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GEOCHEMISTRY ARTICLES – July 2019?Analytical ChemistryChia, H.E., Marsh, E.N.G., Biteen, J.S., 2019. Extending fluorescence microscopy into anaerobic environments. Current Opinion in Chemical Biology 51, 98-104.Dutta, M., Cai, J., Gui, W., Patterson, A.D., 2019. A review of analytical platforms for accurate bile acid measurement. Analytical and Bioanalytical Chemistry 411, 4541-4549.Rezazadeh, M., Seidi, S., Lid, M., Pedersen-Bjergaard, S., Yamini, Y., 2019. The modern role of smartphones in analytical chemistry. TrAC Trends in Analytical Chemistry 118, 548-555.Gas Chromatography/GC×GC/GC-MSKamatou, G., Sandasi, M., Tankeu, S., Vuuren, S.V., Viljoen, A., 2019. Headspace analysis and characterisation of South African propolis volatile compounds using GCxGC–ToF–MS. Revista Brasileira de Farmacognosia 29, 351-357.Kristensen, M., Christensen, P., Christensen, J.H., 2019. Optimization and validation of a derivatization method with boron trifluoride in ethanol for analysis of aromatic carboxylic acids in water. Journal of Chromatography A 1601, 21-26.Qian, C., Quan, W., Li, C., Xiang, Z., 2019. Analysis of volatile terpenoid compounds in Rhododendron species by multidimensional gas chromatography with quadrupole time-of-flight mass spectrometry. Microchemical Journal 149, 104064.Risum, A.B., Bro, R., 2019. Using deep learning to evaluate peaks in chromatographic data. Talanta 204, 255-260.Smirnov, A., Qiu, Y., Jia, W., Walker, D.I., Jones, D.P., Du, X., 2019. ADAP-GC 4.0: Application of clustering-assisted multivariate curve resolution to spectral deconvolution of gas chromatography–mass spectrometry metabolomics data. Analytical Chemistry 91, 9069-9077.Tammekivi, E., Vahur, S., Keki?ev, O., van der Werf, I.D., Toom, L., Herodes, K., Leito, I., 2019. Comparison of derivatization methods for the quantitative gas chromatographic analysis of oils. Analytical Methods 11, 3514-3522.Wu, Z., Mao, Y., Raza, M., Zhu, J., Feng, Y., Wang, S., Qian, Y., Yu, L., Lu, X., 2019. Surrogate fuels for RP-3 kerosene formulated by emulating molecular structures, functional groups, physical and chemical properties. Combustion and Flame 208, 388-401.Zhang, Y.-M., Zhang, Y.-Y., Zhang, Q., Lv, Y., Sun, T., Han, L., Bai, C.-C., Yu, Y.-J., 2019. Automatic peak detection coupled with multivariate curve resolution–alternating least squares for peak resolution in gas chromatography–mass spectrometry. Journal of Chromatography A 1601, 300-309.Zoccali, M., Tranchida, P.Q., Mondello, L., 2019. Fast gas chromatography-mass spectrometry: A review of the last decade. TrAC Trends in Analytical Chemistry 118, 444-452.Extraction TechniquesAlbero, B., Tadeo, J.L., Pérez, R.A., 2019. Ultrasound-assisted extraction of organic contaminants. TrAC Trends in Analytical Chemistry 118, 739-750.Capriotti, A.L., Cavaliere, C., La Barbera, G., Montone, C.M., Piovesana, S., Laganà, A., 2019. Recent applications of magnetic solid-phase extraction for sample preparation. Chromatographia 82, 1251-1274.David, V., Galaon, T., Bacalum, E., 2019. Sample enrichment by solid-phase extraction for reaching parts per quadrillion levels in environmental analysis. Chromatographia 82, 1139-1150.Faraji, M., Yamini, Y., Gholami, M., 2019. Recent advances and trends in applications of solid-phase extraction techniques in food and environmental analysis. Chromatographia 82, 1207-1249.Madikizela, L.M., Ncube, S., Chimuka, L., 2019. Recent developments in selective materials for solid phase extraction. Chromatographia 82, 1171-1189.Nascimento, M.M., Olímpio da Rocha, G., Bittencourt de Andrade, J., 2019. Simple and effective dispersive micro-solid phase extraction procedure for simultaneous determination of polycyclic aromatic compounds in fresh and marine waters. Talanta 204, 776-791.Rigobello-Masini, M., Pereira, E.A.O., Abate, G., Masini, J.C., 2019. Solid-phase extraction of glyphosate in the analyses of environmental, plant, and food samples. Chromatographia 82, 1121-1138.Rocío-Bautista, P., Termopoli, V., 2019. Metal–organic frameworks in solid-phase extraction procedures for environmental and food analyses. Chromatographia 82, 1191-1205.Speltini, A., Pastore, M., Merlo, F., Maraschi, F., Sturini, M., Dondi, D., Profumo, A., 2019. Humic acids pyrolyzed onto silica microparticles for solid-phase extraction of benzotriazoles and benzothiazoles from environmental waters. Chromatographia 82, 1275-1283.Wu, J.-H., He, C.-Y., 2019. Advances in cellulose-based sorbents for extraction of pollutants in environmental samples. Chromatographia 82, 1151-1169.Imaging: AFMAndo, T., 2019. High-speed atomic force microscopy. Current Opinion in Chemical Biology 51, 105-112.Benítez, J.J., Guzman-Puyol, S., Domínguez, E., Heredia, A., Heredia-Guerrero, J.A., 2019. Applications and potentialities of Atomic Force Microscopy in fossil and extant plant cuticle characterization. Review of Palaeobotany and Palynology 268, 125-132.Chen, Q., Liu, Q., 2019. Bitumen coating on oil sands clay minerals: A review. Energy & Fuels 33, 5933-5943.Chi, J., Zhang, W., Wang, L., Putnis, C.V., 2019. Direct observations of the occlusion of soil organic matter within calcite. Environmental Science & Technology 53, 8097-8104.Fatayer, S., Albrecht, F., Zhang, Y., Urbonas, D., Pe?a, D., Moll, N., Gross, L., 2019. Molecular structure elucidation with charge-state control. Science 365, 142-145.Wang, N., Collins, I.R., Webb, K.J., Wan, Q., Durkan, C., 2019. Probing the interactions of dolomite surfaces with oil at the molecular scale. Energy & Fuels 33, 6161-6169.Zhang, Y., Schulz, F., Rytting, B.M., Walters, C.C., Kaiser, K., Metz, J.N., Harper, M.R., Merchant, S.S., Mennito, A.S., Qian, K., Kushnerick, J.D., Kilpatrick, P.K., Gross, L., 2019. Elucidating the geometric substitution of petroporphyrins by spectroscopic analysis and atomic force microscopy molecular imaging. Energy & Fuels 33, 6088-6097.Zhang, G., Ranjith, P.G., Wu, B., Perera, M.S.A., Haque, A., Li, D., 2019. Synchrotron X-ray tomographic characterization of microstructural evolution in coal due to supercritical CO2 injection at in-situ conditions. Fuel 255, 115696.Imaging: SEM, TEM, HIMBlazevic, A., Albu, M., Mitsche, S., Rittmann, S.K.-M.R., Habler, G., Milojevic, T., 2019. Biotransformation of scheelite CaWO4 by the extreme thermoacidophile Metallosphaera sedula: Tungsten–microbial interface. Frontiers in Microbiology 10, 1492. doi: 1410.3389/fmicb.2019.01492.Cui, H., Liang, F., Ma, C., Zhong, N., Sha, Y., Ma, W., 2019. Pore evolution characteristics of Chinese marine shale in the thermal simulation experiment and the enlightenment for gas shale evaluation in South China. Geosciences Journal 23, 595-602.D'Angelo, J.A., 2019. Molecular structure of the cuticles of Dicroidium and Johnstonia (Corystospermaceae, Triassic, Argentina). Ecophysiological adaptations of two chemically indistinguishable, morphology-based taxa. Review of Palaeobotany and Palynology 268, 109-124.Fu, Y., Jiang, Y., Wang, Z., Hu, Q., Xie, J., Ni, G., Lei, Z., Zhou, K., Liu, X., 2019. Non-connected pores of the Longmaxi shale in southern Sichuan Basin of China. Marine and Petroleum Geology 110, 420-433.Hu, H., Hao, F., Guo, X., Yi, J., Shu, Z., Bao, H., Zhu, X., 2019. Effect of lithofacies on the pore system of over-mature Longmaxi shale in the Jiaoshiba area, Sichuan Basin, China. Marine and Petroleum Geology 109, 886-898.Ivanova, A., Mitiurev, N., Cheremisin, A., Orekhov, A., Kamyshinsky, R., Vasiliev, A., 2019. Characterization of organic layer in oil carbonate reservoir rocks and its effect on microscale wetting properties. Scientific Reports 9, 10667.Konadu, K.T., Harrison, S.T.L., Osseo-Asare, K., Sasaki, K., 2019. Transformation of the carbonaceous matter in double refractory gold ore by crude lignin peroxidase released from the white-rot fungus. International Biodeterioration & Biodegradation 143, 104735.Lai, J., Pang, X., Xu, F., Wang, G., Fan, X., Xie, W., Chen, J., Qin, Z., Zhou, Z., 2019. Origin and formation mechanisms of low oil saturation reservoirs in Nanpu Sag, Bohai Bay Basin, China. Marine and Petroleum Geology 110, 317-334.Lei, Z., Xu, H., Liu, Q., Li, W., Yan, D., Li, S., Lei, P., Yan, M., Li, J., 2019. The influence of multiple-stage oil emplacement on deeply buried marine sandstone diagenesis: A case study on the Devonian Donghe sandstones, Tabei Uplift, Tarim Basin, NW China. Marine and Petroleum Geology 110, 299-316.Li, G., Qin, Y., Wu, M., Zhang, B., Wu, X., Tong, G., Liu, J., 2019. The pore structure of the transitional shale in the Taiyuan formation, Linxing area, Ordos Basin. Journal of Petroleum Science and Engineering 181, 106183.Li, J., Lu, S., Jiang, C., Wang, M., Chen, Z., Chen, G., Li, J., Lu, S., 2019. Characterization of shale pore size distribution by NMR considering the influence of shale skeleton signals. Energy & Fuels 33, 6361-6372.Li, J., Zhang, H., Liu, P., Menguy, N., Roberts, A.P., Chen, H., Wang, Y., Pan, Y., 2019. Phylogenetic and structural identification of a novel magnetotactic Deltaproteobacteria strain, WYHR-1, from a freshwater lake. Applied and Environmental Microbiology 85, e00731-00719.Li, X., Chen, S., Wang, X., Zhu, Y., Chang, M., Uwamahoro, C., 2019. Pore structure heterogeneity of the Xiamaling Formation shale gas reservoir in the Yanshan Area of China: Evaluation of geological controlling factors. Acta Geologica Sinica - English Edition 93, 588-603.Liu, A.G., McMahon, S., Matthews, J.J., Still, J.W., Brasier, A.T., Marosi, D., 2019. Petrological evidence supports the death mask model for the preservation of Ediacaran soft-bodied organisms in South Australia: Reply. Geology 47, e474-e474.Liu, J., Jiang, Y., Yao, W., Jiang, X., Jiang, X., 2019. Molecular characterization of Henan anthracite coal. Energy & Fuels 33, 6215-6225.Mahoney, C., M?rz, C., Buckman, J., Wagner, T., Blanco-Velandia, V.-O., 2019. Pyrite oxidation in shales: Implications for palaeo-redox proxies based on geochemical and SEM-EDX evidence. Sedimentary Geology 389, 186-199.Oakes, R.L., Peck, V.L., Manno, C., Bralower, T.J., 2019. Degradation of internal organic matter is the main control on pteropod shell dissolution after death. Global Biogeochemical Cycles 33, 749-760.Papineau, D., De Gregorio, B.T., Sagar, J., Thorogate, R., Wang, J., Nittler, L., Kilcoyne, D.A., Marbach, H., Drost, M., Thornton, G., 2019. Fossil biomass preserved as graphitic carbon in a late Paleoproterozoic banded iron formation metamorphosed at more than 550°C. Journal of the Geological Society 176, 651.Qin, M., Cao, Z., Guo, J., Huang, Y., Sun, L., Dong, L., 2019. Characteristics of shale reservoir and sweet spot identification of the Lower Cambrian Niutitang Formation in northwestern Hunan Province, China. Acta Geologica Sinica - English Edition 93, 573-587.Scoma, A., Garrido-Amador, P., Nielsen, S.D., R?y, H., Kjeldsen, K.U., 2019. The polyextremophilic bacterium Clostridium paradoxum attains piezophilic traits by modulating its energy metabolism and cell membrane composition. Applied and Environmental Microbiology 85, e00802-00819.Tian, X., Zhang, Y., Zhuo, Q., Yu, Z., Guo, Z., 2019. Tight oil charging characteristics of the Lower Permian Fengcheng Formation in Mahu sag, Junggar Basin: evidence from fluid inclusions in alkaline minerals. Acta Petrolei Sinica 40, 646-659.Wang, C., Zhang, B., Hu, Q., Shu, Z., Sun, M., Bao, H., 2019. Laminae characteristics and influence on shale gas reservoir quality of lower Silurian Longmaxi Formation in the Jiaoshiba area of the Sichuan Basin, China. Marine and Petroleum Geology 109, 839-851.Zhao, D., Guo, Y., Wang, G., Mao, X., 2019. Characterizing nanoscale pores and its structure in coal: Experimental investigation. Energy Exploration & Exploitation 37, 1320-1347.Imaging: Xray CTCalo, C.M., Rizzutto, M.A., Watling, J., Furquim, L., Shock, M.P., Andrello, A.C., Appoloni, C.R., Freitas, F.O., Kistler, L., Zimpel, C.A., Hermenegildo, T., Neves, E.G., Pugliese, F.A., 2019. Study of plant remains from a fluvial shellmound (Monte Castelo, RO, Brazil) using the X-ray MicroCT imaging technique. Journal of Archaeological Science: Reports 26, 101902.Elkhoury, J.E., Shankar, R., Ramakrishnan, T.S., 2019. Resolution and limitations of X-Ray micro-CT with applications to sandstones and limestones. Transport in Porous Media 129, 413-425.Elwegaa, K., Emadi, H., 2019. Improving oil recovery from shale oil reservoirs using cyclic cold nitrogen injection – An experimental study. Fuel 254, 115716.Fuchs, S.J., Espinoza, D.N., Lopano, C.L., Akono, A.-T., Werth, C.J., 2019. Geochemical and geomechanical alteration of siliciclastic reservoir rock by supercritical CO2-saturated brine formed during geological carbon sequestration. International Journal of Greenhouse Gas Control 88, 251-260.Li, S., Liu, L., Chai, P., Li, X., He, J., Zhang, Z., Wei, L., 2019. Imaging hydraulic fractures of shale cores using combined positron emission tomography and computed tomography (PET-CT) imaging technique. Journal of Petroleum Science and Engineering 182, 106283.Wei, J., Liang, J., Lu, J., Zhang, W., He, Y., 2019. Characteristics and dynamics of gas hydrate systems in the northwestern South China Sea - Results of the fifth gas hydrate drilling expedition. Marine and Petroleum Geology 110, 287-298.Liquid Chromatography/LC-MS/SFCChen, X., Hua, L., Wang, Y., Hou, K., Jiang, J., Xie, Y., Li, H., 2019. Fast online two-dimensional analysis of monoterpenes using multi-capillary column high-pressure photoionization time-of-flight mass spectrometry. Chinese Journal of Chromatography 37, 904-910.Han, M., Kong, J., Yuan, J., He, H., Hu, J., Yang, S., Li, S., Zhang, L., Sun, C., 2019. Method development for simultaneous analyses of polycyclic aromatic hydrocarbons and their nitro-, oxy-, hydroxy- derivatives in sediments. Talanta 205, 120128.Hohrenk, L.L., Vosough, M., Schmidt, T.C., 2019. Implementation of chemometric tools to improve data mining and prioritization in LC-HRMS for nontarget screening of organic micropollutants in complex water matrixes. Analytical Chemistry 91, 9213-9220.Liu, S.-S., Yang, K., Sun, Z.-L., Zheng, X., Bai, X., Liu, Z.-Y., 2019. A novel two-dimensional liquid chromatography system for the simultaneous determination of three monoterpene indole alkaloids in biological matrices. Analytical and Bioanalytical Chemistry 411, 3857-3870.Losacco, G.L., Veuthey, J.-L., Guillarme, D., 2019. Supercritical fluid chromatography – mass spectrometry: Recent evolution and current trends. TrAC Trends in Analytical Chemistry 118, 731-738.Moulian, R., Sama, S.G., Garnier, C., Mounicou, S., Enrico, M., Jaurand, X., Lobinski, R., Giusti, P., Bouyssiere, B., Barrère-Mangote, C., 2019. Speciation of metals in asphaltenes by high-performance thin-layer chromatography and laser ablation inductively coupled plasma-mass spectrometry. Energy & Fuels 33, 6060-6068.Reymond, C., Le Masle, A., Colas, C., Charon, N., 2019. A rational strategy based on experimental designs to optimize parameters of a liquid chromatography-mass spectrometry analysis of complex matrices. Talanta 205, 120063.Risum, A.B., Bro, R., 2019. Using deep learning to evaluate peaks in chromatographic data. Talanta 204, 255-260.Song, C., Wang, W., Liu, Z., Liu, Y., Cai, X., 2019. Development and application of two-dimensional liquid chromatography for the analysis of polycyclic aromatic sulfur heterocycles in heavy oil. Chinese Journal of Chromatography 37, 750-758.Wolkenstein, K., 2019. Characterization of polycyclic aromatic hydrocarbons and their phenanthroperylene quinone precursors in fossil crinoids using liquid chromatography–atmospheric pressure photoionization mass spectrometry. Organic Geochemistry 136, 103892.Yang, C., Zhang, G., Serhan, M., Koivu, G., Yang, Z., Hollebone, B., Lambert, P., Brown, C.E., 2019. Characterization of naphthenic acids in crude oils and refined petroleum products. Fuel 255, 115849.Mass Spectroscopy/ICR-FTMS/OrbitrapCesar, J., Eiler, J., Dallas, B., Chimiak, L., Grice, K., 2019. Isotope heterogeneity in ethyltoluenes from Australian condensates, and their stable carbon site-specific isotope analysis. Organic Geochemistry 135, 32-37.Covas, T.R., Rocha, Y.d.S., Spigolon, A.L.D., Pereira, R.C.L., Valencia-Dávila, J.A., Rangel, M.D., Vaz, B.G., 2019. Evaluation of the effects of the simulated thermal evolution of a Type-I source rock on the distribution of basic nitrogen-containing compounds. Fuel 254, 115685.Ferey, J., Marguet, F., Laquerrière, A., Marret, S., Schmitz-Afonso, I., Bekri, S., Afonso, C., Tebani, A., 2019. A new optimization strategy for MALDI FTICR MS tissue analysis for untargeted metabolomics using experimental design and data modeling. Analytical and Bioanalytical Chemistry 411, 3891-3903.Hohrenk, L.L., Vosough, M., Schmidt, T.C., 2019. Implementation of chemometric tools to improve data mining and prioritization in LC-HRMS for nontarget screening of organic micropollutants in complex water matrixes. Analytical Chemistry 91, 9213-9220.Khatami, S., Deng, Y., Tien, M., Hatcher, P.G., 2019. Formation of water-soluble organic matter through fungal degradation of lignin. Organic Geochemistry 135, 64-70.Letourneau, M.L., Medeiros, P.M., 2019. Dissolved organic matter composition in a marsh-dominated estuary: Response to seasonal forcing and to the passage of a hurricane. Journal of Geophysical Research: Biogeosciences 124, 1545-1559.Min, D.W., Kim, K., Lui, K.H., Kim, B., Kim, S., Cho, J., Choi, W., 2019. Abiotic formation of humic-like substances through freezing-accelerated reaction of phenolic compounds and nitrite. Environmental Science & Technology 53, 7410-7418.Mitchell, J.M., Flight, R.M., Moseley, H.N.B., 2019. Small molecule isotope resolved formula enumeration: A methodology for assigning isotopologues and metabolite formulas in Fourier transform mass spectra. Analytical Chemistry 91, 8933-8940.Ning, C., Gao, Y., Zhang, H., Yu, H., Wang, L., Geng, N., Cao, R., Chen, J., 2019. Molecular characterization of dissolved organic matters in winter atmospheric fine particulate matters (PM2.5) from a coastal city of northeast China. Science of The Total Environment 689, 312-321.Palacio Lozano, D.C., Gavard, R., Arenas-Diaz, J.P., Thomas, M.J., Stranz, D.D., Mejía-Ospino, E., Guzman, A., Spencer, S.E.F., Rossell, D., Barrow, M.P., 2019. Pushing the analytical limits: new insights into complex mixtures using mass spectra segments of constant ultrahigh resolving power. Chemical Science 10, 6966-6978.Song, C., Wang, W., Liu, Z., Liu, Y., Cai, X., 2019. Development and application of two-dimensional liquid chromatography for the analysis of polycyclic aromatic sulfur heterocycles in heavy oil. Chinese Journal of Chromatography 37, 750-758.Spencer, R.G.M., Kellerman, A.M., Podgorski, D.C., Macedo, M.N., Jankowski, K., Nunes, D., Neill, C., 2019. Identifying the molecular signatures of agricultural expansion in Amazonian headwater streams. Journal of Geophysical Research: Biogeosciences 124, 1637-1650.Sun, Y., Feng, F., Nie, B., Cao, J., Zhang, F., 2019. High throughput identification of pentacyclic triterpenes in Hippophae rhamnoides using multiple neutral loss markers scanning combined with substructure recognition (MNLSR). Talanta 205, 120011.Tang, Y., Li, D., Cao, D., Xu, W., 2019. Extracting biomolecule collision cross sections from FT-ICR mass spectral line shape. Talanta 205, 120093.Yang, C., Zhang, G., Serhan, M., Koivu, G., Yang, Z., Hollebone, B., Lambert, P., Brown, C.E., 2019. Characterization of naphthenic acids in crude oils and refined petroleum products. Fuel 255, 115849.Ye, L., Chen, H., Jing, C., 2019. Sulfate reducing bacteria mobilize adsorbed antimonate by thioantimonate formation. Environmental Science & Technology Letters 6, 418-422.Zhang, Y., Schulz, F., Rytting, B.M., Walters, C.C., Kaiser, K., Metz, J.N., Harper, M.R., Merchant, S.S., Mennito, A.S., Qian, K., Kushnerick, J.D., Kilpatrick, P.K., Gross, L., 2019. Elucidating the geometric substitution of petroporphyrins by spectroscopic analysis and atomic force microscopy molecular imaging. Energy & Fuels 33, 6088-6097.Zheng, Q., Chen, Q., Cai, R., He, C., Guo, W., Wang, Y., Shi, Q., Chen, C., Jiao, N., 2019. Molecular characteristics of microbially mediated transformations of Synechococcus-derived dissolved organic matter as revealed by incubation experiments. Environmental Microbiology 21, 2533-2543.Ziegler, G., Gonsior, M., Fisher, D.J., Schmitt-Kopplin, P., Tamburri, M.N., 2019. Formation of brominated organic compounds and molecular transformations in dissolved organic matter (DOM) after ballast water treatment with sodium dichloroisocyanurate dihydrate (DICD). Environmental Science & Technology 53, 8235-8243.Zito, P., Podgorski, D.C., Johnson, J., Chen, H., Rodgers, R.P., Guillemette, F., Kellerman, A.M., Spencer, R.G.M., Tarr, M.A., 2019. Molecular-level composition and acute toxicity of photosolubilized petrogenic carbon. Environmental Science & Technology 53, 8235-8243.Mass Spectroscopy-OtherGiles, K., Ujma, J., Wildgoose, J., Pringle, S., Richardson, K., Langridge, D., Green, M., 2019. A cyclic ion mobility-mass spectrometry system. Analytical Chemistry 91, 8564-8573.Giorio, C., Moyroud, E., Glover, B.J., Kalberer, M., 2019. Direct depolymerization coupled to liquid extraction surface analysis-high-resolution mass spectrometry for the characterization of the surface of plant tissues. Analytical Chemistry 91, 8326-8333.Glock, N., Liebetrau, V., Vogts, A., Eisenhauer, A., 2019. Organic heterogeneities in foraminiferal calcite traced through the distribution of N, S, and I measured with NanoSIMS: A new challenge for element-ratio-based paleoproxies? Frontiers in Earth Science 7, 175. doi: 110.3389/feart.2019.00175.Johnson, J.T., Carrick, I.J., Eakins, G.S., McLuckey, S.A., 2019. Mirror switching for high-resolution ion isolation in an electrostatic linear ion trap. Analytical Chemistry 91, 8789-8794.Liu, S., Zuo, J., Lu, Y., Gao, L., Zhai, Y., Xu, W., 2019. Direct bacteria analysis using laserspray ionization miniature mass spectrometry. Analytical and Bioanalytical Chemistry 411, 4031-4040.McBride, E.M., Mach, P.M., Dhummakupt, E.S., Dowling, S., Carmany, D.O., Demond, P.S., Rizzo, G., Manicke, N.E., Glaros, T., 2019. Paper spray ionization: Applications and perspectives. TrAC Trends in Analytical Chemistry 118, 722-730.Moulian, R., Sama, S.G., Garnier, C., Mounicou, S., Enrico, M., Jaurand, X., Lobinski, R., Giusti, P., Bouyssiere, B., Barrère-Mangote, C., 2019. Speciation of metals in asphaltenes by high-performance thin-layer chromatography and laser ablation inductively coupled plasma-mass spectrometry. Energy & Fuels 33, 6060-6068.Nunome, Y., Kodama, K., Ueki, Y., Yoshiie, R., Naruse, I., Wagatsuma, K., 2019. Direct analysis of saturated hydrocarbons using glow discharge plasma ionization source for mass spectrometry. Talanta 204, 310-319.Saigusa, D., Saito, R., Kawamoto, K., Uruno, A., Kano, K., Aoki, J., Yamamoto, M., Kawamoto, T., 2019. Conductive adhesive film expands the utility of matrix-assisted laser desorption/ionization mass spectrometry imaging. Analytical Chemistry 91, 8979-8986.Sheraz, S., Tian, H., Vickerman, J.C., Blenkinsopp, P., Winograd, N., Cumpson, P., 2019. Enhanced ion yields using high energy water cluster beams for secondary ion mass spectrometry analysis and imaging. Analytical Chemistry 91, 9058-9068.Zhou, C., Wu, H., Zhang, X., Zhang, Y., Xie, W., Xu, W., 2019. High-throughput and direct sample screening using a laser spray ionization miniature mass spectrometer. Analytical Chemistry 91, 8808-8813.Metabolomics/LipidomicsBesseling, M.A., Hopmans, E.C., Koenen, M., van der Meer, M.T.J., Vreugdenhil, S., Schouten, S., Sinninghe Damsté, J.S., Villanueva, L., 2019. Depth-related differences in archaeal populations impact the isoprenoid tetraether lipid composition of the Mediterranean Sea water column. Organic Geochemistry 135, 16-31.Brailsford, F.L., Glanville, H.C., Golyshin, P.N., Marshall, M.R., Lloyd, C.E., Johnes, P.J., Jones, D.L., 2019. Nutrient enrichment induces a shift in dissolved organic carbon (DOC) metabolism in oligotrophic freshwater sediments. Science of The Total Environment 690, 1131-1139.Cubillos, C.F., Paredes, A., Yá?ez, C., Palma, J., Severino, E., Vejar, D., Grágeda, M., Dorador, C., 2019. Insights into the microbiology of the chaotropic brines of Salar de Atacama, Chile. Frontiers in Microbiology 10, 1611. doi: 1610.3389/fmicb.2019.01611.Ferey, J., Marguet, F., Laquerrière, A., Marret, S., Schmitz-Afonso, I., Bekri, S., Afonso, C., Tebani, A., 2019. A new optimization strategy for MALDI FTICR MS tissue analysis for untargeted metabolomics using experimental design and data modeling. Analytical and Bioanalytical Chemistry 411, 3891-3903.Kim, J., Kang, D., Lee, S.K., Kim, T.-Y., 2019. Deuterium oxide labeling for global omics relative quantification: Application to lipidomics. Analytical Chemistry 91, 8853-8863.Losacco, G.L., Veuthey, J.-L., Guillarme, D., 2019. Supercritical fluid chromatography – mass spectrometry: Recent evolution and current trends. TrAC Trends in Analytical Chemistry 118, 731-738.Marvasi, M., Cavalieri, D., Mastromei, G., Casaccia, A., Perito, B., 2019. Omics technologies for an in-depth investigation of biodeterioration of cultural heritage. International Biodeterioration & Biodegradation 144, 104736.Mitchell, J.M., Flight, R.M., Moseley, H.N.B., 2019. Small molecule isotope resolved formula enumeration: A methodology for assigning isotopologues and metabolite formulas in Fourier transform mass spectra. Analytical Chemistry 91, 8933-8940.Smirnov, A., Qiu, Y., Jia, W., Walker, D.I., Jones, D.P., Du, X., 2019. ADAP-GC 4.0: Application of clustering-assisted multivariate curve resolution to spectral deconvolution of gas chromatography–mass spectrometry metabolomics data. Analytical Chemistry 91, 9069-9077.Wang, R., Yin, Y., Zhu, Z.-J., 2019. Advancing untargeted metabolomics using data-independent acquisition mass spectrometry technology. 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Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 74, 63.Moulian, R., Sama, S.G., Garnier, C., Mounicou, S., Enrico, M., Jaurand, X., Lobinski, R., Giusti, P., Bouyssiere, B., Barrère-Mangote, C., 2019. Speciation of metals in asphaltenes by high-performance thin-layer chromatography and laser ablation inductively coupled plasma-mass spectrometry. Energy & Fuels 33, 6060-6068.Shalygin, A.S., Kozhevnikov, I.V., Kazarian, S.G., Martyanov, O.N., 2019. Spectroscopic imaging of deposition of asphaltenes from crude oil under flow. Journal of Petroleum Science and Engineering 181, 106205.Sheng, Q., Wang, G., Jin, N., Husein, M.M., Gao, J., 2019. Three-level structure change of asphaltenes undergoing conversion in a hydrogen donor solvent. Fuel 255, 115736.Tannous, J.H., de Klerk, A., 2019. Asphaltenes formation during thermal conversion of deasphalted oil. Fuel 255, 115786.Interfaces/EORAsgar, H., Ilavsky, J., Gadikota, G., 2019. Designing CO2-responsive multifunctional nanoscale fluids with tunable hydrogel behavior for subsurface energy recovery. Energy & Fuels 33, 5988-5995.Chen, S., Zhou, Y., Liu, H., Yang, J., Wei, Y., Zhang, J., 2019. Synthesis and physicochemical investigation of anionic–nonionic surfactants based on lignin for application in enhanced oil recovery. Energy & Fuels 33, 6247-6257.Gushchin, P.A., Cheremisin, A.N., Zobov, P.M., Shcherbakova, A.V., Khlebnikov, V.N., 2019. Use of dispersed solid matter of Bazhenov Formation for developing light oil reserves. Chemistry and Technology of Fuels and Oils 55, 165-173.Ivanova, A., Mitiurev, N., Cheremisin, A., Orekhov, A., Kamyshinsky, R., Vasiliev, A., 2019. Characterization of organic layer in oil carbonate reservoir rocks and its effect on microscale wetting properties. Scientific Reports 9, 10667.Mahzari, P., Jones, A.P., Oelkers, E.H., 2019. An integrated evaluation of enhanced oil recovery and geochemical processes for carbonated water injection in carbonate rocks. Journal of Petroleum Science and Engineering 181, 106188.Mamonov, A., Kvandal, O.A., Strand, S., Puntervold, T., 2019. Adsorption of polar organic components onto sandstone rock minerals and its effect on wettability and enhanced oil recovery potential by smart water. Energy & Fuels 33, 5954-5960.Sanyal, S., Bhui, U.K., Balaga, D., Kumar, S.S., 2019. Interaction study of montmorillonite-crude oil-brine: Molecular-level implications on enhanced oil recovery during low saline water flooding from hydrocarbon reservoirs. Fuel 254, 115725.Valiya Parambathu, A., Wang, L., Asthagiri, D., Chapman, W.G., 2019. Apolar behavior of hydrated calcite (101?4) surface assists in naphthenic acid adsorption. Energy & Fuels 33, 6119-6125.Wang, N., Collins, I.R., Webb, K.J., Wan, Q., Durkan, C., 2019. Probing the interactions of dolomite surfaces with oil at the molecular scale. Energy & Fuels 33, 6161-6169.Wijayanto, T., Kurihara, M., Kurniawan, T., Muraza, O., 2019. Experimental investigation of aluminosilicate nanoparticles for enhanced recovery of waxy crude oil. Energy & Fuels 33, 6076-6082.Heavy Oil ProductionChen, Q., Liu, Q., 2019. Bitumen coating on oil sands clay minerals: A review. Energy & Fuels 33, 5933-5943.UnconventionalsChandler, M.R., Mecklenburgh, J., Rutter, E., Lee, P., 2019. Fluid injection experiments in shale at elevated confining pressures: Determination of flaw sizes from mechanical experiments. Journal of Geophysical Research: Solid Earth 124, 5500-5520.Elwegaa, K., Emadi, H., 2019. Improving oil recovery from shale oil reservoirs using cyclic cold nitrogen injection – An experimental study. Fuel 254, 115716.Li, S., Liu, L., Chai, P., Li, X., He, J., Zhang, Z., Wei, L., 2019. Imaging hydraulic fractures of shale cores using combined positron emission tomography and computed tomography (PET-CT) imaging technique. Journal of Petroleum Science and Engineering 182, 106283.Wang, K., Wu, X., 2019. Downhole thermoelectric generation in unconventional horizontal wells. Fuel 254, 115530.Zhang, J., Zeng, Y., Slatt, R., 2019. XRF (X-ray fluorescence) applied to characterization of unconventional Woodford Shale (Devonian, U.S.A.) lateral well heterogeneity. Fuel 254, 115565.Recent SedimentsArmbrecht, L.H., Coolen, M.J.L., Lejzerowicz, F., George, S.C., Negandhi, K., Suzuki, Y., Young, J., Foster, N.R., Armand, L.K., Cooper, A., Ostrowski, M., Focardi, A., Stat, M., Moreau, J.W., Weyrich, L.S., 2019. Ancient DNA from marine sediments: Precautions and considerations for seafloor coring, sample handling and data generation. Earth-Science Reviews 196, 102887.Belt, S.T., Smik, L., K?seo?lu, D., Knies, J., Husum, K., 2019. A novel biomarker-based proxy for the spring phytoplankton bloom in Arctic and sub-arctic settings – HBI T25. Earth and Planetary Science Letters 523, 115703.Dr?ger, N., Plessen, B., Kienel, U., S?owiński, M., Ramisch, A., Tjallingii, R., Pinkerneil, S., Brauer, A., 2019. Hypolimnetic oxygen conditions influence varve preservation and δ13C of sediment organic matter in Lake Tiefer See, NE Germany. Journal of Paleolimnology 62, 181-194.Faust, J.C., Knies, J., 2019. Organic matter sources in North Atlantic fjord sediments. Geochemistry, Geophysics, Geosystems 20, 2872-2885.Hanke, U.M., Lima-Braun, A.L., Eglinton, T.I., Donnelly, J.P., Galy, V., Poussart, P., Hughen, K., McNichol, A.P., Xu, L., Reddy, C.M., 2019. Significance of perylene for source allocation of terrigenous organic matter in aquatic sediments. Environmental Science & Technology 53, 8244-8251.Legrand, B., Miras, Y., Beauger, A., Dussauze, M., Latour, D., 2019. Akinetes and ancient DNA reveal toxic cyanobacterial recurrences and their potential for resurrection in a 6700-year-old core from a eutrophic lake. Science of The Total Environment 687, 1369-1380.Li, X., Liu, W., Xu, L., 2019. Evaluation of lacustrine organic δ13C as a lake-level indicator: A case study of Lake Qinghai and the satellite lakes on the Tibetan Plateau. Palaeogeography, Palaeoclimatology, Palaeoecology 532, 109274.Luo, M., Gieskes, J., Chen, L., Scholten, J., Pan, B., Lin, G., Chen, D., 2019. Sources, degradation, and transport of organic matter in the New Britain Shelf-Trench Continuum, Papua New Guinea. Journal of Geophysical Research: Biogeosciences 124, 1680-1695.Martin, C., Ménot, G., Thouveny, N., Davtian, N., Andrieu-Ponel, V., Reille, M., Bard, E., 2019. Impact of human activities and vegetation changes on the tetraether sources in Lake St Front (Massif Central, France). Organic Geochemistry 135, 38-52.Quadra, G.R., Sobek, S., Paranaíba, J.R., Isidorova, A., Roland, F., do Vale, R., Mendon?a, R., 2019. High organic carbon burial but high potential for methane ebullition in the sediments of an Amazonian reservoir. Biogeosciences Discussions 2019, 1-25.Sayyad Amin, J., Rajabi Kuyakhi, H., Bahadori, A., 2019. Prediction of formation of polycyclic aromatic hydrocarbon (PAHs) on sediment of Caspian Sea using artificial neural networks. Petroleum Science and Technology 37, 1987-2000.Atmospheric GeochemistryLan, H., Holopainen, J., Hartonen, K., Jussila, M., Ritala, M., Riekkola, M.-L., 2019. Fully automated online dynamic in-tube extraction for continuous sampling of volatile organic compounds in air. Analytical Chemistry 91, 8507-8515.Lutz, A., Mohr, C., Le Breton, M., Lopez-Hilfiker, F.D., Priestley, M., Thornton, J.A., Hallquist, M., 2019. Gas to particle partitioning of organic acids in the boreal atmosphere. ACS Earth and Space Chemistry 3, 1279-1287.Ning, C., Gao, Y., Zhang, H., Yu, H., Wang, L., Geng, N., Cao, R., Chen, J., 2019. Molecular characterization of dissolved organic matters in winter atmospheric fine particulate matters (PM2.5) from a coastal city of northeast China. Science of The Total Environment 689, 312-321.Walhout, E.Q., Dorn, S.E., Martens, J., Berden, G., Oomens, J., Cheong, P.H.Y., Kroll, J.H., O’Brien, R.E., 2019. Infrared ion spectroscopy of environmental organic mixtures: Probing the composition of α-pinene secondary organic aerosol. Environmental Science & Technology 53, 7604-7612.Hydrosphere GeochemistryBesseling, M.A., Hopmans, E.C., Koenen, M., van der Meer, M.T.J., Vreugdenhil, S., Schouten, S., Sinninghe Damsté, J.S., Villanueva, L., 2019. Depth-related differences in archaeal populations impact the isoprenoid tetraether lipid composition of the Mediterranean Sea water column. Organic Geochemistry 135, 16-31.Brailsford, F.L., Glanville, H.C., Golyshin, P.N., Marshall, M.R., Lloyd, C.E., Johnes, P.J., Jones, D.L., 2019. Nutrient enrichment induces a shift in dissolved organic carbon (DOC) metabolism in oligotrophic freshwater sediments. Science of The Total Environment 690, 1131-1139.Clark, J.B., Neale, P., Tzortziou, M., Cao, F., Hood, R.R., 2019. A mechanistic model of photochemical transformation and degradation of colored dissolved organic matter. Marine Chemistry 214, 103666.Forde, O.N., Cahill, A.G., Mayer, K.U., Mayer, B., Simister, R.L., Finke, N., Crowe, S.A., Cherry, J.A., Parker, B.L., 2019. Hydro-biogeochemical impacts of fugitive methane on a shallow unconfined aquifer. Science of The Total Environment 690, 1342-1354.Gao, L., Gao, Y., Zong, H., Guo, L., 2019. Elucidating the hidden nonconservative behavior of DOM in large river-dominated estuarine and coastal environments. Journal of Geophysical Research: Oceans 124, 4258-4271.Geuer, J.K., Krock, B., Leefmann, T., Koch, B.P., 2019. Quantification, extractability and stability of dissolved domoic acid within marine dissolved organic matter. Marine Chemistry 215, 103669.Ishikawa, N.F., Butman, D., Raymond, P.A., 2019. Radiocarbon age of different photoreactive fractions of freshwater dissolved organic matter. Organic Geochemistry 135, 11-15.Khatami, S., Deng, Y., Tien, M., Hatcher, P.G., 2019. Formation of water-soluble organic matter through fungal degradation of lignin. Organic Geochemistry 135, 64-70.Lasareva, E.V., Parfenova, A.M., Romankevich, E.A., Lobus, N.V., Drozdova, A.N., 2019. Organic matter and mineral interactions modulate flocculation across Arctic river mixing zones. Journal of Geophysical Research: Biogeosciences 124, 1651-1664.Lee, H.-S., Hur, J., Lee, M.-H., Brogi, S.R., Kim, T.-W., Shin, H.-S., 2019. Photochemical release of dissolved organic matter from particulate organic matter: Spectroscopic characteristics and disinfection by-product formation potential. Chemosphere 235, 586-595.Letourneau, M.L., Medeiros, P.M., 2019. Dissolved organic matter composition in a marsh-dominated estuary: Response to seasonal forcing and to the passage of a hurricane. Journal of Geophysical Research: Biogeosciences 124, 1545-1559.Li, X., Li, C., Bai, Y., Shi, X., Su, R., 2019. Composition variations and spatiotemporal dynamics of dissolved organic matters during the occurrence of green tide (Ulva prolifera blooms) in the Southern Yellow Sea, China. Marine Pollution Bulletin 146, 619-630.Li, Y., Song, G., Massicotte, P., Yang, F., Li, R., Xie, H., 2019. Distribution, seasonality, and fluxes of dissolved organic matter in the Pearl River (Zhujiang) estuary, China. Biogeosciences 16, 2751-2770.Lin, B., Liu, Z., Eglinton, T.I., Kandasamy, S., Blattmann, T.M., Haghipour, N., de Lange, G.J., 2019. Perspectives on provenance and alteration of suspended and sedimentary organic matter in the subtropical Pearl River system, South China. Geochimica et Cosmochimica Acta 259, 270-287.Ma, C., Chen, X., Zhang, J., Zhu, Y., Kalkhajeh, Y.K., Chai, R., Ye, X., Gao, H.-j., Chu, W., Mao, J.-d., Thompson, M.L., 2019. Linking chemical structure of dissolved organic carbon and microbial community composition with submergence-induced soil organic carbon mineralization. Science of The Total Environment 692, 930-939.Mailloux, B.J., Kim, C., Kichuk, T., Nguyen, K., Precht, C., Wang, S., Jewell, T.N.M., Karaoz, U., Brodie, E.L., Williams, K.H., Beller, H.R., Buchholz, B.A., 2019. Paired RNA radiocarbon and sequencing analyses indicate the importance of autotrophy in a shallow alluvial aquifer. Scientific Reports 9, 10370.Sabadel, A.J.M., Van Oostende, N., Ward, B.B., Woodward, E.M.S., Van Hale, R., Frew, R.D., 2019. Characterization of particulate organic matter cycling during a summer North Atlantic phytoplankton bloom using amino acid C and N stable isotopes. Marine Chemistry 214, 103670.Sánchez-Murillo, R., Romero-Esquivel, L.G., Jiménez-Antillón, J., Salas-Navarro, J., Corrales-Salazar, L., ?lvarez-Carvajal, J., ?lvarez-McInerney, S., Bonilla-Barrantes, D., Gutiérrez-Sibaja, N., Martínez-Arroyo, M., Ortiz-Apuy, E., Salgado-Lobo, J., Villalobos-Morales, J., Esquivel-Hernández, G., Rojas-Jiménez, L.D., Gómez-Castro, C., Jiménez-Madrigal, Q., Vargas-Gutiérrez, O., Birkel, C., 2019. DOC transport and export in a dynamic tropical catchment. Journal of Geophysical Research: Biogeosciences 124, 1665-1679.Signorini, S.R., Mannino, A., Friedrichs, M.A.M., St-Laurent, P., Wilkin, J., Tabatabai, A., Najjar, R.G., Hofmann, E.E., Da, F., Tian, H., Yao, Y., 2019. Estuarine dissolved organic carbon flux from space: With application to Chesapeake and Delaware bays. Journal of Geophysical Research: Oceans 124, 3755-3778.Spencer, R.G.M., Kellerman, A.M., Podgorski, D.C., Macedo, M.N., Jankowski, K., Nunes, D., Neill, C., 2019. Identifying the molecular signatures of agricultural expansion in Amazonian headwater streams. Journal of Geophysical Research: Biogeosciences 124, 1637-1650.Wang, W.-L., Lee, C., Primeau, F.W., 2019. A Bayesian statistical approach to inferring particle dynamics from in-situ pump POC and chloropigment data from the Mediterranean Sea. Marine Chemistry 214, 103654.Wang, Y., Li, D.-W., Sachs, J.P., Hu, J., Cao, Y., Li, L., Zhang, H., Zhao, M., 2019. Vertical distribution of isoprenoid GDGTs in suspended particles from the East China Sea shelf and implications for sedimentary TEX86H records. Organic Geochemistry 136, 103895.Zheng, Q., Chen, Q., Cai, R., He, C., Guo, W., Wang, Y., Shi, Q., Chen, C., Jiao, N., 2019. Molecular characteristics of microbially mediated transformations of Synechococcus-derived dissolved organic matter as revealed by incubation experiments. Environmental Microbiology 21, 2533-2543.Zhou, Y., Martin, P., Müller, M., 2019. Composition and cycling of dissolved organic matter from tropical peatlands of coastal Sarawak, Borneo, revealed by fluorescence spectroscopy and parallel factor analysis. Biogeosciences 16, 2733-2749.Soil GeochemistryChi, J., Zhang, W., Wang, L., Putnis, C.V., 2019. Direct observations of the occlusion of soil organic matter within calcite. Environmental Science & Technology 53, 8097-8104.Fatichi, S., Manzoni, S., Or, D., Paschalis, A., 2019. A mechanistic model of microbially mediated soil biogeochemical processes: A reality check. Global Biogeochemical Cycles 33, 620-648.Girona-García, A., Badía-Villas, D., Jiménez-Morillo, N.T., González-Pérez, J.A., 2019. Changes in soil organic matter composition after Scots pine afforestation in a native European beech forest revealed by analytical pyrolysis (Py-GC/MS). Science of The Total Environment 691, 1155-1161.Jiménez-González, M.A., ?lvarez, A.M., Carral, P., Almendros, G., 2019. Chemometric assessment of soil organic matter storage and quality from humic acid infrared spectra. Science of The Total Environment 685, 1160-1168.Ma, C., Chen, X., Zhang, J., Zhu, Y., Kalkhajeh, Y.K., Chai, R., Ye, X., Gao, H.-j., Chu, W., Mao, J.-d., Thompson, M.L., 2019. Linking chemical structure of dissolved organic carbon and microbial community composition with submergence-induced soil organic carbon mineralization. Science of The Total Environment 692, 930-939.Mikutta, R., Turner, S., Schippers, A., Gentsch, N., Meyer-Stüve, S., Condron, L.M., Peltzer, D.A., Richardson, S.J., Eger, A., Hempel, G., Kaiser, K., Klotzbücher, T., Guggenberger, G., 2019. Microbial and abiotic controls on mineral-associated organic matter in soil profiles along an ecosystem gradient. Scientific Reports 9, 10294.Sugihara, S., Shibata, M., Mvondo Ze, A.D., Tanaka, H., Kosaki, T., Funakawa, S., 2019. Forest understories controlled the soil organic carbon stock during the fallow period in African tropical forest: a 13C analysis. Scientific Reports 9, 9835.Vinci, G., Mazzei, P., Bridoux, M., Drosos, M., Piccolo, A., 2019. Molecular characterization of organic matter in two calcareous soils: the effects of an acid decarbonation treatment. Analytical and Bioanalytical Chemistry 411, 5243-5253.Remote Sensing-Hydrocarbon SeepageDi, P., Feng, D., Chen, D., 2019. The distribution of dissolved methane and its air-sea flux in the plume of a seep field, Lingtou Promontory, South China Sea. Geofluids 2019, 3240697.Dupuis, M., Imbert, P., Odonne, F., Vendeville, B., 2019. Mud volcanism by repeated roof collapse: 3D architecture and evolution of a mud volcano cluster offshore Nigeria. Marine and Petroleum Geology 110, 368-387.He, Z., Zhang, M., Ning, Z., Guo, C., Zhang, C., Du, J., 2019. Genetic quantitative techniques combined with continuous electromagnetic profiling to identify subtle oil and gas reservoirs. Geomicrobiology Journal 36, 705-714.Jordan, S.F., O'Reilly, S.S., Praeg, D., Dove, D., Facchin, L., Romeo, R., Szpak, M., Monteys, X., Murphy, B.T., Scott, G., McCarron, S.S., Kelleher, B.P., 2019. Geophysical and geochemical analysis of shallow gas and an associated pockmark field in Bantry Bay, Co. Cork, Ireland. Estuarine, Coastal and Shelf Science 225, 106232.Kim, J., Yu, S., Yun, S.-T., Kim, K.-H., Kim, J.-H., Shinn, Y.-J., Chae, G., 2019. CO2 leakage detection in the near-surface above natural CO2-rich water aquifer using soil gas monitoring. International Journal of Greenhouse Gas Control 88, 261-271.Quadra, G.R., Sobek, S., Paranaíba, J.R., Isidorova, A., Roland, F., do Vale, R., Mendon?a, R., 2019. High organic carbon burial but high potential for methane ebullition in the sediments of an Amazonian reservoir. Biogeosciences Discussions 2019, 1-25.Signorini, S.R., Mannino, A., Friedrichs, M.A.M., St-Laurent, P., Wilkin, J., Tabatabai, A., Najjar, R.G., Hofmann, E.E., Da, F., Tian, H., Yao, Y., 2019. Estuarine dissolved organic carbon flux from space: With application to Chesapeake and Delaware bays. Journal of Geophysical Research: Oceans 124, 3755-3778.Tang, J., Xu, Y., Wang, G., Huang, J., Han, W., Yao, Z., Zhu, Z., 2019. Methane in soil gas and its migration to the atmosphere in the Dawanqi oilfield, Tarim Basin, China. Geofluids 2019, 1693746.Ancient SeepageZhu, B., Ge, L., Yang, T., Jiang, S., Lv, X., 2019. Stable isotopes and rare earth element compositions of ancient cold seep carbonates from Enza River, northern Apennines (Italy): Implications for fluids sources and carbonate chimney growth. Marine and Petroleum Geology 109, 434-448.AbstractsAl-Areeq, N.M., Maky, A.F., Abu-Elata, A.S., Essa, M.A., Bamumen, S.S., Al-Ramisy, G.A., 2019. Comprehensive study on the conventional petroleum system of the Masilah oilfields, Sayun-Masilah Basin, Yemen. Journal of Petroleum Science and Engineering 181, 106193. Masilah oilfields are rich-oil provinces in the Sayun-Masilah Basin. The petroleum system including essential elements and processes is a very important for understanding and development of oilfield to further explore hydrocarbons in the whole basin. Integrated geochemical, geological, petrological and petrophysical analyses were performed on the source and reservoir rocks in the Masilah oilfields to gives information about the complete petroleum system. The Masilah oilfields filled with syn- and post-rift sediments, including a self-contained source-reservoir system. The geochemical results indicate that the organic-rich shales of the Madbi Formation are considered as oil-source rocks, with high total organic carbon content of more than 5.0?wt% TOC and oil-prone kerogen Types II and I. The Madbi shales are currently characterized by thermally mature level, within the oil generation window. Geochemical biomarker correlations of oil-source rock indicate that there is a genetic link between the oils and the Late Jurassic Madbi shale source rock in the Masilah oilfields. Therefore, the geochemical characteristics of the Madbi source rock have been collaborated into basin models and illustrate that the Madbi source rock had passed the peak-oil generation window during the Late Cretaceous to present-day and that large amounts of oil were generated. The generated oil was expelled and migrated to the overlain Early Cretaceous Qishn clastic reservoir rocks through faults during the Oligocene-Middle Miocene. The oil was then accumulated and trapped into horst and tilted fault blocks that initial formed during the Late Jurassic-Early Cretaceous rifting.Al-Khafaji, A.J., Al Najm, F.M., Al Ibrahim, R.N., Sadooni, F.N., 2019. Geochemical investigation of Yamama crude oils and their inferred source rocks in the Mesopotamian Basin, Southern Iraq. Petroleum Science and Technology 37, 2025-2033. oil samples from the Yamama reservoirs and ten extracts of purported source rocks from sixteen wells in the Mesopotamian Basin, Southern Iraq have been analyzed using GC, GC/MS and Stable Carbon Isotope. Yamama oils were non-biodegraded, moderate to higher maturity based on C27Ts of range from 0.17 to 0.77and TAS3 of 0.3 to 0.63, marine carbonate and marl source rocks, deposited under saline, anoxic conditions. Two oil groups were investigated based on the results of the geochemical analysis. These oils have similarly biomarkers ratios to those of the Middle Jurassic to Early Cretaceous source rocks in the Mesopotamian Basin.Albero, B., Tadeo, J.L., Pérez, R.A., 2019. Ultrasound-assisted extraction of organic contaminants. TrAC Trends in Analytical Chemistry 118, 739-750. extraction is an efficient environmental friendly technique, since the solvent volume required in sample preparation is reduced and the extraction time is shortened in comparison to classical extraction procedures. Ultrasound radiation has been primarily applied to the extraction of analytes from solid samples. However, an important increase in the application of ultrasounds in the extraction of liquid samples has been observed lately, coupled to new microextraction techniques. Several improvements have been applied to these techniques, such as the use of ionic liquids or surfactants, as green solvents. This review discusses the application of different ultrasound-assisted techniques in the analysis of frequently occurring organic contaminants in food and environmental samples, mainly focused on the works published in the last five years.Alizadeh, B., Seyedali, S.R., Sarafdokht, H., 2019. Effect of bitumen and migrated oil on hydrocarbon generation kinetic parameters derived from Rock-Eval pyrolysis. Petroleum Science and Technology 37, 2114-2121. immature whole rock and related bitumen-extracted samples were pyrolyzed. Investigating the influence of high molecular weight hydrocarbons and degradation products of non-hydrocarbon constituents of bitumen and associated migrated oil (i.e. resins and asphaltenes) on petroleum generation kinetic parameters derived from Rock-Eval pyrolysis is the main aim of this study. Based on the optimized kinetic parameters, frequency factor values of the bitumen-free samples show an obvious increase compared to whole rocks, while the range of activation energies for them is narrower. On the other hand, the predicted geological temperatures of the onset (TR 10%) and the peak hydrocarbon generation (geological Tmax) from the whole rocks are generally lower than the corresponding extracted samples. In other words, the whole rock samples underestimate the petroleum formation temperatures. Thus, the results of this study suggest the extraction of bitumen prior to Rock-Eval pyrolysis in order to obtain precise kinetic parameters for the source rocks bearing a large amounts of heavy bitumen or migrated oil.Aminzadeh, R., Nikazar, M., Dabir, B., 2019. Determining the occurrence time of different stages of asphaltene aggregation using molecular dynamics simulations. Petroleum Science and Technology 37, 2101-2107. work presents a framework for future studies to better understand the appropriate time to include chemical inhibitors at different stages of asphaltene aggregation in the oil. For this purpose, molecular dynamics (MD) simulations were performed to study the aggregation of asphaltene molecules in heptane, in terms of strength, dynamics, and the occurrence time of each stage of aggregation from single molecules to a large flocculate. Results indicate that the nucleation of nanoaggregates begins prior to 10?ns, clusters start forming at 98?ns, and flocculation happens after 120?ns. It was also observed that the final flocculate had a globular shape.Anderson, L.D., Bebout, G.E., Izawa, M.R.M., Bridge, N.J., Banerjee, N.R., 2019. Chemical alteration and preservation of sedimentary/organic nitrogen isotope signatures in a 2.7 Ga seafloor volcanic sequence. International Journal of Astrobiology 18, 235-250. to lobate volcanic flows and brecciated hyaloclastite units in the Abitibi greenstone belt allow investigation of Late Arch?an seafloor alteration and associated incorporation into these rocks of nitrogen (N) biogeochemical signatures. In this suite (the Blake River Group), hyaloclastite units containing putative microbial ichnofossils are particularly enriched in large-ion lithophile elements (K, Rb, Ba, Cs), B, and Li, consistent with their having experienced the greatest fluid–rock interaction during subseafloor hydrothermal alteration. Similarly, silicate-δ18O and δ15N values for samples from the hyaloclastites show the greatest shifts from plausible magmatic values. The chemical and isotopic patterns in these tholeiitic igneous rocks greatly resemble those in modern altered seafloor basalts, consistent with the preservation of an Arch?an seafloor alteration signature. The N enrichments and shifts in δ15N appear to reflect stabilization of illite and interaction with fluids carrying sedimentary/organic signatures. Enrichments of N (and the δ15N of this N) in altered glass volcanic rocks on Earth's modern and ancient seafloor point to the potential utility of N for tracing past and present biogeochemical processes in similar rocks at/near the Mars surface.Ando, T., 2019. High-speed atomic force microscopy. Current Opinion in Chemical Biology 51, 105-112. atomic force microscopy (HS-AFM) is a unique tool for molecular imaging. It can directly visualize protein molecules during their functional activity at high spatiotemporal resolution, without a marker being attached to the molecules. Molecular dynamics filmed with HS-AFM can provide mechanistic insights into the functional molecular processes that are hard to be attained with other approaches. In this mini review, I highlight some of recent relevant studies of proteins by HS-AFM imaging after brief descriptions of AFM and HS-AFM.Armbrecht, L.H., Coolen, M.J.L., Lejzerowicz, F., George, S.C., Negandhi, K., Suzuki, Y., Young, J., Foster, N.R., Armand, L.K., Cooper, A., Ostrowski, M., Focardi, A., Stat, M., Moreau, J.W., Weyrich, L.S., 2019. Ancient DNA from marine sediments: Precautions and considerations for seafloor coring, sample handling and data generation. Earth-Science Reviews 196, 102887. study of ancient DNA (aDNA) from sediments (sedaDNA) offers great potential for paleoclimate interpretation, and has recently been applied as a tool to characterise past marine life and environments from deep ocean sediments over geological timescales. Using sedaDNA, palaeo-communities have been detected, including prokaryotes and eukaryotes that do not fossilise, thereby revolutionising the scope of marine micropalaeontological research. However, many studies to date have not reported on the measures taken to prove the authenticity of sedaDNA-derived data from which conclusions are drawn. aDNA is highly fragmented and degraded and extremely sensitive to contamination by non-target environmental DNA. Contamination risks are particularly high on research vessels, drilling ships and platforms, where logistics and facilities do not yet allow for sterile sediment coring, and due consideration needs to be given to sample processing and analysis following aDNA guidelines. This review clarifies the use of aDNA terminology, discusses common pitfalls and highlights the urgency behind adopting new standards for marine sedaDNA research, with a focus on sampling optimisation to facilitate the incorporation of routine sedaDNA research into International Ocean Discovery Program (IODP) operations. Currently available installations aboard drilling ships and platforms are reviewed, improvements suggested, analytical approaches detailed, and the controls and documentation necessary to support the authenticity of aDNA retrieved from deep-sea sediment cores is outlined. Beyond practical considerations, concepts relevant to the study of past marine biodiversity based on sedaDNA, and the applicability of the new guidelines to the study of other contamination-susceptible environments (permafrost and outer space) are discussed.Asgar, H., Ilavsky, J., Gadikota, G., 2019. Designing CO2-responsive multifunctional nanoscale fluids with tunable hydrogel behavior for subsurface energy recovery. Energy & Fuels 33, 5988-5995. ability to direct subsurface fluid flow or achieve a high level of control on permeability in subsurface environments necessitates the development of tunable novel subsurface fluids. These multifunctional fluids should have the potential to form hydrogels to divert flow or enhance fracture networks at elevated pressures, ability to transport proppants, undergo reversible transformations from gel-like to fluid-like in response to chemical- or pressure-based perturbations, and have improved CO2 carrying capacity for enhancing the miscibility and flowability of oil and gas. In this paper, we discuss the development of multifunctional nanofluids constructed from silica (SiO2) nanoparticles and poly(allylamine) (PAA), amine-bearing polymer chains with high affinity for CO2. A 2-fold increase in CO2 absorption in SiO2–PAA nanofluids compared to the pure polymer was noted. Upon CO2 absorption, the weakly interacting polymeric chains around the nanoparticles formed relatively compact hydrogels. Time-resolved ultrasmall-angle X-ray scattering/small-angle X-ray scattering measurements showed the transition from swollen branched polymers to Gaussian coils with an increased exposure to CO2. Further, CO2-induced hydrogel formation in aqueous fluids bearing 1 wt % SiO2–PAA nanofluids occurred at room temperature, unlike in fluids bearing 1 wt % PAA. These observations point to the feasibility of forming hydrogels at lower temperatures and pressures using novel nanofluids as opposed to using the pure polymer. The ability to tune the structures and morphologies of these fluids expands the potential applications of these fluids in a wide range of subsurface environments.Auladell, A., Sánchez, P., Sánchez, O., Gasol, J.M., Ferrera, I., 2019. Long-term seasonal and interannual variability of marine aerobic anoxygenic photoheterotrophic bacteria. The ISME Journal 13, 1975-1987. studied the long-term temporal dynamics of the aerobic anoxygenic phototrophic (AAP) bacteria, a relevant functional group in the coastal marine microbial food web, using high-throughput sequencing of the pufM gene coupled with multivariate, time series and co-occurrence analyses at the Blanes Bay Microbial Observatory (NW Mediterranean). Additionally, using metagenomics, we tested whether the used primers captured accurately the seasonality of the most relevant AAP groups. Phylogroup K (Gammaproteobacteria) was the greatest contributor to community structure over all seasons, with phylogroups E and G (Alphaproteobacteria) being prevalent in spring. Diversity indices showed a clear seasonal trend, with maximum values in winter, which was inverse to that of AAP abundance. Multivariate analyses revealed sample clustering by season, with a relevant proportion of the variance explained by day length, temperature, salinity, phototrophic nanoflagellate abundance, chlorophyll a, and silicate concentration. Time series analysis showed robust rhythmic patterns of co-occurrence, but distinct seasonal behaviors within the same phylogroup, and even within different amplicon sequence variants (ASVs) conforming the same operational taxonomic unit (OTU). Altogether, our results picture the AAP assemblage as highly seasonal and recurrent but containing ecotypes showing distinctive temporal niche partitioning, rather than being a cohesive functional group.Azmy, K., 2019. Carbon-isotope stratigraphy of the SPICE event (Upper Cambrian) in eastern Laurentia: implications for global correlation and a potential reference section. Geological Magazine 156, 1311-1322. δ13C profile from the lower interval of the Martin Point section in western Newfoundland (Canada) spans the Upper Cambrian (uppermost Franconian – lowermost Trempealeauan). The investigated interval (～110 m) is a part of the Green Point Formation of the Cow Head Group and consists of the upper part of the Tucker Cove Member (topmost part of the Shallow Bay Formation) and the lowermost part of the Martin Point Member (bottom of the Green Point Formation). It is formed of rhythmites of marine carbonates alternating with shales and minor conglomeratic interbeds. Multiscreening petrographic and geochemical techniques have been utilized to evaluate the preservation of the investigated lime mudstones. The δ13C and δ18O values of the sampled micrites (?4.8 ‰ to +1.0 ‰ VPDB and ?8.2 ‰ to ?5.3 ‰ VPDB, respectively) have insignificant correlation (R2 = 0.01), as similarly do the δ13C values with their Sr counterparts (R2 = 0.07), which supports the preservation of at least near-primary δ13C signatures that can be utilized to construct a reliable high-resolution carbon-isotope profile for global correlations. The δ13C profile exhibits two main negative excursions: a lower excursion (～4 ‰) that reaches its maximum at the bottom of the section and an upper narrow excursion (～6 ‰) immediately above the boundary of the Tucker Cove/Martin Point members (Shallow Bay Formation – Green Point Formation boundary). The lower excursion may be correlated with the global SPICE event, whereas the upper excursion may match with a post-SPICE event that has been also recognized in profiles of equivalent sections on different palaeocontinents.Bachran, M., Kluge, S., Lopez-Fernandez, M., Cherkouk, A., 2019. Microbial diversity in an arid, naturally saline environment. Microbial Ecology 78, 494-505. Arava Valley in is a rock desert within the Great African Rift valley. Soil from this area is covered with a salt crust. Here, we report microbial diversity from arid, naturally saline samples collected near Ein Yahav from the Arava Valley by culture-independent as well as culture-dependent analysis. High-throughput sequencing of the hypervariable region V4 of the 16S rRNA gene revealed that the microbial community consists of halophiles from the domain Bacteria as well as Archaea. Bacterial diversity was mainly represented by the genus Salinimicrobium of the order Flavobacteriales within the phylum Bacteroidetes, from the gammaproteobacterial orders Alteromonadales and Oceanospirillales as well as representatives from the order Bacillales of the phylum Firmicutes. Archaeal diversity was dominated by euryarchaeal Halobacteria from the orders Halobacteriales, Haloferacales, and Natrialbales. But more than 40% of the sequences affiliated with Archaea were assigned to unknown or unclassified archaea. Even if taxonomic resolution of the 16S rRNA gene V4 region for Archaea is limited, this study indicates the need of further and more detailed studies of Archaea. By using culture-dependent analysis, bacteria of the order Bacillales as well as archaea from all three halobacterial orders Halobacteriales, Haloferacales, and Natrialbales including potentially novel species from the genera Halorubrum and Haloparvum were isolated.Baggenstos, D., H?berli, M., Schmitt, J., Shackleton, S.A., Birner, B., Severinghaus, J.P., Kellerhals, T., Fischer, H., 2019. Earth’s radiative imbalance from the Last Glacial Maximum to the present. Proceedings of the National Academy of Sciences 116, 14881-1488.: Earth’s radiative imbalance determines whether energy is flowing into or out of the ocean–atmosphere system. The present, anthropogenic, positive imbalance drives global warming. This study reconstructs the radiative imbalance for the last deglaciation, ～20,000 to 10,000 y ago. During the deglaciation, a positive imbalance was maintained for several thousand years, which brought the climate system from the last ice age into the Holocene warm period. We show that the imbalance varied significantly during this time, possibly due to changes in ocean circulation that affect the radiative energy fluxes, highlighting the importance of internal variability in Earth’s energy budget.Abstract: Earth’s radiative imbalance determines whether energy is flowing into or out of the ocean–atmosphere system. The present, anthropogenic, positive imbalance drives global warming. This study reconstructs the radiative imbalance for the last deglaciation, ～20,000 to 10,000 y ago. During the deglaciation, a positive imbalance was maintained for several thousand years, which brought the climate system from the last ice age into the Holocene warm period. We show that the imbalance varied significantly during this time, possibly due to changes in ocean circulation that affect the radiative energy fluxes, highlighting the importance of internal variability in Earth’s energy budget.The energy imbalance at the top of the atmosphere determines the temporal evolution of the global climate, and vice versa changes in the climate system can alter the planetary energy fluxes. This interplay is fundamental to our understanding of Earth’s heat budget and the climate system. However, even today, the direct measurement of global radiative fluxes is difficult, such that most assessments are based on changes in the total energy content of the climate system. We apply the same approach to estimate the long-term evolution of Earth’s radiative imbalance in the past. New measurements of noble gas-derived mean ocean temperature from the European Project for Ice Coring in Antarctica Dome C ice core covering the last 40,000 y, combined with recent results from the West Antarctic Ice Sheet Divide ice core and the sea-level record, allow us to quantitatively reconstruct the history of the climate system energy budget. The temporal derivative of this quantity must be equal to the planetary radiative imbalance. During the deglaciation, a positive imbalance of typically +0.2 W?m?2 is maintained for ～10,000 y, however, with two distinct peaks that reach up to 0.4 W?m?2 during times of substantially reduced Atlantic Meridional Overturning Circulation. We conclude that these peaks are related to net changes in ocean heat uptake, likely due to rapid changes in North Atlantic deep-water formation and their impact on the global radiative balance, while changes in cloud coverage, albeit uncertain, may also factor into the picture.Bai, Y., Azamdzhon, M., Wang, S., Fang, X., Guo, H., Zhou, P., Chen, C., Liu, X., Jia, S., Wang, Q., 2019. An evaluation of biological and climatic effects on plant n-alkane distributions and δ2Halk in a field experiment conducted in central Tibet. Organic Geochemistry 135, 53-63. distributions of long chain n-alkanes and their hydrogen isotope values (δ2Halk) can be used to investigate paleoclimatic changes, but, as yet, the degree to which plant types, temperature and/or hydrology may drive such variations, cannot be discriminated. Seven co-occurring herbaceous plants (angiosperms) were studied in climate-controlled growing conditions in an open-top chamber located in Naqu, Tibet, in 2015 and 2017, using generalized n-alkane parameters, viz. n-alkane concentrations (Concalk), the carbon preference index (CPI) and the average chain length (ACL), and δ2Halk values. These plants were subjected to warming (W, spanning a < 4?°C mean annual temperature (MAT) gradient) and the amount of water that plants received (100% precipitation differences) conditions in 2015 and 2017, respectively. Growth experiments showed that: (1) No significant relationships were found between n-alkane parameters (Concalk, ACL and CPI) and temperature (a 4?°C difference) or precipitation (100% precipitation differences); (2) The δ2Halk increased ca. 10–30‰ during W 4?°C conditions, with differences in the sensitivity of responses to W between different species. During P treatments, the variability in δ2Halk values was close to that caused by a W 4?°C response; and 3) the interspecies variability in n-alkane distributions and δ2Halk (ca. 30–50‰) was higher than that caused by these P and W responses. These results highlight the importance of the potential impact of any changes in the floral assemblage when interpreting sedimentary n-alkane distributions and δ2Halk records.Bailey, S.E., Hublin, J.-J., Antón, S.C., 2019. Rare dental trait provides morphological evidence of archaic introgression in Asian fossil record. Proceedings of the National Academy of Sciences 116, 14806-14807. recently described Denisovan hemimandible from Xiahe, China [F. Chen et al., (2019) Nature 569, 409–412], possesses an unusual dental feature: a 3-rooted lower second molar. A survey of the clinical and bioarchaeological literature demonstrates that the 3-rooted lower molar is rare (less than 3.5% occurrence) in non-Asian Homo sapiens. In contrast, its presence in Asian-derived populations can exceed 40% in China and the New World. It has long been thought that the prevalence of 3-rooted lower molars in Asia is a relatively late acquisition occurring well after the origin and dispersal of H. sapiens. However, the presence of a 3-rooted lower second molar in this 160,000-y-old fossil hominin suggests greater antiquity for the trait. Importantly, it also provides morphological evidence of a strong link between archaic and recent Asian H. sapiens populations. This link provides compelling evidence that modern Asian lineages acquired the 3-rooted lower molar via introgression from Denisovans.Bains, W., Petkowski, J.J., Sousa-Silva, C., Seager, S., 2019. Trivalent phosphorus and phosphines as components of biochemistry in anoxic environments. Astrobiology 19, 885-902. is an essential element for all life on Earth, yet trivalent phosphorus (e.g., in phosphines) appears to be almost completely absent from biology. Instead phosphorus is utilized by life almost exclusively as phosphate, apart from a small contingent of other pentavalent phosphorus compounds containing structurally similar chemical groups. In this work, we address four previously stated arguments as to why life does not explore trivalent phosphorus: (1) precedent (lack of confirmed instances of trivalent phosphorus in biochemicals suggests that life does not have the means to exploit this chemistry), (2) thermodynamic limitations (synthesizing trivalent phosphorus compounds is too energetically costly), (3) stability (phosphines are too reactive and readily oxidize in an oxygen (O2)-rich atmosphere), and (4) toxicity (the trivalent phosphorus compounds are broadly toxic). We argue that the first two of these arguments are invalid, and the third and fourth arguments only apply to the O2-rich environment of modern Earth. Specifically, both the reactivity and toxicity of phosphines are specific to aerobic life and strictly dependent on O2-rich environment. We postulate that anaerobic life persisting in anoxic (O2-free) environments may exploit trivalent phosphorus chemistry much more extensively. We review the production of trivalent phosphorus compounds by anaerobic organisms, including phosphine gas and an alkyl phosphine, phospholane. We suggest that the failure to find more such compounds in modern terrestrial life may be a result of the strong bias of the search for natural products toward aerobic organisms. We postulate that a more thorough identification of metabolites of the anaerobic biosphere could reveal many more trivalent phosphorus compounds. We conclude with a discussion of the implications of our work for the origin and early evolution of life, and suggest that trivalent phosphorus compounds could be valuable markers for both extraterrestrial life and the Shadow Biosphere on Earth.Bannister, M.T., Bhandare, A., Dybczyński, P.A., Fitzsimmons, A., Guilbert-Lepoutre, A., Jedicke, R., Knight, M.M., Meech, K.J., McNeill, A., Pfalzner, S., Raymond, S.N., Snodgrass, C., Trilling, D.E., Ye, Q., The ‘Oumuamua, I.T., 2019. The natural history of ‘Oumuamua. Nature Astronomy 3, 594-602. discovery of the first interstellar object passing through the Solar System, 1I/2017 U1 (‘Oumuamua), provoked intense and continuing interest from the scientific community and the general public. The faintness of ‘Oumuamua, together with the limited time window within which observations were possible, constrained the information available on its dynamics and physical state. Here we review our knowledge and find that in all cases, the observations are consistent with a purely natural origin for ‘Oumuamua. We discuss how the observed characteristics of ‘Oumuamua are explained by our extensive knowledge of natural minor bodies in our Solar System and our current knowledge of the evolution of planetary systems. We highlight several areas requiring further investigation.Bate, B.B., Ozumba, M.B., Ndip, E.A., S Eyinla, D., 2019. A review of the geology of the Rio Del Rey Basin, offshore Cameroon. Journal of Petroleum & Environmental Biotechnology 10, D0I: 10.4172/2157-7463.1000389. review of the tectonic evolution, stratigraphic and structural framework, petroleum systems and hydrocarbon potential of the offshore portion of Rio Del Rey (RDR) Basin in Cameroon is presented in this paper. The RDR basin is a passive margin basin present in the Gulf of Guinea and it is located southeast of Niger Delta over an area of about 7,000 km2 offshore. Its stratigraphic components, like those of Niger Delta, comprise of a diachronous succession of prodelta shales (Akata Formation), overlain by delta front sands and shales (Agbada Formation), in turn, overlain by fluvial sands (Benin Formation). The age of this basin ranges from Eocene to Recent and it consists of four structural provinces namely; the growth fault province in the north, the Cretaceous Onshore province in the southeast, the Shale Ridge province in the southwest, and the Delta Toe-thrust in the south-central region. The RDR Basin features three stages of tectonic development: Pre-rift phase (Late Proterozoic to Late Jurassic); Syn-rift phase (Late Jurassic to Early Cretaceous) and Post-rift phase (Late Cretaceous to Holocene). It presently stands out as the major contributor of the petroleum in the country.Becker-Kerber, B., da Silva, F.R., Amorim, K.B., Pacheco, M.L.A.F., Leme, J.d.M., 2019. Putting the cart before the horse: An example of how the lack of taphonomical approaches can mislead paleobiological inferences for the late Ediacaran. Precambrian Research 332, 105385. arrival of animals with hard parts at the end of the Ediacaran Period was an important evolutionary innovation. Biomineralized structures serve a number of biological functions and pose environmental challenges. Those same hard parts that once played a role in living organisms also affect their postmortem histories. Taphonomic scenarios may create biases that can impact perceptions on the systematic, morphological, biostratigraphic, and paleogeographic patterns in the fossil record. This is well exemplified by the taxonomic controversies regarding Cloudina, the most geographically widespread and abundant shelly fossil of the uppermost Ediacaran. In this study, we discuss new taphonomic data on Cloudina-bearing strata deposits from the Tamengo Formation (Corumbá Group, Brazil) and how influential this taphonomy is on a robust taxonomy of this fossil. Our observations suggest that allochthonous Cloudina deposits from the Tamengo Formation present evidence of taphonomic influences on the transporting/reworking of fragmentation and disarticulation of Cloudina tubes. Differences in size distributions between some of the localities have demonstrated that this trait is not reliable for defining or synonymizing species of Cloudina, and these differences probably reflect a myriad of taphonomic and paleobiological phenomena. Moreover, in some outcrops of the Tamengo Formation, shell walls are usually poorly preserved due to plastic deformations and diagenetic dissolution/recrystallization processes, which conceal morphological diagnostic features used in Cloudina taxonomy. Similar taphonomic biases may be of equal importance to the taxonomy of Cloudina preserved in other upper Ediacaran carbonates. Hence, earlier claims in favor of the synonymization of Cloudina species from the Tamengo Formation cannot currently be justified.Belt, S.T., Smik, L., K?seo?lu, D., Knies, J., Husum, K., 2019. A novel biomarker-based proxy for the spring phytoplankton bloom in Arctic and sub-arctic settings – HBI T25. Earth and Planetary Science Letters 523, 115703. spring phytoplankton bloom is a characteristic feature of mid-high latitudes in modern times, but can be challenging to identify in palaeo records. In the current study, we investigated the absolute and relative distributions of two diatom-derived tri-unsaturated highly branched isoprenoid (HBI) lipids, at least one of which has previously been suggested to be a possible proxy for the productive region of the marginal ice zone (MIZ) in the Polar Regions. Based on a comparison of their distributions in surface sediments from the Barents Sea and neighbouring regions with a range of oceanographic parameters, we identify, via principal component analysis, a strong association between the relative proportion of the two HBIs and satellite-derived spring chlorophyll a (chl a) concentration. Further, based on agglomerative hierarchical clustering, we identify two clusters of HBI biomarker ratios and spring chl a together with a potential threshold biomarker ratio (termed HBI TR25) for the spring phytoplankton bloom. A modified version of HBI TR25 (i.e. HBI T25) provides a potentially more straightforward binary measure of the spring phytoplankton bloom. Analysis of HBI TR25 and HBI T25 values in a series of short (spanning recent centuries) and long (Holocene) sediment cores from the region provides an initial evaluation of the applicability of this novel proxy in the palaeo record. Outcomes are mainly consistent with the findings from the surface sediments and with other proxy-based reconstructions, including estimates of past sea ice cover, which is well-known to influence primary production in the region. Indeed, we suggest that the new HBI T25 phytoplankton bloom proxy may also represent an important new tool for characterising the MIZ in palaeo records, especially when used alongside well-established sea ice proxies, such as IP25 and PIP25. Despite the largely empirical nature of the study, we also provide a possible explanation for the observed biomarker ratio-chl a relationship. Thus, a previous laboratory investigation showed that the distributions of the same two HBIs analysed herein in their likely source (viz. Rhizosolenia setigera) was strongly influenced by culture temperature and growth rate. Confirmation of the generality of our findings and of the causal relationship between HBI T25 and the spring phytoplankton bloom will, however, require further laboratory- and field-based studies in the future.Bengtson, S.A., Meissner, K.J., Menviel, L., Sisson, S.A., Wilkin, J., 2019. Evaluating the extent of North Atlantic deep water and the mean Atlantic δ13C from statistical reconstructions. Paleoceanography and Paleoclimatology 34, 1022-1036. δ13C is often used to infer past changes in ocean circulation, though the interpretation of this proxy is difficult due to data scarcity and uncertainties. We present two methods for reconstructing the δ13C signal of North Atlantic Deep Water (NADW) and Antarctic Bottom Water and calculating the average oceanic δ13C values for the Atlantic Ocean based on δ13C from benthic foraminifera. The two simple statistical models are described and tested for the Holocene and the Last Glacial Maximum. The first statistical model consists of regressions of the δ13C data, which vary quadratically with depth and linearly with latitude. It differentiates between two regions, one for NADW and another for Antarctic Bottom Water. The second method consists of a hyperbolic tangent regression, which is bound asymptotically by the water mass source region averages (end‐members). To test the robustness of the statistical models, two isotope‐enabled climate models, the UVic ESCM and LOVECLIM, are sampled randomly, generating “pseudoproxies.” These are then used for testing the accuracy of the statistical models against the complete climate model δ13C outputs. We quantitatively compare the average δ13C and NADW depth against the original climate model outputs. We find that both statistical approaches are robust, regardless of the spatial distribution of the pseudoproxies, with the quadratic approach better able to capture the shape of NADW δ13C signal. Hence, this method can potentially be applied to different δ13C data sets to evaluate past changes in NADW.Benison, K.C., 2019. How to search for life in martian chemical sediments and their fluid and solid inclusions using petrographic and spectroscopic methods. Frontiers in Environmental Science 7, 108. doi: 10.3389/fenvs.2019.00108. resources and efforts have been employed in the search for life on Mars. Satellites, landers, and rovers have tested atmospheric gases, general sediment and rock compositions, and images of Mars surface in an effort to detect biosignatures left by any possible modern or ancient life. Chloride and sulfate minerals suggestive of past acid saline lakes have been found on Mars. In some terrestrial acid brine environments, these minerals trap microorganisms and organic compounds and preserve them for long geologic time periods within fluid inclusions and as solid inclusions. Some cells remain viable, especially in the isolated, microscopic aqueous environments of fluid inclusions. Fluid inclusions in these same saline minerals on Mars have yet to be examined. This paper describes petrographic and geochemical methods that have been used recently to detect and make general identifications of microorganisms and organic compounds preserved in modern and Permian Mars-analog acid saline lake halite and gypsum. It then makes recommendations for how martian chemical sediments could be examined for these biosignatures, both by rovers and in returned samples. This new protocol for the examination of martian chemical sediments and sedimentary rocks may provide the best way to identify any preserved biosignatures on Mars.Benítez, J.J., Guzman-Puyol, S., Domínguez, E., Heredia, A., Heredia-Guerrero, J.A., 2019. Applications and potentialities of Atomic Force Microscopy in fossil and extant plant cuticle characterization. Review of Palaeobotany and Palynology 268, 125-132. Force Microscopy (AFM) is a versatile technique of surface characterization, providing accurate information about the topography and other wide variety of magnitudes at submicron scale. It is extensively utilized in materials science, but its use in other disciplines such as paleobotany is infrequent. In this review, we introduce the main concepts of AFM to paleobotanists, comparing the characteristics of this technique to common electronic and optical microscopies. Then, main works with extant plants, in particular plant cuticles, are described. Finally, realistic applications with fossils are reviewed and their potential use in the characterization of plant fossils discussed. AFM is proposed as a complementary technique to common microscopies to characterize plant cuticle fine details at nanoscale.Besseling, M.A., Hopmans, E.C., Koenen, M., van der Meer, M.T.J., Vreugdenhil, S., Schouten, S., Sinninghe Damsté, J.S., Villanueva, L., 2019. Depth-related differences in archaeal populations impact the isoprenoid tetraether lipid composition of the Mediterranean Sea water column. Organic Geochemistry 135, 16-31. are one of the most abundant groups of Archaea in the marine water column. Their membrane consists of isoprenoid glycerol dibiphytanyl glycerol tetraethers (GDGTs) which are applied in the widely used TEX86 proxy to reconstruct past sea surface temperatures (SSTs). However, in some specific marine systems, such as the Mediterranean Sea, core-top TEX86-derived temperatures do not seem to reflect annual mean SSTs. This has been attributed to contributions of deep-water dwelling Thaumarchaeota. Here, we investigate the potential causes of this bias by studying both the archaeal diversity as well as the intact polar lipid (IPL) GDGT composition in the Mediterranean water column by a combined 16S rRNA gene amplicon sequencing and a lipidomic approach on suspended particulate matter (SPM) at different water depths. The archaeal distribution showed a dominance of archaea other than Thaumarchaeota, i.e. Marine Euryarchaeota group II and III in the upper epipelagic waters (0–100?m deep), while Thaumarchaeota (Marine group I; MGI) dominated the subsurface and the deeper waters. This shift in the archaeal community composition coincided with a decrease in IPL GDGT-0 and increase of IPL crenarchaeol. The ratio of GDGT-2/GDGT-3 increased with water depth, but values were lower than observed in deep marine waters of some other regions. The increase of the GDGT-2/GDGT-3 ratio coincided with the high relative abundance of deep-water MGI, which may be linked to the high temperature and salinity found in specific water masses of the Mediterranean Sea. We conclude that these particularities of the Mediterranean Sea are responsible for the overestimated SST based on TEX86.Bhatt, C.R., Jain, J.C., Edenborn, H.M., McIntyre, D.L., 2019. Mineral carbonate dissolution with increasing CO2 pressure measured by underwater laser induced breakdown spectroscopy and its application in carbon sequestration. Talanta 205, 120170. this study, the ability of laser-induced breakdown spectroscopy (LIBS) to measure the in situ aqueous dissolution of various mineral carbonates with increasing CO2 pressure was examined. Dissolution experiments included four geologically common mineral carbonates (CaCO3, MgCO3, MnCO3, SrCO3) and the CO2 pressure ranged from ambient to 250?bar. The ensuing plasma emission was spectrally analyzed, and the intensities of Ca, Mg, Mn, and Sr emission lines were used to monitor the respective metal cations released to the aqueous solution. The strong emission lines of Ca (Ca II 393.36, Ca II 396.84, Ca I 422.67?nm), Mg (unresolved magnesium doublet: Mg I 383.230, Mg I 383.829?nm), Mn (unresolved manganese triplet: Mn I 403.076, Mn I 403.307, Mn I 403.449?nm), and Sr (Sr II 407.77, Sr II 421.55, Sr I 460.73?nm) were identified in the spectra. The amounts of metals released from their respective carbonates were estimated at different time intervals following the CO2 injection (5?m, 1, 2, 3, 4, 24?h) and at different pressures (50, 100, 150, 200, 250?bar) using calibration models developed at corresponding pressure settings. The results demonstrated that the pressure-induced dissolution of all carbonates was consistent with their expected and selective pH-dependent solubility. The dissolution rate of CaCO3, MgCO3, and SrCO3 was found to be higher than that of MnCO3. The dissolution of constituents in a Mt. Simon sandstone associated with a deep saline reservoir at elevated CO2 pressure was also studied and Ca release was quantified. The results demonstrated that real-time monitoring of carbonate dissolution by LIBS may provide a useful indirect detection system indicative of CO2 leakage from geologic carbon storage sites.Bidja Abena, M.T., Li, T., Shah, M.N., Zhong, W., 2019. Biodegradation of total petroleum hydrocarbons (TPH) in highly contaminated soils by natural attenuation and bioaugmentation. Chemosphere 234, 864-874. is an emerging and sustainable technique that can either occur naturally or be enhanced by introducing nutrients or bacteria able to degrade specific contaminants. In this study, the efficiencies of natural attenuation with nutrients, and bioaugmentation with nutrients and a consortium of five exogenous bacteria, were evaluated for total petroleum hydrocarbon (TPH) degradation in five highly contaminated soils from China, and Kuwait. The bioaugmentation treatment exhibited better efficiencies than the natural attenuation, and reached 48.10% of TPH degradation with a half-life of 41.76?d. The addition of exogenous bacteria also increased the removal of TPH in the highest contaminated soil sample. The concentration of TPH in that soil was reduced from 236, 500?mg?kg?1 of dry soil to 176, 566?mg?kg?1 of dry soil in 40?d, which was equivalent to 25.4% degradation of TPH. The degradation rate (1501.8?mg?kg?1d?1 of TPH) was higher than those reported in previous studies with a lower concentration of TPH. The bioaugmented strains could withstand high concentrations of TPH and thrive in five different types of soils. Consequently, these strains can be used to remediate soils that are heavily contaminated with petroleum hydrocarbons.Bishop, B.A., Flynn, S.L., Warchola, T.J., Alam, M.S., Robbins, L.J., Liu, Y., Owttrim, G.W., Alessi, D.S., Konhauser, K.O., 2019. Adsorption of biologically critical trace elements to the marine cyanobacterium Synechococcus sp. PCC 7002: Implications for marine trace metal cycling. Chemical Geology 525, 28-36. bacterial plankton play a key role in elemental cycling through their ability to bind, assimilate, metabolize, and modify the redox state of trace metals in seawater. Of those processes, arguably the least studied are the mechanisms underpinning trace metal adsorption to planktonic marine bacteria, despite a plethora of literature pertaining to terrestrial species. Recently, Liu et al. (2015) demonstrated that the marine cyanobacterium Synechococcus sp. PCC 7002 has the capacity to remove appreciable amounts of Cd2+, a proxy for other divalent cations, from seawater by adsorption. In this study, we build on that work and employ a surface complexation modelling (SCM) approach using titration and pH adsorption edge experiments to calculate the thermodynamic binding constants of four bioessential transition metals (Co, Ni, Cu, Zn) to Synechococcus in simulated seawater. Based on the titration results, the major functional groups involved in metal binding were carboxyl groups with a pKa of 5.59 and phosphoryl groups with a pKa of 7.61. Metal adsorption experiments indicate that Synechococcus can bind considerable concentrations of Zn, Cu, Ni, and Co at pH?8. When all four metals are simultaneously added to solution, the same adsorption pattern of Zn?>?Cu?>?Ni?>?Co is maintained, and accurately predicted by the SCM. Based on average marine cell densities and turnover rates of Synechococcus cells in the photic zone, we calculate that Synechococcus, in the absence of competing ligands such as dissolved organic matter (DOM), has the theoretical capacity to remove nearly all of the free metal cations from seawater. These observations highlight the surface reactivity of marine cyanobacteria as a potentially important vector for the transfer of dissolved metals from the photic zone to deeper waters or the seafloor in modernoceans, but they also have implications for the Precambrian oceans as sinking cyanobacteria could have acted as an exit channel for trace elements into ancient sediments including banded iron formations (BIF).Blazevic, A., Albu, M., Mitsche, S., Rittmann, S.K.-M.R., Habler, G., Milojevic, T., 2019. Biotransformation of scheelite CaWO4 by the extreme thermoacidophile Metallosphaera sedula: Tungsten–microbial interface. Frontiers in Microbiology 10, 1492. doi: 10.3389/fmicb.2019.01492. tungsten-microbial interactions and microbial bioprocessing of tungsten ores, which are still underexplored, are the focus of the current study. Here we show that the biotransformation of tungsten mineral scheelite performed by the extreme thermoacidophile Metallosphaera sedula leads to the breakage of scheelite structure and subsequent tungsten solubilization. Total soluble tungsten is significantly higher in cultures containing M. sedula grown on scheelite than the abiotic control, indicating active bioleaching. Advanced analytical electron microscopy was used in order to achieve nanoscale resolution ultrastructural studies of M. sedula grown on tungsten bearing scheelite. In particular, we describe that M. sedula mediated the biotransformation of scheelite, which was accompanied by the release of tungsten into solution and tungsten biomineralization of the cell surface. Furthermore, we observed intracellular incorporation of redox heterogenous Mn- and Fe-containing nano-clusters. Our results highlight unique metallophilic life in hostile environments extending the knowledge of tungsten biogeochemistry. Based on these findings biohydrometallurgical processing of tungsten ores can be further explored. Importantly, biogenic tungsten carbide-like nanolayers described herein are potential targets for developing nanomaterial biotechnology.Blumenthal, S.A., Cerling, T.E., Smiley, T.M., Badgley, C.E., Plummer, T.W., 2019. Isotopic records of climate seasonality in equid teeth. Geochimica et Cosmochimica Acta 260, 329-348. investigate how oxygen isotopes in equid teeth can be used as a record of seasonality. First, we use in situ laser ablation and conventional microsampling techniques to understand time-averaging of environmental signals in intra-tooth isotope profiles in modern feral horse teeth (n?=?5) from Mongolia, where there is a large seasonal gradient in the oxygen isotopic composition of precipitation. We demonstrate that laser ablation can be used to sample inner, middle, and outer enamel layers in large mammalian herbivore teeth. The inner enamel layer records less attenuated isotopic signals than other layers, as predicted by the mineralization patterns, but intra-tooth signal amplitude is similar for laser and conventional sampling methods. Second, we use modern zebra teeth (n?=?21) collected in eastern Africa to evaluate how intra-tooth oxygen isotope variation relates to rainfall patterns in the tropics. We show that the intra-tooth isotopic range increases with intra-annual precipitation isotopic range, which in turn relates to aridity in the equatorial bimodal rainfall region but is influenced by other hydroclimate processes in the region as a whole. Finally, we address isotopic seasonality during the Early Pleistocene in eastern Africa using oxygen isotopes in fossil equid teeth from southwestern Kenya (n = 11) and northern Tanzania (n = 5). We find variable isotopic seasonality in the past, similar to present-day eastern Africa, consistent with the notion that hominins and other mammals were able to accommodate environmental variability on intra-annual scales in addition to well-documented orbital cycles.Bociu, I., Shin, B., Wells, W.B., Kostka, J.E., Konstantinidis, K.T., Huettel, M., 2019. Decomposition of sediment-oil-agglomerates in a Gulf of Mexico sandy beach. Scientific Reports 9, 10071. (SOA) are one of the most common forms of contamination impacting shores after a major oil spill; and following the Deepwater Horizon (DWH) accident, large numbers of SOAs were buried in the sandy beaches of the northeastern Gulf of Mexico. SOAs provide a source of toxic oil compounds, and although SOAs can persist for many years, their long-term fate was unknown. Here we report the results of a 3-year in-situ experiment that quantified the degradation of standardized SOAs buried in the upper 50?cm of a North Florida sandy beach. Time series of hydrocarbon mass, carbon content, n-alkanes, PAHs, and fluorescence indicate that the decomposition of golf-ball-size DWH-SOAs embedded in beach sand takes at least 32 years, while SOA degradation without sediment contact would require more than 100 years. SOA alkane and PAH decay rates within the sediment were similar to those at the beach surface. The porous structure of the SOAs kept their cores oxygen-replete. The results reveal that SOAs buried deep in beach sands can be decomposed through relatively rapid aerobic microbial oil degradation in the tidally ventilated permeable beach sand, emphasizing the role of the sandy beach as an aerobic biocatalytical reactor at the land-ocean interface.Bop, C.T., Batista-Romero, F.A., Faure, A., Quintas-Sánchez, E., Dawes, R., Lique, F., 2019. Isomerism effects in the collisional excitation of cyanoacetylene by molecular hydrogen. ACS Earth and Space Chemistry 3, 1151-1157. excitation of the interstellar HC2NC and HNC3 molecules, two isomers of HC3N, induced by collisions with H2 is investigated at low collision energy using a quantum time-independent approach. The scattering calculations are based on new high-level ab initio four-dimensional (4D) potential energy surfaces (PESs) computed at the explicitly correlated coupled cluster with single, double, and perturbative triple excitations [CCSD(T)-F12b] level of theory. The method of interpolating moving least squares (IMLS) was used to construct 4D analytical PESs. Rotationally inelastic cross sections among the low-lying rotational levels of HC2NC and HNC3 were obtained using a pure quantum close-coupling approach for total energies up to ～100 cm–1. The corresponding thermal rate coefficients were computed for temperatures ranging from 1 to 20 K. Propensity rules in favor of even Δj1 transitions were found for both HC2NC and HNC3 in collisions with para-H2 (j2 = 0), with j1 being the rotational level of HC2NC and HNC3 molecules. The new rate coefficients were compared to previously published HC3N–para-H2 (j2 = 0) rate coefficients. As expected, differences were found, especially for the rate coefficients corresponding to Δj1 = 1 transitions. Such a comparison confirms the importance of having specific collisional data for the different isomers of a molecule. The new rate coefficients will be crucial to improve the estimation of the HC3N/HC2NC/HNC3 abundance ratio in the interstellar medium.Borrok, D.M., Yang, W., Wei, M., Mokhtari, M., 2019. Heterogeneity of the mineralogy and organic content of the Tuscaloosa Marine Shale. Marine and Petroleum Geology 109, 717-731. unconventional clay-rich oil and gas reservoirs are characterized by fine-scale heterogeneity that is challenging to characterize and predict at larger scales. This is particularly problematic in emerging shale plays with limited shared knowledge such as the Tuscaloosa Marine Shale (TMS). The TMS is located within the Central U.S. Gulf Coast region and contains an estimated 7 billion barrels of potentially recoverable oil. In this study we synthesized and interpreted newly available mineralogical and organic geochemical data from 11 wells located in the currently producing area of the TMS. The data are extremely heterogeneous within individual wells, but generally suggest that the basal region of the TMS within the producing region is characterized by higher concentrations of calcite and TOC relative to other areas of the TMS. Data from an ～18?m section near the base of the TMS (including samples from all 11 wells) averaged 1.65?wt% TOC, 22.8?wt% quartz, 17.2?wt% calcite, 16.2?wt% kaolinite, 14.1?wt% illite, 11.8?wt% smecite, 5.7?wt% chlorite, 3.9?wt% plagioclase, and 4.4?wt% pyrite. Kerogen in this region is a mixture of Type II and Type III and Tmax and vitrinite reflectance data suggest that samples from most wells are within the oil and wet gas generation window. Comparisons to previous investigations of the TMS show that most studies are in reasonable agreement only at the largest scales of observation and break down at smaller scales such that the concentrations of minerals and organic matter reported depend largely on the scale and locations of the investigation and the sampling density. Hence, the best approach for quantifying, describing, and ultimately predicting the heterogeneous physical and chemical properties within TMS may be to rely upon statistically-based comparisons of groups of data such that probability distributions of these groups can be generated that vary with the changing stratigraphy and depositional environments.Brailsford, F.L., Glanville, H.C., Golyshin, P.N., Marshall, M.R., Lloyd, C.E., Johnes, P.J., Jones, D.L., 2019. Nutrient enrichment induces a shift in dissolved organic carbon (DOC) metabolism in oligotrophic freshwater sediments. Science of The Total Environment 690, 1131-1139. organic carbon (DOC) turnover in aquatic environments is modulated by the presence of other key macronutrients, including nitrogen (N) and phosphorus (P). The ratio of these nutrients directly affects the rates of microbial growth and nutrient processing in the natural environment. The aim of this study was to investigate how labile DOC metabolism responds to changes in nutrient stoichiometry using 14C tracers in conjunction with untargeted analysis of the primary metabolome in upland peat river sediments. N addition led to an increase in 14C-glucose uptake, indicating that the sediments were likely to be primarily N limited. The mineralisation of glucose to 14CO2 reduced following N addition, indicating that nutrient addition induced shifts in internal carbon (C) partitioning and microbial C use efficiency (CUE). This is directly supported by the metabolomic profile data which identified significant differences in 22 known metabolites (34% of the total) and 30 unknown metabolites (16% of the total) upon the addition of either N or P. 14C-glucose addition increased the production of organic acids known to be involved in mineral P dissolution (e.g. gluconic acid, malic acid). Conversely, when N was not added, the addition of glucose led to the production of the sugar alcohols, mannitol and sorbitol, which are well known microbial C storage compounds. P addition resulted in increased levels of several amino acids (e.g. alanine, glycine) which may reflect greater rates of microbial growth or the P requirement for coenzymes required for amino acid synthesis. We conclude that inorganic nutrient enrichment in addition to labile C inputs has the potential to substantially alter in-stream biogeochemical cycling in oligotrophic freshwaters.Braukmüller, N., Wombacher, F., Funk, C., Münker, C., 2019. Earth’s volatile element depletion pattern inherited from a carbonaceous chondrite-like source. Nature Geoscience 12, 564-568.’s volatile element abundances (for example, sulfur, zinc, indium and lead) provide constraints on fundamental processes, such as planetary accretion, differentiation and the delivery of volatile species, like water, which contributed to Earth becoming a habitable planet. The composition of the silicate Earth suggests a chemical affinity but isotopic disparity to carbonaceous chondrites—meteorites that record the early element fractionations in the protoplanetary disk. However, the volatile element depletion pattern of the silicate Earth is obscured by core formation. Another key problem is the overabundance of indium, which could not be reconciled with any known chondrite group. Here we complement recently published volatile element abundances for carbonaceous chondrites with high-precision sulfur, selenium and tellurium data. We show that both Earth and carbonaceous chondrites exhibit a unique hockey stick volatile element depletion pattern in which volatile elements with low condensation temperatures (750–500?K) are unfractionated from each other. This abundance plateau accounts for the apparent overabundance of indium in the silicate Earth without the need of exotic building materials or vaporization from precursors or during the Moon-forming impact and suggests the accretion of 10–15?wt% CI-like material before core formation ceased. Finally, more accurate estimates of volatile element abundances in the core and bulk Earth can now be provided.Brewer, A., Chang, E., Park, D.M., Kou, T., Li, Y., Lammers, L.N., Jiao, Y., 2019. Recovery of rare earth elements from geothermal fluids through bacterial cell surface adsorption. Environmental Science & Technology 53, 7714-7723. increasing demand for rare earth elements (REEs) in the modern economy motivates the development of novel strategies for cost-effective REE recovery from nontraditional feedstocks. We previously engineered E. coli to express lanthanide binding tags on the cell surface, which increased the REE biosorption capacity and selectivity. Here we examined how REE adsorption by the engineered E. coli is affected by various geochemical factors relevant to geothermal fluids, including total dissolved solids (TDS), temperature, pH, and the presence of specific competing metals. REE biosorption is robust to TDS, with high REE recovery efficiency and selectivity observed with TDS as high as 165,000 ppm. Among several metals tested, U, Al, and Pb were found to be the most competitive, causing >25% reduction in REE biosorption when present at concentrations ～3- to 11-fold higher than the REEs. Optimal REE biosorption occurred between pH 5–6, and sorption capacity was reduced by ～65% at pH 2. REE recovery efficiency and selectivity increased as a function of temperature up to ～70 °C due to the thermodynamic properties of metal complexation on the bacterial surface. Together, these data define the optimal and boundary conditions for biosorption and demonstrate its potential utility for selective REE recovery from geofluids.Brolly, C., Parnell, J., Bowden, S., 2019. Surface mineral crusts: a potential strategy for sampling for evidence of life on Mars. International Journal of Astrobiology 18, 91-101. mineral crusts on Earth are highly diverse and usually, contain microbial life. Crusts constitute an attractive target to search for life: they require water for their formation, they efficiently entrap organic matter and are relatively easy to sample and process. They hold a record of life in the form of microbial remains, biomolecules and carbon isotope composition. A miniaturized Raman spectrometer is included in the ExoMars 2020 payload as it is sensitive to a range of photosynthetic pigments. Samples from the Haughton Impact Structure, Canadian High Arctic and others, shows the preservation of pigments in a range of crust types, especially supra-permafrost carbonate crusts and cryptogamic crusts. The Raman spectral signatures of these crusts are shown along with biomarker analysis to showcase these techniques prior to the ExoMars 2020 mission. Carotenoids and other photoprotective microbial pigments are identified in the Haughton surface crusts using Raman spectroscopy. Gas chromatography-mass spectrometry analyses show a distribution of fatty acids which are most likely from a cyanobacterial source. The successful demonstration of these analyses in the Haughton Impact structure shows the biosignature of surface mineral crusts can be easily extracted and provides an excellent target for sampling evidence of life on Mars.Br?nnimann, S., Franke, J., Nussbaumer, S.U., Zumbühl, H.J., Steiner, D., Trachsel, M., Hegerl, G.C., Schurer, A., Worni, M., Malik, A., Flückiger, J., Raible, C.C., 2019. Last phase of the Little Ice Age forced by volcanic eruptions. Nature Geoscience 12, 650-656. the first half of the nineteenth century, several large tropical volcanic eruptions occurred within less than three decades. The global climate effects of the 1815 Tambora eruption have been investigated, but those of an eruption in 1808 or 1809 whose source is unknown and the eruptions in the 1820s and 1830s have received less attention. Here we analyse the effect of the sequence of eruptions in observations, global three-dimensional climate field reconstructions and coupled climate model simulations. All the eruptions were followed by substantial drops of summer temperature over the Northern Hemisphere land areas. In addition to the direct radiative effect, which lasts 2–3 years, the simulated ocean–atmosphere heat exchange sustained cooling for several years after these eruptions, which affected the slow components of the climate system. Africa was hit by two decades of drought, global monsoons weakened and the tracks of low-pressure systems over the North Atlantic moved south. The low temperatures and increased precipitation in Europe triggered the last phase of the advance of Alpine glaciers. Only after the 1850s did the transition into the period of anthropogenic warming start. We conclude that the end of the Little Ice Age was marked by the recovery from a sequence of volcanic eruptions, which makes it difficult to define a single pre-industrial baseline.Brovkin, V., Lorenz, S., Raddatz, T., Ilyina, T., Stemmler, I., Toohey, M., Claussen, M., 2019. What was the source of the atmospheric CO2 increase during the Holocene? Biogeosciences 16, 2543-2555. atmospheric CO2 concentration increased by about 20?ppm from 6000?BCE to the pre-industrial period (1850?CE). Several hypotheses have been proposed to explain mechanisms of this CO2 growth based on either ocean or land carbon sources. Here, we apply the Earth system model MPI-ESM-LR for two transient simulations of climate and carbon cycle dynamics during this period. In the first simulation, atmospheric CO2 is prescribed following ice-core CO2 data. In response to the growing atmospheric CO2 concentration, land carbon storage increases until 2000?BCE, stagnates afterwards, and decreases from 1?CE, while the ocean continuously takes CO2 out of the atmosphere after 4000?BCE. This leads CO2 a missing source of 166?Pg of carbon in the ocean–land–atmosphere system by the end of the simulation. In the second experiment, we applied a CO2 nudging technique using surface alkalinity forcing to follow the reconstructed CO2 concentration while keeping the carbon cycle interactive. In that case the ocean is a source of CO2 from 6000 to 2000?BCE due to a decrease in the surface ocean alkalinity. In the prescribed CO2 simulation, surface alkalinity declines as well. However, it is not sufficient to turn the ocean into a CO2 source. The carbonate ion concentration in the deep Atlantic decreases in both the prescribed and the interactive CO2 simulations, while the magnitude of the decrease in the prescribed CO2 experiment is underestimated in comparison with available proxies. As the land serves as a carbon sink until 2000?BCE due to natural carbon cycle processes in both experiments, the missing source of carbon for land and atmosphere can only be attributed to the ocean. Within our model framework, an additional mechanism, such as surface alkalinity decrease, for example due to unaccounted for carbonate accumulation processes on shelves, is required for consistency with ice-core CO2 data. Consequently, our simulations support the hypothesis that the ocean was a source of CO2 until the late Holocene when anthropogenic CO2 sources started to affect atmospheric CO2.Brunk, C.F., Martin, W.F., 2019. Archaeal histone contributions to the origin of eukaryotes. Trends in Microbiology 27, 703-714. eukaryotic lineage arose from bacterial and archaeal cells that underwent a symbiotic merger. At the origin of the eukaryote lineage, the bacterial partner contributed genes, metabolic energy, and the building blocks of the endomembrane system. What did the archaeal partner donate that made the eukaryotic experiment a success? The archaeal partner provided the potential for complex information processing. Archaeal histones were crucial in that regard by providing the basic functional unit with which eukaryotes organize DNA into nucleosomes, exert epigenetic control of gene expression, transcribe genes with CCAAT-box promoters, and a manifest cell cycle with condensed chromosomes. While mitochondrial energy lifted energetic constraints on eukaryotic protein production, histone-based chromatin organization paved the path to eukaryotic genome complexity, a critical hurdle en route to the evolution of complex cells.Buongiorno, J., Herbert, L.C., Wehrmann, L.M., Michaud, A.B., Laufer, K., R?y, H., J?rgensen, B.B., Szynkiewicz, A., Faiia, A., Yeager, K.M., Schindler, K., Lloyd, K.G., 2019. Complex microbial communities drive iron and sulfur cycling in Arctic fjord sediments. Applied and Environmental Microbiology 85, e00949-19.: Glacial retreat is changing biogeochemical cycling in the Arctic, where glacial runoff contributes iron for oceanic shelf primary production. We hypothesize that in Svalbard fjords, microbes catalyze intense iron and sulfur cycling in low-organic-matter sediments. This is because low organic matter limits sulfide generation, allowing iron mobility to the water column instead of precipitation as iron monosulfides. In this study, we tested this with high-depth-resolution 16S rRNA gene libraries in the upper 20?cm at two sites in Van Keulenfjorden, Svalbard. At the site closer to the glaciers, iron-reducing Desulfuromonadales, iron-oxidizing Gallionella and Mariprofundus, and sulfur-oxidizing Thiotrichales and Epsilonproteobacteria were abundant above a 12-cm depth. Below this depth, the relative abundances of sequences for sulfate-reducing Desulfobacteraceae and Desulfobulbaceae increased. At the outer station, the switch from iron-cycling clades to sulfate reducers occurred at shallower depths (～5?cm), corresponding to higher sulfate reduction rates. Relatively labile organic matter (shown by δ13C and C/N ratios) was more abundant at this outer site, and ordination analysis suggested that this affected microbial community structure in surface sediments. Network analysis revealed more correlations between predicted iron- and sulfur-cycling taxa and with uncultured clades proximal to the glacier. Together, these results suggest that complex microbial communities catalyze redox cycling of iron and sulfur, especially closer to the glacier, where sulfate reduction is limited due to low availability of organic matter. Diminished sulfate reduction in upper sediments enables iron to flux into the overlying water, where it may be transported to the shelf.Importance: Glacial runoff is a key source of iron for primary production in the Arctic. In the fjords of the Svalbard archipelago, glacial retreat is predicted to stimulate phytoplankton blooms that were previously restricted to outer margins. Decreased sediment delivery and enhanced primary production have been hypothesized to alter sediment biogeochemistry, wherein any free reduced iron that could potentially be delivered to the shelf will instead become buried with sulfide generated through microbial sulfate reduction. We support this hypothesis with sequencing data that showed increases in the relative abundance of sulfate reducing taxa and sulfate reduction rates with increasing distance from the glaciers in Van Keulenfjorden, Svalbard. Community structure was driven by organic geochemistry, suggesting that enhanced input of organic material will stimulate sulfate reduction in interior fjord sediments as glaciers continue to recede.Busch, A., Han, F., Magill, C.R., 2019. Paleofloral dependence of coal methane sorption capacity. International Journal of Coal Geology 211, 103232. aim of this study is to reveal key physiochemical factors controlling gas sorption in coals during periods of dramatic coal deposition in Earth's history – the Upper Carboniferous (326–299?Ma) and Permian (299–252?Ma). As a starting point we developed a database of about 1000 entries, including coal-specific parameters such as proximate and ultimate analysis, sample origin, and specific surface area. Our study proposes an innovative approach that links emerging, quantitative organic molecular analyses with more established bulk (bio)geochemical techniques as a context for (1) describing gas–coal (i.e., coalbed methane) formations, (2) sweet-spot identification in terms of methane sorption potential. We found that the main controlling parameter is coal age; Permian coals generally adsorb significantly more methane than Carboniferous coals at comparable maturity. This difference is reflected in micropore surface area and oxygen content of the two sets, with Permian having higher values than the corresponding Carboniferous coals. We attribute this difference in Langmuir volume or surface area to the original plant material, expressed through differences in the molecular structures and surface chemistries of the sorption sites which is also clearly reflected in a lower aromaticity for Permian coals. This leads to a more detailed view on the evolution of original plant material from the Carboniferous to Permian age, coinciding with an evolution in plant material, specifically lignite, changes in climatic conditions towards more arid environments, possible changes in water compositions and bacterial activities.Buvignier, A., Peyre-Lavigne, M., Robin, O., Bounouba, M., Patapy, C., Bertron, A., Paul, E., 2019. Influence of dissolved-aluminum concentration on sulfur-oxidizing bacterial activity in the biodeterioration of concrete. Applied and Environmental Microbiology 85, e00302-19.: Several studies undertaken on the biodeterioration of concrete sewer infrastructures have highlighted the better durability of aluminate-based materials. The bacteriostatic effect of aluminum has been suggested to explain the increase in durability of these materials. However, no clear demonstration of the negative effect of aluminum on cell growth has been yet provided in the literature. In the present study, we sought to investigate the inhibitory potential of dissolved aluminum on nonsterile microbial cultures containing sulfur-oxidizing microorganisms. Both kinetic (maximum specific growth rate) and stoichiometric (oxygen consumption yield) parameters describing cells activity were accurately determined by using respirometry measurements coupled with modeled data obtained from fed-batch cultures run for several days at pH below 4 and with increasing total aluminum (Altot) concentrations from 0 to 100?mM. Short-term inhibition was observed for cells poorly acclimated to high salinity. However, inhibition was significantly attenuated for cells grown on mortar substrate. Moreover, after a rapid adaptation, and for an Altot concentration up to 100?mM, both kinetic and stoichiometric growth parameters remained similar to those obtained in control culture conditions where no aluminum was added. This argued in favor of the impact of ionic strength change on the growth of sulfur-oxidizing microorganism rather than an inhibitory effect of dissolved aluminum. Other assumptions must therefore be put forward in order to explain the better durability of cement containing aluminate-based materials in sewer networks. Among these assumptions, the influence of physical or chemical properties of the material (phase reactivity, porosity, etc.) might be proposed.Importance: Biodeterioration of cement infrastructures represents 5 to 20% of observed deteriorations within the sewer network. Such biodeterioration events are mainly due to microbial sulfur-oxidizing activity which produces sulfuric acid able to dissolve cementitious material. Calcium aluminate cement materials are more resistant to biodeterioration compared to the commonly used Portland cement. Several theories have been suggested to describe this resistance, and the bacteriostatic effect of aluminum seems to be the most plausible explanation. However, results reported by the several studies on this exact topic are highly controversial. This present study provides a comprehensive analysis of the influence of dissolved aluminum on growth parameters of long-term cultures of sulfur-oxidizing bacterial consortia sampled from different origins. Kinetic and stoichiometric parameters estimated by respirometry measurements and modeling showed that total dissolved-aluminum concentrations up to 100?mM were not inhibitory, but it is more likely that a sudden increase in the ionic strength affects cell growth. Therefore, it appears that the bacteriostatic effect of aluminum on microbial growth cannot explain the better durability of aluminate based cementitious materials.Calo, C.M., Rizzutto, M.A., Watling, J., Furquim, L., Shock, M.P., Andrello, A.C., Appoloni, C.R., Freitas, F.O., Kistler, L., Zimpel, C.A., Hermenegildo, T., Neves, E.G., Pugliese, F.A., 2019. Study of plant remains from a fluvial shellmound (Monte Castelo, RO, Brazil) using the X-ray MicroCT imaging technique. Journal of Archaeological Science: Reports 26, 101902. work applies the X-ray MicroCT imaging technique to discuss the identification and preservation/disturbance conditions of plant remains from the Monte Castelo archaeological site, in Brazil's southwestern Amazonia. A preliminary hypothesis based on external morphological traits and the presence of typical starch grains, associates these materials to the Poaceae caryopsis. Moreover, based on their well-preserved non-charred aspect, mineralization was considered as a possible in-situ preservation process. Data from the X-ray computed microtomography (MicroCT) analysis showed that the internal anatomy of the samples corresponds to another type of fruit, described as a small drupe sharing characters with some Anacardiaceae fruits. Additionally, all studied specimens contain a number of exogenous organic and inorganic elements suggesting the action of some disturbance processes on the Monte Castelo plant material.Campen, R., Kowalski, J., Lyons, W.B., Tulaczyk, S., Dachwald, B., Pettit, E., Welch, K.A., Mikucki, J.A., 2019. Microbial diversity of an Antarctic subglacial community and high-resolution replicate sampling inform hydrological connectivity in a polar desert. Environmental Microbiology 21, 2290-2306. subglacial environments host microbial ecosystems and are proving to be geochemically and biologically diverse. The Taylor Glacier, Antarctica, periodically expels iron-rich brine through a conduit sourced from a deep subglacial aquifer, creating a dramatic red surface feature known as Blood Falls. We used Illumina MiSeq sequencing to describe the core microbiome of this subglacial brine and identified previously undetected but abundant groups including the candidate bacterial phylum Atribacteria and archaeal phylum Pacearchaeota. Our work represents the first microbial characterization of samples collected from within a glacier using a melt probe, and the only Antarctic subglacial aquatic environment that, to date, has been sampled twice. A comparative analysis showed the brine community to be stable at the operational taxonomic unit level of 99% identity over a decade. Higher resolution sequencing enabled deconvolution of the microbiome of subglacial brine from mixtures of materials collected at the glacier surface. Diversity patterns between this brine and samples from the surrounding landscape provide insight into the hydrological connectivity of subglacial fluids to the surface polar desert environment. Understanding subice brines collected on the surfaces of thick ice covers has implications for analyses of expelled materials that may be sampled on icy extraterrestrial worlds.Capriotti, A.L., Cavaliere, C., La Barbera, G., Montone, C.M., Piovesana, S., Laganà, A., 2019. Recent applications of magnetic solid-phase extraction for sample preparation. Chromatographia 82, 1251-1274. minireview is dedicated to the discussion of analytical methods based on magnetic solid-phase extraction for the investigation of different analyte classes in complex matrices. Magnetic solid-phase extraction represents one of the most exploited approaches for sample preparation, which benefits from the development of new materials and from the coupling with other purification and clean-up strategies. New materials are continuously described for the isolation and enrichment of a variety of compounds, from small molecules to biologic macromolecules. Such magnetic materials developed for magnetic solid-phase extraction are discussed in this minireview, spanning across different types of materials, from the more traditional magnetic nanoparticles functionalized with polymers, to molecularly imprinted polymers, but also graphene, carbon nanotubes, graphitized carbon black, metal organic frameworks, covalent organic frameworks, composite materials, biopolymers (polydopamine, chitosan), materials from wastes and natural products and the newly introduced knitting aromatic polymers. The magnetic solid-phase extraction methods are collected from the recent literature and organized in sections based on the target analyte classes, which include drugs, endocrine-disrupting compounds, pesticides, polycyclic aromatic hydrocarbons, metals, toxins, peptides, proteins, metabolites and a final chapter dedicated to applications to other common pollutants, contaminants and multiresidue methods. A selection of recent applications and variations of the traditional magnetic solid-phase extraction protocols is discussed for food, environmental and biologic matrices. Finally, the compliance of magnetic solid-phase extraction with the principles of green analytical chemistry is also briefly discussed, with recent examples, indicating the use of waste or sustainable materials, development of green material preparations and reduction of organic solvents as the main strategies for future development of environmentally friendly magnetic solid-phase extraction methods.Carlson, R.W., 2019. Analysis of lunar samples: Implications for planet formation and evolution. Science 365, 240-243. analysis of lunar samples returned to Earth by the Apollo and Luna missions changed our view of the processes involved in planet formation. The data obtained on lunar samples brought to light the importance during planet growth of highly energetic collisions that lead to global-scale melting. This violent birth determines the initial structure and long-term evolution of planets. Once past its formative era, the lunar surface has served as a recorder of more than 4 billion years of interaction with the space environment. The chronologic record of lunar cratering determined from the returned samples underpins age estimates for planetary surfaces throughout the inner Solar System and provides evidence of the dynamic nature of the Solar System during the planet-forming era.Cesar, J., Eiler, J., Dallas, B., Chimiak, L., Grice, K., 2019. Isotope heterogeneity in ethyltoluenes from Australian condensates, and their stable carbon site-specific isotope analysis. Organic Geochemistry 135, 32-37. (LMW) aromatic compounds from petroleum fluids have not been widely studied for fluid-source correlations due to their volatility and their relatively low abundances in source rocks. However, LMW aromatics are important components in fluids, including condensates which lack biomarkers (molecular fossils typically used for correlation studies). Here, we have investigated the distribution of ethyltoluenes (o-ET, m-ET and p-ET; ortho, meta and para, respectively) in fluvial-deltaic condensates which contain relatively high abundances of the meta-isomer. The meta-selectivity found in these petroleum fluids is consistent with a mineral catalytic effect on the molecular distribution of these compounds, as it occurs during the clay-catalyzed synthesis of ethyltoluenes. Isomers differ up to 6‰ in δ13C values. Condensates from the Northern Carnarvon Basin, North West Shelf of Australia (NWS), have been analyzed by compound specific isotope analysis (CSIA) by GC-ir-MS, and site-specific isotope analysis (SSIA) using a Q-Exactive-GC Orbitrap?-based mass spectrometer. The SSIA revealed a 13C enrichment at the methyl end of the ethyl branch of m-ET, following a normal kinetic isotope effect during thermal maturation (cleavage). Continuous development of this first SSIA application will make possible high resolution analysis of light aromatics to outline the evolution of the organic matter to hydrocarbons in petroleum systems.Cesar, J., Grice, K., 2019. Molecular fingerprint from plant biomarkers in Triassic-Jurassic petroleum source rocks from the Dampier sub-Basin, Northwest Shelf of Australia. Marine and Petroleum Geology 110, 189-197. land plant biomarker distributions have been described for Triassic-Jurassic source rocks in the Dampier sub-Basin, Northwest Shelf of Australia. Proxies like the higher plant parameter [HPP?=?retene/(cadalene?+?retene)] cannot be applied to describe palaeoclimate globally; in fact, the HPP showed similar values (～0.8) for Triassic and Jurassic source rocks despite the difference in sea level. The higher plant fingerprint [HPF or relative distribution of retene, cadalene and 6-isopropyl-1-isohexyl-2-methylnaphthalene (ip-iHMN)], however, represents a potential discrimination tool for source rock intervals. Here, we name this proxy as plant fingerprint (PF) since our investigation supports a non-vascular plant origin for ip-iHMN. The most distinctive patterns in the PF are found in the Early Jurassic with a predominance of cadalene (～65%) in an arid climate, and the Middle Jurassic with a predominance of retene (～70%) during a climate recovery under more humid conditions. Petroleum fluids from the Dampier sub-Basin are cadalene-dominated compared to fluids from the Barrow sub-Basin, which are retene-dominated. We emphasise that the present approach has only local implications and the parameters used herein (including the higher plant parameter or HPP) cannot lead to interpretations at a global scale.Chandler, M.R., Mecklenburgh, J., Rutter, E., Lee, P., 2019. Fluid injection experiments in shale at elevated confining pressures: Determination of flaw sizes from mechanical experiments. Journal of Geophysical Research: Solid Earth 124, 5500-5520. Triaxial experiments and direct fluid injection experiments have been conducted at confining pressures up to 100?MPa on Mancos shale, Whitby mudstone, Penrhyn slate, and Pennant sandstone. Experiments were conducted with sample axes lying both parallel and perpendicular to layering in the materials. During triaxial failure Penrhyn slate was stronger for samples with cleavage parallel to maximum principal stress, but the two orientations in the shales displayed similar failure stresses. Initial flaw sizes of around 40??m were calculated from the triaxial data using the wing crack model, with the shales having shorter initial flaws than the nonshales. During direct fluid injection, breakdown was rapid, with no discernible gap between fracture initiation and breakdown. Breakdown pressure increased linearly with confining pressure but was less sensitive to confining pressure than expected from existing models. A fracture mechanics-based model is proposed to determine the initial flaw size responsible for breakdown in injection experiments. Flaw sizes determined in this way agree reasonably with those determined from the triaxial data in the nonshales at low confining pressures. As confining pressure rises, a threshold is reached, above which the fluid injection experiments suggest a lower initial flaw length of around 10??m. This threshold is interpreted as being due to the partial closure of flaws. In the shales an initial flaw length of around 10??m was determined at all confining pressures, agreeing reasonably with those determined through the triaxial experiments.Chaudhary, D.K., Bajagain, R., Jeong, S.-W., Kim, J., 2019. Development of a bacterial consortium comprising oil-degraders and diazotrophic bacteria for elimination of exogenous nitrogen requirement in bioremediation of diesel-contaminated soil. World Journal of Microbiology and Biotechnology 35, 99. purpose of this study was to develop an effective bacterial consortium and determine their ability to overcome nitrogen limitation for the enhanced remediation of diesel-contaminated soils. Towards this, various bacterial consortia were constructed using oil-degrading and nitrogen-fixing microbes. The diesel removal efficiency of various developed consortia was evaluated by delivering the bacterial consortia to the diesel-contaminated soils. The consortium Acinetobacter sp. K-6?+?Rhodococcus sp. Y2-2?+?NH4NO3 resulted in the highest removal (85.3%) of diesel from the contaminated soil. The consortium containing two different oil-degrading microbes (K-6?+?Y2-2) and one nitrogen-fixing microbe Azotobacter vinelandii KCTC 2426 removed 83.1% of the diesel from the soil after 40 days of treatment. The total nitrogen content analysis revealed higher amounts of nitrogen in soil treated with the nitrogen-fixing microbe when compared with that of the soil supplemented with exogenous inorganic nitrogen. The findings in this present study reveal that the consortium containing the nitrogen-fixing microbe degraded similar amounts of diesel to that degraded by the consortium supplemented with exogenous inorganic nitrogen. This suggests that the developed consortium K-6?+?Y2-2?