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GEOCHEMISTRY ARTICLES – January 2020?Analytical ChemistryAparecida Silva Almeida, C., Regina Baggio, S., Regina Barros Mariutti, L., Bragagnolo, N., 2020. One-step rapid extraction of phytosterols from vegetable oils. Food Research International 130, 108891.Bastviken, D., Nygren, J., Schenk, J., Parellada Massana, R., Duc, N.T., 2020. Technical note: Facilitating the use of low-cost methane (CH4) sensors in flux chambers – calibration, data processing, and an open source make-it-yourself logger. Biogeosciences Discussions 2020, 1-16.Bian, X., Wang, K., Tan, E., Diwu, P., Zhang, F., Guo, Y., 2020. A selective ensemble preprocessing strategy for near-infrared spectral quantitative analysis of complex samples. Chemometrics and Intelligent Laboratory Systems 197, 103916.Bolotnik, T.A., Timchenko, Y.V., Plyushchenko, I.V., Levkina, V.V., Pirogov, A.V., Smolenkov, A.D., Popik, M.V., Shpigun, O.A., 2019. Use of chemometric methods of data analysis for the identification and typification of petroleum and petroleum products. Journal of Analytical Chemistry 74, 1336-1340.Culka, A., Ko?ek, F., Oren, A., Mana, L., Jehli?ka, J., 2019. Detection of carotenoids of halophilic prokaryotes in solid inclusions inside laboratory-grown chloride and sulfate crystals using a portable Raman spectrometer: applications for Mars exploration. FEMS Microbiology Letters 366, fnz239.Elsayed, M., Mahmoud, M., El-Husseiny, A., Kamal, M.S., Al-Garadi, K., 2019. A new method to evaluate reaction kinetics of acids with carbonate rocks using NMR diffusion measurements. Energy & Fuels 34, 787-797.Fan, M., Andrade, G.F.S., Brolo, A.G., 2020. A review on recent advances in the applications of surface-enhanced Raman scattering in analytical chemistry. Analytica Chimica Acta 1097, 1-29.Hansen, F.A., Pedersen-Bjergaard, S., 2020. Emerging extraction strategies in analytical chemistry. Analytical Chemistry 92, 2-15.Langer, J., Jimenez de Aberasturi, D., Aizpurua, J., Alvarez-Puebla, R.A., Auguié, B., Baumberg, J.J., Bazan, G.C., Bell, S.E.J., Boisen, A., Brolo, A.G., Choo, J., Cialla-May, D., Deckert, V., Fabris, L., Faulds, K., García de Abajo, F.J., Goodacre, R., Graham, D., Haes, A.J., Haynes, C.L., Huck, C., Itoh, T., K?ll, M., Kneipp, J., Kotov, N.A., Kuang, H., Le Ru, E.C., Lee, H.K., Li, J.-F., Ling, X.Y., Maier, S.A., Mayerh?fer, T., Moskovits, M., Murakoshi, K., Nam, J.-M., Nie, S., Ozaki, Y., Pastoriza-Santos, I., Perez-Juste, J., Popp, J., Pucci, A., Reich, S., Ren, B., Schatz, G.C., Shegai, T., Schlücker, S., Tay, L.-L., Thomas, K.G., Tian, Z.-Q., Van Duyne, R.P., Vo-Dinh, T., Wang, Y., Willets, K.A., Xu, C., Xu, H., Xu, Y., Yamamoto, Y.S., Zhao, B., Liz-Marzán, L.M., 2020. Present and future of surface-enhanced Raman scattering. ACS Nano 14, 28-117.Moro, M.K., Neto, ?.C., Lacerda, V., Rom?o, W., Chinelatto, L.S., Castro, E.V.R., Filgueiras, P.R., 2020. FTIR, 1H and 13C NMR data fusion to predict crude oils properties. Fuel 263, 116721.Pichon, V., Delaunay, N., Combès, A., 2020. Sample preparation using molecularly imprinted polymers. Analytical Chemistry 92, 16-33.Richardson, S.D., Kimura, S.Y., 2020. Water analysis: Emerging contaminants and current issues. Analytical Chemistry 92, 473-505.Sakamoto, T., Qiu, Z., Inagaki, M., Fujimoto, K., 2020. Simultaneous amino acid analysis based on 19F NMR using a modified OPA-derivatization method. Analytical Chemistry 92, 1669-1673.Xia, L., Yang, J., Su, R., Zhou, W., Zhang, Y., Zhong, Y., Huang, S., Chen, Y., Li, G., 2020. Recent progress in fast sample preparation techniques. Analytical Chemistry 92, 34-48.Xu, L., Huang, S., Liu, Y., Wei, S., Chen, G., Gong, Z., Ouyang, G., 2020. Hollow carbon nanobubbles-coated solid-phase microextraction fibers for the sensitive detection of organic pollutants. Analytica Chimica Acta 1097, 85-93.Zhang, P., Lu, S., Li, J., Chang, X., 2020. 1D and 2D Nuclear magnetic resonance (NMR) relaxation behaviors of protons in clay, kerogen and oil-bearing shale rocks. Marine and Petroleum Geology 114, 104210.Gas Chromatography/GC×GC/GC-MSAmaral, M.S.S., Nolvachai, Y., Marriott, P.J., 2020. Comprehensive two-dimensional gas chromatography advances in technology and applications - biennial update. Analytical Chemistry 92, 85-104.Chiu, H.-H., Kuo, C.-H., 2020. Gas chromatography-mass spectrometry-based analytical strategies for fatty acid analysis in biological samples. Journal of Food and Drug Analysis 28, 60-73.Crucello, J., Pierone, D.V., Hantao, L.W., 2020. Simple and cost-effective determination of polychlorinated biphenyls in insulating oils using an ionic liquid-based stationary phase and flow modulated comprehensive two-dimensional gas chromatography with electron capture detection. Journal of Chromatography A 1610, 460530.Hashemi-Nasab, F.S., Parastar, H., 2020. Pattern recognition analysis of gas chromatographic and infrared spectroscopic fingerprints of crude oil for source identification. Microchemical Journal 153, 104326.Li, Y., Pang, T., Shi, J., Deng, X., Kong, G., Lu, X., 2020. Conversion method for linear retention indices in gas chromatography acquired using n-alkanes and n-fatty acid methyl esters. Chinese Journal of Chromatography 38, 244-249.Liao, P.-H., Yang, H.-H., Wu, P.-C., Abu Bakar, N.H., Urban, P.L., 2020. On-line coupling of simultaneous distillation–extraction using the Likens–Nickerson apparatus with gas chromatography. Analytical Chemistry 92, 1228-1235.Nunes, V.O., Silva, R.V.S., Romeiro, G.A., Azevedo, D.A., 2020. The speciation of the organic compounds of slow pyrolysis bio-oils from Brazilian tropical seed cake fruits using high-resolution techniques: GC?×?GC-TOFMS and ESI(±)-Orbitrap HRMS. Microchemical Journal 153, 104514.Schena, T., Lazzari, E., Primaz, C., Canielas Krause, L., Machado, M.E., Bastos Caram?o, E., 2020. Upgrading of coconut fibers bio-oil: An investigation by GC×GC/TOFMS. Journal of Environmental Chemical Engineering 8, 103662.Sojinu, O.S., 2020. Preliminary evaluation of bitumen contamination in environmental samples using comprehensive gas chromatography GC×GC – Time of flight mass spectrometry (GC×GC-TOFMS). Environmental Forensics 21, 79-86.van Mourik, L.M., Lava, R., O'Brien, J., Leonards, P.E.G., de Boer, J., Ricci, M., 2020. The underlying challenges that arise when analysing short-chain chlorinated paraffins in environmental matrices. Journal of Chromatography A 1610, 460550.Xie, S.-M., Chen, X.-X., Zhang, J.-H., Yuan, L.-M., 2020. Gas chromatographic separation of enantiomers on novel chiral stationary phases. TrAC Trends in Analytical Chemistry 124, 115808.Imaging: AFMMüller, H., Marozava, S., Probst, A.J., Meckenstock, R.U., 2020. Groundwater cable bacteria conserve energy by sulfur disproportionation. The ISME Journal 14, 623-634.Yamada, Y., Guillemette, R., Baudoux, A.-C., Patel, N., Azam, F., 2020. Viral attachment to biotic and abiotic surfaces in seawater. Applied and Environmental Microbiology 86, e01687-01619.Imaging: SEM, TEM, HIMAkhondzadeh, H., Keshavarz, A., Al-Yaseri, A.Z., Ali, M., Awan, F.U.R., Wang, X., Yang, Y., Iglauer, S., Lebedev, M., 2020. Pore-scale analysis of coal cleat network evolution through liquid nitrogen treatment: A Micro-Computed Tomography investigation. International Journal of Coal Geology 219, 103370.Balfourier, A., Luciani, N., Wang, G., Lelong, G., Ersen, O., Khelfa, A., Alloyeau, D., Gazeau, F., Carn, F., 2020. Unexpected intracellular biodegradation and recrystallization of gold nanoparticles. Proceedings of the National Academy of Sciences 117, 103-113.Bonneville, S., Delpomdor, F., Préat, A., Chevalier, C., Araki, T., Kazemian, M., Steele, A., Schreiber, A., Wirth, R., Benning, L.G., 2020. Molecular identification of fungi microfossils in a Neoproterozoic shale rock. Science Advances 6, eaax7599.Cui, L., Liu, W., Zhang, X., 2020. Phosphatized microbial fossils from the lowest Cambrian of South China and their ecological and environmental implications for the Kuanchuanpu biota. Precambrian Research 338, 105560.Fu, Y., Chen, Z., Zhou, S., Wei, S., 2020. Comparative study of the materials and lacquering techniques of the lacquer objects from Warring States Period China. Journal of Archaeological Science 114, 105060.Goodman, A., Sanguinito, S., Kutchko, B., Natesakhawat, S., Cvetic, P., Allen, A.J., 2020. Shale pore alteration: Potential implications for hydrocarbon extraction and CO2 storage. Fuel 265, 116930.Goral, J., Panja, P., Deo, M., Andrew, M., Linden, S., Schwarz, J.-O., Wiegmann, A., 2020. Confinement effect on porosity and permeability of shales. Scientific Reports 10, 49.Hackley, P.C., Araujo, C.V., Borrego, A.G., Bouzinos, A., Cardott, B.J., Carvajal-Ortiz, H., López Cely, M.R., Chabalala, V., Crosdale, P.J., Demchuk, T.D., Eble, C.F., Flores, D., Furmann, A., Gentzis, T., Gon?alves, P.A., Guvad, C., Hámor-Vidó, M., Jelonek, I., Johnston, M.N., Juliao-Lemus, T., Kalaitzidis, S., Knowles, W.R., Kus, J., Li, Z., Macleod, G., Mastalerz, M., Menezes, T.R., Ocubalidet, S., Orban, R., Pickel, W., Ranasinghe, P., Ribeiro, J., Gómez Rojas, O.P., Ruiz-Monroy, R., Schmidt, J.S., Seyedolali, A., Siavalas, G., Suarez-Ruiz, I., Vargas, C.V., Valentine, B.J., Wagner, N., Wrolson, B., Jaramillo Zapata, J.E., 2020. Testing reproducibility of vitrinite and solid bitumen reflectance measurements in North American unconventional source-rock reservoir petroleum systems. Marine and Petroleum Geology 114, 104172.Han, H., Pang, P., Zhong, N., Luo, Q., Ma, Y., Gao, Y., 2020. The pore characteristics and gas potential of the Jurassic continental shales in the middle-small basins, northwest China. Journal of Petroleum Science and Engineering 188, 106873.Hand, E., 2020. Cheap shots. Science 367, 354-358.Hou, H., Shao, L., Tang, Y., Zhao, S., Yuan, Y., Li, Y., Mu, G., Zhou, Y., Liang, G., Zhang, J., 2020. Quantitative characterization of low-rank coal reservoirs in the southern Junggar Basin, NW China: Implications for pore structure evolution around the first coalification jump. Marine and Petroleum Geology 113, 104165.Jacquemot, P., Viennet, J.-C., Bernard, S., Le Guillou, C., Rigaud, B., Delbes, L., Georgelin, T., Jaber, M., 2019. The degradation of organic compounds impacts the crystallization of clay minerals and vice versa. Scientific Reports 9, 20251.Kato, K., Shinoda, T., Nagao, R., Akimoto, S., Suzuki, T., Dohmae, N., Chen, M., Allakhverdiev, S.I., Shen, J.-R., Akita, F., Miyazaki, N., Tomo, T., 2020. Structural basis for the adaptation and function of chlorophyll f in photosystem I. Nature Communications 11, 238.Khan, I., Zhong, N., Luo, Q., Ai, J., Yao, L., Luo, P., 2020. Maceral composition and origin of organic matter input in Neoproterozoic–Lower Cambrian organic-rich shales of Salt Range Formation, upper Indus Basin, Pakistan. International Journal of Coal Geology 217, 103319.Kutchko, B., Sanguinito, S., Natesakhawat, S., Cvetic, P., Culp, J.T., Goodman, A., 2020. Quantifying pore scale and matrix interactions of SCCO2 with the Marcellus shale. Fuel 266, 116928.Lin, K., Huang, X., Zhao, Y.-P., 2019. Combining image recognition and simulation to reproduce the adsorption/desorption behaviors of shale gas. Energy & Fuels 34, 258-269.Lin, X., Huang, M., Chen, H., Wang, J., Wang, R., 2019. Influence of different polar solvent extraction on pore structure in shale. Acta Petrolei Sinica 40, 1485-1494.Liu, X., Lai, J., Fan, X., Shu, H., Wang, G., Ma, X., Liu, M., Guan, M., Luo, Y., 2020. Insights in the pore structure, fluid mobility and oiliness in oil shales of Paleogene Funing Formation in Subei Basin, China. Marine and Petroleum Geology 114, 104228.Mansoori Mosleh, F., Mortazavi, Y., Hosseinpour, N., Khodadadi, A.A., 2020. Asphaltene adsorption onto carbonaceous nanostructures. Energy & Fuels 34, 211-224.Payandi-Rolland, D., Shirokova, L.S., Nakhle, P., Tesfa, M., Abdou, A., Causserand, C., Lartiges, B., Rols, J.-L., Guérin, F., Bénézeth, P., Pokrovsky, O.S., 2020. Aerobic release and biodegradation of dissolved organic matter from frozen peat: Effects of temperature and heterotrophic bacteria. Chemical Geology 536, 119448.Senatore, G., Mastroleo, F., Leys, N., Mauriello, G., 2020. Growth of Lactobacillus reuteri DSM17938 under two simulated microgravity systems: Changes in reuterin production, gastrointestinal passage resistance, and stress genes expression response. Astrobiology 20, 1-14.Shen, P., Li, G., Li, B., Li, X., Liang, Y., Lv, Q., 2020. Permeability measurement and discovery of dissociation process of hydrate sediments. Journal of Natural Gas Science and Engineering 75, 103155.Song, D., Tuo, J., Wang, Y., Wu, C., Zhang, M., 2019. Research advances on characteristics of nanopore structure of organic-rich shales. Acta Sedimentologica Sinica 37, 1309-1324.Song, D., Tuo, J., Wu, C., Zhang, M., Su, L., 2020. Comparison of pore evolution for a Mesoproterozoic marine shale and a Triassic terrestrial mudstone during artificial maturation experiments. Journal of Natural Gas Science and Engineering 75, 103153.Song, L., Carr, T.R., 2020. The pore structural evolution of the Marcellus and Mahantango shales, Appalachian Basin. Marine and Petroleum Geology 114, 104226.Wang, C., Wu, K., Scott, G.G., Akisanya, A.R., Gan, Q., Zhou, Y., 2020. A new method for pore structure quantification and pore network extraction from SEM images. Energy & Fuels 34, 82-94.Xu, S., Gou, Q., Hao, F., Zhang, B., Shu, Z., Lu, Y., Wang, Y., 2020. Shale pore structure characteristics of the high and low productivity wells, Jiaoshiba shale gas field, Sichuan Basin, China: Dominated by lithofacies or preservation condition? Marine and Petroleum Geology 114, 104211.Yang, W., He, S., Iglauer, S., Guo, X., Zhai, G., Zhou, Z., Dong, T., Tao, Z., Wei, S., 2020. Porosity characteristics of different lithofacies in marine shale: A case study of Neoproterozoic Sinian Doushantuo formation in Yichang area, China. Journal of Petroleum Science and Engineering 187, 106856.Zhang, K., Jia, C., Song, Y., Jiang, S., Jiang, Z., Wen, M., Huang, Y., Liu, X., Jiang, T., Peng, J., Wang, X., Xia, Q., Li, B., Li, X., Liu, T., 2020. Analysis of Lower Cambrian shale gas composition, source and accumulation pattern in different tectonic backgrounds: A case study of Weiyuan Block in the Upper Yangtze region and Xiuwu Basin in the Lower Yangtze region. Fuel 263, 115978.Zhou, H., Chen, J., Li, H., Quan, K., Zhang, Y., Qiu, H., 2020. Imidazolium ionic liquid-enhanced poly(quinine)-modified silica as a new multi-mode chromatographic stationary phase for separation of achiral and chiral compounds. Talanta 211, 120743.Imaging: Xray CTAkhondzadeh, H., Keshavarz, A., Al-Yaseri, A.Z., Ali, M., Awan, F.U.R., Wang, X., Yang, Y., Iglauer, S., Lebedev, M., 2020. Pore-scale analysis of coal cleat network evolution through liquid nitrogen treatment: A Micro-Computed Tomography investigation. International Journal of Coal Geology 219, 103370.Goral, J., Panja, P., Deo, M., Andrew, M., Linden, S., Schwarz, J.-O., Wiegmann, A., 2020. Confinement effect on porosity and permeability of shales. Scientific Reports 10, 49.Jing, Z., Balucan, R.D., Underschultz, J.R., Pan, S., Steel, K.M., 2020. Chemical stimulation for enhancing coal seam permeability: Laboratory study into permeability variation and coal structure examination. International Journal of Coal Geology 219, 103375.Liu, X., Lai, J., Fan, X., Shu, H., Wang, G., Ma, X., Liu, M., Guan, M., Luo, Y., 2020. Insights in the pore structure, fluid mobility and oiliness in oil shales of Paleogene Funing Formation in Subei Basin, China. Marine and Petroleum Geology 114, 104228.Marone, F., Schlepütz, C.M., Marti, S., Fusseis, F., Velásquez-Parra, A., Griffa, M., Jiménez-Martínez, J., Dobson, K.J., Stampanoni, M., 2020. Time resolved in situ X-ray tomographic microscopy unraveling dynamic processes in geologic systems. Frontiers in Earth Science 7, 346. doi: 310.3389/feart.2019. 00346.Schiffbauer, J.D., Selly, T., Jacquet, S.M., Merz, R.A., Nelson, L.L., Strange, M.A., Cai, Y., Smith, E.F., 2020. Discovery of bilaterian-type through-guts in cloudinomorphs from the terminal Ediacaran Period. Nature Communications 11, 205.Stewart, T.A., Lemberg, J.B., Taft, N.K., Yoo, I., Daeschler, E.B., Shubin, N.H., 2020. Fin ray patterns at the fin-to-limb transition. Proceedings of the National Academy of Sciences 117, 1612-1620.Zhang, W., Liang, J., Wei, J., Lu, J.a., Su, P., Lin, L., Huang, W., Guo, Y., Deng, W., Yang, X., Wan, Z., 2020. Geological and geophysical features of and controls on occurrence and accumulation of gas hydrates in the first offshore gas-hydrate production test region in the Shenhu area, Northern South China Sea. Marine and Petroleum Geology 114, 104191.Liquid Chromatography/LC-MS/SFCBernardin, M., Masle, A.L., Bessueille-Barbier, F., Lienemann, C.-P., Heinisch, S., 2020. Comprehensive two-dimensional liquid chromatography with inductively coupled plasma mass spectrometry detection for the characterization of sulfur, vanadium and nickel compounds in petroleum products. Journal of Chromatography A 1611, 460605.Broeckhoven, K., Desmet, G., 2020. Advances and challenges in extremely high-pressure liquid chromatography in current and future analytical scale column formats. Analytical Chemistry 92, 554-560.Caputo, M., Lyles, J.T., Salazar, M., Quave, C.L., 2020. LEGO MINDSTORMS fraction collector: A low-cost tool for a preparative high performance liquid chromatography system. Analytical Chemistry 92, 1687-1690.Cerrato, A., Cannazza, G., Capriotti, A.L., Citti, C., La Barbera, G., Laganà, A., Montone, C.M., Piovesana, S., Cavaliere, C., 2020. A new software-assisted analytical workflow based on high-resolution mass spectrometry for the systematic study of phenolic compounds in complex matrices. Talanta 209, 120573.Hohrenk, L.L., Itzel, F., Baetz, N., Tuerk, J., Vosough, M., Schmidt, T.C., 2020. Comparison of software tools for liquid chromatography–high-resolution mass spectrometry data processing in nontarget screening of environmental samples. Analytical Chemistry 92, 1898-1907.Kaplitz, A.S., Kresge, G.A., Selover, B., Horvat, L., Franklin, E.G., Godinho, J.M., Grinias, K.M., Foster, S.W., Davis, J.J., Grinias, J.P., 2020. High-throughput and ultrafast liquid chromatography. Analytical Chemistry 92, 67-84.Korf, A., Fouquet, T., Schmid, R., Hayen, H., Hagenhoff, S., 2020. Expanding the Kendrick mass plot toolbox in MZmine 2 to enable rapid polymer characterization in liquid chromatography?mass spectrometry data sets. Analytical Chemistry 92, 628-633.Koshel, B., Birdsall, R., Chen, W., 2020. Two-dimensional liquid chromatography coupled to mass spectrometry for impurity analysis of dye-conjugated oligonucleotides. Journal of Chromatography B 1137, 121906.Melnikov, A.D., Tsentalovich, Y.P., Yanshole, V.V., 2020. Deep learning for the precise peak detection in high-resolution LC–MS data. Analytical Chemistry 92, 588-592.Ovchinnikov, D.V., Pokrovskiy, O.I., Kosyakov, D.S., Bogolitsyn, K.G., Ul'yanovskii, N.V., Falev, D.I., 2020. Evaluation of temperature and pressure effects on retention in supercritical fluid chromatography on polar stationary phases. Journal of Chromatography A 1610, 460600.Pham, H.-T.-T., Kim, H.-W., Han, S., Ryu, B., Doan, T.-P., An, J.-P., Tran, V.-O., Oh, W.-K., 2019. Development of a building block strategy to target the classification, identification, and metabolite profiling of oleanane triterpenoids in Gymnema sylvestre using UHPLC-qTOF/MS. Journal of Natural Products 82, 3249-3266.Reymond, C., Dubuis, A., Le Masle, A., Colas, C., Chahen, L., Destandau, E., Charon, N., 2020. Characterization of liquid–liquid extraction fractions from lignocellulosic biomass by high performance liquid chromatography hyphenated to tandem high-resolution mass spectrometry. Journal of Chromatography A 1610, 460569.Sorensen, M.J., Miller, K.E., Jorgenson, J.W., Kennedy, R.T., 2020. Ultrahigh-Performance capillary liquid chromatography-mass spectrometry at 35?kpsi for separation of lipids. Journal of Chromatography A 1611, 460575.Yu, Y., Li, G., Wu, D., Liu, J., Chen, J., Hu, N., Wang, H., Wang, P., Wu, Y., 2020. Thiol radical-based chemical isotope labelling for sterols quantitation through high performance liquid chromatography-tandem mass spectrometry analysis. Analytica Chimica Acta 1097, 110-119.Zhou, H., Chen, J., Li, H., Quan, K., Zhang, Y., Qiu, H., 2020. Imidazolium ionic liquid-enhanced poly(quinine)-modified silica as a new multi-mode chromatographic stationary phase for separation of achiral and chiral compounds. Talanta 211, 120743.Zyakun, A.M., Kochetkov, V.V., Zakharchenko, V.N., Baskunov, B.P., Peshenko, V.P., Laurinavichius, K.S., Siunova, T.V., Anokhina, T.O., Boronin, A.M., 2019. Application of high-performance liquid chromatography/high resolution mass spectrometry to the investigation of the biodegradation and transformation of phenanthrene by a plasmid bearing rhizosphere bacteria Pseudomonas aureofaciens. Journal of Analytical Chemistry 74, 1355-1361.Mass Spectroscopy/ICR-FTMS/OrbitrapArevalo Jr, R., Ni, Z., Danell, R.M., 2020. Mass spectrometry and planetary exploration: A brief review and future projection. Journal of Mass Spectrometry 55, e4454.Gautier, T., Danger, G., Mousis, O., Duvernay, F., Vuitton, V., Flandinet, L., Thissen, R., Orthous-Daunay, F.R., Ruf, A., Chiavassa, T., d'Hendecourt, L.S., 2020. Laboratory experiments to unveil the molecular reactivity occurring during the processing of ices in the protosolar nebula. Earth and Planetary Science Letters 531, 116011.Han, Y., Poetz, S., Mahlstedt, N., Horsfield, B., 2020. On the release of acidic NSO compounds from the oil-mature Barnett Shale using different solvents. Journal of Petroleum Science and Engineering 185, 106605.Liu, Y., Ye, Q., Huang, W.-L., Feng, L., Wang, Y.-H., Xie, Z., Yong, S.-S., Zhang, S., Jiang, B., Zheng, Y., Wang, J.-J., 2020. Spectroscopic and molecular-level characteristics of dissolved organic matter in the Pearl River Estuary, South China. Science of The Total Environment 710, 136307.Miranda, M.L., Osterholz, H., Giebel, H.A., Bruhnke, P., Dittmar, T., Zielinski, O., 2020. Impact of UV radiation on DOM transformation on molecular level using FT-ICR-MS and PARAFAC. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 230, 118027.Nunes, V.O., Silva, R.V.S., Romeiro, G.A., Azevedo, D.A., 2020. The speciation of the organic compounds of slow pyrolysis bio-oils from Brazilian tropical seed cake fruits using high-resolution techniques: GC?×?GC-TOFMS and ESI(±)-Orbitrap HRMS. Microchemical Journal 153, 104514.Qi, Y., Fu, P., Li, S., Ma, C., Liu, C., Volmer, D.A., 2020. Assessment of molecular diversity of lignin products by various ionization techniques and high-resolution mass spectrometry. Science of The Total Environment 713, 136573.Reymond, C., Dubuis, A., Le Masle, A., Colas, C., Chahen, L., Destandau, E., Charon, N., 2020. Characterization of liquid–liquid extraction fractions from lignocellulosic biomass by high performance liquid chromatography hyphenated to tandem high-resolution mass spectrometry. Journal of Chromatography A 1610, 460569.Wang, H., Ge, D., Cheng, Z., Zhu, N., Yuan, H., Lou, Z., 2020. Improved understanding of dissolved organic matter transformation in concentrated leachate induced by hydroxyl radicals and reactive chlorine species. Journal of Hazardous Materials 397, 121702.Xu, L., Li, X., Wang, X., Song, A., Han, F., 2020. A feasible strategy based on isotopic fine structures to enhance the reliability of metabolite identification by Fourier transform ion cyclotron resonance mass spectrometry. Rapid Communications in Mass Spectrometry 34, e8560.Yu, K., Duan, Y., Gan, Y., Zhang, Y., Zhao, K., 2020. Anthropogenic influences on dissolved organic matter transport in high arsenic groundwater: Insights from stable carbon isotope analysis and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. Science of The Total Environment 708, 135162.Zhang, P., Huang, P., Xu, X., Sun, H., Jiang, B., Liao, Y., 2020. Spectroscopic and molecular characterization of biochar-derived dissolved organic matter and the associations with soil microbial responses. Science of The Total Environment 708, 134619.Zhang, Y.-Y., Wei, X.-Y., Lv, J.-H., Jiang, H., Liu, F.-J., Liu, G.-H., Zong, Z.-M., 2019. Characterization of nitrogen-containing aromatics in Baiyinhua lignite and its soluble portions from thermal dissolution. Chinese Journal of Chemical Engineering 27, 2783-2787.Mass Spectroscopy/OtherArevalo Jr, R., Ni, Z., Danell, R.M., 2020. Mass spectrometry and planetary exploration: A brief review and future projection. Journal of Mass Spectrometry 55, e4454.Bittremieux, W., 2020. spectrum_utils: A Python package for mass spectrometry data processing and visualization. Analytical Chemistry 92, 659-661.Chen, X., Zhu, L., Cui, C., Zhu, Y., Zhou, Z., Qi, F., 2020. In situ atmospheric pressure photoionization mass spectrometric monitoring of initial pyrolysis products of biomass in real time. Analytical Chemistry 92, 603-606.Colby, S.M., Nu?ez, J.R., Hodas, N.O., Corley, C.D., Renslow, R.R., 2020. Deep learning to generate in silico chemical property libraries and candidate molecules for small molecule identification in complex samples. 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Proceedings of the National Academy of Sciences 117, 883-888.Vance, S.D., Melwani Daswani, M., 2020. Serpentinite and the search for life beyond Earth. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20180421.Weber, A.L., Rios, A.C., 2019. Imidazolium-catalyzed synthesis of an imidazolium catalyst. Origins of Life and Evolution of Biospheres 49, 199-211.Williams, T.A., Cox, C.J., Foster, P.G., Sz?ll?si, G.J., Embley, T.M., 2020. Phylogenomics provides robust support for a two-domains tree of life. Nature Ecology & Evolution 4, 138-147.Xavier, J.C., 2020. The early origin of cooperation. Nature Ecology & Evolution 4, 18-19.Hominid EvolutionBailey, S.E., Kupczik, K., Hublin, J.-J., Antón, S.C., 2020. Reply to Scott et al: A closer look at the 3-rooted lower second molar of an archaic human from Xiahe. Proceedings of the National Academy of Sciences 117, 39.Brasseur, B., 2020. A younger “earliest human migration” to Southeast Asia. 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Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20180431.McCaig, A.M., Früh-Green, G.L., Kelemen, P., Teagle, D.A.H., 2020. Serpentinite in the Earth system. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20190332.Prokofiev, V.Y., Banks, D.A., Lobanov, K.V., Selektor, S.L., Milichko, V.A., Akinfiev, N.N., Borovikov, A.A., Lüders, V., Chicherov, M.V., 2020. Exceptional concentrations of gold nanoparticles in 1,7 Ga fluid inclusions from the Kola superdeep borehole, northwest Russia. Scientific Reports 10, 1108.Qiu, Y., Wang, X.-L., Liu, X., Cao, J., Liu, Y.-F., Xi, B.-B., Gao, W.-L., 2020. In situ Raman spectroscopic quantification of CH4–CO2 mixture: application to fluid inclusions hosted in quartz veins from the Longmaxi Formation shales in Sichuan Basin, southwestern China. Petroleum Science 17, 23–35.So?nicka, M., Lüders, V., 2020. Fluid inclusion evidence for low-temperature thermochemical sulfate reduction (TSR) of dry coal gas in Upper Permian carbonate reservoirs (Zechstein, Ca2) in the North German Basin. Chemical Geology 534, 119453.Yu, C., Zhong, R., Bai, R., Wang, Y., Ling, Y., 2020. A method to predict the homogenization temperatures of easily decrepitated fluid inclusions. Ore Geology Reviews 117, 103311.General InterestFayet, A.L., Hansen, E.S., Biro, D., 2020. Evidence of tool use in a seabird. Proceedings of the National Academy of Sciences 117, 1277-1279.Norouzi, N., Fani, M., Ziarani, Z.K., 2020. The fall of oil Age: A scenario planning approach over the last peak oil of human history by 2040. Journal of Petroleum Science and Engineering 188, 106827.Pais, S.C., 2019. The plasma compression fusion device—enabling nuclear fusion ignition. IEEE Transactions on Plasma Science 47, 5119-5124.Waldrop, M.M., 2020. News Feature: Small-scale fusion tackles energy, space applications. 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Origin of sulfate-rich fluids in the Early Triassic Montney Formation, Western Canadian Sedimentary Basin. Marine and Petroleum Geology 114, 104236.Mayhew, L.E., Ellison, E.T., 2020. A synthesis and meta-analysis of the Fe chemistry of serpentinites and serpentine minerals. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20180420.McCaig, A.M., Früh-Green, G.L., Kelemen, P., Teagle, D.A.H., 2020. Serpentinite in the Earth system. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20190332.McCollom, T.M., Klein, F., Solheid, P., Moskowitz, B., 2020. The effect of pH on rates of reaction and hydrogen generation during serpentinization. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20180428.Robinson, K.J., Fecteau, K.M., Gould, I.R., Hartnett, H.E., Williams, L.B., Shock, E.L., 2020. 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Analytical Chemistry 92, 2034-2042.Mathematical Geochemistry/Phase BehaviorChen, C., Sun, J., Zhang, Y., Mu, J., Li, W., Song, Y., 2020. Adsorption characteristics of CH4 and CO2 in organic-inorganic slit pores. Fuel 265, 116969.Choudhary, N., Narayanan Nair, A.K., Che Ruslan, M.F.A., Sun, S., 2019. Bulk and interfacial properties of decane in the presence of carbon dioxide, methane, and their mixture. Scientific Reports 9, 19784.de Oliveira, F.C., Khani, S., Maia, J.M., Tavares, F.W., 2020. Concentration and solvent effects on structural, dynamical, and rheological properties of asphaltene suspensions. Energy & Fuels 34, 1071-1081.Du, F., Nojabaei, B., 2020. A black-oil approach to model produced gas injection in both conventional and tight oil-rich reservoirs to enhance oil recovery. Fuel 263, 116680.Elkahky, S., Lagat, C., Sarmadivaleh, M., Barifcani, A., 2019. A comparative study of density estimation of asphaltene structures using group contribution methods and molecular dynamic simulations for an Australian oil field. Journal of Petroleum Exploration and Production Technology 9, 2699-2708.Liu, X.-Q., Li, M., Zhang, C., Fang, R., Zhong, N., Xue, Y., Zhou, Y., Jiang, W., Chen, X.-Y., 2020. Mechanistic insight into the optimal recovery efficiency of CBM in sub-bituminous coal through molecular simulation. Fuel 266, 117137.Luan, Y., Liu, B., Hao, P., Zhan, K., Liu, J., 2020. Oil displacement by supercritical CO2 in a water cut dead-end pore: Molecular dynamics simulation. Journal of Petroleum Science and Engineering 188, 106899.Matsui, H., Jia, J., Tsuji, T., Liang, Y., Masuda, Y., 2020. Microsecond simulation study on the replacement of methane in methane hydrate by carbon dioxide, nitrogen, and carbon dioxide–nitrogen mixtures. Fuel 263, 116640.Paricaud, P., Ndjaka, A., Catoire, L., 2020. Prediction of the flash points of multicomponent systems: Applications to solvent blends, gasoline, diesel, biodiesels and jet fuels. Fuel 263, 116534.Wang, Y., Lian, J., Xue, Y., Liu, P., Dai, B., Lin, H., Han, S., 2020. The pyrolysis of vitrinite and inertinite by a combination of quantum chemistry calculation and thermogravimetry-mass spectrometry. Fuel 264, 116794.Yang, S., 2020. An analytical model for fluid imbibition in organic nanopores. Transport in Porous Media 131, 595-615.Yu, H., Fan, J., Xia, J., Liu, H., Wu, H., 2020. Multiscale gas transport behavior in heterogeneous shale matrix consisting of organic and inorganic nanopores. Journal of Natural Gas Science and Engineering 75, 103139.Zhang, Y., Fang, T., Ding, B., Wang, W., Yan, Y., Li, Z., Guo, W., Zhang, J., 2020. Migration of oil/methane mixture in shale inorganic nano-pore throat: A molecular dynamics simulation study. 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Biogeosciences 17, 361-379.Lam, B.R., Barge, L.M., Noell, A.C., Nealson, K.H., 2019. Detecting endogenous microbial metabolism and differentiating between abiotic and biotic signals observed by bioelectrochemical systems in soils. Astrobiology 20, 39-52.Lu, G.-Y., Imai, H., Ikeya, K., Sumida, H., Watanabe, A., 2020. Black carbon as a significant component of aromatic carbon in surface soils and its importance is enhanced in volcanic ash soil profiles. Organic Geochemistry 140, 103957.Sasmito, S.D., Kuzyakov, Y., Lubis, A.A., Murdiyarso, D., Hutley, L.B., Bachri, S., Friess, D.A., Martius, C., Borchard, N., 2020. Organic carbon burial and sources in soils of coastal mudflat and mangrove ecosystems. CATENA 187, 104414.Su, C., Zhang, M., Lin, L., Yu, G., Zhong, H., Chong, Y., 2020. Reduction of iron oxides and microbial community composition in iron-rich soils with different organic carbon as electron donors. International Biodeterioration & Biodegradation 148, 104881.Teunissen van Manen, M.L., Jansen, B., Cuesta, F., León-Yánez, S., Gosling, W.D., 2020. From leaf to soil: n-alkane signal preservation, despite degradation along an environmental gradient in the tropical Andes. Biogeosciences Discussions 2020, 1-31.Volkov, D.S., Rogova, O.B., Proskurnin, M.A., 2020. Photoacoustic and photothermal methods in spectroscopy and characterization of soils and soil organic matter. Photoacoustics 17, 100151.Windirsch, T., Grosse, G., Ulrich, M., Schirrmeister, L., Fedorov, A.N., Konstantinov, P.Y., Fuchs, M., Jongejans, L.L., Wolter, J., Strauss, J., 2020. Organic carbon characteristics in ice-rich permafrost in Alas and Yedoma deposits, Central Yakutia, Siberia. Biogeosciences Discussions 2020, 1-31.Zhang, P., Huang, P., Xu, X., Sun, H., Jiang, B., Liao, Y., 2020. Spectroscopic and molecular characterization of biochar-derived dissolved organic matter and the associations with soil microbial responses. Science of The Total Environment 708, 134619.Remote Sensing-Hydrocarbon SeepageAttias, E., Amalokwu, K., Watts, M., Falcon-Suarez, I.H., North, L., Hu, G.W., Best, A.I., Weitemeyer, K., Minshull, T.A., 2020. Gas hydrate quantification at a pockmark offshore Norway from joint effective medium modelling of resistivity and seismic velocity. Marine and Petroleum Geology 113, 104151.Borrelli, C., Gabitov, R.I., Liu, M.C., Hertwig, A.T., Panieri, G., 2020. The benthic foraminiferal δ34S records flux and timing of paleo methane emissions. Scientific Reports 10, 1304.Chan, E.W., Shiller, A.M., Joung, D.J., Arrington, E.C., Valentine, D.L., Redmond, M.C., Breier, J.A., Socolofsky, S.A., Kessler, J.D., 2020. Investigations of aerobic methane oxidation in two marine seep environments: Part 2 - Isotopic kinetics. Journal of Geophysical Research: Oceans 124, 8392-8399.Chen, F., Wang, X., Li, N., Cao, J., Bayon, G., Peckmann, J., Hu, Y., Gong, S., Cheng, H., Edwards, R.L., Ning, Y., Jin, M., Huang, H., Wu, C., Sun, Y., Chen, H., Zhou, Y., Chen, D., Feng, D., 2019. Gas hydrate dissociation during sea-level highstand inferred from U/Th dating of seep carbonate from the south China Sea. Geophysical Research Letters 46, 13928-13938.Chen, L., Jin, M., Wang, X., Wang, H., Li, N., 2020. The effects of diagenetic processes and fluid migration on rare earth element and organic matter distribution in seep-related sediments: A case study from the South China Sea. Journal of Asian Earth Sciences 191, 104233.Chen, N.-C., Yang, T.F., Hong, W.-L., Yu, T.-L., Lin, I.-T., Wang, P.-L., Lin, S., Su, C.-C., Shen, C.-C., Wang, Y., Lin, L.