering subsurface oil. In the weeks after the spill in March of 1989, approximately 17,750 t of oil were stranded along impacted shorelines, and by October of 1992, only ~2% of the mass of spilled oil was estimated to remain in intertidal areas. We estimate that lingering subsurface residues, generally between 5 and 20 cm thick and sequestered below 10–20 cm of clean sediment, are present over 30 ha of intertidal area, along 11.4 km of shoreline, and represent approximately 227 t or 0.6% of the total mass of spilled oil. These residues are typically located in finer-grained sand and gravel sediments, often under an armor of cobble- or boulder-sized clasts, in areas with limited groundwater flow and porosity. Persistence of these residues is correlated with heavy initial oil loading together with localized sheltering from physical disturbance such as wave energy within the beach face. While no longer generally bioavailable and increasingly chemically weathered, present removal rates for these remaining subsurface oil residues have slowed to nearly zero. The only remaining plausible removal mechanisms will operate over time scales of decades.Novaes, F.J.M., Kulsing, C., Bizzo, H.R., de Aquino Neto, F.R., Rezende, C.M., Marriott, P.J., 2018. Analysis of underivatised low volatility compounds by comprehensive two-dimensional gas chromatography with a short primary column. Journal of Chromatography A 1536, 75-81. two-dimensional gas chromatography (GC×GC) approaches with cryogenic modulation were developed for the qualitative analysis of selected low volatility compounds in raw coffee bean extracts, without derivatisation. The approaches employed short first (1D) and second (2D) dimension columns, specifically a 1D 65% phenyl methyl siloxane column (11 m) and a 2D 5% phenyl methyl siloxane column (1 m), which allowed elution of high molar mass compounds (e.g. > 600 Da). Solutes included hydrocarbons, fatty acids, diterpenes, tocopherols, sterols, diterpene esters, and di- and triacylglycerides. An oven temperature program up to 370 °C was employed. The effects of experimental conditions were investigated, revealing that the GC×GC results strongly depended on the cryogenic trap T, and oven T program. An appropriate condition was selected and further applied for group type analysis of low volatility compounds in green Arabica coffee beans. Retention indices were compiled for 1D GC analysis and were similar for the composite column data in GC×GC. The elution of some compounds was confirmed by use of authentic standards. The approach allowed direct analysis of coffee extract in ethyl acetate solution, with improved analyte peak capacity (approximately 200 compounds were detected) without prior fractionation or pre-treatment of the sample. This avoided potential hydrolysis of high molar mass conjugate esters as well as degradation of thermally labile compounds such as the derivatives of the diterpenes cafestol and kahweol.Nowak, J.A., Shrestha, P.M., Weber, R.J., McKenna, A.M., Chen, H., Coates, J.D., Goldstein, A.H., 2018. Comprehensive analysis of changes in crude oil chemical composition during biosouring and treatments. Environmental Science & Technology 52, 1290-1300. in crude oil reservoirs by sulfate-reducing microbial communities (SRCs) results in hydrogen sulfide production, precipitation of metal sulfide complexes, increased industrial costs of petroleum production, and exposure issues for personnel. Potential treatment strategies include nitrate or perchlorate injections into reservoirs. Gas chromatography with vacuum ultraviolet ionization and high-resolution time-of-flight mass spectrometry (GC-VUV-HTOF) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) combined with electrospray ionization were applied in this study to identify hydrocarbon degradation patterns and product formations in crude oil samples from biosoured, nitrate-treated, and perchlorate-treated bioreactor column experiments. Crude oil hydrocarbons were selectively transformed based on molecular weight and compound class in the biosouring control environment. Both the nitrate and the perchlorate treatments significantly reduced sulfide production; however, the nitrate treatment enhanced crude oil biotransformation, while the perchlorate treatment inhibited crude oil biotransformation. Nitrogen- and oxygen-containing biodegradation products, particularly with chemical formulas consistent with monocarboxylic and dicarboxylic acids containing 10–60 carbon atoms, were observed in the oil samples from both the souring control and the nitrate-treated columns but were not observed in the oil samples from the perchlorate-treated column. These results demonstrate that hydrocarbon degradation and product formation of crude oil can span hydrocarbon isomers and molecular weights up to C60 and double-bond equivalent classes ranging from straight-chain alkanes to polycyclic aromatic hydrocarbons. Our results also strongly suggest that perchlorate injections may provide a preferred strategy to treat biosouring through inhibition of biotransformation.Ntlhokwe, G., Muller, M., Joubert, E., Tredoux, A.G.J., de Villiers, A., 2018. Detailed qualitative analysis of honeybush tea (Cyclopia spp.) volatiles by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry and relation with sensory data. Journal of Chromatography A 1536, 137-150. volatile composition of honeybush (Cyclopia) species was studied by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOF-MS). Headspace-solid phase micro-extraction (HS-SPME) was used to extract the volatile compounds from tea infusions prepared from the three species C. genistoides, C. maculata and C. subternata. A total of 287 compounds were identified, 101 of which were confirmed using reference standards, while the remainder were tentatively identified using mass spectral and retention index (RI) data. The identification power of TOF-MS enabled the tentative identification of 147 compounds for the first time in honeybush tea. The majority of the compounds identified were common to all three Cyclopia species, although there were differences in their relative abundances, and some compounds were unique to each of the species. In C. genistoides, C. maculata and C. subternata 265, 257 and 238 compounds were identified, respectively. Noteworthy was the tentative identification of cinnamaldehyde in particular C. maculata samples, which points to the likely contribution of this compound to their distinct sensory profiles. This study emphasises the complexity of honeybush tea volatile composition and confirms the power of GC × GC combined with TOF-MS for the analysis of such complex samples.O’Donovan, C., Meade, A., Venditti, C., 2018. Dinosaurs reveal the geographical signature of an evolutionary radiation. Nature Ecology & Evolution 2, 452-458. dominated terrestrial ecosystems across the globe for over 100?million years and provide a classic example of an evolutionary radiation. However, little is known about how these animals radiated geographically to become globally distributed. Here, we use a biogeographical model to reconstruct the dinosaurs’ ancestral locations, revealing the spatial mechanisms that underpinned this 170-million-year-long radiation. We find that dinosaurs spread rapidly initially, followed by a significant continuous and gradual reduction in their speed of movement towards the Cretaceous/Tertiary boundary (66?million years ago). This suggests that the predominant mode of dinosaur speciation changed through time with speciation originally largely driven by geographical isolation—when dinosaurs speciated more, they moved further. This was gradually replaced by increasing levels of sympatric speciation (species taking advantage of ecological opportunities within their existing environment) as terrestrial space became a limiting factor. Our results uncover the geographical signature of an evolutionary radiation.Oczkowski, A., Taplin, B., Pruell, R., Pimenta, A., Johnson, R., Grear, J., 2018. Carbon stable isotope values in plankton and mussels reflect changes in carbonate chemistry associated with nutrient enhanced net production. Frontiers in Marine Science 5, 43. doi: 10.3389/fmars.2018.00043. ecosystems are inherently complex and potentially adaptive as they respond to changes in nutrient loads and climate. We documented the role that carbon stable isotope (δ13C) measurements could play in understanding that adaptation with a series of three Ecostat (i.e., continuous culture) experiments. We quantified linkages among δ13C, nutrients, carbonate chemistry, primary, and secondary production in temperate estuarine waters. Experimental culture vessels (9.1 L) containing 33% whole and 67% filtered (0.2 μm) seawater were amended with dissolved inorganic nitrogen (N) and phosphorous (P) in low (3 vessels; 5 μM N, 0.3 μM P), moderate (3 vessels; 25 μM N, 1.6 μM P), and high amounts (3 vessels; 50 μM N, 3.1 μM P). The parameters necessary to calculate carbonate chemistry, chlorophyll-a concentrations, and particulate δ13C values were measured throughout the 14 day experiments. Outflow lines from the experimental vessels fed 250 ml containers seeded with juvenile blue mussels (Mytilus edulis). Mussel subsamples were harvested on days 0, 7, and 14 and their tissues were analyzed for δ13C values. We consistently observed that particulate δ13C values were positively correlated with chlorophyll-a, carbonate chemistry, and to changes in the ratio of bicarbonate to dissolved carbon dioxide (HCO ? 3 HCO3-:CO2). While the relative proportion of HCO ? 3 HCO3- to CO2 increased over the 14 days, concentrations of each declined, reflecting the drawdown of carbon associated with enhanced production. Plankton δ13C values, like chlorophyll-a concentrations, increased over the course of each experiment, with the greatest increases in the moderate and high treatments. Trends in δ13C over time were also observed in the mussel tissues. Despite ecological variability and different plankton abundances the experiments consistently demonstrated how δ13C values in primary producers and consumers reflected nutrient availability, via its impact on carbonate chemistry. We applied a series of mixed-effects models to observational data from Narragansett Bay and the model that included in situ δ13C and percent organic matter was the best predictor of [HCO ? 3 HCO3-]. In temperate, plankton-dominated estuaries, δ13C values in plankton and filter feeders reflect net productivity and are a valuable tool to understand the production conditions under which the base of the food chain was formed.Okoro, C.C., Nwezza, E.E., Lin, J., 2018. Persistence of halophylic methanogens and oil-degrading bacteria in an offshore oil-producing facility. Geomicrobiology Journal 35, 323-333. communities in a high saline, Tetrakis-Hydroxymethyl Phosphonium Sulfate (THPS) and nitrate-treated Nigerian oil-producing facilities were investigated. Methanogens in produced water samples preferred methanol, while those in pig-run samples (oily wastes from pipelines) preferred H2/CO2, as substrates to produce methane and stimulate metal corrosion. The results coincide with the dominance of methylotrophic and hydrogenotrophic methanogens in the respective samples. The same microbial populations were also THPS and high salinity tolerant. The nitrate reducers and hydrocarbon degraders were also dominant in the reservoir. A more inclusive and effective mitigation strategy is therefore required to effectively tackle biocide resistant methanogens in biocide treated oilfield.Orellana, A., Laurenzi, I.J., MacLean, H.L., Bergerson, J.A., 2017. Statistically enhanced model of in situ oil sands extraction operations: An evaluation of variability in greenhouse gas emissions. Environmental Science & Technology 52, 947-954. gas (GHG) emissions associated with extraction of bitumen from oil sands can vary from project to project and over time. However, the nature and magnitude of this variability have yet to be incorporated into life cycle studies. We present a statistically enhanced life cycle based model (GHOST-SE) for assessing variability of GHG emissions associated with the extraction of bitumen using in situ techniques in Alberta, Canada. It employs publicly available, company-reported operating data, facilitating assessment of inter- and intraproject variability as well as the time evolution of GHG emissions from commercial in situ oil sands projects. We estimate the median GHG emissions associated with bitumen production via cyclic steam stimulation (CSS) to be 77 kg CO2eq/bbl bitumen (80% CI: 61–109 kg CO2eq/bbl), and via steam assisted gravity drainage (SAGD) to be 68 kg CO2eq/bbl bitumen (80% CI: 49–102 kg CO2eq/bbl). We also show that the median emissions intensity of Alberta’s CSS and SAGD projects have been relatively stable from 2000 to 2013, despite greater than 6-fold growth in production. Variability between projects is the single largest source of variability (driven in part by reservoir characteristics) but intraproject variability (e.g., startups, interruptions), is also important and must be considered in order to inform research or policy priorities.Ostroukhov, S.B., 2018. Genesis of higher petroleum alkyltoluenes. Petroleum Chemistry 58, 8-12. genesis of higher alkyltoluenes with a normal alkyl chain (n-ATs) has been studied. The conditions for their formation from both individual C18 (oleic and stearic) fatty acids and C14 alcohol in the thermocatalytic mode and from Tasmanites planktonic algae during noncatalytic thermal treatment have been considered. The feasibility of the formation of n-ATs has been confirmed by determining their composition and structure.Pagel, M., Bonifacie, M., Schneider, D.A., Gautheron, C., Brigaud, B., Calmels, D., Cros, A., Saint-Bezar, B., Landrein, P., Sutcliffe, C., Davis, D., Chaduteau, C., 2018. Improving paleohydrological and diagenetic reconstructions in calcite veins and breccia of a sedimentary basin by combining Δ47 temperature, δ18Owater and U-Pb age. Chemical Geology 481, 1-17. sedimentary basins, the precise temperature and timing at which relatively shallow (< 60 °C) diagenetic and tectonic events occur are poorly recorded by classic geothermometers and low-temperature thermochronometers. In this study, we apply a methodology coupling carbonate clumped isotope Δ47 thermometry with U-Pb geochronology. Calcite breccias and veins from the border of the Gondrecourt graben (eastern Paris Basin, France), in Kimmeridgian limestones, were observed by optical microscopy and cathodoluminescence. They display Δ47 values that are identical within uncertainties (ranging from 0.621 to 0.635‰), implying very uniform calcite deposition temperatures averaging 44 ± 4 °C for the three investigated zones. When Δ47 temperatures are combined with the measured oxygen isotope composition of the calcite (δ18Ocal between ? 9.0‰ and ? 8.3‰V-PDB), one can calculate the δ18O of the water (δ18Owater) from which these cement breccia and vein calcite precipitated. The δ18Owater are very uniform (average of ? 4.5 ± 1‰V-SMOW) and overall are consistent with a meteoric origin, however with a slight 18O–enrichment via interaction with limestones prior to precipitation. U-Pb dating by LA-ICP-MS yields a model age for three hydraulic breccias at 43–42 Ma and an age at 35 Ma for calcite veining obtained from a single vein sample. When considering the geothermal gradient, the surface temperature during the Eocene and erosion, the temperatures obtained by Δ47 thermometry suggest that there were hot waters circulating from the Middle Jurassic sequences below. Additional geochemical data (δ18Ocal, δ13Ccal, Rare Earth Elements, Mg, Mn and Sr compositions from a larger set of calcite breccias and veins from the area, together with published δD values of fluid inclusions) allow further characterization of the fluid from which the calcite phases precipitated. Notably, the whole suite of calcite shows a slight decrease in both δ18Ocal and δ13Ccal (δ18Ocal between ? 8.3‰ and ? 9.9‰V-PDB, δ13Ccal between 2.9‰ and 0.9‰V-PDB) and in Mg and Mn contents from breccia to veins, indicative of higher water:rock ratios during the vein stage and leaching of different source limestones. More broadly, this study demonstrates the potential improvement in diagenetic and paleohydrological research by combining U-Pb dating from the same calcite crystals as those analyzed for stable and clumped isotopes.Pan, B., Li, Y., Wang, H., Jones, F., Iglauer, S., 2018. CO2 and CH4 wettabilities of organic-rich shale. Energy & Fuels 32, 1914-1922. and CH4 wettabilities of organic-rich shale are important physicochemical parameters that significantly influence CO2 sequestration and CH4 production. However, there is a serious lack of understanding of these aspects because the data available are scarce. Thus, we evaluated organic-rich shale CO2 and CH4 wettabilities (i.e., brine/shale/gas systems) through advancing and receding brine contact angle measurements as a function of pressure, temperature, salinity, and ion type (as these can vary significantly in underground formations). The results indicated that the brine contact angles for both CO2/CH4–brine–shale systems increased with pressure and salinity, but decreased with temperature. However, these effects were much less significant for CH4. Furthermore, the brine contact angles for the CO2–brine–shale system reached 180° (i.e., the shale was completely wetted by CO2) when the pressure reached 30 MPa at 343 K and ～9 MPa at 298 K. The brine contact angles for the analogue CH4 systems was much lower (50°–90°), only indicating weakly water-wet to intermediate-wet conditions. Finally, the brine contact angles for CO2–brine–shale system were also larger for divalent ions (Ca2+, Mg2+) than for monovalent ions (Na+, K+), while ion type had no significant influence on CH4 wettability. However, a similar CO2/CH4 density resulted in a similar wettability. Consequently CH4 could not be used as a proxy for predicting CO2 storage capacities, unless they have similar densities.Pan, Y., Hui, D., Luo, P., Zhang, Y., Sun, L., Wang, K., 2018. Experimental investigation of the geochemical interactions between supercritical CO2 and shale: Implications for CO2 storage in gas-bearing shale formations. Energy & Fuels 32, 1963-1978. between injected CO2 and shale formation during the process of CO2 sequestration with enhancing shale gas recovery (CS-EGR) may alter the physical and chemical properties of the rock, affecting the efficiency of CO2 storage as well as CH4 production. To better understand these interaction-induced changes in shale properties, two shale samples selected from a marine Longmaxi formation and terrestrial Chang-7 member of the Yanchang formation were first reacted with supercritical CO2 (scCO2) in a laboratory batch reactor at 80 °C and 15 MPa with different time intervals, and then characterization methods were designed to access the geochemical changes including optical microscope (OM), X-ray diffraction (XRD), element analysis (EA), low-pressure gas adsorption (LPGA), and Fourier transform infrared spectroscopy (FTIR). The results indicate that the nanopore structure system of the two shale samples was significantly changed after scCO2–shale interaction due to the scCO2-induced extraction of hydrocarbons, chemical reactions in minerals, and the swelling effect in clay minerals as well as organic matter. However, after exposure to scCO2, the variation trend of pore structure parameters between the marine Longmaxi and terrestrial Chang-7 sample was quite different, which was related to the huge discrepancies in terms of mineralogy and geochemical properties between them. For marine Longmaxi sample, the pore surface area and pore volume obviously decreased after a relatively short period of scCO2 treatment, whereas an opposite trend was observed in a terrestrial Chang-7 sample after long-term scCO2 treatment. In addition, an obvious decrease in fractal dimensions for marine Longmaxi sample was also observed after scCO2 exposure, reflecting the degree of pore surface roughness, and pore structure complexity were reduced, whereas the terrestrial Chang-7 sample exhibited an opposite trend. The results contribute to the understanding of the potential factors for the pore-structure evolution during long-term CO2 storage and the possible effect on the CS-EGR process.Pang, Y., Soliman, M.Y., Sheng, J., 2018. Investigating gas-adsorption, stress-dependence, and non-Darcy-flow effects on gas storage and transfer in nanopores by use of simplified local density model. SPE Reservoir Evaluation and Engineering 21, 73-95. an unconventional rock, shale contains all the features of coalbed and tight sandstone specified as gas-adsorption capacity, microscale and nanoscale porosity, and extremely low permeability. The gas-storage mechanism of shale rocks not only is dominated by free gas in macropores and natural fractures, but also is controlled by adsorbed gas in microporous organic matter (kerogen) and clay minerals. Furthermore, Darcy’s law is no longer applicable to describe gas transport in nanopores (Javadpour 2009; Wu et al. 2015). Therefore, developing a reliable model to calculate effective porosity and permeability in nanopores considering the effects of gas adsorption, stress dependence, and non-Darcy flow is crucial to characterize properties of shale-gas reservoirs and explain gas-flow behavior in nanopores.In this study, the simplified local density (SLD) model, which has been successfully applied to analyze gas adsorption on coal, activated carbon, and shale in recent studies, is used to analyze methane-adsorption data measured from five shale-core plugs in the laboratory (Mohammad et al. 2011; Chareonsuppanimit et al. 2012; Clarkson and Haghshenas 2016). A new approach to determine the thickness of adsorbed gas dependent on the density profile of the SLD model is proposed, which in turn provides the correction of methane adsorption to pore volume (PV). Furthermore, stress-dependence effect is incorporated into the gas-adsorption effect to generate an effective porosity function in shale rocks. In addition, non-Darcy-flow effect on gas transfer in nanopores is derived from the slit-shaped pore geometry of the SLD model and is represented by a weighted sum of second-order gas slippage and Knudsen diffusion. Consequently, the effective permeability is established as a function of the effects of gas adsorption, stress dependence, and non-Darcy flow. Moreover, the functions of effective porosity and permeability are incorporated into a numerical simulator to perform history matching for gas-production data from a horizontal well with multistage hydraulic fractures in a Barnett Shale reservoir. The simulation results properly match the gas-production data at the field scale. Finally, sensitivity studies on gas adsorption, stress dependence, and non-Darcy-flow effects are conducted to investigate their contributions to evaluating and estimating gas production from shalegas reservoirs.The results of this study suggest that gas adsorption and non-Darcy-flow effects are two competitive aspects that have major influences on shale-gas production. The developed model including gas-adsorption, stress-dependence, and non-Darcy-flow effects provides insight into the characterization of rock properties and the description of gas-transport behavior in shale-gas reservoirs.Park, Y., Kim, S., Cho, S., Cha, J., An, S., 2018. Microbial community structure and activity changes in response to the development of hypoxia in a shallow estuary. Biogeosciences Discussions 2018, 1-43. examined the effects of changing from oxic to anoxic conditions on microbial communities using both biogeochemical and molecular approaches in a semi-enclosed estuary (Jinhae Bay, Republic of Korea). Total microbial activity, represented by oxygen demand in the water column (WOD) or sediment (SOD), revealed that the respective microbial communities in the water and sediment responded differently to low dissolved-oxygen (DO) conditions. In the sediment, SOD and the total microbial abundance, as assessed by quantitative polymerase chain reaction (qPCR) analysis, decreased under low DO conditions, indicating that the microbial adaptation to anaerobic metabolism was not well established during hypoxia development. In the water column, however, neither the total abundance of microbes nor the WOD were affected by hypoxic conditions. Regardless of DO concentration, WOD showed a positive correlation with water temperature, implying that the aerobic metabolism was sustained even under hypoxic conditions, through the intermittent supply of oxygen. In addition to the spatially different responses of microorganisms, unique responses of specific groups were noted in sulfur (S) and nitrogen (N) cycling microbes. Sulfide-oxidizing prokaryotes (SOP) dominated in the water column, and no significant changes were evident in their abundance or diversity with hypoxia. However, in sediment, distinctive sulfate-reducing bacteria (SRB) were present at each sampling period during hypoxia development (a SRB succession), implying that each SRB group has varying sensitivity to DO and other electron acceptors. Our results illustrated similarities in composition and activity of N-cycling microbes between the seasonal hypoxia and permanent oxygen minimum zone (OMZ). Vertical profiles of dissolved inorganic nitrogen, including ammonium (NH4+) and nitrate (NO3?), and changes in archaeal abundance indicated that the NH4+-oxidizing archaea (AOA) varied spatially and temporally, depending on NH4+ and oxygen availability in the water column, under mature hypoxic conditions. The intriguing N dynamics recently discovered in the OMZ might also be important in the coastal hypoxic zone.Parker, C.W., Auler, A.S., Barton, M.D., Sasowsky, I.D., Senko, J.M., Barton, H.A., 2018. Fe(III) reducing microorganisms from iron ore caves demonstrate fermentative Fe(III) reduction and promote cave formation. Geomicrobiology Journal 35, 311-322. banded iron formations (BIF) of Brazil are composed of silica and Fe(III) oxide lamina, and are largely covered by a rock cap of BIF fragments in a goethite matrix (canga). Despite both BIF and canga being highly resistant to erosion and poorly soluble, >3,000 iron ore caves (IOCs) have formed at their interface. Fe(III) reducing microorganisms (FeRM) can reduce the Fe(III) oxides present in the BIF and canga, which could account for the observed speleogenesis. Here, we show that IOCs contain a variety of microbial taxa with member species capable of dissimilatory Fe(III) reduction, including the Chloroflexi, Acidobacteria and the Alpha- Beta- and Gammaproteobacteria; however, Fe(III) reducing enrichment cultures from IOCs indicate the predominance of Firmicutes and Enterobacteriaceae, despite varying the carbon/electron donor, Fe(III) type, and pH. We used model-based inference to evaluate multiple candidate hypotheses that accounted for the variation in medium chemistry and culture composition. Model selection indicated that none of the tested variables account for the dominance of the Firmicutes in these cultures. The addition of H2 to the headspace of the enrichment cultures enhanced Fe(III) reduction, while addition of N2 resulted in diminished Fe(III) reduction, indicating that these Enterobacteriaceae and Firmicutes were reducing Fe(III) during fermentative growth. These results suggest that fermentative reduction of Fe(III) may play a larger role in iron-rich environments than expected. Our findings also demonstrate that FeRM are present within the IOCs, and that their reductive dissolution of Fe(III) oxides, combined with mass transport of solubilized Fe(II) by groundwater, could contribute to IOC formation.Parman, S., 2018. An Archaean mushy mantle. Nature Geoscience 11, 85-86. data reveal that Earth’s mantle melts more readily than previously thought, and may have remained mushy until two to three billion years ago.Earth was completely molten when it formed 4.56 billion years ago, and it has been cooling ever since. Today, most of the Earth has solidified. The outer part of the metallic iron core is still liquid — the last survivor of the originally molten Earth. But the rocky, silicate mantle that surrounds the core is largely solid. The mantle has probably been solid for most of Earth’s history. Or so we thought. Writing in Nature Geoscience, Andrault and colleagues1 present high-pressure melting experiments that indicate that the mantle can melt at temperatures 200 to 250 °C lower than previously thought. So, 2 to 3 billion years ago, when Earth was hotter than today, much of the mantle could have been partially molten. The transition from an early mushy mantle to a solid one may have generated several significant changes attributed to this time period, including the shift to plate tectonics.Earth’s temperature increases from essentially zero at the surface to thousands of degrees Celsius at the centre. But this geothermal gradient is not a simple, smooth curve. Chemical heterogeneities, phase changes and differing modes of heat transport (conduction versus convection) combine to yield a geothermal gradient with varying slopes and numerous jumps. The temperature at which the solid mantle begins to melt — the solidus — also increases with depth. The slope is generally shallower than the geothermal gradient and, at low pressures, the solidus can cross the geothermal gradient, causing melting to occur.Indeed, volcanic eruptions at Earth’s surface are evidence that the present-day mantle does melt in some places. Today, the mid-ocean ridges mark the primary location where the mantle solidus and geothermal gradient coincide (Fig. 1). Melting and magmatism at these ridges — which encircle the globe — produces two-thirds of our planet’s crust. Still, the proportion of the total mantle that melts is small because most of it exists at temperatures below the solidus.The mantle solidus is measured experimentally by heating rock samples representative of Earth’s interior over a range of pressures. But this is no easy task and has challenged experimentalists for decades, with studies producing widely disparate results. In most experiments, the presence of melt is determined by closely examining the sample after the experiment, once it has cooled to room temperature. However, finding tiny amounts of melt this way can be like searching for a needle in a haystack. Often the melts crystallize when the sample is cooled, making their identification nearly impossible.Andrault and colleagues1 use a different approach to measure the mantle solidus. They analyse their samples for the existence of melt in situ at extreme high pressure and temperature. This is technically quite challenging, but the researchers use X-ray diffraction and electrical conductivity to detect less than 1 vol% melt in their samples, thus providing possibly the best constraints yet on the mantle’s melting point. At relatively low pressures, their experiments match previous work2,3. However, at pressures above 7 GPa, which corresponds to a depth of about 200 km, they find that the mantle solidus is 200 to 250 °C lower than previous estimates2,3.Today, most of the mantle exists at temperatures below this newly determined solidus. But the early Earth was warmer. Although Earth’s exact cooling rate is not well constrained, it is plausible that 2 to 3 billion years ago, most of the mantle was above the solidus temperature and could have been mushy — composed of both magmatic melt and crystals. The existence of extensive mushy mantle would have lowered the viscosity of the mantle and changed the amount and types of volcanism on the planet.Many geologic observations suggest this period 2 to 3 billion years ago was a time of great change on Earth: there was a spike in crustal ages, indicative of either increased crustal production or preservation, some lava types ceased production, oxygen rose in the atmosphere for the first time, and the first pervasive signs of plate tectonics appeared4. What drove these changes is debated, but a transition from a mushy to a solid mantle provides a plausible and elegantly simple mechanism. Specifically, Andrault and colleagues propose that a mushy layer could have decoupled the mantle from the overlying lithosphere. As Earth cooled and the mush layer crystallized, the mantle and lithospheric plates could have become coupled, triggering the onset of subduction and plate tectonics, among other changes.Although the in situ methods used by Andrault and colleagues are sensitive to the presence of exceedingly small amounts of melt, they do not readily quantify the amount of melt present. Future work will need to measure how quickly the amount of melt increases as temperature rises above the solidus (the melting rate). Previous work5 suggests that the melting rate can be highly non-linear, with very low rates of melt production at temperatures near the solidus and a dramatic increase in melt production only when a threshold temperature is reached. The higher-temperature solidi found by previous less-sensitive experimental approaches2,3 may actually be this threshold point, where the melt percent rises above about 1 vol%. If so, the difference between the modern and ancient mantle may be the presence of only a small amount of melt. Whether that would be enough to explain the large changes seen 2 to 3 billion years ago is not yet clear.Andrault and colleagues1 use high-pressure experiments to show that the mantle solidus is lower than previously estimated, implying that it could have remained partially molten for much of the Archaean. Significant changes on Earth in this time period, including the initiation of plate subduction, may have resulted from this delayed solidificationReferences1. Andrault, D. et al. Nat. Geosci. (2018).2. Iwamori, H., McKenzie, D. & Takahashic, E. Earth Planet. Sci. Lett. 134, 253–266 (1995).3. Herzberg, C., Raterron, P. & Zhang, J. Geochem. Geophys. Geosyst. 1, 1051 (2000).4. O’Neill, C., Lenardic, A. & Condie, K. C. Geol. Soc. Lond. Spec. Publ. 389, 17–40 (2013).5. Hirschmann, M. M., Asimow, P. D., Ghiorso, M. S. & Stolper, E. M. J. Petrol. 40, 831–851 (1999).Parsons, B.A., Pinkerton, D.K., Synovec, R.E., 2018. Implications of phase ratio for maximizing peak capacity in comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry. Journal of Chromatography A 1536, 16-26. relationship between the phase ratio, β, of the primary (1D) and secondary (2D) separation dimensions of comprehensive two-dimensional (2D) gas chromatography (GC × GC) separations, and the implications of β on realization of maximal 2D peak capacity, nc,2D, are examined. A GC × GC chromatographic system with time-of-flight mass spectrometry, TOFMS, was otherwise held constant for the separation of a multi-component test mixture spanning a range of chemical functionalities, while only the β of the two analytical columns were changed, 1β for 1D and 2β for 2D. Six column sets were studied using common, commercially available β values. The β ratio, βR = 1β/2β, is defined as a quantitative metric to facilitate this study. It is demonstrated that βR plays a key role in maximizing nc,2D. Overall, βR substantially affected nc,2D by influencing retention factors on the 2D column, 2k, and thereby changing the modulation period, PM, necessary for proper 2D column separations. The necessary changes to PM modify the modulation ratio, MR, which affects the 1D column peak widths and 1nc due to the impact of undersampling. Through changes to 1β, the range of 2k can be controlled, with subsequent effects to both 2nc and 1nc. These effects were opposite in direction, such that improvements to 2nc may result in declines in 1nc. It is observed that due to the pseudo-isothermal nature of the 2D separation, there are diminishing returns to extending the 2nc at the cost of 1nc. In this particular study, column set 3 (1D: 20 m length, 250 μm i.d., 0.25 μm film; 2D: 2 m, 180 μm i.d., 0.2 μm film; βR = 1.11) with a PM of 3 s provided the highest theoretical nc,2D of ～8200, though this was at a relatively low MR of ～1.8. Column set 2 (1D: 20 m length, 250 μm i.d., 0.5 μm film; 2D: 2 m, 180 μm i.d., 0.2 μm film; βR = 0.56) with a PM of 1.5 s provided a high theoretical nc,2D of ～5800, at a much higher MR of ～3.7. Though column set 2 had a lesser total peak capacity than column set 3, its higher MR suggests that by improving the 1D column efficiency (i.e., narrowing the 1D column peak widths) to improve 1nc, can result in an increased theoretical nc,2D.Patriarca, C., Bergquist, J., Sj?berg, P.J.R., Tranvik, L., Hawkes, J.A., 2018. Online HPLC-ESI-HRMS method for the analysis and comparison of different dissolved organic matter samples. Environmental Science & Technology 52, 2091-2099. dissolved organic matter (DOM) is an ultracomplex mixture that is essential to global carbon cycling but is poorly understood because of its complexity. The most powerful tool for the DOM characterization is high-resolution mass spectrometry (HRMS) generally combined to direct infusion (DI) as sample introduction. Liquid chromatography (LC) represents a compelling alternative to DI; however, state-of-the-art techniques involve only offline LC-HRMS approaches, which have important logistical drawbacks that make DOM analysis more challenging. This study introduces a new method based on online coupling of liquid chromatography to high resolution mass spectrometry, able to overcome the disadvantages of usual approaches. It is characterized by high reproducibility (% Bray–Curtis dissimilarity among replicates ≈ 2.5%), and it reduces transient complexity and contaminant interferences, thus increasing the signal-to-noise ratio (S/N), leading to the identification of an overall larger number of formulas in the mixture. Moreover, the application of an in silico fractionation prior to the statistical analysis allows an easy, flexible, fast, and detailed comparison of DOM samples from a variety of sources with a single chromatographic run.Peggie, D.A., Kirby, J., Poulin, J., Genuit, W., Romanuka, J., Wills, D.F., De Simone, A., Hulme, A.N., 2018. Historical mystery solved: a multi-analytical approach to the identification of a key marker for the historical use of brazilwood (Caesalpinia spp.) in paintings and textiles. Analytical Methods 10, 617-623. derived from brazilwood (Caesalpinia spp.) are known to have been used in a diverse range of objects, from Medieval European textiles to North American First Nations objects, while pigments made from brazilwood feature in the palette of a number of painters, including Rembrandt and Van Gogh. For almost two decades, an unknown marker has been used to detect brazilwood colourants in historical objects. Limited sampling opportunities mean that the identification of the chemical structure of this marker has eluded scientists to date. Using a combination of synthesis, UPLC-ESI-MS/MS, HPLC, NMR and GC-MS, the identity of this unknown marker was confirmed as the benzochromenone, urolithin C. Structural identification provides a reliable reference compound for use across a range of analytical techniques employed in the cultural heritage sector and will enable the future development of non-destructive techniques for its identification on high-status objects.Pei, H., Shu, Z., Zhang, G., Ge, J., Jiang, P., Qin, Y., Cao, X., 2018. Experimental study of nanoparticle and surfactant stabilized emulsion flooding to enhance heavy oil recovery. Journal of Petroleum Science and Engineering 163, 476-483. is well known that the recovery of water flooding from heavy oil reservoirs is less than 30% or even 20% of the OOIP (original oil in place), due to its very high viscosity and thus extremely low mobility comparing to light oil at reservoir condition. In order to improve residual oil recovery after water flooding in ordinary heavy oil reservoirs, this study presents an experimental study of nanoparticle and surfactant stabilized emulsion flooding to enhance heavy oil recovery. It is indicated in the emulsion stability and rheology studies that the synergistic interaction of nanoparticle with surfactant can significantly improve the emulsion stability and increase the apparent viscosity of emulsion. The results of core flooding tests show that the residual oil recovery after water flooding can be significantly improved by the nanoparticle-surfactant stabilized emulsions flooding. The incremental oil recovery gradually increases with the increase of injected emulsion volume, but there is an optimal economic value of the injected volume. The low injection rate is more effective than high injection rate, and the continuous injection pattern shows higher tertiary oil recovery as compared to cyclic injection pattern. The nanoparticle-surfactant stabilized emulsion flooding has a great potential for enhanced oil recovery in waterflooded heavy oil reservoirs, with the permeability ranging from 500 mD to 2000 mD and the crude oil viscosity being lower than 1000?mPa?s. The two-dimensional homogeneous sandpack flooding test indicates that the nanoparticle-surfactant stabilized emulsion flooding can not only improve the sweep efficiency by blocking the high permeable water channels, but also can improve the displacement efficiency by mobilizing the trapped oil.Pérez-Huerta, A., Coronado, I., Hegna, T.A., 2018. Understanding biomineralization in the fossil record. Earth-Science Reviews 179, 95-122. – the formation of minerals by organisms – is a key aspect in the understanding of the fossil record. Knowing how biominerals form and their properties is important in the correct use of fossils in geochemistry, the understanding of evolution, and in the interpretation of how geological events have influenced the fossil record throughout the Phanerozoic. The focus of this contribution, rather than a conventional review on the status of this research field, is on the importance of highlighting the traditional link between paleontology and biomineralization.Peters, C.A., Hallmann, C., George, S.C., 2018. Phenolic compounds in oil-bearing fluid inclusions: Implications for water-washing and oil migration. Organic Geochemistry 118, 36-46. comparison to genetically related crude oils, oil-bearing fluid inclusions are often relatively enriched in polar compounds. Phenolic, carbazolic and benzocarbazolic compounds, which are part of the polar fraction, are characterised by elevated solubilities in water, rendering them potentially useful indicators for oil migration and entrapment, as well as water-washing of oil-bearing fluid inclusions. These compounds were investigated in a set of crude oils and fluid inclusions, and methods were modified to allow for the direct and simultaneous analysis of phenolic and carbazolic compounds. By avoiding chromatographic column fractionation, this new analytical approach allows for faster analyses and higher throughput. Phenolic and carbazolic compounds were found to be present in all investigated crude oil samples, yet they represent only minor constituents of oil-bearing fluid inclusions. A newly described phenol–cresol index (PCI) is systematically elevated (>?0.7) in oil-bearing fluid inclusions, while crude oils are characterised by significantly lower values (<?0.5). Supported by observations of increasing PCI during progressive water-washing experiments, our data suggest oil-water interaction as a possible reason for the elevated PCI in oil-bearing fluid inclusions. Moreover, some of the phenolic compounds detected in oil-bearing fluid inclusion samples may derive from co-occurring aqueous fluid inclusions, whose simultaneous co-extraction cannot be avoided on this spatial scale. Our study highlights the importance of oil-water interaction in the subsurface and offers new techniques to aid understanding of this commercially relevant phenomenon.Petkovic, O., Guibal, P., Sassiat, P., Vial, J., Thiébaut, D., 2018. Active modulation in neat carbon dioxide packed column comprehensive two-dimensional supercritical fluid chromatography. Journal of Chromatography A 1536, 176-184. demonstrating in a first paper the feasibility of SFCxSFC without decompression of the mobile phase, a modified interface has been developed in order to perform active modulation between the two SFC dimensions. In this paper, it is shown that the new interface enabled independent control of modulation parameters in SFCxSFC and performed a band compression effect of solutes between the two SFC dimensions. The effectiveness of this new modulation process was studied using a Design of Experiments. The SFCxSFC prototype was applied to the analysis of a real oil sample to demonstrate the benefits of the active modulator; in comparison to our previous results obtained without active modulation, better separation was obtained with the new interface owing to the peak compression occurring in the modulator.Pham, V.H.T., Chaudhary, D.K., Jeong, S.-W., Kim, J., 2018. Oil-degrading properties of a psychrotolerant bacterial strain, Rhodococcus sp. Y2-2, in liquid and soil media. World Journal of Microbiology and Biotechnology 34, 33. aim of this study was to investigate oil-degrading ability of newly isolated strain Rhodococcus Y2-2?at low temperature. Rhodococcus sp. Y2-2 was isolated from oil-contaminated soil sampled at the end of winter using a newly developed transwell plate method. In the liquid phase, the oil-degradation efficiency of strain Rhodococcus sp. Y2-2 was about 84% with an initial concentration of 1500?ppm TPH (500?ppm each of kerosene, gasoline, and diesel) when incubated for 2 weeks under optimal conditions: 10?°C, pH 7, and 0.5?g L??1 inoculum. In the soil phase, the isolate showed 80% oil degradation efficiency using glucose as a carbon source, with an initial concentration of 4000?ppm TPH and the addition of water during 14 days of incubation at 10?°C. Additionally, the degradation efficiency of the isolate was increased by the addition of mixture of surfactant alpha olefin sulfonate and gelatin, although strain Y2-2 also produced many biosurfactant components. This study shows Rhodococcus sp. Y2-2 can degrade oil components both in liquid and soil media by consuming kerosene, gasoline, and diesel as a carbon and energy source. Therefore, the crude oil-degrading ability of Rhodococcus sp. Y2-2?at low temperature provides proper bioremediation tool to clean up oil-contaminated sites especially in cold area or during winter season.Piao, J., Han, W.S., Choung, S., Kim, K.-Y., 2018. Dynamic behavior of CO2 in a wellbore and storage formation: Wellbore-coupled and salt-precipitation processes during geologic CO2 sequestration. Geofluids 2018, Article 1789278,. investigating the wellbore flow process in CO2 injection scenarios, coupled wellbore-reservoir (WR) and conventional equivalent porous media (EPM) models were compared with each other. In WR model, during the injection, conditions for the wellbore including pressure and temperature were dynamically changed from the initial pressure (7.45–8.33?MPa) and temperature (52.0–55.9°C) of the storage formation. After 3.35 days, the wellbore flow reached the steady state with adiabatic condition; temperature linearly increased from the well-head (35°C) to the well-bottom (52°C). In contrast, the EPM model neglecting the wellbore process revealed that CO2 temperature was consistently 35°C at the screen interval. Differences in temperature from WR and EPM models resulted in density contrast of CO2 that entered the storage formation (~200 and ~600?kg/m3, resp.). Subsequently, the WR model causing greater density difference between CO2 and brine revealed more vertical CO2 migration and counterflow of brine and also developed the localized salt-precipitation. Finally, a series of sensitivity analyses for the WR model was conducted to assess how the injection conditions influenced interplay between flow system and the localized salt-precipitation in the storage formation. Pittera, J., Jouhet, J., Breton, S., Garczarek, L., Partensky, F., Maréchal, ?., Nguyen, N.A., Doré, H., Ratin, M., Pitt, F.D., Scanlan, D.J., Six, C., 2018. Thermoacclimation and genome adaptation of the membrane lipidome in marine Synechococcus. Environmental Microbiology 20, 612-631. marine cyanobacteria of the genus Synechococcus are important primary producers, displaying a wide latitudinal distribution that is underpinned by diversification into temperature ecotypes. The physiological basis underlying these ecotypes is poorly known. In many organisms, regulation of membrane fluidity is crucial for acclimating to variations in temperature. Here, we reveal the detailed composition of the membrane lipidome of the model strain Synechococcus sp. WH7803 and its response to temperature variation. Unlike freshwater strains, membranes are almost devoid of C18, mainly containing C14 and C16 chains with no more than two unsaturations. In response to cold, we observed a rarely observed process of acyl chain shortening that likely induces membrane thinning, along with specific desaturation activities. Both of these mechanisms likely regulate membrane fluidity, facilitating the maintenance of efficient photosynthetic activity. A comprehensive examination of 53 Synechococcus genomes revealed clade-specific gene sets regulating membrane lipids. In particular, the genes encoding desaturase enzymes, which is a key to the temperature stress response, appeared to be temperature ecotype-specific, with some of them originating from lateral transfers. Our study suggests that regulation of membrane fluidity has been among the important adaptation processes for the colonization of different thermal niches by marine Synechococcus.Poggenburg, C., Mikutta, R., Schippers, A., Dohrmann, R., Guggenberger, G., 2018. Impact of natural organic matter coatings on the microbial reduction of iron oxides. Geochimica et Cosmochimica Acta 224, 223-248. (Fe) oxyhydroxides are important constituents of the soil mineral phase known to stabilize organic matter (OM) under oxic conditions. In an anoxic milieu, however, these Fe-organic associations are exposed to microbial reduction, releasing OM into soil solution. At present, only few studies have addressed the influence of adsorbed natural OM (NOM) on the reductive dissolution of Fe oxyhydroxides. This study therefore examined the impact of both the composition and concentration of adsorbed NOM on microbial Fe reduction with regard to (i) electron shuttling, (ii) complexation of Fe(II,III), (iii) surface site coverage and/or pore blockage, and (iv) aggregation. Adsorption complexes with varying carbon loadings were synthesized using different Fe oxyhydroxides (ferrihydrite, lepidocrocite, goethite, hematite, magnetite) and NOM of different origin (extracellular polymeric substances from Bacillus subtilis, OM extracted from soil Oi and Oa horizons). The adsorption complexes were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), N2 gas adsorption, electrophoretic mobility and particle size measurements, and OM desorption. Incubation experiments under anaerobic conditions were conducted for 16?days comparing two different strains of dissimilatory Fe(III)-reducing bacteria (Shewanella putrefaciens, Geobacter metallireducens). Mineral transformation during reduction was assessed via XRD and FTIR. Microbial reduction of the pure Fe oxyhydroxides was controlled by the specific surface area (SSA) and solubility of the minerals. For Shewanella putrefaciens, the Fe reduction of adsorption complexes strongly correlated with the concentration of potentially usable electron-shuttling molecules for NOM concentrations <2?mg C L?1, whereas for Geobacter metallireducens, Fe reduction depended on the particle size and thus aggregation of the adsorption complexes. These diverging results suggest that the influence of NOM on the stability of Fe-organic associations in soils cannot easily be assessed without considering the composition of the microbial soil community.Points, L.J., Taylor, J.W., Grizou, J., Donkers, K., Cronin, L., 2018. Artificial intelligence exploration of unstable protocells leads to predictable properties and discovery of collective behavior. Proceedings of the National Academy of Sciences 115, 885-890.: Exploring and understanding the emergence of complex behaviors is difficult even in “simple” chemical systems since the dynamics can rest on a knife edge between stability and instability. Herein, we study the complex dynamics of a simple protocell system, comprising four-component oil droplets in an aqueous environment using an automated platform equipped with artificial intelligence. The system autonomously selects and performs oil-in-water droplet experiments, and then records and classifies the behavior of the droplets using image recognition. The data acquired are then used to build predictive models of the system. Physical properties such as viscosity, surface tension, and density are related to behaviors, as well as to droplet behavioral niches, such as collective swarming.Abstract: Protocell models are used to investigate how cells might have first assembled on Earth. Some, like oil-in-water droplets, can be seemingly simple models, while able to exhibit complex and unpredictable behaviors. How such simple oil-in-water systems can come together to yield complex and life-like behaviors remains a key question. Herein, we illustrate how the combination of automated experimentation and image processing, physicochemical analysis, and machine learning allows significant advances to be made in understanding the driving forces behind oil-in-water droplet behaviors. Utilizing >7,000 experiments collected using an autonomous robotic platform, we illustrate how smart automation cannot only help with exploration, optimization, and discovery of new behaviors, but can also be core to developing fundamental understanding of such systems. Using this process, we were able to relate droplet formulation to behavior via predicted physical properties, and to identify and predict more occurrences of a rare collective droplet behavior, droplet swarming. Proton NMR spectroscopic and qualitative pH methods enabled us to better understand oil dissolution, chemical change, phase transitions, and droplet and aqueous phase flows, illustrating the utility of the combination of smart-automation and traditional analytical chemistry techniques. We further extended our study for the simultaneous exploration of both the oil and aqueous phases using a robotic platform. Overall, this work shows that the combination of chemistry, robotics, and artificial intelligence enables discovery, prediction, and mechanistic understanding in ways that no one approach could achieve alone.Pokrovsky, O.S., Karlsson, J., Giesler, R., 2018. Freeze-thaw cycles of Arctic thaw ponds remove colloidal metals and generate low-molecular-weight organic matter. Biogeochemistry 137, 321-336. boreal and arctic surface/inland waters contain sizeable reservoirs of dissolved organic matter (DOM) and trace elements (TE), which are subject to seasonal freezing. Specifically, shallow ponds and lakes in the permafrost zone often freeze solid, which can lead to transformations in the colloidal and dissolved fractions of DOM and TE. Here, we present results from experimental freeze-thaw cycles using iron (Fe)- and DOM-rich water from thaw ponds situated in Stordalen and Storflaket palsa mires in northern Sweden. After ten cycles of freezing, 85% of Fe and 25% of dissolved organic carbon (DOC) were removed from solution in circumneutral fen water (pH?6.9) but a much smaller removal of Fe and DOC (<?7%) was found in acidic bog water (pH?3.6). This removal pattern was consistent with initial supersaturation of fen water with respect to Fe hydroxide and a lack of supersaturation with any secondary mineral phase in the bog water. There was a nearly two- to threefold increase in the low-molecular-weight (LMW) fraction of organic carbon (OC) and several TEs caused by the repeated freeze-thaw cycles. Future increases in the freeze-thaw frequency of surface waters with climate warming may remove up to 25% of DOC in circumneutral organic-rich waters. Furthermore, an increase of LMW OC may result in enhanced carbon dioxide losses from aquatic ecosystems since this fraction is potentially more susceptible to biodegradation.Polidoro, A.d.S., Scapin, E., Lazzari, E., Silva, A.N., dos Santos, A.L., Caram?o, E.B., Jacques, R.A., 2018. Valorization of coffee silverskin industrial waste by pyrolysis: From optimization of bio-oil production to chemical characterization by GC?