+?KCTC 2426 compensated for the nitrogen limitation and eliminated the need for exogenous nitrogen in bioremediation of diesel-contaminated soils.Chen, Q., Liu, Q., 2019. Bitumen coating on oil sands clay minerals: A review. Energy & Fuels 33, 5933-5943. of bitumen products by mineral solids is an intractable problem in the oil sands industry. Clay minerals with a bitumen coating, a major component of the mineral solids contaminants in bitumen, adversely affect bitumen production in multiple ways: hindering bitumen extraction, hindering dewatering of extraction tailings, stabilizing water-in-bitumen emulsions, lowering the quality of bitumen, and so on. In this review, the recent progresses in understanding these bitumen-coated clay particles are summarized, particularly focusing on the spatial distribution of the bitumen coating on clay surfaces and the effect of such coating on clay behaviors. Here, “bitumen coating” is defined as all types of irreversibly adsorbed organic matter on oil sands clay minerals, including (but not limited to) asphaltenes and humic materials. The patchy nature of this bitumen coating has been proven and visualized in several recent works where different approaches have been used, including quantitative nanomechanical atomic force microscopy, total internal reflection fluorescence microscopy, and electron energy-loss spectroscopy. The presence of a bitumen coating makes the clay particles behave “actively” in bitumen production processes, causing the clays to migrate to bitumen products, i.e., water-extracted bitumen froth and solvent-extracted bitumen. The available methods for removal of fine mineral solids from the bitumen products are described. This review also brings forward the challenges and opportunities for future research regarding the characterization and handling of oil sands clay minerals.Chen, S., Zhou, Y., Liu, H., Yang, J., Wei, Y., Zhang, J., 2019. Synthesis and physicochemical investigation of anionic–nonionic surfactants based on lignin for application in enhanced oil recovery. Energy & Fuels 33, 6247-6257. series of eco-friendly anionic–nonionic surfactant lignin polyether sulfonates (LPES) based on alkali lignin from the paper-making industry was prepared through alkoxylation, allylation, and sulfonation reactions. The chemical structures of synthesized surfactants were determined by an infrared (IR) spectrogram and 1H nuclear magnetic resonance (1H NMR). In order to verify the adaptability of LPES surfactants applied in chemical enhanced oil recovery (EOR), the physicochemical properties including surface tension, salt tolerance, hydrophile lipophile balance (HLB) values, and interfacial tension for LPES surfactants were investigated through experiments. The critical micelle concentration (cmc) of LPES surfactants increased with the growth of ethylene oxide (EO) groups in the molecules, and the corresponding surface tension values were about 32–38 mN/m. Salt tolerance measurements prove that the LPES surfactants have a high tolerance to Na+ and Ca2+, and the HLB measurements demonstrate that the LPES surfactants have excellent emulsifying properties in oil/water (O/W) systems. Compared with Xinjiang crude oil, the LPES surfactants exhibit the desired ability of decreasing the interfacial tension (IFT) of Daqing/Huabei crude oil, which contains more colloid and asphaltene, and the LPES surfactants can reduce the IFT between Daqing (or Huabei) crude oil and brine to the 10–3 mN/m level in the presence of alkali.Chen, X., Hua, L., Wang, Y., Hou, K., Jiang, J., Xie, Y., Li, H., 2019. Fast online two-dimensional analysis of monoterpenes using multi-capillary column high-pressure photoionization time-of-flight mass spectrometry. Chinese Journal of Chromatography 37, 904-910. of the most abundant biological volatile organic compounds (BVOCs) in the atmosphere, monoterpene, is characterized by its short lifetime, low concentration, fast temporal and spatial variations, and wide variety of isomers. In this study, a multi-capillary column (MCC) was combined with high-pressure photoionization time-of-flight mass spectrometry (HPPI-TOF MS) and employed to develop an MCC-HPPI-TOF MS combination instrument as an online two-dimensional gas chromatography-mass spectrometry (GC-MS) method for the rapid qualitative and quantitative analysis of monoterpene isomers. As a result, six monoterpene isomers, α -pinene, β -pinene, α -terpinene, γ -terpinene, 3-carene, and limonene, were successfully isolated in 180 s with limits of detection (LODs) as low as 6 μg/m3 without sample pre-enrichment. This method was successfully applied to the rapid online analysis of monoterpenes released from the branches and leaves of Cedrus atlantica and Sabina chinensis, which shows the capability and potential application of the method for the online detection of complex sample mixtures in environmental monitoring, process analysis, and other fields.Chen, Z., Cui, J., Ren, Z., Jiang, S., Liang, X., Wang, G., Zou, C., 2019. Geochemistry, paleoenvironment and mechanism of organic-matter enrichment in the Lower Silurian Longmaxi Formation shale in the Sichuan Basin, China. Acta Geologica Sinica - English Edition 93, 505-519. investigate the mechanism of the organic‐matter enrichment in the Lower Longmaxi Formation shale, the geochemistry and total organic carbon (TOC) of the Longmaxi Formation black shales in the Jiaoshiba, Zhaotong, and Weiyuan areas of the Sichuan Basin were analyzed. Paleoproductivity proxy parameters (Babio, Siex, and Ni/Al), clastic influx proxies (TiO2 and Ti/Al), redox indices (V/Cr, Ni/Co, V/(V+Ni), and U/Th), and hydrothermal indicators (Fe, Mn, and Y concentrations; Fe/Ti ratio and a Ni‐Zn‐Co diagram) were employed to decipher the paleoenvironment of the Lower Longmaxi Formation shales. TiO2 and Ti/Al indicated low terrigenous detrital influx in all three areas. However, Babio, Siex, and Ni/Al indicated high productivity in the Jiaoshiba area. V/Cr, Ni/Co, and U/Th indicated higher oxygen content with larger fluctuations in the Zhaotong and Weiyuan areas. Fe, Mn, and Y concentrations and the Fe/Ti ratio implied greater active hydrothermal activity in the Weiyuan area. These heterogeneities were considered to be closely related to the paleoenvironment and paleogeography, and the large basement faults that developed during the Chuanzhong paleo‐uplift could have provided vents for deep‐hydrothermal‐fluid upwelling. The redox indices (V/Cr, Ni/Co, and U/Th) and a paleoproductivity proxy (Ni/Al) displayed a significant correlation with the TOC, suggesting that both excellent preservation conditions and high paleoproductivity were the controlling factors for the enrichment of organic matter in the Longmaxi Formation shale. There was no obvious correlation between the clastic influx proxy (Ti/Al) and the TOC due to the extremely low supply of terrigenous debris. The hydrothermal indicator (Fe/Ti) was negatively correlated with the TOC in the Weiyuan area, indicating that hydrothermal activity may have played a negative role in the accumulation of organic matter. This study suggests that the enrichment of organic matter in the Longmaxi Formation marine shale varied according to the paleogeography and sedimentary environment.Chen, Z., Dewing, K., Synnott, D.P., Liu, X., 2019. Correcting Tmax suppression: A numerical model for removing adsorbed heavy oil and bitumen from Upper Ordovician source rocks, Arctic Canada. Energy & Fuels 33, 6234-6246. Rock-Eval 6 dataset of 66 samples from the Cape Phillips Formation in the Canadian Arctic region was studied to investigate source rock characteristics and petroleum generation potential. Bulk geochemical characteristics and thermal decomposition behavior of the samples indicate an initial generation potential close to 700 mg HC/g TOC and show an unusually low onset Tmax temperature for petroleum generation. This led to an examination of possible Tmax suppression due to a large amount of high-molecular-weight heavy oil and bitumen derived from the early breakdown of kerogen in the samples. Application of a numerical method based on kerogen decomposition kinetics allows for the numerical removal of thermal evaporative products of oil and bitumen adsorbed in the sample without requiring additional pyrolysis experiments or solvent extraction treatments of sample replicates. The removal of the adsorbed hydrocarbon from samples increases the Tmax value up to 17 °C. The estimated petroleum in the sorption phase varies from 1 to about 9 mg HC/g rock, depending on the total organic content (TOC) and maturity, and is the main form of the total oil yield in this area. The corrected Tmax–HI cross-plot suggests an onset of petroleum generation around 435 °C of Tmax, consistent with the general consensus for a normal marine source rock in this region. The constructed kinetic model shows a maximum of 75% transformation ratio (TR), and most samples show TR ranging from 10 to 50% in the early oil generation window on Cornwallis Island. This reconstructed source rock thermal decomposition model in a geological time scale indicates the onset of massive petroleum generation at a temperature of 120 °C, and the maximum transformation ratio of 75% corresponds to a temperature of 140 °C over geological time.Cheng, C., Busigny, V., Ader, M., Thomazo, C., Chaduteau, C., Philippot, P., 2019. Nitrogen isotope evidence for stepwise oxygenation of the ocean during the Great Oxidation Event. Geochimica et Cosmochimica Acta 261, 224-247. Earth’s oxygenation represents one of the most important environmental drivers of life’s evolution, with the first rise, known as ‘the Great Oxidation Event’ (GOE), corresponding to unpreceded accumulation of atmospheric O2, changes in the flux of marine nutrients and possibly global glaciations. However, the detailed evolution of the GOE is still debated, as for instance the accumulation trends of oceanic versus atmospheric oxygen and the nature of biogeochemical responses to oxygenation. Here, we combine organic carbon and bulk nitrogen isotope compositions with major element concentrations and iron speciation data of sedimentary rocks recovered from two drill cores (T2 and T3) in the early Paleoproterozoic Turee Creek Group, Western Australia, to track the redox evolution of marine conditions during the GOE. T2 core samples of the Kungarra Formation, which consists of clastic sedimentary rocks overlaid by the glaciogenic Meteorite Bore Member, were deposited ～2.31?Ga ago. T3 core intercepts, from bottom to top, quartzite of the Koolbye Formation, and shales and stromatolitic carbonates of the Kazput Formation, which were deposited around ～2.25?Ga. Samples from T2 show minor variations of δ13Corg (avg. ?34.5?±?1.7‰, n?=?30), with no significant difference between siliciclastic and glaciogenic sedimentary rocks. In contrast, T3 samples display an increase in δ13Corg from ?32.0 to ?24.8‰ (n?=?54) from shales to carbonates. In both T2 and T3 cores, δ13Corg values are inversely correlated with Al2O3, suggesting a strong petrological control on δ13Corg values, inferred here as resulting from variable contributions of detrital organic matter. Bulk N contents are low, from 13.5 to 56.7?ppm and 15.7 to 53.4?ppm in T2 and T3 samples, respectively. The δ15N values show a bimodal distribution, with one mode at +2.6‰ in T2 and another at +8.8‰ in T3, independent from lithological variations. This δ15N values shift between T2 and T3 is interpreted as reflecting a change from dominating N2-fixers to NO3-assimilating organisms. This implies an increase of NO3? availability, and thus of O2 concentration, during the time interval separating the deposition of T2 and T3 sediments. Dissolved NO3? and O2 concentrations of the Turee Creek marine basin are estimated from two models using N isotope data. The dissolved NO3? concentration has an upper limit ranging from 1.91 to 3.04??M, about one order of magnitude below the average value of modern oceans. The lower limit for dissolved oxygen concentration ranges from 1.8 to 4.4??M, which is two orders of magnitude lower than modern oceans. Together with previous studies, the present data place quantitative constraints on the redox changes associated with the Great Oxidation Event and illustrate a stepwise increase of NO3? bioavailability between 2.31 to 2.25?Ga, in relation with increasing O2 level.Cheng, Q., Zhang, M., Li, H., 2019. Anomalous distribution of steranes in deep lacustrine facies low maturity-maturity source rocks and oil of Funing formation in Subei Basin. Journal of Petroleum Science and Engineering 181, 106190. analyses such as pyrolysis, soluble organic matter extraction, group component separation and GC-MS were conducted to 22 source rock samples and 28 crude oil samples from deep lacustrine facies of Funing Formation in Subei Basin. Source rocks stayed at the low maturity-mature stage (Ro:0.58%–0.71%), while crude oil stayed at the mature stage (Rc:0.71%–0.88%). The Pr/Ph values of samples in the research area ranged between 0.16 and 0.62. These samples could be classified as Sterane/Hopane>1 and Sterane/Hopane<1. For all the samples, the C29 Steranes content was high; had inverse “L” distribution in ααα20RC27-ααα20RC28-ααα20RC29 regular sterane; αα20R-Sterane played a dominant role; abundances of ββ- and 20S-Sterane were low. As for samples of Sterane/Hopane>1, G/C30H ranged between 0.63 and 2.56, and the Sterane isomerization was very low. As for samples with Sterane/Hopane<1, G/C30H ranged between 0.04 and 0.46 and the Sterane isomerization was higher than the former. Abnormal distribution of Sterane isomerization was rarely influenced by thermal dynamic effects and sources, but was mainly influenced by the sedimentary environment. A lot of references reported Sterane isomerization with abnormally high abundance under the high-salinity environment. However, the finding obtained by the research that the higher water salinity corresponded to the lower degree of Sterane isomerization was discovered for the first time. The C29 Sterane abundance was high and the C29/C27 regular sterane ratio was constant and would not vary with changes of environmental parameters and biological source parameters. Sterane content was not correlated with tricyclic terpene of algae sources, but was positively correlated with ETR of the aquatic organism source, while it had very good positive correlation with Gammacerane. In addition, samples with the high Sterane content had high abundance in Carotene, C24+alkyl-cyclohexane and C21+isoprenoid alkanes. Through profound analysis and reference survey, it is found that the abnormally high abundance of C29 Sterane of samples in the research area may be correlated with halophilic protozoon in salinized deepwater lakes.Chi, J., Zhang, W., Wang, L., Putnis, C.V., 2019. Direct observations of the occlusion of soil organic matter within calcite. Environmental Science & Technology 53, 8097-8104. soil carbon cycling plays a key role in regulating and stabilizing the earth’s climate change because of soils with amounts of carbon at least three times greater than those of other ecological systems. Soil minerals have also been shown to underlie the persistence of soil organic matter (SOM) through both adsorption and occlusion, but the microscopic mechanisms that control the latter process are poorly understood. Here, using time-resolved in situ atomic force microscopy (AFM) to observe how calcite, a representative mineral in alkaline soils, interacts with humic substances, we show that following adsorption, humic substances are gradually occluded by the advancing steps of spirals on the calcite (1014) face grown in relatively high supersaturated solutions, through the embedment, compression, and closure of humic substance particles into cavities. This occlusion progress is inhibited by phytate at high concentrations (10–100 μM) due to the formation of phytate-Ca precipitates on step edges to prevent the step advancement, whereas phytate at relatively low concentrations (≤1 μM) and oxalate at high concentrations (100 μM) have little effect on this process. These in situ observations may provide new insights into the organo–mineral interaction, resulting in the incorporation of humic substances into minerals with a longer storage time to delay degradation in soils. This will improve our understanding of carbon cycling and immobilization in soil ecological systems.Chia, H.E., Marsh, E.N.G., Biteen, J.S., 2019. Extending fluorescence microscopy into anaerobic environments. Current Opinion in Chemical Biology 51, 98-104. microscopy is a powerful tool for investigating living cells. While widely used fluorescent proteins, such as green fluorescent protein (GFP), have had huge impact in biological imaging because they provide genetically encoded, highly specific labeling, these probes require oxygen to generate fluorescence. This crucial oxidative step has limited the use of GFP-like proteins in anaerobic bacterial systems and restricted live-cell studies of obligate anaerobes and their biology. This review discusses alternative approaches to labeling proteins in anaerobic bacteria that are compatible with live-cell fluorescence microscopy in strict oxygen-free environments. The advantages, disadvantages, and likelihood of successful implementation for each approach are considered to provide context and guide further advances in anaerobic fluorescence labeling.Christ, B., Xu, C., Xu, M., Li, F.-S., Wada, N., Mitchell, A.J., Han, X.-L., Wen, M.-L., Fujita, M., Weng, J.-K., 2019. Repeated evolution of cytochrome P450-mediated spiroketal steroid biosynthesis in plants. Nature Communications 10, 3206. is a spiroketal steroidal natural product extracted from plants and used as the single most important precursor for the world steroid hormone industry. The sporadic occurrences of diosgenin in distantly related plants imply possible independent biosynthetic origins. The characteristic 5,6-spiroketal moiety in diosgenin is reminiscent of the spiroketal moiety present in anthelmintic avermectins isolated from actinomycete bacteria. How plants gained the ability to biosynthesize spiroketal natural products is unknown. Here, we report the diosgenin-biosynthetic pathways in himalayan paris (Paris polyphylla), a monocot medicinal plant with hemostatic and antibacterial properties, and fenugreek (Trigonella foenum–graecum), an eudicot culinary herb plant commonly used as a galactagogue. Both plants have independently recruited pairs of cytochromes P450 that catalyze oxidative 5,6-spiroketalization of cholesterol to produce diosgenin, with evolutionary progenitors traced to conserved phytohormone metabolism. This study paves the way for engineering the production of diosgenin and derived analogs in heterologous hosts.Chu, H., Liao, X., Chen, Z., Zhao, X., Liu, W., 2019. Estimating carbon geosequestration capacity in shales based on multiple fractured horizontal well: A case study. Journal of Petroleum Science and Engineering 181, 106179., shale reservoirs have been though as good candidates for CO2 geosequestration for reduction of carbon emission. When estimating the carbon geosequestration capacity, multiple fractured horizontal well (MFHW) is a prerequisite for consideration when shale reservoirs are included in candidate geological sites, as it is one of the critical factors for the successful development of shale reservoirs. In order to perfect our previous works, a new model is proposed to calculate the carbon geosequestration capacity of depleted shale reservoirs based on MFHW. The methodology calculates carbon geosequestration capacity of shale reservoirs by considering Knudsen diffusion, molecular diffusion, supercritical Langmuir adsorption, stimulated reservoir volume (SRV), and stress-sensitivity of the permeability. Utilizing the perturbation transformation technique, finite difference method, and Laplace transform technique, our method is more in accordance with the actual situations, allowing us to accurately estimate the carbon storage capacity by capturing the transient pressure response of the MFHW. A field case from the Ordos Basin in China presents that the CO2 geosequestration capacity is proportional to the dimensionless fracture half-length and conductivity. The properties of hydraulic fractures only affect the early period of the CO2 geosequestration process. For the adsorption coefficient and flow coefficient ratio, with the change of these parameters, the middle and late periods of the CO2 geosequestration process are mainly influenced.?irkovi?, M.M., 2019. The reports of expunction are grossly exaggerated: a reply to Robert Klee. International Journal of Astrobiology 18, 14-17. paper by Robert Klee in this journal argues that we should endorse a form of cosmic pessimism due to the inevitable destruction of Earth and humanity, allegedly meaning the complete and total annihilation of all traces of humanity's existence (‘human expunction’). It could be shown that both the physical basis and philosophical methodology used by Klee to reach those bleak conclusions are at best premature and at worst unwarranted and misleading. Even worse, they reflect a mindset of unjustified and narrow-minded technological and societal pessimism, which contributes to the erosion of the Enlightenment values, the loss of public interest in space research and colonization, and could indeed increase vulnerability to real – as opposed to uncertain eschatological – global risks humanity is facing in this millennium.Clark, J.B., Neale, P., Tzortziou, M., Cao, F., Hood, R.R., 2019. A mechanistic model of photochemical transformation and degradation of colored dissolved organic matter. Marine Chemistry 214, 103666. degradation (PD) of colored dissolved organic matter (CDOM) is a key transformational process for both natural and anthropogenic DOM. A fully mechanistic model is presented that can simulate laboratory incubations of the controlled PD of marsh and estuarine derived CDOM. The model was designed and optimized to recreate the loss of absorbance for marsh low tide and estuarine samples, representing high molecular weight allochthonous and mid molecular weight estuarine CDOM. In the model, high specific absorbance fractions representative of marsh and estuarine CDOM are transformed into a low specific absorbance fraction representative of coastal ocean CDOM as well as non-colored fractions. The various transformations in the model have maximum apparent quantum yields (at 284?nm) that range from 3.22?×?10?8?±?1.75 to 56.05?±?21.5 [mmol C (mol photons)?1], with non-colored DOM/inorganic carbon production outpaced by inter-molecular organic carbon transformations. Model performance was tested using an independent incubation data set whereby experimental results of photobleaching of spectral absorbance at 300?nm were recreated with a Willmott model skill of 0.98 and mean percent error of ?3.66%. The production of the low molecular weight photodegraded end member ranged from 0.52 to 4.86?μmol C L?1?h?1.Clifford, E.L., Varela, M.M., De Corte, D., Bode, A., Ortiz, V., Herndl, G.J., Sintes, E., 2019. Taurine is a major carbon and energy source for marine prokaryotes in the North Atlantic Ocean off the Iberian Peninsula. Microbial Ecology 78, 299-312., an amino acid-like compound, acts as an osmostress protectant in many marine metazoans and algae and is released via various processes into the oceanic dissolved organic matter pool. Taurine transporters are widespread among members of the marine prokaryotic community, tentatively indicating that taurine might be an important substrate for prokaryotes in the ocean. In this study, we determined prokaryotic taurine assimilation and respiration throughout the water column along two transects in the North Atlantic off the Iberian Peninsula. Taurine assimilation efficiency decreased from the epipelagic waters from 55?±?14% to 27?±?20% in the bathypelagic layers (means of both transects). Members of the ubiquitous alphaproteobacterial SAR11 clade accounted for a large fraction of cells taking up taurine, especially in surface waters. Archaea (Thaumarchaeota + Euryarchaeota) were also able to take up taurine in the upper water column, but to a lower extent than Bacteria. The contribution of taurine assimilation to the heterotrophic prokaryotic carbon biomass production ranged from 21% in the epipelagic layer to 16% in the bathypelagic layer. Hence, we conclude that dissolved free taurine is a significant carbon and energy source for prokaryotes throughout the oceanic water column being utilized with similar efficiencies as dissolved free amino acids.Cockell, C.S., Holt, J., Campbell, J., Groseman, H., Josset, J.-L., Bontognali, T.R.R., Phelps, A., Hakobyan, L., Kuretn, L., Beattie, A., Blank, J., Bonaccorsi, R., McKay, C., Shirvastava, A., Stoker, C., Willson, D., McLaughlin, S., Payler, S., Stevens, A., Wadsworth, J., Bessone, L., Maurer, M., Sauro, F., Martin-Torres, J., Zorzano, M.-P., Bhardwaj, A., Soria-Salinas, A., Mathanlal, T., Nazarious, M.I., Ramachandran, A.V., Vaishampayan, P., Guan, L., Perl, S.M., Telling, J., Boothroyd, I.M., Tyson, O., Realff, J., Rowbottom, J., Lauernt, B., Gunn, M., Shah, S., Singh, S., Paling, S., Edwards, T., Yeoman, L., Meehan, E., Toth, C., Scovell, P., Suckling, B., 2019. Subsurface scientific exploration of extraterrestrial environments (MINAR 5): analogue science, technology and education in the Boulby Mine, UK. International Journal of Astrobiology 18, 157-182. deep subsurface of other planetary bodies is of special interest for robotic and human exploration. The subsurface provides access to planetary interior processes, thus yielding insights into planetary formation and evolution. On Mars, the subsurface might harbour the most habitable conditions. In the context of human exploration, the subsurface can provide refugia for habitation from extreme surface conditions. We describe the fifth Mine Analogue Research (MINAR 5) programme at 1 km depth in the Boulby Mine, UK in collaboration with Spaceward Bound NASA and the Kalam Centre, India, to test instruments and methods for the robotic and human exploration of deep environments on the Moon and Mars. The geological context in Permian evaporites provides an analogue to evaporitic materials on other planetary bodies such as Mars. A wide range of sample acquisition instruments (NASA drills, Small Planetary Impulse Tool (SPLIT) robotic hammer, universal sampling bags), analytical instruments (Raman spectroscopy, Close-Up Imager, Minion DNA sequencing technology, methane stable isotope analysis, biomolecule and metabolic life detection instruments) and environmental monitoring equipment (passive air particle sampler, particle detectors and environmental monitoring equipment) was deployed in an integrated campaign. Investigations included studying the geochemical signatures of chloride and sulphate evaporitic minerals, testing methods for life detection and planetary protection around human-tended operations, and investigations on the radiation environment of the deep subsurface. The MINAR analogue activity occurs in an active mine, showing how the development of space exploration technology can be used to contribute to addressing immediate Earth-based challenges. During the campaign, in collaboration with European Space Agency (ESA), MINAR was used for astronaut familiarization with future exploration tools and techniques. The campaign was used to develop primary and secondary school and primary to secondary transition curriculum materials on-site during the campaign which was focused on a classroom extra vehicular activity simulation.Colaninno, C.E., Hadden, C.S., Springman, S.J., Chick, J.H., Allison, J.R., Brauer, M.S., Camp, C.A., Huaylinos, A.C., Klush, S.A., Lange, E.R., McBride, J.M., Mullenax, O.A., Ridley, H.C., Umbricht, P.M., 2019. Effects of exposure to nixtamalization liquid on bone collagen δ13C and δ15N and archaeological implications. Journal of Archaeological Science: Reports 27, 101935. use of stable isotopes in zooarchaeology is common; however, the effects of many cooking and post-depositional processes on the chemical composition of faunal remains are understood poorly. People of the Americas processed maize through nixtamalization, a method of preparing grains by soaking and cooking them in an alkaline solution. Once discarded, nixtamalization wastewater may have contacted other food waste, such as bone. We examine the effects of alkaline exposure on stable isotopes (δ13C and δ15N) in fish bone collagen. Bony structures of four modern shortnose gar (Lepisosteus platostomus), a commonly identified taxon in eastern North American zooarchaeological assemblages, were exposed to four treatments that varied in alkalinity and duration of exposure. No significant differences were observed between treated and untreated specimens in δ13C values. Prolonged exposure to a highly alkaline solution caused a shift in bone collagen δ15N values of approximately ?0.44‰. The extreme conditions required to cause this shift suggests that the byproduct of nixtamalization would have negligible effects on archaeological bone collagen δ13C and δ15N values.Cooke, I.R., Sims, I.R., 2019. Experimental studies of gas-phase reactivity in relation to complex organic molecules in star-forming regions. ACS Earth and Space Chemistry 3, 1135-1150. field of astrochemistry concerns the formation and abundance of molecules in the interstellar medium, star-forming regions, exoplanets, and solar system bodies. These astrophysical objects contain the chemical material from which new planets and solar systems are formed. Around 200 molecules have thus far been observed in the interstellar medium; almost half containing six or more atoms and considered “complex” by astronomical standards. All of these complex molecules consist of at least one carbon atom and thus the term complex organic molecules (COMs) has been coined by the astrochemical community. In order to understand the formation and destruction of these COMs under the extreme conditions of star-forming regions, three kinds of activity are involved: (1) the astronomical identification of complex molecules present in the interstellar medium; (2) the construction of astrochemical models that attempt to explain the formation routes of the observed molecules; and (3) laboratory measurements and theoretical calculations of critical kinetic parameters that are included in the models. In the following review, we present recent laboratory efforts to produce quantitative kinetic data for gas-phase reactions at low temperatures. We discuss the use of the CRESU technique, a French acronym standing for Cinétique de Réaction en Ecoulement Supersonique Uniforme, which means reaction kinetics in uniform supersonic flow, to measure reactions of astrochemical importance. In particular, we highlight recent and future advances in the measurement of product-specific reaction kinetics at low temperatures.Covas, T.R., Rocha, Y.d.S., Spigolon, A.L.D., Pereira, R.C.L., Valencia-Dávila, J.A., Rangel, M.D., Vaz, B.G., 2019. Evaluation of the effects of the simulated thermal evolution of a Type-I source rock on the distribution of basic nitrogen-containing compounds. Fuel 254, 115685. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) allows the molecular-level characterization of ultracomplex mixtures such as crude oil samples. By combining FT-ICR MS with electrospray ionization, a myriad of polar compounds can routinely be identified and assigned with unmatched mass resolution and accuracy. The profile of polar compounds containing NSO atoms can be used to track and evaluate important parameters of crude oil. Recently, using ESI FT-ICR MS in the negative mode (), we investigated changes in the profile of polar compounds as a function of thermal maturity. Sulfur-containing compounds are completely destroyed during maturation, and the relatively high content of O-containing compounds decreases via decarboxylation and dehydration. The number of double bond equivalents (DBE) increased, indicating the occurrence of aromatization and condensation. However, the carbon number distribution shifted to lower values as a function of thermal maturity. Six regressions based on changes in the contents of O2 compounds were proposed as maturity parameters. Here, by focusing on tracking and evaluating the impact of thermal maturity on basic polar compounds, a set of hydrous pyrolysis (HP) products was analyzed using an ESI(+) 7.2 T LTQ FT-ICR MS system. The samples at various stages of maturity consist of one immature bitumen (original sample), eleven expelled oil samples and eight residual bitumen samples. Determining the changes in the contents of N- and NO-containing compounds with maturity allows us to propose new parameters for assessing thermal maturity that cover the full window of oil generation.Creamer, C.A., Foster, A.L., Lawrence, C., McFarland, J., Schulz, M., Waldrop, M.P., 2019. Mineralogy dictates the initial mechanism of microbial necromass association. Geochimica et Cosmochimica Acta 260, 161-176. organic matter (SOM) improves soil fertility and mitigates disturbance related to climate and land use change. Microbial necromass (the accumulated cellular residues of microorganisms) comprises the majority of soil C, yet the formation and persistence of necromass in relation to mineralogy is poorly understood. We tested whether soil minerals had different microbial necromass association mechanisms. Specifically, we tested whether microbial necromass directly sorbed to mineral surfaces or was consumed by live microorganisms prior to mineral association. Applying Raman microspectroscopy with 13C enriched microbial necromass to quantify microbe-mineral interactions, we show that mineralogy alters the initial mechanism of microbial necromass association. In the presence of K-feldspar (lower abiotic C preservation potential), microbial necromass required assimilation by live microorganisms for mineral retention. In contrast, with amorphous aluminum hydroxide (higher abiotic C preservation potential) microbial necromass was retained predominately through abiotic sorption, and was subsequently protected from microbial decomposition. Despite different mechanisms, both minerals retained similar quantities of microbial necromass under biotic conditions. Mineralogy determined not only the quantity of mineral-associated C, but the distinct pathway of microbial necromass association. These findings show the utility of Raman microspectroscopy as a technique to study microbe-mineral interactions, and imply that heterogeneity in mineral-organic interactions could result in gradients of organic matter stability.Cruikshank, D.P., Materese, C.K., Pendleton, Y.J., Boston, P.J., Grundy, W.M., Schmitt, B., Lisse, C.M., Runyon, K.D., Keane, J.T., Beyer, R.A., Summers, M.E., Scipioni, F., Stern, S.A., Dalle Ore, C.M., Olkin, C.B., Young, L.A., Ennico, K., Weaver, H.A., Bray, V.J., 2019. Prebiotic chemistry of Pluto. Astrobiology 19, 831-848. present the case for the presence of complex organic molecules, such as amino acids and nucleobases, formed by abiotic processes on the surface and in near-subsurface regions of Pluto. Pluto's surface is tinted with a range of non-ice substances with colors ranging from light yellow to red to dark brown; the colors match those of laboratory organic residues called tholins. Tholins are broadly characterized as complex, macromolecular organic solids consisting of a network of aromatic structures connected by aliphatic bridging units (e.g., Imanaka et al.,2004; Materese et al.,2014, 2015). The synthesis of tholins in planetary atmospheres and in surface ices has been explored in numerous laboratory experiments, and both gas- and solid-phase varieties are found on Pluto. A third variety of tholins, exposed at a site of tectonic surface fracturing called Virgil Fossae, appears to have come from a reservoir in the subsurface. Eruptions of tholin-laden liquid H2O from a subsurface aqueous repository appear to have covered portions of Virgil Fossae and its surroundings with a uniquely colored deposit (D.P. Cruikshank, personal communication) that is geographically correlated with an exposure of H2O ice that includes spectroscopically detected NH3 (C.M. Dalle Ore, personal communication). The subsurface organic material could have been derived from presolar or solar nebula processes, or might have formed in situ. Photolysis and radiolysis of a mixture of ices relevant to Pluto's surface composition (N2, CH4, CO) have produced strongly colored, complex organics with a significant aromatic content having a high degree of nitrogen substitution similar to the aromatic heterocycles pyrimidine and purine (Materese et al.,2014, 2015; Cruikshank et al.,2016). Experiments with pyrimidines and purines frozen in H2O-NH3 ice resulted in the formation of numerous nucleobases, including the biologically relevant guanine, cytosine, adenine, uracil, and thymine (Materese et al.,2017). The red material associated with the H2O ice may contain nucleobases resulting from energetic processing on Pluto's surface or in the interior. Some other Kuiper Belt objects also exhibit red colors similar to those found on Pluto and may therefore carry similar inventories of complex organic materials. The widespread and ubiquitous nature of similarly complex organic materials observed in a variety of astronomical settings drives the need for additional laboratory and modeling efforts to explain the origin and evolution of organic molecules. Pluto observations reveal complex organics on a small body that remains close to its place of origin in the outermost regions of the Solar System.Cubillos, C.F., Paredes, A., Yá?ez, C., Palma, J., Severino, E., Vejar, D., Grágeda, M., Dorador, C., 2019. Insights into the microbiology of the chaotropic brines of Salar de Atacama, Chile. Frontiers in Microbiology 10, 1611. doi: 10.3389/fmicb.2019.01611. life inhabiting hypersaline environments belong to a limited group of extremophile or extremotolerant taxa. Natural or artificial hypersaline environments are not limited to high concentrations of NaCl, and under such conditions, specific adaptation mechanisms are necessary to permit microbial survival and growth. Argentina, Bolivia, and Chile include three large salars (salt flats) which globally, represent the largest lithium reserves, and are commonly referred to as the Lithium Triangle Zone. To date, a large amount of information has been generated regarding chemical, geological, meteorological and economical perspectives of these salars. However, there is a remarkable lack of information regarding the biology of these unique environments. Here, we report the presence of two bacterial strains (isolates LIBR002 and LIBR003) from one of the most hypersaline lithium-dominated man-made environments (total salinity 556 g/L; 11.7 M LiCl) reported to date. Both isolates were classified to the Bacillus genera, but displayed differences in 16S rRNA gene and fatty acid profiles. Our results also revealed that the isolates are lithium-tolerant and that they are phylogenetically differentiated from those Bacillus associated with high NaCl concentration environments, and form a new clade from the Lithium Triangle Zone. To determine osmoadaptation strategies in these microorganisms, both isolates were characterized using morphological, metabolic and physiological attributes. We suggest that our characterization of bacterial isolates from a highly lithium-enriched environment has revealed that even at such extreme salinities with high concentrations of chaotropic solutes, scope for microbial life exists. These conditions have previously been considered to limit the development of life, and our work extends the window of life beyond high concentrations of MgCl2, as previously reported, to LiCl. Our results can be used to further the understanding of salt tolerance, most especially for LiCl-dominated brines, and likely have value as models for the understanding of putative extra-terrestrial (e.g., Martian) life.Cui, H., Liang, F., Ma, C., Zhong, N., Sha, Y., Ma, W., 2019. Pore evolution characteristics of Chinese marine shale in the thermal simulation experiment and the enlightenment for gas shale evaluation in South China. Geosciences Journal 23, 595-602. there are many similarities between the shale of Cambrian Qiongzhusi Formation and Ordovician Wufeng Formation–Silurian Longmaxi Formation in South China, including total organic carbon content (TOC) and thickness, the drilling results of shale gas exploration are very different. One of the reasons is the difference of the nano-pores number developed in organic matter between them. In order to reveal the causes, the black shale of Upper Proterozoic Xiamaling Formation in North China, which is similar to the marine source rock in Sichuan basin, was selected for the thermal simulation experiment, and the pore size and volume of the samples before and after the experiment were acquired by scanning electron microscopy (SEM) and nitrogen adsorption isotherm measurement. Through the SEM photographs, we found that the sizes of the organic pores in algae, dispersed organic matter and organic matter associated with clay minerals get bigger with the increasing maturity. The total pore volume, micro-pore volume and meso-pore volume of the shale acquired by nitrogen adsorption isotherm measurement increase with the increasing maturity, too. However, under the overburden pressure, micro-pore volume decreases at high maturity stage, indicating the pores in organic matter might be compressed. It is considered that the pore volume in organic matter of the shale of Qiongzhusi Formation might be compacted under greater confining pressure, which may be the reason why the pore structures of the two sets of marine shale in South China are different.D'Angelo, J.A., 2019. Molecular structure of the cuticles of Dicroidium and Johnstonia (Corystospermaceae, Triassic, Argentina). Ecophysiological adaptations of two chemically indistinguishable, morphology-based taxa. Review of Palaeobotany and Palynology 268, 109-124. of compression-preserved Dicroidium odontopteroides and Johnstonia coriacea (Corystospermaceae, Upper Triassic, Mendoza, Argentina) are spectrochemically analyzed. The objectives included (i) studying the chemical resistance of cuticles to different oxidative conditions to gain new insights into their fine molecular structure and its likely (ii) chemotaxonomical and (iii) paleoecophysiological implications. Two experimental procedures are employed to obtain the cuticles from the compressions: (a) room-temperature (25o?C and up to 75?min) and (b) high-temperature (500o?C and up to 50?min) oxidative reactions using Schulze's reagent. Details of the molecular structure (i.e., functional groups) of cuticles are studied using Fourier transform infrared (FTIR) spectroscopy followed by data evaluation using principal component analysis and one-way ANOVA test. Morphological changes as a function of different oxidative conditions are monitored by scanning electron microscopy. Results indicate that the geomacropolymers composing the cuticles of both taxa are chemically characterized by high contents of aliphatic compounds with relatively smaller amounts of aromatic hydrocarbons. The presence of considerable contents of carbonyl groups in the cuticles indicates likely ester chemical “bridges” that cross-link aliphatic and aromatic hydrocarbons. These chemical bonds “strengthen” the molecular structure, thus increasing the overall mechanical and chemical resistance of the cuticle. Conclusions include: (i) the cuticles of both taxa are extraordinarily resistant to extremely harsh chemical conditions, which modified neither morphology nor chemical structure; (ii) independently of the oxidative procedure employed, the two taxa cannot be statistically differentiated using the cuticular FTIR information; (iii) the high chemical resistance of the studied cuticles represents likely ecophysiological adaptations of the once living plants to survive stressful environmental conditions. They could have included high temperatures, elevated CO2 concentrations, seasonal drought, and nutrient-deficient, acidic soils exposed to intensive solar irradiation, and eventual acid (H2SO4) precipitations. Chemical results are in agreement with taphonomic, sedimentological, paleopedological and (micro- and macro-) morphological data, which indicate that the studied plants were likely opportunistic and stress-tolerant colonizers that dominated flood-disturbed, waterlogged lowlands.This combination of chemical and statistical tools enhances our understanding of the fine details of corystosperm cuticles regarding their structure, taxonomy, and paleoecophysiology.Dai, M., Peng, C., Liu, H., Wang, J., Ali, I., Naz, I., 2019. Analysis and imitation of organic Sanhetu concrete discovered in an ancient Chinese tomb of Qing Dynasty. Journal of Archaeological Science: Reports 26, 101918. Organic Sanhetu Concrete (OSC) has a prominent position in the Chinese ancient construction, and especially the natural organic materials (sticky rice and egg white) have made some historical buildings legends. Compared with Portland cement, the OSC has exhibit excellent durability, impermeability and mechanical characteristics. The absorption of CO2 makes them as an environmental friendly building material during Qing Dynasty. However, it was almost lost after the emergence of Portland cement as a building material. Though, OSC have existed for thousands of years, we can't get accurate formula and process even after 200?years. Further, even the compressive strength of the imitation is not satisfactory. This paper is primarily focused on the archaeology discoveries in 2007, for that the samples were collected from the sealing earth of a Qing dynasty burial mound in Huaining, Anhui, China and analyzed to investigate its physical, chemical and mechanical characteristics. Based on the results, an imitation of OSC with organic additives was designed, combining with the formula in literature. The results of these experiments have shown that the compressive strength of the lime-based materials met that of concrete with strength grade of C20 (21?MPa) after weathering and cutting. In addition, the imitation is above 50?MPa, which was comparable to that of concrete that have strength grade of C50. Thus, it was concluded from this investigation that the substitution of the artificial organic additives to natural materials can open doors for novel research prospective in designing of building materials.Dalou, C., Füri, E., Deligny, C., Piani, L., Caumon, M.-C., Laumonier, M., Boulliung, J., Edén, M., 2019. Redox control on nitrogen isotope fractionation during planetary core formation. Proceedings of the National Academy of Sciences 116, 14485-14494.: The origin and evolution of Earth’s nitrogen is often discussed by comparing the large variation of N-isotopic compositions among Earth’s building blocks (chondrites) to the signatures of various terrestrial reservoirs. Here, we demonstrate that planetary differentiation processes, such as core formation, may have significantly modified the N-isotopic composition of the proto-Earth. During core–mantle differentiation, a significant amount of isotopically light N entered Earth’s core, producing an isotopic fractionation much larger than has been observed for other geochemical tracers of core formation. The magnitude of N-isotopic fractionation varies significantly as a function of the redox history of the early Earth. Therefore, distinct N-isotopic ratios among Earth’s reservoirs or between planetary bodies may reflect different planetary evolution processes as opposed to different N sources.Abstract: The present-day nitrogen isotopic compositions of Earth’s surficial (15N-enriched) and deep reservoirs (15N-depleted) differ significantly. This distribution can neither be explained by modern mantle degassing nor recycling via subduction zones. As the effect of planetary differentiation on the behavior of N isotopes is poorly understood, we experimentally determined N-isotopic fractionations during metal–silicate partitioning (analogous to planetary core formation) over a large range of oxygen fugacities (ΔIW ?3.1 < logfO2 < ΔIW ?0.5, where ΔIW is the logarithmic difference between experimental oxygen fugacity [fO2] conditions and that imposed by the coexistence of iron and wüstite) at 1 GPa and 1,400 °C. We developed an in situ analytical method to measure the N-elemental and -isotopic compositions of experimental run products composed of Fe–C–N metal alloys and basaltic melts. Our results show substantial N-isotopic fractionations between metal alloys and silicate glasses, i.e., from ?257 ± 22‰ to ?49 ± 1‰ over 3 log units of fO2. These large fractionations under reduced conditions can be explained by the large difference between N bonding in metal alloys (Fe–N) and in silicate glasses (as molecular N2 and NH complexes). We show that the δ15N value of the silicate mantle could have increased by ～20‰ during core formation due to N segregation into the core.Dashtbozorg, M., Riyahi Bakhtiari, A., Shushizadeh, M.R., Taghavi, L., 2019. Quantitative evaluation of n-alkanes, PAHs, and petroleum biomarker accumulation in beach-stranded tar balls and coastal surface sediments in the Bushehr Province, Persian Gulf (Iran). Marine Pollution Bulletin 146, 801-815. areas within the Bushehr Province (BP), Persian Gulf, Iran, face great challenges due to the heavy organic contamination caused by rapid industrialization, and the presence of numerous oil fields. In addition, in 2014, a significant number of tar balls are found along the coasts of BP. A total of 96 samples (48 coastal sediments and 48 tar balls) were taken from eight sampling points at the BP coast during the summer of 2014. These samples were analyzed to identify the sources and characteristics of their organic matter using diagnostic ratios and fingerprint analysis based on the distribution of the source-specific biomarkers of n-alkanes, PAHs,1 hopanes and steranes. Mean concentration of n-alkanes (μg?g?1 dw) and PAHs (ng?g?1 dw) varied respectively from 405 to 220,626, and 267 to 23,568 in coastal sediments, while ranged respectively from 664 to 145,285 and 390 to 46,426 in tar balls. In addition, mean concentration of hopanes and steranes (ng?g?1?dw) were between 18.17 and 3349 and 184.66 to 1578 in coastal sediments, whereas in tar balls were 235–1899 and 520–1504, respectively. Pri/Phy2 ratio was 0.25 to 1.51 (0.65) and 0.36 to 1 (0.63) in coastal sediment and tar ball samples, respectively, and the occurrence of UCM3 in both matrices, reflecting the petrogenic OM4 inputs and chronic oil contamination, respectively. The C30 and C29 homologues followed Gammacerane were detected in both matrices, in particular those collected from intensive industrial activities, suggesting petrogenic sources of OM. The coastal sediment PAHs profiles were significantly dominated by HMW5-PAHs in the Bahregan Beach (BAB) (78% of total PAHs), Bandare-Genaveh (GP) (66%), and Bandare-Bushehr (BUB) (61%) stations, while the Bashi Beach (BSB) (40%), Bandare-Kangan (KP) (57%), and Bandare-Asaluyeh (AP) (51%) stations exhibited higher proportion of LMW6-PAHs. PCA7 indicated that the tar ball and coastal sediment samples deposited along the Southwest of the BP beaches are most likely originated from the Abuzar oil. Based on the intensity of the anthropogenic activities, NPMDS8 analysis revealed that the GP, BAB, NNP, AP, and KP sampling sites had a high concentration of detected organic pollutants. To the best of our knowledge, this is the first study that investigates oil pollution in costal sediments and tar balls in the BP, providing insights in to the fate of oil in the coastal areas of the Persian Gulf, Iran.David, V., Galaon, T., Bacalum, E., 2019. Sample enrichment by solid-phase extraction for reaching parts per quadrillion levels in environmental analysis. Chromatographia 82, 1139-1150. of parts per quadrillion (ppq) levels of various pollutants, contaminants, or background species in environmental samples is a challenging task for analytical chemistry. Among them, dioxins, perfluoroalkylated acids, organophosphorus and organochlorine pesticides, herbicides, and nitrosamines are found in the environment and consequently they must be determined at ppq levels. Analytical techniques alone are not able to reach these concentration levels, and they can be utilized only if sample enrichment is applied. This review is based on the literature reporting analytical methods based on solid-phase extraction or related techniques that are applied to determine ppq levels or have quantitation limits below the parts per trillion (ppt) range. Some other important aspects of the analytical process, such as calibration, precision, recovery, uncertainty, environmental matrix certified reference materials, or interlaboratory comparison, are discussed in the context of this analytical research.de Leeuw, K.D., Buisman, C.J.N., Strik, D.P.B.T.B., 2019. Branched medium chain fatty acids: Iso-caproate formation from iso-butyrate broadens the product spectrum for microbial chain elongation. Environmental Science & Technology 53, 7704-7713. elongation fermentation can be used to convert organic residues into biobased chemicals. This research aimed to develop a bioprocess for branched medium chain fatty acids (MCFAs) production. A long-term continuous reactor experiment showed that iso-caproate (4-methyl pentanoate, i-C6) can be produced via ethanol based chain elongation. The enriched microbiome formed iso-caproate from iso-butyrate at a rate of 44 ± 6 mmol C L–1 day–1 during the last phase. This amounted to 20% of all formed compounds based on carbon atoms. The main fermentation product was n-caproate (55% of all carbon), as a result of acetate and subsequent n-butyrate elongation. The microbiome preferred straight-chain elongation over branched-chain elongation. Lowering the acetate concentration in the influent led to an increase of excessive ethanol oxidation (EEO) into electron equivalents (e.g., H2) and acetate. The formed acetate in turn stimulated straight chain elongation, but the resulting lower net acetate supply rate towards straight chain elongation led to an increased selectivity towards and productivity of i-C6. The electrons produced via oxidation routes and chain elongation were apparently utilized by hydrogenotrophic methanogens, homoacetogens, and carboxylate-to-alcohol reducing bacteria. Further improvements could be achieved if the acetate-producing EEO was minimized and limitations of ethanol and CO2 were prevented.De Middeleer, G., Leys, N., Sas, B., De Saeger, S., 2019. Fungi and mycotoxins in space—a review. Astrobiology 19, 915-926. are not only present on Earth but colonize spacecraft and space stations as well. This review provides an extensive overview of the large and diverse group of fungal species that have been found in space, as well as those corresponding detection methods used and the existing and potential future prevention and control strategies. Many of the identified fungal species in space, such as Aspergillus flavus and Alternaria sp., are mycotoxigenic; thus, they are potential mycotoxin producers. This indicates that, although the fungal load in space stations tends to be non-alarming, the effects should not be underestimated, since the effect of the space environment on mycotoxin production should be sufficiently studied as well. However, research focused on mycotoxin production under conditions found on space stations is essentially nonexistent, since these kinds of spaceflight experiments are rare. Consequently, it is recommended that detection and monitoring systems for fungi and mycotoxins in space are at some point prioritized such that investigations into the impact of the space environment on mycotoxin production is addressed. de Sousa, A.G.G., Tomasino, M.P., Duarte, P., Fernández-Méndez, M., Assmy, P., Ribeiro, H., Surkont, J., Leite, R.B., Pereira-Leal, J.B., Torgo, L., Magalh?es, C., 2019. Diversity and composition of pelagic prokaryotic and protist communities in a thin Arctic sea-ice regime. Microbial Ecology 78, 388-408. of the most prominent manifestations of climate change is the changing Arctic sea-ice regime with a reduction in the summer sea-ice extent and a shift from thicker, perennial multiyear ice towards thinner, first-year ice. These changes in the physical environment are likely to impact microbial communities, a key component of Arctic marine food webs and biogeochemical cycles. During the Norwegian young sea ICE expedition (N-ICE2015) north of Svalbard, seawater samples were collected at the surface (5?m), subsurface (20 or 50?m), and mesopelagic (250?m) depths on 9 March, 27 April, and 16 June 2015. In addition, several physical and biogeochemical data were recorded to contextualize the collected microbial communities. Through the massively parallel sequencing of the small subunit ribosomal RNA amplicon and metagenomic data, this work allows studying the Arctic’s microbial community structure during the late winter to early summer transition. Results showed that, at compositional level, Alpha- (30.7%) and Gammaproteobacteria (28.6%) are the most frequent taxa across the prokaryotic N-ICE2015 collection, and also the most phylogenetically diverse. Winter to early summer trends were quite evident since there was a high relative abundance of thaumarchaeotes in the under-ice water column in late winter while this group was nearly absent during early summer. Moreover, the emergence of Flavobacteria and the SAR92 clade in early summer might be associated with the degradation of a spring bloom of Phaeocystis. High relative abundance of hydrocarbonoclastic bacteria, particularly Alcanivorax (54.3%) and Marinobacter (6.3%), was also found. Richness showed different patterns along the depth gradient for prokaryotic (highest at mesopelagic depth) and protistan communities (higher at subsurface depths). The microbial N-ICE2015 collection analyzed in the present study provides comprehensive new knowledge about the pelagic microbiota below drifting Arctic sea-ice. The higher microbial diversity found in late winter/early spring communities reinforces the need to continue with further studies to properly characterize the winter microbial communities under the pack-ice.Deese, R.D., Morris, R.E., Metz, A.E., Myers, K.M., Johnson, K., Loegel, T.N., 2019. Characterization of organic nitrogen compounds and their impact on the stability of marginally stable diesel fuels. Energy & Fuels 33, 6659-6669. set of low-sulfur diesel fuels from the Western Pacific region were found to be unstable during storage although they passed all standard specification tests. This sample set was found to have high nitrogen content. Initially, liquid–liquid extractions with a mild aqueous acid were performed to separate basic and nonbasic nitrogen groups in an attempt to determine if these organonitrogen classes were responsible for the poor stability. The findings of this study indicate that there may be a correlation between the acid-extractable nitrogen compounds in these fuels and the formation of high levels of particulates in storage. To develop a more comprehensive understanding of the classes and distributions of organonitrogen compounds in fuels, a novel analytical method was developed using two-dimensional gas chromatography with nitrogen chemiluminescence detection (GCxGC-NCD). The GCxGC-NCD analyses revealed the presence of three distinct groups of nitrogen compounds. One group corresponded to the acid-extractable basic nitrogen compounds, one with the nonbasic nitrogen compounds, and a third early-eluting lighter polar organonitrogen fraction that had previously not been observed. This light organonitrogen fraction was unique to these particularly unstable fuels. If this is found to be universally applicable, this light polar nitrogen fraction may serve as an indicator of potentially unstable diesel fuels. Overall, the GCxGC-NCD method has been shown to be a valuable tool to enhance our understanding of the chemistry of organonitrogen species and their impact on fuel stability.Delgado-Baquerizo, M., 2019. Obscure soil microbes and where to find them. The ISME Journal 13, 2120-2124. soil bacteria and fungi remain unclassified at the highest taxonomic ranks (e.g. phyla level), which hampers our ability to assess the ecology and functional capabilities of these soil organisms in terrestrial ecosystems globally. The first logical step toward the classification of these unknown soil taxa is to identify potential locations on Earth where these unclassified bacteria and fungi are feasibly most prevalent. To do this, here I used data from a global soil survey across 235 locations, including amplicon sequencing information for fungal and bacterial communities, and generated global atlases highlighting those soils where the percentages of taxa of bacteria and fungi with an unknown phyla are expected to be more prevalent. Results indicate that soil samples with the largest percentage of fungal taxa with an unknown phyla can be found in dry forests and grasslands, while those with the largest percentage of bacterial taxa with an unknown phyla are found in boreal and tropical forests. This information can be used by taxonomists and microbiologists to target these potentially new soil taxa.Deliang, F., Shixin, Z., Guosheng, X., Tao, T., Yu, M., 2019. Phase characteristics and geological significance of coal-generated hydrocarbon: Take the Minhe Basin as an example. Energy Exploration & Exploitation 37, 1306-1319. phase characteristics of petroleum fluids are directly related to the hydrocarbon accumulation, and through exploration and development, the evolution process of hydrocarbon generation from coal is found to be complex, with variable fluid phases. To explore the relationship between the hydrocarbon generation process and fluid phase evolution of the coal, we derive the kinetic parameters for the gaseous hydrocarbons and methane generated from a series of closed-system laboratory pyrolysis tests of a Jurassic coal from the Minhe Basin and established a phase evolution diagram of the coal-generated fluids and the corresponding geological conditions. The study shows that with a fixed frequency factor of 1.0?×?1014/s, the mean values of activation energies of C1 and C1–5 are 64.55 kCal/mol and 63.93 kCal/mol, respectively. The phase of the coal-generated hydrocarbon fluids produced under geological conditions shows that an undersaturated oil phase or an oil–gas phases is possible when Easy%Ro <1.08, any phase is possible when Easy%Ro is between 1.08 and 1.36, an undersaturated gas phase or an oil–gas phases is possible when Easy%Ro is between 1.36 and 2.05, and a gas phase is possible when Easy%Ro?>?2.05. The hydrocarbon generated from the Jurassic coal of the Minhe Basin started as an oil phase in the Early Cretaceous, and the fluid phase may have changed from oil phase to oil–gas phases in the late Early Cretaceous, The fluid changed to gas phase after the Miocene. Additionally, the source rock is still in the stage of gas generation currently.Demény, A., Gugora, A.D., Kesjár, D., Lécuyer, C., Fourel, F., 2019. Stable isotope analyses of the carbonate component of bones and teeth: The need for method standardization. Journal of Archaeological Science 109, 104979. addition to the collagen and phosphate components of bones and teeth, the stable carbon and oxygen isotope compositions of skeletal carbonate are frequently measured to determine diet, environmental conditions, and populational or individual migration in bioarchaeological research. A standardized method for the stable isotopic analysis of skeletal carbonate has not yet been established, despite the importance of these data. In this study, significant differences in the stable oxygen isotope values of bones and dental enamel were observed, which arose due to instrument- and methodology-based differences. The same target archaeological samples were analyzed in three laboratories, and the stable isotope analyses were supplemented by Fourier Transformation Infrared Spectroscopy (FTIR) measurements, which detected a strong OH? concentration-dependence in the stable oxygen isotopic shifts measured between the three laboratories. Laboratory experiments were conducted to quantify the effects of reaction temperature and phosphoric acid (H3PO4) concentration on the oxygen isotopic composition of carbonate, both of which resulted in significant, though smaller δ18O changes than the OH-related δ18O change. As such, we suggest that the δ18O values of bone structural carbonate should not be included in anthropological interpretation and that the analysis of tooth enamel should be conducted at 70?°C using 102% H3PO4, in order to make the results comparable. Furthermore, carbonated hydroxylapatite (CHAP) reference materials with varied isotopic compositions should be developed in the near future.Deng, N., Stack, A.G., Weber, J., Cao, B., De Yoreo, J.J., Hu, Y., 2019. Organic–mineral interfacial chemistry drives heterogeneous nucleation of Sr-rich (Bax, Sr1?x)SO4 from undersaturated solution. Proceedings of the National Academy of Sciences 116, 13221-13226.: The wide occurrence of Sr-rich marine barite in undersaturated seawater presents a paradox. Here, in undersaturated solution, we observe barite nucleation on organic films and show it is enabled by cation enrichment. In supersaturated solution, this enrichment generates nanometer-sized Sr-rich nuclei on organic films, while Sr-poor barite grows quickly to micrometer-sized crystals in bulk solutions. Theoretical solid-solution calculations explain the distinct Sr incorporation in barites on organic films and in bulk solutions. The findings resolve the barite paradox and provide insights into manipulating solid-solution nucleation and growth through the unique chemical environment near organic–mineral interfaces, which may revise our understanding of many biomineralization processes and allow strategies for tailoring material synthesis to achieve desired sizes and compositions.Abstract: Sr-bearing marine barite [(Bax, Sr1?x)SO4] cycling has been widely used to reconstruct geochemical evolutions of paleoenvironments. However, an understanding of barite precipitation in the ocean, which is globally undersaturated with respect to barite, is missing. Moreover, the reason for the occurrence of higher Sr content in marine barites than expected for classical crystal growth processes remains unknown. Field data analyses suggested that organic molecules may regulate the formation and composition of marine barites; however, the specific organic–mineral interactions are unclear. Using in situ grazing incidence small-angle X-ray scattering (GISAXS), size and total volume evolutions of barite precipitates on organic films were characterized. The results show that barite forms on organic films from undersaturated solutions. Moreover, from a single supersaturated solution with respect to barite, Sr-rich barite nanoparticles formed on organics, while micrometer-size Sr-poor barites formed in bulk solutions. Ion adsorption experiments showed that organic films can enrich cation concentrations in the adjacent solution, thus increasing the local supersaturation and promoting barite nucleation on organic films, even when the bulk solution was undersaturated. The Sr enrichment in barites formed on organic films was found to be controlled by solid-solution nucleation rates; instead, the Sr-poor barite formation in bulk solution was found to be controlled by solid-solution growth rates. This study provides a mechanistic explanation for Sr-rich marine barite formation and offers insights for understanding and controlling the compositions of solid solutions by separately tuning their nucleation and growth rates via the unique chemistry of solution–organic interfacesDeng, T., Li, Y., Wang, Z., Yu, Q., Dong, S., Yan, L., Hu, W., Chen, B., 2019. Geochemical characteristics and organic matter enrichment mechanism of black shale in the Upper Triassic Xujiahe Formation in the Sichuan basin: Implications for paleoweathering, provenance and tectonic setting. Marine and Petroleum Geology 109, 698-716. first, third and fifth members (henceforth referred to as T3x1, T3x3 and T3x5, respectively) of the Upper Triassic coal-bearing Xujiahe Formation black shale are among the most significant hydrocarbon source rocks in the Sichuan basin. Here, we present geochemical data for the Upper Triassic black shales from core from Well LD-1 to determine their paleoenvironmental conditions, paleoweathering, provenance transitions and tectonic setting. The V/(V + Ni) vs. U/Th, V/Cr vs. U/Th and Ni/Co vs. U/Th bivariate plots and the TFe-TOC-TS (total Fe-total organic carbon-total Sulphur) ternary diagram indicate that the synsedimentary redox regime of almost all the shale samples was oxidizing. Ba/Al, Sr/Al and P/Ti data combined with quantitative biogenic Ba data indicate that moderate-high primary paleoproductivity levels prevailed during deposition. The Sr/Cu ratio and C-value combined with the sedimentary features are indicative of warm-humid climate conditions. The Ti/Al deposition rate proxy and decompacted sedimentation rate are positively correlated with the total organic carbon (TOC) content. According to our multiproxy approach, black shale development in the Xujiahe Formation was mainly controlled by the primary productivity level, foreland basin setting, high tectonic subsidence and sedimentation rate and exhibited a limited correlation with water column redox conditions. Through the compilation and calculation of various weathering indices for the Xujiahe black shale, we suggest that caution must be taken when inferring paleoclimate characteristics based on the chemical index of alteration (CIA) because of the influence of multiple nonweathering factors. Provenance-sensitive elemental ratios (Th/Sc vs. Zr/Sc and Co/Th vs. La/Sc) indicate that the clastic contribution to Xujiahe black shales was of a predominantly felsic character. The black shales exhibit a transition from T3x1 to T3x3 to T3x5, whereby T3x1 was primarily sourced from the Proterozoic to early Paleozoic strata of the Qinling orogeny, T3x3 was primarily sourced from the Neoproterozoic complex in the Longmen Shan, and T3x5 was primarily sourced from the Songpan-Ganzi flysch strata, which contributed recycled material because of folding and strong southeastward thrusting.Dhawan, H., Sharma, D.K., 2019. Advances in the chemical leaching (inorgano-leaching), bio-leaching and desulphurisation of coals. International Journal of Coal Science & Technology 6, 169-183. still remains an important source of power generation world over. Along with its usage, comes unwanted generation of noxious gas emissions, toxic metal releases into wastewater and other pollutants which ultimately lead to environmental concerns. So cleaning of coal through physical or chemical processes becomes utmost important. There are several coals which cannot be cleaned by physical beneficiation techniques to produce low ash cleaner coals. Such coals can be cleaned only through chemical cleaning techniques. The present paper reviews the chemical demineralisation and desulphurisation of coals over the years using various inorganic and organic acids, alkalis, oxidants, leachants and various acids and alkali-acid combinations to reduce the ash and sulphur contents in coals. As high as 90% demineralisation and desulfurization could be achieved with the use of these cheap inorganic acids as compared to the expensive solvents used for solvent extraction processes, a parallel approach of cleaning and refining coals.Di, P., Feng, D., Chen, D., 2019. The distribution of dissolved methane and its air-sea flux in the plume of a seep field, Lingtou Promontory, South China Sea. Geofluids 2019, 3240697. (CH4), the most abundant hydrocarbon gas in the atmosphere, plays an important role in global climate change. Quantifying the dissolved methane and its air-sea flux from hydrocarbon seeps is therefore of great importance. Large quantities of natural gas are emitted from the seafloor to the coastal ocean near the Lingtou Promontory, South China Sea. We quantified concentrations of methane in surface and bottom waters at 48 stations in a 56?km2 study area. High spatial variability in dissolved methane concentrations was observed in the surface mixed layer (0.5?m water depth) and bottom water (water-sediment interface), with values ranging from 2.90?nmol?L?1 to 13570.02 nmol L?1 and from 4.98 nmol L?1 to 31740.02 nmol L?1, respectively. The significant difference between concentrations of dissolved methane in surface and bottom waters suggests that most of the methane emitted from the seafloor is dissolved in the water column. The dissolution of methane in seawater may result in local oxygen depletion that may lead to ecological effects. The δ13C values of dissolved methane ranging from ?59.76‰ to ?48.59‰ indicate a mixture of biogenic and thermogenic gas sources. The average air-sea methane flux of Yinggehai Basin was 672.57 μmol m?2 d?1, which cannot be ignored in environment assessment. Coastal regions, especially with hydrocarbon seeps in shallow waters of the continental margin, may therefore be an important source of methane to the atmosphere.Diaz, O.C., Yarranton, H.W., 2019. Applicability of simulated distillation for heavy oils. Energy & Fuels 33, 6083-6087. applicability of simulated distillation (SimDist) for the characterization of heavy oils and bitumen is examined with a focus on the fraction of the oil corresponding to the distillation residue. To assess SimDist, atmospheric equivalent boiling points from a SimDist assay, a conventional physical distillation assay, and a deep vacuum distillation assay were compared for three heavy oil samples from different geographical regions. All of the data were obtained from the literature. The SimDist data matched the distillation data to within its reported repeatability of ±7 °C in the range of 100–400 °C but deviated progressively from the distillation data beyond 400 °C, erroneously characterizing the oil as more paraffinic. The deviation in the SimDist boiling points is attributed to calibration curves based on alkane properties and possibly to the polarization of the liquid phase of the chromatograph by the aromatic and asphaltenic components of the bitumen. A Gaussian extrapolation of the SimDist data fitted to the boiling points below 400 °C matched the boiling points from the physical distillation to within ±10 °C.do Nascimento-Dias, B.L., 2019. Combination between Ca, P and Y in the martian meteorite NWA 6963 could be used as a strategy to indicate liquid water reservoirs on ancient Mars? International Journal of Astrobiology 18, 151-156. we have learned much about the geological characteristics and history of Mars, the gaps in our knowledge certainly exceed what we understand. Martian meteorites, such as Northwest Africa (NWA) 6963, can be excellent materials for understanding the present and past of Mars, as part of the records of the planet's evolution is preserved in these extraterrestrial rocks. Micro X-ray fluorescence provided data, in which it was possible to verify the presence of Ca, P and Y elements, which are call attention because they were detected superimposed in certain regions. The way these elements were detected indicates the formation of minerals composed by the combination of these elements, such as, for example, Calcite (CaCO3), Apatite [Ca5(PO4)3(OH, F, Cl)], Merrilite [Ca9NaMg (PO4)7] and Xenotime (YPO4). These minerals are great indicators of aqueous environments. In general, the formation of these minerals is due to processes involving hydrothermal fluids or sources (>100 °C). Some geological indications suggest that in the past there might have been a large amount of liquid water, which could have accumulated large reservoirs below the Martian surface. Thus, the laboratory study of Martian meteorites and interpretations of minerals present in these samples can contribute in a complementary way to the existing results of telescopic observations and/or missions of space probes as a strategy to indicate reservoirs of liquid water.Drabek-Maunder, E., Greaves, J., Fraser, H.J., Clements, D.L., Alconcel, L.N., 2019. Ground-based detection of a cloud of methanol from Enceladus: when is a biomarker not a biomarker? International Journal of Astrobiology 18, 25-32.'s moon Enceladus has vents emerging from a sub-surface ocean, offering unique probes into the liquid environment. These vents drain into the larger neutral torus in orbit around Saturn. We present a methanol (CH3OH) detection observed with IRAM 30-m from 2008 along the line-of-sight through Saturn's E-ring. Additionally, we also present supporting observations from the Herschel public archive of water (ortho-H2O; 1669.9 GHz) from 2012 at a similar elongation and line-of-sight. The CH3OH 5(1,1)-4(1,1) transition was detected at 5.9σ confidence. The line has 0.43 km s?1 width and is offset by +8.1 km s?1 in the moon's reference frame. Radiative transfer models allow for gas cloud dimensions from 1750 km up to the telescope beam diameter ~73 000 km. Taking into account the CH3OH lifetime against solar photodissociation and the redshifted line velocity, there are two possible explanations for the CH3OH emission: methanol is primarily a secondary product of chemical interactions within the neutral torus that: (1) spreads outward throughout the E-ring or (2) originates from a compact, confined gas cloud lagging Enceladus by several km s?1. We find either scenario to be consistent with significant redshifted H2O emission (4σ) measured from the Herschel public archive. The measured CH3OH:H2O abundance (&gt;0.5%) significantly exceeds the observed abundance in the direct vicinity of the vents (~0.01%), suggesting CH3OH is likely chemically processed within the gas cloud with methane (CH4) as its parent species.Dr?ger, N., Plessen, B., Kienel, U., S?owiński, M., Ramisch, A., Tjallingii, R., Pinkerneil, S., Brauer, A., 2019. Hypolimnetic oxygen conditions influence varve preservation and δ13C of sediment organic matter in Lake Tiefer See, NE Germany. Journal of Paleolimnology 62, 181-194. carbon isotopes of sediment organic matter (δ13COM) are widely applied in paleoenvironmental studies. Interpretations of δ13COM, however, remain challenging and factors that influence δ13COM may not apply across all lakes. Common explanations for stratigraphic shifts in δ13COM include changes in lake productivity or changes in inputs of allochthonous OM. We investigated the influence of different oxygen conditions (oxic versus anoxic) on the δ13COM values in the sediments of Lake Tiefer See. We analysed (1) a long sediment core from the deepest part of the lake, (2) two short, sediment–water interface cores from shallower water depths, and (3) OM in the water column, i.e. from sediment traps. Fresh OM throughout the entire water column showed a relatively constant δ13COM value of approximately ??30.5‰. Similar values, about ??31‰, were obtained for well-varved sediments in both the long and short, sediment–water interface cores. In contrast, δ13COM values from non-varved sediments in all cores were significantly less negative (??29‰). The δ13COM values in the sediment–water interface cores from different water depths differ for sediments of the same age, if oxygen conditions at the time of deposition were different at these sites, as suggested by the state of varve preservation. Sediments deposited from AD 1924 to 1980 at 62 m water depth are varved and exhibit δ13COM values around ??31‰, whereas sediments of the same age in the core from 35 m water depth are not varved and show less negative δ13COM values of about ??29‰. The relation between varve occurrence and δ13COM values suggests that δ13COM is associated with oxygen conditions because varve preservation depends on hypolimnetic anoxia. A mechanism that likely influences δ13COM is selective degradation of OM under oxic conditions, such that organic components with more negative δ13COM are preferably decomposed, leading to less negative δ13COM values in the remaining, undegraded OM pool. Greater decomposition of OM in non-varved sediments is supported by lower TOC concentrations in these deposits (~?5%) compared to well-varved sediments (~?15%). Even in lakes that display small variations in productivity and terrestrial OM input through time, large spatial and temporal differences in hypolimnetic oxygen concentrations may be an important factor controlling sediment δ13COM.Duan, Y., Duan, M., Wu, Y., Yao, J., Li, Z., Xing, L., Liu, Y., 2019. Hydrogen and carbon isotope composition of hydrocarbon gases generated during pyrolysis of peats from different environments. Energy & Fuels 33, 5944-5953. the purpose of understanding whether the formation environment of peat precursor has a meaningful effect on the isotope ratios of thermogenic coalbed gas, pyrolysis experiments were carried out on herbaceous and reed marsh peats derived from high-latitude areas with cold dry climate and a herbaceous peat of low-latitude area with tropical moist climate. Our results show that the hydrocarbon gases generated from the herbaceous swamp peat of the high-latitude area had lighter hydrogen (?56 to ?46‰) and heavier carbon (3.3–8.2‰) isotopic compositions than those generated from the low-latitude area peat. As the peat samples were pyrolytically matured to vitrinite reflectance levels of 2.5, 3.5, and 5.5%, respectively, the hydrogen and carbon isotope ratios of the generated hydrocarbon gases increased, and the average hydrogen isotopic differences between them decreased from ?32 to ?10‰, whereas the carbon isotopic differences increased from 0.9 to 3.6‰, respectively. We suggest that the cause of these differences may originate mainly from the environmental influence on hydrogen and carbon isotopic compositions of the peats. Our results also showed that the influence of the formation environment of the peat precursor on the isotopic compositions of the pyrolysis hydrocarbon gases is less than that of types of peat. A good positive correlation of the δD or δ13C value with maturity as well as the δD value with the δ13C value of the generated hydrocarbon gases exists between the two kinds of samples, respectively, and their mathematical expressions were also established. These results showed that the environmental influence on isotopic compositions of peat should be considered when evaluating the genesis of thermogenic coalbed gas using hydrogen and carbon isotopes.Dupuis, M., Imbert, P., Odonne, F., Vendeville, B., 2019. Mud volcanism by repeated roof collapse: 3D architecture and evolution of a mud volcano cluster offshore Nigeria. Marine and Petroleum Geology 110, 368-387. 3D seismic data, we document the subsurface architecture of a cluster of 3 mud volcanoes located on the upper continental slope offshore Nigeria. In a background of gently dipping stratified sediments, the subsurface of the cluster contains 8 seismic sequences made of one subcircular syncline, 1–3?km in diameter, and adjoining unstratified units. Synclines flatten out upward through intercalation of unstratified concave-up lenses between stratified units and are eventually filled by a convex-up unstratified lens onlapped by background sediments. The lower boundary of each sequence is a 0.5–1.5?km-deep bowl-shaped unconformity across which high-dip strata rest above truncated low-dip series. We interpret each seismic sequence as a mud volcano system (MVS) sourced from a connected region and evolving through episodes of roof collapse. Three are associated with the surface mud volcanoes and another 4 to fossil ones. Mud volcano systems are dynamic features that record the evolution of: 1) the material extruded from one single connected source region (depletion zone) as it grows downwards and stepwise becomes depleted; 2) the basal unconformity, which joins strata originally separated by material evacuated in the remobilization process; by analogy with salt tectonics, we propose to call it a “mud weld”; 3) the conduits; and 4) the successive collapsed roofs of the depletion zone. The evolution of each mud volcano system in this interpretation records progressive growth of the depletion zone by downbuilding, punctuated by episodes of roof collapse and extrusion. The geometry and evolution of this type of MVS can be interpreted in the light of analogue models of magmatic caldera development: in early stages, the thin roof experiences downsagging while remobilized material is extruded through an axial pipe-like conduit; in later stages the thickened roof undergoes piston-like subsidence, and mud extrusion occurs along the peripheral fault.Duran, J.A., Schoeggl, F.F., Yarranton, H.W., 2019. Kinetics of asphaltene precipitation/aggregation from diluted crude oil. Fuel 255, 115859. precipitation kinetics were investigated for four crude oils with different asphaltene contents, each diluted with n-heptane at room conditions. The yields of precipitated asphaltenes (mass of precipitated asphaltenes divided by mass of bitumen in feed) were measured gravimetrically and the diameters of the aggregated asphaltene particles were measured using both microscopy and the focused beam reflectance method. The measurements were performed at anaerobic conditions. The data were first modeled with the geometric population balance proposed by Maqbool et al. (2011) [1]. This approach matched the yield data but not the aggregate diameters, nor did it account for the rapid (almost instantaneous) precipitation and aggregation observed in heavy oils. The model was adapted to include a simultaneous nucleation/growth/aggregation mechanism as follows: 1) the primary particles size was increased to the micrometer scale; 2) the fraction of “instantaneously” unstable asphaltenes was explicitly accounted for; 3) a nucleation term was introduced for more slowly precipitating material; 4) the collision frequency was modified to include interparticle attraction, and; 5) the experimentally observed loss of interparticle adhesion over time was explicitly accounted for in the collision efficiency. Correlations were proposed for most of the model parameters. The minimum required inputs for the model are the temperature, precipitant content, and the equilibrium asphaltene yield. The proposed model matched both yield and aggregate size kinetic data from this study and the literature.Dutta, A., Sar, P., Sarkar, J., Dutta Gupta, S., Gupta, A., Bose, H., Mukherjee, A., Roy, S., 2019. Archaeal communities in deep terrestrial subsurface underneath the Deccan Traps, India. Frontiers in Microbiology 10, 1362. doi: 10.3389/fmicb.2019.01362. community structure and potential functions within the deep, aphotic, oligotrophic, hot, igneous provinces of ～65 Myr old basalt and its Archean granitic basement was explored through archaeal 16S rRNA gene amplicon sequencing from extracted environmental DNA of rocks. Rock core samples from three distinct horizons, basaltic (BS), transition (weathered granites) (TZ) and granitic (GR) showed limited organic carbon (4–48 mg/kg) and varied concentrations (<1.0–5000 mg/kg) of sulfate, nitrate, nitrite, iron and metal oxides. Quantitative PCR estimated the presence of nearly 103–104 archaeal cells per gram of rock. Archaeal communities within BS and GR horizons were distinct. The absence of any common OTU across the samples indicated restricted dispersal of archaeal cells. Younger, relatively organic carbon- and Fe2O3-rich BS rocks harbor Euryarchaeota, along with varied proportions of Thaumarchaeota and Crenarchaeota. Extreme acid loving, thermotolerant sulfur respiring Thermoplasmataceae, heterotrophic, ferrous-/H-sulfide oxidizing Ferroplasmaceae and Halobacteriaceae were more abundant and closely interrelated within BS rocks. Samples from the GR horizon represent a unique composition with higher proportions of Thaumarchaeota and uneven distribution of Euryarchaeota and Bathyarchaeota affiliated to Methanomicrobia, SAGMCG-1, FHMa11 terrestrial group, AK59 and unclassified taxa. Acetoclastic methanogenic Methanomicrobia, autotrophic SAGMCG-1 and MCG of Thaumarcheaota could be identified as the signature groups within the organic carbon lean GR horizon. Sulfur-oxidizing Sulfolobaceae was relatively more abundant in sulfate-rich amygdaloidal basalt and migmatitic gneiss samples. Methane-oxidizing ANME-3 populations were found to be ubiquitous, but their abundance varied greatly between the analyzed samples. Changes in diversity pattern among the BS and GR horizons highlighted the significance of local rock geochemistry, particularly the availability of organic carbon, Fe2O3 and other nutrients as well as physical constraints (temperature and pressure) in a niche-specific colonization of extremophilic archaeal communities. The study provided the first deep sequencing-based illustration of an intricate association between diverse extremophilic groups (acidophile-halophile-methanogenic), capable of sulfur/iron/methane metabolism and thus shed new light on their potential role in biogeochemical cycles and energy flow in deep biosphere hosted by hot, oligotrophic igneous crust.Dutta, M., Cai, J., Gui, W., Patterson, A.D., 2019. A review of analytical platforms for accurate bile acid measurement. Analytical and Bioanalytical Chemistry 411, 4541-4549. acids are acidic steroids which help in lipid absorption, act as signaling molecules, and are key intermediate molecules between host and gut microbial metabolism. Perturbations in the circulating bile acid pool can lead to dysregulated metabolic and immunological function which?may be associated with?liver and intestinal disease. Bile acids have chemically diverse structures and are present in a?broad range of concentrations in a wide variety of samples with complex biological matrices. Advanced analytical methods are therefore required to identify and accurately quantify individual bile acids. Though enzymatic determination of total bile acid is most popular in clinical laboratories, these methods provide limited information about individual bile acids. Advanced analytical methods such as gas chromatography- and liquid chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy are?highly informative techniques which help in identification and quantification of individual bile acids in complex biological matrices. Here, we review the detection technologies currently used for bile acid identification and quantification. We further discuss the advantages and disadvantages of these analytical techniques with respect to sensitivity, specificity, robustness, and ease of use.Eichenseer, K., Balthasar, U., Smart, C.W., Stander, J., Haaga, K.A., Kiessling, W., 2019. Jurassic shift from abiotic to biotic control on marine ecological success. Nature Geoscience 12, 638-642. change and biotic interactions both govern the evolution of the biosphere, but the relative importance of these drivers over geological time remains largely unknown. Previous work suggests that, unlike environmental parameters, diversity dynamics differ profoundly between the Palaeozoic and post-Palaeozoic eras. Here we use the fossil record to test the hypothesis that the influence of ocean chemistry and climate on the ecological success of marine calcifiers decreased throughout the Phanerozoic eon. Marine calcifiers build skeletons of calcite or aragonite, and the precipitation of these calcium carbonate polymorphs is governed by the magnesium-to-calcium ratio and temperature in abiotic systems. We developed an environmental forcing model based on secular changes of ocean chemistry and temperature and assessed how well the model predicts the proliferation of skeletal taxa with respect to calcium carbonate polymorphs. Abiotic forcing governs the ecological success of aragonitic calcifiers from the Ordovician to the Middle Jurassic, but not thereafter. This regime shift coincides with the proliferation of calcareous plankton in the mid-Mesozoic. The deposition of biomineralizing plankton on the ocean floor buffers CO2 excursions and stabilizes Earth’s biochemical cycle, and thus mitigates the evolutionary impact of environmental change on the marine biota.El Atfy, H., Ghassal, B.I., Maher, A., Hosny, A., Mostafa, A., Littke, R., 2019. Palynological and organic geochemical studies of the Upper Jurassic-Lower Cretaceous successions, Western Desert, Egypt: Implications for paleoenvironment and hydrocarbon source rock potential. International Journal of Coal Geology 211, 103207. Upper Jurassic-Lower Cretaceous successions in the north Western Desert of Egypt are one of the most prolific hydrocarbon plays in North Africa. However, the source rock characteristics and depositional environments are still poorly understood. The current work assesses these sedimentary sections utilizing an integrated palynofacies and organic geochemical approach for a comprehensive source rock characterization. The investigation was carried out on 70 samples from the OBA. 3-1/1A (interval: 2540 to 3650?m) and OBA. S-C (interval: 2705 to 3782?m) wells. The results obtained are sufficient to categorically establish two types of organofacies linked to depositional environments and kerogen types, namely palynofacies PF I and PF II. The first facies (PF I) is characterized by kerogen type II and III and occurs in the Alamein and Alam El Bueib members of the Lower Cretaceous Burg El Arab Formation. This is further confirmed by pyrolysis results that revealed fair organic richness and gas generation potential in the Alamein Member with TOC ranges from 1.0 to 2.5?wt% and HI from 64 to 112?mg?HC/gTOC). The Alam El Bueib Member illustrated better organic richness and quality with TOC ranges from 1.6 to 3.1?wt% and HI from 121 to 318?mg?HC/gTOC. The thermal maturity assessment indicates that the Alamein Member is immature and the Alam El Bueib Member is early to oil-mature. PF II occurs in the Jurassic Masajid Formation, which is a transitional mature to overmature, fair to good source rock with mixed kerogen type II and III (TOC 1.3 to 2.4?wt% and HI 148 to 238?mg?HC/gTOC). The paleoenvironmental conditions were deduced mainly from the APP ternary plot. The Alamein and Alam El Bueib members were deposited in a suboxic to anoxic basin, whereas the Masajid Formation was deposited under distal, dysoxic to anoxic basinal or proximal, suboxic to anoxic shelf conditions. In summary, it is concluded that the Late Jurassic and Early Cretaceous witnessed deposition of gas-prone source rocks similar to those found in the southern onshore Nile Delta Basin. The results have significant implications for the understanding of the source rock types in the northern onshore and offshore Egyptian basins and the future of the gas exploration.Elkhoury, J.E., Shankar, R., Ramakrishnan, T.S., 2019. Resolution and limitations of X-Ray micro-CT with applications to sandstones and limestones. Transport in Porous Media 129, 413-425. microtomography (μCT) scanning provides high-resolution images in applications ranging from medical to material sciences and failure analysis. In general, CT scanning relies on X-ray absorption to produce a 3D computed image of the material. In Earth Sciences, μCT scans are used to characterize porosity and pore size, shape and topology of rock samples. For sufficiently large pore systems, the resulting segmented images may be used for quantitative transport calculations. In this note, we infer the limitations of μCT images of rock samples, caused by attainable resolution for a representative sample size. To this end, (1) we perform a systematic analysis with the aid of a resolution chart, (2) we present example scans of an Indiana limestone and a Berea sandstone mini-cores, and (3) we process and analyze the images to extract pore structures using different segmentation algorithms. Porosity estimates inferred from μCT images tend to be lower than bulk measurements.Elwegaa, K., Emadi, H., 2019. Improving oil recovery from shale oil reservoirs using cyclic cold nitrogen injection – An experimental study. Fuel 254, 115716. this experimental study, effects of injecting temperature and pressure on oil recovery factor (RF) of shale oil reservoir was investigated by implementing cyclic cold nitrogen injection on Eagle Ford core samples.Four outcrop core samples from Eagle Ford were used in this study. Nitrogen was injected at various temperatures (?26?°C (?15?°F), ?18?°C (0?°F), 0?°C (32?°F), and 23?°C (74?°F)) and pressures (6.9?MPa (1000?psi), 10.3?MPa (1500?psi), 13.8?MPa (2000?psi), and 20.7?MPa (3000?psi)) into the saturated core samples. Oil recovery factor for each experiment was calculated during three days of production period. Using average Young’s modulus and Poisson’s ratio of the samples, applied thermal stress due to the thermal shock was calculated. Furthermore, Computed Tomography (CT) scanner was deployed to scan the core samples prior to and after performing the experiment.The results demonstrated that injecting nitrogen at low temperatures increases oil RF than does injecting nitrogen at ambient temperature. Injecting cold gas resulted in increase in the cumulative oil recovery factor by 10% and the highest recovery factor was observed at the operating pressure and temperature of 20.7?MPa (3000?psi) and ?26?°C (?15?°F), respectively. The results demonstrated that thermal stress applied to the core samples owing to injecting cold nitrogen resulted in creating new cracks and/or extending the existing ones. Additionally, the results demonstrate that injecting cold nitrogen resulted in widening the existing crack in the core samples. Hence, implementing cyclic cold nitrogen injection could potentially improve the efficacy of the current industry practice of cyclic gas injection technique in shale oil reservoirs.Enriquez, J.E., Siemion, A., Dana, R., Croft, S., Méndez, A., Xu, A., DeBoer, D., Gajjar, V., Hellbourg, G., Isaacson, H., Lebofsky, M., MacMahon, D.H.E., Price, D.C., Werthimer, D., Zuluaga, J., 2019. Breakthrough Listen follow-up of the reported transient signal observed at the Arecibo Telescope in the direction of Ross 128. International Journal of Astrobiology 18, 33-35. undertook observations with the Green Bank Telescope, simultaneously with the 300 m telescope in Arecibo, as a follow-up of a possible flare of radio emission from Ross 128. We report here the non-detections from the GBT observations in C band (4–8 GHz), as well as non-detections in archival data at L band (1.1–1.9 GHz). We suggest that a likely scenario is that the emission comes from one or more satellites passing through the same region of the sky.Ertug, K., Vecoli, M., ?nan, S., 2019. Palynofacies, paleoenvironment and thermal maturity of early Silurian shales in Saudi Arabia (Qusaiba Member of Qalibah Formation). Review of Palaeobotany and Palynology 270, 8-18. early Silurian Qusaiba Shales are proven source rocks of the many Paleozoic petroleum systems of Saudi Arabia. In this study, a new, simple and cost-effective method for semi-quantitative analysis and graphical representation of palynological assemblage composition (PZC Phytoplankton–Zooplankton–Cryptospore ternary diagram) and a new visual thermal alteration index (IPA–TAI Integrated Palynomorph–Amorphous organic matter Thermal Alteration Index) integrating amorphous organic matter and palynomorph color, were developed based on the palynological/palynofacies analysis of some selected wells penetrating the early Silurian Qusaiba Shales throughout Saudi Arabia. The methods were tested against independent paleoenvironmental and thermal maturity indicators mainly based on geochemical parameters, confirming their validity as effective alternative methods for optical kerogen analysis and interpretation. The thermal maturity values estimated for core samples in the Qusaiba Shales from 13 wells in Saudi Arabia showed a strong correlation with Vitrinite Reflectance Equivalent (VRE%) maturity values determined from graptolite reflectance and pyrolysis Tmax measurements in the entire range of maturities (immature to overmature stages), proving that the present visual thermal alteration index can be successfully employed as a time efficient and reliable method for estimating thermal maturity in the Qusaiba Shales of Saudi Arabia. The present results show that the Qusaiba Shales were deposited in mostly mid- to outer shelf, and occasionally nearshore marine environments under prevailing dysoxic and anoxic water conditions, resulting in accumulation and preservation of organic matter.Faber, A.-H., Annevelink, M.P.J.A., Schot, P.P., Baken, K.A., Schriks, M., Emke, E., de Voogt, P., van Wezel, A.P., 2019. Chemical and bioassay assessment of waters related to hydraulic fracturing at a tight gas production site. Science of The Total Environment 690, 636-646. available chemical assessments of hydraulic fracturing related waters are generally based on shale gas practices in the U.S. There is a lack of information on hydraulic fracturing related gas development from EU countries and more generally on other types of extractions. This research fills this knowledge gap by presenting chemical and bioassay assessments of hydraulic fracturing related waters from a tight gas development in the Netherlands. Fracturing fluid, flowback water and groundwater from surrounding aquifers before and after the actual fracturing were analysed by means of high resolution liquid chromatography tandem mass spectrometry, the Ames test and three chemical activated luciferase gene expression bioassays aimed at determining genotoxicity, oxidative stress response and polyaromatic hydrocarbon contamination.After sample enrichment a higher number of peaks can be found in both fracturing fluid and flowback samples. No clear differences in chemical composition were shown in the groundwater samples before and after hydraulic fracturing. Preliminary environmental fate data of the tentatively identified chemicals points towards persistence in water. Clear genotoxic and oxidative stress responses were found in the fracturing fluid and flowback samples. A preliminary suspect screening resulted in 25 and 36 matches in positive and negative ionisation respectively with the 338 possible suspect candidates on the list.Extensive measures relating to the handling, transport and treatment of hydraulic fracturing related waters are currently in place within the Dutch context. The results of the present study provide a scientific justification for such measures taken to avoid adverse environmental and human health impacts.Falk, N., Reid, T., Skoyles, A., Grgicak-Mannion, A., Drouillard, K., Weisener, C.G., 2019. Microbial metatranscriptomic investigations across contaminant gradients of the Detroit River. Science of The Total Environment 690, 121-131. community function in freshwater sediments is influenced by the presence and persistence of anthropogenic pollutants, yet simultaneously imposes significant control on their transformation. Thus, microbes provide valuable ecosystem services in terms of biodegradation and bioindicators of compromised habitats. From a remediation perspective it is valuable to leverage the suite of microbial genes at the transcriptional level that are active in either natural versus stressed environments to provide insight into the cycling and fate of contaminants. Metatranscriptomic analysis of total bacterial and archaeal messenger RNA (mRNA) is a useful tool in this facet and was applied to sediments sampled from the Detroit River; a binational Area of Concern (AOC) in the Great Lakes. Previously established sediment surveys and modelling delineated the river into contaminant gradients based on concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and metals. Differential expression analysis through DESeq2 revealed that microbial transcripts associated with nitrate reduction, methanogenesis, and beta-oxidation were significant in legacy polluted sediments and linked with energetic pathways key in the generation of cellular currencies (acetyl-CoA, succinyl-CoA). Gluconeogenesis and polyester synthesis also showed high abundance in contaminated regions, along with increased expression of stress response genes and transposons, despite decreases in community α-diversity. Aromatic cleavage genes were detected, but in low abundance across the contaminant gradient. These results suggest that microbial communities within the Detroit River exploit unique anabolic and catabolic pathways to derive and store energy from legacy organic contaminants while simultaneously recruiting stress-response and gene transfer mechanisms to cope with xenobiotic pressures. By coupling well-resolved chemical datasets with metatranscriptomics, this study adds to the spatial understanding of in-situ microbial activities in pristine and perturbed freshwater sediments.Falótico, T., Proffitt, T., Ottoni, E.B., Staff, R.A., Haslam, M., 2019. Three thousand years of wild capuchin stone tool use. Nature Ecology & Evolution 3, 1034-1038. human archaeological record changes over time. Finding such change in other animals requires similar evidence, namely, a long-term sequence of material culture. Here, we apply archaeological excavation, dating and analytical techniques to a wild capuchin monkey (Sapajus libidinosus) site in Serra da Capivara National Park, Brazil. We identify monkey stone tools between 2,400 and 3,000?years old and, on the basis of metric and damage patterns, demonstrate that capuchin food processing changed between ~2,400 and 300 years ago, and between ~100 years ago and the present day. We present the first example of long-term tool-use variation outside of the human lineage, and discuss possible mechanisms of extended behavioural change.Fan, C., Zhong, C., Zhang, Y., Qin, Q., He, S., 2019. Geological factors controlling the accumulation and high yield of marine-facies shale gas: Case study of the Wufeng-Longmaxi Formation in the Dingshan area of southeast Sichuan, China. Acta Geologica Sinica - English Edition 93, 536-560. study, the Wufeng‐Longmaxi Formation in the Dingshan area of southeast Sichuan was investigated. Shale cores underwent laboratory testing, which included the evaluation of total organic carbon (TOC), vitrinite reflectance (Ro), whole‐rock X‐ray diffraction (XRD), pore permeability, and imaging through field emission scanning electron microscopy (FE‐SEM). Based on the results of natural gamma ray spectrum logging, conventional logging, imaging logging, and seismic coherence properties, the exploration and development potential of shale gas in the Dingshan area have been discussed comprehensively. The results showed that (1) layer No. 4 (WF2‐LM4) of the Wufeng‐Longmaxi Formation has a Th/U ratio <2 and a Th/K ratio of 3.5‐12. Graptolites and pyrite are relatively abundant in the shale core, indicating sub‐high‐energy and low‐energy marine‐facies anoxic reducing environments. (2) The organic matter is mainly I‐type kerogen with a small amount of II1‐type kerogen. There is a good correlation among TOC, Ro, gas content, and brittle minerals; the fracturing property (brittleness) is 57.3%. Organic and inorganic pores are moderately developed. A higher pressure coefficient is correlated with the increase in porosity and the decrease in permeability. (3) The DY1 well of the shale gas reservoir was affected by natural defects and important late‐stage double destructive effects, and it is poorly preserved. The DY2 well is located far from the Qiyueshan Fault. Large faults are absent, and upward fractures in the Longmaxi Formation are poorly developed. The well is affected by low tectonic deformation intensity, and it is well preserved. (4) The Dingshan area is located at the junction of the two sedimentary centers of Jiaoshiba and Changning. The thickness of the high‐quality shale interval (WF2‐LM4) is relatively small, which may be an important reason for the unstable production of shale gas thus far. Based on the systematic analysis of the geological factors controlling high‐yield shale gas enrichment in the Dingshan area, and the comparative analysis with the surrounding typical exploration areas, the geological understanding of marine shale gas enrichment in southern China has been improved. Therefore, this study can provide a useful reference for shale gas exploration and further development.Fang, X.-M., Zhang, T., Li, J., Wang, N.-F., Wang, Z., Yu, L.-Y., 2019. Bacterial community pattern along the sediment seafloor of the Arctic fjorden (Kongsfjorden, Svalbard). Antonie van Leeuwenhoek 112, 1121-1136. Arctic region has been the focus of increasing attention as an ecosystem that is highly sensitive to changes associated with global warming. Although it was assumed to be vulnerable to changes in climate, a limited number of studies have been conducted on the surface sediment bacteria of Arctic fjorden. This study assessed the diversity and distribution pattern of bacterial communities in eight marine sediments along the seafloor in a high Arctic fjorden (Kongsfjorden, Svalbard). A total of 822 operational taxonomic units (OTUs) were identified by Illumina MiSeq sequencing, targeting the V3–V4 hypervariable regions of the 16S rRNA gene. In these surface marine sediments, more than half of the sequences belonged to the phylum Proteobacteria, followed by Bacteroidetes, Verrucomicrobia, Actinobacteria, Chloroflexi and Lentisphaerae. The bacterial genera Marinicella, Desulfobulbus, Lutimonas, Sulfurovum and clade SEEP-SRB4 were dominant in all samples. Analysis of similarity indicated that bacterial communities were significantly different among the inner, central and outer basins (r2?=?0.5, P?=?0.03?<?0.05). Canonical correspondence analysis and permutation tests revealed that location depth (r2?=?0.87, P?<?0.01), temperature (r2?=?0.88, P?<?0.01) and salinity (r2?=?0.88, P?<?0.05) were the most significant factors that correlated with the bacterial communities in the sediments. 28 differentially abundant taxonomic clades in the inner and outer basin with an LDA score higher than 2.0 were found by the LEfSe method. The Spearman correlation heat map revealed different degrees of correlation between most major OTUs and environmental factors, while some clades have an inverse correlation with environmental factors. The spatial patterns of bacterial communities along the Kongsfjorden may offer insight into the ecological responses of prokaryotes to climate change in the Arctic ecosystem, which makes it necessary to continue with monitoring.Faraji, M., Yamini, Y., Gholami, M., 2019. Recent advances and trends in applications of solid-phase extraction techniques in food and environmental analysis. Chromatographia 82, 1207-1249. paper presents an overview of the more recent applications of solid-phase extraction (SPE, from January 2015 to September 2018, which have been recorded in Web of Science) in preparation of food and environmental samples. First, the history, milestones, principles, and features of different formats of SPE are discussed. In addition, miniaturization of SPE techniques and comparison of classical SPE and miniaturized SPE—called dispersive micro solid-phase extraction (D-μ-SPE)—are covered. Next, the published applications in extraction and separation of diverse organic and inorganic analytes from a variety of food and environmental samples are classified on the basis of their sorbents including layered double hydroxide, metal organic frameworks, carbon nanotube-based sorbents, graphene-based sorbents, β-cyclodextrin-based sorbents, dendrimer-based sorbents, molecular or ion recognition sorbents, and restricted access materials. Finally, the future trends in this area are discussed.Fatayer, S., Albrecht, F., Zhang, Y., Urbonas, D., Pe?a, D., Moll, N., Gross, L., 2019. Molecular structure elucidation with charge-state control. Science 365, 142-145.: The charge state of a molecule governs its physicochemical properties, such as conformation, reactivity, and aromaticity, with implications for on-surface synthesis, catalysis, photoconversion, and applications in molecular electronics. On insulating, multilayer sodium chloride (NaCl) films, we controlled the charge state of organic molecules and resolved their structures in neutral, cationic, anionic, and dianionic states by atomic force microscopy, obtaining atomic resolution and bond-order discrimination using carbon monoxide (CO)–functionalized tips. We detected changes in conformation, adsorption geometry, and bond-order relations for azobenzene, tetracyanoquinodimethane, and pentacene in multiple charge states. Moreover, for porphine, we investigate the charge state–dependent change of aromaticity and conjugation pathway in the macrocycle. This work opens the way to studying chemical-structural changes of individual molecules for a wide range of charge states.Editor's Summary: Visualizing molecular charging. High-resolution atomic force microscopy (AFM) has been used to control and image the charge state of organic molecules adsorbed on multilayer sodium chloride films. Fatayer et al. biased an AFM probe tip with a voltage to charge and discharge molecules such as azobenzene and porphine from cations to anions. Subsequent imaging with carbon monoxide–functionalized tips revealed changes in the conformation, bond order, and aromaticity of the organic molecules resulting from charge-state changes.Fatichi, S., Manzoni, S., Or, D., Paschalis, A., 2019. A mechanistic model of microbially mediated soil biogeochemical processes: A reality check. Global Biogeochemical Cycles 33, 620-648. gaps in the representation of key soil biogeochemical processes such as the partitioning of soil organic carbon among functional components, microbial biomass and diversity, and the coupling of carbon and nutrient cycles present a challenge to improving the reliability of projected soil carbon dynamics. We introduce a new soil biogeochemistry module linked with a well-tested terrestrial biosphere model T&C. The module explicitly distinguishes functional soil organic carbon components. Extracellular enzymes and microbial pools are differentiated based on the functional roles of bacteria, saprotrophic, and mycorrhizal fungi. Soil macrofauna is also represented. The model resolves the cycles of nitrogen, phosphorus, and potassium. Model simulations for 20 sites compared favorably with global patterns of litter and soil stoichiometry, microbial and macrofaunal biomass relations with soil organic carbon, soil respiration, and nutrient mineralization rates. Long-term responses to bare fallow and nitrogen addition experiments were also in agreement with observations. Some discrepancies between predictions and observations are appreciable in the response to litter manipulation. Upon successful model reproduction of observed general trends, we assessed patterns associated with the carbon cycle that were challenging to address empirically. Despite large site-to-site variability, fine root, fungal, bacteria, and macrofaunal respiration account for 33%, 40%, 24%, and 3% on average of total belowground respiration, respectively. Simulated root exudation and carbon export to mycorrhizal fungi represent on average about 13% of plant net primary productivity. These results offer mechanistic and general estimates of microbial biomass and its contribution to respiration fluxes and to soil organic matter dynamics.Faust, J.C., Knies, J., 2019. Organic matter sources in North Atlantic fjord sediments. Geochemistry, Geophysics, Geosystems 20, 2872-2885. To better constrain the global carbon cycle fundamental knowledge of the role of carbon cycling on continental margins is crucial. Fjords are particularly important shelf areas for carbon burial due to relatively high sedimentation rates and high organic matter fluxes. As terrigenous organic matter is more resistant to remineralization than marine organic matter, a comprehensive knowledge of the carbon source is critical to better constrain the efficiency of organic carbon burial in fjord sediments. Here we investigated highly productive fjords in northern Norway and compare our results with both existing and new organic carbon to organic nitrogen ratios and carbon stable isotope compositions from fjords in mid-Norway, west Svalbard, and east Greenland. The marine organic carbon contribution varies significantly between these fjords, and the contribution of marine organic carbon in Norwegian fjords is much larger than previously suggested for fjords in NW Europe and also globally. Additionally, northern Norwegian fjords show very high marine carbon burial rates (73.6 gC · m-2 · year-1) suggesting that these fjords are probably very distinct carbon burial hotspots. We argue that the North Atlantic Current inflow sustains these high burial rates and changes in the current strength due to ongoing climate change are likely to have a pronounced effect on carbon burial in North Atlantic fjords.Feldman, M., Master, D.M., Bianco, R.A., Burri, M., Stockhammer, P.W., Mittnik, A., Aja, A.J., Jeong, C., Krause, J., 2019. Ancient DNA sheds light on the genetic origins of early Iron Age Philistines. Science Advances 5, eaax0061. ancient Mediterranean port city of Ashkelon, identified as “Philistine” during the Iron Age, underwent a marked cultural change between the Late Bronze and the early Iron Age. It has been long debated whether this change was driven by a substantial movement of people, possibly linked to a larger migration of the so-called “Sea Peoples.” Here, we report genome-wide data of 10 Bronze and Iron Age individuals from Ashkelon. We find that the early Iron Age population was genetically distinct due to a European-related admixture. This genetic signal is no longer detectible in the later Iron Age population. Our results support that a migration event occurred during the Bronze to Iron Age transition in Ashkelon but did not leave a long-lasting genetic signature.Féraud, G., Bertin, M., Romanzin, C., Dupuy, R., Le Petit, F., Roueff, E., Philippe, L., Michaut, X., Jeseck, P., Fillion, J.-H., 2019. Vacuum ultraviolet photodesorption and photofragmentation of formaldehyde-containing ices. ACS Earth and Space Chemistry 3, 1135-1150. desorption from icy grains containing H2CO has been invoked to explain the observed H2CO gas phase abundances in protoplanetary disks (PPDs) and photon dominated regions (PDRs). Photodesorption is thought to play a key role; however, no absolute measurement of the photodesorption from H2CO ices was performed up to now, so that a default value is used in the current astrophysical models. As photodesorption yields differ from one molecule to the other, it is crucial to experimentally investigate photodesorption from H2CO ices. We measured absolute wavelength-resolved photodesorption yields from pure H2CO ices, H2CO on top of a CO ice (H2CO/CO), and H2CO mixed with CO ice (H2CO:CO) irradiated in the vacuum ultraviolet (VUV) range (7–13.6 eV). Photodesorption from a pure H2CO ice releases H2CO in the gas phase but also fragments, such as CO and H2. Energy-resolved photodesorption spectra, coupled with infrared (IR) and temperature-programmed desorption (TPD) diagnostics, showed the important role played by photodissociation and allowed discussion of photodesorption mechanisms. For the release of H2CO in the gas phase, they include desorption induced by electronic transitions (DIET), indirect DIET through CO-induced desorption of H2CO, and photochemical desorption. We found that H2CO photodesorbs with an average efficiency of ～(4–10) × 10–4 molecule/photon, in various astrophysical environments. H2CO and CO photodesorption yields and photodesorption mechanisms, involving photofragmentation of H2CO, can be implemented in astrochemical codes. The effects of photodesorption on gas/solid abundances of H2CO and all linked species from CO to complex organic molecules (COMs), and on the H2CO snowline location, are now on the verge of being unravelled.Ferey, J., Marguet, F., Laquerrière, A., Marret, S., Schmitz-Afonso, I., Bekri, S., Afonso, C., Tebani, A., 2019. A new optimization strategy for MALDI FTICR MS tissue analysis for untargeted metabolomics using experimental design and data modeling. Analytical and Bioanalytical Chemistry 411, 3891-3903. imaging mass spectrometry using matrix-assisted laser desorption ionization (MALDI) MS coupled to a Fourier transform ion cyclotron resonance (FTICR) mass analyzer is a powerful technique for the visualization of small molecule distribution within biological tissues. The FTICR MS provides ultra-high resolving power and mass accuracy that allows large molecular coverage and molecular formula assignments, both essential for untargeted metabolomics analysis. These performances require fine optimizations of the MALDI FTICR parameters. In this context, this study proposes a new strategy, using experimental design, for the optimization of ion transmission voltages and MALDI parameters, for tissue untargeted metabolomics analysis, in both positive and negative ionization modes. These experiments were conducted by assessing the effects of nine factors for ion transmission voltages and four factors for MALDI on the number of peaks, the weighted resolution, and the mean error within m/z 150–1000 mass range. For this purpose, fractional factorial designs were used with multiple linear regression (MLR) to evaluate factor effects and to optimize parameter values. The optimized values of ion transmission voltages (RF amplitude TOF, RF amplitude octopole, frequency transfer optic, RF frequency octopole, deflector plate, funnel 1, skimmer, funnel RF amplitude, time-of-flight, capillary exit), MALDI parameters (laser fluence, number of laser shots), and detection parameters (data size, number of scans) led to an increase of 32% and 18% of the number of peaks, an increase of 8% and 39% of the resolution, and a decrease of 56% and 34% of the mean error in positive and negative ionization modes, respectively.Fernández-Martínez, M.?., dos Santos Severino, R., Moreno-Paz, M., Gallardo-Carre?o, I., Blanco, Y., Warren-Rhodes, K., García-Villadangos, M., Ruiz-Bermejo, M., Barberán, A., Wettergreen, D., Cabrol, N., Parro, V., 2019. Prokaryotic community structure and metabolisms in shallow subsurface of Atacama Desert playas and alluvial fans after heavy rains: Repairing and preparing for next dry period. Frontiers in Microbiology 10, 1641. doi: 10.3389/fmicb.2019.01641. Desert, the oldest and driest desert on Earth, displays significant rains only once per decade. To investigate how the microbial communities take advantage of these wet events, we carried out a geomicrobiological study few days after a heavy rain event in 2015. Different physicochemical and microbial community analyses were conducted on samples collected from playas and an alluvial fan from surface, 10, 20, 50 and 80 cm depth. A water content peaks were measured in 10 and 20 cm depth samples (from 1.65% to 4.1% w/w maximum values) while, in general, main anions such as chloride, nitrate, and sulphate concentrations increased with depth with maximum values of 13 to 1125 ppm, 168 to 10,109 ppm and 9,904 to 30,952 ppm, respectively. Small organic anions such as formate and acetate were also measured with maximum concentrations from 2.61 to 3.44 pm and 6.73 to 28.75 ppm, respectively. Microbial diversity inferred from DNA analysis showed Actinobacteria and Alphaproteobacteria as the most abundant and widespread bacterial taxa among the samples, followed by Chloroflexi and Firmicutes at specific sites. Archaea were mainly dominated by Nitrososphaerales, Methanobacteria, with the detection of other groups such as Halobacteria. Metaproteomics showed a high and even distribution of proteins involved in primary metabolic processes such as energy production and biosynthetic pathways, and a limited but remarkable presence of proteins related to resistance to environmental stressors such as radiation, oxidation, or desiccation. The results indicated that extra humidity in the system allows the microbial community to repair, grow, and prepare for the upcoming hyperarid period. Additionally, it supplies biomarkers to the medium whose preservation potential could be high under strong desiccation conditions and relevant for planetary exploration.Findlay, A.J., Boyko, V., Pellerin, A., Avetisyan, K., Guo, Q., Yang, X., Kamyshny Jr., A., 2019. Sulfide oxidation affects the preservation of sulfur isotope signals. Geology 47, 739-743. accumulation of oxygen in Earth’s atmosphere and oceans in the late Archean had profound implications for the planet’s biogeochemical evolution. Oxygen impacts sulfur cycling through the oxidation of sulfide minerals and the production of sulfate for microbial sulfate reduction (MSR). The isotopic signature of sulfur species preserved in the geologic record is affected by the prevailing biological and chemical processes and can therefore be used to constrain past oxygen and sulfate concentrations. Here, in a study of a late Archean analogue, we find that the sulfur isotopic signature in the water column of a seasonally stratified lake in southern China is influenced by MSR, whereas model results indicate that the isotopic signature of the underlying sediments can be best explained by concurrent sulfate reduction and sulfide oxidation. These data demonstrate that small apparent sulfur isotope fractionations (δ34Ssulfate-AVS = 4.2‰–1.5‰; AVS—acid volatile sulfides) can be caused by dynamic sulfur cycling at millimolar sulfate concentrations. This is in contrast to current interpretations of the isotopic record and indicates that small fractionations do not necessarily indicate very low sulfate or oxygen.Forde, O.N., Cahill, A.G., Mayer, K.U., Mayer, B., Simister, R.L., Finke, N., Crowe, S.A., Cherry, J.A., Parker, B.L., 2019. Hydro-biogeochemical impacts of fugitive methane on a shallow unconfined aquifer. Science of The Total Environment 690, 1342-1354. and gas development can result in natural gas migration into shallow groundwater. Methane (CH4), the primary component of natural gas, can subsequently react with solutes and minerals in the aquifer to create byproducts that affect groundwater chemistry. Hydro-biogeochemical processes induced by fugitive gas from leaky oil and gas wells are currently not well understood. We monitored the hydro-biogeochemical responses of a controlled natural gas release into a well-studied Pleistocene beach sand aquifer (Canadian Forces Base Borden, Ontario, Canada). Groundwater samples were collected before, during, and up to 700?days after gas injection and analyzed for pH, major and minor ions, alkalinity, dissolved gases, stable carbon isotope ratios of CO2 and CH4, and microbial community composition. Gas injection resulted in a dispersed plume of free and dissolved phase natural gas, affecting groundwater chemistry in two distinct temporal phases. Initially (i.e. during and immediately after gas injection), pH declined and major ions and trace elements fluctuated; at times increasing above baseline concentrations. Changes in the short-term were due to invasion of deep groundwater with elevated total dissolved solids entrained with the upward migration of free phase gas and, reactions that were instigated through the introduction of constituents other than CH4 present in the injected gas (e.g. CO2). At later times, more pronounced aerobic and anaerobic CH4 oxidation led to subtle increases in major ions (e.g. Ca2+, H4SiO4) and trace elements (e.g. As, Cr). Microbial community profiling indicated a persistent perturbation to community composition with a conspicuous ingrowth of taxa implicated in aerobic CH4 oxidation as well anaerobic S, N and Fe species metabolism.Forgan, D., Wright, J., Tarter, J., Korpela, E., Siemion, A., Almár, I., Piotelat, E., 2019. Rio 2.0: revising the Rio scale for SETI detections. International Journal of Astrobiology 18, 336-344. Rio scale is a tool for communicating the significance of a signal to the general public. It assigns scores to signals detected in searches for extraterrestrial intelligence (SETI), which characterizes both the consequences of a signal and the probability the signal is truly from ETI, in an easily digestible format for laypeople to interpret. In the 17 years since its construction, the number of groups actively conducting searches for evidence of intelligent life beyond the Earth has increased significantly, and theoretical work has established a new suite of observables that are capable of revealing the presence of ETI in a range of astronomical observations. In this paper, we revise the Rio scale, with the aim of (i) achieving consensus across academic disciplines on a scheme for classifying signals potentially indicating the existence of advanced extraterrestrial life, (ii) supplying a pedagogical tool to help inform the public about the process scientists go through to develop an understanding of a signal and (iii) providing a means of calibrating the expectations of the world at large when signals are discussed in the media. We also present (and encourage the SETI community to adopt) a single set of consistent terminology for discussing signals.Forgan, D.H., 2019. Exoplanet transits as the foundation of an interstellar communications network. International Journal of Astrobiology 18, 189-198. fundamental problems for extraterrestrial intelligences (ETIs) attempting to establish interstellar communication are timing and energy consumption. Humanity's study of exoplanets via their transit across the host star highlights a means of solving both problems. An ETI ‘A’ can communicate with ETI ‘B’ if B is observing transiting planets in A's star system, either by building structures to produce artificial transits observable by B, or by emitting signals at B during transit, at significantly lower energy consumption than typical electromagnetic transmission schemes. This can produce a network of interconnected civilizations, establishing contact via observing each other's transits. Assuming that civilizations reside in a Galactic Habitable Zone (GHZ), I conduct Monte Carlo Realization simulations of the establishment and growth of this network, and analyse its properties in the context of graph theory. I find that at any instant, only a few civilizations are correctly aligned to communicate via transits. However, we should expect the true network to be cumulative, where a ‘handshake’ connection at any time guarantees connection in the future via e.g. electromagnetic signals. In all our simulations, the cumulative network connects all civilizations together in a complete network. If civilizations share knowledge of their network connections, the network can be fully complete on timescales of order a hundred thousand years. Once established, this network can connect any two civilizations either directly, or via intermediate civilizations, with a path much less than the dimensions of the GHZ.Fox, S., Pleyer, H.L., Strasdeit, H., 2019. An automated apparatus for the simulation of prebiotic wet?dry cycles under strictly anaerobic conditions. International Journal of Astrobiology 18, 60-72. chemical evolution on the early Earth may have been driven in part by fluctuating environments, for example wet?dry and temperature cycling in volcanic rock pools. Here, we describe the setup, operating principle and test applications of a newly developed ‘wet?dry apparatus’ (WDA) designed to simulate such fluctuating environments. The WDA allows adjusting the duration of the cycles, the temperature during the wet and dry phases and the organic and mineral components, which are all key parameters in wet–dry simulations. The WDA's most important features, however, are (i) that it is automated, which means that long-time experiments are possible without the need for an operator and (ii) that the virtual absence of free oxygen in the early Earth's atmosphere at ground level can be simulated. Rigorously oxygen-free conditions were achieved by passing 99.999% nitrogen gas through two alkaline pyrogallol solutions in series, prior to entering the WDA. We used three chemical systems to test the WDA: (i) the amino acid glycine in the presence and absence of clay minerals, (ii) linoleic acid (an oxygen-sensitive amphiphile) with and without the mineral olivine, and (iii) alkaline pyrogallol solution. We observed that clay minerals greatly accelerated the decomposition of glycine under wet?dry conditions. Glycine peptides were formed as minor products. In the course of the glycine experiments, we developed a reliable gas chromatographic method to quantify the cyclic dipeptide 2,5-diketopiperazine. The decomposition of linoleic acid in wet?dry cycles was promoted by both air and olivine. And finally, the extremely oxygen-sensitive pyrogallol solution was used as a colour indicator for residual oxygen in the WDA. The simulation facility in our laboratory currently consists of eight identical WDAs and a surrounding infrastructure. It can be made available to others who wish to perform cyclic wet–dry experiments.Freissinet, C., Millan, M., Glavin, D.P., Li, X., Grubisic, A., Eigenbrode, J.E., Stern, J.C., Dworkin, J.P., Buch, A., Szopa, C., Guzman, M.A., Carts, M.A., Getty, S.A., Brinckerhoff, W.B., 2019. Investigating the effects of gamma radiation on selected chemicals for use in biosignature detection instruments on the surface of Jupiter's moon Europa. Planetary and Space Science 175, 1-12.'s moon Europa is a prime target for the search for potential signs of life in the solar system. The Europa Lander Science Definition Team Report outlined investigations and measurement requirements on a future Europa Lander and has led us to consider application of powerful techniques such as pyrolysis and derivatization gas chromatography mass spectrometry (GC-MS) and laser desorption mass spectrometry (LD-MS) to elucidate the organic composition of near-surface ice and minerals. Definitive identification of chemical biosignatures using such techniques is strongly enabled by the use of various chemicals, such as perfluorotributylamine (PFTBA) for the MS calibration, α-cyano-hydroxycinnamic acid (CHCA) for matrix-assisted laser desorption and ionization (MALDI) and N,N-dimethylformamide dimethyl acetal (DMF-DMA), N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA) and tetramethylammonium hydroxide (TMAH) for wet chemistry GC-MS protocols. The jovian radiation environment is known to represent a uniquely challenging risk to mission performance and lifetime, principally due to high radiation levels. To assess the potential ionizing radiation damage to these important chemicals, we tested their effectiveness following gamma radiation exposure doses up to the anticipated Europa Lander rating requirement of 300?krad(Si). The chemicals were sealed in glass ampules under vacuum (<10 mTorr), to reduce trapped oxygen gas, as the oxidation by O2 may be enhanced in the presence of radiation. We report that all five chemicals exposed to total ionizing doses of 0, 150 and 300?krad(Si) maintained their full effectiveness, and no significant degradation was observed.French-McCay, D., Crowley, D., McStay, L., 2019. Sensitivity of modeled oil fate and exposure from a subsea blowout to oil droplet sizes, depth, dispersant use, and degradation rates. Marine Pollution Bulletin 146, 779-793. part of a Comparative Risk Assessment (CRA) developed and reported previously, oil spill modeling of a hypothetical blowout at 1400?m in the northeastern Gulf of Mexico was performed to evaluate changes in oil exposures with alternative response options, i.e., combinations of mechanical recovery, in-situ burning, surface dispersant application and subsea dispersant injection (SSDI). To assess if conclusions from this study could be extended to other spill scenarios, sensitivities of the predicted oil fate and exposure metrics to location, release depth, oil and gas flow rate, gas content, orifice size, oil droplet size distribution, and biodegradation rates were examined. Results show that the fraction of oil surfacing is highly sensitive to oil droplet size distribution and depth of release. Across the simulations performed, SSDI use reduced oil droplet sizes released, thereby mitigating surface and shoreline oiling, volatile hydrocarbon exposures, and potential surface water column exposures.Fu, Y., Jiang, Y., Wang, Z., Hu, Q., Xie, J., Ni, G., Lei, Z., Zhou, K., Liu, X., 2019. Non-connected pores of the Longmaxi shale in southern Sichuan Basin of China. Marine and Petroleum Geology 110, 420-433. characteristics of non-connected pores of four Longmaxi shale samples from the southern Sichuan Basin of China were investigated from the studies of pore size distribution (PSD), pore volumes, pore types using helium pycnometry [gas injection porosimetry (GIP) and GRI (Gas Research Institute) method], nuclear magnetic resonance (NMR), nuclear magnetic resonance cryoporometry (NMRc), and spontaneous water and oil imbibition experiments. GRI porosity on particle sizes less than 5?mm sample and a 2?MPa helium injection pressure provides information on the total porosity, including both non-connected and connected pores. GIP porosity using core plugs only measures connected pores which extend to the surface of the sample accessible by helium. So the difference between GRI and GIP porosities is used to estimate the volumes of non-connected pores. And the volumes of non-connected pores accounts for 17.5%–40.3% of the total pore volume. For NMRc test results, total pore volume increases with sample size decrease, and the great difference of pore volume with a pore diameter range from 5?nm to 31?nm between small cylinder sample and 0.15–0.075?mm crushed sample is caused by non-connected pores opened. With a decrease of length for cubic samples, the increase in volume and rate of oil imbibition is greater than that of water imbibition, indicating that the non-connected pores are considered to be mainly oil-wet. In addition, the percentage of non-connected pores has a good correlation with TOC (total organic carbon) content. Therefore, this evidence implies that non-connected pores are mainly within the organic matter. NMR tests at different drying temperatures and a NMRc experiment provide a quantitative classification of the shale pore system which indicates that the exploitable pore diameters are larger than 4.25?nm. So non-connected pores with a diameter of 5–31?nm could be effectively exploited if connected by fracturing. The more the non-connected pores are opened, the better the pore connectivity of shale reservoir will be, with a less possibility of water blocking. In the process of shale gas development, attention should be paid to the interaction between fracturing fluid and rock components in order to release more non-connected pores. Therefore, to increase shale gas extraction efficiency, more effort should be directed towards identifying natural, and creating induced, porosity.Fuchs, S.J., Espinoza, D.N., Lopano, C.L., Akono, A.