-H., 2020. Discharge of deeply rooted fluids from submarine mud volcanism in the Taiwan accretionary prism. Scientific Reports 10, 381.Chen, Y., Deng, B., Zhang, J., 2020. Shallow gas in the Holocene mud wedge along the inner East China Sea shelf. Marine and Petroleum Geology 114, 104233.Cordova-Gonzalez, A., Birgel, D., Kappler, A., Peckmann, J., 2020. Carbon stable isotope patterns of cyclic terpenoids: A comparison of cultured alkaliphilic aerobic methanotrophic bacteria and methane-seep environments. Organic Geochemistry 139, 103940.Drake, P., 2020. Comment to “More than ten years of Lusi: A review of facts, coincidences, and past and future studies” by Miller and Mazzini (2018): Taking the trigger debate above ground. Marine and Petroleum Geology 113, 104079.de Gouw, J.A., Veefkind, J.P., Roosenbrand, E., Dix, B., Lin, J.C., Landgraf, J., Levelt, P.F., 2020. Daily satellite observations of methane from oil and gas production regions in the United States. Scientific Reports 10, 1379.Huang, H., Wang, X., Gong, S., Krake, N., Jin, M., Li, N., Birgel, D., Peckmann, J., Cheng, M., Roberts, H.H., Chen, D., Feng, D., 2020. New constraints on the formation of hydrocarbon-derived low magnesium calcite at brine seeps in the Gulf of Mexico. Sedimentary Geology 398, 105572.Miyajima, Y., Watanabe, Y., Goto, A.S., Jenkins, R.G., Sakai, S., Matsumoto, R., Hasegawa, T., 2020. Archaeal lipid biomarker as a tool to constrain the origin of methane at ancient methane seeps: Insight into subsurface fluid flow in the geological past. Journal of Asian Earth Sciences 189, 104134.Panagiotopoulos, I.P., Paraschos, F., Rousakis, G., Hatzianestis, I., Parinos, C., Morfis, I., Gogou, A., 2020. Assessment of the eruptive activity and identification of the mud breccia's source in the Olimpi mud volcano field, Eastern Mediterranean. Deep Sea Research Part II: Topical Studies in Oceanography 171, 104701.Phrampus, B.J., Lee, T.R., Wood, W.T., 2020. A global probabilistic prediction of cold seeps and associated SEAfloor FLuid ExpulsionAnomalies (SEAFLEAs). Geochemistry, Geophysics, Geosystems 21, e2019GC008747.Remizovschi, A., Carpa, R., Forray, F.L., Chiriac, C., Roba, C.-A., Beldean-Galea, S., Andrei, A.-?., Szekeres, E., Baricz, A., Lupan, I., Knut, R., Coman, C., 2020. Mud volcanoes and the presence of PAHs. Scientific Reports 10, 1253.Snyder, G.T., Sano, Y., Takahata, N., Matsumoto, R., Kakizaki, Y., Tomaru, H., 2020. Magmatic fluids play a role in the development of active gas chimneys and massive gas hydrates in the Japan Sea. Chemical Geology 535, 119462.Sun, Y., Gong, S., Li, N., Peckmann, J., Jin, M., Roberts, H.H., Chen, D., Feng, D., 2020. A new approach to discern the hydrocarbon sources (oil vs. methane) of authigenic carbonates forming at marine seeps. Marine and Petroleum Geology 114, 104230.Taleb, F., Lemaire, M., Garziglia, S., Marsset, T., Sultan, N., 2020. Seafloor depressions on the Nigerian margin: Seabed morphology and sub-seabed hydrate distribution. Marine and Petroleum Geology 114, 104175.?orsteinsdóttir, G.V., Blischke, A., Sigurbj?rnsdóttir, M.A., ?skarsson, F., Arnarson, ?.S., Magnússon, K.P., Vilhelmsson, O., 2019. Gas seepage pockmark microbiomes suggest the presence of sedimentary coal seams in the ?xarfj?r?ur graben of northeastern Iceland. Canadian Journal of Microbiology 66, 25-38.Yu, X., Millet, D.B., Wells, K.C., Griffis, T.J., Chen, X., Baker, J.M., Conley, S.A., Smith, M.L., Gvakharia, A., Kort, E.A., Plant, G., Wood, J.D., 2020. Top-down constraints on methane point source emissions from animal agriculture and waste based on new airborne measurements in the U.S. Upper Midwest. Journal of Geophysical Research: Biogeosciences 125, e2019JG005429.Zander, T., Haeckel, M., Klaucke, I., Bialas, J., Klaeschen, D., Papenberg, C., Pape, T., Berndt, C., Bohrmann, G., 2020. New insights into geology and geochemistry of the Kerch seep area in the Black Sea. Marine and Petroleum Geology 113, 104162.AbstractsAbraham, A., Mathew, A.K., Park, H., Choi, O., Sindhu, R., Parameswaran, B., Pandey, A., Park, J.H., Sang, B.-I., 2020. Pretreatment strategies for enhanced biogas production from lignocellulosic biomass. Bioresource Technology 301, 122725. inclusion of a pretreatment step in anaerobic digestion processes increases the digestibility of lignocellulosic biomass and enhances biogas yields by promoting lignin removal and the destruction of complex biomass structures. The increase in surface area enables the efficient interaction of microbes or enzymes, and a reduction in cellulose crystallinity improves the digestion process under anaerobic conditions. The pretreatment methods may vary based on the type of the lignocellulosic biomass, the nature of the subsequent process and the overall economics of the process. An improved biogas production by 1200% had been reported when ionic liquid used as pretreatment strategy for anaerobic digestion. The different pretreatment techniques used for lignocellulosic biomasses are generally grouped into physical, chemical, physicochemical, and biological methods. These four modes of pretreatment on lignocellulosic biomass and their impact on biogas production process is the major focus of this review article.Ado, M.R., 2020. Predictive capability of field scale kinetics for simulating toe-to-heel air injection heavy oil and bitumen upgrading and production technology. Journal of Petroleum Science and Engineering 187, 106843. by the International Energy Agency (IEA, 2018) showed that as the world's energy system is being decarbonised, the demand of fossil fuels, especially from the petrochemicals and transportation sectors which do not have any alternative, will continue to grow for the next two decades (i.e. to 2040). As a result, fully understood designs and operations of advanced technologies, such as the toe-to-heel air injection (THAI) heavy oil and bitumen upgrading and production process, are needed to develop the vast reserves of the virtually untapped bitumen/tar sand/heavy oil deposits. A new in-situ combustion type processes scaling procedure, which involved decreasing the reaction frequency factors, as proposed and detailed in Rabiu Ado (2017), was used to carry out a comparative study between the predictions by the two different types of validated kinetics schemes using computer modelling group (CMG) thermal reservoir simulator, the STARS. It is found that both models P and G, though each having different kinetics schemes and parameters, provided very similar qualitative predictions of the oil saturation and temperature profiles. However, model G was found to predict an unphysically high fuel concentration (206–330 kg m?3) at relatively low temperature (i.e. 165 to 252 ○C) at the base of the reservoir. This is not surprising since the field scale kinetics parameters for model G where not obtained in a systematic way, rather, they were obtained via trial and error. Additionally, model G's kinetics scheme is heavily dependent on the stoichiometric coefficient of the reaction's product. As a consequence, it is concluded that model P provided a more realistic prediction of the physicochemical processes, and hence, it should be used for future field studies.Ahn, S.H., Kim, K., Jo, N., Kang, J.J., Lee, J.H., Whitledge, T.E., Stockwell, D.A., Lee, H.W., Lee, S.H., 2020. Fluvial influence on the biochemical composition of particulate organic matter in the Laptev and Western East Siberian seas during 2015. Marine Environmental Research 155, 104873., we investigated the elemental (C/N ratio) and isotopic signatures (δ13C) and major biomolecules (carbohydrates, proteins, and lipids) and their relative abundance (i.e., the biochemical composition) in particulate organic matter (POM) to assess their origin and fate in the Laptev and western East Siberian seas during late summer/fall of 2015. In addition, we compared our results with the summer data of 2013 collected from Laptev and northwestern East Siberian seas. In accordance with the observed hydrological structure (i.e., a northward, warmer, diluted freshwater plume than previously observed in 2013), the more depleted δ13C (?28.2 ± 0.9‰) and higher C/N ratio (10.8 ± 2.0) than those of 2013 signalled that fluvially released terrestrial organic carbon (TerrOC) was the main source of the POM, unlike in 2013, when phytoplankton was the dominant source (δ13C = ?24.9 ± 1.0‰, C/N ratio = 7.6 ± 2.4; Ahn et al., 2019). During the offshore transport of heterogeneous TerrOC, carbohydrates seem to be the primary contributor to the bulk POM as a result of selective degradation and hydrodynamic sorting. Despite the TerrOC-dominated system in 2015, some marine influence was also found. The estimated phytoplankton biomass was low and comparable among the study sites. In addition, the presence of resting spores and high ammonium concentrations within the water column may suggest senescent and, to some extent, degrading conditions of the resident phytoplankton. In this regard, carbohydrate concentrations and freshwater content were significantly correlated (r = 0.79, p < 0.01), suggesting that carbohydrates are useful inferences of freshwater within overall study sites, at least when the marine influence is similar or low.Akhondzadeh, H., Keshavarz, A., Al-Yaseri, A.Z., Ali, M., Awan, F.U.R., Wang, X., Yang, Y., Iglauer, S., Lebedev, M., 2020. Pore-scale analysis of coal cleat network evolution through liquid nitrogen treatment: A Micro-Computed Tomography investigation. International Journal of Coal Geology 219, 103370. methane extraction suffers from low permeability, and liquid nitrogen treatment has been suggested as one of the methods to address this issue. This study thus investigates cryogenic liquid N2 fracturing of a bituminous coal at pore scale through 3D X-ray micro-computed tomography. The μ-CT results clearly demonstrate that freezing the coal with liquid nitrogen increases the porosity by over 11% and creates fracture planes with large apertures originating from the pre-existing cleats in the rock. The images also suggest connection establishment of the cleat network with originally isolated pores and micro-cleats following the freezing, thereby increasing pore network connectivity. Furthermore, SEM images of the frozen sample highlights the appearance of continuous wide conductive fractures with the maximum aperture size of 9?μm. The analysis of mechanical properties through Nano-indentation technique shows a decrease of up to 25% in the indentation modulus due to increase in the compressibility of the cracked rock. Moreover, as the main purpose of this fracturing treatment, the permeability evolution of the coal is examined computationally and experimentally. Lattice Boltzmann simulations on the μ-CT images highlight two-fold enhancement in permeability measure of the treated rock. Additionally, the outcome of core flooding tests shows 2.5 times increase in the permeability measure after liquid nitrogen exposure. This study thus provides a visual understanding of fracturing mechanism associated with liquid nitrogen treatment of a coal, and quantifies the pore structure and permeability evolution of the rock.Al Disi, Z.A., Bontognali, T.R.R., Jaoua, S., Attia, E., Al-Kuwari, H.A.S., Zouari, N., 2019. Influence of temperature, salinity and Mg2+:Ca2+ ratio on microbially-mediated formation of Mg-rich carbonates by Virgibacillus strains isolated from a sabkha environment. Scientific Reports 9, 19633. have demonstrated that microbes facilitate the incorporation of Mg2+ into carbonate minerals, leading to the formation of potential dolomite precursors. Most microbes that are capable of mediating Mg-rich carbonates have been isolated from evaporitic environments in which temperature and salinity are higher than those of average marine environments. However, how such physicochemical factors affect and concur with microbial activity influencing mineral precipitation remains poorly constrained. Here, we report the results of laboratory precipitation experiments using two mineral-forming Virgibacillus strains and one non-mineral-forming strain of Bacillus licheniformis, all isolated from the Dohat Faishakh sabkha in Qatar. They were grown under different combinations of temperature (20°, 30°, 40?°C), salinity (3.5, 7.5, 10 NaCl %w/v), and Mg2+:Ca2+ ratios (1:1, 6:1 and 12:1). Our results show that the incorporation of Mg2+ into the carbonate minerals is significantly affected by all of the three tested factors. With a Mg2+:Ca2+ ratio of 1, no Mg-rich carbonates formed during the experiments. With a Mg2+:Ca2+ ratios of 6 and 12, multivariate analysis indicates that temperature has the highest impact followed by salinity and Mg2+:Ca2+ ratio. The outcome of this study suggests that warm and saline environments are particularly favourable for microbially mediated formation of Mg-rich carbonates and provides new insight for interpreting ancient dolomite formations.Alexandrov, G.A., Brovkin, V.A., Kleinen, T., Yu, Z., 2020. The capacity of northern peatlands for long-term carbon sequestration. Biogeosciences 17, 47-54. peatlands have been a persistent natural carbon sink since the Last Glacial Maximum. The continued growth and expansion of these carbon-rich ecosystems could offset a large portion of anthropogenic carbon emissions before the end of the present interglacial period. Here we used an impeded drainage model and gridded data on the depth to bedrock and the fraction of histosol-type soils to evaluate the limits to the growth of northern peatland carbon stocks. Our results show that the potential carbon stock in northern peatlands could reach a total of 875±125?Pg?C before the end of the present interglacial, which could, as a result, remove 330±200?Pg?C of carbon from the atmosphere. We argue that northern peatlands, together with the oceans, will potentially play an important role in reducing the atmospheric carbon dioxide concentration over the next 5000 years.Ali, N., Zhang, Q., Liu, Z.-Y., Li, F.-L., Lu, M., Fang, X.-C., 2020. Emerging technologies for the pretreatment of lignocellulosic materials for bio-based products. Applied Microbiology and Biotechnology 104, 455-473. a cheap and clean renewable energy has become a common destination round the world with the depletion of oil resources and the concerns of increasing energy demands. Lignocellulosic biomass is the most abundant renewable resource in the biosphere, and the total biomass formed by plant photosynthesis reached more than 200 billion tons every year. Cellulase and hemicellulose and lignin degradation enzymes, the efficient biocatalyst, could efficiently convert the lignocellulosic biomass into sugars that could be further processed into biofuels, biochemical, and biomaterial for human requirement. The utilization and conversion of cellulosic biomass has great significance to solve the problems such as environmental pollution and energy crisis. Lignocellulosic materials are widely considered as important sources to produce sugar streams that can be fermented into ethanol and other organic chemicals. Pretreatment is a necessary step to overcome its intrinsic recalcitrant nature prior to the production of important biomaterial that has been investigated for nearly 200 years. Emerging research has focused in order of economical, eco-friendly, and time-effective solutions, for large-scale operational approach. These new mentioned technologies are promising for lignocellulosic biomass degradation in a huge scale biorefinery. This review article has briefly explained the emerging technologies especially the consolidated bioprocessing, chemistry, and physical base pretreatment and their importance in the valorization of lignocellulosic biomass conversion.Alili, A.S., Siddiquee, M.N., de Klerk, A., 2020. Origin of free radical persistence in asphaltenes: Cage effect and steric protection. Energy & Fuels 34, 348-359. petroleum fractions contain persistent free radicals, and the highest concentration of persistent free radicals is usually found in asphaltenes. The origin of free radical persistence was studied. The potential influence of exposure to air, free radical caging, and steric protection was evaluated. The free radical content of asphaltenes diluted in toluene remained constant to within 5% over a period of 465 h under both nitrogen and air atmospheres. The persistent free radicals were accessible for reaction in dilute solution. Caging of free radicals due to high viscosity could not explain the observations. Caging of free radicals due to molecular-level aggregation was possible, but explaining all of the observations in terms of the cage effect became tenuous. The asphaltenes appeared unencumbered by steric constraints compared to 9,10-dihydroanthracene during hydrogen transfer reactions, which made it unlikely that steric protection was a major contributor to the persistence of free radicals. The asphaltenes were reactive at 250 °C, both for self-reaction and for conversion of various model molecules (1,2-dihydronaphthalene, α-methylstyrene, 2,4,6-trimethylstyrene, 1,1-diphenylethylene, trans-1,2-diphenylethylene, triphenylethylene, tetraphenylethylene, and 9,10-dihydroanthracene). An alternative explanation for the origin of free radical persistence was forwarded. It was considered unlikely that individual free radical species could remain as persistent free radicals over geologic time but also be reactive. The observed persistence of free radicals could be explained in terms of a dynamic “equilibrium” of free radical pairs, which is a self-stabilizing process that gives the impression of free radical persistence. Dynamic formation and destruction of free radicals through addition and decomposition reactions of radical pairs average out on the macroscopic scale to create the impression of persistent free radicals. Any individual species does not remain persistent beyond what one would expect from a reactive persistent free radical.Alshareef, A.H., 2020. Asphaltenes: Definition, properties, and reactions of model compounds. Energy & Fuels 34, 16-30. simple definition of asphaltenes—the material that dissolves in aromatic solvents and precipitates in normal alkanes—proved to be not very defining at all. The nature of this material, how it formed, what its key properties are, and how it behaves under thermal or catalytic reaction conditions has extensively evolved over decades of continuous research and debate. One of the main sources of the debate was the apparent conflicting findings between numerous analytical studies and thermal reaction studies of asphaltenes and their model compounds. Similar to the blind men describing different parts of an elephant, many studies were describing some aspect of the material as it is observed but not realizing the existence of a “larger” object, and even the observations were very subjective to how asphaltenes were precipitated and analyzed and how data was generated and interpreted. In this paper, a brief summary is given on how asphaltenes are defined, how they form, and the current consensus on their properties, and finally a focus on thermal behavior, as observed from thermal studies on asphaltenes and their model compounds. The collective knowledge from analytical and thermal studies on the asphaltenes and various model compounds helped settle most of the debate on the notoriously complex material named asphaltenes.Amaral, M.S.S., Nolvachai, Y., Marriott, P.J., 2020. Comprehensive two-dimensional gas chromatography advances in technology and applications - biennial update. Analytical Chemistry 92, 85-104. from the pure methodological process of implementing a comprehensive two-dimensional gas chromatography (GC×GC) method, surely it is the excitement engendered by a well-designed separation that has captured the attention, fascinated and sustained proponents and users throughout the decades since Liu and Phillips1 were equally enthralled by what they produced, the first time they witnessed their result. This technology update largely addresses developments over the last 2 years (late 2017 – 2019) since the Synovec group presented their review.2 Progressive advances in instrumentation, software and data analysis tools, fundamental relationships and capabilities, and the numerous repertoire of applications to which GC×GC methods have been applied will be included. We attempt to offer an insight into the dynamic nature of the field, and hopefully many newer converts to the field will be recognized for their emerging interest and contributions.Ameen, C., Feuerborn, T.R., Brown, S.K., Linderholm, A., Hulme-Beaman, A., Lebrasseur, O., Sinding, M.-H.S., Lounsberry, Z.T., Lin, A.T., Appelt, M., Bachmann, L., Betts, M., Britton, K., Darwent, J., Dietz, R., Fredholm, M., Gopalakrishnan, S., Goriunova, O.I., Gr?nnow, B., Haile, J., Hallsson, J.H., Harrison, R., Heide-J?rgensen, M.P., Knecht, R., Losey, R.J., Masson-MacLean, E., McGovern, T.H., McManus-Fry, E., Meldgaard, M., Midtdal, ?., Moss, M.L., Nikitin, I.G., Nomokonova, T., Pálsdóttir, A.H., Perri, A., Popov, A.N., Rankin, L., Reuther, J.D., Sablin, M., Schmidt, A.L., Shirar, S., Smiarowski, K., Sonne, C., Stiner, M.C., Vasyukov, M., West, C.F., Ween, G.B., Wennerberg, S.E., Wiig, ?., Woollett, J., Dalén, L., Hansen, A.J., P. Gilbert, M.T., Sacks, B.N., Frantz, L., Larson, G., Dobney, K., Darwent, C.M., Evin, A., 2019. Specialized sledge dogs accompanied Inuit dispersal across the North American Arctic. Proceedings of the Royal Society B: Biological Sciences 286, 20191929.. 1929Domestic dogs have been central to life in the North American Arctic for millennia. The ancestors of the Inuit were the first to introduce the widespread usage of dog sledge transportation technology to the Americas, but whether the Inuit adopted local Palaeo-Inuit dogs or introduced a new dog population to the region remains unknown. To test these hypotheses, we generated mitochondrial DNA and geometric morphometric data of skull and dental elements from a total of 922 North American Arctic dogs and wolves spanning over 4500 years. Our analyses revealed that dogs from Inuit sites dating from 2000 BP possess morphological and genetic signatures that distinguish them from earlier Palaeo-Inuit dogs, and identified a novel mitochondrial clade in eastern Siberia and Alaska. The genetic legacy of these Inuit dogs survives today in modern Arctic sledge dogs despite phenotypic differences between archaeological and modern Arctic dogs. Together, our data reveal that Inuit dogs derive from a secondary pre-contact migration of dogs distinct from Palaeo-Inuit dogs, and probably aided the Inuit expansion across the North American Arctic beginning around 1000 BP.Ansari, A.H., Ahmad, S., Govil, P., Agrawal, S., Mathews, R.P., 2020. Mo-Ni and organic carbon isotope signatures of the mid-late Mesoproterozoic oxygenation. Journal of Asian Earth Sciences 191, 104201. study performed a redox sensitive trace element (RSTE) and organic carbon isotope investigation on the shallow section of ~1.2 Ga Bijaigarh Shale, Kaimur Group, Vindhyan Supergroup. The results demonstrate that unlike the coeval deeper section, in which Mo and Ni concentrations are several-folds higher compared to the upper continental crust (UCC), the shallow section contains Mo and Ni equivalent to the upper continental crust (UCC). This spatially heterogeneous burial of Mo and Ni is very similar to the modern stratified basins i.e., Black Sea and Cariaco Basin, where Ni and Mo composition of the sediments underlying a shallow oxic water column is comparable to the UCC however, the deeper sediments underlying the anoxic/euxinic contains several folds-higher Mo and Ni compared to the UCC. Bulk precipitation of Mo in a hydrosphere is mainly controlled by sulphide present in the anoxic/euxinic layers of the water column, on the other hand, Ni precipitation is generally controlled by oxygenic primary productivity. Though the shallow section of the Bijaigarh Shale is depleted in Ni, a significant correlation between Ni and TOC is still relevant and indicates an oxygen-rich surface water layer for the respective palaeohydrosphere. Furthermore, δ13C-org values (between ?32.0 and ?30.4‰) from the shallow section suggests that the organic carbon exported into the sediments during the Bijaigarh Shale deposition was primarily derived from oxygenic photosynthesis in the concurrent surface water layers.Aparecida Silva Almeida, C., Regina Baggio, S., Regina Barros Mariutti, L., Bragagnolo, N., 2020. One-step rapid extraction of phytosterols from vegetable oils. Food Research International 130, 108891. conditions for the extraction of phytosterols (campesterol, stigmasterol and β-sitosterol) from vegetal oils were optimized by means of response surface methodology (RSM). A 24 central composite rotatable design (CCRD) was used to investigate the effects of four independent variables: sample weight (g), saponification temperature (oC), saponification time (h) and number of extractions (n). The CCRD was carried out in 27 trials, including eight axial and three central points; and the response variables were the contents of campesterol, stigmasterol, β-sitosterol and total phytosterols. The optimized conditions established by the RSM were 0.3 g of sample, saponification for 3 h at 50 °C and 4 extractions with n-hexane. Satisfactory values for linearity, recovery, repeatability, accuracy, precision, limits of detection (2.0-2.3 mg/100g) and quantification (6.5-7.7 mg/100g) were achieved. The optimized method was also validated by comparison with the official AOCS method, and the contents of stigmasterol and β-sitosterol did not show significant differences (p>0.05) when determined by both methods. However, low values (p<0.05) for campesterol were found when the samples were analyzed by the AOCS method. The method optimized and validated in the present work is easy to carry out, fast and accurate. The method was successfully applied to sunflower, canola, corn, soybean and olive oils, and the lowest contents of total phytosterols were found in olive oil while and the highest amounts, in corn oil.Archer, S.D.J., Pointing, S.B., 2020. Anthropogenic impact on the atmospheric microbiome. Nature Microbiology 5, 229-231. atmosphere has undergone extensive physico-chemical change due to anthropogenic emissions. The impact on the ecology of the atmospheric microbiome has so far not been considered. Here, we define the scope of change to the atmosphere and identify potential microbial responses.Arevalo Jr, R., Ni, Z., Danell, R.M., 2020. Mass spectrometry and planetary exploration: A brief review and future projection. Journal of Mass Spectrometry 55, e4454. the inception of mass spectrometry more than a century ago, the field has matured as analytical capabilities have progressed, instrument configurations multiplied, and applications proliferated. Modern systems are able to characterize volatile and nonvolatile sample materials, quantitatively measure abundances of molecular and elemental species with low limits of detection, and determine isotopic compositions with high degrees of precision and accuracy. Consequently, mass spectrometers have a rich history and promising future in planetary exploration. Here, we provide a short review on the development of mass analyzers and supporting subsystems (eg, ionization sources and detector assemblies) that have significant heritage in spaceflight applications, and we introduce a selection of emerging technologies that may enable new and/or augmented mission concepts in the coming decades.Arif, M., Bai, Y., Usman, M., Jalalah, M., Harraz, F.A., Al-Assiri, M.S., Li, X., Salama, E.-S., Zhang, C., 2020. Highest accumulated microalgal lipids (polar and non-polar) for biodiesel production with advanced wastewater treatment: Role of lipidomics. Bioresource Technology 298, 122299. lipids consist of non-polar and polar lipids. Triacyleglyceride (TAG), a non-polar lipid, is convertible to biodiesel, whereas glycolipids and phospholipids are polar and not convertible to biodiesel lowing to their high degree of unsaturation (polyunsaturated fatty acids), which makes the production process insufficient and expensive. In this review, microalgal species that contain the highest lipid content (≥40%) in the literature till 2019 are highlighted. The differentiation between non-polar and polar lipids and the limitations in the conversion of polar lipids to biodiesel are reported. The basic and advanced factors contributing to the accumulation of lipids convertible to biodiesel is discussed. Microalgal species including Scenedesmus obliquus, Ourococcus multisporus, Chlamydomonas pitschmannii, Micractinium reisseri, and Botryococcus braunii with high lipid content are potential candidates for biomass/biodiesel production and nutrient removal from wastewater. Application of lipidomics and transcriptomics to manipulate the lipid associated gene acetyl-CoA synthetase in microalgae improves the accumulative lipid content.Arif, S., Reitner, J., Hoppert, M., 2019. Composition, diversity and functional analysis of the modern microbiome of the Middle Triassic Cava superiore beds (Monte San Giorgio, Switzerland). Scientific Reports 9, 20394. laminated shales and limestones from the Monte San Giorgio (Lugano Prealps, Switzerland) are known as famous fossil lagerst?tten for excellently preserved fossils from the Middle Triassic Period. The various bituminous shales from Monte San Giorgio are thermally immature and rich in diverse organic compounds, which provide unique substrates for active soil microbial communities. We selected the Cava superior beds of the Acqua del Ghiffo site for?this study. To investigate its microbial structure and diversity, contig assembly, Operational Taxonomic Units (OTUs) clustering, and rarefaction analysis were performed for bacterial 16S?rDNA preparations?from?bituminous and non-bituminous limestone strata with the MetaAmp pipeline. Principal coordinates analysis shows that the microbial communities from the bituminous strata differ significantly from limestone samples (P?<?0.05 Unifrac weighted). Moreover, metagenomic tools could also be used effectively to analyze the microbial communities shift during enrichment in specific growth media. In the nutrient-rich media, one or few taxa, mainly Proteobacteria and Firmicutes, were enriched which led to the drastic diversity loss while oligotrophic media could enrich many taxa simultaneously and sustain the richness and diversity of the inoculum. Piphillin, METAGENassist and MicrobiomeAnalyst pipeline also predicted that the Monte San Giorgio bituminous shales and oligotrophic enriched microbiomes degrade complex polycyclic aromatic hydrocarbons.Ash, J.L., Hu, H., Yeung, L.Y., 2020. What fractionates oxygen isotopes during respiration? Insights from multiple isotopologue measurements and theory. ACS Earth and Space Chemistry 4, 50-66. precise mass dependence of respiratory O2 consumption underpins the “oxygen triple-isotope” approach to quantifying gross primary productivity in modern and ancient environments. Yet, the physical-chemical origins of the key 18O/16O and 17O/16O covariations observed during respiration have not been tied to theory; thus, the approach remains empirical. First-principles calculations on enzyme active-site models suggest that changes in the O–O bond strength upon electron transfer strongly influence respiratory isotopic fractionation. However, molecular diffusion may also be important. Here, we use measurements of the relative abundances of rare isotopologues 17O18O and 18O18O as additional tracers of mass dependence during dark respiration experiments of lacustrine water. We then compare the experimental results to first-principles calculations of O2 interacting with heme-oxidase analogues. We find a significantly steeper mass dependence, supported by theory, than has been previously observed. Enrichments of 17O18O and 18O18O in the O2 residue suggest that θ values are strongly influenced by chemical processes, rather than being dominated by physical processes (i.e., by bond alteration rather than diffusion). In contrast, earlier data are inconsistent with theory, implying that analytical artifacts may have biased those results. Implications for quantifying primary productivity are discussed.Attias, E., Amalokwu, K., Watts, M., Falcon-Suarez, I.H., North, L., Hu, G.W., Best, A.I., Weitemeyer, K., Minshull, T.A., 2020. Gas hydrate quantification at a pockmark offshore Norway from joint effective medium modelling of resistivity and seismic velocity. Marine and Petroleum Geology 113, 104151. emissions from gas hydrate deposits along continental margins may alter the biogeophysical properties of marine environments, both on local and regional scales. The saturation of a gas hydrate deposit is commonly calculated using the elastic or electrical properties measured remotely or in-situ at the site of interest. Here, we used a combination of controlled-source electromagnetic (CSEM), seismic and sediment core data obtained in the Nyegga region, offshore Norway, in a joint elastic-electrical approach to quantify marine gas hydrates found within the CNE03 pockmark. Multiscale analysis of two sediment cores reveals significant differences between the CNE03 pockmark and a reference site located approximately 150?m northwest of CNE03. Gas hydrates and chemosynthetic bivalves were observed in the CNE03 sediments collected. The seismic velocity and electrical resistivity measured in the CNE03 sediment core are consistent with the P-wave velocity (VP) and resistivity values derived from seismic and CSEM remote sensing datasets, respectively. The VP gradually increases (~1.75–1.9?km/s) with depth within the CNE03 pipe-like structure, whereas the resistivity anomaly remains ~3?Ωm. A joint interpretation of the collocated seismic and CSEM data using a joint elastic-electrical effective medium model suggests that for the porosity range 0.55–0.65, the gas hydrate saturation within the CNE03 hydrate stability zone varies with depth between ~20 and 48%. At 0.6 porosity, the hydrate saturation within CNE03 varies between ~23 and 37%, whereas the weighted mean saturation is ~30%. Our results demonstrate that a well-constrained gas hydrate quantification can be accomplished by coupling P-wave velocity and CSEM resistivity data through joint elastic-electrical effective medium modelling. The approach applied in this study can be used as a framework to quantify hydrate in various marine sediments.Azevedo, V., Stríkis, N.M., Santos, R.A., de Souza, J.G., Ampuero, A., Cruz, F.W., de Oliveira, P., Iriarte, J., Stumpf, C.F., Vuille, M., Mendes, V.R., Cheng, H., Edwards, R.L., 2019. Medieval climate variability in the eastern Amazon-Cerrado regions and its archeological implications. Scientific Reports 9, 20306. South American Monsoon System is responsible for the majority of precipitation in the continent, especially over the Amazon and the tropical savannah, known as ‘Cerrado’. Compared to the extensively studied subtropical and temperate regions the effect of the Medieval Climate Anomaly (MCA) on the precipitation over the tropics is still poorly understood. Here, we present a multiproxy paleoprecipitation reconstruction showing a consistent change in the hydrologic regime during the MCA in the eastern Amazon and ‘Cerrado’, characterized by a substantial transition from humid to drier conditions during the Early (925-1150?C.E.) to Late-MCA (1150-1350?C.E.). We compare the timing of major changes in the monsoon precipitation with the expansion and abandonment of settlements reported in the archeological record. Our results show that important cultural successions in the?pre-Columbian Central Amazon, the transition from Pared?o to Guarita phase, are in agreement with major changes in the hydrologic regime. Phases of expansion and, subsequent abandonment, of large settlements from Pared?o during the Early to Late-MCA are coherent with a?reduction in water supply. In this context we argue that the sustained drier conditions during the latter period may have triggered territorial disputes with Guarita leading to the Pared?o demise.Babadagli, T., 2020. Philosophy of EOR. Journal of Petroleum Science and Engineering 188, 106930. paper seeks answers, through a ‘philosophical’ approach, to the questions of whether enhanced oil recovery projects are purely driven by economic restrictions (i.e. oil prices) or if there are still technical issues to be considered, making companies refrain from enhanced oil recovery (EOR) applications. Another way of approaching these questions is to ask why some EOR projects are successful and long-lasting regardless of substantial fluctuations in oil prices. To find solid answers to these two, by ‘philosophical’ reasoning, further questions were raised including: (1) has sufficient attention been given to the ‘cheapest’ EOR methods such as air and microbial injection, (2) why are we afraid of the most expensive miscible processes that yield high recoveries in the long run, or (3) why is the incubation period (research to field) of EOR projects so lengthy? After a detailed analysis using sustainable EOR example cases both answers to these questions and supportive data were sought.Premises were listed as outcomes to be considered in the decision making and development of EOR projects. Examples of said considerations include: (1) Every EOR process is case-specific and analogies are difficult to make, hence we still need serious efforts for project design and research for specific processes and technologies, (2) discontinuity in fundamental and case-specific research has been one of the essential reasons preventing the continuity of the projects rather than drops in oil prices, and (3) any EOR project can be made economical, if technical success is proven, through proper optimization methods and continuous project monitoring whilst considering the minimal profit that the company can tolerate.Finally, through the ‘philosophical’ approach and using worldwide successful EOR cases, the following three parameters were found to be the most important factors in running successful EOR applications, regardless of oil prices and risky investment costs, to extend the life span of the reservoir and warrant both short and long-term profit: (1) Proper technical design and implementation of the selected EOR method through continuous monitoring and re-engineering the project (how to apply more than what to apply), (2) good reservoir characterization and geological descriptions and their effect on the mechanics of the EOR process, and (3) paying attention to experience and expertise (human factor).It is believed that the systematic analysis and philosophical approach followed in this paper and the outcome will provide proper guidance to EOR projects for upcoming decades.Bailey, S.E., Kupczik, K., Hublin, J.