×?GC/qMS. Journal of Analytical and Applied Pyrolysis 129, 43-52. bean tegument (silverskin) is a by-product derived from the coffee roasting process. This residue has been discarded, which constitutes a serious environmental problem. The depletion of oil reserves and environmental issues promoted by the combustion of fossil fuels has generated interest in the use of biomass to obtain fuel and chemicals products. The liquid product obtained by biomass pyrolysis is commonly called bio-oil. Bio-oil is a complex mixture of compounds, and its detailed chemical characterization is necessary to prospect its potential uses. Therefore, this study optimized the final temperature of pyrolysis and N2 flow rate parameters for the pyrolysis of silverskin in a fixed bed reactor, by using a central composite design and response surface. The bio-oil chemical composition was evaluated by comprehensive two-dimensional gas chromatography coupled to rapid-scanning quadrupole mass spectrometry (GC?×?GC/qMS), combined with the use of standards and linear temperature-programmed retention indices (LTPRI). The optimal values ??calculated were 560?°C for the final pyrolysis temperature and 49?mL?min?1 for the N2 flow rate. The organic phase yield was 15.2% under these conditions. At the optimal conditions, 228 compounds were identified (90.1% of the sample chromatographic volume) in the organic phase. The major chemical class, in terms of volume percentage, were the phenols (26.70%), followed by nitrogen compounds (18.51%). In addition, it is worth mentioning the high representability of the saturated hydrocarbons (8.28%), unsaturated aliphatic (6.69%), and aromatics (7.77%), which together account for 22.74% of the sample chromatographic volume. These results showed that the silverskin bio-oil may have the potential use as a source of chemical inputs.Price, S.D.R., Keenleyside, A., Schwarcz, H.P., 2018. Testing the validity of stable isotope analyses of dental calculus as a proxy in paleodietary studies. Journal of Archaeological Science 91, 92-103. isotopic analyses (δ13C, δ15N) of dental calculus have been suggested as a proxy for the study of diet of ancient populations but questions about their validity have been raised. Here we test this question, introducing significant improvements in the analysis of δ13C and comparing our results for δ13C and δ15N of calculus with corresponding analyses of associated well-preserved bone which are widely believed to provide reliable paleodiet values. The content of organic material in calculus is decreased by ～75% compared with modern calculus, resulting in diagenetic changes to δ13C and δ15N of organic matter. Neither δ13C nor δ15N analyses of the organic component of calculus provide accurate estimates of paleodiet. Although δ15N values of dental calculus are correlated with δ15N values of bone collagen from the same individual, it is clear that they have been greatly affected by diagenesis, as shown by a correlation between C/N ratio and δ15N. The inorganic (mineral-bound) carbon component of calculus, analyzed separately from the organic component, gave δ13C values slightly offset from δ13C values of CO3 in bone mineral. Thus it alone appears to have potential as a dietary proxy.Prodhan, M.A.I., Yin, X., Kim, S., McClain, C., Zhang, X., 2018. Surface fitting for calculating the second dimension retention index in comprehensive two-dimensional gas chromatography mass spectrometry. Journal of Chromatography A 1539, 62-70. two-dimensional gas chromatography mass spectrometry (GC?×?GC–MS) has been widely used for analysis of volatile compounds. However, the second dimension retention index (I) of each compound is not widely used to aid compound identification owing to the limited accuracy of I calculation. We report a surface fitting approach to the calculation of I using n-alkanes (C7–C30) as references, where the second dimension retention time (2tR) and the second dimension column temperature (2Te) formed the X-Y plane and the I was the Z-axis to form the I surface. Compared to the conventional approach for calculating I using isovolatility curves, the surface fitting approach eliminated the construction of isovolatility curves for the reference compounds and gives better reproducibility. The goodness of the proposed surface fitting achieved R2?=?0.9999 and RMSE?=?6.1 retention index units (iu). Ten-fold cross validation demonstrated the surface fitting approach had a good predictability with average R2?=?0.9999 and RMSE?=?6.6 iu. The developed method was also applied to calculate the second dimension retention indices of compound standards in two commercial mixtures MegaMix A and MegaMix B. The mean standard deviation of the calculated I was only 1.6 iu for compounds in MegaMix A and 3.4 iu for compounds in MegaMix B. Compared with the literature results, the small value of standard deviation in the calculated retention index using surface fitting method shows that the surface fitting method has less measurement variability than the conventional isovolatility curve approach.Prost, K., Bradel, P.L., Lehndorff, E., Amelung, W., 2018. Steroid dissipation and formation in the course of farmyard manure composting. Organic Geochemistry 118, 47-57. are used as biomarkers for tracing faecal material in the environment, but their dissipation behaviour in the course of composting has remained unclear. To assess their stability, we tracked the fate of Δ5-sterols, 5α-stanols, 5β-stanols, epi-5β-stanols, stanones and bile acids after 0, 7, 14, 28, 56, 112 and 168?days and after 0 and 168?days of composting cattle and horse farmyard manure, respectively. After composting, extractable steroid content decreased by 93.8–99.9% for cattle manure and by 54.0–100% for horse manure relative to the initial amount. The loss was with 98.8–99.9%, particularly pronounced for bile acids in the cattle manure compost. Our findings challenge the assumption that bile acids are generally more resistant towards degradation than other steroids. Contrary to the bile acids, the Δ5-sterol content did not decrease constantly, but showed a temporary increase, pointing to a delayed release from straw (β-sitosterol, stigmasterol and cholesterol) or to temporary production by fungi (cholesterol). Similarly, there was no continued loss of cholesterol transformation products (5α-cholestanol, cholestanone and epicoprostanol); they either increased temporarily or showed delayed degradation. These changes in steroid patterns complicate the identification of compost as faecal matter by way of commonly used steroid ratios and stress the importance of additional bile acid analysis in geo-archaeological research. Nevertheless, slower dissipation and smaller relative loss of epi-5β-stanols vs. 5β-stanols increased the value of r?=?epi-5β-stigmastanol/5β-stigmastanol?+?epicoprostanol/coprostanol during composting and allowed differentiation between fresh farmyard manure, and immature and mature compost.Pu, W., Zhao, S., Wang, S., Wei, B., Yuan, C., Li, Y., 2018. Investigation into the migration of polymer microspheres (PMs) in porous media: Implications for profile control and oil displacement. Colloids and Surfaces A: Physicochemical and Engineering Aspects 540, 265-275. reduce the unwanted water and further enhance oil recovery, a profile control agent, named polymer microspheres (PMs), was synthesized by inverse emulsion polymerization and its physical properties including morphology, particle size distribution, dispersibility strength and hydration swelling property were thoroughly examined. The main goal of this paper was to investigate the migration behaviors of the PMs in porous media using visual micromodel, nuclear magnetic resonance (NMR) and core displacement tests. The visual images indicated the PMs could plug the high permeability area and divert the subsequently injected fluid to lower permeability area. Moreover, the PMs could re-migrate in the high permeability area and displace residual oil due to elastic deformation. The NMR results revealed that the PMs with low expansion rate and high elasticity generated higher swept volume and displacement efficiency, thus leading to higher oil recovery, compared to those having high expansion rate and low elasticity. It can be observed from oil-water relative permeability curves that compared with water flooding (WF), the oil-water isotonic point was shifted into higher water saturation and disproportionate permeability reduction (DPR) occurred during PMs flooding (PMF). Finally, the profile control and displacement mechanisms of PMs were proposed based on the experimental observations.Pudenzi, M.A., Santos, J.M., Wisniewski, A., Eberlin, M.N., 2018. Comprehensive characterization of asphaltenes by Fourier transform ion cyclotron resonance mass spectrometry precipitated under different n-alkanes solvents. Energy & Fuels 32, 1038-1046. are still problematic fractions and their composition is not fully unveiled as it relates to the original crude oil and the precipitation method. In this work, the composition of asphaltenes precipitated with n-heptane and n-pentane from ten crude oils from the Sergipe-Alagoas Basin were assessed by ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) using five ionization procedures (electrospray ionization (ESI), ESI(+) with formic acid, ESI(?) with ammonium hydroxide, and ESI(?) with tetramethylammonium hydroxide, and atmospheric pressure photoionization (APPI), APPI(+) and APPI(?)) in combination with a 7.2 T LTQ FT Ultra Thermo Fisher spectrometer. The purpose was to evaluate compositional differences between C5- and C7-asphaltenes according to the adopted ionization methodologies. Asphaltenes were compared as a function of heteroatomic composition and aromaticity. Chemometrics strategies were employed to evaluate the heteroatom classes of higher variation among the groups. Ions that were shared by the asphaltenes and the crude oils and between the ionization methods were also evaluated for similarity. Results showed that n-heptane asphaltenes are more aromatic than n-pentane asphaltenes, which in turn were found to be more acidic and to display a higher heteroatomic complexity. Principal component analysis and the evaluation of shared ions showed that APPI(±) is able to detected asphaltene ions directly from the whole crude oil. It was also found that the use of different ionization methods with and without additives is fundamental to obtain more comprehensive chemical profiles in terms of classes and their constituents for crude oils and their asphaltenes and that the specific n-alkane used to precipitate asphaltenes leads to different chemical profiles.Purcell, P.G., 2018. Re-imagining and re-imaging the development of the East African Rift. Petroleum Geoscience 24, 21-40. East African Rift (EAR) has fascinated and challenged the geological imagination since its discovery nearly a century ago. A new series of images showing the sequential development of faulting and volcanism along the Rift from 45?Ma to present offers a regional overview of that development. The EAR is the latest phase of the extensive Phanerozoic rifting of the East African continental plate, interwoven with the lithospheric fabrics knitted together during its complex Proterozoic past. South of 5° S, the EAR variously follows or cuts across the Karoo rift trends; north of 5° S, it is almost totally within new or reworked Neoproterozoic terranes, while the Karoo rifts are almost totally outside them. The compilations raise several aspects of rift development seemingly in need of re-imagining, including tight-fit reconstructions of the Gulf of Aden, and the projection of Mesozoic rifts from Yemen to Somalia. Overall, the rifting process does not accord well with a mechanistic paradigm and is better imagined within the Prigoginian paradigm, which accepts instability and disorder within natural processes such as mantle plumes. The structural complexity of Afar and its non-alignment with magnetic anomalies suggests that the seafloor spreading process is, in its beginnings at least, more chaos than order.Qi, Z., Abedini, A., Sharbatian, A., Pang, Y., Guerrero, A., Sinton, D., 2018. Asphaltene deposition during bitumen extraction with natural gas condensate and naphtha. Energy & Fuels 32, 1433-1439. bitumen extraction processes are alternatives to thermal processes with potential for improved economic and environmental performance. However, solvent interaction with bitumen commonly results in in situ asphaltene precipitation and deposition, which can hinder flow and reduce the process efficiency. Successful implementation requires one to select a solvent that improves recovery with minimal flow assurance problems. The majority of candidate industrial solvents are in the form of mixtures containing a wide range of hydrocarbon fractions, further complicating the selection process. In this study, we quantify the pore-scale asphaltene deposition using two commonly available solvent mixtures, natural gas condensate and naphtha, using a microfluidic platform. The results are also compared with those of two typical pure solvents, n-pentane and n-heptane, with all cases evaluated with both 50 and 100 μm pore-throat spacing. The condensate produced more asphaltenes and pore-space damage than the naphtha and exhibited deposition dynamics similar to that of pentane and heptane. This similarity is due to the presence of a large amount of light hydrocarbon fractions in condensate (～85 wt % of C5s–C7s) dictating the overall deposition dynamics. Naphtha, which contains heavier fractions (～70 wt % of C8s–C11s) and aromatic/naphthenic components, generated less asphaltenes and exhibited a slower deposition rate, resulting in less pore damage and overall better performance.Qin, S., Lu, Q., Li, Y., Wang, J., Zhao, Q., Gao, K., 2018. Relationships between trace elements and organic matter in coals. Journal of Geochemical Exploration 188, 101-110. modes of occurrence of trace elements (TEs) in coals are important for assessing the potential for economic extraction of valuable TEs (Ge, Ga, Li, REY, PGEs, etc.) and to determine the environmental risk of hazardous TEs (F, Cl, As, Cr, Cd, Pb, etc.). To date, associations of TEs with inorganic components (minerals) are well understood. However, information on the relationships of TEs with organic matter in coals is relatively limited. This review compares indirect and direct methods employed to investigate the modes of occurrence of TEs in coals, focusing on the associations of TEs with organic matter. Those TEs with a strong organic relationship are identified and detailed; they include Ge, U, Ga, REY, Be, B, As, Se, Cl, Br, and W. Other TEs weakly related with organic matter in coals are also detailed in the order of their periodic table groups. Finally, the influence of coal rank on the relationship of TEs with organic matter is discussed, and an inherent geochemical law, i.e., the element periodic law, is proposed to govern the relationship.Qiu, X., Yao, Y., Wang, H., Duan, Y., 2018. Live microbial cells adsorb Mg2+ more effectively than lifeless organic matter. Frontiers of Earth Science 12, 160-169. Mg2+ content is essential in determining different Mg-CaCO3 minerals. It has been demonstrated that both microbes and the organic matter secreted by microbes are capable of allocating Mg2+ and Ca2+ during the formation of Mg-CaCO3, yet detailed scenarios remain unclear. To investigate the mechanism that microbes and microbial organic matter potentially use to mediate the allocation of Mg2+ and Ca2+ in inoculating systems, microbial mats and four marine bacterial strains (Synechococcus elongatus, Staphylococcus sp., Bacillus sp., and Desulfovibrio vulgaris) were incubated in artificial seawater media with Mg/Ca ratios ranging from 0.5 to 10.0. At the end of the incubation, the morphology of the microbial mats and the elements adsorbed on them were analyzed using scanning electronic microscopy (SEM) and energy diffraction spectra (EDS), respectively. The content of Mg2+ and Ca2+ adsorbed by the extracellular polysaccharide substances (EPS) and cells of the bacterial strains were analyzed with atomic adsorption spectroscopy (AAS). The functional groups on the surface of the cells and EPS of S. elongatus were estimated using automatic potentiometric titration combined with a chemical equilibrium model. The results show that live microbial mats generally adsorb larger amounts of Mg2+ than Ca2+, while this rarely is the case for autoclaved microbial mats. A similar phenomenon was also observed for the bacterial strains. The living cells adsorb more Mg2+ than Ca2+, yet a reversed trend was observed for EPS. The functional group analysis indicates that the cell surface of S. elongatus contains more basic functional groups (87.24%), while the EPS has more acidic and neutral functional groups (83.08%). These features may be responsible for the different adsorption behavior of Mg2+ and Ca2+ by microbial cells and EPS. Our work confirms the differential Mg2+ and Ca2+ mediation by microbial cells and EPS, which may provide insight into the processes that microbes use to induce Mg-carbonate formation.Quatrini, R., Johnson, D.B., 2018. Microbiomes in extremely acidic environments: functionalities and interactions that allow survival and growth of prokaryotes at low pH. Current Opinion in Microbiology 43, 139-147. acidic environments have global distribution and can have natural or, increasingly, anthropogenic origins. Extreme acidophiles grow optimally at pH 3 or less, have multiple strategies for tolerating stresses that accompany high levels of acidity and are scattered in all three domains of the tree of life. Metagenomic studies have expanded knowledge of the diversity of extreme acidophile communities, their ecological networks and their metabolic potentials, both confirmed and inferred. High resolution compositional and functional profiling of these microbiomes have begun to reveal spatial diversity patterns at global, regional, local, zonal and micro-scales. Future integration of genomic and other meta-omic data will offer new opportunities to utilize acidic microbiomes and to engineer beneficial interactions within them in biotechnologies.Raanan, H., Pike, D.H., Moore, E.K., Falkowski, P.G., Nanda, V., 2018. Modular origins of biological electron transfer chains. Proceedings of the National Academy of Sciences 115, 1280-1285;.: There are no physical fossils of the original proteins at the beginning of life on Earth and phylogenetic approaches that infer the nature of the ancestral proteins from sequences and/or structures of extant molecules are of limited use over long time scales (e.g., billions of years). We analyzed the structures of proteins containing transition-metal cofactors, and identified four structural modules that comprise the diverse family of oxidoreductases, molecular nanomachines that are critical for electron transfer reactions that form the energetic basis of life. These structural modules are, in effect, relict “building blocks” of life that have descended through time with only minor modifications. Abstract: Oxidoreductases catalyze electron transfer reactions that ultimately provide the energy for life. A limited set of ancestral protein-metal modules are presumably the building blocks that evolved into this diverse protein family. However, the identity of these modules and their path to modern oxidoreductases is unknown. Using a comparative structural analysis approach, we identify a set of fundamental electron transfer modules that have evolved to form the extant oxidoreductases. Using transition metal-containing cofactors as fiducial markers, it is possible to cluster cofactor microenvironments into as few as four major modules: bacterial ferredoxin, cytochrome c, symerythrin, and plastocyanin-type folds. From structural alignments, it is challenging to ascertain whether modules evolved from a single common ancestor (homology) or arose by independent convergence on a limited set of structural forms (analogy). Additional insight into common origins is contained in the spatial adjacency network (SPAN), which is based on proximity of modules in oxidoreductases containing multiple cofactor electron transfer chains. Electron transfer chains within complex modern oxidoreductases likely evolved through repeated duplication and diversification of ancient modular units that arose in the Archean eon.Radhwani, M., Bechtel, A., Singh, V.P., Singh, B.D., Manna?-Tayech, B., 2018. Petrographic, palynofacies and geochemical characteristics of organic matter in the Saouef Formation (NE Tunisia): Origin, paleoenvironment, and economic significance. International Journal of Coal Geology 187, 114-130. lignite layers and carbonaceous shales are studied in order to reconstruct the origin and depositional environment of organic matter (OM), as well as to evaluate their economic potential. The study is based on organic compositions, bulk geochemical parameters, biomarker data, and carbon isotope composition of OM (δ13C). Lignite samples, collected next to the Saouef village, were macroscopically identified as stratified matrix coal or as humic coal. Rock Eval pyrolysis and the palynofacies analysis indicate the predominance of Type-III-IV kerogen (OM). The depositional environment fluctuated between terrestrial environments with a low water table to the limnic environment. The OM is derived from higher land plant remains (e.g. wood, root, bark) from a mixed vegetation including conifers and angiosperms, and emerged macrophytes. The dominance of huminite over liptinite and intertinite maceral groups, along with the phytoclasts, confirms the woody origin of the OM. A high bacterial activity is evidenced by the abundance of hopanoids in the extractable OM as well as by the amorphous OM content. The high measured TOC values exceeding 20 wt% in some samples may give an economic value of the organic layers of Saouef Formation. However, a Tmax < 435 °C and Rr < 0.5% induce the immaturity of the samples despite the presence of expelled bitumen in one sample.Radlinski, A.P., Mastalerz, M., 2018. Neutron scattering study of vitrinite: Insights into sub-micrometer inclusions in North American Carboniferous coals of bituminous rank. International Journal of Coal Geology 186, 145-154. of SANS and USANS measurements performed on a series of six vitrinite samples having vitrinite reflectance (Ro) values ranging from 0.55% (high volatile bituminous rank) to 1.28% (medium volatile bituminous rank) were analyzed. Experimental data were acquired for two sample forms: platelets cut parallel to the bedding and pellets made up of randomly oriented, nearly-monodisperse particles.Numerical analysis indicates the presence of sub-micron sized inclusions embedded in the organic matrix. For the lowest-rank vitrinites, the dominating inclusions are monodisperse are ~ 7–12 nm in diameter, and have concentrations of the order of 1017 cm? 3. Their shape is anisotropic, with the surface-to-volume ratio about three times larger than for a solid sphere.The higher-rank vitrinites contain much larger monodisperse inclusions having diameters of ~ 50 nm, concentrations of ~ 1014 cm? 3, large surface-to-volume ratios, and fuzzy interfaces with the organic matrix. Inclusions of a similar size and concentration are also present in the lowest-rank sample, but are much less frequent than the small inclusions. We provisionally interpret those objects as inclusions of mineral matter, most likely associated with original plant material. The internal specific surface area (SSA) calculated for the small mineral matter inclusions is ~ 100 m2/cm3 and for the large inclusions ~ 2 m2/cm3.Raghanti, M.A., Edler, M.K., Stephenson, A.R., Munger, E.L., Jacobs, B., Hof, P.R., Sherwood, C.C., Holloway, R.L., Lovejoy, C.O., 2018. A neurochemical hypothesis for the origin of hominids. Proceedings of the National Academy of Sciences 115, E1108-E1116 : Two factors vital to the human clade are our unique demographic success and our social facilities including language, empathy, and altruism. These have always been difficult to reconcile with individual reproductive success. However, the striatum, a region of the basal ganglia, modulates social behavior and exhibits a unique neurochemical profile in humans. The human signature amplifies sensitivity to social cues that encourage social conformity and affiliative behavior and could have favored provisioning and monogamy in emergent hominids, consilient with the simultaneous origin of upright walking and elimination of the sectorial canine. Such exceptional neurochemistry would have favored individuals especially sensitive to social cues throughout later human evolution and may account for cerebral cortical expansion and the emergence of language. Abstract: It has always been difficult to account for the evolution of certain human characters such as language, empathy, and altruism via individual reproductive success. However, the striatum, a subcortical region originally thought to be exclusively motor, is now known to contribute to social behaviors and “personality styles” that may link such complexities with natural selection. We here report that the human striatum exhibits a unique neurochemical profile that differs dramatically from those of other primates. The human signature of elevated striatal dopamine, serotonin, and neuropeptide Y, coupled with lowered acetylcholine, systematically favors externally driven behavior and greatly amplifies sensitivity to social cues that promote social conformity, empathy, and altruism. We propose that selection induced an initial form of this profile in early hominids, which increased their affiliative behavior, and that this shift either preceded or accompanied the adoption of bipedality and elimination of the sectorial canine. We further hypothesize that these changes were critical for increased individual fitness and promoted the adoption of social monogamy, which progressively increased cooperation as well as a dependence on tradition-based cultural transmission. These eventually facilitated the acquisition of language by elevating the reproductive advantage afforded those most sensitive to social cues. Rampino, M.R., Caldeira, K., 2018. Comparison of the ages of large-body impacts, flood-basalt eruptions, ocean-anoxic events and extinctions over the last 260 million years: a statistical study. International Journal of Earth Sciences 107, 601-606. studies have linked mass extinction events with the catastrophic effects of large-body impacts and flood-basalt eruptions, sometimes as competing explanations. We find that the ages of at least 10 out of a total of 11 documented extinction events over the last 260 Myr (12 out of 13 if we include two lesser extinction events) coincide, within errors, with the best-known ages of either a large impact crater (≥70?km diameter) or a continental flood-basalt eruption. The null hypothesis that this could occur by chance can be rejected with very high confidence (>99.999%). The ages of large impact craters correlate with recognized extinction events at ~36 (two impacts), 66, 145 and 215 Myr ago (and possibly an event at ~168 Myr ago), and the ages of continental flood basalts correlate with extinctions at 66, ~94, ~116, 183, 201, 252 and 259 Myr ago (and possibly at ~133 Myr ago). Furthermore, at least 7 periods of widespread anoxia in the oceans of the last 260 Myr coincide with the ages of flood-basalt eruptions (with 99.999% confidence), and are coeval with extinctions, suggesting causal connections. These statistical relationships argue that most mass extinction events are related to climatic catastrophes produced by the largest impacts and large-volume continental flood-basalt eruptions.Ransohoff, J.D., Wei, Y., Khavari, P.A., 2017. The functions and unique features of long intergenic non-coding RNA. Nature Reviews Molecular Cell Biology 19, 143. intergenic non-coding RNA (lincRNA) genes have diverse features that distinguish them from mRNA-encoding genes and exercise functions such as remodelling chromatin and genome architecture, RNA stabilization and transcription regulation, including enhancer-associated activity. Some genes currently annotated as encoding lincRNAs include small open reading frames (smORFs) and encode functional peptides and thus may be more properly classified as coding RNAs. lincRNAs may broadly serve to fine-tune the expression of neighbouring genes with remarkable tissue specificity through a diversity of mechanisms, highlighting our rapidly evolving understanding of the non-coding genome.Raposo, D., Clemente, I., Figueiredo, M., Vilar, A., Lorini, M.L., Frontalini, F., Martins, V., Belart, P., Fontana, L., Habib, R., Laut, L., 2018. Benthic foraminiferal and organic matter compounds as proxies of environmental quality in a tropical coastal lagoon: The Itaipu lagoon (Brazil). Marine Pollution Bulletin 129, 114-125. in the southeast coast of Brazil have experienced eutrophication due to the exponential increase of human population and sewage discharges. Living benthic foraminifera have demonstrated to be good bioindicators of such impacts. This study aims to evaluate the organic matter accumulation effects on the foraminiferal distribution in the Itaipu lagoon (Brazil). On the basis of the biotic and abiotic analyses, three sectors are identified. The Sector I, an inner area, is characterized by high dissolved oxygen values and foraminiferal species with preference for marine conditions, demonstrating the sea influence. The Sector II, in the mangrove margins, is associated to sandy sediment and biopolymers and mainly represented by euryhaline species. The Sector III is marked by low density or absence of living foraminifera and corresponds to a low quality organic matter enriched area (North, Southwest and Centre).Ravikumar, A.P., Wang, J., McGuire, M., Bell, C.S., Zimmerle, D., Brandt, A.R., 2018. “Good versus good enough?” Empirical tests of methane leak detection sensitivity of a commercial infrared camera. Environmental Science & Technology 52, 2368-2374., a key component of natural gas, is a potent greenhouse gas. A key feature of recent methane mitigation policies is the use of periodic leak detection surveys, typically done with optical gas imaging (OGI) technologies. The most common OGI technology is an infrared camera. In this work, we experimentally develop detection probability curves for OGI-based methane leak detection under different environmental and imaging conditions. Controlled single blind leak detection tests show that the median detection limit (50% detection likelihood) for FLIR-camera based OGI technology is about 20 g CH4/h at an imaging distance of 6 m, an order of magnitude higher than previously reported estimates of 1.4 g CH4/h. Furthermore, we show that median and 90% detection likelihood limit follows a power-law relationship with imaging distance. Finally, we demonstrate that real-world marginal effectiveness of methane mitigation through periodic surveys approaches zero as leak detection sensitivity improves. For example, a median detection limit of 100 g CH4/h is sufficient to detect the maximum amount of leakage that is possible through periodic surveys. Policy makers should take note of these limits while designing equivalence metrics for next-generation leak detection technologies that can trade sensitivity for cost without affecting mitigation priorities.Ray, D., Shukla, A.D., 2018. The Mukundpura meteorite, a new fall of CM chondrite. Planetary and Space Science 151, 149-154. is a new CM chondrite fell near Jaipur, Rajasthan, India on June 6, 2017 at 5:15 IST. The fall was observed by local villager. According to eyewitness, the meteorite was fragmented into several pieces once the object hit the ground. Based on petrography, mineralogy and bulk composition, Mukundpura is classified as CM2 chondrite. The chondrules are mainly similar to type I (Olivine: Fo99). Olivines are often found associated with pyroxene (Wo10-35En62-87Fs2-7) phenocryst. However, occurrences of forsteritic and fayalitic olivine (Fa58-71) as isolated mineral clast in matrix are not uncommon. Other types of chondrules include porphyritic pyroxene (En86Fs14) and barred olivine (Fa32.7±0.3) clast. Chondrules are commonly rimmed by fine-grained accretionary dust mantles. Phyllosilicates are the most dominant secondary mineral in matrix and largely associated with poorly characterised phases (PCP). FeO/SiO2 and S/SiO2 of PCP are 2.7 and 0.4 respectively. Other phases in matrix generally include calcite (pure CaCO3), Fe-Ni metal and sulphides. Spinel and perovskite occur occasionally as inclusions. The spherical or elliptical shaped metals (within chondrule or in isolated grains) are low-Ni type (kamacite <7.5 wt%) and resembles the solar Ni/Co ratio. However, Ni content in metal rarely exceeds 8.5 wt% (up to 23 wt%, taenite). Pyrrhotite (Fe ～62 wt%; S ～38 wt%) and pentlandite (Fe ～31–33 wt%, Ni ～28–32 wt%, S ～33 wt%)) are the common sulphides occur as isolated grains within the matrix, however, the former is the most dominant. The bulk chemical composition of Mukundpura is largely similar to other CM type chondrite (e.g. Paris CM). Based on petrography, we infer a modest aqueous alteration stage for Mukundpura while the effect of thermal metamorphism was negligible.Rees-Owen, R.L., Gill, F.L., Newton, R.J., Ivanovi?, R.F., Francis, J.E., Riding, J.B., Vane, C.H., Lopes dos Santos, R.A., 2018. The last forests on Antarctica: Reconstructing flora and temperature from the Neogene Sirius Group, Transantarctic Mountains. Organic Geochemistry 118, 4-14. deposits in the Transantarctic Mountains, Antarctica indicate that, despite the cold nature of the continent’s climate, a tundra ecosystem grew during periods of ice sheet retreat in the mid to late Neogene (17–2.5?Ma), 480?km from the South Pole. To date, palaeotemperature reconstruction has been based only on biological ranges, thereby calling for a geochemical approach to understanding continental climate and environment. There is contradictory evidence in the fossil record as to whether this flora was mixed angiosperm-conifer vegetation, or whether by this point conifers had disappeared from the continent. In order to address these questions, we have analysed, for the first time in sediments of this age, plant and bacterial biomarkers in terrestrial sediments from the Transantarctic Mountains to reconstruct past temperature and vegetation during a period of East Antarctic Ice Sheet retreat. From tetraether lipids (MBT′/CBT palaeothermometer), we conclude that the mean continental summer temperature was ca. 5?°C, in agreement with previous reconstructions. This was warm enough to have allowed woody vegetation to survive and reproduce even during the austral winter. Biomarkers from vascular plants indicate a low diversity and spatially variable flora consisting of higher plants, moss and algal mats growing in microenvironments in a glacial outwash system. Abietane-type compounds were abundant in some samples, indicating that conifers, most likely Podocarpaceae, grew on the Antarctic continent well into the Neogene. This is supported by the palynological record, but not the macrofossil record for the continent, and has implications for the evolution of vegetation on Antarctica.Reeves, C.V., 2018. The development of the East African margin during Jurassic and Lower Cretaceous times: a perspective from global tectonics. Petroleum Geoscience 24, 41-56. eastern margin of Africa resulted from the first successful trans-Gondwana rupture which retraced, in part, the earlier unsuccessful Karoo rift system. Widespread volcanism in southern Africa (182?Ma, Toarcian) presaged NW–SE-directed extension between East Gondwana and West Gondwana (Africa). Rifting turned progressively north–south in orientation, leading quickly to ocean growth off Somalia and off central Mozambique while, elsewhere, strike-slip within the stretched margin came to predominate. East Gondwana, including Madagascar, was demonstrably still intact at 151.4?Ma (M22, Kimmeridgian) but, as the two large continental fragments disengaged from each other, pure north–south movement became possible. After about 140?Ma (Berriasian), East Gondwana itself started to fragment off Western Australia but little separation occurred as far west as Madagascar before Aptian times (126.1?Ma). Nevertheless, the geometry of the Australia–India opening required that, in the interval 140?–?120?Ma, Madagascar–India pursued a path against Africa different from that of Antarctica. The arcuate Davie Fracture Zone, 1800?km in length, functioned as a pure strike-slip transform off the Tanzania–Mozambique coast for this fragment until the early Aptian demise of the Somali mid-ocean ridge. The active transform east of the Lebombo in southern Africa, meanwhile, relocated progressively eastwards, finally to outboard of the Mozambique Ridge at 136?Ma (Valanginian), leaving most if not all of the stretched continental crust and its volcanosedimentary load attached to Precambrian Africa.Rehfeld, K., Münch, T., Ho, S.L., Laepple, T., 2018. Global patterns of declining temperature variability from the Last Glacial Maximum to the Holocene. Nature 554, 356. in climate variability are as important for society to address as are changes in mean climate. Contrasting temperature variability during the Last Glacial Maximum and the Holocene can provide insights into the relationship between the mean state of the climate and its variability. However, although glacial–interglacial changes in variability have been quantified for Greenland, a global view remains elusive. Here we use a network of marine and terrestrial temperature proxies to show that temperature variability decreased globally by a factor of four as the climate warmed by 3–8 degrees Celsius from the Last Glacial Maximum (around 21,000 years ago) to the Holocene epoch (the past 11,500 years). This decrease had a clear zonal pattern, with little change in the tropics (by a factor of only 1.6–2.8) and greater change in the mid-latitudes of both hemispheres (by a factor of 3.3–14). By contrast, Greenland ice-core records show a reduction in temperature variability by a factor of 73, suggesting influences beyond local temperature or a decoupling of atmospheric and global surface temperature variability for Greenland. The overall pattern of reduced variability can be explained by changes in the meridional temperature gradient, a mechanism that points to further decreases in temperature variability in a warmer future.Remmers, I.M., Wijffels, R.H., Barbosa, M.J., Lamers, P.P., 2018. Can we approach theoretical lipid yields in microalgae? Trends in Biotechnology 36, 265-276. we approach theoretical lipid yields in microalgae? Yes: we can substantially reduce the gap between current and theoretical maximum yield. A realistic maximum is approximately 0.5 g triacylglycerol (TAG) per mol photons, about five times higher than what is currently achieved in outdoor cultivation. Achieving this realistic maximum will require several breakthroughs. First, outdoor operation typically has low yields, mainly caused by fluctuating insolation. Future adaptive control models will help increase these yields. Additionally, the lipid production capacity of currently used strains needs to increase. Powerful strain-specific molecular toolboxes are being developed, shifting the bottleneck towards understanding metabolism and identifying target genes. Finally, strains and processes should be improved concurrently to fully exploit the potential lipid production from microalgae.Retelletti Brogi, S., Ha, S.-Y., Kim, K., Derrien, M., Lee, Y.K., Hur, J., 2018. Optical and molecular characterization of dissolved organic matter (DOM) in the Arctic ice core and the underlying seawater (Cambridge Bay, Canada): Implication for increased autochthonous DOM during ice melting. Science of The Total Environment 627, 802-811. ice contains a large amount of dissolved organic matter (DOM), which can be released into the ocean once it melts. In this study, Arctic sea ice DOM was characterized for its optical (fluorescence) properties as well as the molecular sizes and composition via size exclusion chromatography and Fourier transformation ion cyclotron resonance mass spectrometry (FT-ICR MS). Ice cores were collected along with the underlying seawater samples in Cambridge Bay, an Arctic area experiencing seasonal ice formation. The ice core samples revealed a marked enrichment of dissolved organic carbon (DOC) compared to the seawater counterparts (up to 6.2 times greater). The accumulation can be attributed to in situ production by the autotrophic and heterotrophic communities. Fluorescence excitation emission matrices (EEMs) elaborated with parallel factor analysis (PARAFAC) evidenced the prevalence of protein-like substances in the ice cores, which likely results from in situ production followed by accumulation in the ice. Size exclusion chromatography further revealed the in situ production of all DOM size fractions, with the exception of the humic substance fraction. The majority of DOM in both the ice and seawater consists of low molecular weight compounds (<350?Da) probably derived by the microbial degradation/transformation of freshly produced DOM. Molecular characterization also supported the in situ production of DOM and highlighted the marked difference in molecular composition between sea ice and seawater. This study provides new insights into the possible role of sea ice DOM in the Arctic carbon cycle under climate change.Reygondeau, G., Guieu, C., Benedetti, F., Irisson, J.-O., Ayata, S.-D., Gasparini, S., Koubbi, P., 2017. Biogeochemical regions of the Mediterranean Sea: An objective multidimensional and multivariate environmental approach. Progress in Oceanography 151, 138-148. dividing the ocean, the aim is generally to summarise a complex system into a representative number of units, each representing a specific environment, a biological community or a socio-economical specificity. Recently, several geographical partitions of the global ocean have been proposed using statistical approaches applied to remote sensing or observations gathered during oceanographic cruises. Such geographical frameworks defined at a macroscale appear hardly applicable to characterise the biogeochemical features of semi-enclosed seas that are driven by smaller-scale chemical and physical processes. Following the Longhurst’s biogeochemical partitioning of the pelagic realm, this study investigates the environmental divisions of the Mediterranean Sea using a large set of environmental parameters. These parameters were informed in the horizontal and the vertical dimensions to provide a 3D spatial framework for environmental management (12 regions found for the epipelagic, 12 for the mesopelagic, 13 for the bathypelagic and 26 for the seafloor). We show that: (1) the contribution of the longitudinal environmental gradient to the biogeochemical partitions decreases with depth; (2) the partition of the surface layer cannot be extrapolated to other vertical layers as the partition is driven by a different set of environmental variables. This new partitioning of the Mediterranean Sea has strong implications for conservation as it highlights that management must account for the differences in zoning with depth at a regional scale.Richardson, I.A., Hartwig, J.W., Leachman, J.W., 2018. Experimental PρT-x measurements of liquid methane-ethane-nitrogen mixtures. Fluid Phase Equilibria 462, 38-43. is designing an unmanned submarine to explore the hydrocarbon rich seas of Saturn's moon Titan. Titan is the only known celestial body in our solar system other than Earth with stable liquid seas on its surface. The thermodynamic properties of Titan's seas have not been well characterized. This work investigates the solubility of nitrogen in varying liquid methane-ethane compositions and the effects of dissolved nitrogen on the density of the sea. Twenty-one pressure-density-temperature-composition (PρT-x) measurements are presented from 92?K to 96?K for pressures from 1?bar to 11?bar for varying compositions of methane, ethane, and nitrogen. These measurements are being used to aid in thermodynamic modeling of the Titan seas as well as the design of the Titan Submarine.Ristic, N.D., Djokic, M.R., Delbeke, E., Gonzalez-Quiroga, A., Stevens, C.V., Van Geem, K.M., Marin, G.B., 2018. Compositional characterization of pyrolysis fuel oil from naphtha and vacuum gas oil. Energy & Fuels 32, 1276-1286. cracking of crude oil fractions gives rise to substantial amounts of a heavy liquid product referred to as pyrolysis fuel oil (PFO). To evaluate the potential use of PFO for production of value-added chemicals, a better understanding of the composition is needed. Therefore, two PFO’s derived from naphtha (N-PFO) and vacuum gas oil (V-PFO) were characterized using elemental analysis, SARA fractionation, nuclear magnetic resonance (NMR) spectroscopy, and comprehensive two-dimensional gas chromatography (GC × GC) coupled to a flame ionization detector (FID) and time-of-flight mass spectrometer (TOF-MS). Both samples are highly aromatic, with molar hydrogen-to-carbon (H/C) ratios lower than 1 and with significant content of compounds with solubility characteristics typical for asphaltenes and coke (i.e. n-hexane insolubles). The molar H/C ratio of V-PFO is lower than the one measured for N-PFO, as expected from the lower molar H/C ratio of the VGO. On the other hand, the content of n-hexane insolubles is lower in V-PFO compared to the one in N-PFO (i.e., 10.3 ± 0.2 wt % and 19.5 ± 0.5 wt %, respectively). This difference is attributed to the higher reaction temperature applied during naphtha steam cracking, which promotes the formation of poly aromatic cores and at the same time scission of aliphatic chains. The higher concentrations of purely aromatic molecules present in N-PFO is confirmed via NMR and GC × GC–FID/TOF-MS. The dominant chemical family in both samples are diaromatics, with a concentration of 28.6 ± 0.1 wt % and 27.8 ± 0.1 wt % for N-PFO and V-PFO, respectively. Therefore, extraction of valuable chemical industry precursors such as diaromatics and specifically naphthalene is considered as a potential valorization route. On the other hand, hydro-conversion is required to improve the quality of the PFO’s before exploiting them as a commercial fuel.Rivas, M., Becerra, A., Lazcano, A., 2018. On the early evolution of catabolic pathways: A comparative genomics approach. I. The cases of glucose, ribose, and the nucleobases catabolic routes. Journal of Molecular Evolution 86, 27-46. with the large corpus of published work devoted to the study of the origin and early development of anabolism, little attention has been given to the discussion of the early evolution of catabolism in spite of its significance. In the present study, we have used comparative genomics to explore the evolution and phylogenetic distribution of the enzymes that catalyze the extant catabolic pathways of the monosaccharides glucose and ribose, as well as those of the nucleobases adenine, guanine, cytosine, uracil, and thymine. Based on the oxygen dependence of the enzymes, their conservation, and evolution, we speculate on the relative antiquity of the pathways. Our results allow us to suggest which catabolic pathways and enzymes may have already been present in the last common ancestor. We conclude that the enzymatic degradations of ribose, as well as those of purines adenine and guanine, are among the most ancient catabolic pathways which can be traced by protein-based methodologies.Roberts, P., Fernandes, R., Craig, O.E., Larsen, T., Lucquin, A., Swift, J., Zech, J., 2018. Calling all archaeologists: guidelines for terminology, methodology, data handling, and reporting when undertaking and reviewing stable isotope applications in archaeology. Rapid Communications in Mass Spectrometry 32, 361-372. isotope analysis has been utilized in archaeology since the 1970s, yet standardized protocols for terminology, sampling, pretreatment evaluation, calibration, quality assurance and control, data presentation, and graphical or statistical treatment still remain lacking in archaeological applications. Here, we present recommendations and requirements for each of these in the archaeological context of: bulk stable carbon and nitrogen isotope analysis of organics; bulk stable carbon and oxygen isotope analysis of carbonates; single compound stable carbon and nitrogen isotope analysis on amino acids in collagen and keratin; and single compound stable carbon and hydrogen isotope analysis on fatty acids. The protocols are based on recommendations from the Commission on Isotopic Abundances and Atomic Weights of the International Union of Pure and Applied Chemistry (IUPAC) as well as an expanding geochemical and archaeological science experimental literature. We hope that this will provide a useful future reference for authors and reviewers engaging with the growing number of stable isotope applications and datasets in archaeology.Robinson, K.N., Steven, R.T., Bunch, J., 2018. Matrix optical absorption in UV-MALDI MS. Journal of The American Society for Mass Spectrometry 29, 501-511. ultraviolet matrix-assisted laser desorption/ionization mass spectrometry (UV-MALDI MS) matrix compound optical absorption governs the uptake of laser energy, which in turn has a strong influence on experimental results. Despite this, quantitative absorption measurements are lacking for most matrix compounds. Furthermore, despite the use of UV-MALDI MS to detect a vast range of compounds, investigations into the effects of laser energy have been primarily restricted to single classes of analytes. We report the absolute solid state absorption spectra of the matrix compounds α-cyano-4-hydroxycinnamic acid (CHCA), para-nitroaniline (PNA), 2-mercaptobenzothiazole (MBT), 2,5-dihydroxybenzoic acid (2,5-DHB), and 2,4,6-trihydroxyacetophenone (THAP). The desorption/ionization characteristics of these matrix compounds with respect to laser fluence was investigated using mixed systems of matrix with either angiotensin II, PC(34:1) lipid standard, or haloperidol, acting as representatives for typical classes of analyte encountered in UV-MALDI MS. The first absolute solid phase spectra for PNA, MBT, and THAP are reported; additionally, inconsistencies between previously published spectra for CHCA are resolved. In light of these findings, suggestions are made for experimental optimization with regards to matrix and laser wavelength selection. The relationship between matrix optical cross-section and wavelength-dependant threshold fluence, fluence of maximum ion yield, and R, a new descriptor for the change in ion intensity with fluence, are described. A matrix cross-section of 1.3 × 10–17 cm–2 was identified as a potential minimum for desorption/ionization of analytes.Robu, M., Wynn, J.G., Mirea, I.C., Petculescu, A., Kenesz, M., Pu?ca?, C.M., Vlaicu, M., Trinkaus, E., Constantin, S., 2018. The diverse dietary profiles of MIS 3 cave bears from the Romanian Carpathians: insights from stable isotope (δ13C and δ15N) analysis. Palaeontology 61, 209-219. Pleistocene European cave bears (Ursus spelaeus) have been considered to be largely vegetarian, although stable isotope data (δ13C and δ15N values) from the Romanian Carpathians has suggested considerable dietary variation. Here we evaluate previous and additional adult cave bear isotopic data from four Marine Isotope Stage 3 (MIS 3) sites in the Carpathians. Pe?tera Ur?ilor (N = 35), Pe?tera Cioclovina (N = 32), Pe?tera Muierilor (N = 8), and Pe?tera cu Oase (N = 72) provide both a dichotomy between samples suggesting vegetarian diets (from Cioclovina and Muierilor) and more omnivorous diets (from Ur?ilor and Oase), and considerable isotopic variation within samples from each site. While an inference of a strictly vegetarian diet may apply to groups that lived in ecosystems which restricted the available animal protein for these large ursids, the within and between sample isotopic variation among the Carpathian cave bears indicates considerable flexibility in their sources of protein and hence in their dietary regimes. In addition, developmental assessment of Cioclovina isotopic profiles (neonates, juveniles, sub-adults and adults) provides patterns of transfer of stable isotope signatures throughout immature life for both δ13C and δ15N (increase and decrease, respectively), whereas those from Ur?ilor show little developmental shift.Rocha, J.A., Baydak, E.N., Yarranton, H.W., 2018. What fraction of the asphaltenes stabilizes water-in-bitumen emulsions? Energy & Fuels 32, 1440-1450. is hypothesized that only a fraction of the asphaltenes acts to stabilize emulsions and that this fraction consists of the most self-associated (least soluble) asphaltenes. To test the hypothesis, the effects of removing the least soluble versus the most interfacially adsorbed asphaltenes on emulsion stability, film properties, and mass surface coverage were compared. The least soluble asphaltenes were removed by precipitation from solutions of asphaltenes in heptane and toluene. The most adsorbed asphaltenes were removed by separating an asphaltene-stabilized emulsion from its continuous phase. Brine-in-oil emulsions were prepared using organic phases of 10 g/L of the residual asphaltene fractions from the supernatant or continuous phase. The stability of the emulsions was assessed in terms of percentage of water resolved after repeated treatment cycles involving heating at 60 °C and centrifugation at 3500 rpm. The three asphaltenes examined were extracted from a mined oil sand bitumen, a bitumen from a cyclic steam process, and a bitumen from a SAGD process. Only some of the species in the asphaltenes were found to strongly stabilize emulsion, and the size of this fraction ranged from 2% to >65% in the three samples of this study. The most adsorbed, highly stabilizing material tended to be concentrated in the least soluble fraction of the asphaltenes, consistent with the proposed hypothesis. The emulsion stability data were generally consistent with a previously observed threshold of 5 mg/m2 asphaltene surface coverage for stable emulsions. Fractionating the asphaltenes eventually removed enough of the self-associated material that the surface coverage dropped below the threshold and unstable emulsions were observed.Rodrigues, ?.V.A., Silva, S.R.C., Rom?o, W., Castro, E.V.R., Filgueiras, P.R., 2018. Determination of crude oil physicochemical properties by high-temperature gas chromatography associated with multivariate calibration. Fuel 220, 389-395. the physicochemical properties of petroleum is important for rapid decision-making during the production process. True boiling point (TBP) curve is the most important parameter in the petroleum characterization. However, the TBP can be estimated by high temperature gas chromatography (HTGC). In this paper, the HTGC technique associated with PLS regression was used to estimate API gravity, kinematic viscosity, pour point, carbon residue, saturated and aromatic content in crude oil. We use 98 samples with API gravity ranging from 11.4 to 54.0. Afterwards the developed methods were applied in nine samples from a field of production of the Brazilian coast. PLS model for API gravity, carbon residue, saturates and aromatics contents show root mean square error of prediction (RMSEP) set of 1.7, 0.83?wt%, 6.76?wt% and 4.05?wt% respectively. These models were applied to the nine samples and presented an exact equivalent to the models developed. The models for logarithm of kinematic viscosity and pour point show RMSEP of 0.31 and 12?