-T., Werth, C.J., 2019. Geochemical and geomechanical alteration of siliciclastic reservoir rock by supercritical CO2-saturated brine formed during geological carbon sequestration. International Journal of Greenhouse Gas Control 88, 251-260. carbon sequestration (GCS) is an approach for storing CO2 and mitigating greenhouse gas emissions. During GCS, carbon dioxide dissolves into pore water, resulting in a low-pH brine that can react with reservoir rock minerals. This work evaluates the effects of geochemical reactions on geomechanical integrity of representative siliciclastic reservoir samples obtained from the Mt. Simon formation. Rock samples were aged 4 or 8 weeks in CO2-saturated brine under reservoir conditions, and in N2-saturated brine as a control. Post-aging, CT scans revealed more extensive micro-fracture development along horizontal bedding planes at grain edges in CO2 versus N2-aged samples. Digital analysis of CO2-aged samples showed porosity increase from 8.1% to 15.8%. Scanning electron microscopy revealed the loss of clay cementation, greater exposure of quartz and K-feldspar grains, and apparent surface roughening (confirmed by laser profilometry) in CO2-aged samples, but not in N2-aged samples. Fracture toughness as evaluated by scratch testing was reduced by 32.1% after 4 weeks in scCO2-saturated brine and 69.5% after 8 weeks. The primary reason for weakening appears to be detachment of clays from quartz and feldspar grain surfaces, resulting in weakening of the rock matrix. Rock weakening may alter the geomechanical stability of storage formations.Galera, E., Galanti, G.R., Kinouchi, O., 2019. Invasion percolation solves Fermi Paradox but challenges SETI projects. International Journal of Astrobiology 18, 316-322. fractal-like colonization processes, where the cluster of visited sites has large voids and grows slowly, could explain the negative results of Search for Extraterrestrial Intelligence (SETI) preserving the possibility of a galactic spanning civilization. Here we present a generalized invasion percolation model to illustrate a minimal colonization process with large voids and delayed colonization. Spatial correlation between unvisited sites, in the form of large empty regions, suggests that to search civilizations in the Sun neighbourhood may be a misdirected SETI strategy. A weaker form of the Fermi Paradox also suggests this last conclusion.Ganesh Kumar, A., Nivedha Rajan, N., Kirubagaran, R., Dharani, G., 2019. Biodegradation of crude oil using self-immobilized hydrocarbonoclastic deep sea bacterial consortium. Marine Pollution Bulletin 146, 741-750. bacterial consortium that utilizes crude oil as carbon and energy source was isolated from marine sediment collected at a depth of 2100?m. Molecular characterization by 16S rRNA gene sequences confirmed that these isolates as Oceanobacillus sp., Nesiotobacter sp., Ruegeria sp., Photobacterium sp., Enterobacter sp., Haererehalobacter sp., Exiguobacterium sp., Acinetobacter sp. and Pseudoalteromonas sp. Self-immobilized consortium degraded more than 85% of total hydrocarbons after 10?days of incubation with 1% (v/v) of crude oil and 0.05% (v/v) of Tween 80 (non-ionic surfactant) at 28?±?2?°C. The addition of nitrogen and phosphorus sources separately i.e. 0.1% (v/v) of CO (NH2)2 or K2HPO4 enhanced the hydrocarbon utilization percentage. The pathways of microbial degradation of hydrocarbons were confirmed by FTIR, GC–MS, 1H and 13C NMR spectroscopy analyses. These results demonstrated a novel approach using hydrocarbonoclastic self-immobilized deep sea bacterial consortium for eco-friendly bioremediation.Gao, K., Jiang, M., Guo, C., Zeng, Y., Fan, C., Zhang, J., Reinfelder, J.R., Huang, W., Lu, G., Dang, Z., 2019. Reductive dissolution of jarosite by a sulfate reducing bacterial community: Secondary mineralization and microflora development. Science of The Total Environment 690, 1100-1109. is an iron-hydroxysulfate mineral commonly found in acid mine drainage (AMD). Given its strong adsorption capacity and its ability to co-precipitation with heavy metals, jarosite is considered a potent scavenger of contaminants in AMD-impacted environments. Sulfate-reducing bacteria (SRB) play an important role in the reductive dissolution of jarosite; however, the mechanism involved has yet to be elucidated. In this study, an indigenous SRB community enriched from the Dabaoshan mine area (Guangdong, China) was employed to explore the mechanism of the microbial reduction of jarosite. Different cultures, with or without dissolved sulfate and the physical separation of jarosite from bacteria by dialysis bags, were examined. Results indicate that the reduction of jarosite by SRB occurred via an indirect mechanism. In systems with dissolved sulfate, lactate was incompletely oxidized to acetate coupled with the reduction of SO42? to S2?, which subsequently reduced the Fe3+ in jarosite, forming secondary minerals including vivianite, mackinawite and pyrite. In systems without dissolved sulfate, jarosite dissolution occurred prior to reduction, and similar secondary minerals formed as well. Extracellular polymeric substances secreted by SRB appeared to facilitate the release of sulfate from jarosite. Structural sulfate in the solid phase of jarosite may not be available for SRB respiration. Although direct contact between SRB and jarosite is not necessary for mineral reduction, wrapping jarosite into dialysis bags suppressed the reduction to a certain extent. Microbial community composition differed in direct contact treatments and physical separation treatments. Physical separation of the SRB community from jarosite mineral supported the growth of Citrobacter, while Desulfosporosinus dominated in direct contact treatments.Gao, L., Gao, Y., Zong, H., Guo, L., 2019. Elucidating the hidden nonconservative behavior of DOM in large river-dominated estuarine and coastal environments. Journal of Geophysical Research: Oceans 124, 4258-4271. the mixing behavior and biogeochemical cycling of heterogeneous dissolved organic matter (DOM) at the land-ocean interface has been a major challenge, especially in large river-dominated estuarine and coastal environments with multiple and complex end-members of riverwater and seawater. Significant correlations and thus an ?apparent? conservative behavior are generally observed for the bulk DOM when plotting concentration-salinity relationships, but the relatively small deviations from the apparent conservative behavior are difficult to be quantified. In July 2016, the flood in the Changjiang River basin caused the Changjiang Diluted Water extended widely to the western East China Sea, making it a natural laboratory to examine the river-sea mixing behavior of riverine DOM and other optical properties. Here a new biogeochemical approach was established to elucidate their hidden nonconservative behavior in the study area. Comparisons in the bulk dissolved organic carbon and the three chromophoric DOM properties among 13 pairs of same-salinity patches (with similar salinities but quite different distances from the river mouth) revealed that the East China Sea shelf was a significant sink for all the three chromophoric DOM properties. The Changjiang Diluted Water surface branches transporting southward tended to serve as a sink for the bulk dissolved organic carbon while the ones transporting northward were less a sink or even a source. The different removal extents of various biogeochemical constituents can also be calculated from the same-salinity patch comparisons. Our results obtained by the new approach provide detailed magnitudes of sink or source for different DOM properties and their in situ removal/production extents, giving new insights into biogeochemical processes in large river-dominated estuarine and coastal environments.García, R.A., Chiaia-Hernández, A.C., Lara-Martin, P.A., Loos, M., Hollender, J., Oetjen, K., Higgins, C.P., Field, J.A., 2019. Suspect screening of hydrocarbon surfactants in AFFFs and AFFF-contaminated groundwater by high-resolution mass spectrometry. Environmental Science & Technology 53, 8068-8077. film-forming foams (AFFFs) are proprietary mixtures containing hydrocarbon surfactants and per- and polyfluoroalkyl substances (PFASs) that are used to extinguish hydrocarbon-based fuel fires. There is limited information on hydrocarbon surfactants in AFFFs and AFFF-contaminated groundwater even though hydrocarbon surfactants are more abundant (5–10% w/w) than PFASs (0.9–1.5% w/w) in AFFFs. Eight commercial AFFFs manufactured between 1988 and 2012 and 10 AFFF-contaminated groundwaters collected from near source zones of fire-fighter training areas were analyzed for suspect hydrocarbon surfactants by liquid chromatography quadrupole time-of-flight mass spectrometry. A suspect list and a homologous series detection computational tool, enviMass, were combined to screen for hydrocarbon surfactants. Nine classes of hydrocarbon surfactants were detected in AFFFs including octylphenol polyethoxylates, linear alcohol ethoxylates, ethoxylated cocoamines, alkyl ether sulfates, alkyl amido dipropionates, linear alkyl benzenesulfonates, alkyl sulfates, and polyethylene glycols. Of those, six were also found in groundwater along with diethanolamines and alkyl amido betaines, which were not found in the eight archived AFFFs. This indicates that although aerobically biodegradable, hydrocarbon surfactants likely persist in groundwater due to anaerobic aquifer conditions. To the best of our knowledge, this is the first screening for hydrocarbon surfactants in AFFFs and in AFFF-contaminated groundwater.Garrison, C.E., Price, K.A., Field, E.K., 2019. Environmental evidence for and genomic insight into the preference of iron-oxidizing bacteria for more-corrosion-resistant stainless steel at higher salinities. Applied and Environmental Microbiology 85, e00483-19.: Iron-oxidizing bacteria (FeOB) are some of the initial colonizing organisms during microbially influenced corrosion of steel infrastructure. To better understand the abiotic conditions under which FeOB colonize steel, an environmental study was conducted to determine the effects of salinity, temperature, dissolved oxygen levels, and steel type on FeOB colonization. Stainless steel (304 and 316 [i.e., 304SS and 316SS]) was used to determine the potential susceptibility of these specialized corrosion-resistant steels. Steel coupon deployments along salinity gradients in two river systems revealed attachment by FeOB at all sites, with greater abundance of FeOB at higher salinities and on 316SS, compared to 304SS. This may be due to the presence of molybdenum in 316SS, potentially providing a selective advantage for FeOB colonization. A novel Zetaproteobacteria species, Mariprofundus erugo, was isolated from these stainless steel samples. Genes for molybdenum utilization and uptake and reactive oxygen species protection were found within its genome, supporting the evidence from our FeOB abundance data; they may represent adaptations of FeOB for colonization of surfaces of anthropogenic iron sources such as stainless steel. These results reveal environmental conditions under which FeOB colonize steel surfaces most abundantly, and they provide the framework needed to develop biocorrosion prevention strategies for stainless steel infrastructure in coastal estuarine areas.Importance: Colonization of FeOB on corrosion-resistant stainless steel types (304SS and 316SS) has been quantified from environmental deployments along salinity gradients in estuarine environments. Greater FeOB abundance at higher salinities and on the more-corrosion-resistant 316SS suggests that there may be a higher risk of biocorrosion at higher salinities and there may be a selective advantage from certain stainless steel alloy metals, such as molybdenum, for FeOB colonization. A novel species of FeOB described here was isolated from our stainless steel coupon deployments, and its genome sequence supports our environmental data, as genes involved in the potential selectiveness toward surface colonization of stainless steel might lead to higher rates of biocorrosion of manmade aquatic infrastructure. These combined results provide environmental constraints for FeOB colonization on anthropogenic iron sources and build on previous frameworks for biocorrosion prevention strategies.Gawas, V.S., Shivaramu, M.S., Damare, S.R., Pujitha, D., Meena, R.M., Shenoy, B.D., 2019. Diversity and extracellular enzyme activities of heterotrophic bacteria from sediments of the Central Indian Ocean Basin. Scientific Reports 9, 9403. bacteria play a role in polymetallic nodule formation and growth. There are, however, limited reports on bacterial diversity in nodule-rich areas of the Central Indian Ocean Basin (CIOB). In this study, bacterial abundance in thirteen sediment cores collected from the CIOB was enumerated, followed by phylogenetic?characterisation and, screening of select heterotrophic bacteria for extracellular enzyme activities. Total bacterial counts (TBC) were in the order of 107 cells g?1; there was a significant difference (p?>?0.05) among the cores but not within the sub-sections of the cores. The retrievable heterotrophic counts ranged from non-detectable to 5.33?×?105?g?1; the heterotrophic bacteria clustered within the?phyla Firmicutes, Proteobacteria and Actinobacteria. Bacillus was the most abundant genus. The extracellular enzyme activities were in the order: amylase?>?lipase?>?protease?>?phosphatase?>?Dnase?>?urease. Major findings are compared with previous studies from the CIOB and other areas.Gerrish, P.J., Ferreira, C.P., 2019. A thermodynamic limit constrains complexity and primitive social function. International Journal of Astrobiology 18, 329-335. evolutionary trend toward increasing complexity and social function is ultimately the result of natural selection's paradoxical tendency to foster cooperation through competition. Cooperating populations ranging from complex societies to somatic tissue are constantly under attack, however, by non-cooperating mutants or transformants, called ‘cheaters’. Structure in these populations promotes the formation of cooperating clusters whose competitive superiority can alone be sufficient to thwart outgrowths of cheaters and thereby maintain cooperation. But we find that when cheaters appear too frequently – exceeding a threshold mutation or transformation rate – their scattered outgrowths infiltrate and break up cooperating clusters, resulting in a cascading loss of social cohesiveness, a switch to net positive selection for cheaters and ultimately in the loss of cooperation. Our findings imply that a critically low mutation rate had to be achieved (perhaps through the advent of proofreading and repair mechanisms) before complex cooperative functions, such as those required for multicellularity and social behaviour, could have evolved and persisted. When mutation rate in our model is also allowed to evolve, the threshold is crossed spontaneously after thousands of generations, at which point cheaters rapidly invade. Probing extrapolations of these findings suggest: (1) in somatic tissue, it is neither social retro-evolution alone nor mutation rate evolution alone but the interplay between these two that ultimately leads to oncogenic transitions; the rate of this coevolution might thereby provide an indicator of lifespan of species, terrestrial or not; (2) the likelihood that extraterrestrial life can be expected to be multicellular and social should be affected by ultraviolet and other mutagenic factors.Geuer, J.K., Krock, B., Leefmann, T., Koch, B.P., 2019. Quantification, extractability and stability of dissolved domoic acid within marine dissolved organic matter. Marine Chemistry 215, 103669. widespread diatom Pseudo-nitzschia can produce domoic acid (DA). DA is a compound with well described neurotoxic effects on vertebrates including humans known as amnesic shellfish poisoning (ASP) syndrome. It has also been suggested to serve as an organic ligand that binds to iron and copper. By binding these trace elements, DA may increase their solubility and bioavailability. In order to serve this function, DA has to be excreted and reabsorbed by the cells. Only few records of dissolved domoic acid (dDA) concentrations in the ocean exist. To accomplish quantification by ultra performance liquid chromatography (UPLC), samples have to be pre-concentrated and desalted using solid-phase extraction, a procedure commonly applied for dissolved organic matter. Our major goals were to quantify dDA in a basin-wide assessment in the East Atlantic Ocean, to determine extraction efficiencies for complexed and uncomplexed dDA, and to assess whether domoic acid is represented by its molecular formula in direct-infusion high resolution mass spectrometry. Our results showed that dDA was extracted almost quantitatively and occurred ubiquitously in the ocean surface but also in deeper (and older) water, indicating surprisingly high stability in seawater. The maximum concentration measured was 173?pmol?L?1 and the average molar dDA carbon yield was 7.7?ppm. Both carbon yield and dDA concentration decreased with increasing water depth. Providing quantification of dDA in the water column, we seek to improve our understanding of toxic bloom dynamics and the mechanistic understanding of DA production.Giles, K., Ujma, J., Wildgoose, J., Pringle, S., Richardson, K., Langridge, D., Green, M., 2019. A cyclic ion mobility-mass spectrometry system. Analytical Chemistry 91, 8564-8573. in the performance and availability of commercial instrumentation have made ion mobility-mass spectrometry (IM-MS) an increasingly popular approach for the structural analysis of ionic species as well as for separation of complex mixtures. Here, a new research instrument is presented which enables complex experiments, extending the current scope of IM technology. The instrument is based on a Waters SYNAPT G2-Si IM-MS platform, with the IM separation region modified to accept a cyclic ion mobility (cIM) device. The cIM region consists of a 98 cm path length, closed-loop traveling wave (TW)-enabled IM separator positioned orthogonally to the main ion optical axis. A key part of this geometry and its flexibility is the interface between the ion optical axis and the cIM, where a planar array of electrodes provides control over the TW direction and subsequent ion motion. On either side of the array, there are ion guides used for injection, ejection, storage, and activation of ions. In addition to single and multipass separations around the cIM, providing selectable mobility resolution, the instrument design and control software enable a range of “multifunction” experiments such as mobility selection, activation, storage, IMSn, and importantly custom combinations of these functions. Here, the design and performance of the cIM-MS instrument is highlighted, with a mobility resolving power of approximately 750 demonstrated for 100 passes around the cIM device using a reverse sequence peptide pair. The multifunction capabilities are demonstrated through analysis of three isomeric pentasaccharide species and the small protein ubiquitin.Gilleaudeau, G.J., Romaniello, S.J., Luo, G., Kaufman, A.J., Zhang, F., Klaebe, R.M., Kah, L.C., Azmy, K., Bartley, J.K., Zheng, W., Knoll, A.H., Anbar, A.D., 2019. Uranium isotope evidence for limited euxinia in mid-Proterozoic oceans. Earth and Planetary Science Letters 521, 150-157. Earth's oxygenation history is key to deciphering environmental controls on early biospheric evolution. During the mid-Proterozoic Eon, low (but potentially variable) atmospheric pO2 led to highly heterogeneous marine redox conditions, with most studies indicating a relatively shallow depth of oxygen penetration. The relative proportion of oxic, anoxic and iron-rich (ferruginous), and anoxic and sulfide-rich (euxinic) conditions on the global seafloor is difficult to quantify, however, due to a general reliance on local redox proxies applied to the temporally discontinuous black shale record. It is particularly important to constrain the global prevalence of euxinic bottom waters because sulfide toxicity has been implicated as a primary constraint on evolution in mid-Proterozoic oceans and limits the solubility of bioessential trace metals such as copper, zinc, and molybdenum. Here, we present a suite of new uranium (U) isotope data from marine carbonate rocks that span the entire mid-Proterozoic interval (～1.8 to 0.8 Ga). U-isotopes in well-preserved carbonate rocks represent a powerful new proxy that can be used to quantitatively constrain the global extent of marine euxinia. The median δ238U value for mid-Proterozoic carbonate samples is ?0.43‰, which is lower than the median value for modern post-depositional carbonate sediments from the Bahamas, yet significantly higher than carbonate δ238U values recorded during other times of expanded anoxia in Earth history, such as during the end-Permian mass extinction. When paired with a three-sink isotope mass balance model, our data indicate that no more than 7% of the global seafloor was euxinic during the mid-Proterozoic Eon, although transient pulses of expanded euxinia are recorded. Although these results challenge early expectations of a sulfide-rich mid-Proterozoic ocean, they are consistent with more recent inferences from the black shale trace metal record. Evidence therefore indicates that euxinic bottom waters were relatively limited in their spatial extent in the mid-Proterozoic oceans.Gillman, M.P., Erenler, H.E., Sutton, P.J., 2019. Mapping the location of terrestrial impacts and extinctions onto the spiral arm structure of the Milky Way. International Journal of Astrobiology 18, 323-328. regions within the spiral arms are expected to have profound effects on passing stars. Understanding of the potential effects on the Earth and our Solar System is dependent on a robust model of arm passage dynamics. Using a novel combination of data, we derive a model of the timings of the Solar System through the spiral arms and the relationship to arm tracers such as methanol masers. This reveals that asteroid/comet impacts are significantly clustered near the spiral arms and within specific locations of an average arm structure. The end-Permian and end-Cretaceous extinctions emerge as being located within a small star-formation region in two different arms. The start of the Solar System, greater than 4.5 Ga, occurs in the same region in a third arm. The model complements geo-chemical data in determining the relative importance of extra-Solar events in the diversification and extinction of life on Earth.Giorgioni, M., Jovane, L., Rego, E.S., Rodelli, D., Frontalini, F., Coccioni, R., Catanzariti, R., ?zcan, E., 2019. Carbon cycle instability and orbital forcing during the Middle Eocene Climatic Optimum. Scientific Reports 9, 9357. Middle Eocene Climatic Optimum (MECO) is a global warming event that occurred at about 40?Ma. In comparison to the most known global warming events of the Paleogene, the MECO has some peculiar features that make its interpretation controversial. The main peculiarities of the MECO are a duration of ~500 kyr and a carbon isotope signature that varies from site to site. Here we present new carbon and oxygen stable isotopes records (δ13C and δ18O) from three foraminiferal genera dwelling at different depths throughout the water column and the sea bottom during the middle Eocene, from eastern Turkey. We document that the MECO is related to major oceanographic and climatic changes in the Neo-Tethys and also in other oceanic basins. The carbon isotope signature of the MECO is difficult to interpret because it is highly variable from site to site. We hypothesize that such δ13C signature indicates highly unstable oceanographic and carbon cycle conditions, which may have been forced by the coincidence between a 400 kyr and a 2.4?Myr orbital eccentricity minimum. Such forcing has been also suggested for the Cretaceous Oceanic Anoxic Events, which resemble the MECO event more than the Cenozoic hyperthermals.Giorio, C., Moyroud, E., Glover, B.J., Kalberer, M., 2019. Direct depolymerization coupled to liquid extraction surface analysis-high-resolution mass spectrometry for the characterization of the surface of plant tissues. Analytical Chemistry 91, 8326-8333. cuticle, the outermost layer covering the epidermis of most aerial organs of land plants, can have a heterogeneous composition even on the surface of the same organ. The main cuticle component is the polymer cutin which, depending on its chemical composition and structure, can have different biophysical properties. In this study, we introduce a new on-surface depolymerization method coupled to liquid extraction surface analysis (LESA) high-resolution mass spectrometry (HRMS) for a fast and spatially resolved chemical characterization of the cuticle of plant tissues. The method is composed of an on-surface saponification, followed by extraction with LESA using a chloroform–acetonitrile–water (49:49:2) mixture and direct HRMS detection. The method is also compared with LESA-HRMS without prior depolymerization for the analysis of the surface of the petals of Hibiscus richardsonii flowers, which have a ridged cuticle in the proximal region and a smooth cuticle in the distal region. We found that on-surface saponification is effective enough to depolymerize the cutin into its monomeric constituents thus allowing detection of compounds that were not otherwise accessible without a depolymerization step. The effect of the depolymerization procedure was more pronounced for the ridged/proximal cuticle, which is thicker and richer in epicuticular waxes compared with the cuticle in the smooth/distal region of the petal.Girona-García, A., Badía-Villas, D., Jiménez-Morillo, N.T., González-Pérez, J.A., 2019. Changes in soil organic matter composition after Scots pine afforestation in a native European beech forest revealed by analytical pyrolysis (Py-GC/MS). Science of The Total Environment 691, 1155-1161. introduction of coniferous species in former deciduous forests may exert changes in soil organic matter, particularly in its molecular composition. In this work, pyrolysis-gas chromatography–mass spectrometry was used to study changes in SOM quality related to the centennial afforestation of Scots pine in an area formerly covered by European beech forest in the NE-flank of the Moncayo Natural Park (NE-Spain). For each soil profile three organic layers (fresh litter, fragmented litter and humified litter) and mineral soil horizons (Ah, E, Bhs and C) were studied. A total of 128 compounds were identified in the pyrograms, and composition differences were detected among the organic and mineral soil layers as well as between soils under beech and pine, for the main compound classes: nitrogen compounds, aromatics, lignin methoxyphenols, polycyclic aromatic hydrocarbons, lipids and polysaccharide-derived moieties. Such chemical differences were found to be derived from the biomass composition of the predominant vegetation type that was incorporated into the soil and from its progression into the soil profile. The analysis of the distribution of alkanes indicated higher SOM stabilization in the native beech forest soil. The signal of beech biomarkers (long chain n-alkanes C31-C33) found in the pine E horizon indicates the permanence of SOM derived from the natural forest ca. 100?years after the afforestation.Glock, N., Liebetrau, V., Vogts, A., Eisenhauer, A., 2019. Organic heterogeneities in foraminiferal calcite traced through the distribution of N, S, and I measured with NanoSIMS: A new challenge for element-ratio-based paleoproxies? Frontiers in Earth Science 7, 175. doi: 10.3389/feart.2019.00175. oxygen decline due to anthropogenic climate change is a matter of growing concern. A quantitative oxygen proxy is highly desirable in order to identify and monitor recent dynamics as well as to reconstruct pre-Anthropocene changes in amplitude and extension of oxygen depletion. Geochemical proxies like foraminiferal I/Ca ratios seem to be promising redox proxies. Nevertheless, recent studies on microanalyses of benthic foraminiferal I/Ca ratios at the Peruvian Oxygen Minimum Zone (OMZ) measured with Secondary-Ion-Mass-Spectrometry (SIMS) revealed a possible association of iodine with organic accumulations within the test. Here we present a new study on the micro-distribution of nitrogen, sulphur and iodine within the test-walls of Uvigerina striata from the Peruvian OMZ measured with Nano-SIMS. A quantification of the foraminiferal I/Ca ratios from our NanoSIMS study is in good agreement with quantitative results from a previous SIMS study. Additionally, we compared uncleaned specimens with specimens that have been treated with an oxidative cleaning procedure. Both nitrogen and sulfur, which are used as tracer for organic matter, show a patchy distribution within the test walls of the uncleaned specimens and a statistically significant correlation with the iodine distribution. This patchy organic rich phase has a different geochemical signature than the pristine calcitic parts of the test and another phase that shows a banding like structure and that is characterized by a strong sulfur enrichment. All three elements, sulfur, nitrogen and iodine, are strongly depleted in the cleaned specimens, even within the massive parts of the test walls that lack the connection with the test pores. These results indicate that the organic parts of the test walls are located inside a microporous framework within the foraminiferal calcite. This has to be considered in the interpretation of geochemical proxies on foraminiferal calcite, especially for microanalytical methods, since the chemical signature of these organic parts likely alters some element to Calcium ratios within the foraminiferal test.Goetghebuer, L., Bonal, M., Faust, K., Servais, P., George, I.F., 2019. The dynamic of a river model bacterial community in two different media reveals a divergent succession and an enhanced growth of most strains compared to monocultures. Microbial Ecology 78, 313-323. dynamic of a community of 20 bacterial strains isolated from river water was followed in R2 broth and in autoclaved river water medium for 27?days in batch experiments. At an early stage of incubation, a fast-growing specialist strain, Acinetobater sp., dominated the community in both media. Later on, the community composition in both media diverged but was highly reproducible across replicates. In R2, several strains previously reported to degrade multiple simple carbon sources prevailed. In autoclaved river water, the community was more even and became dominated by several strains growing faster or exclusively in that medium. Those strains have been reported in the literature to degrade complex compounds. Their growth rate in the community was 1.5- to 7-fold greater than that observed in monoculture. Furthermore, those strains developed simultaneously in the community. Together, our results suggest the existence of cooperative interactions within the community incubated in autoclaved river water.Golubic, S., Schneider, J., Le Campion-Alsumard, T., Campbell, S.E., Hook, J.E., Radtke, G., 2019. Approaching microbial bioerosion. Facies 65, 25. participation of microorganisms in construction and destruction of sedimentary structures is widely recognized, and so is the importance of studying such geological processes in modern systems, where the conditions, participating forces, and the results can be observed and recorded. This information is important for understanding and interpreting corresponding processes if their effects were preserved as part of the fossil record. The present contribution refers to topics discussed during the 9th International Bioerosion Workshop in Rome on Oct. 23–27, 2017, dedicated to the evaluation of microbial traces as paleoecological and paleobathymetric indicators. The paper reviews the habitats, methods of collection, and preparation of samples, followed by observation of extracted microbial euendoliths. This approach is complemented by producing images of three-dimensional display of inhabited microborings in their original positions using resin-casting and double embedding of the microbially invaded substrates. This contribution stresses the value of recognizing the microboring organisms’ identities as a key aspect of the interpretation of their traces. It discusses different and complementary ways of how to achieve such parallel assessments. It reports on the importance of photo-documentation and morphometric evaluation of microbial populations, while avoiding possible artefacts caused by the methods used. The study also briefly summarizes the distribution patterns of microboring organisms and their boring and etching traces along depth profiles. Problems arising in the naming of complex traces and the relation to biological nomenclature are discussed.Gómez-Peral, L.E., Arrouy, M.J., Poiré, D.G., Cavarozzi, C.E., 2019. Redox-sensitive trace element distribution in the Loma Negra Formation in Argentina: The record of an Ediacaran oxygenation event. Precambrian Research 332, 105384. limestones of the Loma Negra Formation provide an excellent opportunity to examine the behaviour of rare earth elements plus yttrium (REY) due to the near-zero diagenetic alteration of the carbonate system. The terrigenous supply to this unit was minimal or scarce in relation to the depth of seawater in which the limestones accumulated. The interpreted palaeoenvironment suggests that limestones could have originated by suspension fall-out in a shallow, open marine ramp. The diagenetic features, composition, and original microtextures are considered good criteria for investigating their REY composition. Burial diagenesis products were limited and limestones largely preserved their original texture and organic matter, as well as their isotope and trace element composition. The study of REY distribution in the Loma Negra Formation in different settings of the Tandilia System revealed systematic chemostratigraphic patterns related to uniform palaeo-redox conditions. The general light rare-earth element depletion, marked positive La, Y, and Gd anomalies, as well as the clear negative Ce anomalies, are further features typically ascribed to oxidizing seawater conditions. From these results, it can be concluded that the Loma Negra Formation documents an oxygenation event that stands out in the overall anoxic Ediacaran ocean. This record may be correlated with the mid-Ediacaran oxygenation event (ca. 580?Ma). This may support the hypothesis that the Clymene Ocean was well oxygenated and connected during the Ediacaran, at least in the southwestern border of Gondwana.Gong, B., Cao, H., Peng, C., Per?ulija, V., Tong, G., Fang, H., Wei, X., Ouyang, S., 2019. High-throughput sequencing and analysis of microbial communities in the mangrove swamps along the coast of Beibu Gulf in Guangxi, China. Scientific Reports 9, 9377. swamp is one of the world’s richest and most productive marine ecosystems. This ecosystem also has a great ecological importance, but is highly susceptible to anthropogenic disturbances. The balance of mangrove ecosystem depends largely on the microbial communities in mangrove sediments. Thus, understanding how the mangrove microbial communities respond to spatial differences is essential for more accurate assessment of mangrove ecosystem health. To this end, we performed the first medium-distance (150?km) research on the biogeographic distribution of mangrove microbial communities. The hypervariable regions of 16S rRNA gene was sequenced by Illumina to compare the microbial communities in mangrove sediments collected from six locations (i.e. Zhenzhu harbor, Yuzhouping, Maowei Sea, Qinzhou harbor, Beihai city and Shankou) along the coastline of Beibu Gulf in Guangxi province, China. Collectively, Proteobacteria, Bacteroidetes, Chloroflexi, Actinobacteria, Parvarchaeota, Acidobacteria and Cyanobacteria were the predominant phyla in the mangrove sediments of this area. At genus level, the heat map of microbial communities reflected similarities between study sites and was in agreement with their biogeographic characteristics. Interestingly, the genera Desulfococcus, Arcobacter, Nitrosopumilus and Sulfurimonas showed differences in abundance between study sites. Furthermore, the principal component analysis (PCA) and unweighted UniFrac cluster tree of beta diversity were used to study the biogeographic diversity of the microbial communities. Relatively broader variation of microbial communities was found in Beihai city and Qinzhou harbour, suggesting that environmental condition and historical events may play an important role in shaping the bacterial communities as well. This is the first report on medium-distance range distribution of bacteria in the mangrove swamp ecosystem. Our data is valuable for monitoring and evaluation of the impact of human activity on mangrove habitats from the perspective of microbiome.Gonzalez, E., Pitre, F.E., Brereton, N.J.B., 2019. ANCHOR: a 16S rRNA gene amplicon pipeline for microbial analysis of multiple environmental samples. Environmental Microbiology 21, 2440-2468. of 16S ribosomal RNA (rRNA) gene amplification data for microbial barcoding can be inaccurate across complex environmental samples. A method, ANCHOR, is presented and designed for improved species-level microbial identification using paired-end sequences directly, multiple high-complexity samples and multiple reference databases. A standard operating procedure (SOP) is reported alongside benchmarking against artificial, single sample and replicated mock data sets. The method is then directly tested using a real-world data set from surface swabs of the International Space Station (ISS). Simple mock community analysis identified 100% of the expected species and 99% of expected gene copy variants (100% identical). A replicated mock community revealed similar or better numbers of expected species than MetaAmp, DADA2, Mothur and QIIME1. Analysis of the ISS microbiome identified 714 putative unique species/strains and differential abundance analysis distinguished significant differences between the Destiny module (U.S. laboratory) and Harmony module (sleeping quarters). Harmony was remarkably dominated by human gastrointestinal tract bacteria, similar to enclosed environments on earth; however, Destiny module bacteria also derived from nonhuman microbiome carriers present on the ISS, the laboratory's research animals. ANCHOR can help substantially improve sequence resolution of 16S rRNA gene amplification data within biologically replicated environmental experiments and integrated multidatabase annotation enhances interpretation of complex, nonreference microbiomes.Greene, S.E., Ridgwell, A., Kirtland Turner, S., Schmidt, D.N., P?like, H., Thomas, E., Greene, L.K., Hoogakker, B.A.A., 2019. Early Cenozoic decoupling of climate and carbonate compensation depth trends. Paleoceanography and Paleoclimatology 34, 930-945.: Our understanding of the long‐term evolution of the Earth system is based on the assumption that terrestrial weathering rates should respond to, and hence help regulate, atmospheric CO2 and climate. Increased terrestrial weathering requires increased carbonate accumulation in marine sediments, which in turn is expected to result in a long‐term deepening of the carbonate compensation depth (CCD). Here, we critically assess this long‐term relationship between climate and carbon cycling. We generate a record of marine deep‐sea carbonate abundance from selected late Paleocene through early Eocene time slices to reconstruct the position of the CCD. Although our data set allows for a modest CCD deepening, we find no statistically significant change in the CCD despite >3 °C global warming, highlighting the need for additional deep‐sea constraints on carbonate accumulation. Using an Earth system model, we show that the impact of warming and increased weathering on the CCD can be obscured by the opposing influences of ocean circulation patterns and sedimentary respiration of organic matter. From our data synthesis and modeling, we suggest that observations of warming, declining δ13C and a relatively stable CCD can be broadly reproduced by mid‐Paleogene increases in volcanic CO2 outgassing and weathering. However, remaining data‐model discrepancies hint at missing processes in our model, most likely involving the preservation and burial of organic carbon. Our finding of a decoupling between the CCD and global marine carbonate burial rates means that considerable care is needed in attempting to use the CCD to directly gauge global carbonate burial rates and hence weathering rates.Plain Language Summary: Weathering, the breakdown of rocks at the Earth's surface, is widely assumed to act as Earth's thermostat, regulating the concentration of atmospheric carbon dioxide (CO2) and global temperatures. This is because (a) weathering consumes CO2 from the atmosphere and (b) weathering rates are thought to be greater at higher temperatures. One widely used proxy for reconstructing global weathering is the preservation of calcium carbonate (chalk) minerals in the deep ocean. From the late Paleocene to early Eocene, the planet warmed by more 3 °C, the biggest long‐term global warming trend for which we have detailed records. It is still uncertain whether global weathering responded to this temperature increase. We reconstruct the preservation of deep‐sea calcium carbonate across this warming and find little apparent change. We also use computer modeling to show that the relationship between global weathering and preservation of deep‐sea calcium carbonate is highly nuanced. In sum, we are able to attribute the late Paleocene to early Eocene warming to an increase in CO2 emissions from volcanoes. We argue the resulting elevated temperatures did, in fact, cause an increase in global weathering, but that this is not readily apparent from our deep‐sea calcium carbonate proxy.Greenlon, A., Chang, P.L., Damtew, Z.M., Muleta, A., Carrasquilla-Garcia, N., Kim, D., Nguyen, H.P., Suryawanshi, V., Krieg, C.P., Yadav, S.K., Patel, J.S., Mukherjee, A., Udupa, S., Benjelloun, I., Thami-Alami, I., Yasin, M., Patil, B., Singh, S., Sarma, B.K., von Wettberg, E.J.B., Kahraman, A., Bukun, B., Assefa, F., Tesfaye, K., Fikre, A., Cook, D.R., 2019. Global-level population genomics reveals differential effects of geography and phylogeny on horizontal gene transfer in soil bacteria. Proceedings of the National Academy of Sciences 116, 15200-15209.: Legume crops are significant agriculturally and environmentally for their ability to form a symbiosis with specific soil bacteria capable of nitrogen fixation. However, nitrogen fixation is limited by the availability of the legume host’s bacterial partners in a given soil, and by strain variance in symbiotic effectiveness. In intensively managed agriculture systems, legume crops are provided specific inoculants; inoculation can fail if the added strains are unable to compete in soil with less symbiotically efficient endemic strains. Biogeographic insight is vital to understand what factors affect nitrogen fixation in legume crops and techniques to improve nitrogen fixation. Similarly, understanding the relationship between a legume crop’s symbionts in a geographic context can elucidate broader principles of microbial biogeography.Abstract: Although microorganisms are known to dominate Earth’s biospheres and drive biogeochemical cycling, little is known about the geographic distributions of microbial populations or the environmental factors that pattern those distributions. We used a global-level hierarchical sampling scheme to comprehensively characterize the evolutionary relationships and distributional limitations of the nitrogen-fixing bacterial symbionts of the crop chickpea, generating 1,027 draft whole-genome sequences at the level of bacterial populations, including 14 high-quality PacBio genomes from a phylogenetically representative subset. We find that diverse Mesorhizobium taxa perform symbiosis with chickpea and have largely overlapping global distributions. However, sampled locations cluster based on the phylogenetic diversity of Mesorhizobium populations, and diversity clusters correspond to edaphic and environmental factors, primarily soil type and latitude. Despite long-standing evolutionary divergence and geographic isolation, the diverse taxa observed to nodulate chickpea share a set of integrative conjugative elements (ICEs) that encode the major functions of the symbiosis. This symbiosis ICE takes 2 forms in the bacterial chromosome—tripartite and monopartite—with tripartite ICEs confined to a broadly distributed superspecies clade. The pairwise evolutionary relatedness of these elements is controlled as much by geographic distance as by the evolutionary relatedness of the background genome. In contrast, diversity in the broader gene content of Mesorhizobium genomes follows a tight linear relationship with core genome phylogenetic distance, with little detectable effect of geography. These results illustrate how geography and demography can operate differentially on the evolution of bacterial genomes and offer useful insights for the development of improved technologies for sustainable agriculture.Gregson, B.H., Metodieva, G., Metodiev, M.V., McKew, B.A., 2019. Differential protein expression during growth on linear versus branched alkanes in the obligate marine hydrocarbon-degrading bacterium Alcanivorax borkumensis SK2T. Environmental Microbiology 21, 2347-2359. borkumensis SK2T is an important obligate hydrocarbonoclastic bacterium (OHCB) that can dominate microbial communities following marine oil spills. It possesses the ability to degrade branched alkanes which provides it a competitive advantage over many other marine alkane degraders that can only degrade linear alkanes. We used LC–MS/MS shotgun proteomics to identify proteins involved in aerobic alkane degradation during growth on linear (n‐C14) or branched (pristane) alkanes. During growth on n‐C14, A. borkumensis expressed a complete pathway for the terminal oxidation of n‐alkanes to their corresponding acyl‐CoA derivatives including AlkB and AlmA, two CYP153 cytochrome P450s, an alcohol dehydrogenase and an aldehyde dehydrogenase. In contrast, during growth on pristane, an alternative alkane degradation pathway was expressed including a different cytochrome P450, an alcohol oxidase and an alcohol dehydrogenase. A. borkumensis also expressed a different set of enzymes for β‐oxidation of the resultant fatty acids depending on the growth substrate utilized. This study significantly enhances our understanding of the fundamental physiology of A. borkumensis SK2T by identifying the key enzymes expressed and involved in terminal oxidation of both linear and branched alkanes. It has also highlights the differential expression of sets of β‐oxidation proteins to overcome steric hinderance from branched substrates.Guo, H., Zhang, Y., Zhang, J., Huang, Z., Urynowicz, M.A., Liang, W., Han, Z., Liu, J., 2019. Characterization of anthracite-degrading methanogenic microflora enriched from Qinshui Basin in China. Energy & Fuels 33, 6380-6389. are essential for the formation of biogenic coalbed methane (CBM) and the application of microbially enhanced CBM (MECoM). Anthracite-degrading methanogenic microflora was cultivated by enrichment and subculture from produced water obtained in Qinshui Basin where CBM is explored commercially. The maximum methane yield was 255 μmol/g of coal after 23 days of cultivation at 35 °C, 1.1–1.2% of salinity, <0.15 mm of coal particle size, pH 8–9, and 5 mL of inocula/g of coal. Microflora archaea, as revealed by MiSeq, were mainly composed of Methanosaeta, an acetic acid-consuming methanogen, followed by Methanocella, a hydrogen-consuming methanogen, suggesting a diversity of methanogenic pathways with a dominance of acetoclastic methanogenesis. The bacteria mainly included Enterobacter, Acetoanaerobium, Macellibacteroides, Clostridium, and Ercella. FTIR analysis showed that the oxygen-containing groups and aliphatic groups were the main targets for microbial degradation. XRD analysis indicated that crystal nucleus structures of coal decreased after degradation. The concentrations of aliphatics were shown to increase over the incubation period based on GC–MS analysis, while the concentrations of dissolved aromatics decreased. These results show the potential for enhancing CBM production by stimulating the activity of methanogenic consortia in situ in Qinshui Basin as well as other high-rank coal reservoirs.Gushchin, P.A., Cheremisin, A.N., Zobov, P.M., Shcherbakova, A.V., Khlebnikov, V.N., 2019. Use of dispersed solid matter of Bazhenov Formation for developing light oil reserves. Chemistry and Technology of Fuels and Oils 55, 165-173. the conditions of the low-permeable Tyumen Formation, associated petroleum gas (APG) and intrastratal air transformation product are similar in oil-displacing properties. A new approach to the development of oil reserves of the Tyumen and Bazhenov Formations is proposed. It lies in the fact that, when solid organic matter of the Bazhenov Formation dispersed in the rock mass is oxidized, air; rather than oil, should be transformed into an inert gaseous agent. At the same time, artificial fractures will be formed if the rock of the Bazhenov Formation is heated unevenly. Translated from Khimiya i Tekhnologiya Topliv i Mosel, No. 2, pp. 30 — 35, March —April, 2019.Guzman, M., Lorenz, R., Hurley, D., Farrell, W., Spencer, J., Hansen, C., Hurford, T., Ibea, J., Carlson, P., McKay, C.P., 2019. Collecting amino acids in the Enceladus plume. International Journal of Astrobiology 18, 47-59. numerically model the dynamics of the Enceladus plume ice grains and define our nominal plume model as having a particle size distribution n(R) ~ R?q with q = 4 and a total particulate mass rate of 16 kg s?1. This mass rate is based on average plume brightness observed by Cassini across a range of orbital positions. The model predicts sample volumes of ~1600 ?g for a 1 m2 collector on a spacecraft making flybys at 20–60 km altitudes above the Enceladus surface. We develop two scenarios to predict the concentration of amino acids in the plume based on these assumed sample volumes. We specifically consider Glycine, Serine, α-Alanine, α-Aminoisobutyric acid and Isovaline. The first ‘abiotic’ model assumes that Enceladus has the composition of a comet and finds abundances between 2 × 10?6 to 0.003 ?g for dissolved free amino acids and 2 × 10?5 to 0.3 ?g for particulate amino acids. The second ‘biotic’ model assumes that the water of Enceladus's ocean has the same amino acid composition as the deep ocean water on Earth. We compute the expected captured mass of amino acids such as Glycine, Serine, and α-Alanine in the ‘biotic’ model to be between 1 × 10?5 to 2 × 10?5 ?g for dissolved free amino acids and dissolved combined amino acids and about 0.0002 ?g for particulate amino acids. Both models consider enhancements due to bubble bursting. Expected captured mass of amino acids is calculated for a 1 m2 collector on a spacecraft making flybys with a closest approach of 20 km during mean plume activity for the given nominal particle size distribution.Hahn, A., Gerdts, G., V?lker, C., Niebühr, V., 2019. Using FTIRS as pre-screening method for detection of microplastic in bulk sediment samples. Science of The Total Environment 689, 341-346. present calibration models for the detection of two types of plastic (LDPE, PET) in sediments, developed from analysis of synthetic sediment mixtures and application of Fourier transform infrared spectroscopy (FTIRS) and partial least squares regression (PLSR) modeling. Synthetic sediment mixtures were produced using ground plastic particles mixed with various different sediment matrixes yielding LDPE and PET contents ranging from 0 to 5?wt%. The resulting PLSR calibration models between the FTIRS spectral information and the defined plastic concentration of the synthetic sediment mixtures show strong cross-validated correlations (R2CV?=?0.73 and 0.72) as well as low root-mean square errors of cross-validation (RMSECV?=?0.72 and 0.61; 14.4% and 12.2% when expressed as % of gradient). Application of the calibration to natural sediments shows that the method can be used to detect the presence of microplastics in sediment. The results are only semi-quantitative and semi-qualitative, and the method is suitable mainly for samples with very high microplastic concentrations (>1%). However the major advantage of this procedure is the time and cost efficiency. For studies with large amounts of samples (e.g. monitoring applications) we recommend this method as a pre-screening tool for selecting samples with plastic content for further analysis.Hakim, K., Spaargaren, R., Grewal, D.S., Rohrbach, A., Berndt, J., Dominik, C., van Westrenen, W., 2019. Mineralogy, structure, and habitability of carbon-enriched rocky exoplanets: A laboratory approach. Astrobiology 19, 867-884. rocky exoplanets have been proposed to occur around dwarf stars as well as binary stars, white dwarfs, and pulsars. However, the mineralogical make up of such planets is poorly constrained. We performed high-pressure high-temperature laboratory experiments (P?=?1–2 GPa, T?=?1523–1823 K) on chemical mixtures representative of C-enriched rocky exoplanets based on calculations of protoplanetary disk compositions. These P-T conditions correspond to the deep interiors of Pluto- to Mars-sized planets and the upper mantles of larger planets. Our results show that these exoplanets, when fully differentiated, comprise a metallic core, a silicate mantle, and a graphite layer on top of the silicate mantle. Graphite is the dominant carbon-bearing phase at the conditions of our experiments with no traces of silicon carbide or carbonates. The silicate mineralogy comprises olivine, orthopyroxene, clinopyroxene, and spinel, which is similar to the mineralogy of the mantles of carbon-poor planets such as the Earth and largely unaffected by the amount of carbon. Metals are either two immiscible iron-rich alloys (S-rich and S-poor) or a single iron-rich alloy in the Fe-C-S system with immiscibility depending on the S/Fe ratio and core pressure. We show that, for our C-enriched compositions, the minimum carbon abundance needed for C-saturation is 0.05–0.7?wt% (molar C/O ～0.002–0.03). Fully differentiated rocky exoplanets with C/O ratios more than that needed for C-saturation would contain graphite as an additional layer on top of the silicate mantle. For a thick enough graphite layer, diamonds would form at the bottom of this layer due to high pressures. We model the interior structure of Kepler-37b and show that a mere 10?wt% graphite layer would decrease its derived mass by 7%, which suggests that future space missions that determine both radius and mass of rocky exoplanets with insignificant gaseous envelopes could provide quantitative limits on their carbon content. Future observations of rocky exoplanets with graphite-rich surfaces would show low albedos due to the low reflectance of graphite. The absence of life-bearing elements other than carbon on the surface likely makes them uninhabitable.Hamm, J.N., Erdmann, S., Eloe-Fadrosh, E.A., Angeloni, A., Zhong, L., Brownlee, C., Williams, T.J., Barton, K., Carswell, S., Smith, M.A., Brazendale, S., Hancock, A.M., Allen, M.A., Raftery, M.J., Cavicchioli, R., 2019. Unexpected host dependency of Antarctic Nanohaloarchaeota. Proceedings of the National Academy of Sciences 116, 14661-14670.: We demonstrate that Candidatus Nanohaloarchaeum antarcticus requires Halorubrum lacusprofundi for growth, illustrating that Nanohaloarchaeota require a host rather than being free living as previously proposed. Developing the means of cultivating Nanohaloarchaeota in the laboratory provides the capacity to advance understanding of how archaea interact and the factors that control their symbiotic relationship (e.g. mutualism, commensalism, antagonism). Our findings amplify the view that Antarctic lakes are a treasure trove for the discovery of microbes with previously unknown properties.Abstract: In hypersaline environments, Nanohaloarchaeota (Diapherotrites, Parvarchaeota, Aenigmarchaeota, Nanoarchaeota, Nanohaloarchaeota [DPANN] superphylum) are thought to be free-living microorganisms. We report cultivation of 2 strains of Antarctic Nanohaloarchaeota and show that they require the haloarchaeon Halorubrum lacusprofundi for growth. By performing growth using enrichments and fluorescence-activated cell sorting, we demonstrated successful cultivation of Candidatus Nanohaloarchaeum antarcticus, purification of Ca. Nha. antarcticus away from other species, and growth and verification of Ca. Nha. antarcticus with Hrr. lacusprofundi; these findings are analogous to those required for fulfilling Koch’s postulates. We use fluorescent in situ hybridization and transmission electron microscopy to assess cell structures and interactions; metagenomics to characterize enrichment taxa, generate metagenome assembled genomes, and interrogate Antarctic communities; and proteomics to assess metabolic pathways and speculate about the roles of certain proteins. Metagenome analysis indicates the presence of a single species, which is endemic to Antarctic hypersaline systems that support the growth of haloarchaea. The presence of unusually large proteins predicted to function in attachment and invasion of hosts plus the absence of key biosynthetic pathways (e.g., lipids) in metagenome assembled genomes of globally distributed Nanohaloarchaeota indicate that all members of the lineage have evolved as symbionts. Our work expands the range of archaeal symbiotic lifestyles and provides a genetically tractable model system for advancing understanding of the factors controlling microbial symbiotic relationships.Hammer, P.G., Yi, R., Yoda, I., Cleaves, H.J., Callahan, M.P., 2019. Radiolysis of solid-state nitrogen heterocycles provides clues to their abundance in the early solar system. International Journal of Astrobiology 18, 289-295. studied the radiolysis of a wide variety of N-heterocycles, including many of biological importance, and find that the majority are remarkably stable in the solid-state when subjected to large doses of ionizing gamma radiation from a 60Co source. Degradation of N-heterocycles as a function of dose rate and total dose was measured using high-performance liquid chromatography with UV detection. Many N-heterocycles show little degradation when γ-irradiated up to a total dose of ~1 MGy, which approximates hundreds of millions of years’ worth of radiation emitted in meteorite parent bodies due to slow radionuclide decay. Extrapolation of these results suggests that these N-heterocyclic compounds would be stable in dry parent bodies over solar system timescales. We suggest that the abundance of these N-heterocycles as measured presently in carbonaceous meteorites is largely reflective of their abundance at the time aqueous alteration stopped in their parent bodies and the absence of certain compounds in present-day samples is either due to the formation mechanisms or degradation which occurred during periods of aqueous alteration or thermal metamorphism.Hammerli, J., Kemp, A.I.S., Whitehouse, M.J., 2019. In situ trace element and Sm-Nd isotope analysis of accessory minerals in an Eoarchean tonalitic gneiss from Greenland: Implications for Hf and Nd isotope decoupling in Earth's ancient rocks. Chemical Geology 524, 394-405. of the Earth's oldest preserved continental crustal rocks, from southern West Greenland, contain contradictory radiogenic isotope signatures, whereby Hf isotope ratios are chondritic but Nd isotope ratios are distinctly super-chondritic. Models to explain this discrepancy are speculative and variously invoke deep magma ocean crystallisation, HfNd decoupling in subduction zones, or metamorphic disturbance during younger thermal events. Determining the cause of this discrepancy is essential for understanding Eoarchean crust-mantle differentiation. We employ, for the first time, micro-analysis of REE-rich accessory minerals to shed light on the Nd isotope evolution of a key tonalitic gneiss sample from southern West Greenland that displays the apparent HfNd isotope decoupling. The results show that the Sm-Nd isotope system was homogenized during a metamorphic event at ca. 2690?Ma. We suggest that metamorphic reactions involving consumption and re-crystallisation of REE-bearing phases were accompanied by LREE element mobility and the loss of unradiogenic Nd, shifting the bulk rock composition to a more radiogenic Nd isotope value. Our study provides the first direct evidence that the anomalous Nd isotope signatures in some Eoarchean gneisses are artefacts of the disturbance of the Sm-Nd isotope system, and not due to extensive differentiation of the bulk silicate Earth by magma ocean crystallisation or continental crust formation.Han, M., Kong, J., Yuan, J., He, H., Hu, J., Yang, S., Li, S., Zhang, L., Sun, C., 2019. Method development for simultaneous analyses of polycyclic aromatic hydrocarbons and their nitro-, oxy-, hydroxy- derivatives in sediments. Talanta 205, 120128. is important to establish an available analytical method for polycyclic aromatic hydrocarbons (PAHs), nitrated PAHs (nitro-PAHs), oxygenated forms of PAHs (oxy-PAHs), and hydroxy-PAHs (OH-PAHs) in sediment samples due to the fact that they co-exist in various environmental mediates, particularly in sediment. In this study, an analytical method has been developed and validated for the quantification of PAHs, nitro-PAHs, oxy-PAHs, and OH-PAHs in sediment samples. The sediment samples were extracted by accelerated solvent extraction and cleaned up with SPE alumina-n combining with aminopropyl cartridges. The extracts were further fractionated by using different solvents. The fractionated extracts were analyzed via gas chromatography of single and triple quadrupole mass spectrometry in the electron ionization and negative ion chemical ionization with selective ion monitoring and selective reaction monitoring mode and liquid chromatography-triple quadrupole mass spectrometry. Each group of analytes was determined by different instrument modes such as GC-EI-SIM for PAHs, GC-NICI-SRM for nitro-PAHs, GC-EI-SRM for the oxy-PAHs and LC-ESI-MS/MS for OH-PAHs. A total of 44 analytes (16?PAHs, 14 nitro-PAHs, 9 oxy-PAHs, and 5 OH-PAHs) and 6 deuterated surrogates were performed. Most of recovery percentage varied from 52.8% up to 114.1% for the targeted analytes verified at three concentration levels (100?ng/g, 400?ng/g and 1000?ng/g for PAHs and 10?ng/g, 50?ng/g and 400?ng/g for their derivatives). The repeatability determined by the relative standard deviation percentage of triplicate trials was less than 10% for most analytes. The limit of detection ranged from 0.01 to 0.02?ng/g for PAHs, 0.002–0.067?ng/g for nitro-PAHs, 0.01–0.1?ng/g for oxy-PAHs, and 0.003–0.006?ng/g for OH-PAHs. Most of the compounds were detectable in the sediments collected from a local River, which illustrates the developed method could be a practical and suitable technique for detection of PAHs and their derivatives in real sediment samples.Hanke, U.M., Lima-Braun, A.L., Eglinton, T.I., Donnelly, J.P., Galy, V., Poussart, P., Hughen, K., McNichol, A.P., Xu, L., Reddy, C.M., 2019. Significance of perylene for source allocation of terrigenous organic matter in aquatic sediments. Environmental Science & Technology 53, 8244-8251. is a frequently abundant, and sometimes the only polycyclic aromatic hydrocarbon (PAH) in aquatic sediments, but its origin has been subject of a longstanding debate in geochemical research and pollutant forensics because its historical record differs markedly from typical anthropogenic PAHs. Here we investigate whether perylene serves as a source-specific molecular marker of fungal activity in forest soils. We use a well-characterized sedimentary record (1735–1999) from the anoxic-bottom waters of the Pettaquamscutt River basin, RI to examine mass accumulation rates and isotope records of perylene, and compare them with total organic carbon and the anthropogenic PAH fluoranthene. We support our arguments with radiocarbon (14C) data of higher plant leaf-wax n-alkanoic acids. Isotope-mass balance-calculations of perylene and n-alkanoic acids indicate that ～40% of sedimentary organic matter is of terrestrial origin. Further, both terrestrial markers are pre-aged on millennial time-scales prior to burial in sediments and?are?insensitive to elevated 14C concentrations following nuclear weapons testing in the mid-20th Century. Instead, changes coincide with enhanced erosional flux during urban sprawl. These findings suggest that perylene is definitely a product of soil-derived fungi, and a powerful chemical tracer to study the?spatial and temporal connectivity between terrestrial and aquatic environments.Hao, Y., Smith, M.M., Carroll, S.A., 2019. Multiscale modeling of CO2-induced carbonate dissolution: From core to meter scale. International Journal of Greenhouse Gas Control 88, 272-289. transport models can be used to predict the long-term storage capacity of CO2 in carbonate formations if the parameters that couple physical and chemical interactions can be calibrated from centimeters (laboratory-scale) to kilometers (field-scale). However, calibration across length scales is challenging in highly reactive and heterogeneous carbonate reservoirs. In this study we translated simulations of CO2-induced carbonate dissolution and transport processes of centimeter-sized cores to meter-sized rock blocks. The meter-sized rocks represent an intermediate scale between laboratory experiments and field demonstrations.We conducted brute-force, meter-sized simulations maintaining the same grid resolution used to successfully model rock heterogeneities and physical behaviors observed in laboratory experiments. To do this, we applied multi-point statistics to generate rock heterogeneity that honors characterization data, and adopted the reaction and transport parameters (e.g., reaction rate kinetics, porosity-permeability relationship) from models calibrated by core-flood experiments.We used the high-resolution simulation data sets to understand the interplay between carbonate reactivity, flow velocity, and rock heterogeneity on the development and consequences of dissolution fronts at a meter scale, and in particular how parameters that couple chemistry and transport change at variable length scales. The modeling results reveal scale dependence of porosity-permeability relationship and carbonate reactivity. We found that upscaling reactive transport processes from centimeters to meters requires: (1) Effective representation of initial rock heterogeneity and related preferential flow field. In more permeable rocks, several dissolution fingers or wormholes form and grow along the flow direction, competing for reactive solution and leading to fast breakthrough. In less permeable rocks, a single dissolution channel forms with a dramatic increase in lateral branching due to the resistance from low-permeability regions along the flow path. (2) Higher exponential values for porosity-permeability power-law correlations. The value of the power parameter n increases by about two times as we scale the dissolution process from centimeters to meters. (3) Lower carbonate reaction rates. Carbonate reaction rates obtained for meter-sized models are about ten times slower than those for the smaller core-flood experiments. We also used the high-resolution meter-sized simulations to upscale carbonate dissolution by coarsening the representative elementary volumes (or grids). The calibrated reactive transport parameters are consistent with those derived from scaling analysis.The upscaling analysis developed in this study improves our understanding of carbonate dissolution (especially wormhole development) and associated reactive transport across time and length scales, providing a useful basis for establishing a direct relationship between core-scale and field-scale models. Additional work is needed to see if relationships developed from single-phase reactive transport processes shown in this work are directly applicable to in-situ reservoir multiphase flow conditions arising from geological storage of CO2.Harada, M., Nagano, A., Yagi, S., Furukawa, R., Yokobori, S.-i., Yamagishi, A., 2019. Planktonic adaptive evolution to the sea surface temperature in the Neoproterozoic inferred from ancestral NDK of marine cyanobacteria. Earth and Planetary Science Letters 522, 98-106. optimum growth temperature of ancestral cyanobacteria inhabiting the sea surface in the Neoproterozoic was estimated based on the thermal stability of experimentally reconstructed ancestral NDK enzymes. Ancestral NDKs of cyanobacteria that diversified ～1.7, ～1.0, ～0.9, ～0.7, ～0.6, and ～0.5 billion years ago were reconstructed and analyzed, and the unfolding midpoint temperatures (Tms) ranged from ～65°C to ～70°C. Among the host of analyzed NDKs, the ancestors of marine, planktonic α-cyanobacteria diversified ≤ ～1.0 Ga are highly likely to have inhabited marine environments during the Neoproterozoic, while ancestral cyanobacteria diversified ～1.7 billion years ago were possibly marine but the habitat is less constrained compared to the others. According to the calibration curves derived from extant organisms, the obtained Tms of α-cyanobacteria diversified ≤ ～1.0 Ga correspond to the range of optimum growth temperatures of around ～33–48°C. The temperature range agrees well with the long-term sea temperature trend during Neoproterozoic suggested by δ18O and δ30Si records from marine cherts. Adaptation to the low temperature during the snowball glaciations in the late Neoproterozoic was not observed, implying that adaptation of optimum growth conditions to the episodic low temperature may not have been necessary. Therefore, ancestral marine plankton must have consistently adapted to the interglacial sea surface temperature in the Neoproterozoic, which was approximately 5–20°C higher than that is today. They may have survived the glaciations by acquiring cold tolerance and/or by suppressing growth rate.Harning, D.J., Andrews, J.T., Belt, S.T., Cabedo-Sanz, P., Geirsdóttir, ?., Dildar, N., Miller, G.H., Sepúlveda, J., 2019. Sea ice control on winter subsurface temperatures of the North Iceland Shelf during the Little Ice Age: A TEX86 calibration case study. Paleoceanography and Paleoclimatology 34, 1006-1021. paleoceanographic reconstructions along the North Iceland Shelf have employed a variety of sea surface temperature and sea ice proxies. However, these surface proxies tend to have a seasonal bias toward spring/summer and thus only provide a discrete snapshot of surface conditions during one season. Furthermore, sea surface temperature proxies can be influenced by additional confounding variables resulting in markedly different Holocene temperature reconstructions. Here, we expand Iceland's marine paleoclimate toolkit with TEX86L: a temperature proxy based on the distribution of archaeal glycerol dibiphytanyl glycerol tetraether (GDGT) lipids. We develop a local Icelandic calibration from 21 surface sediment samples covering a wide environmental gradient across Iceland's insular shelves. Locally calibrated GDGT results demonstrate that (1) TEX86L reflects winter subsurface (0–200 m) temperatures on the North Iceland Shelf and (2) our calibration produces more realistic temperature estimates with substantially lower uncertainty (S.E. ±4 °C) over global calibrations. We then apply this new calibration to a high‐resolution marine sediment core (last millennium) collected from the central NIS with age control constrained by 14C‐dated mollusks. To test the veracity of the GDGT subsurface temperatures, we analyze quartz and calcite wt% and a series of highly branched isoprenoid alkenes, including the sea ice biomarker IP25, from the same core. The sediment records demonstrate that the development of thick sea ice during the Little Ice Age warmed the subsurface due to winter insulation. Importantly, this observation reflects a seasonal component of the sea ice/ocean feedback to be considered for the nonlinear cooling of the Little Ice Age in and around Iceland.Harvati, K., R?ding, C., Bosman, A.M., Karakostis, F.A., Grün, R., Stringer, C., Karkanas, P., Thompson, N.C., Koutoulidis, V., Moulopoulos, L.A., Gorgoulis, V.G., Kouloukoussa, M., 2019. Apidima Cave fossils provide earliest evidence of Homo sapiens in Eurasia. Nature 571, 500-504. fossilized human crania (Apidima 1 and Apidima 2) from Apidima Cave, southern Greece, were discovered in the late 1970s but have remained enigmatic owing to their incomplete nature, taphonomic distortion and lack of archaeological context and chronology. Here we virtually reconstruct both crania, provide detailed comparative descriptions and analyses, and date them using U-series radiometric methods. Apidima 2 dates to more than 170 thousand years ago and has a Neanderthal-like morphological pattern. By contrast, Apidima 1 dates to more than 210 thousand years ago and presents a mixture of modern human and primitive features. These results suggest that two late Middle Pleistocene human groups were present at this site—an early Homo sapiens population, followed by a Neanderthal population. Our findings support multiple dispersals of early modern humans out of Africa, and highlight the complex demographic processes that characterized Pleistocene human evolution and modern human presence in southeast Europe.He, S., Li, Y., Feng, Y., Ho, S., Ravanbakhsh, S., Chen, W., Póczos, B., 2019. Learning to predict the cosmological structure formation. Proceedings of the National Academy of Sciences 116, 13825-13832.: To understand the evolution of the Universe requires a concerted effort of accurate observation of the sky and fast prediction of structures in the Universe. N-body simulation is an effective approach to predicting structure formation of the Universe, though computationally expensive. Here, we build a deep neural network to predict structure formation of the Universe. It outperforms the traditional fast-analytical approximation and accurately extrapolates far beyond its training data. Our study proves that deep learning is an accurate alternative to the traditional way of generating approximate cosmological simulations. Our study shows that one can use deep learning to generate complex 3D simulations in cosmology. This suggests that deep learning can provide a powerful alternative to traditional numerical simulations in cosmology.Abstract: Matter evolved under the influence of gravity from minuscule density fluctuations. Nonperturbative structure formed hierarchically over all scales and developed non-Gaussian features in the Universe, known as the cosmic web. To fully understand the structure formation of the Universe is one of the holy grails of modern astrophysics. Astrophysicists survey large volumes of the Universe and use a large ensemble of computer simulations to compare with the observed data to extract the full information of our own Universe. However, to evolve billions of particles over billions of years, even with the simplest physics, is a daunting task. We build a deep neural network, the Deep Density Displacement Model (D3M), which learns from a set of prerun numerical simulations, to predict the nonlinear large-scale structure of the Universe with the Zel’dovich Approximation (ZA), an analytical approximation based on perturbation theory, as the input. Our extensive analysis demonstrates that D3M outperforms the second-order perturbation theory (2LPT), the commonly used fast-approximate simulation method, in predicting cosmic structure in the nonlinear regime. We also show that D3M is able to accurately extrapolate far beyond its training data and predict structure formation for significantly different cosmological parameters. Our study proves that deep learning is a practical and accurate alternative to approximate 3D simulations of the gravitational structure formation of the Universe.He, Z., Zhang, M., Ning, Z., Guo, C., Zhang, C., Du, J., 2019. Genetic quantitative techniques combined with continuous electromagnetic profiling to identify subtle oil and gas reservoirs. Geomicrobiology Journal 36, 705-714. reservoir exploration could not be commonly carried out by costly conventional methods especially when subtle reservoirs are becoming smaller in surfaces and reserves. The epochal genetic quantitative techniques were proved to be suitable for the subtle reservoir prospecting, but the anomaly grade classification method did not match the quantitative data qualitative dividing. And the combination of genetic quantitative techniques and geophysical exploration methods to the prospecting application for subtle reservoirs still need more studies. For the questions, 194 topsoil samples and 237.05?km continuous electromagnetic profiling (CEMP) lines were arranged in typical subtle reservoirs in the Suganhu Basin. The realtime-PCR technique was used to get methanotrophic, propanotrophic functional gene pmoA and prmA quantitative data. The results showed that the classification method using cumulative probability distribution curves with regression analyses could be used to classify the genetic quantitative anomalies by the equation of y = az. The genetic quantitative anomalies and source strata thickness showed positive correlation along the section lines in the east of study areas. Integrated studies between genetic quantitative anomalies and CEMP results in the stereoscopic direction indicated three promising areas in the Suganhu Basin. This research is expected to be extended to the same type of reservoirs prospecting work.Held, M., Ka?par, O., Edwards, C., Nicolau, D.V., 2019. Intracellular mechanisms of fungal space searching in microenvironments. Proceedings of the National Academy of Sciences 116, 13543-13552.: Many filamentous fungi colonizing animal or plant tissue, waste matter, or soil must find optimal paths through the constraining geometries of their microenvironment. Imaging of live fungal growth in custom-built microfluidics structures revealed the intracellular mechanisms responsible for this remarkable efficiency. In meandering channels, the Spitzenk?rper (an assembly of vesicles at the filament tip) acted like a natural gyroscope, conserving the directional memory of growth, while the fungal cytoskeleton organized along the shortest growth path. However, if an obstacle could not be negotiated, the directional memory was lost due to the disappearance of the Spitzenk?rper gyroscope. This study can impact diverse environmental, industrial, and medical applications, from fungal pathogenicity in plants and animals to biology-inspired computation.Abstract: Filamentous fungi that colonize microenvironments, such as animal or plant tissue or soil, must find optimal paths through their habitat, but the biological basis for negotiating growth in constrained environments is unknown. We used time-lapse live-cell imaging of Neurospora crassa in microfluidic environments to show how constraining geometries determine the intracellular processes responsible for fungal growth. We found that, if a hypha made contact with obstacles at acute angles, the Spitzenk?rper (an assembly of vesicles) moved from the center of the apical dome closer to the obstacle, thus functioning as an internal gyroscope, which preserved the information regarding the initial growth direction. Additionally, the off-axis trajectory of the Spitzenk?rper was tracked by microtubules exhibiting “cutting corner” patterns. By contrast, if a hypha made contact with an obstacle at near-orthogonal incidence, the directional memory was lost, due to the temporary collapse of the Spitzenk?rper–microtubule system, followed by the formation of two “daughter” hyphae growing in opposite directions along the contour of the obstacle. Finally, a hypha passing a lateral opening in constraining channels continued to grow unperturbed, but a daughter hypha gradually branched into the opening and formed its own Spitzenk?rper–microtubule system. These observations suggest that the Spitzenk?rper–microtubule system is responsible for efficient space partitioning in microenvironments, but, in its absence during constraint-induced apical splitting and lateral branching, the directional memory is lost, and growth is driven solely by the isotropic turgor pressure. These results further our understanding of fungal growth in microenvironments relevant to environmental, industrial, and medical applications.Heller, R., 2019. Decryption of messages from extraterrestrial intelligence using the power of social media – The SETI Decrypt Challenge. International Journal of Astrobiology 18, 296-303. the advent of modern astronomy, humans might now have acquired the technological and intellectual requirements to communicate with other intelligent beings beyond the solar system, if they exist. Radio signals have been identified as a means for interstellar communication about 60 years ago. And the Square Kilometer Array will be capable of detecting extrasolar radio sources analogous to terrestrial high-power radars out to several tens of light years. The ultimate question is: will we be able to understand the message or, vice versa, if we submit a message to extraterrestrial intelligence first, how can we make sure that they will understand us? Here I report on the largest blind experiment of a pretend radio message received on Earth from beyond the solar system. I posted a sequence of about two million binary digits (‘0’ and ‘1’) to the social media that encoded a configuration frame, two slides with mathematical content and four images along with spatial and temporal information about their contents. Six questions were asked that would need to be answered to document the successful decryption of the message. Within a month after the posting, over 300 replies were received in total, including comments and requests for hints, 66 of which contained the correct solutions. About half of the solutions were derived fully independently, the other half profited from public online discussions and spoilers. This experiment demonstrates the power of the world wide web to help interpreting possible future messages from extraterrestrial intelligence and to test the decryptability of our own deliberate interstellar messages.Hendriks, L., Hajdas, I., Ferreira, E.S.B., Scherrer, N.C., Zumbühl, S., Smith, G.D., Welte, C., Wacker, L., Synal, H.-A., Günther, D., 2019. Uncovering modern paint forgeries by radiocarbon dating. Proceedings of the National Academy of Sciences 116, 13210-13214.: Can radiocarbon (14C) dating uncover modern forgeries? Radiocarbon dating has the potential to answer the question of when an artwork was created, by providing a time frame of the material used. In this study we show that with two microsamples (<500 μg), from both the canvas and the paint layer itself, a modern forgery could be identified. The canvas dating is consistent with the purported attribution to the 19th century; however, the 14C age gained on the paint contradicts this as it offers clear evidence for a post-1950 creation. Thus the additional dating of the paint reveals the forger’s scheme where the repainting of an appropriately aged canvas was used to convey the illusion of authenticity.Abstract: Art forgeries have existed since antiquity, but with the recent rapidly expanding commercialization of art, the approach to art authentication has demanded increasingly sophisticated detection schemes. So far, the most conclusive criterion in the field of counterfeit detection is the scientific proof of material anachronisms. The establishment of the earliest possible date of realization of a painting, called the terminus post quem, is based on the comparison of materials present in an artwork with information on their earliest date of discovery or production. This approach provides relative age information only and thus may fail in proving a forgery. Radiocarbon (14C) dating is an attractive alternative, as it delivers absolute ages with a definite time frame for the materials used. The method, however, is invasive and in its early days required sampling tens of grams of material. With the advent of accelerator mass spectrometry (AMS) and further development of gas ion sources (GIS), a reduction of sample size down to microgram amounts of carbon became possible, opening the possibility to date individual paint layers in artworks. Here we discuss two microsamples taken from an artwork carrying the date of 1866: a canvas fiber and a paint chip (<200 ?g), each delivering a different radiocarbon response. This discrepancy uncovers the specific strategy of the forger: Dating of the organic binder delivers clear evidence of a post-1950 creation on reused canvas. This microscale 14C analysis technique is a powerful method to reveal technically complex forgery cases with hard facts at a minimal sampling impact.Hergarten, S., Wulf, G., Kenkmann, T., 2019. Comment on “Earth and Moon impact flux increased at the end of the Paleozoic”. Science 365, eaaw7471. et al. (Reports, 18 January 2019, p. 253) found a nonuniform distribution of crater ages on Earth and the Moon, concluding that the impact flux increased about 290 million years ago. We show that the apparent increase on Earth can be explained by erosion, whereas that on the Moon may be an artifact of their calibration ment on: S. Mazrouei, R. R. Ghent, W. F. Bottke, A. H. Parker, T. M. Gernon. Earth and Moon impact flux increased at the end of the Paleozoic. Science 363, 253–257 (2019). doi:10.1126/science.aar4058pmid:30655437Hermans, M., Lenstra, W.K., Hidalgo-Martinez, S., van Helmond, N.A.G.M., Witbaard, R., Meysman, F.J.R., Gonzalez, S., Slomp, C.P., 2019. Abundance and biogeochemical impact of cable bacteria in Baltic Sea sediments. Environmental Science & Technology 53, 7494-7503. depletion in coastal waters may lead to release of toxic sulfide from sediments. Cable bacteria can limit sulfide release by promoting iron oxide formation in sediments. Currently, it is unknown how widespread this phenomenon is. Here, we assess the abundance, activity, and biogeochemical impact of cable bacteria at 12 Baltic Sea sites. Cable bacteria were mostly absent in sediments overlain by anoxic and sulfidic bottom waters, emphasizing their dependence on oxygen or nitrate as electron acceptors. At sites that were temporarily reoxygenated, cable bacterial densities were low. At seasonally hypoxic sites, cable bacterial densities correlated linearly with the supply of sulfide. The highest densities were observed at Gulf of Finland sites with high rates of sulfate reduction. Microelectrode profiles of sulfide, oxygen, and pH indicated low or no in situ cable bacteria activity at all sites. Reactivation occurred within 5 days upon incubation of an intact sediment core from the Gulf of Finland with aerated overlying water. We found no relationship between cable bacterial densities and macrofaunal abundances, salinity, or sediment organic carbon. Our geochemical data suggest that cable bacteria promote conversion of iron monosulfides to iron oxides in the Gulf of Finland in spring, possibly explaining why bottom waters in this highly eutrophic region rarely contain sulfide in summer.Hippke, M., 2019. Interstellar communication. I. Maximized data rate for lightweight space-probes. International Journal of Astrobiology 18, 267-279. technological advances could make interstellar travel possible, using ultra-lightweight sails pushed by lasers or solar photon pressure, at speeds of a few per cent the speed of light. Obtaining remote observational data from such probes is not trivial because of their minimal instrumentation (gram scale) and large distances (pc). We derive the optimal communication scheme to maximize the data rate between a remote probe and home-base. The framework requires coronagraphic suppression of the stellar background at the level of 10?9 within a few tenths of an arcsecond of the bright star. Our work includes models for the loss of photons from diffraction, technological limitations, interstellar extinction and atmospheric transmission. Major noise sources are atmospheric, zodiacal, stellar and instrumental. We examine the maximum capacity using the ‘Holevo bound’ which gives an upper limit to the amount of information (bits) that can be encoded through a quantum state (photons), which is a few bits per photon for optimistic signal and noise levels. This allows for data rates of the order of bits per second per Watt from a transmitter of size 1 m at a distance of α Centauri (1.3 pc) to an earth-based large receiving telescope (E-ELT, 39 m). The optimal wavelength for this distance is 300 nm (space-based receiver) to 400 nm (earth-based) and increases with distance, due to extinction, to a maximum of ≈ 3 μm to the centre of the Galaxy at 8 kpc.Hodgins, G.W.L., 2019. Identifying art forgeries by radiocarbon dating microgram quantities of artists’ paints. Proceedings of the National Academy of Sciences 116, 13158-13160. people view paintings orthogonally. Usually, this is what the artist intended. However, historically and technically minded artists, art conservators, technical art historians, and indeed forgers are also interested in what paintings look like in microscopic cross-section. From this vantage point, other dimensions of the art are revealed. The stratigraphic perspective has obvious analogs in archaeology and geology, and the value for all 3 fields is that much can be learned from understanding the ordered arrangement of layers. The invention of radiocarbon dating in 1949 profoundly enriched stratigraphic methods employed in archaeology and geology by providing absolute dates from organic remains embedded within strata. In PNAS, Hendriks et al. (1) lay the groundwork for similar advances in the study of paintings. They report discordant radiocarbon dates within a painting inscribed with a written date of 1866. A canvas sample (the basal stratum) had a radiocarbon date consistent with the written age. However, carbon from the binding medium (the glue that holds pigment particles in place) in a single upper paint layer, contained elevated levels of radiocarbon that definitively indicated the paint was made after 1955.Radiocarbon (14C) is produced naturally from 14N in the earth’s upper atmosphere as a consequence of solar- and cosmic-ray bombardment. It oxidizes to carbon dioxide and mixes with the nonradioactive carbon dioxide pool. The incorporation of atmospheric carbon dioxide into plant molecules by photosynthesis and the recycling of those up the food chain by heterotrophs mixes 14C throughout the biosphere. The natural 14C production dynamic was perturbed by above-ground nuclear tests that took place between 1945 and 1963. These tests created additional atmospheric 14C. Elevated levels were first detectable in 1955, and by 1963, atmospheric 14C levels had nearly doubled. The 1963 Nuclear Test Ban Treaty prohibited further atmospheric … Hohrenk, L.L., Vosough, M., Schmidt, T.C., 2019. Implementation of chemometric tools to improve data mining and prioritization in LC-HRMS for nontarget screening of organic micropollutants in complex water matrixes. Analytical Chemistry 91, 9213-9220. of the most critical steps in nontarget screening of organic micropollutants (OMP) in complex environmental samples is handling of massive data obtained from liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS). Multivariate chemometric methods have brought about great progress in processing big data obtained from high-dimensional chromatographic systems. This work aimed at a comprehensive evaluation of two LC-Q-Orbitrap mass spectrometry full-scan data sets for target and nontarget screening of OMPs in drinking and wastewater samples, respectively. For each data set, following segmentation in the chromatographic dimension, at first multivariate curve resolution alternating least-squares (MCR-ALS) was employed for simultaneous resolution of global matrices. The chromatographic peaks and the corresponding mass spectra of OMP were fully resolved in the presence of highly co-eluting irrelevant and interfering peaks. Then partial least-squares-discriminant analysis was conducted to investigate the behavior of MCR-ALS components in different water classes and selection of most relevant components. Further prioritization of features in wastewater before and after ozonation and their reduction to 24 micropollutants were then obtained by univariate statistics. Two-way information retrieved from MCR-ALS of LC-MS1 data was also used to choose common precursor ions between recovered?and measured data through data-dependent acquisition. MS1 and MS2 spectral features were used for tentative identification of prioritized OMPs. This study indicates that the described strategy can be used as a promising tool to facilitate both feature selection through a reliable classification and interference-free identification of micropollutants in nontargeted and class-wise environmental studies.Holdsworth, R.E., McCaffrey, K.J.W., Dempsey, E., Roberts, N.M.W., Hardman, K., Morton, A., Feely, M., Hunt, J., Conway, A., Robertson, A., 2019. Natural fracture propping and earthquake-induced oil migration in fractured basement reservoirs. Geology 47, 700-704. geological processes that create fluid storage capacity and connectivity in global fractured basement reservoirs are poorly understood compared to conventional hydrocarbon plays. Hosting potentially multibillion barrels of oil, the upfaulted Precambrian basement of the Rona Ridge, offshore west of Shetland, UK, gives key insights into how such reservoirs form. Oil presence is everywhere associated with sub-millimeter- to meter-thickness mineralized fracture systems cutting both basement and local preseal cover sequences. Mineral textures and fluid inclusion geothermometry suggest a low-temperature (90–220 °C), near-surface hydrothermal system, as does the preservation of clastic sediments in the same fractures. These fills act as permanent props holding fractures open, forming long-term fissures in the basement that permit oil ingress and storage. Calcite-fill U-Pb dating constrains the onset of mineralization and contemporaneous oil charge to the Late Cretaceous. The additional preservation of oil-stained injected sediment slurries and silica gels along basement faults suggests that rift-related seismogenic faulting initiated lateral oil migration from Jurassic source rocks into the adjacent upfaulted ridge. Subsidence below sea level in the latest Cretaceous sealed the ridge with shales, and buoyancy-driven migration of oil into the preexisting propped fracture systems continued long after the cessation of rifting. These new observations provide an explanation for the viability of sub-unconformity fractured basement reservoirs worldwide, and have wider implications for subsurface fluid migration processes generally.Hollesen, J., Matthiesen, H., Fenger-Nielsen, R., Abermann, J., Westergaard-Nielsen, A., Elberling, B., 2019. Predicting the loss of organic archaeological deposits at a regional scale in Greenland. Scientific Reports 9, 9097. the Arctic, microbial degradation is actively destroying irreplaceable cultural and environmental records that have been preserved within archaeological deposits for millennia. Because it is not possible to survey the many sites in this remote part of the world, new methods are urgently needed to detect and assess the potential degradation. Here, we investigate organic deposits at seven archaeological sites located along the dominating west-east climatic gradient in West Greenland. We show that, regardless of age, depositional history and environmental conditions, all organic deposits are highly vulnerable to degradation. A state-of-the-art model that simulates the effect of future climate change on degradation indicates that 30–70% of the archaeological fraction of organic carbon (OC) could disappear within the next 80 years. This range reflects the variation within the climatic gradient and the future climate scenario applied (RCP 4.5 and RCP 8.5). All archaeological deposits are expected to experience a substantial loss, but the most rapid degradation seems to occur in the continental inland areas of the region, dominated by dry and warm summers. This suggests that organic remains from the Norse Viking Age settlers are especially under threat in the coming years.Hollis, C.J., Dunkley Jones, T., Anagnostou, E., Bijl, P.K., Cramwinckel, M.J., Cui, Y., Dickens, G.R., Edgar, K.M., Eley, Y., Evans, D., Foster, G.L., Frieling, J., Inglis, G.N., Kennedy, E.M., Kozdon, R., Lauretano, V., Lear, C.H., Littler, K., Lourens, L., Meckler, A.N., Naafs, B.D.A., P?like, H., Pancost, R.D., Pearson, P.N., R?hl, U., Royer, D.L., Salzmann, U., Schubert, B.A., Seebeck, H., Sluijs, A., Speijer, R.P., Stassen, P., Tierney, J., Tripati, A., Wade, B., Westerhold, T., Witkowski, C., Zachos, J.C., Zhang, Y.G., Huber, M., Lunt, D.J., 2019. The DeepMIP contribution to PMIP4: methodologies for selection, compilation and analysis of latest Paleocene and early Eocene climate proxy data, incorporating version 0.1 of the DeepMIP database. Geoscientific Model Development 12, 3149-3206. early Eocene (56 to 48 million years ago) is inferred to have been the most recent time that Earth's atmospheric CO2 concentrations exceeded 1000?ppm. Global mean temperatures were also substantially warmer than those of the present day. As such, the study of early Eocene climate provides insight into how a super-warm Earth system behaves and offers an opportunity to evaluate climate models under conditions of high greenhouse gas forcing. The Deep Time Model Intercomparison Project (DeepMIP) is a systematic model–model and model–data intercomparison of three early Paleogene time slices: latest Paleocene, Paleocene–Eocene thermal maximum (PETM) and early Eocene climatic optimum (EECO). A previous article outlined the model experimental design for climate model simulations. In this article, we outline the methodologies to be used for the compilation and analysis of climate proxy data, primarily proxies for temperature and CO2. This paper establishes the protocols for a concerted and coordinated effort to compile the climate proxy records across a wide geographic range. The resulting climate “atlas” will be used to constrain and evaluate climate models for the three selected time intervals and provide insights into the mechanisms that control these warm climate states. We provide version 0.1 of this database, in anticipation that this will be expanded in subsequent publications.Homann, M., 2019. Earliest life on Earth: Evidence from the Barberton Greenstone Belt, South Africa. Earth-Science Reviews 196, 102888. investigating the structure and diversity of Earth's record of life older than 3.2?Ga are restricted to two locations worldwide in which sedimentary rocks have escaped regional high-grade metamorphism and penetrative deformation: the Pilbara Craton of Western Australia and the Barberton Greenstone Belt in the Kaapvaal Craton of South Africa. This paper provides a South African perspective on the evidence of Paleoarchean life; a record that is often overlooked in the literature. It aims to summarize and critically review previously reported claims of early life in the BGB, gives an overview of the latest findings, and provides an outlook on potential future discoveries.The ~15?km thick, volcanic-sedimentary succession making up the Barberton Supergroup was deposited between 3.55 to ca. 3.20?Ga and can be subdivided in three stratigraphic units that provide a unique window into a diverse and widespread Paleoarchean microbial ecosystem landscape. Putative biosignatures occur almost throughout the entire BGB stratigraphy and range from carbonaceous cherts containing filamentous, spheroidal, and lenticular microstructures, traces of hydrothermal biofilms, photosynthetic microbial mats, remnants of pseudocolumnar stromatolites, and large, organic-walled spheroidal microfossils of currently unknown affinity. The BGB also contains one of the world's oldest known record of tufted microbial mats, which extensively colonized tidally-influenced, siliciclastic shorelines and were most likely formed by filamentous photosynthesizers. Other mat-associated biosignatures include silicified gas bubbles, domes and lenses that likely formed due to metabolic activity or the decay of buried organic matter. Some of these subsurface voids beneath the cohesive mats were inhabited by the earliest known forms of cavity-dwelling microbial communities that were probably dominated by chemotrophic or photosynthetic microbes. Recently discovered terrestrial microbial mats, once thriving in a fluvial-dominated setting, represent the oldest macroscopically-visible fossil traces of life on land, which is also supported by the occurrence of nearby paleosols that carry signals of biogenic sulfur fractionation.The wealth of preserved microbial biosignatures from marine, fluvial, hydrothermal, and possibly planktonic settings combined with the high spatial and temporal resolution of the Barberton Greenstone Belt deposits is truly exceptional, Consequently, the BGB deserves an equal level of attention and protection for future generations like its Australian counterpart.Hu, H., Hao, F., Guo, X., Yi, J., Shu, Z., Bao, H., Zhu, X., 2019. Effect of lithofacies on the pore system of over-mature Longmaxi shale in the Jiaoshiba area, Sichuan Basin, China. Marine and Petroleum Geology 109, 886-898. Longmaxi shale samples were collected from the Jiaoshiba area, China, where 5 billion cm3/year of shale gas is produced. The samples were evaluated to characterize the pores of various shale lithofacies. Three shale lithofacies were determined in the Jiaoshiba area, Sichuan Basin, China, based on the shale mineral components, namely, siliceous lithofacies (SL), argillaceous lithofacies (AL), and mixed lithofacies (ML). Field emission scanning electron microscopy (FE-SEM), which was performed under high and low voltages, GRI porosity, and carbon dioxide and nitrogen adsorptions were used to investigate the bulk-shale porosity, pore type, pore size, pore morphology, and pore volume among the lithofacies. Lithofacies affects the shale total organic carbon (TOC), bulk-shale porosity, pore size, shape, and volume. SL and ML contain high porosity, high TOC, abundant organic-matter (OM)-hosted pores, and high OM porosity, whereas AL contains few OM pores and has low TOC and low porosity. In the same lithofacies, samples with various TOC values exhibit different pore morphologies. For SL, the low-TOC sample has a round and elliptical OM pore forms, whereas the high-TOC samples show linear and narrow pore shapes that are probably associated with gas expulsion. In ML, the higher TOC is related to spherical or near-spherical OM pores, whereas the OM pore shape collapses in the low-TOC shale. Therefore, lithofacies affect the shale reservoir, and the characteristic and evolution of OM pores should be considered as constraints in shale lithofacies. In SL, sections with a higher TOC value are prime targets despite the high expulsion efficiency, which does not affect the enrichment and high yield of the shale gas. Sections of ML and low-TOC SL should be considered as potential targets because of higher OM porosity and low expulsion efficiency, whereas sections of AL engender risk in exploration and development of shale gas.Huang, J.-M., Baker, B.J., Li, J.-T., Wang, Y., 2019. New microbial lineages capable of carbon fixation and nutrient cycling in deep-sea sediments of the northern South China Sea. Applied and Environmental Microbiology 85, e00523-19.: Metagenomics of marine sediments has uncovered a broad diversity of new uncultured taxa and provided insights into their metabolic capabilities. Here, we detected microbial lineages from a sediment core near the Jiulong methane reef of the northern South China Sea (at 1,100-m depth). Assembly and binning of the metagenomes resulted in 11 genomes (>85% complete) that represented nine distinct phyla, including candidate phyla TA06 and LCP-89, Lokiarchaeota, Heimdallarchaeota, and a newly described globally distributed phylum (B38). The genome of LCP-89 has pathways for nitrate, selenate, and sulfate reduction, suggesting that they may be involved in mediating these important processes. B38 are able to participate in the cycling of hydrogen and selenocompounds. Many of these uncultured microbes may also be capable of autotrophic CO2 fixation, as exemplified by identification of the Wood-Ljungdahl (W-L) pathway. Genes encoding carbohydrate degradation, W-L pathway, Rnf-dependent energy conservation, and Ni/Fe hydrogenases were detected in the transcriptomes of these novel members. Characterization of these new lineages provides insight to the undescribed branches in the tree of life.Importance: Sedimentary microorganisms in the South China Sea (SCS) remain largely unknown due to the complexity of sediment communities impacted by continent rifting and extension. Distinct geochemical environments may breed special microbial communities including microbes that are still enigmatic. Functional inference of their metabolisms and transcriptional activity provides insight in the ecological roles and substrate-based interactivity of these uncultured Archaea and Bacteria. These microorganisms play different roles in utilizing inorganic carbon and scavenging diverse organic compounds involved in the deep-sea carbon cycle. The genomes recovered here contributed undescribed species to the tree of life and laid the foundation for future study on these novel phyla persisting in marginal sediments of the SCS.Huang, J., Yu, Z., Groom, J., Cheng, J.-F., Tarver, A., Yoshikuni, Y., Chistoserdova, L., 2019. Rare earth element alcohol dehydrogenases widely occur among globally distributed, numerically abundant and environmentally important microbes. The ISME Journal 13, 2005-2017. (Ln3+), known as rare earth elements, have recently emerged as enzyme cofactors, contrary to prior assumption of their biological inertia. Several bacterial alcohol dehydrogenases have been characterized so far that depend on Ln3+ for activity and expression, belonging to the methanol dehydrogenase clade XoxF and the ethanol dehydrogenase clade ExaF/PedH. Here we compile an inventory of genes potentially encoding Ln3+-dependent enzymes, closely related to the previously characterized XoxF and ExaF/PedH enzymes. We demonstrate their wide distribution among some of the most numerically abundant and environmentally important taxa, such as the phylogenetically disparate rhizobial species and metabolically versatile bacteria inhabiting world’s oceans, suggesting that reliance on Ln3+-mediated biochemistry is much more widespread in the microbial world than previously assumed. Through protein expression and analysis, we here more than double the extant collection of the biochemically characterized Ln3+-dependent enzymes, demonstrating a range of catalytic properties and substrate and cofactor specificities. Many of these enzymes reveal propensity for oxidation of methanol. This observation, in combination with genome-based reconstruction of methylotrophy pathways for select species suggests a much wider occurrence of this metabolic capability among bacterial species, and thus further suggests the importance of methylated compounds as parts of the global carbon cycling.Hudson, R.L., Coleman, F.M., 2019. Solid-state isomerization and infrared band strengths of two conformational isomers of cyclopropanecarboxaldehyde, a candidate interstellar molecule. ACS Earth and Space Chemistry 3, 1182-1188. least a dozen of the known interstellar molecules possess a formyl group (HCO), suggesting that other such species exist and await discovery in the interstellar medium. Here, we examine the mid-infrared (mid-IR) spectrum and selected physical properties of one such candidate, cyclopropanecarboxaldehyde, in amorphous ices. Mid-IR transmission spectra of solid cyclopropanecarboxaldehyde are presented for the first time and used to determine the cis-to-trans ratio of conformational isomers present in amorphous samples. The measured ratio is compared to one from an electron-diffraction study of the gas-phase compound. The cis-to-trans isomerization in the amorphous compound is followed, and the activation energy is determined. The first IR band strengths for solid cyclopropanecarboxaldehyde are reported. Also presented are refractive indices and densities at 15 K for amorphous forms of two related compounds, cyclopropane and cyclopropanemethanol. Two low-temperature reactions for the interstellar formation of cyclopropanecarboxaldehyde are briefly described.Hueter, A., Huck, S., Bodin, S., Heimhofer, U., Weyer, S., Jochum, K.P., Immenhauser, A., 2019. Central Tethyan platform-top hypoxia during Oceanic Anoxic Event 1a. Climate of the Past 15, 1327-1344. hypoxia in epeiric water masses is a common phenomenon of modern marine environments and causes mass mortality in coastal marine ecosystems. Here, we test the hypothesis that during the early Aptian, platform-top hypoxia temporarily established in some of the vast epeiric seas of the central Tethys and caused, combined with other stressors, significant changes in reefal ecosystems. Potentially interesting target examples include time intervals characterized by the demise of lower Aptian rudist–coral communities and the establishment of microencruster facies, as previously described from the central and southern Tethys and from the proto-North Atlantic domain. These considerations are relevant as previous work has predominantly focused on early Aptian basinal anoxia in the context of Oceanic Anoxic Event (OAE) 1a, whereas the potential expansion of the oxygen minimum zone (OMZ) in coeval shallow-water environments is underexplored. Well-known patterns in the δ13C record during OAE 1a allow for a sufficiently time-resolved correlation with previously studied locations and assignment to chemostratigraphic segments. This paper presents and critically discusses the outcome of a multi-proxy study (e.g., rare earth elements (REEs), U isotopes, and redox-sensitive trace elements) applied to lower Aptian shallow-water carbonates today exposed in the Kanfanar quarry in Istria, Croatia. These rocks were deposited on an extensive, isolated high in the central Tethys surrounded by hemipelagic basins. Remarkably, during chemostratigraphic segment C2, the depletion of redox-sensitive trace elements As, V, Mo, and U in platform carbonates, deposited in normal marine oxic waters, record the first occurrence of basinal, organic-rich sediment deposition in which these elements are enriched. During the C3 segment, seawater oxygen depletion established on the platform top as indicated by the patterns in Ce/Ce* and U isotopes. Shifts in redox-sensitive proxies coincide with the expansion of microencruster facies. Segment C4 witnesses the return to normal marine reefal faunas on the platform top and is characterized by patterns in redox-sensitive proxies typical of normal marine dissolved oxygen levels. It remains unclear, however, if platform-top hypoxia resulted from the expansion and upwelling of basinal, oxygen-depleted water masses or if spatially isolated, shallow hypoxic water bodies formed on the platform. Data shown here are relevant as they shed light on the driving mechanisms that control poorly understood faunal patterns during OAE 1a in the neritic realm and provide evidence on the intricate relation between basinal and platform-top water masses.Inglis, G.N., Naafs, B.D.A., Zheng, Y., Schellekens, J., Pancost, R.D., 2019. δ13C values of bacterial hopanoids and leaf waxes as tracers for methanotrophy in peatlands. Geochimica et Cosmochimica Acta 260, 244-256. emissions from peatlands contribute significantly to atmospheric CH4 levels and play an essential role in the global carbon cycle. The stable carbon isotopic composition (δ13C) of bacterial and plant lipids has been used to study modern and past peatland biogeochemistry, especially methane cycling. However, the small number of recent peatlands that have been characterised and the lack of consistency between target compounds means that this approach lacks a rigorous framework. Here, we undertake a survey of bacterial and plant lipid δ13C values in peatlands from different geographic regions, spanning a wide range of temperature (?8 to 27?°C) and pH (～3 to 8), to generate a reference dataset and probe drivers of isotopic variability. Within our dataset, the carbon fixation pathway predominantly determines leaf wax (n-alkane) δ13C values. Bacterial-derived C31 hopane δ13C values track those of leaf waxes but are relatively enriched (0 to 10‰), indicating a heterotrophic ecology and preferential consumption of 13C-enriched substrates (e.g. carbohydrates). In contrast, ≤C30 hopanoids can be strongly 13C-depleted and indicate the incorporation of isotopically light methane into the bacterial community, especially at near neutral pH (～5–6 pH). Previous analysis of Eocene sediments has suggested isotopic decoupling between C31 and ≤C30 hopanoid δ13C values. Our work suggests a globally widespread decoupling in recent peatlands; this persists despite the profound diversity of hopanoid producing bacteria and associated controls on their δ13C values and it has significant implications for future work. Re-analysis of published data from: (1) the (mid-to-early) Holocene and late Glacial, and (2) latest Paleocene and earliest Eocene in this revised context highlights that perturbations to the peatland methane cycle occurred during the past, and we envisage that this approach could provide unique (qualitative) insights into methane cycling dynamics throughout the geological record.Ishikawa, N.F., Butman, D., Raymond, P.A., 2019. Radiocarbon age of different photoreactive fractions of freshwater dissolved organic matter. Organic Geochemistry 135, 11-15. organic carbon (DOC) plays a major role in aquatic carbon cycling. In order to determine if DOC photolability was related to DOC age, we tested the effect of oxidation time using UV irradiation on natural radiocarbon concentrations (Δ14C) of DOC in six US rivers. The most photo-labile DOC was 14C youngest. After a 100?min UV irradiation, most DOC (>93%) was oxidized in two out of the six rivers studied. On the other hand, the other four rivers still had a considerable amount (>20%) of DOC resistant to UV oxidation, which showed lower Δ14C values than those of bulk DOC. We also found that the concentration and Δ14C value of bulk DOC are controlled by the photochemically intermediate fraction. The results suggest that 14C age of organic matter is not homogeneous within DOC, the degree of which may depend on the characteristics unique to rivers.Ivanova, A., Mitiurev, N., Cheremisin, A., Orekhov, A., Kamyshinsky, R., Vasiliev, A., 2019. Characterization of organic layer in oil carbonate reservoir rocks and its effect on microscale wetting properties. Scientific Reports 9, 10667. production of oil from carbonate reservoirs often requires the application of improved oil recovery technologies such as waterflooding. However, conventional waterflooding in carbonates usually results in low hydrocarbon recovery as most of these formations exhibit a complex pore throats structure and are mostly oil-wet. Therefore, improved insight into the causes of hydrophobic wetting behavior of such reservoirs is important for understanding the fluid distribution, displacement and enhancing recovery processes. The characterization of fluid-rock interactions is, however, challenging with existing laboratory methods, which are typically based on macroscale (mm) observations. In this experimental study, an advanced imaging technique, namely environmental scanning electron microscope, was applied for the comprehensive investigation of microscale (?m) wettability variations in carbonate rocks covered with organic layers. For the first time, the presence of organic layers on the sample was proved using energy dispersive X-ray mapping. Furthermore, the chemical bond of this layer and carbonate rock surfaces was determined using the transmission electron microscopy and electron energy-loss spectroscopy. The thickness of layer was estimated by using image processing software. These findings show that the application of combined microscopic techniques reveals important details about the reason of hydrophobic wetting properties of real carbonate rocks.Jahediesfanjani, H., Anderson, S.T., Warwick, P.D., 2019. Improving pressure-limited CO2 storage capacity in saline formations by means of brine extraction. International Journal of Greenhouse Gas Control 88, 299-310. carbon dioxide (CO2) storage capacity of saline formations may be constrained by reservoir pressure limitations. Brine extraction could be necessary to increase the CO2 storage capacity of a given formation, manage the extent of the underground CO2 plume and induced pressure front, and control the migration direction. To estimate the additional CO2 storage capacity of a saline formation that can be made accessible by extraction of in-situ brines, a three-dimensional (3D) generic cubic cell containing one CO2 injector in the middle surrounded by four brine extractors at each corner of the cell was assumed. A series of Tough2-ECO2N reservoir simulations were constructed with varying reservoir properties and run. Based on a series of scenarios, a mechanism was developed and demonstrated that resulted in derivation of a function to provide estimates of the ratio of total CO2 injection over the brine extraction rate for a given scenario. We selected multiple saline formations in U.S. basins and evaluated the potential to increase the combined dynamic CO2 storage capacity of the selected saline formations to over 1000?million metric tonnes per year (Mt/yr) of CO2 for 100 years by means of brine extraction. Such storage capacities may be adequate to accommodate the CO2 injection rates suggested for the United States under a “beyond two-degree Celsius scenario” (B2DS) that has been proposed to maintain global temperature rise to less than 2°C above pre-industrial reported levels. The results suggest that B2DS goals could be achieved with a volume ratio of brine extraction to CO2 injection as low as 1:4, which is far lower than the ratios that have been commonly assumed in the literature.Jakob, D.S., Wang, L., Wang, H., Xu, X.G., 2019. Spectro-mechanical characterizations of kerogen heterogeneity and mechanical properties of source rocks at 6 nm spatial resolution. Analytical Chemistry 91, 8883-8890. situ measurements of the chemical compositions and mechanical properties of kerogen help understand the formation, transformation, and utilization of organic matter in oil shale source rocks. However, the optical diffraction limit prevents attainment of nanoscale resolution using conventional spectroscopy and microscopy. Here, we developed peak force infrared (PFIR) microscopy for multimodal characterization of kerogen in organic shales. PFIR microscopy provides correlative infrared imaging, mechanical mapping, and broadband infrared spectroscopy capabilities with 6 nm spatial resolution within the frequency region of 2400–4000 cm–1. We have observed nanoscale heterogeneity in the chemical composition, aromaticity, and the level of maturity of the kerogens from source rocks obtained from the Eagle Ford shale play in Texas. The level of aromaticity of the kerogen positively correlates with the local mechanical moduli of the surrounding inorganic matrix, offering insights into the effect of kerogen heterogeneity on the nanoscale mechanical properties of the source rock. Our method and investigation advances the understanding toward the origin and transformation of kerogen in geological settings.Javed, F., Aslam, M., Rashid, N., Shamair, Z., Khan, A.L., Yasin, M., Fazal, T., Hafeez, A., Rehman, F., Rehman, M.S.U., Khan, Z., Iqbal, J., Bazmi, A.A., 2019. Microalgae-based biofuels, resource recovery and wastewater treatment: A pathway towards sustainable biorefinery. Fuel 255, 115826. utilization of natural fuel resources is threatening the global environment and societal sustainability. It triggers up the need for finding environmental-friendly and sustainable sources of energy. In this perspective, microalgae have emerged as a potential alternative. Microalgae are featured with distinct ability to provide ecological services and respond to the sustainability challenges simultaneously. Microalgae can fix atmospheric CO2, valorize waste resources and can produce a wide variety of bio-products. The promising features of microalgae pitch the idea of establishing a sustainable bio-refinery to draw multifaceted benefits and reinforce the objectives of resource efficient bio-economy. Unfortunately, in the last few years, preferential studies have been carried out to assess the potential of microalgae-based integrated bio-refinery. This review critically discussed the recent developments, opportunities, and barriers in the microalgae bio-industry and wastewater treatment. Particularly, microalgae potentials for biofuels and resources recovery are addressed towards sustainable biorefinery. Moreover, techno-economic and commercial viability of microalgae-led bio-refinery is reviewed to drive this technology towards practicality.Jiang, Y., Su, S., Liu, H., Wang, Y., Liu, J., 2019. Types of Cenozoic sedimentary subsags and their relationship with hydrocarbon enrichment in Bohai Bay Basin. Acta Petrolei Sinica 40, 635-645. are dozens of oil-bearing sags in Bohai Bay Basin, where multiple Cenozoic subsags with large sedimentary thickness and complete stratigraphic system are developed in each sag. Sedimentary subsag is the basic unit of oil and gas generation, migration and accumulation in the sag, controlling the plane distribution of oil and gas. There are great differences in the sedimentation and sedimentary characteristics of different types of subsags and hydrocarbon enrichment. Based on massive statistical data, this study analyzes the Cenozoic subsag types of Bohai Bay Basin and their relationships with oil and gas enrichment. The Cenozoic subsags in Bohai Bay Basin can be classified into early developmental, inherited developmental and late developmental types according to the activity rates of subsag-controlling faults and the sedimentary rates, burial history and denudation thickness of strata, which can be subdivided into 6 basic types of early type Ⅰ, early type Ⅱ, inherited type Ⅰ, inherited type Ⅱ, late type Ⅰ and late type Ⅱ. Various types of subsags are characterized with zonal distribution, different chief source rock series and hydrocarbon-generating periods. The fuzzy mathematics evaluation method was used to evaluate the hydrocarbon generation potentials of 54 subsags in the main sags of Bohai Bay Basin; they can be classified into 4 categories of hydrocarbon-generating subsags, namely category A, B, C and D. The developmental types of sedimentary subsag have certain corresponding relationships with the hydrocarbon-generating categories, i.e., category A and B subsags have strong hydrocarbon generation potentials, dominated by the inherited and late developmental subsags; category C and D subsags have moderate-poor hydrocarbon generation potentials, dominated by the early developmental subsags. The oil-rich sags are mainly composed of the inherited and late developmental, category A and B hydrocarbon-generating subsags, while the sags composed of the early developmental subsags have low hydrocarbon contents. The developmental types of subsags also have certain relations to the hydrocarbon migration distances and the enrichment strata:the category A hydrocarbon-bearing subsags with inherited and late developmental features have strong hydrocarbon supply capacities and long hydrocarbon migration distances. Therefore, for the inherited developmental subsags, oil and gas are enriched in the middle strata, while for the late developmental subsags, oil and gas can be enriched in the shallow strata; the early developmental subsags have weak hydrocarbon supplies and short hydrocarbon migration distances so that oil and gas mainly occur in the deep strata.Jiménez-González, M.A., ?lvarez, A.M., Carral, P., Almendros, G., 2019. Chemometric assessment of soil organic matter storage and quality from humic acid infrared spectra. Science of The Total Environment 685, 1160-1168. knowledge of biogeochemical mechanisms involved in soil organic carbon (SOC) storage is crucial to control its release to the atmosphere. In particular, the chemical composition of soil organic matter (SOM) plays an important role in the performance of the C storage and resilience in soils. The structural information provided by infrared spectroscopy (IR) of soil humic acid (HA) was used in the assessment of the C storage potential of 35 Spanish soils. Partial least squares (PLS) regression using the intensities of the points of the IR spectra of the HAs (4000–400?cm?1) as descriptors shows that a relationship exists between IR spectral pattern and the SOC content. This was also the case for E4 (humification index based on HA optical density at 465?nm). In addition, the chemical characteristics of the HAs correlated with the SOC levels were identified from digital data treatments of the IR spectra. Additional application of principal component analysis (PCA) and multidimensional scaling (MDS) suggested that bands assigned to carboxyl and amide structures were characteristic in HAs from soils with low C content, whereas HA spectra from soils with high C levels showed a conspicuous band pattern suggesting structural units of lignin from slightly transformed plant residues. The spectral profiles were analyzed in detail by an approach based on digital subtraction of IR spectra obtained by averaging those from HAs extracted from soils in the upper and lower quartiles of the SOC distribution. The results showed that significant relationships exist between the molecular composition of HAs and SOC levels and E4 values in a way in which aromatic, carboxyl and amide groups were predominant in HAs from soils with low SOC content, whereas lignin-derived structures were more characteristic of HAs from soils with high SOC content.Johnson, J.T., Carrick, I.J., Eakins, G.S., McLuckey, S.A., 2019. Mirror switching for high-resolution ion isolation in an electrostatic linear ion trap. Analytical Chemistry 91, 8789-8794. isolation was achieved via selective pulsing of the entrance and exit ion mirrors in an electrostatic linear ion trap mass spectrometer (ELIT). Mirror switching has been described previously as a method for capturing injected ions in ELIT devices. After ion trapping, mirror switching can be used as a method for ion isolation of successively narrower ranges of mass-to-charge (m/z) ratio. By taking advantage of the spatial separation of ions in an ELIT device, pulsing of the entrance and/or exit mirrors can release unwanted ions while continuing to store ions of interest. Furthermore, mirror switching can be repeated multiple times to isolate ions of very similar m/z values with minimal loss of the stored ions, as is demonstrated by the isolation of protonated l-glutamine and l-lysine (Δ m/z = 0.0364) from a mixture of the two amino acid ions and the isobaric mixture of [PC P-18:0/22:6] and [PC 19:0/19:0] (Δ m/z = 0.0575). As isolation is accomplished due to the spatial/temporal separation of ion packets within the ELIT, multiple reflection-time-of-flight (MR-TOF) mass spectra are shown to demonstrate separation in the ELIT at the time of isolation. An isolation resolution of greater than 35?000 fwhm is demonstrated here using a 5.25 in. ELIT. This resolution corresponds to the fwhm resolution necessary to reduce contaminant overlap of an equally abundant adjacent ion to 1% or less of the isolated ion intensity.Johnston, E.R., Hatt, J.K., He, Z., Wu, L., Guo, X., Luo, Y., Schuur, E.A.G., Tiedje, J.M., Zhou, J., Konstantinidis, K.T., 2019. Responses of tundra soil microbial communities to half a decade of experimental warming at two critical depths. Proceedings of the National Academy of Sciences 116, 15096-15105. permafrost thaw is expected to stimulate microbial release of greenhouse gases, threatening to further exacerbate climate change (cause positive feedback). In this study, a unique field warming experiment was conducted in Interior Alaska to promote surface permafrost degradation while maintaining uniform hydraulic conditions. After 5 winters of experimental warming by ～1 °C, microbial community shifts were observed at the receded permafrost/active layer boundary, which reflected more reduced conditions, including increased methanogenesis. In contrast, increased carbohydrate utilization (respiration) was observed at the surface layer. These shifts were relatable to observed increases in CO2 and CH4 release from this study site and the surrounding ecosystem. Collectively, our results demonstrate that microbial responses to warming are rapid and identify potential biomarkers that could be important in modeling.Abstract: Ongoing permafrost thaw is expected to stimulate microbial release of greenhouse gases, threatening to further exacerbate climate change (cause positive feedback). In this study, a unique field warming experiment was conducted in Interior Alaska to promote surface permafrost degradation while maintaining uniform hydraulic conditions. After 5 winters of experimental warming by ～1 °C, microbial community shifts were observed at the receded permafrost/active layer boundary, which reflected more reduced conditions, including increased methanogenesis. In contrast, increased carbohydrate utilization (respiration) was observed at the surface layer. These shifts were relatable to observed increases in CO2 and CH4 release from this study site and the surrounding ecosystem. Collectively, our results demonstrate that microbial responses to warming are rapid and identify potential biomarkers that could be important in modeling.Northern-latitude tundra soils harbor substantial carbon (C) stocks that are highly susceptible to microbial degradation with rising global temperatures. Understanding the magnitude and direction (e.g., C release or sequestration) of the microbial responses to warming is necessary to accurately model climate change. In this study, Alaskan tundra soils were subjected to experimental in situ warming by ～1.1 °C above ambient temperature, and the microbial communities were evaluated using metagenomics after 4.5 years, at 2 depths: 15 to 25 cm (active layer at outset of the experiment) and 45 to 55 cm (transition zone at the permafrost/active layer boundary at the outset of the experiment). In contrast to small or insignificant shifts after 1.5 years of warming, 4.5 years of warming resulted in significant changes to the abundances of functional traits and the corresponding taxa relative to control plots (no warming), and microbial shifts differed qualitatively between the two soil depths. At 15 to 25 cm, increased abundances of carbohydrate utilization genes were observed that correlated with (increased) measured ecosystem carbon respiration. At the 45- to 55-cm layer, increased methanogenesis potential was observed, which corresponded with a 3-fold increase in abundance of a single archaeal clade of the Methanosarcinales order, increased annual thaw duration (45.3 vs. 79.3 days), and increased CH4 emissions. Collectively, these data demonstrate that the microbial responses to warming in tundra soil are rapid and markedly different between the 2 critical soil layers evaluated, and identify potential biomarkers for the corresponding microbial processes that could be important in modeling.Jones, H.L., Lowery, C.M., Bralower, T.J., 2019. Delayed calcareous nannoplankton boom-bust successions in the earliest Paleocene Chicxulub (Mexico) impact crater. Geology 47, 753-756. Cretaceous-Paleogene (K-Pg; 66 Ma) mass extinction was caused by a bolide impact on the Yucatán platform near modern Chicxulub, Mexico. Calcareous nannoplankton, a dominant group of primary producers, were almost eradicated at this time. Post-impact nannoplankton assemblages from Northern Hemisphere sites were characterized by a short-lived series of high-dominance, low-diversity acmes (“boom-bust” successions), which likely represent an unstable post-impact environment. Although these boom-bust successions are a global signal, the mechanisms that controlled the taxonomic switchovers between acmes are currently unknown. Here, we present detailed analyses of calcareous nannoplankton and planktic foraminiferal assemblages in a new K-Pg section from the peak ring of the Chicxulub crater. We show that although nannoplankton assemblages resemble the typical series of acmes at Tethyan sites, the termination of the “disaster” acme in the crater is delayed by at least 500 k.y. The coincidence between shifts in the dominant planktic foraminiferal trophic group and switchovers in nannoplankton boom-bust taxa suggests that this series of acmes may represent a gradual trend toward oligotrophy driven by the global restoration of biological pump efficiency. Thus, the global diachroneity of boom-bust successions likely reflects the differential pacing of biological pump restoration between oceanic basins and settings.Jordan, S.F., O'Reilly, S.S., Praeg, D., Dove, D., Facchin, L., Romeo, R., Szpak, M., Monteys, X., Murphy, B.T., Scott, G., McCarron, S.S., Kelleher, B.P., 2019. Geophysical and geochemical analysis of shallow gas and an associated pockmark field in Bantry Bay, Co. Cork, Ireland. Estuarine, Coastal and Shelf Science 225, 106232. integrated geophysical, geological, and geochemical investigation of seabed fluid venting was carried out in upper Bantry Bay, a large marine inlet on the southwest coast of Ireland. The results provide evidence of the seafloor venting of gas rich fluids, resulting in the formation of a pockmark field identified here for the first time. The pockmarks occur in an area where sub-bottom profiles provide evidence of chimney-like features interpreted to record upward gas migration through Quaternary sediments to the seafloor. Three vibrocores up to 6?m long were acquired in water depths of 24–34?m, two from the pockmark field and one from outside. Methane of predominantly biogenic origin was quantified in all three cores by headspace analysis of sediment sub-samples. Well-defined sulfate methane transition zones (SMTZs) were observed in two of the cores, the shallowest (1.25?m below sea floor (mbsf)) inside the pockmark field and the other (3.75 mbsf) outside. It is likely that an SMTZ occurs at the location of the third core, also within the pockmark field, although deeper than the samples obtained during this study. Gas migration towards the seafloor is suggested to involve both diffuse pore fluid migration across wide areas and focused flow through the pockmarks, together driven by methanogenesis of pre-glacial lacustrine sediments preserved in a bedrock basin, and possible gas release from the Owenberg River Fault. Analysis of phospholipid fatty acids (PLFAs) and archaeal isoprenoid hydrocarbons was used to investigate the microbial ecology of these sediments. Anaerobic oxidation of methane (AOM) may play a role in controlling release of CH4 to the water column and atmosphere in this shallow gas setting, potentially mediated by syntrophic sulfate reducing bacteria (SRB) and anaerobic methanotrophic archaea (ANME).Kamatou, G., Sandasi, M., Tankeu, S., Vuuren, S.V., Viljoen, A., 2019. Headspace analysis and characterisation of South African propolis volatile compounds using GCxGC–ToF–MS. Revista Brasileira de Farmacognosia 29, 351-357. also known as “bee glue or bee resin” is a resinous mixture of bee saliva or bee wax and exudate from tree trunks and flowers, produced by honeybees. The composition of propolis varies depending on the vegetation the bees can access. It is therefore expected that propolis obtained from various localities may have different chemical profiles. In this study, the headspace volatiles of propolis (n = 39) collected from various locations in South Africa (Gauteng, Northern Cape and Western Cape Provinces) were explored for the first time using GCxGC–ToF–MS. Several GCxGC parameters were optimised including; incubation time, temperature and modulation period. Multivariate data analysis techniques (principal component and hierarchical cluster analyses) were applied on the GCxGC–ToF–MS data to investigate trends and clustering patterns within propolis samples. The results demonstrated hat headspace volatiles of propolis varied between locations. The volatile profiles were dominated by monoterpenes such as α-pinene (1.2–46.5%), β-pinene (2.0–21.8%), dihydrosabinene (trace-17.8%), limonene (trace-11.6%), p-cymene (0.1–5.3%), 1,8-cineole (0.1–11.0%), 2,7-dimethyl-3-octen-5-yne (trace-11.7%), E-β-ocimene (trace-17.8%); octanal (trace-12.9%) styrene (trace-13.5%) and α-thujene (trace-11.0%). Principal component analysis revealed chemical variation between propolis from the varoious locations. The heatmap of the averages revealed dehydrosabinene, isopropentyltoluene, p-cymene, acetophenone and α-thujene as chemical markers for the Northern Cape propolis, while λ-terpinene, propanoic acid, furfural, 2-methoxy benzyl alcohol and hexanoic acid methylester were filtered out as markers for Gauteng propolis. The propolis samples originating from the Western Cape Province were dominated by prenal, cinnamaldehyde styrene, 1,8-cineole, decanal, prenyl acetate and butanoic acid. Using GCxGC–ToF–MS in combination with chemometrics, it was possible to profile headspace volatile constituents of propolis and further identify marker compounds that differentiate propolis from various Provinces in South Africa.Kaminski, J., Waller, B.M., Diogo, R., Hartstone-Rose, A., Burrows, A.M., 2019. Evolution of facial muscle anatomy in dogs. Proceedings of the National Academy of Sciences 116, 14677-14681.: Dogs were shaped during the course of domestication both in their behavior and in their anatomical features. Here we show that domestication transformed the facial muscle anatomy of dogs specifically for facial communication with humans. A muscle responsible for raising the inner eyebrow intensely is uniformly present in dogs but not in wolves. Behavioral data show that dogs also produce the eyebrow movement significantly more often and with higher intensity than wolves do, with highest-intensity movements produced exclusively by dogs. Interestingly, this movement increases paedomorphism and resembles an expression humans produce when sad, so its production in dogs may trigger a nurturing response. We hypothesize that dogs’ expressive eyebrows are the result of selection based on humans’ preferences.Abstract: Dogs were shaped during the course of domestication both in their behavior and in their anatomical features. Here we show that domestication transformed the facial muscle anatomy of dogs specifically for facial communication with humans. A muscle responsible for raising the inner eyebrow intensely is uniformly present in dogs but not in wolves. Behavioral data show that dogs also produce the eyebrow movement significantly more often and with higher intensity than wolves do, with highest-intensity movements produced exclusively by dogs. Interestingly, this movement increases paedomorphism and resembles an expression humans produce when sad, so its production in dogs may trigger a nurturing response. We hypothesize that dogs’ expressive eyebrows are the result of selection based on humans’ preferences. Domestication shaped wolves into dogs and transformed both their behavior and their anatomy. Here we show that, in only 33,000 y, domestication transformed the facial muscle anatomy of dogs specifically for facial communication with humans. Based on dissections of dog and wolf heads, we show that the levator anguli oculi medialis, a muscle responsible for raising the inner eyebrow intensely, is uniformly present in dogs but not in wolves. Behavioral data, collected from dogs and wolves, show that dogs produce the eyebrow movement significantly more often and with higher intensity than wolves do, with highest-intensity movements produced exclusively by dogs. Interestingly, this movement increases paedomorphism and resembles an expression that humans produce when sad, so its production in dogs may trigger a nurturing response in humans. We hypothesize that dogs with expressive eyebrows had a selection advantage and that “puppy dog eyes” are the result of selection based on humans’ preferences.Kang, J., Fu, X., Jian, K., Li, X., 2019. Characteristics of the physical parameters and the evolution law of anthracite around the coalification jump: A case of the Jincheng and Guxu mining area, China. Energy Exploration & Exploitation 37, 1205-1226. investigate the physical properties of anthracite reservoirs with different metamorphic grades (Ro,max), 38 anthracite samples with an Ro,max value between 2.5 and 4.2% from the Guxu and Jincheng mining areas in China were selected to conduct proximate analysis and determine the macerals, pore size distribution, adsorption capacity, in-situ gas content and permeability. The results showed that a coalification jump at Ro,max=3.7% existed in the anthracite stage and greatly influenced the evolution of physical properties. Before the coalification jump point, a series of micropores and transition pores was formed during metamorphism, which increased the specific surface area of the reservoir. This phenomenon further increased the adsorption capacity and gas content. The formation of methane during metamorphism also provided a material basis for the enrichment of methane. After the coalification jump point, a decreased specific surface area was observed due to compaction of micropores and transition pores, thereby reducing the adsorption capacity and gas content. The end of gas generation also caused the gas content to increase with increasing Ro,max. The burial depth (overlying geostress) and metamorphism degree were key factors in controlling the permeability. The change in the metamorphic degree controlled the formation of microfractures, and the burial depth controlled the degree of fracture closure. The physical properties of reservoirs changed notably before and after the coalification jump point of high-rank coals. Therefore, more attention should be paid to coalification in the process of reservoir evaluation and development of high-rank coal reservoirs.Karthikeyan, S., Rodriguez-R, L.M., Heritier-Robbins, P., Kim, M., Overholt, W.A., Gaby, J.C., Hatt, J.K., Spain, J.C., Rosselló-Móra, R., Huettel, M., Kostka, J.E., Konstantinidis, K.T., 2019. “Candidatus Macondimonas diazotrophica”, a novel gammaproteobacterial genus dominating crude-oil-contaminated coastal sediments. The ISME Journal 13, 2129-2134. crude-oil biodegradation in sediments remains a challenge due in part to the lack of appropriate model organisms. Here we report the metagenome-guided isolation of a novel organism that represents a phylogenetically narrow (>97% 16S rRNA gene identity) group of previously uncharacterized, crude-oil degraders. Analysis of available sequence data showed that these organisms are highly abundant in oiled sediments of coastal marine ecosystems across the world, often comprising ~30% of the total community, and virtually absent in pristine sediments or seawater. The isolate genome encodes functional nitrogen fixation and hydrocarbon degradation genes together with putative genes for biosurfactant production that apparently facilitate growth in the typically nitrogen-limited, oiled environment. Comparisons to available genomes revealed that this isolate represents a novel genus within the Gammaproteobacteria, for which we propose the provisional name “Candidatus Macondimonas diazotrophica” gen. nov., sp. nov. “Ca. M. diazotrophica” appears to play a key ecological role in the response to oil spills around the globe and could be a promising model organism for studying ecophysiological responses to oil spills.Kashiyama, Y., Yokoyama, A., Shiratori, T., Hess, S., Not, F., Bachy, C., Gutierrez-Rodriguez, A., Kawahara, J., Suzaki, T., Nakazawa, M., Ishikawa, T., Maruyama, M., Wang, M., Chen, M., Gong, Y., Seto, K., Kagami, M., Hamamoto, Y., Honda, D., Umetani, T., Shihongi, A., Kayama, M., Matsuda, T., Taira, J., Yabuki, A., Tsuchiya, M., Hirakawa, Y., Kawaguchi, A., Nomura, M., Nakamura, A., Namba, N., Matsumoto, M., Tanaka, T., Yoshino, T., Higuchi, R., Yamamoto, A., Maruyama, T., Yamaguchi, A., Uzuka, A., Miyagishima, S., Tanifuji, G., Kawachi, M., Kinoshita, Y., Tamiaki, H., 2019. Taming chlorophylls by early eukaryotes underpinned algal interactions and the diversification of the eukaryotes on the oxygenated Earth. The ISME Journal 13, 1899-1910. eukaryote ecology is primarily sustained by oxygenic photosynthesis, in which chlorophylls play essential roles. The exceptional photosensitivity of chlorophylls allows them to harvest solar energy for photosynthesis, but on the other hand, they also generate cytotoxic reactive oxygen species. A risk of such phototoxicity of the chlorophyll must become particularly prominent upon dynamic cellular interactions that potentially disrupt the mechanisms that are designed to quench photoexcited chlorophylls in the phototrophic cells. Extensive examination of a wide variety of phagotrophic, parasitic, and phototrophic microeukaryotes demonstrates that a catabolic process that converts chlorophylls into nonphotosensitive 132,173-cyclopheophorbide enols (CPEs) is phylogenetically ubiquitous among extant eukaryotes. The accumulation of CPEs is identified in phagotrophic algivores belonging to virtually all major eukaryotic assemblages with the exception of Archaeplastida, in which no algivorous species have been reported. In addition, accumulation of CPEs is revealed to be common among phototrophic microeukaryotes (i.e., microalgae) along with dismantling of their secondary chloroplasts. Thus, we infer that CPE-accumulating chlorophyll catabolism (CACC) primarily evolved among algivorous microeukaryotes to detoxify chlorophylls in an early stage of their evolution. Subsequently, it also underpinned photosynthetic endosymbiosis by securing close interactions with photosynthetic machinery containing abundant chlorophylls, which led to the acquisition of secondary chloroplasts. Our results strongly suggest that CACC, which allowed the consumption of oxygenic primary producers, ultimately permitted the successful radiation of the eukaryotes throughout and after the late Proterozoic global oxygenation.Katende, A., Boyou, N.V., Ismail, I., Chung, D.Z., Sagala, F., Hussein, N., Ismail, M.S., 2019. Improving the performance of oil based mud and water based mud in a high temperature hole using nanosilica nanoparticles. Colloids and Surfaces A: Physicochemical and Engineering Aspects 577, 645-673. mud (OBM), a non-Newtonian fluid, is known for its superior performance in drilling complex wells as well as combating potential drilling complications. However, the good performance may degrade under certain circumstances especially because of the impact of chemical instability at an elevated temperature. The same phenomenon occurs for water-based mud (WBM) when it is used in drilling under high temperature conditions. To prevent this degradation from occurring, numerous studies on utilizing nanoparticles to formulate smart fluids for drilling operations are being conducted worldwide. Hence, this study aims to evaluate the performance of nanosilica (NS) as a fluid loss reducer and a rheological property improver in both OBM and WBM systems at high temperature conditions. This study focuses on the impacts of different nanosilica concentrations, varying from 0.5?ppb to 1.5?ppb, and different mud weights of 9?ppg and 12?pg as well as different aging temperatures, ranging from ambient temperature to 300?