-J., Antón, S.C., 2020. Reply to Scott et al: A closer look at the 3-rooted lower second molar of an archaic human from Xiahe. Proceedings of the National Academy of Sciences 117, 39. et al. (1) take issue with our claim (2) that the presence of a 3-rooted lower molar (3RLM) in the Xiahe mandible (3) provides a morphological link between Denisovans and recent Asians. Below we address their main points:1) Scott et al. (1) claim that our assessment is based on the “wrong” tooth. While it is true that the 3RLM is rare on M2, regardless of the tooth position, the 3RLM is strongly linked to Asia. At least one clinical study found the 3RLM on the M2 to be 60% more frequent (2.8% vs. 1.7%) in Asian vs. non-Asian populations (4). Moreover, even if M1 is the “key” tooth for the 3RLM, it does not follow that its … Original Article: Bailey, S.E., Hublin, J.-J., Antón, S.C., 2019. Rare dental trait provides morphological evidence of archaic introgression in Asian fossil record, PNAS 116 (30) 14806-ment by: Scott, G.R., Irish, J.D., Martinón-Torres, M., 2020. A more comprehensive view of the Denisovan 3-rooted lower second molar from Xiahe. Proceedings of the National Academy of Sciences 117, 37.Bajerski, F., Bürger, A., Glasmacher, B., Keller, E.R.J., Müller, K., Mühldorfer, K., Nagel, M., Rüdel, H., Müller, T., Schenkel, J., Overmann, J., 2020. Factors determining microbial colonization of liquid nitrogen storage tanks used for archiving biological samples. Applied Microbiology and Biotechnology 104, 131-144. availability of bioresources is a precondition for life science research, medical applications, and diagnostics, but requires a dedicated quality management to guarantee reliable and safe storage. Anecdotal reports of bacterial isolates and sample contamination indicate that organisms may persist in liquid nitrogen (LN) storage tanks. To evaluate the safety status of cryocollections, we systematically screened organisms in the LN phase and in ice layers covering inner surfaces of storage tanks maintained in different biobanking facilities. We applied a culture-independent approach combining cell detection by epifluorescence microscopy with the amplification of group-specific marker genes and high-throughput sequencing of bacterial ribosomal genes. In the LN phase, neither cells nor bacterial 16S rRNA gene copy numbers were detectable (detection limit, 102 cells per ml, 103 gene copies per ml). In several cases, small numbers of bacteria of up to 104 cells per ml and up to 106 gene copies per ml, as well as Mycoplasma, or fungi were detected in the ice phase formed underneath the lids or accumulated at the bottom. The bacteria most likely originated from the stored materials themselves (Elizabethingia, Janthibacterium), the technical environment (Pseudomonas, Acinetobacter, Methylobacterium), or the human microbiome (Bacteroides, Streptococcus, Staphylococcus). In single cases, bacteria, Mycoplasma, fungi, and human cells were detected in the?debris at the bottom of the storage tanks. In conclusion, the limited microbial load of the ice phase and in the debris of storage tanks can be effectively avoided by minimizing ice formation and by employing hermetically sealed sample containers.Baker, S.J., Belcher, C.M., Barclay, R.S., Hesselbo, S.P., Laurin, J., Sageman, B.B., 2019. CO2-induced climate forcing on the fire record during the initiation of Cretaceous oceanic anoxic event 2. GSA Bulletin 132, 321-333. oceanic anoxic event 2 (OAE2) is thought to have been contemporary with extensive volcanism and the release of large quantities of volcanic CO2 capable of triggering marine anoxia through a series of biogeochemical feedbacks. High-resolution reconstructions of atmospheric CO2 concentrations across the initiation of OAE2 suggest that there were also two distinct pulses of CO2 drawdown coeval with increased organic carbon burial. These fluctuations in CO2 likely led to significant climatic changes, including fluctuations in temperatures and the hydrological cycle. Paleofire proxy records suggest that wildfire was a common occurrence throughout the Cretaceous Period, likely fueled by the estimated high atmospheric O2 concentrations at this time. However, over geological time scales, the likelihood and behavior of fire are also controlled by other factors such as climate, implying that CO2-driven climate changes should also be observable in the fossil charcoal record.We tested this hypothesis and present a high-resolution study of fire history through the use of fossil charcoal abundances across the OAE2 onset, and we compared our records to the estimated CO2 fluctuations published from the same study sites. Our study illustrates that inferred wildfire activity appears to relate to changes in CO2 occurring across the onset of OAE2, where periods of CO2 drawdown may have enabled an increase in fire activity through suppression of the hydrological cycle. Our study provides further insight into the relationships between rapid changes in the carbon cycle, climate, and wildfire activity, illustrating that CO2 and climate changes related to inferred wildfire activity can be detected despite the estimated high Cretaceous atmospheric O2 concentrations.Balfourier, A., Luciani, N., Wang, G., Lelong, G., Ersen, O., Khelfa, A., Alloyeau, D., Gazeau, F., Carn, F., 2020. Unexpected intracellular biodegradation and recrystallization of gold nanoparticles. Proceedings of the National Academy of Sciences 117, 103-113.: While gold nanoparticles are at the core of an increasing range of medical applications, their fate in the organism has barely been studied so far. Because of their chemical inertness, common belief is that gold nanoparticles remain endlessly intact in tissues. We show that 4- to 22-nm gold nanoparticles are actually degraded in vitro by cells, with a faster degradation of the smallest size. Transcriptomics studies reveal the active role of cell lysosome into this biodissolution. Furthermore, we point out that the released gold recrystallizes into biopersistent nanostructures. Interestingly, these degradation products are similar to previously observed gold deposits in human tissues after gold salts treatment for rheumatoid arthritis, underlying a common metabolism between gold nanoparticles and ionic gold.Abstract: Gold nanoparticles are used in an expanding spectrum of biomedical applications. However, little is known about their long-term fate in the organism as it is generally admitted that the inertness of gold nanoparticles prevents their biodegradation. In this work, the biotransformations of gold nanoparticles captured by primary fibroblasts were monitored during up to 6 mo. The combination of electron microscopy imaging and transcriptomics study reveals an unexpected 2-step process of biotransformation. First, there is the degradation of gold nanoparticles, with faster disappearance of the smallest size. This degradation is mediated by NADPH oxidase that produces highly oxidizing reactive oxygen species in the lysosome combined with a cell-protective expression of the nuclear factor, erythroid 2. Second, a gold recrystallization process generates biomineralized nanostructures consisting of 2.5-nm crystalline particles self-assembled into nanoleaves. Metallothioneins are strongly suspected to participate in buildings blocks biomineralization that self-assembles in a process that could be affected by a chelating agent. These degradation products are similar to aurosomes structures revealed 50 y ago in vivo after gold salt therapy. Overall, we bring to light steps in the lifecycle of gold nanoparticles in which cellular pathways are partially shared with ionic gold, revealing a common gold metabolism.Balseiro, D., Powell, M.G., 2019. Carbonate collapse and the late Paleozoic ice age marine biodiversity crisis. Geology 48, 118-122. late Paleozoic ice age (LPIA) was characterized by persistently low diversity of marine invertebrates following a second-order mass extinction. Here, we used a data set of North American (paleotropical) fossil occurrences of brachiopod, bivalve, and coral genera from the Paleobiology Database, combined with lithologic data from Macrostrat, to demonstrate that low diversity was caused by the collapse of carbonate environments during the LPIA. After dividing the data by lithology, low diversity was evident only in carbonate environments, whereas diversity within siliciclastic environments actually increased during the LPIA, after a brief decline in the Serpukhovian (late Mississippian). Diversity patterns closely matched respective changes in the volume of carbonate and siliciclastic rocks. The contrasting patterns observed in the two environments suggest that habitat loss was a direct cause of changes in diversity, because other factors, such as temperature, would have affected genera in both environments. A causal relationship is also supported by the finding that diversity remained high in carbonate refugia (carbonate beds within majority-siliciclastic formations) until the Bashkirian, postdating the onset of icehouse conditions by ～8 m.y. Our results provide a unifying, mechanistic explanation for the distinctive characteristics of the biotic impact, including its disproportionate effect on the tropical marine invertebrate fauna, prolonged recovery from extinction, low macroevolutionary rates during the recovery interval, and regional differences in its expression.Banda, J.F., Lu, Y., Hao, C., Pei, L., Du, Z., Zhang, Y., Wei, P., Dong, H., 2020. The effects of salinity and pH on microbial community diversity and distribution pattern in the brines of soda lakes in Badain Jaran Desert, China. Geomicrobiology Journal 37, 1-12. Badain Jaran Desert (BJD) is characterized by extremely arid conditions. Counterintuitively, this arid region has over 100 permanent lakes. To date, only a few studies have characterized microbial community in these lakes. Our investigation sampled five lakes with salinity (2.1?397.33 g/L) and pH (9.69?10.83) gradients, of which one was low salinity (< 3.0 g/L), three were moderately saline (50?250 g/L) and the other one was hypersaline (>250.0 g/L). Using high-throughput sequencing of 16S rRNA genes, we noted a significant difference in microbial communities inhabiting the different alkali-saline lakes. Generally, bacteria were predominant in the low and moderately saline lakes, while archaea were dominant in the hypersaline lake. The low salinity lake exhibited the highest microbial diversity, dominated by Burkholderia and Halomonas. Spiribacter and Halomonas dominated the moderately saline lakes, while Halohasta and Halosimplex dominated the hypersaline lake. pH was a primary driver of microbial richness, whereas salinity was the predominant factor controlling microbial community composition. Therefore, both pH and salinity shaped the haloalkaliphilic community in the soda lakes. Furthermore, it was found that many haloalkaliphiles such as Spiribacter and Halomonas survived beyond their pH and salinity limits, suggesting that there could be more new species in these soda lakes.Bang, S., Lee, Y.I., 2020. Darriwilian carbon isotope stratigraphy in the Taebaeksan Basin, Korea and its implications for Middle Ordovician paleoceanography. Palaeogeography, Palaeoclimatology, Palaeoecology 541, 109534. middle Darriwilian carbon isotope excursion (MDICE) event is first documented from central eastern Korea (Taebaeksan Basin), the eastern part of the Sino-Korean Block, and is well correlated with global carbon isotope chemostratigraphy. The Korean MDICE record shows three broad positive peaks and complements records from the Middle Ordovician peri-Gondwanan epeiric seas showing incomplete records due to disconformity. This study reconstructed paleoceanographic conditions with nitrogen isotopic compositions and clay mineral compositions to understand the causes of carbon isotope excursions. The heavier excursion in nitrogen isotopic curve and abrupt increase of kaolinite in the early MDICE interval are interpreted as a result of epeiric sea denitrification associated with strong seawater stratification, and the main cause of those conditions was likely increased precipitation in the adjacent land. Subsequent sea-level rise caused an anti-estuarine circulation in the Taebaeksan sea and increased the organic carbon burial in the adjacent basin setting, which might have sustained the MDICE. The documentation of the MDICE event in this study supports the view that the MDICE occurred globally. This study provides not only information on the regional paleoceanographic conditions that occurred in the Middle Ordovician epeiric seas during the course of MDICE, but also reports that the MDICE event occurred as a response to seawater circulation associated with global sea-level rising in the Middle Ordovician.Barco, R.A., Garrity, G.M., Scott, J.J., Amend, J.P., Nealson, K.H., Emerson, D., 2020. A genus definition for Bacteria and Archaea based on a standard genome relatedness index. mBio 11, e02475-19.: Genus assignment is fundamental in the characterization of microbes, yet there is currently no unambiguous way to demarcate genera solely using standard genomic relatedness indices. Here, we propose an approach to demarcate genera that relies on the combined use of the average nucleotide identity, genome alignment fraction, and the distinction between type- and non-type species. More than 3,500 genomes representing type strains of species from >850 genera of either bacterial or archaeal lineages were tested. Over 140 genera were analyzed in detail within the taxonomic context of order/family. Significant genomic differences between members of a genus and type species of other genera in the same order/family were conserved in 94% of the cases. Nearly 90% (92% if polyphyletic genera are excluded) of the type strains were classified in agreement with current taxonomy. The 448 type strains that need reclassification directly impact 33% of the genera analyzed in detail. The results provide a first line of evidence that the combination of genomic indices provides added resolution to effectively demarcate genera within the taxonomic framework that is currently based on the 16S rRNA gene. We also identify the emergence of natural breakpoints at the genome level that can further help in the circumscription of taxa, increasing the proportion of directly impacted genera to at least 43% and pointing at inaccuracies on the use of the 16S rRNA gene as a taxonomic marker, despite its precision. Altogether, these results suggest that genomic coherence is an emergent property of genera in Bacteria and Archaea.Importance: In recent decades, the taxonomy of Bacteria and Archaea, and therefore genus designation, has been largely based on the use of a single ribosomal gene, the 16S rRNA gene, as a taxonomic marker. We propose an approach to delineate genera that excludes the direct use of the 16S rRNA gene and focuses on a standard genome relatedness index, the average nucleotide identity. Our findings are of importance to the microbiology community because the emergent properties of Bacteria and Archaea that are identified in this study will help assign genera with higher taxonomic resolution.Bargar, T.A., Stout, S.A., Alvarez, D., 2020. Petroleum hydrocarbons in semipermeable membrane devices deployed in the Northern Gulf of Mexico and Florida keys following the Deepwater Horizon incident. Marine Pollution Bulletin 150, 110622. Deepwater Horizon (DWH) oil spill from April to July of 2010 contaminated Gulf of Mexico waters through release of an estimated 4.1?×?106 barrels of oil. Beginning in June of 2010, semipermeable membrane devices (SPMDs) were deployed near areas with sensitive marine habitats (Alabama Alps and Western Shelf) potentially exposed to that oil. Elevated TPAH50 concentrations, flux rates and similarity of histograms and diagnostic ratios for polycyclic aromatic hydrocarbons (PAH) from SPMDs to weathered floating oil collected during the DWH spill indicates the Alabama Alps habitats were affected. While not affected by oil from the DWH spill, the temporal pattern of PAH contamination of SPMDs deployed near the Western Shelf between July 2010 and March 2011 could indicate prevailing currents affected contaminant transport to the Western Shelf Area (East and West Flower Garden, Sonnier, and Stetson Banks) from non-DWH sources, including oil and gas exploration, shipping, and Mississippi River effluent.Baroni, I.R., Palastanga, V., Slomp, C.P., 2020. Enhanced organic carbon burial in sediments of oxygen minimum zones upon ocean deoxygenation. Frontiers in Marine Science 6, 839. doi: 10.3389/fmars.2019. 00839. minimum zones (OMZs) in the ocean are expanding. This expansion is attributed to global warming and may continue over the next 10 to 100 kyrs due to multiple climate CO2-driven factors. The expansion of oxygen-deficient waters has the potential to enhance organic carbon burial in marine sediments, thereby providing a negative feedback on global warming. Here, we study the response of dissolved oxygen in the ocean to increased phosphorus and iron inputs due to CO2-driven enhanced weathering and increased dust emissions, respectively. We use an ocean biogeochemical model coupled to a general ocean circulation model (the Hamburg Oceanic Carbon Cycle model, HAMOCC 2.0) to assess the impact of such regional deoxygenation on organic carbon burial in the modern ocean on time scales of up to 200 kyrs. We find that an increase in input of phosphorus and iron leads to an expansion of the area of the OMZ impinging on continental margin sediments and a significant decline in bottom water oxygen in the open ocean relative to pre-industrial conditions. The associated increase in organic carbon burial could contribute to the drawdown of ~1,600 Gt of carbon, which is equivalent to the total amount of CO2 in the atmosphere predicted for the year 2100 in a business as usual scenario, on time scales of up to 50 kyrs. The corresponding areal extent of sediments overlain by bottom waters with little or no oxygen as estimated by the model is not very different from the minimum area estimated for two major oceanic anoxic events in Earth's past. Such events were associated with major perturbations of the oceanic carbon cycle, including high rates of organic carbon burial. We conclude that organic carbon burial in low oxygen areas in the ocean could contribute to removal of anthropogenic CO2 from the atmosphere on long time scales.Bartelink, E.J., Beasley, M.M., Eerkens, J.W., Gardner, K.S., Wiberg, R.S., Garibay, R., 2020. Stable isotope evidence of diet breadth expansion and regional dietary variation among Middle-to-Late Holocene Hunter-Gatherers of Central California. Journal of Archaeological Science: Reports 29, 102182. stable isotope research on Middle-to-Late Holocene (6600 cal BP-present) hunter-gatherers of Central California has documented significant regional variation in human paleodiets between the San Francisco Bay Area and Central Valley. In general, this geographically-patterned dietary variation tracks greater consumption of marine food resources in the Bay Area and greater consumption of freshwater and terrestrial food resources in the Central Valley. Using stable carbon and nitrogen isotope analysis of bone collagen, stable carbon isotopes of bone bioapatite, and a large series of AMS dates (5420-2975 cal BP), we examine human paleodiets in 238 burials from CA-CCO-548 (Marsh Creek), located near the Sacramento-San Joaquin Delta, in Central California. Isotopic results support archaeofaunal and paleobotanical findings regarding the dietary importance of terrestrial C3-resources (e.g., artiodactyls, small seeds, acorns) and freshwater fish. The results further indicate that marine resources were of minor importance and could have been acquired from brackish areas near the mouth of the San Francisco Bay estuary located 9?km away or through trade. Although carbon and nitrogen isotopes of bone collagen suggest continuity in the sources of dietary protein over time. Carbon isotopes of bone bioapatite demonstrate a significant temporal shift toward greater consumption of C3 plant resources, such as acorns and small seeds, consistent with resource intensification models. The paleodiet of the CA-CCO-548 population is similar to contemporaneous groups located to the south and northwest, but is distinct from groups within the Delta and San Francisco Bay Area.Basilio, E., Babadagli, T., 2020. Use of air with methane in cyclic solvent injection applications for improved foam stability and cost effective heavy oil recovery. Energy & Fuels 34, 278-293. oil flow is commonly encountered in heavy oil production from homogeneous or heterogeneous (after cold heavy oil production with sands—CHOPS) reservoirs. This can be due to a drive mechanism in the primary production (depletion of methane saturated heavy-oil) and secondary stage (gas injection after primary production). In the primary stage, among other important parameters, the pressure depletion rate has been reported to be the most critical characteristic to control this type of flow. In the secondary stage, gas amount and type (sole injection of methane, carbon dioxide, propane, or a combination of these), and application conditions (soaking time on cyclic solvent injection (CSI) durations, depletion rate) are critical. The cornerstone of the foamy oil behavior during CSI relies on its stability, of which depends on parameters such as oil viscosity, temperature, dissolved gas ratio, pressure decline rate, and dissolved gas (solvent) composition. Although the process has been investigated and analyzed for different parameters in the literature, the optimal conditions for an effective and more economical process (mainly foamy oil stability) has not been thoroughly understood, especially for secondary recovery conditions. In this study, air has been used as an ameliorative to improve foamy oil stability during CSI. Four pressure depletion tests were performed, each of them consisting of five consecutive cycles. Each pressure depletion test included eight independent pressure recordings obtained from pressure transducers distributed along a sandpack holder for 48 hours. In order to reach the optimal conditions of the applications, three different pressure depletion rates were tested at 0.23 psi, 0.51 psi/min, 1.53 psi/min, together with air as an ameliorative for foamy oil stability. We observed that increasing pressure depletion rates increased the formation of foamy oil, however, when pressure depletion rates were too high, it may have caused a negative effect in the final oil recovery factor by CSI. Injecting air into the sandpack caused an increase in the viscosity of heavy oil, and the subsequent injection of methane as a solvent became more effective in generating more stable foamy oil, which resulted in obtaining a higher oil recovery factor. Bastviken, D., Nygren, J., Schenk, J., Parellada Massana, R., Duc, N.T., 2020. Technical note: Facilitating the use of low-cost methane (CH4) sensors in flux chambers – calibration, data processing, and an open source make-it-yourself logger. Biogeosciences Discussions 2020, 1-16. major bottleneck regarding the efforts to better quantify greenhouse gas fluxes, map sources and sinks, and understand flux regulation, is the shortage of low-cost and accurate-enough measurement methods. The studies of methane (CH4) – a long-lived greenhouse gas increasing rapidly but irregularly in the atmosphere for unclear reasons, and with poorly understood source-sink attribution – suffer from such method limitations. This study present new calibration and data processing approaches for use of a low-cost CH4 sensor in flux chambers. Results show that the change in relative CH4 levels can be determined at rather high accuracy in the 2–700?ppm range, with modest efforts of collecting reference samples in situ, and without continuous access to expensive reference instruments. These results open for more affordable and time-effective measurements of CH4 in flux chambers. To facilitate such measurements, we also provide a description for building and using an Arduino logger for CH4, carbon dioxide (CO2), humidity, and temperature.Baú, J.P.T., Villafa?e-Barajas, S.A., da Costa, A.C.S., Negrón-Mendoza, A., Colín-Garcia, M., Zaia, D.A.M., 2019. Adenine adsorbed onto montmorillonite exposed to ionizing radiation: Essays on prebiotic chemistry. Astrobiology 20, 26-38. adsorption and radiolysis experiments related to prebiotic chemistry studies are performed in distilled water or sodium chloride solutions. However, distilled water and sodium chloride solutions do not represent the composition of the primitive seas of Earth. In this work, an artificial seawater with ion abundances Mg2+ > Ca2+ >> Na+ ≈ K+ and SO42? >> Cl? was used, one that is different from the average composition of seawater today. This artificial seawater is named seawater 4.0 Ga, since it better represents the composition of the major constituents of seawater of primitive Earth. The radiolysis of adenine adsorbed onto montmorillonite was studied. The most important result is that adenine is adsorbed onto montmorillonite, when it is dissolved in artificial seawater 4.0 Ga, and the clay protects adenine against gamma radiation decomposition. However, desorption of adenine from montmorillonite was possible only with 0.10?mol L?1 of KOH. This result indicates that adenine was strongly bonded to montmorillonite. Fourier transform infrared spectroscopy showed that NH2 group and electrostatic interactions, between negatively charged montmorillonite and positively charged adenine, are responsible for adsorption of adenine onto montmorillonite. In addition, X-ray diffractograms showed that adenine enters in the interlayer space of montmorillonite. Baumgartner, R.J., Van Kranendonk, M.J., Pagès, A., Fiorentini, M.L., Wacey, D., Ryan, C., 2020. Accumulation of transition metals and metalloids in sulfidized stromatolites of the 3.48 billion–year–old Dresser Formation, Pilbara Craton. Precambrian Research 337, 105534. of the ~3.48 billion–year–old Dresser Formation (Pilbara Craton, Western Australia) provide some of the oldest convincing evidence of life on Earth. Here, we augment previous evidence with a detailed investigation of the concentrations and distributions of various transition metals (Cr, Mn, Co, Ni, Cu, Zn, Mo, Se, Ag, Sn, Au, Hg, and Pb) and metalloids (As, Sb, and Te) in unweathered samples of strongly sulfidized stromatolites from drill cores. High–resolution elemental mapping and in situ compositional analysis of sulfides (pyrite and sphalerite) show that these sedimentary and hydrothermally sourced elements are strongly concentrated in texturally distinctive, nano-porous pyrite enriched in autochthonous organic matter, which forms the major, petrogenetically earliest component of wrinkly laminated and digitate growth fabrics within the stromatolites. Repeated cyclic alternations of various transition metals and metalloids (most importantly Ni and Zn), plus the presence of disconformities and overgrowth relationships between wrinkly stromatolite laminae, suggest that these element accumulations were primarily established by depositional processes during continuous stromatolite formation. Because transition metals and metalloids generally have strong affinities for organic matter, and can play active roles in biochemical processes, we interpret these element accumulations in the Dresser Formation stromatolites to be the result of binding to organic matter of living microbial communities and/or dead biomass, and perhaps also microbial utilization. Collectively, our results show that the precise characterization of transition metal–metalloid concentrations and distributions can unveil element enrichment patterns suggestive of biological activity, even in some of Earth’s oldest stromatolites.Behera, P., Mohapatra, M., Kim, J.Y., Rastogi, G., 2020. Benthic archaeal community structure and carbon metabolic profiling of heterotrophic microbial communities in brackish sediments. Science of The Total Environment 706, 135709. Archaea play a crucial role in the biogeochemical cycles and food webs, however, their spatiotemporal distribution and environmental drivers are not well investigated in brackish sediments. The composition and abundances of benthic archaeal communities were examined from a coastal lagoon; Chilika (India) which is experiencing an intense pressure from anthropogenic and natural factors. High-throughput sequencing of 16S rRNA genes revealed that sediment (n = 96) archaeal communities were largely composed of Crenarchaeota (18.76%), Euryarchaeota (18.34%), Thaumarchaeota (13.45%), Woesearchaeota (10.05%), and Pacearchaeota (4.21%). Archaeal taxa affiliated to methanogens, sulfate-reducers, and ammonia-oxidizers were detected suggesting that carbon, sulfur, and nitrogen cycles might be prominent in benthic sediments. Salinity, total organic carbon, available nitrogen, available phosphorus, macrophyte (Phragmites karka) and inter-taxa relationships between community members and with bacterial communities played steering roles in structuring the archaeal communities. Marine sites with mesohaline-polyhaline regime were dominated by Nitrosopumilus and Thaumarchaeota. In contrast, riverine sites with oligohaline regime demonstrated a higher abundance of Thermoprotei. Macrophyte dominated zones were enriched in Methanomicrobia and Methanobacteria in their rhizosphere sediments, whereas, bulk (un-vegetated) sediments were dominated by Nitrosopumilus. Spatial patterns in archaeal communities demonstrated ‘distance-decay’ patterns which were correlated with changes in physicochemical factors over geographical distances. Heterotrophic microbial communities showed much higher metabolic diversity and activity in their carbon utilization profiles in rhizosphere sediments than the bulk sediments. This baseline information on benthic archaea and their environmental drivers would be useful to assess the impact of anthropogenic and natural pressures on these communities and associated biogeochemical cycles.Bell, E., Sherry, A., Pilloni, G., Suárez-Suárez, A., Cramm, M.A., Cueto, G., Head, I.M., Hubert, C.R.J., 2020. Sediment cooling triggers germination and sulfate reduction by heat-resistant thermophilic spore-forming bacteria. Environmental Microbiology 22, 456-465. Laurentian Great Lakes are a vast, interconnected freshwater system spanning strong physicochemical gradients, thus constituting a powerful natural laboratory for addressing fundamental questions about microbial ecology and evolution. We present a comparative analysis of pelagic microbial communities across all five Laurentian Great Lakes, focusing on Bacterial and Archaeal picoplankton characterized via 16S rRNA amplicon sequencing. We collected samples throughout the water column from the major basins of each lake in spring and summer over 2?years. Two oligotypes, classified as LD12 (Alphaproteobacteria) and acI‐B1 (Actinobacteria), were among the most abundant in every sample. At the same time, microbial communities showed distinct patterns with depth during summer stratification. Deep hypolimnion samples were frequently dominated by a Chloroflexi oligotype that reached up to 19% relative abundance. Stratified surface communities differed between the colder, less productive upper lakes (Superior, Michigan, Huron) and warmer, more productive lower lakes (Erie, Ontario), in part due to an Actinobacteria oligotype (acI‐C2) that averaged 7.7% of sequences in the lower lakes but <0.2% in the upper lakes. Together, our findings suggest that both hydrologic connectivity and local selective pressures shape microbial communities in the Great Lakes and establish a framework for future investigations.Bellucci, J.J., Whitehouse, M.J., Nemchin, A.A., Snape, J.F., Kenny, G.G., Merle, R.E., Bland, P.A., Benedix, G.K., 2020. Tracing martian surface interactions with the triple O isotope compositions of meteoritic phosphates. Earth and Planetary Science Letters 531, 115977. triple oxygen isotope compositions of phosphate grains in six martian meteorites have been measured by Secondary Ion Mass Spectrometry (SIMS) and combined together with their chlorine isotope and halogen concentrations have been used to constrain hydrosphere-lithosphere interactions on Mars. These samples include three enriched shergottites (Zagami, Roberts Massif 04262 and Larkman Nunatak 12011), one depleted shergottite (Tissint), an orthopyroxenite (Allan Hills 84001), and a regolith breccia (Northwest Africa 7533). The phosphates measured here have a range in δ18O [(18O/16O)sample/(18O/16O)Standard-1] × 103] from +1.0 to +6.8‰ and could be a result of indigenous mantle values, mixing with martian water, or replacement reactions taking place on the surface of Mars. Three samples have a Δ17O [δ17O-1000(1 + δ18O /1000)0.528-1] in equilibrium with the martian mantle (ALH 84001, Tissint, and Zagami), while three samples (LAR 12011, RBT 04262, and NWA 7533) have an elevated positive Δ17O outside of analytical uncertainty of the martian fractionation line (MFL). The phosphates in the latter group also have positive and negative δ37Cl [(37Cl/35Cl)sample/(37Cl/35Cl)standard – 1] × 103] and enrichments in halogens not seen in the rest of the sample suite. Perchlorate formation on Earth fractionates Cl in both positive and negative directions and generates a correlated positive Δ17O. Further, perchlorate has been detected in wt% amounts on the martian surface. Thus, these results strongly suggest the presence of multiple Cl isotope reservoirs on the martian surface that have interacted with the samples studied here over the last ca. 2 Ga of geologic time. The weighted average of Δ17O measurements from phosphate grains (n = 13) in NWA 7533, which are the explicit result of exchange reactions on the martian surface, yields a statistically robust mean value of 1.39 ± 0.19‰ (2σ, MSWD = 1.5, p = 0.13). This value likely represents an accurate estimate for an oxidized surface reservoir on Mars.Bempong, F.K., Ozumba, B.M., Hotor, V., Takyi, B., Nwanjide, C.S., 2019. A review of the geology and the petroleum potential of the Cretaceous Tano Basin of Ghana. Journal of Petroleum & Environmental Biotechnology 10, DOI: 10.35248/2157-7463.19.10.395. is a review of the geology and the petroleum potential of the Cretaceous Tano Basin of Ghana, one of the coastal sedimentary basins in Ghana. It is located on the West African Transform Margin. It initially evolved as a pull-apart basin and later became modified by wrench faulting in the Cretaceous period. It has been known to have potentials for hydrocarbons, as indicated by oils seeps observed in the late 19th century. The presence of active source rocks deposited in the Albian to Cenomanian as well as the Turonian charges the Upper Cretaceous reservoirs sealed by widespread marine shales, as well as faulted traps and pinch-outs, has spurred exploration efforts. Thus, as expected, commercial discoveries of oil and gas have been made in the Tano Basin which evidently has become a ‘hot cake’ in deepwater exploration, even though the ultradeep water could show even more exciting hydrocarbon plays.Benucci, G.M.N., Burnard, D., Shepherd, L.D., Bonito, G., Munkacsi, A.B., 2020. Evidence for co-evolutionary history of early diverging Lycopodiaceae plants with fungi. Frontiers in Microbiology 10, 2944. doi: 10.3389/fmicb.2019. 