°C respectively. Furthermore, tests applied in all models for evaluating the presence of systematic and trend errors indicate that there are no significant evidences of the presence of these types of error in the residues, at significance level of 5%.R?hnisch, H.E., Eriksson, J., Müllner, E., Agback, P., Sandstr?m, C., Moazzami, A.A., 2018. AQuA: An automated quantification algorithm for high-throughput NMR-based metabolomics and its application in human plasma. Analytical Chemistry 90, 2095-2102. key limiting step for high-throughput NMR-based metabolomics is the lack of rapid and accurate tools for absolute quantification of many metabolites. We developed, implemented, and evaluated an algorithm, AQuA (Automated Quantification Algorithm), for targeted metabolite quantification from complex 1H NMR spectra. AQuA operates based on spectral data extracted from a library consisting of one standard calibration spectrum for each metabolite. It uses one preselected NMR signal per metabolite for determining absolute concentrations and does so by effectively accounting for interferences caused by other metabolites. AQuA was implemented and evaluated using experimental NMR spectra from human plasma. The accuracy of AQuA was tested and confirmed in comparison with a manual spectral fitting approach using the ChenomX software, in which 61 out of 67 metabolites quantified in 30 human plasma spectra showed a goodness-of-fit (r2) close to or exceeding 0.9 between the two approaches. In addition, three quality indicators generated by AQuA, namely, occurrence, interference, and positional deviation, were studied. These quality indicators permit evaluation of the results each time the algorithm is operated. The efficiency was tested and confirmed by implementing AQuA for quantification of 67 metabolites in a large data set comprising 1342 experimental spectra from human plasma, in which the whole computation took less than 1 s.Rolison, J.M., Stirling, C.H., Middag, R., Gault-Ringold, M., George, E., Rijkenberg, M.J.A., 2018. Iron isotope fractionation during pyrite formation in a sulfidic Precambrian ocean analogue. Earth and Planetary Science Letters 488, 1-13. chemical response of the Precambrian oceans to rising atmospheric O2 levels remains controversial. The iron isotope signature of sedimentary pyrite is widely used to trace the microbial and redox states of the ocean, yet the iron isotope fractionation accompanying pyrite formation in nature is difficult to constrain due to the complexity of the pyrite formation process, difficulties in translating the iron isotope systematics of experimental studies to natural settings, and insufficient iron isotope datasets for natural euxinic (i.e. anoxic and sulfidic) marine basins where pyrite formation occurs. Herein we demonstrate, that a large, permil-level shift in the isotope composition of dissolved iron occurs in the Black Sea euxinic water column during syngenetic pyrite formation. Specifically, iron removal to syngenetic pyrite gives rise to an iron isotope fractionation factor between Fe(II) and FeS2 of 2.75 permil (‰), the largest yet reported for reactions under natural conditions that do not involve iron redox chemistry. These iron isotope systematics offer the potential to generate permil-level shifts in the sedimentary pyrite iron isotope record due to partial drawdown of the oceanic iron inventory. The implication is that the iron stable isotope signatures of sedimentary pyrites may record fundamental regime shifts between pyrite formation under sulfur-limited conditions and pyrite formation under iron-limited conditions. To this end, the iron isotope signatures of sedimentary pyrite may best represent the extent of euxinia in the past global ocean, rather than its oxygenation state. On this basis, the reinterpreted sedimentary pyrite Fe isotope record suggests a fundamental shift towards more sulfidic oceanic conditions coincident with the ‘Great Oxidation Event’ around 2.3 billion years ago. Importantly, this does not require the chemical state of the ocean to shift from mainly de-oxygenated to predominantly oxygenated in parallel with the permanent rise in atmospheric oxygen, contrary to other interpretations based on iron isotope systematics.Rontani, J.-F., Belt, S.T., Amiraux, R., 2018. Biotic and abiotic degradation of the sea ice diatom biomarker IP25 and selected algal sterols in near-surface Arctic sediments. Organic Geochemistry 118, 73-88. organic geochemical IP25 (Ice Proxy with 25 carbon atoms) has been used as a proxy for Arctic sea ice in recent years. To date, however, the role of degradation of IP25 in Arctic marine sediments and the impact that this may have on palaeo sea ice reconstruction based on this biomarker have not been investigated in any detail. Here, we show that IP25 may be susceptible to autoxidation in near-surface oxic sediments. To arrive at these conclusions, we first subjected a purified sample of IP25 to autoxidation in the laboratory and characterised the oxidation products using high resolution gas chromatography–mass spectrometric methods. Most of these IP25 oxidation products were also detected in near-surface sediments collected from Barrow Strait in the Canadian Arctic, although their proposed secondary oxidation and the relatively lower abundances of IP25 in other sediments probably explain why we were not able to detect them in material from other parts of the region. A rapid decrease in IP25 concentration in some near-surface Arctic marine sediments, including examples presented here, may potentially be attributed to at least partial degradation, especially for sediment cores containing relatively thick oxic layers representing decades or centuries of deposition. An increase in the ratio of two common phytoplanktonic sterols – epi-brassicasterol and 24-methylenecholesterol – provides further evidence for such autoxidation reactions given the known enhanced reactivity of the latter to such processes reported previously. In addition, we provide some evidence that biodegradation processes also act on IP25 in Arctic sediments. The oxidation products identified in the present study will need to be quantified more precisely in downcore records in the future before the effects of degradation processes on IP25-based palaeo sea ice reconstruction can be fully understood. In the meantime, a brief overview of some previous investigations of IP25 in relatively shallow Arctic marine sediments suggests that overlying climate conditions were likely dominant over degradation processes, as evidenced from often increasing IP25 concentration downcore, together with positive relationships to known sea ice conditions.Roullier-Gall, C., Signoret, J., Hemmler, D., Witting, M.A., Kanawati, B., Sch?fer, B., Gougeon, R.D., Schmitt-Kopplin, P., 2018. Usage of FT-ICR-MS metabolomics for characterizing the chemical signatures of barrel-aged whisky. Frontiers in Chemistry 6, 29. doi: 10.3389/fchem.2018.00029. can be described as a complex matrix integrating the chemical history from the fermented cereals, the wooden barrels, the specific distillery processes, ageing and environmental factors. In this study, using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), we analysed 150 whisky samples from 49 different distilleries, 7 countries, and ranging from 1 day new make spirit to 43 years of maturation with different types of barrel. Chemometrics revealed the unexpected impact of the wood history on the distillate?s composition during barrel ageing, regardless of the whisky origin. Flavonols, oligolignols and fatty acids are examples of important chemical signatures for Bourbon casks, whereas a high number of polyphenol glycosides, including for instance quercetin-glucuronide or myricetin-glucoside as potential candidates, and carbohydrates would discriminate Sherry casks. However, the comparison of barrel aged rums and whiskies revealed specific signatures, highlighting the importance of the initial composition of the distillate and the distillery processes.Roush, D., Couradeau, E., Guida, B., Neuer, S., Garcia-Pichel, F., 2018. A new niche for anoxygenic phototrophs as endoliths. Applied and Environmental Microbiology 84, Article e02055-17.: Anoxygenic phototrophic bacteria (APBs) occur in a wide range of aquatic habitats, from hot springs to freshwater lakes and intertidal microbial mats. Here, we report the discovery of a novel niche for APBs: endoliths within marine littoral carbonates. In a study of 40 locations around Isla de Mona, Puerto Rico, and Menorca, Spain, 16S rRNA high-throughput sequencing of endolithic community DNA revealed the presence of abundant phylotypes potentially belonging to well-known APB clades. An ad hoc phylogenetic classification of these sequences enabled us to refine the assignments more stringently. Even then, all locations contained such putative APBs, often reaching a significant proportion of all phototrophic sequences. In fact, in some 20% of samples, their contribution exceeded that of oxygenic phototrophs, previously regarded as the major type of endolithic microbe in carbonates. The communities contained representatives of APBs in the Chloroflexales, various proteobacterial groups, and Chlorobi. The most abundant phylotypes varied with geography: on Isla de Mona, Roseiflexus and Chlorothrix-related phylotypes dominated, whereas those related to Erythrobacter were the most common in Menorca. The presence of active populations of APBs was corroborated through an analysis of photopigments: bacteriochlorophylls were detected in all samples, bacteriochlorophyll c and a being most abundant. We discuss the potential metabolism and geomicrobial roles of endolithic APBs. Phylogenetic inference suggests that APBs may be playing a role as photoheterotrophs, adding biogeochemical complexity to our understanding of such communities. Given the global extent of coastal carbonate platforms, they likely represent a very large and unexplored habitat for APBs. Importance: Endolithic microbial communities from carbonates, which have been explored for over 2 centuries in predominantly naturalistic studies, were thought to be primarily composed of eukaryotic algae and cyanobacteria. Our report represents a paradigm shift in this regard, at least for the marine environment, demonstrating the presence of ubiquitous and abundant populations of APBs in this habitat. It raises questions about the role of these organisms in the geological dynamics of coastal carbonates, including coral reefs. Rudmin, M., Roberts, A.P., Horng, C.-S., Mazurov, A., Savinova, O., Ruban, A., Kashapov, R., Veklich, M., 2018. Ferrimagnetic iron sulfide formation and methane venting across the Paleocene-Eocene Thermal Maximum in shallow marine sediments, ancient West Siberian Sea. Geochemistry, Geophysics, Geosystems 19, 21-42. of ferrimagnetic iron sulfide minerals (greigite and monoclinic pyrrhotite) occurred across the Paleocene-Eocene Thermal Maximum (PETM) within the Bakchar oolitic ironstone in southeastern Western Siberia. Co-occurrence of these minerals is associated with diagenetic environments that support anaerobic oxidation of methane, which has been validated by methane fluid inclusion analysis in the studied sediments. In modern settings, such ferrimagnetic iron sulfide formation is linked to upward methane diffusion in the presence of minor dissolved sulfide ions. The PETM was the most extreme Cenozoic global warming event and massive methane mobilization has been proposed as a major contributor to the globally observed warming and carbon isotope excursion associated with the PETM. The studied sediments provide rare direct evidence for methane mobilization during the PETM. Magnetic iron sulfide formation associated with methanogenesis in the studied sediments can be explained by enhanced local carbon burial across the PETM. While there is no strong evidence to link local methane venting with more widespread methane mobilization and global warming, the magnetic, petrographic, and geochemical approach used here is applicable to identifying authigenic minerals that provide telltale signatures of methane mobility that can be used to assess methane formation and mobilization through the PETM and other hyperthermal climatic events.Rui, Z., Wang, X., Zhang, Z., Lu, J., Chen, G., Zhou, X., Patil, S., 2018. A realistic and integrated model for evaluating oil sands development with Steam Assisted Gravity Drainage technology in Canada. Applied Energy 213, 76-91. sands resource is the third largest oil reserve, and 70% of the oil sands are in Canada. The emerging of Steam Assisted Gravity Drainage technology has made the commercial development of oil sands economically feasible. However, with the recent oil price crash, the development of oil sands has faced an uphill battle. A realistic and integrated evaluation model is highly needed to overcome difficulties from the low oil price and provide meaningful and valuable information for operators as well as investors to make the right decision. The existing evaluation models have considerable limitations (i.e., the incapability of evaluating integrated oil sands development with Steam Assisted Gravity Drainage technology, the lack of investigation into the input parameters with historical data, and ignoring the effect of the subsurface reservoir, etc.). This study developed an integrated evaluation model through the analyses of a significant amount of actual historical data. This integrated model includes six subcomponent models, ranging from the subsurface reservoir to infield flowline. Data from 35 Canadian oil sands development with 15 internal and external parameters were collected and investigated. The oil price effect was analyzed and quantified through simulations. The breakeven Western Canada Select oil price of $39/bbl. (equal to the West Texas Intermediate oil price of $55/bbl.) and other key price points and distributions were identified. Also, the top seven geological and technical parameters that contribute 86% of the net present value variations were identified and investigated. These quantified effects of external and internal parameters are useful findings for decision making. Considering various price scenarios and uncertainties of the input parameters, this study has concluded that developing oil sands resources with the Steam Assisted Gravity Drainage technology is economically feasible and socially beneficial after we take all stakeholder interests into consideration, which is true even with the sustainable and realistic oil price in the foreseeable future.Rummel, J.D., Conley, C.A., 2018. Inadvertently finding earth contamination on Mars should not be a priority for anyone. Astrobiology 18, 108-115. article. No abstractSakurovs, R., Koval, L., Grigore, M., Sokolova, A., de Campo, L., Rehm, C., 2018. Nanostructure of cokes. International Journal of Coal Geology 188, 112-120. eight cokes made from Australian coals and prepared under a range of experimental conditions were examined using Small Angle Neutron Scattering (SANS) and Ultra Small Angle Neutron Scattering (USANS) to determine the size distribution of all of their pores and also pores inaccessible to deuterated toluene (closed pores) in the size range 1 to 1000?nm radius. The main findings were that in all cokes, even those made from relatively inertinite-rich coals, nearly all pores of <5?nm radius were closed and >70% of the pores of 1000?nm in radius or larger were open. At intermediate pore sizes, the fraction of open pores was highly variable, with cokes made from inertinite-rich coals having more open pores. For all cokes made from coals sourced in Queensland, Australia, the number of open pores increased linearly with increasing inertinite content of the original coal and was not strongly affected by rank over the range investigated (0.9–1.3% mean maximum vitrinite reflectance). In contrast, all of the cokes made from the coals from the Illawarra region, New South Wales, Australia, had less than half the number of total or open pores than the other cokes. The number of pores of <5?nm radius decreased with increasing rank of the starting coal and was not strongly affected by the starting maceral composition or region of origin. The ratio of number of pores in cokes made from inertinite-rich concentrates to those made from the corresponding vitrinite concentrate from the same coal varied with pore size and was greatest at around 100?nm pore radius. The number of pores in cokes at all sizes below 1000?nm was largely unaffected by the bulk density of the charge, oven size or method of quenching. The insensitivity of numbers of nanometre-sized pores in coke to coke preparation conditions can explain why increasing the bulk density of a coal charge may increase coke strength but will have much less effect on coke reactivity to carbon dioxide.Sakurovs, R., Koval, L., Grigore, M., Sokolova, A., Ruppert, L.F., Melnichenko, Y.B., 2018. Nanometre-sized pores in coal: Variations between coal basins and coal origin. International Journal of Coal Geology 186, 126-134. have used small angle neutron scattering (SANS) to investigate the differences in methane and hexane penetration in pores in bituminous coal samples from the U.S., Canada, South Africa, and China, and maceral concentrates from Australian coals. This work is an extension of previous work that showed consistent differences between the extent of penetration by methane into 10–20 nm size pores in inertinite in bituminous coals from Australia, North America and Poland.In this study we have confirmed that there are differences in the response of inertinite to methane and hexane penetration in coals sourced from different coal basins. Inertinite in Permian Australian coals generally has relatively high numbers of pores in the 2.5–250 nm size range and the pores are highly penetrable by methane and hexane; coals sourced from Western Canada had similar penetrability to these Australian coals. However, the penetrability of methane and hexane into inertinite from the Australian Illawarra Coal Measures (also Permian) is substantially less than that of the other Australian coals; there are about 80% fewer 12 nm pores in Illawarra inertinite compared to the other Australian coals examined. The inertinite in coals sourced from South Africa and China had accessibility intermediate between the Illawarra coals and the other Australian coals.The extent of hexane penetration was 10–20% less than CD4 penetration into the same coal and this difference was most pronounced in the 5–50 nm pore size range. Hexane and methane penetrability into the coals showed similar trends with inertinite content.The observed variations in inertinite porosity between coals from different coal regions and coal basins may explain why previous studies differ in their observations of the relationships between gas sorption behavior, permeability, porosity, and maceral composition. These variations are not simply a demarcation between Northern and Southern Hemisphere coals.Sallstedt, T., Bengtson, S., Broman, C., Crill, P.M., Canfield, D.E., 2018. Evidence of oxygenic phototrophy in ancient phosphatic stromatolites from the Paleoproterozoic Vindhyan and Aravalli Supergroups, India. Geobiology 16, 139-159. microbiotas are rare in the early rock record, limiting the type of ecological information extractable from ancient microbialites. In the absence of body fossils, emphasis may instead be given to microbially derived features, such as microbialite growth patterns, microbial mat morphologies, and the presence of fossilized gas bubbles in lithified mats. The metabolic affinity of micro-organisms associated with phosphatization may reveal important clues to the nature and accretion of apatite-rich microbialites. Stromatolites from the 1.6 Ga Chitrakoot Formation (Semri Group, Vindhyan Supergroup) in central India contain abundant fossilized bubbles interspersed within fine-grained in situ-precipitated apatite mats with average δ13Corg indicative of carbon fixation by the Calvin cycle. In addition, the mats hold a synsedimentary fossil biota characteristic of cyanobacterial and rhodophyte morphotypes. Phosphatic oncoid cone-like stromatolites from the Paleoproterozoic Aravalli Supergroup (Jhamarkotra Formation) comprise abundant mineralized bubbles enmeshed within tufted filamentous mat fabrics. Construction of these tufts is considered to be the result of filamentous bacteria gliding within microbial mats, and as fossilized bubbles within pristine mat laminae can be used as a proxy for oxygenic phototrophy, this provides a strong indication for cyanobacterial activity in the Aravalli mounds. We suggest that the activity of oxygenic phototrophs may have been significant for the formation of apatite in both Vindhyan and Aravalli stromatolites, mainly by concentrating phosphate and creating steep diurnal redox gradients within mat pore spaces, promoting apatite precipitation. The presence in the Indian stromatolites of alternating apatite-carbonate lamina may result from local variations in pH and oxygen levels caused by photosynthesis–respiration in the mats. Altogether, this study presents new insights into the ecology of ancient phosphatic stromatolites and warrants further exploration into the role of oxygen-producing biotas in the formation of Paleoproterozoic shallow-basin phosphorites.Sandron, S., Davies, N.W., Wilson, R., Cardona, A.R., Haddad, P.R., Nesterenko, P.N., Paull, B., 2018. Fractionation of dissolved organic matter on coupled reversed-phase monolithic columns and characterisation using reversed-phase liquid chromatography-high resolution mass spectrometry. Chromatographia 81, 203-213. Onyx monolithic C18 columns (100 x 3 mm) were connected in series to obtain a high-capacity reversed-phase HPLC column providing 110,000 theoretical plates. The column was used to fractionate a complex mixture of semi-polar and apolar components within marine dissolved organic matter (DOM), isolated using solid-phase extraction (SPE) on poly(styrene–divinylbenzene) cartridges, and Suwannee River natural organic matter, isolated by reverse osmosis. In each case, 15 isolated fractions were further separated using a second-dimension reversed-phase HPLC coupled with high-resolution mass spectrometry. Successful fractionation of the major compositional materials within DOM (i.e. carboxylic-rich alicyclic molecules, CRAM) in order of decreasing polarity was confirmed. Upon formulae assignment, homologous series of compounds were fractionated according to decreasing O/C ratio and increasing H/C ratio. Different compounds with the same exact masses were separated across six fractions, highlighting the immensely complex nature of the material, with the presence of potentially hundreds of molecules for each molecular formula. Both samples showed clear compositional differences not only related to source (seawater or freshwater), but also to the extraction method applied (SPE or reverse osmosis).Santos, M.S., Franco, L.F.M., Castier, M., Economou, I.G., 2018. Molecular dynamics simulation of n-alkanes and CO2 confined by calcite nanopores. Energy & Fuels 32, 1934-1941. advances on the recovery of oil and gas from shale and tight reservoirs have put in focus the need for a better understanding of the behavior of fluids under confinement. Confinement effects must be considered when the pore size is on the order of a few nanometers. Pores of such a small scale are abundant in shale and tight reservoirs, justifying the unique properties and characteristics observed in fluids of such reservoirs. Furthermore, the development of techniques for geological carbon reinjection and storage makes the understanding essential of how CO2 interacts with the reservoir medium and its fluids. In this work, we use molecular dynamics simulations to predict the behavior of n-alkanes and CO2 mixtures confined by calcite slit nanopores. We observe that CO2 displaces the hydrocarbons adsorbed on the calcite surface, while the number of calcium sites controls the amount of CO2 adsorbed on the pore surface. This suggests that the reinjection of CO2 in tight oil and gas reservoirs may help enhance hydrocarbon recovery. Furthermore, the temperature, pore size, CO2 fraction, and n-alkane length are shown to be critical factors for the selective adsorption of CO2 over n-alkanes.Sargeant, S.L., Murrell, J.C., Nightingale, P.D., Dixon, J.L., 2018. Basin-scale variability of microbial methanol uptake in the Atlantic Ocean. Biogeosciences Discussions 2018, 1-28. is a climate active gas and the most abundant oxygenated volatile organic compound (OVOC) in the atmosphere and seawater. Marine methylotrophs are aerobic bacteria that utilise methanol from seawater as a source of carbon (assimilation) and/or energy (dissimilation). A few spatially limited studies have previously reported methanol oxidation rates in seawater; however the basin-wide ubiquity of marine microbial methanol utilisation remains unknown. This study uniquely combines seawater 14C labelled methanol tracer studies with 16S rRNA pyrosequencing to investigate variability in microbial methanol dissimilation and known methanol utilising bacteria throughout a meridional transect of the Atlantic Ocean between 47°?N to 39°?S. Microbial methanol dissimilation varied between 0.05–1.68?nmol?l?1?h?1 in the top 200?m of the Atlantic Ocean and showed significant variability between biogeochemical provinces. The highest rates of methanol dissimilation were found in the northern subtropical gyre (average 0.99?±?0.41?nmol?l?1?h?1), which were up to eight times greater than other Atlantic regions. Microbial methanol dissimilation rates displayed a significant inverse correlation with heterotrophic bacterial production (determined using 3H-leucine). Despite significant depth stratification of bacterial communities, methanol dissimilation rates showed much greater variability between oceanic provinces compared to depth. There were no significant differences in rates between samples collected under light and dark environmental conditions. The variability in the numbers of SAR11 (16S rRNA gene sequences) were estimated to explain approximately 50?% of the changes in microbial methanol dissimilation rates. We estimate that SAR11 cells in the Atlantic Ocean account for between 0.3–59?% of the rates of methanol dissimilation in Atlantic waters, compared to <?0.01–2.3?% for temperate coastal waters. These results make a substantial contribution to our current knowledge and understanding of the utilisation of methanol by marine microbial communities, but highlight the lack of understanding of in situ methanol production mechanisms.Sato, A., Kitazawa, Y., Ochi, T., Shoji, M., Komatsu, Y., Kayanuma, M., Aikawa, Y., Umemura, M., Shigeta, Y., 2018. First-principles study of the formation of glycine-producing radicals from common interstellar species. Molecular Astrophysics 10, 11-19., the simplest amino acid, has been intensively searched for in molecular clouds, and the comprehensive clarification of the formation path of interstellar glycine is now imperative. Among all the possible glycine formation pathways, we focused on the radical pathways revealed by Garrod (2013). In the present study, we have precisely investigated all the chemical reaction steps related to the glycine formation processes based on state-of-the-art density functional theory (DFT) calculations. We found that two reaction pathways require small activation barriers (ΔE? ≤ 7.75 kJmol–1), which demonstrates the possibility of glycine formation even at low temperatures in interstellar space if the radical species are generated. The origin of carbon and nitrogen in the glycine backbone and their combination patterns are further discussed in relation to the formation mechanisms. According to the clarification of the atomic correspondence between glycine and its potential parental molecules, it is shown that the nitrogen and two carbons in the glycine can originate in three common interstellar molecules, methanol, hydrogen cyanide, and ammonia, and that the source molecules of glycine can be described by any of their combinations. The glycine formation processes can be categorized into six patterns. Finally, we discussed two other glycine formation pathways expected from the present DFT calculation results.Saunders, P.J., McCoy, D., Goldstein, R., Saunders, A.T., Munroe, A., 2018. A review of the public health impacts of unconventional natural gas development. Environmental Geochemistry and Health 40, 1-57. public health impact of hydraulic fracturing remains a high profile and controversial issue. While there has been a recent surge of published papers, it remains an under-researched area despite being possibly the most substantive change in energy production since the advent of the fossil fuel economy. We review the evidence of effects in five public health domains with a particular focus on the UK: exposure, health, socio-economic, climate change and seismicity. While the latter would seem not to be of significance for the UK, we conclude that serious gaps in our understanding of the other potential impacts persist together with some concerning signals in the literature and legitimate uncertainties derived from first principles. There is a fundamental requirement for high-quality epidemiological research incorporating real exposure measures, improved understanding of methane leakage throughout the process, and a rigorous analysis of the UK social and economic impacts. In the absence of such intelligence, we consider it prudent to incentivise further research and delay any proposed developments in the UK. Recognising the political realities of the planning and permitting process, we make a series of recommendations to protect public health in the event of hydraulic fracturing being approved in the UK.Scheibye, K., Christensen, J.H., Johnsen, A.R., 2017. Biodegradation of crude oil in Arctic subsurface water from the Disko Bay (Greenland) is limited. Environmental Pollution 223, 73-80. degradation is the main process for oil degradation in a subsurface oil plume. There is, however, little information on the biodegradation potential of Arctic, marine subsurface environments. We therefore investigated oil biodegradation in microcosms at 2 °C containing Arctic subsurface seawater from the Disko Bay (Greenland) and crude oil at three concentrations of 2.5–10 mg/L. Within 71 days, the total petroleum hydrocarbon concentration decreased only by 18 ± 18% for an initial concentration of 5 mg/L. The saturated alkanes nC13-nC30 and the isoprenoids iC18-iC21 were biodegraded at all concentrations indicating a substantial potential for biodegradation of these compound classes. Polycyclic aromatic compounds (PACs) disappeared from the oil phase, but dissolution was the main process of removal. Analysis of diagnostic ratios indicated almost no PAC biodegradation except for the C1-naphthalenes. To conclude, the marine subsurface microorganisms from the Disko Bay had the potential for biodegradation of n-alkanes and isoprenoids while the metabolically complex and toxic PACs and their alkylated homologs remained almost unchanged.Scheiner, F., Holcová, K., Milovsk?, R., Kuhnert, H., 2018. Temperature and isotopic composition of seawater in the epicontinental sea (Central Paratethys) during the Middle Miocene Climate Transition based on Mg/Ca, δ18O and δ13C from foraminiferal tests. Palaeogeography, Palaeoclimatology, Palaeoecology 495, 60-71. regarding seawater temperature and isotopic composition of seawater in the Central Paratethys, during the Miocene epoch, are not well known. Here we present an insight based on results from a combination of Mg/Ca, δ18O and δ13C on foraminifera from the shallow core (LOM-1) representing the time interval of ~ 14.4 to 14.36 Ma. Globigerinoides trilobus, Globigerina bulloides, Cibicidoides spp. and Melonis pompilioides were chosen for analysis due to their variable ecological preferences within the water column and on the sea floor. We assessed problems concerning diagenetic alteration of foraminiferal calcite by using a single test approach when analysing δ18O and δ13C. Paleotemperature ranges turned out to be comparable with modern subtropical regions with no cooling trend as was expected at this period following the Middle Miocene Climatic Optimum. However, we find an interesting offset between the benthic species temperature response that is likely related to the different life-strategies of those species. Based on a combination of mentioned proxies it was possible to partly reconstruct δ18Oseawater for the studied locality and compare it with Mg/Ca derived temperature to obtain a possible correlation between temperature and salinity. We also investigated differences in surface and bottom water hydrography in comparison with the Mediterranean, and distinguish their different hydrographies. In addition, it was possible to identify dissimilar origins of surface and bottom water masses based on comparison of their isotopic composition.Schirone, M., Berti, M., Visciano, P., Chiumiento, F., Migliorati, G., Tofalo, R., Suzzi, G., Di Giacinto, F., Ferri, N., 2018. Determination of lipophilic marine biotoxins in mussels harvested from the Adriatic Sea by LC-MS/MS. Frontiers in Microbiology 9, 152. doi: 10.3389/fmicb.2018.00152. marine biotoxins include okadaic acid, pectenotoxin, yessotoxin and azaspiracid groups. The consumption of contaminated molluscs can lead to acute food poisoning syndromes depending on the exposure level. Regulatory limits have been set by Regulation (European Community, 2004a) No 853/2004 and LC-MS/MS is used as the official analytical method according to Regulation (European Community, 2011) No 15/2011. In this study specimens of mussels (Mytilus galloprovincialis) were collected along the coasts of the central Adriatic Sea during the years 2015–2017 and analyzed by the European harmonized Standard Operating Procedure. The method was validated for linearity, specificity, repeatability and reproducibility and it revealed able to be used for the detection of the lipophilic marine biotoxins. Levels of okadaic acid, pectenotoxin, yessotoxin and its analogs were detected at different concentrations in 148 (37%) out of a total of 400 samples, always below the maximum limits, except for 11 (4.3%) of them that were non-compliant because they exceeded the regulatory limit. Moreover, some samples were exposed to a multi-toxin mixture with regards to okadaic acid, yessotoxin and 1-Homo yessotoxin. Following these results, the aquaculture farms from which the non-compliant samples derived were closed until the analytical data of two consecutive samplings returned favorable. Besides the potential risk of consumption of mussels contaminated by lipophilic marine biotoxins, these marine organisms can be considered as bio-indicators of the contamination status of the marine ecosystem.Schmidt, A.R., Kaulfuss, U., Bannister, J.M., Baranov, V., Beimforde, C., Bleile, N., Borkent, A., Busch, A., Conran, J.G., Engel, M.S., Harvey, M., Kennedy, E.M., Kerr, P.H., Kettunen, E., Kiecksee, A.P., Lengeling, F., Lindqvist, J.K., Maraun, M., Mildenhall, D.C., Perrichot, V., Rikkinen, J., Sadowski, E.-M., Seyfullah, L.J., Stebner, F., Szwedo, J., Ulbrich, P., Lee, D.E., 2018. Amber inclusions from New Zealand. Gondwana Research 56, 135-146. ecosystems of the long-isolated former Gondwanan landmass of New Zealand are hotspots of modern global biodiversity, based on the level of endemism and distinctiveness of the biota. However, little is known of the evolutionary history of the rarely preserved but diverse, distinctive, fragile, mainly soft-bodied organisms such as arthropods and fungi that comprise 95% of biodiversity in forest ecosystems. Our discovery of fossils preserved in Oligocene/Miocene amber of araucarian origin reveals a diverse invertebrate and fungal biota and complex ecological networks. These fossils comprise 10 orders and approximately 20 families of terrestrial arthropods and include representatives of Pseudoscorpiones, Acari, Araneae, Collembola, Hemiptera, Psocoptera, Hymenoptera, Coleoptera, Lepidoptera and Diptera, together with nematodes, mold fungi and araucarian wood. Ecologically the fossils encompass predators such as spiders with web remains, soil and bark mites, detritivores, parasites, fungivores and decomposers, fungi that grew on solidified resin flows, as well as predatory fungi. This study reports the first major amber deposit with an abundance of biological inclusions from the Southern Hemisphere and the only Cenozoic one of verified araucarian origin. These fossils expand the global record and evolutionary history of many arthropod and fungal groups, providing insights into mid-Cenozoic araucarian forest ecosystems and resolving controversial issues around the antecedents of the modern New Zealand terrestrial biota.Sea, M.A., Garcias-Bonet, N., Saderne, V., Duarte, C.M., 2018. Carbon dioxide and methane emissions from Red Sea mangrove sediments. Biogeosciences Discussions 2018, 1-38. forests are highly productive tropical and subtropical coastal systems that provide a variety of ecosystem services, including the sequestration of carbon. While mangroves are reported to be the most intense carbon sinks among all forests, their sediments can also support large emissions of greenhouse gases (GHG), such as carbon dioxide (CO2) and methane (CH4), to the atmosphere. However, data derived from arid mangrove systems like the Red Sea are lacking. Here, we report emission rates of CO2 and CH4 from mangrove sediments along the Saudi Arabian coast of the Red Sea, and assess the relative role of these two gases in supporting total GHG emissions. Diel CO2 and CH4 emission rates in Red Sea mangrove sediments ranged from ?3452 to 7500??mol?CO2?m?2?d?1 and from 0.9 to 13.3??mol?CH4?m?2?d?1, respectively. The rates reported here fall within previously reported ranges for both CO2 and CH4, but maximum CO2 and CH4 flux rates in the Red Sea are 10 to 100-fold below those previously reported for mangroves elsewhere. Based on the isotopic composition of the CO2 and CH4 produced by mangrove sediments, we identified the origin of the organic matter that supports GHG emissions. In most of the mangrove stands, GHG emissions were supported by organic matter from mixed sources while only in one mangrove stand the GHG emissions were supported by organic matter derived from mangrove tissues. Moreover, the organic matter derived from mangrove tissues reduced CO2 fluxes and enhanced CH4 production, pointing out the importance of the origin of the organic matter in GHG emissions. Methane was the main source of CO2-equivalents, despite the comparatively low emission rates, in most of the sampled mangroves, and therefore deserves careful monitoring in this region. Despite the mean net emission of CO2 and CH4 by Red Sea mangroves reported here, these forests become net organic carbon sinks when taking into account the existing carbon burial rates for the Red Sea mangroves. By further resolving GHG fluxes in arid mangroves, we will better ascertain the role of these forests in global carbon budgets.Seeley, J.V., Schimmel, N.E., Seeley, S.K., 2018. The multi-mode modulator: A versatile fluidic device for two-dimensional gas chromatography. Journal of Chromatography A 1536, 6-15. fluidic device called the multi-mode modulator (MMM) has been developed for use as a comprehensive two-dimensional gas chromatography (GC x GC) modulator. The MMM can be employed in a wide range of capacities including as a traditional heart-cutting device, a low duty cycle GC x GC modulator, and a full transfer GC x GC modulator. The MMM is capable of producing narrow component pulses (widths <50 ms) while operating at flows compatible with high resolution chromatography. The sample path of modulated components is confined to the interior of a joining capillary. The joining capillary dimensions and the position of the columns within the joining capillary can be optimized for the selected modulation mode. Furthermore, the joining capillary can be replaced easily and inexpensively if it becomes fouled due to sample matrix components or column bleed. The principles of operation of the MMM are described and its efficacy is demonstrated as a heart-cutting device and as a GC x GC modulator.Seligmann, H., Raoult, D., 2018. Stem-loop RNA hairpins in giant viruses: Invading rRNA-like repeats and a template free RNA. Frontiers in Microbiology 9, 101. doi: 10.3389/fmicb.2018.00101. examine the hypothesis that de novo template-free RNAs still form spontaneously, as they did at the origins of life, invade modern genomes, contribute new genetic material. Previously, analyses of RNA secondary structures suggested that some RNAs resembling ancestral (t)RNAs formed recently de novo, other parasitic sequences cluster with rRNAs. Here positive control analyses of additional RNA secondary structures confirm ancestral and de novo statuses of RNA grouped according to secondary structure. Viroids with branched stems resemble de novo RNAs, rod-shaped viroids resemble rRNA secondary structures, independently of GC contents. 5′ UTR leading regions of West Nile and Dengue flavivirid viruses resemble de novo and rRNA structures, respectively. An RNA homologous with Megavirus, Dengue and West Nile genomes, copperhead snake microsatellites and levant cotton repeats, not templated by Mimivirus' genome, persists throughout Mimivirus' infection. Its secondary structure clusters with candidate de novo RNAs. The saltatory phyletic distribution and secondary structure of Mimivirus' peculiar RNA suggest occasional template-free polymerization of this sequence, rather than noncanonical transcriptions (swinger polymerization, posttranscriptional editing).Sergeeva, Y.E., Mostova, E.B., Gorin, K.V., Komova, A.V., Konova, I.A., Pojidaev, V.M., Gotovtsev, P.M., Vasilov, R.G., Sineoky, S.P., 2017. Calculation of biodiesel fuel characteristics based on the fatty acid composition of the lipids of some biotechnologically important microorganisms. Applied Biochemistry and Microbiology 53, 807-813. interdependences between the structure of fatty acid and biofuel characteristics obtained from these fatty acids were briefly reviewed. The fatty acid compositions of the lipids of yeasts and phototrophic microorganisms were analyzed. The main parameters of the biodiesel (iodine value, cetane number, and kinematic viscosity) that can be made from the lipids of these microorganisms were calculated based on the data and compared to the current standards. The lipids of the yeast Rhodosporidium toruloides VKPM Y-3349 were shown to be the most suitable for biofuel production due to the composition and content of fatty acid. The possibilities of a decrease in the prime cost of microbial lipids (along with plant oils) that would make them competitive raw material for biofuel production were considered.Shaffer, G., Lambert, F., 2018. In and out of glacial extremes by way of dust?climate feedbacks. Proceedings of the National Academy of Sciences 115, 2026-2031.: In observational data, we find striking and globally coherent increases of atmospheric dust concentrations and deposition during the coldest phases of glacial?interglacial climate cycles. As shown by our simulations with a climate?carbon cycle model, such a relationship between dust and climate implies that dust-induced cooling is responsible for the final step from intermediate to extreme glacial cooling and drawdown of atmospheric CO2 concentrations. These results also increase our overall understanding of glacial?interglacial cycles by putting further constraints on the timing and strength of other processes involved in these cycles, like changes in sea ice and ice sheet extents or changes in ocean circulation and deep water formation.Abstract: Mineral dust aerosols cool Earth directly by scattering incoming solar radiation and indirectly by affecting clouds and biogeochemical cycles. Recent Earth history has featured quasi-100,000-y, glacial?interglacial climate cycles with lower/higher temperatures and greenhouse gas concentrations during glacials/interglacials. Global average, glacial maxima dust levels were more than 3 times higher than during interglacials, thereby contributing to glacial cooling. However, the timing, strength, and overall role of dust?climate feedbacks over these cycles remain unclear. Here we use dust deposition data and temperature reconstructions from ice sheet, ocean sediment, and land archives to construct dust?climate relationships. Although absolute dust deposition rates vary greatly among these archives, they all exhibit striking, nonlinear increases toward coldest glacial conditions. From these relationships and reconstructed temperature time series, we diagnose glacial?interglacial time series of dust radiative forcing and iron fertilization of ocean biota, and use these time series to force Earth system model simulations. The results of these simulations show that dust?climate feedbacks, perhaps set off by orbital forcing, push the system in and out of extreme cold conditions such as glacial maxima. Without these dust effects, glacial temperature and atmospheric CO2 concentrations would have been much more stable at higher, intermediate glacial levels. The structure of residual anomalies over the glacial?interglacial climate cycles after subtraction of dust effects provides constraints for the strength and timing of other processes governing these cycles.Sharbatian, A., Abedini, A., Qi, Z., Sinton, D., 2018. Full characterization of CO2–oil properties on-chip: Solubility, diffusivity, extraction pressure, miscibility, and contact angle. Analytical Chemistry 90, 2461-2467. capture, storage, and utilization technologies target a reduction in net CO2 emissions to mitigate greenhouse gas effects. The largest such projects worldwide involve storing CO2 through enhanced oil recovery—a technologically and economically feasible approach that combines both storage and oil recovery. Successful implementation relies on detailed measurements of CO2–oil properties at relevant reservoir conditions (P = 2.0–13.0 MPa and T = 23 and 50 °C). In this paper, we demonstrate a microfluidic method to quantify the comprehensive suite of mutual properties of a CO2 and crude oil mixture including solubility, diffusivity, extraction pressure, minimum miscibility pressure (MMP), and contact angle. The time-lapse oil swelling/extraction in response to CO2 exposure under stepwise increasing pressure was quantified via fluorescence microscopy, using the inherent fluorescence property of the oil. The CO2 solubilities and diffusion coefficients were determined from the swelling process with measurements in strong agreement with previous results. The CO2–oil MMP was determined from the subsequent oil extraction process with measurements within 5% of previous values. In addition, the oil–CO2–silicon contact angle was measured throughout the process, with contact angle increasing with pressure. In contrast with conventional methods, which require days and ～500 mL of fluid sample, the approach here provides a comprehensive suite of measurements, 100-fold faster with less than 1 μL of sample, and an opportunity to better inform large-scale CO2 projects.Sharif, K.M., Kulsing, C., Junior, A.I.d.S., Marriott, P.J., 2018. Second dimension column ensemble pressure tuning in comprehensive two-dimensional gas chromatography. Journal of Chromatography A 1536, 39-49. pressure tunable (PT) coupled column ensemble has been implemented for the second dimension (2D) separation in comprehensive two dimensional gas chromatography (GC×PTGC). This process requires two columns to be connected by a pressure junction, as a replacement for a single narrow bore, short column in 2D. Various 2D1 and 2D2 columns may be selected to provide complementary selectivity (polarity) compared to the 1D column. The tunable residence time arising from differential pressure drop in each 2D column results in a tunable fractional contribution of each column in the 2D separation. A sample mixture comprising different chemical classes, including alkanes and alcohols, is used to identify the feasibility and extent of selectivity tuning possible in GC×PTGC. The column length is also varied due to the imposed challenge of wraparound in the PT coupled column system as pressures are adjusted in the 2D separation. Different experimental parameters, stationary phase materials and column lengths have been applied to investigate and understand the separation behaviour of the 2D PT coupled column GC×GC system. Results are discussed considering analyte retention time, peak width, linear velocity and the contribution of each 2D column. A specific and unexpected example of GC×GC separation was demonstrated where the peak positions of polar and apolar compounds could almost swap their 2D retention position by application of PT. Kerosene was analysed as an example of complex sample analysis by GC×PTGC system. This process is shown to be a practical approach for altering different stationary phase selectivities in a single 2D arrangement in GC×GC.Shelford, E.J., Suttle, C.A., 2018. Virus-mediated transfer of nitrogen from heterotrophic bacteria to phytoplankton. Biogeosciences 15, 809-819. infection of bacteria by viruses releases nutrients during cell lysis and stimulates the growth of primary producers, but the path by which these nutrients flow from lysates to primary producers has not been traced. This study examines the remineralisation of nitrogen (N) from Vibrio lysates by heterotrophic bacterioplankton and its transfer to primary producers. In laboratory trials, Vibrio sp. strain PWH3a was infected with a lytic virus (PWH3a-P1) and the resulting 36.0??mol?L?1 of dissolved organic N (DON) in the lysate was added to cultures containing cyanobacteria (Synechococcus sp. strain DC2) and a natural bacterial assemblage. Based on the increase in cyanobacteria, 74?