°F, on the rheological performance of OBM and WBM. All the rheological properties are measured at ambient temperature, and additionally tests, including lubricity, electrical stability, and high-pressure high-temperature filtration measurements, are conducted, and rheological models are obtained. The performance of nanosilica is then studied by comparing each of the nanosilica-enhanced mud systems with the corresponding basic mud system, taking the fluid loss and rheological properties as the benchmark parameters. Nanosilica shows a positive impact on OBM and WBM, as the presence of nanosilica in the mud systems can effectively improve almost all their rheological properties.Kawagucci, S., Seewald, J.S., 2019. Compositional and isotopic characteristics of hydrocarbons generated by a hydrothermal experiment simulating seafloor sediment alteration stepwise heating from 275 to 361°C at 30 MPa. Geochemical Journal 53, 281-291. conducted a laboratory hydrothermal experiment that simulated generation of low molecular-weight hydrocarbons during seafloor sediment alteration at 275-361°C and 30 MPa. The abundance and carbon and hydrogen stable isotope composition of low molecular weight thermogenic hydrocarbons in the fluids were determined. In general, the abundance of C1-C4 alkanes increased with time. The abundance of CH4 relative to C2-C4 alkanes as reflected by C1/C2+ ratios showed progressive increases from 1.2 to 4.3 with continued sediment heating. Alkenes were enriched in early phase and decreased with time. Carbon isotope ratios (δ13C) of thermogenic CH4 ranged between -42.0～-24.2‰. Carbon isotope ratios of C2H6 and C3H8 were similar to each other throughout the experiment (δ13C = -28.0～-20.3‰). In general, the carbon isotope ratios of C1-C4 alkanes were more close to those of substrate organic matter in larger carbon numbers and at later periods of the experiment. Hydrogen isotope ratios (δD) of CH4 varied from -325～-262‰, more negative than those expected at the isotope equilibrium between CH4 and H2O. Compared with results from the experiment, natural hydrothermal fluids show higher C1/C2+ ratio, more diverse δ13CCH4 values among the fields, higher δ13CC2 values, and higher δDCH4 values. The differences likely result from lower maturity of the experimental fluid and biogenic methane contribution to the natural fluids. Keenan, S.W., DeBruyn, J.M., 2019. Changes to vertebrate tissue stable isotope (δ15N) composition during decomposition. Scientific Reports 9, 9929. carcass decomposition, tissues undergo biochemical changes: Cells autolyze, enteric microbes ferment cellular products, and tissues degrade. Ultimately, decomposition fluids are released as an ephemeral nitrogen (N) and carbon source to the surrounding environment. However, decomposition fluids are δ15N-enriched relative to body tissues, leading to a disconnect between starting tissue composition and ending fluid composition. It remains largely unknown when or if tissues exhibit δ15N enrichment postmortem despite the importance of tissue stable isotopes to ecologists. To test our hypothesis that tissues would become progressively δ15N-enriched during decay, soft tissues and bone were collected from beaver carcasses at five time points. All soft tissues, including muscle, were significantly δ15N-enriched compared to fresh tissues, but were not as enriched as decomposition fluids. Tissue breakdown is initially dominated by anaerobic autolysis and later by microbe and insect infiltration, and partly explains decay fluid isotopic enrichment. We speculate that after rupture, preferential volatilization of δ15N-depleted compounds (especially ammonia) contributes to further enrichment. These results constrain the timing, rate, and potential mechanisms driving carcass isotopic enrichment during decay, and suggest that found carcasses (e.g., road kill) should be used with caution for inferring trophic ecology as decay can result in significant postmortem δ15N enrichment.Khatami, S., Deng, Y., Tien, M., Hatcher, P.G., 2019. Formation of water-soluble organic matter through fungal degradation of lignin. Organic Geochemistry 135, 64-70. is a major component of decaying terrestrial vegetation in soils and has been reported to contribute substantially to the formation of soil carbon humus and associated water extracts of soil. To better understand this process of humification, lignin from brown-rot degraded wood was subjected to a white-rot fungus (Phanerochaete chrysosporium) whose enzymes are particularly effective in lignin degradation. This enzymatic attack was monitored by ultrahigh resolution mass spectrometry of water soluble extracts of the fungal cultures. The molecular level characterizations showed that the P. chrysosporium fungi induced aromatic ring oxidations followed by ring opening, as expected. However, the production of new molecules, some of which are aliphatic, was also observed. These results are consistent with recent findings that hydroxyl radical attack of lignin involves ring opening reactions followed by electrocyclic condensations combined with radical scavenging/disproportionation reactions.Kim, C.S., 2019. Can stabilization and symmetry breakings give rise to life in the process of the universe evolution? International Journal of Astrobiology 18, 311-315. can be understood as the final process of the Universe's evolution, from Planck scale down to nuclear scale to atomic scale to molecular scale, then finally to bioscale, with the breaking of relevant symmetries at every step. By assuming the simplest definition of life, that life is just a molecular system which can reproduce itself (auto-reproducing molecular system – ARMS) and has such kinetic ability (kineto-molecular system), at least for its microscopic level, as to respond actively to its surrounding environments, we tried to explain the origin of life, taking the final step of the Universe evolution. We found a few clues for the origin of life, such as: (1) As the Universe expands and gets extremely cold, biogenesis can take place by ARMS, new level of stabilization may be achievable only at ‘locally cold places’ (LCPs), such as comets. (2) There must be the parity breaking in the bioscale stabilization process, which can be violated spontaneously, or dynamically by the van der Waals forces possible only at LCPs. (3) The rule of bioparity breaking is universal within the biohorizon. So we will find, e.g. only left-handed amino acids in all living beings dwelling within our Galaxy. (4) The idea of biogenesis through the bioscale stabilization in the evolution of the Universe looks very consistent with Panspermia hypothesis and supports it by providing a viable answer for life's origin at such LCPs.Kim, H., Park, C., Park, M.-H., Song, Y., 2019. Diagenetic study on the Neogene sedimentary basin as paleoenvironmental proxy data for an offshore CO2 storage project in Pohang Basin, South Korea. Marine Geology 416, 105977. the importance of reducing greenhouse gas emissions has attracted much attention, Pohang Basin has been identified as a CO2 geological sequestration test site in Korea. This study aims to provide a better understanding of the diagenetic history of Pohang Basin through mineralogical and microstructural analyses, with a focus on tectonic evolution in the reservoirs offshore of the Pohang Basin during the East Sea (Sea of Japan) opening in the Miocene. We focused on two sections in the core that are considered to be target layers for CO2 storage. Samples were analyzed for texture observation and chemical analysis. The major mineral components include quartz, feldspar, illite, chlorite, kaolinite and calcite, and the minor mineral components include pyrite, siderite, iron oxide, and titanium oxide. The detrital grains are composed of quartz and feldspar, and the primary pore is cemented with kaolinite (I), calcite, pyrite and chlorite. The analyzed chlorites are differentiated into five types by their textural characteristics, such as pore-filling (PF), pore-filling with kaolinite (PF-k), pore-lining (PL), replaced (RD), and detrital (DA) chlorites, and they were all categorized as either brunsvigite, diabantite, or ripidolite. Generally, the dissolution of feldspar is observed for all samples. The diagenetic temperature is estimated by chlorite geothermometry to be 170?°C on average, which is higher than the present temperature of Pohang Basin (55–60?°C). Considering all results together, the target layers have undergone diagenetic processes from early diagenesis (eogenesis) to late diagenesis (mesogenesis) and uplift-related diagenesis (telogenesis). After sedimentation of the Pohang Basin, kaolinite (I), calcite, and pyrite were cemented in the pore, and detrital mica was replaced with chlorite. As the burial depth increased, the dissolution of feldspar advanced. The high temperature resulting from the chlorite geothermometry could be influenced by the burial heat as source. Also, the Neogene volcanism and related tectonics (known as Eoil Orogeny) could become a heat source capable of high temperatures, and a high geothermal gradient and tectonically compressional environment may have influenced fluid flow. After the uplift, kaolinite (II) was precipitated in both an intergranular pore and intragranular pore as a result of dissolution. The effects of diagenesis, such as cementation and dissolution, in CO2 reservoir rocks, could be an important factor in assessing the appropriacy of predicting potential charge after injection in carbon capture and storage project.Kim, J., Kang, D., Lee, S.K., Kim, T.-Y., 2019. Deuterium oxide labeling for global omics relative quantification: Application to lipidomics. Analytical Chemistry 91, 8853-8863. novel quantitative mass spectrometric method based on partial metabolic deuterium oxide (D2O) labeling, named “Deuterium Oxide Labeling for Global Omics Relative Quantification (DOLGOReQ)”, was developed for relative quantification of lipids on a global scale. To assess the precision and robustness of DOLGOReQ, labeled and unlabeled lipids from HeLa cells were mixed in various ratios based on their cell numbers. Using in-house software developed for automated high-throughput data analysis of DOLGOReQ, the number of detectable mass isotopomers and the degree of deuterium labeling were exploited to filter out low quality quantification results. Quantification of an equimolar mixture of HeLa cell lipids exhibited high reproducibility and accuracy across multiple biological and technical replicates. Two orders of magnitude of effective dynamic range for reasonable relative quantification could be established with HeLa cells mixed from 10:1 to 1:10 ratios between labeled and unlabeled samples. The quantification precision of DOLGOReQ was also illustrated with lipids commonly detected in both positive and negative ion modes. Finally, quantification performance of DOLGOReQ was demonstrated in a biological sample by measuring the relative change in the lipidome of HeLa cells under normal and hypoxia conditions.Kim, J., Yu, S., Yun, S.-T., Kim, K.-H., Kim, J.-H., Shinn, Y.-J., Chae, G., 2019. CO2 leakage detection in the near-surface above natural CO2-rich water aquifer using soil gas monitoring. International Journal of Greenhouse Gas Control 88, 261-271. soil gas monitoring methods were applied above a natural low-level CO2 reservoir to locate natural CO2 leakage and assess effectiveness in monitoring geological carbon storage sites. The concentrations of the soil gas (N2, O2, and CO2) and carbon-13 isotopes of soil CO2 (δ13CCO2) were determined for ninety-four soil gas samples that were collected at a depth of ～60?cm. The CO2 flux was also measured at the same sampling locations. The 93 soil gas samples were divided into two groups: Group A with low soil CO2 concentrations and high δ13CCO2, which was influenced by the atmospheric air, and Group B with high soil CO2 concentrations and low δ13CCO2, which originated from microbial processes. Sample M17, which was close to a CO2-rich water well, had an exceptionally high soil CO2 (36.0% v/v), δ13CCO2 (-5.7‰), and flux (546.2?g/m2/d), indicating geogenic CO2 inflow to the soil layer and discharge through the surface. This study shows that conventional soil gas monitoring methods are useful for locating CO2 leakage. A dense grid soil CO2 sampling near wells and periodic investigations are crucial for further understanding of the CO2 flow paths in the soil layer.Kimmig, J., Strotz, L.C., Kimmig, S.R., Egenhoff, S.O., Lieberman, B.S., 2019. The Spence Shale Lagerst?tte: an important window into Cambrian biodiversity. Journal of the Geological Society 176, 609. Spence Shale Member of the Langston Formation is a Cambrian (Miaolingian: Wuliuan) Lagerst?tte in northeastern Utah and southeastern Idaho. It is older than the more well-known Wheeler and Marjum Lagerst?tten from western Utah, and the Burgess Shale from Canada. The Spence Shale shares several species with these younger deposits, yet it also contains a remarkable number of unique species. Because of its relatively broad geographical distribution, and the variety of palaeoenvironments and taphonomy, the fossil composition and likelihood of recovering weakly skeletonized (or soft-bodied) taxa varies across localities. The Spence Shale is widely acknowledged not only for its soft-bodied taxa, but also for its abundant trilobites and hyoliths. Recent discoveries from the Spence Shale include problematic taxa and provide insights about the nature of palaeoenvironmental and taphonomic variation between different localities.Supplementary material: A generic presence–absence matrix of the Spence Shale fauna and a list of the Spence Shale localities are available at: , R., 2019. The importance of being sufficiently realistic: a reply to Milan ?irkovi?. International Journal of Astrobiology 18, 10-13. do not believe that Professor ?irkovi?’s (2017) letter about my paper (Klee 2017) makes quite the case that he thinks it does, but then again I think that he misconstrues the spirit in which I wrote the paper. I wanted to take Thomas Nagel's claim that nothing that happens X billion years from now matters to us now and show that he is surely wrong if what happens is human expunction under the laws of physics. It is interesting to me that Professor ?irkovi? mostly passes over this core aspect of my argument (is it all that clear that something that far into the future should concern us?) and instead, incredibly enough, claims that the technology already exists, or shortly will exist, to fix all the hindrances to interstellar space travel that I canvass in my paper.K?bberich, M., Vance, D., 2019. Zn isotope fractionation during uptake into marine phytoplankton: Implications for oceanic zinc isotopes. Chemical Geology 523, 154-161. extreme scarcity of zinc (Zn) in the euphotic zone, coupled to deep enrichments, is consistent with biological uptake at the surface and regeneration at depth. In the context of a nutrient-type depth profile so clearly shaped by uptake into phytoplankton, the growing dataset for Zn isotopes presents a challenge. These data either show very minor isotope effects associated with extreme depletion, or enrichment of the light isotopes in the upper ocean. In contrast, culturing of eukaryotes in the laboratory suggests that light Zn isotopes are preferentially taken up into diatoms and coccoliths, implying that Zn depletion at the surface should be associated with extremely heavy residual dissolved signals.Here we present the first Zn isotope measurements for cultured marine cyanobacteria and compare these data to those for eukaryotic diatoms grown under identical conditions. Of the four cyanobacteria cultured, belonging to the genera Synechococcus and Prochlorococcus, three preferentially take up light Zn into the cell, with a variability that is not fundamentally different between pro- and eukaryotic phytoplankton. We also observe only very subtle differences between Zn/P and Fe/P uptake ratios for these three cyanobacteria groups relative to diatoms grown under the same conditions. A fourth strain exhibits preferential uptake of heavy Zn isotopes, and very high Zn/P ratios. Overall, we speculate that the observed variability among cyanobacteria may be related to the molecular structure of their photosynthetic light harvesting apparatus, adapted to significantly different light niches.These new and published culture data support the hypothesis that cellular δ66Zn in culture might largely be controlled by the organic ligands that bind Zn in the medium. Given that the Zn-binding ligands in the ocean have thermodynamic stability constants that are orders of magnitude smaller than the EDTA used in culture media, the surprisingly subtle Zn isotope variability in some parts of the surface ocean may be reconciled with culture data by the lesser, near zero, preference of these weaker complexes for heavy Zn isotopes.Konadu, K.T., Harrison, S.T.L., Osseo-Asare, K., Sasaki, K., 2019. Transformation of the carbonaceous matter in double refractory gold ore by crude lignin peroxidase released from the white-rot fungus. International Biodeterioration & Biodegradation 143, 104735. and carbonaceous matter in double refractory gold ore (DRGO) were bio-treated sequentially using an iron-oxidizing archaeon Acidianus brierleyi followed by lignin peroxidase-dominating crude enzymes released from the white-rot fungus Phanerochaete chrysosporium to significantly improve gold recovery from 24% to 92%. Transformation of the carbonaceous matter in the sequential bio-treatment was interpreted with Quantitative Evaluation of Materials by Scanning Electron Microscopy (QEMSCAN), Raman spectroscopy and three-dimensional fluorescence spectrometry. Firstly, microbiological sulfide oxidation did not affect carbonaceous matter but decreased the arsenic content in the solid residue, facilitating the following enzymatic reaction. Next, the crude enzymes predominantly decomposed the defect-bearing graphitic carbon into humic-like substances. The humic-like substances were not completely soluble under pH 4 but were instead retained in the solid residue as a part of a newly formed carbonaceous aluminosilicate (C–Si–Al) phase. Due to a wide pKa range of humic-like substances, it is proposed that at pH 4, electrostatic interaction between humic substances and illite, with and without heavy metals, might have enabled the agglomeration of fine aluminosilicate particles. Some gold grains trapped in C–Si–Al agglomerates were released by the dissolution of humic-like substances in 1?M NaOH, resulting in a further increase in gold recovery of approximately 15%.Kong, S., Huang, X., Li, K., Song, X., 2019. Adsorption/desorption isotherms of CH4 and C2H6 on typical shale samples. Fuel 255, 115632. and C2H6 are occupying components in shale gas. Determination of adsorption/desorption isotherms of CH4 and C2H6 on shale samples is significant for estimating the storage of shale resources in shale reservoirs. In this study, the thermogravimetric method is used to obtain the excess adsorption/desorption of CH4 and C2H6 on two typical shale samples. Simplified local density theory/Peng-Robinson equation of state (SLD-PR EOS) model is then applied to calculate the adsorbed density of CH4 and C2H6 on both shale samples, which is then applied to convert the measured excess adsorption into absolute adsorption values. Results show that C2H6 presents higher adsorption capacity than CH4 on shale samples, indicating the more affinity of C2H6 to the organic shale. Based on the predicted results from the SLD-PR EOS model, a reasonable agreement has been achieved with the measured adsorption isotherms, indicating the accuracy of the SLD-PR EOS model for predicting adsorption of CH4 and C2H6 on shale samples. In addition, the calculated adsorbed density of CH4 and C2H6 is a function of temperature and pressure, which agrees well with the results from the molecular simulations. The obtained absolute adsorption is always higher than the measured excess adsorption, emphasizing the importance of determination of adsorbed density in predicting the absolute adsorption of CH4 and C2H6 on shale. This study compares the adsorption/desorption behaviors of CH4 and C2H6 on typical shale samples, and more importantly, we propose a more efficient method, i.e., the SLD-PR EOS model, to calculate the absolute adsorption of CH4 and C2H6 on shale samples.Korshunova, T.Y., Chetverikov, S.P., Bakaeva, M.D., Kuzina, E.V., Rafikova, G.F., Chetverikova, D.V., Loginov, O.N., 2019. Microorganisms in the elimination of oil pollution consequences (Review). Applied Biochemistry and Microbiology 55, 344-354. data on the effect of oil and oil products on soil, soil microbiocenosis, and plant cover are summarized. Reclamation and its stages and the bioremediation of oil-contaminated soils with the use of biological products are described. The article discusses some techniques to accelerate hydrocarbon biodegradation in the soil environment, such as the use of biosurfactants and their microorganisms; the introduction of polyfunctional bacteria that are capable of pollutant destruction and diazotrophy; the introduction of psychrotolerant microorganisms under cold climate conditions; and the use of microbial-plant complexes.Kotarba, M.J., Sumino, H., Nagao, K., 2019. Origin of hydrocarbon and noble gases, carbon dioxide and molecular nitrogen in Devonian, Pennsylvanian and Miocene strata of the Polish Lublin and Ukrainian Lviv basins, southern part of the Upper Silesian Coal Basin and western part of the Carpathian Foredeep (Poland). Applied Geochemistry 108, 104371. natural gas samples were collected from Devonian, Pennsylvanian and Miocene strata of the Polish Lublin and Ukrainian Lviv basins, from the southern area of the Upper Silesian Coal Basin (USCB) and western part of the Carpathian Foredeep (CF) in Poland. The samples were analysed for the molecular composition and stable isotope compositions of gaseous hydrocarbons (CH4, C2H6 and C3H8) and CO2,N2, and noble gases (He, Ne, Ar, Kr, and Xe) in order to reveal the origin and migration pathways of these gases. Hydrocarbon gases and the majority of the of CO2 were generated during two stages of thermogenic processes from Type-II and II/III kerogens in the Lublin Basin, and during both thermogenic and microbial processes in the Lviv Basin. The thermogenic component was generated from Type-II kerogen. Coal-bed hydrocarbon gases accumulated in the Pennsylvanian strata of the southern part of the USCB, originated from both thermogenic and microbial processes. Isotopically light microbial methane may have migrated from Miocene (Upper Badenian) Skawina Formation of the CF to Carboniferous coal-bearing strata and/or might result from diffusion and adsorption-desorption processes during the migration of thermogenic gases from deeper lying coal seams through the microporous coal structure. Hydrocarbon gases and carbon dioxide which accumulated in the sandstone reservoirs of Upper Badenian Skawina Formation of the western part of the CF, most probably were generated from dispersed organic matter within the claystones and mudstones of these strata and at least partly migrated from the Carboniferous coal-bearing strata of the USCB. N2 could have been produced as a result of various biogenic and abiogenic processes, and contributed to the atmospheric component. Characteristic radiogenic 4He composition of the analysed gases suggest the accumulation of α-particles formed from U and Th radioactive decay in the crustal gas reservoirs. Radiogenic 40Ar and nucleogenic 21Ne with abundance ratios characteristic of crustal reservoirs were also observed. Addition of mantle-derived He to the gases from Miocene strata is evident from elevated 3He/4He ratios ranging between 0.2 and 1.6?×?10?6. A small contribution of Ne from the mantle along with He is also suggested by the slightly elevated 20Ne/22Ne ratios relative to atmosphere. The mantle component is most likely to have migrated from the upper mantle to the gas reservoirs through the deep-seated Bzie-Czechowice Fault Zone.Kovaleva, E., Zamyatin, D.A., Habler, G., 2019. Granular zircon from Vredefort granophyre (South Africa) confirms the deep injection model for impact melt in large impact structures. Geology 47, 691-694. Vredefort impact structure, South Africa, is a 2.02 Ga deeply eroded meteorite scar that provides an opportunity to study large impact craters at their lower stratigraphic levels. A series of anomalous granophyre dikes in the core of the structure are believed to be composed of an impact melt, which intruded downwards from the crater floor, exploiting fractures in basement rocks. However, the melt emplacement mechanisms and timing are not constrained. The granophyre dikes contain supracrustal xenoliths captured at higher levels, presently eroded. By studying these clasts and shocked minerals within, we can better understand the nature of dikes, magnitude of impact melt movement, conditions that affected target rocks near the impacted surface, and erosional rates. We report “former reidite in granular neoblastic” (FRIGN) zircon within a granite clast enclosed in the granophyre. High-pressure zircon transformation to reidite (ZrSiO4) and reversion to zircon resulted in zircon grains composed of fine neoblasts (～0.5–3 ?m) with two or three orthogonal orientations. Our finding provides new independent constraints on the emplacement history of Vredefort granophyre dikes. Based on the environment, where other FRIGN zircons are found (impact glasses and melts), the clast was possibly captured near the top of the impact melt sheet and transported to the lowermost levels of the structure, traveling some 8–10 km. Our finding not only provides the highest-pressure shock estimates thus far discovered in the Vredefort structure (≥30 GPa), but also shows that microscopic evidence of high shock pressures can be found within large eroded craters at their lowest stratigraphic levels.Kristensen, M., Christensen, P., Christensen, J.H., 2019. Optimization and validation of a derivatization method with boron trifluoride in ethanol for analysis of aromatic carboxylic acids in water. Journal of Chromatography A 1601, 21-26. (GC) analysis of carboxylic acids is limited by the high polarity and low volatility of most of these compounds. Boron trifluoride (BF3) mediated alkylation reactions is one of the most commonly used derivatization methods for making carboxylic acids GC compatible. A semi-automated BF3·EtOH (ethanol) derivatization method was optimized for comprehensive two-dimensional gas chromatography high-resolution mass spectrometry (GC?×?GC-HR MS) analysis of carboxylic acids in solid phase extraction (SPE) extracts of oil polluted water. The optimal derivatization method were found to be with addition of 300??L BF3·EtOH per 200??L sample and reaction at 75?°C for 24?hours. Derivatives of eight selected acids (aliphatic, mono- and di-aromatic) were stable over 12?hours with relative standard deviations (RSDs) of 2.0-10.7 %, the derivatization method was repeatable (RSDs of 3.2 - 17.2 %), detection limits (DL) and limit of detections (LODs) was in the range of DL?=?0.53-1.63?ppb and LOD?=?0.19-2.51?ppb for pure acid standards, and DL?=?0.18-3.41?ppb and LOD?=?0.28-5.46?ppb for matrix matched acid standards. Finally, the method was validated on the acidic fraction of a mixed anion-exchange SPE of oil polluted water. Thousands of degradation products from parent alkylated polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons, such as aliphatic acids and mono-, di- and tri- aromatic acids were analyzed by the applied method and compound groups were tentatively identified.Kuitems, M., van Kolfschoten, T., Tikhonov, A.N., van der Plicht, J., 2019. Woolly mammoth δ13C and δ15N values remained amazingly stable throughout the last ～50,000 years in north-eastern Siberia. Quaternary International 500, 120-127. range of the woolly mammoth (Mammuthus primigenius) covered the northern circumpolar region, over time varying in size and space due to changes in regional climatic conditions. The species survived multiple glacial cycles, but got extinct around the end of the last glacial, between ～21,000 and 4000 years ago. Stable carbon (δ13C) and nitrogen (δ15N) data of woolly mammoth fossils from western Eurasia and Alaska, show considerable variation during periods of global climatic change and towards time of regional extinction. In North-eastern Siberia, the woolly mammoth survived several millennia longer. The fossil record from North-eastern Siberia yields, therefore, crucial ecological information about the living conditions of the woolly mammoth and plays an important role in the debate about the cause of its extinction. The current dataset comprises an unprecedented amount of δ13C and δ15N data of directly radiocarbon-dated woolly mammoth skeletal samples from North-eastern Siberia, including numerous Holocene samples from Wrangel Island. This study shows that the δ13C and δ15N values of the woolly mammoth remained amazingly stable in this region throughout the last ～50,000 years of its existence.Kune?, P., Abraham, V., Herben, T., 2019. Changing disturbance-diversity relationships in temperate ecosystems over the past 12000?years. Journal of Ecology 107, 1678-1688. such as fires and grazing have major impacts on biodiversity. While it has been suggested that species richness is highest with intermediate levels of disturbance, currently there is no consensus due to an absence of data covering large temporal and spatial scales.We developed a new method to examine disturbance‐diversity relationships (DDR) using sedimentary pollen data linked with species’ disturbance ecology. We reconstructed disturbance and diversity dynamics in the region of the European temperate zone over the last 12,000 years and calculated DDR for 900‐year sequential temporal windows.Disturbance frequency was highest in the early and late Holocene, while remaining low in the mid‐Holocene. Diversity increased continuously from the start of the Holocene. Our results demonstrate that over the past 12,000 years DDR changed from hump‐shaped into monotonic increasing pattern. While both highly disturbed and undisturbed sites were strongly impoverished in the early Holocene, as species migrated, biodiversity levels have subsequently affected disturbance regimes with highly disturbed sites now being the highest in species richness.Synthesis. Land‐use changes in the last 4,000 years created an increasingly patchy landscape, allowing invasive species adapted to high‐frequency disturbance to migrate across the landscape. The link between high diversity and disturbed areas is relatively recent and may anticipate even greater disturbance frequencies in future. Our findings also support a hypothesis that species migration, and the structure of the species pool critically determines the response of biota to external factors such as disturbance. Laakso, T.A., Schrag, D.P., 2019. Methane in the Precambrian atmosphere. Earth and Planetary Science Letters 522, 48-54. methane production occurs in anoxic terrestrial wetlands and in sulfate depleted marine sediments. It has been suggested that methanogens may have flourished in the anoxic and sulfate-poor environments of the Precambrian ocean, generating large amounts of methane that would have accumulated in the atmosphere and warmed the early Earth. However, modern ferruginous and sulfate-poor environments such as Lake Matano are not very efficient at generating methane, converting only about 5% of organic carbon to CH4 despite the lack of alternative remineralization pathways. We apply this restriction to a simple model of marine carbon cycling in order to generate new estimates of methane concentrations in the Precambrian atmosphere. Our results suggest that, if the ancient biosphere were similarly inefficient, atmospheric methane concentrations did not exceed 1 ppm, or about twice the pre-industrial value, at any time during the Proterozoic. Following the evolution of oxygenic photosynthesis, the maximum methane concentration in the Archean atmosphere was order 100 ppm, but no more than 1 ppm if steady state oxygen concentrations were greater than 10?8 present atmospheric levels. Substantially larger methane concentrations are only possible before the evolution of oxygenic photosynthesis.Lai, J., Pang, X., Xu, F., Wang, G., Fan, X., Xie, W., Chen, J., Qin, Z., Zhou, Z., 2019. Origin and formation mechanisms of low oil saturation reservoirs in Nanpu Sag, Bohai Bay Basin, China. Marine and Petroleum Geology 110, 317-334. oil saturation reservoirs are increasingly encountered in superimposed sedimentary basins, however, the uncertainty about the origin of the low oil saturation becomes a major factor impeding further hydrocarbon exploration. Routine core analysis, (fluorescence) thin section, scanning electron microscope (SEM) and nuclear magnetic resonance (NMR) measurements were used to understand the characteristics and formation mechanisms of the low oil saturation reservoirs in the Paleogene Dongying Formation in the Nanpu sag, Bohai Bay Basin, East China. Irreducible water saturation was determined from sealed coring oil saturation testing and NMR logs. Wide ranges of porosity and permeability were observed, and the samples with moderate reservoir quality have the best oil bearing property. Low oil saturation oil layers are characterized by low oil saturation (<50%) but high content of irreducible water (>40%), with only oil being produced whereas no water or only minor amounts of water being produced. The low oil saturation oil-water reservoirs refer to the low oil saturation layers in which both oil and water will be produced during oil testing.Irreducible water saturation increases with total clay content, with the authigenic clays (kaolinite, illite and mixed layer illite/smectite) blocking pore spaces, and resulting in high irreducible water saturations. Fluorescence thin sections combined with NMR measurements show that the NMR T2 (transversal relaxation time) distribution is uni-modal, with large intergranular pores being rare. Almost the entire pore-size range is oil bearing for the low oil saturation oil reservoirs. The large intergranular pores are fluorescence-free, while the intragranular dissolution pores and micropores emit fluorescence in the low oil saturation oil-water reservoirs. The NMR T2 distribution of low oil saturation oil-water reservoirs is bi-modal and right-skewed, and the main oil-bearing NMR pore size distribution ranges from 0.1 to 100?ms. High irreducible water content was encountered in the low oil saturation oil reservoirs and low oil saturation oil-water reservoirs, and only part of the large intergranular pores are oil saturated, and in some cases only the intragranular pores are saturated with oils forming low oil saturation oil reservoirs. The results help improve the knowledge of characteristics and formation of the low oil saturation oil layers, and could provide insights in enhancing oil recovery.Lammer, H., Spro?, L., Grenfell, J.L., Scherf, M., Fossati, L., Lendl, M., Cubillos, P.E., 2019. The role of N2 as a geo-biosignature for the detection and characterization of Earth-like habitats. Astrobiology 19, 927-950. the Archean, N2 has been a major atmospheric constituent in Earth's atmosphere. Nitrogen is an essential element in the building blocks of life; therefore, the geobiological nitrogen cycle is a fundamental factor in the long-term evolution of both Earth and Earth-like exoplanets. We discuss the development of Earth's N2 atmosphere since the planet's formation and its relation with the geobiological cycle. Then we suggest atmospheric evolution scenarios and their possible interaction with life-forms: first for a stagnant-lid anoxic world, second for a tectonically active anoxic world, and third for an oxidized tectonically active world. Furthermore, we discuss a possible demise of present Earth's biosphere and its effects on the atmosphere. Since life-forms are the most efficient means for recycling deposited nitrogen back into the atmosphere at present, they sustain its surface partial pressure at high levels. Also, the simultaneous presence of significant N2 and O2 is chemically incompatible in an atmosphere over geological timescales. Thus, we argue that an N2-dominated atmosphere in combination with O2 on Earth-like planets within circumstellar habitable zones can be considered as a geo-biosignature. Terrestrial planets with such atmospheres will have an operating tectonic regime connected with an aerobic biosphere, whereas other scenarios in most cases end up with a CO2-dominated atmosphere. We conclude with implications for the search for life on Earth-like exoplanets inside the habitable zones of M to K stars.Lan, H., Holopainen, J., Hartonen, K., Jussila, M., Ritala, M., Riekkola, M.-L., 2019. Fully automated online dynamic in-tube extraction for continuous sampling of volatile organic compounds in air. Analytical Chemistry 91, 8507-8515. and time-dependent information (e.g., chemical composition, concentration) of volatile organic compounds (VOCs) in atmospheric, indoor, and breath air is essential to understand the fundamental science of the atmosphere, air quality, and diseases diagnostic. Here, we introduced a fully automated online dynamic in-tube extraction (ITEX)–gas chromatography/mass spectrometry (GC/MS) method for continuous and quantitative monitoring of VOCs in air. In this approach, modified Cycle Composer software and a PAL autosampler controlled and operated the ITEX preconditioning, internal standard (ISTD) addition, air sampling, and ITEX desorption sequentially to enable full automation. Air flow passed through the ITEX with the help of an external pump, instead of plunger up–down strokes, to allow larger sampling volumes, exhaustive extraction, and consequently lower detection limits. Further, in order to evaluate the ITEX system stability and to develop the corresponding quantitative ITEX method, two laboratory-made permeation systems (for standard VOCs and ISTD) were constructed. The stability and suitability of the developed system was validated with a consecutive 19 day atmospheric air campaign under automation. By using an electrospun polyacrylonitrile nanofibers packed ITEX, selective extraction of some VOCs and durability of over 1500 extraction and desorption cycles were achieved. Especially, the latter step is critically important for on-site long-term application at remote regions. This ITEX method provided 2–3 magnitudes lower quantitation limits than the headspace dynamic ITEX method and other needle trap methods. Our results proved the excellence of the fully automated online dynamic ITEX–GC/MS system for tracking VOCs in the atmospheric air.Lan, L., Yang, F., Zhang, L., Yang, W., Wu, F., Xu, Z., Liu, Y., Yue, K., Ni, X., Li, H., Liao, S., Liu, Y., Chen, Y., Tan, B., 2019. Non-target effects of naphthalene on the soil microbial biomass and bacterial communities in the subalpine forests of western China. Scientific Reports 9, 9811. is a biocide of soil fauna, particularly of soil arthropods, that has been widely applied to test the functional roles of soil fauna in soil processes. However, whether the use of naphthalene to expel soil fauna has a non-target effect on soil bacteria in subalpine forests remains unclear. We conducted a naphthalene treatment experiment to explore the effects of naphthalene on the soil bacterial community in subalpine forest soil. The results suggested that naphthalene treatment (at 100?g.m?2 per month) significantly increased the abundances of total bacterial, gram-positive bacterial and gram-negative bacterial phospholipid fatty acids (PLFA) and did not change the microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) or MBC/MBN ratio. Moreover, a total of 1038 operational taxonomic units (OTUs) were detected by Illumina MiSeq sequencing analysis. Proteobacteria, Actinobacteria, and Acidobacteria Chloroflexi were the dominant phyla, and Bradyrhizobium was the most abundant genus. The naphthalene treatment did not affect soil bacterial diversity or community structure. Overall, these results demonstrated that the naphthalene treatment had non-target effects on the active bacterial community abundance but not the soil bacterial community structure. Thus, the non-target effects of naphthalene treatment should be considered before using it to expel soil fauna.Landis, M.S., Berryman, S.D., White, E.M., Graney, J.R., Edgerton, E.S., Studabaker, W.B., 2019. Use of an epiphytic lichen and a novel geostatistical approach to evaluate spatial and temporal changes in atmospheric deposition in the Athabasca Oil Sands Region, Alberta, Canada. Science of The Total Environment 692, 1005-1021. and spatial atmospheric deposition trends of elements to the boreal forest surrounding bitumen production operations in the Athabasca Oil Sands Region (AOSR), Alberta, Canada were investigated as part of a long-term lichen bioindicator study. The study focused on eight elements (sulfur, nitrogen, aluminum, calcium, iron, nickel, strontium, vanadium) that were previously identified as tracers for the major oil sand production sources. Samples of the in situ epiphytic lichen Hypogymnia physodes were collected in 2002, 2004, 2008, 2011, 2014, and 2017 within a ~150?km radius from the center of surface oil sand production operations in the AOSR. Site-specific time series analysis conducted at eight jack pine upland sites that were repeatedly sampled generally showed significant trends of increasing lichen concentrations for fugitive dust linked elements, particularly at near-field (<25?km from a major oil sands production operation) sample locations. Multiple regional scale geostatistical models were developed and evaluated to characterize broad-scale changes in atmospheric deposition based on changes in H. physodes elemental concentrations between 2008 and 2014. Empirical Bayesian kriging and cokriging lichen element concentrations with oil sands mining, bitumen upgrading, coke materials handling, and limestone quarry/crushing influence variables produced spatial interpolation estimates with the lowest validation errors. Gridded zonal mean lichen element concentrations were calculated for the two comprehensive sampling years (2008, 2014) and evaluated for spatial and temporal change. Lichen sulfur concentrations significantly increased in every grid cell within the domain with the largest increases (44–88%) in the central valley in close proximity to the major surface oil sand production operations, while a minor nitrogen concentration decrease (?20%) in a single grid cell was observed. The areal extent of fugitive dust element deposition generally increased with significantly higher deposition to lichens restricted to the outer grids of the enhanced deposition field, reflecting new and expanding surface mining activity.Lara, M.J., Lin, D.H., Andresen, C., Lougheed, V.L., Tweedie, C.E., 2019. Nutrient release from permafrost thaw enhances CH4 emissions from Arctic tundra wetlands. Journal of Geophysical Research: Biogeosciences 124, 1560-1573.: High‐latitude climate change has impacted vegetation productivity, composition, and distribution across tundra ecosystems. Over the past few decades in northern Alaska, emergent macrophytes have increased in cover and density, coincident with increased air and water temperature, active layer depth, and nutrient availability. Unraveling the covarying climate and environmental controls influencing long‐term change trajectories is paramount for advancing our predictive understanding of the causes and consequences of warming in permafrost ecosystems. Within a climate‐controlled carbon flux monitoring system, we evaluate the impact of elevated nutrient availability associated with degraded permafrost (high‐treatment) and maximum field observations (low‐treatment), on aquatic macrophyte growth and methane (CH4) emissions. Nine aquatic Arctophila fulva‐dominated tundra monoliths were extracted from tundra ponds near Utqia?vik, Alaska, and placed in growth chambers that controlled ambient conditions (i.e., light, temperature, and water table), while measuring plant growth (periodically) and CH4 fluxes (continuously) for 12 weeks. Results indicate that high nutrient treatments similar to that released from permafrost thaw can increase macrophyte biomass and total CH4 emission by 54 and 64%, respectively. However, low treatments did not respond to fertilization. We estimate that permafrost thaw in tundra wetlands near Utqia?vik have the potential to enhance regional CH4 efflux by 30%. This study demonstrates the sensitivity of arctic tundra wetland biogeochemistry to nutrient release from permafrost thaw and suggests the decadal‐scale expansion of A. fulva‐dominant aquatic plant communities, and increased CH4 emissions in the region were likely in response to thawing permafrost, potentially representing a novel case study of the permafrost carbon feedback to warming.Plain Language Summary: Over the past half century near the town of Utqia?vik (formerly Barrow) Alaska, plants growing in wetlands have expanded, over the same time period as increases in air/pond temperatures, permafrost thaw, and nutrient availability. Although circumstantial evidence suggests nutrients released from permafrost thaw may have influenced past vegetation expansion and land‐atmosphere carbon exchange, direct evidence is lacking. We built a climate and environmentally controlled carbon flux monitoring system to evaluate the impact of nutrient availability on plant growth and CH4 emissions, associated with (1) permafrost thaw and (2) the maximum field‐based observations. We found nutrients released from permafrost thaw/degradation to increase emergent plant biomass and CH4 emissions by 54 and 64%, respectively. While, nutrient concentrations similar to maximum field concentrations had no effect. Assuming permafrost thaw only occurs in aquatic tundra (~9% of the land surface area), our estimates suggest that regional CH4 emissions may be enhanced by 30%. We conclude that long‐term patterns of emergent vegetation expansion and increased CH4 emissions in this region were likely due to thawing permafrost, which may represent a novel well‐documented case study of the permafrost carbon feedback to warming.Lasareva, E.V., Parfenova, A.M., Romankevich, E.A., Lobus, N.V., Drozdova, A.N., 2019. Organic matter and mineral interactions modulate flocculation across Arctic river mixing zones. Journal of Geophysical Research: Biogeosciences 124, 1651-1664. focus of this study is organic matter changes and suspended particle and colloid behavior in riverine and marine water mixing zones. Laboratory experiments demonstrated that salinity, clay mineral type, and the nature of dissolved organic matter (DOM) have a strong influence on mineral suspension stabilities (clays, carbonates, and ferric hydroxide), which represent the main fractions of particulate and colloidal matter riverine export. Clay mineral modification by humic acids stabilizes suspensions under increasing salinity, resulting in greater export of particles to coastal zones. Simultaneously, modified particles are more efficiently aggregated by a flocculant than nonmodified particles. Field investigations were conducted in Arctic river mixing zones, providing new information about colloid matter and colloid organic carbon distributions in the mixing zones, which agreed well with laboratory studies. The ratio between colloid organic carbon and suspended matter may prove a useful criterion to distinguish effective flocculation zones. Arctic River DOM fluorescence suggests dominance of terrigenous humic substances in mixing zones as well as coprecipitation by coagulation and flocculation. Our findings may reconcile reports of nonconservative behavior of DOM previously reported in the mixing zone at salinities of less than 12. We suggest that there is a flocculation mechanism in the estuarine mixing zone, which implies the presence of natural active substances, released during microorganism viral lysis (viral shunting).Lee, H.-S., Hur, J., Lee, M.-H., Brogi, S.R., Kim, T.-W., Shin, H.-S., 2019. Photochemical release of dissolved organic matter from particulate organic matter: Spectroscopic characteristics and disinfection by-product formation potential. Chemosphere 235, 586-595. this study, we investigated the photochemical release of dissolved organic matter (DOM) from the particulate organic matter (POM) of soil and litter leaves (broad leaves; coniferous leaves) and compared the releasing characteristics of the DOM using UV-visible and fluorescence spectroscopy. The disinfection by-product formation potential (DBPFP) of the released DOM was also examined. Additional dissolved organic carbon (DOC) was released by UV irradiation for all POM sources (10.58?±?2.7?mg-C L?1 g?1 for BL, 8.32?±?2.6?mg-C L?1 g?1 for CL, and 0.20?±?0.1?mg-C L?1 g?1 for soil). The excitation-emission matrix combined with parallel factor analysis results showed that the photo-released DOM from soil was mainly humic-like components (C1, C3) produced by photodesorption, resulting in high trihalomethane formation potential, while protein-like component (C2) was the major component of the photodissolved DOM from litter leaves, resulting in high haloaceticacid formation potential. Further, DBPFP from soil and litter leaves showed high correlation with humic-like components (C1+C3) and SUVA254, respectively. In conclusion, this study demonstrates that significant amounts of DOM could be released from POM under UV irradiation, although the characteristics and DBP formation of the photo-released DOM were highly dependent upon the POM source.Lee, S.-A., Kim, T.-H., Kim, G., 2019. Tracing the sources of dissolved organic carbon occurring in a coastal bay surrounded by heavily industrialized cities using stable carbon isotopes. Biogeosciences Discussions 2019, 1-25. sources of dissolved organic matter (DOM) in coastal waters are diverse, and they play different roles in biogeochemistry and ecosystems. In this study, we measured dissolved organic carbon (DOC) and nitrogen (DON), δ13C-DOC, and fluorescent dissolved organic matter (FDOM) in coastal bay waters surrounded by heavily industrialized cities (Masan Bay, Korea) to determine the different DOM sources in this region. The surface seawater samples were collected in two sampling campaigns (Aug. 2011 and Aug. 2016). The salinities ranged from 10 to 21 in 2011 and from 25.4 to 32 in 2016. In 2011, the excess DOC was observed for higher-salinity waters (16–21), indicating its main source from marine autochthonous production according to the δ13C-DOC values of ?23.7?‰ to ?20.6?‰, higher concentrations of protein-like FDOM, and lower DOC?/?DON (C?/?N) ratios. By contrast, the high DOC waters in high-salinity waters of 2016 were characterized by low FDOM, more depleted δ13C values of ?28.8?‰ to ?21.1?‰, and high C?/?N ratios, suggesting that the excess DOC is influenced by direct land-seawater interactions. Our results show that multiple DOM tracers such as δ13C-DOC, FDOM, and C?/?N ratios are powerful for discriminating the complicated sources of DOM in coastal waters.Legrand, B., Miras, Y., Beauger, A., Dussauze, M., Latour, D., 2019. Akinetes and ancient DNA reveal toxic cyanobacterial recurrences and their potential for resurrection in a 6700-year-old core from a eutrophic lake. Science of The Total Environment 687, 1369-1380. order to evaluate the recurrence of toxic cyanobacterial blooms and to determine the survival capabilities of the resistance cells through time, a sedimentary core spanning 6700?years was drilled in the eutrophic Lake Aydat. A multiproxy approach (density, magnetic susceptibility, XRF, pollen and non-pollen palynomorph analyses), was used initially to determine the sedimentation model and the land uses around the lake. Comparison with the akinete count revealed that Nostocales cyanobacteria have been present in Lake Aydat over a six thousand year period. This long-term cyanobacterial recurrence also highlights the past presence of both the anaC and mcyB genes, involved in anatoxin-a and microcystin biosynthesis, respectively, throughout the core. The first appearance of cyanobacteria seems to be linked to the natural damming of the river, while the large increase in akinete density around 1800?cal.yr BP can be correlated with the intensification of human activities (woodland clearance, crop planting, grazing, etc.) in the catchment area of the lake, and marks the beginning of a long period of eutrophication. This first investigation into the viability and germination potential of cyanobacteria over thousands of years reveals the ability of intact akinetes to undergo cell divisions even after 1800?years of sedimentation, which is 10 times longer than previously observed. This exceptional cellular resistance, coupled with the long-term eutrophic conditions of this lake, could partly explain the past and current recurrences of cyanobacterial proliferations.Lehn, I., Horodyski, R.S., Paim, P.S.G., 2019. Marine and non-marine strata preserving Ediacaran microfossils. Scientific Reports 9, 9809. report the first occurrence of microfossils in Ediacaran strata of the Camaqu? Basin. The assemblage includes simple (Leiosphaeridia sp. predominantly) and ornamented acritarchs associated with microbial mats. They are related to the Ediacaran Complex Acanthomorph Palynoflora (ECAP) and Late Ediacaran Leiosphere Palynoflora (LELP) due to the similar morphology and time interval assigned to those assemblages, though the observed specimens are a lot simpler and less diversified. However, different from the usual occurrences, this case study reports Neoproterozoic cosmopolitan communities living in marine (basal unit) and lacustrine (middle units) settings. Fossils within non-marine strata in the Precambrian record are rare. Therefore, this first finding of microfossils in the Camaqu? Basin constitutes a new piece of the puzzle related to the history of the Panafrican-Brasiliano basins and shed some light on possible settings where the Ediacaran eukaryotes have evolved.Lehrmann, D.J., Yang, W., Sickmann, Z.T., Ferrill, D.A., McGinnis, R.N., Morris, A.P., Smart, K.J., Gulliver, K.D.H., 2019. Controls on sedimentation and cyclicity of the Boquillas and equivalent Eagle Ford Formation from detailed outcrop studies of western and central Texas, U.S.A. Journal of Sedimentary Research 89, 629-653. of the Boquillas and equivalent Eagle Ford Formation can be assigned to two associations: a hydrodynamically recycled association and a pelagic association. The hydrodynamically recycled association is composed of lenticular to continuous cross-laminated lime packstone–grainstone, heterolithic facies, and intraclastic grainstone conglomerate with intercalated calcareous mudrock. Sharp bedding contacts, abundant scours, ripple cross-lamination, oscillatory-current indicators, hummocky cross-bedding, and rounded clasts indicate recycling of the bottom sediments by storms and bottom currents above storm wave base (SWB). The pelagic association is composed of continuous lime packstone to grainstone and chalk beds with intercalated calcareous mudrock. Gradational contacts and planar lamination indicate dominant deposition by pelagic rain, but scour surfaces, coarse-fine alternations, and ripple cross-laminae indicate the influence of bottom currents below SWB.Vertical shifts between the hydrodynamically recycled association, interpreted to represent storm agitation of the seafloor during falls in sea level, alternate with the pelagic association and define four sequence boundaries and three depositional sequences with a lower-order periodicity (third-order periodicity, ca. average 2.4 My). Sequence boundaries correspond approximately to member boundaries recognized by gamma-ray profiles. Spectral analysis reveals higher-frequency mudrock–carbonate cycles prominent in the pelagic association, likely resulting from Milankovitch climate forcing of planktonic carbonate productivity versus clay flux. Comparison of gamma-corrected spectra with absolute age constraints reveals that the Ernst Tinaja section (in Big Bend National Park) is less than 28% complete. This is interpreted to result from abundant depositional hiatuses and erosional gaps that occur at the bed scale and at member boundaries within and bounding the Eagle Ford Formation.We demonstrate that deep-marine pelagic deposits in epicratonic settings may be subject to a complex interaction of depositional processes including pelagic rain and recycling by bottom currents and wave-generated currents modulated by low-frequency sea-level fluctuation and high-frequency fluctuations in sediment supply.Lei, Z., Xu, H., Liu, Q., Li, W., Yan, D., Li, S., Lei, P., Yan, M., Li, J., 2019. The influence of multiple-stage oil emplacement on deeply buried marine sandstone diagenesis: A case study on the Devonian Donghe sandstones, Tabei Uplift, Tarim Basin, NW China. Marine and Petroleum Geology 110, 299-316. the oil emplacement influence on diagenesis is one of the most key factors of reservoir quality prediction. The Devonian Donghe sandstones are deeply buried to 5700～6000?m, and they are important exploration target in the Tarim Basin, additional the reservoirs experienced multi-phase hydrocarbon accumulation and destruction. The Donghe sandstones contain various diagenetic minerals, which are mainly composed of calcite cement, a small amount of quartz overgrowth and pyrite, trace ankerite and ferrocalctie. The current study investigates the influence of multiple-stage oil emplacement on the diagenesis with particular attention to calcite and quartz cementation of marine clastic reservoir interval of the Donghe sandstones in the Tarim Basin.The samples in the oil leg and water leg have been collected and a series of studies were performed, including thin section petrography, scanning electron microscopy (SEM), carbon and oxygen isotopes and cathodoluminescence (CL) analysis. The δ13CV-PDB values of calcite cement from the oil leg and water leg between ?4.73 and ?1.21‰ and ?3.81 to ?0.86‰, respectively. The δ18OV-PDB values of calcite cement from the oil leg and water leg range from ?15.59 to ?6.61‰ and ?14.97 to ?7.76‰, respectively. Both of them display no obviously different in the oil leg and water leg. All of the δ13CV-PDB values in the whole interval of the Donghe sandstones show lightly depletion was explained mixing from marine carbon and carbon produced from bacterial sulfate reduction (BSR) that happens during petroleum degradation associated with sulfate reduced by hydrocarbons bacterially. Two dull-luminescence zones, trace Fe and Mn content, and high Fe accompanied by low Mn content, and orange-red- and bright-orange-yellow-luminescence zones in oil leg indicate four generations of calcite occurred, whereas two generations of calcite occurs in water leg, which are dull- and orange-red-luminescence zones.Two origins of calcite cement were clearly identified: marine biogenic carbonates and hydrocarbon-related from palaeo-reservoir BSR during uplift. The first generation of calcite cement originated from biogenic carbonate, the second and third generations of calcite cement were mixing from predate carbonate cement dissolved and re-precipitated, and calcite precipitated by BSR directly. Some quartz grains and K-feldspars were dissolved by residual organic acids that remained in the irreducible water, and following replaced by the fourth generation of calcite cement. Some calcite cement in the oil leg precipitated in a temperature higher than the homogeneous temperature of fluid inclusion, which indicates oil emplacement has no influence on calcite cementation. The quartz overgrowth postdate the first hydrocarbon accumulation and predate the second hydrocarbon accumulation, which originated from quartz grains dissolved by organic acids that produced from BSR and re-precipitated at a low temperature (<80?°C). The pyrite cement formed as the by-product of BSR in the water leg implies the palaeo-reservoir existed.The current study can promote the understanding of the influence of multiple-stage hydrocarbon accumulation on diagenesis, and it can also inspire the diagenesis process of other Paleozoic hydrocarbon reservoirs in the Tarim Basin.Letourneau, M.L., Medeiros, P.M., 2019. Dissolved organic matter composition in a marsh-dominated estuary: Response to seasonal forcing and to the passage of a hurricane. Journal of Geophysical Research: Biogeosciences 124, 1545-1559.: Dissolved organic matter (DOM) is a large and complex mixture of compounds with source inputs that differ with location, season, and environmental conditions. Here, we investigated drivers of DOM composition changes in a marsh‐dominated estuary off the southeastern United States. Monthly water samples were collected at a riverine and estuarine site from September 2015 to September 2016, and bulk, optical, and molecular analyses were conducted on samples before and after dark incubations. Results showed that river discharge was the primary driver changing the DOM composition at the mouth of the Altamaha River. For discharge higher than ~150 m3/s, dissolved organic carbon (DOC) concentrations and the terrigenous character of the DOM increased approximately linearly with river flow. For low discharge conditions, a clear signature of salt marsh‐derived compounds was observed in the river. At the head of Sapelo Sound, changes in DOM composition were primarily driven by river discharge and possibly by summer algae blooms. Microbial consumption of DOC was larger during periods of high discharge at both sites, potentially due to the higher mobilization and influx of fresh material to the system. The Georgia coast was hit by Hurricane Matthew in October 2016, which resulted in a large input of carbon to the estuary. The DOC concentration was ~2 times higher and DOM composition was more aromatic with a stronger terrigenous signature compared to the seasonal maximum observed earlier in the year during peak river discharge conditions. This suggests that extreme events notably impact DOM quantity and quality in estuarine regions.Plain Language Summary: Dissolved organic matter (DOM) is a crucial component of aquatic ecosystems and characterizing how its composition and concentration change is important to better understand the carbon cycle. Composition and quantity of DOM can vary spatially and temporally due to a variety of factors, including biological activity, precipitation patterns, and proximity to source inputs such as rivers, salt marshes, and the open ocean. To track these changes, monthly water samples were collected and analyzed over the course of a year in a marsh‐dominated estuary off the Georgia coast, USA. River flow was shown to be an important factor controlling the amount and type of DOM present at both riverine (Altamaha River) and estuarine (Sapelo Sound) locations. In months with high river flow, organic matter contents were higher and had more terrestrially derived compounds compared to months with low river flow. Additionally, Hurricane Matthew was shown to significantly alter the organic matter at Sapelo Sound, suggesting that extreme events greatly impact DOM quantity and quality in estuarine regions.Levin, S.R., Scott, T.W., Cooper, H.S., West, S.A., 2019. Darwin's aliens. International Journal of Astrobiology 18, 1-9. predictions about aliens is not an easy task. Most previous work has focused on extrapolating from empirical observations and mechanistic understanding of physics, chemistry and biology. Another approach is to utilize theory to make predictions that are not tied to details of Earth. Here we show how evolutionary theory can be used to make predictions about aliens. We argue that aliens will undergo natural selection – something that should not be taken for granted but that rests on firm theoretical grounds. Given aliens undergo natural selection we can say something about their evolution. In particular, we can say something about how complexity will arise in space. Complexity has increased on the Earth as a result of a handful of events, known as the major transitions in individuality. Major transitions occur when groups of individuals come together to form a new higher level of the individual, such as when single-celled organisms evolved into multicellular organisms. Both theory and empirical data suggest that extreme conditions are required for major transitions to occur. We suggest that major transitions are likely to be the route to complexity on other planets, and that we should expect them to have been favoured by similarly restrictive conditions. Thus, we can make specific predictions about the biological makeup of complex aliens.Li, C., Kong, L., Ostadhassan, M., Gentzis, T., 2019. Nanoscale pore structure characterization of tight oil formation: A case study of the Bakken Formation. Energy & Fuels 33, 6008-6019. structure of unconventional reservoir is fundamental for understanding hydrocarbon storage, fluid transport, and geomechanics. The pore structure of shale gas reservoirs has been studied extensively, while investigation regarding the pore structure of shale oil reservoirs remains limited. The Bakken formation is one of the largest contributors to the growth of unconventional oil in the U.S. In this study, 13 core samples collected from the Bakken formation were examined through a series of experiments to investigate the geochemical properties and mineralogy, especially pore structure. Mineralogy analysis through the X-ray diffraction (XRD) test showed that quartz and illite are the major components for the upper and lower shale members, while quartz, feldspar, and dolomite dominate the middle member of the Bakken formation. Rock-Eval source rock analysis illustrated that all of the shale samples contain a significant percentage of organic matter. Nitrogen and carbon dioxide adsorption results showed that isotherm curves obtained from nitrogen adsorption are reserved S-shaped (typical type II curve), indicating that pores are mainly micro- and mesopores. Linear regression analysis of pore structure parameters with respect to total organic carbon (TOC) and mineral composition reveals that the TOC content has a positive relationship with micropore volume, while meso- and macropores are controlled by clay content. Development of micropores in organic matter is thermal-maturity-related. Shale samples with vitrinite reflectance higher than 1.0% have a higher surface area, suggesting that more micropores were developed in the organic matter after maturities of shales reached oil window level. In addition, results of the fractal analysis showed that samples with higher fractal dimension values are featured by more micropore volume, smaller pore diameter, and larger specific surface area.Li, G., Qin, Y., Wu, M., Zhang, B., Wu, X., Tong, G., Liu, J., 2019. The pore structure of the transitional shale in the Taiyuan formation, Linxing area, Ordos Basin. Journal of Petroleum Science and Engineering 181, 106183. in-depth study of the pore structure and its controlling factors of shale reservoir has important guiding significance for further exploration and exploitation of shale gas. Therefore, 10 transitional shale samples were collected from the Taiyuan formation in the Linxing area, Ordos Basin, and experiments on geochemical constitution, low-temperature gas adsorption were carried out. Based on the experimental results, the material composition, pore features and its controlling factors of the transitional shale were analyzed. The results show that the total organic carbon (TOC) content of the transitional shale in the Linxing area ranges from 0.73% to 10.20%, and the thermal evolution of organic matter (OM) is in a stage of mature to highly mature. In addition to small quantities of feldspar, siderite and pyrite, the two main components of this shale are 52–71% of clay minerals and 24–45% of quartz. The clay minerals are composed of kaolinite, accounting for 23%–74% of the total clay minerals, followed by an illite mixed layer, illite and chlorite. Mesopores are the major contributor to pore volume (PV), while macropores contribute the least to the PV. The contribution of micropores to the specific surface area (SSA) is greater than 78%, followed by mesopores. Macropores have almost no contribution to the development of the SSA. The OM types, hydrocarbon expulsion intensity control the influence of TOC content on pores development. The total amount of clay minerals is beneficial to the development of PV and SSA, which is mainly attributed by chlorite and illite mixed layer. Compared with the marine shale, the brittle minerals inhibit the development of pores in the transitional shale.Li, J., Lu, S., Jiang, C., Wang, M., Chen, Z., Chen, G., Li, J., Lu, S., 2019. Characterization of shale pore size distribution by NMR considering the influence of shale skeleton signals. Energy & Fuels 33, 6361-6372. a non-destructive method, the proton nuclear magnetic resonance (1H NMR) technique with low echo time (TE, e.g., 0.07 ms) has been increasingly used for characterizing full pore size distribution (PSD) of shales. However, hydrogen contained in some components of the shale skeleton (e.g., kerogen and structural water) also can be detected by NMR in the case of low TE, resulting in a questionable PSD derived directly from the T2 spectra of oil-saturated shale. In this study, eight shale samples with different organic and mineralogical components from the Jiyang Depression, China were investigated with regular NMR, low-temperature nitrogen adsorption (LTNA), NMR cryoporometry (NMRC), and mercury injection capillary pressure (MICP) techniques to propose a corrected NMR approach for characterizing shale PSD by considering the influence of the shale skeleton signals. The NMR relaxation characteristics (e.g., T2 spectra and T1–T2 map) of as-received shale, solvent-extracted and dried shale (EX), and oil-saturated shale (OS) were discussed to reveal the NMR response from the shale skeleton itself at T2 below 1 ms on the T2 spectra. With the new approach, the NMR T2 spectra of oil occurring in the OS shale were first obtained through inversion of the differentiated T2 decay curves between the T2 decay curves of the EX shale and OS shale and were then converted to PSD by combination of LTNA, NMRC, and MICP results. For pores with T2 less than 1 ms, the PSD obtained from NMR T2 spectra of the oil signals only compared well with the results of LTNA and NMRC, with a relative error of less than 15% in pore volume. In contrast, the relative errors of PSD obtained directly from the NMR T2 spectra of oil-saturated shales were up to 134%. It was found that the higher total organic carbon shale contained, the larger errors in the PSD profiles, pore volume, and porosity that were calculated directly from the oil-saturated shale’s NMR T2 spectra. Compared with the traditional NMR methods, the corrected approach can provide a more accurate PSD for shales, especially for those organic-rich ones.Li, J., Luo, C., Zhang, D., Cai, X., Jiang, L., Zhang, G., 2019. Stable-isotope probing-enabled cultivation of the indigenous bacterium Ralstonia sp. strain m1, capable of degrading phenanthrene and biphenyl in industrial wastewater. Applied and Environmental Microbiology 85, e00511-19.: To identify and obtain the indigenous degraders metabolizing phenanthrene (PHE) and biphenyl (BP) from the complex microbial community within industrial wastewater, DNA-based stable-isotope probing (DNA-SIP) and cultivation-based methods were applied in the present study. DNA-SIP results showed that two bacterial taxa (Vogesella and Alicyclobacillus) were considered the key biodegraders responsible for PHE biodegradation only, whereas Bacillus and Cupriavidus were involved in BP degradation. Vogesella and Alicyclobacillus have not been linked with PHE degradation previously. Additionally, DNA-SIP helped reveal the taxonomic identity of Ralstonia-like degraders involved in both PHE and BP degradation. To target the separation of functional Ralstonia-like degraders from the wastewater, we modified the traditional cultivation medium and culture conditions. Finally, an indigenous PHE- and BP-degrading strain, Ralstonia pickettii M1, was isolated via a cultivation-dependent method, and its role in PHE and BP degradation was confirmed by enrichment of the 16S rRNA gene and distinctive dioxygenase genes in the DNA-SIP experiment. Our study has successfully established a program for the application of DNA-SIP in the isolation of the active functional degraders from an environment. It also deepens our insight into the diversity of indigenous PHE- and BP-degrading communities.Importance: The comprehensive treatment of wastewater in industrial parks suffers from the presence of multiple persistent organic pollutants (POPs), such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), which reduce the activity of activated sludge and are difficult to eliminate. Characterizing and applying active bacterial degraders metabolizing multiple POPs therefore helps to reveal the mechanisms of synergistic metabolism and to improve wastewater treatment efficiency in industrial parks. To date, SIP studies have successfully investigated the biodegradation of PAHs or PCBs in real-world habitats. DNA-SIP facilitates the isolation of target microorganisms that pose environmental concerns. Here, an indigenous phenanthrene (PHE)- and biphenyl (BP)-degrading strain in wastewater, Ralstonia pickettii M1, was isolated via a cultivation-dependent method, and its role in PHE and BP degradation was confirmed by DNA-SIP. Our study provides a routine protocol for the application of DNA-SIP in the isolation of the active functional degraders from an environment.Li, J., Zhang, H., Liu, P., Menguy, N., Roberts, A.P., Chen, H., Wang, Y., Pan, Y., 2019. Phylogenetic and structural identification of a novel magnetotactic Deltaproteobacteria strain, WYHR-1, from a freshwater lake. Applied and Environmental Microbiology 85, e00731-19.: Magnetotactic bacteria (MTB) are phylogenetically diverse prokaryotes that are able to biomineralize intracellular, magnetic chains of magnetite or greigite nanocrystals called magnetosomes. Simultaneous characterization of MTB phylogeny and biomineralization is crucial but challenging because most MTB are extremely difficult to culture. We identify a large rod, bean-like MTB (tentatively named WYHR-1) from freshwater sediments of Weiyang Lake, Xi’an, China, using a coupled fluorescence and scanning electron microscopy approach at the single-cell scale. Phylogenetic analysis of 16S rRNA gene sequences indicates that WYHR-1 is a novel genus from the Deltaproteobacteria class. Transmission electron microscope observations reveal that WYHR-1 cells contain tens of magnetite magnetosomes that are organized into a single chain bundle along the cell long axis. Mature WYHR-1 magnetosomes are bullet-shaped, straight, and elongated along the [001] direction, with a large flat end terminated by a {100} face at the base and a conical top. This crystal morphology is distinctively different from bullet-shaped magnetosomes produced by other MTB in the Deltaproteobacteria class and the Nitrospirae phylum. This indicates that WYHR-1 may have a different crystal growth process and mechanism from other species, which results from species-specific magnetosome biomineralization in MTB.Importance: Magnetotactic bacteria (MTB) represent a model system for understanding biomineralization and are also studied intensively in biogeomagnetic and paleomagnetic research. However, many uncultured MTB strains have not been identified phylogenetically or investigated structurally at the single-cell level, which limits comprehensive understanding of MTB diversity and their role in biomineralization. We have identified a novel MTB strain, WYHR-1, from a freshwater lake using a coupled fluorescence and scanning electron microscopy approach at the single-cell scale. Our analyses further indicate that strain WYHR-1 represents a novel genus from the Deltaproteobacteria class. In contrast to bullet-shaped magnetosomes produced by other MTB in the Deltaproteobacteria class and the Nitrospirae phylum, WYHR-1 magnetosomes are bullet-shaped, straight, and highly elongated along the [001] direction, are terminated by a large {100} face at their base, and have a conical top. Our findings imply that, consistent with phylogenetic diversity of MTB, bullet-shaped magnetosomes have diverse crystal habits and growth patterns.Li, J., Zhao, J., Wei, X., Chen, M., Song, P., Han, Z., Wu, W., 2019. Origin of abnormal pressure in the Upper Paleozoic shale of the Ordos Basin, China. Marine and Petroleum Geology 110, 162-177. in the Upper Paleozoic shale of the Ordos Basin (UPSOB) in China occurred mainly in the Early Cretaceous, and is modeled using the PetroMod simulation method in this paper. The origin of paleo-overpressure was analyzed based on the multiple-logging combination method, Bowers' method, and the velocity–density cross-plot method using logging data and shale porosity. The causes of the underpressure and normal pressure, and the history of their evolution were investigated based on a large amount of drilling and pressure data for the basin. The results indicate that paleo-overpressure in the UPSOB produced in the Early Cretaceous was not the cause of disequilibrium compaction, but this occurred owing to increased hydrocarbon generation. Since the Late Cretaceous, during the overall uplift of the Ordos Basin, the decrease in temperature has led to a reduction in pore pressure of 23.93–34.35?MPa, accounting for 56.69%–69.47% of total pressure loss. A combination of the expansion and diffusion of natural gas has led to a decrease in pore pressure of 9.52–22.60?MPa, accounting for 27.63%–41.83% of total pressure loss. The effects of pore rebound on pressure loss were weak. Therefore, temperature decrease alone could not have led to the current underpressure and normal pressure, and the expulsion of gas owing to tectonic uplifting might have been the most important factor. The UPSOB likely had a relatively high gas expulsion efficiency, especially during late-stage tectonic uplifting, which may be a major risk for shale gas exploration.Li, M., Vogt, S.J., May, E.F., Johns, M.L., 2019. In situ CH4–CO2 dispersion measurements in rock cores. Transport in Porous Media 129, 75-92. of carbon dioxide (CO2) into a natural gas reservoir is an emerging technology for enhanced natural gas recovery (EGR) realizing increased natural gas production whilst sequestering the injected CO2. However, given that CO2 and natural gas are completely miscible, simulation of potential EGR scenarios is required to determine when breakthrough of CO2 will occur at the natural gas production wells. For such reservoir simulations to be reliable (independent of software used), accurate dispersion data between CO2 and natural gas at relevant reservoir conditions are required. To this end, we apply one-dimensional magnetic resonance imaging (MRI) to quantify this dispersion process in situ in both sandstone and carbonate rock cores. Specifically we apply the SPRITE MRI sequence (Balcom et al. in J Magn Reson Ser A 123(1):131–134, 1996. ) to facilitate quantitative axial profiles of methane (CH4) content during core flooding processes between CO2 and CH4. Simultaneously we measure, using infrared, the effluent CO2 and CH4 concentrations enabling ex situ dispersion measurements. Via comparison with the corresponding MRI data, the erroneous contributions to dispersion from entry/exit effects and mixing in piping to and from the rock core holder are quantified. Furthermore, we demonstrate how nuclear magnetic resonance T2 measurements can be uniquely used to probe the pore size occupancy of the CH4 during the core flooding process.Li, S., Liu, L., Chai, P., Li, X., He, J., Zhang, Z., Wei, L., 2019. Imaging hydraulic fractures of shale cores using combined positron emission tomography and computed tomography (PET-CT) imaging technique. Journal of Petroleum Science and Engineering 182, 106283. Computed Tomography (CT) method is an integral part of hydraulic-fracture imaging, but its application to micro-fractures in cores is limited. This paper documents the visualization of fractured cores via an accessorial PET-CT approach to improve both spatial resolution and image contrast. PET-CT approach combines X-ray Computed Tomography (CT) and positron emission tomography (PET) method. CT technique provides information of core structure and accurate location of fractures based on density variations. PET is a nuclear imaging technique through inducing radionuclide into fractures, offering the potential to overcome CT limitations by providing information of micro-fractures. Combined PET-CT approach has been demonstrated as a technical advancement for imaging fractured cores better than simply CT or PET method. Comprehensive information of core structure, micro-fractures and connected fractures could be provided by PET-CT method. The applicability of each visualization technique was evaluated, the favorable implementation of combined PET-CT for laboratory core analysis was discussed.Li, X., Chen, S., Wang, X., Zhu, Y., Chang, M., Uwamahoro, C., 2019. Pore structure heterogeneity of the Xiamaling Formation shale gas reservoir in the Yanshan Area of China: Evaluation of geological controlling factors. Acta Geologica Sinica - English Edition 93, 588-603. is an integral parameter of the pore structure of shale gas reservoir and it forms an essential basis for setting and adjusting development parameters. In this study, scanning electron microscopy, high-pressure mercury intrusion and low-temperature nitrogen adsorption experiments were used to qualitatively and quantitatively characterize the pore structure of black shale from the third member of the Xiamaling Formation in the Yanshan area. The pore heterogeneity was studied using fractal theory, and the controlling factors of pore development and heterogeneity were evaluated in combination with geochemical parameters, mineral composition, and geological evolution history. The results show that the pore structure of the reservoir was intricate and complicated. Moreover, various types of micro-nano scale pores such as dissolution pores, intergranular pores, interlayer pores, and micro-cracks are well developed in member 3 of the Xiamaling Formation. The average porosity was found to be 6.30%, and the mean value of the average pore size was 4.78 nm. Micropores and transition pores provided most of the storage space. Pore development was significantly affected by the region and was mainly related to the total organic carbon content, vitrinite reflectance and mineral composition. The fractal dimension, which characterizes the heterogeneity, is 2.66 on average, indicating that the pore structure is highly heterogeneous. Fractal dimension is positively correlated with maturity and clay mineral content, while it is negatively correlated with brittle mineral content and average pore size. These results indicate that pore heterogeneity is closely related to thermal history and material composition. Combined with the geological background of this area, it was found that the pore heterogeneity was mainly controlled by the Jurassic magmatism. The more intense the magma intrusion, the stronger the pore heterogeneity. The pore structure and its heterogeneity characteristics present today are a general reflection of the superimposed geological processes of sedimentary-diagenetic-late transformation. The influence of magmatic intrusion on the reservoir is the main geological factor that should be considered for detailed evaluation of the Xiamaling Formation shale gas reservoir in the Yanshan area.Li, X., Chi, P., Guo, X., Sun, Q., 2019. Effects of asphaltene concentration and asphaltene agglomeration on viscosity. Fuel 255, 115825. are regarded as the most polar and heaviest components in crude oil system. Their precipitation and agglomeration cause problems in oil recovery, production, and transportation. Asphaltenes are directly responsible for determining the viscosity of crude oil. In this work, the effects of asphaltene concentration and asphaltene agglomeration on viscosity were investigated. Toluene and heptane were used as asphaltene solvent and precipitant. The viscosities of asphaltenes-toluene solutions with various asphaltene concentrations were measured to investigate the impact of asphaltene concentration on viscosity. The results indicate that the viscosity of asphaltene-toluene solution exponentially increases with the asphaltene concentration. Elevated temperature causes viscosity reduction. The effect of temperature on viscosity reduction is more significant at higher asphaltene concentration. The dependence of viscosity on temperature can be well described by the Arrhenius equation, by considering the significance of activation energy. On the other hand, the asphaltene agglomerates form and grow with the increase of heptane concentration in crude oil-heptane-toluene mixture. A sharp viscosity rise of crude oil-heptane-toluene mixture was observed beyond heptane threshold concentration of 60?vol%. This is mainly resulted from the significant formation and growth of asphaltene agglomerates in asphaltene suspensions. The interactions between micro-sized asphaltene agglomerate particles could significantly affect the viscosity of liquid–solid system. The particle properties of asphaltene agglomerates including size, size distribution, number and shape factor were analyzed by microscopic images of the synthetic diluted oil. These contribute to the understanding of the effect of particle properties of asphaltene agglomerates on the viscosity of oil suspension.Li, X., Li, C., Bai, Y., Shi, X., Su, R., 2019. Composition variations and spatiotemporal dynamics of dissolved organic matters during the occurrence of green tide (Ulva prolifera blooms) in the Southern Yellow Sea, China. Marine Pollution Bulletin 146, 619-630. samples were collected from April 6 to September 6, 2017 in the Southern Yellow Sea, China where green tides often occurred, and analyzed for nutrients, dissolved organic carbon (DOC), and fluorescent dissolved organic matter (FDOM). The DOC concentrations increased significantly in the green tide areas by approximately 1.2 times compared to those in the non-green tide areas. From the large-scale outbreak to the complete dissipation of the green tide, the fluorescence intensities of the four FDOM fluorescent components identified in the green tide areas were significantly higher than those in the non-green tide areas. During the extinction period, the fluorescence intensities of the three humus-like components and one protein-like component were approximately 1.8 and 1.3 times higher than those in the non-green tide areas, respectively. These findings suggested that the outbreak of green tide could release DOM into water and affect the biogeochemical cycle in green tide regions.Li, X., Liu, W., Xu, L., 2019. Evaluation of lacustrine organic δ13C as a lake-level indicator: A case study of Lake Qinghai and the satellite lakes on the Tibetan Plateau. Palaeogeography, Palaeoclimatology, Palaeoecology 532, 109274. recent years, the sedimentary δ13Corg values have been recognized to be indicative of lake-level changes in lakes on the Tibetan Plateau (TP). However, the sensitivity of sedimentary δ13Corg to lake-level changes and the potential relationship between lake-level variations and climatic forces are still unknown in this particular region. Here, we systematically evaluate sedimentary δ13Corg as a proxy of lake-level changes in lakes with different sizes on the TP. Consistent with previous studies, the total organic matter of sediments was mainly contributed by aquatic plants in lakes on the TP. In the studied lakes, sedimentary δ13C values mainly reflect lake-level changes, as the species of aquatic plants with different δ13Corg values strongly respond to lake level. However, sedimentary δ13C values are much more sensitive to lake-level changes in a moderate-depth lake (~ 10?m) than those in a deep lake (~ 27?m) or a shallow lake (<3–5?m). In other words, the sedimentary δ13Corg may not effectively record lake-level changes on the TP when the lakes are deep (not sensitive) or shallow (only submerged plants). This relationship can be clearly seen in the case study in cores HY15 and GH02. The sedimentary δ13Corg trend in core HY15 was well correlated with the observed lake-level changes over the past 50?yr in Lake Qinghai. Based on the hypothesis that δ13Corg is indicative of lake-level changes, the lake-level change showed obvious millennial-scale oscillations in Lake Gahai (moderate lake) during the Holocene, but there were no obvious lake-level oscillations in Lake Qinghai (deep lake). In addition, the variation in the TOC/ON ratio suggested that sedimentary δ13Corg was often influenced by the contribution of terrestrial plants in Lake Gahai during the Holocene. Therefore, although δ13Corg was a very sensitive proxy of lake-level changes in lakes with maximum water depths ranging from 5?m to 20?m in lakes on the northeastern TP, we should consider the possible contribution of terrestrial plants when the sedimentary δ13Corg value is used as indicator of lake-level changes.Li, Y., Chen, S., Wang, Y., Qiu, W., Su, K., He, Q., Xiao, Z., 2019. The origin and source of the Devonian natural gas in the Northwestern Sichuan Basin, SW China. Journal of Petroleum Science and Engineering 181, 106259. gas flows have recently been discovered from the Guanwushan Formation (D2g) in the Northwestern Sichuan Basin for the first time, thus ushering in the prelude of Devonian natural gas exploration in the Sichuan Basin. However, the source and origin of the Devonian natural gas is not clear and this seriously restricts the next exploration and development stages. Based on geochemical experimental analyses, this study aimed to comprehensively research the geochemical characteristics of the Devonian natural gas, reservoir solid bitumen, and source rocks. The results showed that (1) the Devonian natural gas is mainly composed of hydrocarbon gas and is oil cracking gas. (2) The Devonian natural gas has relatively light ethane carbon isotopes ranging from ?31.82‰ and ?29.93‰, between the Cambrian and Permian natural gas values, indicating it is a mixed gas, but is more similar to the Cambrian natural gas. (3) The carbon isotopes of the Devonian reservoir solid bitumen were less than ?29‰ and C29 sterane had an absolute predominance among the sterane compounds, thus showing that it is derived from the source rocks of the Qiongzhusi Formation. (4) During the late Permian, the Lower Cambrian source rocks entered the high peak period of hydrocarbon generation and the crude oil migrated down the fractures to the Devonian reservoirs. During the later stage of deep burial, the crude oil cracked into the dry gas and the heavy contents formed pyrobitumen through polycondensation. Meanwhile, gas from the Permian source rocks mixed to form the present Devonian reservoirs. These research results play an important guiding role in the natural gas exploration and development in the marine stratum of the ultra-deep Devonian System in the Sichuan Basin.Li, Y., Gao, Y., Zhang, W., Wang, C., Wang, P., Niu, L., Wu, H., 2019. Homogeneous selection dominates the microbial community assembly in the sediment of the Three Gorges Reservoir. Science of The Total Environment 690, 50-60. reservoir sediment is a unique habitat sheltering indispensable microorganisms and facilitating their biogeochemical functions; however, the assembly processes of the microbial community therein remain elusive. This study focuses on the assembly processes in the Three Gorges Reservoir Area (TGRA). A total of 42 sediment samples were collected from the TGRA, both in the mainstream and the tributaries, and in different seasons. Metagenomic analyses of 16S rRNA using Exact Sequence Variants revealed the spatiotemporal distribution patterns of the microbial communities. Linear regressions between dissimilarity of microbial communities, geographic and environmental distance showed that environmental, rather than geographic factors, impacted the microbial community. However, the environmental differences explained little variations (14.14%) in community structure, implying the homogeneity of environmental conditions across the TGRA. From the quantification of ecological processes, homogeneous selection was shown to be a dominating factor (51.34%) in the assembly of the microbial communities. The co-occurrence network showed that keystone species were more important than prevalent abundant species in interspecies interactions. Overall, the assembly of microbial community in the deep-water reservoir sediment is mediated by both deterministic and stochastic processes, and homogeneous selection plays a leading role.Li, Y., Shi, W., Tang, S., 2019. Microbial geochemical characteristics of the coalbed methane in the Shizhuangnan Block of Qinshui Basin, North China and their geological implications. Acta Geologica Sinica - English Edition 93, 660-674. and sulfate reducing bacteria were detected by the 16SrRNA sequencing of coalbed methane (CBM) co‐produced water in the south of the Qinshui Basin, which is indicative of the presence of secondary biological gas in the south of this basin, in contradiction to the previous understanding of thermogenic gas. This work systematically collected water samples from the CBM wells in the Shizhuangnan Block and analyzed the microbial geochemical characteristics from the aspects of water ions, hydrogen and oxygen isotopes, dissolved inorganic carbon and microbial diversity. It is shown that the Shizhuangnan Block has a nearly SN‐trending monoclinic structure, and the elevation of coal seam decreases gradually from the east to west. Because of the water blocking effect of Sitou fault in the west, the precipitation flowed from the east to west, and gradually transited to stagnant flow area. The concentration variation of some ions such as Na+, K+, Ca2+, Mg2+, Cl–, HCO3– and total dissolved solids (TDS) suggest the variation of redox condition in the coal reservoir water. The 16SrDNA sequencing analysis of the collected water samples detected the presence of methanogens and sulfate reduction bacteria. The presence of methane production zone and sulfate methane transition zone (SMTZ) was identified. The effect of methanogens in the methane production zone leads to an increase in the methane concentration, resulting in a high gas content in the study area. In the SMTZ, most methane is consumed by anaerobic oxidation due to high sulfate concentrations.Li, Y., Song, G., Massicotte, P., Yang, F., Li, R., Xie, H., 2019. Distribution, seasonality, and fluxes of dissolved organic matter in the Pearl River (Zhujiang) estuary, China. Biogeosciences 16, 2751-2770. organic carbon (DOC) concentration in the Pearl River estuary (PRE) of China was measured in May, August, and October 2015 and January 2016. Chromophoric and fluorescent dissolved organic matter (CDOM and FDOM) in the latter three seasons were characterized by absorption and fluorescence spectroscopy. CDOM and FDOM exhibited negligible seasonal variations, while DOC displayed a significant seasonality, with the average concentration being highest in May (156??mol?L?1), lowest in November (87??mol?L?1), and comparable between January (118??mol?L?1) and August (112??mol?L?1). Although DOC, CDOM, and FDOM in surface water were generally higher than in bottom water, the difference between the two layers was statistically insignificant. DOC showed little cross-estuary variations in all seasons, while CDOM and FDOM in January were higher on the west side of the estuary than on the east side. All three variables showed rapid drawdowns in the head region of the estuary (salinity <5); their dynamics in the main estuary were primarily controlled by conservative mixing, leading to linearly declining or relatively constant (for DOC in May and November only) contents with increasing salinity. The decrease in FDOM with salinity was 5?%–35?% faster than that of CDOM, which in turn was 2–3 times quicker than that of DOC. Salinity and CDOM absorption coefficients could serve as indicators of DOC in August and January. Freshwater endmembers in all seasons mainly contained fresh, protein-rich DOM of microbial origin, a large part of it likely being pollution-derived. Protein-like materials were preferentially consumed in the head region but the dominance of the protein signature was maintained throughout the estuary. Exports of DOC and CDOM (in terms of the absorption coefficient at 330?nm) into the South China Sea were estimated as 195×109?g and 266×109?m2 for the PRE and 362×109?g and 493×109?m2 for the entire Pearl River Delta. The PRE presents the lowest concentrations and export fluxes of DOC and CDOM among the world's major estuaries. DOM delivered from the PRE is, however, protein-rich and thus may enhance heterotrophs in the adjacent coastal waters. Overall, the PRE manifests lower abundance and smaller spatiotemporal variability of DOM than expected for a sizable estuary with a marked seasonality of river runoff due supposedly to the poorly forested watershed of the Pearl River, the rapid degradation of the pollution-derived DOM in the upper reach, and the short residence time of freshwater.Li, Y., Wang, Z., Wu, P., Gao, X., Yu, Z., Yu, Y., Yang, J., 2019. Organic geochemistry of Upper Paleozoic source rocks in the eastern margin of the Ordos Basin, China: Input and hydrocarbon generation potential. Journal of Petroleum Science and Engineering 181, 106202. the present research, the hydrocarbon source rock potential, thermal maturity (Tmax), and paleoenvironment of Upper Paleozoic coaly source rocks of the eastern margin of the Ordos Basin, China, were assessed by using Rock-Eval pyrolysis, gas chromatography (GC), and gas chromatography–mass spectrometry (GC–MS). The tested samples were found to be composed mostly of Type III kerogen organic matter with relatively low hydrogen and low oxygen index values. Graphs of the total organic carbon (TOC) content against free hydrocarbon (S1) and source potential (S2) values indicated that most of the samples have good source rock qualities. On the basis of maximum hydrocarbon generation temperature (Tmax) and vitrinite reflectance (Ro), the investigated samples were found to be in mature and high-mature stages for hydrocarbon generation. The detected chromatograms were dominated by short (nC15–nC20)- to middle (nC20–nC25)-chain normal alkanes and were marked by a single peak with weak to no odd–even predominance. The C29ααα20R/C27ααα20R ratio varied between 1.14 and 1.35, and the gammacerane/hopane ratio ranged from 0.12 to 0.14, thus indicating a low-salinity reducing environment. Both the Late Carboniferous Taiyuan and the Early Permian Shanxi formations manifested a dominant source of higher plant as evidenced by the maceral compositions and biomarkers, while the Taiyuan Formation samples show a mixed source aquatic matter influenced by the transgression happened several times during the strata deposition. Moreover, the C29ααα20R/C27ααα20R ratio, ΣC21?/ΣC22+ ratios, and the distributions of C27-, C28-, and C29- steranes revealed that the Taiyuan Formation source rocks were composed of certain contents of aquatic organisms and algae under a more reducing environment.Li, Y., Zhu, X., Zhang, W., Zhu, D., Zhou, X., Zhang, L., 2019. Archaeal communities in the deep-sea sediments of the South China Sea revealed by Illumina high-throughput sequencing. Annals of Microbiology 69, 839-848.: Archaea have important roles in global biogeochemical circulation. Although archaeal diversity and their ecological significance in deep-sea environments in the South China Sea (SCS) have been investigated, archaeal communities in deep-sea sediments below 2000 m water depth in the SCS are not well documented. The objective of our work was to investigate archaeal community structure in the four sediments (named as SCS2, SCS5, SCS8, and SCS10) collected from the SCS below 2000 m water depth.Methods: Illumina high-throughput sequencing was employed to reveal archaeal community structure. Archaeal communities were evaluated with QIIM software.Result: Archaeal communities in the four sediments were dominated by Thaumarchaeota (55%), Bathyarchaeota (24%), Woesearchaeota (6%), Nanohaloarchaeota (4%), and Euryarchaeota (3%). Thaumarchaeota were abundant in the four samples. However, in SCS10, this phylum was almost exclusively represented. We revealed for the first time the presence of Nanohaloarchaeota in SCS2, SCS5, and SCS8. Comparative analysis showed that (1) the archaeal communities varied between the samples and (2) the samples varied between the samples. The detected archaea in each sample are known to be potentially participating in the carbon, nitrogen, and sulfur cycles, and methane metabolism.Conclusion: We present a comparative picture of archaeal communities, augmenting the current knowledge on archaeal diversity in deep-sea sediment environments in the SCS.Liang, S., Hou, Y., Wu, W., Li, L., Ren, S., 2019. New insights into the primary reaction products of Naomaohu coal via breaking weak bonds with supercritical ethanolysis. Energy & Fuels 33, 6294-6301. is an important energy source in the world, and its chemical structure is the basis of its application, especially for its pyrolysis and liquefaction. Supercritical ethanolysis is a type of chemical extraction that can effectively depolymerize some weak bonds in organic matter. In this work, new insights into the primary products of Naomaohu coal were studied with supercritical ethanolysis. The non-covalent and weak covalent bonds (such as ether and ester bonds) in the coal were broken to yield small molecular compounds (SMCs) with a conversion of 70.3% (dry and ash-free basis) at 370 °C. SMCs, including esters, alcohols, aldehydes, ethers, ketones, hydrocarbons (aromatic and aliphatic hydrocarbons), acids, phenols, and heteroatom compounds, were identified quantitively through gas chromatography/mass spectrometry. Fourier transform infrared spectroscopy and 13C nuclear magnetic resonance were used to characterize the structure of the coal and its ethanolysis residues. The structure characteristic of the coal was deduced through analyzing the SMCs and residues. Interestingly, the SMCs can reflect the primary reaction products of the coal during its pyrolysis or liquefaction.Lin, B., Liu, Z., Eglinton, T.I., Kandasamy, S., Blattmann, T.M., Haghipour, N., de Lange, G.J., 2019. Perspectives on provenance and alteration of suspended and sedimentary organic matter in the subtropical Pearl River system, South China. Geochimica et Cosmochimica Acta 259, 270-287. river systems accumulate, process, and transport huge quantities of organic matter (OM) from their catchments, part of which is exported to the ocean. Although this suite of processes comprises an important component of the global carbon cycle, integrated studies examining the nature and extent of OM processing on a basin-wide scale remain rare. Here, we provide an overview of provenance and composition of OM in suspended and deposited sediments within the Pearl River watershed in South China. We present new data on the organic carbon (OC) and total nitrogen (TN) contents, stable carbon and radiocarbon isotopic compositions of OC (δ13C and Fm), as well as grain size distribution and mineral-specific surface area of Pearl River sediments. These results are combined with published data on suspended particulate matter (SPM) and soil profiles in the Pearl River watershed in order to determine the provenance and transformation of OM in this large subtropical fluvial system.We find that the low 14C contents, expressed as fraction modern (Fm) values, in suspended (Fm: 0.58–0.87) and sedimentary OM (Fm: 0.38–0.82) are attributed to contributions from 14C-depleted soils, bedrock, as well as riverine primary productivity (Rpp) that utilizes 14C-depleted sources of dissolved inorganic carbon (DIC). For SPM, soil OM (Fm: 0.87?±?0.13) is inferred to be the dominant fraction during the wet season, whereas the contributions of Rpp (Fm: 0.86?±?0.04) and petrogenic OC (devoid of 14C) are enhanced during the dry season. This manifests itself in differences in OCsoil, OCRpp, and OCpetro contributions in SPM between wet and dry seasons (1.05?±?0.18 vs. 1.20?±?0.50%, 0.16?±?0.03 vs. 0.32?±?0.15% and 0.21?±?0.07 vs. 0.38?±?0.19%). During erosion and transport, the most labile OM in the top soil is rapidly degraded, as indicated by a stronger contribution from soil CO2 into riverine DIC during the wet season and flood event (39?±?1% and 45?±?3%) compared to the dry season (31?±?2%). River sediments are primarily accumulated during the wet season when suspended sediment fluxes are high. Refractory deep soil OM (Fm: 0.74?±?0.07) dominate in these sediments, whereas moderately labile soil OM components are further degraded during settling and storage. This sedimentary OM is predominantly composed of aged soil (92?±?4%), with a minor contribution from bedrock (7?±?4%) and negligible input from Rpp (0.2?±?0%). The longitudinal changes in the composition of suspended and sedimentary OM are mainly controlled by input of Rpp and ongoing degradation processes in the river system. The riverine particulate OC flux to the Pearl River estuary and ocean thus contains a mixture of soil, petrogenic and Rpp OM, all exhibiting relatively low Fm values. The riverine OM transformation and dynamics are important for the short-term carbon cycle, whereas the remaining signature and fate of the extensively processed, refractory OM has implications for the long-term carbon cycle.Lin, Y., Tang, D., Shi, X., Zhou, X., Huang, K., 2019. Shallow-marine ironstones formed by microaerophilic iron-oxidizing bacteria in terminal Paleoproterozoic. Gondwana Research 76, 1-18. microbial origin of Precambrian iron formations is debated due to the lack of direct fossil evidence. In order to reveal the genesis of ironstones under low-oxygen levels, integrative studies of sedimentology, petrography, mineralogy, and geochemistry were conducted on the intertidal to shallow subtidal ooidal and stromatolitic ironstones from the terminal Paleoproterozoic Chuanlinggou Formation (ca. 1.65–1.64?Ga) of North China, using microscopy, SEM, EDS, ICP-OES, ICP-MS and MC-ICP-MS techniques. Mineralogical study shows that the Fe-rich mineral is predominantly hematite that resulted from dehydration of amorphous Fe-oxyhydroxide during diagenesis. Petrographic observation indicates that the iron was oxidized and precipitated from seawater rather than sourced from terrestrial detritus. Basinward increases of the ironstone abundance, Eu anomalies (from 1.39 to 1.56) and δ56Fe values of the ironstones (from +0.5‰ to +1.0‰) suggest that the iron was mainly sourced from seafloor hydrothermal fluids, and partially oxidized and precipitated in shallow subtidal to intertidal environments. The common existence of Fe-oxide coated sheaths, spiral stalks, residual extracellular polymer substances (EPS) and other biogenic fabrics indicates that microaerophilic iron-oxidizing bacteria (FeOB) may have played an important role in precipitating the Chuanlinggou ironstones. The extremely low oxygen concentrations implied by the proliferation of microaerophilic FeOB in the shallow waters, the weak positive Ce anomalies (0.94–1.12) and low Mn concentrations in the ironstones are broadly consistent with the previous result of a Cr isotope study. Thus the establishment of a microaerophilic FeOB genetic model for the widespread Chuanlinggou ironstones in North China provides new insight into the origin of Precambrian iron formations and the redox evolution of ocean-atmosphere systems during the “Boring Billion”.Lingam, M., Loeb, A., 2019. Subsurface exolife. International Journal of Astrobiology 18, 112-141. study the prospects for life on planets with subsurface oceans, and find that a wide range of planets can exist in diverse habitats with ice envelopes of moderate thickness. We quantify the energy sources available to these worlds, the rate of production of prebiotic compounds, and assess their potential for hosting biospheres. Life on these planets is likely to face challenges, which could be overcome through a combination of different mechanisms. We estimate the number of such worlds, and find that they may outnumber rocky planets in the habitable zone of stars by a few orders of magnitude.Liu, A.G., McMahon, S., Matthews, J.J., Still, J.W., Brasier, A.T., Marosi, D., 2019. Petrological evidence supports the death mask model for the preservation of Ediacaran soft-bodied organisms in South Australia: Reply. Geology 47, e474-e474. mediated early diagenetic pyrite formation in the immediate vicinity of organic material has been the favored mechanism by which to explain widespread preservation of soft-bodied organisms in late Ediacaran sedimentary successions, but an alternative rapid silicification model has been proposed for macrofossil preservation in sandstones of the Ediacara Member in South Australia. We here provide petrological evidence from Nilpena National Heritage Site and Ediacara Conservation Park to demonstrate the presence of grain-coating iron oxides, framboidal hematite, and clay minerals along Ediacara Member sandstone bedding planes, including fossil-bearing bed soles. Scanning electron microscope (SEM), cathodoluminescence microscopy (CL), and petrographic data reveal that framboids and grain coatings, which we interpret as oxidized pyrite, formed before the precipitation of silica cements. In conjunction with geochemical and taphonomic considerations, our data suggest that anactualistically high concentrations of silica need not be invoked to explain Ediacara Member fossil preservation: We conclude that the pyritic death mask model remains compelling.Original paper: Liu, A.G., McMahon, S., Matthews, J.J., Still, J.W., and Brasier, A.T., 2019, Petrological evidence supports the death mask model for the preservation of Ediacaran soft-bodied organisms in South Australia: Geology, v. 47, p. 215– 218, . Comment by: Tarhan, L.G., Hood, A.V.S., Droser, M.L., Gehling, J.G., Briggs, D.E.G., Gaines, R.R., Robbins, L.J., Planavsky, N.J., 2019. Petrological evidence supports the death mask model for the preservation of Ediacaran soft-bodied organisms in South Australia: Comment. Geology 47, e473-e473., B., Bai, L., Chi, Y., Jia, R., Fu, X., Yang, L., 2019. Geochemical characterization and quantitative evaluation of shale oil reservoir by two-dimensional nuclear magnetic resonance and quantitative grain fluorescence on extract: A case study from the Qingshankou Formation in Southern Songliao Basin, northeast China. Marine and Petroleum Geology 109, 561-573. the content and geochemical characteristics of shale oil are two significant aspects of shale oil exploration and evaluation. This paper details the analysis of 32 shale samples extracted by sealed coring from the first member of the Upper Cretaceous Qingshankou Formation (K2qn1) in the Southern Songliao Basin, northeast China. Geochemical techniques including Rock-Eval pyrolysis, contents of total organic carbon (TOC) and clay mineral identification by X-ray diffraction (XRD) were performed on the samples. A total of 13 samples were further analyzed using two-dimensional nuclear magnetic resonance (2D NMR) and the quantitative grain fluorescence on extract (QGF-E) technique to determine the content and properties of different types of organic matter (OM) in the shale reservoir. The OM content and spectral intensity obtained from the NMR and QGF results were positively correlated with TOC content and pyrolysis S1 of the samples, respectively. In addition, the characteristic fluorescence parameters (R1, R2) of the shale extract and crude oil obtained by total scanning fluorescence (TSF) indicated that the crude oil in the studied shale reservoir was a thick-medium oil in the medium mature stage. The comprehensive experiment with the combined use of high-frequency 2D NMR and QGF technologies realized the quantitative characterization of shale oil composition and maturity, and demonstrated advantages of nondestructive, rapid and quantitative detection of OM, especially oil content in shale. New shale oil evaluation parameters obtained from these experiments, therefore, are more significant than traditional measurements such as Soxhlet extraction and pyrolysis.Liu, D., 2019. Carbon and hydrogen isotopic reversals in highly mature coal-derived gases: A case study of Paleozoic gases in the southern Ordos Basin, China. Geofluids 2019, 8608596. compositional carbon isotopic series δ13C-CH4<δ13C-C2H6<δ13C-C3H8<δ13C-C4H10 is common in thermogenic gases. With the exploration of deeper strata, however, isotopic reversals (δ13C-CH4>δ13C-C2H6>δ13C-C3H8) in overmature unconventional shale gases and conventional (coal-derived) gases have been identified. Paleozoic gases in the southern Ordos Basin, China, with partial or complete isotopic reversals, were studied as examples of isotopic fractionation in overmature coal-derived gases. Isotopic compositions of gases of different maturities from the Ordos Basin and shale gases from around the world were compared. Results indicate that carbon isotopic series are related to maturity. Complete isotopic reversal occurs mostly in regions with vitrinite reflectance . Where , almost all gases display partial isotopic reversal, with δ13C-CH4>δ13C-C2H6 or δ13C-C2H6>δ13C-C3H8. Carbon isotopic reversal in coal-derived gases is not caused by abiotic origin, the mixing of gases from different types of source rock, abiotic polymerization, wet gas cracking, and other mechanisms that contribute to reversal in shale gases. Based on the unique structure of coaly source rock and the geology of the Ordos Basin, closed-system aromatization-polycondensation reactions are considered the most likely cause of carbon isotopic reversal. During the reactions, isotopically light gases are generated by recombination of previously formed hydrocarbons and residual kerogen-coal. Hydrogen isotopic reversal in the southern Ordos Basin might also be caused by aromatization-polycondensation reactions.Liu, H., Li, J., Zhao, M., Li, Y., Chen, Y., 2019. Remediation of oil-based drill cuttings using low-temperature thermal desorption: Performance and kinetics modeling. Chemosphere 235, 1081-1088. bench-scale apparatus was used for the low-temperature thermal desorption (LTTD) treatment of oil-based drill cuttings (OBDCs). The effects of treatment temperature, treatment duration, sand/OBDCs mixing ratio, and initial oil content on the LTTD treatment performance were investigated. It was found that the petroleum hydrocarbons (PHCs) were barely left in the high-oil-content drill cuttings after LTTD (at 300?°C for 20?min), and thus the overall soil health was improved. The desorption kinetics models of PHCs under various conditions were established, and it was found that the LTTD of OBDCs followed nonlinear least-squares exponential kinetics (adjusted R2?>?0.9). The energy consumption models of LTTD treatment under different temperatures were also developed. The modeling results are of practical guiding significance and useful for designing effective LTTD treatment systems of OBDCs.Liu, H., Wang, Y., Jiang, Y., Yuan, F., Chen, K., Guo, Z., 2019. Quantification models of overpressuring in Paleogene source rocks of the Raoyang Depression, Bohai Bay Basin, China. Marine and Petroleum Geology 109, 607-622. progress in studies on the quantifications of overpressuring has been made during the past decades, and various quantitative models for the overpressure have been built based on overpressure transfer, tectonic extrusion, disequilibrium compaction, hydrocarbon generation, and other processes. In the Raoyang Depression of the Bohai Bay Basin in China, overpressure is mainly generated due to disequilibrium compaction and hydrocarbon generation. However, the overpressure-generation mechanism varies significantly in the overpressured formations and sags. The overpressure genesis in the Dongying Formation (Ed) occurs by disequilibrium compaction, but the overpressure mechanism in the first member (Es1) and third member (Es3) of the Shahejie Formation is a combination of disequilibrium compaction and hydrocarbon generation. The overpressure is caused by the difference in hydrocarbon generation before and after hydrocarbon expulsion. On the basis of the law of volume conservation, three quantitative models have been established for the under-compacted interval, the hydrocarbon-generation-to-expulsion interval, and the post-hydrocarbon-expulsion interval. The contribution of hydrocarbon generation differs in four sags developed in the Raoyang Depression due to differences in the hydrocarbon-generation capacity. Calculations based on these quantitative models indicated that the contributions of hydrocarbon generation to overpressure at the bottom of the Es1 and Es3 members in the Maxi Sag are 54.3% and 39.1%, respectively. The excessive pressure in the lower strata was stronger than that in the upper strata due to the fact that the contribution ratio of hydrocarbon generation to overpressure in the Es1 member is lower than that in the Es3 member, unlike in the case when the pressure in the upper strata is stronger than that in the lower strata. Therefore, it indicated that hydrocarbon generation plays an important role in the overpressure-generation mechanism.Liu, J., Jiang, Y., Yao, W., Jiang, X., Jiang, X., 2019. Molecular characterization of Henan anthracite coal. Energy & Fuels 33, 6215-6225. type of Chinese anthracite coal was analyzed by several analytical techniques such as Fourier transform infrared spectrum (FTIR), X-ray photoelectron spectroscopy (XPS), solid-state 13C nuclear magnetic resonance spectrum (NMR), and high-resolution transmission electron microscopy (HRTEM). Combining the experimental data, a reasonable macromolecular model of anthracite coal (C258H172O12N4S) was proposed. HRTEM results showed that the anthracite coal mainly contained aromatic laminates with different lattice sizes, with the length distribution characterized as 35.0% (<5.5 ?), 17.5% (5.5–7.4 ?), 22.5% (7.5–11.4 ?), and 10% (11.5–14.4 ?). The FTIR analysis suggested that ether, hydroxyl, and carbonyl groups were the main oxygenated functionalities. The ratio of these groups was approximately 4:3:3, which was consistent with the results of the XPS. On the basis of the rich analytical data, a three-dimensional molecular representation of the anthracite coal was constructed. Then, the properties of the model like NMR were simulated and exhibited a good agreement with the experimental spectrum in peak ranges and composition. The molecular model obtained in this work is useful for further studying the reaction mechanisms during the anthracite utilization processes, and the methodology adopted here can be extrapolated to other coal representations.Liu, L., Sun, Z., Zhang, L., Wu, N., Qin, Y., Jiang, Z., Geng, W., Cao, H., Zhang, X., Zhai, B., Xu, C., Shen, Z., Jia, Y., 2019. Progress in global gas hydrate development and production as a new energy resource. Acta Geologica Sinica - English Edition 93, 731-755. gas hydrates have been hailed as a new and promising unconventional alternative energy, especially as fossil fuels approach depletion, energy consumption soars, and fossil fuel prices rise, owing to their extensive distribution, abundance, and high fuel efficiency. Gas hydrate reservoirs are similar to a storage cupboard in the global carbon cycle, containing most of the world's methane and accounting for a third of Earth's mobile organic carbon. We investigated gas hydrate stability zone burial depths from the viewpoint of conditions associated with stable existence of gas hydrates, such as temperature, pressure, and heat flow, based on related data collected by the global drilling programs. Hydrate‐related areas are estimated using various biological, geochemical and geophysical tools. Based on a series of previous investigations, we cover the history and status of gas hydrate exploration in the USA, Japan, South Korea, India, Germany, the polar areas, and China. Then, we review the current techniques for hydrate exploration in a global scale. Additionally, we briefly review existing techniques for recovering methane from gas hydrates, including thermal stimulation, depressurization, chemical injection, and CH4–CO2 exchange, as well as corresponding global field trials in Russia, Japan, United States, Canada and China. In particular, unlike diagenetic gas hydrates in coarse sandy sediments in Japan and gravel sediments in the United States and Canada, most gas hydrates in the northern South China Sea are non‐diagenetic and exist in fine‐grained sediments with a vein‐like morphology. Therefore, especially in terms of the offshore production test in gas hydrate reservoirs in the Shenhu area in the north slope of the South China Sea, Chinese scientists have proposed two unprecedented techniques that have been verified during the field trials: solid fluidization and formation fluid extraction. Herein, we introduce the two production techniques, as well as the so‐called “four‐in‐one” environmental monitoring system employed during the Shenhu production test. Methane is not currently commercially produced from gas hydrates anywhere in the world; therefore, the objective of field trials is to prove whether existing techniques could be applied as feasible and economic production methods for gas hydrates in deep‐water sediments and permafrost zones. Before achieving commercial methane recovery from gas hydrates, it should be necessary to measure the geologic properties of gas hydrate reservoirs to optimize and improve existing production techniques. Herein, we propose horizontal wells, multilateral wells, and cluster wells improved by the vertical and individual wells applied during existing field trials. It is noteworthy that relatively pure gas hydrates occur in seafloor mounds, within near‐surface sediments, and in gas migration conduits. Their extensive distribution, high saturation, and easy access mean that these types of gas hydrate may attract considerable attention from academia and industry in the future. Herein, we also review the occurrence and development of concentrated shallow hydrate accumulations and briefly introduce exploration and production techniques. In the closing section, we discuss future research needs, key issues, and major challenges related to gas hydrate exploration and production. We believe this review article provides insight on past, present, and future gas hydrate exploration and production to provide guidelines and stimulate new work into the field of gas hydrates.Liu, R., Liu, Y., Chen, Y., Zhan, Y., Zeng, Q., 2019. Cyanobacterial viruses exhibit diurnal rhythms during infection. Proceedings of the National Academy of Sciences 116, 14077-14082.: To adapt to the daily light–dark cycle, diurnal rhythms are used by the photosynthetic cyanobacteria Prochlorococcus and Synechococcus, which are the most abundant photosynthetic organisms on earth. Field studies revealed that cyanobacterial virus (cyanophage) populations in the oceans showed transcriptional rhythms. To explore the underlying mechanism, we used cyanophage laboratory cultures to find that some showed adsorption rhythms and all showed transcriptional rhythms. We discovered that the cyanophage transcriptional rhythm is partially caused by the photosynthetic activity of host cells, explaining transcriptional rhythms of field cyanophage populations. Our study shows that cultured viruses have diurnal infection rhythms which are critical for understanding how light–dark cycles shape the interaction of cyanophages and their hosts in the oceans.Abstract: As an adaptation to the daily light–dark (diel) cycle, cyanobacteria exhibit diurnal rhythms of gene expression and cell cycle. The light–dark cycle also affects the life cycle of viruses (cyanophages) that infect the unicellular picocyanobacteria Prochlorococcus and Synechococcus, which are the major primary producers in the oceans. For example, the adsorption of some cyanophages to the host cells depends on light, and the burst sizes of cyanophages are positively correlated to the length of light exposure during infection. Recent metatranscriptomic studies revealed transcriptional rhythms of field cyanophage populations. However, the underlying mechanism remains to be determined, as cyanophage laboratory cultures have not been shown to exhibit diurnal transcriptional rhythms. Here, we studied variation in infection patterns and gene expression of Prochlorococcus phages in laboratory culture conditions as a function of light. We found three distinct diel-dependent life history traits in dark conditions (diel traits): no adsorption (cyanophage P-HM2), adsorption but no replication (cyanophage P-SSM2), and replication (cyanophage P-SSP7). Under light–dark cycles, each cyanophage exhibited rhythmic transcript abundance, and cyanophages P-HM2 and P-SSM2 also exhibited rhythmic adsorption patterns. Finally, we show evidence to link the diurnal transcriptional rhythm of cyanophages to the photosynthetic activity of the host, thus providing a mechanistic explanation for the field observations of cyanophage transcriptional rhythms. Our study identifies that cultured viruses can exhibit diurnal rhythms during infection, which might impact cyanophage population-level dynamics in the oceans.Liu, S.