02944. are tracheophytes in the Kingdom Plantae and represent one of the oldest lineages of living vascular plants. Symbiotic interactions between these plants with fungi and bacteria, including fine root endophytes in Endogonales, have been hypothesized to have helped early diverging plant lineages colonize land. However, attempts to study the lycopod rhizobiome in its natural environment are still limited. In this study, we used Illumina amplicon sequencing to characterize fungal and bacterial diversity in nine Lycopodiaceae (club moss) species collected in New Zealand. This was done with generic fungal ITS rDNA primers, as well as Endogonales- and arbuscular mycorrhizal fungi (AMF)-selective primer sets targeting the 18S rDNA, and generic bacterial primers targeting the V4 region of the 16S rDNA. We found that the Lycopodiaceae rhizobiome was comprised of an unexpected high frequency of Basidiomycota and Ascomycota coincident with a low abundance of Endogonales and Glomerales. The distribution and abundance of Endogonales varied with host lycopod, and included a novel taxon as well as a single operational taxonomic unit (OTU) that was detected across all plant species. The Lycopodiaceae species with the greatest number and also most unique OTUs was Phlegmariurus varius, while the plant species that shared the most fungal OTUs were Lycopodiella fastigiatum and Lycopodium scariosum. The bacterial OTU distribution was generally not consistent with fungal OTU distribution. For example, community dissimilarity analysis revealed strong concordance between the evolutionary histories of host plants with the fungal community but not with the bacterial community, indicating that Lycopodiaceae have evolved specific relationships with their fungal symbionts. Notably, nearly 16% of the ITS rDNA fungal diversity detected in the Lycopodiaceae rhizobiome remained poorly classified, indicating there is much plant-associated fungal diversity left to describe in New Zealand.Bera, G., Doyle, S., Passow, U., Kamalanathan, M., Wade, T.L., Sylvan, J.B., Sericano, J.L., Gold, G., Quigg, A., Knap, A.H., 2020. Biological response to dissolved versus dispersed oil. Marine Pollution Bulletin 150, 110713. water-soluble compounds of oil (e.g. low molecular weight PAHs) dissolve as a function of their physicochemical properties and environmental conditions, while the non-soluble compounds exist as dispersed droplets. Both the chemical and physical form of oil will affect the biological response. We present data from a mesocosm study comparing the microbial response to the water-soluble fraction (WSF), versus a water-accommodated fraction of oil (WAF), which contains both dispersed and dissolved oil components. WAF and WSF contained similar concentrations of low molecular weight PAHs, but concentrations of 4- and 5-ring PAHs were higher in WAF compared to WSF. Microbial communities were significantly different between WSF and WAF treatments, primary productivity was reduced more in WSF than in WAF, and concentrations of transparent exopolymeric particles were highest in WSF and lowest in the controls. These differences highlight the importance of dosing strategy for mesocosm and toxicity tests.Bernardin, M., Masle, A.L., Bessueille-Barbier, F., Lienemann, C.-P., Heinisch, S., 2020. Comprehensive two-dimensional liquid chromatography with inductively coupled plasma mass spectrometry detection for the characterization of sulfur, vanadium and nickel compounds in petroleum products. Journal of Chromatography A 1611, 460605. petroleum industry is increasingly concerned with the conversion of vacuum residues as a consequence of decreased conventional crude oil availability. The compositional analysis of heavy oil products has become a key step in conversion processes, but the complexity of these oil matrices tends to increase with their boiling point. In this study, comprehensive two-dimensional liquid chromatography (LCxLC) coupled to inductively coupled mass spectrometry (ICP-MS/MS) is considered with a view to meet new requirements and to bring additional information regarding the species present in these matrices. In search for a high degree of orthogonality, two separation techniques involving two different retention mechanisms were evaluated: Size Exclusion Chromatography (SEC) and Reverse Phase Liquid Chromatography (RPLC). In SEC, the analytes are separated according to their molecular weight while according to their hydrophobicity in RPLC. The separation power of both individual separation techniques was first evaluated. Off-line and on-line LCxLC were compared on the basis of an optimization approach. It is shown that off-line SECxRPLC can provide, for the same analysis time of 150 min, a higher peak capacity (2600 vs 1700) than on-line RPLCxSEC while a similar dilution factor (close to 30) but also requires far fewer fractions to be analyzed (12 vs 400). Asphaltenes which constitute the heaviest fraction of crude oils (obtained from petroleum industry) were analyzed by the developed off-line SECxRPLC method. The resulting 2D-contour plots show that co-elutions could be removed leading, for the first time, to new information on high molecular weight species containing sulfur and vanadium.Besseling, M.A., Hopmans, E.C., Bale, N.J., Schouten, S., Sinninghe Damsté, J.S., Villanueva, L., 2020. The absence of intact polar lipid-derived GDGTs in marine waters dominated by Marine Group II: Implications for lipid biosynthesis in Archaea. Scientific Reports 10, 294. marine pelagic archaeal community is dominated by three major groups, the marine group I (MGI) Thaumarchaeota, and the marine groups II and III (MGII and MGIII) Euryarchaeota. Studies of both MGI cultures and the environment have shown that the MGI core membrane lipids are predominantly composed of glycerol dibiphytanyl glycerol tetraether (GDGT) lipids and the diether lipid archaeol. However, there are no cultured representatives of MGII and III archaea and, therefore, both their membrane lipid composition and potential contribution to the marine archaeal lipid pool remain unknown. Here, we show that GDGTs present in suspended particulate matter of the (sub)surface waters of the North Atlantic Ocean and the coastal North Sea are derived from MGI archaea, and that MGII archaea do not significantly contribute to the pool of GDGTs and archaeol. This implies, in contrast to previous suggestions, that their lipids do not affect the widely used sea surface temperature proxy TEX86. These findings also indicate that MGII archaea are not able to produce any known archaeal lipids, implying that our understanding of the evolution of membrane lipid biosynthesis in Archaea is far from complete.Bhatia, S.K., Jagtap, S.S., Bedekar, A.A., Bhatia, R.K., Patel, A.K., Pant, D., Rajesh Banu, J., Rao, C.V., Kim, Y.-G., Yang, Y.-H., 2020. Recent developments in pretreatment technologies on lignocellulosic biomass: Effect of key parameters, technological improvements, and challenges. Bioresource Technology 300, 122724. biomass is an inexpensive renewable source that can be used to produce biofuels and bioproducts. The recalcitrance nature of biomass hampers polysaccharide accessibility for enzymes and microbes. Several pretreatment methods have been developed for the conversion of lignocellulosic biomass into value-added products. However, these pretreatment methods also produce a wide range of secondary compounds, which are inhibitory to enzymes and microorganisms. The selection of an effective and efficient pretreatment method discussed in the review and its process optimization can significantly reduce the production of inhibitory compounds and may lead to enhanced production of fermentable sugars and biochemicals. Moreover, evolutionary and genetic engineering approaches are being used for the improvement of microbial tolerance towards inhibitors. Advancements in pretreatment and detoxification technologies may help to increase the productivity of lignocellulose-based biorefinery. In this review, we discuss the recent advancements in lignocellulosic biomass pretreatment technologies and strategies for the removal of inhibitors.Bian, X., Wang, K., Tan, E., Diwu, P., Zhang, F., Guo, Y., 2020. A selective ensemble preprocessing strategy for near-infrared spectral quantitative analysis of complex samples. Chemometrics and Intelligent Laboratory Systems 197, 103916. of raw near-infrared (NIR) spectra is typically required prior to multivariate calibration since the measured spectra of complex samples are often subject to overwhelming background, light scattering, varying noises and other unexpected factors. Various preprocessing methods have been developed aimed at removing or reducing the interference of these effects. However, it is usually difficult to determine the best preprocessing method for a given data. Instead of selecting the best one, a selective ensemble preprocessing strategy is proposed for NIR spectral quantitative analysis. Firstly, numerous preprocessing methods and their combinations are obtained by full factorial design in order of baseline correction, scattering correction, smoothing and scaling. Then partial least squares (PLS) model is built for each preprocessing method. The models which have better predictions than PLS are selected and their predictions are averaged as the final prediction. The performance of the proposed method was tested with corn, blood and edible blend oil samples. Results demonstrate that the selective ensemble preprocessing method can give comparative or even better results than the traditional selected best preprocessing method. Therefore, in the framework of selective ensemble preprocessing, more accurate calibration can be obtained without searching the best preprocessing method.Billi, D., Mosca, C., Fagliarone, C., Napoli, A., Verseux, C., Baqué, M., de Vera, J.-P., 2020. Exposure to low Earth orbit of an extreme-tolerant cyanobacterium as a contribution to lunar astrobiology activities. International Journal of Astrobiology 19, 53-60. investigating the survival and the biomarker detectability of a rock-inhabiting cyanobacterium, Chroococcidiopsis sp. CCMEE 029, the BIOMEX space experiment might contribute to a future exploitation of the Moon as a test-bed for key astrobiology tasks such as the testing of life-detection technologies and the study of life in space. Post-flight analyses demonstrated that the mixing of dried cells with sandstone and a lunar regolith simulant provided protection against space UV radiation. During the space exposure, dried cells not mixed with minerals were killed by 2.05 × 102 kJ m?2 of UV radiation, while cells mixed with sandstone or lunar regolith survived 1.59 × 102 and 1.79 × 102 kJ m?2, respectively. No differences in survival occurred among cells mixed and not mixed with minerals and exposed to space conditions in the dark; this finding suggests that space vacuum and 0.5 Gy of ionizing radiation did not impair the cells’ presence in space. The genomic DNA of dead cells was severely damaged but still detectable with PCR amplification of a short target, thus suggesting that short sequences should be targeted in a PCR-based approach when searching for traces of life. The enhanced stability of genomic DNA of dried cells mixed with minerals and exposed to space indicates that DNA might still be detectable after prolonged periods, possibly up to millions of years in microbes shielded by minerals. Overall, the BIOMEX results contribute to future experiments regarding the exposure of cells and their biomarkers to deep space conditions in order to further test the lithopanspermia hypothesis, the biomarker stability and the microbial endurance, with implications for planetary protection and to determine if the Moon has been contaminated during past human missions.Bittremieux, W., 2020. spectrum_utils: A Python package for mass spectrometry data processing and visualization. Analytical Chemistry 92, 659-661. the wide diversity in applications of biological mass spectrometry, custom data analyses are often needed to fully interpret the results of an experiment. Such bioinformatics scripts necessarily include similar basic functionality to read mass spectral data from standard file formats, process it, and visualize it. Rather than having to reimplement this functionality, to facilitate this task, spectrum_utils is a Python package for mass spectrometry data processing and visualization. Its high-level functionality enables developers to quickly prototype ideas for computational mass spectrometry projects in only a few lines of code. Notably, the data processing functionality is highly optimized for computational efficiency to be able to deal with the large volumes of data that are generated during mass spectrometry experiments. The visualization functionality makes it possible to easily produce publication-quality figures as well as interactive spectrum plots for inclusion on web pages. spectrum_utils is available for Python 3.6+, includes extensive online documentation and examples, and can be easily installed using conda. It is freely available as open source under the Apache 2.0 license at ?, M., Klintzsch, T., Ionescu, D., Hindiyeh, M.Y., Günthel, M., Muro-Pastor, A.M., Eckert, W., Urich, T., Keppler, F., Grossart, H.P., 2020. Aquatic and terrestrial cyanobacteria produce methane. Science Advances 6, eaax5343. is accumulating to challenge the paradigm that biogenic methanogenesis, considered a strictly anaerobic process, is exclusive to archaea. We demonstrate that cyanobacteria living in marine, freshwater, and terrestrial environments produce methane at substantial rates under light, dark, oxic, and anoxic conditions, linking methane production with light-driven primary productivity in a globally relevant and ancient group of photoautotrophs. Methane production, attributed to cyanobacteria using stable isotope labeling techniques, was enhanced during oxygenic photosynthesis. We suggest that the formation of methane by cyanobacteria contributes to methane accumulation in oxygen-saturated marine and limnic surface waters. In these environments, frequent cyanobacterial blooms are predicted to further increase because of global warming potentially having a direct positive feedback on climate change. We conclude that this newly identified source contributes to the current natural methane budget and most likely has been producing methane since cyanobacteria first evolved on Earth.Boll, M., Geiger, R., Junghare, M., Schink, B., 2020. Microbial degradation of phthalates: biochemistry and environmental implications. Environmental Microbiology Reports 12, 3-15. environmentally relevant xenobiotic esters of phthalic acid (PA), isophthalic acid (IPA) and terephthalic acid (TPA) are produced on a million ton scale annually and are predominantly used as plastic polymers or plasticizers. Degradation by microorganisms is considered as the most effective means of their elimination from the environment and proceeds via hydrolysis to the corresponding PA isomers and alcohols under oxic and anoxic conditions. Further degradation of PA, IPA and TPA differs fundamentally between anaerobic and aerobic microorganisms. The latter introduce hydroxyl functionalities by dioxygenases to facilitate subsequent decarboxylation by either aromatizing dehydrogenases or cofactor‐free decarboxylases. In contrast, anaerobic bacteria activate the PA isomers to the respective thioesters using CoA ligases or CoA transferases followed by decarboxylation to the central intermediate benzoyl‐CoA. Decarboxylases acting on the three PA CoA thioesters belong to the UbiD enzyme family that harbour a prenylated flavin mononucleotide (FMN) cofactor to achieve the mechanistically challenging decarboxylation. Capture of the extremely instable PA‐CoA intermediate is accomplished by a massive overproduction of phthaloyl‐CoA decarboxylase and a balanced production of PA‐CoA forming/decarboxylating enzymes. The strategy of anaerobic phthalate degradation probably represents a snapshot of an ongoing evolution of a xenobiotic degradation pathway via a short‐lived reaction intermediate.Bolotnik, T.A., Timchenko, Y.V., Plyushchenko, I.V., Levkina, V.V., Pirogov, A.V., Smolenkov, A.D., Popik, M.V., Shpigun, O.A., 2019. Use of chemometric methods of data analysis for the identification and typification of petroleum and petroleum products. Journal of Analytical Chemistry 74, 1336-1340. method for identifying straits of rocket kerosene (RG-1 and T-1 brands) and various types of hydrocarbon fuels (aviation fuel TC-1 and diesel fuel) in soil has been developed. The proposed version of identification is based on the preliminary separation of the main components by gas chromatography and their mass spectrometric detection followed by the processing of the data obtained by chemometric methods of analysis (principal component analysis and projection on latent structures with discriminant analysis) using the “MZmineZ,” “iMet-Q,” and “MetaboAnalyst” software. A possibility of the application of the developed approach to the typification of saturated oil fractions of different origin is illustrated.Bomba, R., Rout, S.K., Bütikofer, M., Kwiatkowski, W., Riek, R., Greenwald, J., 2019. Carbonyl sulfide as a prebiotic activation agent for stereo- and sequence-selective, amyloid-templated peptide elongation. Origins of Life and Evolution of Biospheres 49, 213-224. chemical replication is a commonly assumed precursor to and prerequisite for life and as such is the one of the goals of our research. We have previously reported on the role that short peptide amyloids could have played in a template-based chemical elongation. Here we take a step closer to the goal by reproducing amyloid-templated peptide elongation with carbonyl sulfide (COS) in place of the less-prebiotically relevant carbonyldiimidazole (CDI) used in the earlier study. Our investigation shows that the sequence-selectivity and stereoselectivity of the amyloid-templated reaction is similar for both activation chemistries. Notably, the amyloid protects the peptides from some of the side-reactions that take place with the COS-activation.Bonneville, S., Delpomdor, F., Préat, A., Chevalier, C., Araki, T., Kazemian, M., Steele, A., Schreiber, A., Wirth, R., Benning, L.G., 2020. Molecular identification of fungi microfossils in a Neoproterozoic shale rock. Science Advances 6, eaax7599. fossils of fungi are sparse, and the knowledge of their early evolution and the role they played in the colonization of land surface are limited. Here, we report the discovery of fungi fossils in a 810 to 715 million year old dolomitic shale from the Mbuji-Mayi Supergroup, Democratic Republic of Congo. Syngenetically preserved in a transitional, subaerially exposed paleoenvironment, these carbonaceous filaments of ~5 μm in width exhibit low-frequency septation (pseudosepta) and high-angle branching that can form dense interconnected mycelium-like structures. Using an array of microscopic (SEM, TEM, and confocal laser scanning fluorescence microscopy) and spectroscopic techniques (Raman, FTIR, and XANES), we demonstrated the presence of vestigial chitin in these fossil filaments and document the eukaryotic nature of their precursor. Based on those combined evidences, these fossil filaments and mycelium-like structures are identified as remnants of fungal networks and represent the oldest, molecularly identified remains of Fungi.Boonchai, N., Suteethorn, S., Sereeprasirt, W., Suriyonghanphong, C., Amiot, R., Cuny, G., Legrand, J., Thévenard, F., Philippe, M., 2020. Xenoxylon, a boreal fossil wood in the Mesozoic redbeds of Southeast Asia: Potential for the stratigraphy of the Khorat group and the palinspatic reconstruction of Southeast Asia. Journal of Asian Earth Sciences 189, 104153. fossil wood genus Xenoxylon is reported in-situ for the first time in Thailand. It originates from the Indosinian terrane, from the Mesozoic continental redbeds of the Phu Kradung Formation (Khorat Group). Palinspatic reconstruction, palaeobiogeography and correlation with other occurrences of the genus, in southern China as well as in Vietnam, suggest a middle to late Jurassic age for the Phu Kradung Formation level yielding the fossil wood. The dating of this formation is still controversial and thus our data is an important step towards a better understanding of its geological history and palaeoecology, as well as of the Southeast Asia Mesozoic continental redbeds significance for the evolution of the vertebrates.Borrelli, C., Gabitov, R.I., Liu, M.C., Hertwig, A.T., Panieri, G., 2020. The benthic foraminiferal δ34S records flux and timing of paleo methane emissions. Scientific Reports 10, 1304. modern environments, pore water geochemistry and modelling simulations allow the study of methane (CH4) sources and sinks at any geographic location. However, reconstructing CH4 dynamics in geological records is challenging. Here, we show that the benthic foraminiferal δ34S can be used to reconstruct the flux (i.e., diffusive vs. advective) and timing of CH4 emissions in fossil records. We measured the δ34S of Cassidulina neoteretis specimens from selected samples collected at Vestnesa Ridge, a methane cold seep site in the Arctic Ocean. Our results show lower benthic foraminiferal δ34S values (～20‰) in the sample characterized by seawater conditions, whereas higher values (～25–27‰) were measured in deeper samples as a consequence of the presence of past sulphate-methane transition zones. The correlation between δ34S and the bulk benthic foraminiferal δ13C supports this interpretation, whereas the foraminiferal δ18O-δ34S correlation indicates CH4 advection at the studied site during the Early Holocene and the Younger-Dryas – post-B?lling. This study highlights the potential of the benthic foraminiferal δ34S as a novel tool to reconstruct the flux of CH4 emissions in geological records and to indirectly date fossil seeps.Bouamoud, R., Moine, E.C., Mulongo-Masamba, R., El Hamidi, A., Halim, M., Arsalane, S., 2020. Type I kerogen-rich oil shale from the Democratic Republic of the Congo: mineralogical description and pyrolysis kinetics. Petroleum Science 17, 255–267. Democratic Republic of the Congo holds important reserves of oil shale which is still under geological status. Herein, the characterization and pyrolysis kinetics of type I kerogen-rich oil shale of the western Central Kongo (CK) were investigated. X-ray diffraction, Fourier-transform infrared spectroscopy and thermal analysis (TG/DTA) showed that CK oil shale exhibits a siliceous mineral matrix with a consistent organic matter rich in aliphatic chains. The pyrolysis behavior of kerogen revealed the presence of a single mass loss between 300 and 550 °C, estimated at 12.5% and attributed to the oil production stage. Non-isothermal kinetics was performed by determining the activation energy using the iterative isoconversional model-free methods and exhibits a constant value with E?=?211.5?±?4.7 kJ mol?1. The most probable kinetic model describing the kerogen pyrolysis mechanism was obtained using the Coats–Redfern and Arrhenius plot methods. The results showed a unique kinetic triplet confirming the nature of kerogen, predominantly type I and reinforcing the previously reported geochemical characteristics of the CK oil shale. Besides, the calculation of thermodynamic parameters (ΔH*, ΔS* and ΔG*) corresponding to the pyrolysis of type I kerogen revealed that the process is non-spontaneous, in agreement with DTA experiments.Boulila, S., Charbonnier, G., Spangenberg, J.E., Gardin, S., Galbrun, B., Briard, J., Le Callonnec, L., 2020. Unraveling short- and long-term carbon cycle variations during the Oceanic Anoxic Event 2 from the Paris Basin Chalk. Global and Planetary Change 186, 103126. Oceanic Anoxic Event 2 (OAE2, ca. 94.6 Ma) is one of the major perturbations in the global carbon cycle during the Phanerozoic. Stable carbon isotopes (δ13C) from marine and continental sedimentary environments document this carbon cycle perturbation with a pronounced (> 2‰) positive carbon isotope excursion (CIE). Although the OAE2 stratigraphic interval has been intensively studied in terms of paleoceanography and paleoclimatology, several climatic and carbon cycle aspects are not yet well-understood. In particular, cyclic short-term Milankovitch-scale δ13C variations within the OAE2 and their potential implications for the global carbon cycle have been rarely addressed. Here, we present high-resolution (5 cm, ~2 kyr) δ13C data spanning the OAE2 from the Paris Basin Chalk (Poigny Craie-701 drill-core) to show high amplitude short-term δ13C oscillations, superimposed on the major CIE. Time-series analysis indicates that short-term oscillations are astronomically paced, with eccentricity cycles being the most prominent. Orbital forcing of δ13C variations is further supported by time-series analysis of the English Chalk (Eastbourne section). We suggest that orbitally paced carbon cycle oscillations were amplified by considerable emission of greenhouse gases from volcanism that caused the overall CIE. Astronomical calibration of the whole OAE2 (the perturbation and recovery phases) from the Poigny record provides a duration equivalent to eight to eight and a half short eccentricity cycles.Cyclostratigraphic correlations among several OAE2 key records indicate the same duration of the whole CIE. However, duration of the interval from the onset of CIE till the Cenomanian-Turonian boundary (CTB) is significantly different from one basin to another. In particular, a difference of almost two short eccentricity cycles is highlighted between the Anglo-Paris and Western Interior basins. According to cyclostratigraphic approach and correlations, the entry of W. devonense was at least 200 kyr later in the Western Interior Basin (WIB, USA) than in Europe. Key calcareous nannofossil biohorizons (e.g., Quadrum gartneri) are also stratigraphically upshifted in the WIB with respect to the European sections, hence concurring with the hypothesis of a younger CTB in the WIB. We ascribe such significant temporal offset to diachroneity of the CTB, which is likely the result of different, regional biotic responses to the global OAE2 paleoenvironmental perturbation.Bowen, G.J., Fischer-Femal, B., Reichart, G.-J., Sluijs, A., Lear, C.H., 2020. Joint inversion of proxy system models to reconstruct paleoenvironmental time series from heterogeneous data. Climate of the Past 16, 65-78. and paleoenvironmental reconstructions are fundamentally uncertain because no proxy is a direct record of a single environmental variable of interest; all proxies are indirect and sensitive to multiple forcing factors. One productive approach to reducing proxy uncertainty is the integration of information from multiple proxy systems with complementary, overlapping sensitivity. Mostly, such analyses are conducted in an ad hoc fashion, either through qualitative comparison to assess the similarity of single-proxy reconstructions or through step-wise quantitative interpretations where one proxy is used to constrain a variable relevant to the interpretation of a second proxy. Here we propose the integration of multiple proxies via the joint inversion of proxy system and paleoenvironmental time series models in a Bayesian hierarchical framework. The “Joint Proxy Inversion” (JPI) method provides a statistically robust approach to producing self-consistent interpretations of multi-proxy datasets, allowing full and simultaneous assessment of all proxy and model uncertainties to obtain quantitative estimates of past environmental conditions. Other benefits of the method include the ability to use independent information on climate and environmental systems to inform the interpretation of proxy data, to fully leverage information from unevenly and differently sampled proxy records, and to obtain refined estimates of proxy model parameters that are conditioned on paleo-archive data. Application of JPI to the marine Mg∕Ca and δ18O proxy systems at two distinct timescales demonstrates many of the key properties, benefits, and sensitivities of the method, and it produces new, statistically grounded reconstructions of Neogene ocean temperature and chemistry from previously published data. We suggest that JPI is a universally applicable method that can be implemented using proxy models of wide-ranging complexity to generate more robust, quantitative understanding of past climatic and environmental change.Bowling, T.J., Johnson, B.C., Marchi, S., De Sanctis, M.C., Castillo-Rogez, J.C., Raymond, C.A., 2020. An endogenic origin of cerean organics. Earth and Planetary Science Letters 534, 116069. deposits of aliphatic organic-rich material have been found on the surface of dwarf planet Ceres, and based on mineralogical context, it has been suggested that these organics formed within Ceres (De Sanctis et al., 2017). However, no obvious source and exposure mechanism can be inferred from the geological settings of the organic-rich terrains. The alternative hypothesis is that the organics were delivered from an exogenic source via impact (Pieters et al., 2018). We numerically simulate the thermal degradation of aliphatic organics delivered to Ceres during hypervelocity impacts, as well as the thermal degradation and excavation of organics from the subsurface. Our models show that exogenic delivery of aliphatic organics is inefficient, as most of the spectral signature of the organic species would be thermally degraded and diluted by mixing with target material in the ejecta blanket of a given crater. Instead, our models suggest that the formation of Ernutet crater excavated a subsurface reservoir of aliphatic organics from a depth of 3-6 km, bringing it close to the surface, where it could be subsequently exhumed by small craters and landslides, compatible with observations.Boyd, E.S., Amenabar, M.J., Poudel, S., Templeton, A.S., 2020. Bioenergetic constraints on the origin of autotrophic metabolism. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20190151. form the base of all complex food webs and seemingly have done so since early in Earth history. Phylogenetic evidence suggests that early autotrophs were anaerobic, used CO2 as both an oxidant and carbon source, were dependent on H2 as an electron donor, and used iron-sulfur proteins (termed ferredoxins) as a primary electron carrier. However, the reduction potential of H2 is not typically low enough to efficiently reduce ferredoxin. Instead, in modern strictly anaerobic and H2-dependent autotrophs, ferredoxin reduction is accomplished using one of several recently evolved enzymatic mechanisms, including electron bifurcating and coupled ion translocating mechanisms. These observations raise the intriguing question of why anaerobic autotrophs adopted ferredoxins as central electron carriers only to have to evolve complex machinery to reduce them. Here, we report calculated reduction potentials for H2 as a function of observed environmental H2 concentration, pH and temperature. Results suggest that a combination of alkaline pH and high H2 concentration yield H2 reduction potentials low enough to efficiently reduce ferredoxins. Hyperalkaline, H2 rich environments have existed in discrete locations throughout Earth history where ultramafic minerals are undergoing hydration through the process of serpentinization. These results suggest that serpentinizing systems, which would have been common on early Earth, naturally produced conditions conducive to the emergence of H2-dependent autotrophic life. The primitive process of hydrogenotrophic methanogenesis is used to examine potential changes in methanogenesis and Fd reduction pathways as these organisms diversified away from serpentinizing environments.Brasseur, B., 2020. A younger “earliest human migration” to Southeast Asia. Science 367, 147-148. fossiliferous Sangiran dome in Central Java contains the oldest human remains in Southeast Asia and is thus considered to be one of the most important sites in human paleoanthropology. Researchers have discovered more than 100 hominid remains from at least three different early to middle Pleistocene hominid species (1). Although numerous dating studies have been conducted at this site, the accepted date of earliest hominin migration is controversial. On page 210 of this issue, Matsu'ura et al. (2) describe their combined use of uranium/lead (U/Pb) dating (crystallization age) and fission-track dating (volcano eruption age) on zircons from three key strata in the hominid-bearing layers of Sangiran.The Sangiran dome is a recently (Upper Pleistocene) uplifted tectonic dome in a fossil-filled ～55-km2 area with 250-m-thick Quaternary outcroppings. One of the world's first potassium/argon (K/Ar) datings of a hominid-bearing layer occurred on an Australasian tektite found at the site (3). However, 55 years and 36 absolute datings later, considerable uncertainty remains regarding the potential age of Sangiran's extensive and deep fossiliferous strata. This uncertainty makes it difficult for paleoanthropologists to connect Sangiran hominids to distant Asian sites and, therefore, to unveil the relative chronology of the earliest human migrations in Southeast Asia. This uncertainty can be explained by several factors: the stratigraphic and geographic dispersal of fossils over such a large territory, decontextualized discoveries by inhabitants, and dating discrepancies.The first discoveries of artifacts and, later, of hominid fossils in the Sangiran dome were reported by von Koenigswald in the 1930s (4). The hominid fossils found led to descriptions of two new species—Meganthropus paleojavanicus and Pithecanthropus dubius—along-side Pongo sp. and the archaic and classic groups of Pithecanthropus (Homo) erectus. This hominid taxonomic richness is still under study (1) and has spurred interdisciplinary work by Indonesian-German, -Japanese, -American, and -French teams. A lithostratigraphic framework (study of strata rocks facies) consolidated by biostratigraphic observations (assigning ages to rock strata using fossils) emerged in the second half of the 20th century. Hominid fossils have been attributed, with some incertitude, to the upper part of the Sangiran black-clay formation, the upper-lying boundary Grenzbank conglomeratic layers, and Bapang fluviovolcanic formation.For 25 years, two chronological frameworks for this sedimentary sequence have been facing off. One presents a “younger” chronology for the hominid fossil layers [from between 1.3 and 1.1 million years (Ma) to between 0.7 and 0.6 Ma] and the other an “older” chronology (from between 1.7 and 1.6 Ma to 1 Ma). The “younger” framework is based on fission-track dating (zircons, amphiboles, and tektites) (5), K/Ar dating (amphiboles and tektites), and Ar/Ar dating (amphiboles) (6), along with paleomagnetism studies on fine-textured sediments, stratigraphic positions of Australasian tektite finds, and electron spin resonance dating of quartz. The “older” framework is based on Ar/Ar dating of pumice hornblende minerals (7, 8). Unfortunately, many publications dealing with early human migrations out of Africa have brushed this dating discrepancy problem under the carpet by referring to only one (mostly the “older”) of the two conflicting chronologies.The new study by Matsu'ura et al. makes a seminal contribution to the “younger” chronological framework. The three pairs of new datings show a tuff (volcanic ash from eruption) below the hominid-bearing layers to be only 1.34 Ma of age, and the fossil-rich layers of the Grenzbank and lowermost Bapang formations to be <0.97 Ma and 0.88 Ma of age, respectively. The datings of the tuff and volcaniclastic layers in the new study are based on a combination of U/Pb and fission-track dating on multiple zircon grains. Until now, the oldest hominid-bearing layers at Sangiran have been included among the rare human-bearing sites outside Africa that have been dated earlier than 1.5 Ma.Previously, deposits from the Perning hominin site in East Java were dated to the competitor age of 1.6 Ma. However, these deposits have been rejuvenated to an uncertain age of <1.49 Ma (9). Therefore, a “younger” chronology for Sangiran hominids implies that humans migrated from Asia to Southeast Asia and Java ～300,000 years later than previous estimates. This means that H. erectus's arrival on Javanese sites took place a step later relative to the Dmanisi (Georgia) and Lantian or Nihewan basin sites (China) (see the figure).In the Sangiran dome area, the oldest fully terrestrial layers constrain the first potential apparition of H. erectus fossils. These layers were characterized by in situ pedogenetic traces and terrestrial taxon stratigraphic positions. Such traces are found in the upper part of the Sangiran black-clay formation, with the underlying tuff dated, by Matsu'ura et al., to 1.3 Ma. This date can be taken as a maximal age for local hominid discoveries; however, other sites in the wider regional sedimentary basin could bear older, fully terrestrial deposits, which should be studied.In the middle of hominid-bearing strata, the Grenzbank layers, are fossil- and artifact-rich beds, now anchored at 0.9 Ma (1.6 to 1.5 Ma in the “older” chronology). Drastic worldwide changes, such as the sea level drop of 120 m induced by the first 100,000-year global glaciation cycles, began about 0.9 to 0.86 Ma. During this period, immigration via the Asian Sunda Shelf (see the figure) of new fauna and classic H. erectus populations must have strongly affected the preestablished hominid species.Researchers have yet to discover who lived with (or replaced) whom in Sangiran. For example, the hominid-rich layers of the Grenzbank zone include fossils from at least three hominid species, who might or might not have lived in the same ecosystem, depending on diachronism of this boundary layer at the dome's scale. A challenge regarding local Sangiran hominids is to correlate sedimentary sequences of remote hominid findspots through tephrostratigraphy, which uses the geochemical characteristics of tuffs (such as volcanic glass) to realize chronostratigraphic correlations. Apart from the race to the oldest hominin site, defining the chronological relations among hominid species and artifacts is an exciting field of research.References and Notes1. C. Zanolli et al., Nat. Ecol. Evol. 3, 755 (2019).2. S. Matsu'ura et al., Science 367, 210 (2020).3. G. H. R. von Koenigswald, Report of the I.N.Q.U.A. Congress VI (1964).4. G. H. R. von Koenigswald, Ingenieur Nederlansch-Indi? 1, 185 (1934).5. N. Watanabe, D. Kadar Quaternary Geology of the Hominid Fossil Bearing Formations in Java (Geological Research and Development Centre, Bandung, Indonesia, 1985).6. H. Saleki, thesis, Muséum National d'Histoire Naturelle, Institut de Paléontologie Humaine (1997).7. C. C. Swisher 3rd et al., Science 263, 1118 (1994).8. R. Larick et al., Proc. Natl. Acad. Sci. U.S.A. 98, 4866 (2001).9. M. J. Morwood et al., Aust. Archaeol. 57, 1 (2003).Brewer, T.E., Albertsen, M., Edwards, A., Kirkegaard, R.H., Rocha, E.P.C., Fierer, N., 2020. Unlinked rRNA genes are widespread among bacteria and archaea. The ISME Journal 14, 597-608. are essential to cellular life and the genes for their RNA components are the most conserved and transcribed genes in bacteria and archaea. Ribosomal RNA genes are typically organized into a single operon, an arrangement thought to facilitate gene regulation. In reality, some bacteria and archaea do not share this canonical rRNA arrangement—their 16S and 23S rRNA genes are separated across the genome and referred to as “unlinked”. This rearrangement has previously been treated as an anomaly or a byproduct of genome degradation in intracellular bacteria. Here, we leverage complete genome and long-read metagenomic data to show that unlinked 16S and 23S rRNA genes are more common than previously thought. Unlinked rRNA genes occur in many phyla, most significantly within Deinococcus-Thermus, Chloroflexi, and Planctomycetes, and occur in differential frequencies across natural environments. We found that up to 41% of rRNA genes in soil were unlinked, in contrast to the human gut, where all sequenced rRNA genes were linked. The frequency of unlinked rRNA genes may reflect meaningful life history traits, as they tend to be associated with a mix of slow-growing free-living species and intracellular species. We speculate that unlinked rRNA genes may confer selective advantages in some environments, though the specific nature of these advantages remains undetermined and worthy of further investigation. More generally, the prevalence of unlinked rRNA genes in poorly-studied taxa serves as a reminder that paradigms derived from model organisms do not necessarily extend to the broader diversity of bacteria and archaea.Broeckhoven, K., Desmet, G., 2020. Advances and challenges in extremely high-pressure liquid chromatography in current and future analytical scale column formats. Analytical Chemistry 92, 554-560. present study speculates on the potential gain we can expect of a further leap in pressure by moving from the current 1500 bar to a futuristic 3000 bar as well as reviews the main impediments to be expected when trying to realize such systems. The study focuses on so-called “analytical scale” separations, i.e., separations that are currently carried out in 2.1 mm columns, as this is the current state-of-the-art in ultrahigh-pressure liquid chromatography (UHPLC) instrumentation.Brüske, A., Weyer, S., Zhao, M.Y., Planavsky, N.J., Wegwerth, A., Neubert, N., Dellwig, O., Lau, K.V., Lyons, T.W., 2020. Correlated molybdenum and uranium isotope signatures in modern anoxic sediments: Implications for their use as paleo-redox proxy. Geochimica et Cosmochimica Acta 270, 449-474. trace metals and their isotopes have emerged as important tools that are used to reconstruct the redox-evolution of the ocean-atmosphere system. However, reliability of such reconstructions ultimately depends on a solid understanding of the proxies in the present-day oceanic system and their archival potential in sediments. This study compares isotope fractionation of molybdenum (Mo) and uranium (U) during their removal from seawater and deposition into sediments by investigating sites at various depths of the presently two largest restricted anoxic oceanic basins: The Black Sea and the Cariaco Basin. In support of previous investigations, our data indicate that Mo scavenging and isotope fractionation are mainly controlled by water column sulfide levels. In contrast to Mo, U reduction and immobilization appears to occur mainly at the sediment-water interface and within the uppermost few cm of the sediment pile in both basins. In the Black Sea, decreasing δ238U of surface sediments with increasing water depth correlate with trends for water column δ238U, implying constant U isotope fractionation between water and sediment. However, increasing U concentrations and δ238U within the uppermost few cm of the sediment pile of both basins indicate additional U reduction with depth.Despite the different mechanisms for Mo and U removal and associated isotope fractionations, a similar inverse correlation between δ98Mo and δ238U is observed for sediments of both basins, which translates in a positive correlation of Mo and U isotope fractionation between the sediments and open seawater. The correlation of δ98Mo and δ238U indicates a similar response of isotope fractionation to the efficiency of Mo and U removal that is mainly controlled by sulfate reduction rates. High dissolved sulfide concentrations and sulfate reduction rates are responsible for very effective Mo and U removal and corresponding minor Mo and U isotope fractionation relative to seawater. Further, high dissolved sulfide concentrations also correlate positively with deep water renewal times, resulting in an isotopically fractionated water column with low δ238U (and somewhat higher δ98Mo) in restricted basins with sluggish ventilations, such as the Black Sea. Both mechanisms result in negatively correlated δ98Mo and δ238U with high δ98Mo and low δ238U in sediments under strong euxinic conditions. The particularly strong correlation observed for Cariaco Basin sediments may indicate that its water column was variably stratified in the past.The observed δ98Mo and δ238U correlation of both basins can be reproduced in a simple coupled water column and sediment reactive transport model. Different slopes in δ98Mo and δ238U trends can be linked to varying degree of basin restriction, sulfate reduction rates, and isotope compositions of the respective water columns. The offset towards lower δ98Mo (and δ238U), observed for Cariaco Basin sediments compared to those from the Black Sea, may be the result of inefficient Mo reduction with high Mo isotope fractionation or isotopically light Mo from a particulate Fe-Mn oxide shuttle. The results of this study will help to interpret sedimentary Mo and U isotope values, while showing that coupling of δ98Mo and δ238U in sedimentary archives may be useful for paleo-reconstruction work.Bryanskaya, A.V., Berezhnoy, A.A., Rozanov, A.S., Serdyukov, D.S., Malup, T.K., Peltek, S.E., 2020. Survival of halophiles of Altai lakes under extreme environmental conditions: implications for the search for Martian life. International Journal of Astrobiology 19, 1-15. is considered to be one of the most favourable places in the Solar System to search for past and present life. In the past Mars was warmer and wetter, so terrestrial halophiles can be regarded as analogues of hypothetical ancient Martian halophiles. In this study we used microorganisms from unique Altai region (Russia) to estimate the capability of terrestrial bacteria and archaea to survive at low temperatures and high concentration of salts and metals, similar to the Martian environment. The current report demonstrates that both halophilic archaea and halotolerant bacteria from saline lakes of the Altai region may be considered as analogues of ancient Martian organisms, since they are able to withstand conditions that hypothetically existed in subsurface layers of the early Mars (low temperatures, salt solutions with a high content of NaCl) with only slight decrease in viability. We also found that the studied microorganisms can use some organic substances found in meteorites. We consider that transfer of unicellular halophiles from Earth to Mars was possible, and, moreover, they could successfully survive and grow on early Mars. Adjusting our growth media to the chemical composition of the lakes, from which the studied strains were isolated, resulted in significant increase in survival and growth rates. Certain strains could survive several freeze–thaw cycles at ?70 °C typical for Martian nights.Bugg, T.D.H., Williamson, J.J., Rashid, G.M.M., 2020. Bacterial enzymes for lignin depolymerisation: new biocatalysts for generation of renewable chemicals from biomass. Current Opinion in Chemical Biology 55, 26-33. conversion of polymeric lignin from plant biomass into renewable chemicals is an important unsolved problem in the biorefinery concept. This article summarises recent developments in the discovery of bacterial enzymes for lignin degradation, our current understanding of their molecular mechanism of action, and their use to convert lignin or lignocellulose into aromatic chemicals. The review also discusses the recent developments in screening of metagenomic libraries for new biocatalysts, and the use of protein engineering to enhance lignin degradation activity.Bura-Naki?, E., Sondi, I., Mikac, N., Andersen, M.B., 2020. Investigating the molybdenum and uranium redox proxies in a modern shallow anoxic carbonate rich marine sediment setting of the Malo Jezero (Mljet Lakes, Adriatic Sea). Chemical Geology 533, 119441. molybdenum (Mo) and uranium (U) isotope compositions recorded in carbonate rich sediments are emerging as promising paleo-redox proxies. However, the effects of early diagenetic effects within the sediments on these isotope systems are not well constrained. We examined the Mo and U isotopic systematics in anoxic carbonate rich sediments in a semi enclosed karstic marine lake (Malo Jezero) of the Island of Mljet, Adriatic Sea.Measurements of water column redox behavior in the lake since the 1950s, have shown a transition from anoxic-sulfidic conditions in the deeper water column to more oxic conditions and anoxia refined to the sediment and pore-waters. A 50?cm long sediment core from the deepest part of the lake, show a transition from moderate to high authigenic Mo and U accumulation with depth, consistent with the changing lake redox environment in the past. In the deep euxinic part of the core, the authigenic Mo and U are isotopically lighter and heavier, respectively, than seawater, following similar systematics as observed in other modern euxinic basins, with high, but non-quantitative, Mo and U uptake into the sediments.Based on Bahamas bank carbonate sediments, it has been suggested that the 238U/235U ratio is ~+0.25‰ higher compared to seawater from the effects of early carbonate sediment diagenesis and this carbonate vs. seawater off-set is applicable to carbonate rich sediments across the geological past. The shallower part of lake sediment core was deposited under similar redox conditions as the Bahamas sediments, and these sediments show an average 238U/235U ratio?+0.31?±?0.01‰ (2SE) higher than seawater. Although the average 238U/235U ratios for these two carbonate rich settings are similar, caution is necessary when inferring seawater 238U/235U compositions from such sediments, as they contain U from different sources (e.g. diagenetic uptake and carbonate-bound). The Mo isotope compositions within the same Malo Jezero sediments are variable but approaches the seawater composition at low pore-water H2S concentrations. This show the potential of using the Mo isotope composition from carbonate rich sediments to infer the seawater composition, however, further work is required to establish the link between the Mo isotope composition and the chemistry of the pore water environment.Buzmakov, S.A., Khotyanovskaya, Y.V., 2020. Degradation and pollution of lands under the influence of oil resources exploitation. Applied Geochemistry 113, 104443. research considers the degradation and pollution of soils as a result of oil extraction activities. The object of the research includes the territories of the exploited oil fields located in the Sarmatic mixed forests in Perm region. A total survey of the Gozhanskoye field was carried out, which revealed that the most dangerous processes of transformation and accumulation of pollutants are concentrated in the zone of influence of the primary oil treatment units (rus. UPPN, see the map). The other seven areas of the UPPNs were also surveyed. In total, 303 soil samples were taken as part of the study. The analysis determined such characteristics of oil samples as acidity, the content of humus, hydrocarbons, benzo[a]pyrene and chlorides. Measurements of oil content in the soil were carried out by the IR-spectrometry method. Benzo[a]pyrene was extracted from soil following the standard procedure and analyzed through gas chromatography testing. The physico-chemical analysis allowed to find out the concentrations of the main pollutants, as well as to design maps of land degradation and pollution. Another important finding is that the oil fields exploitation has the most essential impact on primary degradation of floodplain and upland soils as a result of salinization and benzo[a]pyrene pollution.Byrd, A.L., Vlahos, P., Whitney, M.M., Menniti, C., Warren, J.K., 2020. Tidally resolved observations of organic carbon exchange through Eastern Long Island Sound. Estuarine, Coastal and Shelf Science 232, 106463. Island Sound (LIS), is an urban estuary on the US east coast that undergoes seasonal hypoxia in its western and central regions. Approximately 90% of the water exchange between LIS and the adjacent continental shelf, the Mid Atlantic Bight, occurs through its eastern boundary. Recent estimates of organic carbon (OC) export from LIS have shown that this value varies appreciably, both seasonally and inter-annually. In this study, the spatial, tidal, and seasonal variability were resolved by measuring dissolved and particulate organic carbon (DOC and POC) concentrations and currents at a cross-section in eastern LIS near the estuary mouth. Fluxes were extrapolated from these high-resolution observations collected in May, August, and November 2016, and August 2017. In August of 2016 (a low flow year), an OC flux of 41?×?106?kg?C month?1 resulted from a net import of DOC and an export of POC. In August of 2017 (an average flow year), there was an OC flux of 30?×?106?kg?C month ?1 due to both DOC and POC export, indicating significant seasonal and inter-annual variability. The seasonally weighted-average total OC flux for 2016 was ?41?×?106 ± 9?kg?C yr?1 (net import). Results show that spot sampling in tidal estuaries can lead to spatial and tidal bias in concentrations of DOC (6–15%) and POC (31–18%) under high and low river flow conditions, respectively. This uncertainty is recommended for spot sampling in future OC studies and flux estimates in LIS.Callaway, E., 2020. Supercomputer scours fossil record for Earth’s hidden extinctions. Nature 577, 458-459. have charted 300 million years of Earth’s history in breathtaking detail. Palaeontologists have a fuzzy view of Earth’s history. An incomplete fossil record and imprecise dating techniques make it hard to pinpoint events that happened within geological eras spanning millions of years. Now, a period that saw a boom in animal complexity and one of Earth’s greatest mass extinctions is coming into sharp focus.Using the world’s fourth most powerful supercomputer, Tianhe II, a team of scientists based mostly in China mined a database of more than 11,000 fossil species that lived from around 540 million to 250 million years ago. The result is a history of life during this period, the early Palaeozoic era, that can pinpoint the rise and fall of species during diversifications and mass extinctions to within about 26,000 years. It is published on 16 January in Science1.“It is kind of amazing,” says Peter Wagner, a palaeontologist and evolutionary biologist at the University of Nebraska–Lincoln, who was not involved in the work. Being able to look at species diversity on this scale is like going from a system where “people who lived in the same century are considered to be contemporaries, to one in which only people who lived during the same 6-month period are deemed to be contemporaries”, he writes in an essay accompanying the study2.Such a view, Wagner adds, will help scientists to identify the causes of mass extinctions — such as the event at the end of the Permian period, some 252 million years ago, that wiped out more than 95% of marine species — as well as understand less dramatic species die-offs and rebounds that have been hard to uncover because of gaps in the fossil record. Understanding these processes could reveal parallels to the planet’s current loss of biodiversity.Patchy recordMost organisms in Earth’s history didn’t leave fossils, and scientists have identified only a tiny fraction of those that did. As a result, it can be hard to tell whether changes in the fossil record mark real shifts, such as mass extinctions, or are simply caused by a lack of fossil finds.In the 1960s, palaeontologists began analysing the fossil record systematically, revealing multiple mass extinctions and periods during which life flourished. But these and later efforts could usually pinpoint biodiversity changes only to within about ten million years, because fossils were lumped into relatively long geological periods and analysed en masse.To improve on this, a team led by palaeontologist Jun-xuan Fan at Nanjing University in China created and analysed a database of fossil marine invertebrate species that were found in more than 3,000 layers of rock, mostly from China but representing geology across the planet during the early Palaeozoic. The group then used software to measure when individual species had emerged and gone extinct.The program took advantage of the fact that species were usually found in multiple rock formations — each spanning hundreds of thousands to millions of years — and used this information to place upper and lower limits on the period in which the species actually existed. The effort revealed for how long, and in what order, all 11,000 species had existed. It took the supercomputer around seven million processor hours.Extinctions elucidatedUsing this approach, the team was able to learn extra details about well-documented events, such as the end-Permian extinction and the Cambrian explosion in animal diversity around 540 million years ago. The analysis showed, for instance, that species diversity declined in the 80,000 years leading up to the end-Permian mass extinction, which itself occurred over around 60,000 years.The findings also cast doubt on the existence of a smaller-scale die-off known as the end-Guadalupian extinction, which is thought to have wiped out many marine species around 260 million years ago. That was the biggest surprise, says Mike Benton, a palaeontologist at the University of Bristol, UK, who has documented changes in vertebrate diversity during that period. The study, he adds, “represents a pretty amazing big-data endeavour”.Benton hopes to see the effort extended to later periods — particularly the past 100 million years. Palaeontologists disagree over whether an apparent increase in animal diversity in this period is the result of sampling bias. “This last 100 million years has been at the heart of a long-running debate about ‘pull of the recent’ and discriminating between real signal and bias,” Benton says.Norman MacLeod, a palaeontologist at the University of Nanjing and a co-author of the study, says the team’s work might help to reveal the underlying causes of changes in biodiversity, by charting its ups and downs on a timescale that can be matched with environmental and climatic shifts.Wagner adds that the team’s approach will be most valuable in uncovering — and explaining — smaller-scale extinctions, not dissimilar to those occurring today. Such extinctions could turn out to be “a bad 100,000 years, or a bad week” for some groups of organisms but not others, he says. “When you get this resolution, it starts opening the doors to actually testing what the smaller-turnover events might be like.”References1. Fan, J-x. et al. Science 367, 272–277 (2020).2. Wagner, P. Science 367, 249 (2020Cao, F., Eskin, D., Leonenko, Y., 2020. Modeling of ex-situ dissolution for geologic sequestration of carbon dioxide in aquifers. Journal of Petroleum Science and Engineering 187, 106835. carbon dioxide (CO2) sequestration is considered to be one of the main methods to mitigate greenhouse gas (GHG) emissions. In this technology, pure CO2 is injected into an underground geological formation and since it is less dense than residual fluids, there is always a risk of leakage to the surface. To increase security of underground CO2 disposal, ex-situ dissolution can be implemented. When CO2 is dissolved in brine before injection, it significantly reduces the risks of leakage. In this approach, pure CO2 is dissolved on the surface before injection. Surface dissolution could be achieved in a pipeline operating under the pressure of a target aquifer into which the CO2 is injected. In a pipeline, CO2 droplets are dissolved being dispersed in a brine turbulent flow. In this paper, a comprehensive model of droplet dissolution along a pipeline is presented. The model accounts for droplet breakup and coalescence processes and is validated against available experimental data.Cao, H., He, W., 2020. Correlation of carbon isotope stratigraphy and paleoenvironmental conditions in the Cretaceous Jehol Group, northeastern China. International Geology Review 62, 113-128. Jehol Biota represents an important phase in the history of biological evolution on Earth. Two sites with Aptian Jehol Biota, located in western Liaoning Province and in northern Hebei Province, northeastern China, have generated a major debate about the relationships between their fossil-bearing layers, resulting in confusions about their stratigraphic correlation and biogenetic sequence. We have applied carbon isotope analysis of total organic carbon to provide new data relevant to this debate and have re-examined the connection between volcanism and carbon cycle perturbations, with consideration of the paleoenvironmental conditions. The rare earth element data show that the provenances of the Jehol Group in western Liaoning and northern Hebei were similar and derived mainly from the underlying andesite. Constrained by the radiometric age, the δ13Corg curve suggests that the Dadianzi Formation in northern Hebei is comparable to the three lacustrine layers of the Yixian Formation (ranging from the Jianshangou Bed to the Jingangshan Bed) in western Liaoning. These layers are highly correlated with the early Aptian marine sequence in Oceanic Anoxic Event 1a (OAE 1a), implying that a possible teleconnection (possibly related to a large igneous province) existed between oceanic and terrestrial realms. We also propose that the Xiguayuan Formation above the Dadianzi Formation in northern Hebei is equivalent to the Huanghuashan Breccia Bed at the top of the Yixian Formation in western Liaoning. Moreover, the δ13Corg and element geochemical data suggest that the carbon cycle perturbation and the paleolimnological environments were distinctly influenced by the effects of volcanic CO2 during the early Aptian.Cao, H., He, W., Chen, F., Kong, D., 2020. Superheavy pyrite in the Upper Cretaceous mudstone of the Songliao Basin, NE China and its implication for paleolimnological environments. Journal of Asian Earth Sciences 189, 104156. widely developed dark mudstone in the Upper Cretaceous Nenjiang Formation of the Songliao Basin is a natural archive for reconstructing the palaeoenvironment. A time series sulfur isotope study on the Nenjiang Formation reveals that authigenic pyrite from the paleo-lake is enriched in 34S relative to coeval marine sulfate in the lower Nenjiang Member I and basal Nenjiang Member II. The occurrence of 34S-enriched pyrite must be explained to understand the paleolimnological environment and the sulfur cycling during this period, for which several explanations can be advanced. Based on a comparison of various mechanisms for superheavy pyrite formation, we consider the presence of an anaerobic sulfate minimum zone (SMZ) in the paleo-lake as the most likely scenario. In this zone, sulfate was enriched in 34S through microbial sulfate reduction (MSR), and this heavy sulfate became the source for pore water or bottom water, from which superheavy pyrite was produced. The conceptual model for formation of the superheavy pyrite in the Nenjiang Formation indicates that the distribution range of the SMZ was variable in the different sedimentary stages of the Nenjiang Formation. These variations were likely related to successive inputs of sulfate from continental weathering, which led to partial mixing of sulfate and attenuation of the SMZ in the basal Nenjiang Member II.Cao, H., Wang, C., Liu, H., Jia, W., Sun, H., 2020. Enzyme activities during benzo[a]pyrene degradation by the fungus Lasiodiplodia theobromae isolated from a polluted soil. Scientific Reports 10, 865. enzyme activities of the fungus Lasiodiplodia theobromae (L. theobromae) were studied during degradation of benzo[a]pyrene (BaP). The L. theobromae was isolated from a polycyclic aromatic hydrocarbons (PAHs) contaminated soil collected from the Beijing Coking Plant in China and can potentially use BaP as its sole carbon source with a degradation ratio of up to 53% over 10 days. The activities of lignin peroxidase (LiP) and laccase (LAC) could be detected during BaP biodegradation; while manganese peroxidase (MnP) was not detected. Both glucose and salicylic acid enhanced BaP biodegradation slightly. In contrast, the coexistence of phenanthrene (PHE) inhibited BaP degradation. These metabolic substrates all enhanced the secretion of LiP and LAC. The addition of Tween 80 (TW-80) enhanced BaP biodegradation as well as the LiP and LAC activities. At the same time, TW-80 was degraded by the L. theobromae. In addition, the L. theobromae was compared to Phanerochaete chrysosporium (P. chrysosporium), which is a widely studied fungus for degrading PAH. P. chrysosporium was unable to use BaP as its sole carbon source. The activities of LiP and LAC produced by the P. chrysosporium were less than those of the L. theobromae. Additionally, the four intermediates formed in the BaP biodegradation process were monitored using GC-MS analysis. Four metabolite concentrations first increased and then decreased or obtained the platform with prolonged BaP biodegradation time. Therefore, this study shows that the L. theobromae may be explored as a new strain for removing PAHs from the environment.Caputo, M., Lyles, J.T., Salazar, M., Quave, C.L., 2020. LEGO MINDSTORMS fraction collector: A low-cost tool for a preparative high performance liquid chromatography system. Analytical Chemistry 92, 1687-1690. High Performance Liquid Chromatographic (prep-HPLC) systems are used in many research schemes including purifying products from reaction mixtures, fractionating natural product extracts, and isolating compounds. Manual fraction collection from a prep-HPLC is a common method; however, it often lacks the reproducibility of automated fraction collectors due to human error. Automated fraction collectors for prep-HPLC systems range can add thousands of dollars to the cost of prep-HPLC and are thus not always available to budgetary constrained research programs. Nevertheless, an automated fraction collector is a tremendous resource for any lab that employs prep-HPLC methods. Using LEGO MINDSTORMS pieces and easily obtained lumber and steel C-channel we were able to deploy an automated fraction collector for only a fraction of the cost of a commercial instrument. The programming software allows for a simple interface to create fraction collection programs tailored to individual HPLC methods. This fraction collector can be connected to any LC system and tailored to collect fractions in nearly any size or shaped container. This fraction collector was designed to provide maximum versatility and will make automated fraction collection more accessible to all researchers. The simple interface allows for quickly adapting the fraction collector method to any liquid chromatographic separation, no matter how complex.Cardona, P.