% (26.5??mol?L?1?N) of the DON in the lysate was remineralised and taken up. Lysate from Vibrio sp. strain PWH3a labeled with 15NH4+ was also added to seawater containing natural microbial communities, and in four field experiments, stable isotope analysis indicated that the uptake of 15N was 0.09 to 0.70??mol?N??g?1 of chlorophyll a. The results from these experiments demonstrate that DON from lysate can be efficiently remineralised and transferred to phytoplankton, and they provide further evidence that the viral shunt is an important link in nitrogen recycling in aquatic systems.Shen, W., Pang, X., Chen, J., Zhang, K., Chen, Z., Gao, Z., Luo, G., He, L., 2018. Ordovician hydrocarbon migration along the Tazhong No. 10 fault belt in the Tazhong Uplift, Tarim Basin, northwest China. Energy & Fuels 32, 1474-1490. Ordovician hydrocarbon migration and accumulation of the Tazhong Uplift in the Tarim Basin, northwest China, is investigated from the perspective of geological and geochemical analysis. Geochemical parameters successfully analyzed include the oil and gas properties, 17α-22,29,30-trisnorhopane/(17α-22,29,30-trisnorhopane + 18α-22,29,30-trisnorhopane) ratios, and the carbon isotope ratios of gas. Results show anomaly parameter values are observed in the no. 10 fault belt (10FB) and the no.1 fault belt (1FB). As the distance from the 10FB and 1FB increases, the parameter value anomalies weak gradually until then become disappeared in the north platform belt (NPB). This saddle-like distribution of parameters indicates the hydrocarbon is introduced into the Ordovician through 10FB and 1FB from the northern Manjiaer Depression and the uplift itself. This new conclusion is different from the conventional view to a large extent, which indicates that Ordovician hydrocarbon mainly derive from the Manjiaer Depression, and the no.1 fault is the only NW-trending oil source fault. The viewpoint of 10FB as an additional hydrocarbon charge place is further supported by the evidence from the hydrocarbon charge intensity, structural framework, source rock distribution, and significant improvement of the reservoir physical property (7–8 times that at the 10FB). Based on this hydrocarbon charge and migration process and patter, the main target for further exploration activities in the Ordovician of the Tazhong Uplift should be the SPB (south platform belt) and the south part of the 10FB, especially the southern part of the 10FB.Shen, X., Chang, H., Sun, D., Wang, L., Wu, F., 2018. Trace analysis of 61 natural and synthetic progestins in river water and sewage effluents by ultra-high performance liquid chromatography–tandem mass spectrometry. Water Research 133, 142-152. broad number of natural and synthetic progestins are widely used in human and veterinary therapies. Although progestins exhibit adverse effects in aquatic organisms, information about environmental occurrence and fate have been limited to several compounds, hampering the accuracy of risk assessments of the compounds. In this study, a selective and sensitive analytical method was established to simultaneously determine 19 natural and 42 synthetic progestins in environmental waters, and the synthetic progestins included 19-nortestosterone, 17α-hydroxyprogesterone and progesterone derivatives. All of the target compounds were effectively separated using an HSS T3 column, and the recoveries for effluent and river samples were 80–115% and 75–105%, respectively. The detection limits for the 61 analytes were in the range of 0.05–0.60?ng/L and 0.03–0.40?ng/L for the effluent and river samples, respectively. The developed method is applied to analyze the target progestogens in sewage effluent and river water samples from Beijing. The detected concentrations of natural progesterone metabolites (3α-hydroxy-5β-tetrahydroprogesterone) were up to 63 times higher than those of the parent compound. Of the three groups of synthetic progestins, the progesterone derivatives were detected for the first time and had the highest concentrations followed by the 19-nortestosterone and 17α-hydroxyprogesterone derivatives. In contrast to previous studies, the predominant derivative compounds of 19-nortestosterone were found to be 19-nortestosterone, gestodene and mifepristone, and those of 17α-hydroxyprogesterone were 6-epi-medroxy progesterone 17-acetate and melengestrol acetate. The toxicities and environmental risk of these emerging progestins deserves more attention in the future.Shen, Y., Benner, R., 2018. Mixing it up in the ocean carbon cycle and the removal of refractory dissolved organic carbon. Scientific Reports 8, Article 2542. large quantity of reduced carbon is sequestered in the ocean as refractory dissolved molecules that persist through several circuits of global overturning circulation. Key aspects of the cycling of refractory dissolved organic carbon (DOC) remain unknown, making it challenging to predict how this large carbon reservoir will respond to climate change. Herein we investigate mechanisms that remove refractory DOC using bioassay experiments with DOC isolated from surface, mesopelagic and deep waters of the Atlantic Ocean. The isolated DOC was refractory to degradation by native microbial communities, even at elevated concentrations. However, when the refractory DOC was introduced to a series of novel environmental conditions, including addition of a labile substrate, a microbial community from coastal waters and exposure to solar radiation, a substantial fraction (7–13%) was removed within 1.5 years. Our results suggest that while refractory molecules can persist in the ocean for millennia, removal is rapid when they encounter their fate. The observed and projected climate-induced slowdown of global overturning circulation could reduce the exposure of refractory molecules to disparate removal processes. Assuming a constant rate of production, the reservoir size of refractory DOC could increase as overturning circulation slows, providing a negative feedback to rising atmospheric CO2.Shi, W., Li, C., Luo, G., Huang, J., Algeo, T.J., Jin, C., Zhang, Z., Cheng, M., 2018. Sulfur isotope evidence for transient marine-shelf oxidation during the Ediacaran Shuram Excursion. Geology 46, 267-270. Ediacaran Shuram Excursion (SE) was a major negative δ13Ccarb excursion (to ?12‰) thought to reflect significant atmospheric-oceanic oxidation, although direct evidence is limited. Here, we model changes in seawater sulfate concentrations ([SO42?]sw) during the SE by using paired S-isotope data of cogenetic sedimentary pyrite and carbonate-associated sulfate from the Ediacaran Doushantuo Formation (South China), making independent calculations for inner-shelf and upper-slope sections. Our results show a significant increase of [SO42?]sw toward the peak of the SE and a large proximal-to-distal gradient across the Yangtze Platform. Our findings provide direct evidence for transient oxidation of marine-shelf water masses during the SE, providing insights into Ediacaran oceanic oxygenation, the origin of the SE, and contemporaneous bioevolutionary events.Shikhov, I., Li, R., Arns, C.H., 2018. Relaxation and relaxation exchange NMR to characterise asphaltene adsorption and wettability dynamics in siliceous systems. Fuel 220, 692-705. fraction of asphaltenes in crude oils is among the major concerns in upstream and downstream petroleum engineering. At reservoir scale asphaltenes may cause compartmentalisation and at pore scale they may create barriers to flow, change wettability conditions and relative permeability; and as a result affect ultimate oil recovery. Rock core ageing in oil is a common step in laboratory core analysis. Where possible, crude oils relevant to the origin of cores are used, while the use of arbitrary oils, various hydrophobic chemicals and anti-wetting agents is not uncommon. Published ageing time and temperature vary broadly. This fact motivates us to evaluate the applicability of synthetic oils for studies requiring wettability alteration. We systematically study the precipitation kinetics of the heavy-end oil fraction and wettability alteration properties of mixtures comprised by various proportions of commercially available bitumen, aromatics and alkane components.Low-field NMR relaxation measurements have been applied to characterise wettability of rocks by introducing an NMR wettability index. The latter requires multiple reference measurements at end-point saturation states similar to a standard Amott-Harvey workflow. Furthermore, petrophysical interpretation of T2T2 relaxation data is prone to be affected by diffusional coupling effects. NMR correlation techniques have a higher prediction capacity, e.g. the T2T2-store-T2T2 (REXSY) experiment is naturally sensitive to the spatial variation of physical properties by detecting diffusion exchange between different relaxation environments. We applied a combination of relaxation and relaxation exchange techniques to study the effect of asphaltene deposition on pore-space morphology and wettability for two siliceous systems with different surface topology. The change of wettability over ageing time in different synthetic oils was tracked using T2T2 relaxation measurements, providing estimates of ageing dynamics useful in designing wettability-related experiments.Results show that the kinetics of asphaltene deposition and wettability alteration processes are strongly dependent on chemical composition of synthetic oils, asphaltene origin (light oil or bitumen) and solid phase morphology. Elements of the resulting deposition pattern and wetting state of the cores were inferred using the proposed approach, utilising low-field NMR T2T2 relaxation and T2T2-store-T2T2 relaxation exchange experiments combined with numerical simulation of relaxation responses. The knowledge of deposition pattern and dynamics obtained mainly by the mean of combination of NMR relaxation techniques contributes to the improved design of core wettability alteration steps and potentially to enhanced petrophysical application of low-field NMR technology.Shinde, V.L., Meena, R.M., Shenoy, B.D., 2018. Phylogenetic characterization of culturable bacteria and fungi associated with tarballs from Betul beach, Goa, India. Marine Pollution Bulletin 128, 593-600. are semisolid blobs of crude oil, normally formed due to weathering of crude-oil in the sea after any kind of oil spills. Microorganisms are believed to thrive on hydrocarbon-rich tarballs and possibly assist in biodegradation. The taxonomy of ecologically and economically important tarball-associated microbes, however, needs improvement as DNA-based identification and phylogenetic characterization have been scarcely incorporated into it. In this study, bacteria and fungi associated with tarballs from touristic Betul beach in Goa, India were isolated, followed by phylogenetic analyses of 16S rRNA gene and the ITS sequence-data to decipher their clustering patterns with closely-related taxa. The gene-sequence analyses identified phylogenetically diverse 20 bacterial genera belonging to the phyla Proteobacteria (14), Actinobacteria (3), Firmicutes (2) and Bacteroidetes (1), and 8 fungal genera belonging to the classes Eurotiomycetes (6), Sordariomycetes (1) and Leotiomycetes (1) associated with the Betul tarball samples. Future studies employing a polyphasic approach, including multigene sequence-data, are needed for species-level identification of culturable tarball-associated microbes. This paper also discusses potentials of tarball-associated microbes to degrade hydrocarbons.Shrestha, N., Chilkoor, G., Vemuri, B., Rathinam, N., Sani, R.K., Gadhamshetty, V., 2018. Extremophiles for microbial-electrochemistry applications: A critical review. Bioresource Technology 255, 318-330., notably archaea and bacteria, offer a good platform for treating industrial waste streams that were previously perceived as hostile to the model organisms in microbial electrochemical systems (MESs). Here we present a critical overview of the fundamental and applied biology aspects of halophiles and thermophiles in MESs. The current study suggests that extremophiles enable the MES operations under a seemingly harsh conditions imposed by the physical (pressure, radiation, and temperature) and geochemical extremes (oxygen levels, pH, and salinity). We highlight a need to identify the underpinning mechanisms that define the exceptional electrocatalytic performance of extremophiles in MESs.Si, W., Aubry, M.-P., 2018. Vital effects and ecologic adaptation of photosymbiont-bearing planktonic foraminifera during the Paleocene-Eocene Thermal Maximum, implications for paleoclimate. Paleoceanography and Paleoclimatology 33, 112-125. isotope-size data of four major planktonic foraminifera lineages from the Paleocene-Eocene Thermal Maximum (PETM, ~56 Ma) at two locations (North Atlantic New Jersey shelf and Southern Ocean) are analyzed. By comparing changes in δ13C/δ18O-size correlation prior to and during the PETM, we present evidence of significant changes in vital effects in photosymbiont-bearing planktonic foraminifera during the PETM. The δ13C-size data indicate divergent changes in δ13C vital effects in high-latitude versus mid-latitude populations, due likely to different responses in photosymbiotic activities. Combined δ18O-size data and isotopic ranking indicates that some surface dwellers experienced changes that may be interpreted as depth migrations. Extreme temperatures (>32°C) may have exerted selective pressure and drove depth migrations. Species with flexible depth distribution were capable of adapting to rapid warming by vertical migration in the upper ocean, while populations restricted to near-surface ocean may have undergone temporal and/or regional collapse during the peak warming. From a paleo-proxy perspective, these biologic responses have the potential to obscure paleoceanographic signatures both regionally and globally.Singer, P.M., Chen, Z., Alemany, L.B., Hirasaki, G.J., Zhu, K., Xie, Z.H., Vo, T.D., 2018. Interpretation of NMR relaxation in bitumen and organic shale using polymer–heptane mixes. Energy & Fuels 32, 1534-1549. of the much debated mysteries in 1H NMR relaxation measurements of bitumen and heavy crude oils is the departure from expected theoretical trends at high viscosities, where traditional theories of 1H–1H dipole–dipole interactions predict an increase in T1 with increasing viscosity. However, previous experiments on bitumen and heavy crude oils clearly show that T1LM (i.e., log-mean of the T1 distribution) becomes independent of viscosity at high viscosities; in other words, T1LM versus viscosity approaches a plateau. We report 1H NMR data at ambient conditions on a set of pure polymers and polymer–heptane mixes spanning a wide range of viscosities (η = 0.39 cP ? 334?000 cP) and NMR frequencies (ω0/2π = f0 = 2.3 MHz ? 400 MHz) and find that at high viscosities (i.e., in the slow-motion regime) T1LM plateaus to a value T1LM> ∝ ω0 independent of viscosity, similar to bitumen. More specifically, on a frequency-normalized scale, we find that T1LM> × 2.3/f0 ? 3 ms (i.e., normalized relative to 2.3 MHz), in good agreement with bitumen and previously reported polymers. Our findings suggest that in the high-viscosity limit T1LM> and T2LM> for polymers, bitumen, and heavy crude oils can be explained by 1H–1H dipole–dipole interactions without the need to invoke surface paramagnetism. In light of this, we propose a new relaxation model to account for the viscosity and frequency dependences of T1LM and T2LM, solely based on 1H–1H dipole–dipole interactions. We also determine the surface relaxation components T1S and T2S of heptane in the polymer–heptane mixes, where the polymer acts as the “surface” for heptane. We report ratios up to T1S/T2S ? 4 and dispersion T1S(ω0) for heptane in the mix, similar to previously reported data for hydrocarbons confined in organic matter such as bitumen and kerogen. These findings imply that 1H–1H dipole–dipole interactions enhanced by nanopore confinement dominate T1S and T2S relaxation in saturated organic-rich shales.Sivaram, A.K., Logeshwaran, P., Subashchandrabose, S.R., Lockington, R., Naidu, R., Megharaj, M., 2018. Comparison of plants with C3 and C4 carbon fixation pathways for remediation of polycyclic aromatic hydrocarbon contaminated soils. Scientific Reports 8, Article 2100. phytoremediation technique has been demonstrated to be a viable option for the remediation of polycyclic aromatic hydrocarbons (PAHs) contaminated sites. This study evaluated the potential applicability of plants with C3 and C4 carbon fixation pathways for the phytoremediation of recalcitrant high molecular weight (HMW) PAHs contaminated soil. A 60 and 120-day greenhouse study was conducted which showed higher degradation of HMW PAHs in soil grown with C4 plants when compared to C3 plants. Also, no PAHs were detected in the maize cobs, sunflower, wallaby, and Sudan grass seeds at the end of the experiment. The effect of plants in modifying the microbial community and dynamics in the rhizosphere was also examined by measuring soil biochemical properties such as dehydrogenase activity and water-soluble phenols. The results demonstrate a substantial difference in the microbial populations between planted and unplanted soils, which in turn facilitate the degradation of PAHs. To the best of our knowledge, this study for the first time evaluated the phytoremediation efficacy through the A. cepa cyto- and genotoxicity assay which should be considered as an integral part of all remediation experiments.Sivasankar, P., Suresh Kumar, G., 2018. Modelling the influence of interaction between injection and formation brine salinities on in-situ microbial enhanced oil recovery processes by coupling of multiple-ion exchange transport model with multiphase fluid flow and multi-species reactive transport models. Journal of Petroleum Science and Engineering 163, 435-452. between injection water (IW) and formation water (FW) salinities during microbial flooding critically influences the dynamics of in-situ Microbial Enhanced Oil Recovery (MEOR) processes. However, the lack in understanding of the influence of salinity interactions on MEOR processes had led to unreliable prediction of MEOR performance, and non-development of efficient strategies to improve the MEOR performance. Hence, analysing the influence of salinity interactions on MEOR processes would make the prediction of MEOR processes more realistic, and thereby, it could assist in development of suitable strategies to enhance the oil recovery. Thus, in the present study, a novel mathematical model has been developed by coupling the Multiple Ion (Na, Ca, Mg, Cl, SO4) Exchange (MIE) transport model with the MEOR model, and it has been solved numerically by finite volume technique. The MIE transport model simulates the resultant spatial and temporal salinity distribution within the reservoir due to the mixing of IW and FW salinities during microbial flooding. The MEOR model simulates the coupled multiphase fluid (water-oil) flow and multispecies (microbes-nutrients) reactive transport processes within the reservoir, and finally predicts the oil recovery due to microbial flooding. Subsequently, the influence of IW and FW at different salinities on MEOR processes has been investigated. The present numerical results were validated with the experimental and analytical results. The results clearly suggest that the in-situ FW salinity was completely altered to the externally injected IW salinity, and this IW salinity dictates the entire MEOR processes as against the conventionally assumed FW salinity. Further, it is revealed that lowering the IW salinity from 0.5M to 0.1M had recovered 4.5%–14% of Original Oil in Place (OOIP) higher than that of conventionally used IW (sea water) for microbial flooding. Moreover, the MEOR performance could be enhanced significantly in reservoirs with any initial FW salinity by adopting IW salinity closer to the salinity condition at which the microbial growth and biosurfactant production is maximum. Finally, the present work assists in the selection of suitable reservoir, microbes, and IW salinity for attaining maximum oil recovery by microbial flooding. Thus, the present work helps to enhance the performance of MEOR technique.Sj?vall, P., Pomerantz, A.E., Lu, X., Mullins, O.C., 2018. Time of flight-secondary ion mass spectrometry (TOF-SIMS) study of diverse asphaltenes. Fuel 220, 638-644. spectrometry has been used to elucidate a large variety of properties of asphaltenes. Here, time-of-flight secondary ion mass spectrometry (TOF-SIMS) is used to probe three diverse asphaltene types with wide ranging fractions of alkyl carbon to the sum of alkyl plus aromatic carbon (Rc), immature source rock asphaltenes (ISA with Rc?～?0.75); petroleum asphaltenes (PA with Rc?～?0.5); and coal-derived asphaltenes (CDA with Rc?～?0.25). In addition, the asphaltenes from a commercial bitumen are examined. Primary ion surface bombardment using the Bi3+ ion yields high energy density of deposition and significant molecular fragmentation with secondary ion formation. Formation of free radical cation fragments is generally suppressed especially for smaller fragments except for specific cases. Possible structures, especially cations of common aromatic compounds, are suggested for fragments with relatively large cross section of formation. Principal component analysis of the fragmentograms allows identification of key properties of the complex fragmentation patterns for the different samples. Comparisons of TOF-SIMS fragmentograms show a fundamental difference for small fragments between CDAs and all petroleum derived asphaltenes with CDAs being dominated by aromatic carbon fragments whereas all petroleum derived asphaltenes show a large fraction of fragments from alkyl carbon. However, the type of alkyl carbon fragments did not exhibit systematic trends with Rc, nor with the extent of chemical reaction or chemical processing of the materials. Consequently, it appears that having an appreciable alkane fraction is a basic property of petroleum derived asphaltenes, but the exact type of alkane carbon for differing samples of these asphaltenes is more idiosyncratic than systematic.Smirnov, M.B., Poludetkina, E.N., 2018. Characteristics of sources of oils of Romashkino field by composition of saturated and aromatic biomarkers. Geochemistry International 56, 162-170. of saturated biomarkers revealed the presence of at least two sources of oils of the Romashkino field with the monotypic conditions. All the studied oils are characterized by presence of a large number of components—anoxia testifiers in the photic layer of sedimentation basin in the fractions of aromatic compounds. These are products full or partial hydrogenation, cyclization and degradation of polyene compounds. Total content of this group of compounds is measured in these fractions for the first time. It is shown that the total content of the anoxia testifiers is high. Thus the specific characteristic of oil source rocks is defined—their formation in the conditions of existence of anoxia in the photic layer during the entire accumulation time of initial organic matter, and the thickness of the layer infected with hydrogen sulphide was significant. On the basis of composition and content of the anoxia testifiers it is shown that the hydrogenation of initial polyenes prevailed in diagenesis over the processes of cyclization. Original Russian Text ? M.B. Smirnov, E.N. Poludetkina, 2018, published in Geokhimiya, 2018, No. 2, pp. 175–184.Smith, D.F., Podgorski, D.C., Rodgers, R.P., Blakney, G.T., Hendrickson, C.L., 2018. 21 Tesla FT-ICR mass spectrometer for ultrahigh-resolution analysis of complex organic mixtures. Analytical Chemistry 90, 2041-2047. describe complex organic mixture analysis by 21 tesla (T) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Ultrahigh mass-resolving power (m/Δm50% > 2?700?000 at m/z 400) and mass accuracy (80 ppb rms) enable resolution and confident identification of tens of thousands of unique elemental compositions. We demonstrate 2.2-fold higher mass-resolving power, 2.6-fold better mass measurement accuracy, and 1.3-fold more assigned molecular formulas compared to our custom-built, state-of-the-art 9.4 T FT-ICR mass spectrometer for petroleum and dissolved organic matter (DOM) analyses. Analysis of a heavy petroleum distillate exemplifies the need for ultrahigh-performance mass spectrometry (49?040 assigned molecular formulas for 21 T versus 29?012 for 9.4 T) and extends the identification of previously unresolved Oo, SsOo, and NOo classes. Mass selective ion accumulation (20 Thompson isolation) of an asphalt volcano sample yields 462 resolved mass spectral peaks at m/z 677 and reveals previously unresolved CcHhNnOoSs mass differences at high mass (m/z > 600). Similar performance gains are realized in the analysis of dissolved organic matter, where doubly charged Oo species are resolved from singly charged SOo species, which requires a mass-resolving power greater than 1?400?000 (at m/z 600). This direct comparison reveals the continued need for higher mass-resolving power and better mass accuracy for comprehensive molecular characterization of the most complex organic mixtures.Sorai, M., Sasaki, M., Kuribayashi, T., 2018. Field reaction experiments of carbonate minerals in spring waters: Natural analogue of geologic CO2 storage. Geofluids 2018, Article 2141878. diminish the uncertainty of the mineral trapping rate during geologic CO2 storage, the growth rate of carbonate minerals was measured in CO2-containing spring waters, which can be regarded as a natural analogue of geologic CO2 storage. The authors’ approach, using nanoscale analysis of seed crystal surfaces after immersion into spring waters, enables rapid and accurate measurement of mineral reaction rates. The results show that calcite growth rates in spring waters were lower by 1–3 orders than the values given in a database of laboratory experiment results. We verified the traditional paradigm that Mg2+ controls carbonate reaction kinetics. An increase of the Mg/Ca ratio to around 5 by adding Mg2+ to spring waters markedly reduced the calcite growth rate. However, even if effects of Mg2+ and flow rate are considered, we were unable to explain satisfactorily the difference of the calcite growth rates between those of spring waters and laboratory experiments. Therefore, other factors might also be related to the slow growth rate in nature. The present results, including the fact such that neither dolomite nor magnesite was formed even at the high Mg/Ca ratio, are expected to provide an important constraint to overestimation of the mineral trapping rate.Spacapan, J.B., Palma, J.O., Galland, O., Manceda, R., Rocha, E., D'Odorico, A., Leanza, H.A., 2018. Thermal impact of igneous sill-complexes on organic-rich formations and implications for petroleum systems: A case study in the northern Neuquén Basin, Argentina. Marine and Petroleum Geology 91, 519-531. sedimentary basins in the world host voluminous igneous sill-complexes, i.e. stacking of sills that are emplaced in different levels of the sedimentary sequence. When sills are emplaced in organic-rich sedimentary formations, they can considerably affect the thermal and maturation history of the hydrocarbon source rock and can be highly relevant elements of the petroleum system. Most models of the thermal impacts of igneous sills on source rock consider one or few intrusions. However, the parameters that govern host rock maturation related to full sill-complexes remain unclear. In this contribution, we integrate borehole data and thermal 2D-modelling to quantify the temperature and maturation effects of a sill-complex in a 2D section on the sedimentary formations of the Neuquén basin, Argentina. In this basin, extensive magmatic activity took place during Oligocene-Miocene and upper Miocene age. There are numerous magmatic intrusions, dominantly sills, emplaced in organic-rich shale formations in the study area. Our modelling results show that (1) the source rock maturation in the study area was dominantly triggered by the sills, so that the area would be immature without the sills, (2) multiple sills have more pronounced thermal impact than a single, thick sill, (3) volumes of host rock between intrusions can have different degree of maturation depending on intrusion spacing, and (4) the temperature of the host rock at the time of sill emplacement controls to a great extent the thermal and maturation impact of the sills. Our work provides valuable insights into how the sills affected hydrocarbon generation during Oligocene-Miocene and Upper Miocene magmatic activity in the Neuquén basin. In addition, our study suggests that most of the kerogen has been transformed to hydrocarbon in areas where the sills are located.Spencer, C.J., Murphy, J.B., Kirkland, C.L., Liu, Y., Mitchell, R.N., 2018. A Palaeoproterozoic tectono-magmatic lull as a potential trigger for the supercontinent cycle. Nature Geoscience 11, 97-101. geologic record exhibits periods of active and quiescent geologic processes, including magmatism, metamorphism and mineralization. This apparent episodicity has been ascribed either to bias in the geologic record or fundamental changes in geodynamic processes. An appraisal of the global geologic record from about 2.3 to 2.2 billion years ago demonstrates a Palaeoproterozoic tectono-magmatic lull. During this lull, global-scale continental magmatism (plume and arc magmatism) and orogenic activity decreased. There was also a lack of passive margin sedimentation and relative plate motions were subdued. A global compilation of mafic igneous rocks demonstrates that this episode of magmatic quiescence was terminated about 2.2 billion years ago by a flare-up of juvenile magmatism. This post-lull magmatic flare-up is distinct from earlier such events, in that the material extracted from the mantle during the flare-up yielded significant amounts of continental material that amalgamated to form Nuna — Earth’s first hemispheric supercontinent. We posit that the juvenile magmatic flare-up was caused by the release of significant thermal energy that had accumulated over some time. This flux of mantle-derived energy could have provided a mechanism for dramatic growth of continental crust, as well as the increase in relative plate motions required to complete the transition to modern plate tectonics and the supercontinent cycle. These events may also be linked to Palaeoproterozoic atmospheric oxygenation and equilibration of the carbon cycle.Spina, A., Vecoli, M., Riboulleau, A., Clayton, G., Cirilli, S., Di Michele, A., Marcogiuseppe, A., Rettori, R., Sassi, P., Servais, T., Riquier, L., 2018. Application of Palynomorph Darkness Index (PDI) to assess the thermal maturity of palynomorphs: A case study from North Africa. International Journal of Coal Geology 188, 64-78. study focuses on the thermal maturity assessment of Silurian-Devonian sediments from the Ghadamis Basin, North Africa, comparing optical and geochemical analyses of palynomorphs. In southern Tunisia, the investigated subsurface cored section comprises the Argiles Principales Formation of Silurian age. In Libya, the succession studied covers the Awaynat Wanin III and IV formations, assigned to the Late Devonian (Frasnian-Famennian).Geochemical approaches used to reconstruct thermal alteration of sediments necessitate advanced, relatively expensive analytical techniques. In this study, the effectiveness of the less costly, relatively simple approaches of visually assessing palynomorph colour to determine thermal alteration (i.e., SCI: Spore Colour Index, TAI: Thermal Alteration Index and PDI: Palynomorph Darkness Index) was evaluated.SCI and TAI are qualitative methods, strictly related to the operator's perception, which use ten and five point scales respectively, to characterize colour in terms of illustrated specimens and/or descriptions. In contrast, PDI is obtained from the measurement of the red, green and blue (RGB) intensities of light transmitted through palynomorphs, using standard optical microscopes and digital cameras.The palynomorph-based thermal alteration estimates were compared to Rock-Eval pyrolysis data from the same samples. This calibration showed a linear relationship between these quantitative parameters and PDI. These results show that PDI is more reliable than the SCI and TAI methods.Spirina, E.V., Durdenko, E.V., Demidov, N.E., Abramov, A.A., Romanovsky, V.E., Rivkina, E.M., 2017. Halophilic-psychrotrophic bacteria of an Alaskan cryopeg—a model for astrobiology. Paleontological Journal 51, 1440-1452., lenses of hypersaline unfrozen soil or water within permafrost, are a model for astrobiology, since free water can only be present on cryogenic bodies and planets in the form of brine. In this paper the diversity of aerobic halophilic-psychrotrophic microorganisms from an Alaskan cryopeg (Barrow Cape) were studied and described for the first time. This cryopeg is characterized by a constant subzero temperature (–7°C), high salinity (total mineralization is about 120 g/L) and isolation from external influences for a geologically significant period of time. Our study has revealed a large number of microorganisms capable of growth at low temperature (4°C) in a wide range of salinities from 5 to 250 g/L of NaCl, the latter being 3 times higher than the natural salt concentration of the Alaskan cryopeg. The microorganisms identified are comprised of four major phyla: Actinobacteria (genera Brevibacterium, Citricoccus, Microbacterium), Firmicutes (genus Paenibacillus), Bacteroidetes (genus Sphingobacterium), and Proteobacteria (genus Ochrobactrum).Srivastava, D., Tomaz, S., Favez, O., Lanzafame, G.M., Golly, B., Besombes, J.-L., Alleman, L.Y., Jaffrezo, J.-L., Jacob, V., Perraudin, E., Villenave, E., Albinet, A., 2018. Speciation of organic fraction does matter for source apportionment. Part 1: A one-year campaign in Grenoble (France). Science of The Total Environment 624, 1598-1611. source apportionment was performed by positive matrix factorization (PMF) using specific primary and secondary organic molecular markers on samples collected over a one year period (2013) at an urban station in Grenoble (France). The results provided a 9-factor optimum solution, including sources rarely apportioned in the literature, such as two types of primary biogenic organic aerosols (fungal spores and plant debris), as well as specific biogenic and anthropogenic secondary organic aerosols (SOA). These sources were identified thanks to the use of key organic markers, namely, polyols, odd number higher alkanes, and several SOA markers related to the oxidation of isoprene, α-pinene, toluene and polycyclic aromatic hydrocarbons (PAHs). Primary and secondary biogenic contributions together accounted for at least 68% of the total organic carbon (OC) in the summer, while anthropogenic primary and secondary sources represented at least 71% of OC during wintertime. A very significant contribution of anthropogenic SOA was estimated in the winter during an intense PM pollution event (PM10 > 50 μg m? 3 for several days; 18% of PM10 and 42% of OC). Specific meteorological conditions with a stagnation of pollutants over 10 days and possibly Fenton-like chemistry and self-amplification cycle of SOA formation could explain such high anthropogenic SOA concentrations during this period. Finally, PMF outputs were also used to investigate the origins of humic-like substances (HuLiS), which represented 16% of OC on an annual average basis. The results indicated that HuLiS were mainly associated with biomass burning (22%), secondary inorganic (22%), mineral dust (15%) and biogenic SOA (14%) factors. This study is probably the first to state that HuLiS are significantly associated with mineral dust.Stanev, E.V., Poulain, P.-M., Grayek, S., Johnson, K.S., Claustre, H., Murray, J.W., 2018. Understanding the dynamics of the oxic-anoxic interface in the Black Sea. Geophysical Research Letters 45, 864-871. Black Sea, the largest semienclosed anoxic basin on Earth, can be considered as an excellent natural laboratory for oxic and anoxic biogeochemical processes. The suboxic zone, a thin interface between oxic and anoxic waters, still remains poorly understood because it has been undersampled. This has led to alternative concepts regarding the underlying processes that create it. Existing hypotheses suggest that the interface originates either by isopycnal intrusions that introduce oxygen or the dynamics of manganese redox cycling that are associated with the sinking of particles or chemosynthetic bacteria. Here we reexamine these concepts using high-resolution oxygen, sulfide, nitrate, and particle concentration profiles obtained with sensors deployed on profiling floats. Our results show an extremely stable structure in density space over the entire basin with the exception of areas near the Bosporus plume and in the southern areas dominated by coastal anticyclones. The absence of large-scale horizontal intrusive signatures in the open-sea supports a hypothesis prioritizing the role of biogeochemical processes.Stavitskaya, A.V., Konstantinova, M.L., Razumovskii, S.D., Safieva, R.Z., Vinokurov, V.A., 2017. Analysis of sour oil ozonation products by ultra-high resolution mass-spectrometry. Petroleum Chemistry 57, 1012-1017. products of sour crude oil have been determined at the molecular level by means of ion cyclotron resonance Fourier-transform mass spectrometry in soft ionization modes. It has been shown that a proper choice of ozonation conditions makes it possible to selectively ozonize heteroatomic nitrogen, sulfur, and oxygen compounds, such as pyrrole derivatives, sulfides, disulfides, thiophene derivatives, resins, and asphaltenes. It has been found that the hydrocarbon portion of the oil is not ozonized under the given conditions. Original Russian Text ? A.V. Stavitskaya, M.L. Konstantinova, S.D. Razumovskii, R.Z. Safieva, V.A. Vinokurov, 2017, published in Neftekhimiya, 2017, Vol. 57, No. 6, pp. 633–638.Stefani, F., Isabel, N., Morency, M.-J., Lamothe, M., Nadeau, S., Lachance, D., Li, E.H.Y., Greer, C., Yergeau, ?., Pinno, B.D., Séguin, A., 2018. The impact of reconstructed soils following oil sands exploitation on aspen and its associated belowground microbiome. Scientific Reports 8, Article 2761. objective of this study was to investigate the impact of different soil covers used to reclaim decommissioned oil sands mining sites on the genetic diversity of aspen and their associated belowground microbiota. Aspen genotyping showed that trees mostly originated from sexual reproduction on sites reclaimed with soil covers made of upland forest floor-mineral mix (FFMM) and lowland peat-mineral mix (PMM). In contrast, most individuals in mature and burned stands sampled as benchmarks for natural disturbances originated from vegetative reproduction. Nonetheless, aspen populations?in the FFMM and PMM sites were not genetically different from those in mature and burned stands. DNA metabarcoding of bacteria and fungi in root and soil samples revealed that the diversity of the belowground microbiota associated with aspen and the relative abundance of putative symbiotic taxa in PMM were significantly lower than for FFMM and naturally disturbed sites. Despite similar aspen?genetic diversity between FFMM and PMM sites, trees were not associated with the same belowground microbiota. Because the soil microbiome and more specifically the mycorrhizal communities are variable both in space and time, long-term monitoring is particularly important to better understand the ecological trajectory of these novel ecosystems.Stegen, J.C., Johnson, T., Fredrickson, J.K., Wilkins, M.J., Konopka, A.E., Nelson, W.C., Arntzen, E.V., Chrisler, W.B., Chu, R.K., Fansler, S.J., Graham, E.B., Kennedy, D.W., Resch, C.T., Tfaily, M., Zachara, J., 2018. Influences of organic carbon speciation on hyporheic corridor biogeochemistry and microbial ecology. Nature Communications 9, Article 585. hyporheic corridor (HC) encompasses the river–groundwater continuum, where the mixing of groundwater (GW) with river water (RW) in the HC can stimulate biogeochemical activity. Here we propose a novel thermodynamic mechanism underlying this phenomenon and reveal broader impacts on dissolved organic carbon (DOC) and microbial ecology. We show that thermodynamically favorable DOC accumulates in GW despite lower DOC concentration, and that RW contains thermodynamically less-favorable DOC, but at higher concentrations. This indicates that GW DOC is protected from microbial oxidation by low total energy within the DOC pool, whereas RW DOC is protected by lower thermodynamic favorability of carbon species. We propose that GW–RW mixing overcomes these protections and stimulates respiration. Mixing models coupled with geophysical and molecular analyses further reveal tipping points in spatiotemporal dynamics of DOC and indicate important hydrology–biochemistry–microbial feedbacks. Previously unrecognized thermodynamic mechanisms regulated by GW–RW mixing may therefore strongly influence biogeochemical and microbial dynamics in riverine ecosystems.Stork, A.L., Allmark, C., Curtis, A., Kendall, J.M., White, D.J., 2018. Assessing the potential to use repeated ambient noise seismic tomography to detect CO2 leaks: Application to the Aquistore storage site. International Journal of Greenhouse Gas Control 71, 20-35. Aquistore project in Saskatchewan, Canada provides carbon dioxide (CO2) storage for the world's first combined commercial power plant and carbon capture and storage (CCS) project. CO2 has been injected at a depth of 3.2?km since April 2015 and a permanent near surface geophone array provides passive seismic monitoring. The ability to identify any containment breach is a vital part of risk management and reduction for CO2 storage sites. We therefore investigate the potential to monitor seismic velocity changes following a hypothetical leak of CO2 from the reservoir using passive monitoring methods. We estimate the expected shear-wave velocity change with CO2 saturation, and using data from the geophone array we investigate whether ambient noise interferometry (ANI) and a tomographic inversion for Rayleigh wave group-velocity maps could provide a suitable CO2 leakage detection tool. To assess the repeatability of the method, we conduct, for the first time, a time-lapse ambient noise tomography survey of a CO2 storage site to cover time periods preceding and following injection start-up. Sensitivity analysis results indicate that usable surface wave data derived from the current array configuration are sensitive to depths of ～400?m and shallower. We do not expect to observe any changes due to CO2 migration at such shallow depths and the estimated seismic velocities pre- and post-injection agree to within 60?m?s?1, which is on the order of double the predicted velocity change with CO2 saturation. Therefore, due to uncertainties in travel-time picks (5–15%) and variations in the obtained velocity structure between consecutive days (up to 20%), we would be unable to resolve the expected seismic velocity change with an influx of CO2 at 400?m (～3–4%). Additionally, the noise source variability does not allow stable velocity estimates to be made in the time-frame of currently-available data. Consequently, in the event of a CO2 leak at the Aquistore site, using the standard ambient noise analysis methods applied herein, Rayleigh wave tomography could be deployed to detect velocity changes due to CO2 saturation only if (a) a wider aperture surface array was in place to allow longer period surface waves to be used, providing sensitivity at greater depths, (b) arrival times of interferometrically-synthesised surface waves could be picked with increased accuracy, and (c) there is stability of the noise source distribution between repeated surveys. However, a map of three-dimensional near surface velocities, as obtained in this study, could nevertheless be useful for near surface static corrections when using active-source seismic reflection surveys to image and monitor the reservoir. More generally, further similar studies are required to assess the applicability of ANI for leak detection at other CO2 storage sites.Stuckey, J.W., Goodwin, C., Wang, J., Kaplan, L.A., Vidal-Esquivel, P., Beebe, T.P., Sparks, D.L., 2018. Impacts of hydrous manganese oxide on the retention and lability of dissolved organic matter. Geochemical Transactions 19, Article 6. constitute a primary ecosystem control on organic C decomposition in soils, and therefore on greenhouse gas fluxes to the atmosphere. Secondary minerals, in particular, Fe and Al (oxyhydr)oxides—collectively referred to as “oxides” hereafter—are prominent protectors of organic C against microbial decomposition through sorption and complexation reactions. However, the impacts of Mn oxides on organic C retention and lability in soils are poorly understood. Here we show that hydrous Mn oxide (HMO), a poorly crystalline δ-MnO2, has a greater maximum sorption capacity for dissolved organic matter (DOM) derived from a deciduous forest composite Oi, Oe, and Oa horizon leachate (“O horizon leachate” hereafter) than does goethite under acidic (pH 5) conditions. Nonetheless, goethite has a stronger sorption capacity for DOM at low initial C:(Mn or Fe) molar ratios compared to HMO, probably due to ligand exchange with carboxylate groups as revealed by attenuated total reflectance-Fourier transform infrared spectroscopy. X-ray photoelectron spectroscopy and scanning transmission X-ray microscopy–near-edge X-ray absorption fine structure spectroscopy coupled with Mn mass balance calculations reveal that DOM sorption onto HMO induces partial Mn reductive dissolution and Mn reduction of the residual HMO. X-ray photoelectron spectroscopy further shows increasing Mn(II) concentrations are correlated with increasing oxidized C (C=O) content (r = 0.78, P < 0.0006) on the DOM–HMO complexes. We posit that DOM is the more probable reductant of HMO, as Mn(II)-induced HMO dissolution does not alter the Mn speciation of the residual HMO at pH 5. At a lower C loading (2 × 102 μg C m?2), DOM desorption—assessed by 0.1 M NaH2PO4 extraction—is lower for HMO than for goethite, whereas the extent of desorption is the same at a higher C loading (4 × 102 μg C m?2). No significant differences are observed in the impacts of HMO and goethite on the biodegradability of the DOM remaining in solution after DOM sorption reaches steady state. Overall, HMO shows a relatively strong capacity to sorb DOM and resist phosphate-induced desorption, but DOM–HMO complexes may be more vulnerable to reductive dissolution than DOM–goethite complexes.Subhash, Y., Lee, S.-S., 2018. Roseomonas deserti sp. nov., isolated from crude oil contaminated desert sand. International Journal of Systematic and Evolutionary Microbiology 68, 675-680. dark pink pigmented bacterial strains (M3T and M11) were isolated from crude oil contaminated desert sand from Kuwait. Both strains were Gram-stain-negative and small-rod to oval-shaped bacteria. Strains M3T and M11 grew at 13–42?°C (optimum, 30–35?°C) and pH 6.5–9.0 (optimum, 7.0–7.5). No additional NaCl was required for the growth of both strains. The genomic DNA G+C?content of strains M3T and M11 were 69.5 and 69.0?mol%, respectively. Both strains were closely related and the mean DNA–DNA hybridization value was 92±1?%. 16S rRNA gene sequence comparisons of both strains indicated that they belong to the genus Roseomonas . Strains M3T and M11 had a sequence similarity of 97.3 and 97.4?% with Roseomonas oryzae JC288T, respectively. Both strains had <97?% 16S rRNA gene sequence similarity with other members of the genus Roseomonas . Strain M3T showed 18±2?and 13±2?%?reassociation (based on DNA–DNA hybridization) with R. oryzae KCTC 42542T and Roseomonas cervicalis KACC 11686T, respectively. The major cellular fatty acids (>5?%) were identified as C18?:?1ω6c/C18?:?1ω7c, C16?:?1ω6c/C16?:?1ω7c and C16?:?0 in both strains. Both strains showed diphosphatidylglycerol, phosphatidylglycerol, phosphatidyl-ethanolamine, phosphatidylcholine and unidentified glycolipid as major polar lipids. Based on distinct phenotypic, genotypic and phylogenetic differences from the previously described taxa, we propose the classification of strains M3T and M11 as representative of a novel species in the genus Roseomonas , for which the name Roseomonas deserti sp. nov. is suggested. The type strain is M3T (=KEMB 2255-459T=JCM 31275T). The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain M3T is LT837512.Sun, D., Tang, J., He, Y., Liao, W., Sun, Y., 2018. Sources, distributions, and burial efficiency of terrigenous organic matter in surface sediments from the Yellow River mouth, northeast China. Organic Geochemistry 118, 89-102. geochemical studies of surface sediments from Laizhou Bay, the Yellow River mouth, northeast China, were conducted to reveal the sources, distributions, and burial efficiency of terrigenous OC exported by the Yellow River. Bulk OC contents and δ13Corg values from 204 samples show that terrigenous OC mainly accumulates in two muddy patches, basically controlled by hydrodynamic conditions. Distributions and stable carbon isotopic compositions of individual n-alkanes from 45 samples suggest that short-chain n-alkanes, with even carbon-number predominance, are most likely microbial products from degradation of riverine fossil OC, whereas long-chain odd-numbered n-alkanes (n-C27, n-C29 and n-C31) and long-chain even-numbered n-alkanes (n-C26, n-C28 and n-C30) are representative of riverine soil OC and fossil OC, respectively. Integrated with previous reports of ～100% burial efficiency of soil OC in the Yellow River mouth, concentration ratios of n-C27+29+31 to OC and n-C26+28+30 to n-C27+29+31 from the riverine particles to surface sediments in Laizhou Bay were constructed to indicate relative terrigenous OC contributions and fossil OC burial efficiency, respectively. The results suggest that the terrigenous OC contribution ranges from 14% to 57% in Laizhou Bay, with the highest values in the two muddy patches as well as in areas near the river mouth. The fossil OC burial efficiency ranges from 36% to 76%, with an TOC-weighted mean value of 42%. The 58% fossil OC lost during the transport and burial processes in the Yellow River mouth may provide a significant CO2 source.Sun, J., Zhu, X., Li, Z., 2018. Confirmation and global significance of a large-scale early Neoproterozoic banded iron formation on Hainan Island, China. Precambrian Research 307, 82-92. Shilu iron ore deposit on Hainan Island, China, contains >?460?Mt of Fe ore reserves and formed during the early Neoproterozoic (1.0–0.8?Ga). However, the genesis of the deposit and whether the deposit actually represents a banded iron formation remain controversial. Here, we present new petrographic, whole-rock geochemical, and Fe isotopic data for Fe ores from the Shilu deposit. These samples have variable but strongly positive Fe isotopic compositions (?0.29‰ to 1.62‰ for δ56FeIRMM-014), contain alternating Si-rich and Fe-rich bands at millimetre to centimetre scales that are identical to those typically found in banded iron formations, and contain widespread fine-grained jasper. They have whole-rock compositions that contain elevated concentrations of Fe and Si, and have post-Archean Australian shale (PAAS)-normalised rare earth element (REE) patterns that are similar to the compositions of chemical sediments. These observations strongly suggest that the Shilu Fe ores were originally a banded iron formation.It is also likely that the Shilu iron formation of Hainan Island correlates with the Aok iron formations in Canada, as evidenced by paleogeographic reconstructions and stratigraphic correlations, indicating that these units represent an early Neoproterozoic iron-formation depositional event related to tectono-hydrothermal activity. The presence of these early Neoproterozoic iron formations that are not associated with glacial deposits indicates that global glaciation is not a requirement for the generation of Neoproterozoic iron formations. Therefore, tectono-hydrothermal activity, rather than seawater redox conditions, is the main controlling factor related to the deposition of banded iron formations.Sun, M., Sandahl, M., Turner, C., 2018. Comprehensive on-line two-dimensional liquid chromatography?×?supercritical fluid chromatography with trapping column-assisted modulation for depolymerised lignin analysis. Journal of Chromatography A 1541, 21-30. depolymerisation produces a large variety of low molecular weight phenolic compounds that can be upgraded to value-added chemicals. Detailed analysis of these complex depolymerisation mixtures is, however, hampered by the lack of resolving power of traditional analysis techniques. In this study, a novel online comprehensive two-dimensional reversed-phase liquid chromatography (RPLC)?×?supercritical fluid chromatography (SFC) method with trapping column interface was developed for the separation of phenolic compounds in depolymerised lignin samples. The trapping capacities of different trapping columns were evaluated. The influence of large volume water-containing injection on SFC performance was studied. The relation between peak capacity and first dimension flow rate and gradient was investigated. The optimized method was applied for the analysis of a depolymerised lignin sample. The RPLC?×?SFC system exhibited high degree of orthogonality. Compared with traditional loop based interface, trapping column interface can significantly shorten the analysis time and offer higher detectability, with the disadvantage of more severe undersampling in the first dimension.Sundaram, S., Thakur, I.S., 2018. Induction of calcite precipitation through heightened production of extracellular carbonic anhydrase by CO2 sequestering bacteria. Bioresource Technology 253, 368-371. thermo-alkalotolerant bacterium exhibiting heightened extracellular carbonic anhydrase (CA) activity, survived at 100?mM sodium bicarbonateand 5% gaseous CO2 was identified as Bacillus sp. by 16S rRNA sequencing. Extracellular carbonic anhydrase was purified by ammonium sulfate precipitation, gel filtration chromatography and affinity chromatography with a yield of 46.61% and specific activity of 481.66?U/mg. The size of purified carbonic anhydrase was approximately 28?kDa in SDS-PAGE gel filtration and further their role in calcium carbonate production was correlated. The purified enzyme was stable with half-life of 25.36?min at 90?°C and pH 8. KM and Vmax values of the enzyme were 1.77?mg/mL and 385.69?U/mg respectively. The production of calcite was confirmed by Scanning Electron Microscopy (SEM) analysis, FTIR, and Energy-Dispersive X-ray (EDX) analysis. Carbonic anhydrase and calcite deposition coupled with CO2 fixingbacteria is a significant approach for CO2 sequestration.Suter, E.A., Pachiadaki, M., Taylor, G.T., Astor, Y., Edgcomb, V.P., 2018. Free-living chemoautotrophic and particle-attached heterotrophic prokaryotes dominate microbial assemblages along a pelagic redox gradient. Environmental Microbiology 20, 693-712. the anoxic Cariaco Basin as a natural laboratory, particle association of bacterial and archaeal taxa was assessed by iTag sequencing and qPCR gene assays of samples spanning an oxic–anoxic–euxinic gradient. A total of 10%–12% of all bacterial and archaeal cells were found in the particle-associated (PA) fraction, operationally defined as prokaryotes captured on 2.7 ?m membranes. Both redox condition and size fraction segregated bacterial taxa. Archaeal taxa varied according to redox conditions, but were similar between size fractions. Taxa putatively associated with chemoautotrophic sulfur oxidation and nitrification dominated the free-living (FL) fraction throughout the oxycline (< 1–120 ?M O2) and upper anoxic layer. Bacteria in the oxycline's PA fraction included taxa known to be aerobic and anaerobic chemoorganotrophs. At shallow anoxic depths, PA taxa were primarily affiliated with anaerobic sulfate ( )-reducing lineages. PA fractions in the most sulfidic samples were dominated by taxa affiliated with CH4 oxidizing, fermenting and reducing lineages. Prevalence of particle-associated -reducing taxa and abundant sulfur-oxidizing taxa in both size fractions across the oxic–anoxic interface is consistent with the cryptic sulfur cycling concept. Bacterial assemblage diversity in the PA fraction always exceeded the FL fraction except in the most oxic samples, whereas Archaeal diversity was not consistently different between size fractions. Our results suggest that these particle-associated and free-living bacterial assemblages are functionally different and that the interplay between particle microhabitats and surrounding geochemical regimes is a strong selective force shaping microbial communities throughout the water column.Sutton, J.N., André, L., Cardinal, D., Conley, D.J., de Souza, G.F., Dean, J., Dodd, J., Ehlert, C., Ellwood, M.J., Frings, P.J., Grasse, P., Hendry, K., Leng, M.J., Michalopoulos, P., Panizzo, V.N., Swann, G.E.A., 2018. A review of the stable isotope bio-geochemistry of the global silicon cycle and its associated trace elements. Frontiers in Earth Science 5, 112. doi: 10.3389/feart.2017.00112. (Si) is the second most abundant element in the Earth’s crust and is an important nutrient in the ocean. The global Si cycle plays a critical role in regulating primary productivity and carbon cycling on the continents and in the oceans. Development of the analytical tools used to study the sources, sinks, and fluxes of the global Si cycle (e.g. elemental and stable isotope ratio data for Ge, Si, Zn, etc.) have recently led to major advances in our understanding of the mechanisms and processes that constrain the cycling of Si in the modern environment and in the past. Here, we provide background on the geochemical tools that are available for studying the Si cycle and highlight our current understanding of the marine, freshwater and terrestrial systems. We place emphasis on the geochemistry of dissolved and biogenic Si; presenting case studies and discussing challenges associated with the development of these environmental proxies for the global Si cycle. We also discuss how each system within the global Si cycle might change over time (i.e. sources, sinks, and processes) and the potential technical and conceptual limitations that need to be considered for future studies.Taghavi, H., Ashoori, S., Mousavi, S.H., 2018. Analyzing electrical field effect on asphaltene deposition. Petroleum Science and Technology 36, 487-493. are the heaviest and most complicated fraction in a crude oil sample and consist of condensed polynuclear aromatics, small amounts of heteroatoms (e.g., S, N, and O), and some traces of metal elements (e.g., nickel and vanadium). The main mechanisms of asphaltene deposition are precipitation (formation of asphaltene solids out of liquid phase), aggregation (formation of larger asphaltene particles), and deposition (adsorption and adhesion onto the surface). Asphaltene deposition is a major unresolved flow assurance problem in the petroleum industry, which may occur anywhere in the production system consists of reservoir, wellbore, through flowing and the separator. Asphaltene moieties in crude oil are found to carry residual surface electric charge, so by exerting an electrical field in a specific length of pipe, asphaltenes will deposit and we will have no blockage problem. Determining asphaltene electric charge is an important issue that will be done by static experiment, and then effect of electrical field on asphaltene deposition in dynamic state should be investigated. This paper discusses electric field effect on asphaltene deposition and represents a way to deposit asphaltene moieties in specific location.Taheri-Shakib, J., Shekarifard, A., Naderi, H., 2018. Analysis of the asphaltene properties of heavy crude oil under ultrasonic and microwave irradiation. Journal of Analytical and Applied Pyrolysis 129, 171-180. new technologies are quite significant in the production and development of heavy oil reservoirs. In this study, the effects of microwave (MW) and ultrasonic (US) waves on the properties of Ellam heavy crude oil of the southwest oil reservoirs of Iran have been investigated. Experimental results show that different processes occur in samples under MW radiation for 5, 10, 15 and 20 min. Under MW for 5 and 10 min we have viscosity reductions from 15.836 mPa.s to 12.234 mPa.s and 11.122 mPa.s, respectively. This is due to volume expansion with decreasing viscosifying component and high absorption capacity of heavy molecules of oil toward MW that charges the cracking process. US waves increase the viscosity of oil for all time durations because the power from US waves causes the evaporation of light compounds. Next, the effect of MW and US radiation on the asphaltene clusters using microscopic images was investigated. Results of asphaltene particle size distribution show that increasing duration of wave radiation makes the particles smaller, and the size range of asphaltene particles in the samples under MW radiation is much smaller than for the samples under US wave radiation. Moreover, in samples under MW radiation, the large particles cannot be seen. Consequently, the average particle size of asphaltene is smaller in samples under US wave radiation. But the particle size range is high, and large-sized particles in different time intervals of US radiation are observed. The results of scanning electron microscopy show that microwaves make the asphaltene conglomerate forming particles smaller and more regular in shape than the primary state, whereas ultrasonic waves completely alter the structure of the asphaltene particles, creating asphaltene clusters with a different structure. Based on the Fourier transform infrared spectra, ultrasonic exposure increases the cracking rate of the weaker bands and the condensation of aliphatic bands more than does exposure to microwaves, due to an increase in the intensity of the spectra.Taheri-Shakib, J., Shekarifard, A., Naderi, H., 2018. Experimental investigation of the asphaltene deposition in porous media: Accounting for the microwave and ultrasonic effects. Journal of Petroleum Science and Engineering 163, 453-462. study examines the effects of ultrasonic waves (US) and microwaves (MW) on the permeability in carbonate cores with different permeabilities of asphaltenes deposited therein. Using US with toluene injection restores permeability in cores with a permeability of less than 20 md, about 18.8% and 29% higher than injection of toluene without US. The US creates turbulence and cavitation, causing a change in the structure of the asphaltene conglomerations deposited in the cores. These structural changes may be due to increased levels of contact between precipitates and better penetration of the injected fluid which facilitate the process of removing them from the cores. MW, in addition to changing the structure of asphaltene clusters within the cores, reduces the amount of their polar elements, including sulfur (S), nitrogen (N), and oxygen (O). Under MW irradiation, the sulfur, nitrogen, and oxygen values were 23.5%, 18.4% and 48%, respectively. This decrease in the amount of asphaltene polar elements, which is due to their high capacity to absorb MW can reduce the negative charges in asphaltene particles. The zeta potential results also indicated that the negative charges of asphaltene particles decreased and became more positive as a result of MW radiation (from ?12.31 mV to ?7.59 mV). Fourier transform infrared spectroscopy (FTIR) spectra tests also confirmed these results. The polar bands of the asphaltene particles deposited inside the cores (OH, S-H; C=O) had a decreasing trend and escaped from the structure of the asphaltene clusters. Decreasing the polar values, especially those of the compounds with negative electrical charge (SO) actually reduces the adhesive force between asphaltene and limestone that has positive electrical charges. This phenomenon causes the removal of asphaltene particles from the porous rock media. The rate at which permeability is restored also indicates that MW radiation is much higher than the previous one (US + Toluene), especially cores with low permeability. The results of this study could be a major step towards removing asphaltene precipitates in oil reservoirs using US and MW technologies.Tang, K., Zhang, Y., Lin, D., Han, Y., Chen, C.