-S., Yang, K., Sun, Z.-L., Zheng, X., Bai, X., Liu, Z.-Y., 2019. A novel two-dimensional liquid chromatography system for the simultaneous determination of three monoterpene indole alkaloids in biological matrices. Analytical and Bioanalytical Chemistry 411, 3857-3870. present paper describes a novel two-dimensional liquid chromatography (2D-LC) system, which is comprised of a first-dimensional ion exchange chromatography (IEX1) column, trap column, and second-dimensional reversed-phase chromatography (RP2) column system. The biological sample is separated by the first-dimensional LC using an IEX column to remove interferences. The analytes are transferred to the trap column after heart-cutting. Then, the analytes are transferred to the second-dimensional LC using an RP2 column for further separation and ultraviolet detection. This 2D-LC system can offer a large injection volume to provide sufficient sensitivity and exhibits a strong capacity for removing interferences. Here, the determination of three monoterpene indole alkaloids (MIAs; gelsemine, koumine, and humantenmine) from Gelsemium in biological matrices (plasma, tissue, and urine) was used this 2D-LC system. After a rapid and easy sample preparation method based on protein precipitation, the sample was injected into the 2D-LC. The method was developed and validated in terms of the selectivity, LOD, LOQ, linearity, precision, accuracy, and stability. The sample preparation time for the three MIAs was 15?min. The LOD for these compounds was 10?ng/mL, which was lower than the developed HPLC methods. The results showed that this method had good quantitation performance and allowed the determination of gelsemine, koumine, and humantenmine in biological matrices. The method is rapid, exhibits high selectivity, has good sensitivity, and is low-cost, thus making it well-suited for application in the pharmaceutical and toxicological analysis of Gelsemium.Liu, S., Zuo, J., Lu, Y., Gao, L., Zhai, Y., Xu, W., 2019. Direct bacteria analysis using laserspray ionization miniature mass spectrometry. Analytical and Bioanalytical Chemistry 411, 4031-4040. atmospheric pressure laserspray ionization mass spectrometry (AP-LSI mini MS) has been developed and employed in the fast analysis of bacteria. Without using surfactants or any extracting methods, 21 foodborne bacteria from 12 genera were directly analyzed. Typical fingerprints of small molecules and lipids were detected and recognized in the mass spectra with high reproducibility. Furthermore, a supervised multivariate statistics method, orthogonal partial least squares (OPLS), was applied, and these bacteria could be differentiated at both genus and species levels. With improved performance in the future, AP-LSI mini MS could be a simple, effective, and fast approach for direct bacteria analysis on the field.Liu, X., Zhan, J., Jing, X., Zhou, S., Lovley, D.R., 2019. A pilin chaperone required for the expression of electrically conductive Geobacter sulfurreducens pili. Environmental Microbiology 21, 2511-2522. controlling the expression of the electrically conductive pili (e‐pili) of Geobacter species are of interest because of the important role of e‐pili in diverse biogeochemical processes, anaerobic digestion and electromicrobiological applications. We investigated the function of the protein, designated Spc (short pilin chaperone), encoded by the gene immediately downstream from the gene for PilA, the monomer that assembles into e‐pili. Multiple lines of evidence suggest that Spc forms an oligomer that is associated with the inner membrane. Mutating the start codon of spc to prevent translation increased the transcript abundance of pilA but greatly diminished the abundance of PilA, and e‐pili could no longer be detected. Cross‐linking, protein capture and two‐hybrid studies demonstrated that Spc and PilA interacted. Two sites in PilA for electrostatic interaction with Spc were identified. The results demonstrate that Spc is required for PilA stability prior to incorporation into e‐pili, suggesting that Spc has a chaperone function that may be specific to the relatively short PilA monomers that assemble into e‐pili. These results are important for identifying microorganisms likely to express e‐pili from (meta)genomic data and for the construction of microbial strains expressing e‐pili.Longo, G.M., Piccinni, V., Longo, S., 2019. Evaluation of CaSO4 micrograins in the context of organic matter delivery: thermochemistry and atmospheric entry. International Journal of Astrobiology 18, 345-352. this paper, anhydrous calcium sulphate CaSO4 (anhydrite) is considered as a carrier material for organic matter delivery from Space to Earth. Its capability of incorporating important fractions of water, leading to different species like bassanite and gypsum, as well as organic molecules; its discovery on Mars surface and in meteorites; the capability to dissipate much energy by its chemical decomposition into solid (CaO) and gaseous (SO3) oxide, make anhydrite a very promising material in an astrobiological perspective. Since chemical cooling has been recently considered by some of the present authors for the case of Ca/Mg carbonates, CaSO4 can be placed into a class of ‘white soft minerals’ (WSM) of astrobiological interest. In this context, CaSO4 is evaluated here by using the atmospheric entry model previously developed for carbonates. The model includes grain dynamics, thermochemistry, stoichiometry, radiation and evaporation heat losses. Results are discussed in comparison with MgCO3 and CaSO4 and show that sub-mm anhydrite grains are potentially effective organic matter carriers. A Monte Carlo simulation is used to provide distributions of the sulphate fraction as a function of altitude. Two-zone model results are presented to support the isothermal grain hypothesis.Losacco, G.L., Veuthey, J.-L., Guillarme, D., 2019. Supercritical fluid chromatography – mass spectrometry: Recent evolution and current trends. TrAC Trends in Analytical Chemistry 118, 731-738. fluid chromatography (SFC) has recently experienced renovated impulse from research groups. Its hyphenation to mass spectrometers (MS) proved to be of significant importance in catalysing interest from researchers. In contrast to liquid chromatography (LC), the coupling of SFC-MS requires the use of an interface in order to deal efficiently with the decompression of supercritical CO2 and possible precipitation issues of samples while entering the ionization chamber. The most common SFC-MS interfaces employ an additional sheath pump that reduces sample precipitation. However, there are still issues in dealing with the CO2 decompression phenomenon, with different solutions being given. Matrix effects (MEs) under SFC-MS have proved to be quite different from those generally observed in LC-MS, with ion suppression being the main form of ME. Nonetheless, SFC-MS is capable of reaching comparable sensitivity values to LC-MS, and in some cases performing even better. Several applications have been recently developed for SFC-MS, spacing from the analysis of plant extracts, biological matrices for anti-doping and forensic purposes, as well as highly polar compounds such as carbohydrates and endogenous metabolites.Losch, A., 2019. The need of an ethics of planetary sustainability. International Journal of Astrobiology 18, 259-266. concept of sustainability is widely acknowledged as a political guideline. Economic, ecological, social and cultural aspects of sustainability are already under discussion. Current space mining efforts demand that the discussion become a broader one about ‘planetary sustainability’, including the space surrounding Earth. To date, planetary sustainability has mainly been used with reference to Earth only and I will extend it here, elaborating on a similar NASA initiative. This article (1) sketches the contemporary economic–political initiatives which call for a special reflection of Earth's location in space, and then (2) discusses the meaning of the concept of sustainability in this context. Next, (3) I relate the discussion to the issue of planetary and environmental protection, before, (4) finally, presenting a philosophical and theological perspective that seems particularly able to broach the issue of the multiple dimensions of sustainability in this context. This is the concept of constructive-critical realism. My overview of the topic concludes with (5) a summarizing outlook.Lu, S., Luo, X., Du, S., He, B., Fu, H., Liu, K., 2019. Discovery and analysis of shale gas in a Carboniferous reservoir and its enrichment characteristics in the northern Nanpanjiang Depression, Guizhou Province, China. Acta Geologica Sinica - English Edition 93, 561-572. gas resources are considered to be extremely abundant in southern China, which has dedicated considerable attention to shale gas exploration in recent years. Exploration of shale gas has considerably progressed and several breakthroughs have been made in China. However, shale gas explorations are still scarce. Summary and detailed analysis studies on black shale reservoirs are still to be performed for many areas. This lack of information slows the progress of shale gas explorations and results in low quantities of stored black shale. The Carboniferous Dawuba Formation, which is widely distributed and considerably thick, is one of the black shale formations targeted for shale gas exploration in southern China in the recent years. The acquisition and analysis of total organic carbon, vitrinite reflectance, types of organic matter, mineral composition, porosity, and permeability are basic but important processes. In addition, we analyzed the microscopic pores present in the shale. This study also showesd the good gas content of the Dawuba Formation, as well as the geological factors affecting its gas content and other characteristics. To understand the prospect of exploration, we compared this with other shale reservoirs which have been already successfully explored for gas. Our comparison showesd that those shale reservoirs have similar but not identical geological characteristics.Luis-Vargas, M.N., López-Martínez, R.A., Vilchis-Nestor, A.R., Daza, R., Alcántara-Hernández, R.J., 2019. Bacterial insights into the formation of opaline stromatolites from the Chimalacatepec lava tube system, Mexico. Geomicrobiology Journal 36, 694-704. lithifying systems are excellent models to study biomineralization in the dark. The Chimalacatepec Lava Tube System in Mexico harbors diverse biospeleothems where previous studies suggest that the formation of opaline terrestrial stromatolites is related to microorganisms in contiguous mats. However, there is no information regarding their characterization and their role in mineral formation. In this study, we characterized the bacterial and archaeal composition of microbial mats and stromatolites and suggested the main processes involved in the genesis of opaline stromatolites. Our results showed that the microbial mats and stromatolites have a similar 16S rRNA gene composition, but stromatolites contain more Actinobacteria, which have been previously found in other lava tubes together with other key bacteria. Microorganisms found here belonged to groups with the potential to fix carbon and degrade organic matter. We propose that the synergic interaction of autotrophic and heterotrophic microorganisms that thrive in the dark might be inducing carbonate precipitation within the Ca-enriched extracellular polymeric substances (EPS), generating opal-A and calcite laminae. The similar 16S rRNA gene fingerprint and the presence of potential pathways that induce carbonate precipitation in opaline stromatolites and microbial mats suggest that microbial mats lithify and contribute to the stromatolite biotic genesis.Lüning, S., Ga?ka, M., Vahrenholt, F., 2019. The Medieval Climate Anomaly in Antarctica. Palaeogeography, Palaeoclimatology, Palaeoecology 532, 109251. Medieval Climate Anomaly (MCA) is a well-recognized climate perturbation in many parts of the world, with a core period of 1000–1200?CE. Here we are mapping the MCA across the Antarctic region based on the analysis of published palaeotemperature proxy data from 60 sites. In addition to the conventionally used ice core data, we are integrating temperature proxy records from marine and terrestrial sediment cores as well as radiocarbon ages of glacier moraines and elephant seal colonies. A generally warm MCA compared to the subsequent Little Ice Age (LIA) was found for the Subantarctic Islands south of the Antarctic Convergence, the Antarctic Peninsula, Victoria Land and central West Antarctica. A somewhat less clear MCA warm signal was detected for the majority of East Antarctica. MCA cooling occurred in the Ross Ice Shelf region, and probably in the Weddell Sea and on Filchner-Ronne Ice Shelf. Spatial distribution of MCA cooling and warming follows modern dipole patterns, as reflected by areas of opposing temperature trends. Main drivers of the multi-centennial scale climate variability appear to be the Southern Annular Mode (SAM) and El Ni?o-Southern Oscillation (ENSO) which are linked to solar activity changes by nonlinear dynamics.Luo, M., Gieskes, J., Chen, L., Scholten, J., Pan, B., Lin, G., Chen, D., 2019. Sources, degradation, and transport of organic matter in the New Britain Shelf-Trench Continuum, Papua New Guinea. Journal of Geophysical Research: Biogeosciences 124, 1680-1695.: Hadal trenches are considered as depocenters for organic matter and hotspots for microbial diagenetic activity. Here, we explore the sources, degradation, and transport of organic matter in the shelf‐trench continuum using seven short sediment cores collected along two transects with water depths ranging between 1,553 and 8,901 m in the New Britain Trench area, Papua New Guinea. Carbon isotopic compositions (δ13C) and radiocarbon contents (Δ14C) of sedimentary organic matter accompanied by total organic carbon/total nitrogen ratios suggest an important contribution from the preaged soil organic matter mixed by the marine algae and terrigenous C3 vascular plants. In addition, the trench axis sites are characterized by elevated accumulation of terrigenous organic materials. Rates of organic matter mineralization approximated by dissolved inorganic carbon fluxes at the sediment‐water interface reveal an approximately threefold higher rate at the trench axis sites than the abyssal sites. 210Pbxs profiles and burial of carbonate (up to 50%) at both trench axis sites reflect recent occurrence of mass‐wasting events possibly induced by earthquakes, which is responsible for the transport of preaged, terrigenous organic matter to the trench bottom. This tectonically triggered deposition event, which was also shown to occur in the Japan Trench, the Tonga Trench, and probably in many other trenches, is likely to efficiently transport terrigenous organic matter to hadal trenches, thereby underpinning the importance of terrigenous organic matter burial in hadal trenches for the ocean organic carbon budget. Furthermore, we hypothesize that hadal trenches may host a distinct microbial community that is capable of feeding on old, refractory terrigenous organic matter.Plain Language Summary: Hadal trenches that refer to seafloor areas covered by a water column with depths >6,000 m have been proposed as depocenters of organic material and hotspots for organic matter mineralization. In this study, we show that the sediments in the New Britain Shelf‐Trench continuum with water depths ranging between 1,553 and 8,901 m receive a significant input of preaged soil organic matter mixed by marine algae and terrigenous C3 vascular plants. Recent occurrence of mass‐wasting events possibly induced by earthquakes accounts for the efficient burial of terrigenous organic matter and carbonate into the trench bottom. We highlight the importance of terrigenous organic matter burial in hadal trenches for the ocean organic carbon budget. Furthermore, we hypothesize that hadal trenches may host a distinct microbial community that is capable of feeding on old, refractory terrigenous organic matter, which provides an additional possible explanation for the elevated diagenetic activity at the trench axis apart from the extant postulation of preferential focusing of relatively labile organic matter in the trench axis.Luo, S., Jin, B., Lutkenhaus, J.L., Nasrabadi, H., 2019. A novel pore-size-dependent equation of state for modeling fluid phase behavior in nanopores. Fluid Phase Equilibria 498, 72-85. thermodynamic behavior of fluids confined in nanopores differs from that of bulk fluid by the fluid-pore wall interaction. Inspired by the heterogeneous distribution and layering transitions from fluid-wall interactions, we have developed a pore-size-dependent equation of state (EOS) extended from the Peng-Robinson equation of state (PR EOS) by describing the confined fluid as distinct populations of surface-adsorbed and core fluid. The surface-adsorbed fluid physically corresponds to two surface-adsorbed layers and is therefore considered to interact with the pore wall through a dual-square-well (DSW) potential function. The presented EOS requires only one additional parameter of confinement energy (εsf) beyond PR EOS, and it needs to be determined from experimental data. Using adsorption and differential scanning calorimetry experiments, we determine the confinement parameter εsf for nitrogen, carbon dioxide, n-alkanes of methane to n-tetradecane, with respect to surfaces of native silica and silylated silica. The resulting database of confinement parameters is presented. This EOS models adsorption isotherms, phase transition temperature, and phase transition-pore size relations, in agreement with experimental data. The EOS is shown to be a unified tool for modeling the fluid phase behavior in nanopores.Lutz, A., Mohr, C., Le Breton, M., Lopez-Hilfiker, F.D., Priestley, M., Thornton, J.A., Hallquist, M., 2019. Gas to particle partitioning of organic acids in the boreal atmosphere. ACS Earth and Space Chemistry 3, 1279-1287. time-of-flight mass spectrometer (HR–CI–ToF–MS) with the filter inlet for gases and aerosol (FIGAERO). Specifically, the partitioning coefficients of 640 components with unique molecular composition were calculated from an assumed linear relationship between [particle]/[gas] versus the mass of the organic fraction (Morg) according to Raoult’s law, i.e., equilibrium phase partitioning. We demonstrate that, using the full data set, most of the compounds do not follow a linear relationship. This is especially the case for low- and high-molecular-weight species. Using a subset of the data, with concurrent low sulfate ambient observations ([SO42– < 0.4 μg m–3), the relationship improved significantly and Ki could be derived from the slope of a linear regression to the data. The 100 species with the highest R2 (≥0.7) of this regression are presented. The restrictions during high sulfate conditions can be explained by changes in either the equilibrium conditions (e.g., the activity coeffient, γi) or uptake kinetics (mass transfer limitation). This study demonstrates that partitioning of compounds in the complex ambient atmosphere follows ideal Raoult’s law for some limited conditions and stresses the need for studies also in more polluted environments.Lyu, X., Jiang, Y., Liu, J., Xu, T., 2019. Geochemical characteristics and hydrocarbon generation potential of the first member of Shahejie Formation (E2s1) source rocks in the Dongpu Depression, East China. Geological Journal 54, 2034-2047. Dongpu Depression, containing huge amounts of hydrocarbons, is a typical petroliferous province in the Bohai Bay Basin, east China. As one set of the main source rocks, the first member of Shahejie Formation (E2s1) shows huge exploration potential with approximately 0.83 × 108 t resources remaining to be discovered. However, the geochemical characteristics and thermal evolution history of E2s1 source rocks have still not been determined. In this study, the sedimentary features were firstly analysed based on the geological data. Then the organic matter abundance, kerogen type, and thermal maturity of E2s1 source rocks in the present day were evaluated according to the Rock‐Eval pyrolysis, micro‐components of kerogen, total organic carbon (TOC), and vitrinite reflectance analysis. Furthermore, the evolution of thermal history and hydrocarbon generation was determined using the PetroMod procedure. The results show that dark mudstones and salt rocks were well developed in E2s1, which are propitious for organic matter to grow and preserve. E2s1 source rocks contain abundant organic matter and moderate to good generative source rock potential. E2s1 source rocks mainly consist of Type II kerogen and have entered early to maturation stage for hydrocarbon generation. Due to the limited buried depth, E2s1 source rocks only attained lower thermal maturity and generated finite hydrocarbons. The initial rapid subsidence and the second rift after uplift erosion resulted in the higher geo‐temperature at the end of E3d and the present day. Corresponding to the geo‐temperature evolution, there are two stages of hydrocarbon generation for E2s1 source rocks: The first stage was in the late E3d period, and the late stage was from the late Neogene to the present day. Moreover, the hydrocarbon generation rate and quantity of the late stage are much higher than the first stage, indicating the major hydrocarbon generation stage. Due to the limited hydrocarbon generation capacity, oils generated from E2s1 source rocks are low maturity; thus, it cannot migrate for a long distance and only accumulated around the sag belts.Ma, C., Chen, X., Zhang, J., Zhu, Y., Kalkhajeh, Y.K., Chai, R., Ye, X., Gao, H.-j., Chu, W., Mao, J.-d., Thompson, M.L., 2019. Linking chemical structure of dissolved organic carbon and microbial community composition with submergence-induced soil organic carbon mineralization. Science of The Total Environment 692, 930-939. research has been devoted to investigating how water-extractable organic carbon (DOC) concentration and microbial activity regulate soil organic carbon (SOC) mineralization when soils are saturated with water. However, the relationships of DOC chemical structure and microbial community composition with SOC mineralization, as well as the relative contributions of microbial decomposers and their substrates on the mineralization rate have rarely been examined. In a laboratory experiment, we incubated two typical cropland soils (an Entisol and a Mollisol) of China for 360?days under submerged and non-submerged conditions, and we evaluated the concentration and chemical structure of soil DOC, soil microbial metabolic potential and community composition by using total C/N analysis, solution-state 1H NMR, Biolog EcoPlates, and 16S rRNA amplicon sequencing, respectively. The results showed that submergence significantly increased DOC concentration (P?<?0.01) and microbial activity (P?<?0.001) and changed DOC chemical structure in the Entisol (P?<?0.01). In the Mollisol, it significantly increased the rate (P?<?0.01) and cumulative extent (P?<?0.001) of SOC mineralization and DOC concentration (P?<?0.01) as well as altering the composition of the microbial community (P?<?0.001). Moreover, the SOC mineralization rate was better explained by microbial community composition (Entisol: SPC?=??0.71, P?<?0.001; Mollisol: SPC?=?0.92, P?<?0.001) than by DOC concentration (Entisol: SPC?=?0.21, P?>?0.05; Mollisol: SPC?=?0.30, P?<?0.05) or DOC chemical structure (Entisol: SPC?=?0.12, P?>?0.05; Mollisol: SPC?=??0.45, P?<?0.001). Our study revealed that the bacterial community composition had a close relationship to the rate of submergence-induced SOC mineralization in both soils, but only DOC concentration and chemical structure were effective predictors of mineralization rate in the low-pH Mollisol.Ma, Y., Lu, Y., Liu, X., Zhai, G., Wang, Y., Zhang, C., 2019. Depositional environment and organic matter enrichment of the lower Cambrian Niutitang shale in western Hubei Province, South China. Marine and Petroleum Geology 109, 381-393. is important to consider the influences of depositional environment on lithofacies characteristics, lithofacies distribution patterns, and organic matter enrichment when defining reservoir properties and predicting “favorable reservoirs” and “sweet spots”. In this study, we examined the Niutitang shale of the early Cambrian Niutitang Formation in western Hubei Province, middle Yangtze Block, to understand how depositional environment controlled organic matter accumulation in the Niutitang shale. Through a combination of detailed sedimentologic investigations with geochemical analyses, we identified four primary lithofacies, siliceous shale, siliceous-clay mixed shale, calcareous shale, and argillaceous shale, from the Y1 drill core. The sedimentological analyses, including systematic observations of the color of fresh rocks, grain size, sedimentary textures and structures, biogenic and diagenetic (e.g., veins and pyrite) characteristics in cores and thin sections with mineralogical analyses by X-ray diffraction (XRD), and changes in geochemical proxies, including TOC (wt.%), MoEF, UEF, Ni/Al and Zn/Al, suggest that siliceous shale and siliceous-clay mixed shale were deposited in euxinic and anoxic deep water with high surficial paleoproductivity which primarily controlled by long term global sea level changes, and that the calcareous shale and argillaceous shale were deposited in shallow and oxygen-rich water conditions with low energy and low paleoproductivity in the surface water. The Niutitang shale changed from the siliceous shale-dominated lithofacies association (LA1), to the argillaceous shale-dominated lithofacies association (LA2), and then back to the siliceous shale-dominated lithofacies association (LA1), suggesting a variation of sedimentary environment from euxinic–anoxic deep-water environment (highstand), to relatively oxic and shallow water environment (lowstand), and then back to euxinic–anoxic deep-water environment (highstand). This may reflect changes in sea level and mechanisms of organic matter enrichment during sea level highstand and lowstand. The low Mo/TOC values of the siliceous shale and siliceous-clay mixed shale lithofacies are similar to the Mo/TOC values of marine sediments in Framvaren Fjord, suggesting that the study area was located in a moderately restricted basin during deposition of the Niutitang shale. The Fe/Ti and Al/(Al + Fe) ratios and the Al–Fe–Mn diagram combined with our detailed petrographic studies and the good correlation between TOC and quartz contents are indicative of a mainly biogenic origin with a minor detrital source for the silica in the Niutitang shale. TOC is well correlated to MoEF, UEF, Ni/Al and Zn/Al values in LA1, but it is only moderately correlated to MoEF and UEF values and weakly correlated to Ni/Al and Zn/Al values in LA2. The correlation relationships suggest that good preservation in euxinic–anoxic water conditions and high primary paleoproductivity were the major controlling factors of organic matter enrichment, whereas organic matter accumulation during sea level lowstand was mainly controlled by water redox conditions because primary paleoproductivity remained persistently low in the more restricted basin with shallow water and limited nutrient upwelling. The correlations between TOC content and clay minerals within the different lithofacies associations suggest that adsorption of carbon components by clay minerals promoted the accumulation of organic matter to various extents in LA2 but probably did not impact organic matter enrichment in LA1.Maccone, C., 2019. Life expectancy and life energy according to Evo-SETI theory. International Journal of Astrobiology 18, 36-46. paper is profoundly innovative for the Evo-SETI (Evolution and SETI) mathematical theory. While this author's previous papers were all based on the notion of a b-lognormal, that is a probability density function in the time describing one's life between birth and ‘senility’ (the descending inflexion point), in this paper the b-lognormals range between birth and peak only, while a descending parabola covers the lifespan after the peak and down to death. The resulting finite curve in time is called a LOGPAR, a nickname for ‘b-LOGnormal and PARabola’. The advantage of such a formulation is that three variables only (birth, peak and death) are sufficient to describe the whole Evo-SETI theory and the senility is discarded forever and so is the normalization condition of b-lognormals: only the shape of the b-lognormals is kept between birth and peak, but not its normalization condition.In addition, further advantages exist:1) The notion of ENERGY becomes part of Evo-SETI theory. This is in addition to the notion of ENTROPY already contained in the theory as the Shannon Information Entropy of b-lognormals, as it was explored in this author's previous papers. Actually, the LOGPAR may now be regarded as a POWER CURVE, i.e. a curve expressing the power of the living being to which it refers. And this power is to be understood both in the strict sense of physics (i.e. a curve measured in Watts) and in the loose sense of ‘political power’ if the logpar refers to a Civilization.Then the integral in the time of this power curve is, of course, the ENERGY either absorbed or produced by the physical phenomenon that the LOGPAR is describing in the time. For instance, if the logpar shows the time evolution of the Sun over about 10 billion years, the integral of such a curve is the energy produced by the Sun over the whole of its lifetime. Or, if the logpar describes the life of a man, the integral is the energy that this man must use in order to live.2) The PRINCIPLE OF LEAST ENERGY, reminiscent of the Principle of Least Action, i.e. the key stone to all Physics, also enters now into the Evo-SETI Theory by virtue of the so-called LOGPAR HISTORY FORMULAE, expressing the b-lognormal's mu and sigma directly in terms of the three only inputs b, p, d. The optimization of the lifetime of a living creature, or of a Civilization, or of a star, is obtained by setting to zero the first derivative of the area under the logpar power curve with respect to sigma. That yields the best value of both mu and sigma fulfilling the Principle of Least Energy for Evo-SETI Theory.3) We also derive for the first time a few more mathematical equations related to the ‘adolescence’ (or ‘puberty’) time, i.e. the time when the living organism acquires the capability of producing offsprings. This time is defined as the abscissa of ascending inflection point of the b-lognormal between birth and peak. In addition, we prove that the straight line parallel to the time axis and departing from the puberty time comes to mean the ‘Fertility Span’ in between puberty and the EOF (End-Of-Fertility time), which is where the above straight line intersects the descending parabola. All these new results apply well to the description of Man as the living creature to which our Evo-SETI mathematical theory perfectly applies.In conclusion, this paper really breaks new mathematical ground in Evo-SETI Theory, thus paving the way to further applications of the theory to Astrobiology and SETI.Machain-Castillo, M.L., Ruiz-Fernández, A.C., Gracia, A., Sanchez-Cabeza, J.A., Rodríguez-Ramírez, A., Alexander-Valdés, H.M., Pérez-Bernal, L.H., Nava-Fernández, X.A., Gómez-Lizárraga, L.E., Almaraz-Ruiz, L., Schwing, P.T., Hollander, D.J., 2019. Natural and anthropogenic oil impacts on benthic foraminifera in the southern Gulf of Mexico. Marine Environmental Research 149, 111-125. Campeche Sound is the major offshore oil producing area in the Southern Gulf of Mexico (SGoM). To evaluate the impact of oil related activities in the ocean floor sediments, we analyzed the geochemical (major and trace element, organic carbon and hydrocarbon concentrations) and biological (benthic foraminifera) composition of 62 superficial sediment samples, from 13 to 1336?m water depth. Cluster and Factor analysis of all the variables indicate that their distribution patterns are mainly controlled by differences between the terrigenous and carbonate platforms in the SGoM. Benthic foraminiferal assemblages were abundant and diverse, and their distribution patterns are mainly determined by water depth and sedimentary environment. However, most of the abundant species are opportunistic and/or low-oxygen tolerant, and many of their tests show oil stains and infillings, characteristic of oil polluted locations, suggesting the environment has been modified by natural seepage or oil-related activities. To determine if these conditions are natural or anthropogenic in origin, pre - industrial settings should be studied. Organic carbon (Corg) content (0.6–2.9%) and total hydrocarbon concentrations (PAHs 1.0–29.5?μg?kg?1) were usually higher around the oil platforms area, the natural hydrocarbon seeps (“chapopoteras”) area and offshore rivers, but there is no accumulation of oil related trace elements in these areas. However, the comparison with international sediment quality benchmarks indicates that Cd, Cr and Ni concentrations are above the threshold effect level, and also As, Ba and Cu are above the probable effect level benchmarks, which indicate that these element concentrations might be of potential ecological concern. Comprehensive studies involving different proxies, and assessing pre-industrial conditions, must be undertaken before assessing environmental health of marine benthic ecosystems.Mackensen, A., Schmiedl, G., 2019. Stable carbon isotopes in paleoceanography: atmosphere, oceans, and sediments. Earth-Science Reviews 197, 102893. is one of the key elements in organisms and non-living compounds on Earth. Carbon dioxide and methane are important greenhouse gases in the atmosphere, dissolved inorganic (DIC) and organic carbon (DOC) determine water biogeochemistry, and carbonates are major constituents of marine sediments. Stable carbon isotope ratios (13C/12C), expressed as δ13C values, are widely used in modern Earth sciences. δ13CCO2 values of atmospheric carbon dioxide reflect global climate evolution and change. Marine δ13CDIC is used as water-mass tracer and helps quantifying the anthropogenic CO2 uptake of the ocean. The δ13C values of fossil planktic and benthic carbonates indicate changes in circulation pattern and deep-water ventilation of ancient oceans, as well as paleoproductivity at the sea surface and methane release at the sea floor. The δ13COM values of sedimentary organic matter (OM) and compound-specific δ13C values of molecular organic biomarkers indicate whether the organic carbon is of marine or terrestrial provenience. Secular δ13C variations and excursions in carbonates are important stratigraphic marker and tie points.Here we review the application of stable carbon isotope ratios in ocean water and biogenic carbonates as proxies in paleoceanography, including the atmospheric and sedimentary reservoirs oceanic carbon is in exchange with. Due to the wide use of δ13C values in Earth sciences, this overview necessarily does not claim to be complete; rather we focus on field-based stable carbon isotope research and its significance in paleoceanography. This may assist in evaluating general circulation model results and foster development of new innovative proxies.Madikizela, L.M., Ncube, S., Chimuka, L., 2019. Recent developments in selective materials for solid phase extraction. Chromatographia 82, 1171-1189. success of any analytical method depends largely on the sample preparation technique which is usually employed for the extraction and pre-concentration of the target analyte from a sample matrix. In this context, solid-phase extraction has been greatly explored by various researchers in many scientific fields including environmental analysis of pollutants, as well as analysis of food and biological samples. One of the solid-phase extraction drawbacks observed over the years is its inability to selectively extract the target analytes from the sample matrix, which could have a consequence of prolonging the analysis times and have negative effect on the analytical data. In this paper, recent trends starting from the work published in 2014–2018 in selective solid-phase extraction are critically reviewed while interesting studies prior to 2014 are mentioned. Solid-phase extraction sorbents that have been revealed in greater extent in literature to offer better selectivity are molecularly imprinted polymers and nano sorbents. Other sorbents reviewed in this work include composite materials which are sometimes designed for improving the adsorption capacity as well as selectivity. Mixed-mode ion-exchange polymers categorized as class selective sorbents have also been reviewed and recent applications are cited. Moreover, a broad discussion on miniaturization, new inventions and future of selective solid-phase extraction utilizing different sorbents in various sample matrices is outlined.Mahmoudvand, S., Shahsavani, B., Parsaei, R., Malayeri, M.R., 2019. Prediction of asphaltene precipitation upon injection of various gases at near-wellbore conditions: A simulation study using PC-SAFT EoS. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 74, 63. depletion of oil reservoirs and increased global oil demand have given impetus to employ various secondary and tertiary oil recovery methods. Gas injection is widely used in both secondary and tertiary modes, though the major problem associated with this process is the precipitation and deposition of asphaltene, particularly at near-wellbore conditions. In-depth knowledge of asphaltene phase behavior is therefore essential for the prediction of asphaltene precipitation. Previous studies reported the impact of gas injection on asphaltene phase behavior, but the knowledge of precipitation of asphaltene as a function of different mole fractions of injected gas is also imperative. In this study, the thermodynamic model of PC-SAFT EoS is used to discern the phase equilibrium of asphaltene by analyzing the asphaltene drop-out curve during gas injection. Asphaltene drop-out curves of two different live oil samples are analyzed by injecting CO2, CH4, and N2 gases at different mole percentages and temperatures. The results revealed that PC-SAFT EoS can serve as a reliable tool for estimating bubble pressure and asphaltene onset pressure for a wide range of temperatures, pressures, and compositions. The simulation results for the injection of CO2, CH4, and N2 also showed that CO2 gas gives minimum asphaltene precipitation. It reduces the size of the drop-out curve or moves it toward higher pressures. CH4 and N2 expand the drop-out curve by raising the upper onset point. CH4 increases the maximum point of the drop-out curve for two types of oil studied (A and B) at two different temperatures. N2 raises the maximum point of oil type “A” by approximately 57% at 395 K, while it has no effect on the maximum point of oil type “B”. In addition, reducing the temperature resulted in either decrease or increase of asphaltene solubility, demonstrating that the impact of temperature on asphaltene precipitation is closely related to the composition of the crude.Mahoney, C., M?rz, C., Buckman, J., Wagner, T., Blanco-Velandia, V.-O., 2019. Pyrite oxidation in shales: Implications for palaeo-redox proxies based on geochemical and SEM-EDX evidence. Sedimentary Geology 389, 186-199. oxidation in marine shales during weathering has been widely studied, however, the effects of this process on geochemical proxies commonly used to reconstruct ocean redox conditions, or the details of pyrite oxidation at the mineral grain scale, have not received much scientific attention. We conducted a four-week laboratory experiment designed to stimulate pyrite oxidation at shale outcrops, and to assess effects on the chemical phase of iron and sulphur in the samples both in bulk sediments (useful for comparison to palaeo-environmental geochemistry) and at a finer scale (to gain a better understanding of the nature of these changes). Geochemical and scanning electron microscopy (SEM) techniques provide evidence for pyrite oxidation, carbonate dissolution, and iron (oxyhydr)oxide formation during the experiment. The net effect of the experiment on the ratio of highly reactive iron phases (FeHR) to total iron (FeT) is minimal (?0.03% difference), suggesting that this redox proxy behaves relatively conservatively during weathering. The effect of weathering on the ratio of pyrite-bound iron to highly reactive iron (FePY/FeHR), used to investigate the availability of sulphur, in contrast, is pronounced (up to 32.5% difference) due to the oxidation of pyrite and the precipitation of iron (oxyhydr)oxides in the shale samples. Electron microscopy provides evidence that iron (oxyhydr)oxides precipitated in situ as rims around cores of pyrite particles, “passivating” and protecting them from further oxidation. The quantification of these partly oxidised pyrite particles is now possible using a novel automated particle analysis method coupled to chemical mapping, developed in this study. We conclude that this method can be of wide use, both to quantify pyrite oxidation, and assess the significance of FePY/FeHR at measured in shale outcrop samples.Mahzari, P., Jones, A.P., Oelkers, E.H., 2019. An integrated evaluation of enhanced oil recovery and geochemical processes for carbonated water injection in carbonate rocks. Journal of Petroleum Science and Engineering 181, 106188. carbonated water injection and CO2-WAG scenarios for enhanced oil recovery, dynamic transfer of CO2 from aqueous phase into resident oil can cause complex pH variations, which can affect mineral dissolution around wellbore and precipitation in reservoir. Also, transfer of CO2 from carbonated water into live oil can liberate light components of the oil, which would create gas phase in-situ. In this investigation, a novel methodology was developed to numerically simulate these complex processes in an integrated approach. This study could present one step closer to realistic evaluations of dynamic CO2 transfer from carbonated water to resident oil and consequent interactions with the reactive minerals in a carbonate reservoir.Taking account of the data of coreflood experiments performed on a carbonate rock under 3100 psi and 100?°C, profiles of ionic concentration of produced brine and rock weight during carbonated water injection into a dry core (in the absence of oil) were history-matched to tune reaction parameters. Calcite reaction parameters (surface area and activation energy) were tuned to match profile of concentration of Ca++. Also, for additional oil recovery and dP profiles, secondary and tertiary carbonated water injection experiments were matched simultaneously to obtain relative permeability curves and CO2 mass transfer parameters. This new approach is called co-history-matching. Using the tuned parameters in a radial sector model, a series of simulations was performed to analyse change in rock porosity and enhanced oil recovery for large scales for carbonated water injection. Results of the large-scale model have demonstrated that minerals dissolution takes place mostly in vicinity of the injection wellbore. However, the simulation results demonstrated that injection of short cycle of carbonated water followed by plain water would alleviate the dissolution issue, while significant additional oil recovery is achieved.Mailloux, B.J., Kim, C., Kichuk, T., Nguyen, K., Precht, C., Wang, S., Jewell, T.N.M., Karaoz, U., Brodie, E.L., Williams, K.H., Beller, H.R., Buchholz, B.A., 2019. Paired RNA radiocarbon and sequencing analyses indicate the importance of autotrophy in a shallow alluvial aquifer. Scientific Reports 9, 10370. the carbon sources for active microbial populations in the subsurface is a challenging but highly informative component of subsurface microbial ecology. This work developed a method to provide ecological insights into groundwater microbial communities by characterizing community RNA through its radiocarbon and ribosomal RNA (rRNA) signatures. RNA was chosen as the biomolecule of interest because rRNA constitutes the majority of RNA in prokaryotes, represents recently active organisms, and yields detailed taxonomic information. The method was applied to a groundwater filter collected from a shallow alluvial aquifer in Colorado. RNA was extracted, radiometrically dated, and the 16S rRNA was analyzed by RNA-Seq. The RNA had a radiocarbon signature (Δ14C) of ?193.4?±?5.6‰. Comparison of the RNA radiocarbon signature to those of potential carbon pools in the aquifer indicated that at least 51% of the RNA was derived from autotrophy, in close agreement with the RNA-Seq data, which documented the prevalence of autotrophic taxa, such as Thiobacillus and Gallionellaceae. Overall, this hybrid method for RNA analysis provided cultivation-independent information on the in-situ carbon sources of active subsurface microbes and reinforced the importance of autotrophy and the preferential utilization of dissolved over sedimentary organic matter in alluvial aquifers.Mamonov, A., Kvandal, O.A., Strand, S., Puntervold, T., 2019. Adsorption of polar organic components onto sandstone rock minerals and its effect on wettability and enhanced oil recovery potential by smart water. Energy & Fuels 33, 5954-5960. is generally accepted that reservoir wettability is one of the most important parameters in oil recovery processes. In the published literature, it is believed that the state of reservoir wettability mainly depends on the adsorption or precipitation of oxygen and nitrogen compounds present in the heavy-end fractions of crude oil. However, the establishment of reservoir wetting is a more complex process that involves chemical interactions between all phases of the reservoir: rock mineral surfaces, formation water, and surface-active components in the crude oil. In this study, dynamic adsorption tests were performed by flooding modified crude oils with a low asphaltene content through outcrop sandstone cores. Adsorption of crude oil components was analyzed by comparing base number (BN) and acid number (AN) of the effluent oil samples with the known initial BN and AN of the crude oil. The experimental results showed that crude oil bases are more active than acids toward the silicate rock mineral surfaces. Within the pore volumes flooded, it was not possible to achieve equilibrium BN values because of the continuous adsorption of basic components. Spontaneous imbibition (SI) tests showed that the core sample behaved slightly water-wet after crude oil flooding. Ion-modified smart water as an imbibition fluid in tertiary mode has previously shown potential for wettability alteration and improved oil recovery. With an increase in the amount of injected crude oil through the core, a decrease in oil recovery and a decrease in smart water-enhanced oil recovery (EOR) potential were observed. SI oil recovery results indicate reduced positive capillary forces and a change in wetting toward a less water-wet state. Thus, the chemical composition of crude oil should be considered as an important parameter for a reliable estimation of the reservoir wettability state and EOR potential by smart water injection.Manzano, E., García, A., Cantarero, S., García, D., Morgado, A., Vílchez, J.L., 2019. Molecular and isotopic analyses on prehistoric pottery from the Virués-Martínez cave (Granada, Spain). Journal of Archaeological Science: Reports 27, 101929. analysis of the organic residues in archaeological pottery usually involves the use chromatography and mass spectrometry techniques. The identification of organic compounds processed in archaeological vessels, which generally degrade over archaeological timescales, provides insights about their origin and uses of the vessels. This paper provides an advance of archaeometric characterization of the organic residues in seventeen pottery vessels from the end of the 4th millennium BCE found in the Virués-Martínez cave (Granada, Spain), using gas chromatography–mass spectrometry (GC–MS), gas chromatography-isotope ratio mass spectrometry (GC-C-IRMS), and ultra-performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS). To our knowledge this is the first study on the use of UPLC-HRMS on archaeological residues. Despite the fact that the identification of plant remains continues to be elusive, this study demonstrates the potential usefulness of UPLC-HRMS technique to study the polar fraction of plant residues, thus allowing us to formulate more specific hypotheses about the vegetal compounds that have survived in association with the pottery vessels (erucamide, matricarin, piptamine, piceatannol). Our results indicate that the occupants of the cave used the vessels to process plant materials and also degraded animal fats (ruminant fat) and it is very likely that the vessels were used for a variety of purposes, with accumulation of by-products over time, and were not made exclusively for funerary practices. The δ13C values C16:0 and C18:0 fatty acids obtained open a debate on the consumption of dairy compounds in the Iberian Peninsula during the end of the Neolithic and beginning of the Copper Age.Markolefa, I., Lambrou, G.I., 2019. The role of autophagy during osteoclastogenesis under microgravity conditions. International Journal of Astrobiology 18, 384-390. represents a rather hostile environment for the human body, with the bone loss being one of the most important consequences. Autophagy is a complex cellular process contributing to several cellular processes including recycling, nutrition, apoptosis and response to stressful environments. Recent reports have indicated that autophagy is a process that increases under microgravity conditions. In particular, this was shown to be true in skeletal cells such as the osteoclasts. Suppression of autophagy results in downregulation of osteoclastogenesis, making autophagy a quite tempting therapeutic target for preventing bone loss during space flights. The present work attempts to review the literature on the topic of autophagy role in osteoclastogenesis under microgravity conditions.Marshall, I.P.G., Ren, G., Jaussi, M., Lomstein, B.A., J?rgensen, B.B., R?y, H., Kjeldsen, K.U., 2019. Environmental filtering determines family-level structure of sulfate-reducing microbial communities in subsurface marine sediments. The ISME Journal 13, 1920-1932. work has shown that subsurface microbial communities assemble by selective survival of surface community members during sediment burial, but it remains unclear to what extent the compositions of the subsurface communities are a product of their founding population at the sediment surface or of the changing geochemical conditions during burial. Here we investigate this question for communities of sulfate-reducing microorganisms (SRMs). We collected marine sediment samples from the upper 3–5?m at four geochemically contrasting sites in the Skagerrak and Baltic Sea and measured SRM abundance (quantitative PCR of dsrB), metabolic activity (radiotracer rate measurements), and community composition (Illumina sequencing of dsrB amplicons). These data showed that SRM abundance, richness, and phylogenetic clustering as determined by the nearest taxon index peaked below the bioturbation zone and above the depth of sulfate depletion. Minimum cell-specific rates of sulfate reduction did not vary substantially between sites. SRM communities at different sites were best distinguished based on their composition of amplicon sequence variants (ASVs), while communities in different geochemical zones were best distinguished based on their composition of SRM families. This demonstrates environmental filtering of SRM communities in sediment while a site-specific fingerprint of the founding community is retained.Martin, C., Ménot, G., Thouveny, N., Davtian, N., Andrieu-Ponel, V., Reille, M., Bard, E., 2019. Impact of human activities and vegetation changes on the tetraether sources in Lake St Front (Massif Central, France). Organic Geochemistry 135, 38-52. distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs) has been shown to correlate with mean annual air temperature and is increasingly used for paleoclimate reconstructions, in particular in lakes. Numerous studies have reported in situ production of brGDGTs in lakes. These brGDGTs have different distributions compared with those produced in soils and their mixing hampers paleoclimate reconstructions. Very few tools exist to determine brGDGT sources in the present and to trace their changes in the past linked with environmental changes of climatic or anthropogenic origin. While human activities are known to affect both soil and aquatic ecosystems, particularly bacterial communities, the specific impacts on brGDGT distributions are poorly investigated. High resolution analyses of brGDGTs were carried out on Holocene sediments and catchment soils of Lake St Front (Massif Central, France) in association with sedimentological, palynological, and geochemical analyses. Comparison of brGDGT distributions in sediments and soils revealed their mixed origin. For the first time, we tested the reliability of the ΣIIIa/ΣIIa ratio in lakes which indicated a gradual shift from aquatic to terrigenous brGDGT sources over the Holocene. This shift was supported by sedimentological and geochemical indices. Three events with a high proportion of terrigenous brGDGTs (6–5.5, 2.8–2.5, and 2–0.2 kyr cal BP) coincide with changes in vegetation in the catchment area, driven by climate and/or human activities. This suggests that vegetation modifications in the watershed impact brGDGT distributions and may thus bias brGDGT-based paleoclimatic reconstructions.Martiny, A.C., 2019. High proportions of bacteria are culturable across major biomes. The ISME Journal 13, 2125-2128. paradigm that only 1% of microbes are culturable has had a profound impact on our understanding of microbial ecology and is still a major motivation for mostly using molecular tools to characterize microbial communities. However, this point is often expressed vaguely, suggesting that some scientists have different interpretations of the paradigm. In addition, there have been substantial advances in cultivation techniques suggesting that this paradigm may no longer be correct. To quantify bacterial culturability across six major biomes, I found that the median 16S rRNA similarity of bacteria to known cultured relatives was 97.3?±?2.3% (s.d.). Furthermore, 52.0?±?24% of sequences and 34.9?±?23% of taxa (defined as >97% similar) had a closely related cultured relative. Thus, many cells and taxa across environments are culturable with known techniques, suggesting that the 1% paradigm is no longer correct.Marvasi, M., Cavalieri, D., Mastromei, G., Casaccia, A., Perito, B., 2019. Omics technologies for an in-depth investigation of biodeterioration of cultural heritage. International Biodeterioration & Biodegradation 144, 104736. and degradation of works of art is of great concern to preserve humankind heritage. Among categories of degradation, biodeterioration is one of the main destructive type, considering the dynamic fluctuations that microorganisms exert on the substrate. In order to understand and cope with biological damage, the use of cutting-edge molecular techniques in combined multidisciplinary approaches is nowadays in its pioneering age. We provide a review on recent applications of omics technologies (genomics, transcriptomics, proteomics, metabolomics) to advance our understanding of microbial biodeterioration of cultural heritage materials such as stone, cellulose-based substrates, parchment. The interesting picture arising from this exercise is a fingerprint of biodegradation and its biological causes, identifying metabolites and microbial communities. At the end of the review we provide an extensive perspective section suggesting future approaches and concrete tools for conservators in diagnosis and treatment of biodeterioration.McBride, E.M., Mach, P.M., Dhummakupt, E.S., Dowling, S., Carmany, D.O., Demond, P.S., Rizzo, G., Manicke, N.E., Glaros, T., 2019. Paper spray ionization: Applications and perspectives. TrAC Trends in Analytical Chemistry 118, 722-730. spray ionization has grown to become one of the most successful ambient ionization methods within the past decade. Requiring little to no sample preparation and being remarkably simple to construct, this technique has seen application in a wide number of fields. This review approaches the mechanism of how paper spray works, and seeks to better classify what it is and is not in a rapidly expanding field of ambient techniques. Additionally, many applications of the technique in clinical, forensic, environmental, and reaction monitoring regimes are explored. Finally, perspectives towards the future of how paper spray could be utilized will be expanded upon, including unexplored substrates and possibilities for the 'omics space.McConnell, J.R., Chellman, N.J., Wilson, A.I., Stohl, A., Arienzo, M.M., Eckhardt, S., Fritzsche, D., Kipfstuhl, S., Opel, T., Place, P.F., Steffensen, J.P., 2019. Pervasive Arctic lead pollution suggests substantial growth in medieval silver production modulated by plague, climate, and conflict. Proceedings of the National Academy of Sciences 116, 14910-14915.: Detailed lead pollution measurements in an array of 13 ice cores spanning nearly half the Arctic showed surprisingly similar temporal variability during the past 2 millennia until the Industrial Revolution. Lead pollution increased by 250- to 300-fold from the Early Middle Ages to the 1970s industrial peak, reflecting large-scale emissions changes from ancient European silver production, recent fossil fuel burning, and other industrial activities. Pronounced decadal-scale increases coincided with exploitation of new mining districts, technology development, and periods of economic prosperity, while decreases coincided with climate disruptions, famines, major wars, and plagues. Despite midlatitude pollution abatement policies that reduced Arctic lead pollution by >80% since the 1970s, recent levels remain 60-fold higher than at the start of the Middle Ages.Abstract: Detailed lead pollution measurements in an array of 13 ice cores spanning nearly half the Arctic showed surprisingly similar temporal variability during the past 2 millennia until the Industrial Revolution. Lead pollution increased by 250- to 300-fold from the Early Middle Ages to the 1970s industrial peak, reflecting large-scale emissions changes from ancient European silver production, recent fossil fuel burning, and other industrial activities. Pronounced decadal-scale increases coincided with exploitation of new mining districts, technology development, and periods of economic prosperity, while decreases coincided with climate disruptions, famines, major wars, and plagues. Despite midlatitude pollution abatement policies that reduced Arctic lead pollution by &amp;gt;80% since the 1970s, recent levels remain 60-fold higher than at the start of the Middle Ages.Lead pollution in Arctic ice reflects large-scale historical changes in midlatitude industrial activities such as ancient lead/silver production and recent fossil fuel burning. Here we used measurements in a broad array of 13 accurately dated ice cores from Greenland and Severnaya Zemlya to document spatial and temporal changes in Arctic lead pollution from 200 BCE to 2010 CE, with interpretation focused on 500 to 2010 CE. Atmospheric transport modeling indicates that Arctic lead pollution was primarily from European emissions before the 19th-century Industrial Revolution. Temporal variability was surprisingly similar across the large swath of the Arctic represented by the array, with 250- to 300-fold increases in lead pollution observed from the Early Middle Ages to the 1970s industrial peak. Superimposed on these exponential changes were pronounced, multiannual to multidecadal variations, marked by increases coincident with exploitation of new mining regions, improved technologies, and periods of economic prosperity; and decreases coincident with climate disruptions, famines, major wars, and plagues. Results suggest substantial overall growth in lead/silver mining and smelting emissions—and so silver production—from the Early through High Middle Ages, particularly in northern Europe, with lower growth during the Late Middle Ages into the Early Modern Period. Near the end of the second plague pandemic (1348 to ～1700 CE), lead pollution increased sharply through the Industrial Revolution. North American and European pollution abatement policies have reduced Arctic lead pollution by &amp;gt;80% since the 1970s, but recent levels remain ～60-fold higher than at the start of the Middle Ages.McMahon, P.B., Lindsey, B.D., Conlon, M.D., Hunt, A.G., Belitz, K., Jurgens, B.C., Varela, B.A., 2019. Hydrocarbons in upland groundwater, Marcellus Shale region, northeastern Pennsylvania and southern New York, U.S.A. Environmental Science & Technology 53, 8027-8035. samples from 50 domestic wells located <1 km (proximal) and >1 km (distal) from shale-gas wells in upland areas of the Marcellus Shale region were analyzed for chemical, isotopic, and groundwater-age tracers. Uplands were targeted because natural mixing with brine and hydrocarbons from deep formations is less common in those areas compared to valleys. CH4-isotope, predrill CH4-concentration, and other data indicate that one proximal sample (5% of proximal samples) contains thermogenic CH4 (2.6 mg/L) from a relatively shallow source (Catskill/Lock Haven Formations) that appears to have been mobilized by shale-gas production activities. Another proximal sample contains five other volatile hydrocarbons (0.03–0.4 μg/L), including benzene, more hydrocarbons than in any other sample. Modeled groundwater-age distributions, calibrated to?3H, SF6, and 14C concentrations, indicate that water in that sample recharged prior to shale-gas development, suggesting that land-surface releases associated with shale-gas production were not the source of those hydrocarbons, although subsurface leakage from a nearby gas well directly into the groundwater cannot be ruled out. Age distributions in the samples span ～20 to >10000 years and have implications for relating occurrences of hydrocarbons in groundwater to land-surface releases associated with recent shale-gas production and for the time required to flush contaminants from the system.Mehdi, K., Rabbani, A., Taati, F., 2019. Upper Jurassic-Lower Cretaceous source-rock evaluation and oil–source rock correlation in the Abadan Plain, southwest Iran. Geochemistry International 57, 790-804. oil samples from Lower Cretaceous Fahliyan reservoirs and 51 core and cutting samples from Upper Jurassic-Lower Cretaceous Garau Formation in Abadan Plain, Southern Iran, were analyzed using bulk property and molecular methods in order to identify their geochemical characteristics such as maturity and source depositional environment, as well as to correlate them to respective source rock(s). Rock-Eval pyrolysis and vitrinite reflectance measurements indicated that the Garau Formation, classified as a good-to-excellent source rock, the kerogen is mainly of Type II and the maturity is in peak oil generation. The crude oils of the Fahliyan reservoir are classified as light oil (API more than 35), non-biodegraded, saturate fraction, slight even/odd predominance, and front-end biased distribution in gas chromatogram. According to molecular and isotopic data, the oils were generated by a marine carbonate source rock which was deposited under the anoxic condition. Furthermore, all the studied samples reveal compositional similarity and hence can be assigned to one oil family, originating from a common source rock. Based on compositional similarities of biomarkers and isotope data in the studied crude oils and source rock, the Upper Jurassic-Lower Cretaceous Garau Formation can be regarded as the main source rock of the oils.Melosso, M., McGuire, B.A., Tamassia, F., Degli Esposti, C., Dore, L., 2019. Astronomical search of vinyl alcohol assisted by submillimeter spectroscopy. ACS Earth and Space Chemistry 3, 1189-1195. report an extension toward the submillimeter domain of the laboratory spectroscopy of the syn and anti conformers of vinyl alcohol, a species that has been detected once in the interstellar medium, in the massive star-forming region Sagittarius B2(N) (Turner, B. E.; Apponi, A. Microwave detection of interstellar vinyl alcohol, CH2CHOH. Astrophys. J. 2001, 561, L207?L210, 10.1086/324762). Spectra were recorded with high accuracy (15–20 kHz) between 245 and 310 GHz by a frequency-modulation spectrometer equipped with a pyrolysis cell. Using these spectra and the refined molecular constants, we have searched for vinyl alcohol in the publicly available spectral line surveys from the ASAI [Astrochemical Surveys at Institut de Radioastronomie Millimétrique (IRAM)] Large Project, whose source sample spans the evolutionary range of a solar-type protostar and covering 75–350 GHz (4–1 mm) in frequency. We report non-detections in all nine sources, derive upper limits to the abundance of both conformers of vinyl alcohol, and comment on possible chemical and physical explanations for the non-detections.Melott, A.L., Thomas, B.C., 2019. From cosmic explosions to terrestrial fires? The Journal of Geology 127, 475-481. lines of evidence point to one or more moderately nearby supernovae, with the strongest signal at ～2.6 Ma. We build on previous work to argue for the likelihood of cosmic ray ionization of the atmosphere and electron cascades leading to more frequent lightning and therefore an increase in nitrate deposition and wildfires. The potential exists for a large increase in the prehuman nitrate flux onto the surface, which has previously been argued to lead to CO2 drawdown and cooling of the climate. Evidence for increased wildfires exists in an increase in soot and carbon deposits over the relevant period. The wildfires would have contributed to the transition from forest to savanna in northeast Africa, long argued to have been a factor in the evolution of hominin bipedalism.Menlyadiev, M., Henderson, B.L., Zhong, F., Lin, Y., Kanik, I., 2019. Extraction of amino acids using supercritical carbon dioxide for in situ astrobiological applications. International Journal of Astrobiology 18, 102-111. detection of organic molecules that are indicative of past or present biological activity within the Solar System bodies and beyond is a key research area in astrobiology. Mars is of particular interest in this regard because of evidence of a (perhaps transient) warm and wet climate in its past. To date, space missions to Mars have primarily used pyrolysis technique to extract organic compounds from the Martian regolith, but it has not enabled a clear detection of unaltered native Martian organics. The elevated temperatures required for pyrolysis extraction can cause native Martian organics to react with perchlorate salts in the regolith, possibly resulting in the chlorohydrocarbons that have been detected by mass spectrometry, a commonly used in situ technique for space applications. Supercritical carbon dioxide (SCCO2) extraction technique is a powerful alternative to pyrolysis that may be capable of extracting and delivering unaltered native organic species to an analyser. In this study, we report the SCCO2 extraction of unaltered amino acids (AAs) with simple laboratory analyses of extracts by capillary electrophoresis laser-induced fluorescence (CE/LIF) and liquid chromatography with mass spectrometry (LC/MS) techniques. The extraction efficiencies of several representative AAs using SCCO2 with small amounts of pure water (~1–5%) as a co-solvent were determined. Glass beads were used as a model substrate to examine the effects of several experimental parameters and Johnson Space Center (JSC) Mars-1A Martian regolith simulant was used to study the effect of complex matrix on extraction efficiencies. With optimized experimental conditions (75C and 5% of water), extraction efficiencies from doped JSC Mars-1A were found to be ~40% for glycine, alanine and serine and ~10% for lysine. Extraction of native organics from undoped JSC Mars-1A suggests that SCCO2/water solvent system can extract both organics extractable with pure SCCO2 and those extractable with pure water. Additionally, species not extracted by either pure SCCO2 or pure water were extracted with SCCO2/water solvent. Despite the preliminary nature of this work, it paves the path for more comprehensive extraction studies of astrobiologically relevant samples with thorough analyses of resulting extracts.Mikutta, R., Turner, S., Schippers, A., Gentsch, N., Meyer-Stüve, S., Condron, L.M., Peltzer, D.A., Richardson, S.J., Eger, A., Hempel, G., Kaiser, K., Klotzbücher, T., Guggenberger, G., 2019. Microbial and abiotic controls on mineral-associated organic matter in soil profiles along an ecosystem gradient. Scientific Reports 9, 10294. of mineral-organic associations is a key process in the global carbon cycle. Recent concepts propose litter quality-controlled microbial assimilation and direct sorption processes as main factors in transferring carbon from plant litter into mineral-organic associations. We explored the pathways of the formation of mineral-associated organic matter (MOM) in soil profiles along a 120-ky ecosystem gradient that developed under humid climate from the retreating Franz Josef Glacier in New Zealand. We determined the stocks of particulate and mineral-associated carbon, the isotope signature and microbial decomposability of organic matter, and plant and microbial biomarkers (lignin phenols, amino sugars and acids) in MOM. Results revealed that litter quality had little effect on the accumulation of mineral-associated carbon and that plant-derived carbon bypassed microbial assimilation at all soil depths. Seemingly, MOM forms by sorption of microbial as well as plant-derived compounds to minerals. The MOM in carbon-saturated topsoil was characterized by the steady exchange of older for recent carbon, while subsoil MOM arises from retention of organic matter transported with percolating water. Overall, MOM formation is not monocausal but involves various mechanisms and processes, with reactive minerals being effective filters capable of erasing chemical differences in organic matter inputs.Milner, G.R., 2019. Early agriculture’s toll on human health. Proceedings of the National Academy of Sciences 116, 13721-13723.: It is difficult to envision a world without agriculture. However, as recently as 10 millennia ago, only in the Near East had people turned from hunting and gathering to agriculture as a means of supporting themselves. One such place was ?atalh?yük in modern-day Turkey, the subject of Larsen et al.’s (1) work reported in PNAS (Fig. 1). Several more millennia would pass before a reliance on domesticated plants and animals became commonplace in both the Old and New Worlds.Growing plants and tending animals increased yields per hectare, notably the caloric return, although doing so necessitated greater labor inputs and investments in the land itself. Settlement patterns and societal organization changed to accommodate new demands on labor, such as when planting, harvesting, and herding animals. While more food could be produced locally, much of it stored for lean seasons, agricultural economies were a mixed blessing. Diets became monotonous, and a narrower range of food courted disaster from failed harvests. More people packed together for longer periods increased the risk of disease from contaminated water, food, and soil. Social mechanisms, eventually greatly elaborated, developed to adjudicate disputes, dampening tensions that could tear communities apart. People had to defend themselves, their land, and stored food from neighboring groups because it was no longer easy to move away from sources of conflict. Variation in land quality and labor availability contributed to greater inequities among social groups than had ever existed before.It is also widely accepted that agriculture exacted a steep price in human health, an idea that had its origin in separate research efforts decades ago. In the 1960s, studies of societies that pursued traditional ways … Min, D.W., Kim, K., Lui, K.H., Kim, B., Kim, S., Cho, J., Choi, W., 2019. Abiotic formation of humic-like substances through freezing-accelerated reaction of phenolic compounds and nitrite. Environmental Science & Technology 53, 7410-7418. previously unknown abiotic humification pathway which is highly accelerated in frozen solution containing phenolic compounds and nitrite was investigated and proposed. The production of humic-like acids (HLA) and fulvic-like acids (FLA) was observed in the frozen solution (?20 °C) whereas it was negligible in aqueous solution (20 °C). Inorganic nitrogen was transformed into organic nitrogen during the humification process. Mass spectrometry (MS) and elemental analyses, including pyrolysis-GC/MS and FT-ion cyclotron resonance/MS, showed that humification products (HLA and FLA) have chemical structures and compositions similar to nature humic substances. The enhanced humification reaction could be attributed to the freeze-concentration effect, whereby nitrite ions in the unfrozen grain boundary region are transformed into nitrosonium ions which oxidize phenols to phenolic radicals. Confocal Raman microscopy confirmed that catechol and nitrite ions are preferentially concentrated at the ice grain boundary and electron paramagnetic resonance spectroscopic analysis of catechol/nitrite solution detected the phenolic radicals only in frozen solution, not in aqueous solution. The freezing-induced generation of phenolic radicals should lead to the formation of humic-like substances through polymerization. This study identifies and proposes a new humic formation pathway that might work as a model abiotic “bottom-up” mechanism in frozen environmental conditions.Mitchell, J.M., Flight, R.M., Moseley, H.N.B., 2019. Small molecule isotope resolved formula enumeration: A methodology for assigning isotopologues and metabolite formulas in Fourier transform mass spectra. Analytical Chemistry 91, 8933-8940. in Fourier transform mass spectrometry (FT-MS) enable increasingly more complex experiments in the field of metabolomics. What is directly detected in FT-MS spectra are spectral features (peaks) that correspond to sets of adducted and charged forms of specific molecules in the sample. The robust assignment of these features is an essential step for MS-based metabolomics experiments, but the sheer complexity of what is detected and a variety of analytically introduced variance, errors, and artifacts has hindered the systematic analysis of complex patterns of observed peaks with respect to isotope content. We have developed a method called SMIRFE that detects small biomolecules and determines their elemental molecular formula (EMF) using detected sets of isotopologue peaks sharing the same EMF. SMIRFE does not use a database of known metabolite formulas; instead a nearly comprehensive search space of all isotopologues within a mass range is constructed and used for assignment. This search space can be tailored for different isotope labeling patterns expected in different stable isotope tracing experiments. Using consumer-level computing equipment, a large search space of 2000 Da was constructed, and assignment performance was evaluated and validated using verified assignments on a pair of peak lists derived from spectra containing unlabeled and 15N-labeled versions of amino acids derivatized using ethylchloroformate. SMIRFE identified 18 of 18 predicted derivatized EMFs, and each assignment was evaluated statistically and assigned an e-value representing the probability to occur by chance.Moorman, S.Y., Quarles, B.L., Wang, Z., Cuntz, M., 2019. The habitable zone of Kepler-16: impact of binarity and climate models. International Journal of Astrobiology 18, 79-89. continue to investigate the binary system Kepler-16, consisting of a K-type main-sequence star, a red dwarf and a circumbinary Saturnian planet. As part of our study, we describe the system's habitable zone based on different climate models. We also report on stability investigations for possible Earth-mass Trojans while expanding a previous study by B. L. Quarles and collaborators given in 2012. For the climate models, we carefully consider the relevance of the system's parameters. Furthermore, we pursue new stability simulations for the Earth-mass objects starting along the orbit of Kepler-16b. The eccentricity distribution as obtained prefers values close to circular, whereas the inclination distribution remains flat. The stable solutions are distributed near the co-orbital Lagrangian points, thus enhancing the plausibility that Earth-mass Trojans might be able to exist in the Kepler-16(AB) system.Morgan-Sagastume, F., Jacobsson, S., Olsson, L.E., Carlsson, M., Gyllenhammar, M., Sárvári Horváth, I., 2019. Anaerobic treatment of oil-contaminated wastewater with methane production using anaerobic moving bed biofilm reactors. Water Research 163, 114851. wastewaters are generally treated by a combination of physico-chemical and biological methods. Interest in the anaerobic treatment of oily wastewaters has increased since it complements aerobic treatment and produces energy in the form of methane. The objectives of this study were to characterise the anaerobic process spontaneously occurring in a full-scale storage tank at a facility treating waste oil and oil-contaminated effluents, and to evaluate the applicability of an anaerobic moving bed biofilm reactor (AnMBBR) and an anaerobic contact reactor (ACR) for treating the oil contaminated wastewater feeding the storage tank. Three lab-scale reactors were operated in parallel over 465 days: one mesophilic and one thermophilic AnMBBR, and one thermophilic ACR. The wastewater had a high strength with an average chemical oxygen demand (COD) of 36?g/L with a soluble fraction of 80%. The BOD7/COD ratios varied between 0.1 and 0.5, indicating low aerobic degradability. However, biomethane potential tests indicated some level of anaerobic degradability with methane yields between 150 and 200 NmL/gCOD. The full-scale storage tank operated at low organic loading rates (0.35–0.43 kgCOD/m3d), and long hydraulic retention times (HRT?=?83–104?d). In comparison, the AnMBBRs achieved similar COD reductions (60%) as the full-scale tank but at a much shorter HRT of 30?d. Similar efficiency could only be reached at longer HRTs (43?d) in the ACR due to low biomass levels resulting from poor sludge settleability. The methane yield was higher (210 NmLCH4/COD removed) in the AnMBBR operated at 37?°C, compared to the other reactors working at 50?°C (180 NmLCH4/COD removed). This reactor also maintained a higher COD removal (67%) at an increased OLR of 1.1 kgCOD/m3d than the AnMBBR at 50?°C. The microbial composition of the biomass from the full-scale tank and the laboratory reactors provided evidence for the conversion of oil-contaminated wastewater into methane with a relatively high abundance of hydrogenotrophic methanogens.Moser, D.E., Arcuri, G.A., Reinhard, D.A., White, L.F., Darling, J.R., Barker, I.R., Larson, D.J., Irving, A.J., McCubbin, F.M., Tait, K.T., Roszjar, J., Wittmann, A., Davis, C., 2019. Decline of giant impacts on Mars by 4.48 billion years ago and an early opportunity for habitability. Nature Geoscience 12, 522-527. timing of the wane in heavy meteorite bombardment of the inner planets is debated. Its timing determines the onset of crustal conditions consistently below the thermal and shock pressure limits for microbiota survival, and so bounds the occurrence of conditions that allow planets to be habitable. Here we determine this timing for Mars by examining the metamorphic histories of the oldest known Martian minerals, 4.476–4.429-Gyr-old zircon and baddeleyite grains in meteorites derived from the southern highlands. We use electron microscopy and atom probe tomography to show that none of these grains were exposed to the life-limiting shock pressure of 78 GPa. 97% of the grains exhibit weak-to-no shock metamorphic features and no thermal overprints from shock-induced melting. By contrast, about 80% of the studied grains from bombarded crust on Earth and the Moon show such features. The giant impact proposed to have created Mars’ hemispheric dichotomy must, therefore, have taken place more than 4.48?Gyr ago, with no later cataclysmic bombardments. Considering thermal habitability models, we conclude that portions of Mars’ crust reached habitable pressures and temperatures by 4.2?Gyr ago, the onset of the Martian ‘wet’ period, about 0.5?Gyr earlier than the earliest known record of life on Earth. Early abiogenesis by 4.2?Gyr ago, is now tenable for both planets.Moser, S., Pichler, H., 2019. Identifying and engineering the ideal microbial terpenoid production host. Applied Microbiology and Biotechnology 103, 5501-5516. than 70,000 different terpenoid structures are known so far; many of them offer highly interesting applications as pharmaceuticals, flavors and fragrances, or biofuels. Extraction of these compounds from their natural sources or chemical synthesis is—in many cases—technically challenging with low or moderate yields while wasting valuable resources. Microbial production of terpenoids offers a sustainable and environment-friendly alternative starting from simple carbon sources and, frequently, safeguards high product specificity. Here, we provide an overview on employing recombinant bacteria and yeasts for heterologous de novo production of terpenoids. Currently, Escherichia coli and Saccharomyces cerevisiae are the two best-established production hosts for terpenoids. An increasing number of studies have been successful in engineering alternative microorganisms for terpenoid biosynthesis, which we intend to highlight in this review. Moreover, we discuss the specific engineering challenges as well as recent advances for microbial production of different classes of terpenoids. Rationalizing the current stages of development for different terpenoid production hosts as well as future prospects shall provide a valuable decision basis for the selection and engineering of the cell factory(ies) for industrial production of terpenoid target molecules.Moulian, R., Sama, S.G., Garnier, C., Mounicou, S., Enrico, M., Jaurand, X., Lobinski, R., Giusti, P., Bouyssiere, B., Barrère-Mangote, C., 2019. Speciation of metals in asphaltenes by high-performance thin-layer chromatography and laser ablation inductively coupled plasma-mass spectrometry. Energy & Fuels 33, 6060-6068. are considered to be the most problematic components of heavy oils because they can self-aggregate which leads to precipitation and causes various problems during oil recovery, transportation, and refining. The contribution of the porphyrins present in asphaltenes to the aggregation was previously studied by gel permeation chromatography inductively coupled plasma-mass spectrometry (GPC-ICP MS). The molecular weight of asphaltene aggregates was shown to be increased by free metal-containing porphyrins (corresponding to the lower molecular weight fraction) interacting with the aggregate’s surfaces by weak forces. The characterization of free porphyrins within the asphaltenes is therefore for the understanding of the mechanism of the aggregation, coprecipitation, and demetalation processes. Here, we developed a method for the separation of free porphyrins from asphaltenes on the basis of their polarity using high-performance thin-layer chromatography (HPTLC). This technique, using disposable plates, is particularly well suited for asphaltene analysis since it eliminates the risk of clogging typical of column chromatography. Cellulose plates were used in this study. The lower polarity of their hydroxyl groups limit the irreversible adsorption and improves the detection limit by the ICP-MS. Two well-separated peaks were obtained from purified asphaltene (Asphaltene 2017; Asphaltene Characterization Interlaboratory Study for PetroPhase 2017. In Proceedings of the 18th International Conference on Pretroleum Phase Behavior and Fouling, Le Havre, France, June 11–15, 2017; Total, the University of Pau, and the University of Rouen-Normandy: Le Havre, France, 2017.) and its corresponding whole crude oil and C5 and C7 fractions. The distribution of vanadium due to migration was determined by laser ablation (LA) ICP MS. The eluted fraction contained the free porphyrins, whereas the major fraction did not migrate and corresponded to trapped porphyrins. A comparison with the signal obtained by UV densitometry allowed the ratio between the inorganic and organic material to be measured.Müller, I.A., Rodriguez-Blanco, J.D., Storck, J.-C., do Nascimento, G.S., Bontognali, T.R.R., Vasconcelos, C., Benning, L.G., Bernasconi, S.M., 2019. Calibration of the oxygen and clumped isotope thermometers for (proto-)dolomite based on synthetic and natural carbonates. Chemical Geology 525, 1-17. is a very common carbonate mineral in ancient sediments, but is rarely found in modern environments. Because of the difficulties in precipitating dolomite in the laboratory at low temperatures, the controls on its formation are still debated after more than two centuries of research. Two important parameters to constrain the environment of dolomitization are the temperature of formation and the oxygen isotope composition of the fluid from which it precipitated. Carbonate clumped isotopes (expressed with the parameter Δ47) are increasingly becoming the method of choice to obtain this information. However, whereas many clumped isotope studies treated dolomites the same way as calcite, some recent studies observed a different phosphoric acid fractionation for Δ47 during acid digestion of dolomite compared to calcite. This causes additional uncertainties in the Δ47 temperature estimates for dolomites analyzed in different laboratories using different acid digestion temperatures.To tackle this problem we present here a (proto-)dolomite-specific Δ47-temperature calibration from 25 to 1100?°C for an acid reaction temperature of 70 °C and anchored to widely available calcite standards. For the temperature range 25 to 220?°C we obtain a linear Δ47-T relationship based on 289 individual measurements with R2 of 0.864: ?47CDES70°C=0.0428±0.0020×106T2+0.1481±0.0160Tin Kelvin When including two isotopically scrambled dolomites at 1100?°C, the best fit is obtained with a third order polynomial temperature relationship (R2?=?0.924): ‰?47CDES70°C‰=?0.0002×106T23+0.0041×106T22+0.0115×106T2+0.2218.Applying a calcite Δ47-T relationship produced under identical laboratory conditions results in 3 to 16?°C colder calculated formation temperatures for dolomites (with formation temperature from 0 to 100?°C) than using the (proto-)dolomite specific calibration presented here. For the synthetic samples formed between 70 and 220?°C we also determined the temperature dependence of the oxygen isotope fractionation relative to the water. Based on the similarity between our results and two other recent studies (Vasconcelos et al., 2005 and Horita, 2014) we propose that a combination of the three datasets represents the most robust calibration for (proto-)dolomite formed in a wide temperature range from 25 to 350?°C. 103αCaMg?carbonates?Water=2.9923±0.0557×106T2?2.3592±0.4116Because of the uncertainties in the phosphoric acid oxygen and clumped isotope fractionation for (proto-)dolomite, we promote the use of three samples that are available in large amounts as possible inter-laboratory reference material for oxygen and clumped isotope measurements. A sample of the middle Triassic San Salvatore dolomite from southern Switzerland, the NIST SRM 88b dolomite standard already reported in other Δ47 studies and a lacustrine Pliocene dolomite from La Roda (Spain).This study demonstrates the necessity to apply (proto-)dolomite specific Δ47-T relationships for accurate temperature estimates of dolomite formation, ideally done at identical acid digestion temperatures to avoid additional uncertainties introduced by acid digestion temperature corrections. In addition, the simultaneous analyses of dolomite reference material will enable a much better comparison of published dolomite clumped and oxygen isotope data amongst different laboratoriesNascimento-Dias, B.L.d., Galante, D., Oliveira, D., Anjos, M., 2019. Probing the chemical and mineralogical characteristics of the Martian meteorite NWA 7397 through μRaman and μXRF non-destructively. International Journal of Astrobiology 18, 73-78. meteorites have valuable information about past geological processes on Mars. In this particular case, the sample used was the Martian meteorite Northwest Africa (NWA) 7397. The main objective was to conduct preliminary analyses of the sample that was able to provide mineralogical characteristics in a non-destructive way. These meteorite NWA 7397 analyses were performed using two analytical techniques, μRaman and μXRF. Through the techniques used it was possible to suggest the presence of chromite, ilmenite, magnetite and forsterite minerals. These minerals seem to have a correspondence to one another in relation to the process that formed them. Thus, the information generated by these analytical techniques can contribute significantly by providing information on the history of Mars in order to have relevance to the areas of Astrobiology and Planetary Sciences.Nascimento, M.M., Olímpio da Rocha, G., Bittencourt de Andrade, J., 2019. Simple and effective dispersive micro-solid phase extraction procedure for simultaneous determination of polycyclic aromatic compounds in fresh and marine waters. Talanta 204, 776-791. this work, we developed a simple, comprehensive, and effective device and procedure for sample preparation based on dispersive micro-solid phase extraction (d-μ-SPE) for the simultaneous determination of 30 polycyclic aromatic compounds or PACs (including 16 polycyclic aromatic hydrocarbons (PAHs), 3 quinones, and 11 nitro-PAHs) in water samples. The extraction/preconcentration step was carried out in a customized glass device (20–250?mL) using C18 as the sorbent. A mini-UniPrep syringeless filter was used as a desorption device, which allowed one-step desorption, filtration, and injection. The main factors affecting the d-μ-SPE were optimized using the Doehlert design. The optimal d-μ-SPE conditions were 100?mg of C18, 32?min of extraction at 1000?rpm, and 20?min of sonication (at the desorption step). The limit of detection (LOD) for PAHs and nitro-PAHs ranged from 0.8?ng?L?1 (phenanthrene) to 1.5?ng?L?1 (indene [1,2,3-cd]pyrene) and from 300?ng?L?1 (2-nitrofluorene) to 500?ng?L?1 (2-nitrobiphenyl), respectively. For quinones, it varied from 1.12?μg?L?1 (1,4-naphthoquinone) to 1.70?μg?L?1(9,10-phenanthrenequinone). Relative recoveries ranged from 59.1% (benzo[a]pyrene) to 110% (chrysene) for most PAHs and 68.9% (2-nitrofluorene) to 124% (1-methyl-6-nitronaphthalene) for the nitro-PAHs. The recoveries for quinones ranged from 65.3% (9,10-phenanthrenequinone) to 95.3% (9,10-anthraquinone). The enrichment factor varied from 213 (Nap) to 497 (Flu), from 39 (1,4-naphthoquinone) to 254 (9,10-anthraquinone), and from 122 (2-nitrobiphenyl) to 295 (1-methyl-4-nitronaphthalene) for the PAHs, nitro-PAHs, and quinones, respectively. After validation, the procedure was successfully applied toward the determination of PACs in river and marine water samples. Low-molecular-weight PAHs were detected with high frequencies (62.5–100%) and the total PAH concentration ranged from 2.30?ng?L?1 (benzo[a]pyrene) to 1070?ng?L?1 (pyrene). Quinones were found at concentrations ranging from below the LOD to up to 19.8?μg?L?1. The proposed procedure was thus found to be comprehensive, precise, accurate, and suitable for determination of PACs in water samples.Naumkin, F., del Mazo-Sevillano, P., Aguado, A., Suleimanov, Y.V., Roncero, O., 2019. Zero- and high-pressure mechanisms in the complex forming reactions of OH with methanol and formaldehyde at low temperatures. ACS Earth and Space Chemistry 3, 1158-1169. recent ring polymer molecular dynamics study of the reactions of OH with methanol and formaldehyde at zero pressure and below 100 K has shown the formation of collision complexes with long lifetimes, longer than 100 ns for the lower temperatures studied, 20–100 K (del Mazo-Sevillano et al., 2019). These long lifetimes support the existence of multicollision events with the He buffer-gas atoms under experimental conditions, as suggested by several transition state theory studies of these reactions. In this work, we study these secondary collisions, as a dynamical approach to study pressure effects on these reactions. For this purpose, the potential energy surfaces of He with H2CO, OH, H2O, and HCO are calculated at highly accurate ab initio level. The stability of some of the complexes is studied using path integral molecular dynamics techniques, determining that OH–H2CO complexes can be formed up to 100 K or higher temperatures, whereas the weaker He–H2CO complexes dissociate at approximately 50 K. The predicted IR intensity spectra show new features which could help the identification of the OH–H2CO complex. Finally, the He–H2CO + OH and OH–H2CO + He collisions are studied using quasi-classical trajectories, finding that the cross section to produce HCO + H2O products increases with decreasing collision energy, and that it is ten times higher in the He–H2CO + OH case.Neukom, R., Barboza, L.A., Erb, M.P., Shi, F., Emile-Geay, J., Evans, M.N., Franke, J., Kaufman, D.S., Lücke, L., Rehfeld, K., Schurer, A., Zhu, F., Br?nnimann, S., Hakim, G.J., Henley, B.J., Ljungqvist, F.C., McKay, N., Valler, V., von Gunten, L., Consortium, P.k., 2019. Consistent multidecadal variability in global temperature reconstructions and simulations over the Common Era. Nature Geoscience 12, 643-649. surface temperature changes may be forced by natural as well as anthropogenic factors, or arise unforced from the climate system. Distinguishing these factors is essential for estimating sensitivity to multiple climatic forcings and the amplitude of the unforced variability. Here we present 2,000-year-long global mean temperature reconstructions using seven different statistical methods that draw from a global collection of temperature-sensitive palaeoclimate records. Our reconstructions display synchronous multidecadal temperature fluctuations that are coherent with one another and with fully forced millennial model simulations from the Coupled Model Intercomparison Project Phase 5 across the Common Era. A substantial portion of pre-industrial (1300–1800?ce) variability at multidecadal timescales is attributed to volcanic aerosol forcing. Reconstructions and simulations qualitatively agree on the amplitude of the unforced global mean multidecadal temperature variability, thereby increasing confidence in future projections of climate change on these timescales. The largest warming trends at timescales of 20?years and longer occur during the second half of the twentieth century, highlighting the unusual character of the warming in recent decades.Neukom, R., Steiger, N., Gómez-Navarro, J.J., Wang, J., Werner, J.P., 2019. No evidence for globally coherent warm and cold periods over the preindustrial Common Era. Nature 571, 550-554.’s climate history is often understood by breaking it down into constituent climatic epochs. Over the Common Era (the past 2,000 years) these epochs, such as the Little Ice Age, have been characterized as having occurred at the same time across extensive spatial scales. Although the rapid global warming seen in observations over the past 150 years does show nearly global coherence, the spatiotemporal coherence of climate epochs earlier in the Common Era has yet to be robustly tested. Here we use global palaeoclimate reconstructions for the past 2,000 years, and find no evidence for preindustrial globally coherent cold and warm epochs. In particular, we find that the coldest epoch of the last millennium—the putative Little Ice Age—is most likely to have experienced the coldest temperatures during the fifteenth century in the central and eastern Pacific Ocean, during the seventeenth century in northwestern Europe and southeastern North America, and during the mid-nineteenth century over most of the remaining regions. Furthermore, the spatial coherence that does exist over the preindustrial Common Era is consistent with the spatial coherence of stochastic climatic variability. This lack of spatiotemporal coherence indicates that preindustrial forcing was not sufficient to produce globally synchronous extreme temperatures at multidecadal and centennial timescales. By contrast, we find that the warmest period of the past two millennia occurred during the twentieth century for more than 98 per cent of the globe. This provides strong evidence that anthropogenic global warming is not only unparalleled in terms of absolute temperatures5, but also unprecedented in spatial consistency within the context of the past 2,000 years.Ning, C., Gao, Y., Zhang, H., Yu, H., Wang, L., Geng, N., Cao, R., Chen, J., 2019. Molecular characterization of dissolved organic matters in winter atmospheric fine particulate matters (PM2.5) from a coastal city of northeast China. Science of The Total Environment 689, 312-321. organic matters (DOMs) in fine particulate matters (PM2.5) play a crucial role in global climate change and carbon cycle. However, the chemical components of DOMs are poorly understood due to its ultra-complexity. In this study, DOMs in atmospheric PM2.5 collected during the heating period in coastal city Dalian were analyzed with ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometer, and the molecular composition was characterized. A large number of monoisotopic molecular formulas were assigned to DOMs, which could be classified into CHO, CHNO, CHOS, and CHNOS subgroups. A total of 4228 molecular formulas were identified in DOMs collected in hazy days, while only 2313 components were found in DOMs collected in normal days. CHO group was the dominated components in normal days, whereas CHNO group gave significantly higher contributions in hazy days. The S-containing (CHOS and CHNOS) groups posed the highest relative percentages in both normal and hazy days. In addition, potential emission sources were discussed according to the chemical component analysis. The van Krevelent diagram illustrated that lignin-like and protein/amino sugar family species were the most abundant subclasses in DOMs; and 78% and 94% of DOMs in atmospheric PM2.5 collected from Dalian could come from biogenic origins in hazy and normal days, respectively. More compounds in hazy days were derived from anthropogenic emissions.Nolte, S., Geel, C., Amann-Hildenbrand, A., Krooss, B.M., Littke, R., 2019. Petrophysical and geochemical characterization of potential unconventional gas shale reservoirs in the southern Karoo Basin, South Africa. International Journal of Coal Geology 212, 103249. Permian black shale samples from the southern Karoo Basin (South Africa) were investigated regarding their shale gas generation potential, storage capacity and transport properties. Samples originate from a 671?m deep borehole (KZF-1), comprising the Collingham, Whitehill and Prince Albert Formations of the lower Ecca Group (Karoo Supergroup).Based on organic geochemical analyses (TOC, TS, Rock-Eval pyrolysis and vitrinite reflectance), the Whitehill Formation was deposited under anoxic marine depositional conditions and has reached high thermal maturity. The Collingham and Prince Albert Formation were deposited under suboxic to oxic conditions. The amount of total organic carbon (TOC) across all formations ranges between 0.5 and 6.1 wt.-%, and was highest for the Whitehill Formation samples. The organic matter in the different lithologies are highly overmature with vitrinite reflectance values around 4.0% VRr, and almost absent Rock-Eval S1 and S2 peaks. Peak gas generation probably occurred due to tectono-metamorphic overprinting during the Cape Orogeny (240–270?Ma).Permeability ranges from 10?22 to 10?19?m2 (1–100 nDarcy) and is lowest for the Whitehill and Prince Albert Formation. Porosity at ambient stress ranges from 4.1 to 6.3% and is highest within the Whitehill Formation. Neither permeability nor porosity show significant dependence upon induced stress. Excess sorption capacity is highest for the Whitehill Formation, nexcess10MPa ranging from 0.079 to 0.172?mmol/g. For the depth interval investigated here (671?m), the estimated total gas storage capacity (sum of free and adsorbed gas phase) of the Whitehill Formation is approximately 400 to 465?mol CH4 per m3 rock. Using a simple one-dimensional diffusion model, we calculated the potentially remaining stored amount of gas. In a modelled best-case scenario, it is assumed that dissipation of the gas only occurs through the side boundaries (fractured dykes system) whereas top and bottom are assumed to act as perfect seals. Assuming a fracture distance of 1000?m, the model predicts complete gas dissipation to take place within a period of 10?2 to 102?Ma. Regarding the peak gas generation at 240–270?Ma, the remaining shale gas potential is therefore considered extremely low.Nordam, T., Nepstad, R., Litzler, E., R?hrs, J., 2019. On the use of random walk schemes in oil spill modelling. Marine Pollution Bulletin 146, 631-638. oil spill models, vertical mixing due to turbulence is commonly modelled by random walk. If the eddy diffusivity varies with depth, failing to take the derivative of the diffusivity into account in the random walk scheme will lead to incorrect results. Depending on the diffusivity profile, the result may be either over- or underprediction of the amount of surfaced oil. The importance of using consistent random walk schemes has been known for decades in, e.g., the plankton modelling community. However, it appears not to be common knowledge in the oil spill community, with inconsistent random walk schemes appearing even in recent publications. We demonstrate and quantify the error due to inconsistent random walk, using a simplified oil spill model, and two different diffusivity profiles. In the two cases considered, a commonly used inconsistent scheme predicts respectively 54% and 202% the amount of surface oil, compared to a consistent scheme.Nunome, Y., Kodama, K., Ueki, Y., Yoshiie, R., Naruse, I., Wagatsuma, K., 2019. Direct analysis of saturated hydrocarbons using glow discharge plasma ionization source for mass spectrometry. Talanta 204, 310-319. ionization source based on glow discharge plasma using ambient air is driven by a pulsed direct-current voltage for soft plasma ionization (SPI). The novelty of this work is that molecular ions [M+13]+ related to the analyte species (M), which may be formed by numerous oxidation, can be dominantly detected as a base peak with little or no fragmentation of them in an air plasma at a pressure of several kPa. The unique ion [M+13]+ was assigned to the oxidation product, [M+O?3H]+, which was confirmed as a deuterated ion [M+O?3D]+ ([M+10]+) by using a deuterated solvent. The ionization reactions were suggested that the product ion [M+O?3H]+ may arise from hydride abstraction reaction of M with O2+?, dehydrogenation reaction of [M?H]+? and subsequently oxidation reaction of [M?3H]+ with O3. n-Alkane mixtures was also measured to evaluate the intermolecular interaction in this system. The limits of detection (LOD) were in the range of 0.126–1.68 ppmv and the relative standard deviation (RSD) for repeatability was approximately 10.0% at the lowest concentration. To our knowledge, this is the first report demonstrating that the spectrum pattern of saturated hydrocarbons could be directly determined without any complicated fragmentation.Nürenberg, G., Kunkel, U., Wick, A., Fal?s, P., Joss, A., Ternes, T.A., 2019. Nontarget analysis: A new tool for the evaluation of wastewater processes. Water Research 163, 114842. to determine the removal efficiency of micropollutants in wastewater treatment plants (WWTPs) are widely discussed. Especially the evaluation of the potential benefit of further advanced treatment steps such as an additional tertiary treatment based on ozonation or activated carbon have come into focus. Such evaluation strategies are often based on the removal behavior of known micropollutants via target or suspected analysis. The utilization of nontarget analysis is considered to lead to a more comprehensive picture as also unknown or not expected micropollutants are analyzed. Here, the results of an evaluation via target and nontarget analysis were compared for biological treatment (BT) processes of eleven full-scale WWTPs and three different post-treatments (PTs): one sand filter (SF) and two granular activated carbon (GAC) filters. The similarity of the determined removals from target and nontarget analysis of the BTs increased significantly by excluding easily degradable "features" from the nontarget evaluation. A similar ranking of the removal trends for the BTs could also be achieved by comparing this new subset of nontarget features with a set of nine readily to moderately biodegradable micropollutants. This observation suggests that a performance ranking of BTs based either on target or nontarget analysis is plausible. In contrast to the BTs, the evaluation of the three PTs revealed that the difference of feature removal between SF and the two GACs was small, but large for the target analytes with substantially higher removal effciencies for the GACs compared to the SF. In addition to the removal behavior, the nontarget analysis provided further information about the number and quantity of transformation products (TPs) in the effluent from the BTs. For all BTs more than half (55–67%) of the features detected in the effluent were not found in the influent. A comparable proportion of TPs was also detected after GAC and sand filtration due to their microbial activities.Oakes, R.L., Peck, V.L., Manno, C., Bralower, T.J., 2019. Degradation of internal organic matter is the main control on pteropod shell dissolution after death. Global Biogeochemical Cycles 33, 749-760. The potential for preservation of thecosome pteropods is thought to be largely governed by the chemical stability of their delicate aragonitic shells in seawater. However, sediment trap studies have found that significant carbonate dissolution can occur above the carbonate saturation horizon. Here we present the results from experiments conducted on two cruises to the Scotia Sea to directly test whether the breakdown of the organic pteropod body influences shell dissolution. We find that on the timescales of 3 to 13 days, the oxidation of organic matter within the shells of dead pteropods is a stronger driver of shell dissolution than the?aragonite saturation state of seawater. Three to four days after death, shells became milky white and nano?scanning electron microscope images reveal smoothing of internal surface features and increased shell porosity, both indicative of aragonite dissolution. These findings have implications for the interpretation of the condition of pteropod shells from sediment traps and the fossil record, as well as for understanding the processes controlling particulate carbonate export from the surface ocean.Ogbesejana, A.B., Zhong, N., Sonibare, O.O., 2019. The distribution and significance of dimethyldibenzothiophenes, trimethyldibenzothiophenes and benzo[b]naphthothiophenes in source rock extracts from offshore Niger Delta basin, Nigeria. Petroleum Science and Technology 37, 1978-1986. distribution of dimethyldibenzothiophenes, trimethyldibenzothiophenes and benzo[b]naphthothiophenes were investigated in rock extracts from Niger Delta, Nigeria, by gas chromatography-mass spectrometry. The dimethyldibenzothiophenes were characterized by the predominance of 4,6-dimethyldibenzothiophene and 3,6-dimethyldibenzothiophene while 2,4,6-trimethyldibenzothiophene was the dominant compound among the trimethyldibenzothiophenes. Among the benzo[b]naphthothiophenes, the abundance of benzo[b]naphtho[2,1-d]thiophene was higher than other isomers. The rock samples were found to have immature to early mature status. The dimethyl- and trimethyldibenzothiophene ratios showed good correlation with 4-/1-methyldibenzothiophen ratio, Tmax (°C) and % Ro, indicating their dependency on maturity increase. The distribution and abundance of dimethyldibenzothiophenes and trimethyldibenzothiophenes were found to be effective in determining the thermal maturity of source rock extracts in Niger Delta basin.Ogbesejana, A.B., Zhong, N., Sonibare, O.O., 2019. Occurrence and distribution of dibenzofurans and benzo[b]naphthofurans in the crude oils from the Northern and offshore Niger Delta basin, Nigeria. Petroleum Science and Technology 37, 1969-1977. occurrence and distributions of dibenzofurans (DBFs) and benzo[b]naphthofurans were investigated in crude oils from Niger Delta, Nigeria, by gas chromatography-mass spectrometry-mass spectrometry. The distribution of DBFs was characterized by the predominance of C2-dibenzofurans. 4-Methyldibenzofuran was the most abundant among the methyldibenzofurans isomers while dimethyldibenzofuran-2 (DMDBF-2), ethyldibenzofuran-1, DMDBF-3, and DMDBF-6 occurred in higher amounts when compared with other DMDBFs. Among the benzonaphthofurans, the abundance of benzo[b]naphtho[2,1-d]furan was higher than other isomers. The DBFs distributions in the oils were not affected by source facies and depositional environments. However, the DBFs concentrations increased with increasing maturity in oils from ADL and MJO oilfields.Ojeda, A.S., Phillips, E., Mancini, S.A., Lollar, B.S., 2019. Sources of uncertainty in biotransformation mechanistic interpretations and remediation studies using CSIA. Analytical Chemistry 91, 9147-9153. isotope analysis (CSIA) is a powerful tool to understand the fate of organic contaminants. Using CSIA, the isotope ratios of multiple elements (δ13C, δ2H, δ37Cl, δ15N) can be measured for a compound. A dual-isotope plot of the changes in isotope ratios between two elements produces a slope, lambda (Λ), which can be instrumental for practitioners to identify transformation mechanisms. However, practices to calculate and report Λ and related uncertainty are not universal, leading to the potential for misinterpretations. Here, the most common methods are re-evaluated to provide the basis for a more accurate best-practice representation of Λ and its uncertainty. The popular regression technique, ordinary linear regression, can introduce mathematical bias. The York method, which incorporates error in both variables, better adapts to the wide set of data conditions observed for dual-isotope data. Importantly, the existing technique of distinguishing between Λs using the 95% confidence interval alone produces inconsistent results, whereas statistical hypothesis testing provides a more robust method to differentiate Λs. The propensity for Λ to overlap for a variety of conditions and mechanisms highlights the requirement for statistical justification when comparing data sets. Findings from this study emphasize the importance of this evaluation of best practice and provide recommendations for standardizing, calculating, and interpreting dual-isotope data.Ojeda, L., Vadillo, I., Etiope, G., Benavente, J., Li?án, C., del Rosal, Y., Tapia, S.T., Morí?igo, M.?., Carrasco, F., 2019. Methane sources and sinks in karst systems: The Nerja cave and its vadose environment (Spain). Geochimica et Cosmochimica Acta 259, 302-315. caves are considered a natural sink of atmospheric methane (CH4). Studies generally focus on measuring CH4 within the cave environment, and little information is available about the factors influencing CH4 abundance, such as the surrounding vadose and saturated zones of the aquifer, inputs of carbon dioxide (CO2) – a potential precursor of CH4 – and methanotrophic bacteria, which is likely the main cause of CH4 consumption. In this paper we report the first study of CH4 budget in Nerja, one of the main karst caves in Spain, based on seasonal monitoring of CH4 and CO2 concentration and stable C isotopic ratio in the cave system, integrated with analogue data from the underlying and overlying saturated/vadose zone, and methanotrophic bacteria activity (rDNA and Polymerase Chain Reaction analyses) in cave sediments and water. The results show that the cave environment consumes, via methanotrophic activity and through γ- and α–Proteobacteria, CH4 coming from both the atmosphere and the vadose/saturated zones of the aquifer, where it is produced microbially. However, vadose zone methanogenesis may seasonally exceed the methanotrophy capacity of the cave, resulting in a net CH4 increase in it. This competition process may be an important factor limiting the sink potential of karst caves.Osselin, F., Saad, S., Nightingale, M., Hearn, G., Desaulty, A.M., Gaucher, E.C., Clarkson, C.R., Kloppmann, W., Mayer, B., 2019. Geochemical and sulfate isotopic evolution of flowback and produced waters reveals water-rock interactions following hydraulic fracturing of a tight hydrocarbon reservoir. Science of The Total Environment 687, 1389-1400. multistage hydraulic fracturing is routinely performed for the extraction of hydrocarbon resources from low permeability reservoirs, the downhole geochemical processes linked to the interaction of fracturing fluids with formation brine and reservoir mineralogy remain poorly understood. We present a geochemical dataset of flowback and produced water samples from a hydraulically fractured reservoir in the Montney Formation, Canada, analyzed for major and trace elements and stable isotopes. The dataset consists in 25 samples of flowback and produced waters from a single well, as well as produced water samples from 16 other different producing wells collected in the same field. Additionally, persulfate breaker samples as well as anhydrite and pyrite from cores were also analyzed. The objectives of this study were to understand the geochemical interactions between formation and fracturing fluids and their consequences in the context of tight gas exploitation. The analysis of this dataset allowed for a comprehensive understanding of the coupled downhole geochemical processes, linked in particular to the action of the oxidative breaker. Flowback fluid chemistries were determined to be the result of mixing of formation brine with the hydraulic fracturing fluids as well as coupled geochemical reactions with the reservoir rock such as dissolution of anhydrite and dolomite; pyrite and organic matter oxidation; and calcite, barite, celestite, iron oxides and possibly calcium sulfate scaling. In particular, excess sulfate in the collected samples was found to be mainly derived from anhydrite dissolution, and not from persulfate breaker or pyrite oxidation. The release of heavy metals from the oxidation activity of the breaker was detectable but concentrations of heavy metals in produced fluids remained below the World Health Organization guidelines for drinking water and are therefore of no concern. This is due in part to the co-precipitation of heavy metals with iron oxides and possibly sulfate minerals.Ostrander, C.M., Sahoo, S.K., Kendall, B., Jiang, G., Planavsky, N.J., Lyons, T.W., Nielsen, S.G., Owens, J.D., Gordon, G.W., Romaniello, S.J., Anbar, A.D., 2019. Multiple negative molybdenum isotope excursions in the Doushantuo Formation (South China) fingerprint complex redox-related processes in the Ediacaran Nanhua Basin. Geochimica et Cosmochimica Acta 261, 191-209. Ediacaran Doushantuo Formation offers one of the most complete and extensively studied records of end-Neoproterozoic biotic and environmental change. Here, we report multiple coeval negative molybdenum (Mo) isotope excursions (to as low as δ98MoNIST+0.25?=??2.24?±?0.10‰; 2SD) in shales from four separate sites in South China (Rongxi, Taoying, Wuhe, and Yuanjia) that preserve the Doushantuo Formation. The negative δ98Mo excursions appear coincident with previously discovered and seemingly peculiar redox-sensitive element (RSE) patterns in the same sedimentary rocks. We propose that these geochemical trends can be explained by some combination of (a) enhanced local marine oxygenation in the sedimentary basin where the Doushantuo Formation was originally deposited (the Nanhua Basin) and (b) changes in the degree of connectivity between this paleo basin and the open ocean. Enhanced local marine oxygenation, by exposing more sediments in the Nanhua basin to H2S-poor conditions, could have hindered quantitative tetrathiomolybdate formation within these sediments. Local marine oxygenation could have also stimulated the operation of a Mn oxide shuttle. Today, both of these processes are shown to promote the retention of lighter-mass Mo isotopes in sediments and also govern RSE enrichment patterns. Alternatively, or in addition, the Nanhua Basin may not have maintained an uninterrupted connection with the open ocean during the entirety of the Ediacaran Period. The negative δ98Mo excursions occur coincident with sea level highstands that could have also exposed more sediments in the basin to H2S poor conditions and/or catalyzed the operation of a local Mn oxide shuttle. When trying to infer temporal changes in ancient global ocean redox, it is important to consider the influence of sea level changes and associated variations in local depositional conditions on stratigraphic trends in RSE enrichments and isotope compositions.Ou, C., Li, C., Huang, S., Sheng, J.J., 2019. Remigration and leakage from continuous shale reservoirs: Insights from the Sichuan Basin and its periphery, China. American Association of Petroleum Geologists 103, 1925-1962. Cretaceous–to–present-day mixed carbonate–clastic deposition along the Nicaraguan platform, western Caribbean Sea, has evolved from a tectonically controlled, rifted upper Eocene shallow–to–deep-marine carbonate–siliciclastic shelf to an upper Miocene–to–present-day tectonically stable shallow-marine carbonate platform and passive margin. By integrating subsurface data of 287 two-dimensional seismic lines and 27 wells, we interpret the Cenozoic stratigraphic sequence as 3 cycles of transgression and regression beginning with an upper Eocene rhodolitic–algal carbonate shelf that interfingered with marginal siliciclastic sediments derived from exposed areas of Central America bordering the margin to the west. During the middle Eocene, a carbonate platform was established with both rimmed reefs and isolated patch reefs. A late Eocene forced regression produced widespread erosion and subaerial exposure across much of the platform and was recorded by a regional unconformity. The Oligocene–upper Miocene sedimentary record includes a southeastward prograding delta of the proto-Coco river, which drained the emergent area of what is now northern Nicaragua. The late Miocene–to–present-day period marks a period of strong subsidence with the development of small pinnacle reefs. We describe favorable petroleum system elements of the Nicaraguan platform that include (1) Eocene fossiliferous limestone source rocks documented as thermally mature in vintage exploration wells and seen as active gas chimneys emanating from inferred carbonate reservoirs; (2) upper–to–middle Eocene reservoirs in patch and pinnacle reefs, middle Eocene calcareous slumps, and Oligocene fluvial-deltaic facies documented in wells; and (3) regional seal intervals that consist of both regional unconformities and Eocene–Oligocene intraformational shale.Ouknine, L., Khiri, F., Ibhi, A., Heikal, M.T.S., Saint-Gerant, T., Medjkane, M., 2019. Insight into African meteorite finds: Typology, mass distribution and weathering process. Journal of African Earth Sciences 158, 103551. is a favorable site for meteorites recovery in which the total number of meteorites represents more than 1/6 of all extra-terrestrial rocks recovered from the entire world. This work studies the classification of the African meteorite finds, their masses’ distribution and their alteration grades to verify some factors influencing the weathering processes. The African population comprises an abundance of stony meteorites with high percentages of rare meteorites of the world collection: Martian meteorites (62%), Ureilites (51%), Rumuruti (59%), Lunar (47%), and HED (46%). Furthermore, throughout the last two decades, the authors noted an important increase of achondrite meteorites compared to the Australian and Antarctic collections. The mass distribution of African population shows that most of the recoveries (72%) have masses more than 100?g. It peaks at about 1?kg, compared to about 0.1?kg for the Australian collection and 0.01?kg for the Antarctic finds. On the other hand, the distribution of weathering grades (W) shows the predominant of W1 (32%) and W2 (34%) which proves a better preservation of meteorites. The factors influencing the mechanism and rate of alteration of African finds include the climate, which is the main factor, the mass, the terrestrial age and the initial porosity of the samples.Ozaki, K., Thompson, K.J., Simister, R.L., Crowe, S.A., Reinhard, C.T., 2019. Anoxygenic photosynthesis and the delayed oxygenation of Earth’s atmosphere. Nature Communications 10, 3026. emergence of oxygenic photosynthesis created a new niche with dramatic potential to transform energy flow through Earth’s biosphere. However, more primitive forms of photosynthesis that fix CO2 into biomass using electrons from reduced species like Fe(II) and H2 instead of water would have competed with Earth’s early oxygenic biosphere for essential nutrients. Here, we combine experimental microbiology, genomic analyses, and Earth system modeling to demonstrate that competition for light and nutrients in the surface ocean between oxygenic phototrophs and Fe(II)-oxidizing, anoxygenic photosynthesizers (photoferrotrophs) translates into diminished global photosynthetic O2 release when the ocean interior is Fe(II)-rich. These results provide a simple ecophysiological mechanism for inhibiting atmospheric oxygenation during Earth’s early history. We also find a novel positive feedback within the coupled C-P-O-Fe cycles that can lead to runaway planetary oxygenation as rising atmospheric pO2 sweeps the deep ocean of the ferrous iron substrate for photoferrotrophy.Pacheco-Sánchez, D., Rama-Garda, R., Marín, P., Martirani von Abercron, S.