-J., Català, M., Prats, C., 2020. Origin of tuberculosis in the Paleolithic predicts unprecedented population growth and female resistance. Scientific Reports 10, 42. data estimate the origin of Mycobacterium tuberculosis complex (MtbC) infection around 73,000 years before the common era (BCE), and its evolution to “modern” lineages around 46,000 BCE. Being MtbC a major killer of humanity, the question is how both species could persist. To answer this question, we have developed two new epidemiological models (SEIR type), adapted to sex dimorphism and comparing coinfection and superinfection for different MtbC lineages. We have attributed a higher resistance/tolerance to females to explain the lower incidence noted in this sex, a better health status in the Paleolithic compared to the Neolithic, and a higher dissemination of “modern” lineages compared to “ancient” ones. Our findings show the extraordinary impact caused by “modern” lineages, provoking the extinction of the groups infected. This could only be overcomed by an unprecedented population increase (x20 times in 100 years) and helped with the protection generated by previous infection with “ancient” lineages. Our findings also suggest a key role of female resistance against MtbC. This data obliges us to rethink the growth population parameters in the Paleolithic, which is crucial to understanding the survival of both MtbC and humans, and to decipher the nature of human female resistance against TB.Cardoso Jr., M., Chemale Jr., F., de Oliveira, C.H.E., de Souza Cruz, C.E., de Abreu, C.J., Genezini, F.A., 2020. Thermal history of potential gas reservoir rocks in the eastern Parnaíba Basin, Brazil. American Association of Petroleum Geologists Bulletin 104, 305-328. Parnaíba Basin is a major intracratonic sedimentary basin in Brazil with unconventional petroleum systems as a potential natural resource formed by the influence of igneous intrusions. To constrain the thermal history of unexplored potential reservoir rocks in the eastern part of the Parnaíba Basin, sedimentary rocks near intrusions were analyzed by petrography and thermochronology (apatite fission-track [AFT] and zircon fission-track [ZFT] dating). Petrography shows grain dissolution and carbonate pore filling generated by thermal destabilization of feldspars. The AFT results indicate partial annealing by the last magmatic event in the basin, and ZFT results show ages of maximum paleotemperature compatible with the Sardinha magmatic event (120–130 Ma). In thermal history models, rocks close to intrusions experienced maximum paleotemperatures above 300°C, which is higher than what is considered favorable for reservoir rocks. Hydrothermal fluids modified the diagenetic evolution of the succession by dissolving and precipitating carbonate cement in pore spaces. In the studied area, at distances greater than 50 m (>164 ft) from the intrusion, the rocks were not substantially altered, and in terms of paleotemperature, they can be considered potentially viable reservoirs. The thermal history analysis of potential tight gas sandstone reservoirs affected by intrusive bodies is valuable for characterizing the thermal enhancement or destruction of the reservoir’s qualities.Cerqueda-García, D., García-Maldonado, J.Q., Aguirre-Macedo, L., García-Cruz, U., 2020. A succession of marine bacterial communities in batch reactor experiments during the degradation of five different petroleum types. Marine Pollution Bulletin 150, 110775. microbial communities might be subjected to accidental petroleum spills; however, some bacteria can degrade it, making these specific bacteria valuable for bioremediation from petroleum contamination. Thus, characterizing the microbial communities exposed to varying types of petroleum is essential. We evaluated five enriched microbial communities from the northwest Gulf of Mexico (four from the water column and one from sediments). Enrichments were performed using five types of petroleum (extra light, light, medium, heavy and extra heavy), to reveal the microbial succession using a 16S rDNA amplicon approach. Four communities were capable of degrading from extra light to heavy petroleum. However, only the community from sediment was able to degrade the extra heavy petroleum. Successional changes in the microbial communities' structures were specific for each type of petroleum where genus Dietzia, Gordonia, Microvirga, Rhizobium, Paracoccus, Thalassobaculum, Sphingomonas, Moheibacter, Acinetobacter, Pseudohongiella, Porticoccus, Pseudoalteromonas, Pseudomonas, Shewanella, and Planctomyces presented differential abundance between the treatments.Cerrato, A., Cannazza, G., Capriotti, A.L., Citti, C., La Barbera, G., Laganà, A., Montone, C.M., Piovesana, S., Cavaliere, C., 2020. A new software-assisted analytical workflow based on high-resolution mass spectrometry for the systematic study of phenolic compounds in complex matrices. Talanta 209, 120573. are a broad class of plant secondary metabolites which carry out several biological functions for plant growth and protection and are of great interest as nutraceuticals for their antioxidant properties. However, due to their structural variability and complexity, the mass-spectrometric analysis of polyphenol content in plant matrices is still an issue. In this work, a novel approach for the identification of several classes of polyphenol derivatives based on ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry was developed. First, mass-spectrometric parameters were optimized in order to obtain a large set of diagnostic product ions for their high-confidence identification. The software Compound Discoverer 3.0 was then implemented with a comprehensive database of 45,567 polyphenol derivatives and with mass-spectrometric data for their building blocks, resulting in a specific tool for the semi-automatic identification of flavonoids, anthocyanins, ellagitannins, proanthocyanidins and phenolic acids. The method was then applied to the identification of polyphenols in industrial hemp (Cannabis sativa), a matrix whose use is recently spreading for pharmaceutical and nutraceutical purposes, resulting in the identification of 147 compounds belonging to the classes of flavonoids, proanthocyanidins and phenolic acids. The proposed method is applicable to the polyphenol profiling of any plant matrix and it is not dependent on data in the literature for their identification, allowing the discovery of compounds which have been never identified before.Chan, E.W., Shiller, A.M., Joung, D.J., Arrington, E.C., Valentine, D.L., Redmond, M.C., Breier, J.A., Socolofsky, S.A., Kessler, J.D., 2020. Investigations of aerobic methane oxidation in two marine seep environments: Part 2 - Isotopic kinetics. Journal of Geophysical Research: Oceans 124, 8392-8399.: During aerobic oxidation of methane (CH4) in seawater, a process which mitigates atmospheric emissions, the 12C‐isotopologue reacts with a slightly greater rate constant than the 13C‐isotopologue, leaving the residual CH4 isotopically fractionated. Prior studies have attempted to exploit this systematic isotopic fractionation from methane oxidation to quantify the extent that a CH4 pool has been oxidized in seawater. However, cultivation‐based studies have suggested that isotopic fractionation fundamentally changes as a microbial population blooms in response to an influx of reactive substrates. Using a systematic mesocosm incubation study with recently collected seawater, here we investigate the fundamental isotopic kinetics of aerobic CH4 oxidation during a microbial bloom. As detailed in a companion paper, seawater samples were collected from seep fields in Hudson Canyon, U.S. Atlantic Margin, and atop Woolsey Mound (also known as Sleeping Dragon) which is part of lease block MC118 in the northern Gulf of Mexico, and used in these investigations. The results from both Hudson Canyon and MC118 show that in these natural environments isotopic fraction for CH4 oxidation follows a first‐order kinetic process. The results also show that the isotopic fractionation factor remains constant during this methanotrophic bloom once rapid CH4 oxidation begins and that the magnitude of the fractionation factor appears correlated with the first‐order reaction rate constant. These findings greatly simplify the use of natural stable isotope changes in CH4 to assess the extent that CH4 is oxidized in seawater following seafloor release.Plain Language Summary: The aerobic oxidation of methane in seawater is a process that prevents methane produced in the oceanic environment from being emitted to the atmosphere. During this process, isotopic forms of methane are oxidized at slightly different rates leading to changes in the natural methane isotope ratios with the extent of oxidation. While these changes in isotope ratios would seem to be a proxy for the extent of methane oxidation, laboratory‐based studies involving pure cultures have shown that these isotope ratio changes vary as a microbial population blooms in response to an increase in substrates. This study systematically measured the stable isotope changes that are associated with aerobic methane oxidation in recently collected seawater collected from regions of active seafloor methane release along the U.S. Atlantic margin and the Gulf of Mexico. Results show that these isotope changes are systematic during methane oxidation, greatly simplifying the use of isotope changes to determine the extent of methane oxidation.Chen, C., Sun, J., Zhang, Y., Mu, J., Li, W., Song, Y., 2020. Adsorption characteristics of CH4 and CO2 in organic-inorganic slit pores. Fuel 265, 116969. is very meaningful to study the adsorption characteristics of CH4 and CO2 in shale pores in the context of CO2 sequestration and enhanced gas recovery. However, as far as the authors’ knowledge, the study of gas adsorption in organic – inorganic pores is blank. The graphene – montmorillonite (MMT) pore is proposed as a model for shale matrix, and the effect of heterogeneous surface on the adsorption behavior of CH4 and CO2 in slit pores was studied by molecular dynamics (MD) method. More reasonable criteria have been adopted for the definition of free zones and adsorption zones. The adsorption characteristics and adsorption isotherms of CH4 and CO2 were analyzed, and the microscopic mechanism of gas adsorption was revealed from the molecular perspective. It was found that the heterogeneous surface caused the density distribution of the gas within the slit pores to be asymmetrical. The graphene surface shows a significantly stronger adsorption capacity than MMT, and this adsorption advantage decreases with increasing pressure. Compared with CH4, the effect of heterogeneous surface on CO2 adsorption behavior is more significant. As the pressure increases, the adsorption layer of CO2 shows a tendency to gradually become saturated. This work provides a theoretical basis for optimizing the exploitation of shale gas and geological storage of carbon dioxide.Chen, F., Wang, X., Li, N., Cao, J., Bayon, G., Peckmann, J., Hu, Y., Gong, S., Cheng, H., Edwards, R.L., Ning, Y., Jin, M., Huang, H., Wu, C., Sun, Y., Chen, H., Zhou, Y., Chen, D., Feng, D., 2019. Gas hydrate dissociation during sea-level highstand inferred from U/Th dating of seep carbonate from the south China Sea. Geophysical Research Letters 46, 13928-13938.: Gas hydrates represent a huge reservoir of methane in marine sediments, prone to dissociation in response to environmental changes. There is consensus that past events of gas hydrate dissociation in the marine environment mainly occurred during periods of low sea level. Here, we report geochemical data for 2‐m‐thick layers of seep carbonate collected from a hydrate‐bearing drill core from ~800‐m water depth in the northern South China Sea. The aragonite‐rich carbonates reveal positive δ18O values, confirming a genetic link with gas hydrate dissociation. Uranium‐thorium dating of seep carbonates indicates that gas hydrates at the study site dissociated between 133,300 and 112,700 years BP, hence coinciding with the Last Interglacial (MIS 5e) sea‐level highstand. We put forward the concept that a climate‐driven increase in temperature was responsible for a period of pronounced gas hydrate dissociation.Plain Language Summary: The gas hydrate reservoir is a dynamically changing system extremely susceptible to variations of seafloor temperature and pressure. Therefore, gas hydrate dissociation and subsequent methane seepage frequently occur during times of global climate change, especially during sea‐level lowstands with reduced seabed pressure. However, this conclusion was mainly based on dating of seep carbonates sampled from the seabed. As a consequence, one cannot exclude that previous results have been compromised by a sampling bias since seafloor samples are easier to collect. Authigenic seep carbonates from drill cores represent a continuous record of gas hydrate dynamics. Our uranium‐thorium dating of seep carbonate from drill cores provides a unique example of the effects of temperature and pressure on the stability of the hydrate system in the Dongsha area, northern South China Sea (SCS), during the last interglacial stage (MIS 5e, about 130,000 years BP). Representing the most similar and most contemporary analog to the current interglacial, the study of a methane release event in the SCS during MIS 5e will shed light on the expected trend of methane release events in the future, while providing insight into the response of low‐latitude oceans to climate change.Chen, G., Chen, D., Li, F., Liu, T., Zhao, Z., Cao, F., 2020. Dual nitrogen-oxygen isotopic analysis and kinetic model for enzymatic nitrate reduction coupled with Fe(II) oxidation by Pseudogulbenkiania sp. strain 2002. Chemical Geology 534, 119456. microbially mediated coupling process of nitrate reduction and Fe(II) oxidation (NRFO) plays important role in widespread nitrogen and iron biogeochemical cycles in the natural environments, the underlying mechanism of NRFO is still not clearly understood. Here, N and O isotope fractionation during microbial nitrate reduction by Pseudogulbenkiania sp. strain 2002 with or without Fe(II) were investigated. The nitrate reduction rate decreased substantially in the presence of Fe(II), and cells became encrusted with Fe(III) minerals. However, the N isotope enrichment factors (ε) with or without Fe(II) were identical within uncertainty (24.1 ± 2.4‰ and 25.1 ± 2.4‰), implying that Fe(II) oxidation had little influence on the extent of N isotope fractionation and that cell encrustation was unlikely to cause additional mass transfer limitation. Isotopic composition ratios of 18O to 15N (18ε: 15ε) were 0.73 ± 0.13 with and 0.50 ± 0.08 without Fe(II), close to reported values for nitrate reduction by periplasmic nitrate reductases, implying that enzymatic nitrate reduction mainly occurs in strain 2002's periplasmic space. A kinetic model based on elementary reactions was established, and rate constants of enzymatic nitrate reducing reactions were obtained in a living cell system. Combining dual N-O isotope fractionation analysis with kinetic modeling is a promising approach for interpreting diverse enzymatic pathways during NRFO processes.Chen, J., Jia, W., Xiao, Z., Peng, P.a., 2020. Catalytic hydropyrolysis of asphaltenes in marine oil from the Tarim Basin, NW China: Implications to complicated oil charging histories in an old composite basin. Marine and Petroleum Geology 114, 104232. asphaltenes have been used to characterize the source(s) and timing of expulsion of early charged oils. However, the application on asphaltene in a complex petroleum basin have been limited. Marine oils from the Tarim Basin, NW China, were selected to release asphaltene-bound molecules by the catalytic hydropyrolysis technique (Hypy). The analyzed samples were 10 heavy oils from two major oil-production regions (the Tabei and Tazhong uplifts) in the basin. The asphaltenes may be mixed products from multiple hydrocarbon charging stages, if we consider the main oil filling events and the regional geothermal histories of corresponding reservoirs. However, the similar molecular and isotopic characteristics of the hydropyrolyzates indicate contributions from one major source rock (possibly lower Cambrian mudstone) during relatively early periods, based on the presently known source characteristics. The preservation of asphaltenes probably reflects a low reservoir temperature after charging. The asphaltenes were derived from marine algae deposited in a strongly reducing environment, given the biomarker data (e.g., relatively abundant aryl isoprenoids and low Pr/Ph) and carbon isotopic data (?35.5‰ to ?34.4‰). Asphaltenes were expelled around the oil generation peak. Moreover, molecular ratios indicative of maturity (e.g., tricyclic terpanes/hopanes), derived by Hypy of asphaltenes, suggest that the asphaltenes of the Tazhong Uplift are generally more mature than those of the Tabei Uplift. Moreover, this is mainly related to different maturities when the oil was expelled. The free hydrocarbons in the Tazhong Uplift show greater molecular and isotopic variations than those in the Tabei Uplift. This might be attributed to more complex accumulation processes in the former. Late oils with a range of maturities, mixing proportions with early biodegraded oils, and degrees of alteration by thermochemical sulfate reduction could all have played a role in generating this variability. The results indicate that the hydrocarbons released from oil asphaltenes by Hypy can provide insights into multiple charging processes in an old composite petroleum basin.Chen, L., Jin, M., Wang, X., Wang, H., Li, N., 2020. The effects of diagenetic processes and fluid migration on rare earth element and organic matter distribution in seep-related sediments: A case study from the South China Sea. Journal of Asian Earth Sciences 191, 104233. seepage is an important factor governing microbial activity in marine sediments, although its impact on the distribution of rare-earth elements (REEs) and organic matter in sediments is unclear. Here, we report isotope signatures of organic (δ13CTOC) and inorganic (δ13CTIC) carbon as well as total REEs contents of core sediments collected from a well-characterized seep area on the northern South China Sea. Previous studies have identified sediments corresponding to three methane-release events (MREs) in the studied core: MRE I at 4.0–5.5 m, MRE II at 7.4–8.2 m, and MRE III at 10.0–11.5 m depth intervals. Increased methane flux and reducing bottom waters during MRE I resulted in a higher accumulation of marine-sourced organic matter, as indicated by lower C/N ratios and higher δ13CTOC values compared with those of MREs II and III. Sediments deposited during MRE I have relatively low total REE contents, which may be related to reduced REE adsorption on Mn oxyhydroxides. However, the absence of Ce anomaly at MRE I is more likely due to the detrital input that obscures the original Ce anomaly. In the MRE III sediments, a weak negative Eu anomaly relative to that in the MRE I and II may be attributed to the reduction of Eu3+ to Eu2+ under strongly reducing conditions that caused by intense methane seepage. These observations demonstrate that fluid flow may have an important effect on the distribution of both organic matter and REEs in methane-rich marine sediments.Chen, L., Lu, Y., Li, J., Guo, X., Jiang, S., Luo, C., 2020. Comparative study on the Lower Silurian Longmaxi marine shale in the Jiaoshiba shale gas field and the Pengshui area in the southeast Sichuan Basin, China. Geosciences Journal 24, 61-71. Jiaoshiba shale gas field and Pengshui area are both located in the southeast Sichuan Basin with only 100 km apart. Although these two areas obtained shale gas flow from the Lower Silurian Longmaxi marine shale, there is a huge difference of production in these two areas where the Jiaoshiba shale gas field is more productive than the Pengshui area. In order to figure out the reason that caused this difference, this study analyzed the Longmaxi marine shale in these two areas by using drilling cores, and mineralogical and geochemical data. The results show that the Jiaoshiba shale gas field has a higher quality shale reservoir (higher content of quartz, higher porosity, higher permeability and higher TOC (Total Organic Carbon)) in the Lower Silurian Longmaxi Formation than that of the Pengshui area. The Lower Silurian Longmaxi marine shale in the Jiaoshiba shale gas field contains a higher total gas content (3.65 m3/ton in average) than that of the Pengshui area (1.19 m3/ton in average). Through structure analysis, this study found that the Jiaoshiba shale gas field and the Pengshui area located in the different tectonic units. The Jiaoshiba shale gas filed is located in the East Sichuan fold belt (wide spaced anticlines area) at the west side of the Qiyue mountain fault where less fractures are developed and the pressure coefficient is more than 1.5, resulting in much more free gas preserved in the shale reservoirs in the Lower Silurian Longmaxi Formation (the ratio of free gas content and absorbed gas content is 1.6), while the Pengshui area is located in the Hunan-Hubei-Guizhou thrust belt area at the east side of the Qiyue mountain fault where much more fractures are developed and the pressure coefficient is less than 1.0, leading to less free gas preserved in the Longmaxi marine shale (the ratio of free gas content and absorbed gas content is 0.6), that is why the shale reservoir in the Pengshui area has a lower total gas content than that in the Jiaoshiba shale gas field.Chen, L., Yang, J., Wu, L., 2020. Modeling the dispersion of dissolved natural gas condensates from the Sanchi incident. Journal of Geophysical Research: Oceans 124, 8439-8454.: An Iranian tanker with 136,000 tons of natural gas condensates collided with a freighter in the East China Sea in January 2018 and, after drifting ablaze for 8 days and over 200 km, capsized on the edge of the shelf near the Kuroshio Current. Different from the crude oil, the condensates consist of hydrocarbons that have relatively high solubility in seawater. We postulate that the leakage from the remaining condensate cargo at 110 m depth may result in a bottom layer of condensate‐enriched water in the vicinity of the resting tanker. A model is constructed in this study to simulate the dispersion of contaminated water through the processes of oceanic advection, diffusion, biodegradation, and volatilization. It is found that the scope and magnitude of the dispersion are most sensitive to the biodegradation. Even though the biodegradation time scale depends on several factors that are not well quantified in this region, using any value within the estimated range from a previous study results in significant contamination in the broad area. The dispersion is particularly effective in this incident because the tanker capsized near the Kuroshio Current—a fast‐moving western boundary current. The Kuroshio acts as a fast conduit to spread the contaminant to the east coast of Japan and the interior Pacific Ocean. In addition, we identify that the Tsushima Warm Current, a perennial flow into the Japan Sea, is the second major conduit for spreading the polluted water. This study indicates that dissolved hydrocarbons are the main environmental risk for maritime spills of natural gas condensates.Plain Language Summary: The spill of the natural gas condensates in the East China Sea was unprecedented and the first major maritime spill of this kind in history. Unlike the more commonly spilled crude oil, the condensates are highly volatile and become invisible within days. However, the condensates mainly consist of low molecular weight hydrocarbons that have high solubility in seawater. Once dissolved in seawater, it is removed mainly by microbiologic processes that may take months to years. It is postulated in this study that the underwater leakage from the sunken tanker may result in a bottom layer of condensate‐enriched water. In this study we formulate a model to examine how the contaminant water spread by oceanic processes. It is found that the scope and magnitude of the dispersion are most sensitive to how long the marine microorganism can consume the dissolved contamination. In this incident, the contaminant is shown to spread over a large area because of the proximity of the source to the Kuroshio Current.Chen, N.-C., Yang, T.F., Hong, W.-L., Yu, T.-L., Lin, I.-T., Wang, P.-L., Lin, S., Su, C.-C., Shen, C.-C., Wang, Y., Lin, L.-H., 2020. Discharge of deeply rooted fluids from submarine mud volcanism in the Taiwan accretionary prism. Scientific Reports 10, 381. and quantitative assessments of fluid cycling are essential to address the role and transport of deeply sourced fluids in subduction systems. In this study, sediment cores distributed across a submarine mud volcano (SMV) offshore southwestern Taiwan were investigated to determine the characteristics of fluids generated through the convergence between the Eurasian and Phillippine Sea Plates. The low dissolved chloride concentration combined with the enrichment of 18O, and depletion of 2H of pore fluids suggest the discharge of deep freshwater formed by smectite dehydration at an equilibrium temperature of 100 to 150?°C. The upward fluid velocities, decreasing from 2.0 to 5.0?cm?yr?1 at the center to a negligible value at margin sites, varied with the rate and efficiency of anaerobic methanotrophy, demonstrating the impact of fluid migration on biogeochemical processes and carbon cycling. By extrapolating the velocity pattern, the flux of fluids exported from 13 SMVs into seawater amounted up to 1.3–2.5?×?107?kg?yr?1, a quantity accounting for 1.1–28.6% of the smectite-bound water originally stored in the incoming sediments. Our results imply that SMVs could act as a conduit to channel the fluids produced from great depth/temperature into seafloor environments in a subduction system of the western Pacific Ocean.Chen, P.H., Venegas Jimenez, J.L., Rowland, S.M., Quinn, J.C., Laurens, L.M.L., 2020. Nutrient recycle from algae hydrothermal liquefaction aqueous phase through a novel selective remediation approach. Algal Research 46, 101776. have received increasing interest in the past several decades as a biofuel feedstock source. However, sustainable nutrient supply has presented algal biofuels with a major obstacle in the value chain. At a scale where algal biofuels would meet a significant portion of transportation fuel needs, the demand for nutrients, specifically nitrogen and phosphorus, would exceed current global agricultural production. One downstream conversion pathway, hydrothermal liquefaction (HTL), produces bio-crude oils from wet algal biomass with a waste aqueous phase (HTL-AP), containing a significant amount of carbon and nitrogen. While this stream is rich in organic content and nutrients, it also contains toxic components, which include heterocyclic nitrogen compounds and phenolic compounds. Thus, the recyclability and potential toxicity of HTL-AP need to be studied in detail. The feasibility of utilizing nutrients available in HTL-AP was experimentally determined for Chlorella vulgaris and Desmodesmus armatus monocultures. Our work focused on determining the tolerance of these algae species toward HTL-AP toxicity through varying dilutions. Nitrogen replacement in the growth media was varied from a low of 18% to a high of 141% across both species. The most notable of these results show that addition of a 100× dilution (35% nitrogen replacement) of untreated HTL-AP decreased growth in C. vulgaris by 47 ± 7% with respect to a control medium. Adsorption treatments, including activated carbon and various resins, were introduced to remediate the HTL-AP toxic effects. Treatment of the HTL-AP portion with an ion-exchange resin, Dowex 50WX8, supported C. vulgaris growth at a 100× dilution (35% nitrogen replacement) with no statistical change compared to the control. An in-depth molecular profiling demonstrated for the first time the selective removal of high?nitrogen containing components by resin treatment. This work provides a foundation for studying the toxic components of HTL-AP and possible mechanisms by which treatments can remove these components.Chen, S., Liu, Z., Jiang, S., Hou, H., 2020. Carbonization: A feasible route for reutilization of plastic wastes. Science of The Total Environment 710, 136250. not only bring convenience and color to human life, but also bring endless troubles and disaster to our environment. Reutilization of plastic wastes is in favor of energy conservation and emission reduction, thereby is a significant pathway of plastic wastes disposal. Carbonization is an effective way of converting polymer precursors to valuable carbon materials for use in fields of energy conversion and storage, environmental protection and restoration. Here, we present a systematic multi-perspective overview of carbonization as a feasible route of reutilization of plastic wastes. A brief summary of conventional routes for plastic wastes is followed by a brief introduction of carbonization for converting plastics to carbon materials. Special emphasis is paid on the carbonization pathways and mechanisms of common plastics. Finally, the feasibility, application prospect and challenge of carbonization as one method of reutilization of plastic wastes are proposed. By presenting a consolidated information source on different carbonization mechanisms, this review provides a valuable guideline for reutilization of plastic wastes by carbonization.Chen, S., Sun, S., Xu, Y., Chen, F., Liu, J., 2020. Halobellus captivus sp. nov., an extremely halophilic archaeon isolated from a subterranean salt mine. Antonie van Leeuwenhoek 113, 221-231. extremely halophilic archaeon, strain ZY21T, was isolated from a subterranean rock salt sample in Yunnan, China. Colonies of strain ZY21T on nutrient-rich agar plates are orange, wet and transparent. Cells are pleomorphic, motile, Gram-stain negative and lyse in distilled water. Cells can grow at 20–55 °C (optimum 42 °C), in the presence of 15–30% (w/v) NaCl (optimum 18–20%) and at pH 6.0–9.5 (optimum 7.5). Mg2+ is required for growth (optimum 0.3 M). The major polar lipids of strain ZY21T are phosphatidylglycerol, phosphatidylglycerol sulfate and phosphatidylglycerol phosphate methyl ester, sulfated mannosyl-glucosyl-glycerol diether-1 and seven unidentified glycolipids. Sequence similarity searches with the 16S rRNA gene and rpoB′ gene showed that strain ZY21T is closely related to Halobellus rufus CBA1103T (sequence similarities: 97.5% for 16S rRNA gene and 93.3% for rpoB′ gene). The DNA G+C content of strain ZY21T was determined to be 63.0 mol% based on the draft genome sequence. Genome-based sequence similarity analysis showed that the values of the ANI, AAI, and DDH were far below the boundary for delineation of new species. Phenotypic, chemotaxonomic characteristics and phylogenetic properties suggest that strain ZY21T represents a novel species in the genus Halobellus, for which the name Halobellus captivus sp. nov. is proposed. The type strain is ZY21T (=?CGMCC 1.16343T?=?NBRC 113439T).Chen, S., Wang, P., Liu, H., Xie, W., Wan, X.S., Kao, S.-J., Phelps, T.J., Zhang, C., 2020. Population dynamics of methanogens and methanotrophs along the salinity gradient in Pearl River Estuary: implications for methane metabolism. Applied Microbiology and Biotechnology 104, 1331-1346., a major greenhouse gas, plays an important role in global carbon cycling and climate change. Methanogenesis is identified as an important process for methane formation in estuarine sediments. However, the metabolism of methane in the water columns of estuaries is not well understood. The goal of this research was to examine the dynamics in abundance and community composition of methanogens and methanotrophs, and to examine whether and how they take part in methane metabolism in the water columns from the lower Pearl River (freshwater) to the coastal South China Sea (seawater). Quantitative PCR (qPCR) and high-throughput sequencing results showed that the abundance of methanogens decreased with increasing salinity, suggesting that growth of these methanogens in the Pearl River Estuary may be influenced by high salinity. Also, the methane concentration in surface waters was lower than that in near-bottom waters at most sites, suggesting sediment methanogens are a likely source of methane. In the estuarine mixing zone, significantly high methane concentrations existed with the presence of salt-tolerant methanogens (e.g., Methanomicrobiaceae, Methanocella, Methanosaeta and Methanobacterium) and methanotrophs (e.g., Methylocystis and Methylococcaceae), which were found in brackish habitats. Furthermore, a number of methanotrophic OTUs (from pmoA gene sequence data) had specific positive correlations with methanogenic OTUs (from mcrA gene sequence data), and some of these methanogenic OTUs were correlated with concentrations of particulate organic carbon (POC). The results indicate that methanotrophs and methanogens may be intimately linked in methane metabolism attached with particles in estuarine waters.Chen, X., Wu, D., Huang, X., Lv, F., Brenner, M., Jin, H., Chen, F., 2020. Vegetation response in subtropical southwest China to rapid climate change during the Younger Dryas. Earth-Science Reviews 201, 103080. of past biotic responses to rapid climate shifts are useful for developing biological scenarios that may result from future climate change. In this context, the Younger Dryas (YD) cold climatic reversal (~12,800–11,500 cal yr BP), and the resulting vegetation response, is of considerable interest. In this study, we conducted pollen and grain-size analyses of a section spanning the interval of 17,600–8500 cal yr BP in a sediment core from Xingyun Lake, in Yunnan Province, southwest China. At the same time, the other 44 paleovegetation sites from Yunnan Plateau and elsewhere in China were reviewed. Our aims were to investigate the vegetation responses to climate changes during the YD and to integrate them with climate simulation results. During the YD climatic reversal, mean annual temperatures in Yunnan were ~1.5–2.4 °C colder than today. The vegetation response to the cooling during the YD was characterized by downward shifts in the elevation of vegetation zones. Notably, only a relatively small proportion of taxa, i.e., Abies, Picea, Pinus, Quercus (E), Quercus and Poaceae, were climatically sensitive during the YD, and changes in spring temperature were a major factor on the vegetation dynamics. In addition, there was a time lag in the vegetation response to the YD event in the Yunnan Plateau. Consistent with other records from China, the YD climatic reversal only caused a change in vegetation composition rather than vegetation type succession. Notably, there was a latitudinal gradient in the magnitude of the YD cold event in China and in the resulting vegetation response. Changes in both temperature and precipitation were responsible for the vegetation changes at mid-to-high-latitudes, whereas the vegetation dynamics at low latitudes were determined largely by changes in spring temperature.Chen, X., Zhu, L., Cui, C., Zhu, Y., Zhou, Z., Qi, F., 2020. In situ atmospheric pressure photoionization mass spectrometric monitoring of initial pyrolysis products of biomass in real time. Analytical Chemistry 92, 603-606. on the initial and intermediate pyrolysis products of biomass is essential for the mechanistic investigation of biomass pyrolysis and further optimization of upgrading processes. The conventional method can only detect the final products, which do not resemble the initial or intermediate pyrolysis products. Here, we introduce a direct orifice sampling combined with atmospheric pressure photoionization mass spectrometry (APPI-MS) for in situ online analysis of the evolved volatile initial products from the pyrolysis of biomass. Pyrolysis experiments of both dimeric model compound (guaiacylglycerol-β-guaiacyl ether, GGGE) and poplar wood were carried out to validate the generality of the method. Generally, secondary reactions can be reduced by shortening the distance between the sample and sampling orifice. Large molecular-weight initial products up to trimers were detected during the pyrolysis of poplar wood, and no initial products larger than trimers were detected. It is inferred that in situ APPI immediately after sample extraction ensures efficient and effective product detection. Furthermore, the present work offers a promising feasible method for online tracing of reaction intermediates not only in pyrolysis but also in various reactive processes (e.g., catalytic reaction, oxidation) under operando conditions.Chen, Y., Deng, B., Zhang, J., 2020. Shallow gas in the Holocene mud wedge along the inner East China Sea shelf. Marine and Petroleum Geology 114, 104233. seismic surveys were carried out in the inner shelf of the East China Sea to investigate the distribution of shallow gas in Holocene sediments. Shallow gas is distributed extensively in the Holocene strata of the shelf which is dominated by the Yangtze River. Organic-rich, fine-grain sediments deposited throughout the Holocene are essential for gas generation and accumulation. The thickness of the Holocene sediment is the main controlling factor determining the distribution of shallow gas. Gas seepages were found mostly at a water depth up to 20?m, where sediment erosion mainly occurs. Coincidence between shallow gas seepage and high methane concentration in the water column suggests that gas emission from these sediments is a potentially significant source of greenhouse gas. The interaction between shallow gas migration and coastal erosion would therefore potentially lead to increased greenhouse gas emission and accelerated sediment erosion. Such results can be applied to other costal locations around the world.Cheng, B., Liu, H., Cao, Z., Wu, X., Chen, Z., 2020. Origin of deep oil accumulations in carbonate reservoirs within the north Tarim Basin: Insights from molecular and isotopic compositions. Organic Geochemistry 139, 103931. amounts of light oil have been produced from carbonate reservoirs at depths below 7?km in the recently discovered Shunbei and Yuecan oil fields within the north Tarim Basin. Eighteen samples were investigated for molecular and isotopic compositions to help understand the origin of these deep oil accumulations. Several ratios based on C6 and C7 hydrocarbons suggest that they were not affected by evaporative fractionation. Linear relationships between the carbon number and log of the mole fraction of n-alkanes support no fractionation alteration. The correlation between concentrations of methyldiamantanes and stigmastane indicates that these oils were not severely cracked and probably at the beginning or an early stage of intense oil cracking. C29 sterane isomerization ratios 20S/(20S?+?20R) and ββ/(ββ?+?