-T.A., Wang, D., Lin, Y.-S., Sun, J., Zheng, Q., Jiao, N., 2018. Cultivation-independent and cultivation-dependent analysis of microbes in the shallow-sea hydrothermal system off Kueishantao Island, Taiwan: Unmasking heterotrophic bacterial diversity and functional capacity. Frontiers in Microbiology 9, 279. doi: 10.3389/fmicb.2018.00279. hydrothermal systems experience continuous fluctuations of physicochemical conditions due to seawater influx which generates variable habitats, affecting the phylogenetic composition and metabolic potential of microbial communities. Until recently, studies of submarine hydrothermal communities have focused primarily on chemolithoautotrophic organisms, however, there have been limited studies on heterotrophic bacteria. Here, fluorescence in situ hybridization, high throughput 16S rRNA gene amplicon sequencing, and functional metagenomes were used to assess microbial communities from the shallow-sea hydrothermal system off Kueishantao Island, Taiwan. The results showed that the shallow-sea hydrothermal system harbored not only autotrophic bacteria but abundant heterotrophic bacteria. The potential for marker genes sulfur oxidation and carbon fixation were detected in the metagenome datasets, suggesting a role for sulfur and carbon cycling in the shallow-sea hydrothermal system. Furthermore, the presence of diverse genes that encode transporters, glycoside hydrolases, and peptidase indicates the genetic potential for heterotrophic utilization of organic substrates. A total of 408 cultivable heterotrophic bacteria were isolated, in which the taxonomic families typically associated with oligotrophy, copiotrophy, and phototrophy were frequently found. The cultivation-independent and -dependent analyses performed herein show that Alphaproteobacteria and Gammaproteobacteria represent the dominant heterotrophs in the investigated shallow-sea hydrothermal system. Genomic and physiological characterization of a novel strain P5 obtained in this study, belonging to the genus Rhodovulum within Alphaproteobacteria, provides an example of heterotrophic bacteria with major functional capacity presented in the metagenome datasets. Collectively, in addition to autotrophic bacteria, the shallow-sea hydrothermal system also harbors many heterotrophic bacteria with versatile genetic potential to adapt to the unique environmental conditions.Tapia-Torres, Y., Olmedo-?lvarez, G., 2018. Life on phosphite: A metagenomics tale. Trends in Microbiology 26, 170-172., a species of phosphorus in a P3+ oxidation state, is believed to have played an important role in the primordial Earth. Figueroa et al. used metagenomics to uncover anaerobic bacterial communities from waste water waste sludge that sustain life from energy provided by phosphite.Tarhan, L.G., 2018. The early Paleozoic development of bioturbation—Evolutionary and geobiological consequences. Earth-Science Reviews 178, 177-207., the physical and chemical mixing of sediments by burrowing animals, is a critical engineering process in modern seafloor environments and exerts an important control on not only benthic ecology and sediment properties but also ocean-wide biogeochemical cycling. Well-mixed sediments have long been assumed to appear at the Precambrian–Cambrian boundary with the first occurrence of the index fossil and three-dimensional burrow Treptichnus pedum. However, field-based analyses, synthesizing ichnological, stratigraphic, sedimentological and taphonomic data collected from lower Paleozoic successions worldwide, indicate that sediment mixing in marine shelf environments remained limited until at least the late Silurian, 120?million?years after the Precambrian–Cambrian transition. In spite of early advances in complex modes of infaunalization, mixed layer development had a much more gradual trajectory and did not occur in step with the first appearance of three-dimensional burrows. The delayed appearance of modern-style intensities of sediment reworking—postdating both the Cambrian Explosion and the Great Ordovician Biodiversification Event—may be due to the late-stage radiation of mobile infaunal deposit-feeders (biological bulldozers)—the organisms which are, in modern marine settings, the most efficient bioturbators. The protracted development of the sediment mixed layer holds important implications for contemporaneous biogeochemical cycling and oxygenation of the ocean-atmosphere system. The delayed development of intensive sediment mixing may have also mediated exceptional preservation of both fossilized soft tissues and shallow-tier trace fossils, and may therefore have contributed to the anomalous preponderance of Konservat Lagerst?tten and exceptionally preserved shallow-tier trace fossils and bioglyphs characteristic of the lower Paleozoic stratigraphic record.Tarrant, A.M., Payton, S.L., Reitzel, A.M., Porter, D.T., Jenny, M.J., 2018. Ultraviolet radiation significantly enhances the molecular response to dispersant and sweet crude oil exposure in Nematostella vectensis. Marine Environmental Research 134, 96-108. organisms are subjected to combinations of anthropogenic and natural stressors, which together can reduce an organisms' ability to respond to either stress or can potentiate or synergize the cellular impacts for individual stressors. Nematostella vectensis (starlet sea anemone) is a useful model for investigating novel and evolutionarily conserved cellular and molecular responses to environmental stress. Using RNA-seq, we assessed global changes in gene expression in Nematostella in response to dispersant and/or sweet crude oil exposure alone or combined with ultraviolet radiation (UV). A total of 110 transcripts were differentially expressed by dispersant and/or crude oil exposure, primarily dominated by the down-regulation of 74 unique transcripts in the dispersant treatment. In contrast, UV exposure alone or combined with dispersant and/or oil resulted in the differential expression of 1133 transcripts, of which 436 were shared between all four treatment combinations. Most significant was the differential expression of 531 transcripts unique to one or more of the combined UV/chemical exposures. Main categories of genes affected by one or more of the treatments included enzymes involved in xenobiotic metabolism and transport, DNA repair enzymes, and general stress response genes conserved among vertebrates and invertebrates. However, the most interesting observation was the induction of several transcripts indicating de novo synthesis of mycosporine-like amino acids and other novel cellular antioxidants. Together, our data suggest that the toxicity of oil and/or dispersant and the complexity of the molecular response are significantly enhanced by UV exposure, which may co-occur for shallow water species like Nematostella.Tascon, M., Alam, M.N., Gómez-Ríos, G.A., Pawliszyn, J., 2018. Development of a microfluidic open interface with flow isolated desorption volume for the direct coupling of SPME devices to mass spectrometry. Analytical Chemistry 90, 2631-2638. that efficiently integrate the sampling and sample preparation steps with direct introduction to mass spectrometry (MS), providing simple and sensitive analytical workflows as well as capabilities for automation, can generate a great impact in a vast variety of fields, such as in clinical, environmental, and food-science applications. In this study, a novel approach that facilitates direct coupling of Bio-SPME devices to MS using a microfluidic design is presented. This technology, named microfluidic open interface (MOI), which operates under the concept of flow-isolated desorption volume, consists of an open-to-ambient desorption chamber (V ≤ 7 μL) connected to an ionization source. Subsequently, compounds of interest are transported to the ionization source by means of the self-aspiration process intrinsic of these interfaces. Thus, any ionization technology that provides a reliable and constant suction, such as electrospray ionization (ESI), atmospheric-pressure chemical ionization (APCI), or inductively coupled plasma ionization (ICP), can be hyphenated to MOI. Using this setup, the desorption chamber is used to release target compounds from the coating, while the isolation of the flow enables the ionization source to be continuously fed with solvent, all without the necessity of employment of additional valves. As a proof of concept, the design was applied to an ESI-MS/MS system for experimental validation. Furthermore, numerical simulations were undertaken to provide a detailed understanding of the fluid flow pattern inside the interface, then used to optimize the system for better efficiency. The analytical workflow of the developed Bio-SPME-MOI-MS setup consists of the direct immersion of SPME fibers into the matrix to extract/enrich analytes of interest within a short period of time, followed by a rinsing step with water to remove potentially adhering proteins, salts, and/or other interfering compounds. Next, the fiber is inserted into the MOI for desorption of compounds of interest. Finally, the volume contained in the chamber is drained and moved toward the electrospray needle for ionization and direct introduction to MS. Aiming to validate the technology, the fast determination of selected immunosuppressive drugs (e.g., tacrolimus, cyclosporine, sirolimus, and everolimus) from 100 μL of whole blood was assessed. Limits of quantitation in the subppb range were obtained for all studied compounds. Good linearity (r2 ≥ 0.99) and excellent precision, with (8%) and without (14%) internal standard correction, were attained.Tathed, P., Han, Y., Misra, S., 2018. Hydrocarbon saturation in upper Wolfcamp shale formation. Fuel 219, 375-388. saturation (SwSw) and hydrocarbon saturation (Shc=1-SwShc=1-Sw) estimates in hydrocarbon-bearing formations are generally derived from Dean-Stark core measurements, NMR log, and electromagnetic (EM) logs, such as induction log, galvanic resistivity (laterolog), or dielectric dispersion logs. In-situ estimation of hydrocarbon saturation in conventional reservoirs primarily rely on the deep-sensing or high-resolution EM logs. However, in the hydrocarbon-bearing shale formations, hydrocarbon saturation estimates obtained from EM logs tend to be unreliable. Conventional EM-log-interpretation models tend to break down for shale formations because they neglect the interfacial polarization effects and the dispersive behavior of EM properties of such geomaterials. This can be addressed by jointly processing the subsurface galvanic resistivity, induction, propagation and dielectric dispersion logs using an integrated model that accounts for the interfacial polarization mechanisms.One galvanic resistivity (laterolog) and dielectric dispersion logs, comprising 4 conductivity and 4 dielectric permittivity logs measured at four distinct frequencies, were acquired in a 520-feet depth interval of a well drilled in the upper Wolfcamp shale formation. We implement a novel log interpretation technique for the improved estimation of water saturation (SwSw), brine conductivity (Cw), textural index/cementation exponent (m), and saturation exponent (n) in the upper Wolfcamp shale. Log processing was performed with an integrated mechanistic model, which combines Complex Refractive Index (CRI) model to analyze the conductivity and permittivity logs acquired at 1?GHz, Stroud-Milton-De (SMD) model to analyze the 3 conductivity dispersion and 3 permittivity dispersion logs in the frequency range of 10?MHz to 0.3?GHz, and Waxman-Smits (WS) model to analyze the deep galvanic resistivity log (RLA5) measured by the EM laterolog tool at 1?kHz.In the upper Wolfcamp shale, estimates derived from the joint inversion were robust in the presence of pyrite, low water saturation, and low porosity as compared to estimates from the inversion of only four-frequency dielectric dispersion logs. Formation brine conductivity and saturation-exponent estimates are more reliable compared to water saturation and cementation exponent estimates. Water saturation estimates obtained using the proposed methodology are compared against those obtained using multi-mineral inversion and those derived using CRIM model. Average relative errors in fitting the 1 laterolog resistivity and 8 dielectric dispersion logs using the estimates obtained from the proposed method are 10% and 20%, respectively, and their extreme values are 55% and 60%, respectively, in the 520-ft depth interval of the upper Wolfcamp shale formation.Taubner, R.-S., Pappenreiter, P., Zwicker, J., Smrzka, D., Pruckner, C., Kolar, P., Bernacchi, S., Seifert, A.H., Krajete, A., Bach, W., Peckmann, J., Paulik, C., Firneis, M.G., Schleper, C., Rittmann, S.K.M.R., 2018. Biological methane production under putative Enceladus-like conditions. Nature Communications 9, Article 748. detection of silica-rich dust particles, as an indication for ongoing hydrothermal activity, and the presence of water and organic molecules in the plume of Enceladus, have made Saturn’s icy moon a hot spot in the search for potential extraterrestrial life. Methanogenic archaea are among the organisms that could potentially thrive under the predicted conditions on Enceladus, considering that both molecular hydrogen (H2) and methane (CH4) have been detected in the plume. Here we show that a methanogenic archaeon, Methanothermococcus okinawensis, can produce CH4 under physicochemical conditions extrapolated for Enceladus. Up to 72% carbon dioxide to CH4 conversion is reached at 50?bar in the presence of potential inhibitors. Furthermore, kinetic and thermodynamic computations of low-temperature serpentinization indicate that there may be sufficient H2 gas production to serve as a substrate for CH4 production on Enceladus. We conclude that some of the CH4 detected in the plume of Enceladus might, in principle, be produced by methanogens.Taylor, E.R., 2018. If technological intelligent extraterrestrials exist, what biological traits are de rigueur. Life Sciences in Space Research 17, 15-22. extraterrestrials exist in the depths of cosmic space, and are capable of interstellar communications, even space flight, there is no requirement that they be humanoid in form. However, certain humanoid capabilities would be advantageous for tool fashioning and critical to operating space craft as well as functioning under the disparate extreme conditions under which they may be forced to operate. They would have to be “gas breathing”. The reasonable assumption that life based upon the same elements as Earth life requiring water stems from the unique properties of water that no other similar low molecular weight nonmetal hydride offers. Only water offers the diversity of chemical properties and reactivity, including the existence of the three common physical states within a limited temperature range of service to life, avoiding the issues presented by any alternatives. They must, like us, possess a large, abstract-thinking brain, and probably possess at least all the fundamental senses that humankind possess. They would also be carbon-based life, using oxygen as the electron sink of their biochemistry for the reasons considered. They most likely are homeothermic as us, though they may not necessarily be mammalian as we are. Their biochemistry could differ some from ours, perhaps presenting contact hazards for both species as discussed.Tejero-Andrade, A., Argote-Espino, D.L., Cifuentes-Nava, G., Hernández-Quintero, E., Chávez, R.E., García-Serrano, A., 2018. ‘Illuminating’ the interior of Kukulkan's Pyramid, Chichén Itzá, Mexico, by means of a non-conventional ERT geophysical survey. Journal of Archaeological Science 90, 1-11.én Itzá, located in the north-central portion of the Yucatán Peninsula, is one of the major pre-Hispanic cities established in the southern lowlands of Mexico. The main objective of this investigation was to “unveil” the interior of the pyramid of El Castillo, also known as the Temple of Kukulkan, an emblematic structure in this archaeological site. To that end, 828 flat electrodes were deployed around each of the 9 bodies that compose the pyramid, including the base of the structure. A dataset consisting of 37,548 observations was obtained. A precise topographic control for each electrode was carried out and introduced in the inversion model. The mathematical process to compute a final 3D model was made possible by taking 9 observation levels (33,169 measurements) into account, due to computational limitations. The results showed the existence of two older pyramids within the main Mayan building and provided important information regarding our understanding of this Mayan civilization. Future archaeological studies in the older substructure could reveal information about early settlement on this site, its evolution in time and its cultural influences.Terlier, T., Lee, J., Lee, K., Lee, Y., 2018. Improvement of the correlative AFM and ToF-SIMS approach using an empirical sputter model for 3DS chemical characterization. Analytical Chemistry 90, 1701-1709. progress has spurred the development of increasingly sophisticated analytical devices. The full characterization of structures in terms of sample volume and composition is now highly complex. Here, a highly improved solution for 3D characterization of samples, based on an advanced method for 3D data correction, is proposed. Traditionally, secondary ion mass spectrometry (SIMS) provides the chemical distribution of sample surfaces. Combining successive sputtering with 2D surface projections enables a 3D volume rendering to be generated. However, surface topography can distort the volume rendering by necessitating the projection of a nonflat surface onto a planar image. Moreover, the sputtering is highly dependent on the probed material. Local variation of composition affects the sputter yield and the beam-induced roughness, which in turn alters the 3D render. To circumvent these drawbacks, the correlation of atomic force microscopy (AFM) with SIMS has been proposed in previous studies as a solution for the 3D chemical characterization. To extend the applicability of this approach, we have developed a methodology using AFM–time-of-flight (ToF)-SIMS combined with an empirical sputter model, “dynamic-model-based volume correction”, to universally correct 3D structures. First, the simulation of 3D structures highlighted the great advantages of this new approach compared with classical methods. Then, we explored the applicability of this new correction to two types of samples, a patterned metallic multilayer and a diblock copolymer film presenting surface asperities. In both cases, the dynamic-model-based volume correction produced an accurate 3D reconstruction of the sample volume and composition. The combination of AFM–SIMS with the dynamic-model-based volume correction improves the understanding of the surface characteristics. Beyond the useful 3D chemical information provided by dynamic-model-based volume correction, the approach permits us to enhance the correlation of chemical information from spectroscopic techniques with the physical properties obtained by AFM.Tian, S., Erastova, V., Lu, S., Greenwell, H.C., Underwood, T.R., Xue, H., Zeng, F., Chen, G., Wu, C., Zhao, R., 2018. Understanding model crude oil component interactions on kaolinite silicate and aluminol surfaces: Toward improved understanding of shale oil recovery. Energy & Fuels 32, 1155-1165. oil is currently of interest for unconventional resource exploration and development. Understanding the mechanism of interaction between the complex mixture of organic compounds in shale oil and minerals making up the reservoir rock–oil interface will assist recovery. In this study, molecular dynamics simulation is used to study the adsorption characteristics of a model oil mixture within nanoscale intraparticle pores of kaolinite minerals, which form pore-filling structures in shale rock. To better understand the effects of oil composition, temperature, and pressure on the adsorption properties of the model oil mixture, a range of temperatures (298, 323, 348, and 373 K) and pressures (1, 50, 100, and 200 bar) representing up to reservoir conditions were used. This study shows that adsorption and arrangement of oil molecules is dependent on the surface of kaolinite and the distance away from it. The simulations show polar compounds are likely to be adsorbed on aluminol kaolinite basal surfaces, while alkanes preferentially adsorb on silicate surfaces. In addition, the number of oil-molecule-bound layers and the total adsorption amount on the silicate surface is greater than the aluminol surface. The density of adsorbed oil is reduced with increase in temperature, while the effect of pressure is not as significant. On the basis of performed molecular simulations, we show the adsorption rate of shale oil on the surfaces of kaolinite sheets and assess the capacity to remove the model oil.Tian, Z., Vila, J., Yu, M., Bodnar, W., Aitken, M.D., 2018. Tracing the biotransformation of polycyclic aromatic hydrocarbons in contaminated soil using stable isotope-assisted metabolomics. Environmental Science & Technology Letters 5, 103-109. of organic pollutants may result in the formation of oxidation products that are more toxic than the parent contaminants. However, tracing and identifying those products, and the metabolic pathways involved in their formation, are still challenging within complex environmental samples. We applied stable isotope-assisted metabolomics (SIAM) to polycyclic aromatic hydrocarbon-contaminated soil collected from a wood treatment facility. Soil samples were separately spiked with uniformly 13C-labeled fluoranthene, pyrene, or benzo[a]anthracene at a level below that of the native contaminant and incubated for 1 or 2 weeks under aerobic biostimulated conditions. Combining high-resolution mass spectrometry and automated SIAM workflows, we propose chemical structures of metabolites and metabolic pathways in the soil. Ring-cleavage products, including previously unreported intermediates such as C11H10O6 and C15H12O5, were detected originating from fluoranthene and benzo[a]anthracene, respectively. Sulfate conjugates of dihydroxy compounds were found as major metabolites of pyrene and benzo[a]anthracene, suggesting the potential role of fungi in their biotransformation in soils. A series of unknown N-containing metabolites were identified from pyrene, but their structural elucidation requires further investigation. Our results suggest that SIAM can be successfully applied to understand the fate of organic pollutants in environmental samples, opening lines of evidence for novel mechanisms of microbial transformation within such complex matrices.Tishchenko, P.Y., Barabanshchikov, Y.A., Volkova, T.I., Marjash, A.A., Mikhailik, T.A., Pavlova, G.Y., Sagalaev, S.G., Tishchenko, P.P., Khodorenko, N.D., Shkirnikova, E.M., Shvetsova, M.G., 2018. Diagenesis of organic matter in the top layer of the sediments of the Peter the Great Bay in hypoxia locations. Geochemistry International 56, 171-181. Cruise 62nd of the R/V “Professor Gagarinsky” in September, 2014, the carbonate system of sediments and contents of nutrients and organic carbon in pore water were studied in two geochemical stations located in hypoxia areas in the Peter the Great Bay. It was established that the concentrations of silica, phosphorus, and ammonium increase by 5, 10, and 20 times, respectively, with sediment depth to 70–80 cm. The alkalinity, dissolved inorganic carbon, and the partial pressure of carbon dioxide significantly increase with depth, while рН value and organic matter (ОM) decrease. Changes in the chemical composition of pore water with sediment depth (0–80 cm) are caused by anaerobic microbial degradation of OM, concentration of which in the top sediment layer is 2–3%. The degradation products of OM in the bottom waters of bay and pore waters of bottom sediments indicate that its main sources are diatoms. During hypoxia, the oxygen demand rate by sediment surface near Furugelm Island is estimated to be 5 mmol/(m2 day). A combination of such factors as downwelling circulation, the absence of photosynthetically active radiation, and the high oxygen demand rate at the water/sediment interface provides hypoxia formation in the depressions of the Peter the Great Bay bottom topography. Original Russian Text ? P.Ya. Tishchenko, Yu.A. Barabanshchikov, T.I. Volkova, A.A. Marjash, T.A. Mikhailik, G.Yu. Pavlova, S.G. Sagalaev, P.P. Tishchenko, N.D. Khodorenko, E.M. Shkirnikova, M.G. Shvetsova, 2018, published in Geokhimiya, 2018, No. 2, pp. 185–196.Titaley, I.A., Ogba, O.M., Chibwe, L., Hoh, E., Cheong, P.H.Y., Simonich, S.L.M., 2018. Automating data analysis for two-dimensional gas chromatography/time-of-flight mass spectrometry non‐targeted analysis of comparative samples. Journal of Chromatography A 1541, 57-62. analysis of environmental samples, using comprehensive two‐dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC?×?GC/ToF-MS), poses significant data analysis challenges due to the large number of possible analytes. Non-targeted data analysis of complex mixtures is prone to human bias and is laborious, particularly for comparative environmental samples such as contaminated soil pre- and post-bioremediation. To address this research bottleneck, we developed OCTpy, a Python? script that acts as a data reduction filter to automate GC?×?GC/ToF-MS data analysis from LECO? ChromaTOF? software and facilitates selection of analytes of interest based on peak area comparison between comparative samples. We used data from polycyclic aromatic hydrocarbon (PAH) contaminated soil, pre- and post‐bioremediation, to assess the effectiveness of OCTpy in facilitating the selection of analytes that have formed or degraded following treatment. Using datasets from the soil extracts pre- and post‐bioremediation, OCTpy selected, on average, 18% of the initial suggested analytes generated by the LECO? ChromaTOF? software Statistical Compare feature. Based on this list, 63–100% of the candidate analytes identified by a highly trained individual were also selected by OCTpy. This process was accomplished in several minutes per sample, whereas manual data analysis took several hours per sample. OCTpy automates the analysis of complex mixtures of comparative samples, reduces the potential for human error during heavy data handling and decreases data analysis time by at least tenfold.Torregrosa-Crespo, J., Bergaust, L., Pire, C., Martínez-Espinosa, R.M., 2018. Denitrifying haloarchaea: sources and sinks of nitrogenous gases. FEMS Microbiology Letters 365, Article fnx270. thrive under saline and hypersaline conditions and often dominate microbial communities in saltmarshes, salted lakes/soils and some oceanic areas. Some of the predominant species show denitrifying capabilities, although it remains unclear whether they are complete or partial denitrifiers. As complete denitrifiers, they could play important roles buffering ecosystems in which nitrate and nitrite appear as contaminants. However, partial denitrifying haloarchaea could contribute to the emission of nitrogenous gasses, thus acting as drivers of climate change and ozone depletion. In this review, we summarise some recent results on denitrification in haloarchaea, discuss the environmental implications and outline possible applications in mitigation. Finally, we list questions to be addressed in the near future, facilitating increased understanding of the role of these organisms in N turnover in arid and hypersaline environments.Torres, L., Yadav, O.P., Khan, E., 2018. Risk assessment of human exposure to Ra-226 in oil produced water from the Bakken Shale. Science of The Total Environment 626, 867-874. oil production in North Dakota (ND) and other states in the United States uses large amounts of water for hydraulic fracturing to stimulate oil flow. Most of the water used returns to the surface as produced water (PW) containing different constituents. Some of these contents are total dissolved solids and radionuclides. The most predominant radionuclide in PW is radium-226 (Ra-226) of which level depends on several factors including the content of certain cations. A multivariate regression model was developed to predict Ra-226 in PW from the Bakken Shale based on the levels of barium, strontium, and calcium. The simulated Ra-226 activity concentration in PW was 535?pCi/L supporting extremely limited actual data based on three PW samples from the Bakken (527, 816, and 1210?pCi/L). The simulated activity concentration was further analyzed by studying its impact in the event of a PW spill reaching a surface water body that provides drinking water, irrigation water for crops, and recreational fishing. Using food transfer factors found in the literature, the final annual effective dose rate for an adult in ND was estimated. The global average annual effective dose rate via food and drinking water is 0.30?mSv, while the predicted dose rate in this study was 0.49?mSv indicating that there is potential risk to human health in ND due to Ra-226 in PW spills. This predicted dose rate is considered the best case scenario as it is based on the simulated Ra-226 activity concentration in PW of 535?pCi/L which is close to the low end actual activity concentration of 527?pCi/L.Tranchida, P.Q., 2018. Comprehensive two-dimensional gas chromatography: A perspective on processes of modulation. Journal of Chromatography A 1536, 2-5. first comprehensive two-dimensional gas chromatography (GC × GC) experiment was reported about 25 years ago [J. Chromatogr. Sci. 29 (1991) 227–231]; the GC × GC process was made possible by the development of a transfer device, defined as modulator. The process of modulation enables the isolation of effluent segments from the first column, and their re-injection onto the second column, in a continuous and sequential manner throughout the analysis. Over the years, many types of modulation systems have been introduced, each with specific advantages and disadvantages. Cryogenic systems are, at present, the most popular devices and represent the most effective form of modulation.The present contribution is focused on possible future scenarios, with respect to modulation, and as a consequence related to comprehensive GC, in general. The development of new forms of modulation may open the road to a more widespread use of GC × GC technologies.Tsugawa, H., 2018. Advances in computational metabolomics and databases deepen the understanding of metabolisms. Current Opinion in Biotechnology 54, 10-17. spectrometry (MS)-based metabolomics is the popular platform for metabolome analyses. Computational techniques for the processing of MS raw data, for example, feature detection, peak alignment, and the exclusion of false-positive peaks, have been established. The next stage of untargeted metabolomics would be to decipher the mass fragmentation of small molecules for the global identification of human-, animal-, plant-, and microbiota metabolomes, resulting in a deeper understanding of metabolisms. This review is an update on the latest computational metabolomics including known/expected structure databases, chemical ontology classifications, and mass spectrometry cheminformatics for the interpretation of mass fragmentations and for the elucidation of unknown metabolites. The importance of metabolome ‘databases’ and ‘repositories’ is also discussed because novel biological discoveries are often attributable to the accumulation of data, to relational databases, and to their statistics. Lastly, a practical guide for metabolite annotations is presented as the summary of this review.Tuccitto, N., Capizzi, G., Torrisi, A., Licciardello, A., 2018. Unsupervised analysis of big ToF-SIMS data sets: A statistical pattern recognition approach. Analytical Chemistry 90, 2860-2866. present a new method, fast and low demanding in terms of CPU performances, which is able to extract latent chemical information from ToF-SIMS big data sets, such as those arising from chemical imaging, by working on the unbinned raw data files. The method is able to evaluate the similarity/dissimilarity of very low intensity spectra, such as those arising from a single pixel, in terms of symmetry and asymmetry relationships of the count distribution in the Fourier transform domain. The tests performed so far on model samples show that the method supplies results that, without sacrificing mass or spatial resolution, are equivalent, at least, to those achievable by an experienced ToF-SIMS user by applying PCA techniques.V?gene, ?.J., Herbig, A., Campana, M.G., Robles García, N.M., Warinner, C., Sabin, S., Spyrou, M.A., Andrades Valtue?a, A., Huson, D., Tuross, N., Bos, K.I., Krause, J., 2018. Salmonella enterica genomes from victims of a major sixteenth-century epidemic in Mexico. Nature Ecology & Evolution 2, 520–528. populations of the Americas experienced high mortality rates during the early contact period as a result of infectious diseases, many of which were introduced by Europeans. Most of the pathogenic agents that caused these outbreaks remain unknown. Through the introduction of a new metagenomic analysis tool called MALT, applied here to search for traces of ancient pathogen DNA, we were able to identify Salmonella enterica in individuals buried in an early contact era epidemic cemetery at Teposcolula-Yucundaa, Oaxaca in southern Mexico. This cemetery is linked, based on historical and archaeological evidence, to the 1545–1550?ce epidemic that affected large parts of Mexico. Locally, this epidemic was known as ‘cocoliztli’, the pathogenic cause of which has been debated for more than a century. Here, we present genome-wide data from ten individuals for Salmonella enterica subsp. enterica serovar Paratyphi C, a bacterial cause of enteric fever. We propose that S.?Paratyphi C be considered a strong candidate for the epidemic population decline during the 1545 cocoliztli outbreak at Teposcolula-Yucundaa.van der Bilt, W.G.M., D'Andrea, W.J., Bakke, J., Balascio, N.L., Werner, J.P., Gjerde, M., Bradley, R.S., 2018. Alkenone-based reconstructions reveal four-phase Holocene temperature evolution for High Arctic Svalbard. Quaternary Science Reviews 183, 204-213. at the crossroads of major oceanic and atmospheric circulation patterns, the Arctic is a key component of Earth's climate system. Compounded by sea-ice feedbacks, even modest shifts in the region's heat budget drive large climate responses. This is highlighted by the observed amplified response of the Arctic to global warming. Assessing the imprint and signature of underlying forcing mechanisms require paleoclimate records, allowing us to expand our knowledge beyond the short instrumental period and contextualize ongoing warming. However, such datasets are scarce and sparse in the Arctic, limiting our ability to address these issues. Here, we present two quantitative Holocene-length paleotemperature records from the High Arctic Svalbard archipelago, situated in the climatically sensitive Arctic North Atlantic. Temperature estimates are based on U37K unsaturation ratios from sediment cores of two lakes. Our data reveal a dynamic Holocene temperature evolution, with reconstructed summer lake water temperatures spanning a range of ～6–8 °C, and characterized by four phases. The Early Holocene was marked by an early onset (～10.5 ka cal. BP) of insolation-driven Hypsithermal conditions, likely compounded by strengthening oceanic heat transport. This warm interval was interrupted by cooling between ～10.5–8.3 ka cal. BP that we attribute to cooling effects from the melting Northern Hemisphere ice sheets. Temperatures declined throughout the Middle Holocene, following a gradual trend that was accentuated by two cooling steps between ～7.8–7 ka cal. BP and around ～4.4–4.3 ka cal. BP. These transitions coincide with a strengthening influence of Arctic water and sea-ice in the adjacent Fram Strait. During the Late Holocene (past 4 ka), temperature change decoupled from the still-declining insolation, and fluctuated around comparatively cold mean conditions. By showing that Holocene Svalbard temperatures were governed by an alternation of forcings, this study improves our understanding of Arctic climate dynamics.Van Nuffel, S., Elie, N., Yang, E., Nouet, J., Touboul, D., Chaurand, P., Brunelle, A., 2018. Insights into the MALDI process after matrix deposition by sublimation using 3D ToF-SIMS imaging. Analytical Chemistry 90, 1907-1914. mass spectrometry (IMS) has become a powerful tool to characterize the spatial distribution of biomolecules in thin tissue sections. In the case of matrix-assisted laser desorption ionization (MALDI) IMS, homogeneous matrix deposition is critical to produce high-quality ion images, and sublimation in particular has shown to be an excellent matrix deposition method for the imaging of lipids. Matrix deposition by sublimation is, however, a completely solvent-free system, which ought to prevent the mixing of matrix and analytes thought to be necessary for successful MALDI. Using 3D time-of-flight secondary ion imaging mass spectrometry, we have studied the matrix–tissue interface in 3D with high resolution to understand the MALDI process of lipids after matrix deposition by sublimation. There is a strong indication that diffusion is the process by which lipids migrate from the tissue to the matrix layer. We show that triacylglycerols and phospholipids have a delayed migratory trend as compared to diacylglycerols and monoacylglycerols, which is dependent on time and matrix thickness. Additional experiments show that a pure lipid’s capacity to migrate into the matrix is dependent on its fluidity at room temperature. Furthermore, it is shown that cholesterol can only migrate in the presence of a (fluid) lipid and appears to fluidize lipids, which could explain its colocalization with the diacylglycerols and monoacylglycerols in the matrix.Vance, S.D., Panning, M.P., St?hler, S., Cammarano, F., Bills, B.G., Tobie, G., Kamata, S., Kedar, S., Sotin, C., Pike, W.T., Lorenz, R., Huang, H.-H., Jackson, J.M., Banerdt, B., 2018. Geophysical investigations of habitability in ice-covered ocean worlds. Journal of Geophysical Research: Planets 123, 180-205. measurements can reveal the structures and thermal states of icy ocean worlds. The interior density, temperature, sound speed, and electrical conductivity thus characterize their habitability. We explore the variability and correlation of these parameters using 1-D internal structure models. We invoke thermodynamic consistency using available thermodynamics of aqueous MgSO4, NaCl (as seawater), and NH3; pure water ice phases I, II, III, V, and VI; silicates; and any metallic core that may be present. Model results suggest, for Europa, that combinations of geophysical parameters might be used to distinguish an oxidized ocean dominated by MgSO4 from a more reduced ocean dominated by NaCl. In contrast with Jupiter's icy ocean moons, Titan and Enceladus have low-density rocky interiors, with minimal or no metallic core. The low-density rocky core of Enceladus may comprise hydrated minerals or anhydrous minerals with high porosity. Cassini gravity data for Titan indicate a high tidal potential Love number (k2>0.6), which requires a dense internal ocean (ρocean>1,200 kg m?3) and icy lithosphere thinner than 100 km. In that case, Titan may have little or no high-pressure ice, or a surprisingly deep water-rock interface more than 500 km below the surface, covered only by ice VI. Ganymede's water-rock interface is the deepest among known ocean worlds, at around 800 km. Its ocean may contain multiple phases of high-pressure ice, which will become buoyant if the ocean is sufficiently salty. Callisto's interior structure may be intermediate to those of Titan and Europa, with a water-rock interface 250 km below the surface covered by ice V but not ice VI.Veenaas, C., Haglund, P., 2018. A retention index system for comprehensive two-dimensional gas chromatography using polyethylene glycols. Journal of Chromatography A 1536, 67-74. characterization and identification of compounds in complex real-world samples is quite difficult and new concepts and workflows are highly desirable. Retention indices (RIs) are widely used in gas chromatography (GC) to support the identification of unknown compounds. Several attempts have been made to introduce a similar concept for the second dimension in comprehensive two-dimensional (2D) GC (GC?×?GC) but, an easily applicable and robust system remains elusive.In the present study, a new RI system for GC?×?GC was developed. Polyethylene glycols (PEGs) were used in combination with a simple linear regression, with n-alkanes as reference points for virtually unretained compounds and PEG homologs as reference compounds for second-dimension RIs (PEG-2I). The n-alkanes were assigned a PEG-2I of zero and the distance between consecutive PEG homologs from PEG-2 (diethylene glycol) and higher were assigned a PEG-2I value of 10. We used ethylene glycol and PEG-2 through PEG-10 as reference compounds, thereby covering a PEG-2I range from 20.0 for ethylene glycol, over 50.0 for diethylene glycol (PEG-2) to 130.0 for decaethylene glycol (PEG-10); additional PEGs can be added to cover a wider polarity range. The PEG-2I system was initially evaluated using a 30?m?×?0.25?mm non-polar (5% phenyl, 0.25?μm film thickness) first-dimension column and a 1.6?m?×?0.18?mm polar (50% phenyl, 0.18?μm film thickness) second-dimension column. This system was validated for use with non-polar first-dimension columns and a semi-polar (50% phenyl) second-dimension column, and exhibited robustness to changes in the carrier gas flow velocity, oven temperature ramping rate, and secondary oven temperature offset. An average relative standard deviation of 2.7%, equal to a 95% confidence interval of 1.27 PEG-2I units, was obtained for the PEG-2I values of 72 environmental pollutants. Additionally, the system was found to be applicable over a wide range of boiling points (in the current case, from n-heptane to n-dotriacontane (C7–C32)) and can be used with various column dimensions. Changing the second-dimension column to either a narrower 0.1?mm column or a wider 0.25?mm column, yielded similar 95%-percentiles to that of the 0.18?mm column, differing by only 3.20 and 2.80 PEG-2I units, respectively. Moreover, methods for improving the system were suggested.Vergeynst, L., Wegeberg, S., Aamand, J., Lassen, P., Gosewinkel, U., Fritt-Rasmussen, J., Gustavson, K., Mosbech, A., 2018. Biodegradation of marine oil spills in the Arctic with a Greenland perspective. Science of The Total Environment 626, 1243-1258. economic developments in the Arctic, such as shipping and oil exploitation, bring along unprecedented risks of marine oil spills. Microorganisms have played a central role in degrading and reducing the impact of the spilled oil during past oil disasters. However, in the Arctic, and in particular in its pristine areas, the self-cleaning capacity and biodegradation potential of the natural microbial communities have yet to be uncovered.This review compiles and investigates the current knowledge with respect to environmental parameters and biochemical constraints that control oil biodegradation in the Arctic. Hereby, seawaters off Greenland are considered as a case study. Key factors for biodegradation include the bioavailability of hydrocarbons, the presence of hydrocarbon-degrading bacteria and the availability of nutrients. We show how these key factors may be influenced by the physical oceanographic conditions in seawaters off Greenland and other environmental parameters including low temperature, sea ice, sunlight regime, suspended sediment plumes and phytoplankton blooms that characterize the Arctic.Based on the acquired insights, a first qualitative assessment of the biodegradation potential in seawaters off Greenland is presented. In addition to the most apparent Arctic characteristics, such as low temperature and sea ice, the impact of typical Arctic features such as the oligotrophic environment, poor microbial adaptation to hydrocarbon degradation, mixing of stratified water masses, and massive phytoplankton blooms and suspended sediment plumes merit to be topics of future investigation.Vinogradoff, V., Bernard, S., Le Guillou, C., Remusat, L., 2018. Evolution of interstellar organic compounds under asteroidal hydrothermal conditions. Icarus 305, 358-370. chondrites (CC) contain a diversity of organic compounds. No definitive evidence for a genetic relationship between these complex organic molecules and the simple organic molecules detected in the interstellar medium (ISM) has yet been reported. One of the many difficulties arises from the transformations of organic compounds during accretion and hydrothermal alteration on asteroids. Here, we report results of hydrothermal alteration experiments conducted on a common constituent of interstellar ice analogs, Hexamethylenetetramine (HMT – C6H12N4). We submitted HMT to asteroidal hydrothermal conditions at 150°C, for various durations (up to 31 days) and under alkaline pH. Organic products were characterized by gas chromatography mass spectrometry, infrared spectroscopy and synchrotron-based X-ray absorption near edge structure spectroscopy. Results show that, within a few days, HMT has evolved into (1) a very diverse suite of soluble compounds dominated by N-bearing aromatic compounds (> 150 species after 31 days), including for instance formamide, pyridine, pyrrole and their polymers (2) an aromatic and N-rich insoluble material that forms after only 7 days of experiment and then remains stable through time. The reaction pathways leading to the soluble compounds likely include HMT dissociation, formose and Maillard-type reactions, e.g. reactions of sugar derivatives with amines. The present study demonstrates that, if interstellar organic compounds such as HMT had been accreted by chondrite parent bodies, they would have undergone chemical transformations during hydrothermal alteration, potentially leading to the formation of high molecular weight insoluble organic molecules. Some of the diversity of soluble and insoluble organic compounds found in CC may thus result from asteroidal hydrothermal alteration.Voeten, R.L.C., Ventouri, I.K., Haselberg, R., Somsen, G.W., 2018. Capillary electrophoresis: Trends and recent advances. Analytical Chemistry 90, 1464-1481. the introduction of modern capillary electrophoresis (CE) by Jorgenson and Lukacs in 1981, CE has evolved into a highly mature and versatile separation technique. After a first decade of development studies and instrument commercialization, CE took its place among established analytical techniques and, for instance, became the method of choice for fast high-resolution DNA sequencing in the nineties of the last century. Although with a considerably smaller footprint than liquid and gas chromatography, CE remains to play an essential role in contemporary analytics. For example, with the strong advent of biopharmaceuticals, CE has shown to be particularly useful for routine quality control of therapeutic proteins, such as monoclonal antibodies. Current CE applications range from determination of small inorganic ions to characterization of high-molecular-weight biomolecules, and even particles and intact cells. The research field of CE remains very active, as exhibited by a steady and significant flow of scientific reports on theory, separation modes, new instrumentation, and applications of CE techniques in various areas. The present review provides a brief cross section of new developments in the broad field of CE, covering the period between September 2015 and September 2017. An initial search on Web of Science, considering keywords related to all modes of CE including their acronyms, yielded about 7000 articles. A first screening in which reviews and irrelevant references were omitted, provided 1200 papers of significance. From these a selection of about 200 was made based on originality, interesting developments and relevance. Notably, studies utilizing electrophoretic principles in microfluidic devices were not included in the present review.Vrazo, M.B., Diefendorf, A.F., Crowley, B.E., Czaja, A.D., 2018. Late Cretaceous marine arthropods relied on terrestrial organic matter as a food source: Geochemical evidence from the Coon Creek Lagerst?tte in the Mississippi Embayment. Geobiology 16, 160-178. Upper Cretaceous Coon Creek Lagerst?tte of Tennessee, USA, is known for its extremely well-preserved mollusks and decapod crustaceans. However, the depositional environment of this unit, particularly its distance to the shoreline, has long been equivocal. To better constrain the coastal proximity of the Coon Creek Formation, we carried out a multiproxy geochemical analysis of fossil decapod (crab, mud shrimp) cuticle and associated sediment from the type section. Elemental analysis and Raman spectroscopy confirmed the presence of kerogenized carbon in the crabs and mud shrimp; carbon isotope (δ13C) analysis of bulk decapod cuticle yielded similar mean δ13C values for both taxa (?25.1‰ and ?26‰, respectively). Sedimentary biomarkers were composed of n-alkanes from C16 to C36, with the short-chain n-alkanes dominating, as well as other biomarkers (pristane, phytane, hopanes). Raman spectra and biomarker thermal maturity indices suggest that the Coon Creek Formation sediments are immature, which supports retention of unaltered, biogenic isotopic signals in the fossil organic carbon remains. Using our isotopic results and published calcium carbonate δ13C values, we modeled carbon isotope values of carbon sources in the Coon Creek Formation, including potential marine (phytoplankton) and terrestrial (plant) dietary sources. Coon Creek Formation decapod δ13C values fall closer to those estimated for terrigenous plants than marine phytoplankton, indicating that these organisms were feeding primarily on terrigenous organic matter. From this model, we infer that the Coon Creek Formation experienced significant terrigenous organic matter input via a freshwater source and thus was deposited in a shallow, nearshore marine environment proximal to the shoreline. This study helps refine the paleoecology of nearshore settings in the Mississippi Embayment during the global climatic shift in the late Campanian–early Maastrichtian and demonstrates for the first time that organic δ13C signatures in exceptionally preserved fossil marine arthropods are a viable proxy for use in paleoenvironmental reconstructions.Wacey, D., Saunders, M., Kong, C., 2018. Remarkably preserved tephra from the 3430 Ma Strelley Pool Formation, Western Australia: Implications for the interpretation of Precambrian microfossils. Earth and Planetary Science Letters 487, 33-43. ～3430 Ma Strelley Pool Formation (SPF), Pilbara, Western Australia contains some of the most diverse microfossil evidence for early life on Earth. Here we report an assemblage of tephra (scoria, tubular pumice, plus vesicular and non-vesicular volcanic glass shards) from two stratigraphic levels in the SPF, including morphotypes that closely resemble previously described microfossils from this unit and elsewhere.Clasts of scoria are characterised by numerous spheroidal vesicles, with subordinate eye- and lens-shaped morphotypes, commonly lined with anatase (TiO2) and small amounts of organic material. Their diameters range from 5–180 μm with 80% in the 10–50 μm range. Fragments of tubular pumice are also lined with anatase +/?+/? carbon and have tube diameters of 5–15 μm. Other volcanic ejecta particles include a multitude of sub-angular shard particles with or without vesicles, plus more rounded vase-shaped, eye-shaped, and hair-like morphologies; once again, most of these are coated by anatase +/?