-M., Marqués, S., 2019. Occurrence and diversity of the oxidative hydroxyhydroquinone pathway for the anaerobic degradation of aromatic compounds in nitrate reducing bacteria. Environmental Microbiology Reports 11, 525-537. nitrate‐reducing betaproteobacteria Azoarcus anaerobius and Thauera aromatica AR‐1 use an oxidative mechanism to anaerobically degrade resorcinol and 3,5‐dihydroxybenzoate (3,5‐DHB), respectively, rendering hydroxyhydroquinone as intermediate. The first pathway step is performed by a DMSO‐reductase family hydroxylase. The gene clusters coding for the pathway are homologous in these strains. Only these two Rhodocyclales are known to follow this anaerobic pathway, and nothing is known about its distribution in prokaryotes. To determine the relevance and diversity of this strategy in nature, we enriched for bacteria able to oxidize resorcinol or 3,5‐DHB under denitrifying conditions. Nitrate‐reducing bacteria able to degrade these compounds were present in soil, aquifer and marine sediments. We were able to isolate a number of strains with this capacity from soil and aquifer samples. Amplicon libraries of rehL, the gene encoding the first step of this pathway, showed an overall low diversity, most sequences clustering with either pathway enzyme. Isolates belonging to the Beta‐ and Gammaproteobacteria able to grow on these substrates revealed rehL homologues only in strains belonging to Thauera and Azoarcus. Analysis of sequenced genomes in the databases detected the presence of highly similar clusters in two additional betaproteobacteria and in the gammaproteobacterium Sedimenticola selenatireducens, although anaerobic growth on a dihydroxyaromatic could only be confirmed in Thauera chlorobenzoica 3CB‐1. The presence of mobile elements in the flanking sequences of some of the clusters suggested events of horizontal gene transfer, probably contributing to expand the pathway to a broader host range within the Proteobacteria.Pajdak, A., Kudasik, M., Skoczylas, N., Wierzbicki, M., Teixeira Palla Braga, L., 2019. Studies on the competitive sorption of CO2 and CH4 on hard coal. International Journal of Greenhouse Gas Control 90, 102789. paper presents the results of studies on the competitive sorption using the gas mixtures CO2?CH4 on hard coal from a Polish coal mine. The experiments were conducted at an original research stand under isobaric conditions, for the pressure values of 1, 2, 5, 10?bar, and at the temperature of 313?K.The value of the effective diffusion coefficient De grew along with the content of CO2 in the gas mixture, while for the sample saturated with pure CO2 the value of De was higher than in the sample saturated with pure CH4 by more or less one order of magnitude. The Langmuir and Langmuir-Freundlich sorption isotherms were determined. It was observed that an increase in the sorption corresponding to the filling of monolayers in both isotherms occurred along with a growth of the CO2 concentration in the gas mixture. The total pore volume increased by 19.0–29.7% in a sample saturated with pure CO2 as compared to a sample saturated with pure CH4. Pore distribution was similar. At the same time, in the sample saturated with CO2, the pore volume was higher than in the case of other samples for almost entire diameter range.Palacio Lozano, D.C., Gavard, R., Arenas-Diaz, J.P., Thomas, M.J., Stranz, D.D., Mejía-Ospino, E., Guzman, A., Spencer, S.E.F., Rossell, D., Barrow, M.P., 2019. Pushing the analytical limits: new insights into complex mixtures using mass spectra segments of constant ultrahigh resolving power. Chemical Science 10, 6966-6978. new strategy has been developed for characterization of the most challenging complex mixtures to date, using a combination of custom-designed experiments and a new data pre-processing algorithm. In contrast to traditional methods, the approach enables operation of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with constant ultrahigh resolution at hitherto inaccessible levels (approximately 3 million FWHM, independent of m/z). The approach, referred to as OCULAR, makes it possible to analyze samples that were previously too complex, even for high field FT-ICR MS instrumentation. Previous FT-ICR MS studies have typically spanned a broad mass range with decreasing resolving power (inversely proportional to m/z) or have used a single, very narrow m/z range to produce data of enhanced resolving power; both methods are of limited effectiveness for complex mixtures spanning a broad mass range, however. To illustrate the enhanced performance due to OCULAR, we show how a record number of unique molecular formulae (244?779 elemental compositions) can be assigned in a single, non-distillable petroleum fraction without the aid of chromatography or dissociation (MS/MS) experiments. The method is equally applicable to other areas of research, can be used with both high field and low field FT-ICR MS instruments to enhance their performance, and represents a step-change in the ability to analyze highly complex samples.Pan, H., Li, H., Chen, J., Zhang, Y., Liu, X., Cai, S., Cao, C., 2019. Evaluation of gas hydrate resources using hydrate morphology-dependent rock physics templates. Journal of Petroleum Science and Engineering 182, 106268. hydrates often exhibit several microscopic morphologies within the host sediments, which subsequently affect their elastic responses. Hence, good knowledge of hydrate morphology is essential for better understanding elastic responses of gas hydrate reservoirs and accurately estimating hydrate saturation. To detect possible hydrate morphology and quantify the hydrate saturation and other reservoir parameters (e.g., free gas saturation, porosity, clay content) directly from well logs or seismic data, we have developed a new rock physics inversion scheme based on two types of templates honoring the hydrate morphology. Through analysis of the developed rock physics templates, we found that gas hydrate reservoirs have different elastic behaviors for different hydrate morphologies. Ignoring the impact of hydrate morphology is insufficient in modeling the elastic properties of hydrate-bearing sediments and predicting hydrate saturation. Results of Mount Elbert test well at North Slope of Alaska show that hydrates are mainly presented as pore-filling form and the reservoir parameters estimated from 3D elastic template inversion are comparable to the references derived from core data or other well logging interpretations. Based on the attribute template inversion scheme, the results suggest that hydrates mainly occur as matrix-supporting or matrix-inclusion morphology and the hydrate saturation ranges from 20% to 40%, and free gas saturation varies from 0% to 10% for uniform distribution and from 10% to 35% for patchy distribution near the bottom simulating reflectors (BSR) at the Makran Accretionary Prism, Arabian Sea.Pang, W., Ye, Y., Jin, Z., 2019. Assessment of various approaches in the prediction of methane absolute adsorption in kerogen nanoporous media. Energy & Fuels 33, 6258-6263. is crucial to accurately characterize methane absolute adsorption in kerogen nanoporous media for gas-in-place evaluation and well productivity prediction. Assuming that methane forms a single-layer adsorption in kerogen nanopores, a large number of approaches have been reported to convert the experimentally measured excess adsorption to the absolute adsorption. Recently, we have shown that methane adsorption behavior depends on the pore size and may be very different from the single-layer adsorption model, such as the Langmuir model. Thus, it is necessary to explicitly consider the pore size distribution (PSD). While these conversion methods have been extensively used, their validity in the characterization of methane absolute adsorption in nanoporous materials, such as kerogen, has not been systematically assessed. As in our previous work, we used model kerogen with varying PSDs and grand canonical Monte Carlo simulations to model methane adsorption up to 500 bar to assess various commonly used methods converting excess adsorption to absolute adsorption. We find that the predetermined density methods using 373 or 424 kg/m3 may show unphysical phenomena and Langmuir as well as SDR models can largely overestimate the absolute adsorption. On the other hand, the Ono–Kondo (OK) lattice model with PSD can accurately characterize the absolute adsorption in nanoporous media. Interestingly, Langmuir and SDR models coupled with PSD can provide comparable predictions to OK with PSD. In addition, we also suggest to use the high-pressure excess adsorption data (up to 500 bar), instead of the commonly used low-pressure excess adsorption measurements (up to 150 bar). Our work also calls for the accurate characterization of PSD in nanoporous materials to obtain their absolute adsorption capacity.Pang, Y., He, Y., Chen, S., 2019. An innovative method to characterize sorption-induced kerogen swelling in organic-rich shales. Fuel 254, 115629. swelling due to the gas sorption has not been properly accounted in the organic-rich shale formations. In general, the adsorbed gas attaches on the pore surface in the kerogen and clay minerals and occupies the pore volume. Meanwhile, the absorbed gas dissolves or diffuses into the matrix (solid lattice) of kerogen, resulting in the swelling of kerogen. As a result, the increase of the adsorbed and absorbed gases leads to a reduction of the pore volume for the free gas. Thus, it is essential to appropriately characterize the kerogen swelling caused by gas sorption so that to accurately determine the nanopore structure and the gas transport behavior in shale kerogen.In this study, an innovative method is developed to evaluate the swelling behavior of kerogen ascribed to the methane sorption. The method aims at characterizing the regions of adsorbed gas, absorbed gas, and free gas in the slit-shaped nanopores in shale kerogen based on the density profile determined using the Simplified Local-Density (SLD) model. Results for Barnett and Eagle Ford shale kerogens reveal that the gas adsorption prevails when the pore pressure is less than 6?MPa, whereas the gas absorption dominates the gas sorption process when the pore pressure is larger than 6?MPa. In addition, the ratio of absorption thickness to adsorption thickness increases with the pore pressure and such ratio reaches the 34.4% and 25.4% at the pore pressure around 20?MPa for the Barnett and Eagle Ford shale kerogens, respectively. Furthermore, the bulk and pore volumetric strains of the kerogen in the Barnett and Eagle Ford shale core samples are calculated based on the swelling length of kerogen caused by the methane sorption. The calculated strains of kerogen are in line with the measured strains of the shale and coal samples published in the literature, which verifies the reliability of the proposed innovative method. Finally, the impacts of methane sorption on the surface diffusion and the gas slippage in the slit nanopores of kerogen are also discussed.The proposed method provides a practical approach to characterize the sorption-induced kerogen swelling in shales, which is difficult to measure in the laboratory. The findings of this study advance the understanding of gas sorption process and give insight into the characterization of nanopore structure and gas transport mechanism in shale kerogen.Papineau, D., De Gregorio, B.T., Sagar, J., Thorogate, R., Wang, J., Nittler, L., Kilcoyne, D.A., Marbach, H., Drost, M., Thornton, G., 2019. Fossil biomass preserved as graphitic carbon in a late Paleoproterozoic banded iron formation metamorphosed at more than 550°C. Journal of the Geological Society 176, 651. is thought to destroy microfossils, partly through devolatilization and graphitization of biogenic organic matter. However, the extent to which there is a loss of molecular, elemental and isotope signatures from biomass during high-temperature metamorphism is not clearly established. We report on graphitic structures inside and coating apatite grains from the c. 1850 Ma Michigamme silicate banded iron formation from Michigan, metamorphosed above 550°C. Traces of N, S, O, H, Ca and Fe are preserved in this graphitic carbon and X-ray spectra show traces of aliphatic groups. Graphitic carbon has an expanded lattice around 3.6 ?, forms microscopic concentrically-layered and radiating polygonal flakes and has homogeneous δ13C values around ?22‰, identical to bulk analyses. Graphitic carbon inside apatite is associated with nanometre-size ammoniated phyllosilicate. Precursors of these metamorphic minerals and graphitic carbon originated from ferruginous clay-rich sediments with biomass. We conclude that graphite coatings and inclusions in apatite grains indicate fluid remobilization during amphibolite-facies metamorphism of precursor biomass. This new evidence fills in observational gaps of metamorphosed biomass into graphite and supports the existence of biosignatures in the highly metamorphosed iron formation from the Eoarchean Akilia Association, which dates from the beginning of the sedimentary rock record.Supplementary material: Figures illustrating the petrography and analytical results are available at: , R.I., Ishii, K., Mamun, M.A.A., Miah, S., Naito, K., Mashio, A.S., Maki, T., Hasegawa, H., 2019. Arsenic biotransformation potential of six marine diatom species: effect of temperature and salinity. Scientific Reports 9, 10226. and salinity effects on marine diatom species growth has been studied extensively; however, their effect on arsenic (As) biotransformation has been imprecise. This study reports the growth, and As biotransformation and speciation patterns at various temperatures and salinities of six marine diatom species: Asteroplanus karianus, Thalassionema nitzschioides, Nitzschia longissima, Skeletonema sp., Ditylum brightwellii, and Chaetoceros didymus. The growth rate and As biotransformation potentials of these species during three weeks of culture in f/2 based medium were significantly affected by wide temperature (0–35?°C) and salinity (0.3–50‰) ranges. Growth and As biotransformation were higher at optimum temperatures of 10–25?°C, and salinity of 10–35‰, whereas growth and arsenic biotransformation were lower at <5?°C and 5‰ and >25?°C and 35‰, respectively. The results showed that As(V) to As(III) biotransformation differed significantly (p?<?0.05) between day 10 and 17. At optimum temperature and salinity levels, the cell size and As biotransformation were higher for all the species. A conceptual model on temperature and salinity effects on growth and As uptake and biotransformation mechanisms by these species has been proposed based on the findings of this study.Parkinson, C.L., 2019. A 40-y record reveals gradual Antarctic sea ice increases followed by decreases at rates far exceeding the rates seen in the Arctic. Proceedings of the National Academy of Sciences 116, 14414-14423.: A newly completed 40-y record of satellite observations is used to quantify changes in Antarctic sea ice coverage since the late 1970s. Sea ice spreads over vast areas and has major impacts on the rest of the climate system, reflecting solar radiation and restricting ocean/atmosphere exchanges. The satellite record reveals that a gradual, decades-long overall increase in Antarctic sea ice extents reversed in 2014, with subsequent rates of decrease in 2014–2017 far exceeding the more widely publicized decay rates experienced in the Arctic. The rapid decreases reduced the Antarctic sea ice extents to their lowest values in the 40-y record, both on a yearly average basis (record low in 2017) and on a monthly basis (record low in February 2017).Abstract: Following over 3 decades of gradual but uneven increases in sea ice coverage, the yearly average Antarctic sea ice extents reached a record high of 12.8 × 106 km2 in 2014, followed by a decline so precipitous that they reached their lowest value in the 40-y 1979–2018 satellite multichannel passive-microwave record, 10.7 × 106 km2, in 2017. In contrast, it took the Arctic sea ice cover a full 3 decades to register a loss that great in yearly average ice extents. Still, when considering the 40-y record as a whole, the Antarctic sea ice continues to have a positive overall trend in yearly average ice extents, although at 11,300 ± 5,300 km2?y?1, this trend is only 50% of the trend for 1979–2014, before the precipitous decline. Four of the 5 sectors into which the Antarctic sea ice cover is divided all also have 40-y positive trends that are well reduced from their 2014–2017 values. The one anomalous sector in this regard, the Bellingshausen/Amundsen Seas, has a 40-y negative trend, with the yearly average ice extents decreasing overall in the first 3 decades, reaching a minimum in 2007, and exhibiting an overall upward trend since 2007 (i.e., reflecting a reversal in the opposite direction from the other 4 sectors and the Antarctic sea ice cover as a whole).Parzanini, C., Parrish, C.C., Hamel, J.-F., Mercier, A., 2019. Reviews and syntheses: Insights into deep-sea food webs and global environmental gradients revealed by stable isotope (δ15N, δ13C) and fatty acid trophic biomarkers. Biogeosciences 16, 2837-2856. markers developed initially for food-web studies of terrestrial and shallow-water environments have only recently been applied to deep-sea ecosystems (i.e., in the early 2000s). For the first time since their implementation, this review took a close look at the existing literature in the field of deep-sea trophic ecology to synthesize current knowledge. Furthermore, it provided an opportunity for a preliminary analysis of global geographic (i.e., latitudinal, along a depth gradient) trends in the isotopic (δ15N, δ13C) and fatty acid composition of deep-sea macro- and megafauna from heterotrophic systems. Results revealed significant relationships along the latitudinal and bathymetric gradients. Deep-sea animals sampled at temperate and polar latitudes displayed lower isotopic ratios and greater proportions of essential ω3 long-chain polyunsaturated fatty acids (LC-PUFAs) than did tropical counterparts. Furthermore, δ15N and δ13C ratios as well as proportions of arachidonic acid increased with increasing depth. Since similar latitudinal trends in the isotopic and fatty acid composition were found in surface water phytoplankton and particulate organic matter, these results highlight the link across latitudes between surface primary production and deep-water communities. Because global climate change may affect quantity and quality (e.g., levels of essential ω3 PUFAs) of surface primary productivity, and by extension those of its downward flux, the dietary intake of deep-sea organisms may likely be altered. In addition, because essential ω3 PUFAs play a major role in the response to temperature variations, climate change may interfere with the ability of deep-sea species to cope with potential temperature shifts. Importantly, methodological disparities were highlighted that prevented in-depth analyses, indicating that further studies should be conducted using standardized methods in order to generate more reliable global predictions.Patterson, D.B., Braun, D.R., Allen, K., Barr, W.A., Behrensmeyer, A.K., Biernat, M., Lehmann, S.B., Maddox, T., Manthi, F.K., Merritt, S.R., Morris, S.E., O’Brien, K., Reeves, J.S., Wood, B.A., Bobe, R., 2019. Comparative isotopic evidence from East Turkana supports a dietary shift within the genus Homo. Nature Ecology & Evolution 3, 1048-1056. has been suggested that a shift in diet is one of the key adaptations that distinguishes the genus Homo from earlier hominins, but recent stable isotopic analyses of fossils attributed to Homo in the Turkana Basin show an increase in the consumption of C4 resources circa 1.65?million years ago, significantly after the earliest evidence for Homo in the eastern African fossil record. These data are consistent with ingesting more C4 plants, more animal tissues of C4 herbivores, or both, but it is also possible that this change reflects factors unrelated to changes in the palaeobiology of the genus Homo. Here we use new and published carbon and oxygen isotopic data (n?=?999) taken from large-bodied fossil mammals, and pedogenic carbonates in fossil soils, from East Turkana in northern Kenya to investigate the context of this change in the isotope signal within Homo. By targeting taxa and temporal intervals unrepresented or undersampled in previous analyses, we were able to conduct the first comprehensive analysis of the ecological context of hominin diet at East Turkana during a period crucial for detecting any dietary and related behavioural differences between early Homo (H. habilis and/or H. rudolfensis) and Homo erectus. Our analyses suggest that the genus Homo underwent a dietary shift (as indicated by δ13Cena and δ18Oena values) that is (1) unrelated to changes in the East Turkana vegetation community and (2) unlike patterns found in other East Turkana large mammals, including Paranthropus and Theropithecus. These data suggest that within the Turkana Basin a dietary shift occurred well after we see the first evidence of early Homo in the region.Perri, E., Borrelli, M., Bernasconi, M.P., Gindre-Chanu, L., Spadafora, A., Critelli, S., 2019. Microbial-dominated carbonate depositional systems: a biosedimentary and stratigraphic reconstruction in the Late Triassic of Western Tethys (northern Calabria, Italy). Facies 65, 31. northern Calabria Norian-Rhaetian carbonate platform system is characterized by three depositional units: early-middle Norian Corvino Unit (CU), middle-late Norian Vaccuta Unit (VU) and late Norian-Rhaetian Grisolia Unit (GU). The CU presents a deep barrier reef consisting of an oligotypic framebuilder community of sponges, serpulids, algae, and stromatolitic microbialites. The intra-supratidal facies mainly comprise flat to low-relief, frequently subaerial-exposed, stromatolites and thrombolites, whereas subtidal facies include high-relief stromatolites and skeletal packstones. In the outer shelf, debrites, turbidites, mudstones, and slumped layers are present. In the VU, bioclastic sand-barriers, inhabited by monospecific bivalve clusters (Isognomon exilis) and low- to high-relief small-scale stromatolites, protected a peritidal domain characterized by flat to high-relief thrombolites and stromatolites. The outer-ramp facies include laminated mudstones and tempestites interbedded with sporadic flat stromatolites. Finally, tempestites and marlstones, characterizing the GU shelf, overlie all previous shallow- to deep-water facies, testifying a terrigenous input and the end of the previous carbonate factory. The Norian oligotypic fossil associations of the CU and VU imply anoxia and eutrophy, likely due to limited water circulation, related to basin isolation from the open ocean. During the whole Norian-Rhaetian interval syn-depositional down-faulting pulses was accompanied by gradual eustatic sea-level drop, inducing episodes of isolation and opening of the basin. Tectonic pulses influenced the sequence stratigraphic architecture creating an atypical system-tracts succession characterized by retrogradation of the CU and progradation followed by retrogradation for the VU and GU.Persson, E., Capova, K.A., Li, Y., 2019. Attitudes towards the scientific search for extraterrestrial life among Swedish high school and university students. International Journal of Astrobiology 18, 280-288. aim of this study is to increase our understanding of the attitudes towards the scientific search for extraterrestrial life among high school and university students in Sweden. The most important results of the analysis are that: (a) the great majority of students believe that extraterrestrial life exists; (b) most students regard searching for extraterrestrial life to be quite important or very important; (c) very few students think that we should actively avoid searching for extraterrestrial life; (d) the most common motive for assigning a high priority to search for extraterrestrial life is that it is interesting, the most common motive for assigning a low priority is that such knowledge would not be practically useful, or that the money would be better spent elsewhere; (e) most students do not think they are very well informed regarding the search for extraterrestrial life. A higher percentage of the students who judge themselves to be well informed also believe that extraterrestrial life exists. We have also found some differences between subgroups (men/women, high school students/university students and different fields of study), but the differences are with few exceptions small in comparison with the overall trends, and they mostly differ in degree rather than direction.Peters, T., 2019. Does extraterrestrial life have intrinsic value? An exploration in responsibility ethics. International Journal of Astrobiology 18, 304-310. space explorers discover a biosphere supporting life on an off-Earth body, should they treat that life as possessing intrinsic value? This is an ethical quandary leading to a further question: how do we ground a universal moral norm to which the astroethicist can appeal? This article closely analyses various forms of responsibility ethics and finds them weak because they commit the naturalistic fallacy – that is, they ask nature to define the good. The good, however, is self-defining and not derivable from nature. Even so, a revised responsibility ethic could ground its universal norms on the fact that life and only life can experience and appreciate the good. Conclusion: living creatures possess intrinsic value both on Earth and elsewhere in the Universe.Peters, T., 2019. Does extraterrestrial life have intrinsic value? An exploration in responsibility ethics– Corrigendum. International Journal of Astrobiology 18, 391-391., C., Pegoraro, E., Bracho, R., Celis, G., Crummer, K.G., Hutchings, J.A., Hicks Pries, C.E., Mauritz, M., Natali, S.M., Salmon, V.G., Sch?del, C., Webb, E.E., Schuur, E.A.G., 2019. Direct observation of permafrost degradation and rapid soil carbon loss in tundra. Nature Geoscience 12, 627-631. suggests that 5–15% of the vast pool of soil carbon stored in northern permafrost ecosystems could be emitted as greenhouse gases by 2100 under the current path of global warming. However, direct measurements of changes in soil carbon remain scarce, largely because ground subsidence that occurs as the permafrost soils begin to thaw confounds the traditional quantification of carbon pools based on fixed depths or soil horizons. This issue is overcome when carbon is quantified in relation to a fixed ash content, which uses the relatively stable mineral component of soil as a metric for pool comparisons through time. We applied this approach to directly measure soil carbon pool changes over five years in experimentally warmed and ambient tundra ecosystems at a site in Alaska where permafrost is degrading due to climate change. We show a loss of soil carbon of 5.4% per year (95% confidence interval: 1.0, 9.5) across the site. Our results point to lateral hydrological export as a potential pathway for these surprisingly large losses. This research highlights the potential to make repeat soil carbon pool measurements at sentinel sites across the permafrost region, as this feedback to climate change may be occurring faster than previously thought.Pokharel, R., Gerrits, R., Schuessler, J.A., von Blanckenburg, F., 2019. Mechanisms of olivine dissolution by rock-inhabiting fungi explored using magnesium stable isotopes. Chemical Geology 525, 18-27. unravel the dissolution mechanisms of olivine by a rock-inhabiting fungus we determined the stable isotope ratios of Mg on solutions released in a laboratory experiment. We found that in the presence of the fungus Knufia petricola the olivine dissolution rates were about seven-fold higher (1.04?×?10?15?mol?cm?2?s?1) than those in the abiotic experiments (1.43?×?10?16?mol?cm?2?s?1) conducted under the same experimental condition (pH?6, 25?°C, 94?days). Measured element concentrations and Mg isotope ratios in the supernatant solutions in both the biotic and the abiotic experiment followed a dissolution trend in the initial phase of the experiment, characterized by non-stoichiometric release of Mg and Si and preferential release of 24Mg over 26Mg. In a later phase, the data indicates stoichiometric release of Mg and Si, as well as isotopically congruent Mg release. We attribute the initial non-stoichiometric phase to the rapid replacement of Mg2+ in the olivine with H+ along with simultaneous polymerization of Si tetrahedra, resulting in high dissolution rates, and the stoichiometric phase to be influenced by the accumulation of a Si-rich amorphous layer that slowed olivine dissolution. We attribute the accelerated dissolution of olivine during the biotic experiment to physical attachment of K. petricola to the Si-rich amorphous layer of olivine which potentially results in its direct exposure to protons released by the fungal cells. These additional protons can diffuse through the Si-rich amorphous layer into the crystalline olivine. Our results also indicate the ability of K. petricola to dissolve Fe precipitates in the Si-rich amorphous layer either by protonation, or by Fe(III) chelation with siderophores. Such dissolution of Fe precipitates increases the porosity of the Si-rich amorphous layer and hence enhances olivine dissolution. The acceleration of mineral dissolution in the presence of a rock-dissolving fungus further suggests that its presence in surficial CO2 sequestration plants may aid to accelerate CO2 binding.Polissar, P.J., Rose, C., Uno, K.T., Phelps, S.R., deMenocal, P., 2019. Synchronous rise of African C4 ecosystems 10 million years ago in the absence of aridification. Nature Geoscience 12, 657-660. expanded globally during the late Cenozoic and the development of these ecosystems shaped the evolution of many faunal groups, including our hominin ancestors. The emergence of these ecosystems has been dated in many regions, but the origins of the iconic African C4 savannah grasslands remain poorly known, as do the causal factors that led to their establishment. Here we document their origins with the distinct carbon isotope signature from the hot-, arid- and low-CO2-adapted C4 grasses that dominate modern savannahs and grasslands. We use the carbon isotope values of leaf-wax molecules in deep-sea drill cores to measure the rise of African C4 ecosystems. We also reconstruct African palaeohydroclimate change from leaf-wax hydrogen isotope values and dust deposition rates in these cores. We find that C4-dominated ecosystems expanded synchronously across Northwestern and East Africa after 10?million years ago. This was not accompanied by substantial changes in palaeohydrology or dust deposition, precluding aridification as a causal factor. The expansion of C4 grasses was coincident, however, with dramatic high-latitude cooling and increased pole–Equator temperature gradients. We suggest that declining atmospheric CO2 levels were a direct cause of the C4 grassland expansion.Pollyea, R.M., Chapman, M.C., Jayne, R.S., Wu, H., 2019. High density oilfield wastewater disposal causes deeper, stronger, and more persistent earthquakes. Nature Communications 10, 3077. wastewater disposal causes fluid pressure transients that induce earthquakes. Here we show that, in addition to pressure transients related to pumping, there are pressure transients caused by density differences between the wastewater and host rock fluids. In northern Oklahoma, this effect caused earthquakes to migrate downward at ~0.5?km per year during a period of high-rate injections. Following substantial injection rate reductions, the downward earthquake migration rate slowed to ~0.1?km per year. Our model of this scenario shows that the density-driven pressure front migrates downward at comparable rates. This effect may locally increase fluid pressure below injection wells for 10+ years after substantial injection rate reductions. We also show that in north-central Oklahoma the relative proportion of high-magnitude earthquakes increases at 8+ km depth. Thus, our study implies that, following injection rate reductions, the frequency of high-magnitude earthquakes may decay more slowly than the overall earthquake rate.Prendergast, M.E., Lipson, M., Sawchuk, E.A., Olalde, I., Ogola, C.A., Rohland, N., Sirak, K.A., Adamski, N., Bernardos, R., Broomandkhoshbacht, N., Callan, K., Culleton, B.J., Eccles, L., Harper, T.K., Lawson, A.M., Mah, M., Oppenheimer, J., Stewardson, K., Zalzala, F., Ambrose, S.H., Ayodo, G., Gates, H.L., Gidna, A.O., Katongo, M., Kwekason, A., Mabulla, A.Z.P., Mudenda, G.S., Ndiema, E.K., Nelson, C., Robertshaw, P., Kennett, D.J., Manthi, F.K., Reich, D., 2019. Ancient DNA reveals a multistep spread of the first herders into sub-Saharan Africa. Science 365, eaaw6275.: How food production first entered eastern Africa ~5000 years ago and the extent to which people moved with livestock is unclear. We present genome-wide data from 41 individuals associated with Later Stone Age, Pastoral Neolithic (PN), and Iron Age contexts in what are now Kenya and Tanzania to examine the genetic impacts of the spreads of herding and farming. Our results support a multiphase model in which admixture between northeastern African–related peoples and eastern African foragers formed multiple pastoralist groups, including a genetically homogeneous PN cluster. Additional admixture with northeastern and western African–related groups occurred by the Iron Age. These findings support several movements of food producers while rejecting models of minimal admixture with foragers and of genetic differentiation between makers of distinct PN artifacts.Editor's Summary: East African genetics and pastoralism. The origin and spread of domestic animals across the globe also affected the underlying genetic composition of human populations. In Africa, however, it has been difficult to identify the impact of interactions among migrating food producers and local hunter-gatherers. Prendergast et al. wanted to discern the timing and movement of husbandry and pastoralism and its effects on foraging communities in Africa. They sequenced 41 ancient eastern African human genomes from individuals that lived approximately 100 to 4000 years ago. Surprisingly, relatively little genetic mixture occurred at the same time as the spread of pastoralism.Structured AbstractIntroduction: Cattle, sheep, and goats appeared in eastern Africa 5000 years ago, catalyzing the spread of herding throughout sub-Saharan Africa. Archaeologists have long debated the geographic origins of eastern Africa’s first herders, the extent to which people moved with livestock, and relationships among food-producing and foraging communities. In this work, we integrate ancient DNA with archaeological, linguistic, and genetic evidence to explore how pastoralism developed within this region, establishing the roots of one of Africa’s dominant economic strategies.Rationale: Research into the spread of herding has been limited by patchy archaeological data and poorly preserved human remains. Ancient DNA has the potential to untangle patterns of movement and interaction underlying this economic and cultural transition. We generated genome-wide ancient DNA data from the remains of 41 individuals (35 directly radiocarbon dated) associated with Later Stone Age (n = 3), early pastoral and Pastoral Neolithic (n = 31), Iron Age (n = 1), and Pastoral Iron Age (n = 6) traditions in what are now Kenya and Tanzania to study how ancient individuals were related to each other and to people living today.Results: We document a multistep spread of herding and farming into eastern Africa. Ancient individuals genetically correlate with their archaeological associations: Later Stone Age individuals form part of a forager genetic cline, early pastoral and Pastoral Neolithic individuals are most closely related to present-day Afro-Asiatic speakers, and Pastoral Iron Age individuals show affinities to present-day Nilotic speakers. A child buried at an Iron Age agricultural site has shared ancestry with western Africans and Bantu speakers.We propose a four-stage model that fits the data. First, admixture in northeastern Africa created groups with approximately equal proportions of ancestry related to present-day Sudanese Nilotic speakers and groups from northern Africa and the Levant. Second, descendants of these northeastern Africans mixed with foragers in eastern Africa. Third, an additional component of Sudan-related ancestry contributed to Iron Age pastoralist groups. Fourth, western African–related ancestry, similar to that found in present-day Bantu speakers, appeared with the spread of farming.We also observe a high frequency of a Y chromosome lineage associated with the spread of pastoralism, as well as a single individual with a genetic variant conferring adult lactase persistence. We do not detect any differentiation among individuals associated with two distinctive Pastoral Neolithic artifact traditions, suggesting that these represent cultural rather than ancestral differences.Conclusion: Archaeological and now genetic evidence suggest complex spreads of herding and farming in eastern Africa involving multiple movements of ancestrally distinct peoples as well as gene flow among these groups. Models formulated on the basis of ancient DNA are a starting point for further exploration through additional archaeological, linguistic, and genetic research.Qian, C., Quan, W., Li, C., Xiang, Z., 2019. Analysis of volatile terpenoid compounds in Rhododendron species by multidimensional gas chromatography with quadrupole time-of-flight mass spectrometry. Microchemical Journal 149, 104064. this work, an efficient analytical method based on headspace solid phase microextraction (HS-SPME) and multidimensional gas chromatography coupled with simultaneous quadrupole time-of-flight mass spectrometry and flame ionization detection (MDGC-QTOFMS/FID) was established to analyze volatile terpenoids of Rhododendron. The HS-SPME method were optimized for the best extraction efficiency by using divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fibers at 70?°C equilibration temperature for 20?min, and extracted for 15?min. A total of 34 volatile terpenoid compounds were identified by NIST mass spectral match, and confirmed by accurate mass and retention index (RI). Quantitative analysis was performed with an internal standard (IS) 1,4-cineole. The relative standard deviations (RSD) of most identified compounds were <19.7% for intraday and 18.8% for interday measurements, respectively. Samples from six different Rhododendron species were analyzed, and the results indicated that monoterpenes and their oxygenated derivatives were the major components in all species of Rhododendron, including D-limonene (average 2781.69?μg/kg), followed by p-cymene (average 254.52?μg/kg), linalool (average 224.40?μg/kg), 6-methyl-5-hepten-2-one (average 150.39?μg/kg) and α-terpineol (average 140.17?μg/kg). Additionally, principal component analysis (PCA) was applied to study the detailed differences in terpenoid concentrations in different parts of Rhododendron species.Qin, M., Cao, Z., Guo, J., Huang, Y., Sun, L., Dong, L., 2019. Characteristics of shale reservoir and sweet spot identification of the Lower Cambrian Niutitang Formation in northwestern Hunan Province, China. Acta Geologica Sinica - English Edition 93, 573-587. accumulation and productivity of shale gas are mainly controlled by the characteristics of shale reservoirs; study of these characteristics forms the basis for the shale gas exploitation of the Lower Cambrian Niutitang Formation (Fm), Southern China. In this study, core observation and lithology study were conducted along with X‐ray diffraction (XRD) and electronic scanning microscopy (SEM) examinations and liquid nitrogen (N2) adsorption/desorption and CH4 isothermal adsorption experiments for several exploration wells in northwestern Hunan Province, China. The results show that one or two intervals with high‐quality source rocks (TOC>2 wt%) were deposited in the deep‐shelf facies. The source rocks, which were mainly composed of carbonaceous shales and siliceous shales, had high quartz contents (>40 wt%) and low clay mineral (<30 wt%, mainly illites) and carbonate mineral (<20 wt%) contents. The SEM observations and liquid nitrogen (N2) adsorption/desorption experiments showed that the shale is tight, and nanoscale pores and microscale fractures are well developed. BJH volume (VBJH) of shale ranged from 2.144×10–3 to 20.07×10–3 cm3/g, with an average of 11.752×10–3 cm3/g. Pores mainly consisted of opened and interconnected mesopores (2–50 nm in diameter) or macropores (>50 nm in diameter). The shale reservoir has strong adsorption capacity for CH4. The Langmuir volume (VL) varied from 1.63 to 7.39 cm3/g, with an average of 3.95 cm3/g. The characteristics of shale reservoir are controlled by several factors: (1) A deep muddy continental shelf is the most favorable environment for the development of shale reservoirs, which is controlled by the development of basic materials. (2) The storage capacity of the shale reservoir is positively related to the TOC contents and plastic minerals and negatively related to cement minerals. (3) High maturity or overmaturity leads to the growth of organic pores and microfractures, thereby improving the reservoir storage capacity. It can be deduced that the high percentage of residual gas in Niutitang Fm results from the strong reservoir storage capacity of adsorbed gas. Two layers of sweet spots with strong storage capacity of free gas, and they are characterized by the relatively high TOC contents ranging from 4 wt% to 8 wt%.Qu, Y., Tao, H., Ma, D., Wu, T., Qiu, J., 2019. Biomarker characteristics and geological significance of middle and upper Permian source rocks in the southeastern Junggar Basin. Petroleum Science and Technology 37, 2066-2080. organic carbon content (TOC), carbon isotope and biomarker analysis have been done on the source rocks from Lucaogou and Wutonggou formations in Junggar Basin, NW China. (1) the TOC values of the source rocks are more than 5%, and the kerogen types are type I1-II, and the organic matters are mainly algae and bacteria, and are in the mature stage. (2) the depositional environments of the source rocks are weak reduction-weak oxidation, and are of weakly salty water to brackish water environment.Quadra, G.R., Sobek, S., Paranaíba, J.R., Isidorova, A., Roland, F., do Vale, R., Mendon?a, R., 2019. High organic carbon burial but high potential for methane ebullition in the sediments of an Amazonian reservoir. Biogeosciences Discussions 2019, 1-25. sediments sequester significant amounts of organic carbon (OC), but at the same time, high amounts of methane (CH4) can be produced during the degradation of sediment OC. Hydropower is expanding in the Amazon basin, but the potential effects of river damming on the biogeochemistry of the Amazon river system can at present not be gauged due to a lack of studies. Here we present results from the first investigation of OC burial and CH4 concentrations in the sediments of an Amazonian reservoir. We performed sub-bottom profiling, sediment coring and sediment pore water analysis in the Curuá-Una reservoir (Amazon, Brazil) during rising and falling water periods. A mean sediment accumulation rate of 0.6?cm?yr?1 and a mean OC burial rate of 91?g?C?m?2?yr?1 were found, which is the highest OC burial rate on record for low-latitude reservoirs, probably resulting from high OC deposition onto the sediment compensating for high OC mineralization at 28–30?°C water temperature. Elevated OC burial was found near the dam, and close to major river inflow areas. C?:?N ratios between 10.3 and 17 (mean ± SD: 12.9?±?2.1) indicate that both land-derived and aquatic OC accumulate in CUN sediments. About 29?% of the sediment pore water samples had dissolved CH4 close to saturation concentration, a higher share than other hydroelectric reservoirs, indicating a high potential for CH4 ebullition, particularly in river inflow areas.Ramírez, D.A., Kreuze, J., Amoros, W., Valdivia-Silva, J.E., Ranck, J., Garcia, S., Salas, E., Yactayo, W., 2019. Extreme salinity as a challenge to grow potatoes under Mars-like soil conditions: targeting promising genotypes. International Journal of Astrobiology 18, 18-24. of the future challenges to produce food in a Mars environment will be the optimization of resources through the potential use of the Martian substratum for growing crops as a part of bioregenerative food systems. In vitro plantlets from 65 potato genotypes were rooted in peat-pellets substratum and transplanted in pots filled with Mars-like soil from La Joya desert in Southern Peru. The Mars-like soil was characterized by extreme salinity (an electric conductivity of 19.3 and 52.6 dS m?1 under 1 : 1 and saturation extract of the soil solution, respectively) and plants grown in it were under sub-optimum physiological status indicated by average maximum stomatal conductance <;50 mmol H2O m?2 s?1 even after irrigation. 40% of the genotypes survived and yielded (0.3–5.2 g tuber plant?1) where CIP.397099.4, CIP.396311.1 and CIP.390478.9 were targeted as promising materials with 9.3, 8.9 and 5.8% of fresh tuber yield in relation to the control conditions. A combination of appropriate genotypes and soil management will be crucial to withstand extreme salinity, a problem also important in agriculture on Earth that requires more detailed follow-up studies.Reagan, M.T., Queiruga, A.F., Moridis, G.J., 2019. Simulation of gas production from multilayered hydrate-bearing media with fully coupled flow, thermal, chemical and geomechanical processes using TOUGH+Millstone. Part 3: Production simulation results. Transport in Porous Media 129, 179-202. TOUGH+Millstone simulator has been developed for the analysis of coupled flow, thermal and geomechanical processes associated with the formation and/or dissociation of CH 4 CH4-hydrates in geological media. It is composed of two constituent codes: (a) a significantly enhanced version of the TOUGH+Hydrate simulator, v2.0, that accounts for all known flow, physical, thermodynamic and chemical processes associated with the evolution of hydrate-bearing systems and includes the most recent physical properties relationships, coupled seamlessly with (b) Millstone v1.0, a new code that addresses the conceptual, computational and mathematical shortcomings of earlier codes used to describe the geomechanical response of these systems. The capabilities of the TOUGH+Millstone code are demonstrated in the simulation and analysis of the system flow, thermal, and geomechanical behavior during gas production from a realistic complex offshore hydrate deposit. In the third paper of this series, we apply the simulators described in parts 1 and 2 to a problem of gas production from a complex, multilayered system of hydrate-bearing sediments in an oceanic environment. We perform flow simulations of constant-pressure production via a vertical well and compare those results to a coupled flow-geomechanical simulation of the same process. The results demonstrate the importance of fully coupled geomechanics when modeling the evolution of reservoir properties during production.Rebai, N., Hadjadj, A., Benmounah, A., Berrouk, A.S., Boualleg, S.M., 2019. Prediction of natural gas hydrates formation using a combination of thermodynamic and neural network modeling. Journal of Petroleum Science and Engineering 182, 106270. the treatment or transport of natural gas, the presence of water, even in very small quantities, can trigger hydrates formation that causes plugging of gas lines and cryogenic exchangers and even irreversible damages to expansion valves, turbo expanders and other key equipment. Hence, the need for a timely control and monitoring of gas hydrate formation conditions is crucial.This work presents a two-legged approach that combines thermodynamics and artificial neural network modeling to enhance the accuracy with which hydrates formation conditions are predicted particularly for gas mixture systems. For the latter, Van der Waals-Platteeuw thermodynamic model proves very inaccurate. To improve the accuracy of its predictions, an additional corrective term has been approximated using a trained network of artificial neurons. The validation of this approach using a database of 4660 data points shows a significant decrease in the overall relative error on the pressure from around 23.75%–3.15%. The approach can be extended for more complicated systems and for the prediction of other thermodynamics properties related to the formation of hydrates.Regoli, F., d’Errico, G., Nardi, A., Mezzelani, M., Fattorini, D., Benedetti, M., Di Carlo, M., Pellegrini, D., Gorbi, S., 2019. Application of a weight of evidence approach for monitoring complex environmental scenarios: the case-study of off-shore platforms. Frontiers in Marine Science 6, 377. doi: 10.3389/fmars.2019.00377. investigations based on integration of chemical and biological measurements, represent an added value to monitoring and management protocols, and their use is recommended by European Directives to evaluate environmental status of aquatic ecosystems. Nonetheless, assessing the overall significance of results from different studies is still a challenge. This work was aimed to present a quantitative Weight Of Evidence (WOE) model (Sediqualsoft) to integrate huge amounts of heterogeneous data and to validate this approach in complex monitoring scenarios. Using the case-study of off-shore platforms in the Adriatic Sea, procedures are presented to elaborate different typologies of data (lines of evidence, LOEs), including chemical characterization of sediments, bioavailability, biomarkers, ecotoxicological bioassays and benthic communities. These data are initially evaluated by logical flowcharts and mathematical algorithms, which provide specific hazard indices for each considered LOE, before their weighting and integration in an environmental risk index. The monitoring study selected for the WOE elaboration consisted on chemical analyses of trace metals, aliphatic hydrocarbons, polycyclic aromatic hydrocarbons carried out on 60 sediment samples; the same samples were characterized for the status of benthic communities; bioavailability of metals from sediments was assessed at laboratory conditions on the polychaete Hediste diversicolor, while bioaccumulation of inorganic and organic chemicals and biomarkers were measured in native and transplanted mussels; ecotoxicological properties of sediments were evaluated through a battery of bioassays determining algal growth of the diatom Phaeodactylum tricornutum, bioluminescence of the marine bacterium Vibrio fischeri, survival of the copepod Acartia tonsa and embryotoxicity of sea urchin Paracentrotus lividus. Almost 7000 analytical results were elaborated and summarized in specific hazard indices. The WOE integration of multiple typologies of data allowed more robust and weighted conclusions compared to the use of individual LOEs, highlighting the feasibility of this procedure for multidisciplinary monitoring and risk assessment approaches. On a practical side, the WOE evidences also suggested a revision of actual monitoring procedures. The proposed WOE model appears a useful tool to summarize large datasets of complex data in integrative indices, and to simplify the interpretation for stakeholders and decision makers, thus supporting a more comprehensive process of “site-oriented” management decisions.Reintjes, G., Tegetmeyer, H.E., Bürgisser, M., Orli?, S., Tews, I., Zubkov, M., Vo?, D., Zielinski, O., Quast, C., Gl?ckner, F.O., Amann, R., Ferdelman, T.G., Fuchs, B.M., 2019. On-site analysis of bacterial communities of the ultraoligotrophic South Pacific Gyre. Applied and Environmental Microbiology 85, e00184-19.: The South Pacific Gyre (SPG) covers 10% of the ocean’s surface and is often regarded as a marine biological desert. To gain an on-site overview of the remote, ultraoligotrophic microbial community of the SPG, we developed a novel onboard analysis pipeline, which combines next-generation sequencing with fluorescence in situ hybridization and automated cell enumeration. We tested the pipeline during the SO-245 “UltraPac” cruise from Chile to New Zealand and found that the overall microbial community of the SPG was highly similar to those of other oceanic gyres. The SPG was dominated by 20 major bacterial clades, including SAR11, SAR116, the AEGEAN-169 marine group, SAR86, Prochlorococcus, SAR324, SAR406, and SAR202. Most of the bacterial clades showed a strong vertical (20?m to 5,000?m), but only a weak longitudinal (80°W to 160°W), distribution pattern. Surprisingly, in the central gyre, Prochlorococcus, the dominant photosynthetic organism, had only low cellular abundances in the upper waters (20 to 80?m) and was more frequent around the 1% irradiance zone (100 to 150?m). Instead, the surface waters of the central gyre were dominated by the SAR11, SAR86, and SAR116 clades known to harbor light-driven proton pumps. The alphaproteobacterial AEGEAN-169 marine group was particularly abundant in the surface waters of the central gyre, indicating a potentially interesting adaptation to ultraoligotrophic waters and high solar irradiance. In the future, the newly developed community analysis pipeline will allow for on-site insights into a microbial community within 35?h of sampling, which will permit more targeted sampling efforts and hypothesis-driven research.Importance: The South Pacific Gyre, due to its vast size and remoteness, is one of the least-studied oceanic regions on earth. However, both remote sensing and in situ measurements indicated that the activity of its microbial community contributes significantly to global biogeochemical cycles. Presented here is an unparalleled investigation of the microbial community of the SPG from 20- to 5,000-m depths covering a geographic distance of ～7,000?km. This insight was achieved through the development of a novel onboard analysis pipeline, which combines next-generation sequencing with fluorescence in situ hybridization and automated cell enumeration. The pipeline is well comparable to onshore systems based on the Illumina platforms and yields microbial community data in less than 35?h after sampling. Going forward, the ability to gain on-site knowledge of a remote microbial community will permit hypothesis-driven research, through the generation of novel scientific questions and subsequent additional targeted sampling efforts.Remmelzwaal, S.R.C., Dixon, S., Parkinson, I.J., Schmidt, D.N., Monteiro, F.M., Sexton, P., Fehr, M.A., Peacock, C., Donnadieu, Y., James, R.H., 2019. Investigating ocean deoxygenation during the PETM through the Cr isotopic signature of foraminifera. Paleoceanography and Paleoclimatology 34, 917-929. the past several decades, oxygen minimum zones have rapidly expanded due to rising temperatures raising concerns about the impacts of future climate change. One way to better understand the drivers behind this expansion is to evaluate the links between climate and seawater deoxygenation in the past especially in times of geologically abrupt climate change such as the Palaeocene‐Eocene Thermal Maximum (PETM), a well‐characterized period of rapid warming ~56 Ma. We have developed and applied the novel redox proxies of foraminiferal Cr isotopes (δ53Cr) and Ce anomalies (Ce/Ce*) to assess changes in paleoredox conditions arising from changes in oxygen availability. Both δ53Cr and Cr concentrations decrease notably over the PETM at intermediate to upper abyssal water depths, indicative of widespread reductions in dissolved oxygen concentrations. An apparent correlation between the sizes of δ53Cr and benthic δ18O excursions during the PETM suggests temperature is one of the main controlling factors of deoxygenation in the open ocean. Ocean Drilling Program Sites 1210 in the Pacific and 1263 in the Southeast Atlantic suggest that deoxygenation is associated with warming and circulation changes, as supported by Ce/Ce* data. Our geochemical data are supported by simulations from an intermediate complexity climate model (cGENIE), which show that during the PETM anoxia was mostly restricted to the Tethys Sea, while hypoxia was more widespread as a result of increasing atmospheric CO2 (from 1 to 6 times preindustrial values).Rennó, N.O., Backhus, R., Cooper, C., Flatico, J.M., Fischer, E., Greer, L.C., Krasowski, M.J., Kremic, T., Martínez, G.M., Prokop, N.F., Sweeney, D., Vicente-Retortillo, A., 2019. A simple instrument suite for characterizing habitability and weathering: The Modern Aqueous Habitat Reconnaissance Suite (MAHRS). Astrobiology 19, 849-866. shallow subsurface of Mars is extremely interesting as a possible microbial habitat because it becomes temporarily wet, it is shielded from radiation, and mixing by aeolian processes could provide the sources of energy and nutrients necessary for sustaining microbial life in it. The Modern Aqueous Habitat Reconnaissance Suite (MAHRS) was developed primarily to search for potentially habitable environments in the shallow subsurface of Mars and to study weathering, but it can also be used to search for potentially habitable environments in the shallow subsurface of other planetary bodies such as the Icy Worlds. MAHRS includes an instrument developed to measure regolith wetness and search for brine in the shallow subsurface of Mars, where it is most likely to be found. The detection of brine can aid in our understanding not only of habitability but also of geochemistry and aqueous weathering processes. Besides the regolith wetness sensor, MAHRS includes an electric field sensor, an optical microscope, and a radiometer developed to characterize the near-surface environment and study mixing by aeolian processes. MAHRS was designed to aid in the selection of optimum areas for sample collection for return to Earth.Retallack, G.J., Mao, X., 2019. Paleoproterozoic (ca. 1.9?Ga) megascopic life on land in Western Australia. Palaeogeography, Palaeoclimatology, Palaeoecology 532, 109266. hairpin-shaped trace fossils (Myxomitodes stirlingensis) and discoid fossils (Cyclomedusa davidi) are here reinterpreted in a reassessment of sedimentology and paleosols of the 1.9?±?0.1?Ga Stirling Range Formation of Western Australia. Paleosols in the Stirling Range Formation were recognized from complex cracking patterns (peds and cutans), chemical and mineralogical zonation (soil horizons), and poikiloblastic crystals (desert roses). Redox profiles of the paleosols are evidence of well-drained profiles of a coastal plain under a low oxygen (433?±?116 ppmv) and carbon dioxide (564?±?64 ppmv) atmosphere. Gypsum pseudomorphs in paleosols that are deeply weathered chemically, represent a persistence of acid sulfate weathering, better known in Archean paleosols before the Great Oxidation event at 2.45?Ga. Chemical composition of the paleosols is evidence of a humid (1478?±?182?mm mean annual precipitation) temperate (11.3?±?0.5?°C mean annual temperature) paleoclimate. Their paleoenvironmental setting was a coastal plain on a passive tectonic margin. Megafossils were found on paleosols of western red sandstones of the Stirling Range Formation, not in gray shales and sandstones of marine facies to the east. Trace fossils (Myxomitodes stirlingensis) and discoid fossils are both found at the surface of well drained paleosols, and so were not metazoan trails, nor sea jellies. Myxomitodes was more likely a grex (“slug”) trail of soil slime molds, and the Cyclomedusa discoids, were probably microbial colonies. Pervasive microfilamentous structures in the paleosol surface are additional evidence of Paleoproterozoic microbial earth ecosystems.Reymond, C., Le Masle, A., Colas, C., Charon, N., 2019. A rational strategy based on experimental designs to optimize parameters of a liquid chromatography-mass spectrometry analysis of complex matrices. Talanta 205, 120063. high number of factors controlled by the experimenter has to be optimized to successfully separate, ionize and detect compounds when analyzing complex matrices by liquid chromatography hyphenated to high resolution mass spectrometry (LC-UV/MS). Key steps to manage such hyphenation are focused on desolvation and ionization processes. In this study, a design of experiments approach was used to optimize decisive parameters (i.e. nebulising, drying and sweep gas flow rates, ion transfer capillary voltage and temperature) for electrospray ionization and atmospheric pressure chemical ionization sources both in positive and negative modes. Central composite designs including 131 experiments each were built to cover rationally a sufficiently wide range of operating conditions. Each run was repeated three times to insure stable conditions of ionization and thus a satisfactory repeatability. Extracted ion chromatograms of twelve model oxygenated compounds were integrated and used as responses for experiment designs. Quadratic models for each standard allowed to take into account interactions between factors. Then responses were simultaneously maximized to achieve optimized factors. To illustrate the methodology relevance, optimal conditions were applied to a lignocellulosic biomass fast pyrolysis oil. Thanks to our high sensitivity method, a large number of molecular formulae was identified, as for instance in negative-ion mode electrospray with more than 5500 identified molecular formulae whereas analysis of the same sample by mass spectrometry without any prior chromatographic separation provided less than 2000 molecular formulae. In short, this study proposed a rational methodology to optimize ionization efficiency for LC-UV/MS analysis of complex mixtures.Rezazadeh, M., Seidi, S., Lid, M., Pedersen-Bjergaard, S., Yamini, Y., 2019. The modern role of smartphones in analytical chemistry. TrAC Trends in Analytical Chemistry 118, 548-555., in situ analysis attracts the interests and becomes one of the main purposes in analytical chemistry. Design of portable analysis devices facilitates reaching this goal. An ideal analysis system contains different parts enabling extraction, detection and quantification of target analytes. Preparation of a portable quantification approach is a bottle neck in such system creation. Common lab analysis instruments do not have the transportation ability and using these facilities limits the complete in situ analysis. Smartphones are the modern life phenomena and their usage becomes more widespread, every day. Their abilities and features are also swiftly developed. There are several strategies making the smartphone a suitable quantifier. This paper provides an overview of the currently applications of smartphones in analytical chemistry. Different applications of smartphones including optical detection (colorimetric, fluorescence, chemiluminescence, bioluminescence, and photoluminescence detections, pixelation as well as label-free detection), electrochemical detection, barcode reading, chemometric applications and smartphone imaging with fluorescence microscopy were classified and advantages and disadvantages of each approach were investigated. This modern common item could be a new part of analytical chemistry.Rigobello-Masini, M., Pereira, E.A.O., Abate, G., Masini, J.C., 2019. Solid-phase extraction of glyphosate in the analyses of environmental, plant, and food samples. Chromatographia 82, 1121-1138. review presents the state of the art concerning the strategies of solid-phase extraction of glyphosate and some of its metabolites in the analysis of environmental (water and soil), plant, and food samples. Glyphosate is the most used broad-spectrum herbicide around the world. As a consequence of this intense use, worries have arisen because of controversial questions regarding the risks glyphosate may pose to human health through dietary exposure, as well as to the equilibrium of ecosystems. Answers to these questions depend on efficient and reliable analytical methodologies that are applicable to monitoring programs. As a result of the complexity of sample matrices (especially soil and vegetable extracts) or the low concentrations of target analytes in natural water samples, solid-phase extraction has been used for either cleaning the extracts or enrichment of the analyte from highly diluted samples. The first part of this review introduces the current issues and controversies surrounding glyphosate, followed by systematic approaches used for its solid-phase extraction. Underivatized glyphosate can be extracted by strong anion exchange, immobilized metal affinity, and sorbents affording molecular recognition properties such as those of immunosorbents and molecular imprinted polymers. The use of new sorbents based on nanostructured materials for extraction of underivatized glyphosate is also addressed. Another approach describes the derivatization of glyphosate with 9-fluorenylmethyloxycarbonyl chloroformate which enables the retention of the product on hydrophobic sorbent phases, again aiming either at cleanup or analyte enrichment. Extraction strategies and the figures of merit of methods used in relevant applications are summarized in tables.Risum, A.B., Bro, R., 2019. Using deep learning to evaluate peaks in chromatographic data. Talanta 204, 255-260. of untargeted gas-chromatographic data is time consuming. With the earlier introduction of the PARAFAC2 (PARAllel FACtor analysis 2) based PARADISe (PARAFAC2 based Deconvolution and Identification System) approach in 2017, this task was made considerably more time-efficient. However, there are still a number of manual steps in the analysis which require data analytical expertise. One of these is the need to define whether or not each PARAFAC2 resolved component represents a peak suitable for integration. As the peaks may change in both shape and location on the elution time-axis, this presents a problem which cannot be readily solved by applying a linear classifier, such as PLS-DA (Partial Least Squares regression for Discriminant Analysis).As part of our ongoing efforts to further automate analysis of Gas Chromatography with Mass Spectrometry (GC-MS), we therefore explore a convolutional neural network classifier, capable of handling these shifts and variations in shape. The theory of convolutional neural networks and application on vector samples is briefly explained, and the performance is tested against a PLS-DA classifier, a shallow artificial neural network and a locally weighted regression model.The models are built on a training set with PARAFAC2 resolved components from eight different aroma related GC-MS runs with a total of over 70,000 elution profile samples, and validated using another, independent, GC-MS dataset.Based on Receiver Operating Characteristic curves (ROC) and manual analysis of the misclassified cases, it is shown that the convolutional network consistently outperforms the competing models, yielding an Area Under the Curve (AUC) value of 0.95 for peak classification. Examples are given illustrating that this new approach provides convincing means to automatically assess and evaluate modelled elution profiles of chromatographic data and thereby remove this laborious manual step.Rivas-Marin, E., Stettner, S., Gottshall, E.Y., Santana-Molina, C., Helling, M., Basile, F., Ward, N.L., Devos, D.P., 2019. Essentiality of sterol synthesis genes in the planctomycete bacterium Gemmata obscuriglobus. Nature Communications 10, 2916. and hopanoids are chemically and structurally related lipids mostly found in eukaryotic and bacterial cell membranes. Few bacterial species have been reported to produce sterols and this anomaly had originally been ascribed to lateral gene transfer (LGT) from eukaryotes. In addition, the functions of sterols in these bacteria are unknown and the functional overlap between sterols and hopanoids is still unclear. Gemmata obscuriglobus is a bacterium from the Planctomycetes phylum that synthesizes sterols, in contrast to its hopanoid-producing relatives. Here we show that sterols are essential for growth of G. obscuriglobus, and that sterol depletion leads to aberrant membrane structures and defects in budding cell division. This report of sterol essentiality in a prokaryotic species advances our understanding of sterol distribution and function, and provides a foundation to pursue fundamental questions in evolutionary cell biology.Robbins, L.J., Funk, S.P., Flynn, S.L., Warchola, T.J., Li, Z., Lalonde, S.V., Rostron, B.J., Smith, A.J.B., Beukes, N.J., de Kock, M.O., Heaman, L.M., Alessi, D.S., Konhauser, K.O., 2019. Hydrogeological constraints on the formation of Palaeoproterozoic banded iron formations. Nature Geoscience 12, 558-563. iron formations are critical to track changes in Archaean to Palaeoproterozoic ocean chemistry, with deposition triggered by water column iron oxidation. Recently, however, it was suggested that reduced iron minerals were the primary precipitates, and these were subsequently oxidized by oxygen-bearing groundwater. If true, this would cast doubt on our understanding of how banded iron formations were deposited and their ability to record early ocean chemistry. Here we present a hydrogeological box model, based on the approximately 2.5?billion year old Hamersley Basin of Western Australia, developed to evaluate the plausibility of secondary iron oxidation. The box model calculates the time required for groundwater to flux enough oxygen through the basin to oxidize a given amount of ferrous iron. Less than 9% of nearly four million model iterations returned oxidation times less than the age of the basin. Successful simulations required simultaneously steep hydraulic gradients, high permeability and elevated oxygen concentrations. Our simulations show that the postdepositional oxidation of large banded iron formations is unlikely, except on a limited scale (that is, during secondary ore formation), and that oxidized iron phases were probably the precursor to large Palaeoproterozoic banded iron formations.Rocío-Bautista, P., Termopoli, V., 2019. Metal–organic frameworks in solid-phase extraction procedures for environmental and food analyses. Chromatographia 82, 1191-1205. and food analysis?usually require the use of sample preparation steps, with significant utilization of solid-phase extraction techniques. This review article covers recent trends in the use of metal–organic frameworks (MOFs) as novel sorbents, with particular emphasize on miniaturized methods to follow green analytical chemistry principles. Thus, the use of MOFs in miniaturized solid-phase extraction (?SPE), performed in static off-line and on-line modes, and solid-phase microextraction (SPME), including the on-line procedures of in-tube and on-disk approaches, will be described with particular emphasis on the specific applications.Rommevaux, C., Henri, P., Degboe, J., Chavagnac, V., Lesongeur, F., Godfroy, A., Boulart, C., Destrigneville, C., Castillo, A., 2019. Prokaryote communities at active chimney and in situ colonization devices after a magmatic degassing event (37°N MAR, EMSO-Azores Deep-Sea Observatory). Geochemistry, Geophysics, Geosystems 20, 3065-3089. The mixing zone between high-temperature hydrothermal fluids and seawater produces redox gradients, promoting the development of unique ecosystems based on chemotrophy. The structure of microbial communities depends on their environment, which can vary according to space and time. Hydrothermal circulation within the oceanic crust determines the chemical composition and flow of fluids, depending on underground events (earthquakes, volcanic episodes, etc.) and impacts the development of microbial communities. This link between hydrothermal vent communities and deep geological events is the focus of the present study, the first of its kind for slow-spreading ridge. In this study, we present a unique set of multidisciplinary data collected from 2008 to 2011 on the Eiffel Tower hydrothermal site (Lucky Strike vent field, Mid-Atlantic Ridge, MAR). We benefit from continuous geophysical monitoring (temperature and seismicity) of the site, annual sampling of hydrothermal fluids (hot and diffuse) for geochemistry analyses, sampling of hydrothermal chimneys, and an in situ microbial colonization experiment over a year for microbial study. The high CO2 content and concentrations of major elements (Cl, Ca, and Si) and SO4 in the end-member fluids collected in 2010 indicate that a magmatic degassing occurred between 2009 and 2010 under the Lucky Strike hydrothermal field. This is supported by the large temperature variations observed in March?April 2010. These magmatic CO2 inputs seem to have affected microbial communities colonizing the high-temperature chimney, as well as the basalts in the more diffuse and mixed zone, promoting the development of thermophilic/anaerobic Archaea and Bacteria (Archaeoglobales, Nautiliales, and Nitratiruptoraceae).Rothman, D.H., 2019. Characteristic disruptions of an excitable carbon cycle. Proceedings of the National Academy of Sciences 116, 14813-14822.: The great environmental disruptions of the geologic past remain enigmatic. Each one results in a temporary change in the oceans’ store of carbon. Although the causes remain controversial, these changes are typically interpreted as a proportionate response to an external input of carbon. This paper suggests instead that the magnitude of many disruptions is determined not by the strength of external stressors but rather by the carbon cycle’s intrinsic dynamics. Theory and observations indicate that characteristic disruptions are excited by carbon fluxes into the oceans that exceed a threshold. Similar excitations follow influxes that are either intense and brief or weak and long-lived, as long as they exceed the threshold. Mass extinction events are associated with influxes well above the threshold.Abstract: The great environmental disruptions of the geologic past remain enigmatic. Each one results in a temporary change in the oceans’ store of carbon. Although the causes remain controversial, these changes are typically interpreted as a proportionate response to an external input of carbon. This paper suggests instead that the magnitude of many disruptions is determined not by the strength of external stressors but rather by the carbon cycle’s intrinsic dynamics. Theory and observations indicate that characteristic disruptions are excited by carbon fluxes into the oceans that exceed a threshold. Similar excitations follow influxes that are either intense and brief or weak and long-lived, as long as they exceed the threshold. Mass extinction events are associated with influxes well above the threshold.The history of the carbon cycle is punctuated by enigmatic transient changes in the ocean’s store of carbon. Mass extinction is always accompanied by such a disruption, but most disruptions are relatively benign. The less calamitous group exhibits a characteristic rate of change whereas greater surges accompany mass extinctions. To better understand these observations, I formulate and analyze a mathematical model that suggests that disruptions are initiated by perturbation of a permanently stable steady state beyond a threshold. The ensuing excitation exhibits the characteristic surge of real disruptions. In this view, the magnitude and timescale of the disruption are properties of the carbon cycle itself rather than its perturbation. Surges associated with mass extinction, however, require additional inputs from external sources such as massive volcanism. Surges are excited when CO2 enters the oceans at a flux that exceeds a threshold. The threshold depends on the duration of the injection. For injections lasting a time ti ?10,000 y in the modern carbon cycle, the threshold flux is constant; for smaller ti, the threshold scales like ti ?1. Consequently the unusually strong but geologically brief duration of modern anthropogenic oceanic CO2 uptake is roughly equivalent, in terms of its potential to excite a major disruption, to relatively weak but longer-lived perturbations associated with massive volcanism in the geologic past.Rubanenko, L., Venkatraman, J., Paige, D.A., 2019. Thick ice deposits in shallow simple craters on the Moon and Mercury. Nature Geoscience 12, 597-601. shadowed regions near the poles of Mercury and the Moon may cold-trap water ice for geologic time periods. In past studies, thick ice deposits have been detected on Mercury, but not on the Moon, despite their similar thermal environments. Here we report evidence for thick ice deposits inside permanently shadowed simple craters on both Mercury and the Moon. We measure the depth/diameter ratio of approximately 2,000 simple craters near the north pole of Mercury using Mercury Laser Altimeter data. We find that these craters become distinctly shallower at higher latitudes, where ice is known to have accumulated on their floors. This shallowing corresponds to a maximum infill of around 50?m, consistent with previous estimates. A parallel investigation of approximately 12,000 lunar craters using Lunar Reconnaissance Orbiter data reveals a similar morphological trend near the south pole of the Moon, which we conclude is also due to the presence of thick ice deposits. We find that previously detected surface ice deposits in the south polar region of the Moon are spatially correlated with shallow craters, indicating that the surface ice may be exhumed or linked to the subsurface via diffusion. The family of lunar craters that we identify are promising targets for future missions, and may also help resolve the apparent discrepancy between the abundance of frozen volatiles on Mercury and the Moon.Russell, M.J., 2019. Figuring out how life first took off is (much like) rocket science! Planetary and Space Science 175, 13-20. pedagogical comparison of emergence-of-life research and rocket science is made in order to inform how environmental disequilibria at the ocean/crust interface on the early Earth – a 1?V battery – forced life's emergence as an inescapable mechanism for their dissipation. Likely fuels and oxidants to drive life into being were hydrogen plus methane, borne by rising alkaline hydrothermal solutions, juxtaposed with ocean waters containing dilute nitric plus carbonic acids carbureted along the outside of a spontaneously precipitated semipermeable metal hydroxide/sulfide mound. As a comparison, hydrogen and methane can also be used as fuels for rockets, with nitric acid as an oxidant, carefully distributed through the mixing head to the combustion chamber. Whereas a full burn is the goal of the rocket engineer, the first living entities were best served by incomplete reactions and thereby the production of metastable intermediates that could further interact to beat the first metabolic pathway to life. In this analogy the hydrothermal mound is broadly comparable to the rocket while individual engines comprise the variable valence and conformationally flexible mineral, green rust (～[Fe2+4Fe3+2(OH12]2+[CO3.3H2O]2-) dosed with Ni, Co, Mo and W. With its internal layers of water and counter ions, we also compare the operations of green rust to a slow ramjet. This green rust ‘ramjet’ is driven by steep gradients in protons, electrons, anions and uncharged molecules, through the hydrous interlayers from either side of the mineral membrane separating the contrasting fluids and which green rust partly comprises. The mineral can rapidly reduce nitrate to ammonia and, therefrom, aminate pyruvate to the amino acid alanine. The higher amino acids may also be synthesized and polymers thereby act as primitive proteins, enzymes and cell walls. The main challenge now is to figure out how this green rust system, with its variable valence pattern of 2 ?+ ?and 3 ?+ ?cations, could govern growth and reproduction and, eventually, evolve toward a replicative world partly governed by nucleotides. Inanimate rockets of course, need their guidance systems installed, and most are fully autonomous.Sabadel, A.J.M., Van Oostende, N., Ward, B.B., Woodward, E.M.S., Van Hale, R., Frew, R.D., 2019. Characterization of particulate organic matter cycling during a summer North Atlantic phytoplankton bloom using amino acid C and N stable isotopes. Marine Chemistry 214, 103670. asbstract. In this study, we used AA isotopic markers as proxies, along with more conventional analyses, such as flow cytometry and nutrient concentrations, and PON and NO?3 isotopic composition, to describe in situ elemental cycling at the base of pelagic food webs during a late summer North Atlantic Ocean bloom, and to track the origin, composition and fate of organic C and N. Most of these proxies, developed in a laboratory setting, proved to be useful tools to characterize POM cycling in the water column compared to standard measures of biomass composition, especially when used in combination with each other. The bivariate scatter plot of Leu and Ile Norm(δ13CAA) in the ML revealed the dominant phytoplankton-derived AA contribution to POM at both late summer bloom stations. The POM trophic position (TP ~ 1.6) derived from δ15NAA indicated the presence of organic matter originating from higher trophic positions, such as heterotrophic micro-eukaryotes and multicellular zooplankton in addition to the strong primary producer signal. This TP signal was closely tracked by the 15N depletion of Thr, a metabolic AA, with depth. Based on the pattern of variation in δ15NAA throughout the water column, hydrolysis of proteins by heterotrophic microbes was probably the main POM degradation process at work, as opposed to the resynthesis of POM represented by the δ15NAA-based heterotrophic resynthesis proxy (ΣV).However, while CSIA-AA represent a useful and complementary tool to more traditional techniques and approaches, it still has some limitations and caveats that needs to be address in future research. This study also indicates research areas where improvements would yield a more refined use of CSIA-AA proxies for C and N cycling in the ocean. For example, the establishment of baseline patterns in δ13CAA and δ15NThr across different marine environments and ocean basins would make it possible to capture the effect of primary producer community composition, and the influence of N source (NO3? or DON, NH4+) on their δ15NAA composition. The combination of this approach with in situ isotopic tracer experiments to estimate these N sources uptake rates would be a way to test this. Finally, δ15NThr seems to have promising biomarker properties, including the possility of assesing TP based on it's ‘reverse-fractionation’ behavior. The developmennt of a TP proxy using δ15NThr values (see Fig. S8) would benefit from targeted in situ feeding experiments when possible. Overall, these research developments would augment the value of CSIA as a biogeochemical tool to track elemental cycling and trophic exchange in the variable marine environment.Saier, M.H., 2019. Understanding the genetic code. Journal of Bacteriology 201, e00091-19. universal triple-nucleotide genetic code is often viewed as a given, randomly selected through evolution. However, as summarized in this article, many observations and deductions within structural and thermodynamic frameworks help to explain the forces that must have shaped the code during the early evolution of life on Earth.Saigusa, D., Saito, R., Kawamoto, K., Uruno, A., Kano, K., Aoki, J., Yamamoto, M., Kawamoto, T., 2019. Conductive adhesive film expands the utility of matrix-assisted laser desorption/ionization mass spectrometry imaging. Analytical Chemistry 91, 8979-8986. matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) technique is a promising approach for detecting the distribution of small molecules in a section of biological tissue. However, when a cryosection is created from fragile, hard, or whole-body samples, obtaining a high-quality section that maintains the distribution of the various components has been difficult. Since adhesive films have the potential to obtain high-quality cryosections, we attempted to utilize a conductive adhesive film for MALDI-MSI. To this end, cryosections of the whole body of a 9-day-old mouse were directly prepared on indium tin oxide (ITO) glass slides, nonconductive adhesive films, or conductive adhesive films, and the signal intensities from each section were measured by MALDI-MSI. We measured the differences in the ion intensity among these three slides/films by means of multivariate analyses and found that both the nonconductive and conductive adhesive films gave rise to high-quality sections in comparison with the ITO glass slide. The conductive adhesive film gave higher signals that were comparable to those of the ITO glass slide in comparison with the nonconductive adhesive film. We divided the frozen sections into two groups, a freeze-dried group and a thawed group, to examine the freeze–thaw effect on the signals of representative compounds of amino acids, cholesterol, and phosphatidylcholines. The freeze-dried samples were found to be useful for the analysis. These results indicate that the sections made with the conductive adhesive film under a freeze-dried condition can expand the utility of the MALDI-MSI analysis.Saitta, E.T., Liang, R., Lau, M.C.Y., Brown, C.M., Longrich, N.R., Kaye, T.G., Novak, B.J., Salzberg, S.L., Norell, M.A., Abbott, G.D., Dickinson, M.R., Vinther, J., Bull, I.D., Brooker, R.A., Martin, P., Donohoe, P., Knowles, T.D.J., Penkman, K.E.H., Onstott, T., 2019. Cretaceous dinosaur bone contains recent organic material and provides an environment conducive to microbial communities. eLIFE 8, e46205. were thought to lack original organic molecules, but chemical analyses show that some can survive. Dinosaur bone has been proposed to preserve collagen, osteocytes, and blood vessels. However, proteins and labile lipids re diagenetically unstable, and bone is a porous open system, allowing microbial/molecular flux. These ‘soft tissues’ have been reinterpreted as biofilms. Organic preservation versus contamination of dinosaur bone was examined by freshly excavating, with aseptic protocols, fossils and sedimentary matrix, and chemically/biologically analyzing them. Fossil ‘soft tissues’ differed from collagen chemically and structurally; while degradation would be expected, the patterns observed did not support this. 16S rRNA amplicon sequencing revealed that dinosaur bone hosted an abundant microbial community different from lesser abundant communities of surrounding sediment. Subsurface dinosaur bone is a relatively fertile habitat, attracting microbes that likely utilize inorganic nutrients and complicate identification of original organic material. There exists potential post-burial taphonomic roles for subsurface microorganisms.Sajjad, W., Zheng, G., Rafiq, M., Ma, X., Khan, S., Haq, A., Ali, B., Zada, S., 2019. Evaluation of the biotechnological potential of pure and mixture of indigenous iron-oxidizing bacteria to dissolve trace metals from Cu bearing ore. Geomicrobiology Journal 36, 715-726. study aimed to investigate the ability of pure and consortia of indigenous iron-oxidizing bacteria to enhance the dissolution of trace metals from Cu and Zn-bearing ore. Three bacterial strains Acidithiobacillus ferrooxidans strain WG101, Leptospirillum ferriphilum strain WG102, Leptospirillum ferrooxidans strain WG103 isolated from Baiyin copper mine, China were used in this study. The biotechnological potential of these indigenous isolates was evaluated both in pure and in consortia to extract cobalt, chromium, and lead from the copper and zinc bearing ore. The sulfur and iron-oxidizing bacterial isolate Acidithiobacillus ferrooxidans strain WG101 exhibited efficient dissolution compared to sole iron-oxidizing Leptospirillum ferriphilum strain WG102, and Leptospirillum ferrooxidans strain WG103. Initial medium pH, pulp density, and temperature were studied as influential parameters in bioleaching carried out by bacterial consortia. The achieved optimum conditions were; initial pH of 1.5, 10% of pulp density, and temperature 30?°C with 68.7?±?3.9% cobalt, 56.6?±?3.9% chromium, and 36?±?3.7% lead recovery. Analytical study of oxidation-reduction potential and pH fluctuation were observed during this whole process that shows the metal dissolution efficiency of bacterial consortia. Alterations in spectral bands of processed residues were reported through FTIR analysis compared with control ore sample. M?ssbauer spectroscopy analysis showed the influence of bacterial consortia on iron speciation in bioleached samples. The findings confirm that the indigenous acidophilic iron-oxidizing bacterial strains are highly effective in the dissolution of trace elements present in ore samples. This study not only supports the notion that indigenous bacterial strains are highly effectual in metal dissolution but provides the basic vital conditions to upscale the bioleaching technique for metals dissolution.Samuels, T., Pybus, D., Wilkinson, M., Cockell, C.S., 2019. pH influences the distribution of microbial rock-weathering phenotypes in weathered shale environments. Geomicrobiology Journal 36, 752-763. rock weathering of shale forms an important part of global biogeochemical cycling and soil formation. Culture-independent analyses have revealed diverse microbial communities in weathered shale environments, yet few studies have attempted to discern the functional ecology of such communities in relation to their rock weathering capabilities. In this study, phenotypic plate assays were used to determine the abundance of microbes with different rock weathering phenotypic traits in weathered shale environments. A physicochemical parameter (pH) is shown to influence the abundance of aerobic rock weathering microbes in weathered shale. Iron and manganese oxidizers were restricted to acidic environments while siderophore producing and alkaline phosphatase producing microbes were largely confined to pH neutral environments. Furthermore, a clear separation in the spatial distribution of aerobic-iron oxidizing and siderophore-producing microbes, as defined by a pH gradient across the sites sampled, was demonstrated. Phylogenetic analysis of isolates revealed that siderophore-producing and alkaline phosphatase producing bacteria belonged to commonly identified rock weathering genera including Arthrobacter, Pseudomonas, and Streptomyces. These results enhance our understanding of how physicochemical parameters can define the composition and rock weathering potential of microbial communities.Sánchez-Murillo, R., Romero-Esquivel, L.G., Jiménez-Antillón, J., Salas-Navarro, J., Corrales-Salazar, L., ?lvarez-Carvajal, J., ?lvarez-McInerney, S., Bonilla-Barrantes, D., Gutiérrez-Sibaja, N., Martínez-Arroyo, M., Ortiz-Apuy, E., Salgado-Lobo, J., Villalobos-Morales, J., Esquivel-Hernández, G., Rojas-Jiménez, L.D., Gómez-Castro, C., Jiménez-Madrigal, Q., Vargas-Gutiérrez, O., Birkel, C., 2019. DOC transport and export in a dynamic tropical catchment. Journal of Geophysical Research: Biogeosciences 124, 1665-1679.: Dissolved organic carbon (DOC) transport and export from headwater forests into freshwaters in highly dynamic tropical catchments are still understudied. Here we present a DOC analysis (2017) in a pristine and small (~2.6 km2) tropical catchment of Costa Rica. Storm flows governed a rapid surface and lateral allochthonous DOC transport (62.2% of the annual DOC export). Cross‐correlation analysis of rainfall and stream discharge indicated that DOC transport occurred on average ~1.25 hr after the rainfall maxima, with large contributions of event water, ranging from 42.4±0.3% up to 98.2±0.3% of the total discharge. Carbon export flux (annual mean=6.7±0.1 g C · m‐2 · year‐1) was greater than values reported in subtropical and temperate catchments. Specific ultraviolet absorbance indicated a mixture of hydrophobic humic and hydrophilic nonhumic matter during both baseflow and storm events. Our results highlight the rapid storm‐driven DOC transport and export as well as low biogeochemical attenuation during baseflow episodes in a climate sensitive hot spot. By understanding the key factors controlling the amount of organic carbon transported to streams in dynamic tropical landscapes, better global‐ and catchment‐scale model assessments, conservation practices, and water treatment innovations can be identified.Plain Language Summary: Humid tropical forests represent ~20% of the global soil organic matter reservoirs. Nutrient availability coupled with transport and export of dissolved organic carbon (DOC) from forests into freshwater ecosystems is still poorly understood in the tropics. Here we present a study of DOC dynamics in a humid tropical catchment of central Costa Rica. Overall, DOC was transported from the forest to the stream on average within ~1.25 hr after large rainfall events. Storm flows were dominated by event water (recent rainfall) in the catchment. Fluvial carbon flux exported from the catchment was estimated at 6.7±0.1 g C · m‐2 · year‐1. Our results highlight the rapid DOC transport and export during storm flows as well as low biodegradation during baseflow episodes. These findings may contribute to improve model calibration and validation considering the limited high‐resolution DOC data in dynamic tropical landscapes.Sanyal, S., Bhui, U.K., Balaga, D., Kumar, S.S., 2019. Interaction study of montmorillonite-crude oil-brine: Molecular-level implications on enhanced oil recovery during low saline water flooding from hydrocarbon reservoirs. Fuel 254, 115725. molecular level insights of the interaction between the reservoir rock-crude oil-brine are very crucial for designing effective injection water during low saline water flooding for optimum oil recovery. Present work is an attempt to study the interaction phenomenon that takes place between different reservoirs components considering clay, two dead crude oils (C1 and C2), and different concentrations of brine (2000–8000?ppm). The clay used in this study is montmorillonite with a stoichiometric composition (Na0.63Ca0.26K0.1) (Al2.66Ti0.44Fe0.60Mg0.61) (Si6.538Al1.46) (OH)4. Crude oil C1 is lighter having 3?wt% asphaltene dominating with 3–5 fused aromatic ring (FAR) structures while C2 is heavier than C1 containing 7.5?wt% asphaltenes with a significant presence of 5–7 FAR. Experimentation and detailed analysis of the dry (Mt) and oil-treated montmorillonite (MtC1, and MtC2) connote that the polar oil components particularly, asphaltenes are adsorbed onto the interlayer surfaces of montmorillonite. Spectroscopic results of oil treated Mt and saline water reveal that low saline water (2000?ppm) of Na+ and Ca++ ions are equally capable of removing 3–5 ring size FAR of polycyclic aromatic hydrocarbon (PAH) components from the montmorillonite interlayer surfaces. Thus, the present study attests to the fact that the type of cation present in their interlayer surface of montmorillonite, and the ring size of PAH in asphaltenes influence the interaction phenomenon where molecular level insights between oil treated montmorillonite and saline water are valuable for designing effective injection fluids for EOR.Sanz-Novo, M., Largo, A., Redondo, P., Barrientos, C., 2019. Formation of protonated glycine isomers in the interstellar medium. ACS Earth and Space Chemistry 3, 1170-1181. computational study of protonated glycine isomers with [H6C2O2N]+ molecular formula has been carried out. All of them are possible products of the reaction between protonated hydroxylamine and acetic acid. All reaction processes that could form the [H6C2O2N]+ isomers considered in this work are exothermic except for those initiated by the most stable isomer of protonated hydroxylamine which give CH3CONH2+OH and CH3COHNOH2+ isomers. The analysis of the potential energy surfaces corresponding to the reaction of protonated hydroxylamine and acetic acid has been focused on the most abundant products, namely, CH3CONH2+OH, CH3COONH3+, and CH3C(OH)+ONH2, obtained from a previous chemical dynamics simulations study. From this analysis we found that even if the reactions of formation of the CH3COONH3+ and the CH3C(OH)+ONH2 isomers are exothermic processes, significant activation barriers were found in the paths leading to these products. The only exothermic process (ΔE = ?23.9 kcal mol–1 at the CCSD(T) level) with no net activation barrier was initiated by the high-energy isomer of protonated hydroxylamine, which leads to the CH3CONH2+OH isomer. Therefore, the formation of this isomer could be feasible under interstellar conditions from the reaction of the less stable isomer of protonated hydroxylamine and acetic acid. In addition, an analysis of their neutral counterparts, with [H5C2O2N] molecular formula, has been carried out. The relevant spectroscopic parameters for [H6C2O2N]+ and [H5C2O2N] isomers that could help in their laboratory or astronomical detection, by radioastronomy or infrared spectroscopy, are reported.Sayyad Amin, J., Rajabi Kuyakhi, H., Bahadori, A., 2019. Prediction of formation of polycyclic aromatic hydrocarbon (PAHs) on sediment of Caspian Sea using artificial neural networks. Petroleum Science and Technology 37, 1987-2000. this article the amount of polycyclic aromatic hydrocarbon (PAHs) on the sediment of Caspian Sea predicted by artificial neural networks multi-layer perceptron (MLP) and generalized regression (GRNN) models. PAH is a most important pollutant in a marine environment derived from an anthropogenic and natural source. This component is mutagenic and Carcinogenic extremely. In this investigation, a multi-layer perceptron and Generalized regression neural network models have been developed by experimental data (organic matter, latitude, longitude, depth and effective matter (particle size)) reported in the literature. As a result, experimental data compared to the output of models by calculation of mean squared error (MSE), root mean squared error (RMSE), mean absolute error percent (MEAE), maximum absolute error percent (MAAE) and R2. Results have shown an appropriate fitting for experimental data with predicted values .Also, MLP neural network has the best performance to predicating of PAHs.Sazhin, A.F., Romanova, N.D., Kopylov, A.I., Zabotkina, E.A., 2019. Bacteria and viruses in Arctic sea ice. Oceanology 59, 339-346. studied vertical distribution of bacteria and viruses in different layers of the Arctic sea ice drilled at the North Pole. The sampled multi-year ice was characterized by uneven vertical distribution of bacterial abundance. This characteristic varied within the range of 8 ± 1.2 × 103 to 95 ± 2.6 × 103 cells mL–1. The layers with the maximal bacterial abundance were located in the intermediate and lower layers of the ice cores. Bacterial biomass varied from 0.5 to 5 mg C m–3 with the mean value 1.57 ± 0.2 mg C m–3. The ratio of viral to bacterial abundance varied from 0.6 to 28, with the mean value 12.5. The average total number of phages attached to bacteria was 6.2 × 103 viral particles mL–1. The number of viral particles located within the bacterial cells varied from 2 to 21 particles per a bacterial cell. The frequency of visibly infected bacterial cells (FVIC) calculated for the upper, intermediate and lower layers of the ice was 0.92, 1.23 and 0.8% of the total bacterial abundance, respectively. The overall frequency of infected cells (FIC) calculated for the same layers was 6.3, 8.4 and 0.8% of bacteria numbers, respectively, while the viral-mediated mortality of bacteria (VMB) was 7.1, 9.8 and 6.1%, respectively. Our data show that during the study period the rate of viral infection of bacterial cells and the viral-mediated mortality of bacterial cells in the multy-year ice of the North Pole were relatively low.Schemeth, D., Nielsen, N.J., Andersson, J.T., Christensen, J.H., 2019. A tiered analytical approach for target, non-target and suspect screening analysis of polar transformation products of polycyclic aromatic compounds. Chemosphere 235, 175-184. aromatic compounds (PACs) possess toxicity towards humans, and their presence in the environment is unwanted. Polar transformation products (TPs) are more mobile, and can be considered emerging contaminants, as they represent a more bioavailable carrier of the same toxic properties. Acidic TPs has been proposed as an important class of polar TPs. This study presents a tiered analytical approach to investigate acidic and polar PAC TPs in environmental conditions. The tiered approach exploits target analysis for quantification of acids; suspect screening for tentative identification based on retention time and spectral matching using databases; and finally non-target analysis based on chromatography and data independent broadband MS to highlight potentially unknown analyte peaks. The approach includes a mixed-mode anion exchange solid phase extraction (MAX-SPE) to fractionate neutral and acidic compounds, and is applied to three cases: I) Photo-oxidation of six PACs generated suspected hydroxylated-, carbonylated- and carboxylated PACs but also proposed the presence of mono- and dicarboxylic acids, which have not been reported elsewhere. For a subset of four acids, conversion rates were determined. II) Recovery of spiked acids from diesel spilled harbor water was 80% by LC-MS, and diesel spill weathering was evaluated from the neutral fraction by GC-MS. III) By non-target analysis sulfonated PACs, presumable derived from photo-oxidation, were detected in run-off basins of an arctic landfarm, alongside hypothesized naturally occuring fatty acids. The tiered approach is a sensitive and versatile tool to extract information on PACs and their polar TPs from polluted environmental sites.Schilling, I.E., Bopp, C.E., Lal, R., Kohler, H.-P.E., Hofstetter, T.B., 2019. Assessing aerobic biotransformation of hexachlorocyclohexane isomers by compound-specific isotope analysis. Environmental Science & Technology 53, 7419-7431. of soils and sediments with the highly persistent hexachlorocyclohexanes (HCHs) continues to be a threat for humans and the environment. Despite the existence of bacteria capable of biodegradation and cometabolic transformation of HCH isomers, such processes occur over time scales of decades and are thus challenging to assess. Here, we explored the use of compound-specific isotope analysis (CSIA) to track the aerobic biodegradation and biotransformation pathways of the most prominent isomers, namely, (?)-α-, (+)-α-, β-, γ-, and δ-HCH, through changes of their C and H isotope composition in assays of LinA2 and LinB enzymes. Dehydrochlorination of (+)-α-, γ-, and δ-HCH catalyzed by LinA2 was subject to substantial C and H isotope fraction with apparent 13C- and 2H-kinetic isotope effects (AKIEs) of up to 1.029 ± 0.001 and 6.7 ± 2.9, respectively, which are indicative of bimolecular eliminations. Hydrolytic dechlorination of δ-HCH by LinB exhibited even larger C but substantially smaller H isotope fractionation with 13C- and 2H-AKIEs of 1.073 ± 0.006 and 1.41 ± 0.04, respectively, which are typical for nucleophilic substitutions. The systematic evaluation of isomer-specific phenomena showed that, in addition to contaminant uptake limitations, diffusion-limited turnover ((?)-α-HCH), substrate dissolution (β-HCH), and potentially competing reactions catalyzed by constitutively expressed enzymes might bias the assessment of HCH biodegradation by CSIA at contaminated sites.Schmidt, G.A., Frank, A., 2019. The Silurian hypothesis: would it be possible to detect an industrial civilization in the geological record? International Journal of Astrobiology 18, 142-150. an industrial civilization had existed on Earth many millions of years prior to our own era, what traces would it have left and would they be detectable today? We summarize the likely geological fingerprint of the Anthropocene, and demonstrate that while clear, it will not differ greatly in many respects from other known events in the geological record. We then propose tests that could plausibly distinguish an industrial cause from an otherwise naturally occurring climate event.Schmitz, B., Feist, R., Meier, M.M.M., Martin, E., Heck, P.R., Lenaz, D., Topa, D., Busemann, H., Maden, C., Plant, A.A., Terfelt, F., 2019. The micrometeorite flux to Earth during the Frasnian–Famennian transition reconstructed in the Coumiac GSSP section, France. Earth and Planetary Science Letters 522, 234-243. have reconstructed the distribution of extraterrestrial chrome spinels in a marine limestone section across the Frasnian–Famennian stratotype section at Coumiac in southern France, providing the first insights on the types of micrometeorites and meteorites that fell on Earth at this time. The data can test whether the small cluster of roughly coeval, large impact structures is related to an asteroid breakup and shower with possible bearings also on the late Devonian biodiversity crisis. A total of ～180 extraterrestrial spinel grains (>32 μm) were recovered from 957 kg of rock. Noble-gas measurements of individual grains show high solar-wind content, implying an origin from decomposed micrometeorites. Element analyses indicate a marked dominance of ordinary chondritic over achondritic grains, similar to the recent flux. The relation between H, L and LL meteorites is ～29–58–13%, similar to the late Silurian flux, ～31–63–6%, but different from the distribution, ～45–45–10%, in the recent and the Cretaceous flux. Our data show no indication of a generally enhanced late Devonian micrometeorite flux that would accompany an asteroid shower. However, in a single limestone bed that formed immediately before the Upper Kellwasser horizon, that represents the main end-Frasnian species-turnover event, we found an enrichment of ～10 ordinary chondritic grains (>63 μm) per 100 kg of rock, compared to the ～1–3 grains per 100 kg that characterise background. The anomalously abundant grains are of mixed H, L and LL types and may be related to an enhanced flux of extraterrestrial dust during postulated minima in both the 405 ka and 2.4 Ma Earth-orbit eccentricity cycles at the onset of the Upper Kellwasser event. In the present solar system the dust accretion at Earth is the highest at eccentricity minima because of the spatial distribution of dust bands of the zodiacal cloud. Besides this small grain anomaly the data here and in previous studies support a stable meteorite flux through the late Silurian and Devonian, in contrast to the mid-Ordovician, when achondritic meteorites that are rare on Earth today were common, followed by the influx of a flood of debris related to the breakup of the L-chondrite parent body. Our accumulated data for six time windows through the Phanerozoic indicate that the ordinary chondrites make up a major fraction in the meteorite flux since at least the mid-Ordovician. We note that the sources in the asteroid belt of the H and L meteorites, the two most common types of meteorites today and through much of the Phanerozoic, remain elusive.Schwank, K., Bornemann, T.L.V., Dombrowski, N., Spang, A., Banfield, J.F., Probst, A.J., 2019. An archaeal symbiont-host association from the deep terrestrial subsurface. The ISME Journal 13, 2135-2139. archaea have reduced metabolic capacities and are diverse and abundant in deep aquifer ecosystems, yet little is known about their interactions with other microorganisms that reside there. Here, we provide evidence for an archaeal host-symbiont association from a deep aquifer system at the Colorado Plateau (Utah, USA). The symbiont, Candidatus Huberiarchaeum crystalense, and its host, Ca. Altiarchaeum hamiconexum, show a highly significant co-occurrence pattern over 65 metagenome samples collected over six years. The physical association of the two organisms was confirmed with genome-informed fluorescence in situ hybridization depicting small cocci of Ca. H. crystalense attached to Ca. A. hamiconexum cells. Based on genomic information, Ca. H. crystalense potentially scavenges vitamins, sugars, nucleotides, and reduced redox-equivalents from its host and thus has a similar metabolism as Nanoarchaeum equitans. These results provide insight into host-symbiont interactions among members of two uncultivated archaeal phyla that thrive in a deep subsurface aquifer.Schwartz, J.S.J., 2019. Where no planetary protection policy has gone before. International Journal of Astrobiology 18, 353-361. argue that the attempts of astrobiologists and philosophers to provide an ethical justification for planetary protection policies (in particular, those aspects of policy concerning forward contamination) suffer from a ‘life bias’ in that reasons for protection are regarded as genuinely ethical only when they include some kind of direct moral consideration for extraterrestrial life. There are, I maintain, good reasons for the protection of space environments, including the protection of sites of interest to disciplines other than astrobiology. These reasons are no less ethical simply because their aim is something other than the protection of extraterrestrial life. While the possible existence of such reasons has been recognized, they have yet to be developed in a philosophically satisfying way. This paper aims to fill this lacuna by motivating and articulating an ethical perspective which recommends broader protection of the space environment. Long-range implications for such a broadening of planetary protection are considered, including implications for interstellar exploration.Scoma, A., Garrido-Amador, P., Nielsen, S.D., R?y, H., Kjeldsen, K.U., 2019. The polyextremophilic bacterium Clostridium paradoxum attains piezophilic traits by modulating its energy metabolism and cell membrane composition. Applied and Environmental Microbiology 85, e00802-19.: In polyextremophiles, i.e., microorganisms growing preferentially under multiple extremes, synergistic effects may allow growth when application of the same extremes alone would not. High hydrostatic pressure (HP) is rarely considered in studies of polyextremophiles, and its role in potentially enhancing tolerance to other extremes remains unclear. Here, we investigated the HP-temperature response in Clostridium paradoxum, a haloalkaliphilic moderately thermophilic endospore-forming bacterium, in the range of 50 to 70°C and 0.1 to 30?MPa. At ambient pressure, growth limits were extended from the previously reported 63°C to 70°C, defining C. paradoxum as an actual thermophile. Concomitant application of high HP and temperature compared to standard conditions (i.e., ambient pressure and 50°C) remarkably enhanced growth, with an optimum growth rate observed at 22?MPa and 60°C. HP distinctively defined C. paradoxum physiology, as at 22?MPa biomass, production increased by 75% and the release of fermentation products per cell decreased by >50% compared to ambient pressure. This metabolic modulation was apparently linked to an energy-preserving mechanism triggered by HP, involving a shift toward pyruvate as the preferred energy and carbon source. High HPs decreased cell damage, as determined by Syto9 and propidium iodide staining, despite no organic solute being accumulated intracellularly. A distinct reduction in carbon chain length of phospholipid fatty acids (PLFAs) and an increase in the amount of branched-chain PLFAs occurred at high HP. Our results describe a multifaceted, cause-and-effect relationship between HP and cell metabolism, stressing the importance of applying HP to define the boundaries for life under polyextreme conditions.Importance: Hydrostatic pressure (HP) is a fundamental parameter influencing biochemical reactions and cell physiology; however, it is less frequently applied than other factors, such as pH, temperature, and salinity, when studying polyextremophilic microorganisms. In particular, how HP affects microbial tolerance to other and multiple extremes remains unclear. Here, we show that under polyextreme conditions of high pH and temperature, Clostridium paradoxum demonstrates a moderately piezophilic nature as cultures grow to highest cell densities and most efficiently at a specific combination of temperature and HP. Our results highlight the importance of considering HP when exploring microbial physiology under extreme conditions and thus have implications for defining the limits for microbial life in nature and for optimizing industrial bioprocesses occurring under multiple extremes.Service, R.F., 2019. Quest for fire. Science 365, 18-21. McGinnis aims to use renewable energy to turn carbon dioxide and water into gasoline.On a warm March day here, you could almost mistake Rob McGinnis for a huckster newly arrived in a frontier town as he delivers a rapid-fire pitch to an audience of thousands of would-be investors. McGinnis, a chemical engineer and entrepreneur, isn't hawking snake oil, however: His elixir is gasoline. Nearly everyone in the developed world is hopelessly addicted to it. Collectively, we use nearly 3 trillion liters every year.At the pitch fair, McGinnis wears the Silicon Valley entrepreneur uniform of jeans, a black T-shirt, and black leather biker boots. On a theater-size stage, he delivers his spiel, sandwiched between 3-minute presentations for an online personalized clothing store and an outfit that would rent scooters by the month. “We make gasoline from air, water, and electricity,” McGinnis announces. “Today, gasoline sells for $3.50 a gallon in California. Next year, we will be selling it for $3 per gallon.” Other startups peddling ideas at the fair foresee markets in the billions, but McGinnis aims higher. “We're talking about a $2 trillion [per year] gasoline market,” he says.If all that sounds too good to be true, it might be. “I hope they're right,” says Olgica Bakajin, CEO of Porifera Inc., a San Leandro, California, company that has also worked on systems like those at the heart of McGinnis's fuelmaker. But she notes that McGinnis “is a good talker who sells things well.”He has convinced some powerful investors. In December 2018, he received $150,000 from Y Combinator, the Mountain View, California, seed funder hosting the pitch fair, to build a prototype of his air-to-gasoline–maker. The result was a refrigerator-size contraption of catalysts, tubes, electronics, and filters, assembled a week before the pitch fest.But before the demo, the machine sprang a leak. Although it wasn't operating at the pitch fest, McGinnis's optimism was. He promised audience members that the repaired device would extract carbon dioxide (CO2) from the air, add it to water, and use a catalyst to rearrange the chemical bonds to make hydrocarbons. The result: fossil fuel without the fossils. “It can sound like magic, but it's really just chemistry,” McGinnis told the audience.Synthesizing Gasoline, instead of refining it from oil, isn't a new idea. German chemists in the 1920s discovered they could turn coal into carbon monoxide (CO) and hydrogen—a combination known as synthesis gas. Catalysts, along with heat and pressure, could then transform synthesis gas into gasoline and other liquid hydrocarbons.But McGinnis's setup requires no heat, pressure, or coal. It uses only air, water, and electricity, which can come from the sun or wind. And with those renewable resources becoming ever cheaper, he's betting he can deliver gasoline more economically—and far more cleanly—than companies that must find oil, drill for it, ship it, and refine it.Several other startups and academic labs are pursuing the same dream. “There has been a lot of progress in the last few years” in turning CO2 into more-complex compounds, says Peidong Yang, a pioneer in the field at the University of California, Berkeley.Yet many of those efforts have stumbled over the expensive, energy-intensive steps needed to separate the hydrocarbons from the water they are produced in. Prometheus relies instead on a proprietary carbon nanotube membrane sieve that it says readily parts the hydrocarbons from water. “If they indeed have a low-energy separation process, that solves a big problem,” Yang says.“Rob's approach has a good chance of competing with fossil fuels,” says Matthew Eisaman, a physicist at the State University of New York in Stony Brook who consults for Prometheus. Eisaman ran a now-mothballed research program at Google's research arm, Google X, that aimed to turn the CO2 in seawater into liquid fuels.Bruce Hinds, a nanotube membrane expert at the University of Washington in Seattle, says McGinnis's published results on his separation technology inspire confidence that the approach could work. “I'm highly encouraged,” Hinds says.McGinnis has long defied expectations. After high school, he enlisted in the Navy, which sent him to Bahrain during the first Gulf War. There, he cleared mines from battlefields and harbors. “I didn't want to do it,” he says of his time in the service, but he needed money for school. He enrolled in Cabrillo College, a public community college near Santa Cruz, California, where he dreamed up an energy-efficient approach to desalinating water during a chemistry class. Today, most water desalination uses reverse osmosis, which employs energy to push water through a membrane that excludes salts. McGinnis planned instead to use forward osmosis, which relies on differences in the concentration of compounds on either side of a membrane to move water across; it consumes only about half as much energy. “I prototyped it in my kitchen,” he says. “I wanted something to distinguish myself to [transfer] to a really good school.”His school plan worked, and McGinnis moved to Yale University for his junior year. He majored in theater and focused on playwriting. “It was really good training,” he says. “A lot of what entrepreneurs do is tell stories.”But he never gave up on science. McGinnis canvassed the chemistry faculty to see whether anyone would let him use lab space in the evenings to pursue desalination. Menachem Elimelech, a Yale chemical engineer, agreed. McGinnis later pursued a Ph.D. in Elimelech's lab, constructed a forward osmosis demonstration, and helped launch a startup company called Oasys Water in Cambridge, Massachusetts, to commercialize the technology. Oasys built five large water treatment plants in China and was eventually bought out by its customer there.Even before the buyout, McGinnis felt sidelined from decision-making. He left Oasys in 2012 to explore other ideas for improving membranes for separations, initially looking for even better ways to purify water. He chose to pursue membranes made from thin plastic sheets shot through with myriad carbon nanotubes—tiny hollow tubes made entirely from carbon atoms. Researchers at Lawrence Livermore National Laboratory in California and elsewhere had shown that the tiny channels allow water to pass through while blocking other molecules. But the lab demonstrations employed dime-size membranes; larger membranes leaked and weren't uniform. “Carbon nanotube membranes never lived up to the hype,” says Jeffrey McCutcheon, a membrane separation expert at the University of Connecticut (UConn) in Storrs who collaborates with McGinnis.McGinnis thought he could solve the problem. He formed a company called MatterShift and received lab space in a startup incubator at UConn. After 5 years, he could make uniform membranes the size of a sheet of paper, consisting of carbon nanotubes embedded in a cheap commodity plastic called polyethersulfone.The key, McGinnis says, was figuring out how to align vast numbers of nanotubes—roughly 2.5 trillion per square meter—so that most pierce the membrane perpendicularly, as ion channels on a cell surface do. Some researchers have speculated that magnetic fields are key to the process, but McGinnis isn't saying. “It's our secret sauce,” he says.In March 2018, he, McCutcheon, and colleagues reported one possible use for their membranes in Science Advances: filtering out organic contaminants, such as odor-causing compounds, from water, while applying only a fraction of the pressure used to push water through reverse osmosis membranes. But McGinnis sees that use as a demonstration rather than his primary commercial target.In the past year, he and his team have come up with a way to transform their membranes from flat sheets into narrow hollow plastic fibers dotted with nanotube pores. The researchers can manufacture those fibers in a continuous process, McGinnis says, cutting them to any length and bundling them to make industrial filters.the nanotube filters can perform a far more important feat than removing contaminants, McGinnis says: They separate ethanol from water. Carbon nanotubes of the right diameter—about 1 nanometer—transport ethanol more quickly than water through their interior. McGinnis explains that ethanol's carbons have an affinity for the inside of the carbon nanotubes. So if the starting liquid contains at least 5% to 10% ethanol and a slight vacuum draws it through the filter, the alcohol molecules form a molecular conga line through the nanotubes, excluding nearly all water. The filtered solution winds up containing about 95% ethanol.McGinnis and his team haven't published those separation results yet. But researchers led by Yang Decai from Dalian University of Technology (DUT) in China reported in August 2018 in Nano Letters that a similar carbon nanotube membrane was highly selective and fast at separating ethanol and butanol (another alcohol) from water.If commercialized, such membranes could benefit biofuel companies that make ethanol from corn, McGinnis and others say. Fermentation leaves a solution of 10% ethanol in water. Today, ethanol producers use heat and 6-meter-tall distillation columns to boil off the ethanol, an energy-intensive process that costs about a third as much as the alcohol itself. McGinnis says his membranes could cut the distillation cost by 90% in an ethanol market worth $50 billion per year in the United States.If the membranes work as claimed, “That by itself would be big,” Peidong Yang says.McGinnis is working to prove that they do. Last year, MatterShift and partners at UConn received a $900,000 grant from the Department of Energy to demonstrate their ethanol separation technology. Their test uses a 2-meter-high tube with 1400 nanotube-pocked fibers, with results expected this summer.If either MatterShift's or DUT's membranes prove durable and long-lived, bioethanol producers should represent an eager market, says David Sholl, a chemical engineer at the Georgia Institute of Technology in Atlanta. McGinnis has already founded a company called MatterShift Biofuels to commercialize the technology. But he envisions a bigger future for his membranes: not just filtering ethanol fermented from corn or sugar, but also purifying fuel made from the air itself.Synthesizing the fuel is the easy part. Peidong Yang's team and groups at Oak Ridge National Laboratory (ORNL) in Tennessee and the University of Illinois in Urbana have published papers in the past 3 years showing that electricity and nanosize copper catalysts can turn CO2 and water into a mix of alcohols. And startups including a New Orleans, Louisiana, company called ReactWell are pursuing related approaches.Thus far, the ORNL team has reported the highest efficiency, turning 23% of the electrical energy into fuel. But all the groups using the approach to make alcohols face the challenge of separating the fuel from the water. McGinnis says his membranes are the answer. They are “the new piece in the puzzle no one else has.”In the air-to-fuel machine he hoped to demonstrate at Y Combinator, the membranes filter a liquid that flows from a meter-wide chamber containing two electrodes dunked in water. When air blows through the chamber, the CO2 it contains reacts with water, producing carbonic acid—the same molecule acidifying the oceans. That acid, in turn, reacts on a copper catalyst coating the negative electrode, or cathode, to create CO. The cathode also strips protons off water molecules, leaving behind negatively charged hydroxide ions. Those ions travel to a positively charged electrode, or anode, where they react to form water and oxygen gas. Meanwhile, at the cathode, multiple CO molecules and protons are transformed into ethanol and other alcohols.The result is the alcohol and water mixture that goes through the nanotube fibers. Prometheus has repaired its machine since the pitch fair, and it produces “a pretty steady drip” of fuel, McGinnis says: 10 milliliters per hour of alcohol that trickles out a red valve in the back. Over the next month, McGinnis and his colleagues plan to increase the size of their electrodes and catalysts to raise the production rate to 50 to 100 milliliters per hour.Ultimately, McGinnis plans to add a second catalytic step using commercially available catalysts called zeolites, which would convert the mix of alcohols to the larger hydrocarbon molecules found in gasoline. “All of the pieces of this process have been proved to work. But no one has put them all together,” he says. “Until now.” He expects the device, when optimized, to produce 20 liters of gasoline per week.Once the machine is working efficiently, electricity will make up about one-third of its operating costs. Renewable electricity prices around the globe are falling, however, and they already sink near zero at certain times of the day in places where the sun blazes or the wind howls. Prometheus, McGinnis says, could easily ramp its electricity demands up and down to take advantage of the lowest rates, and the machines could be sited wherever renewable power is cheapest. Next year, the company plans to build a $500,000 shipping container–size demonstration plant that can produce hundreds of thousands of liters of fuel per year. And last month, it inked its first deal, to begin to sell carbon-neutral fuel to Boom Supersonic, a Denver company building a supersonic commercial airliner.Even if all goes according to plan, McGinnis will face a long road to compete with the likes of ExxonMobil. He'll have to prove he can build a fuelmaker cheaply enough to make its gasoline affordable. That could be tough if turning it on makes sense only when renewable electricity prices bottom out. The fuelmaker also works only with a source of clean water. And before he can market his invention, he'll need to prove that his fuels can directly substitute for fossil-derived versions.At the pitch fair, McGinnis stands next to his prototype and repeats his story for a steady stream of potential investors. “We want to replace all fossil gasoline,” he says. “That would make the world a better place.” A few hours later, he loads up his wares and moves on in the hope that one day his dreams turn into an energy revolution.Shalygin, A.S., Kozhevnikov, I.V., Kazarian, S.G., Martyanov, O.N., 2019. Spectroscopic imaging of deposition of asphaltenes from crude oil under flow. Journal of Petroleum Science and Engineering 181, 106205. demonstrate, for the first time, the application of FTIR spectroscopic imaging approach in situ to monitor the precipitation process of oil asphaltenes, induced by n-heptane under flow using microfluidic devices. The aggregation of asphaltenes induced by n-heptane flow with subsequent precipitation and formation of the deposits was studied for solution containing 5?wt % of asphaltenes in benzene. The FTIR spectroscopic approach with an array detector allowed us to assess the spatial distribution of the chemical components and their amounts in the system and display the process of aggregates formation with a spatial resolution of few micrometres. This chemical imaging technique shows that the flow of heptane results in non-equilibrium condition when the local content of the flocculants reaches the threshold amount needed for the asphaltenes aggregation. The relatively slow process of heptane diffusion into the benzene induces the asphaltenes aggregation followed by their precipitation and compaction. Fast asphaltene aggregation process under heptane flow leads to the formation of the deposit firmly fixed to the surface, while the precipitates formed during the diffusion process of heptane into the benzene can be easily taken from the channel. The FTIR spectroscopic imaging of the deposits formed revealed the spatial inhomogeneity of the precipitated asphaltenes in the direction of the heptane flow in microfluidic channel which is reflected in their different chemical composition and the presence of different functional groups (CH2–CH3, C=O, S=O). In particular, it was found that asphaltenes of different types and different CH2/CH3 ratios gradually start to precipitate in the direction of n-heptane flow. The data obtained demonstrate the importance of local concentration of flocculants as well as local characteristics of the system for asphaltenes aggregation, and overall precipitation process in flow regime.Shao, K., Jiang, X., Hu, Y., Tang, X., Gao, G., 2019. Thaumarchaeota affiliated with Soil Crenarchaeotic Group are prevalent in the alkaline soil of an alpine grassland in northwestern China. Annals of Microbiology 69, 867-870.: Thaumarchaeota are key players within the global nitrogen cycle. Investigations of the Thaumarchaeota communities are important for an integrated understanding of nitrogen nutrient cycle in soil ecosystems. Therefore, the objective of this study was to examine the presence and diversity of Thaumarchaeota within an alkaline soil in the Bayinbuluke alpine grassland, China.Methods: The community DNAs were directly extracted from soil samples, collected on 15 July 2014, and paired-end V5–V6 amplicons of the 16S rRNA gene were sequenced by Illumina Miseq. Sequencing reads were processed using the Quantitative Insights Into Microbial Ecology (QIIME) v. 1.8.0 pipeline. After quality control, the validated sequence reads were classified into different operational taxonomic units (OTUs) based on a 97% identity level, using the Uclust algorithm to generate stable OTUs. The longest sequence in each cluster was chosen to be the representative sequence, and sequences were annotated using the Silva rRNA database project.Result: In the analyzed grassland soil, Thaumarchaeota had a relative abundance of 3.65 to 51.07% of the microbial community (mean?=?20.20%), representing the most dominant phylum. The thaumarchaeal community was dominated by the Soil Crenarchaeotic Group (SCG, 34.55 to 99.82%, mean?=?95.10%), with specifically low fraction of the ammonia-oxidizing genus Candidatus Nitrososphaera (2.83 to 30.37%, mean?=?13.10%) and remaining unclassified genus.Conclusion: Our results show Thaumarchaeota affiliated with SCG were prevalent in the alkaline soil of this grassland.Sheng, Q., Wang, G., Jin, N., Husein, M.M., Gao, J., 2019. Three-level structure change of asphaltenes undergoing conversion in a hydrogen donor solvent. Fuel 255, 115736. three-level structure of asphaltenes; including molecule unit, nanoaggregate, and cluster, undergoing hydrogenation in a hydrogen donor solvent was analyzed using proton nuclear magnetic resonance (1H NMR), X-ray diffraction (XRD), and small-angle X-ray scattering (SAXS). Upon conversion, the asphaltene molecule unit became more compact with shorter alkyl side chains. The nanoaggregate, consisting of an inner cylinder of polycyclic aromatic hydrocarbons (PAH) stacking and an outer cylinder engulfing the pendant alkyl chains, suffered a decrease in the radii of the outer and inner cylinders together with a decrease in the height of the concentric cylinders. The layer distance between the aromatic sheets (dm) of the nanoaggregate increased, whereas the average height of the aromatic sheet stack (Lc) and the number of aromatic sheets per nanoaggregate (N) decreased. The π-π interactions within the nanoaggregate structure were likely weakened by the hydrogen radicals. The top and/or the bottom aromatic sheets of the stacked structure were stripped upon hydrogenation and the weakening of the van der Waals interactions. Lastly, the cluster size initially decreased, owing to smaller size nanoaggregates and lesser extent of solvent swelling. For longer reaction times, however, the increase in aromaticity enabled higher extent of interaction among the nanoaggregates and resulted in an increase of the cluster size.Sheraz, S., Tian, H., Vickerman, J.C., Blenkinsopp, P., Winograd, N., Cumpson, P., 2019. Enhanced ion yields using high energy water cluster beams for secondary ion mass spectrometry analysis and imaging. Analytical Chemistry 91, 9058-9068. studies have shown that the use of a 20 keV water cluster beam as a primary beam for the analysis of organic and bio-organic systems resulted in a 10–100 times increase in positive molecular ion yield for a range of typical analytes compared to C60 and argon cluster beams. This resulted in increased sensitivity to important lipid molecules in the bioimaging of rat brain. Building on these studies, the present work compares 40 and 70 keV water cluster beams with cluster beams composed of pure argon, argon and 10%CO2, and pure CO2. First, as previously, we show that for E/nucleon about 0.3 eV/nucleon water and nonwater containing cluster beams generate very similar ion yields, but below this value, the water beams yields of BOTH negative and positive “molecular” ions increase, in many cases reaching a maximum in the <0.2 region, with yield increases of ～10–100. Ion fragment yields in general decrease quite dramatically in this region. Second, for water cluster beams at a constant E/nucleon, “molecular” ion yield increases with beam energy and hence cluster size due to increased sputter yield (ionization probability is constant). Third, as a consequence of the increased ion yield and the improved focusability using high-energy cluster beams, imaging in the 1 μm spatial resolution region is demonstrated on HeLa cells and rat brain tissue, monitoring molecules that were previously difficult to detect with other primary beams. Finally, the suggestion that the secondary ion emission zone has quasi-aqueous character seems to be sustained.Signorini, S.R., Mannino, A., Friedrichs, M.A.M., St-Laurent, P., Wilkin, J., Tabatabai, A., Najjar, R.G., Hofmann, E.E., Da, F., Tian, H., Yao, Y., 2019. Estuarine dissolved organic carbon flux from space: With application to Chesapeake and Delaware bays. Journal of Geophysical Research: Oceans 124, 3755-3778.: This study uses a neural network model trained with in situ data, combined with satellite data and hydrodynamic model products, to compute the daily estuarine export of dissolved organic carbon (DOC) at the mouths of Chesapeake Bay (CB) and Delaware Bay (DB) from 2007 to 2011. Both bays show large flux variability with highest fluxes in spring and lowest in fall as well as interannual flux variability (0.18 and 0.27 Tg C/year in 2008 and 2010 for CB; 0.04 and 0.09 Tg C/year in 2008 and 2011 for DB). Based on previous estimates of total organic carbon (TOCexp) exported by all Mid‐Atlantic Bight estuaries (1.2 Tg C/year), the DOC export (CB + DB) of 0.3 Tg C/year estimated here corresponds to 25% of the TOCexp. Spatial and temporal covariations of velocity and DOC concentration provide contributions to the flux, with larger spatial influence. Differences in the discharge of fresh water into the bays (74 billion m3/year for CB and 21 billion m3/year for DB) and their geomorphologies are major drivers of the differences in DOC fluxes for these two systems. Terrestrial DOC inputs are similar to the export of DOC at the bay mouths at annual and longer time scales but diverge significantly at shorter time scales (days to months). Future efforts will expand to the Mid‐Atlantic Bight and Gulf of Maine, and its major rivers and estuaries, in combination with coupled terrestrial‐estuarine‐ocean biogeochemical models that include effects of climate change, such as warming and CO2 increase.Plain Language Summary: This study combines satellite data, field work observations, and statistical and numerical models to investigate the seasonal and interannual variability of dissolved organic carbon (DOC) export from two major East Coast estuaries, Chesapeake, and Delaware Bays. DOC is a food supplement, supporting growth of microorganisms and plays an important role in the global carbon cycle through the microbial loop, a marine pathway which incorporates DOC into the food chain. Using this novel methodology, we were able to better quantify the combined contribution of these estuaries to the East Coast carbon budget and contrast estuarine properties affecting the DOC export, such as riverine inputs, time scales of variability, and geomorphology. The combined DOC contribution of these two estuaries represents 25% of the total organic carbon exported by all Mid‐Atlantic Bight (the coastal region running from Massachusetts to North Carolina) estuaries, and 27% of the total atmospheric carbon dioxide uptake in the Mid‐Atlantic Bight.Silva, M., Stray, H., Bj?rnstad, T., 2019. Stability assessment of PITT tracer candidate compounds – The case of pyrazines. Journal of Petroleum Science and Engineering 182, 106269. determination of the residual oil saturation (SOR) in the volumes swept between injector/producer well pairs is a parameter of major importance for the design and/or evaluation of IOR projects. The number of IOR projects is increasing with the growing number of mature oilfields. The partitioning inter-well tracer test (PITT) is used to measure SOR in waterflooded reservoirs and relies on the use of partitioning and passive tracers. Many PITT were unsuccessful in the past due to a poor knowledge about the compounds used as tracers and to date, very few compounds were developed for this application. New partitioning tracers are needed, and a systematic qualification process is necessary to reduce the risk of costly unsuccessful field tests. In the present document we report and discuss the findings from stability experiments performed on 2 alkylpyrazines, 1 methoxypyrazine, and 2 halogenated pyrazines under investigation for use as oil/water partitioning tracers for determination of the SOR in the inter-well region of water flooded oil reservoirs.The stability of 2,3-dimethylpyrazine, 2,6-dimethylpyrazine, 2-methoxypyrazine, 2-chloropyrazine, and 2-fluoropyrazine in brine solutions was evaluated in batch experiments at temperatures ranging from 25?°C to 150?°C for 12 weeks, at 3 different pH values and in the presence of typical oil reservoir rock materials (sandstone, carbonate rock, and clay). Results suggest that 2,3-dimethylpyrazine and 2,6-dimethylpyrazine possess the required stability and absence of significant interaction with the rock substrates. 2-chloropyrazine and 2-fluoropyrazine degrade with a temperature and pH dependent rate but are not influenced by the rock materials. 2-methoxypyrazine exhibits temperature dependent degradation in the absence of any rock substrate and in the presence of sandstone and carbonate rock. A strong interaction was observed between this compound and the clay material (kaolinite) which is responsible for dramatically increasing its degradation rate.Sivaram, C., Arun, K., Kiren, O.V., 2019. Alternative standard frequencies for interstellar communication. International Journal of Astrobiology 18, 209-210. 