αα) have reached their equilibrium points while a good linear relationship between the concentrations of terpanes and steranes suggests variations in maturity. Calculated vitrinite reflectance of source rocks based on phenanthrene and diamondoid hydrocarbons shows different ranges, which may reflect multiple oil charges to these deep oil accumulations. A narrow range of δ13C values of whole oil and oil fractions suggest a genetic correlation of these oils. Triangular plots based on C6 and C7 hydrocarbons and diamantanes also indicate a very similar source. In addition, several ratios based on n-alkanes, isoprenoids, tri-, tetra-, and pentacyclic saturated hydrocarbons support a common source. However, oil SB7 seems to differ from the others in terms of source rock depositional environment, indicated by its much higher pristane/phytane ratio and lower dibenzothiophene/phenanthrene ratio as well as a much lower dibenzothiophenes concentration.Cheng, L., Wu, Y., Huang, S., Fang, S., Ma, M., Xue, Y., Jia, P., 2020. A comprehensive model for simulating gas flow in shale formation with complex fracture networks and multiple nonlinearities. Journal of Petroleum Science and Engineering 187, 106817. gas reservoirs are characterized by gas adsorption and multiple flow mechanisms in shale matrix and complex fracture networks after hydraulic fracturing stimulation. It is of significance to capture the dynamic pressure-dependent properties, including gas PVT properties, gas desorption, flow mechanisms, and stress-dependent fracture permeability. In this paper, this problem is handled by proposing a novel Green element method, which is a good extension of the traditional boundary element method. The domain is discretized into many Cartesian grids, and boundary element method is applied to each element. Discrete fractures are flexibly handled by embedding the fractures into the background grids for the domain, and finite difference method is applied to model flow within the fracture system. The flow between the fracture system and matrix system is coupled to obtain the eventual matrix equation, and Picard successive approximation method is applied to obtain the solution of the nonlinear system. The solution of the novel Green element method is validated by the commercial simulator Eclipse for a fractured tight gas well model. A field case from Longmaxi formation in Southwestern China is used to verify the utility of the model. Moreover, the effects of nonlinear parameters on the performance of the well are analyzed. The results show that the nonlinear factors in shale gas flow model have a great impact on the eventual results of gas production forecasts, especially gas PVT properties and stress-sensitive fracture conductivity.Cheng, Y., Li, S.-M., Liggio, J., Gordon, M., Darlington, A., Zheng, Q., Moran, M., Liu, P., Wolde, M., 2020. Top-down determination of black carbon emissions from oil sand facilities in Alberta, Canada using aircraft measurements. Environmental Science & Technology 54, 412-418. carbon (BC) emissions from the Canadian oil sand (OS) surface mining facilities in Alberta were investigated using aircraft measurements. BC emission rates were derived with a top-down mass balance approach and were found to be linearly related to the volume of oil sand ore mined at each facility. Two emission factors were determined from the measurements; production-based BC emission factors were in the range of 0.6–1.7 g/tonne mined OS ore, whereas fuel-based BC emission factors were between 95 and 190 mg/kg-fuel, depending upon the facility. The annual BC emission, at 707 ± 117 tonnes/year for the facilities, was determined using the production-based emission factors and annual production data. Although this annual emission is in reasonable agreement with the BC annual emissions reported in the latest version of the Canadian national BC inventory (within 16%), the relative split between off-road diesel and stack sources is significantly different between the measurements and the inventory. This measurement evidence highlights the fact that the stack sources of BC may be overestimated and the off-road diesel sources may be underestimated in the inventory and points to the need for improved BC emission data from diesel sources within facilities.Chiu, H.-H., Kuo, C.-H., 2020. Gas chromatography-mass spectrometry-based analytical strategies for fatty acid analysis in biological samples. Journal of Food and Drug Analysis 28, 60-73. acids play critical roles in biological systems. Imbalances in fatty acids are related to a variety of diseases, which makes the measurement of fatty acids in biological samples important. Many analytical strategies have been developed to investigate fatty acids in various biological samples. Due to the structural diversity of fatty acids, many factors need to be considered when developing analytical methods including extraction methods, derivatization methods, column selections, and internal standard selections. This review focused on gas chromatography-mass spectrometry (GC–MS)-based methods. We reviewed several commonly used fatty acid extraction approaches, including liquid–liquid extraction and solid-phase microextraction. Moreover, both acid and base derivatization methods and other specially designed methods were comprehensively reviewed, and their strengths and limitations were discussed. Having good separation efficiency is essential to building an accurate and reliable GC–MS platform for fatty acid analysis. We reviewed the separation performance of different columns and discussed the application of multidimensional GC for improving separations. The selection of internal standards was also discussed. In the final section, we introduced several biomedical studies that measured fatty acid levels in different sample matrices and provided hints on the relationships between fatty acid imbalances and diseases.Chon-Torres, O.A., 2020. Astrobioethics: a brief discussion from the epistemological, religious and societal dimension. International Journal of Astrobiology 19, 61-67. astrobiology progresses in its quest to discover life on other planets or to put ourselves in another one, so does its moral problematic. Astrobiology is not only part of natural sciences, but also deals with direct aspects of humanities. For this reason, this paper aims to briefly examine astrobioethics from the epistemological, religious and societal dimension. It also deals with different researches in this regard, in order to better understand the state of the art on this topic and that astrobioethics can help us not only on how we should relate with extraterrestrial lifeforms, but even with terrestrials.Chon-Torres, O.A., 2020. Moral challenges of going to Mars under the presence of non-intelligent life scenario. International Journal of Astrobiology 19, 49-52. is discussed what would be the ideal position in terms of our ethical treatment with respect to other forms of life, particularly those that can be discovered in other worlds, in addition to our role in terms of the expansion of terrestrial life in the universe. This represents a great philosophical challenge, but what if we should make a moral decision in the face of the inevitable situation of being forced to colonize, for example, Mars? Is there a position in which we can feel safe to act legitimately? This paper tries to force us into a mental and conceptual exercise about what can really be worth beyond the concept or the positions we may have and analyse them in light of the practicality that decision making requires in this problem.Choudhary, N., Narayanan Nair, A.K., Che Ruslan, M.F.A., Sun, S., 2019. Bulk and interfacial properties of decane in the presence of carbon dioxide, methane, and their mixture. Scientific Reports 9, 19784. dynamics simulations were performed to study the bulk and interfacial properties of methane?+?n-decane, carbon dioxide?+?n-decane, and methane?+?carbon dioxide?+?n-decane systems under geological conditions. In addition, theoretical calculations using the predictive Peng-Robinson equation of state and density gradient theory are carried out to compare with the simulation data. A key finding is the preferential dissolution in the decane-rich phase and adsorption at the interface for carbon dioxide from the methane/carbon dioxide mixture. In general, both the gas solubility and the swelling factor increase with increasing pressure and decreasing temperature. Interestingly, the methane solubility and the swelling of the methane?+?n-decane system are not strongly influenced by temperature. Our results also show that the presence of methane increases the interfacial tension (IFT) of the carbon dioxide?+?n-decane system. Typically, the IFT of the studied systems decreases with increasing pressure and temperature. The relatively higher surface excess of the carbon dioxide?+?n-decane system results in a steeper decrease in its IFT as a function of pressure. Such systematic investigations may help to understand the behavior of the carbon dioxide-oil system in the presence of impurities such as methane for the design and operation of carbon capture and storage and enhanced oil recovery processes.Ci, X., Zhang, H., Niu, Q., Zhu, D., Kang, S., Hu, J., Zhang, L., Zhang, J., He, K., 2019. Analysis of tight oil and gas charging characteristics by the carbon isotope field detection technology:A case study of the northern slope of the Minfeng sub-sag in the Bohai Bay Basin. Natural Gas Industry 39, 10-17. Chinese. Studying hydrocarbon charging is quite important for searching exploration targets and confirming well locations. In this paper, the north slope of the Minfeng sub-sag in the Bohai Bay Basin was taken as an example. The wells Yanxie 233, Yongxie 932 and Yan 22 were selected for on-site carbon isotope detection. Then, based on sufficient carbon isotope data which were acquired on the drilling site using the brand-new carbon isotopic measuring instrument, the carbon isotope data and composition data of natural gas produced in this area were compared. And combined with the evolution of source rocks, the geochemical characteristics of crude oil, the depositional environment of reservoirs and the physical properties, single-well charging characteristics and regional charging area of natural gas were analyzed. Finally, the feasibility of on-site carbon isotope detection method to discriminate hydrocarbon charging was discussed. And the following research results were obtained. First, deep hydrocarbon charging happened in the lower fourth Member of Shahejie Formation in Well Yanxie 233, and its natural gas is the mixture of the oil cracking gas of deep layers and the thermal cracking gas of autochthonous source rocks. Second, the natural gas in the third and fourth Members of Shahejie Formation in Well Yongxie 932 is the thermal cracking gas of autochthonous source rocks, but deep gas charging occurred in particular hole sections. Third, the carbon isotope of associated gas in Well block Yan 22 is high in the central area and low in both sides and high in the south and low in the north, which is accordant with the distribution characteristics of reservoir physical properties, indicating that the charging of high-maturity natural gas is under the control of reservoir physical properties. Fourth, the oil in Well block Yan 22 is the product of autochthonous source rocks in the mature stage while the natural gas is the autochthonous oil-associated gas combined with the charging of deep high-maturity product. It is concluded that there is a high-maturity hydrocarbon charging area in the northwest of the northern slope of the Minfeng sub-sag, and it is a favorable hydrocarbon exploration target. What’s more, the on-site carbon isotope rapid detection technology can provide a large number of continuous three-dimensional carbon isotope data, and it can be used to quickly analyze the characteristics of hydrocarbon charging and determine the source and origin of hydrocarbon, so as to provide reference for hydrocarbon development deployment.Cierniak, D., Wo?niak-Karczewska, M., Parus, A., Wyrwas, B., Loibner, A.P., Heipieper, H.J., ?awniczak, ?., Chrzanowski, ?., 2020. How to accurately assess surfactant biodegradation-impact of sorption on the validity of results. Applied Microbiology and Biotechnology 104, 1-12. not only are widely used in biotechnological processes but also constitute significant contaminants of the modern world. Among many reports, there is a shortage of works which summarize the issue of surfactant sorption to biomass in a way that would elucidate the biological factors for analysts and analytical factors for microbiologists. The main factor, which is not as obvious as one would expect, is associated with the susceptibility of analytical approaches to errors resulting from incorrect handling of biomass. In case of several publications reviewed in the framework of this study, it was not possible to establish whether the decrease of the analytical signal observed by the authors actually resulted from biodegradation of the surfactant. This review emphasizes the necessity to consider the possibility of surfactant sorption to microbial cells, which may result in significant detection errors as well as conceptual inconsistency. In addition, a reference study regarding representative surfactants (cationic, anionic and non-ionic) as well as yeast, Gram-negative, Gram-positive bacteria, and activated sludge was provided to highlight the possible errors which may arise from disregarding sorption processes when determining degradation of surfactants. This particularly applies to systems which include ionic surfactants and activated sludge as sorption may account for 90% of the observed depletion of the surfactant. Therefore, a systematic approach was proposed in order to improve the credibility of the obtained results. Finally, the need to employ additional procedures was highlighted which may be required in order to verify that the decrease of surfactant concentration results from biodegradation processes.Cisneros-Dévora, R., Nieto-?lvarez, D.A., Cerón-Camacho, R., Pérez-?lvarez, M., Cartas-Rosado, A.R., Oviedo-Roa, R., Martínez-Magadán, J.M., Zamudio-Rivera, L.S., Pons-Jiménez, M., Hernández-Altamirano, R., Mena-Cervantes, V.Y., 2020. Molecular modeling, synthesis and characterization of branched geminal zwitterionic liquids for enhanced oil recovery. Arabian Journal of Chemistry 12, 4212-4219. Sulfobetaine-based Branched Geminal Zwitterionic Liquid (SBGZL) and another one based in hydroxysultaine (HBGZL), were synthesized and their performance evaluated in the enhancement of the oil recovery (EOR) when they are injected through flooding water into carbonate reservoirs. SBGZL obtained 39.4 % and 215.5% more recovery factor for light- and heavy-oil, respectively, than the obtained by a synthetic brine used as a reference; conversely, HBGZL obtained 37.5% and 44.7%, respectively. Density-Functional-Theory calculations of interaction energies reveal that both the SBGZL and HBGZL molecules adsorb on the carbonate surfaces stronger than an asphaltene molecule, implying that the good EOR performance of the zwitterionic liquids is due to the induced wettability change of the firstly-oil-wet carbonate surfaces.Coffinet, S., Meador, T.B., Mühlena, L., Becker, K.W., Schr?der, J., Zhu, Q.-Z., Lipp, J.S., Heuer, V.B., Crump, M.P., Hinrichs, K.-U., 2020. Structural elucidation and environmental distributions of butanetriol and pentanetriol dialkyl glycerol tetraethers (BDGTs and PDGTs). Biogeosciences 17, 317-330. and pentanetriol dialkyl glycerol tetraethers (BDGTs and PDGTs) are membrane lipids, recently discovered in sedimentary environments and in the methanogenic archaeon Methanomassiliicoccus luminyensis. They possess an unusual structure, which challenges fundamental assumptions in lipid biochemistry. Indeed, they bear a butanetriol or a pentanetriol backbone instead of a glycerol at one end of their core structure. In this study, we unambiguously located the additional methyl group of the BDGT compound on the C3 carbon of the lipid backbone via high-field nuclear magnetic resonance (NMR) experiments. We further systematically explored the abundance, distribution and isotopic composition of BDGTs and PDGTs as both intact polar and core lipid forms in marine sediments collected in contrasting environments of the Mediterranean Sea and Black Sea. High proportions of intact polar BDGTs and PDGTs in the deeper methane-laden sedimentary layers and relatively 13C-depleted BDGTs, especially in the Rhone Delta and in the Black Sea, are in agreement with a probable methanogenic source for these lipids. However, contributions from heterotrophic Archaea to BDGTs (and PDGTs) cannot be excluded, particularly in the eastern Mediterranean Sea, and contrasting BDGT and PDGT headgroup distribution patterns were observed between the different sites studied. This points to additional, non-methanogenic, archaeal sources for these lipids.Cojoc, L.R., Enache, M.I., Neagu, S.E., Lungulescu, M., Setnescu, R., Ruginescu, R., Gomoiu, I., 2019. Carotenoids produced by halophilic bacterial strains on mural paintings and laboratory conditions. FEMS Microbiology Letters 366, fnz243. to the presence of efflorescences and improper microclimate conditions for conservation, pink-pigmented areas were reported in two historic monuments in Northern and Central part of Romania. The aims of the present study were to find the nature of pink pigments observed on the pictorial layer, original and infilling mortar, to investigate the presence of carotenoids both on mural paintings and in the isolated halophilic bacterial strains and to preliminary characterize and identify the producing strains. Their role in the aesthetical biodeterioration of historic monuments was also pointed out. Obtained Raman spectra of the pink pigments extracted both from the isolated bacterial cultures (molecularly identified as mostly related to Halobacillus hunanensis and Halobacillus naozhouensis) and from the mural painting samples contain diagnostic bands of carotenoids. These results were confirmed by FTIR spectroscopy. The strong Raman signal of bacterial carotenoids detected on mural painting indicated their potential use as biomarker molecules in the evaluation of contamination and state of conservation of mural paintings and lithic monuments. Our results contribute to opening a new direction in cultural heritage restoration to assess the conservation status on the basis of interdisciplinary research, starting with spectroscopic methods (Raman, FTIR) and confirmed by microbiological analysis.Colby, S.M., Nu?ez, J.R., Hodas, N.O., Corley, C.D., Renslow, R.R., 2020. Deep learning to generate in silico chemical property libraries and candidate molecules for small molecule identification in complex samples. Analytical Chemistry 92, 1720-1729. and unambiguous identification of small molecules in complex samples will revolutionize our understanding of the role of metabolites in biological systems. Existing and emerging technologies have enabled measurement of chemical properties of molecules in complex mixtures and, in concert, are sensitive enough to resolve even stereoisomers. Despite these experimental advances, small molecule identification is inhibited by (i) chemical reference libraries (e.g., mass spectra, collision cross section, and other measurable property libraries) representing <1% of known molecules, limiting the number of possible identifications, and (ii) the lack of a method to generate candidate matches directly from experimental features (i.e., without a library). To this end, we developed a variational autoencoder (VAE) to learn a continuous numerical, or latent, representation of molecular structure to expand reference libraries for small molecule identification. We extended the VAE to include a chemical property decoder, trained as a multitask network, in order to shape the latent representation such that it assembles according to desired chemical properties. The approach is unique in its application to metabolomics and small molecule identification, with its focus on properties that can be obtained from experimental measurements (m/z, CCS) paired with its training paradigm, which involved a cascade of transfer learning iterations. First, molecular representation is learned from a large data set of structures with m/z labels. Next, in silico property values are used to continue training, as experimental property data is limited. Finally, the network is further refined by being trained with the experimental data. This allows the network to learn as much as possible at each stage, enabling success with progressively smaller data sets without overfitting. Once trained, the network can be used to predict chemical properties directly from structure, as well as generate candidate structures with desired chemical properties. Our approach is orders of magnitude faster than first-principles simulation for CCS property prediction. Additionally, the ability to generate novel molecules along manifolds, defined by chemical property analogues, positions DarkChem as highly useful in a number of application areas, including metabolomics and small molecule identification, drug discovery and design, chemical forensics, and beyond.Collini, H., Li, S., Jackson, M.D., Agenet, N., Rashid, B., Couves, J., 2020. Zeta potential in intact carbonates at reservoir conditions and its impact on oil recovery during controlled salinity waterflooding. Fuel 266, 116927. is well known that oil recovery from carbonate reservoirs can be increased by modifying the injected brine composition in a process ‘controlled salinity water-flooding’ (CSW). However, the mineral- to pore- scale processes responsible for improved oil recovery (IOR) during CSW remain ambiguous and there is no method to predict the optimum CSW composition for a given crude-oil-brine rock system. Here we report the first integrated experimental measurements of zeta potential and IOR during CSW obtained at reservoir conditions. The zeta potential is a measure of the electrical potential at mineral-brine and oil-brine interfaces and controls the electrostatic forces acting between these interfaces.We find that the measured zeta potential in clean samples saturated with formation brine is typically positive and becomes more negative with brine dilution irrespective of temperature. After aging and wettability alteration, the zeta potential changes and we suggest a more positive zeta potential indicates a positive zeta potential at the oil-brine interface and vice-versa. Injecting low salinity brine yields IOR when the oil-brine zeta potential is identified to be negative, but no response when it is identified to be positive, consistent with the hypothesis that IOR during CSW is caused by an increase in the repulsive electrostatic force acting between mineral-brine and oil-brine interfaces. We suggest that the optimum brine composition for IOR during CSW should be chosen to yield the largest change in zeta potential at the mineral-brine interface with opposing polarity to the oil-brine interface and can be determined using the experimental method reported here.Contador, C.A., Veas-Castillo, L., Tapia, E., Antipán, M., Miranda, N., Ruiz-Tagle, B., García-Araya, J., Andrews, B.A., Marin, M., Dorador, C., Asenjo, J.A., 2020. Atacama Database: a platform of the microbiome of the Atacama Desert. Antonie van Leeuwenhoek 113, 185-195. Atacama Desert is one of the oldest and driest places on Earth. In the last decade, microbial richness and diversity has been acknowledged as an important biological resource of this region. Owing to the value of the microbial diversity apparent in potential biotechnology applications and conservation purposes, it is necessary to catalogue these microbial communities to promote research activities and help to preserve the wide range of ecological niches of the Atacama region. A prototype Atacama Database has been designed and it provides a description of the rich microbial diversity of the Atacama Desert, and helps to visualise available literature resources. Data has been collected, curated, and organised into several categories to generate a single record for each organism in the database that covers classification, isolation metadata, morphology, physiology, genome and metabolism information. The current version of Atacama Database contains 2302 microorganisms and includes cultured and uncultured organisms retrieved from different environments within the desert between 1984 and 2016. These organisms are distributed in bacterial, archaeal or eukaryotic domains, along with those that are unclassified taxonomically. The initial prototype of the Atacama Database includes a basic search and taxonomic and advanced search tools to allow identification and comparison of microbial populations, and space distribution within this biome. A geolocation search was implemented to visualise the microbial diversity of the ecological niches defined by sectors and extract general information of the sampling sites. This effort will aid understanding of the microbial ecology of the desert, microbial population dynamics, seasonal behaviour, impact of climate change over time, and reveal further biotechnological applications of these microorganisms. The Atacama Database is freely available at: , A., Birgel, D., Kappler, A., Peckmann, J., 2020. Carbon stable isotope patterns of cyclic terpenoids: A comparison of cultured alkaliphilic aerobic methanotrophic bacteria and methane-seep environments. Organic Geochemistry 139, 103940. methanotrophic bacteria are known to synthesize a variety of cyclic terpenoids which are typified by 13C-depleted, methane-derived carbon. This peculiarity facilitates identification of methanotroph biomarkers in natural samples. However, the current biomarker database does not always allow biomarker patterns of marine samples to be assigned to the different types of aerobic methanotrophs. To overcome this shortcoming, the carbon stable isotope composition of cyclic terpenoids of two strains of the Type I methanotroph genus Methylomicrobium was analyzed. Other than aerobic methanotrophs used for biomarker studies in the past, these two strains deriving from soda lake environments are able to tolerate the conditions typifying marine environments including high alkalinity and salinity. The cyclic terpenoid inventory of the two strains comprises 4-methyl steroids, 3-methyl- and desmethyl bacteriohopanepolyols (aminotetrol and aminotriol), and tetrahymanol, all of which are 13C-depleted. The average carbon isotope fractionation between methane and the respective lipid (Δδ13Cterpenoid-methane) is found to be ?25‰ for M. kenyense and ?16‰ for M. alcaliphilum. These data shed new light on the previously reported compound and carbon stable isotope patterns of cyclic terpenoids from methane-seep environments. Particularly, 13C-depleted tetrahymanol and gammacerane are reinterpreted as biomarkers of aerobic methanotrophic bacteria based on their occurrence in methane-seep deposits in association with other biomarkers of aerobic methanotrophs. The use of δ13C values of anaerobic methane-oxidizing archaea (ANME) lipids for the reconstruction of the isotopic composition of parent methane allows us to calculate the Δδ13Cterpenoid-methane even for ancient seep environments. With this calculation, Type I and Type II methanotrophs can be discriminated, representing a new approach to better characterize past methanotrophy at seeps and possibly other marine environments.Cours, T., Cordier, D., Seignovert, B., Maltagliati, L., Biennier, L., 2020. The 3.4 μm absorption in Titan’s stratosphere: Contribution of ethane, propane, butane and complex hydrogenated organics. Icarus 339, 113571. complex organic chemistry harbored by the atmosphere of Titan has been investigated in depth by Cassini observations. Among them, a series of solar occultations performed by the VIMS instrument throughout the 13 years of Cassini revealed a strong absorption centered at ～3.4 μm. Several molecules present in Titan’s atmosphere generate spectral features in that wavelength region, but their individual contributions are difficult to disentangle. In this work, we quantify the contribution of the various molecular species to the 3.4μm band using a radiative transfer model. Ethane and propane are significant components of the band but they are insufficient to reproduce perfectly its shape. Polycyclic Aromatic Hydrocarbons (PAHs) and more complex polyaromatic hydrocarbons like Hydrogenated Amorphous Carbons (HACs) are the most plausible candidates because they are rich in C-H bonds. PAHs signature have already been detected above ～900 km, and they are recognized as precursors of aerosol particles. High similarities between individual spectra impede the derivation of abundances.Cousins, C.R., Mikhail, S., Foucher, F., Steele, A., Westall, F., 2020. Metamorphic evolution of carbonate-hosted microbial biosignatures. Geochemical Perspectives Letters 12, 40-45. biosignature assemblages captured within mineral substrates experience extreme pressures (P) and temperatures (T) during rock burial and metamorphism. We subjected natural microbial biofilms hosted within thermal spring carbonate to six high pressure, high temperature (HPHT) conditions spanning 500 and 800 MPa and 200 to 550 °C, to investigate the initial petrographic transformation of organic and inorganic phases. We find biogenic and amorphous silica mineralises increasingly mature organic matter (OM) as temperature and pressure increase, with OM expelled from recrystallised calcite at the highest HPHT, captured within a quartz phase. Sulfur globules associated with microbial filaments persist across all HPHT conditions in association with microbially-derived kerogen. These data demonstrate how microbial material captured within chemically-precipitated sediments petrographically evolves in high grade rocks during their first stages of transformation.Cowart, D.A., Matabos, M., Brandt, M.I., Marticorena, J., Sarrazin, J., 2020. Exploring environmental DNA (eDNA) to assess biodiversity of hard substratum faunal communities on the Lucky Strike Vent Field (Mid-Atlantic Ridge) and investigate recolonization dynamics after an induced disturbance. Frontiers in Marine Science 6, 783. doi: 10.3389/fmars.2019. 00783. ocean hydrothermal vent ecosystems face physical disturbances from naturally occurring volcanic and tectonic activities and are at increasing risk of mineral resource exploitation, raising concerns about the resilience of endemic biological communities. Following destructive events, efficient and rapidly applicable surveys of organisms are required to monitor the state, evolution and a possible return of these ecosystems to their original baseline status. In this study, we explored the environmental DNA (eDNA) approach as a tool (1) to assess biodiversity of benthic communities associated with deep-sea hard substrata and (2) tracked the recolonization dynamics of benthic invertebrate communities living on the Montségur edifice within the Lucky Strike vent field (Mid-Atlantic Ridge), after an induced disturbance that consisted of faunal clearance within experimental quadrats. Hard substratum samples were collected prior to and one year after the disturbance, for eDNA metabarcoding using one marker of the mitochondrial Cytochrome Oxidase I (COI) gene and three markers of the nuclear 18S ribosomal RNA (18S) gene. We also generated a DNA barcoding inventory that consisted of taxa physically collected from Montségur and morphologically identified. This inventory contained amplified barcodes from COI, 18S and the nuclear large subunit ribosomal RNA (28S) gene. The resulting sequence information from the COI and 18S were used for eDNA taxonomic assignment. The eDNA datasets uncovered a high diversity of metazoan OTUs, which included macro- and meiofauna common to Lucky Strike. Baseline data collected at the start of the experiment identified higher OTU richness at sites peripheral to the active edifice, as well as at inactive sites. One year following the initial disturbance, analysis of recolonization data found no statistical difference in presence/absence from baseline communities. The eDNA protocols provide a reproducible strategy to quickly assess biodiversity associated with deep sea hard substratum, enabling comparisons across various habitats. To follow recolonization dynamics at small spatial scales, however, we recommend an approach that uses both molecular and morphological-based traditional methods. Finally, we present original data on the “unseen” diversity of the fauna inhabiting the poorly studied inactive sites, locations that are targeted by commercial mining. Continued monitoring of these sites is currently ongoing and will bring new insight on recovery potential over time, with the ultimate goal of informing conservation and management decisions in relation to the protection of hydrothermal vent ecosystems.Cribb, A.T., Bottjer, D.J., 2020. Complex marine bioturbation ecosystem engineering behaviors persisted in the wake of the end-Permian mass extinction. Scientific Reports 10, 203. end-Permian mass extinction was the most severe mass extinction event of the Phanerozoic and was followed by a several million-year delay in benthic ecosystem recovery. While much work has been done to understand biotic recovery in both the body and trace fossil records of the Early Triassic, almost no focus has previously been given to analyzing patterns in ecosystem engineering complexity as a result of the extinction drivers. Bioturbation is a key ecosystem engineering behavior in marine environments, as it results in changes to resource flows and the physical environment. Thus, the trace fossil record can be used to examine the effect of the end-Permian mass extinction on bioturbating ecosystem engineers. We present a dataset compiled from previously published literature to analyze burrowing ecosystem engineering behaviors through the Permian-Triassic boundary. We report two key observations: first, that there is no loss in bioturbation ecosystem engineering behaviors after the mass extinction, and second, that these persisting behaviors include deep tier, high-impact, complex ecosystem engineering. These findings suggest that while environmental conditions may have limited deeper burrowing, complex ecosystem engineering behaviors were able to persist in the Early Triassic. Furthermore, the persistence of deep tier bioirrigated three-dimensional network burrows implies that benthic biogeochemical cycling could have been maintained at pre-extinction states in some local environments, stimulating ecosystem productivity and promoting biotic recovery in the Early Triassic.Crucello, J., Pierone, D.V., Hantao, L.W., 2020. Simple and cost-effective determination of polychlorinated biphenyls in insulating oils using an ionic liquid-based stationary phase and flow modulated comprehensive two-dimensional gas chromatography with electron capture detection. Journal of Chromatography A 1610, 460530. this article we describe a method using flow-modulated comprehensive two-dimensional gas chromatography with electron capture detector (FM–GC×GC–ECD) for the determination of polychlorinated biphenyls (PCBs) in complex transformer oils bypassing the need for sample preparation. A two-fold improvement in method development was attained. First, the solvation parameter model (SPM) was used to guide column selection. A highly cohesive ionic liquid-based phase (low l system constant), namely 1,12-di(tripropylphosphonium)dodecane bis(trifluoromethanesulfonyl)imide, was used in the primary stage leading to negligible retention of interfering aliphatic hydrocarbons, which are eluted in the first upper quadrant of the chromatogram. The resulting separation space was used to resolve the critical class of compounds, namely, PCBs and polyaromatic hydrocarbons. Second, a unique combination of column geometries and phase ratios enabled highly efficient reverse fill/flush flow modulation using very low pressure for auxiliary gas flow. The proof of concept method described herein exhibited linearities ranging from 0.990 to 0.994, limits of quantitation (LOQ) from 2.23 and 