+/? carbon and are several tens of micrometres in size. Many of the tephra fragments are now entirely silicified with no compositional difference between the former volcanic glass, the vesicle infill and the clast matrix. However, some examples retain a partial aluminosilicate composition, either as a vesicle infilling phase or as isolated lath-like grains within the formerly glassy groundmass.Isolated occurrences of some of these tephra morphotypes strongly resemble simple microbial morphologies including pairs and clusters of cells (cf. scoria), filamentous microbes (cf. tubular pumice) and larger sheaths/cysts (cf. sub-rounded glass shards). Furthermore, some tephra-containing clasts occur in a SPF sandstone unit that hosts previously described microfossils, while others are interbedded with chert layers from which microfossils have also been described. In light of our new volcanogenic data, we evaluate the robustness of previous microfossil evidence from the SPF in the East Strelley greenstone belt. We find that the majority of previously illustrated microfossils from this greenstone belt possess multiple features that are consistent with a biological interpretation and are unlikely to be volcanogenic, but at least one previously illustrated specimen is here reinterpreted as volcanic in origin.The importance of this work is that it serves to highlight the common occurrence of volcanogenic microstructures resembling biological fossils (i.e. pseudo-fossils) in Archean environments that are habitable for life. Such structures have until now been largely overlooked in the assessment of putative Precambrian microfossils. Our data show that tephra-derived microstructures should be considered as a null hypothesis in future evaluations of potential signs of life on the early Earth, or on other planets.Wacey, D., Urosevic, L., Saunders, M., George, A.D., 2018. Mineralisation of filamentous cyanobacteria in Lake Thetis stromatolites, Western Australia. Geobiology 16, 203-215. are cited as some of the earliest evidence for life on Earth, but problems remain in reconciling the paucity of microfossils in ancient carbonate examples with the abundance of microbes that help construct modern analogues. Here, we trace the mineralisation pathway of filamentous cyanobacteria within stromatolites from Lake Thetis, Western Australia, providing new insights into microfossil preservation in carbonate stromatolites. Lake Thetis cyanobacteria exhibit a spectrum of mineralisation processes that include early precipitation of Mg-silicates, largely controlled by the morphochemical features of the cyanobacteria, followed by aragonite formation that is inferred to be driven by heterotrophic activity. Fossilised cyanobacteria with high-quality morphological preservation are characterised by a significant volume of authigenic Mg-silicates, which have preferentially nucleated in/on extracellular organic material and on cell walls, and now replicate the region once occupied by the cyanobacterial sheath. In such specimens, aragonite is restricted to the outer sheath margin and parts of the cell interior. Cyanobacteria that display more significant degradation appear to possess a higher ratio of aragonite to Mg-silicate. In these specimens, aragonite forms micronodules in the sheath zone and is spatially associated with the inferred remains of heterotrophic bacteria. Aragonite also occurs as an advancing front from the outer margin of the sheath where it is commonly intergrown with Mg-silicates. Where there is no evidence of Mg-silicates within filaments, the fidelity of microfossil preservation is poor. In these cases, individual filaments may no longer be visible under light microscopy, and little organic material remains, but filament traces remain detectable using electron microscopy due to variations in aragonite texture. These data provide further evidence that authigenic silicate minerals play a crucial role in the fossilisation of micro-organisms; in their absence, carbonate crystal growth potentially mediated by heterotrophic microbial decay may largely obliterate morphological evidence for life within stromatolites, although mineralogical traces may still be detectable using electron microscopy.Wang, B., Qin, Y., Shen, J., Zhang, Q., Wang, G., 2018. Pore structure characteristics of low- and medium-rank coals and their differential adsorption and desorption effects. Journal of Petroleum Science and Engineering 165, 1-12. pores and methane adsorption-desorption characteristics are different between low- and medium-rank coal. For this paper, mercury intrusion porosimetry and isothermal adsorption experiments were carried out on thirteen coal samples with Ro,max between 0.22% and 0.98%. To evaluate the effect of the pore structure on coal permeability, we calculated the multi-scale fractal dimensions according to classic geometry models and discussed factors influencing pore fractals, including metamorphism degree, ash yield, and the content of vitrinite (huminite). Three key pressures in the stage of depressurization were calculated on the basis of Langmuir adsorption theory, and the influencing factors were discussed, including metamorphism degree, fractal dimension, and moisture content. The results show that pores of the coal can be divided into three types according to the pore diameter boundaries of 6,000?nm and 100?nm.The multi-scale fractal dimensions of coal pores (D1, D2, D3) are in the range of 2.341–2.836, 2.041 to 2.476, 2.237 to 2.656, respectively. The pore fractal dimension (D1) is controlled by the degree of metamorphism, and D3 is mainly affected by ash yield, the content of vitrinite (huminite), and the degree of metamorphism. The adsorption of low- and medium-rank coal is a step-by-step control mode under the control of coal metamorphism, in which lignite mainly depends on the moisture content, and long-flame coal-gas coal mainly depends on the adsorption-diffusion hole (<100?nm) pore structure. The lower the fractal dimension of adsorption pore, the better the adsorption. The higher the fractal dimension of the seepage pore, the better the seepage. Four desorption stages of the desorption process are subdivided according to three critical pressure points (starting pressure, transition pressure, and depletion pressure). The different critical pressure points are mainly affected by the degree of coal metamorphism, the pore structure characteristics of the primary seepage pore, and the moisture content. Larger Langmuir volume (VL) and ratio of Langmuir constants (1/PL) are beneficial to earlier advent of steady production stage, whereas it is also possible that the declining production stage may occur ahead of schedule.Wang, C., Houlton, B.Z., Liu, D., Hou, J., Cheng, W., Bai, E., 2018. Stable isotopic constraints on global soil organic carbon turnover. Biogeosciences 15, 987-995. dioxide release during soil organic carbon (SOC) turnover is a pivotal component of atmospheric CO2 concentrations and global climate change. However, reliably measuring SOC turnover rates on large spatial and temporal scales remains challenging. Here we use a natural carbon isotope approach, defined as beta (β), which was quantified from the δ13C of vegetation and soil reported in the literature (176 separate soil profiles), to examine large-scale controls of climate, soil physical properties and nutrients over patterns of SOC turnover across terrestrial biomes worldwide. We report a significant relationship between β and calculated soil C turnover rates (k), which were estimated by dividing soil heterotrophic respiration rates by SOC pools. ln(???β) exhibits a significant linear relationship with mean annual temperature, but a more complex polynomial relationship with mean annual precipitation, implying strong-feedbacks of SOC turnover to climate changes. Soil nitrogen (N) and clay content correlate strongly and positively with ln(???β), revealing the additional influence of nutrients and physical soil properties on SOC decomposition rates. Furthermore, a strong (R2?=?0.76; p?<?0.001) linear relationship between ln(???β) and estimates of litter and root decomposition rates suggests similar controls over rates of organic matter decay among the generalized soil C stocks. Overall, these findings demonstrate the utility of soil δ13C for independently benchmarking global models of soil C turnover and thereby improving predictions of multiple global change influences over terrestrial C-climate feedbackWang, J.-J., Lafrenière, M.J., Lamoureux, S.F., Simpson, A.J., Gélinas, Y., Simpson, M.J., 2018. Differences in riverine and pond water dissolved organic matter composition and sources in Canadian high arctic watersheds affected by active layer detachments. Environmental Science & Technology 52, 1062-1071. warming has caused permafrost thermokarst and disturbances, such as active layer detachments (ALDs), which may alter carbon feedback in Arctic ecosystems. However, it is currently unclear how these disturbances alter DOM biogeochemistry in rivers and ponds in Arctic ecosystems. Water samples from the main river channel, ALD-disturbed/undisturbed tributaries, and disturbed/undisturbed ponds within a catchment in the Canadian High Arctic were collected and analyzed using carbon isotopes and spectroscopic methods. Both river and pond samples had large variations in dissolved organic carbon (DOC) concentrations. Ponds, particularly ALD-disturbed ponds, had much older 14C DOC ages than rivers. Results from δ13C and absorption and fluorescence analyses indicate higher autochthonous contributions in ponds than rivers and increasing autochthonous contributions from upper to lower reaches of the main channel. The disturbed samples had less carbohydrates but more carboxyl-rich alicyclic molecules in 1H nuclear magnetic resonance spectra than undisturbed samples. These ALD-impacted samples also contained less terrestrial-humic-like but more oxidized-quinone-like components in the fluorescence spectra. Interestingly, the disturbed pond DOM displayed the greatest DOM oxidation with ALDs compared to undisturbed areas. Compared to Arctic rivers, small Arctic ponds have DOM predominantly from permafrost and microbial sources and may have a disproportionally stronger positive feedback on climate warming.Wang, J., Zhang, L., Zhao, J., Ai, L., Yang, L., 2018. Variations in permeability along with interfacial tension in hydrate-bearing porous media. Journal of Natural Gas Science and Engineering 51, 141-146. study extends our previous studies on the effects of the IFT on the seepage characteristics in hydrate-bearing porous media using pore network model with X-ray computed tomography. The results indicate that the relative permeability to both methane gas and water decreases as IFT increases. And the influence of the IFT on the two-phase relative permeability increases along with the particle size of the porous media. Moreover, the variation in absolute permeability is always positively related to average pore/throat radii in all type of hydrate-bearing porous media. In addition, the capillary pressure decreases along with IFT.Wang, L., Ye, L., Yu, Y., Jing, C., 2018. Antimony redox biotransformation in the subsurface: Effect of indigenous Sb(V) respiring microbiota. Environmental Science & Technology 52, 1200-1207. microbiological antimonate [Sb(V)] respiration is a newly discovered process regulating the Sb redox transformation in soils. However, little is known about the role microbiological Sb(V) respiration plays in the fate of Sb in the subsurface, especially in the presence of sulfate and electron shuttles. Herein, we successfully enriched a Sb(V) reducing microbiota (SbRM) from the subsurface near an active Sb mine. SbRM was dominated by genus Alkaliphilus (18–36%), Clostridiaceae (17–18%), Tissierella (24–27%), and Lysinibacillus (16–37%). The incubation results showed that SbRM reduced 88% of dissolved Sb(V) to Sb(III), but the total Sb mobility remained the same as in the abiotic control, indicating that SbRM alone did not increase the total Sb release but regulated the Sb speciation in the subsurface. Micro X-ray fluorescence (μ-XRF) analysis suggested the association of Sb and Fe, and electron shuttles such as anthraquinone-2,6-disulfonic disodium salt (AQDS) markedly enhanced the Sb release due to its ability to facilitate Fe mineral dissolution. Sb L-edge and S K-edge X-ray absorption near edge structure (XANES) results demonstrated that indigenous SbRM immobilized Sb via Sb2S3 formation, especially in a sulfur-rich environment. The insights gained from this study shed new light on Sb mobilization and its risk assessment in the subsurface environment.Wang, S., Yang, P., Yang, Z., 2018. Characterization of freeze–thaw effects within clay by 3D X-ray Computed Tomography. Cold Regions Science and Technology 148, 13-21. quantification of moisture content redistribution and physical property change due to freeze–thaw is important for understanding frost heave and thaw settlement of fine-grained soils including clay. This paper presents 3D X-ray Computed Tomography (CT) data for a clay specimen before and after freeze–thaw and physical property data obtained by conventional laboratory testing, and the relationship among the date sets. Undisturbed clay specimens were subject to one-directional freeze–thaw in a closed system under different freezing temperatures to collect 3D X-ray CT images, and the variation in CT image intensity (CTI) before and after freeze–thaw were analyzed to reveal the spatial effects of freeze–thaw. Meanwhile, soil properties including moisture content, void ratio, and dry density were obtained for samples taken from different heights of the specimens with and without freeze–thaw to obtain their changes. Close correlations were observed between the physical property changes and the CTI variation. Linear equations were established between the changes of physical properties and the CTI variation. These equations could potentially be applied for high-resolution quantitative assessment of soil physical property changes due to freeze–thaw by using 3D X-ray CT. This study demonstrates that, compared with traditional test methods, CT scanning can be advantageous in revealing the internal change in soil physical properties due to freeze–thaw quantitatively and nondestructively.Wang, X., He, S., Guo, X., Zhang, B., Chen, X., 2018. The resource evaluation of Jurassic shale in North Fuling area, eastern Sichuan Basin, China. Energy & Fuels 32, 1213-1222. oil and natural gas are commonly found in Jurassic shales in the North Fuling area of Sichuan Bain in China. The main source rocks of the study area are shales from Lower–Middle Jurassic lacustrine layers including the Lianggaoshan Formation (J2l) and the Ziliujing Formation (J1z), which are further divided into the Da’anzhai (J1zD), Ma’anshan (J1zM), and Dongyuemiao (J1zDY) members. Multiple geochemical approaches and tests including kerogen elements, kerogen composition, vitrinite reflectance (VR), total organic carbon (TOC) content test, Rock-Eval pyrolysis, gas chromatography and gas chromatography–mass spectrometry, methane concentration, gas composition, and stable isotopes were employed to determine the geochemical characteristics of the source, oil and gas samples. J1zD shale demonstrates the best abundance and type of organic matter among all four strate and tends to be the most favorable source of hydrocarbons in this area. Crude oil in Jurassic strata is a waxy light oil. Oil samples and shale extracts are nonbiodegraded, and dominated by short-chain n-alkanes, maximizing around C12–C15. Natural gas in Jurassic shales can be categorized as wet gas. δ13C values in different components indicate the gas samples are oil-associated gas which probably originated from the cracking of crude oil. Source correlations suggest the oil and gas are probably generated from J1zD shale. The analysis leads to the general conclusion that the Jurassic shale is more favorable for conventional resources than shale gas.Wang, Y., Chen, J., Pang, X., Zhang, B., Chen, Z., Zhang, G., Luo, G., He, L., 2018. Origin of deep sour natural gas in the Ordovician carbonate reservoir of the Tazhong Uplift, Tarim Basin, northwest China: Insights from gas geochemistry and formation water. Marine and Petroleum Geology 91, 532-549. sour gases are found in the Ordovician carbonate reservoir of the Tazhong Uplift in the Tarim Basin, northwest China. All sour gases in this field are dominated by gas hydrocarbons (C1–C4) with varying amounts of H2S. Most of the gases in the eastern Tazhong are characterized by high gas dryness coefficients (>0.95), 13C-enriched methane (δ13C1 ranging from ?44.6‰ to ?35.8‰), and small difference between values of the δ13C2 and δ13C1 (δ13C2-1). In contrast, the gases in the western Tazhong are characterized by relatively low gas dryness coefficients (mostly?<?0.90), 13C-depleted methane (δ13C1 ranging from ?54.9‰ to ?35.7‰), and high values of δ13C2-1, indicating relatively lower maturity. Gas compositions, carbon isotope ratios, and diamantane data together with thermal pyrolysis experiments using sealed gold tubes suggest that the Ordovician gases in the Tazhong Uplift belong to oil cracking gases mixed with high-maturity 13C-enriched dry gases, which originated from the deeper paleo-reservoirs cracking. The H2S (0.0008%–23.1000%) is attributed to thermochemical sulfate reduction (TSR); in contrast to typical TSR-altered gases, the natural gases in the western Tazhong are characterized by low dryness coefficients, relatively 13C-depleted methane, and high δ13C2-1, suggesting a low degree of TSR alteration. Observations suggest that the H2S contents are generally high in the western Tazhong, with positive correlation to Mg2+ concentrations and total dissolved solids (TDS) in the Ordovician formation water, indicating that TSR has entered early period of SO42? contact ion pairs (CIPs) oxidation. Compared with the eastern Tazhong, the Mg2+ concentrations and TDS in the western Tazhong are higher and form more CIPs that accelerate TSR and produce H2S. In addition, based on the analysis of the Cambrian formation water and the Cambrian gypsiferous salt, TSR might have also exist in the deeper Cambrian reservoirs, and the TSR-altered gases with high content of H2S migrated along faults to Ordovician reservoirs.Wang, Y., Chen, J., Pang, X., Zhang, B., Wang, Y., He, L., Chen, Z., Zhang, G., 2018. Anomalies of natural gas compositions and carbon isotope ratios caused by gas diffusion – A case from the Donghe Sandstone reservoir in the Hadexun Oilfield, Tarim Basin, northwest China. Journal of Asian Earth Sciences 156, 75-89. gases in the Carboniferous Donghe Sandstone reservoir within the Block HD4 of the Hadexun Oilfield, Tarim Basin are characterized by abnormally low total hydrocarbon gas contents (<65%), low methane contents (<10%) and low dryness coefficients (<0.5), and a reversal of the normal trend of carbon isotope ratios, showing δ13C methane (C1)?>?δ13C ethane (C2)?<?δ13C propane (C3)?<?δ13C butane (C4). Specifically, methane is enriched in 13C with the variations in δ13C1 values between gases from Block HD4 and gases from its neighboring blocks reaching 10‰. This type of abnormal gas has never been reported previously in the Tarim Basin and such large variations in δ13C have rarely been observed in other basins globally. Based on a comprehensive analysis of gas geochemical data and the geological setting of the Carboniferous reservoirs in the Hadexun Oilfield, we reveal that the anomalies of the gas compositions and carbon isotope ratios in the Donghe Sandstone reservoir are caused by gas diffusion through the poorly-sealed caprock rather than by pathways such as gas mixing, microorganism degradation, different kerogen types or thermal maturity degrees of source rocks. The documentation of an in-reservoir gas diffusion during the post entrapment process as a major cause for gas geochemical anomalies may offer important insight into exploring natural gas resources in deeply buried sedimentary basins.Wang, Y., Liang, J., Wang, J., Gao, S., 2018. Combining stable carbon isotope analysis and petroleum-fingerprinting to evaluate petroleum contamination in the Yanchang oilfield located on loess plateau in China. Environmental Science and Pollution Research 25, 2830-2841. study evaluated petroleum contamination in the Yanchang (Shaanxi Yanchang Petroleum (Group) Co., Ltd.) oilfield, located in the loess plateau region of northern Shaanxi, China. Surface soil and sediment samples were collected from the wasteland, farmland, and riverbed in this area to assess the following parameters: total petroleum hydrocarbon (TPH), n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and carbon isotope ratios (δ13C). The results showed that TPH and PAH levels in the study area were 907–3447?mg/kg and 103.59–563.50?μg/kg, respectively, significantly higher than the control samples (TPH 224?mg/kg, PAHs below method quantification limit, MQL). Tests using δ13C to detect modified TPH (2238.66 to 6639.42?mg/kg) in the wastelands adjacent to the oil wells revealed more significant contamination than tests using extraction gravimetric analysis. In addition, “chemical fingerprint” indicators, such as low to high molecular weight (LMW/HMW) hydrocarbons, carbon preference index (CPI), and pristine/phytane (Pr/Ph), further confirmed the presence of heavy petroleum contamination and weathering. This has resulted in a nutrient imbalance and unsuitable pH and moisture conditions for microbial metabolic activities. This study evaluates petroleum contamination, which can inform contamination remediation on a case by case basis.Wang, Z., Gao, D., Fang, J., 2018. Numerical simulation of RF heating heavy oil reservoir based on the coupling between electromagnetic and temperature field. Fuel 220, 14-24. present, a technology of RF (radio frequency) heating is being investigated for enhanced heavy oil recovery, but continued high temperature appears near wellbore, which may destroy the wellbore integrity and RF apparatus. This paper first introduces a novel RF apparatus composed of antenna arrays for heating the heavy oil reservoir, and then the temperature distribution is calculated based on the coupling between electromagnetic and temperature field. To alleviate the high temperature in the vicinity of wellbore, two solutions are proposed: (1) a sleeve made of PTFE (polytetrafluoroethylene) is applied to the outside of the RF apparatus; (2) for improving accuracy of temperature calculation, thermos-physical parameters of reservoir, which are depended on the temperature, are considered specifically in the heat transfer equation and wave equation. Finally, the effect of properties of reservoir and the relative permittivity of sleeve on temperature distribution are investigated. Calculation results indicate that relative permittivity of sleeve has a tremendous influence on temperature distribution, and maximum temperature declines nearby the wellbore as the diminution of relative permittivity, moreover, the positions with highest temperature are moving far from the wellbore. When the parameters of specific heat and thermal conductivity are variable, the maximum temperature near the wellbore is lower than the temperature calculated by constant parameters. Variable relative permittivity of water can’t decrease the temperature around the wellbore.Ward, C.P., Sharpless, C.M., Valentine, D.L., French-McCay, D.P., Aeppli, C., White, H.K., Rodgers, R.P., Gosselin, K.M., Nelson, R.K., Reddy, C.M., 2018. Partial photochemical oxidation was a dominant fate of Deepwater Horizon surface oil. Environmental Science & Technology 52, 1797-1805. the Deepwater Horizon (DWH) blowout in 2010, oil floated on the Gulf of Mexico for over 100 days. In the aftermath of the blowout, substantial accumulation of partially oxidized surface oil was reported, but the pathways that formed these oxidized residues are poorly constrained. Here we provide five quantitative lines of evidence demonstrating that oxidation by sunlight largely accounts for the partially oxidized surface oil. First, residence time on the sunlit sea surface, where photochemical reactions occur, was the strongest predictor of partial oxidation. Second, two-thirds of the partial oxidation from 2010 to 2016 occurred in less than 10 days on the sunlit sea surface, prior to coastal deposition. Third, multiple diagnostic biodegradation indices, including octadecane to phytane, suggest that partial oxidation of oil on the sunlit sea surface was largely driven by an abiotic process. Fourth, in the laboratory, the dominant photochemical oxidation pathway of DWH oil was partial oxidation to oxygenated residues rather than complete oxidation to CO2. Fifth, estimates of partial photo-oxidation calculated with photochemical rate modeling overlap with observed oxidation. We suggest that photo-oxidation of surface oil has fundamental implications for the response approach, damage assessment, and ecosystem restoration in the aftermath of an oil spill, and that oil fate models for the DWH spill should be modified to accurately reflect the role of sunlight.Ward, L., Hemp, J., Shih, P., McGlynn, S., Fischer, W., 2018. Evolution of phototrophy in the Chloroflexi phylum driven by horizontal gene transfer. Frontiers in Microbiology 9, 260. doi: 10.3389/fmicb.2018.00260 evolutionary mechanics behind the extant distribution of photosynthesis is a point of substantial contention, with hypotheses ranging from its presence in the last universal common ancestor and massive gene loss in most lineages, to a later origin followed by extensive horizontal gene transfer into the extant phototrophic clades, or intermediate scenarios that incorporate aspects of both end-members. Here, we report the discovery of ten new draft genome sequences of members of the Chloroflexi phylum from metagenomic sequencing of microbial mats in Japanese hot springs; these new taxa form a metabolically diverse, monophyletic clade sister to the Anaerolineae class that we term Candidatus Thermofonsia. Comparisons of organismal (based on conserved ribosomal) and phototrophy (reaction center and bacteriochlorophyll synthase) protein phylogenies throughout the Chloroflexi demonstrate that this new class includes two lineages that acquired phototrophy via horizontal gene transfer (HGT) independently from different ancestral donors within the classically phototrophic Chloroflexia class. These results illustrate a complex history of phototrophy within this group, with metabolic innovation tied to HGT. These observations do not support simple hypotheses for the evolution of photosynthesis that require massive character loss from many clades; rather, HGT appears to be the defining mechanic for the distribution of phototrophy in many of the extant clades in which it appears.Webster, L., Russell, M., Shepherd, N., Packer, G., Dalgarno, E.J., Neat, F., 2018. Monitoring of polycyclic aromatic hydrocarbons (PAHs) in Scottish deepwater environments. Marine Pollution Bulletin 128, 456-459. aromatic hydrocarbons (PAHs) were measured in environmental samples (sponges, fish and sediment) collected in 2014 and 2016 from the Faroe-Shetland Channel and Rosemary Bank Seamount. These data could be used to provide a baseline against which any changes can be assessed in the event of an oil spill and contribute to any environmental impact assessment. Concentrations in all samples were low, often below the detection limits, and were typical of reference sites. Sponges can be used as an alternative indicator species to mussels for monitoring PAHs in the marine environment as they can accumulate PAHs from both the dissolved and particulate phase. PAH concentrations in marine sponges from Scottish water have not previously been reported. Concentrations were low, but contained a higher proportion of heavier 4- to 6-ring PAHs compared to the fish samples.Wen, Y., Talebi, M., Amos, R.I.J., Szucs, R., Dolan, J.W., Pohl, C.A., Haddad, P.R., 2018. Retention prediction in reversed phase high performance liquid chromatography using quantitative structure-retention relationships applied to the Hydrophobic Subtraction Model. Journal of Chromatography A 1541, 1-11. Structure-Retention Relationships (QSRR) methodology combined with the Hydrophobic Subtraction Model (HSM) have been utilized to accurately predict retention times for a selection of analytes on several different reversed phase liquid chromatography (RPLC) columns. This approach is designed to facilitate early prediction of co-elution of analytes, for example in pharmaceutical drug discovery applications where it is advantageous to predict whether impurities might be co-eluted with the active drug component. The QSRR model utilized VolSurf+ descriptors and a Partial Least Squares regression combined with a Genetic Algorithm (GA-PLS) to predict the solute coefficients in the HSM. It was found that only the hydrophobicity (η' H) term in the HSM was required to give the accuracy necessary to predict potential co-elution of analytes. Global QSRR models derived from all 148 compounds in the dataset were compared to QSRR models derived using a range of local modelling techniques based on clustering of compounds in the dataset by the structural similarity of compounds (as represented by the Tanimoto similarity index), physico-chemical similarity of compounds (represented by log D), the neutral, acidic, or basic nature of the compound, and the second dominant interaction between analyte and stationary phase after hydrophobicity. The global model showed reasonable prediction accuracy for retention time with errors of 30?s and less for up to 50% of modeled compounds. The local models for Tanimoto, nature of the compound and second dominant interaction approaches all exhibited prediction errors less than 30?s in retention time for nearly 70% of compounds for which models could be derived. Predicted retention times of five representative compounds on nine reversed-phase columns were compared with known experimental retention data for these columns and this comparison showed that the accuracy of the proposed modelling approach is sufficient to reliably predict the retention times of analytes based only on their chemical structures.Westerhold, T., R?hl, U., Donner, B., Frederichs, T., Kordesch, W.E.C., Bohaty, S.M., Hodell, D.A., Laskar, J., Zeebe, R.E., 2018. Late Lutetian Thermal Maximum—Crossing a thermal threshold in Earth's climate system? Geochemistry, Geophysics, Geosystems 19, 73-82. and deciphering transient global warming events triggered by massive release of carbon into Earth's ocean-atmosphere climate system in the past are important for understanding climate under elevated pCO2 conditions. Here we present new high-resolution geochemical records including benthic foraminiferal stable isotope data with clear evidence of a short-lived (30 kyr) warming event at 41.52 Ma. The event occurs in the late Lutetian within magnetochron C19r and is characterized by a ～2°C warming of the deep ocean in the southern South Atlantic. The magnitudes of the carbon and oxygen isotope excursions of the Late Lutetian Thermal Maximum are comparable to the H2 event (53.6 Ma) suggesting a similar response of the climate system to carbon cycle perturbations even in an already relatively cooler climate several million years after the Early Eocene Climate Optimum. Coincidence of the event with exceptionally high insolation values in the Northern Hemisphere at 41.52 Ma might indicate that Earth's climate system has a thermal threshold. When this tipping point is crossed, rapid positive feedback mechanisms potentially trigger transient global warming. The orbital configuration in this case could have caused prolonged warm and dry season leading to a massive release of terrestrial carbon into the ocean-atmosphere system initiating environmental change.White, D.J., 2018. 3D architecture of the Aquistore reservoir: Implications for CO2 flow and storage capacity. International Journal of Greenhouse Gas Control 71, 74-85. assessment of the Aquistore CO2 storage reservoir has been conducted using a 30?km2 3D seismic volume and a suite of well logs. 3D porosity was calculated using acoustic impedance from model-based seismic inversion and a log-based porosity-impedance relation. The reservoir has a mean thickness of 219?m ±??=?3% comprising 51% of pay. Strata dip at ～1.75% SSE and include a prominent SSE-NNW structural fabric dominated by a ridge that corresponds to a Precambrian basement fault and overlying flexure. Porosity maps for Black Island and Deadwood reservoir zones show mean interval porosities of 0.071?±???=?18% and 0.075?±???=?9%, respectively with a weak degree of directionality that is sub-parallel to the strong NNW-SSE structural trends. Lateral spread of injected CO2 will be strongly affected by the NNW-trending structural relief and bulk porosity/permeability trends. Local topographic channels may control CO2 flow particularly when injection rates are low and local closed topographic structures may constitute traps for CO2. CO2 static capacity estimates from well-based mean values are less than comparable seismic-based estimates by <15% due to porosity differences and <5% due to thickness differences. Variations in the Deadwood thickness of up to 25?m from the mean value would have resulted in capacity estimate differences of up to 25% if an alternate well location had been chosen.Wierzchos, J., Casero, M.C., Artieda, O., Ascaso, C., 2018. Endolithic microbial habitats as refuges for life in polyextreme environment of the Atacama Desert. Current Opinion in Microbiology 43, 124-131. extremely harsh conditions of hyperarid deserts are a true challenge for microbial life. Microorganisms thriving in such polyextreme environments are fascinating as they can tell us more about life, its strategies and its boundaries than other groups of organisms. The Atacama Desert (North Chile) holds two world records of extreme environmental characteristics: the lowest rainfall and greatest surface ultraviolet radiation and total solar irradiance ever measured on Earth. Despite these limiting conditions for life, we recently identified several remarkable examples of endolithic habitats colonized by phototrophic and heterotrophic microorganisms in the hyperarid core of the Atacama Desert.Wilkins, R.W.T., Sherwood, N., Li, Z., 2018. RaMM (Raman maturity method) study of samples used in an interlaboratory exercise on a standard test method for determination of vitrinite reflectance on dispersed organic matter in rocks. Marine and Petroleum Geology 91, 236-250. (Raman maturity method) is a thermal maturity tool for humic macerals in coals or as dispersed organic matter (DOM), expressed in equivalent vitrinite reflectance (EqVR). The EqVR values are based on a recently established calibration according to multi-linear regressions of selected parameters from Raman spectra of vitrinite and inertinite in a suite of Australian coals with vitrinite reflectance (VR) in the range 0.4–2.5%. The study contributes to the application of Raman spectroscopy for thermal maturity determinations as applicable to the petroleum exploration industry and researched by many groups worldwide.A suite of samples to apply the technique was made available from an interlaboratory round robin exercise on application of ASTM D7708, a method for determination of VR of DOM in sedimentary rocks. This exercise involved the distribution of two sets of six unknown rock samples to all participating laboratories. Collated VR results from some samples of the first set, having high maturities and low organic matter (OM) contents, showed a disturbingly high degree of scatter. Although general agreement exists between RaMM determinations and the average of ‘mean random’ VR values determined at the various laboratories, some important differences emerged for some samples in the range EqVR?=?1.2–1.8%.On RaMM diagrams, which involve plots of EqVRs derived from the two regression equations defining the method, the pattern of distribution of vitrinite and inertinite changes with thermal maturity for ‘normal’ coals and with OM composition in subhydrous versus perhydrous coals.Most of the round robin samples contained solid bitumens having reflectances close to those of the associated vitrinite. Measurements taken from solid bitumen were avoided as much as possible, but because the RaMM study was done in air medium, some contamination of the humic maceral data was inevitable. Many of the solid bitumens and other potentially complicating components such as Tasmanites-related alginite can be identified on the RaMM diagram and eliminated from RaMM results for lower maturity samples (EqVR?<?1.4%) whereas solid bitumen and humic macerals appear to provide similar EqVR for higher maturity samples (EqVR?>?1.8%).The humic DOM of marine samples having EqVR >1.0% has spectral properties that differ from those of humic macerals of the same maturity in terrestrially deposited rocks; this could possibly explain any discrepancies between RaMM EqVR and VR data for the marine rocks.The presence of contaminating solid bitumen with reflectance similar to that of vitrinite, is the main complicating factor for thermal maturity evaluation using either VR or RaMM analyses of gas shales and tight oil reservoir rocks. To enable the best results from RaMM studies of these types of rocks, a preliminary study of the solid bitumen component should be carried out to determine its field on the RaMM diagram with the object of eliminating contaminating solid bitumen data from EqVR calculations.Williams, G.E., Schmidt, P.W., 2018. Shuram–Wonoka carbon isotope excursion: Ediacaran revolution in the world ocean's meridional overturning circulation. Geoscience Frontiers 9, 391-402. late Ediacaran Shuram–Wonoka excursion, with δ13Ccarb values as low as –12‰ (PDB) in marine-shelf deposits and spanning up to 10 Myr, is the deepest and most protracted δ13Ccarb negative anomaly recognised in Earth history. The excursion formed on at least four continents in low (≤32°) palaeolatitudes, and in China is associated with a major phosphogenic event. Global and intrabasinal correlation, magnetostratigraphy, isotope conglomerate tests and further geochemical data are consistent with a primary or syn-depositional origin for the excursion. Continental-margin phosphorites are generated by oceanic upwelling driven by surface winds, and δ13Ccarb negative anomalies are explicable by oceanic upwelling of 13C-depleted deep oceanic waters, arguing that a feature common to these exceptional Ediacaran events was unprecedented perturbation of the world ocean. These events occurred during the transition from an alien Proterozoic world marked by low-palaeolatitude glaciation near sea level and strong seasonality to the familiar Phanerozoic Earth with circum-polar glaciation and temperate climate, suggesting that the Shuram–Wonoka excursion is related to this profound change in Earth's climate system. Of various hypotheses for Proterozoic low-palaeolatitude glaciation, only the high obliquity (>54°) hypothesis, which posits secular decrease in obliquity to near the present-day value (23.5°) during the Ediacaran, predicts an unparalleled revolution in the Ediacaran world ocean. The obliquity controls the sense of the world ocean's meridional overturning circulation, which today is driven by the sinking of cold, dense water at the poles and upwelling driven by zonal surface winds. When the decreasing obliquity passed the critical value of 54° during the Ediacaran the meridional temperature gradient reversed, with the equator becoming warmer than the poles and Hadley low-latitude (<30°–35°) atmospheric zonal circulation reversing. This reversal of the temperature gradient is unique to the Ediacaran Period and caused reversal of the oceanic meridional overturning circulation, with upwelling of anoxic, 13C-depleted deep oceanic waters producing a deeply negative and protracted δ13Ccarb signature on late Ediacaran marine-shelf deposits.Witkowski, B., Duchnowicz, A., Ganeczko, M., Laudy, A., Gierczak, T., Biesaga, M., 2018. Identification of proteins, drying oils, waxes and resins in the works of art micro-samples by chromatographic and mass spectrometric techniques. Journal of Separation Science 41, 630-638. method for simultaneous identification of proteins, drying oils, waxes, and resins in the works-of-art samples was developed. Liquid chromatography with mass spectrometry and gas chromatography with mass spectrometry were used to identify natural materials most frequently encountered in historical paintings. Protein binders were extracted with ammonia and purified using miniaturized solid-phase microextraction (Omix tips) to efficiently suppress matrix interferences. Zwitterionic stationary phase was used for separation of 16 underivatized amino acids analysis with hydrophilic interaction liquid chromatography that was subsequently quantified with liquid chromatography with mass spectrometry. Gas chromatography with mass spectrometry was used to analyze drying oils, waxes, and resins after one-step saponification/transmethylation with (m-trifluoromethylphenyl)trimethylammonium hydroxide (Meth-Prep II). While the drawback of this reagent is low reactivity towards hydroxyl groups, sample pretreatment was much simpler as compared to the other methods. Fatty acids derivatization with the Meth-Prep II reagent was compared with their silylation using N,O-bis(trimethylsilyl) trifluoroacetamide/trimethylchlorosilane mixture. It was concluded that fatty acids analysis as their methyl esters instead of trimethylsilyl esters had a minor impact on the method sensitivity. The developed method was used to analyze samples from 16th and 17th century historical paintings.Wolbach, W.S., Ballard, J.P., Mayewski, P.A., Adedeji, V., Bunch, T.E., Firestone, R.B., French, T.A., Howard, G.A., Israde-Alcántara, I., Johnson, J.R., Kimbel, D., Kinzie, C.R., Kurbatov, A., Kletetschka, G., LeCompte, M.A., Mahaney, W.C., Melott, A.L., Maiorana-Boutilier, A., Mitra, S., Moore, C.R., Napier, W.M., Parlier, J., Tankersley, K.B., Thomas, B.C., Wittke, J.H., West, A., Kennett, J.P., 2018. Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ～12,800 years ago. 1. Ice cores and glaciers. The Journal of Geology 126, 165-184. Younger Dryas boundary (YDB) cosmic-impact hypothesis is based on considerable evidence that Earth collided with fragments of a disintegrating ≥100-km-diameter comet, the remnants of which persist within the inner solar system ～12,800 y later. Evidence suggests that the YDB cosmic impact triggered an “impact winter” and the subsequent Younger Dryas (YD) climate episode, biomass burning, late Pleistocene megafaunal extinctions, and human cultural shifts and population declines. The cosmic impact deposited anomalously high concentrations of platinum over much of the Northern Hemisphere, as recorded at 26 YDB sites at the YD onset, including the Greenland Ice Sheet Project 2 ice core, in which platinum deposition spans ～21 y (～12,836–12,815 cal BP). The YD onset also exhibits increased dust concentrations, synchronous with the onset of a remarkably high peak in ammonium, a biomass-burning aerosol. In four ice-core sequences from Greenland, Antarctica, and Russia, similar anomalous peaks in other combustion aerosols occur, including nitrate, oxalate, acetate, and formate, reflecting one of the largest biomass-burning episodes in more than 120,000 y. In support of widespread wildfires, the perturbations in CO2 records from Taylor Glacier, Antarctica, suggest that biomass burning at the YD onset may have consumed ～10 million km2, or ～9% of Earth’s terrestrial biomass. The ice record is consistent with YDB impact theory that extensive impact-related biomass burning triggered the abrupt onset of an impact winter, which led, through climatic feedbacks, to the anomalous YD climate episode.Wolbach, W.S., Ballard, J.P., Mayewski, P.A., Parnell, A.C., Cahill, N., Adedeji, V., Bunch, T.E., Domínguez-Vázquez, G., Erlandson, J.M., Firestone, R.B., French, T.A., Howard, G., Israde-Alcántara, I., Johnson, J.R., Kimbel, D., Kinzie, C.R., Kurbatov, A., Kletetschka, G., LeCompte, M.A., Mahaney, W.C., Melott, A.L., Mitra, S., Maiorana-Boutilier, A., Moore, C.R., Napier, W.M., Parlier, J., Tankersley, K.B., Thomas, B.C., Wittke, J.H., West, A., Kennett, J.P., 2018. Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ～12,800 years ago. 2. Lake, marine, and terrestrial sediments. The Journal of Geology 126, 185-205. 1 of this study investigated evidence of biomass burning in global ice records, and here we continue to test the hypothesis that an impact event at the Younger Dryas boundary (YDB) caused an anomalously intense episode of biomass burning at ～12.8 ka on a multicontinental scale (North and South America, Europe, and Asia). Quantitative analyses of charcoal and soot records from 152 lakes, marine cores, and terrestrial sequences reveal a major peak in biomass burning at the Younger Dryas (YD) onset that appears to be the highest during the latest Quaternary. For the Cretaceous-Tertiary boundary (K-Pg) impact event, concentrations of soot were previously utilized to estimate the global amount of biomass burned, and similar measurements suggest that wildfires at the YD onset rapidly consumed ～10 million km2 of Earth’s surface, or ～9% of Earth’s biomass, considerably more than for the K-Pg impact. Bayesian analyses and age regressions demonstrate that ages for YDB peaks in charcoal and soot across four continents are synchronous with the ages of an abundance peak in platinum in the Greenland Ice Sheet Project 2 (GISP2) ice core and of the YDB impact event (12,835–12,735 cal BP). Thus, existing evidence indicates that the YDB impact event caused an anomalously large episode of biomass burning, resulting in extensive atmospheric soot/dust loading that triggered an “impact winter.” This, in turn, triggered abrupt YD cooling and other climate changes, reinforced by climatic feedback mechanisms, including Arctic sea ice expansion, rerouting of North American continental runoff, and subsequent ocean circulation changes.Wu, W., Shi, X., Liu, J., Li, D., Xie, J., Zhao, S., Ji, C., Hu, Y., Guo, Y., 2017. Accumulation conditions and exploration potential of Wufeng-Longmaxi Formations shale gas in Wuxi area, Northeastern Sichuan Basin, China. Journal of Natural Gas Geoscience 2, 263-271. Formations shale gas is a new exploration field in Wuxi area, Sichuan Basin, China. Some geological parameters related to shale gas evaluation of the new exploration wells in Wuxi area have been studied, including shale reservoir, gas-bearing, geochemical and paleontological characteristics. The study suggests that the original shale gas generation conditions of the area were good, but later this area went through serious and multi-phase tectonic damage. The major evidences include that: the δ13C2 value of shale gas is obviously higher than that in areas with the same maturity, indicating the shale gas is mainly late kerogen cracking gas and high hydrocarbon expulsion efficiency; the porosity of shale in Wuxi area is very low because of strong tectonic movements and lack of retained oil in the shale; some shale cores near faults even show very weak metamorphic characteristics with intense cleavage, and the epidermis of graptolite fossils was pyrolyzed. The comprehensive study shows shale gas in Wuxi area has prospective resources, but the possibility to get scale commercial production in recent time is very low.Wu, W., Zheng, H., Hou, M., Ge, Q., 2018. The 5.5 cal ka BP climate event, population growth, circumscription and the emergence of the earliest complex societies in China. Science China Earth Sciences 61, 134-148. emergence of complex society is a milestone in the history of human society evolution. China is one of the few regions in the world where the earliest complex society appeared; however, its driving mechanisms remain unresolved. On the base of available evidence from both archaeology and Holocene climate, in combination with agency theory, this study attempts to address the driving mechanisms for the simultaneous emergence of complex societies in multiple areas of China around 5.5 cal ka BP. It is hypothesized that three factors, including climate change, population growth, and circumscription, jointly act and cause regional population-resource imbalance and trigger inter-group conflicts and wars. Such competitions provide the opportunity for some power-pursuing agents to break the restriction of social leveling mechanism and to become the centralized decision-making leaders, which further lead to the emergence of incipient large-scale complex societies. Increase in extreme climate events during 6.0–5.0 cal ka BP cooling period causes frequent occurrence of resource stress and increase in the frequency of inter-group competitions, which creates conditions for the legitimation, institutionalization, and persistence of centralized leadership, and finally leads to the formation of persistent institutionalized inequity. Our research result can explain not only the process and mechanism of complex society formation, but also two phenomena which cannot be reasonably explained by previous theories, that are, why the earliest complex societies in China emerge around 5.5 cal ka BP, and why they appear simultaneously in multiple regions.Wu, X., Chen, Y., Zhao, G., Du, X., Zeng, H., Wang, P., Wang, Y., Hu, Y., 2017. Evaluation of source rocks in the 5th member of the Upper Triassic Xujiahe Formation in the Xinchang Gas Field, the Western Sichuan Depression, China. Journal of Natural Gas Geoscience 2, 253-262. 5th member of the Upper Triassic Xujiahe Formation (T3x5) is one of the important targets for terrigenous natural gas exploration in the Xinchang Gas Field in the Western Sichuan Depression, however, the quality of the T3x5 source rocks is poorly studied and the understanding of it is controversial. Studies have been conducted on the development and organic geochemical characteristics of the T3x5 mudstone in the Xinchang Gas Field, and the results indicate that, the T3x5 mudstone in the Xinchang Gas Field display an average thickness of 285.3 m, and the thickness of each submember increases from north to south. The average TOC content, hydrocarbon potential (S1+S2) and chloroform bitumen “A” content of T3x5 mudstone are 2.17%, 2.26 mg/g and 0.264‰, respectively, with the organic abundance mainly reaching the standard of medium source rocks. The kerogen type index (TI) is lower than 0 with the mean δ13C value of ?25.0‰, indicating mainly humic and sapropelic-humic types of organic matters. The average vitrinite reflectance (RO) value is 1.17%, indicating the stage after the peak of oil generation. The gas generation intensity of T3x5 mudstone is generally in the range of (3–16) × 108 m3/km2, which suggests the resource basis for the generation of medium-small gas fields. The total amount of natural gas generated by T3x5 mudstone in the Xinchang Gas Field is relatively low, and the generated gas cannot completely displace the water in the formation, therefore, the fullness of gas in the reservoirs is generally low, which causes the simultaneous production of gas and water and the low gas production in the process of production test.Wu, Z., Li, Y., Sun, X., Li, M., Jia, R., 2018. Experimental study on the gas phase permeability of montmorillonite sediments in the presence of hydrates. Marine and Petroleum Geology 91, 373-380. is a key parameter influencing fluids flow capacity and the gas production rate of the marine hydrate-bearing sediments. In this study, a series of experiments were carried out to find out the dependence of the gas phase permeability of montmorillonite on different hydrate saturations at effective axial stresses of 1?MPa, 3?MPa. And an experimental study of the decomposition of methane hydrate (MH) by depressurization was carried out. It is found that with the increase of gas hydrate saturation, the gas phase permeability of montmorillonite shows a trend of decreasing first and then increasing, due to the effect of blockage of hydrate particles and the increase of pores in inter-aggregate zones during methane hydrate formation. Furthermore, the gas phase permeability of clay clearly decreases gradually with the increasing decomposition time under different hydrate saturations, due to the formation of the bound water and the swelling of clay. The magnitude of CH4 coefficient of permeability Ka and that of transmission D? reache 10?7and 10?8, respectively. Ka is also known as hydraulic conductivity in the Darcy law. It is defined as the unit flow rate under the unit hydraulic gradient, indicating the difficulty of the fluid passing through the pore skeleton. And D?is the coefficient of transmission based on a modified form of Fick's law, which is a function of the volume-mass properties of the soil and the gas density. After the complete decomposition of the hydrate, the permeability coefficient Ka decreases with the increase of initial hydrate saturation when 4.02%≤Sh≤15.15%. However, 15.15%≤Sh≤27.26%, the values of Ka increase with the increase of initial hydrate saturation. These experiments helped us understand some important aspects of MH behavior such as saturation of hydrate formation, effective stress, and permeability change during decomposition. This work could be useful to research on the production efficiency of marine gas hydrate reservoir.Xi, L., Qiao, N., Zhang, J., Li, J., Liu, D., You, J., Liu, J., 2018. Deinococcus petrolearius sp. nov. isolated from crude oil recovery water in China. Antonie van Leeuwenhoek 111, 353-360. Gram-stain positive, non-motile, spherical, red-pigmented and facultatively anaerobic bacterium, designated strain 6.1T, was isolated from a crude oil recovery water sample from the Huabei oil field in China. The novel strain exhibited tolerance of UV irradiation (>?1000?J?m?2). Based on 16S rRNA gene sequence comparisons, strain 6.1T shows high similarity to Deinococcus citri DSM 24791T (98.1%) and Deinococcus gobiensis I-0T (97.8%), with less than 93.5% similarity to other closely related taxa. The major cellular fatty acids were identified as summed feature 3 (C16:1 ω7c and/or iso-C15:0 2-OH), followed by iso-C17:1 ω9c and C16:0. The polar lipid profile was found to contain phospholipids, glycolipids, phosphoglycolipids and aminophospholipids. The predominant respiratory quinone was identified as MK-8. The DNA G?+?C content was determined to be 68.3?mol %. DNA–DNA hybridization between strain 6.1T and D. citri DSM 24791T was 45.6?±?7.1% and with D. gobiensis I-OT was 36.6?±?4.7%. On the basis of phylogenetic, chemotaxonomic and phenotypic data, we conclude strain 6.1T represents a novel species of the genus Deinococcus, for which we propose the name Deinococcus petrolearius sp. nov. The type strain is 6.1T (=?CGMCC 1.15053T?=?KCTC 33744T).Xie, W., Luo, H., Murugapiran, S.K., Dodsworth, J.A., Chen, S., Sun, Y., Hedlund, B.P., Wang, P., Fang, H., Deng, M., Zhang, C.L., 2018. Localized high abundance of Marine Group II archaea in the subtropical Pearl River Estuary: implications for their niche adaptation. Environmental Microbiology 20, 734-754. Group II archaea are widely distributed in global oceans and dominate the total archaeal community within the upper euphotic zone of temperate waters. However, factors controlling the distribution of MGII are poorly delineated and the physiology and ecological functions of these still-uncultured organisms remain elusive. In this study, we investigated the planktonic MGII associated with particles and in free-living forms in the Pearl River Estuary (PRE) over a 10-month period. We detected high abundance of particle-associated MGII in PRE (up to ～108 16S rRNA gene copies/l), which was around 10-fold higher than the free-living MGII in the same region, and an order of magnitude higher than previously reported in other marine environments. 