21 cm hydrogen line is considered a favourable frequency by the SETI programme in their search for signals from potential extraterrestrial (ET) civilizations. The Pioneer plaque, attached to the Pioneer 10 and Pioneer 11 spacecraft, portrays the hyperfine transition of neutral hydrogen and used the wavelength as a standard scale of measurement. Although this line would be universally recognized and is a suitable wavelength to look for radio signals from ETs, the presence of ubiquitous radiation from galactic hydrogen could make searches a little difficult. In this paper, we suggest several alternate standard frequencies, which are free of interference from atomic or molecular sources and is independent of any bias.Sivaram, C., Arun, K., Kiren, O.V., 2019. Bioenergetics and stellar luminosities. International Journal of Astrobiology 18, 211-212. draw attention to a curious coincidence wherein the most (steadily emitting) luminous objects in the Universe from stellar X-ray sources to ultra-luminous quasars and Ultra Luminous Infrared Galaxies, steadily emit a power per unit mass, which is just the same value as the maximal metabolic rate in (warm-blooded) bio-organisms.Smirnov, A., Qiu, Y., Jia, W., Walker, D.I., Jones, D.P., Du, X., 2019. ADAP-GC 4.0: Application of clustering-assisted multivariate curve resolution to spectral deconvolution of gas chromatography–mass spectrometry metabolomics data. Analytical Chemistry 91, 9069-9077. report a multivariate curve resolution (MCR)-based spectral deconvolution workflow for untargeted gas chromatography–mass spectrometry metabolomics. As an essential step in preprocessing such data, spectral deconvolution computationally separates ions that are in the same mass spectrum but belong to coeluting compounds that are not resolved completely by chromatography. As a result of this computational separation, spectral deconvolution produces pure fragmentation mass spectra. Traditionally, spectral deconvolution has been achieved by using a model peak approach. We describe the fundamental differences between the model peak-based and the MCR-based spectral deconvolution and report ADAP-GC 4.0 that employs the latter approach while overcoming the associated computational complexity. ADAP-GC 4.0 has been evaluated using GC–TOF data sets from a 27-standards mixture at different dilutions and urine with the mixture spiked in, and GC Orbitrap data sets from mixtures of different standards. It produced the average matching scores 960, 959, and 926 respectively. Moreover, its performance has been compared against MS-DIAL, eRah, and ADAP-GC 3.2, and ADAP-GC 4.0 demonstrated a higher number of matched compounds and up to 6% increase of the average matching score.Smith, N.W., Shorten, P.R., Altermann, E., Roy, N.C., McNabb, W.C., 2019. A mathematical model for the hydrogenotrophic metabolism of sulphate-reducing bacteria. Frontiers in Microbiology 10, 1652. doi: 10.3389/fmicb.2019.01652. bacteria (SRB) are studied across a range of scientific fields due to their characteristic ability to metabolise sulphate and produce hydrogen sulphide, which can lead to important consequences for human activities. Importantly, they are members of the human gastrointestinal microbial population, contributing to the metabolism of dietary and host secreted molecules found in this environment. The role of the microbiota in host digestion is well studied, but the full role of SRB in this process has not been established. Moreover, from a human health perspective, SRB have been implicated in a number of functional gastrointestinal disorders such as Irritable Bowel Syndrome and the development of colorectal cancer. To assist with the study of SRB, we present a mathematical model for the growth and metabolism of the well-studied SRB, Desulfovibrio vulgaris in a closed system. Previous attempts to model SRB have resulted in complex or highly specific models that are not easily adapted to the study of SRB in different environments, such as the gastrointestinal tract. We propose a simpler, Monod-based model that allows for easy alteration of both key parameter values and the governing equations to enable model adaptation. To prevent any incorrect assumptions about the nature of SRB metabolic pathways, we structure the model to consider only the concentrations of initial and final metabolites in a pathway, which circumvents the current uncertainty around hydrogen cycling by SRB. We parameterise our model using experiments with varied initial substrate conditions, obtaining parameter values that compare well with experimental estimates in the literature. We then validate our model against four independent experiments involving D. vulgaris with further variations to substrate availability. Further use of the model will be possible in a number of settings, notably as part of larger models studying the metabolic interactions between SRB and other hydrogenotrophic microbes in the human gastrointestinal tract and how this relates to functional disorders.Sobhani, Z., Al Amin, M., Naidu, R., Megharaj, M., Fang, C., 2019. Identification and visualisation of microplastics by Raman mapping. Analytica Chimica Acta 1077, 191-199., microplastics (MP) have emerged as global contaminants of serious concern to human and ecological health. However, identification and visualisation of MP are still a challenge, whether from wastewater, oceans, sediment or soil. Particularly when MP are mapped to visualise their distribution, the background signal from sediment and soil might be high and shield the MP signal from the analysis. Raman has recently received increasing attention, as the complementary spectrum of infrared (IR), because it can overcome the drawbacks of IR analysis including water interference, low lateral resolution and a complex spectrum. Here we show that Raman can identify and visualise MP from a soil/sand background, with almost no sample preparation, no dye, no destruction of the sample and no interference from water/organic matter/fluorescence background signals as well. By mapping image via their characteristic and fingerprint peaks, MP including polystyrene (PS), polyethylene terephthalate (PET), polyethylene (PE), polyvinyl chloride (PVC) and polypropylene (PP) can be individually identified and visualised. The lateral resolution along the focal plane is 1?μm/pixel to catch small MP down to 1?μm.Sobolev, A.V., Asafov, E.V., Gurenko, A.A., Arndt, N.T., Batanova, V.G., Portnyagin, M.V., Garbe-Sch?nberg, D., Wilson, A.H., Byerly, G.R., 2019. Deep hydrous mantle reservoir provides evidence for crustal recycling before 3.3 billion years ago. Nature 571, 555-559. strongly influences the physical properties of the mantle and enhances its ability to melt or convect. Its presence can also be used to trace recycling of surface reservoirs down to the deep mantle, which makes knowledge of the water content in the Earth's interior and its evolution crucial for understanding global geodynamics. Komatiites (MgO-rich ultramafic magmas) result from a high degree of mantle melting at high pressures and thus are excellent probes of the chemical composition and water contents of the deep mantle. An excess of water over elements that show similar geochemical behaviour during mantle melting (for example, cerium) was recently found in melt inclusions in the most magnesium-rich olivine in 2.7-billion-year-old komatiites from Canada and Zimbabwe. These data were taken as evidence for a deep hydrated mantle reservoir, probably the transition zone, in the Neoarchaean era?(2.8 to 2.5 billion years ago). Here we confirm the mantle source of this water by measuring deuterium-to-hydrogen ratios in these melt inclusions and present similar data for 3.3-billion-year-old komatiites from the Barberton greenstone belt. From the hydrogen isotope ratios, we show that the mantle sources of these melts contained excess water, which implies that a deep hydrous mantle reservoir has been present in the Earth's interior since at least the Palaeoarchaean era?(3.6 to 3.2 billion years ago). The reconstructed initial hydrogen isotope composition of komatiites is more depleted in deuterium than surface reservoirs or typical mantle but resembles that of oceanic crust that was initially altered by seawater and?then dehydrated during subduction. Together with an excess of chlorine and depletion of lead in the mantle sources of komatiites, these results indicate that seawater-altered?lithosphere recycling into the deep mantle, arguably by subduction, started before 3.3 billion years ago.Song, C., Wang, W., Liu, Z., Liu, Y., Cai, X., 2019. Development and application of two-dimensional liquid chromatography for the analysis of polycyclic aromatic sulfur heterocycles in heavy oil. Chinese Journal of Chromatography 37, 750-758. two-dimensional liquid chromatographic (2D LC) system was developed for the analysis of polycyclic aromatic sulfur heterocycles (PASHs) in heavy oil. The first dimension is a ligand-exchange chromatographic column packed with a palladium chloride/silica (PdCl2-SiO2) stationary phase, while the second dimension is a Spherisorb-NH2 column. The PASHs in vacuum gas oil were enriched online, and polycyclic aromatics hydrocarbons (PAHs) were separated according to their aromatic ring numbers. These separated fractions were analyzed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and detailed molecular characterization of PASHs and PAHs was achieved. Typical molecular structures of PASHs and PAHs in these fractions could be provided, and the side chain as well as the core structures were predicted. It is significant for the feedstocks selection and optimization of the hydrodesulfurization process by using these molecular characterization information.Souza, J.F.L., Santos, M.D., Magalh?es, R.M., Neto, E.M., Oliveira, G.P., Roque, W.L., 2019. Automatic classification of hydrocarbon “leads” in seismic images through artificial and convolutional neural networks. Computers & Geosciences 132, 23-32. paper aims to provide alternative approaches for automatic classification of subsurface hydrocarbon-bearing regions from 2D seismic images driven by multi-layer perceptron neural networks (MLPs) (a kind of artificial neural network) and convolutional neural networks (CNNs). The first approach is based on a standard MLP whose features are controlled by Haralick’s textural descriptors; the second one is developed with a multiple-layer CNN. Both techniques are studied to identify geologic “leads”, instead of delineating other structures of the porous medium, such as salt bodies or seismic faults. The outcomes obtained from each approach are evaluated for a dataset of seismic images corresponding to the offshore SEAL Basin in Brazil’s northeastern. Performance indicators (accuracy, recall, precision, F-measure and loss) are computed to verify training and validation of the network learning capabilities. It is shown that for both MLP and CNN configurations, good agreement is achieved in blind testing qualitatively and quantitatively.Speltini, A., Pastore, M., Merlo, F., Maraschi, F., Sturini, M., Dondi, D., Profumo, A., 2019. Humic acids pyrolyzed onto silica microparticles for solid-phase extraction of benzotriazoles and benzothiazoles from environmental waters. Chromatographia 82, 1275-1283. work focuses on the extraction and determination of contaminants of environmental concern belonging to the classes of benzotriazoles and benzothiazoles from tap and raw river water samples. The sorbent, recently proposed by this research group, prepared by pyrolysis of humic acids (HAs) onto silica microparticles (HA-C@silica), was tested for fixed-bed SPE of benzotriazole and benzothiazole compounds by modulating its sorption affinity through the carbon loading. This was successfully increased from 10 to 20?wt% HAs and the obtained material, characterized by different techniques, provided quantitative adsorption at the sample native pH (7.5–8), for 50–250?mL samples spiked with each compound at the micrograms per litre levels. After extraction, the analytes were simultaneously desorbed by 4?mL methanol, even more reducible to small volume before HPLC–HESI-MS/MS analysis. Recovery was satisfactory for all compounds, ranging from 70 to 114%, with RSD values?≤?16% (n?=?3). The developed procedure allows quantitation of benzotriazoles at concentrations far below the environmental trigger limits. HA-C@silica turned out to be appealing in comparison with the commercial sorbents in terms of cost, recovery and pre-concentration for determination of such pollutants in actual surface waters. Good reproducibility was observed on independent HA-C@silica preparations.Spencer, R.G.M., Kellerman, A.M., Podgorski, D.C., Macedo, M.N., Jankowski, K., Nunes, D., Neill, C., 2019. Identifying the molecular signatures of agricultural expansion in Amazonian headwater streams. Journal of Geophysical Research: Biogeosciences 124, 1637-1650. impacts on aquatic ecosystems are well studied; however, most research has focused on temperate regions, whereas the forefront of agricultural expansion is currently in the tropics. At the vanguard of this growth is the boundary between the Amazon and Cerrado biomes in Brazil, driven primarily by expansion of soybean and corn croplands. Here we examine the impacts of cropland expansion on receiving lowland Amazon Basin headwater streams in terms of dissolved organic carbon (DOC) concentration and dissolved organic matter (DOM) composition via ultrahigh-resolution mass spectrometry. Streams draining croplands had lower DOC concentrations and DOM molecular signatures enriched in N- and S-containing formula in comparison to forested streams. Cropland streams were also enriched in aliphatic, peptide-like, and highly unsaturated and phenolic (low O/C) compound categories in comparison to forest streams (enriched in polyphenolics, condensed aromatics, and highly unsaturated and phenolic [high O/C] compound categories) indicative of the shifting of sources from organic-rich surface soils and litter layers to autochthonous and more microbial biomass. Distinct molecular assemblages were strongly correlated with cropland and forest catchments, highlighting headwater streams as sentinels for detecting change. On investigation of unique molecular formulae present in only cropland sites, four cropland markers provided the ability to track agricultural impacts in the region. Overall, these patterns indicate reduced organic matter inputs in croplands and greater microbial degradation at these sites leading to declining DOC concentrations, and DOM of more microbial character in receiving streams that is more biolabile, with clear ramifications for downstream ecology and biogeochemical cycles.Stevens, A.H., McDonald, A., de Koning, C., Riedo, A., Preston, L.J., Ehrenfreund, P., Wurz, P., Cockell, C.S., 2019. Detectability of biosignatures in a low-biomass simulation of martian sediments. Scientific Reports 9, 9706. of a remnant habitable environment by the Mars Science Laboratory in the sedimentary record of Gale Crater has reinvigorated the search for evidence of martian life. In this study, we used a simulated martian mudstone material, based on data from Gale Crater, that was inoculated and cultured over several months and then dried and pressed. The simulated mudstone was analysed with a range of techniques to investigate the detectability of biosignatures. Cell counting and DNA extraction showed a diverse but low biomass microbial community that was highly dispersed. Pellets were analysed with bulk Elemental Analysis – Isotope Ratio Mass Spectrometry (EA-IRMS), high-resolution Laser-ablation Ionisation Mass Spectrometry (LIMS), Raman spectroscopy and Fourier Transform InfraRed (FTIR) spectroscopy, which are all techniques of relevance to current and future space missions. Bulk analytical techniques were unable to differentiate between inoculated samples and abiotic controls, despite total levels of organic carbon comparable with that of the martian surface. Raman spectroscopy, FTIR spectroscopy and LIMS, which are high sensitivity techniques that provide chemical information at high spatial resolution, retrieved presumptive biosignatures but these remained ambiguous and the sedimentary matrix presented challenges for all techniques. This suggests?challenges for detecting definitive evidence for life, both in the simulated lacustrine environment via standard microbiological techniques and in the simulated mudstone via analytical techniques with relevance to robotic missions. Our study suggests that multiple co-incident high-sensitivity techniques that can scan the same micrometre-scale spots are required to unambiguously detect biosignatures, but the spatial coverage of these techniques needs to be high enough not to miss individual cellular-scale structures in the matrix.Stevenson, D.S., 2019. Evolutionary Exobiology II: investigating biological potential of synchronously-rotating worlds. International Journal of Astrobiology 18, 362-376. that orbit M-class dwarf stars in their habitable zones are expected to become tidally-locked in the first billion years of their history. Simulations of potentially habitable planets orbiting K and G-class stars also suggest that many will become tidally-locked or become pseudo-synchronous rotators in a similar time frame where certain criteria are fulfilled. Simple models suggest that such planets will experience climatic regions organized in broadly concentric bands around the sub-stellar point, where irradiation is maximal. Here, we develop some of the quantitative, as well as the qualitative impacts of such climate on the evolutionary potential of life on such worlds, incorporating the effects of topography and ocean currents on potential biological diversity. By comparing atmospheric circulation models with terrestrial circulation and biological diversity, we are able to construct viable thought models of biological potential. While we await the generation of atmospheric circulation models that incorporate topography and varying subaerial landscape, these models can be used as a starting point to determine the overall evolutionary potential of such worlds. The planets in these thought-models have significant differences in their distribution of habitability that may not be apparent from simple climate modelling.Stevenson, D.S., 2019. Niche amplitude, tidal-locking and Fermi's Paradox. International Journal of Astrobiology 18, 377-383.‘Where is everybody?’ remarked Enrico Fermi, leading to the famous, and as yet unanswered ‘Fermi's Paradox’ as this remark has come to be known. While there are a number of possible solutions that vary from the distances are too great; the cost prohibitive or civilizations naturally decline or eliminate themselves before interstellar travel becomes possible, none of these are intellectually satisfying. More recently, Manasvi Lingam and Abraham Loeb suggested that for those planets orbiting red dwarfs, atmospheric erosion may be a partial solution to this ‘paradox’. Such planets may experience greater exposure to stellar winds and/or extreme ultraviolet and X-radiation (henceforth abbreviated to EUV). While this proposition is undeniably reasonable, it is likely incomplete. A more fundamental limitation on the development of biological complexity is imposed by plate tectonics: time. On asynchronously rotating planets, the habitable area for any species is defined by latitudinal bands that encompass the globe. Conversely, on synchronous rotators, the comparative habitable area is limited to broadly concentric regions surrounding the Sub-Stellar Point (SSP). Given that terrestrial mammals and from them humans evolved in tropical or subtropical regions, the geographical area subtended with these conditions is likely to be smaller and transected by suitable landmasses for shorter periods than on asynchronously rotating worlds. Habitable subaerial regions for individual species are therefore more limited in area. This leads to a greater limitation on the temporal intervals over which biological complexity can evolve.Stevenson, D.S., Large, S., 2019. Evolutionary exobiology: towards the qualitative assessment of biological potential on exoplanets. International Journal of Astrobiology 18, 204-208. planet may be defined as habitable if it has an atmosphere and is warm enough to support the existence of liquid water on its surface. Such a world has the basic set of conditions that allow it to develop life similar to ours, which is carbon-based and has water as its universal solvent. While this definition is suitably vague to allow a fairly broad range of possibilities, it does not address the question as to whether any life that does form will become either complex or intelligent. In this paper, we seek to synthesize a qualitative definition of which subset of these ‘habitable worlds’ might develop more complex and interesting life forms. We identify two key principles in determining the capacity of life to breach certain transitions on route to developing intelligence. The first is the number of potential niches a planet provides. Secondly, the complexity of life will reflect the information density of its environment, which in turn can be approximated by the number of available niches. We seek to use these criteria to begin the process of placing the evolution of terrestrial life in a mathematical framework based on environmental information content. This is currently testable on Earth and will have clear application to the worlds that we are only beginning to discover. Our model links the development of complex life to the physical properties of the planet, something which is currently lacking in all evolutionary theory.Strack, M., Hayne, S., Lovitt, J., McDermid, G.J., Rahman, M.M., Saraswati, S., Xu, B., 2019. Petroleum exploration increases methane emissions from northern peatlands. Nature Communications 10, 2804. are globally significant sources of atmospheric methane (CH4). In the northern hemisphere, extensive geologic exploration activities have occurred to map petroleum deposits. In peatlands, these activities result in soil compaction and wetter conditions, changes that are likely to enhance CH4 emissions. To date, this effect has not been quantified. Here we map petroleum exploration disturbances on peatlands in Alberta, Canada, where peatlands and oil deposits are widespread. We then estimate induced CH4 emissions. By our calculations, at least 1900?km2 of peatland have been affected, increasing CH4 emissions by 4.4–5.1?kt?CH4?yr?1 above undisturbed conditions. Not currently estimated in Canada’s national reporting of greenhouse gas (GHG) emissions, inclusion would increase current emissions from land use, land use change and forestry by 7–8%. However, uncertainty remains large. Research further investigating effects of petroleum exploration on peatland GHG fluxes will allow appropriate consideration of these emissions in future peatland management.Straka, L.L., Meinhardt, K.A., Bollmann, A., Stahl, D.A., Winkler, M.-K.H., 2019. Affinity informs environmental cooperation between ammonia-oxidizing archaea (AOA) and anaerobic ammonia-oxidizing (Anammox) bacteria. The ISME Journal 13, 1997-2004. ammonia-oxidizing (Anammox) bacteria (AnAOB) rely on nitrite supplied by ammonia-oxidizing bacteria (AOB) and archaea (AOA). Affinities for ammonia and oxygen play a crucial role in AOA/AOB competition and their association with AnAOB. In this work we measured the affinity constants for ammonia and oxygen (half-saturation; km) of two freshwater AOA enrichments, an AOA soil isolate (N. viennensis), and a freshwater AnAOB enrichment. The AOA enrichments had similar kinetics (μmax ≈ 0.36 d?1, km,NH4 ≈ 0.78??M, and km,O2 ≈ 2.9??M), whereas N. viennensis had similar km values but lower μmax (0.23 d?1). In agreement with the current paradigm, these AOA strains showed a higher affinity for ammonia (lower km,NH4; 0.34–1.27??M) than published AOB measurements (>20??M). The slower growing AnAOB (μmax ≈ 0.16 d?1) had much higher km values (km,NH4 ≈ 132??M, km,NO2 ≈ 48??M) and were inhibited by oxygen at low levels (half-oxygen inhibition; ki,O2 ≈ 0.092??M). The higher affinity of AOA for ammonia relative to AnAOB, suggests AOA/AnAOB cooperation is only possible where AOA do not outcompete AnAOB for ammonia. Using a biofilm model, we show that environments of ammonia/oxygen counter diffusion, such as stratified lakes, favors this cooperation.Struck, J., Bliedtner, M., Strobel, P., Schumacher, J., Bazarradnaa, E.n., Zech, R., 2019. Leaf wax n-alkane pattern and compound-specific δ13C of plants and topsoils from semi-arid Mongolia. Biogeosciences Discussions 2019, 1-23. pattern and their compound-specific δ13C signatures are valuable proxies for paleoenvironmental reconstructions. So far, their potential has not been investigated in semi-arid to arid regions. We have therefore analysed the leaf wax n-alkanes and their compound-specific δ13C of five plant species (Poaceae, Cyperaceae, Artemisia spp., Caragana spp. and Larix sp.), and topsoils (0–5?cm) along two transects in central and southern Mongolia. Grasses depict a distinct dominance of the n-C31 homologue, whereas Caragana spp. and Artemisia spp. are dominated by n-C29. Larix sp. is characterized by the mid-chain n-alkanes n-C23 and n-C25. From plant to soil, n-alkane homologue pattern show the potential to differentiate between grass covered sites from those covered by Caragana spp. n-Alkane concentrations and OEP values of the topsoils are distinctly influenced by mean annual temperature, mean annual precipitation and aridity, likely reflecting the degree of n-alkane degradation and biomass production. In contrast, the n-alkane average chain-length and the n-alkane ratio (n-C31?/?n-C29?+?n-C31) are not affected by climatic parameters. The compound-specific δ13C signatures are strongly corelated to climate, showing a significant enrichment with increasing aridity, indicating the effect of water use efficiency. Our calibration results suggest that long-chain n-alkanes and their compound-specific δ13C signatures have great potential to reconstruct paleoenvironmental and -climatic conditions when used in sediment archives from Mongolia.Stuckman, M.Y., Lopano, C.L., Berry, S.M., Hakala, J.A., 2019. Geochemical solid characterization of drill cuttings, core and drilling mud from Marcellus Shale energy development. Journal of Natural Gas Science and Engineering 68, 102922. tons of drill cuttings generated from shale gas development are currently disposed of in landfills, buried in-situ, or reused as road fill. Cuttings, core samples and operating drilling mud from the Marcellus Shale Energy and Environmental Laboratory in WV were studied to better characterize drill cuttings and to evaluate trace metal mobility in various disposal environments. Results showed that physical and chemical properties of drill cuttings are impacted by the host-rock formation, calcium sources and the residual drilling-mud. Barite in residual drilling mud forms a coating around rock cuttings and influences the mobility of Sr in drill cuttings. Trace metals in drill cuttings are primarily associated with pyrite and total organic carbon (TOC) phases in the shale. Based on sequential extraction results, various trace metal mobilities are controlled by additional solid fractions in drill cuttings, such as pyrite, TOC, calcite, barite and exchangeable clays in the shale.Stüeken, E.E., 2019. Ancient rust. Nature Geoscience 12, 498-499. that banded iron formations record oxic conditions during deposition is established, as a model demonstrates that they are formed of primary iron oxides rather than secondarily altered silicate minerals.Banded iron formations — the world’s major source of iron ore today — are one of the great enigmas in geology. Made of interlaminated microcrystalline quartz and iron-rich minerals (commonly iron oxides), they are most often found in 1.8 to 3.0 billion-year-old sedimentary rock units. They have not formed since the mid-Precambrian and are thus essentially an extinct lithology. Geologists have tried for decades to develop plausible models for their formation, which has proven to be challenging because modern analogues are extremely rare1. Writing in Nature Geoscience, Robbins et al.2 present a hydrogeological box model to address a recent concern that the iron oxides within these deposits could have formed via secondary processes. They conclude that banded iron formations are most likely primary precipitates of the early ocean and therefore record oxic conditions on the early Earth.The oceans and atmosphere of the Archaean eon, more than 2.5 billion years ago, are thought to have been devoid of free oxygen3. Banded iron formations are perhaps the largest oxidized surface reservoir preserved from this anoxic world, which poses a geochemical conundrum. Early studies suggested that the iron oxides in banded iron formations were primary features, formed by photochemical oxidation of hydrothermally sourced dissolved iron (Fe2+) in the surface ocean4,5. This process would have been facilitated by the absence of an ozone shield3. In contrast, more recent work concluded that photochemical mechanisms may have been too inefficient, and that banded iron formations are instead relics of the activity of photoferrotrophic bacteria6. Alternatively, banded iron formations may record transient occurrences of dissolved biogenic oxygen, which subsequently oxidized hydrothermally sourced iron in the upper water column7. Although the exact mechanism for the production of primary iron oxides is not yet resolved, their occurrence long before the rise of atmospheric oxygen some 2.3 billion years ago would imply a large supply of oxidizing power to the marine biosphere8.Beyond their implications for early oxidation, banded iron formations (Fig. 1) are also important archives of the composition of Precambrian seawater. Their contents of rare-earth elements9, transition metals10,11, and phosphorus12 have been used to constrain seawater pH, hydrothermal fluxes, the intensity of oxidative weathering, micronutrient supplies, and microbial biochemistry. These inferences build upon the premise that banded iron formations represent primary, oxidized, chemical sediments that captured environmental conditions from the time of deposition.However, this premise has been questioned. Some petrographic and experimental data suggest that banded iron formations were actually deposited as primary or very early diagenetic ferrous silicate minerals, in particular greenalite13,14. If so, the iron oxides that are present today must have formed by oxidizing groundwaters that penetrated sediment packages long after the time of deposition. If this is correct, banded iron formations cannot be used as archives of environmental information about the early ocean. This proposition would not only demand a reinterpretation of existing trace element records but would also challenge widely held views about the evolving Precambrian ocean and its biosphere.Faced by these competing interpretations, Robbins et al. reassess the formation of oxic banded iron formations in an anoxic world. They developed a hydrogeological box model to test if basin-scale circulation of oxidizing groundwaters could plausibly explain the large amounts of iron oxides that are preserved in the early Precambrian record. They considered a range of parameters, including the permeability of sediments, hydraulic gradients, dissolved-oxygen contents, and iron abundance in over 3.8 million possible permutations. Parameters were optimized for the Hamersley Basin in Western Australia, where banded iron formations formed between 2.6 and 2.45 billion years ago. Robbins and colleagues estimate that secondary oxidation by fluids — if it occurred — may have extended over a period of up to 250 million years in this basin. However, only 9% of the model runs resulted in large-scale iron oxidation within this timeframe, and these particular model runs used a combination of rather unrealistic input values. The authors therefore conclude that the iron oxides contained in banded iron formations are a primary precipitate of the early ocean. Occurrences of greenalite may thus be relics of localized diagenetic Fe3+ reduction that was perhaps restricted to a particular facies.Undoubtedly, the calculations presented by Robbins et al. put some burden of proof back on those who argue for primary greenalite formation but have so far not presented a basin-scale mechanism for secondary iron oxidation. On the other hand, the implausibility of basin-wide secondary oxidation of greenalite to iron oxides does not explain away the observation that greenalite is the first mineral to form in Archaean seawater experiments14. Resolving these conflicting ideas may warrant closer inspection of the rock record.The remaining disputes over the conditions of banded iron formation deposition are ultimately centred around the question of how extensive the reduced and oxidized iron phases are in any given basin. Detailed structural and mineralogical mapping of banded iron formations and associated sediments on a regional scale may go a long way in advancing this debate.References1. Chi Fru, E. et al. Solid Earth 9, 573–598 (2018).2. Robbins, L. J. et al. Nat. Geosci. (2019).3. Lyons, T. W., Reinhard, C. T. & Planavsky, N. J. Nature 506, 307–315 (2014).4. Anbar, A. D. & Holland, H. D. Geochim. Cosmochim. Acta 56, 2595–2603 (1992).5. Isley, A. E. & Abbott, D. H. J. Geophys. Res.: Solid Earth 104, 15461–15477 (1999).6. Konhauser, K. O. et al. Geology 30, 1079–1082 (2002).7. Chan, C. S., Emerson, D. & Luther, G. W. III Geobiology 14, 509–528 (2015).8. Kipp, M. A. & Stüeken, E. E. Sci. Adv. 3, eaao4795 (2017).9. Viehmann, S., Bau, M., Hoffmann, J. E. & Münker, C. Precambrian Res. 270, 165–180 (2015).10. Konhauser, K. O. et al. Nature 458, 750–753 (2009).11. Swanner, E. D. et al. Earth Planet. Sci. Lett. 390, 253–263 (2014).12. Planavsky, N. J. et al. Nature 467, 1088–1090 (2010).13. Rasmussen, B., Muhling, J. R. & Fischer, W. W. Geology 47, 167–170 (2019).14. Tosca, N. J., Guggenheim, S. & Pufahl, P. K. Geol. Soc. Am. Bull. 128, 511–530 (2016).Su, E., Liang, Y., Zou, Q., Niu, F., Li, L., 2019. Analysis of effects of CO2 injection on coalbed permeability: Implications for coal seam CO2 sequestration. Energy & Fuels 33, 6606-6615. proper understanding of permeability reductions of CH4-containing coal seams after CO2 injection is essential, as coal permeability is the key parameter influencing the efficiency of enhanced coalbed methane recovery with CO2 sequestration and theoretical research on it is lacking. The main objective of this study was to accurately quantify the effects of CO2 injection on coalbed permeability. Therefore, permeability decrease coefficients and permeability rebound and recovery pressures of a binary gas (CH4 + CO2) are proposed based on the Shi–Durucan and extended Langmuir models. Then, the trends of these parameters under the influence of the main influencing factors are detailed. Specifically, the permeability decrease coefficient increased with an increase in CO2 proportion and increased rapidly when the reservoir gas pressure was low. Permeability recovery pressure decreased with an increase in CO2 proportion; the range of decrease was larger at low CO2 proportions. CO2 proportion had little effect on the permeability rebound pressure. Besides, the larger the Langmuir volume constant of CO2, the larger was the permeability decrease coefficient and permeability rebound pressure, and the smaller the permeability recovery pressure. However, the effect of the Langmuir pressure constant on these parameters was relatively weak. Finally, in light of these results, the implications of different characteristics of permeability evolution for CO2 injection pressure adjustment in the process of enhanced coalbed methane recovery with CO2 sequestration are discussed from a macroscopic perspective. The results of this study may provide a reference to select appropriate coal seams and injection pressures for CO2 sequestration.Sugihara, S., Shibata, M., Mvondo Ze, A.D., Tanaka, H., Kosaki, T., Funakawa, S., 2019. Forest understories controlled the soil organic carbon stock during the fallow period in African tropical forest: a 13C analysis. Scientific Reports 9, 9835. organic carbon (SOC) dynamics after slash-burn agriculture are poorly understood in African tropical forest, though recent studies have revealed C4 grass invasion as a forest understory influences SOC dynamics after deforestation. This study aimed to quantify the relative SOC contribution of C4 and C3 plants separately through the sequential fallow periods of forest (cropland, or 4–7, 20–30, or >50 years of fallow forest) in the tropical forest of eastern Cameroon. We evaluated the SOC stock and natural 13C abundance for each layer. The SOC stock was largest in 4–7 years fallow forest (136.6?±?8.8 Mg C ha?1; 100?cm depth, and C4:C3?=?58:42), and decreased with increasing fallow period. SOC from C4 plants was larger in the 4–7 and 20–30 years fallow forests (57.2–60.4?±?5.8 Mg C ha?1; 100?cm depth), while it clearly decreased in >50 years fallow forest (35.0?±?4.1 Mg C ha?1; 100?cm depth), resulting in the smallest SOC in this mature forest (106.4?±?12.9 Mg C ha?1; 100?cm depth). These findings indicate that C4 grass understories contributed to the SOC restoration during early fallow succession in the tropical forest of eastern Cameroon.Sui, Y., Huang, C., Zhang, R., Wang, Z., Ogg, J., 2019. Astronomical time scale for the middle-upper Doushantuo Formation of Ediacaran in South China: Implications for the duration of the Shuram/Wonoka negative δ13C excursion. Palaeogeography, Palaeoclimatology, Palaeoecology 532, 109273. Ediacaran Period (635–541?Ma) of the Neoproterozoic records the advent of multi-cellular life on Earth. The Ediacaran Doushantuo Formation (DST Fm) contains records of some phases of this bio-evolution and profound perturbations to the global carbon cycle, but the timing and the duration of these events are still unclear. The Jiulongwan (JLW) roadcut in South China is a well-studied reference section for these Ediacaran events, including the major EN3 (Shuram/Wonoka) negative carbon-isotope excursion. Spectral analysis of geochemical data through the middle-upper DST Fm indicates that the sedimentary cycles correspond to 405-kyr long-eccentricity and ~100?kyr short-eccentricity periods. Tuning the DST Fm at JLW section to the 405-kyr long-eccentricity cycles yielded a ~30?Myr-long astronomical time scale. Member DST-4 (black shale) of the uppermost DST Fm spans 7.5?Myr and the negative δ13C excursion (EN3/Shuram/Wonoka) has a duration of~20?Myr. Relative to a U-Pb date of 551.1?±?0.7?Ma near the top of the DST Fm, the onset of Member DST-4 is at 557.8?±?0.8?Ma, and the projected basal age of Member DST-3 is 579.3?±?0.8?Ma. The onsets of positive EP2 and negative EN3 δ13C excursions were ca. 578.1?Ma and 571.1?Ma, respectively; therefore, both excursions occurred after the termination of the Gaskiers glaciation (~581?Ma). Thereby, these ages and astronomical time scale provide important new constraints on the subdivision of Ediacaran strata, and have implications for our understanding the character of the δ13C excursions. Orbital forcing may be important to the co-evolution of life, the global carbon cycle and sedimentary environments.Suicmez, V.S., 2019. Feasibility study for carbon capture utilization and storage (CCUS) in the Danish North Sea. Journal of Natural Gas Science and Engineering 68, 102924. innovative addition to the conventional oil and gas extraction by introducing enhanced oil recovery (EOR) techniques in the Danish North Sea is something which has been sought for long time. Combining the offshore EOR technology with the carbon capture and storage (CCS) is considered to be a possibly attractive solution as the associated benefit is twofold: (1) increased oil recovery through miscible displacement via CO2 pushing the hydrocarbons out of the reservoir and (2) the disposal of a greenhouse gas such as the CO2. A feasibility study for implementing a carbon capture, storage and utilization (CCUS) project is presented in the scope of this study, in a North Sea Chalk Field which is the oldest and one of the largest oilfields in the Danish sector, both for the technical and the economic merit, by means of using a commercial reservoir simulation package. The capital (CAPEX) and operational (OPEX) expenditures associated with such a long term development project is estimated. Results suggest that around 100 million barrels of additional oil reserves can be unlocked via CO2 injection, while 40 million tones of CO2 is being trapped in the reservoir.Sun, C., Zhang, Y., Alessi, D.S., Martin, J.W., 2019. Nontarget profiling of organic compounds in a temporal series of hydraulic fracturing flowback and produced waters. Environment International 131, 104944. fracturing (HF) flowback and produced water (FPW) can be toxic to aquatic life but its chemical content is largely unknown, variable and complex. Seven FPW samples were collected from a HF operation in the Duvernay Formation (Alberta, Canada) over 30?days of flowback and characterized by a nontarget workflow based on high performance liquid chromatography - high resolution mass spectrometry (HRMS). A modified Kendrick mass defect plot and MS/MS spectral interpretation revealed seven series of homologues composed of ethylene oxide (i.e. -CH2CH2O-), among which a series of aldehydes was proposed as degradation products of polyethylene glycols, and two series of alkyl ethoxylate carboxylates could be proprietary HF additives. Many other ions were confidently assigned a formula by accurate mass measurement and were subsequently prioritized for identification by matching to records in ChemSpider and the US EPA's CompTox Chemistry Dashboard. Quaternary ammonium compounds, amine oxides, organophosphorous compounds, phthalate diesters and hydroxyquinoline were identified with high confidence by MS/MS spectra (Level 3), matching to reference spectra in MassBank (Level 2) or to authentic standards (Level 1). Temporal trends showed that most of the compounds declined in abundance over the first nine days of flowback, except for phthalate diesters and hydroxyquinoline that were still observed on Day 30 and had disappearance half-lives of 61 and 91?days, respectively. All the compounds followed first-order disappearance kinetics in flowback, except for polyoxygenated acids which followed second-order kinetics. This analysis and the workflow, based largely on public on-line databases, enabled profiling of complex organic compounds in HF-FPW, and will likely be useful for further understanding the toxicity and chemical fate of HF-FPW.Sun, L., Tuo, J., Zhang, M., Wu, C., Chai, S., 2019. Impact of water pressure on the organic matter evolution from hydrous pyrolysis. Energy & Fuels 33, 6283-6293. oil and gas, as an important part to make up the energy-deficient. A series of breakthroughs had been made in their exploration and development in the past few years. However, the effects of deep fluids during hydrocarbon formation and evolution are still an ambiguous problem. Therefore, to investigate the effect of water pressure (PW) on hydrocarbon generation and thermal evolution of type-I, type-II, and type-III kerogens in a deeper stratum, three series of pyrolysis experiments were conducted on three samples with different kerogen types (types II1, I, and III in TC, YMS, and XJ samples, respectively) in a high-temperature, high-pressure simulator. The type-I kerogen was pyrolyzed with 5, 20, 35, 50, 65, and 80 MPa water pressure at 375 °C for 48 h, whereas the type-II and type-III kerogens were pyrolyzed with 10, 20, 30, 40, 50, and 60 MPa water pressure at 350 °C for 48 h. The results showed that there was a threshold pressure PW affecting liquid hydrocarbons. In addition, before the threshold pressure, PW played a role in promoting, but then it was the inhibiting. For gaseous hydrocarbons, while the pressure effects and results were the same as with liquid hydrocarbons in TC samples under the near-critical or critical state, they had no obvious effects in YMS and XJ samples before the critical state, which proved that the organic matter (OM) evolution was associated with the state of fluid in the reaction system and the effects were stronger when the fluid was under the near-critical or critical state than when it is not under this state. The reasons could be concluded as follows: (1) the different properties of water, as the ionization product constant of water (K(w)) was higher in TC samples and may provide more H+ to participate in the OM reactions compared to YMS and XJ samples. Moreover, the particular characteristics of intersolubility with organic solvent occurred under near-critical or critical states, resulting in the more water-soluble hydrocarbons being expelled in TC samples. (2) Chemical mechanism: based on the first-order reaction equation for oil–gas generation and essential characters of samples and experiments, it can be concluded that the influence degree of PW on OM evolution was related to the type of OM, the thermal maturity as well as the nature of water. (3) Physical mechanism: the vapor in free space and generated hydrocarbons in pores were in a dynamic balance state, which also resulted in the existence of threshold pressure PW affecting OM evolution. Therefore, understanding the effects of PW on OM evolution would help us to study the oil–gas generation accurately in actual geology and help preferably in oil–gas exploration and exploitation.Sun, Q., Fu, Z., Finlay, R., Lian, B., 2019. Transcriptome analysis provides novel insights into the capacity of the ectomycorrhizal fungus Amanita pantherina to weather K-containing feldspar and apatite. Applied and Environmental Microbiology 85, e00719-19.: Ectomycorrhizal (ECM) fungi, symbiotically associated with woody plants, markedly improve the uptake of mineral nutrients such as potassium (K) and phosphorus (P) by their host trees. Although it is well known that ECM fungi can obtain K and P from soil minerals through biological weathering, the mechanisms regulating this process are still poorly understood at the molecular level. Here, we investigated the transcriptional regulation of the ECM fungus Amanita pantherina in weathering K-containing feldspar and apatite using transcriptome sequencing (RNA-seq) and validated these results for differentially expressed genes using real-time quantitative PCR. The results showed that A. pantherina was able to improve relevant metabolic processes, such as promoting the biosynthesis of unsaturated fatty acids and steroids in the weathering of K-containing feldspar and apatite. The expression of genes encoding ion transporters was markedly enhanced during exposure to solid K-containing feldspar and apatite, and transcripts of the high-affinity K transporter ApHAK1, belonging to the HAK family, were significantly upregulated. The results also demonstrated that there was no upregulation of organic acid biosynthesis, reflecting the weak weathering capacity of the A. pantherina isolate used in this study, especially its inability to utilize P in apatite. Our findings suggest that under natural conditions in forests, some ECM fungi with low weathering potential of their own may instead enhance the uptake of mineral nutrients using their high-affinity ion transporter systems.Importance: In this study, we revealed the molecular mechanism and possible strategies of A. pantherina with weak weathering potential in the uptake of insoluble mineral nutrients by using transcriptome sequencing (RNA-seq) technology and found that ApHAK1, a K transporter gene of this fungus, plays a very important role in the acquisition of K and P. Ectomycorrhizal (ECM) fungi play critical roles in the uptake of woody plant nutrients in forests that are usually characterized by nutrient limitation and in maintaining the stability of forest ecosystems. However, the regulatory mechanisms of ECM fungi in acquiring nutrients from minerals/rocks are poorly understood. This study investigated the transcriptional regulation of A. pantherina weathering K-containing feldspar and apatite and improves the understanding of fungal-plant interactions in promoting plant nutrition enabling increased productivity in sustainable forestry.Sun, X., Kostka, J.E., 2019. Hydrocarbon-degrading microbial communities are site specific, and their activity is limited by synergies in temperature and nutrient availability in surface ocean waters. Applied and Environmental Microbiology 85, e00443-19.: The objective of this study was to quantify the potential for hydrocarbon biodegradation in surface waters of three sites, representing geographic regions of major oil exploration (Beaufort Sea in the Arctic, northern Gulf of Mexico [GOM], and southern GOM), in a systematic experimental design that incorporated gradients in temperature and the availability of major nutrients. Surface seawater was amended in microcosms with Macondo surrogate oil to simulate an oil slick, and microcosms were incubated, with or without nutrient amendment, at temperatures ranging from 4 to 38?C. Using respiration rate as a proxy, distinct temperature responses were observed in surface seawater microcosms based on geographic origin; biodegradation was nearly always more rapid in the Arctic site samples than in the GOM samples. Nutrient amendment enhanced respiration rates by a factor of approximately 6, stimulated microbial growth, and generally elevated the taxonomic diversity of microbial communities within the optimal temperature range for activity at each site, while diversity remained the same or was lower at temperatures deviating from optimal conditions. Taken together, our results advance the understanding of how bacterioplankton communities from different geographic regions respond to oil perturbation. A pulsed disturbance of oil is proposed to favor copiotrophic r-strategists that are adapted to pointed seasonal inputs of phytoplankton carbon, displaying carbon and nutrient limitations, rather than oil exposure history. Further understanding of the ecological mechanisms underpinning the complex environmental controls of hydrocarbon degradation is required for improvement of predictive models of the fate and transport of spilled oil in marine environments.Importance: The risk of an oil spill accident in pristine regions of the world’s oceans is increasing due to the development and transport of crude oil resources, especially in the Arctic region, as a result of the opening of ice-free transportation routes, and there is currently no consensus regarding the complex interplay among the environmental controls of petroleum hydrocarbon biodegradation for predictive modeling. We examined the hydrocarbon biodegradation potential of bacterioplankton from three representative geographic regions of oil exploration. Our results showed that rates of aerobic respiration coupled to hydrocarbon degradation in surface ocean waters are controlled to a large extent by effects of temperature and nutrient limitation; hydrocarbon exposure history did not appear to have a major impact. Further, the relationship between temperature and biodegradation rates is linked to microbial community structure, which is specific to the geographic origin.Sun, Y., Feng, F., Nie, B., Cao, J., Zhang, F., 2019. High throughput identification of pentacyclic triterpenes in Hippophae rhamnoides using multiple neutral loss markers scanning combined with substructure recognition (MNLSR). Talanta 205, 120011. fast and simple analytical method was developed to fully understand the chemical diversity of pentacyclic triterpenes: lupane, oleanane and ursane type, using multiple neutral loss markers scanning combined with substructure recognition (MNLSR). This procedure was performed on ultra-high performance liquid chromatography coupled to electrospray ionization quadrupole Orbitrap high resolution mass spectrometry (UHPLC/ESI Q-Orbitrap). Hippophae rhamnoides was used as an example. This approach includes three systematic workflows: (i) targeted identification of 25 reference standards in order to deduce the mechanism of fragmentation in both positive and negative modes. (ii) statistical analysis for neutral loss markers and structural fragment markers of pentacyclic triterpenes by fragmentation mechanism information. (iii) untargeted identification using multiple neutral loss markers scanning technique to discover new compounds and then confirming structural characterization by structural fragment markers. This mass spectra data analysis approach was successful to identify and confirm 15 new compounds from Hippophae rhamnoides samples. This study extended the application of mass spectrometry to satisfy the requirements of high-throughput identification for pentacyclic triterpenes in new medicine or food resources and could help chemists rapidly discover novel similar substructure compounds from a complex matrix.Sun, Y., Ma, X., Guo, W., Jia, R., Li, B., 2019. Numerical simulation of the short- and long-term production behavior of the first offshore gas hydrate production test in the South China Sea. Journal of Petroleum Science and Engineering 181, 106196. hydrate-bearing sediments at the first offshore gas hydrate production test site in the Shenhu area, South China Sea, have the characteristics of high irreducible water saturation and low permeability. The stratum structure of this production test site is complex, its gas hydrate-bearing layer (GHBL), three-phase layer (TPL) and free gas layer (FGL) all contain methane gas or gas hydrates, that make the production more complicated. According to the available geological data at the first offshore gas hydrate production test site in the Shenhu area, a 2D numerical simulation model is built to study the short- and the long-term production behavior of the gas hydrates in the Shenhu area. In the short-term, the total gas production from hydrates, when the TPL gas saturation is 0.078, is determined to be 2.75?×?105?m3, which is close to the actual total gas production of 3.09?×?105?m3. When the irreducible water saturation varies from 0.40 to 0.63, the total gas production changes from 1.41?×?105 to 2.75?×?105?m3, and the total water production decreases from 1.04?×?104 to 8.7?×?103?m3, which indicates that irreducible water is a favorable factor for gas production from hydrates in clayey silt sediments. In the long-term gas production from hydrates, the gas production rate first decreases, then increases, and finally decreases again. Gas hydrate reformation occurs at the interface between the TPL and the FGL, which will adversely affect the gas production from hydrates.Suneel, V., Rao, V.T., Suresh, G., Chaudhary, A., Vethamony, P., Ratheesh, R., 2019. Oil pollution in the eastern Arabian Sea from invisible sources: A multi-technique approach. Marine Pollution Bulletin 146, 683-695. Eastern Arabian Sea (EAS) is affected by oil pollution, as often evidenced by the presence of tarballs along the West Coast of India (WCI). Tarball samples collected during May 2017 along the Goa coast were subject to biomarker fingerprints, and the results matched with Bombay High (BH) oil fingerprints. The present study primarily aims at identifying the potential minor spill areas using Sentinel-imagery. Interestingly, repeated occurrence of oil spills detected at two locations, perfectly matched with BH platforms. The simulated Lagrangian trajectories also depict that tarball particles have originated from those detected locations. In 2017 alone, the quantity of spilled oil was estimated to be 129,392?l. However, spills detected offshore regions of Kachchh and Mangalore were found to be caused by ships. This is the first comprehensive study, tracking the oil pollution sources in the EAS through multi-technique approach - chemical, remote sensing and numerical modeling.Susanti, D., Frazier, M.C., Mukhopadhyay , B., 2019. A genetic system for Methanocaldococcus jannaschii: An evolutionary deeply rooted hyperthermophilic Methanarchaeon. Frontiers in Microbiology 10, 1256. doi: 10.3389/fmicb.2019.01256. deeply rooted methanogens belonging to the genus of Methanocaldococcus living in deep-sea hydrothermal vents derive energy exclusively from hydrogenotrophic methanogenesis, one of the oldest respiratory metabolisms on Earth. These hyperthermophilic, autotrophic archaea synthesize their biomolecules from inorganic substrates and perform high temperature biocatalysis producing methane, a valuable fuel and potent greenhouse gas. The information processing and stress response systems of archaea are highly homologous to those of the eukaryotes. For this broad relevance, Methanocaldococcus jannaschii, the first hyperthermophilic chemolithotrophic organism that was isolated from a deep-sea hydrothermal vent, was also the first archaeon and third organism for which the whole genome sequence was determined. The research that followed uncovered numerous novel information in multiple fields including those described above. M. jannaschii was found to carry ancient redox control systems, precursors of dissimilatory sulfate reduction enzymes, and a eukaryotic-like protein translocation system. It provided a platform for structural genomics and tools for incorporating unnatural amino acids into proteins. However, the assignments of in vivo relevance to these findings or interrogations of unknown aspects of M. jannaschii through genetic manipulations remained out of reach, as the organism remained genetically intractable. This report presents tools and methods that remove this block. It is now possible to knockout or modify a gene in M. jannaschii and genetically fuse a gene with an affinity tag sequence, thereby allowing facile isolation of a protein with M. jannaschii-specific attributes. These tools have helped to genetically validate the role of a novel coenzyme F420-dependent sulfite reductase in conferring resistance to sulfite in M. jannaschii and to demonstrate that the organism possesses a deazaflavin-dependent system for neutralizing oxygen.Szabó-Tugyi, N., V?r?s, L., V.-Balogh, K., Botta-Dukát, Z., Bernát, G., Schmera, D., Somogyi, B., 2019. Aerobic anoxygenic phototrophs are highly abundant in hypertrophic and polyhumic waters. FEMS Microbiology Ecology 95, fiz104. anoxygenic phototrophs (AAPs) are a group of photoheterotrophic bacteria common in natural waters. Here, AAP abundance and contribution to total bacterial abundance and biomass were investigated to test whether the trophic status of a lake or content of coloured dissolved organic matter (CDOM) play a role in determining AAP distribution and abundance in shallow inland lakes, with special focus on hypertrophic and polyhumic waters. Twenty-six different shallow lakes in Hungary were monitored. AAP abundance and biomass were determined by epifluorescence microscopy. The lakes exhibit a broad range of CDOM (2–7000 mg Pt L?1) and phytoplankton biomass (2–1200 μg L?1 chlorophyll a concentration). Very high AAP abundance (up to 3 × 107 cells mL?1) was observed in polyhumic and hypertrophic shallow lakes. AAP abundance was influenced by phytoplankton biomass and CDOM content, and these effects were interrelated. As determined, 40 μg L?1 chlorophyll a and 52 mg Pt L?1 CDOM are threshold levels above which these effects have a synergistic relationship. Hence, the observed high AAP abundance in some soda pans is a consequence of combined hypertrophy and high CDOM content. AAP contribution was influenced by total suspended solids (TSS) content: the success of AAP cells could be explained by high TSS levels, which might be explained by the decrease of their selective grazing control.Tammekivi, E., Vahur, S., Keki?ev, O., van der Werf, I.D., Toom, L., Herodes, K., Leito, I., 2019. Comparison of derivatization methods for the quantitative gas chromatographic analysis of oils. Analytical Methods 11, 3514-3522. The determination of fatty acid composition using quantitative gas chromatographic (GC) analysis is a common method of characterizing fats and oils. A wide variety of derivatization methods have been developed to enable the GC analysis of non-volatile oil components. However, there has been no systematic comparison of these derivatization procedures in truly quantitative terms, i.e. with absolute amounts of fatty acids, not just ratios. In this paper, for the first time, a comprehensive quantitative comparison of four derivatization methods is presented: (1) m-(trifluoromethyl)phenyltrimethylammonium hydroxide (TMTFTH) methylation, (2) two-step derivatization with sodium ethoxide (NaOEt) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), (3) two-step derivatization with KOH and BSTFA and (4) acid-catalyzed methylation (ACM). The comparison of the results obtained with both a mass spectrometric (MS) detector and a flame ionization detector (FID) is mainly based on derivatization efficiency (absolute quantification) and intermediate precision (within-lab reproducibility) over several weeks. The overall results indicate that out of the four examined methods the TMTFTH derivatization was the least work-intensive and the most accurate – both in terms of reproducibility and derivatization efficiency.Tan, S., Liu, J., Fang, Y., Hedlund, B.P., Lian, Z.-H., Huang, L.-Y., Li, J.-T., Huang, L.-N., Li, W.-J., Jiang, H.-C., Dong, H.-L., Shu, W.-S., 2019. Insights into ecological role of a new deltaproteobacterial order Candidatus Acidulodesulfobacterales by metagenomics and metatranscriptomics. The ISME Journal 13, 2044-2057. abundant but yet uncultivated bacterial groups exist in extreme iron- and sulfur-rich environments, and the physiology, biodiversity, and ecological roles of these bacteria remain a mystery. Here we retrieved four metagenome-assembled genomes (MAGs) from an artificial acid mine drainage (AMD) system, and propose they belong to a new deltaproteobacterial order, Candidatus Acidulodesulfobacterales. The distribution pattern of Ca. Acidulodesulfobacterales in AMDs across Southeast China correlated strongly with ferrous iron. Reconstructed metabolic pathways and gene expression profiles showed that they were likely facultatively anaerobic autotrophs capable of nitrogen fixation. In addition to dissimilatory sulfate reduction, encoded by dsrAB, dsrD, dsrL, and dsrEFH genes, these microorganisms might also oxidize sulfide, depending on oxygen concentration and/or oxidation reduction potential. Several genes with homology to those involved in iron metabolism were also identified, suggesting their potential role in iron cycling. In addition, the expression of abundant resistance genes revealed the mechanisms of adaptation and response to the extreme environmental stresses endured by these organisms in the AMD environment. These findings shed light on the distribution, diversity, and potential ecological role of the new order Ca. Acidulodesulfobacterales in nature.Tang, J., Xu, Y., Wang, G., Huang, J., Han, W., Yao, Z., Zhu, Z., 2019. Methane in soil gas and its migration to the atmosphere in the Dawanqi oilfield, Tarim Basin, China. Geofluids 2019, 1693746. microseepage is the result of natural gas migration from subsurface hydrocarbon accumulations to the Earth’s surface, and it is quite common in hydrocarbon-prone basins. In this study, by analyzing gas concentrations and isotope composition of soil gas, the potentials of CH4 gas transferred to the surface were studied at three measurement transects in Dawanqi oilfield, Tarim Basin, China. It was found that CH4 from deep-buried reservoirs could migrate upwards to the surface through faults, fissures, and permeable rocks, during which some CH4 was oxidized and the unoxidized methane remained in the soil or was emitted into the atmosphere. Soil gas samples had mean concentrations of 907.1, 62.3, 21.7, 11.0, and 5.8?ppmv for CH4, C2H6, C3H8, C4H10, and C5H12, respectively. The C1/C2+ (13.3 for soil gas and 3.75 for absorbed gas) and gas wetness ratio (12% for soil gas and 26% for absorbed gas) suggested that the hydrocarbons were derived from a thermogenic process. According to isotope composition analysis, the δ13CCO2, δ13CCH4, and δDCH4 values for the soil gas from Dawanqi oilfield varied from -15.5 to -17.2‰, -11‰ to -17‰, and -150 to -189‰, respectively. The extreme 13C enrichment in CH4 is possibly because of the fractionation effects of diffusional migration and methanotrophic oxidation. Soil gas and absorbed gas showed high CH4 concentrations at the edge of the fault block, which indicated that fault was conductive to gas migration. Also, gas migrated from the surface to the atmosphere in the center region of the fault block because of the high permeability and shallow depth of the reservoir in Dawanqi oilfield.Tang, Q., Wan, B., Yuan, X., Muscente, A.D., Xiao, S., 2019. Spiculogenesis and biomineralization in early sponge animals. Nature Communications 10, 3348. sponges have biomineralized spicules. Molecular clocks indicate sponge classes diverged in the Cryogenian, but the oldest spicules are Cambrian in age. Therefore, sponges either evolved spiculogenesis long after their divergences or Precambrian spicules were not amenable to fossilization. The former hypothesis predicts independent origins of spicules among sponge classes and?presence of transitional forms with weakly biomineralized spicules, but this prediction has not been tested using paleontological data. Here, we report an early Cambrian sponge that, like several other early Paleozoic sponges, had weakly biomineralized and hexactine-based siliceous?spicules with large axial filaments and high organic proportions. This material, along with Ediacaran microfossils containing putative non-biomineralized axial filaments, suggests that Precambrian sponges may have had weakly biomineralized spicules or lacked them altogether, hence their poor record. This work provides a new search image for Precambrian sponge fossils, which are critical to resolving the origin of sponge?spiculogenesis and biomineralization.Tang, Y., Li, D., Cao, D., Xu, W., 2019. Extracting biomolecule collision cross sections from FT-ICR mass spectral line shape. Talanta 205, 120093. extend the ion structure analysis capability of Fourier transform mass spectrometry (FT-MS), both time-domain and frequency-domain methods have been developed to extract ion collision cross sections (CCS) from high resolution mass spectra in Fourier transform ion cyclotron resonance (FT-ICR) cells. In this study, a new frequency-domain method, namely the line shape fitting method, was proposed to calculate ion CCSs from FT-ICR mass spectra line shape. Besides experimental data, simulated data with precisely controlled signal to noise levels and decay factors were also applied to characterize this method. Compared with the linewidth correction method previously proposed by our group, this line shape fitting method is more tolerant to noise, data length, and sampling rate, thus providing more consistent results. More importantly, CCS measurements of angiotensin I, bradykinin, ubiquitin and cytochrome c show that the resolving power is improved with the new method.Tannous, J.H., de Klerk, A., 2019. Asphaltenes formation during thermal conversion of deasphalted oil. Fuel 255, 115786. asphaltenes are formed during the thermal conversion of heavy oil. When new asphaltenes are formed from deasphalted oil, it erodes the conversion advantage provided by solvent deasphalting prior to visbreaking. The postulate that asphaltenes formation is caused by free radical addition reactions was evaluated. Indene was employed to exacerbate asphaltenes formation during thermal conversion of deasphalted oil at 400?°C. Evidence was provided that indene was involved in addition reactions with itself and with deasphalted oil to produce new n-pentane insoluble material. Whether indene induced increase asphaltenes formation, or whether it formed addition products with the deasphalted oil was not resolved. Self-reaction of indene at 400?°C resulted in extensive formation of n-pentane insoluble material. Formation of n-pentane insoluble material was reduced in mixtures with indane and naphthalene. Using these model systems the presence and nature of addition products was determined. The reported thermal conversion of indene was consistent with reaction chemistry based on molecule-induced homolysis, free radical addition, and propagation / termination by hydrogen transfer. The prevalence of addition reactions and the importance of hydrogen transfer reactions were highlighted, which have implications for modelling reaction chemistry describing thermal conversion of heavy oil.Tao, K., Cao, J., Chen, X., Nueraili, Z., Hu, W., Shi, C., 2019. Deep hydrocarbons in the northwestern Junggar Basin (NW China): Geochemistry, origin, and implications for the oil vs. gas generation potential of post-mature saline lacustrine source rocks. Marine and Petroleum Geology 109, 623-640. (>4500?m) sedimentary units in petroliferous basins are a frontier field for petroleum exploration and exploitation worldwide. This study focuses on the northwestern Junggar Basin of NW China and presents the results of a comprehensive geochemical analysis of the source rocks and hydrocarbons hosted by deep reservoirs in this region, including data obtained from Rock-Eval pyrolysis, carbon isotope, biomarker, and light hydrocarbon analyses. These data provide insights into the exploration potential of deep hydrocarbons in the study area and in other areas with similar geologic settings (i.e., saline lacustrine petroleum systems). Results indicate that the deep hydrocarbons in the northwestern Junggar Basin are dominated by oil, with both the oil and natural gas being derived mainly from the lower Permian Fengcheng Formation. This formation was deposited in a heterogeneous saline lacustrine environment, which led to the generation of geochemically diverse oil compositions. Consequently, Fengcheng-derived oils can be divided into subcategories based on source rock lithology; i.e., hypersaline alkaline muddy dolomites, saline (dolomitic) mudstones, and brackish mudstones. A small number of deep oils in the study area were derived from the Carboniferous–lower Permian Jiamuhe Formation. The deep hydrocarbons in the study area generally accumulated in near-source environments, indicating that prospective areas are present in the form of Fengcheng-derived oils in the depocenter of the Mahu sag, especially oils derived from hypersaline alkaline muddy dolomites and saline (dolomitic) mudstones. These source rocks are likely to have generated oil even under the highly mature conditions associated with deep burial. This might explain why discoveries within saline lacustrine basins are generally dominated by oil, implying that these conditions might also exist within the deeper parts of saline lacustrine basins worldwide.Tarhan, L.G., Hood, A.V.S., Droser, M.L., Gehling, J.G., Briggs, D.E.G., Gaines, R.R., Robbins, L.J., Planavsky, N.J., 2019. Petrological evidence supports the death mask model for the preservation of Ediacaran soft-bodied organisms in South Australia: Comment. Geology 47, e473. et al. (2019) recently petrographically analyzed several samples of the fossiliferous Ediacara Member of South Australia and reported ironoxide grain coatings, framboidal structures, and iron staining, which they interpret as the oxidized remnants of Ediacaran pyrite. They posit that precipitation of pyrite preceded that of the authigenic silica cements previously interpreted to have played a critical role in facilitating the moldic preservation of the soft-bodied Ediacara Biota (Tarhan et al., 2016). Liu et al. discount a role for silica cementation, arguing that the previously proposed ‘death mask’ model of fossilization mediated by pyrite veneers (Gehling, 1999) offers a more compelling explanation for the preservation of Ediacara Member fossils. High dissolved silica concentrations in the Precambrian and early Paleozoic oceans appear to have mediated several modes of fossilization, including Bitter Springs–type preservation, silica replacement, silica cementation, and precipitation of authigenic clay phases. These taphonomic processes, along with pyritization, phosphatization, carbonate-associated and carbonaceous preservation, have provided an exceptional window into Ediacaran ecosystems. There is no single mode of Ediacaran fossilization, but compelling evidence for the death mask model still awaits development. Comment on: Liu, A.G., McMahon, S., Matthews, J.J., Still, J.W., and Brasier, A.T., 2019, Petrological evidence supports the death mask model for the preservation of Ediacaran soft-bodied organisms in South Australia: Geology, v. 47, p. 215– 218, . Reply to Comment: Liu, A.G., McMahon, S., Matthews, J.J., Still, J.W., Brasier, A.T., Marosi, D., 2019. Petrological evidence supports the death mask model for the preservation of Ediacaran soft-bodied organisms in South Australia: Reply. Geology 47, e474-e474.Telus, M., Alexander, C.M.O.D., Hauri, E.H., Wang, J., 2019. Calcite and dolomite formation in the CM parent body: Insight from in situ C and O isotope analyses. Geochimica et Cosmochimica Acta 260, 275-291. constrain the conditions of aqueous alteration in early planetesimals, we carried out in situ C and O isotope analyses of calcite and dolomite and O isotope analyses of magnetite from the highly altered CM chondrites ALH 83100, ALH 84034, and MET 01070. Petrographic and isotopic analyses of these samples support previous findings of multiple generations of carbonate growth. We observe wide ranges in the C and O isotope compositions of carbonates of up to 80‰ and 30‰, respectively, that span the full range of previously reported bulk carbonate values for CM chondrites. Variations in the Δ17O values indicate that fluid evolution varied for each chondrite. ALH 83100 dolomite-magnetite δ18O fractionation of 23‰?±?7‰ (2SD) corresponds to dolomite formation temperature of 125?°C?±?60?°C. δ13C vs δ18O values fall into two groups, one consisting of primary calcite and the other consisting of dolomite and secondary calcite. The positive correlation between δ13C and δ18O for primary calcite is consistent with the precipitation of calcite in equilibrium with a gas mixture of CO (or CH4) and CO2. The isotopic composition of calcite in CM1s and CM2s overlap significantly; however, many CM1 calcite grains are more depleted in δ18O compared to CM2s. Altogether, the data indicate that the fluid composition during calcite formation was initially the same for both CM1s and CM2s. CM1s experienced more episodes of carbonate dissolution and reprecipitation where some fraction of the carbonate grains survive each episode resulting in a highly disequilibrium assemblage of carbonates on the thin-section scale.Tian, X., Zhang, Y., Zhuo, Q., Yu, Z., Guo, Z., 2019. Tight oil charging characteristics of the Lower Permian Fengcheng Formation in Mahu sag, Junggar Basin: evidence from fluid inclusions in alkaline minerals. Acta Petrolei Sinica 40, 646-659. oil-bearing strata and reservoirs of tight oil in Mahu sag, Junggar Basin are the Lower Permian Fengcheng Formation. Aiming at the special alkaline minerals developed in Fengcheng Formation, this study explores the accumulation evolutionary process of tight oil and the effect of alkaline minerals on the enrichment of tight oil. Through the petrographic observation, scanning electron microscopy, X-ray diffraction, laser Raman spectroscopy and fluid inclusion analysis, three types of fluid inclusions have been identified in four alkaline minerals (wegscheiderite, shortite, eitelite and reedmergnerite) and magnesites in Fengcheng Formation. The first type is the primary fluid inclusions in alkaline minerals (including primary heavy oil inclusions, bitumen inclusions and primary aqueous inclusions), wherein the primary aqueous inclusions have a homogenization temperature of 70-110℃. The second type is the secondary fluid inclusion in alkaline minerals (including secondary medium oil inclusions and secondary aqueous inclusions), wherein the secondary aqueous inclusions have a homogenization temperature of 100-110℃. The third type is the primary light oil inclusions in the magnesite. In combination with the burial history, thermal evolution history and hydrocarbon generation history, it is believed that the accumulation of tight oil in Mahu sag is completed as promoted by both alkaline mineral formation and fracture activity, and the oil charging process can be divided into three stages. Influenced by rapid burial of early strata and high paleogeotherm, the Late Permian is the heavy oil charging stage. The organic matters of Fengcheng Formation have entered into the hydrocarbon generation threshold. The resulting heavy oil is accompanied by the promotion of fluid exchange during the formation of alkaline minerals, thus forming the small-scale enrichment. The Early Triassic is the medium oil charging stage. Organic matters at this time are in the mature stage, and a large amount of medium-sized oil is generated along active faults and fissures into adjacent reservoirs. The Early Jurassic is a light oil charging stage. Due to the influence of hydrothermal fluids in some areas, the temperature of source rocks continues to rise, organic matters enter the high mature stage, and a small amount of light oil is enriched under fault activity and fluid exchange during the formation of magnesite.Toner, J.D., Catling, D.C., 2019. Alkaline lake settings for concentrated prebiotic cyanide and the origin of life. Geochimica et Cosmochimica Acta 260, 124-132. plays a critical role in origin of life hypotheses that have received strong experimental support from cyanide-driven synthesis of amino acids, nucleotides, and lipid precursors. However, relatively high cyanide concentrations are needed. Such cyanide could have been supplied by reaction networks in which hydrogen cyanide in early Earth’s atmosphere reacted with iron to form ferrocyanide salts, followed by thermal decomposition of ferrocyanide salts to cyanide. Using an aqueous model supported by new experimental data, we show that sodium ferrocyanide salts precipitate in closed-basin, alkaline lakes over a wide range of plausible early Earth conditions. Such lakes were likely common on the early Earth because of chemical weathering of mafic or ultramafic rocks and evaporative concentration. Subsequent thermal decomposition of sedimentary sodium ferrocyanide yields sodium cyanide (NaCN), which dissolves in water to form NaCN-rich solutions. Thus, geochemical considerations newly identify a particular geological setting and NaCN feedstock nucleophile for prebiotic chemistry.Torrado, L., Carvajal-Arenas, L.C., Sanchez, J., Mann, P., Silva-Tamayo, J.C., 2019. Late Cretaceous–Cenozoic sequence stratigraphic and paleogeographic controls on petroleum system elements of the Nicaraguan platform, western Caribbean Sea. American Association of Petroleum Geologists 103, 1925-1962. Cretaceous–to–present-day mixed carbonate–clastic deposition along the Nicaraguan platform, western Caribbean Sea, has evolved from a tectonically controlled, rifted upper Eocene shallow–to–deep-marine carbonate–siliciclastic shelf to an upper Miocene–to–present-day tectonically stable shallow-marine carbonate platform and passive margin. By integrating subsurface data of 287 two-dimensional seismic lines and 27 wells, we interpret the Cenozoic stratigraphic sequence as 3 cycles of transgression and regression beginning with an upper Eocene rhodolitic–algal carbonate shelf that interfingered with marginal siliciclastic sediments derived from exposed areas of Central America bordering the margin to the west. During the middle Eocene, a carbonate platform was established with both rimmed reefs and isolated patch reefs. A late Eocene forced regression produced widespread erosion and subaerial exposure across much of the platform and was recorded by a regional unconformity. The Oligocene–upper Miocene sedimentary record includes a southeastward prograding delta of the proto-Coco river, which drained the emergent area of what is now northern Nicaragua. The late Miocene–to–present-day period marks a period of strong subsidence with the development of small pinnacle reefs. We describe favorable petroleum system elements of the Nicaraguan platform that include (1) Eocene fossiliferous limestone source rocks documented as thermally mature in vintage exploration wells and seen as active gas chimneys emanating from inferred carbonate reservoirs; (2) upper–to–middle Eocene reservoirs in patch and pinnacle reefs, middle Eocene calcareous slumps, and Oligocene fluvial-deltaic facies documented in wells; and (3) regional seal intervals that consist of both regional unconformities and Eocene–Oligocene intraformational shale.Tremblay, J., Fortin, N., Elias, M., Wasserscheid, J., King, T.L., Lee, K., Greer, C.W., 2019. Metagenomic and metatranscriptomic responses of natural oil degrading bacteria in the presence of dispersants. Environmental Microbiology 21, 2307-2319. biodegradation has been extensively studied in the wake of the Deepwater Horizon spill, but the application of dispersant to oil spills in marine environments remains controversial. Here, we report metagenomic (MG) and metatranscriptomic (MT) data mining from microcosm experiments investigating the oil degrading potential of Canadian west and east coasts to estimate the gene abundance and activity of oil degrading bacteria in the presence of dispersant. We found that the addition of dispersant to crude oil mainly favours the abundance of Thalassolituus in the summer and Oleispira in the winter, two key natural oil degrading bacteria. We found a high abundance of genes related not only to n‐alkane and aromatics degradation but also associated with transporters, two‐component systems, bacterial motility, secretion systems and bacterial chemotaxis.Tribovillard, N., Koched, H., Baudin, F., Adatte, T., Delattre, M., Abraham, R., Ferry, J.-N., 2019. Storm-induced concentration of sulfurized, marine-origin, organic matter as a possible mechanism in the formation of petroleum source-rock. Marine and Petroleum Geology 109, 808-818. shales, though laminated, are not systematically synonymous with quiet conditions of deposition. A number of papers report about black shales yielding sedimentary structures echoing relatively high hydrodynamic conditions. Here we examine two sedimentary sequences pertaining to the Late Jurassic Argiles de Ch?tillon Formation of the Boulonnais area (Northernmost France), each of them including a meter-thick black-shale horizon. The two laminated black shales contain sulfurized (i.e., organic S-rich) organic matter, reaching a maximum of 9%. However, some differences set the two black shales apart. The lower one was deposited under calm, suboxic to anoxic, bottom-water conditions (the ? classic???way); the upper black shale was deposited under oxic, agitated bottom-water conditions, not compatible with stable sulfidic conditions required for organic-matter sulfurization. The upper black shale experienced hydrodynamically-induced concentration of sulfurized, recalcitrant organic matter of marine origin. The sulfurized organic matter could be preserved and quantitatively accumulated owing to its non-putrescible nature, leading to the formation of a potential hydrocarbon source rock. The association of pyrite inclusions with sulfurized organic matter probably modified the hydrodynamic behavior of organic particles. The storm-induced remobilization and concentration of sulfurized organic matter implies that the “sulfurization factory” operated in proximal, shallow environments such as estuaries, mud flats or mangrove environments. Such a model is in agreement with findings from modern coastal/shelf environments (notably mangroves) and fully transposable to many other sedimentary situations of any geological time period.Truba?, J., Magna, T., ?ejková, B., Vondrovicová, L., Rapprich, V., 2019. Rapid determination of carbon isotope composition in carbonatites using isotope ratio mass spectrometry – Comparison of dual-inlet, elemental-analyzer and continuous-flow techniques. Rapid Communications in Mass Spectrometry 33, 1355-1362.: Applications where stable C and O isotope compositions are useful require routine instrumental techniques with a fast sample throughput which should also produce accurate and precise results. We present a comparison of three different instrumental isotope ratio mass spectrometry (IRMS) approaches (Dual Inlet ‐ DI; Elemental Analyzer ‐ EA; Continuous Flow ‐ CF) to determine the stable isotope composition of carbon in carbonate matrices, with a focus on evaluating the optimum approach for less complex instrumental techniques.Methods: The DI‐IRMS method is taken as an absolute method for obtaining accurate and precise 13C/12C ratios with internal errors usually < ±0.01‰ (2SD) and long‐term reproducibility better than ±0.03‰ (2SD). The drawbacks of DI‐IRMS are that it requires extensive offline sample preparation, rather large sample sizes (commonly >20?mg) and extended analysis times. Results: EA‐IRMS provides rapidity of analysis, relatively non‐complex technique optimization and large sample throughput sufficient to distinguish natural trends although the larger internal errors and poorer reproducibility must be considered. The major disadvantage of EA‐IRMS lies in a constant offset of the 13C/12C ratios against DI‐IRMS, large internal errors (±0.2‰, 2SD) and the worst reproducibility (±0.3‰, 2SD) of all the explored methods. The results acquired using CF‐IRMS are comparable with those obtained by employing DI‐IRMS with an external reproducibility better than ±0.2‰ (2SD). Compared with EA‐IRMS, however, this technique requires more elaborate sample preparation – more akin to DI‐IRMS. None of these two latter techniques can provide C isotope results for coexisting phases such as calcite, dolomite and ankerite unless they are physically separated and analyzed independently. Conclusions: All methods are appropriate for 13C/12C determinations with CF‐IRMS and EA‐IRMS less applicable to high‐precision measurements but relevant for studies requiring high sample throughput. Periodical analysis of matrix‐matched reference materials during the analytical sequence is warranted for both EA‐IRMS and CF‐IRMS. Tsuchiya, T., Ehara, A., Kasahara, Y., Hamamura, N., Amachi, S., 2019. Expression of genes and proteins involved in arsenic respiration and resistance in dissimilatory arsenate-reducing Geobacter sp. strain OR-1. Applied and Environmental Microbiology 85, e00763-19.: The reduction of arsenate [As(V)] to arsenite [As(III)] by dissimilatory As(V)-reducing bacteria, such as Geobacter spp., may play a significant role in arsenic release from anaerobic sediments into groundwater. The biochemical and molecular mechanisms by which these bacteria cope with this toxic element remain unclear. In this study, the expression of several genes involved in arsenic respiration (arr) and resistance (ars) was determined using Geobacter sp. strain OR-1, the only cultured Geobacter strain capable of As(V) respiration. In addition, proteins expressed differentially under As(V)-respiring conditions were identified by semiquantitative proteomic analysis. Dissimilatory As(V) reductase (Arr) of strain OR-1 was localized predominantly in the periplasmic space, and the transcription of its gene (arrA) was upregulated under As(V)-respiring conditions. The transcription of the detoxifying As(V) reductase gene (arsC) was also upregulated, but its induction required 500 times higher concentration of As(III) (500?μM) than did the arrA gene. Comparative proteomic analysis revealed that in addition to the Arr and Ars proteins, proteins involved in the following processes were upregulated under As(V)-respiring conditions: (i) protein folding and assembly for rescue of proteins with oxidative damage, (ii) DNA replication and repair for restoration of DNA breaks, (iii) anaplerosis and gluconeogenesis for sustainable energy production and biomass formation, and (iv) protein and nucleotide synthesis for the replacement of damaged proteins and nucleotides. These results suggest that strain OR-1 copes with arsenic stress by orchestrating pleiotropic processes that enable this bacterium to resist and actively metabolize arsenic.Importance: Dissimilatory As(V)-reducing bacteria, such as Geobacter spp., play significant roles in arsenic release and contamination in groundwater and threaten the health of people worldwide. However, the biochemical and molecular mechanisms by which these bacteria cope with arsenic toxicity remain unclear. In this study, it was found that both respiratory and detoxifying As(V) reductases of a dissimilatory As(V)-reducing bacterium, Geobacter sp. strain OR-1, were upregulated under As(V)-respiring conditions. In addition, various proteins expressed specifically or more abundantly in strain OR-1 under arsenic stress were identified. Strain OR-1 actively metabolizes arsenic while orchestrating various metabolic processes that repair oxidative damage caused by arsenic. Such information is useful in assessing and identifying possible countermeasures for the prevention of microbial arsenic release in nature.Ulrich, B.A., Mitton, M., Lachenmeyer, E., Hecobian, A., Zimmerle, D., Smits, K.M., 2019. Natural gas emissions from underground pipelines and implications for leak detection. Environmental Science & Technology Letters 6, 401-406. natural gas (NG) leaks pose an urgent safety threat, motivating ongoing efforts to improve leak detection methods. The objectives of this study were to investigate how realistic environmental conditions affect methane concentration distributions near leaking underground NG distribution pipelines and ultimately to inform protocols for leak detection by walking surveys. In the first study to do so to date, subsurface and atmospheric methane concentrations were measured at high spatial resolution at a field-scale testbed configured to allow controlled release of NG from an underground source. Our findings demonstrate the importance of considering the effects of subsurface processes with respect to above-ground methane concentrations measured in walking surveys. While subsurface methane concentrations from a large leak (0.52 kg/h of NG, 0.44 kg/h of methane) exceeded 80 vol % 20 cm below the ground, atmospheric concentrations dropped below 100 ppmv (0.01 vol %) within the first 10 cm above the ground when the average wind speed was >2 m/s, demonstrating substantial atmospheric dilution in a narrow boundary layer above the surface under moderate wind conditions. Our analysis indicates that detectors with minimum detection limits on the order of 10 ppmv may be required to detect large underground leaks under certain environmental conditions. While efforts to assess a broader range of leak rates and environmental conditions are ongoing, the findings of this study provide critical insight to practitioners regarding detector performance and placement requirements for walking surveys.Uribe-Flores, M.M., Cerqueda-García, D., Hernández-Nu?ez, E., Cadena, S., García-Cruz, N.U., Trejo-Hernández, M.R., Aguirre-Macedo, M.L., García-Maldonado, J.Q., 2019. Bacterial succession and co-occurrence patterns of an enriched marine microbial community during light crude oil degradation in a batch reactor. Journal of Applied Microbiology 127, 495-507.: The aim of this study was to investigate the dynamic changes in the bacterial structure and potential interactions of an acclimatized marine microbial community during a light crude oil degradation experiment.Methods and Results: The bacterial community effectively removed 76·49% of total petroleum hydrocarbons after 30 days, as evidenced by GC‐FID and GC‐MS analyses. Short‐chain alkanes and specific aromatic compounds were completely degraded within the first 6 days. High‐throughput sequencing of 16S rRNA gene indicated that the starting bacterial community was mainly composed by Marinobacter and more than 30 non‐dominant genera. Bacterial succession was dependent on the hydrocarbon uptake with Alcanivorax becoming dominant during the highest degradation period. Sparse correlations for compositional data algorithm revealed one operational taxonomic unit (OTU) of Muricauda and an assembly of six OTUs of Alcanivorax dieselolei and Alcanivorax hongdengensis as critical keystone components for the consortium network maintenance and stability. Conclusions: This work exhibits a stabilized marine bacterial consortium with the capability to efficiently degrade light crude oil in 6 days, under laboratory conditions. Successional and interaction patterns were observed in response to hydrocarbon consumption, highlighting potential interactions between Alcanivorax and keystone non‐dominant OTUs over time. Significance and Impact of the Study: Our results contribute to the understanding of interactions and potential roles of specific members of hydrocarbonoclastic marine bacterial communities, which will be useful for further bioaugmentation studies concerning the associations between indigenous and introduced micro‐organisms.Ursini, O., Angelini, G., Cataldo, F., Iglesias-Groth, S., 2019. Fullerene radiolysis in astrophysical ice analogs: A mass spectrometric study of the products. Astrobiology 19, 903-914. γ-radiolysis of fullerenes (C60 and C70) was performed to investigate the role of fullerenes as a carbon source in building organic molecules in astrophysical ice analog media. Mass spectrometric analyses and the sequential collision-induced dissociation processes enabled us to determine the plausible chemical structure of new products originated during γ-irradiation of fullerenes. The radiolytic products are grouped into six principal compound families. We assessed the relative yield, as percentage, for each new radiolytic compound, and designed the reaction schemes that lead to γ-irradiation products. The reactions start with the formation of primary radicals due to the radiolysis of solvents that react with the fullerenes' structures, forming fullerene radical adducts. The fate of these fullerene radical adducts depends on two factors: (i) the nature of radicals formed by irradiation of solvents and consequently by their ability to give secondary reactions, (ii) whether the onset of thermalization energy processes occurs or does not occur. Here, we present the results regarding the fragmentation processes that lead to functionalized carbonaceous chains characterized by lower molecular weight. We identify the chemical nature of functionalized chain products, propose the reaction schemes, and quantify their relative yields.Valiya Parambathu, A., Wang, L., Asthagiri, D., Chapman, W.G., 2019. Apolar behavior of hydrated calcite (101?4) surface assists in naphthenic acid adsorption. Energy & Fuels 33, 6119-6125. molecules bind strongly to the polar calcite surface and form a surface-adsorbed layer that has properties akin to an apolar surface. This has important implications for understanding the thermodynamic driving forces underlying the adsorption of acid groups from crude oil, in particular, naphthenic acid, onto calcite. Free energy calculations show that naphthenic acid binds favorably to the water monolayer adsorbed on the calcite surface. However, to bond directly to calcite, a free energy barrier has to be overcome to expel the intervening layer of water. Further, naphthenic acids with longer alkyl chains bind with lower free energy to the calcite surface than those with shorter alkyl chains, and, for the same chain length, branching enhances adsorption. To better understand this behavior, for a specified alkyl chain length, we study adsorption at different temperatures. Consistent with experiments, we find that adsorption is enhanced at higher temperatures. Examination of the enthalpic and entropic contributions to adsorption shows that the adsorption of naphthenic acid is entropically favored.Van Dover, C.L., 2019. Inactive sulfide ecosystems in the deep sea: A review. Frontiers in Marine Science 6, 461. doi: 10.3389/fmars.2019.00461. seafloor massive sulfides that are no longer hydrothermally active are a target for an emergent deep-sea mining industry, but the paucity of ecological studies and environmental baselines for inactive sulfide ecosystems makes environmental management of mining challenging. The current state of knowledge regarding the ecology (microbiology and macrobiology) of inactive sulfides is reviewed here and attention is given to environmental management considerations where lack of knowledge impedes informed policy recommendations and decisions.Verdugo, M.P., Mullin, V.E., Scheu, A., Mattiangeli, V., Daly, K.G., Maisano Delser, P., Hare, A.J., Burger, J., Collins, M.J., Kehati, R., Hesse, P., Fulton, D., Sauer, E.W., Mohaseb, F.A., Davoudi, H., Khazaeli, R., Lhuillier, J., Rapin, C., Ebrahimi, S., Khasanov, M., Vahidi, S.M.F., MacHugh, D.E., Ertu?rul, O., Koukouli-Chrysanthaki, C., Sampson, A., Kazantzis, G., Kontopoulos, I., Bulatovic, J., Stojanovi?, I., Mikdad, A., Benecke, N., Linst?dter, J., Sablin, M., Bendrey, R., Gourichon, L., Arbuckle, B.S., Mashkour, M., Orton, D., Horwitz, L.K., Teasdale, M.D., Bradley, D.G., 2019. Ancient cattle genomics, origins, and rapid turnover in the Fertile Crescent. Science 365, 173-176.: Genome-wide analysis of 67 ancient Near Eastern cattle, Bos taurus, remains reveals regional variation that has since been obscured by admixture in modern populations. Comparisons of genomes of early domestic cattle to their aurochs progenitors identify diverse origins with separate introgressions of wild stock. A later region-wide Bronze Age shift indicates rapid and widespread introgression of zebu, Bos indicus, from the Indus Valley. This process was likely stimulated at the onset of the current geological age, ~4.2 thousand years ago, by a widespread multicentury drought. In contrast to genome-wide admixture, mitochondrial DNA stasis supports that this introgression was male-driven, suggesting that selection of arid-adapted zebu bulls enhanced herd survival. This human-mediated migration of zebu-derived genetics has continued through millennia, altering tropical herding on each continent.Editor's summary: How cow genomes have moo-ved. Cattle were domesticated ～10,000 years ago, but analysis of modern breeds has not elucidated their origins. Verdugo et al. performed genome-wide analysis of 67 ancient Near Eastern Bos taurus DNA samples. Several populations of ancient aurochs were progenitors of domestic cows. These genetic lineages mixed ～4000 years ago in a region around the Indus Valley. Interestingly, mitochondrial analysis indicated that genetic material likely derived from arid-adapted Bos indicus (zebu) bulls was introduced by introgression.Vicente, A., Csiki-Sava, Z., Martín-Closas, C., 2019. European charophyte evolution across the Cretaceous–Paleogene boundary. Palaeogeography, Palaeoclimatology, Palaeoecology 533, 109244. Cretaceous–Paleogene (K/Pg) boundary has traditionally been considered a key moment in charophyte evolution, marked by the extinction of two important Mesozoic families, the Porocharaceae and the Clavatoraceae, and a major turnover within the Characeae. However, new data presented here suggest that one species of the European Porocharaceae (based on gyrogonites) and one species of the Clavatoraceae (based on thalli), persisted into the basal Danian. In addition, a taxonomic revision of the Characeae, coupled with an updated biostratigraphy, shows that this family underwent a step-wise extinction during the latest Cretaceous with only a small number of species becoming extinct at the K/Pg boundary. As a result, changes in charophyte floras around the K/Pg boundary in Europe cannot be considered to represent a major turnover in charophyte evolution. Its effects were more comparable to a normal stage boundary event rather than to a major erathem boundary one. Similar disappearance patterns at the K/Pg boundary have also been recorded in other taxa, including fish and amphibians, showing that aquatic freshwater biotas may somehow be resilient to catastrophic events such as those that occurred during the K/Pg crisis.Vick, S.H.W., Gong, S., Sestak, S., Vergara, T.J., Pinetown, K.L., Li, Z., Greenfield, P., Tetu, S.G., Midgley, D.J., Paulsen, I.T., 2019. Who eats what? Unravelling microbial conversion of coal to methane. FEMS Microbiology Ecology 95, fiz093. communities in subsurface coal seams are responsible for the conversion of coal organic matter to methane. This process has important implications for both energy production and our understanding of global carbon cycling. Despite the environmental and economic importance of this process, little is known about which components of the heterogeneous coal organic matter are biodegradable under methanogenic conditions. Similarly, little is known about which taxa in coal seams carry out the initial stages of coal organics degradation. To identify the biodegradable components of coal and the microorganisms responsible for their breakdown, a subbituminous coal was fractionated into a number of chemical compound classes which were used as the sole carbon source for growth by a coal seam microbial community. This study identifies 65 microbial taxa able to proliferate on specific coal fractions and demonstrates a surprising level of substrate specificity among members of this coal-degrading microbial consortia. Additionally, coal kerogen, the solvent-insoluble organic component of coal often considered recalcitrant to microbial degradation, appeared to be readily converted to methane by microbial degradation. These findings challenge our understanding of coal organic matter catabolism and provide insights into the catabolic roles of individual coal seam bacteria.Vickers, M.L., Bajnai, D., Price, G.D., Linckens, J., Fiebig, J., 2019. Southern high-latitude warmth during the Jurassic–Cretaceous: New evidence from clumped isotope thermometry. Geology 47, 724-728. order to understand the climate dynamics of the Mesozoic greenhouse world, it is vital to determine paleotemperatures from higher latitudes. For the Jurassic and Cretaceous climate, there are significant discrepancies between different proxies and between proxy data and climate models. We determined paleotemperatures from Late Jurassic and Early Cretaceous belemnites using the carbonate clumped isotope paleothermometer and compared these values to temperatures derived from TEX86 and other proxies. From our analyses, we infer an average temperature of ～25 °C for the upper part of the water column of the southern Atlantic Ocean. Our data imply that for mid- to high latitudes, climate models underestimate marine temperatures by >5 °C and, therefore, the amount of warming that would accompany an increase in atmospheric CO2 of more than 4× pre-industrial levels, as is projected for the near future.Vidal, C., 2019. Pulsar positioning system: a quest for evidence of extraterrestrial engineering. International Journal of Astrobiology 18, 213-234. have at least two impressive applications. First, they can be used as highly accurate clocks, comparable in stability to atomic clocks; secondly, a small subset of pulsars, millisecond X-ray pulsars, provide all the necessary ingredients for a passive galactic positioning system. This is known in astronautics as X-ray pulsar-based navigation (XNAV). XNAV is comparable to GPS, except that it operates on a galactic scale. I propose a SETI-XNAV research program to test the hypothesis that this pulsar positioning system might be an instance of galactic-scale engineering by extraterrestrial beings. The paper starts by exposing the basics of pulsar navigation, continues with a critique of the rejection of the extraterrestrial hypothesis when pulsars were first discovered. The core section of the paper proposes lines of inquiry for SETI-XNAV, related to the pulsar distribution and power in the galaxy; their population; their evolution; possible pulse synchronizations; pulsar usability when navigating near the speed of light; decoding galactic coordinates; directed panspermia; and information content in pulses. Even if pulsars are natural, they are likely to be used as standards by ETIs in the galaxy. I discuss possible objections and potential benefits for humanity, whether the research program succeeds or not.Vinci, G., Mazzei, P., Bridoux, M., Drosos, M., Piccolo, A., 2019. Molecular characterization of organic matter in two calcareous soils: the effects of an acid decarbonation treatment. Analytical and Bioanalytical Chemistry 411, 5243-5253. molecular composition of soil organic matter (SOM) of two calcareous soils highly rich in carbonates was assessed before and after decarbonation by acid washing with HCl through 13C-CPMAS-NMR spectroscopy and off-line thermochemolysis coupled with gas chromatography and mass spectrometry (THM-GC-MS). The acidic treatment promoted a considerable concentration of organic matter in both soils, thus improving the identification of molecules otherwise not easily detectable. Decarbonation induced only a slight loss of soil organic carbon (SOC), corresponding to 1.4 and 2.7% for A and B soils respectively. The acidic treatment also led to an increase in the organic carbon/total nitrogen (OC/N) ratio in soil A, while an opposite variation was found for the second soil. Moreover, variations in the concentration and molecular distribution of specific compound classes present in SOM were caused by the acid washing of soils. As confirmed by both 13C-CPMAS-NMR and thermochemolysis results, the molecules most susceptible to the acid treatment were the carbohydrates, lignin monomers (G14 and G15), fatty acids (C18 saturated and unsaturated), fatty acids of microbial origin (C15, C17, and C19), hydroxy acids (C16, C18), and dioic acids (C18) which represent the components weakly bound to the organic matrix. Our findings not only showed the efficacy of the decarbonation treatment of calcareous soils with 3 N HCl, but also indicated how the acidic washing can improve the differentiation of soils on the basis of SOM molecular characteristics.Visser, R., John, T., Patzek, M., Bischoff, A., Whitehouse, M.J., 2019. Sulfur isotope study of sulfides in CI, CM, C2ung chondrites and volatile-rich clasts – Evidence for different generations and reservoirs of sulfide formation. Geochimica et Cosmochimica Acta 261, 210-223. aspects of the solar system’s formation process and the origin of planetary bodies can be achieved by examining primitive solar system materials, as these materials reflect the early solar system composition and may represent the building blocks of planetary bodies. Along these lines, knowing the original composition of carbonaceous chondrite meteorites is a valuable asset for determining the conditions in the parent bodies where they formed. Therefore, to determine the key characteristics of the parent bodies from which the carbonaceous chondrites and primitive materials are derived, we examined chemical and sulfur isotope compositions of sulfides in CM, CI and C2ung carbonaceous chondrites as well as from CM- and CI-like volatile-rich clasts; such an investigation allows us to explore the origin of these sulfides and to determine the primordial S composition of their parent body source region. In this study, sulfides from 7 CM, CI, and C2ung carbonaceous chondrites and 16 chondritic and achondritic breccias containing volatile-rich clasts were analyzed by electron microprobe and SIMS. Different sulfides were found, which shows evidence of different formation origins. Based on compositions and exsolution textures, we suggest that one fraction of the sulfides in both clasts and chondrites formed at high temperatures prior to incorporation into the parent body. The other sulfides most likely have a secondary origin and precipitated during fluid–rock interaction. Furthermore, differences in the S isotopic signature of the sulfides in chondrites correlate with the degree of aqueous alteration of the carbonaceous host rocks (CM or CI). Studying the sulfides of the volatile-rich clasts in brecciated chondrites and achondrites, a similar fractionation cannot be seen. Even though the mineralogy of CI chondrites and CI-like clasts is similar, the sulfides in CI chondrites appear to be enriched in heavy isotopes compared to those in the clasts (δ34S?+?1‰ (CI) vs ?2‰ (CI-like clast). This could have been caused by different alteration conditions, or it represents a different sampling reservoir. In this study a large S isotopic fractionation between pentlandite and pyrrhotite was found in large primarily formed sulfides showing exsolution textures, indicating that pentlandite prefers to incorporate light S isotopes. Considering the S isotope composition of the exsolved phase which can be found in CM- and CI-like clasts, the pristine δ34S value of the original monosulfide solid solution (mss) is estimated to be ～?2‰. This value possibly resembles the sampling reservoir from which the sulfides formed, indicating that both CM- and CI-like clasts derived from a similar reservoir, and this reservoir is different from the formation reservoir of the CI chondrites.Wade, L., 2019. Was our species in Europe 210,000 years ago? Science 365, 111. the late 1970s, anthropologists exploring a cave on the rugged coast of southern Greece found two mysterious hominin skull fossils. Time had left them fragmented and distorted, and the jumbled stratigraphy of the cave made them hard to date. For decades, the fossils sat on a shelf, their identity unknown. Now, a state-of-the-art analysis of their shape together with new dates suggest one skull might represent our own species, living in Greece more than 200,000 years ago. The findings, reported in Nature this week, would make this the oldest known Homo sapiens fossil found in Europe, by at least 150,000 years.If so, H. sapiens's first forays out of its African cradle likely happened earlier and extended much farther than most paleoanthropologists thought, into territory dominated by Neanderthals, our extinct cousins. “And then [H. sapiens] disappeared” from Europe, says Eric Delson, a paleoanthropologist at the City University of New York in New York City, until a later wave successfully spread across the continent about 50,000 years ago. But because the evidence is no more than a piece from the back of the skull, some researchers aren't sure the fossil can be definitively identified as H. sapiens. And others question the old date.Katerina Harvati, a paleoanthropologist at the University of Tübingen in Germany, has long suspected that southeast Europe was a hot spot for ancient humans. Not only is the region “at the crossroads of three continents”—Africa, Asia, and Europe—but it enjoyed a relatively mild climate when other parts of Europe were covered by glaciers, she says. So she was thrilled to receive permission to study the fossils, which are named for the cave. The first individual, Apidima 1, is represented by the skull piece. The second, Apidima 2, is more complete and includes the face.The Apidima 1 skull fragment was more complete on one side than the other, and Apidima 2's skull and face were distorted. So Harvati began by figuring out what they originally looked like. She and her team scanned both fossils with x-rays and created 3D reconstructions. They digitally broke Apidima 2 into 66 bone fragments and painstakingly reassembled them into what was likely their original shape. The result showed the face of a typical Neanderthal, jutting from the skull and complete with protruding brow ridges. The ratio of uranium to its decay products in the bones revealed an age of about 170,000 years old.For Apidima 1, Harvati and her team created a mirror image of the fossil and stitched the two together to see the full shape of the back of the skull. It was short and round, like the skulls of H. sapiens, and lacked a ridge and furrow that Neanderthal skulls typically have at the back. “You couldn't bend [the Apidima 1 reconstruction] into a classic Neanderthal cranium,” agrees Christoph Zollikofer, a paleoanthropologist at the University of Zurich in Switzerland who wasn't involved in the research. Harvati and her team concluded that the skull most likely belonged to H. sapiens.In the late 1970s, anthropologists exploring a cave on the rugged coast of southern Greece found two mysterious hominin skull fossils. Time had left them fragmented and distorted, and the jumbled stratigraphy of the cave made them hard to date. For decades, the fossils sat on a shelf, their identity unknown. Now, a state-of-the-art analysis of their shape together with new dates suggest one skull might represent our own species, living in Greece more than 200,000 years ago. The findings, reported in Nature this week, would make this the oldest known Homo sapiens fossil found in Europe, by at least 150,000 years.If so, H. sapiens's first forays out of its African cradle likely happened earlier and extended much farther than most paleoanthropologists thought, into territory dominated by Neanderthals, our extinct cousins. “And then [H. sapiens] disappeared” from Europe, says Eric Delson, a paleoanthropologist at the City University of New York in New York City, until a later wave successfully spread across the continent about 50,000 years ago. But because the evidence is no more than a piece from the back of the skull, some researchers aren't sure the fossil can be definitively identified as H. sapiens. And others question the old date.Katerina Harvati, a paleoanthropologist at the University of Tübingen in Germany, has long suspected that southeast Europe was a hot spot for ancient humans. Not only is the region “at the crossroads of three continents”—Africa, Asia, and Europe—but it enjoyed a relatively mild climate when other parts of Europe were covered by glaciers, she says. So she was thrilled to receive permission to study the fossils, which are named for the cave. The first individual, Apidima 1, is represented by the skull piece. The second, Apidima 2, is more complete and includes the face.The Apidima 1 skull fragment was more complete on one side than the other, and Apidima 2's skull and face were distorted. So Harvati began by figuring out what they originally looked like. She and her team scanned both fossils with x-rays and created 3D reconstructions. They digitally broke Apidima 2 into 66 bone fragments and painstakingly reassembled them into what was likely their original shape. The result showed the face of a typical Neanderthal, jutting from the skull and complete with protruding brow ridges. The ratio of uranium to its decay products in the bones revealed an age of about 170,000 years old.For Apidima 1, Harvati and her team created a mirror image of the fossil and stitched the two together to see the full shape of the back of the skull. It was short and round, like the skulls of H. sapiens, and lacked a ridge and furrow that Neanderthal skulls typically have at the back. “You couldn't bend [the Apidima 1 reconstruction] into a classic Neanderthal cranium,” agrees Christoph Zollikofer, a paleoanthropologist at the University of Zurich in Switzerland who wasn't involved in the research. Harvati and her team concluded that the skull most likely belonged to H. sapiens.Wagner, N., Ashkenasy, G., 2019. Rhythm before life. Nature Chemistry 11, 681-683. chemical functionality necessary for the origin of life may have emerged from simple reactions assembled into complex networks. Now, it has been shown that prebiotically relevant heterogeneous reaction networks can generate robust oscillations within complex mixtures comprised of precursors that do not oscillate on their own.Walhout, E.Q., Dorn, S.E., Martens, J., Berden, G., Oomens, J., Cheong, P.H.Y., Kroll, J.H., O’Brien, R.E., 2019. Infrared ion spectroscopy of environmental organic mixtures: Probing the composition of α-pinene secondary organic aerosol. Environmental Science & Technology 53, 7604-7612. the chemical composition of organic aerosols can elucidate aging mechanisms as well as the chemical and physical properties of the aerosol. However, the high chemical complexity and often low atmospheric abundance present a difficult analytical challenge. Milligrams or more of material may be needed for speciated spectroscopic analysis. In contrast, mass spectrometry provides a very sensitive platform but limited structural information. Here, we combine the strengths of mass spectrometry and infrared (IR) action spectroscopy to generate characteristic IR spectra of individual, mass-isolated ion populations. Soft ionization combined with in situ infrared ion spectroscopy, using the tunable free-electron laser FELIX, provides detailed information on molecular structures and functional groups. We apply this technique, along with quantum mechanical modeling, to characterize organic molecules in secondary organic aerosol (SOA) formed from the ozonolysis of α-pinene. Spectral overlap with a standard is used to identify cis-pinonic acid. We also demonstrate the characterization of isomers for multiple SOA products using both quantum mechanical computations and analyses of fragment ion spectra. These results demonstrate the detailed structural information on isolated ions obtained by combining mass spectrometry with fingerprint IR spectroscopy.Wallace, R., 2019. The aerobic transition as an economic ratchet. International Journal of Astrobiology 18, 199-203. equilibrium, in the sense of Eldredge and Gould in 1972, and path dependence (Gould in 2002), dominate evolutionary processes, many of whose dynamics can be expressed in terms of interacting information sources (Wallace in 2010). Argument based on Feynman's (in 2000) characterization of information as a form of free energy leads to a close, if inverse, analogy between evolutionary transitions and economic ratchets. Driven by such a ‘self-referential’ mechanism, increases in available metabolic free energy – via the aerobic transition – led to the eukaryotic transition and to life as we know it. Formal analysis focuses on groupoid symmetries associated with the cognitive processes of gene expression, an extension of the symmetry breaking/making perspectives of physical science into biological phenomena. This suggests that understanding modalities of cognitive gene expression, as opposed to focus on genes themselves, provides the deepest insight into evolutionary phenomena, a perspective at some variance with current simplistic gene-centred views that constrain evolutionary theory.Wang, C., Zhang, B., Hu, Q., Shu, Z., Sun, M., Bao, H., 2019. Laminae characteristics and influence on shale gas reservoir quality of lower Silurian Longmaxi Formation in the Jiaoshiba area of the Sichuan Basin, China. Marine and Petroleum Geology 109, 839-851. developed in shale strata, laminae are the most typical shale sedimentary structure. To investigate their influence on shale gas reservoir quality, we conducted complementary studies by integrating microscopic observations, geochemical analyses, field-emission scanning electron microscopy (FE-SEM) imaging, and mercury intrusion capillary pressure (MICP) techniques. The microscopic observation of thin sections enabled us to detect the laminae characteristics, including the density and maximum thickness of individual lamina, and three types and stages of lamina development were identified. The total organic carbon (TOC) content, mineral composition, natural fracture, pore type, pore size distribution, porosity, permeability, and tortuosity were investigated in these different laminae types using FE-SEM, MICP and geochemical analysis. Combining the laminae characteristics and pore structure, we concluded that the organic pores and total pore area are mainly affected by the TOC content, whereas the development of the laminae controls the inorganic macropore scale and affects the pore size distribution. In addition, we found that the excessive development of shale laminae is not conducive to organic matter accumulation because of the change in redox condition, and because it has an adverse impact on the formation of complex artificial fractures during hydraulic fracturing.Wang, D., Vannier, J., Schumann, I., Wang, X., Yang, X.-G., Komiya, T., Uesugi, K., Sun, J., Han, J., 2019. Origin of ecdysis: fossil evidence from 535-million-year-old scalidophoran worms. Proceedings of the Royal Society B: Biological Sciences 286, 20190791. millions of extant species, ecdysozoans (Scalidophora, Nematoida and Panarthropoda) constitute a major portion of present-day biodiversity. All ecdysozoans secrete an exoskeletal cuticle which must be moulted periodically and replaced by a larger one. Although moulting (ecdysis) has been recognized in early Palaeozoic panarthropods such as trilobites and basal groups such as anomalocaridids and lobopodians, the fossil record lacks clear evidence of ecdysis in early scalidophorans, largely because of difficulties in recognizing true exuviae. Here, we describe two types of exuviae in microscopic scalidophoran worms from the lowermost Cambrian Kuanchuanpu Formation (ca 535 Ma) of China and reconstruct their moulting process. These basal scalidophorans moulted in a manner similar to that of extant priapulid worms, extricating themselves smoothly from their old tubular cuticle or turning their exuviae inside out like the finger of a glove. This is the oldest record of moulting in ecdysozoans. We also discuss the origin of ecdysis in the light of recent molecular analyses and the significance of moulting in the early evolution of animals.Wang, E., Wang, Z., Pang, X., Zhang, Z., Wang, Z., Wu, Z., Liang, Y., Feng, Y., Zhang, Z., 2019. Key factors controlling hydrocarbon enrichment in a deep petroleum system in a terrestrial rift basin—A case study of the uppermost member of the upper Paleogene Shahejie Formation, Nanpu Sag, Bohai Bay Basin, NE China. Marine and Petroleum Geology 107, 572-590., petrographical, geochemical analyses, and fluid inclusions petrography and microthermometry were combined to investigate the basic properties of the source rock (organic matter content, kerogen type, and thermal maturity) and sandstone reservoirs (composition, pore systems, porosity, and permeability), the hydrocarbon origin, and the formation mechanisms of the deep (>3.5?km) petroleum system in the Upper Paleogene Es1 (the uppermost member of the Shahejie Formation) in the No. 3 Structural Belt in the Nanpu Sag, Bohai Bay Basin. The results indicate that the Es1 source rock is primarily composed of dark gray mudstone and presents a set of high-quality source rocks (>500?m, average total organic carbon (TOC) 1.38%, in a mature stage (maximum pyrolysis yield of 430?°C–460?°C)). The Es1 sandstone is composed of lithic arkose formed in a braided river delta and has low porosity (average 13.4%) but moderate-high permeability (average 184.9 mD). The hydrocarbons originated from the Es1 source rocks in the Caofeidian subsag during two charging periods: 10?Ma and 3?Ma. The key factors controlling the formation of the deep petroleum system are as follows: (a) High-quality hydrocarbon supply, (b) Medium-high permeability reservoirs, (c) A favorable configuration of the source rock and reservoirs (self-generated and self-accumulated), and (d) Late hydrocarbon charging; the second factor is the most important. The medium-high permeability reservoirs are attributed to a high-energy depositional environment (distributary channels of braid delta front), a high content of rigid detrital grains (mainly quartz and metamorphic rock fragments) provided by the Archean granite provenance, and the secondary pores formed by feldspar dissolution. This study provides a new example for revealing the formation mechanisms of deep (>3.5?km) petroleum systems in the terrestrial rift basin across the Bohai Bay Basin.Wang, F., Cvirkaite-Krupovic, V., Kreutzberger, M.A.B., Su, Z., de Oliveira, G.A.P., Osinski, T., Sherman, N., DiMaio, F., Wall, J.S., Prangishvili, D., Krupovic, M., Egelman, E.H., 2019. An extensively glycosylated archaeal pilus survives extreme conditions. Nature Microbiology 4, 1401-1410. on the surface of Sulfolobus islandicus are used for many functions, and serve as receptors for certain archaeal viruses. The cells grow optimally at pH?3 and ~80?°C, exposing these extracellular appendages to a very harsh environment. The pili, when removed from cells, resist digestion by trypsin or pepsin, and survive boiling in sodium dodecyl sulfate or 5?M guanidine hydrochloride. We used electron cryo-microscopy to determine the structure of these filaments at 4.1?? resolution. An atomic model was built by combining the electron density map with bioinformatics without previous knowledge of the pilin sequence—an approach that should prove useful for assemblies where all of the components are not known. The atomic structure of the pilus was unusual, with almost one-third of the residues being either threonine or serine, and with many hydrophobic surface residues. While the map showed extra density consistent with glycosylation for only three residues, mass measurements suggested extensive glycosylation. We propose that this extensive glycosylation renders these filaments soluble and provides the remarkable structural stability. We also show that the overall fold of the archaeal pilin is remarkably similar to that of archaeal flagellin, establishing common evolutionary origins.Wang, F., Guo, S., 2019. Shale gas content evolution in the Ordos Basin. International Journal of Coal Geology 211, 103231. content is a crucial parameter for shale reservoir evaluation and shale gas accumulation. Taking Shanxi and Taiyuan Formation shale samples from the Ordos Basin of China as an example, this research used thermal simulation, Rock-Eval pyrolysis, total organic carbon content (TOC) measurement, vitrinite reflectance (Ro) measurement, X-ray diffraction analysis, and methane isothermal adsorption based on formation conditions to study the evolution of shale gas content. A thermogenic gas content model was established through thermal simulation, Rock-Eval pyrolysis, and Ro measurement, while the influential factors of adsorbed gas content were analysed and a model was established through TOC and Ro measurements, X-ray diffraction analysis, methane isothermal adsorption, and reservoir conditions. Then, the research characterized the evolution of thermogenic gas, gas-in-place (GIP), adsorbed gas, and free gas through geologic time using a combination of thermogenic gas content, hydrocarbon expulsion and adsorbed gas content models.Wang, H., Yang, J.-H., Kr?ner, A., Zhu, Y.-S., Li, R., 2019. Non-subduction origin for 3.2?Ga high-pressure metamorphic rocks in the Barberton granitoid-greenstone terrane, South Africa. Terra Nova 31, 373-380. occurrence of high-pressure (HP) garnet-bearing metamorphic rocks in the southern Barberton granitoid?greenstone terrane (BGGT), South Africa, has been proposed as a key indicator of the onset of modern plate tectonics at ca. 3.2?Ga. Here, we report new zircon/titanite U?Pb ages of garnet-bearing HP metamorphic rocks and associated granitoids in the BGGT that argue against such an interpretation. The results show that HP metamorphism occurred synchronously with granitoid magmatism in the Stolzburg domain, the supposed subducted plate, during two episodes at 3.4 and 3.2?Ga, and that these two episodes of magmatism occurred on both sides of the assumed suture zone, a feature that cannot easily be explained by the subduction model. In contrast, the coupled magmatism and metamorphism probably resulted from partial convective overturn (PCO), another viable mechanism for production and differentiation of continental crust during early Archean.Wang, K., Wu, X., 2019. Downhole thermoelectric generation in unconventional horizontal wells. Fuel 254, 115530. water production from hydraulically fractured unconventional reservoirs is historically considered as burdensome liability in terms of costly treatment and disposal. However, this paper demonstrated produced water as a valuable asset, which is capable of producing geothermal energy, and it can actually help offset the operation costs for unconventional oil and gas producers. Harnessing geothermal energy of produced water for power generation from unconventional horizontal wells features significant advantages over traditional geothermal wells, especially in reducing capital expenditure and operational risks. This paper proposed a novel design of downhole power generation in horizontal wells by integration of thermoelectric technology with hydrocarbon production.In the design, we retrofit the horizontal wellbore to circulate cold water inside the tubing so that a cold temperature interface can be created. The produced fluids flow through the annulus of the tubing and casing to maintain hot temperature on the side of tubing. By attaching thermoelectric generators (TEG) on the outer surface of tubing, this retrofit will make it possible to capture subsurface in-situ geothermal energy of the produced fluid and directly transfer heat to electricity inside the horizontal wellbore. Furthermore, we also built the mathematical model to account for the heat conduction and convention in the wellbore and surrounding formation, which could accurately simulate the temperature distribution and power generation under variable operational conditions. Based on the model, we identified the key parameters with significant impact on power generation and established the well section criteria for best power generation performance. To discover the potential of power generation in horizontal wells, we conducted a case study in Daqing Oilfield in northeast China and compared the power generation performance with vertical well with same TVD and same power generation device installation. The results of case study indicated that horizontal well displayed exceeding power generation performance over vertical wells.In practice, this paper could contribute to enrich geothermal development methods and provide the guidelines for oil and gas producer to evaluate their horizontal assets and identify the opportunity to capitalize on geothermal power generation from horizontal wells.Wang, N., Collins, I.R., Webb, K.J., Wan, Q., Durkan, C., 2019. Probing the interactions of dolomite surfaces with oil at the molecular scale. Energy & Fuels 33, 6161-6169. oil wettability of reservoir rock surfaces is a key issue affecting oil production and enhanced oil recovery. Understanding the factors that determine this wettability and how to change the rock wetting state is necessary to improve oil recovery efficiency. In this study, atomic force microscopy has been used to study the change of wettability of dolomites after exposure to crude oil. Oil aggregates are seen to adhere to particular areas of the surface in a manner dependent upon the surface electrical potential, with a higher affinity toward regions of the surface with negative charge, indicating that asphaltenes possess a native positive charge. The effect of exposure to brine has also been studied, with the key finding being that, via a modification of the surface potential, it leads to significantly less adsorption of the polar components of oil.Wang, R., Hu, Z., Long, S., Liu, G., Zhao, J., Dong, L., Du, W., Wang, P., Yin, S., 2019. Differential characteristics of the Upper Ordovician-Lower Silurian Wufeng-Longmaxi shale reservoir and its implications for exploration and development of shale gas in/around the Sichuan Basin. Acta Geologica Sinica - English Edition 93, 520-535. Upper Ordovician Wufeng‐Lower Silurian Longmaxi shale is widely distributed in the Sichuan Basin and its periphery, which is the key stratum for marine shale gas exploration and development (E&D) in China. Based on sedimentary environment, material basis, storage space, fracability and reservoir evolution data, the reservoir characteristics of the Wufeng‐Longmaxi shale and their significance for shale gas EE&D are systematically compared and analyzed in this paper. The results show that (1) the depocenter of the Wufeng (WF)‐Longmaxi (LM) shale gradually migrates from east to west. The high‐quality shale reservoirs in the eastern Sichuan Basin are mainly siliceous shales, which are primarily distributed in the graptolite shale interval of WF2‐LM5. The high‐quality reservoirs in the southern Sichuan Basin are mainly calcareous‐siliceous and organic‐rich argillaceous shales, which are distributed in the graptolite shale interval of WF2‐LM7. (2) Deep shale gas (the burial depth >3500 m) in the Sichuan Basin has high‐ultrahigh pressure and superior physical properties. The organic‐rich siliceous, calcareous‐siliceous and organic‐rich argillaceous shales have suitable reservoir properties. The marginal area of the Sichuan Basin has a higher degree of pressure relief, which leads to the argillaceous and silty shales evolving into direct cap rocks with poor reservoir/good sealing capacity. (3) Combining shale gas exploration practices and impacts of lithofacies, depth, pressure coefficient and brittle‐ductile transition on the reservoir properties, it is concluded that the favorable depth interval of the Wufeng‐Longmaxi shale gas is 2200～4000 m under current technical conditions. (4) Aiming at the differential reservoir properties of the Wufeng‐Longmaxi shale in the Sichuan Basin and its periphery, several suggestions for future research directions and EE&D of shale gas are formulated.Wang, R., Yin, Y., Zhu, Z.-J., 2019. Advancing untargeted metabolomics using data-independent acquisition mass spectrometry technology. Analytical and Bioanalytical Chemistry 411, 4349-4357. quantitatively measures metabolites in a given biological system and facilitates the understanding of physiological and pathological activities. With the recent advancement of mass spectrometry (MS) technology, liquid chromatography-mass spectrometry (LC-MS) with data-independent acquisition (DIA) has been emerged as a powerful technology for untargeted metabolomics due to its capability to acquire all MS2 spectra and high quantitative accuracy. In this trend article, we first introduced the basic principles of several common DIA techniques including MSE, all ion fragmentation (AIF), SWATH, and MSX. Then, we summarized and compared the data analysis strategies to process DIA-based untargeted metabolomics data, including metabolite identification and quantification. We think the advantages of the DIA technique will enable its broad application in untargeted metabolomics.Wang, W.-L., Lee, C., Primeau, F.W., 2019. A Bayesian statistical approach to inferring particle dynamics from in-situ pump POC and chloropigment data from the Mediterranean Sea. Marine Chemistry 214, 103654. of chloropigments and particulate organic carbon (POC) in large-volume in-situ pump samples from the Mediterranean Sea were used to estimate rate constants of processes that control the fate of particles, and specifically chloropigments, in the water column. Here we introduce a Bayesian statistical inversion method that combines the data with a new box model and has the capacity to infer rate constants for POC respiration/dissolution, chlorophyll and pheopigment degradation, and particle aggregation and disaggregation. We use first-order kinetics to model disaggregation, and use both first-order and second-order kinetics to model aggregation. Using these methods, the estimated small-particle (1–70?μm) POC respiration rate constant was 2.44?1.00+1.69 yr?1 (0.41?yr). The estimated disaggregation and second-order aggregation rate constants were 85.6?36.4+63.4 yr?1 (1.17×10?2 yr) and 2.78?1.17+2.01 μM?1 yr?1, respectively. . Using the optimal rate constants and the corresponding particle concentrations, disaggregation is ~4.2 times faster than the small-size POC dissolution rate, which indicates that disaggregation is a dominant processes at the time of sampling. More importantly, by comparing our results with those of previous studies, we conclude that sampling methods have less influence than tracers themselves on inferring particle dynamic rate constants. We previously introduced a somewhat similar approach to modeling SV sediment trap data, but large volume pumps are a much more common sample collection method in oceanographic surveys than SV sediment traps, and thus our new model should have a wider applicability.Wang, Y., Li, D.-W., Sachs, J.P., Hu, J., Cao, Y., Li, L., Zhang, H., Zhao, M., 2019. Vertical distribution of isoprenoid GDGTs in suspended particles from the East China Sea shelf and implications for sedimentary TEX86H records. Organic Geochemistry 136, 103895. TEX86H (or TEX86) paleothermometer has been widely applied for reconstructing water temperature in marine settings, particularly in marginal seas which often archive paleoclimate records with high temporal resolution. Yet debate remains regarding the water depth at which the TEX86H signal is imparted in these settings. In this study, East China Sea (ECS) surface sediments and suspended particulate matter (SPM) from different water depths (0–60?m) were analyzed for lipid biomarkers to better constrain the depth to which the sedimentary TEX86H signal corresponds. Our data showed divergent vertical distributions between archaeal lipids and phytoplankton lipids. The maximum concentration of core lipid isoprenoid glycerol dialkyl glycerol tetraethers (core iGDGTs) appeared in bottom waters (2–5?m above the sea floor) at all sites, whereas phytoplankton lipids showed highest abundance in surface waters (0?m). Consistent with the maximum core iGDGTs concentration in bottom waters, the best correlation was observed between SPM TEX86H values and 2–4?weeks averaged water temperatures from the bottom waters. Moreover, the SPM core iGDGTs content was higher in bottom waters than in surface sediments, implying that in situ production rather than sediment resuspension leads to the maximum concentration of core iGDGTs in bottom waters. By compiling published surface sediment data from water depths < 100?m we find that the correlation of TEX86H with bottom water temperature (BWT) exceeds that with sea surface temperature (SST). Therefore, it is proposed that sedimentary TEX86H is a BWT proxy in the shallow ECS.Wang, Z., 2019. Earth’s volatile-element jigsaw. Nature Geoscience 12, 500-502.’s formation by the accretion of volatile-rich carbonaceous chondrite-like materials, without a need for exotic building blocks or secondary volatile loss, is supported by recognition of a plateau pattern for highly volatile elements.To understand Earth’s formation and the origins of the ingredients that make it habitable, it is necessary to constrain Earth’s volatile-element composition1. The chemical composition of Earth is determined by the meteoritic materials that made it; so, to form a complete picture of Earth’s volatile elements we need to piece together the jigsaw of those meteoritic building materials. However, the jigsaw is complicated by poorly constrained volatile-element compositions of primitive meteorites and by processes such as volatile loss during planetary growth, and core formation. Writing in Nature Geoscience, Braukmüller et al.2 reveal a characteristic volatile-element depletion pattern in different types of carbonaceous chondrites that suggests carbonaceous chondrite-like building materials were a significant component of Earth’s accretion.The building blocks of Earth are thought to be compositionally similar to the undifferentiated primitive leftovers from the early Solar System, known as chondritic meteorites. In the canonical model it is assumed that the more volatile the element, the more depleted it is (Fig. 1a) in both the carbonaceous chondrite building blocks and bulk Earth, when normalized to the most primitive meteorites, CI chondrites3. However, as early as the 1970s it was proposed that this trend may level off to a plateau with the highly volatile elements all depleted to the same extent, independent of increasing volatility4.Until the work by Braukmüller and colleagues2,5, this uniform depletion pattern for highly volatile elements in carbonaceous chondrites had been largely ignored. The authors carried out high-precision abundance analyses on sulfur, selenium, and tellurium and combined with other volatile elements5, confirmed that in carbonaceous chondrites, these more volatile elements are indeed depleted by a constant factor and fall on a volatile-element plateau (Fig. 1a).Confirmation of this split depletion pattern for volatile elements eliminates some puzzles about the volatile-element compositions of Earth and its building blocks. For example, following the canonical model of increased depletion with increased volatility, highly volatile indium was considered overabundant on Earth6,7 (Fig. 1b). To explain this indium-excess, it has been suggested: that indium became less volatile in different compartments of the solar nebula7; that Earth’s main building materials differed from known chondritic meteorites7; or that high-energy giant impacts had led to secondary volatile loss and reshaped the volatile-element abundance on Earth8. The refined plateau pattern, confirmed by Braukmüller and colleagues2, provides a simple alternative solution: indium is not overabundant and Earth displays the same plateau depletion pattern as its carbonaceous chondrite-like building materials (Fig. 1b).To define the Earth’s volatile-element composition plateau, the assumption is that volatile elements such as zinc and indium were preserved in the bulk silicate Earth and not lost during planetary accretion and the Moon-forming impact or depleted by core formation. Given the gravitational effects on re-condensation of volatile elements from impact-generated disks9, it is likely that they were retained during Moon formation. For planetary accretion and core formation, experiments have shown zinc and indium to be retained in the bulk silicate Earth at very high pressures and temperatures of core formation10.Retention of elements like zinc and indium in the silicate Earth is somewhat surprising as both zinc and indium are generally thought to be siderophile, with an affinity to metal7, and therefore likely to partition into the core. Indeed, any depletion of siderophile volatile elements such as cadmium, relative to the plateau, should be ascribed to partitioning into Earth’s core (Fig. 1b). Experiments have generally shown indium to have a greater affinity for metal than cadmium7 and so a stronger depletion of indium than cadmium in the bulk silicate Earth would be expected. However, this is not the case (Fig. 1b) and this discrepancy may be overcome if Earth’s core formation involved sulfur- and silicon-rich liquid-metal segregation at different accretion stages11. Future core formation scenarios must simultaneously explain all siderophile volatile elements whose relative abundances in the silicate Earth are below the plateau.A striking dilemma in planetary formation is the observation that Earth chemically matches with carbonaceous chondrites but is isotopically most similar to the enstatite chondrites, which formed in a different region of the solar nebula from carbonaceous chondrites12. From this point of view, Earth’s main building materials differ from any chondritic material in our meteorite collection7. Braukmüller and colleagues suggest that either Earth was built mainly of materials from the enstatite chondrite reservoir, but with carbonaceous chondrite-like chemical compositions, or that carbonaceous chondrites contributed significantly to the Earth and its volatile-element budget but were balanced by building materials that are not present in our meteorite collections in order to make Earth’s isotope composition close to that of enstatite chondrites.With the plateau volatile-element depletion pattern for both Earth and carbonaceous chondrites, Braukmüller and colleagues provide a cosmochemical perspective on Earth’s volatile-element composition. A carbonaceous chondrite-like origin for Earth’s volatiles needs further testing, but it can account for certain chemical features, such as the indium abundance, without unknown building blocks or secondary volatile loss.References1. Albarède, F. Nature 461, 1227–1233 (2009).2. Braukmüller, N., Wombacher, F., Funk, C. & Münker, C. Nat. Geosci. (2019).3. Lodders, K. Astrophys. J. 591, 1220–1247 (2003).4. Takahashi, H., Janssens, M.-J., Morgan, J. W. & Anders, E. Geochim. Cosmochim. Acta 42, 97–106 (1978).5. Braukmüller, N., Wombacher, F., Hezel, D. C., Escoube, R. & Münker, C. Geochim. Cosmochim. Acta 239, 17–48 (2018).6. Witt-Eickschen, G., Palme, H., O’Neill, H. S. C. & Allen, C. M. Geochim. Cosmochim. Acta 73, 1755–1778 (2009).7. Wang, Z., Laurenz, V., Petitgirard, S. & Becker, H. Earth Planet. Sci. Lett. 435, 136–146 (2016).8. Norris, C. A. & Wood, B. J. Nature 549, 507–510 (2017).9. Canup, R. M., Visscher, C., Salmon, J. & Fegley, B. Jr Nat. Geosci. 8, 918–921 (2015).10. Mann, U., Frost, D. J. & Rubie, D. C. Geochim. Cosmochim. Acta 73, 7360–7386 (2009).11. Righter, K. et al. Geochim. Cosmochim. Acta 198, 1–16 (2017).12. Dauphas, N. Nature 541, 521–524 (2017).Ward, L.M., Cardona, T., Holland-Moritz, H., 2019. Evolutionary implications of anoxygenic phototrophy in the bacterial phylum Candidatus Eremiobacterota (WPS-2). Frontiers in Microbiology 10, 1658. doi: 10.3389/fmicb.2019.01658. environmental metagenomic sequencing has uncovered substantial previously unrecognized microbial diversity relevant for understanding the ecology and evolution of the biosphere, providing a more nuanced view of the distribution and ecological significance of traits including phototrophy across diverse niches. Recently, the capacity for bacteriochlorophyll-based anoxygenic photosynthesis has been proposed in the uncultured bacterial WPS-2 phylum (recently proposed as Candidatus Eremiobacterota) that are in close association with boreal moss. Here, we use phylogenomic analysis to investigate the diversity and evolution of phototrophic WPS-2. We demonstrate that phototrophic WPS-2 show significant genetic and metabolic divergence from other phototrophic and non-phototrophic lineages. The genomes of these organisms encode a new family of anoxygenic Type II photochemical reaction centers and other phototrophy-related proteins that are both phylogenetically and structurally distinct from those found in previously described phototrophs. We propose the name Candidatus Baltobacterales for the order-level aerobic WPS-2 clade which contains phototrophic lineages, from the Greek for “bog” or “swamp,” in reference to the typical habitat of phototrophic members of this clade.Warke, M.R., Edwards, N.P., Wogelius, R.A., Manning, P.L., Bergmann, U., Egerton, V.M., Kimball, K.C., Garwood, R.J., Beukes, N.J., Schr?der, S., 2019. Decimeter-scale mapping of carbonate-controlled trace element distribution in Neoarchean cuspate stromatolites. Geochimica et Cosmochimica Acta 261, 56-75. stromatolites can provide key insights into the early evolution of life on Earth. Neoarchean fenestrate stromatolites from the ～2520?Ma Upper Nauga Formation (Transvaal Supergroup, South Africa) preserve cuspate morphologies. They possess clearly delineated support and drape structures interpreted as dolomitized microbial mat material. Petrographic observations show that the biogenic structures are composed of planar-s to non-planar ferroan dolomite, encased in ferroan calcite, including herringbone calcite textures. The cuspate stromatolites were analyzed using Synchrotron Rapid Scanning X-Ray Fluorescence (SRS-XRF) and more conventional techniques to determine: (i) whether element distributions could be distinguished in ancient stromatolites at both cm to dm scales, (ii) whether element distributions show variation between biogenic and abiogenic textures, and (iii) the sample’s paragenesis. The distributions of Ca, Fe, Mn, Pb, Cu, As, Br, Al, Si, P, and S directly correspond to dolomitized stromatolitic structures and show trace element distributions are principally controlled by calcite and dolomite occurrence. Dolomite formation was mainly driven by seawater-derived fluids given the high concentrations of Fe and retention of marine shale-normalized rare earth element and yttrium (REYSN) patterns, however the spatial association of dolomite to stromatolite structures may reflect microbially-influenced mineral nucleation. Given the complexity of this sample’s paragenetic evolution, trace metal distributions cannot be conclusively tied to specific metabolic pathways, bioaccumulation or passive binding, however, the results show SRS-XRF can be used for quantifiable, spatial, in-situ investigation of ancient microbialites.Warren, M., 2019. Move over, DNA: ancient proteins are starting to reveal humanity’s history. Nature 570, 433-436. dating back more than one million years have been extracted from some fossils, and could help to answer some difficult questions about archaic humans.Some time in the past 160,000 years or so, the remains of an ancient human ended up in a cave high on the Tibetan Plateau in China. Perhaps the individual died there, or parts were taken there by its kin or an animal scavenger. In just a few years, the flesh disappeared and the bones started to deteriorate. Then millennia dripped by. Glaciers retreated and then returned and retreated again, and all that was left behind was a bit of jawbone with some teeth. The bone gradually became coated in a mineral crust, and the DNA from this ancient ancestor was lost to time and weather. But some signal from the past persisted.Deep in the hominin’s teeth, proteins lingered, degraded but still identifiable. When scientists analysed them earlier this year, they detected collagen, a structural support protein found in bone and other tissues. And in its chemical signature was a single amino-acid variant that isn’t present in the collagen of modern humans or Neanderthals — instead, it flagged the jawbone as belonging to a member of the mysterious hominin group called Denisovans1. The discovery of a Denisovan in China was a major landmark. It was the first individual found outside Denisova Cave in Siberia, where all other remains of its kind had previously been identified. And the site’s location on the Tibetan Plateau — more than 3,000 metres above sea level — suggested that Denisovans had been able to live in very cold, low-oxygen environments.But the finding also marked another milestone: it was the first time that an ancient hominin had been identified using only proteins.It is one of the most striking discoveries yet for the fledgling field of palaeoproteomics, in which scientists analyse ancient proteins to answer questions about the history and evolution of humans and other animals. Proteins, which stick around in fossils for much longer than DNA does, could allow scientists to explore whole new eras of prehistory and use molecular tools to examine bones from a much broader part of the world than is currently possible, according to the field’s proponents.Previously, scientists had recovered proteins from 1.8-million-year-old animal teeth and a 3.8-million-year-old eggshell. Now, they hope that palaeoproteomics could be used to provide insights about other ancient hominin fossils that have lost all traces of DNA — from Homo erectus, which roamed parts of the world from about 1.9 million to 140,000 years ago, to Homo floresiensis, the diminutive ‘hobbit’ species that lived in Indonesia as recently as 60,000 years ago. By looking at variations in these proteins, scientists hope to answer long-standing questions about the evolution of ancient human groups, such as which lineages were direct ancestors of Homo sapiens. “I think that you can basically unlock the whole of the human tree,” says Matthew Collins, a bioarchaeologist at the University of Copenhagen who has been at the forefront of the field since the 1980s, when it consisted of just a handful of researchers.A coming of age. Despite the excitement, some argue that researchers could struggle to paint a definitive picture of human history from the information that researchers can get out of proteins, which is limited compared with that obtainable from DNA. And many worry that palaeoproteomics in general might be susceptible to spurious results, stemming from issues such as contamination. “You see very good research, and then you see people that publish things that are just very strange, because they don’t think critically about the methods,” says Philipp Stockhammer, an archaeologist at the Ludwig Maximilian University of Munich in Germany.Over the past two decades, DNA retrieved from ancient fossils has transformed scientists’ understanding of human evolution. Analysis of the similarities and differences in the DNA of different hominin groups has allowed researchers to map out the tangled family tree in a way that was previously not possible. And genetic material has led to some major finds, such as the discovery of Denisovans in the first place.But glaring gaps remain in that picture. DNA has been sequenced from just three groups of hominin: Neanderthals, Denisovans and Homo sapiens, mostly from specimens that are less than 100,000 years old (a notable exception is a pair of 430,000-year-old early Neanderthals from Spain2). Go a few hundred thousand years further back, and things get much murkier. This was a time period when a lot of exciting things were happening, says Frido Welker, a molecular anthropologist at the University of Copenhagen. It’s when Denisovans and Neanderthals branched off from the lineage that would become modern humans, for example. But it remains a hazy part of human history. Researchers don’t know, for instance, whether the ancient hominin Homo heidelbergensis, which lived around 700,000–200,000 years ago, was an ancestor of both H. sapiens and Neanderthals or part of only the Neanderthal branch, as some have suggested. “A lot of that happens beyond the reach of ancient DNA,” says Welker.Go back one million years or more, and things get even less clear. H. erectus, for example, first emerged in Africa around 1.9 million years ago, but without DNA evidence, it remains uncertain exactly how it is related to later hominins, including H. sapiens.Ancient DNA has also left geographical blind spots. DNA degrades faster in warm environments, so although a 100,000-year-old specimen found in a cold Siberian cave might still harbour genetic material, a fossil that has spent that long in the heat of Africa or southeast Asia generally will not. As a result, little is known about the genetics of even relatively recent hominins from these regions, such as H. floresiensis.Now researchers are hoping that protein analysis might begin to fill in some of those blanks. The idea is not new: as early as the 1950s, researchers had reported finding amino acids in fossils. But for a long time, the technology needed to sequence ancient proteins just didn’t exist. “For most of my career, I honestly, genuinely believed that we would not be able to recover ancient protein sequences,” says Collins.That changed in the 2000s, after researchers realized that mass spectrometry — a technique used to study modern proteins — could also be applied to ancient proteins. Mass spectrometry essentially involves breaking down proteins into their constituent peptides (short chains of amino acids) and analysing their masses to deduce their chemical make-up.Researchers have used this method to sift through hundreds of bone fragments to identify the types of animal they came from. In this specific approach, called zooarchaeology by mass spectrometry or ZooMS, researchers analyse one kind of collagen. The mass of collagen’s components differs in various groups and species, providing a characteristic fingerprint that allows researchers to identify the bone’s source.ZooMS was used in a 2016 paper3 to identify one hominin bone among thousands of fragments from Denisova Cave — a bone that DNA analysis would later show belonged to a hybrid individual, nicknamed Denny, with a Neanderthal mother and a Denisovan father. Even with that result alone, ancient protein analysis had already substantially expanded our view of human evolution, says population geneticist Pontus Skoglund at the Francis Crick Institute in London. Katerina Douka, an archaeologist at the Max Planck Institute for the Science of Human History in Jena, Germany, is now using the technique to search through 40,000 unidentified bone fragments from Asia in the hope of uncovering more ancient hominins.But ZooMS paints a picture only in broad brushstrokes. Once a bone is identified as belonging to a hominin, for example, other techniques are needed to delve deeper. So others have turned to shotgun proteomics, which aims to identify all the protein sequences in a sample — its proteome. The composition of the proteome depends on the kind of tissue being examined, but will often include various forms of collagen. This method spits out thousands of signals, which makes it much more informative than ZooMS, says Douka, but also trickier to interpret. By matching these signals to known sequences in databases, researchers can identify the exact sequences of collagen or other proteins in their sample.Scientists can then compare this newly determined protein sequence to the same protein from other hominin groups, looking for similarities and differences in individual amino acids that will help to place the hominin on the family tree. This is similar to how ancient-DNA researchers look at single-letter variations in genetic sequences.Filling in the gapsAlthough researchers had used protein analysis alongside ancient DNA sequencing before4, the Tibetan Denisovan was the first ancient hominin for which proteins alone were analysed — and others could soon follow (see ‘Getting fossils to speak’). A look at the protein sequences from H. heidelbergensis, for example, could clarify its relationship to H. sapiens and Neanderthals.Debates have swirled for a decade and a half over the nature of H. floresiensis, remains of which were discovered on the Indonesian island of Flores in 2003. Its relationship to other hominins is unclear, with suggestions that it could be a dwarf descendant of H. erectus, or perhaps even that it evolved from the Australopithecus genus that is more distantly related to modern humans. This group lived more than 2 million years ago, and counts the famous Lucy skeleton among its members.Proteomics could put that mystery to bed, says Collins. “I am utterly convinced that we have Homo floresiensis protein around, and it will be sequenceable, and it will tell us where that fits in the family tree,” he says. The same could be true of another small hominin, Homo luzonensis. Its bones and teeth were discovered in a cave on the island of Luzon in the Philippines several years ago, and reported on earlier this year5. Similarly to H. floresiensis, these samples have yielded no DNA. Armand Salvador Mijares, an archaeologist at the University of the Philippines in Quezon City, says that he is planning to send Welker an animal tooth from the cave where H. luzonensis was found, to test the viability of analysing proteins in ancient tropical materials.As researchers prepare to do more proteomic analysis on ancient hominins, work on other animals is already revealing much about their evolutionary relationships in the deep past.In a recent analysis, for example, Welker and his colleagues used proteomics to work out where the extinct rhinoceros Stephanorhinus fits on the rhino family tree. As reported in a preprint that has not yet been peer reviewed6, the team was able to extract proteins in remains from Dmanisi, Georgia, that were nearly 1.8 million years old. The pattern of amino-acid substitutions suggests that the animal was closely related to the extinct woolly rhinoceros (Coelodonta antiquitatis).Whereas the proteins of the Tibetan Denisovan came from dentine, the bony tissue inside teeth, these Stephanorhinus proteins were locked away in the enamel that covers the tooth. This could be particularly useful for finding very old proteins, suggests Enrico Cappellini, a palaeoproteomics specialist at the University of Copenhagen and a co-author on the Stephanorhinus work. Enamel is the hardest material in the vertebrate body and acts as what Cappellini calls a closed system, preventing amino acids from leaching out. The 1.8-million-year-old date “doesn’t represent a limit”, he says.In fact, others have gone further back. Researchers have reported extracting collagen sequences from a 3.4-million-year-old camel found in the Arctic7. And in a 2016 paper, Beatrice Demarchi, a biomolecular archaeologist at the University of Turin, Italy, and her colleagues extracted and sequenced proteins from a 3.8-million-year-old ostrich eggshell8. This shell wasn’t preserved in a cold polar region: it came from a site in Tanzania, where the average annual air temperature is around 18?°C, says Demarchi. “You would not expect stuff to survive in such a hot environment,” she says. Hominin proteins might be recoverable from the same places, she adds: “We’ve got to try, don’t we?”Teething painsThere are still hurdles to overcome before ancient proteins can bring the branches of the human evolutionary tree into focus. So far, researchers have been able to deduce the sequences of ancient hominin proteins fairly easily, because they already have DNA from Neanderthals, Denisovans and H. sapiens. This allows them to predict the protein sequences that are likely to appear in their mass-spectrometry signals. “You can identify fragments you expect to be there from known genome sequences, from either ancient organisms or present-day people, and look for them,” says Svante P??bo, a palaeogeneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.But as scientists look further back in time, they will need to work out the sequence of those amino acids without a map. That’s an ongoing challenge for ancient proteomics, because proteins are degraded into small fragments, and samples are often contaminated with modern proteins, P??bo says.Collins is confident that it can be done. He points to a 2015 paper9 in which he, Welker and others mapped out the phylogenetic tree for South America’s native ungulates, a varied group of peculiar-looking mammals that went extinct around 12,000 years ago. With no DNA available from ungulate fossils, the team had to sequence collagen proteins from scratch to compare them with those of other animals. They found that two extinct native ungulates, Toxodon and Macrauchenia, were closely related to a group that includes horses and rhinos — and not, as some researchers had thought, the group Afrotheria, which includes elephants and manatees.Other limitations are more fundamental. Ancient teeth and bones contain a small number of proteins, so there are relatively few chunks of information that can be used to identify a specimen. Analysis of the Tibetan Denisovan, for example, revealed sequences from eight different kinds of collagen protein, totalling slightly more than 2,000 amino acids. Just one of these amino acids differed from Neanderthal and modern human sequences, identifying the sample as Denisovan. That means that even if a researcher were able to sequence the proteins from a H. erectus specimen, for instance, there simply might not be enough information in the amino-acid sequences to say anything definitive about its relationship to modern or archaic humans. By comparison, a single ancient genome contains in the order of three million variants compared with any other genome, says Skoglund, and so is much more informative regarding evolution.And because proteins often perform crucial functions — forming the structure of bone, say — they don’t always change much as species evolve. Proteins that are specific to enamel, for instance, are exactly the same in Denisovans, H. sapiens and Neanderthals, so can’t be used to distinguish between these groups. Welker says, however, that these proteins do vary in other great apes, and could be more informative when it comes to older hominin groups.Still, researchers know very little about how protein sequences vary in populations of ancient humans. Scientists have sequenced only a single Denisovan genome, for example, which means that to identify the Tibetan Denisovan, the team compared the protein sequences to just one other member of that group. It could be that other Denisovans had different variants. “Many geneticists are quite sceptical of the methodology, but I think it’s because they have come a long way in understanding genomic variation in ancient populations,” says Douka.Learning from the pastThere are other challenges, too. Some researchers are concerned that the broader buzz around palaeoproteomics could result in the field falling into the same traps as the ancient-DNA field did 20 years ago. Many apparently exciting results from the 1990s and early 2000s — the discovery of DNA from dinosaurs or insects trapped in amber, for example — later turned out to be false because they were products of contamination or other methodological errors. “I wouldn’t be surprised if this happens to the proteomics world,” says Douka.Those leading the way in the field are aware of these problems, and many researchers are making concerted efforts to create a robust science. Among them is Jessica Hendy, an archaeologist at the University of York, UK, who is pioneering the use of proteins to study the diet of early humans. In a 2018 paper, Hendy and her colleagues identified proteins in 8,000-year-old ceramics from ?atalh?yük in modern-day Turkey, which revealed that the ancient inhabitants ate various plants and animals, and even processed milk into whey10.“This technique is so interesting and so fascinating and is really getting a lot of attention, especially right now,” Hendy says. “We really need to be moving carefully,” she adds. Together with Welker, Hendy is lead author on a paper outlining best practices for the field, from avoiding contamination to sharing data in public repositories11.Hendy adds that there needs to be more basic research into how proteins survive and degrade over long timescales. This kind of research might not make headlines, she says, but can give researchers much more confidence in their results. She points to Demarchi’s work as an example: Demarchi found that the proteins in her 3.8-million-year-old eggshell had bound to the surface of the mineral crystals in the shell, essentially freezing them in place. “What’s cool about that is that it’s actually explaining why the proteins are surviving, which makes the finding so much more robust,” says Hendy.Even though there are still issues to sort out, progress in the field shows no signs of slowing. And whereas human evolution might get the most attention, scientists are using ancient proteomics in all kinds of ways, from studying markers of disease in the tartar of ancient teeth12, to investigating which animal skins were used to create medieval parchments13.Demarchi says she is excited by it all. And when it comes to working out the family trees of long-extinct organisms, she says, proteomics has the potential to make waves. “I don’t think I’ll see the end of it in my lifetime,” she says. “It’s going to be really quite big”.References1. Chen, F. et al. Nature 569, 409–412 (2019).2. Meyer, M. et al. Nature 531, 504–507 (2016).3. Brown, S. et al. Sci. Rep. 6, 23559 (2016).4. Welker, F. et al. Proc. Natl Acad. Sci. USA 113, 11162–11167 (2016).5. Détroit, F. et al. Nature 568, 181–186 (2019).6. Cappellini, E. et al. Preprint at bioRxiv (2018).7. Rybczynski, N. et al. Nature Commun. 4, 1550 (2013).8. Demarchi, B. et al. eLife 5, e17092 (2016).9. Welker, F. et al. Nature 522, 81–84 (2015).10. Hendy, J. et al. Nature Commun. 9, 4064 (2018).11. Hendy, J. et al. Nature Ecol. Evol. 2, 791–799 (2018).12. Jersie-Christensen, R. R. et al. Nature Commun. 9, 4744 (2018).13. Fiddyment, S. et al. Proc. Natl Acad. Sci. USA 112, 15066–15071 (2015).Wei, J., Liang, J., Lu, J., Zhang, W., He, Y., 2019. Characteristics and dynamics of gas hydrate systems in the northwestern South China Sea - Results of the fifth gas hydrate drilling expedition. Marine and Petroleum Geology 110, 287-298. 2018, Guangzhou Marine Geological Survey conducted the fifth gas hydrate drilling expedition (GMGS5) in the northwestern continental slope of South China Sea. We use pore water geochemistry, pressure core CT scanning, degassing quantification, seismic data and in situ temperature test at four drill sites (W01, W07, W08 and W09) to investigate the gas hydrate characteristics and discuss the dynamics of the gas hydrate system. Based on the CT scanning and pressure core degassing, we demonstrate the coexistence of pore-filling and vein-like gas hydrates. Gas hydrate saturation estimated based on the chloride concentration (0–92%) is higher than that based on the degassing quantification (0–52.9%). The saturation discrepancy is mainly resulted from the sampling discrimination. Based on the average gas hydrate saturation estimated using chloride concentration and degassing, the methane gas volume contained in the gas hydrate of one cubic meter sediment at drill sites W07, W08 and W09 are calculated to be 13.7?m3, 26.82?m3 and 22.24?m3 and 3.03?m3, 14.30?m3 and 16.25?m3. The geothermal gradients estimated based on the in situ temperature measurements at sites W07, W08 and W09 (102–111?°C/km) are more than 50% higher than that at the background site W01 (65?°C/km). It is inferred that the fractures and faults in the gas chimney at sites W07, W08 and W09 are the major contributors for the efficient fluid pathways and high geothermal gradients. The pore water sulfate profiles and inferred sulfate-reduction methane-oxidation interface (SMI) depths indicate that methane flux is lowest at site W01 and highest at site W08. The SMI depths and top of gas hydrate occurrence is linearly correlated which provides an experienced function for understanding the local gas hydrate distribution. Kick-type sulfate profiles at sites W07 and W09 indicate an ongoing increase of methane flux and corresponding shoaling SMI depths. In addition, chloride enrichment in the shallow sediment at site W08 indicates a recent fast gas hydrate formation process. The kick-type sulfate profiles, positive chloride anomalies and authigenic carbonates at multiple depths suggest that the system experienced dynamic changes in fluid flux and multi-stage gas hydrate evolution on time scale from months to thousands of years. Understanding the controlling mechanism and periodicity of the composite pressure system is important for evaluating the gas hydrate resource and carbon cycling.Weiss, G.M., de Bar, M.W., Stolwijk, D.J., Schouten, S., Sinninghe Damsté, J.S., van der Meer, M.T.J., 2019. Paleosensitivity of hydrogen isotope ratios of long-chain alkenones to salinity changes at the Chile Margin. Paleoceanography and Paleoclimatology 34, 978-989. isotope ratios of long‐chain alkenones (δ2HC37 ratios) have been shown to correlate with salinity in several culture studies. However, it is uncertain how applicable the δ2HC37‐salinity relationship is to reconstruct past salinity. The δ2HC37 ratios were measured on sediments from a drill core (ODP site 1234) at the Chilean Margin covering the last ~150 kyr. High δ2HC37 values corresponded to glacial time periods and interglacial periods are characterized by lower δ2HC37 values, aligning with δ18O ratios measured on planktonic foraminifera from the same core. Effects of parameters such as species composition, the δ2H‐δ18O relationship used for ice volume corrections, and nutrient‐ or light‐controlled growth rate, did not appear to significantly alter δ2HC37 ratios at ODP 1234. We used linear regression equations from batch culture experiments, marine surface sediments, and suspended particulate organic matter to quantitatively characterize salinity changes over the last ~150 kyr at ODP 1234. However, most of these equations yielded larger salinity shifts than previously suggested, a phenomenon also observed for other δ2HC37 records. This suggests that the paleosensitivity of δ2HC37 ratios to salinity was larger in the geologic record than has been observed in any modern environment or laboratory settings, or that glacial to interglacial salinity shifts might have been larger than currently believed.White, H.K., Marx, C.T., Valentine, D.L., Sharpless, C., Aeppli, C., Gosselin, K.M., Kivenson, V., Liu, R.M., Nelson, R.K., Sylva, S.P., Reddy, C.M., 2019. Examining inputs of biogenic and oil-derived hydrocarbons in surface waters following the Deepwater Horizon oil spill. ACS Earth and Space Chemistry 3, 1329-1337. hydrocarbons in the surface ocean are derived from phytoplankton and oil, but the coexistence and cycling of these two sources is not well-defined. Moreover, phytoplankton and oil can create thin layers of a nonmiscible phase that appear as sheens on surface water and are visually difficult to distinguish. Here, we examine the co-occurrence of hydrocarbon compounds in surface water samples to determine the inputs from phytoplankton and oil using pentadecane (C15-n-alkane) and heptadecane (C17-n-alkane) as molecular markers. Surface water sheens collected from a 2015 field survey in the Northern Gulf of Mexico contained hydrocarbons from natural oil seepage, phytoplankton blooms (i.e., biogenic), and mixtures of the two. Microbial communities examined in surface water sheen samples were dominated by cyanobacteria of the Genus Trichodesmium. The hydrocarbon content of the field-collected surface sheens was used to inform the categorization of 2171 samples collected in 2010 during the Deepwater Horizon (DWH) oil spill. Of the water samples categorized, a small fraction (<1%) contained only biogenic hydrocarbons, and ～10% contained a biogenic-hydrocarbon input mixed with oil. This study provides a method for identifying biogenic inputs to oil slicks and surface sheens, and highlights a molecular approach to distinguish the two sources.Wijayanto, T., Kurihara, M., Kurniawan, T., Muraza, O., 2019. Experimental investigation of aluminosilicate nanoparticles for enhanced recovery of waxy crude oil. Energy & Fuels 33, 6076-6082., research on cost-effective nanoparticles for improved and enhanced oil recovery has attracted increasing attention. Most of the existing research activities on the effects of nanofluids were focused on the alteration of wettability and the reduction of interfacial tension. However, in those studies, the nanoparticle solutions were presumably composed of not only bare nanoparticles but also with stabilizers or surfactants. It becomes ambiguous which components in the nanoparticle solutions played a role. In this work, we used a waxy crude oil and aluminosilicate nanoparticle to resolve the ambiguity. The objective of this work is to investigate the oil displacement mechanism by nanofluid through the measurements of the wettability index and interfacial tension as well as through core-flooding experiments. These experimental results showed that aluminosilicate nanoparticles could alter the rock surface wettability from water-wet to stronger water-wet and decrease the interfacial tension between oil and injection fluid. On the basis of the results, the effects of aluminosilicate injection on the improvement of oil recovery were confirmed, which suggests that aluminosilicate nanoparticles can increase the recovery of paraffinic oil with an asphaltene content of 25% in a water-wet reservoir.Willyard, K.A., Schade, G.W., 2019. Flaring in two Texas shale areas: Comparison of bottom-up with top-down volume estimates for 2012 to 2015. Science of The Total Environment 691, 243-251. advances in horizontal drilling and hydraulic fracturing technologies have opened oil and gas development in previously unreachable areas, air pollution emissions have increased from the burning (i.e., flaring) or releasing (i.e., venting) of natural gas at oil and gas extraction sites. While venting and flaring is a growing concern, accounting of how much gas is vented and flared, and where this occurs, remains limited. The purpose of this paper is to describe two methods for estimating venting and flaring volumes - self-reports required by state law and satellite imagery radiant heat measurements - and to compare these methods using the case of Texas Eagle Ford and Permian Basin venting and flaring practices from 2012 to 2015. First, we used data self-reported by companies to the Texas Railroad Commission (TxRRC), and National Oceanic and Atmospheric Administration (NOAA) data captured by satellite-based Visible Infrared Imaging Radiometer Suite sensors, to estimate the annual total volumes of gas vented and flared in the Eagle Ford and Permian Basin from 2012 to 2015. Next, we developed a method using a geographic information system to link and compare TxRRC and NOAA county-based and point-based volume estimates. Finally, we conducted case studies of two oil and gas fields to better understand how TxRRC and NOAA venting and flaring volumes differ. We find both TxRRC and NOAA estimated venting and/or flaring volumes steadily increased from 2012 to 2015. Additionally, TxRRC reports captured about half the volumes estimated by NOAA. This suggests that self-reported volumes significantly underestimate the volume of gas being vented or flared. However, this research is limited by the data currently available. As such, future research and policy should further develop methods to systemically capture the extent to which oil and gas extraction facilities vent and flare natural gas.Wilpiszeski, R.L., Aufrecht, J.A., Retterer, S.T., Sullivan, M.B., Graham, D.E., Pierce, E.M., Zablocki, O.D., Palumbo, A.V., Elias, D.A., 2019. Soil aggregate microbial communities: towards understanding microbiome interactions at biologically relevant scales. Applied and Environmental Microbiology 85, e00324-19. contain a tangle of minerals, water, nutrients, gases, plant roots, decaying organic matter, and microorganisms which work together to cycle nutrients and support terrestrial plant growth. Most soil microorganisms live in periodically interconnected communities closely associated with soil aggregates, i.e., small (&amp;lt;2?mm), strongly bound clusters of minerals and organic carbon that persist through mechanical disruptions and wetting events. Their spatial structure is important for biogeochemical cycling, and we cannot reliably predict soil biological activities and variability by studying bulk soils alone. To fully understand the biogeochemical processes at work in soils, it is necessary to understand the micrometer-scale interactions that occur between soil particles and their microbial inhabitants. Here, we review the current state of knowledge regarding soil aggregate microbial communities and identify areas of opportunity to study soil ecosystems at a scale relevant to individual cells. We present a framework for understanding aggregate communities as “microbial villages” that are periodically connected through wetting events, allowing for the transfer of genetic material, metabolites, and viruses. We describe both top-down (whole community) and bottom-up (reductionist) strategies for studying these communities. Understanding this requires combining “model system” approaches (e.g., developing mock community artificial aggregates), field observations of natural communities, and broader study of community interactions to include understudied community members, like viruses. Initial studies suggest that aggregate-based approaches are a critical next step for developing a predictive understanding of how geochemical and community interactions govern microbial community structure and nutrient cycling in soil.Wolkenstein, K., 2019. Characterization of polycyclic aromatic hydrocarbons and their phenanthroperylene quinone precursors in fossil crinoids using liquid chromatography–atmospheric pressure photoionization mass spectrometry. Organic Geochemistry 136, 103892. distribution and origin of diagenetic products of polycyclic quinone pigments in fossil crinoids was investigated using high-performance liquid chromatography–diode array detection–atmospheric pressure photoionization mass spectrometry (HPLC–DAD–APPI-MS). A number of characteristic higher-molecular-weight polycyclic aromatic hydrocarbons (PAHs) were identified in toluene extracts of diverse crinoid samples, with 1,2,3,4,5,6-hexahydrophenanthro[1,10,9,8-opqra]perylene as the main compound. Moreover, phenanthro[1,10,9,8-opqra]perylene-7,14-dione (PPQ) and further derivatives were detected for the first time in the fossil record, representing intermediates between hydroxylated phenanthroperylene quinone pigments such as fringelite F and phenanthroperylene PAHs. The widespread presence of PPQ, its derivatives and related PAHs in fossil crinoids which contain phenanthroperylene quinone pigments confirms the diagenetic formation of specific PAHs by reductive degradation of quinone pigments.W?rndle, S., Crockford, P.W., Kunzmann, M., Bui, T.H., Halverson, G.P., 2019. Linking the Bitter Springs carbon isotope anomaly and early Neoproterozoic oxygenation through I/[Ca?+?Mg] ratios. Chemical Geology 524, 119-135. ca. 810?Ma Bitter Springs carbon isotope anomaly is an abrupt and long-lived (5–10 Myr.) departure from the positive carbon isotope values (δ13Ccarb) that otherwise characterize early-middle Neoproterozoic carbonate rocks. The onset of this isotope anomaly is manifested by a globally expressed ~8‰ negative shift in δ13C values in shallow marine carbonate strata. Given increasing evidence that metazoan diversification began well before the Ediacaran Period, the Bitter Springs anomaly is a logical interval to explore the potential relationship between biological innovation, perturbations to the carbon cycle, and oxygenation. The iodine-to-calcium+magnesium ratio (I/[Ca?+?Mg]) in marine carbonates is a sensitive proxy for seawater redox conditions that is increasingly being applied to reconstruct the oxygenation of the global surface ocean through Earth's history. We report I/[Ca?+?Mg] ratios, along with carbon and oxygen isotope ratios and major and minor element concentrations from carbonate sections spanning the Bitter Springs anomaly in Svalbard, East Greenland, and the Mackenzie Mountains (northwestern Canada). The results from Svalbard and Greenland collectively show two prominent features. The early stage of the Bitter Springs anomaly is characterized by a negative δ13C shift coupled to low I/[Ca?+?Mg] ratios compared to carbonates pre- and post-dating the Bitter Springs anomaly. The last stage of the Bitter Springs anomaly displays a positive excursion in I/[Ca?+?Mg], with the highest values at ~7?μmol/mol yet documented in rocks older than 580?Ma. In contrast, carbonates from the Mackenzie Mountains are uniformly low and display no variation in I/[Ca?+?Mg] across the Bitter Springs anomaly, which we interpret to be the consequence of alteration of primary signatures during diagenesis. The observed geochemical variations in our Svalbard and Greenland datasets are interpreted to be the result of a shift from pre-Bitter Springs ocean conditions, defined by well oxygenated surface waters and anoxic-ferruginous bottom waters, to syn-Bitter Springs ocean conditions, characterized by expanded euxinia.Wu, J.-H., He, C.-Y., 2019. Advances in cellulose-based sorbents for extraction of pollutants in environmental samples. Chromatographia 82, 1151-1169. effective extraction and detection of pollutants in the environment have been important issues in analytical science. Cellulosic materials, composed of both functionalized and composited components, have been recently identified as promising solid-phase extraction adsorbents for various applications. Due to their alluring properties such as renewability, biodegradability, biocompatibility, high strength and stiffness and easy modification, this unique class of materials exhibits excellent extraction and enrichment performance for numerous target analytes. Herein, we review recent significant advances in solid-phase extraction using cellulosic sorbents for organic and inorganic pollutants in environmental matrices. The development of new cellulose-based sorbents and related solid-phase extraction (SPE) patterns, including cartridge SPE (c-SPE), disk SPE, dispersive SPE, magnetic SPE, molecularly imprinted SPE, on-line SPE, SPE spectroscopy/spectrometry and thin film microextraction (TFME), were discussed in this review.Wu, X., Liu, Q., Liu, G., Ni, C., 2019. Genetic types of natural gas and gas-source correlation in different strata of the Yuanba gas field, Sichuan Basin, SW China. Journal of Asian Earth Sciences 181, 103906. chemical compositions and stable carbon and hydrogen isotopic compositions of natural gases in different strata of the Yuanba gas field in the Sichuan Basin were analyzed to investigate their genetic types and source. Natural gases from the Permian Changxing and Triassic Feixianguan formations have dryness coefficients higher than 0.995 and contain H2S in most gas samples, having a positive correlation between the H2S and CO2 contents. The identification of gas origin and gas-source correlation from this study indicate that natural gas in the Ziliujing Formation and most gas samples from the Xujiahe Formation are coal-type gas produced from primary cracking of kerogen, and they are self-sourced reservoirs in relatively independent systems. The natural gases in the 1st and 2nd members of the Xujiahe Formation were mixed with minor amounts of oil-type gas from argillaceous carbonate rocks in the Leikoupo Formation. In addition to the self-accumulated oil-type gas in the Leikoupo Formation, natural gas mainly came from the overlying or lateral source rocks in the Xujiahe Formation. The H2S-bearing natural gases in the Changxing and Feixianguan formations were produced by the cracking of crude oil from source rocks in the underlying Wujiaping Formation, with partial contributions from certain local source rocks in the Permian Dalong Formation. The H2S-bearing natural gas has undergone the thermochemical sulfate reduction (TSR) which were dominated by heavy hydrocarbons. The high δ13C values of CO2 in these gas reservoirs mainly result from the interaction between acidic fluids and carbonate rocks in the reservoirs.Wu, Z., Mao, Y., Raza, M., Zhu, J., Feng, Y., Wang, S., Qian, Y., Yu, L., Lu, X., 2019. Surrogate fuels for RP-3 kerosene formulated by emulating molecular structures, functional groups, physical and chemical properties. Combustion and Flame 208, 388-401. objective of the current study was to formulate RP-3 kerosene surrogate by emulating fuel properties affecting the physical and chemical processes of the target fuel under the engine relevant conditions. This study utilized two-dimensional gas chromatography with time-of-flight mass spectrometry (GC ?×? GC-TOFMS) and 13C and 1H nuclear magnetic resonance (NMR) spectroscopy to characterize the compositional characteristics of RP-3 fuel, and various standard test methods were applied to measure the physical and chemical properties of the target fuel. Two surrogate fuels (K1, a mixture of five components and K2, a mixture of seven components) were optimally determined through a multi-property regression algorithm by matching carbon types (CTs), distillation curve, cetane number (CN), density, and threshold sooting index (TSI) of the target fuel. The measured and estimated values of both target properties and non-target properties of surrogates were validated against the experimental data of RP-3 kerosene. Ignition delay times (IDTs) of both surrogates were investigated in a heated shock tube and a heated rapid compression machine under engine relevant conditions and validated against the measured results of RP-3. Overall, K1 and K2 both exhibited good matching on the compositional characteristics, physical-chemical properties, and gas phase ignition behaviors with the target fuel. In contrast, the seven-component K2 was more competitive and more comprehensive.Xiao, L., Wei, W., Luo, M., Xu, H., Feng, D., Yu, J., Huang, J., Liu, F., 2019. A potential contribution of a Fe(III)-rich red clay horizon to methane release: Biogenetic magnetite-mediated methanogenesis. CATENA 181, 104081. to prior laboratory research evidence, the formation of a conductive secondary mineral to accelerate electron transfer is an important factor in methanogenesis. However, the promotion of methanogenesis by a secondary mineral is rarely found in the in situ terrestrial ecosystem. In this study, soil samples with a depth profile were collected from a wetland in the Yellow River Delta (YRD), in which a special red clay horizon (RCH) widely exists. By analysing the soil physicochemical properties and microbial diversity, we demonstrate that the RCH is distinguished from its upper and lower layers by increased iron oxides and a higher abundance and diversity of electrogenic bacteria and methanogens. Further experimental results demonstrate that the RCH soil presented the lowest level of iron reduction ability and the highest methane production rate. Meanwhile, the precipitation of magnetite appeared in the treatment with the RCH soil as an inoculum. In the third generation of the RCH enrichment, the iron reduction ability was further suppressed, and the methane production rate was increased. Accordingly, changes to the microbial community structure were observed, manifested as a marked increase in the abundance of bacteria with the capacity to release electrons, such as Thermincola, Rombotusia, and Shewanella, as well as Methanosarcina, an archaea known as an electron-accepting methanogen. This study suggests that the RCH benefits the syntrophy between electron-donating and electron-accepting partners with the assistance of biologically diagenetic magnetite. To our knowledge, this is the first exploration for the promotion of methanogenesis by a biogenic mineral in the in situ critical zone.Xu, S., Feng, Q., Wang, S., Li, Y., 2019. A 3D multi-mechanistic model for predicting shale gas permeability. Journal of Natural Gas Science and Engineering 68, 102913. gas reservoir consists of multiple media, including organic matter, inorganic matrix, and natural fracture. The flow of methane in shale system exhibits multiple mechanisms, such as Knudsen diffusion, surface diffusion, adsorption, and phase behavior. However, previous studies don't take these factors into account simultaneously to predict shale gas permeability. Here, we develop a 3D multi–mechanistic model to overcome this drawback. Using a classification algorithm, we first divide two pore size distributions (PSDs) of organic and inorganic pores. Then we measure the gas permeabilities of different pore spaces, respectively. Regarding organic pores, we consider Knudsen diffusion, surface diffusion, and adsorption. For inorganic pores, we only take Knudsen diffusion into account. Both models consider real gas effect and phase behavior. In natural fractures, we use Poiseuille law to obtain fracture permeability. After that, on the basis of embedded discrete fracture model (EDFM), we incorporate the effect of three pore types (natural fracture, organic and inorganic pores) to measure shale gas permeability. To verify the reliability of our model, we compare the result with the data from documented studies. Through sensitivity analysis, we can draw several conclusions as follows. Natural fracture has the greatest impact on permeability, followed by inorganic pore and organic pore. Owing to the horizontally oriented natural fractures, the permeability in horizontal direction is typically higher than that in vertical direction. As the inorganic pore size increases, permeability increases. While increasing organic pore size, the overall permeability will first drop and then pick up. The difference of the overall permeability caused by phase behavior and real gas effect is minor. Our proposed model can be used as an effective and comprehensive tool to predict shale gas permeability.Yan, D., Chen, D., Wang, Z., Li, J., Yang, X., Zhang, B., 2019. Climatic and oceanic controlled deposition of Late Ordovician-Early Silurian black shales on the North Yangtze platform, South China. Marine and Petroleum Geology 110, 112-121. shales deposited across the Late Ordovician and Early Silurian transition are considered to be the most important source rock and shale gas reservoirs in the Yangtze region of South China. However, the origin of these sediments remains contentious. In this study, we investigated the systematic changes in total organic carbon (TOC), organic carbon isotopes (δ13Corg), major elements and trace elements on the Ordovician-Silurian boundary strata from Qiaoting, North Yangtze Sea, to reconstruct the climatic conditions, redox changes, primary productivity, and other factors there, promoting the understanding for the formation mechanism of the organic-rich black shales. Element compositions and their ratios suggest that the black shales studied here were dominantly sourced by the felsic igneous rock, which is similar to granodiorite in composition. Paleoclimatic proxies (CIA, CIW, δ13Corg) suggest that the global climate system experienced significant changes from warm-humid to cold-dry and then to warm-humid climates during the Ordovician-Silurian transition. Paleoredox indices (S/C, U/Th, Ni/Co and V/(V + Ni) ratios) also demonstrate fluctuating redox variations from anoxic to oxygenated, and then to anoxic states during this interval in the Yangtze Sea, which describe an oxygenated Guanyinqiao strata sandwiched between the stagnant and anoxic Wufeng and Longmaxi black shales. Paleoproductivity parameters (TOC, Babio contents and P/Al ratio) suggest that the organic-rich Wufeng and Longmaxi black shales, were deposited with a high biological productivity, while the organic-lean Guanyinqiao sediments were deposited with a low biological productivity. These data demonstrate large climatic and oceanic fluctuations during the Ordovician-Silurian transition, providing essential controlling factors on the oceanic anoxia, primary productivity, and subsequent organic-rich black shale depositions in the Yangtze region during the Late Ordovician and Early Silurian intervals.Yang, C., Zhang, G., Serhan, M., Koivu, G., Yang, Z., Hollebone, B., Lambert, P., Brown, C.E., 2019. Characterization of naphthenic acids in crude oils and refined petroleum products. Fuel 255, 115849. acids (NAs) or naphthenic acid fraction compounds (NAFCs) are generally recognized as a family of cycloaliphatic carboxylic acids naturally occurring in petroleum. These acid extractable organics (AEOs) from petroleum industry activities including oil sands produced waters (OSPW) have led to increasing environmental concern in recent years due to their potential release into the environment. This study presents a characterization of naphthenic acids in a number of crude oils and refined petroleum products from various sources. NAs with unsaturated degree of z ?2 to z ?24 and carbon number ranging from 6 to 60 were determined by liquid chromatography-high resolution Orbitrap mass spectrometry (LC-HRMS). NA profiles generally vary from oil to oil. Conventional light crude oils generally contain low concentrations of NAs, while heavier crudes and oil sands bitumen contain significant levels of NAs. NAs in Federated and Alaska North Slope crude oils are relatively low with O2-NA concentrations of 139??g/g and 419??g/g, respectively, while their abundances are as high as 7994??g/g in Venezuelan Orinoco bitumen. The ratio of even to odd (E/O) carbon number NAs in all petroleum oils studied is close to 1.0 for z ?2 to z ?24 NAs. NA series z 0 to z ?12 in bitumen account for about 90% of the total determined NAs, and z ?14 to z ?24 NAs make up the remaining ～10%. Moreover, z ?2～?6 (1- to 3-ring) NAs are the most predominant in all oil samples. In terms of distribution according to carbon number, C6 to C21 NAs (α-group) make up about 44.2% of the total NAs in an Alberta oil sands bitumen. Caustic extraction of oil sands bitumen mostly transports the more toxic low-molecular weight portion of NAs into OSPW, in which α-group NAs constitute about 90% of the total NAs. Evaporation (up to 23.6% by weight) weathering slightly enriched the NAs but likely did not affect the distribution profile of NAs in a diluted bitumen (dilbit).Yang, J., Junium, C.K., Grassineau, N.V., Nisbet, E.G., Izon, G., Mettam, C., Martin, A., Zerkle, A.L., 2019. Ammonium availability in the Late Archaean nitrogen cycle. Nature Geoscience 12, 553-557. bioavailability of essential nutrients such as nitrogen and phosphorus has fluctuated with the chemical evolution of Earth surface environments over geological timescales. However, significant uncertainty remains over the evolution of Earth’s early nitrogen cycle, particularly how and when it responded to the evolution of oxygenic photosynthesis. Here we apply multi-proxy geochemical analyses (Fe speciation, δ13C and δ15N) to exceptionally well-preserved shales from the approximately 2.7?billion year old Manjeri Formation in the Belingwe Greenstone Belt, Zimbabwe, to evaluate the redox status of Earth’s early nitrogen cycle and decipher feedbacks associated with the initial stages of planetary oxygenation. These continental shelf sediments were previously linked to early cyanobacterial oxygen production, and provide a direct test of conflicting hypotheses concerning the importance of nitrogen oxyanions in the Late Archaean era. Our data reveal a dominantly anaerobic marine nitrogen cycle in which ammonium-replete ferruginous waters underlay an ephemeral oxygen oasis. Driven by the emergence of oxygenic photosynthesis, increased primary productivity could have periodically strengthened export production, which allowed for the accumulation of ammonium in the water column during organic matter degradation. Restricted oxygen availability could have allowed the upwelling ammonium to reach the photic zone to provide ample nitrogen to fuel a prolific Late Archaean biosphere.Yastrebova, O.V., Pyankova, A.A., Plotnikova, E.G., 2019. Phthalate-degrading bacteria isolated from an industrial mining area and the processing of potassium and magnesium salts. Applied Biochemistry and Microbiology 55, 397-404. have identified 25 halotolerant strains of ortho-phthalic acid (OPC) decomposer bacteria from samples of soil, sludge, and bottom sediments taken in the area of salt mining enterprises of Uralkalij (Berezniki, Russia). Based on an analysis of the 16S rRNA gene, the isolates were assigned to the genera Rhodococcus, Dietzia, Bacillus, Halomonas, Pseudomonas, Idiomarina, Stappia, Martelella, Erythrobacter, Alcanivorax, Marinobacter, Oceanisphaera, Nitratireductor, and Breoghania. Eight OPC decomposer strains are capable of using the phthalic acid esters Dibutyl phthalate (DBP) and Diethyl phthalate (DEP) as the sole source of carbon and energy. The strains utilized 90–98% of DBP and 49–80% of DEP (the phthalate concentration is 500 mg/L), both in the absence of NaCl in the cultivation medium and with a concentration in the medium of 50 g/L. An increase in the NaCl concentration in the medium to 70 and 90 g/L did not significantly affect the utilization of phthalates. The ability of bacteria of the genera Halomonas, Martelella, and Oceanisphaera to decompose DEF and DBP has been shown for the first time. Isolated phthalate (OPC, DEP and DBP) decomposer strains are promising for the development of new methods for the bioremediation of saline soils contaminated with phthalates.Ye, L., Chen, H., Jing, C., 2019. Sulfate reducing bacteria mobilize adsorbed antimonate by thioantimonate formation. Environmental Science & Technology Letters 6, 418-422. biogeochemical cycling of antimony (Sb) is often coupled with sulfur and sulfate-reducing bacteria (SRB). The biogenic sulfide is usually assumed to facilitate Sb immobilization via Sb2S3 precipitation. Here, to the contrary, we discovered that SRB mobilize adsorbed Sb(V). When SbV(OH)6--bearing goethite was incubated anaerobically with Desulfovibrio vulgaris DP4, elevated antimony was released due to the formation of thioantimonate which is the dominant Sb species in solution. Our fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis observed multiple six- or five-coordinate thioantimonate intermediates, suggesting stepwise ligand exchange of hydroxyl groups on SbV(OH)6- by biogenic sulfide. Direct H2S elimination reactions resulted in four-coordinate thioantimonate species as the stable end product, which was confirmed by our density functional theory (DFT) calculations. The thiolation of antimonate is pH-dependent and occurs in neutral environments. The thiolation changed Sb(V) from six-coordinate octahedral to four-coordinate tetrahedral coordination, weakening its affinity for iron oxides and thus facilitating its release into the aquatic environment. The results of this study highlight the importance of biogenic sulfide produced by SRB on the fate and transport of Sb.Yin, L., Guo, S., 2019. Full-sized pore structure and fractal characteristics of marine-continental transitional shale: a case study in Qinshui Basin, North China. Acta Geologica Sinica - English Edition 93, 675-691. on 10 shale samples collected from 4 wells in Qinshui Basin, we investigate the full‐sized pore structure and fractal characteristics of Marine‐Continental transitional shale by performing organic geochemistry, mineralogical composition, Nitrogen gas adsorption (N2 adsorption) and Nuclear Magnetic Resonance (NMR) measurements and fractal analysis. Results show that the TOC content of the shale samples is relatively high, with an average value of 2.44wt%, and the thermal evolution is during the mature‐over mature stage. The NMR T2 spectrum can be used to characterize the full‐sized pore structure characteristics of shale. By combining N2 adsorption pore structure parameters and NMR T2 spectrums, the surface relaxivity of samples are calculated to be between 1.7877 um/s and 5.2272 um/s. On this basis, the T2 spectrums are converted to full‐sized pore volume and surface area distribution curves. The statistics show that the pore volume is mainly provided by mesopore, followed by micropore, and the average percentages are 65.04% and 30.83% respectively; the surface area is mainly provided by micropore, followed by mesopore, and the average percentages are 60.8004% and 39.137% respectively; macropore contributes little to pore volume and surface area. The pore structure characteristics of shale have no relationship with TOC, but strong relationships with clay minerals content. NMR fractal dimensions Dmicro and Dmeso have strong positive relationships with the N2 adsorption fractal dimensions D1 and D2 respectively, indicating that Dmicro can be used to characterize the fractal characteristics of pore surface, and Dmeso can be used to characterize the fractal characteristics of pore structure. The shale surface relaxivity is controlled by multiple factors. The increasing of clay mineral content, pore surface area, pore surface fractal dimension and the decreasing of average pore size, will all lead to the decreasing of shale surface relaxivity.Yin, X., Wu, W., Maeke, M., Richter-Heitmann, T., Kulkarni, A.C., Oni, O.E., Wendt, J., Elvert, M., Friedrich, M.W., 2019. CO2 conversion to methane and biomass in obligate methylotrophic methanogens in marine sediments. The ISME Journal 13, 2107-2119. substrates are important compounds for methanogenesis in marine sediments but diversity and carbon utilization by methylotrophic methanogenic archaea have not been clarified. Here, we demonstrate that RNA-stable isotope probing (SIP) requires 13C-labeled bicarbonate as co-substrate for identification of methylotrophic methanogens in sediment samples of the Helgoland mud area, North Sea. Using lipid-SIP, we found that methylotrophic methanogens incorporate 60–86% of dissolved inorganic carbon (DIC) into lipids, and thus considerably more than what can be predicted from known metabolic pathways (~40% contribution). In slurry experiments amended with the marine methylotroph Methanococcoides methylutens, up to 12% of methane was produced from CO2, indicating that CO2-dependent methanogenesis is an alternative methanogenic pathway and suggesting that obligate methylotrophic methanogens grow in fact mixotrophically on methyl compounds and DIC. Although methane formation from methanol is the primary pathway of methanogenesis, the observed high DIC incorporation into lipids is likely linked to CO2-dependent methanogenesis, which was triggered when methane production rates were low. Since methylotrophic methanogenesis rates are much lower in marine sediments than under optimal conditions in pure culture, CO2 conversion to methane is an important but previously overlooked methanogenic process in sediments for methylotrophic methanogens.Yu, X., Lee, K., Ulrich, A.C., 2019. Model naphthenic acids removal by microalgae and Base Mine Lake cap water microbial inoculum. Chemosphere 234, 796-805. acids (NAs) originate from bitumen and are considered a major contributor to acute toxicity in oil sands process-affected water (OSPW) produced from bitumen extraction processes. To reclaim oil sands tailings and remediate OSPW, in-pit fluid fine tailings can be water-capped as end pit lakes (EPL). Addressing NAs present in OSPW, either through removal, dilution or degradation, is an objective for oil sands reclamation. EPLs can remediate NAs through degradation or dilution or both. To assess and understand degradation potential, Chlorella kessleri and Botryococcus braunii were tested for their tolerance to, and ability to biodegrade, three model NAs (cyclohexanecarboxylic acid, cyclohexaneacetic acid, and cyclohexanebutyric acid). Water sourced from the industry's first EPL, the Base Mine Lake (BML), was used alone as an inoculum or co-cultured with C. kessleri to biodegrade cyclohexanecarboxylic acid and cyclohexanebutyric acid. All cultures metabolized the model compounds via β-oxidation. Biodegradation by the co-culture of C. kessleri and BML inoculum was most effective and rapid: the cyclohexaneacetic acid generated from cyclohexanebutyric acid could be further degraded by the co-culture, while the cyclohexaneacetic acid generated could not be consumed by pure algal cultures or BML inoculum alone. Adding C. kessleri greatly increased the diversity of the microbial community in the BML inoculum; many known hydrocarbon and NA degraders were identified from the 16S rRNA gene sequencing from this co-culture. This more diverse microbial community could have potential for EPL remediation.Yue, G., Wu, H., Yue, J., Li, M., Zeng, C., Liang, W., 2019. Adsorption measurement and dual-site Langmuir model II: Modeling and prediction of carbon dioxide storage in coal seam. Energy Exploration & Exploitation 37, 1268-1285. estimation of carbon dioxide adsorption capacity in coal seam is very important for planning the carbon dioxide storage efforts of carbon capture and storage technology; however, an appropriate model is needed to convert the measured adsorption quantity to absolute adsorption quantity. In this work, carbon dioxide adsorption behavior is demonstrated and accurately predicted under a wide range of temperature and pressure using the dual-site Langmuir model. This model sufficiently explains the laboratory measurements of carbon dioxide adsorption equilibrium data across critical points in coal. The results show that the isotherms crossover beyond the Gibbs excess maximum and higher temperatures now result in higher excess uptake at equivalent pressures. Adsorbed phase volume and gas phase density of carbon dioxide change with equilibrium temperature and pressure, and the contribution of the volume–density term for the absolute adsorption gradually becomes less pronounced as the temperature increases. If only the excess adsorption quantity is taken, the result is a very large underestimation of the contribution of adsorbed carbon dioxide to the total content. As the coal seam depth increases, the contribution rates of actual adsorbed carbon dioxide quantity to total carbon dioxide storage quantity gradually decrease; however, the contribution rates of free carbon dioxide phase content gradually increase. The method used herein, with limited formulas and fast computing solutions, provides accurate estimations of the true carbon dioxide storage, which will lay the foundation for the research and development of carbon capture and storage technology.Zagor??ak, R., Thomas, H.R., 2019. High-pressure CO2 excess sorption measurements on powdered and core samples of high-rank coals from different depths and locations of the South Wales coalfield. Energy & Fuels 33, 6515-6526. experimental analysis aimed at investigating the high-pressure (sub- and supercritical) CO2 sorption behavior on two high-rank coals of different sizes is presented in this paper. Coals from the same seam (9 ft seam) but from depths of 150 m [black diamond (BD) coal] and 550 m [Aberpergwm (AB) coal] and different locations of the South Wales (UK) coalfield, known to be strongly affected by tectonically developed fracture systems, are employed for that purpose. Hence, the sorption behavior of powdered (0.25–0.85, 2.36–4.0 mm) and core samples obtained from locations associated with the deformation-related changes is analyzed in this paper to assess the CO2 storage potential of such coals. The results show that the coals exhibit maximum adsorption capacities up to 1.93 mol/kg (BD coal) and 1.82 mol/kg (AB coal). No dependence of the CO2 maximum sorption capacity with respect to the sample size for the BD coal is observed, whereas for the AB coal the maximum sorption capacity is reduced by more than half between the powdered and core samples. The CO2 sorption rates on the BD coal decrease by a factor of more than 9 from 0.25–0.85 to 2.36–4.0 mm and then remain relatively constant with further increase in sample size. The opposite is observed for the AB coal where sorption rates decrease with increasing sample size, that is, reducing by a factor of more than 100 between the 0.25–0.85 mm and core samples. The differences in behavior are interpreted through the structure each coal exhibits associated with the burial depths and sampling locations as well as through the minor variations in ash contents. This study demonstrates that anthracite coals, having experienced sufficient deformation, resulting in changes in fracture frequency, can adsorb significant amounts of CO2, offering great prospect to be considered as a CO2 sequestration option.Zak, M., 2019. A model of emerging intelligence in Universe. International Journal of Astrobiology 18, 251-258. paper proposes a scenario of origin and emerging of intelligent life in Universe based upon the mathematical discovery of a new class of dynamical systems described by ordinary differential equation (ODE) coupled with their Liouville equation. These systems called self-controlled since the role of actuators is played by the probability produced by the Liouville equation. Following the Madelung equation that belongs to this class, non-Newtonian and quantum-like properties such as randomness, entanglement and probability interference typical for quantum systems have been described. At the same time, these systems expose properties of livings: decomposition into motor and mental dynamics, the capability of self-identification and self-awareness, as well as self-supervision. But the most surprising discovery is the existence of a special sub-class, in which the dynamical systems can violate the second law of thermodynamics, and that makes them different from both Newtonian and quantum physics. This sub-class should be associated with intelligent livings due to capability to move from disorder to order without external help. Based upon the mathematical discovery described above, one can assume that there are good chances that similar dynamical systems representing intelligent livings exist in real physical world. This provides a reason for a ‘rehabilitation’ of the Maxwell demon and put it into physics of intelligent systems. Indeed, the Maxwell demon is implemented by the feedback from the Liouville equation to the original ODE, while this feedback is capable to rearrange the probability distribution against the second law of thermodynamics. In addition to that, the same feedback removes the entropy paradox by explaining high order in our surrounding by ‘intelligent life support’. Two-steps transition: from the Newtonian physics to the linear model of life, and from the latter to the model of intelligent life are analysed. The first transition is triggered by the Hadamard instability of the Newtonian physics with respect to small random disturbances in linear terms of the Liouville feedback. The second transition is triggered by instability of linear model of life with respect to small random disturbances of non-linear terms of Liouville feedback. This transition could be implemented by such physical phenomena as shock waves or negative diffusion in probability space. Both transitions can be associated with catastrophe theory, in which sudden shifts in behaviour arises from small changes in parameters of the model. In view of the proposed model, possible competition between artificial and human intelligence are discussed.Zakharenko, A.S., Galachyants, Y.P., Morozov, I.V., Shubenkova, O.V., Morozov, A.A., Ivanov, V.G., Pimenov, N.V., Krasnopeev, A.Y., Zemskaya, T.I., 2019. Bacterial communities in areas of oil and methane seeps in pelagic of Lake Baikal. Microbial Ecology 78, 269-285. have assessed the diversity of bacteria near oil-methane (area I) and methane (area II) seeps in the pelagic zone of Lake Baikal using massive parallel sequencing of 16S rRNA, pmoA, and mxaF gene fragments amplified from total DNA. At depths from the surface to 100?m, sequences belonging to Cyanobacteria dominated. In the communities to a depth of 200?m of the studied areas, Proteobacteria dominated the deeper layers of the water column. Alphaproteobacteria sequences were predominant in the community near the oil-methane seep, while the community near the methane seep was characterized by the prevalence of Alpha- and Gammaproteobacteria. Among representatives of these classes, type I methanotrophs prevailed in the 16S rRNA gene libraries from the near–bottom area, and type II methanotrophs were detected in minor quantities at different depths. In the analysis of the libraries of the pmoA and mxaF functional genes, we observed the different taxonomic composition of methanotrophic bacteria in the surface and deep layers of the water column. All pmoA sequences from area I were type II methanotrophs and were detected at a depth of 300?m, while sequences of type I methanotrophs were the most abundant in deep layers of the water column of area II. All mxaF gene sequences belonged to Methylobacterium representatives. Based on comparative analyses of 16S rRNA, pmoA, and mxaF gene fragment libraries, we suggest that there must be a wider spectrum of functional genes facilitating methane oxidation that were not detected with the primers used.Zarfl, C., 2019. Promising techniques and open challenges for microplastic identification and quantification in environmental matrices. Analytical and Bioanalytical Chemistry 411, 3743-3756. are observed ubiquitously and in different environmental compartments ranging from marine waters and sediments to freshwater and terrestrial ecosystems including biota. Over the last decade, several methods have been applied and advanced to monitor and quantify microplastics, to identify the polymer material and to describe the particle properties, such as size, shape or colour. In most cases, the overarching aim is to elucidate patterns of occurrence that might result from (micro)plastic emissions and environmental fate. But the applied methods are subject to uncertainties and boundary conditions, be it spatial resolution that excludes the smallest microplastics or limitations in distinguishing microplastic particles from natural particles. This critical review provides an overview of the state-of-the-art procedures in microplastic analysis, gives examples of potential ways ahead and remaining challenges and classifies available methods according to the underlying research question. The resulting decision tree for the selection of analytical methods starts with a common research question and takes specificities of the environmental matrix into account. The procedural range consequently ranges from fast screening methods based on visual identification to a highly sophisticated combination of analytical methods that provide information on polymer type, particle number or mass and eventually particle size but are very time-consuming and expensive. Standardization of microplastic analytical methods on the basis of the research aim will help to make study results comparable and obtain a more comprehensive picture of microplastic abundance and fate in the environment.Zeng, F., Peng, F., Guo, J., Wang, D., Zhang, S., Zhang, P., Zhang, B., 2019. Gas transport study in the confined microfractures of coal reservoirs. Journal of Natural Gas Science and Engineering 68, 102920. are commonly observed in coal reservoirs. During the coalbed gas production process, stress sensitivity and coalbed gas viscosity changes are significant factors that affect gas transport. By using research methods based on desorption theory and elastic-plastic mechanics, a coal confined microfracture gas transport model that considers dynamic microfracture width variations and gas effective viscosity is established in this paper. This model comprehensively fuses the Knudsen diffusion model, the slip flow model, the surface diffusion model, and the cubic grid model. The reliability of this model is verified via molecular simulations, and the influence factors of gas transport capacity in confined microfractures of coal reservoirs are then discussed in detail. The results demonstrate the following findings. (1) The analyzed flows are well simulated in coal confined microfractures by the model established in this paper, which considers stress sensitivity and coalbed methane viscosity change. (2) Under low formation pressure (less than 5?MPa), the effective gas viscosity rapidly decreases with the decrease in formation pressure, and the negative contribution of gas viscosity change to the microfracture permeability of coal is large. The smaller the initial fracture width of coal, the more obvious this negative effect. (3) When the initial fracture width is fairly small (near 1?nm), Knudsen flow and surface diffusion greatly contribute to the microfracture permeability of coal. However, the larger the initial microfracture width, the smaller the contribution of the two flow regimes to the microfracture permeability, and the permeability is mainly provided by slip flow. (4) Under given conditions, the microfracture permeability of coal is positively related to rock mechanical parameters (Young's modulus and Poisson's ratio) and negatively related to fracture compressibility. Under low formation pressures (less than 15?MPa), the microfracture permeability of coal is positively related to gas desorption. When the formation pressure exceeds 15?MPa, the influence of gas desorption performance on permeability is nearly constant.Zeng, L., Huang, W., Jin, J., Ma, W., Yu, S., Pan, C., 2019. Vitrinite maturation in confined pyrolysis experiments. Energy & Fuels 7, 5981-5987. simulation (pyrolysis) is an important approach for the study of petroleum formation and evolution. It is useful to determine the maturity levels under experimental temperature and time conditions. Mean random vitrinite reflectance (%Ro) is a parameter widely used to demonstrate source rock maturity. Confined pyrolysis experiments were conducted for simulating vitrinite maturation on six coal samples with initial hydrogen indices (HI) ranging from 155 to 259 mg HC/g TOC at 2 and 20 °C/h heating rates. Coal JC24 having higher initial HI (259 mg HC/g TOC) has relatively lower measured vitrinite reflectance (%Ro) compared with that of coals JC23 and JC25 having lower initial HI (i.e., 171 and 155 mg HC/g TOC, respectively), at the same thermal stress levels. For all six coals, the measured %Ro is lower compared to the predicted EASY%Ro at >1.5 EASY%Ro. The differences between the measured %Ro and calculated EASY%Ro are substantially greater at 20 °C/h compared to 2 °C/h at the same thermal stress levels. These results demonstrate that the measured %Ro values are influenced by the hydrogen index and heating rate, in addition to temperature and heating time, and suggest that EASY%Ro values may be more representative of thermal stress compared with the measured %Ro for pyrolysis experiments in a wide range of EASY%Ro (0.50–4.40).Zhai, G., Li, J., Jiao, Y., Wang, Y., Liu, G., Xu, Q., Wang, C., Chen, R., Guo, X., 2019. Applications of chemostratigraphy in a characterization of shale gas Sedimentary Microfacies and predictions of sweet spots —taking the Cambrian black shales in Western Hubei as an example. Marine and Petroleum Geology 109, 547-560. research was conducted in this paper on the correlation of chemical elements with sedimentary microfacies and shale gas sweet spots through cluster analysis, factor analysis, and so on, using a large amount of geochemical data of elements obtained from shale gas exploration of the Cambrian Niutitang Formation in Western Hubei. This paper screened the chemical element associations and parameter systems that can reflect sedimentary microfacies and sweet spot evaluations, proposed a classification method for the chemostratigraphic facies of shales, and finely depicted the sedimentary chemical microfacies of the shales in the Cambrian Niutitang Formation. A chemostratigraphic lithofacies paleogeography map of SQ1 (the first sequence strata) in the Cambrian Niutitang Formation in Western Hubei was compiled. Sweet spots were predicted and evaluated, and favourable areas were predicted, thereby providing important support for making a breakthrough in the exploration of the Cambrian shale gas in the Yichang area. Chemostratigraphy has a higher precision and a low characterization cost of reservoir sedimentary microfacies; especially in areas lacking drilling data and seismic data and having a low exploration degree, chemostratigraphy is an important means for identifying of shale sedimentary sequences and predicting shale sweet spot sections.Zhai, G., Wang, Y., Liu, G., Zhou, Z., Bao, S., Chen, K., Kang, H., Zhang, J., Wang, S., Zhang, Y., 2019. The Sinian-Cambrian formation shale gas exploration and practice in southern margin of Huangling paleo-uplift. Marine and Petroleum Geology 109, 419-433. Sinian Doushantuo and the Cambrian Niutitang formations in southern China have a good shale gas resource potential. Although >20 wells have already been drilled in these formations, the shale gas production has been much lower than expected, due to the high thermal maturity of the rocks and the severely disturbed geological structure of the corresponding area. An industrial gas flow was discovered only in the Weiyuan region. To achieve the shale gas breakthrough of paleo-shale strata, it is necessary to find a shale reservoir with low thermal maturity and weak geological deformation. On the basis of the study on the Weiyuan, Huangling and other paleo-uplifts, a shale gas accumulation mechanism named “shale gas accumulating around the edges of paleo-uplifts” was proposed. It has been suggested that the shale gas is usually contained within the slope belt of a paleo-uplift margin characterized by a shallow burial depth, stable structure activity, and a low level of thermal maturity. Taking into account this accumulation mechanism, a large number of wells have been drilled on the southern edge of the Huangling paleo-uplift (western Hubei province). Organic-enriched shales with high shale gas content and low thermal maturity, have been found within the Sinian Doushantuo and the Cambrian Niutitang formations. To tackle the problems deriving from the low exploration level, complex geological structure, low temperature, and low pressure in the region, we proposed and applied innovative fracturing process, new complex fracturing techniques and new recovering technology systems. High and stable shale outputs were obtained from the Niutitang Formation (well Yangye-1HF, HF: Horizontal Well Fracturing) and from the Doushantuo Formation (well Yangye-2HF): 7.83?×?104 and 5.53?×?104?m3/day, respectively. These outputs were achieved following horizontal well section fracturing, which resulted in a significant breakthrough for the production capacity of the low-pressure shale gas reservoir in the complex tectonic region outside of the Sichuan Basin.Zhang, G., Gong, C., Gu, J., Katayama, Y., Someya, T., Gu, J.-D., 2019. Biochemical reactions and mechanisms involved in the biodeterioration of stone world cultural heritage under the tropical climate conditions. International Biodeterioration & Biodegradation 143, 104723. World Cultural Heritage stone monuments/temples suffer from severe deterioration from weathering caused by a combination of physical, chemical and biological forces. Current knowledge on biodeterioration of these stone monuments has been improving because of the suite of research techniques available. Previous investigations were mainly carried out with culture-dependent methods to isolate and describe a small number of microorganisms from selective sites. Now, the culture-independent method of Next Generation Sequencing technologies is readily available at an affordable cost to obtain a much more deeper information of the microbial community of many sites more quickly. Since flora, fauna and microorganisms are members of the complex community on stone monuments in tropical regions, the fundamental scientific question remains to be the biochemical mechanisms involved for the destruction to allow a better and fundamental understanding of the interactions between the inorganic materials and the colonizing biota. More importantly, the biochemical processes shall be given more attention under the local environmental conditions, especially the tropical climate. Organic acids and inorganic acids (sulfuric and nitric), produced by colonizing biota are known biochemical processes and mechanisms contributing to the attack of stone. Lichens, cyanobacteria, fungi and bacteria are ubiquitously detected on surfaces of stone monuments of Angkor, Maya and Inca. Sulfur cycle and the oxidation are known major contributing factor to the destruction of stone. Recently, ammonia-oxidizing archaea are found more abundant than ammonia-oxidizing bacteria on the Angkor monuments in Cambodia. In addition, the mobility of solutes into and out of the stone is also involved to the damage of sandstone under the influence of water regime and climate conditions. The available information on the specific biochemical mechanisms by the microbiota on stone provides important insights into the biochemical reactions involved and also the protective measures against biodeterioration of the world cultural heritage effectively.Zhang, G., Ranjith, P.G., Wu, B., Perera, M.S.A., Haque, A., Li, D., 2019. Synchrotron X-ray tomographic characterization of microstructural evolution in coal due to supercritical CO2 injection at in-situ conditions. Fuel 255, 115696. evolution in coal due to CO2 injection directly influences the gas transport and storage properties of coal during CO2 sequestration in deep coal seams. Using synchrotron X-ray tomography, we performed CT imaging under simulated reservoir conditions with a novel X-ray transparent core holder and investigated the time-dependent evolution of 3-D microstructures of an anthracite coal with 1.37% moisture as-received interacted with supercritical CO2 (ScCO2). Three sets of CT scans were taken: (1) coal was subjected to 10?MPa confining pressure before exposed to ScCO2, (2) coal was subjected to 10?MPa confining pressure and after 7?h of exposure to ScCO2, and (3) coal was subjected to 10?MPa confining pressure and after 53?h of exposure to ScCO2. When ScCO2 interacts with coal, complex physico-chemical reactions occur, changing coal microstructures in multiple ways and resulting in significant permeability changes. After 7?h ScCO2 injection, we directly observed the pre-existing microfracture closure, which was attributed to coal swelling. A significant permeability reduction was measured from 3.0 to 0.24??D with up to 26?h CO2 injection. With increasing injection duration, interestingly, we observed the wormhole growth in coal due to hydrocarbon mobilization and mineral dissolution, which accordingly caused a permeability rebound to 1.2??D after 53?h CO2 injection. Coal swelling occurred readily upon ScCO2 injection but hydrocarbon mobilization and mineral dissolution were delayed to affect the permeability probably due to the slower reaction kinetics. This study suggests that ScCO2 injection has the potential to improve the permeability and enhance the coalbed methane recovery due to the effects of hydrocarbon mobilization and mineral dissolution.Zhang, J., Zeng, Y., Slatt, R., 2019. XRF (X-ray fluorescence) applied to characterization of unconventional Woodford Shale (Devonian, U.S.A.) lateral well heterogeneity. Fuel 254, 115565. fluorescence (XRF) was applied to measuring drill cuttings in order to characterize reservoir heterogeneity along a horizontal wellbore that landed in the organic-rich Woodford Shale. The measured XRF data profile which is composed of different paleoenvironmental and sedimentary element proxies were interpreted along with microseismic data distribution patterns from hydraulic fracturing. Three representative microseismic event distribution patterns were selected as demonstrations for reservoir heterogeneity’s impact on hydraulic fracturing efficiency, reflected by the corresponding variation in the XRF profile. This case study indicates that heterogeneity is a non-negligible factor in unconventional shale reservoirs and controls the efficiency of hydraulic fracturing. XRF is not restricted to conduct vertical scale chemostratigraphic characterization on core and outcrop, but also applicable for lateral well heterogeneity characterization near wellbore, which helps optimizing hydraulic fracturing design and ultimately reducing the risk of production failure.Zhang, K., Jia, N., Liu, L., Li, S., 2019. Main and interactive effects of four factors on CO2 storage in fractured nanopores. Energy & Fuels 33, 6616-6627. this paper, main and interactive effects of four important factors, temperatures, adsorption thicknesses, fracture apertures, and feed CO2 concentrations, on the thermodynamic phase behavior for CO2 storage processes in the fractured nanopores of shale/tight reservoirs with adsorptions are investigated. First, a modified analytical equation of state is developed by considering the effects of confinements and intermolecular interactions, which is applied to predict the confined pure/mixing fluid phase behavior in fractured nanopores coupled with a novel empirical correlation for the adsorption thickness and the fracture geometry equation. Second, the aforementioned four important factors are studied to evaluate their main and interactive effects on the phase behavior of pure CO2, N2, O2, Ar, alkanes of C1–10, and their mixtures. It is found that all the pure and mixing fluid pressures monotonically and linearly increase to different extents with an increasing temperature. Moreover, the pressures/critical shifts and critical properties perform downward and upward parabola curves with respect to the adsorption thicknesses, respectively. On the other hand, the pressures/critical shifts are monotonically decreased, while the critical properties increase with the fracture apertures increasing from 0.01 up to 10 nm and remain constant afterward. By increasing the feed CO2 concentrations, the critical shifts and pressures for all of pure and mixing fluids are increased, while both the critical pressures and temperatures decrease. In addition, three interactive effects on the phase behavior are analyzed that the effect of a single factor behaves differently with the variations of any other factors. Finally, the amounts of the N2, O2, Ar, and light alkanes of C1–4 are suggested to be controlled for CO2 storage in the fractured nanopores because additions of these components strongly affect the mixture phase behavior.Zhang, L., Bai, G., Zhao, X., Zhou, L., Zhou, S., Jiang, W., Wang, Z., 2019. Oil-source correlation in the slope of the Qikou Depression in the Bohai Bay Basin with discriminant analysis. Marine and Petroleum Geology 109, 641-657. commonly-used tools for oil-source correlation, such as mass chromatograms of biomarkers and bivariate cross-plots of geochemical parameters, cannot deal with multiple geochemical parameters and plenty of samples simultaneously, leading to uncertainties in the results and even failures sometimes. In this paper, the discriminant analysis (DA) is selected from supervised machine learning algorithms, as it is superior to the commonly-used tools as well as other multivariate statistical methods, with the accumulation of geochemical data of source rocks and oils. In the slope of the Qikou Depression, the main source rocks in the third (Es3) and first members (Es1) of the Paleogene Shahejie Formation were deposited in similar depositional environments. The source rocks cannot be distinguished with the commonly-used tools. We firstly extended geochemical parameters and then used stepwise DA to select informative parameters and to develop a discriminant model for oil-source correlation. The 22 selected parameters are supported by geochemical characteristics of the source rocks in the study area. The DA of these parameters for oil-source correlation achieved a high correct rate of original validation (96.8%) and leave-one-out cross-validation (89.4%), indicating a sufficient discriminatory power. The oil-source correlation results with high posterior probabilities, showing strong similarity between the sources and oils, coincide with geological conditions and illustrate that there is still much exploration potential in the study area, especially for the Es3 petroleum system. All these illustrate that DA is one of the most useful tools for oil-source correlation with the accumulation of geochemical data of source rocks and oils.Zhang, L., Chen, Z., Li, Z., Zhang, S., Li, J., Liu, Q., Zhu, R., Zhang, J., Bao, Y., 2019. Structural features and genesis of microscopic pores in lacustrine shale in an oil window: A case study of the Dongying depression. American Association of Petroleum Geologists 103, 1889-1924. Paleogene shale of the Dongying depression, a continental basin in eastern China, is taken as the study subject to examine the microscopic features of lacustrine shale reservoirs in the oil window. This study shows that shale pores in this evolutionary stage are present at the micrometer to nanometer scale, but fractures commonly have extension distances at the millimeter scale. Pores and fractures can be divided into three types, namely, primary pores, secondary pores, and cracks. Primary pores commonly have good connectivity at shallow burial depth. With the increase of burial depth, primary porosity is reduced because of compaction and cementation. Secondary pores are important in shale, including dissolved pores inside grains and at grain edge, and dissolution pores inside the hybrid of organic matter (OM) and clay minerals, and evaporite minerals, including carbonates or sulfates. Types of cracks were observed: bedding fissures, dissolution fractures, and structural fractures. The development of bedding fissures is related to the deposition of shale laminae. The formation of dissolution fractures is related to acidic fluids, such as organic acids and hydrogen sulfide, whereas the formation of structural fractures is jointly controlled by fault development, fluid overpressure, and lithofacies. The pores and fractures in the oil window of lacustrine shale can store and channel oil and gas. The hybrid OM–clay–carbonate (sulfate) and the pores inside are important through the oil window. Moreover, the development of the pores depends not only on hydrocarbon generation but also on the interaction of hydrocarbons and organic acid dissolution. This finding has important significance in the accumulation of oil and gas in continental shales.Zhang, W., Wirtz, K., Daewel, U., Wrede, A., Kr?ncke, I., Kuhn, G., Neumann, A., Meyer, J., Ma, M., Schrum, C., 2019. The budget of macrobenthic reworked organic carbon: A modeling case study of the North Sea. Journal of Geophysical Research: Biogeosciences 124, 1446-1471. importance of macrobenthos in benthic-pelagic coupling and early diagenesis of organic carbon has long been recognized but has not been quantified at a regional scale. By using the southern North Sea as an exemplary area we present a modeling attempt to quantify the budget of total organic carbon (TOC) reworked by macrobenthos in seafloor surface sediments. Vertical profiles in sediments collected in the field indicate a significant but nonlinear correlation between TOC and macrobenthic biomass. A mechanistic model is used to resolve the bidirectional interaction between TOC and macrobenthos. A novelty of this model is that bioturbation is resolved dynamically depending on variations in local food resource and macrobenthic biomass. The model is coupled to 3-D hydrodynamic-biogeochemical simulations to hindcast the mutual dependence between sedimentary TOC and macrobenthos from 1948 to 2015. Agreement with field data reveals a satisfactory model performance. Our simulations show that the preservation of TOC in the North Sea sediments is determined not only by pelagic conditions (hydrodynamic regime and primary production) but also by the vertical distribution of TOC, bioturbation intensity, and the vertical positioning of macrobenthos. Macrobenthos annually ingest 20?35% and in addition vertically diffuse 11?22% of the total budget of TOC in the uppermost 30-cm sediments in the southern North Sea. This result indicates a central role of benthic animals in modulating the organic carbon cycling at the sediment-water interface of continental margins.Zhang, Y.-M., Zhang, Y.-Y., Zhang, Q., Lv, Y., Sun, T., Han, L., Bai, C.-C., Yu, Y.-J., 2019. Automatic peak detection coupled with multivariate curve resolution–alternating least squares for peak resolution in gas chromatography–mass spectrometry. Journal of Chromatography A 1601, 300-309.–Gas chromatography–mass spectrometry (GCMS) has been extensively used in complex sample analysis for the high-throughput characterization of volatile and semivolatile compounds. However, the accurate extraction of compound information remains challenging. Here, we present a combined algorithm strategy for GC–MS data analysis to accurately screen metabolites across groups. First, chromatographic peaks in a total ion chromatogram (TIC) are extracted by using a Gaussian smoothing strategy and aligned on the basis of their mass spectra by a dynamic programing algorithm. The aligned TIC peaks are then registered into a component list table by applying a nearest-neighbor clustering algorithm. Significantly expressed TIC peaks among groups are screened through statistical analysis, such as ANOVA. Second, a chemometric method of multivariate curve resolution–alternating least squares for the peak resolution of the screened TIC peaks is utilized to retrieve the chromatographic and mass spectral profiles of coeluted components. The developed strategy is employed for the analysis of standard and complex plant sample datasets. Results indicate that our methodology is comparable with several state-of-the-art methods that are widely used in GC–MS-based metabolomics.Zhang, Y., Schulz, F., Rytting, B.M., Walters, C.C., Kaiser, K., Metz, J.N., Harper, M.R., Merchant, S.S., Mennito, A.S., Qian, K., Kushnerick, J.D., Kilpatrick, P.K., Gross, L., 2019. Elucidating the geometric substitution of petroporphyrins by spectroscopic analysis and atomic force microscopy molecular imaging. Energy & Fuels 33, 6088-6097. of the molecular structures of petroporphyrins has been crucial to understand the diagenetic pathways and maturation of petroleum. However, these studies have been hampered by their structural complexity and the challenges associated with their isolation. In comparison to the skeletal macrocyclic structures, much less is known about the substitutions, which are more sensitive to the maturation and diagenesis pathways. While these isolated vanadyl petroporphyrins largely consist of etioporphyrin and deoxophylloerythroetioporphyrin as expected, surprisingly, we find evidence that one or a few β hydrogens are present in petroporphyrins of low carbon numbers using a combination of ultraviolet–visible spectroscopy, Fourier transform ion cyclotron resonance mass spectrometry, and non-contact atomic force microscopy. Petroporphyrins with β hydrogens were not anticipated on the basis of their biological precursors. The data support dealkylation under catagenesis but not transalkylation or random alkylation of the β and meso positions, despite the fact that more complex porphyrin structures are formed.Zhang, Y.G., Pearson, A., Benthien, A., Dong, L., Huybers, P., Liu, X., Pagani, M., 2019. Refining the alkenone-pCO2 method I: Lessons from the Quaternary glacial cycles. Geochimica et Cosmochimica Acta 260, 177-191. alkenone-pCO2 method is one of the most widely used approaches to reconstruct atmospheric CO2 in the Cenozoic. The method depends upon fractionation of stable carbon isotopes during algal photosynthesis, expressed as εp37:2, and a physiological scaling parameter, b, that accounts for biological factors such as growth rate, cell size, and membrane permeability. Alkenone-derived CO2 records for the late Pleistocene, however, are poorly correlated with ice core CO2, challenging the classic model that considers most of the CO2 used for coccolithophore photosynthesis to be acquired through simple diffusion. In this study, we investigate the nature of the b term and the underlying patterns of the sensitivity of εp37:2 to pCO2 changes. We generated two new εp37:2 records from the South China Sea (MD01-2392) and tropical Atlantic Ocean (ODP 668B) and compiled other published εp37:2 records over glacial-interglacial cycles. Using the εp37:2 data, ocean temperature estimates, and ice core CO2, we were able to back-calculate the corresponding values of b. At all locations, b varies over glacial cycles. The highest values of b correspond to peak interglacial stages, indicating that the phytoplankton growth rate is faster or cell size is smaller during interglacials than during glacial periods. We further show that the range of εp37:2 between glacial and interglacial conditions, Δεp37:2, scales with growth conditions, consistent with the predictions of the carbon isotope fractionation model based on CO2 diffusion. In other words, the sensitivity of εp37:2 to pCO2 changes increases where the modern b values are large, contradicting the recommendations that oligotrophic sites are the best for alkenone-CO2 applications because of the presumed stability of b. Using the average back-calculated b value for each site, the composite pCO2 estimates from MD01-2392 and ODP 668B – the two sites with adequate Δεp37:2 sensitivity – show broad agreement with the ice core CO2 record.Zhao, B., MacMinn, C.W., Primkulov, B.K., Chen, Y., Valocchi, A.J., Zhao, J., Kang, Q., Bruning, K., McClure, J.E., Miller, C.T., Fakhari, A., Bolster, D., Hiller, T., Brinkmann, M., Cueto-Felgueroso, L., Cogswell, D.A., Verma, R., Prodanovi?, M., Maes, J., Geiger, S., Vassvik, M., Hansen, A., Segre, E., Holtzman, R., Yang, Z., Yuan, C., Chareyre, B., Juanes, R., 2019. Comprehensive comparison of pore-scale models for multiphase flow in porous media. Proceedings of the National Academy of Sciences 116, 13799-13806.: The simultaneous flow of multiple fluid phases through a porous solid occurs in many natural and industrial processes. Microscale physical mechanisms such as the relative affinity of the solid for the fluids (i.e., wettability), capillarity, and viscosity combine with pore geometry to produce a wide variety of macroscopic flow patterns. Pore-scale modeling is an essential tool to connect microscale mechanisms with macroscopic patterns, but quantitative comparisons between different models, and with experimental data, are lacking. Here, we perform an unprecedented comparison of state-of-the-art models from 14 leading groups with a recent experimental dataset. The results underscore the challenges of simulating multiphase flows through porous media, highlighting specific areas for further effort in what is already a flourishing field of research.Abstract: Multiphase flows in porous media are important in many natural and industrial processes. Pore-scale models for multiphase flows have seen rapid development in recent years and are becoming increasingly useful as predictive tools in both academic and industrial applications. However, quantitative comparisons between different pore-scale models, and between these models and experimental data, are lacking. Here, we perform an objective comparison of a variety of state-of-the-art pore-scale models, including lattice Boltzmann, stochastic rotation dynamics, volume-of-fluid, level-set, phase-field, and pore-network models. As the basis for this comparison, we use a dataset from recent microfluidic experiments with precisely controlled pore geometry and wettability conditions, which offers an unprecedented benchmarking opportunity. We compare the results of the 14 participating teams both qualitatively and quantitatively using several standard metrics, such as fractal dimension, finger width, and displacement efficiency. We find that no single method excels across all conditions and that thin films and corner flow present substantial modeling and computational challenges.Zhao, D., Guo, Y., Wang, G., Mao, X., 2019. Characterizing nanoscale pores and its structure in coal: Experimental investigation. Energy Exploration & Exploitation 37, 1320-1347. of the challenges in evaluating and estimating the gas storage and migration of coal has been the investigation of complex pore structures, especially in the nanoscale. The present study provides new insights into nanoscale pore types, and the genesis, classification, and structure characteristics of high-rank coal by investigating 10 anthracite coals in the Shanxi Formation and Taiyuan Formation of the Xinjing Coal Mine in the Qinshui Basin, North China. A series of experiments that combined the qualitative observation method of argon ion polishing technology in combination with field emission-scanning electron microscope and quantitative analysis methods of low-pressure N2 gas adsorption and mercury intrusion porosimetry were performed to characterize nanoscale pore structures and its influence on gas behavior. The results revealed that various types of nanoscale pores exist in the coal matrix. Descriptive classifications for nanoscale pores consist of three major groups (organic matter pores, mineral-related pores, and micro-fractures), and nine subtypes was summarized to correlate pores to the networks. Furthermore, mercury intrusion porosimetry, low-pressure N2 gas adsorption, and image processing were combined to determine the pore size distributions, indicating that pore sizes are bimodally distributed with two broad peaks. The major peak at approximately 20–400 nm was mostly associated with isolated microscopic organic constituents interparticle nanopores, while a minor but prominent peak at the macro-pore to micro-fracture scale was more associated with epigenetic pores, mineral-related pores, and micro-fractures. Furthermore, image processing also provides a specialized approach to reveal the structure and diameter of different types of nanoscale pores. The combination of quantitative test and qualitative observation indicate that different major pore types dominate each size range of reservoir space in coal. These results lead to a feasible assumption that the poor connectivity of nanoscale pores and lack of seepage channels between the nanoscale pores and fracture-cleat networks may have led to the low “micro-permeability” of the coal matrix, which affects the productivity of coalbed methane in high-rank coal.Zhao, J., Wang, P., Yu, X., Shu, W., Xu, Q., 2019. Structure and composition of sediment-associated bacterial and eukaryotic communities in the river–lake system of Poyang Lake, China. Geomicrobiology Journal 36, 727-736. play key ecological roles in aquatic and terrestrial environments. However, little is known of the differences in physicochemical and geographical factors influencing the bacterial and eukaryotic communities and of the relative contribution of these two types of predictors in such systems. Here, we investigated the structure and influential factors on bacterial and eukaryotic communities within the river?lake ecosystem sediments using high-throughput DNA sequencing. Numerous physicochemical parameters and geographical locations were measured among 15 sampling sites in the river?lake system of Poyang Lake. Bacterial communities were dominated by Proteobacteria (32.08%), Acidobacteria (16.58%), and Chloroflexi (14.39%), while eukaryotic communities were dominated by Fungi (63.32%) and Alveolata (10.2%). Both bacterial and eukaryotic community structures statistically correlated with C, N, and Fe, but only bacterial community structure significantly correlated with pH, ON, and Fe. Variation partitioning analysis revealed that physicochemical parameters controlled strongly both bacterial and eukaryotic communities, whereas the direct influence of geographical coordinates and a combination of physicochemical parameters and geographical coordinates controlled relatively small. Bacterial community (31.64%) exhibited a stronger influence by physicochemical parameters than the eukaryotic community (17%).Zhao, L., Li, Y., Zhang, L., Zheng, J., Pierce, E.M., Gu, B., 2019. Mercury adsorption on minerals and its effect on microbial methylation. ACS Earth and Space Chemistry 3, 1338-1345. or solid-phase inorganic mercury [Hg(II)] is commonly assumed immobile or less bioavailable for microbial uptake, although recent studies suggest that mineral-adsorbed Hg(II) is at least partially available for cell uptake and methylation. This study examined the adsorption of Hg(II) onto two reference minerals, hematite and montmorillonite, and evaluated Hg(II) uptake and methylation by a sulfate-reducing bacterium Desulfovibrio desulfuricans ND132 in laboratory incubations. Mineral-adsorbed Hg(II) on both hematite and montmorillonite was not only available for cell uptake and methylation but also resulted in a 2–3-fold increased methylmercury production compared to the mineral-free incubation. An optimal Hg(II) methylation was observed at a low to moderate mineral/solution ratio (1–5 g L–1) with fixed Hg(II) (25 nM) and cell concentrations. The result could be explained by decreased cellular immobilization of Hg(II) but enhanced close interactions between Hg(II) and cells both adsorbed or concentrated on mineral surfaces, leading to increased methylation. However, a high mineral/solution ratio inhibited Hg(II) methylation, likely as a result of a low Hg(II) coverage (per surface area) at high mineral loadings, which limit close contacts between Hg(II) and the cells. These results indicate that mineral-adsorbed Hg(II) may be directly available for microbial uptake or methylation, although whether the adsorption enhances or inhibits Hg(II) methylation may depend upon microniches, where Hg(II), microbes, and minerals co-exist in the natural environment. We suggest that future studies are performed to establish quantitative relationships of bioavailable Hg(II) with not only the dissolved but also adsorbed Hg(II) species to improve model predictions of Hg(II) fate and transformations.Zhao, L., Shirai, K., Murakami-Sugihara, N., Higuchi, T., Tanaka, K., 2019. Mussel periostracum as a high-resolution archive of soft tissue δ13C records in coastal ecosystems. Geochimica et Cosmochimica Acta 260, 232-243. carbon isotope ratios (δ13C) of mussel soft tissues have been widely used to characterize baseline δ13C isoscapes and identify carbon sources at the base of coastal food webs. Extending soft tissue δ13C records back in time, however, is extremely challenging due to very limited sample availability. Here, we test if the stable carbon isotopic composition of periostracum (the outermost organic layer of the shell) in the Mediterranean mussel (Mytilus galloprovincialis) can be used as an environmental archive, similar to soft tissue records. In general, spatial and seasonal variations of periostracum δ13C values are comparable to those of soft tissues, but apparently the latter are more time-averaged and smoothed. Irrespective of such offset, there is a significant linear correlation between mussel periostracum and soft tissue δ13C values (R2?=?0.608, p?<?0.001). Moreover, high-resolution δ13C analysis of mussel periostracum indicates that it integrates much less time than soft tissue due to metabolically inert nature, consequently being able to record predictable events such as tidal changes and also unpredictable ephemeral events in coastal ecosystems. The present study demonstrates the potential of the periostracum as a viable alternative to the most widely used soft tissues in isotopic studies. Most promisingly, given ample collections over time scales up to hundreds of years and usually stored dry, this technique could be used to extend coastal organic carbon δ13C records back in time.Zheng, Q., Chen, Q., Cai, R., He, C., Guo, W., Wang, Y., Shi, Q., Chen, C., Jiao, N., 2019. Molecular characteristics of microbially mediated transformations of Synechococcus-derived dissolved organic matter as revealed by incubation experiments. Environmental Microbiology 21, 2533-2543. this study, we investigated the microbially mediated transformation of labile Synechococcus‐derived DOM to RDOM using a 60‐day experimental incubation system. Three phases of TOC degradation activity (I, II and III) were observed following the addition of Synechococcus‐derived DOM. The phases were characterized by organic carbon consumption rates of 8.77, 1.26 and 0.16?μmol?L?1 day?1, respectively. Excitation emission matrix analysis revealed the presence of three FDOM components including tyrosine‐like, fulvic acid‐like, and humic‐like molecules. The three components also exhibited differing biological availabilities that could be considered as labile DOM (LDOM), semi‐labile DOM (SLDOM) and RDOM, respectively. DOM molecular composition was also evaluated using FT‐ICR MS. Based on differing biological turnover rates and normalized intensity values, a total of 1704 formulas were identified as candidate LDOM, SLDOM and RDOM molecules. Microbial transformation of LDOM to RDOM tended to proceed from high to low molecular weight, as well as from molecules with high to low double bond equivalent (DBE) values. Relatively higher aromaticity was observed in the formulas of RDOM molecules relative to those of LDOM molecules. FDOM components provide valuable proxy information to investigate variation in the bioavailability of DOM. These results suggest that coordinating fluorescence spectroscopy and FT‐ICR MS of DOM, as conducted here, is an effective strategy to identify and characterize LDOM, SLDOM and RDOM molecules in incubation experiments emulating natural systems. The results described here provide greater insight into the metabolism of phytoplankton photosynthate by heterotrophic bacteria in marine environments.Zhou, C., Wu, H., Zhang, X., Zhang, Y., Xie, W., Xu, W., 2019. High-throughput and direct sample screening using a laser spray ionization miniature mass spectrometer. Analytical Chemistry 91, 8808-8813. the past two decades, great efforts have been made toward mass spectrometer instrument miniaturization. With increasing analytical performances, miniature mass spectrometers are on the edge of being applied to more application scenarios. Besides sensitivity, mass resolution, and instrument portability, high-throughput and little or no sample preparation are also critical features in practical applications. In this study, we report the development of a miniature mass spectrometry (MS) system equipped with a 2D moving platform and a laser spray ionization (LSI) source. The method to make a patterned sample holder was also introduced and optimized for automatic high-throughput sample analyses. With the LSI source, analytes in complex matrix could be directly mass analyzed; in addition to the 2D moving platform, different samples could be analyzed in a high-throughput fashion. Results show that good linearity of quantitation could be achieved for multiple samples. Tens of nanograms of drugs, peptides, and vitamin B could be identified in diluted whole blood samples, and it takes 10 s on average to scan one sample.Zhou, L., Zhou, Z., Lu, Y.-W., Ma, L., Bai, Y., Li, X.-X., Mbadinga, S.M., Liu, Y.-F., Yao, X.-C., Qiao, Y.-J., Zhang, Z.-R., Liu, J.-F., Yang, S.-Z., Wang, W.-D., Gu, J.-D., Mu, B.-Z., 2019. The newly proposed TACK and DPANN archaea detected in the production waters from a high-temperature petroleum reservoir. International Biodeterioration & Biodegradation 143, 104729. the diversity and distribution of archaea is basically crucial to understanding their ecological functions in subsurface petroleum reservoir ecosystems. However, the knowledge about the abundance and distribution of newly proposed archaea (e.g. TACK and DPANN superphyla) in such environments is still limited. In the present work, archaeal communities from five production wells of a high-temperature petroleum reservoir were characterized by high-throughput sequencing. The outcome showed that in the five samples over 98% of archaeal sequences were affiliated to Euryarchaeota, and the rest belonged to newly proposed archaeal phyla (Thaumarchaeota, Verstraetearchaeota, Bathyarchaeota, Aigarchaeota and Woesearchaeota). Based on the defined criteria of rare taxa (<0.1%), OTUs affiliated within Bathyarchaeota, Thaumarchaeota and Woesearchaeota were mostly present as the rare biosphere in the samples. The archaeal communities were significantly shaped by different geochemical parameters of the production waters from the petroleum reservoir. The co-occurrence network analysis revealed the potential syntrophic interactions among the archaea themselves in the subterrestrial environments. Our results indicate that the newly proposed archaea are ubiquitous, also present in the petroleum reservoirs, where they contribute to the ecosystem diversity and play potential roles in the biogeochemical cycle of carbon. This work also provides an overall understanding of the identity, ecology, and functional diversity of newly proposed archaea in petroleum reservoirs.Zhou, W., Wang, H., Yan, Y., Liu, X., 2019. Adsorption mechanism of CO2/CH4 in kaolinite clay: Insight from molecular simulation. Energy & Fuels 33, 6542-6551. the adsorption mechanism of CO2/CH4 in kaolinite clay is essential for the carbon dioxide geological sequestration and enhanced gas recovery in shale reservoirs. In the present work, grand canonical Monte Carlo simulations were employed to investigate the mechanism of competitive adsorption of CO2/CH4 in kaolinite clay. The effects of pore size (1–6 nm), pressure (0.1–30 MPa), temperature (298–378 K), and moisture content (0–0.122 g/cm3) on the adsorption behaviors of pure CH4 and CO2/CH4 mixture were explored in-depth. Specifically, two adsorption layers, i.e., strong and weak adsorption layers, in kaolinite slitlike micropore under high pressure condition have been observed. It was found that pore size and pressure have great effects on the gas adsorption mechanism in kaolinite. The two adsorption mechanisms including monolayer adsorption and micropore filling under high pressure or small pore size conditions were discussed. In addition, simulation results showed that CO2 has much stronger adsorption ability than CH4 in kaolinite. The adsorption capacity of CH4 was significantly suppressed in the presence of CO2, especially in the strong adsorption layer. An adsorption selectivity over 7 has been found in the strong adsorption layer. Temperature and moisture content have great influences on the adsorption capacity and adsorption selectivity. However, the influences have different scales in strong and weak adsorption layers. It is expected the obtained results could provide insights into the adsorption mechanism of CO2/CH4 and offer fundamental data for a CO2 sequestration and enhanced gas recovery (CS-EGR) project in kaolinite clay.Zhou, Y., Martin, P., Müller, M., 2019. Composition and cycling of dissolved organic matter from tropical peatlands of coastal Sarawak, Borneo, revealed by fluorescence spectroscopy and parallel factor analysis. Biogeosciences 16, 2733-2749. Asian peatlands supply ～10?% of the global flux of dissolved organic carbon (DOC) from land to the ocean, but the biogeochemical cycling of this peat-derived DOC in coastal environments is still poorly understood. Here, we use fluorescence spectroscopy and parallel factor (PARAFAC) analysis to distinguish different fractions of dissolved organic matter (DOM) in peat-draining rivers, estuaries and coastal waters of Sarawak, Borneo. The terrigenous fractions showed high concentrations at freshwater stations within the rivers, and conservative mixing with seawater across the estuaries. The autochthonous DOM fraction, in contrast, showed low concentrations throughout our study area at all salinities. The DOM pool was also characterized by a high degree of humification in all rivers and estuaries up to salinities of 25. These results indicate a predominantly terrestrial origin of the riverine DOM pool. Only at salinities >?25 did we observe an increase in the proportion of autochthonous relative to terrestrial DOM. Natural sunlight exposure experiments with river water and seawater showed high photolability of the terrigenous DOM fractions, suggesting that photodegradation may account for the observed changes in the DOM composition in coastal waters. Nevertheless, based on our fluorescence data, we estimate that at least 20?%–25?% of the DOC at even our most marine stations (salinity?>?31) was terrestrial in origin, indicating that peatlands likely play an important role in the carbon biogeochemistry of Southeast Asian shelf seas.Zhu, B., Ge, L., Yang, T., Jiang, S., Lv, X., 2019. Stable isotopes and rare earth element compositions of ancient cold seep carbonates from Enza River, northern Apennines (Italy): Implications for fluids sources and carbonate chimney growth. Marine and Petroleum Geology 109, 434-448. seep carbonates are remarkable fossil records of hydrocarbon seepage and related conduits. In the present research, we analysed the carbon and oxygen isotopes, rare earth element (REE) and trace element content of carbonate chimneys and concretions in the Pleistocene Argille Azzurre Formation, northern Apennines, Italy. Strong 13C depletions (values as low as ?40.3‰) observed in both carbonate concretions and chimneys indicate that anaerobic oxidation of biogenic methane played a major role in the formation of these carbonates. Slightly higher δ13C values mostly found in the outer layers of the carbonate chimneys reflect a contribution of inorganic carbon from seawater. REE patterns reveal the carbonates formed under mostly anoxic pore water conditions. Combined REE and trace element data reveal the growth of chimneys occurred from the outside-in, with the outer chimney walls experiencing rapid growth. Excellent correlations between Ce/Ce*, REE contents, and LaN/SmN and Y/Ho ratios observed in the chimney walls provide additional evidence for the influence of seawater in the formation of the chimneys. Meanwhile, O isotopic compositions of the samples suggest an 18O-depleted fluid was involved in carbonate precipitation. This study has major implications for tracking fluid sources of seep carbonates and patterns of carbonate chimney growth.Zhu, M.-H., Artemieva, N., Morbidelli, A., Yin, Q.-Z., Becker, H., Wünnemann, K., 2019. Reconstructing the late-accretion history of the Moon. Nature 571, 226-229. importance of highly siderophile elements (HSEs; namely, gold, iridium, osmium, palladium, platinum, rhenium, rhodium and ruthenium) in tracking the late accretion stages of planetary formation has long been recognized. However, the precise nature of the Moon’s accretional history remains enigmatic. There is a substantial mismatch in the HSE budgets of?the Earth and the Moon, with the?Earth seeming to have accreted disproportionally more HSEs than the Moon. Several scenarios have been proposed to explain this conundrum, including the delivery of HSEs to the?Earth by a few big impactors1, the accretion of pebble-sized objects on dynamically cold orbits that enhanced the Earth’s gravitational focusing factor, and the ‘sawtooth’ impact model, with its much reduced impact flux before about 4.10 billion years ago. However, most of these models assume a high impactor-retention ratio (the fraction of impactor mass retained on the target) for the Moon. Here we perform a series of impact simulations to quantify the impactor-retention ratio, followed by a Monte Carlo procedure considering a monotonically decaying impact flux, to compute the impactor mass accreted into the lunar crust and mantle over their histories. We find that the average impactor-retention ratio for the Moon’s entire impact history is about three times lower than previously estimated. Our results indicate that, to match the HSE budgets of the lunar crust and mantle, the retention of HSEs should have started 4.35 billion years ago, when most of the lunar magma ocean was solidified. Mass accreted before this time must have lost its HSEs to the lunar core, presumably during lunar mantle crystallization9. The combination of a low impactor-retention ratio and a late retention of HSEs in the lunar mantle provides a realistic explanation for the apparent deficit of the Moon’s late-accreted mass relative to that of the?Earth.Ziegler, G., Gonsior, M., Fisher, D.J., Schmitt-Kopplin, P., Tamburri, M.N., 2019. Formation of brominated organic compounds and molecular transformations in dissolved organic matter (DOM) after ballast water treatment with sodium dichloroisocyanurate dihydrate (DICD). Environmental Science & Technology 53, 8235-8243. water treated with a ballast water management system (BWMS) using a solution of dissolved dichloroisocyanurate dihydrate (DICD) resulted in the formation of newly described brominated disinfection byproducts (Br-DBPs). Analysis of dissolved organic matter (DOM) in untreated water with ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) identified 3897 m/z ions and their exact molecular formulas. After DICD treatment, a total of 213 halogenated molecular ions with relative abundance of at least 1% were assigned and confirmed using isotope simulation. Halogenated ions were assigned in four DBP elemental groups including CHOBr (180), CHONBr (13), CHOCl (16), and CHOBrCl (4). Forty-nine of the 197 brominated formulas have not been previously reported. We also were able to tentatively assign possible structures to the formula C3HBr3N2 due to very limited isomeric possibilities. The tentatively assigned compound found at 6.4% relative abundance was identified as either tribromoimidazole or tribromopyrazole. Our results show the formation of complex halogenated DBPs that are formed in the treatment of water with a novel BWMS that employs granular DICD as a biocide. The toxicological and mutagenic properties as well as the fate of these newly identified brominated DBPs are unknown.Zito, P., Podgorski, D.C., Johnson, J., Chen, H., Rodgers, R.P., Guillemette, F., Kellerman, A.M., Spencer, R.G.M., Tarr, M.A., 2019. Molecular-level composition and acute toxicity of photosolubilized petrogenic carbon. Environmental Science & Technology 53, 8235-8243. examine the molecular-level composition and acute toxicity per unit carbon of the petroleum-derived dissolved organic matter (DOMHC) produced via photo-oxidation, heavy and light oils were irradiated over seawater with simulated sunlight. Increases in dissolved organic carbon concentrations as a function of time were associated with changes in the DOMHC composition and acute toxicity per unit carbon. Parallel factor analysis showed that the fluorescent dissolved organic matter (FDOM) composition produced from the heavy oil became more blue-shifted over time, while the light oil produced a mixture of blue- and red-shifted components similar to FDOM signatures. Ultrahigh-resolution mass spectrometry reveals that the composition of the DOMHC produced from both heavy and light oils was initially relatively reduced, with low O/C. With time, the composition of the DOMHC produced from the heavy oil shifted to unsaturated, high-oxygen compounds, while that produced from the light oil comprised a range of high O/C aliphatic, unsaturated, and aromatic compounds. Microtox assays suggest that the DOMHC initially produced is the most toxic (62% inhibition); however, after 24 h, a rapid decrease in toxicity decreased linearly to 0% inhibition for the heavy DOMHC and 12% inhibition for the light DOMHC at extended exposure periods.Zoccali, M., Tranchida, P.Q., Mondello, L., 2019. Fast gas chromatography-mass spectrometry: A review of the last decade. TrAC Trends in Analytical Chemistry 118, 444-452. present contribution is an overview of the state-of-the-art of fast gas chromatography coupled to mass spectrometry (fast GC-MS). Specifically, published papers over the last ten years (2009–December 2018) have been considered. Several aspects of fast GC-MS are here critically discussed, focusing on four of the most common routes to shorten GC analyses times: micro-bore columns, narrow-bore columns, low-pressure outlet conditions, and resistive heating. Moreover, great attention has been dedicated to mass spectrometry coupling. Finally, the strong and weak points of each high-speed GC approach are also highlighted.Zouari, O., Lecouturier, D., Rochex, A., Chataigne, G., Dhulster, P., Jacques, P., Ghribi, D., 2019. Bio-emulsifying and biodegradation activities of syringafactin producing Pseudomonas spp. strains isolated from oil contaminated soils. Biodegradation 30, 259-272. strains isolated from oil contaminated soils were screened for biosurfactant production. Three out of eleven Pseudomonas isolates were selected for their high emulsifying activity (E24 value on n-hexadecane?~?78%). These isolates (E39, E311 and E313) were identified as members of the P. putida group using phenotypical methods and a molecular approach. To identify the chemical nature of produced biosurfactants, thin layer chromatography and MALDI-ToF mass spectrometry analysis were carried out and revealed lipopeptides belonging to the syringafactin family. The activity of the produced biosurfactants was stable over a pH range of 6–12, at high salinity (10%) and after heating at 80?°C. Tests in contaminated sand micro-bioreactors showed that the three strains were able to degrade diesel. These results suggest the potential of these syringafactin producing strains for application in hydrocarbon bioremediation. ................
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