10‰ salinity appeared to be a threshold value for these MGII because MGII abundance decreased sharply below it. Above 10‰ salinity, the abundance of MGII on the particles was positively correlated with phototrophs and MGII in the surface water was negatively correlated with irradiance. However, the abundances of those free-living MGII showed positive correlations with salinity and temperature, suggesting the different physiological characteristics between particle-attached and free-living MGIIs. A nearly completely assembled metagenome, MGIIa_P, was recovered using metagenome binning methods. Compared with the other two MGII genomes from surface ocean, MGIIa_P contained higher proportions of glycoside hydrolases, indicating the ability of MGIIa_P to hydrolyse glycosidic bonds in complex sugars in PRE. MGIIa_P is the first assembled MGII metagenome containing a catalase gene, which might be involved in scavenging reactive oxygen species generated by the abundant phototrophs in the eutrophic PRE. Our study presented the widespread and high abundance of MGII in the water columns of PRE, and characterized the determinant abiotic factors affecting their distribution. Their association with heterotrophs, preference for particles and resourceful metabolic traits indicate MGII might play a significant role in metabolising organic matters in the PRE and other temperate estuarine systems.Xie, Z.-X., Chen, F., Zhang, S.-F., Wang, M.-H., Zhang, H., Kong, L.-F., Dai, M.-H., Hong, H.-S., Lin, L., Wang, D.-Z., 2018. Metaproteomics of marine viral concentrates reveals key viral populations and abundant periplasmic proteins in the oligotrophic deep chlorophyll maximum of the South China Sea. Environmental Microbiology 20, 477-491. concentrates (VCs), containing bioinformative DNA and proteins, have been used to study viral diversity, viral metagenomics and virus–host interactions in natural ecosystems. Besides viruses, VCs also contain many noncellular biological components including diverse functional proteins. Here, we used a shotgun proteomic approach to characterize the proteins of VCs collected from the oligotrophic deep chlorophyll maximum (DCM) of the South China Sea. Proteins of viruses infecting picophytoplankton, that is, cyanobacteria and prasinophytes, and heterotrophic bacterioplankton, such as SAR11 and SAR116, dominated the viral proteome. Almost no proteins from RNA viruses or known gene transfer agents were detected, suggesting that they were not abundant at the sampling site. Remarkably, nonviral proteins made up about two thirds of VC proteins, including overwhelmingly abundant periplasmic transporters for nutrient acquisition and proteins for diverse cellular processes, that is, translation, energy metabolism and one carbon metabolism. Interestingly, three 56 kDa selenium-binding proteins putatively involved in peroxide reduction from gammaproteobacteria were abundant in the VCs, suggesting active removal of peroxide compounds at DCM. Our study demonstrated that metaproteomics provides a valuable avenue to explore the diversity and structure of the viral community and also the pivotal biological functions affiliated with microbes in the natural environment.Xu, B., Zhang, L., Ma, F., Zhang, W., Wang, X., Zhang, Q., Luo, D., Ma, H., Li, P., 2018. Determination of free steroidal compounds in vegetable oils by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry. Food Chemistry 245, 415-425. method based on comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC?×?GC-TOF/MS) was developed to analyze steroidal compounds in vegetable oils, which could provide better separation and higher sensitivity than conventional one dimensional gas chromatography, and allowed determination of 31 sterols and triterpene alcohols in one injection. Furthermore, the approach also permitted separation and detection of small amounts of other compounds (may be steroidal compounds whose molecular structures have not been confirmed), which were obscured in the lower-resolution single-column technique. With the help of the GC?×?GC system, a more elaborate and complete information regarding the distributions and concentrations of free phytosterols and triterpene alcohols in safflower seed oil, soybean oil, rapeseed oil, sunflower seed oil and peanut oil were obtained. The proposed method could potentially open a new opportunity for the more in-depth knowledge of the steroidal compounds of vegetable oils.Xu, J., Liu, X., Wang, Q., Huang, S., Yin, L., Xu, J., Liu, X., Jiang, R., Zhu, F., Ouyang, G., 2018. Improving the sensitivity of solid-phase microextraction by reducing the volume of off-line elution solvent. Analytical Chemistry 90, 1572-1577. microextraction (SPME) coupled with liquid chromatograph (LC) is widely used to detect polar and ionic organic compounds, including various pharmaceuticals and endogenous bioactive compounds. In this study, a small-sized insert tube for use in the commercial autosampler vial was designed for eluting the extracted analytes from SPME fibers for LC analysis. By using this custom-made insert tube as an alternative to the commercial insert tube, the volume of the elution solvent was reduced by four-fifths. Even though smaller fractions of the analytes were eluted from the fiber coatings, the analyte concentrations in the elution solutions were substantially increased by using the custom-made insert tube. Therefore, larger amounts of the analytes could be injected to LC and higher signal-to-noise ratios could be achieved, even at smaller injection volumes. Since the elution in the custom-made insert tube was nonexhaustive, four strategies were developed to figure out the extracted amounts in the fiber coatings. In combination with the sampling-rate calibration method, these strategies were successfully used to determine the concentrations of fluoxetine in living tilapias. This study provides a simple but effect way for improving the analytical sensitivity when coupling SPME with LC.Xu, J., Tang, H., Su, S., Liu, J., Xu, K., Qian, K., Wang, Y., Zhou, Y., Hu, S., Zhang, A., Xiang, J., 2018. A study of the relationships between coal structures and combustion characteristics: The insights from micro-Raman spectroscopy based on 32 kinds of Chinese coals. Applied Energy 212, 46-56. and combustion characteristics of 32 kinds of Chinese coals were studied by Micro-Raman spectroscopy and thermal gravimetric analyzer. Changes in coal structures with coalification were investigated by detailed curve-fitting the Raman spectrum with ten Gaussian bands. The relationships between the Raman spectral parameters and coal combustion characteristics were set up and evaluated. The results indicate that the loss of aromatic substituents or aliphatic structures can be responsible for the decrease of Vdaf for low rank coals (volatiles content in dry ash-free basis (Vdaf)?>?25%), while the rapid growth of aromatic rings along with the increase of cross-linking density of coals mainly occurs under coalification for relative high rank coal (Vdaf?>?25%). Besides, C??O structures in coal increase monotonously with the increase of Vdaf. The condensation of aromatic rings, loss of C??O structures and reduction of “impurity” structures among large aromatic rings all can increase the coal combustion characteristic temperatures. Reasonable correlations between the coal combustion characteristic temperatures: Ti, Tm, Tb and Raman spectral parameters: A(GR+VL+VR)/AD, AGL/ATotal, AS/AD, AD/ATotal have been found respectively, and the relationships are all better than that between Ti, Tm, Tb and Vdaf. Particularly, the Raman spectral parameter AD/ATotal is a combination of above key parameters and related to the coal ignition temperature best with the R-square higher than 0.9. AD/ATotal can act as a good indicator for coal combustion characteristics. This study directly demonstrates that Raman spectroscopy can play a probe not only for coal ranks/structures but also coal combustion characteristics and it can provide a new approach to rapidly predict the coal properties.Xu, L., Abedini, A., Qi, Z., Kim, M., Guerrero, A., Sinton, D., 2018. Pore-scale analysis of steam-solvent coinjection: azeotropic temperature, dilution and asphaltene deposition. Fuel 220 151–158. assisted gravity drainage is the main technologically and economically feasible method for in situ bitumen extraction. However, SAGD is energy intensive with economic and environmental challenges. Steam-solvent coinjection has proposed to improve SAGD performance, where hydrocarbon solvent is simultaneously injected with steam to increase the production rate and lower the steam-oil-ratio. The addition of solvent, however, complicates an already complex multicomponent thermal-chemical process. Microfluidics is well suited to quantify the pore-scale of steam-solvent coinjection with a tight control over experimental parameters. In this study, a high-pressure high-temperature micromodel combined with optical and thermal imaging is used to probe the pore-scale of steam-solvent coinjection process at relevant reservoir conditions. The effects of butane and hexane, as well as two industrial solvents, condensate and naphtha, on the pore-scale mechanisms are quantified and compared. The in situ thermal data is used to profile and analyze the condensation zone behavior and steam-solvent azeotropic temperature for all steam-solvent cases. We find that overall performance depends on the difference between steam-solvent azeotropic temperature and steam saturation temperature, the degree of solvent-bitumen dilution, and the degree of asphaltene precipitation in the condensing zone. In contrast with pure solvents and condensate, naphtha results in the highest recovery due to a higher steam-solvent azeotropic temperature, effective dilution, with minimal asphaltene deposition.Xu, W., Gong, L.-f., Pang, K.-L., Luo, Z.-H., 2018. Fungal diversity in deep-sea sediments of a hydrothermal vent system in the Southwest Indian Ridge. Deep Sea Research Part I: Oceanographic Research Papers 131, 16-26. hydrothermal sediment is known to support remarkably diverse microbial consortia. In deep sea environments, fungal communities remain less studied despite their known taxonomic and functional diversity. High-throughput sequencing methods have augmented our capacity to assess eukaryotic diversity and their functions in microbial ecology. Here we provide the first description of the fungal community diversity found in deep sea sediments collected at the Southwest Indian Ridge (SWIR) using culture-dependent and high-throughput sequencing approaches. A total of 138 fungal isolates were cultured from seven different sediment samples using various nutrient media, and these isolates were identified to 14 fungal taxa, including 11 Ascomycota taxa (7 genera) and 3 Basidiomycota taxa (2 genera) based on internal transcribed spacers (ITS1, ITS2 and 5.8 S) of rDNA. Using illumina HiSeq sequencing, a total of 757,467 fungal ITS2 tags were recovered from the samples and clustered into 723 operational taxonomic units (OTUs) belonging to 79 taxa (Ascomycota and Basidiomycota contributed to 99% of all samples) based on 97% sequence similarity. Results from both approaches suggest that there is a high fungal diversity in the deep-sea sediments collected in the SWIR and fungal communities were shown to be slightly different by location, although all were collected from adjacent sites at the SWIR. This study provides baseline data of the fungal diversity and biogeography, and a glimpse to the microbial ecology associated with the deep-sea sediments of the hydrothermal vent system of the Southwest Indian Ridge.Xue, J., Huang, C., Zhang, Y., Liu, Y., Gamal El-Din, M., 2018. Bioreactors for oil sands process-affected water (OSPW) treatment: A critical review. Science of The Total Environment 627, 916-933. has the world's largest oil sands reservoirs. Surface mining and subsequent caustic hot water extraction of bitumen lead to an enormous quantity of tailings (volumetric ratio bitumen:water = 9:1). Due to the zero-discharge approach and the persistency of the complex matrix, oil producers are storing oil sands tailings in vast ponds in Northern Alberta. Oil sands tailings are comprised of sand, clay and process-affected water (OSPW). OSPW contains an extremely complex matrix of organic contaminants (e.g., naphthenic acids (NAs), residual bitumen, and polycyclic aromatic hydrocarbons (PAHs)), which has proven to be toxic to a variety of aquatic species. Biodegradation, among a variety of examined methods, is believed to be one of the most cost effective and practical to treat OSPW. A number of studies have been published on the removal of oil sands related contaminants using biodegradation-based practices. This review focuses on the treatment of OSPW using various bioreactors, comparing bioreactor configurations, operating conditions, performance evaluation and microbial community dynamics. Effort is made to identify the governing biotic and abiotic factors in engineered biological systems receiving OSPW. Generally, biofilms and elevated suspended biomass are beneficial to the resilience and degradation performance of a bioreactor. The review therefore suggests that a hybridization of biofilms and membrane technology (to ensure higher suspended microbial biomass) is a more promising option to remove OSPW organic constituents.Yan, D., Wong, Y.F., Tedone, L., Shellie, R.A., Marriott, P.J., Whittock, S.P., Koutoulis, A., 2018. Chemotyping of new hop (Humulus lupulus L.) genotypes using comprehensive two-dimensional gas chromatography with quadrupole accurate mass time-of-flight mass spectrometry. Journal of Chromatography A 1536, 110-121. two-dimensional gas chromatography with quadrupole accurate mass time-of-flight mass spectrometry (GC × GC-Q-TOFMS) is employed to profile Humulus lupulus L. (hop) essential oils. Comparison of characterised essential oils allows discrimination among chemotypes. Experimental and commercial hop genotypes displayed distinguishable chemotypic patterns among the volatile secondary metabolites making up their essential oils. In total, 210–306 unique compounds were detected (depending on specific genotype), with 99 of these compounds either positively or tentatively identified. Identified volatile secondary metabolites were grouped into esters, monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, oxygenated sesquiterpenes and ketones. Terpenoids were the dominant chemical families across all hop genotypes analysed, representing between 67% and 90% of the total ion count. The multidimensional chromatographic profiles of hop essential oils are extremely information-rich, making GC × GC-Q-TOFMS useful for fast screening of new hybrid hop genotypes, and therefore informing breeding strategies to derive new commercial hop cultivars for the development of distinctive and desirable beers.Yan, Y.-W., Jiang, Q.-Y., Wang, J.-G., Zhu, T., Zou, B., Qiu, Q.-F., Quan, Z.-X., 2018. Microbial communities and diversities in mudflat sediments analyzed using a modified metatranscriptomic method. Frontiers in Microbiology 9, 93. doi: 10.3389/fmicb.2018.00093. mudflats are land–sea interaction areas and play important roles in global nutrient cycles. However, a comprehensive understanding of microbial communities in these mudflats remains elusive. In this study, mudflat sediment samples from the Dongtan wetland of Chongming Island, the largest alluvial island in the world, were collected. Using a modified metatranscriptomic method, the depth-wise distributions of potentially active microbial communities were investigated based on small subunit ribosomal RNA (SSU rRNA) sequences. Multiple environmental factors were also measured and analyzed in conjunction with the prokaryotic composition profiles. A prokaryotic diversity analysis based on the metatranscriptome datasets revealed two or threefold higher diversity indices (associated with potentially active microbes participating in biogeochemical processes in Dongtan) compared with the diversity indices based on 16S rRNA gene amplicons. Bacteria were numerically dominant relative to archaea, and the potentially active prokaryotic taxa were mostly assigned to the bacterial phyla Chloroflexi, Acidobacteria, and Bacteroidetes and the classes Delta- and Gamma-proteobacteria, along with the archaeal lineages phylum Bathyarchaeota and the order Thermoplasmatales. The total nitrogen and carbon content of the sediment samples were environmental factors that significantly affected the depth-wise distributions of both bacterial and archaeal communities. Furthermore, the activity of potentially active taxa (including the prevalent order Desulfobacterales and family Anaerolineaceae) appeared to be significantly underestimated by PCR-based methods, notably at the DNA level, and indicates that using normal PCR amplification of DNA limits the study of potential microbial activity. This is the first study of potentially active microbial communities in depth-wise sediments from Dongtan. The improved knowledge of microbial communities in Dongtan provides a foundation for exploring biogeochemical cycling and microbial functions.Yanez, A.J., Natarajan, P., Li, W., Mabon, R., Broadbelt, L.J., 2018. Coupled structural and kinetic model of lignin fast pyrolysis. Energy & Fuels 32, 1822-1830. biomass is a promising feedstock for renewable fuels and chemical intermediates; in particular, lignin attracts attention for its favorable chemical composition. One obstacle to lignin utilization and valorization is the unknown chemical mechanism that gives rise to the complex product distributions observed upon deconstruction. Among possible deconstruction chemistries, fast pyrolysis is promising due to its short residence time, thus enabling high-volume production. However, the chemistry is inherently complex, thereby hampering the creation of detailed kinetic models describing pathways to specific low molecular products. To this end, we created a detailed kinetic model of lignin decomposition via pyrolysis comprised of 4313 reactions and 1615 species based on pathways suggested by pyrolysis of model compounds in the literature. Using a rule-based reaction network generation approach, a pathways-level reaction network is proposed to predict the evolution of macromolecular species and the formation of various low molecular weight products identified from experimental studies. This reaction network is coupled to a structural model of wheat straw lignin via a kinetic Monte Carlo framework to simulate lignin fast pyrolysis. The mass yields of and speciation within four commonly observed fractions, viz., light gases, an aqueous phase containing water and small oxygenates, char, and a highly complex aromatic fraction, are compared to an experimental report of a putatively similar biomass source. Additional capabilities of the model include the time-resolved prediction of volatilization profiles and the evolution of the molecular weight distribution, which may assist in efforts to valorize lignin to a higher degree than that achieved by current approaches.Yang, C., Hou, L., Yang, F., Luo, X., Wang, J., 2017. Controlling factors of volcanic hydrocarbon reservoirs in Bohai Bay Basin, China. Journal of Natural Gas Geoscience 2, 219-228. hydrocarbon reservoirs are developed in the Mesozoic and Cenozoic strata in Bohai Bay Basin in China. There is more than one hundred million tons of proven oil reserves in the said reservoir. They performed different actors for oil and gas accumulation in the basin. Faults controlled the distribution and accumulation of oil and gas related to volcanic rocks in Bohai Bay Basin. Not to mention, the zone near the faults is favorable for the development of good reservoirs. Volcanic rocks and volcanism can serve several roles during the course of hydrocarbon generation and accumulation. Volcanism can promote hydrocarbon generation from source rocks. Simultaneously, volcanic activity can damage petroleum reservoirs. Volcanic rocks can be both the reservoirs and the cap-rocks or obscured layer in the basin. The occurrence of volcanic rocks in source rocks can form fractures more easily compared to that in sandstones. Finally, volcanic rocks also control the distribution of mantle-derived CO2 gas reservoirs in the basin.Yang, C., Ni, Z., Li, M., Wang, T., Chen, Z., Hong, H., Tian, X., 2018. Pyrobitumen in South China: Organic petrology, chemical composition and geological significance. International Journal of Coal Geology 188, 51-63. has been discovered in the dolostone reservoir of the Central Sichuan Basin, southwest China, accumulates coevally with hydrothermal minerals in pores. The pyrobitumen has strong anisotropy with an evolutionary sequence from mosaic to a fibrous texture. A similar sequence of anisotropy has also been observed in mesophase pitch during the process of coking coal. Reflectance of the pyrobitumen shows a positive correlation with anisotropic evolution and increasing depth. Hopane and sterane biomarkers are abundant in extracts of highly anisotropic pyrobitumen with smooth, rough, hyperplastic surface and honeycomb micropores. Methylpyrene and methylchrysene maturity indicators and the reflectance values of pyrobitumen show a positive linear correlation in Cambrian samples, but show random correlation in Sinian samples. Fluid inclusion microthermometry of hydrothermal minerals, together with the burial and heat flow history of the reservoir indicate an abrupt thermal event that may have impacted the generation and evolution of pyrobitumen. This appears to be confirmed by the reflectance values of pyrobitumen in the source rock and reservoir. The pyrobitumen in source rock was less heated by the hydrothermal fluid due to its poor porosity and have lower reflectance values. However, the pyrobitumen in weathering crust reservoir was more heated by the hydrothermal fluid and have higher reflectance values, because the reservoir rocks have higher porosity. The occurrence and characteristics of pyrobitumen indicate an in-situ pyrolysis of oil, which was triggered by an abrupt thermal event in the reservoir. The reconstruction of burial history and heat flow, as well as the hydrothermal fluid minerals of the dolomite reservoir all indicate the thermal event of the Sichuan Basin might correlate with the Emei mantle plume in Late Permian.Yang, G., Peng, Y., Olefeldt, D., Chen, Y., Wang, G., Li, F., Zhang, D., Wang, J., Yu, J., Liu, L., Qin, S., Sun, T., Yang, Y., 2018. Changes in methane flux along a permafrost thaw sequence on the Tibetan Plateau. Environmental Science & Technology 52, 1244-1252. thaw alters the physical and environmental conditions of soil and may thus cause a positive feedback to climate warming through increased methane emissions. However, the current knowledge of methane emissions following thermokarst development is primarily based on expanding lakes and wetlands, with upland thermokarst being studied less often. In this study, we monitored the methane emissions during the peak growing seasons of two consecutive years along a thaw sequence within a thermo-erosion gully in a Tibetan swamp meadow. Both years had consistent results, with the early and midthaw stages (3 to 12 years since thaw) exhibiting low methane emissions that were similar to those in the undisturbed meadow, while the emissions from the late thaw stage (20 years since thaw) were 3.5 times higher. Our results also showed that the soil water-filled pore space, rather than the soil moisture per se, in combination with the sand content, were the main factors that caused increased methane emissions. These findings differ from the traditional view that upland thermokarst could reduce methane emissions owing to the improvement of drainage conditions, suggesting that upland thermokarst development does not always result in a decrease in methane emissions.Yang, I.H., Lee, H.S., 2018. Desorbed gas volume estimation using conventional well-log data for the Montney Formation, Deep Basin, Canada. Journal of Petroleum Science and Engineering 162, 633-651. study focuses on desorbed gas volume estimation of the Montney Formation, Deep Basin, Canada. Because desorbed gas has significantly contributed to shale gas production, and ranges from 10% to 40% of the total production, an accurate desorbed gas volume estimation is important to evaluate and develop shale gas fields. The desorbed gas volume was calculated using two methods – the adsorption capacity (cf. Langmuir test) and canister volume measurements. Both methods were originally adopted from coal-bed-methane production and applied to shale gas reservoirs after the commercial production of shale gas. The Montney Formation contains less than 2% of total organic carbon, with an average of 0.7% primarily derived from the secondary cracking of migrated oil. This suggests the absence of the adsorption capacity and organoporosity of organic matter. Conversely, the Montney Formation contains more than 20% of clay minerals, and the canister volume test shows that the formation has 22 scf/ton of desorbed gas volume. Based on a mineralogical analysis, this desorbed gas is primarily adsorbed to clay minerals, such as illite, mica, smectite, kaolinite, among others. Because illite is the major component among the clay minerals and has a positive correlation to the canister volume, the illite volume was calculated from conventional well logs to estimate exact desorbed gas volume. We assumed that the clay volume primarily consisted simply of illite and the rest clay minerals and figure out the volume of illite by using neutron-density cross plot.The calculated illite volume has a positive correlation to the canister volume, which can be used to infer the desorbed gas volume of the Montney Formation. The estimated desorbed gas volume in the Montney Formation ranges from 19 to 30 scf/ton, which is lower than the free-gas volume.Yang, J., Li, G., Qian, Y., Yang, Y., Zhang, F., 2018. Microbial functional gene patterns related to soil greenhouse gas emissions in oil contaminated areas. Science of The Total Environment 628–629, 94-102. microbial community structure to physiology and ecological processes is a critical focus of microbial ecology. To understand the microbial functional gene patterns related to soil greenhouse gas [carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O)] emissions under oil contamination, we used functional gene array (GeoChip 5.0) analysis and network methods to investigate the feedback responses of soil microbial functional gene patterns and identify keystone genes in Shengli Oilfield, China. The microbial functional gene number, relative abundance and diversity involved in carbon degradation and nitrogen cycling decreased consistently with the reduced CO2 and N2O flux in oil contaminated soils, whereas the gene number and relative abundance of methane-production related genes increased with contamination. Functional molecular ecological networks were built based on random matrix theory, where network structures and properties showed significantly variation between oil contaminated and uncontaminated soils (P < 0.05). Network nodes, connectivity and complexity all reduced under oil contamination. The sensitive and the highest connective genes in the network were identified as keystone genes, based on Mann-Whitney U tests and network analysis. Our findings improved the understanding of the microbe-mediated mechanisms affecting soil greenhouse gas emissions.Yang, J., Ortega-Hernández, J., Legg, D.A., Lan, T., Hou, J.-b., Zhang, X.-g., 2018. Early Cambrian fuxianhuiids from China reveal origin of the gnathobasic protopodite in euarthropods. Nature Communications 9, Article 470. owe their evolutionary and ecological success to the morphological plasticity of their appendages. Although this variability is partly expressed in the specialization of the protopodite for a feeding function in the post-deutocerebral limbs, the origin of the former structure among Cambrian representatives remains uncertain. Here, we describe Alacaris mirabilis gen. et sp. nov. from the early Cambrian Xiaoshiba Lagerst?tte in China, which reveals the proximal organization of fuxianhuiid appendages in exceptional detail. Proximally, the post-deutocerebral limbs possess an antero-posteriorly compressed protopodite with robust spines. The protopodite is attached to an endopod with more than a dozen podomeres, and an oval flap-shaped exopod. The gnathal edges of the protopodites form an axial food groove along the ventral side of the body, indicating a predatory/scavenging autecology. A cladistic analysis indicates that the fuxianhuiid protopodite represents the phylogenetically earliest occurrence of substantial proximal differentiation within stem-group Euarthropoda illuminating the origin of gnathobasic feeding.Yang, S., Chen, G., Lv, C., Li, C., Yin, N., Yang, F., Xue, L., 2018. Evolution of nanopore structure in lacustrine organic-rich shales during thermal maturation from hydrous pyrolysis, Minhe Basin, Northwest China. Energy Exploration & Exploitation 36, 265-281. nanometer-scaled pore systems of gas shale reservoirs have a prominent contribution for gas storage. To obtain information about the characteristics of the nanopore structure within lacustrine organic-rich shales during their thermal evolution, artificial shale samples with different thermal maturities were obtained from a hydrous pyrolysis experiment. Nitrogen adsorption, field emission scanning electron microscopy, and porosity tests were used to investigate the characteristic pore structures of lacustrine shales with different thermal maturities from the Minhe Basin. The results show that the total organic carbon content decreased from 41.89% (unheated) to 27.7% (370℃) and that organic pores, intragranular pores of pyrite, and intergranular pores of clay minerals began to form with an increase in the simulated temperature and pressure. The porosity increased from 3.57% (unheated) to 26.09% (350℃) and then decreased to 20% (370℃) on the whole. The pore sizes were distributed from 1.7 to 500?nm, and the average pore diameter first showed a decreasing trend and then an increasing trend. The cumulative pore volume and cumulative specific surface area both presented a slowly increasing trend from an unheated status to 325℃, exhibited a rapid increase at 350℃, and then showed a slow increase at 370℃. This study could provide a reference for the exploration of shale gas in lacustrine shales with different thermal maturities.Yang, X., Zhang, Z., Santosh, M., Duan, S., Liang, T., 2018. Anoxic to suboxic Mesoproterozoic ocean: Evidence from iron isotope and geochemistry of siderite in the Banded Iron Formations from North Qilian, NW China. Precambrian Research 307, 115-124. Iron Formations (BIFs) provide important constraints on geochemical cycling of Fe and ancient marine environment. Globally, the formation of BIFs peaked during late Archean and early Paleoproterozoic, with limited reappearance during Neoproterozoic. Here we investigate a rare example of Mesoproterozoic (ca. 1.3?Ga) BIFs from Jingtieshan in the North Qilian region of NW China. We present rare earth element and yttrium (REE?+?Y) compositions together with iron isotope features of siderite from the BIFs, and integrate these with our published data on carbon isotope compositions from the siderite-rich BIFs (including carbonate facies BIFs and mixed carbonate-oxide facies BIFs). Siderite from the BIFs shows REE?+?Y characteristics that are consistent with submarine hydrothermal fluids mixed with seawater, including positive Eu/Eu? anomalies and high Y/Ho ratios. The siderite also displays homogeneous iron isotope compositions (δ56Fe range from ?0.71‰ to ?0.41‰, one sample down to ?1.62‰) and moderate negative carbon isotope compositions (δ13C values?=??8.40‰ to ?3.0‰). These findings argue against the traditional view that siderite associated with BIFs was formed through microbial dissimilatory iron reduction (DIR). Instead, siderite from Jingtieshan BIFs is in equilibrium with submarine hydrothermal fluids and seawater suggesting an inorganic origin, and was directly precipitated from the CO2 and Fe oversaturated water column, with only insignificant role for DIR. These Mesoproterozoic BIFs are also characterized by Ce anomalies, and the siderite falls within the pe–log [S]T and (PO2)–(PCO2) stability fields, suggesting that the BIFs were deposited in an anoxic to suboxic ocean. The results from our study suggest the presence of iron-rich Mesoproterozoic deep ocean in the North Qilian area.Yin, J., Wang, Q., Hao, F., Guo, L., Zou, H., 2018. Palaeoenvironmental reconstruction of lacustrine source rocks in the lower 1st Member of the Shahejie Formation in the Raoyang Sag and the Baxian Sag, Bohai Bay Basin, eastern China. Palaeogeography, Palaeoclimatology, Palaeoecology 495, 87-104. lower 1st Member (Es1L) of the Oligocene Shahejie Formation is the most important source rock interval in the Raoyang Sag and the Baxian Sag. To reveal the controlling factors that affected the distribution of organic-rich source rocks, we analyzed the lower Es1 (Es1L) samples collected from the Raoyang Sag and the Baxian Sag using sedimentological and geochemical techniques to reconstruct the lacustrine palaeoenvironmental conditions. Most of the samples had chemical index of alteration (CIA?) values between 70 and 75, which reflect a stable and moderately weathered source under a transitional climate. The distribution of depocenters and palaeo-water depths indicated that the main catchment area was concentrated in the Raoyang Sag, with a maximum palaeo-water depth of 14 m and a wave-base depth of 7.5 m. Stable isotope data from carbonates (δ18Ocarb and δ13Ccarb) showed that the lakes with long residence times in the Raoyang Sag had a positive correlation and that the lakes with short residence times in the Baxian Sag had no isotopic covariance during the deposition of the lower Es1. The P/Al and P/Ti ratios, Ptotal and carbon isotope values of the organic matter (δ13Corg) in the two sags illustrated stable palaeoproductivity without much fluctuation. The enrichments of Mo, U and ratios of (C:P)org, B/Ga and Sr/Ba further indicated saline and anoxic bottom water conditions associated with stable water-column stratification in Well Xi63 and brackish and less anoxic bottom water conditions in Well ND1 during the deposition of the main source rock of the lower Es1. Moreover, the plots of Mo and U enrichment versus TOC and hydrogen index values versus Δδ13C (i.e., the difference between the δ13C values of carbonates and organic matter) corroborated the inference that the preservation of organic matter was the main factor controlling the formation of organic-rich source rocks in the Raoyang Sag and the Baxian Sag during the deposition of the lower Es1.Yoon, S.H., Joe, Y.J., Koh, C.S., Woo, J.H., Lee, H.S., 2018. Sedimentary processes and depositional environments of the gas-bearing Horn River shale in British Columbia, Canada. Geosciences Journal 22, 33-46. Horn River Basin in the northeastern British Columbia, Canada, is one of the largest unconventional gas-bearing basins in North America. The main reservoir of this gas accumulation is the Devonian Horn River Formation that is stratigraphically divided into three members, the Evie, Otterpark and Muskwa in ascending order. This study focuses on sedimentary processes and depositional environments of the Horn River Formation based on sedimentary facies analysis by the aid of well-log mineralogy (ECS) and total organic carbon (TOC) data from the Kiwigana well. The shales of the formation consist dominantly of silicate minerals (quartz, feldspar and mica) and subordinate clay mineral and carbonate materials, with TOC ranging from 0.3 to 7.6%. Three sedimentary facies were identified on the basis of centimeter-scale description of sedimentary structures and texture in borehole cores: homogeneous mudstone (HM), indistinctly laminated mudstone (ILM), and planar laminated mudstone (PLM). Integration of sedimentary facies, lithology and TOC suggests that the Horn River shale was primarily deposited in overall distal marine setting deeper than shelf or marginal slope, possibly base-of-slope to deeper basin plain off the carbonate reef (or shelf). Facies HM is siliceous and organic-rich, and dominant in the Evie and the overlying lowermost Otterpark members. It is interpreted as a pelagic to hemipelagic deposit formed mainly by suspension fall-out in an anoxic setting below maximum storm wave base. Likewise, facies ILM shows relatively high proportion of silicate minerals and TOC. This facies is identified frequently in the Muskwa and rarely in the Otterpark; it reflects a deposition from hemipelagic settling with an influence of persistent and weak bottom currents or nepheloid flows. Facies PLM, dominant in the large part of the Otterpark, is relatively depleted in silicate minerals and TOC. This facies indicates more frequent inflow of episodic turbidity currents punctuating the hemipelagic settling of the background sedimentation process. During the deposition of the Horn River Formation, the depositional site has experienced an earlier relative sea-level fall changing from a deep basin (Evie) to shallower marginal slope (middle Otterpark), and subsequent relative sea-level rise turning back to a deeper marine environment (Muskwa).You, X.L., Sun, S., Lin, C.S., Zhu, J.Q., 2018. Microbial dolomite in the sabkha environment of the middle Cambrian in the Tarim Basin, NW China. Australian Journal of Earth Sciences 65, 109-120. the Tarim Basin, dolomite, which formed during the middle Cambrian associated with evaporites, has been attributed to the sabkha-style dolomite formed during the syndepositional period. The sedimentary microfacies suggests dolomite formation in the middle Cambrian is an ancient analogue of the sabkha of Abu Dhabi. Poorly crystallised dolomite spheroids or ovoids within or on the surface of dolomite crystals are a common phenomenon that can be widely observed in different stromatolites in the upper part of the intertidal zone and strongly resemble the morphology in modern sabkha dolomite-producing microbial mats and in microbial culture experiments. These lines of evidence suggest organic substrates for dolomite nucleation. Dolomite formation in the middle Cambrian in the Tarim Basin has been considered a classic analogue for carbonate and evaporate assemblages. The extent of microbial dolomite in ancient sabkha environments is proposed as an alternative model for dolomite formation, in which the mineral properties of organic substrates play a crucial role.Yue, R.P.H., Lee, H.F., 2018. Climate change and plague history in Europe. Science China Earth Sciences 61, 163-177. research that reported the linkage between climate change and plague activity primarily refers to the immediate effect of short-term climatic variation. Yet, decades of discussion about the climate-plague association cannot determine the precise role of climate in shaping plague dynamics. One reason for this discrepancy originates from the narrow selection of spatio-temporal settings for comprehensive analysis of the correlation, leading to a limited consideration of the complexity of possible dynamics. By analyzing a 414-year long record of plague outbreak in pre-industrial Europe and the corresponding climatic data in multi-scale, we find little evidence to support climate-plague correlation in (1) both climatic variations and large-scale climatic phenomena, (2) both country scale and continental scale, (3) annual to inter-annual scale, and (4) both linear and non-linear analytic approaches. The null-result should not be viewed as a general rejection of other recent findings related to climate-plague association; nevertheless, it suggests that a wider consideration of scales, sensitivity checks and consideration of contexts should be included in explaining and predicting plague transmission under contemporary global climate conditions.Zachar, I., Szilágyi, A., Számadó, S., Szathmáry, E., 2018. Farming the mitochondrial ancestor as a model of endosymbiotic establishment by natural selection. Proceedings of the National Academy of Sciences 115, E1504-E1510.: The origin of mitochondria is a challenging and intensely debated issue. Mitochondria are ancestrally present in eukaryotes, and their endosymbiotic inclusion was an extremely important step during the transition from prokaryotes to eukaryotes. However, because of the unknown order of eukaryotic inventions (e.g., cytoskeleton, phagocytosis, and endomembranes), it is unknown whether they led to or followed the acquisition of mitochondria. According to the farming hypothesis, the mitochondrial ancestor was captured by a phagocytotic host, but the advantage was not direct metabolic help provided by the symbiont; rather, it was provisioning captured prey to farmers in poor times, like humans farm pigs. Our analytical and computational models prove that farming could lead to stable endosymbiosis without any further benefit assumed between partners.Abstract: The origin of mitochondria was a major evolutionary transition leading to eukaryotes, and is a hotly debated issue. It is unknown whether mitochondria were acquired early or late, and whether it was captured via phagocytosis or syntrophic integration. We present dynamical models to directly simulate the emergence of mitochondria in an ecoevolutionary context. Our results show that regulated farming of prey bacteria and delayed digestion can facilitate the establishment of stable endosymbiosis if prey-rich and prey-poor periods alternate. Stable endosymbiosis emerges without assuming any initial metabolic benefit provided by the engulfed partner, in a wide range of parameters, despite that during good periods farming is costly. Our approach lends support to the appearance of mitochondria before any metabolic coupling has emerged, but after the evolution of primitive phagocytosis by the urkaryote.Zaffani, M., Jadoul, F., Rigo, M., 2018. A new Rhaetian δ13Corg record: Carbon cycle disturbances, volcanism, End-Triassic mass Extinction (ETE). Earth-Science Reviews 178, 92-104. links between large-scale volcanism, carbon cycle perturbations and the biotic crises at the End-Triassic Extinction event (ETE) are not well understood. The ETE seems to be marked by three carbon isotope excursions (CIEs) likely triggered by different eruptive phases of the Central Atlantic Magmatic Province (CAMP). These three CIEs appear to occur during the late Rhaetian, close to the Triassic/Jurassic boundary (TJB), but the relative timing connecting the volcanism, carbon perturbations and extinctions is still subject to debate resulting from: i) the difficulties in long-distance biostratigraphic correlations of Rhaetian successions due to the step-like extinction pattern characterizing the ETE, and to the lack of globally correlatable key-fossil group(s) across the system boundary; ii) the limit of coverage of available δ13C profiles to the system boundary interval, rather than the entire Rhaetian; iii) the inherent difficulties in correlating CIEs without clear biostratigraphic markers. Here we present a δ13Corg curve from the Lombardy Basin which covers for the first time the entire Rhaetian. Using this chemostratigraphy, we propose two possible correlations (option 1 and option 2) with other late Rhaetian to early Hettangian successions worldwide. These two possible correlations rely on a combination of paleontological (ammonoids, pollens, conodonts), lithostratigraphic and geochemical constraints. Option 2 in particular has important implications for the causality and geochronology of the ETE events by suggesting that the sharp negative peak usually considered to be the “initial” CIE in the Lombardy might represent a carbon perturbation within the negative trend of the “main” CIE. This implies that a reconsideration of the succession of biotic events occurring during this time interval is required.Zamudio, G.S., José, M.V., 2018. Identity elements of tRNA as derived from information analysis. Origins of Life and Evolution of Biospheres 48, 73-81. decipherment of the tRNA’s operational code, known as the identity problem, requires the location of the sites in the tRNA structure that are involved in their correct recognition by the corresponding aminoacyl-tRNA synthetase. In this work, we determine the identity elements of each tRNA isoacceptor by means of the variation of information measure from information theory. We show that all isoacceptors exhibit sites associated with some bases of the anticodon. These sites form clusters that are scattered along the tRNA structure. The clusters determine the identity elements of each tRNA. We derive a catalogue of clustered sites for each tRNA that expands previously reported elements.Zamudio, G.S., José, M.V., 2018. Phenotypic graphs and evolution unfold the Standard Genetic Code as the optimal. Origins of Life and Evolution of Biospheres 48, 83-91. this work, we explicitly consider the evolution of the Standard Genetic Code (SGC) by assuming two evolutionary stages, to wit, the primeval RNY code and two intermediate codes in between. We used network theory and graph theory to measure the connectivity of each phenotypic graph. The connectivity values are compared to the values of the codes under different randomization scenarios. An error-correcting optimal code is one in which the algebraic connectivity is minimized. We show that the SGC is optimal in regard to its robustness and error-tolerance when compared to all random codes under different assumptions.Zelenev, A.S., Grenoble, Z., 2018. Wettability of reservoir rocks having different polarity by a model nonionic surfactant: Fluid imbibition study into crushed rock packs. Energy & Fuels 32, 1340-1347. imbibition of solutions of a model nonionic surfactant into packed beds of crushed reservoir rocks was studied using the Washburn technique. A linear dependence between the equivalent height of capillary rise and the square root of imbibition time was observed at different stages of imbibition experiments. It has been shown that, under the conditions when surfactants did not alter the polarity of rocks, the imbibition rate of surfactant solutions correlated well with the nondispersion (polar) component of the surface free energy of the rocks. It was possible to compare data obtained for different rocks by normalizing the slopes of imbibition curves over the corresponding slopes determined for a completely wetting fluid, hexamethyldisiloxane (HMDS). Such a normalization allowed one to account for substantial differences in the morphology of crushed rock powders. Overall, the observed trends in the imbibition behavior were qualitatively similar to the trends reported previously for the rise of surfactant solutions in single capillaries. The largest qualitative impact of nonionic surfactant was observed in the imbibition into hydrophobic oily sandstone, in which case a surfactant-induced shift to hydrophilicity was observed. Overall, high concentrations were needed in order to observe the impact of surfactant on the imbibition rate.Zeng, F., Guo, J., Ma, S., Chen, Z., 2018. 3D observations of the hydraulic fracturing process for a model non-cemented horizontal well under true triaxial conditions using an X-ray CT imaging technique. Journal of Natural Gas Science and Engineering 52, 128-140. investigate the spatial evolution of fractures in non-cemented horizontal wells, cubic cement specimens were fractured in triaxial experiments to reproduce hydraulic fracturing in field applications. Systematic experiments were conducted on specimens with different azimuth angles (0°, 30°, 45°, 60° and 90°), horizontal principal stress anisotropies (10?MPa and 4?MPa) and fracturing fluid viscosities (60?mPa·s and 5?mPa·s). All the tests were performed by injecting fluid at a constant rate of 9?cc/min. High-resolution non-destructive 3D X-ray microtomography was used to record the internal evolution of the induced fractures. The X-ray computed tomography (CT) imaging technique can produce complex 3D images of fracture systems with little artificial noise. The complex fracture geometries observed are a result of the rapidly changing stress conditions at the wellbore wall during injection and of the mechanical interaction among the fractures. The magnitudes of the well azimuth angle, principal stress anisotropy and injection fluid viscosity play significant roles in the evolution of the induced fractures. For a high horizontal differential stress of 10?MPa, the fracture morphologies are primarily determined by the in situ stresses, and the fractures extend in the direction of the maximum principal stress. However, when the horizontal differential stress is 4?MPa, the fracture geometry is influenced by the combined effects of the induced stress from the open-hole wellbore, fracture internal pressure distribution, far-field stresses and azimuth angle. In general, an induced fracture is planar at both a low (0°) and high (90°) azimuth angles, while twisted fractures form at intermediate azimuth angles (30°, 45° and 60°). In addition, the injection fluid with a low viscosity of 5?mPa·s easily infiltrates the formation, inducing a fracture network, in contrast to the smooth fracture plane induced by the injection fluid with a high viscosity of 60?mPa·s. Finally, we propose a new parameter, called the dimensionless net pressure, which can reflect the combined effects of the principal horizontal stress difference, well azimuth angle and injection fluid parameters on the evolution of the hydraulic fractures. The complexity of the fracture geometries is strongly and positively correlated with the dimensionless net pressure.Zeng, Q., Wang, Z., Liu, L., Ye, J., McPherson, B.J., McLennan, J.D., 2018. Modeling CH4 displacement by CO2 in deformed coalbeds during enhanced coalbed methane recovery. Energy & Fuels 32, 1942-1955. adsorption and desorption and displacement has a significant effect on coal deformation and permeability evolution during the primary recovery of coalbed methane (CBM) and enhanced coalbed methane recovery (ECBM). The objectives are to (1) quantify the coal deformation and permeability change caused by methane (CH4) displacement with carbon dioxide (CO2) and (2) model the transportation of CH4 and CO2 in deformed coalbed. In this study, the gas adsorption and desorption and displacement, coal deformation, and permeability evolution during CBM and ECBM recovery were described by an internally consistent adsorption-strain-permeability model, of which the simplified local density (SLD) adsorption theory, a theoretical strain model, and a matchstick-based permeability model were rigorous coupled. The coupled model was then verified with all of the CH4 and CO2 measured gas adsorption and desorption and coal strain data published in the past 60 years. Next, sensitivity analysis was further conducted on the coupled model to highlight and calibrate its performance. Finally, the coupled model was integrated into the Transport of Unsaturated Groundwater and Heat Simulator (TOUGH2) to simulate the ECBM process. The results show that the coupled model can simultaneously describe gas adsorption and desorption and displacement, coal deformation, and permeability evolution during ECBM recovery with only six parameters, including slit width, solid–solid interaction potential energy parameter, surface areas of CH4 and CO2, adsorption expansion modulus, and initial porosity. The coupled model can predict both CH4 and CO2 adsorption and the induced coal deformation fairly accurately at a pressure up to 20 MPa, and the average relative errors are within 9.76% and 9.14%, respectively. The results also suggest that the adsorption capacity of CO2 is 2–5 times as large as that of CH4, and the volumetric strain induced by CO2 adsorption is 2–8 times as large as that caused by CH4 adsorption. While the stronger adsorption capacity of CO2 on coal offers an option for CO2-ECBM, matrix swelling due to CH4 displacement with CO2 may narrow down or even close the cleat, significantly reducing the permeability and thus impacting the injection efficiency. Last but not least, the original TOUGH2 simulator predicts similar results with several other CBM simulators. However, it is impossible that 90% of CH4 can be displaced within 90 days. Considering the coal deformation and permeability change due to CH4 displacement with CO2, the modified TOUGH2 simulator shows that only 24% of CH4 is displaced in the first 90 days, and it takes about 1800 days to displace 90% or more. Advances in the understanding of CH4 displacement by CO2 and their transportation mechanisms in coal seams suggests that the success of CO2-ECBM depends on the optimal management of matrix swelling.Zhan, L., Xie, X., Li, Y., Liu, H., Xiong, C., Nie, Z., 2018. Differentiation and relative quantitation of disaccharide isomers by MALDI-TOF/TOF mass spectrometry. Analytical Chemistry 90, 1525-1530. isomer differentiation has been a challenge in glycomics, as the lack of technology to decipher fully the diverse structures of compositions, linkages, and anomeric configurations. Several mass spectrometry-based methods have been applied to the discrimination of disaccharide isomers, but limited quantitative analyses have been reported. In the present study, MALDI-LIFT-TOF/TOF has been investigated to differentiate and relatively quantify underivatized glucose-containing disaccharide isomers that differ in composition, connectivity or configuration. N-(1-naphthyl)ethylenediamine dihydrochloride (NEDC) was used as a highly sensitive matrix without matrix interferences in low mass range, thus yielding intense chloride-attached disaccharide ions [M + Cl]?, which could be fragmented to give diagnostic characteristic fragment patterns for distinguishing these isomers. Three different types of disaccharide isomers were successfully relatively quantified in a binary mixture using the specific product ion pairs. Finally, this method was utilized to identify and relatively quantify two disaccharide isomers in Medicago leaf (maltose and sucrose) without numerous preparation steps. In general, this method is a fast, effective, and robust method for rapid differentiation and quantitation of disaccharide isomers in complex medium.Zhang, D., Feng, Z., Yang, Y., Lan, B., Ran, M., Mu, G., 2018. Peat δ13Ccelluose-recorded wetting trend during the past 8000?years in the southern Altai Mountains, northern Xinjiang, NW China. Journal of Asian Earth Sciences 156, 174-179. have been large discrepancies in the proposed mechanisms accounting for the wetting trend since ～8.0?cal. kyr BP in the Altai Mountains and the surrounding areas. To validate or invalidate the widely reported wetting trend, we obtained a carbon isotope of cellulose (δ13Ccelluose)-recorded warm-season moisture history from a Narenxia (NRX) peat core in the southern Altai Mountains, northern Xinjiang, NW China. The δ13Ccelluose-recorded warm-season moisture reconstruction of the NRX peat core provides a strong support to the widely-reported proposition that the climate was generally dry before ～8.0?cal. kyr BP and was changed to a wetting trend during the past ～8000?years in the Altai Mountains and the surrounding areas. The wetting trend since ～8.0?cal. kyr BP well resembles the increasing trend of the reconnaissance drought index (RDI) that was calculated on the basis of pollen-inferred temperature and precipitation data from the same core. The resemblance implies that the wetting trend during the past ～8000?years resulted from the combined effect of temperature and precipitation.Zhang, H., Yang, M., 2018. Characterization of brominated disinfection byproducts formed during chloramination of fulvic acid in the presence of bromide. Science of The Total Environment 627, 118-124. date, study on the speciation of brominated disinfection byproducts (Br-DBPs), which have higher cytotoxicity and genotoxicity than their analogous chlorinated DBPs (Cl-DBPs), formed in chloramination is still limited. In this study, the previous unknown Br-DBPs formed during chloramination of artificial drinking water were explored with electrospray ionization ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). In total, 193 formulae of one bromine containing Br-DBPs and 5 formulae of two bromine containing Br-DBPs were detected in the chloraminated artificial drinking water sample. Compared to Br-DBPs formed in chlorination, Br-DBPs formed in chloramination have relatively high O/C ratio for the same nominal molecular mass. More than 63% of the Br-DBPs formed during chloramination can be classified as aromatic molecules or polycyclic aromatic molecules, according to their modified aromaticity index (AImod). Further investigation on the change of precursor SRFA molecules during chloramination showed that SRFA molecules with high O/C ratio and low H/C ratio were more reactive and decreased significantly in relative abundance during chloramination. Precursor SRFA molecules with high degree of oxidation and high unsaturation were preferred to form Br-DBPs during chloramination. The results reported in this study provide valuable information on Br-DBPs formed during chloramination and may help us in minimizing DBPs during chloramination.Zhang, K., Guo, Y., Bai, G., Wang, Z., Fan, B., Wu, J., Niu, X., 2018. Pore-structure characterization of the Eocene Sha-3 sandstones in the Bohai Bay Basin, China. Energy & Fuels 32, 1579-1591. intrusion capillary pressure (MICP), nuclear magnetic resonance (NMR), routine core analysis, thin sections, and scanning electron microscope (SEM) analysis were used to gain insight into the pore structure of the Eocene Sha-3 (the third member of the Shahejie formation) low-permeability sandstones in the Raoyang sag, including pore type, pore geometry, and pore size. Quantitative NMR parameters and petrophysical properties were integrated to build up the relationship between microscopic pore structure and macroscopic performance. The pore systems of Sha-3 sandstones are dominantly of residual intergranular pores, intragranular dissolution pores, and intercrystallite micropores associated with authigenic clay minerals. The high threshold pressure and low mercury withdrawal efficiencies from MICP analysis indicate the poor pore connectivity and strong heterogeneous. Both uni- and bimodal transverse relaxation time (T2) spectrum can be found because of the coexistence of small and large pores, and the T2 of major pore size occurring at about 1.0 to 100 ms. The Sha-3 sandstones have a relatively high irreducible water content and short T2 components in the T2 range. Long T2 components can only be observed in samples rich in large pores or microfractures. T2gm (the geometric mean of the T2 distribution) correlates well with irreducible water saturation and permeability. A methodology for pore structure classification is presented integrating NMR parameters of T2gm, bulk volume of immovable fluid (BVI), and petrophysical parameters such as reservoir quality index (RQI) and permeability. Consequently, four types of pore structures (types A, B, C, and D) are identified, and characteristics of individual pore structure are summarized. The comprehensive analysis of NMR measurements combined with thin sections, SEM and MICP analysis is useful for describing microscopic pore structure, which is important to maintaining and enhancing petroleum recovery in low-permeability sandstone reservoirs.Zhang, K., Jin, W., Lin, H., Dong, C., Wu, S., 2018. Major and trace elemental compositions of the upper Carboniferous Batamayineishan mudrocks, Wulungu area, Junggar Basin, China: Implications for controls on the formation of the organic-rich source rocks. Marine and Petroleum Geology 91, 550-561. upper Carboniferous Batamayineishan mudstones are an important and effective gas source rock in the Wulungu area. These sediments are rich in organic matter, however, organic matter accumulation has not been studied before in these mudstones. The major and trace elements were used to reconstruct the depositional environments of these sediments and to improve our understanding of the factors controlling organic matter accumulation. Major and trace elements data indicate that: (1) paleoweathering was low to intermediate in the source terrain; (2) paleoclimate was hot and arid during late Carboniferous in the Wulungu area; (3) low paleoproductivity may have been induced by the low input of nutrients caused by the hot arid climate; (4) the Batamayineishan mudstones were deposited under a reducing environment; (5) organic matter accumulation in these studied deposits was mainly controlled by the input of higher plants rather than redox conditions and paleoproductivity.Zhang, L., Chang, S., Khan, M.Z., Feng, Q., Danelian, T., Clausen, S., Tribovillard, N., Steiner, M., 2018. The link between metazoan diversity and paleo-oxygenation in the early Cambrian: An integrated palaeontological and geochemical record from the eastern Three Gorges Region of South China. Palaeogeography, Palaeoclimatology, Palaeoecology 495, 24-41. link between environmental perturbations, especially oceanic redox conditions, and evolution during the “Cambrian Biodiversification” event is still highly controversial, although this issue has attracted considerable attention for decades. We here report on the fossil record of the early Cambrian biota discovered in the uppermost Yanjiahe and Shuijingtuo formations that crop out in the Luojiacun and Qiaojiaping sections, eastern Three Gorges area, South China. The uppermost member of the Yanjiahe Formation contains abundant benthic algae. Based on the fossil record, four distinct intervals were recognized in the Shuijingtuo Formation: i) few sessile suspension feeders, such as sponges, were recovered from Interval I; ii) Interval II is dominated by bivalved arthropods living in the water column; in this interval are also found a few sponges and eodiscoid trilobites, iii) no fossils other than few sponge spicules were recovered from Interval III; iv) diverse benthic communities composed of sponges, cnidarians, brachiopods, as well as bradoriids dominate Interval IV. Comprehensive research on framboidal pyrite morphology, whole rock geochemistry, as well as in-situ LA-ICP-MS analyses were carried out on samples from the Luojiacun section in order to assess paleo-redox conditions. The results show that the overall evolution of the paleo-redox conditions was characterized by a double episode of sharp anoxic events (AE) observed at the base of intervals I and III, followed by a gradual oxygenation event (OE). Evidence of oxygenation fluctuations were detected, especially within Interval IV. A case study is presented herein, which brings together early Cambrian changes in metazoan diversity and changes in environmental conditions. It is suggested that periodical oxygenation of the water column increased the biological diversity in the restricted basins of the eastern Three Gorges. Thus, four intervals of habitat succession can be tentatively reconstructed in the studied area for the Cambrian Age 2–Age 3 interval indicating a transition from uninhabited sediments to well-populated habitats. Finally, both the temporal and spatial characteristics of the Cambrian AEs/OEs and the fossil record in South China are compared and links between them are discussed in the context of their specific paleo-geographical setting.Zhang, L., Wang, C., Wignall, P.B., Kluge, T., Wan, X., Wang, Q., Gao, Y., 2018. Deccan volcanism caused coupled pCO2 and terrestrial temperature rises, and pre-impact extinctions in northern China. Geology 46, 271-274. the terrestrial climate record provides a critical test of the roles of Chicxulub impact and Deccan Traps volcanism during the Cretaceous-Paleogene (K-Pg) mass extinction. Most evidence came from marine records, but our new clumped isotopes data from paleosol carbonates in the Songliao Basin provide a terrestrial climate history from northern China. This reveals there was a pre-impact warming caused by the onset of Deccan Traps volcanism, whereas the following short-term cooling then another warming episode were likely caused by Chicxulub impact and post-boundary volcanism. Our study suggests that the pCO2 levels were probably the main control on the latest Cretaceous cooling and the climatic fluctuations across the K-Pg boundary interval in northern China. In the Songliao Basin, the pre-impact Deccan Traps volcanism links to losses of half of the lacustrine algae species (charophytes) and almost all of the lacustrine ostracodes; this suggests that the Deccan Traps volcanism had already destabilized the ecosystem and caused extinctions prior to the Chicxulub impact.Zhang, L., Zhang, Y., Gamal El-Din, M., 2018. Degradation of recalcitrant naphthenic acids from raw and ozonated oil sands process-affected waters by a semi-passive biofiltration process. Water Research 133, 310-318. this study, a fixed-bed biofiltration system (biofilter) that utilized indigenous microorganisms was developed for the reclamation of oil sands process-affected water (OSPW). With the assistance of quantitative polymerase chain reaction (qPCR) and confocal laser scanning microscopy (CLSM), indigenous microorganisms from OSPW were able to attach to the surface of sand media and form biofilms. The number of total bacteria on the biofilter media reached a steady state (109/g) after 23 days of operation. Ultra Performance Liquid Chromatography/High Resolution Mass Spectrometry (UPLC/HRMS) analysis showed that 21.8% of the classical naphthenic acids (NAs) removal was achieved through the circulation of raw OSPW on the biofilter for 8 times (equivalent to a hydraulic retention time of 16?h). When ozonation with utilized ozone dose of 30?mg/L was applied as pretreatment, the classical NAs in the ozonated OSPW were removed by 89.3% with an accelerated biodegradation rate of 0.5?mg/L/h. Compared with other biofilm reactors such as moving bed biofilm reactor (MBBR), ozonation pretreatment could benefit the biodegradation of NAs in the biofilter more (classical NA removal: 89.3% vs. 34.4%), especially for those with high carbon number and cyclicity. The combined ozonation-biofiltration process could remove 92.7% of classical NAs from raw OSPW in 16?h. Although both ozonation and biofiltration alone did not show degradation of oxidized NAs from raw OSPW, the combined process led to a 52.9% and 42.6% removal for O3-NAs and O4-NAs, respectively, which were the dominant oxidized NA species in OSPW. Metagenomic sequencing analysis showed that Rhodococcus was the dominant bacterial genus on the sand media, which may play a crucial role during the NA biodegradation. With the advantage of high NA removal efficiency, the combined ozonation-biofiltration process is a promising approach for NA degradation and shows high potential to be scaled up for in-situ OSPW treatment.Zhang, M., Fu, X., 2018. Study of the characteristics of marine–terrigenous facies shale from the Permo-Carboniferous system in the Guxian Block, southwest Qinshui Basin. Energy & Fuels 32, 1096-1109. paper analyzes the characteristics of coal measure shale using samples from the Guxian Block of the southwest Qinshui Basin. Several methods, including X-ray diffraction (XRD), Rock-Eval pyrolysis, high-pressure mercury intrusion porosimetry (MIP), low-temperature nitrogen adsorption/desorption, and isothermal adsorption experiments, were used to investigate the organic geochemical characteristics, mineral composition, pore structure, and methane adsorption characteristics of the shales. Furthermore, the effect of the total organic carbon (TOC), thermal maturity, and mineral composition on the pore structure and methane adsorption capacity of shale was also investigated. The results showed that the TOC of the shale samples ranged from 0.19 to 31.66%, and the shale samples with TOC higher than 2% account for 31.17% of the total samples. The shale samples were in the high overmature stage with high hydrocarbon conversion rates. The mineral composition of the shale samples are mainly clay minerals and quartz, and the brittleness index calculated on the basis of mineral component is distributed primarily in the range from 40 to 50%, suggesting that the shale reservoirs have better fracturing properties. The mesopores were the major provider of pore volume, followed by macropores, and the micropores provided the least pore volume. The pores are open in style and mainly consist of cylindrical pores, parallel-plate slit pores, and bottleneck pores. TOC was the main controlling factor for the development of pores, followed by clay minerals. The pore specific volume created by organic matter was far greater than that of the clay minerals. Quartz arrested the development of pores, and the increase in the quartz content reduced the porosity by approximately 0.57–1.42%. As R0 increased, the porosity first increased at the high-maturity stage and then decreased at the overmature stage. The maximum value appeared when R0 = 2.0%. The TOC-normalized methane adsorption capacity decreased as R0 increased. There was no obvious correlation between the clay mineral content and the TOC-normalized methane adsorption capacity, which may be attributed to the shale water content. Vertically, as the sedimentary facies transited from carbonate tidal flat facies to delta facies, the porosity, Brunauer–Emmett–Teller (BET) specific surface area, Barrett–Joyner–Halenda (BJH) pore volume, and Langmuir volume generally decreased and the physical reservoir properties of the shale reservoir became weaker.Zhang, Q., Amor, K., Galer, S.J.G., Thompson, I., Porcelli, D., 2018. Variations of stable isotope fractionation during bacterial chromium reduction processes and their implications. Chemical Geology 481, 155-164. chemical processes generate subtle but readily measured changes in isotope compositions of elements across the periodic table. The elements involved therefore carry diagnostic information about their chemical histories in complex geochemical or biochemical environments. Distinctive Cr isotope signatures can be used to identify immobilization processes of Cr in the environment, such as microbial Cr(VI) reduction, abiotic Cr(VI) reduction, and adsorption. Here we demonstrate that under well-controlled conditions, Cr isotopes can also be used to distinguish between different biological Cr(VI) reduction pathways. The reduction of Cr(VI) by two facultative anaerobic bacteria, Pseudomonas fluorescens LB 300 and Shewanella oneidensis MR 1, was investigated to determine the conditions under which Cr(VI) is reduced and to quantify the corresponding isotope signatures. The present study considers the effects of a broad range of parameters on Cr isotope fractionation, including bacterial species, electron donors, pH, and respiration pathways (aerobic vs. anaerobic) that must be considered for understanding Cr isotope variations under different experimental and environmental conditions.In the bacterial Cr(VI) reduction experiments, the 53Cr/52Cr isotope ratio of the remaining Cr(VI) increased by up to + 8‰, indicating that lighter isotopes of Cr were preferentially reduced. In aerobic experiments, although Cr reduction rates increased as pH increased from 4 to 8, the fractionation factor did not vary significantly (ε?=??3.21 ± 0.18‰). Experiments using different electron donors demonstrated that citrate promoted the greatest Cr reduction rate compared with glucose, acetate, and propionate. Under aerobic conditions, although the Cr(VI) reduction rates varied substantially between different experimental settings, the isotope fractionation factors were indistinguishable between all the environmental conditions examined (ε?=??3.1‰), with the exception of when citrate was the electron donor (ε?=??4.3‰).Cr reduction rates were generally much faster under anaerobic conditions for both bacteria investigated. The utilisation of different electron donors resulted in the same Cr reduction rates by the bacteria, but fractionated Cr with a broad range of isotope fractionation factors, from ? 1.58 ± 0.16‰ to ? 4.93 ± 0.36‰. Although it has been proposed in many previous studies that there is an inverse relationship between reduction rates and the fractionation factors, no clear relationship between the reduction rates and fractionation factors was observed in this study.The Cr isotope fractionation factors ε were insensitive to pH and electron donor concentration, but dependent on the type of electron donors and redox conditions in the cultures. This indicates that isotope variations may be used to identify when different biological pathways are involved, and so to investigate metabolic processes. The ε value from all experimental conditions examined ranged between ? 1.58 and ? 4.93‰, with a mean value at ? 3.3‰. While Cr isotopes might be used to separate the effects of abiotic and microbially mediated reduction in environmental sites, the fractionation factors from reduction by individual bacterial species overlap with those from several individual abiotic reduction processes, suggesting that site-specific data (e.g., fractionation factors associated with indigenous bacterial populations and local groundwater chemistry) are required in order to use Cr isotopes to distinguish between different reduction mechanisms.Zhang, W., Pan, Y., Yang, J., Chen, H., Holohan, B., Vaudrey, J., Lin, S., McManus, G.B., 2018. The diversity and biogeography of abundant and rare intertidal marine microeukaryotes explained by environment and dispersal limitation. Environmental Microbiology 20, 462-476. microeukaryotes are key ecosystem drivers in marine sandy beaches, an important and dynamic environment; however, little is known about their diversity and biogeography on a large spatial scale. Here, we investigated the community composition and geographical distributions of benthic microeukaryotes using high-throughput sequencing of the 18S rRNA gene and quantified the contributions of environmental factors and spatial separation on the distribution patterns of both rare and abundant taxa. We collected 36 intertidal samples at 12 sandy beaches from four regions that spanned distances from 0.001 to 12,000?km. We found 12,890 operational taxonomic units (OTUs; 97% sequence identity level) including members of all eukaryotic super-groups and several phyla of uncertain position. Arthropoda and Diatomeae dominated the sequence reads in abundance, but Ciliophora and Discoba were the most diverse groups across all samples. About one-third of the OTUs could not be definitively classified at a similarity level of 80%, supporting the view that a large number of rare and minute marine species may have escaped previous characterization. We found generally similar geographical patterns for abundant and rare microeukaryotic sub-communities, and both showed a significant distance–decay similarity trend. Variation partitioning showed that both rare and abundant sub-communities exhibited a slightly stronger response to environmental factors than spatial (distance) factors. However, the abundant sub-community was strongly correlated with variations in spatial, environmental and sediment grain size factors (66% of variance explained), but the rare assemblage was not (16%). This suggests that different or more complex mechanisms generate and maintain diversity in the rare biosphere in this habitat.Zhang, Y., Adam, M., Hart, A., Wood, J., Rigby, S.P., Robinson, J.P., 2018. Impact of oil composition on microwave heating behavior of heavy oils. Energy & Fuels 32, 1592-1599. heating techniques have recently received significant attention as alternatives to conventional heating methods for thermal processing of viscous and heavy oils. One of the benefits of electromagnetic heating is that the electromagnetic field can penetrate the viscous oil and the rock matrix, allowing heating to take place a significant distance from the electromagnetic source. Opportunities exist for electromagnetic heating in overcoming the heat-transfer limitations within viscous oils and potentially as a down-hole or in situ heating technique to raise the temperature within a reservoir. The fundamental interaction of electromagnetic energy with viscous and heavy oils and their constituent components is poorly understood, and this study enhances the understanding of these interactions at microwave frequencies by establishing the effect of temperature on the dielectric properties of heavy oil and its SARA fractions. The dielectric properties of two heavy oils were studied at temperatures up to 300 °C and frequencies from 900 MHz to 3.0 GHz. The loss factor of both oils was found to increase significantly with temperature, which was linked to a corresponding reduction in viscosity. It is shown for the first time, contrary to previous assertions in the literature, that aromatics and resins are the main contributors toward dielectric loss in heavy oils, whereas saturates and asphaltenes were found to have a negligible influence on the loss factor of the oil. Thus, it will be seen that, at higher temperatures or where there is a high abundance of aromatics and resins, the oils are more susceptible to being heated directly with microwaves, opening up new opportunities for microwave processing of oils in refinery and field settings without the need for microwave-absorbing additives.Zhang, Y., Bach, L.T., Lohbeck, K.T., Schulz, K.G., Listmann, L., Klapper, R., Riebesell, U., 2018. Population-specific responses in physiological rates of Emiliania huxleyi to a broad CO2 range. Biogeosciences Discussions 2018, 1-35. coccolithophore physiological responses to CO2-induced changes in seawater carbonate chemistry have been widely studied in the past, there is limited knowledge on the variability of physiological responses between populations. In the present study, we investigated the population-specific responses of growth, particulate organic (POC) and inorganic carbon (PIC) production rates of 17 strains of the coccolithophore Emiliania huxleyi from three regions in the North Atlantic Ocean (Azores, Canary Islands, and Norwegian coast near Bergen) to a CO2 partial pressure (pCO2) range from 120??atm to 2630??atm. Physiological rates of each population and individual strain displayed the expected optimum curve responses to the pCO2 gradient. Optimal pCO2 for growth and POC production rates and tolerance to low pH (i.e. high proton concentration) was significantly higher in an E. huxleyi population isolated from a Norwegian fjord than in those isolated near the Azores and Canary Islands. This may be due to the large pCO2 and pH variability in coastal waters off Bergen compared to the rather stable oceanic conditions at the other two sites. Maximum growth and POC production rates of the Azores and Bergen populations were similar and significantly higher than of the Canary Islands population. One of the reasons may be that the chosen incubation temperature (16?°C) is slightly below what strains isolated near the Canary Islands normally experience. Our results indicate adaptation of E. huxleyi to their local environmental conditions. Within each population, different growth, POC and PIC production rates at different pCO2 levels indicated strain-specific phenotypic plasticity. The existence of distinct carbonate chemistry responses between and within populations will likely benefit E. huxleyi to acclimate to rising CO2 levels in the oceans.Zhang, Y., Wen, H., Zhu, C., Fan, H., Cloquet, C., 2018. Cadmium isotopic evidence for the evolution of marine primary productivity and the biological extinction event during the Permian-Triassic crisis from the Meishan section, South China. Chemical Geology 481, 110-118. (Cd) isotopic compositions in seawater are important parameters for tracing the biogeochemical cycling of Cd in modern oceans and may be used as a direct proxy for nutrient utilization by phytoplankton and an indirect proxy for primary productivity. In this study, we measured the stable Cd isotope ratios (δ114Cd) of marine sedimentary carbonates from the Meishan section in Changxing County of Zhejiang Province, South China, the Global Stratotype Section and Point (GSSP) of the Permian-Triassic Boundary (PTB). The results suggest that the inferred marine primary productivity recorded in the marine carbonates from the Late Permian (i.e., before the mass extinction) was high and relatively stable (the δ114/110Cd values of carbonates range from +0.31‰ to +0.60‰; after correction for salinity-controlled fractionation into inorganic calcite, the δ114/110Cd values of palaeo-seawater range from +0.47‰ to +0.79‰). During the mass extinctions, the δ114/110Cd values of carbonates abruptly decreased at the beginning of each episode of mass extinction, suggesting that the primary productivity of the palaeo-ocean declined before each episode of extinction events at the PTB. We suggest that the mass extinction events at the PTB in the Meishan section could be a ripple effect due to the destruction of primary producers at the base of the food chain in the palaeo-ocean ecosystem.Zhao, B., Hu, Q., Guo, X., Liao, Z., Sarmiento, F., Mesbah, N.M., Yan, Y., Li, J., Wiegel, J., 2018. Natronolimnobius aegyptiacus sp. nov., an extremely halophilic alkalithermophilic archaeon isolated from the athalassohaline Wadi An Natrun, Egypt. International Journal of Systematic and Evolutionary Microbiology 68, 498-506. obligately aerobic extremely halophilic alkalithermophilic archaeon, strain JW/NM-HA 15T, was isolated from the sediments of Wadi An Natrun in Egypt. Phylogenetic analysis based on 16S rRNA and rpoB′ gene sequences indicated that it belongs to the family Natrialbaceae of the order Natrialbales . The closest relatives were Natronolimnobius baerhuensis IHC-005T and Natronolimnobius innermongolicus N-1311T (95.3 and 94.5?% 16S rRNA gene sequence similarity, respectively). Genome relatedness between strain JW/NM-HA 15T and its neighbours was evaluated using average nucleotide identity, digital DNA–DNA hybridization and average amino acid identity with the values of 75.7–85.0, 18.1–20.0, and 70.2–71.0%, respectively. Cells were obligately aerobic, rod-shaped, non-motile, Gram-stain-negative and chemo-organotrophic. The strain grew in the presence of 2.57?M to saturating Na+ (optimum 3.25–4.60 M Na+), at pH55?°C 7.5–10.5 (optimum pH55?°C 9.0–9.5), and at 30–56?°C (optimum 52?°C). The major polar lipids consisted of phosphatidylglycerol, methylated phosphatidylglycerolphosphate and two phospholipids. The complete genome size of strain JW/NM-HA 15T is approximately 3.93?Mb, with a DNA G+C?content of 64.1?mol%. On the basis of phylogenetic features, genomic relatedness, phenotypic and chemotaxonomic data, strain JW/NM-HA 15T was thus considered to represent a novel species within the genus Natronolimnobius , for which the name Natronolimnobius aegyptiacus sp. nov. is proposed. The type strain is JW/NM-HA 15T (=ATCC BAA-2088T =DSM 23470T). The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene and the ropB' gene sequences of strain JW/NM-HA 15T, and the whole complete genome sequence draft genome assembly of Natronolimnobius baerhuensis strain CGMCC 1.3597T are KX857214, CP019893 and MWPH00000000, respectively.Zhao, G., Sheng, Y., Wang, C., Yang, J., Wang, Q., Chen, L., 2018. In situ microbial remediation of crude oil-soaked marine sediments using zeolite carrier with a polymer coating. Marine Pollution Bulletin 129, 172-178. oil spill pollution is an important environmental problem in the world, especially crude oil-soaked marine sediments, because they are difficult to be remediated. In this study, in situ bioremediation of oil-soaked sediment was performed in the middle of the Bohai Sea. Oil-degrading bacteria were adsorbed on powdery zeolite (PZ)/granular zeolites (GZ) surfaces and then wrapped with poly-γ glutamic acid (γ-PGA). Settling column and wave flume experiments were conducted to model marine conditions and to select appropriate biological reagents. The optimal conditions were as follows: the average diameter of GZ 3?mm, mass ratio of GZ/PZ 2:1, and concentration of γ-PGA 7%. After bioremediation, over 50% of most oil-spilled pollutants n-alkanes (C12 to C27) and polycyclic aromatic hydrocarbons were degraded in 70?days. This work resulted in a successful trial of in situ bioremediation of oil-soaked marine sediments.Zhao, J., Tang, D., Qin, Y., Xu, H., Liu, Y., Wu, H., 2018. Characteristics of methane (CH4) diffusion in coal and its influencing factors in the Qinshui and Ordos basins. Energy & Fuels 32, 1196-1205. coefficient is usually used to evaluate the methane (CH4) diffusion properties in the coal matrix and is vital to coalbed methane (CBM) development. Although extensive literature on the CH4 diffusion coefficient can be obtained, most of them aim at the whole coal or coal rank instead of the macrolithotype. Additionally, the primary structure of coal was destroyed with the common determination technologies (e.g., the particle, steady-state, and inverse diffusion methods) which could result in great errors. In this work, to avoid the shortcomings of the above methods, nine flake coal samples from six coal mines in the Qinshui and Ordos Basins were prepared to determine the CH4 diffusion coefficient with the slab calculation model. Meanwhile, the effects on the diffusion from the gas pressure, temperature, water saturability, and coal pore structure, and the gas adsorption capacity controlled by the coal rank and macrolithotype, were analyzed to reveal the diffusion mechanism (mode) at the CBM reservoir and laboratory conditions. Results show that the CH4 diffusion coefficient, at an order of magnitude of 10–10 m2/s measured with the flake coal sample, is more truthful. High temperature and gas pressure, low water saturability, developed pore structure, and high gas adsorption capacity contribute to large CH4 diffusion coefficient. Although the higher rank coal has the larger gas adsorption capacity, the CH4 diffusion coefficient exhibits a “U” shape (first decreasing and then increasing) with the increase of coal rank due to more micropores in low- and high-rank coals than the middle-rank coal. From the bright to dull coals at the same coal rank, the decreasing development of pore structure and gas adsorption capacity causes the decreasing CH4 diffusion coefficient. But compared to the coal rank, the influence of coal macrolithotype on CH4 diffusion coefficient is weaker. In addition, the CH4 diffusion modes in coal mainly are transitional and Fick diffusions in the CBM reservoir and laboratory.Zhao, J., Zhao, Y., Liang, W., Song, S., Gao, Q., 2018. Semi-clathrate hydrate process of methane in porous media-mesoporous materials of SBA-15. Fuel 220, 446-452. hydrate based technology process in porous media is an effective method for gas storage and separation. The formation of methane hydrate in SBA-15, an ordered mesoporous silicon material, was measured with tetrahydrofuran (THF) and tetra-n-butyl ammonium bromide (TBAB) aqueous solution at different pressure and temperature·THF and TBAB were selected to lower the equilibrium pressure at which the gas hydrates can efficiently formed. At the experimental condition of 1.8?MPa–2.0?MPa, SBA-15 was proved to be effective to methane uptake in the hydrates. The results showed that mesoporous silica can help to get the fast-kinetic formation of methane hydrates. The temperature was almost steady and only had two slight increase no more than 0.5?K. The pressure dropped rapidly and then became gentle, which translated into an increase in gas uptake rapidly in the beginning of 100?min and then maintained stable till the end. The reaction rate quickly reached the peak then rapidly dropped and slowly decayed. The desirable kinetics parameters of final gas uptake capacity, average of reaction rate and conversion of gas to hydrate (%) were obtained at higher pressure and lower temperature while THF was better than TBAB. A gas uptake capacity of 91.13?mmol methane gas per mole water was achieved when the hydrates were formed in the presence of THF with SBA-15.Zhao, Q., Guo, L., Huang, Z., Chen, L., Jin, H., Wang, Y., 2018. Experimental investigation on enhanced oil recovery of extra heavy oil by supercritical water flooding. Energy & Fuels 32, 1685-1692. of deep extra heavy oil is a challenging work due to its high viscosity and high reservoir pressure. Supercritical water is first proposed as an injection agent, considering its favorable physiochemical properties. A novel flooding experimental system with a design temperature up to 450 °C and pressure up to 30 MPa was developed to demonstrate the feasibility of supercritical water flooding (SCWF) technology. A sand pack core with an adiabatic boundary was used to eliminate heat unbalance. The experimental results indicated that SCWF is a promising enhanced oil recovery technology. SCWF could significantly enhance oil recovery when compared with steam flooding and hot water flooding and reduce the oil viscosity simultaneously. SCWF at 25 MPa and 400 °C raised the recovery efficiency to 97.07% and reduced oil viscosity by 36.9%. The mechanism is attributed to the extraction heavy oil components into the water-rich phase by supercritical water and the formation of miscible flooding.Zheng, J., Feng, J.-Q., Zhou, L., Mbadinga, S.M., Gu, J.-D., Mu, B.-Z., 2018. Characterization of bacterial composition and diversity in a long-term petroleum contaminated soil and isolation of high-efficiency alkane-degrading strains using an improved medium. World Journal of Microbiology and Biotechnology 34, 34. community and diversity in a long-term petroleum-contaminated soil of an oilfield were characterized using 16S rRNA gene-based Illumina MiSeq high-throughput sequencing. Results indicated that Proteobacteria (49.11%) and Actinobacteria (24.24%) were the most dominant phyla, and the most abundant genera were Pseudoxanthomonas (8.47%), Luteimonas (3.64%), Alkanindiges (9.76%), Acinetobacter (5.26%) and Agromyces (8.56%) in the soil. Meanwhile a series of cultivations were carried out for isolation of alkane degraders from petroleum-contaminated soil with gellan gum and agar as gelling agents. And the isolates were classified by their 16S rRNA genes. Nine of the isolates including Enterobacter, Pseudomonas,Acinetobacter, Rhizobium, Bacillus, Sphingomonas, Paenibacillus, Variovorax and Rhodococcus showed strong biodegradability of alkane mixture (C9–C30) in a wide range of chain-length, which could be potentially applied in enhancement of bioremediation.Zheng, J., Thornton, P.E., Painter, S.L., Gu, B., Wullschleger, S.D., Graham, D.E., 2018. Modeling anaerobic soil organic carbon decomposition in Arctic polygon tundra: insights into soil geochemical influences on carbon mineralization. Biogeosciences Discussions 2018, 1-31. warming of Arctic ecosystems exposes soil organic matter (SOM) to accelerated microbial decomposition, potentially leading to increased emissions of carbon dioxide (CO2) and methane (CH4) that have a positive feedback on global warming. The fate of permafrost carbon is determined in large part by soil moisture, and a significant portion of carbon may thaw in wet, anoxic conditions. Current estimates of the magnitude and form of carbon emissions from Earth system models include significant uncertainties since the models do not explicitly represent anaerobic carbon decomposition. Here we coupled modeling principles developed in different disciplines, including a thermodynamically based microbial growth model for methanogenesis and iron reduction, a pool-based model to represent upstream carbon transformations, and a humic ion-binding model for dynamic pH simulation to build a more versatile carbon decomposition model framework that can be applied to soils under varying redox conditions. This new model framework was parameterized and validated using synthesized anaerobic incubation data from permafrost affected soils along a gradient of fine-scale thermal and hydrological variabilities across Arctic polygonal tundra. The model accurately simulated anaerobic CO2 production and its temperature sensitivity using data on labile carbon pools and fermentations rates as model constraints. CH4 production is strongly influenced by water content, pH, methanogen biomass, and presence of competing electron acceptors, resulting in high variability in its temperature sensitivity. This work provides new insights into the interactions of SOM pools, temperature increase, soil geochemical feedbacks, and resulting CO2 and CH4 production. The proposed anaerobic carbon decomposition framework presented here builds a mechanistic link between soil geochemistry and carbon mineralization, making it applicable over a wide range of soils under different environmental settings.Zheng, R., Li, S., Li, X., 2018. Sensitivity analysis of hydrate dissociation front conditioned to depressurization and wellbore heating. Marine and Petroleum Geology 91, 631-638. gas hydrate reservoir can be divided by a dissociation front into a dissociated zone and a hydrate zone during production. The advance of such a dissociation front greatly affects both the energy recovery potential and geological hazards prevention. In this paper, the advance of hydrate dissociation front has been elaborately investigated by means of numerical simulation. More specifically, depressurization and wellbore heating methods are used as development strategies in the reservoir simulation models, which are characterized by various geological and production parameters. Quantitative sensitivity analyses have been conducted through 14 simulation models representing diversified configurations of boundary condition, intrinsic hydrate reaction rate, intrinsic permeability, initial hydrate saturation, overall heat conductivity, wellbore heating temperature, and bottom-hole pressure. It has been found that the velocity of hydrate dissociation front is positively proportional to intrinsic hydrate reaction rate, intrinsic permeability, overall heat conductivity, wellbore heating temperature, and heat supply from the boundary. In contrast, increasing initial hydrate saturation and bottom-hole pressure reduce the velocity of hydrate dissociation front. Furthermore, the shape of dissociation front advance curve also varies with the aforementioned parameters. A concave shape of dissociation front advance curve is transformed into a convex one as the intrinsic permeability increases, which reveals the effect of fluid-flow controlling mechanism on the variation of dissociation front. From the sensitivity view of point, the average velocity of the dissociation front is strongly dependent on the overall heat conductivity, initial hydrate saturation, and bottom-hole pressure and weakly dependent on intrinsic hydrate reaction rate and intrinsic permeability. Quantitatively, the average velocity of hydrate dissociation front can be increased by 47% when the overall heat conductivity increases from 3.1?W/(m·K) to 8.0?W/(m·K), whereas it is rarely affected by the wellbore heating temperature.Zheng, Y., Harris, D.F., Yu, Z., Fu, Y., Poudel, S., Ledbetter, R.N., Fixen, K.R., Yang, Z.-Y., Boyd, E.S., Lidstrom, M.E., Seefeldt, L.C., Harwood, C.S., 2018. A pathway for biological methane production using bacterial iron-only nitrogenase. Nature Microbiology 3, 281-286. (CH4) is a potent greenhouse gas that is released from fossil fuels and is also produced by microbial activity, with at least one billion tonnes of CH4 being formed and consumed by microorganisms in a single year. Complex methanogenesis pathways used by archaea are the main route for bioconversion of carbon dioxide (CO2) to CH4 in nature. Here, we report that wild-type iron-iron (Fe-only) nitrogenase from the bacterium Rhodopseudomonas palustris reduces CO2 simultaneously with nitrogen gas (N2) and protons to yield CH4, ammonia (NH3) and hydrogen gas (H2) in a single enzymatic step. The amount of CH4 produced by purified Fe-only nitrogenase was low compared to its other products, but CH4 production by this enzyme in R. palustris was sufficient to support the growth of an obligate CH4-utilizing Methylomonas strain when the two microorganisms were grown in co-culture, with oxygen (O2) added at intervals. Other nitrogen-fixing bacteria that we tested also formed CH4 when expressing Fe-only nitrogenase, suggesting that this is a general property of this enzyme. The genomes of 9% of diverse nitrogen-fixing microorganisms from a range of environments encode Fe-only nitrogenase. Our data suggest that active Fe-only nitrogenase, present in diverse microorganisms, contributes CH4 that could shape microbial community interactions.Zhou, F., Gao, X., Yuan, H., Song, J., Chen, F., 2018. The distribution and seasonal variations of sedimentary organic matter in the East China Sea shelf. Marine Pollution Bulletin 129, 163-171. sampled the surface sediments of the East China Sea shelf (ECSS) in spring and autumn, 2014, and analyzed the biogenic element concentrations and stable carbon (δ13C) and nitrogen (δ15N) isotopic compositions to study the distribution and seasonal variations of sedimentary organic matter (OM). The average concentrations of TOC, TN and OP in autumn decreased obviously compared with those in spring. The increase of δ15N values in autumn indicated the priority utilization of 14N by bacterial decomposition activity. The values of δ13C were used to trace organic matter sources. The estimated percentages for terrestrial OM were in the range of 0–34.6%. They generally decreased seaward in nearshore areas, indicating the decrease of terrigenous influence. There was an obvious tongue-shaped region with relatively low percentages of terrestrial OM (<12%) in the northern part of the ECSS, which may be a reflection of the intrusion pathway of the outer seawater.Zhou, H.W., Zhong, J.C., Ren, W.G., Wang, X.Y., Yi, H.Y., 2018. Characterization of pore-fracture networks and their evolution at various measurement scales in coal samples using X-ray μCT and a fractal method. International Journal of Coal Geology 189, 35-49. characteristics of pore-fracture networks, as well as their evolution in coal during loading, are important for exploration of coalbed methane. In this study, the evolution of fracture networks in coal during loading was investigated using X-ray micro-Computed Tomography (X-ray μCT) with a uniaxial compression facility. The cross-sectional slices of the coal sample were obtained by μCT scanning at ten loading levels. The physical and geometrical parameters, such as porosity, fracture aperture, fracture density, and connectivity, were obtained by processing the 3D μCT data. Along with the self-similar characteristics of the 3D fracture networks, a simplified Sierpinski-like fractal model was proposed to further examine the evolution of the pore-fracture networks with higher measurement accuracy. The results showed that the developed fractal model had the ability to characterize the geometrical characteristics of the pore-fracture networks at various measurement scales. With the decreasing measurement scale r, the porosity and volumetric fractal dimensions of the pore-fracture networks increased, which were approximately linear and logarithmic curves with respect to log (1/r), respectively. At the measurement scale of 50?μm, the longitudinal cleavage fractures, which were parallel to or perpendicular to the joints, were generated during uniaxial compression. The fracture porosity, as well as the fracture density, increased with increasing axial stress. The fracture growth process could be divided into three stages: the initial stage, the stable growth stage, and the accelerated growth stage. At the measurement scale of 0.008?μm, the pore-fracture evolution in the coal sample under uniaxial compression occurred in four phases, namely, the pore compaction phase, the production phase of new fractures, the stable development phase of main fractures, and the accelerated production and development phase of the fractures. At the measurement scale of 0.5?μm, the coal permeability varied in a V-shaped curve with axial stress.Zhou, Y., Li, G., Jin, L., Zhou, J., Wang, J., Li, Y., Hu, H., 2018. In situ analysis of catalytic effect of calcium nitrate on Shenmu coal pyrolysis with pyrolysis vacuum ultraviolet photoionization mass spectrometry. Energy & Fuels 32, 1061-1069. investigate the effect of calcium mineral on the product distribution of low-rank coal pyrolysis, a Chinese subbituminous coal (Shenmu coal), and samples with 5% and 10% added calcium content, were selected to study with a homemade pyrolysis vacuum ultraviolet photoionization mass spectrometry (py-VUV-PIMS) system. In this system, secondary reactions of the pyrolysis products were generally inhibited because of in situ sampling, soft ionization, and high vacuum environment, which allowed direct detection of the initial pyrolytic products. Most evolved compounds during temperature-programmed heating from 30 to 650 °C were ionized by a VUV lamp (10.6 eV). The main products include five categories: alkenes, dienes, aromatics, phenols, and dihydroxy aromatics, which were formed via homolytic scission of weak bonds in side chains and bridges between aromatic nuclei in coal structure. The calcium mineral additives can dramatically affect pyrolytic product distribution, especially oxygen-containing compounds. The main reason is that calcium mineral plays a catalytic role in deoxygenation, which prompted incorporation of oxygen-containing compounds into corresponding aromatics, and resulted in the product of BTX levels increase significantly. The decrease in relative average molecular weight indicated the conversion of heavier components into lighter species, in terms of the observed m/z of the evolved gas components.Zhou, Z., Zhou, M., Yang, X., Niu, J., Meng, F., 2018. Sunlight irradiation triggers changes in the fouling potentials of natural dissolved organic matter. Science of The Total Environment 627, 227-234. photodegradation has a great impact on the composition and properties of natural dissolved organic matter (DOM) in aquatic environments, which potentially changes the behavior and roles of DOM in water treatment facilities. Here, we explored the effect of sunlight irradiation on membrane fouling behavior of two natural DOM (i.e., Aldrich humic acid (AHA) and Suwannee River DOM (SRNOM)), particularly in the presence of calcium ion (Ca(II)). Results showed that a long-term exposure (3?months) to sunlight during the summer led to decreases in the chromophores and molecular size of both DOM. The characterization by UV–vis spectral parameter DSlope350–400 (the slope of the log-transformed absorbance spectra in the range of 350–400?nm) indicated that sunlight-exposed DOM had a weaker Ca(II)-binding ability than unirradiated DOM, which could be attributable to the photochemically induced loss of carboxyl and phenolic groups. Additionally, AHA was found to be more susceptible to sunlight irradiation and Ca(II) addition than SRNOM, likely due to its higher aromaticity. Crucially, dead-end ultrafiltration tests showed that sunlight exposure of both AHA and SRNOM can reduce their fouling potential in the absence of Ca(II) and the presence of low Ca(II) (0.4?mM). In contrast, the addition of higher Ca(II) concentrations (2 and 3.6?mM) led to an increase in their fouling propensities. Overall, sunlight exposure can greatly alter the fouling behavior of natural DOM. This study provides a nexus between the naturally occurring transformation of DOM and its behavior (i.e., membrane fouling) in water treatment facilities.Zhu, C., Li, Y., Gong, H., Sang, Q., Li, Z., Dong, M., 2018. Adsorption and dissolution behaviors of carbon dioxide and n-dodecane mixtures in shale. Energy & Fuels 32, 1374-1386. cyclic injection is a promising method for enhanced shale oil recovery. However, the enhanced shale oil recovery mechanism is unclear, especially the adsorption and dissolution of CO2 and oil in kerogen. Therefore, it is of great importance to study the adsorption and dissolution mechanisms of CO2 and oil mixtures in shale. In this study, a new experimental apparatus was designed to test the change in the mole fractions of CO2 and oil before and after adsorption and dissolution at equilibrium conditions. For simplicity, n-dodecane (n-C12) was used as the oil. The adsorption and dissolution amounts of CO2 and n-C12 were obtained using a mathematical method. Moreover, the adsorption and dissolution characteristics of the CO2 and n-C12 mixtures in shale and the effect of pressure on the adsorption and dissolution amounts were studied. Finally, the swelling factor of the shale, which was caused by the dissolution of the mixtures, was calculated from the experimental results. The results show that dissolved n-C12 in shale could be replaced by CO2 when the mole fraction of CO2 in the free phase was larger than a threshold. The adsorption and dissolution amounts of CO2 and n-C12 increased with pressure. The lower pressure and larger mole fraction of CO2 enabled a lower swelling factor of shale. This study provides a straightforward method to experimentally determine the adsorption and dissolution properties of shale, which can be used to evaluate enhanced shale oil recovery by CO2 injection and the geological storage of CO2.Zhu, H., Zhong, D., Zhang, T., Liu, G., Yao, J., He, C., 2018. Diagenetic controls on the reservoir quality of fine-grained “tight” sandstones: A case study based on NMR analysis. Energy & Fuels 32, 1612-1623. description of diagenetic controls on reservoir quality in “tight” sandstones can be difficult because of the inherent fine grain size and complex components of such oil reservoirs. In this study, petrological techniques and nuclear magnetic resonance (NMR) analysis were applied to fine-grained tight sandstones with varying grain sizes in order to reveal the diagenetic controls on reservoir quality. Results show that macropores in tight sandstones occur mainly as intergranular and dissolution pores, whereas micropores are distributed within ductile rock fragments, clay, and mica minerals, as well as occurring as dissolution micropores. Pore size distribution (PSD)/T2 spectra display three distribution patterns: (i) a macropore-dominant bimodal distribution, (ii) a macropore–micropore bimodal distribution, and (iii) a micropore-dominant skewed distribution. A decrease in grain size correlates with weaker framework support of particles and thus more intensive mechanical compaction, resulting in the loss of both macroporosity and microporosity. Consequently, PSD change from macropore-dominant bimodal distributions to micropore-dominant skewed distributions as the pore type shifts from being dominated by macropores to intragranular micropores. In fine-grained sandstones, an increase in the abundance of ductile components corresponds to a loss of total porosity, related to the decrease in abundance of macropores, whereas the change in micropore abundance is negligible. This change is reflected in PSD by a shift from macropore-dominant bimodal distributions to macro–micropore bimodal distributions. The authigenic minerals in tight sandstone reservoirs occur mainly as late-stage carbonate minerals, and the precipitation of this carbonate cement preferentially occurs within macropores. When carbonate cement content is low, it has a limited influence on total porosity. However, it does significantly reduce the connectivity of the pore system, which is different from what might be expected in conventional sandstone reservoirs. Therefore, particle grain size, the abundance of ductile components, and late-stage cementation all contribute to the prediction of reservoir quality in oil-bearing tight sandstones.Zhuang, G.-C., Heuer, V.B., Lazar, C.S., Goldhammer, T., Wendt, J., Samarkin, V.A., Elvert, M., Teske, A.P., Joye, S.B., Hinrichs, K.-U., 2018. Relative importance of methylotrophic methanogenesis in sediments of the Western Mediterranean Sea. Geochimica et Cosmochimica Acta 224, 171-186. production of methane is an important terminal metabolic process during organic matter degradation in marine sediments. It is generally acknowledged that hydrogenotrophic and acetoclastic methanogenesis constitute the dominant pathways of methane production; the importance of methanogenesis from methylated compounds remains poorly understood. We conducted various biogeochemical and molecular genetic analyses to characterize substrate availability, rates of methanogenesis, and methanogen community composition, and further evaluated the contribution of different substrates and pathways for methane production in deltaic surface and subsurface sediments of the Western Mediterranean Sea. Major substrates representing three methanogenic pathways, including H2, acetate, and methanol, trimethylamine (TMA), and dimethylsulfide (DMS), were detected in the pore waters and sediments, and exhibited variability over depth and between sites. In accompanying incubation experiments, methanogenesis rates from various 14C labeled substrates varied as well, suggesting that environmental factors, such as sulfate concentration and organic matter quality, could significantly influence the relative importance of individual pathway. In particular, methylotrophic and hydrogenotrophic methanogenesis contributed to the presence of micromolar methane concentrations in the sulfate reduction zone, with methanogenesis from methanol accounting for up to 98% of the total methane production in the topmost surface sediment. In the sulfate-depleted zone, hydrogenotrophic methanogenesis was the dominant methanogenic pathway (67–98%), and enhanced methane production from acetate was observed in organic-rich sediment (up to 31%). Methyl coenzyme M reductase gene (mcrA) analysis revealed that the composition of methanogenic communities was generally consistent with the distribution of methanogenic activity from different substrates. This study provides the first quantitative assessment of methylotrophic methanogenesis in marine sediments and has important implications for marine methane cycling. The occurrence of methylotrophic methanogenesis in surface sediments could fuel the anaerobic oxidation of methane (AOM) in the shallow sulfate reduction zone. Release of methane produced from methylotrophic methanogenesis could be a source of methane efflux to the water column, thus influencing the benthic methane budgets.Ziyong, Z., Hangyu, Y., Xiaodan, G., 2018. Fuzzy fusion of geological and geophysical data for mapping hydrocarbon potential based on GIS. Petroleum Geoscience 24, 131-141. fusion of multiple data, including geographical, geological, geophysical, geochemical and dynamic data for hydrocarbon potential mapping, involves both a fusion algorithm and a convenient modelling platform. In this study, fuzzy logic and a geographical information system (GIS) are used to fuse geological and geophysical interpretations in mapping the gas potential of the Kazakhstan Marsel Territory Carboniferous system based on the assumed gas-accumulation model. Non-linear membership functions are used to transform the input data, while the gamma operator is used to combine the multiple datasets. Finally, the Carboniferous system targets, the Visean (C1v) and Serpukhovian (C1sr) units, are mapped. Gas testing in situ validated our results. ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download