6.85??g?mL?1, precision below 5% relative standard deviation (RSD), and accuracy from 84.2% to 108.9% showcasing the potential of FM–GC×GC for routine analysis.Cui, L., Liu, W., Zhang, X., 2020. Phosphatized microbial fossils from the lowest Cambrian of South China and their ecological and environmental implications for the Kuanchuanpu biota. Precambrian Research 338, 105560. early Cambrian Fortunian-age Kuanchuanpu Formation exposed in the northwestern margin of South China is well known for recording unique aspects of the “Cambrian explosion”, notably the coexistence of Small Shelly Faunas and soft-bodied meiofaunas. Although microorganisms, both primary producers and decomposers, are important biotic components of marine ecosystems in which they play a crucial ecological role in matter cycling and energy flow, Cambrian microbial records have not been brought into attention so much as their intimately associated faunas. To extend these records here we report a diverse assemblage of cellularly preserved microbial fossils from cherts of the Kuanchuanpu Formation. Nine species comprising six genera and two undescribed taxa have been identified. Among taxa interpreted as primary producers, are Gloeodiniopsis and unnamed form B that are morphologically analogous to coccoidal chroococcacean cyanobacteria, and Megathrix and Siphonophycus to filamentous oscillatoriacean cyanobacteria. In contrast, co-occurring members of endobiotic Endoconchia ? are inferred to be biodegraders. The high preservational fidelity of this microbial assemblage is here documented by use of optical microscopy, scanning electron microscopy, energy dispersive spectrometry, back-scattered electron microscopy and Raman spectroscopy. These analyses results demonstrate that the microbial fossils were organic remains (Kerogen) permineralized by pre-decay phosphatization and then sealed within the encompassing siliceous matrix. This mode of fossilization differs from typical chert-embedded silica-permineralized Proterozoic microfossils in the presence of apatite permineralization, which is regarded as a response to the phosphogenic event during the Neoproterozoic-Cambrian transition.Culka, A., Ko?ek, F., Oren, A., Mana, L., Jehli?ka, J., 2019. Detection of carotenoids of halophilic prokaryotes in solid inclusions inside laboratory-grown chloride and sulfate crystals using a portable Raman spectrometer: applications for Mars exploration. FEMS Microbiology Letters 366, fnz239. in evaporitic minerals sometimes contain remnants of microorganisms or biomarkers, which can be considered as traces of life. Raman spectroscopy with resonance enhancement is one of the best analytical methods to search for such biomarkers in places of interest for astrobiology, including the surface and near subsurface of planet Mars. Portable Raman spectrometers are used as training tools for detection of biomarkers. Investigations of the limits and challenges of detecting biomolecules in crystals using Raman spectroscopy is important because natural occurrences often involve mineral assemblages as well as their fluid and solid inclusions. A portable Raman spectrometer with 532 nm excitation was used for detection of carotenoid biomarkers: salinixanthin of Salinibacter ruber (Bacteroidetes) and α-bacterioruberin of Halorubrum sodomense (Halobacteria) in laboratory-grown artificial inclusions in compound crystals of several chlorides and sulfates, simulating entrapment of microorganisms in evaporitic minerals. Crystals of halite (NaCl), sylvite (KCl), arcanite (K2SO4) and tschermigite ((NH4)Al(SO4)2·12H2O) were grown from synthetic solutions that contained microorganisms. A second crystalline layer of NaCl or K2SO4 was grown subsequently so that primary crystals containing microorganisms are considered as solid inclusions. A portable Raman spectrometer with resonance enabling excitation detected signals of both carotenoid pigments. Correct positions of diagnostic Raman bands corresponding to the specific carotenoids were recorded.Dai, S., Bechtel, A., Eble, C.F., Flores, R.M., French, D., Graham, I.T., Hood, M.M., Hower, J.C., Korasidis, V.A., Moore, T.A., Püttmann, W., Wei, Q., Zhao, L., O'Keefe, J.M.K., 2020. Recognition of peat depositional environments in coal: A review. International Journal of Coal Geology 219, 103383. depositional environments, the sites where and conditions under which peat accumulates, significantly influence a resultant coal's physical properties, chemical composition, and coal utilization behavior. Recognition of peat depositional environments for coal is a challenging endeavor because coal's observed compositional properties not only result from a variety of geological processes operating during peat accumulation, but also reflect the influence of adjoining or external depositional sedimentary environments and alteration during later diagenesis and/or epigenesis. The maceral or microlithotype composition of any one layer of peat can be the product of years or decades of plant growth, death, decay, and post-burial infiltration by roots in addition to the symbiotic, mutualistic, parasitic, and saprophytic relationships with non-plant biota, such as arthropods, fungi, and bacteria. The overprint of increasing thermal maturation and fluid migration through time on the resulting coal can make these relationships difficult to recognize. Therefore, published models based on maceral composition alone must be used with great caution. Lipid compositions, even from lipid-poor low-rank coals, can provide important information about depositional environments and paleoclimate, especially if combined with the results of organic petrography and paleontological studies. Just as sulfur derived from seawater provides environmental clues, the ratios of two particularly relevant trace elements rather than a single trace element can be used to interpret peat depositional environments. Epigenetic minerals, as well as their corresponding chemical compositions should not be used for such a purpose; similarly, resistant terrigenous minerals deposited during peat accumulation in many cases should be used with considerable caution. The interactions of the biota present in the peat-forming ecosystem, often determined using palynological and geochemical proxies, and their interpretation in the context of geography and paleoclimate are important means for deciphering peat depositional environments. Overall, a combination of evidence from geochemistry, mineralogy, palynology, and petrology of coal and from stratigraphy, sedimentology, and sedimentary facies of related rocks is necessary for accurate and comprehensive determination of depositional environments. The need for interdisciplinary studies is underscored by peat compositional properties, which have been greatly affected by various processes during the syngenetic, diagenetic or epigenetic stages of coal formation.DasSarma, S., DasSarma, P., Laye, V.J., Schwieterman, E.W., 2020. Extremophilic models for astrobiology: haloarchaeal survival strategies and pigments for remote sensing. Extremophiles 24, 31-41. progress in extremophile biology, exploration of planetary bodies in the solar system, and the detection and characterization of extrasolar planets are leading to new insights in the field of astrobiology and possible distribution of life in the universe. Among the many extremophiles on Earth, the halophilic Archaea (Haloarchaea) are especially attractive models for astrobiology, being evolutionarily ancient and physiologically versatile, potentially surviving in a variety of planetary environments and with relevance for in situ life detection. Haloarchaea are polyextremophilic with tolerance of saturating salinity, anaerobic conditions, high levels of ultraviolet and ionizing radiation, subzero temperatures, desiccation, and toxic ions. Haloarchaea survive launches into Earth’s stratosphere encountering conditions similar to those found on the surface of Mars. Studies of their unique proteins are revealing mechanisms permitting activity and function in high ionic strength, perchlorates, and subzero temperatures. Haloarchaea also produce spectacular blooms visible from space due to synthesis of red–orange isoprenoid carotenoids used for photoprotection and photorepair processes and purple retinal chromoproteins for phototrophy and phototaxis. Remote sensing using visible and infrared spectroscopy has shown that haloarchaeal pigments exhibit both a?discernable peak of absorption and a reflective?“green edge”. Since the pigments produce remotely detectable features, they may influence the spectrum from an inhabited exoplanet imaged by a future large space-based telescope. In this review, we focus primarily on studies of two Haloarchaea, Halobacterium sp. NRC-1 and Halorubrum lacusprofundi.de Carvalho, J.C., Magalh?es, A.I., de Melo Pereira, G.V., Medeiros, A.B.P., Sydney, E.B., Rodrigues, C., Aulestia, D.T.M., de Souza Vandenberghe, L.P., Soccol, V.T., Soccol, C.R., 2020. Microalgal biomass pretreatment for integrated processing into biofuels, food, and feed. Bioresource Technology 300, 122719. are sources of nutritional products and biofuels. However, their economical processing is challenging, because of (i) the inherently low concentration of biomass in algal cultures, below 0.5%, (ii) the high-water content in the harvested biomass, above 70%; and (iii) the variable intracellular content and composition. Cell wall structure and strength vary enormously among microalgae, from naked Dunaliella cells to robust Haematococcus cysts. High-value products justify using fast and energy-intensive processes, ranging from 0.23 kWh/kg dry biomass in high-pressure homogenization, to 6 kWh/kg dry biomass in sonication. However, in biofuels production, the energy input must be minimized, requiring slower, thermal or chemical pretreatments. Whichever the primary fraction of interest, the spent biomass can be processed into valuable by-products. This review discusses microalgal cell structure and composition, how it affects pretreatment, focusing on technologies tested for large scale or promising for industrial processes, and how these can be integrated into algal biorefineries.de Gouw, J.A., Veefkind, J.P., Roosenbrand, E., Dix, B., Lin, J.C., Landgraf, J., Levelt, P.F., 2020. Daily satellite observations of methane from oil and gas production regions in the United States. Scientific Reports 10, 1379. of oil and natural gas in North America is at an all-time high due to the development and use of horizontal drilling and hydraulic fracturing. Methane emissions associated with this industrial activity are a concern because of the contribution to climate radiative forcing. We present new measurements from the space-based TROPOspheric Monitoring Instrument (TROPOMI) launched in 2017 that show methane enhancements over production regions in the United States. In the Uintah Basin in Utah, TROPOMI methane columns correlated with in-situ measurements, and the highest columns were observed over the deepest parts of the basin, consistent with the accumulation of emissions underneath inversions. In the Permian Basin in Texas and New Mexico, methane columns showed maxima over regions with the highest natural gas production and were correlated with nitrogen-dioxide columns at a ratio that is consistent with results from in-situ airborne measurements. The improved detail provided by TROPOMI will likely enable the timely monitoring from space of methane emissions associated with oil and natural gas production.de Melo, R.D., Le?o, P., Abreu, F., Acosta-Avalos, D., 2020. The swimming orientation of multicellular magnetotactic prokaryotes and uncultured magnetotactic cocci in magnetic fields similar to the geomagnetic field reveals differences in magnetotaxis between them. Antonie van Leeuwenhoek 113, 197-209. bacteria have intracellular chains of magnetic nanoparticles, conferring to their cellular body a magnetic moment that permits the alignment of their swimming trajectories to the geomagnetic field lines. That property is known as magnetotaxis and makes them suitable for the study of bacterial motion. The present paper studies the swimming trajectories of uncultured magnetotactic cocci and of the multicellular magnetotactic prokaryote ‘Candidatus Magnetoglobus multicellularis’ exposed to magnetic fields lower than 80 μT. It was assumed that the trajectories are cylindrical helixes and the axial velocity, the helix radius, the frequency and the orientation of the trajectories relative to the applied magnetic field were determined from the experimental trajectories. The results show the paramagnetic model applies well to magnetotactic cocci but not to ‘Ca. M. multicellularis’ in the low magnetic field regime analyzed. Magnetotactic cocci orient their trajectories as predicted by classical magnetotaxis but in general ‘Ca. M. multicellularis’ does not swim following the magnetic field direction, meaning that for it the inversion in the magnetic field direction represents a stimulus but the selection of the swimming direction depends on other cues or even on other mechanisms for magnetic field detection.de Oliveira, F.C., Khani, S., Maia, J.M., Tavares, F.W., 2020. Concentration and solvent effects on structural, dynamical, and rheological properties of asphaltene suspensions. Energy & Fuels 34, 1071-1081. effects of different concentrations and solvents in asphaltene solutions properties were studied using a mesoscale simulation approach named dissipative particle dynamics (DPD). Structural analysis revealed the predominance of parallel stacking between molecular planes. The time evolution of number of aggregates showed that the number of aggregates diminishes for both solvents, which makes sense as initially each aggregate represents isolated molecules. Viscosity has been calculated for all cases, and the results show that solute–solvent interactions have a great impact on the viscosity of the material, which becomes less important as the entropy becomes dominant when mass fraction increases. The viscoelastic behavior of asphaltene suspensions has been analyzed for the first using a molecular dynamics approach. All systems presented greater viscous (liquidlike) behavior under high frequencies, which is consistent with soft particles.de Sousa, J., Vencálek, O., Hron, K., Václavík, J., Friedeck?, D., Adam, T., 2020. Bayesian multiple hypotheses testing in compositional analysis of untargeted metabolomic data. Analytica Chimica Acta 1097, 49-61. metabolomics aims at finding statistically significant differences in metabolic statuses of patient and control groups with the intention of understanding pathobiochemical processes and identification of clinically useful biomarkers of particular diseases. After the raw measurements are integrated and pre-processed as intensities of chromatographic peaks, the differences between controls and patients are evaluated by both univariate and multivariate statistical methods. The traditional univariate approach relies on t-tests (or their nonparametric alternatives) and the results from multiple testing are misleadingly compared merely by p-values using the so-called volcano plot.This paper proposes a Bayesian counterpart to the widespread univariate analysis, taking into account the compositional character of a metabolome. Since each metabolome is a collection of some small-molecule metabolites in a biological material, the relative structure of metabolomic data, which is inherently contained in ratios between metabolites, is of the main interest. Therefore, a proper choice of logratio coordinates is an essential step for any statistical analysis of such data. In addition, a concept of b-values is introduced together with a Bayesian version of the volcano plot incorporating distance levels of the posterior highest density intervals from zero.The theoretical background of the contribution is illustrated using two data sets containing samples of patients suffering from 3-hydroxy-3-methylglutaryl-CoA lyase deficiency and medium-chain acyl-CoA dehydrogenase deficiency. To evaluate the stability of the proposed method as well as the benefits of the compositional approach, two simulations designed to mimic a loss of samples and a systematical measurement error, respectively, are added.Deng, X., Feng, J., Pan, S., Wang, Z., Zhang, J., Chen, W., 2020. An improved model for the migration of fluids caused by hydrate dissociation in porous media. Journal of Petroleum Science and Engineering 188, 106876. gas hydrates may be the world's future resources, but extracting from the reservoirs involves accurately understanding the transport mechanism of the fluids caused by hydrate dissociation. In this paper, based on Darcy's unsaturated soil mechanics theory, we establish a coupling model of two-phase flow and heat transfer caused by hydrate dissociation, which considering methane gas compressibility and capillary force naturally. The new model is validated through Masuda's test dataset, and notably, the experimental phenomenon of the small peak in the gas pressure of the far-end boundary (Run 4) is reproduced for the first time. Additionally, an implicit function of pore pressure and time in the initial stage of hydrate dissociation is deduced to interpret the in-situ pore accumulation of the gas generated in dissociation, which leads to a more comprehensive description of the migration mechanism of hydrate reservoir fluids. Furthermore, the initial hydrate saturation of the Run 4 sample in Masuda's test is proved to be closer to 0.501 instead of 0.443 that the author reported, which can help Masuda's test dataset being a benchmark for the hydrate dissociation researching in future. Thus, this work provides further insight into the migration mechanism of the gases caused by hydrate dissociation and services practical support for efficiently and safely extracting methane gas from the hydrate reservoirs.Deng, X., Kamal, M.S., Patil, S., Hussain, S.M.S., Zhou, X., 2020. A review on wettability alteration in carbonate rocks: Wettability modifiers. Energy & Fuels 34, 31-54. than half of the global oil reserves are in carbonate reservoirs. Carbonate rocks, however, in most cases tend to be mixed-wet or oil-wet. Wettability alteration of carbonate reservoir rock has been proven to increase oil recovery significantly. Several chemicals have shown their effect on wettability; however, selection of an appropriate wettability modifier should be made on the basis of the underlying mechanisms and their behavior at reservoir conditions. This review discusses techniques that can help in assessing wettability alteration or reflect on the underlying mechanism and describes several categories of wettability modifiers focusing on their structure–property relationship and factors affecting their performance at reservoir conditions. Surfactants, nanoparticles, salts, and alkalis are four major categories of wettability modifiers that are discussed in this review. Among surfactants, gemini surfactants have great potential and could be a major focus of future research in this area. Nanoparticles are relatively novel materials for wettability alteration with the capability to reduce contact angle significantly at low cost. This review also identifies the current and future challenges related to the performance of various wettability modifiers at high-temperature and high-salinity conditions.Dhakal, S., Gupta, I., 2020. Predictive modeling of thermogenic methane hydrate formation and geobody distribution – Results from numerical simulations. Journal of Natural Gas Science and Engineering 75, 103154. characterization of thermogenic gas hydrates have so far been limited to seismic mapping, well log interpretation, and lab scale experiments, with numerical modeling mostly focusing on gas production from hydrates. What is unknown however is the hydrate saturation at the sub-seismic and interwell scales. This study uses numerical simulations for predictive modeling of hydrate formation and geobody distribution using TOUGH?+?Hydrate. Results indicate that the flow of gas is buoyancy and advection dominated, and affects hydrate formation rate and saturation distribution. Geological controls such as fault angles, stratigraphic thickness, permeabilities and permeability anisotropies and contrasts with adjacent formations significantly impact distribution of hydrate saturation, and geobody shape. Hydrates form in both high and low porosity rocks. While full-scale reservoir modeling is contingent upon the availability of detailed reservoir and fluid data, this study underscores the importance of using numerical modeling tools for quantitative predictive modeling and reservoir characterization of hydrate reservoirs for better resource estimation, well-placement decisions, reservoir management and production planning.Dijkstra, N., Junttila, J., Aagaard-S?rensen, S., 2020. Impact of drill cutting releases on benthic foraminifera at three exploration wells drilled between 1992 and 2012 in the SW Barents Sea, Norway. Marine Pollution Bulletin 150, 110784. aim of this study is to identify the environmental impact of drill cuttings (DC) released around three wells drilled in 1992, 2000 and 2012 in the SW Barents Sea. Foraminiferal assemblages are studied in cores taken along transects <250?m from wells. Well E-1992 shows no impact of DC on foraminifera indicating that low amounts of released DC limit environmental impact. Impact at wells G-2000 and S-2012, is confined to <30?m, and attributable to smothering of fauna, resulting in low foraminiferal density. We therefore argue that previous monitoring studies, mainly focusing on samples collected >250?m from wellheads, might not capture the full impact of DC. In well G-2000, a recovery layer indicates partial recovery 15?years after DC releases. In well S-2012, no recovery is observed, 3?years after release. Released DC did not result in faunal composition changes.Ding, W., Hou, D., Jiang, L., Jiang, Y., Wu, P., 2020. High abundance of carotanes in the brackish-saline lacustrine sediments: A possible cyanobacteria source? International Journal of Coal Geology 219, 103373. organic-rich oil shales of low maturity and tight oils from the Middle Permian Lucaogou Formation were formed in a brackish-saline lacustrine environment in the Jimusaer Sag, Junggar Basin. They are characterized by remarkably abundant β-carotane and γ-carotane. The biological sources and favourable sedimentary environments of carotanes formation remain obscure. Organic geochemical analyses of 17 oil shales and 20 tight oils from the Jimusaer Sag reveal that reducing, evaporitic and carbonate-rich, shallow water environment is favourable for β-carotane accumulation. Geochemical studies show that carotane abundance is controlled by both source of organic matter and sedimentary environment rather than thermal maturity in the study area. Even though both higher plants and microalgae are reported to be precursors of carotanes, cyanobacteria may be the main biological sources of carotanes in the Lucaogou Formation based on cyanobacteria-derived biomarkers, such as the C39 2,6-dimethyl benzene-substituted isoprenoid, 2α-methylhopanes, 7- and 8-monomethylhepadecanes. The airborne volcanic ash containing ample elements (e.g. Mg and Fe) caused by the intermittent volcanic eruptions during the Middle Permian most likely contributed to the flourish of cyanobacteria in the study area.Dix, B., de Bruin, J., Roosenbrand, E., Vlemmix, T., Francoeur, C., Gorchov-Negron, A., McDonald, B., Zhizhin, M., Elvidge, C., Veefkind, P., Levelt, P., de Gouw, J., 2020. Nitrogen oxide emissions from U.S. Oil and gas production: Recent trends and source attribution. Geophysical Research Letters 47, e2019GL085866.. oil and natural gas production volumes have grown by up to 100% in key production areas between January 2017 and August 2019. Here we show that recent trends are visible from space and can be attributed to drilling, production, and gas flaring activities. By using oil and gas activity data as predictors in a multivariate regression to satellite measurements of tropospheric NO2 columns, observed changes in NO2 over time could be attributed to NOx emissions associated with drilling, production and gas flaring for three select regions: the Permian, Bakken, and Eagle Ford basins. We find that drilling had been the dominant NOx source contributing around 80% before the downturn in drilling activity in 2015. Thereafter, NOx contributions from drilling activities and combined production and flaring activities are similar. Comparison of our top‐down source attribution with a bottom‐up fuel‐based oil and gas NOx emission inventory shows agreement within error margins.Plain Language Summary: U.S. oil and natural gas production volumes have grown by up to 100% in key production areas between January 2017 and August 2019. Here we show that recent trends are visible from space as increases in NO2, an air pollutant that is released from combustion engines associated with the oil and gas industry. For three select regions, the Permian (TX and NM), Bakken (ND), and Eagle Ford (TX) basins, we report that the trend in NO2 columns over time can be explained by a combination of drilling activity, production numbers, and flared gas volume, which allows us to quantify the contributions from these sources to the total NOx (= NO + NO2) emissions from these areas. We find that drilling had been the dominant NOx source contributing around 80% before the downturn in drilling activity in 2015. But now, NOx contributions from drilling activities and combined production and flaring activities are similar. Both Permian and Bakken oil and gas production volumes are at an all‐time high and if current growth rates continue in the Eagle Ford basin, maximum production volumes will be exceeded in about 1 year.Dixon, R.A., Barros, J., 2020. Lignin biosynthesis: old roads revisited and new roads explored. Open Biology 9, 190215. is a major component of secondarily thickened plant cell walls and is considered to be the second most abundant biopolymer on the planet. At one point believed to be the product of a highly controlled polymerization procedure involving just three potential monomeric components (monolignols), it is becoming increasingly clear that the composition of lignin is quite flexible. Furthermore, the biosynthetic pathways to the major monolignols also appear to exhibit flexibility, particularly as regards the early reactions leading to the formation of caffeic acid from coumaric acid. The operation of parallel pathways to caffeic acid occurring at the level of shikimate esters or free acids may help provide robustness to the pathway under different physiological conditions. Several features of the pathway also appear to link monolignol biosynthesis to both generation and detoxification of hydrogen peroxide, one of the oxidants responsible for creating monolignol radicals for polymerization in the apoplast. Monolignol transport to the apoplast is not well understood. It may involve passive diffusion, although this may be targeted to sites of lignin initiation/polymerization by ordered complexes of both biosynthetic enzymes on the cytosolic side of the plasma membrane and structural anchoring of proteins for monolignol oxidation and polymerization on the apoplastic side. We present several hypothetical models to illustrate these ideas and stimulate further research. These are based primarily on studies in model systems, which may or may not reflect the major lignification process in forest trees.Dong, Z., Zhang, J., Tang, X., Liu, G., Dang, W., Liu, Y., Tao, J., Su, Z., 2020. Origin and diffusion of the over-mature transitional natural gas in multiple lithologic reservoirs: A case study of Carboniferous-Permian strata in the southeastern margin of Ordos Basin. International Journal of Coal Geology 219, 103380. investigate differences in gas origin and diffusion among various lithologies in the continent–marine transitional strata of the Lower Permian Shanxi Formation (P1s) and Upper Carboniferous Benxi Formation (C2b) in the southeastern margin of Ordos Basin, 31 natural gas samples were collected from the existing lithologies (including mudstone, sandstone, and coal) and their gas components and carbon and hydrogen isotope compositions were measured. Remarkable differences in the ethane (δ13C2) and carbon dioxide isotope values (δ13CCO2) within natural gas were found between the Shanxi and Benxi Formations: the δ13C2 value of natural gas in the Shanxi Formation is generally less than ?30‰, whereas that of the Benxi Formation is generally greater than ?28‰; and CO2 in the Shanxi Formation is mainly of organic origin while that in the Benxi Formation is mainly inorganic. The unusually depleted δ13C2 values found in the Shanxi Formation were caused by the addition of oil-type gas generated from the carbonate rock in the Taiyuan Formation, which resulted in partial reversal of the carbon isotope values (δ13C1 > δ13C2). However, this incorporation of oil-type gas did not occur in the Benxi Formation, which is most likely caused by the tight mudstone at the bottom of Taiyuan Formation. The differences between the Shanxi and Benxi Formations reveal that the gases in the two Formations belong to two separate gas systems, and this could be attributed to the tight mudstone and limestone existing between the reservoirs, which acts as an effective barrier preventing diffusion of gases.Doucet, L.S., Li, Z.-X., Ernst, R.E., Kirscher, U., El Dien, H.G., Mitchell, R.N., 2019. Coupled supercontinent–mantle plume events evidenced by oceanic plume record. Geology 48, 159-163. most dominant features in the present-day lower mantle are the two antipodal African and Pacific large low-shear-velocity provinces (LLSVPs). How and when these two structures formed, and whether they are fixed and long lived through Earth history or dynamic and linked to the supercontinent cycles, remain first-order geodynamic questions. Hotspots and large igneous provinces (LIPs) are mostly generated above LLSVPs, and it is widely accepted that the African LLSVP existed by at least ca. 200 Ma beneath the supercontinent Pangea. Whereas the continental LIP record has been used to decipher the spatial and temporal variations of plume activity under the continents, plume records of the oceanic realm before ca. 170 Ma are mostly missing due to oceanic subduction. Here, we present the first compilation of an Oceanic Large Igneous Provinces database (O-LIPdb), which represents the preserved oceanic LIP and oceanic island basalt occurrences preserved in ophiolites. Using this database, we are able to reconstruct and compare the record of mantle plume activity in both the continental and oceanic realms for the past 2 b.y., spanning three supercontinent cycles. Time-series analysis reveals hints of similar cyclicity of the plume activity in the continent and oceanic realms, both exhibiting a periodicity of ～500 m.y. that is comparable to the supercontinent cycle, albeit with a slight phase delay. Our results argue for dynamic LLSVPs where the supercontinent cycle and global subduction geometry control the formation and locations of the plumes.Drake, P., 2020. Comment to “More than ten years of Lusi: A review of facts, coincidences, and past and future studies” by Miller and Mazzini (2018): Taking the trigger debate above ground. Marine and Petroleum Geology 113, 104079. erupting in 2006, the “Lapindo” mudflow (or “Lusi,” as it is known by scientists) has released a constant flow of mud that has devastated communities and environments in East Java's Sidoarjo regency. The mudflow also has spawned countless formal and informal scientific reports that dispute what initiated the eruption: drilling for gas or a distant earthquake. A 2018 special issue in Marine and Petroleum Geology by the “Lusi Lab” is devoted entirely to the mudflow, which includes an article by Miller and Mazzini (2018) that presents one perspective of the current status of the trigger debate. This discussion article draws attention to a series of inaccuracies and misrepresentations within Miller and Mazzini’s (2018) article. These concerns include (1) the promotion of erroneous drilling and geological data, (2) the inaccurate and unprofessional characterization of scientists who posit opposing interpretations of drilling and geological data, (3) the use of deceptive rhetoric, (4) the dissemination of misleading and unsubstantiated claims about unnamed stakeholders, and (5) the lack of knowledge of – and sensitivity toward – social contexts. After providing an overview of these issues, this article focuses on items (3), (4) and (5), which tend to be overlooked in ongoing geological discussions on the disaster, but have a significant impact on the production, circulation, and reception of geoscience in both professional and non-professional arenas. This commentary on Miller and Mazzini (2018) does not challenge the credibility or integrity of the authors or any scientist associated with the Lusi Lab, but rather argues for a version of geoscience that stays above ground by being conscientious to the social dynamics that impact, and are impacted by, scientific inquiry. Without the appropriate care and scholarly caution, even the most neutral scientist's work can be perceived as compromised to both scholarly and non-scholarly audiences.Du, F., Nojabaei, B., 2020. A black-oil approach to model produced gas injection in both conventional and tight oil-rich reservoirs to enhance oil recovery. Fuel 263, 116680. robust compositionally extended black-oil simulation approach is developed, which is capable of including the effect of large gas-oil capillary pressure for first contact miscible (FCM), and immiscible gas injection. The simulation methodology is applied to gas flooding in both high and very low permeability reservoirs. For a high permeability conventional reservoir, simulations use a five-spot pattern with different reservoir pressures to mimic both FCM and immiscible displacements. The results show that the simple modified black-oil approach can model well both immiscible and miscible floods, as long as the minimum miscibility pressure (MMP) is matched. For a tight oil-rich reservoir, primary depletion and huff-n-puff gas injection are simulated including the effect of large gas-oil capillary pressure in flow and in flash calculation on recovery. Finally, a dynamic gas-oil relative permeability correlation that accounts for the compositional changes owing to the produced gas injection is introduced and applied to correct for changes in interfacial tension (IFT), and its effect on oil recovery is examined. The results show that the new black-oil approach can model these processes well and could be implemented when fully compositional simulations are computationally too time consuming. For the first time, a black-oil type reservoir simulation method is used to simulate near-miscible and immiscible produced gas injection enhanced oil recovery. It provides a fast and robust alternative for large-scale reservoir simulation with the purpose of flaring/venting reduction through reinjecting the produced gas into the reservoir for EOR.Du, X., Lu, Y., Duan, D., Liu, Z., Zhao, K., Jia, J., Fu, H., 2020. Was volcanic activity during the Ordovician-Silurian transition in South China part of a global phenomenon? Constraints from zircon U–Pb dating of volcanic ash beds in black shales. Marine and Petroleum Geology 114, 104209. volcanic activity during the Ordovician-Silurian transition (OST) in South China (SC) contributed to global volcanic activity has always been a controversial subject. Volcanic ash is the most direct evidence for volcanic activity and represents a good marker to compare SC with the global stratigraphic correlation. Here, we analyze the distribution of volcanic ash beds in three outcrops in SC and precisely determine the ages of volcanic ash zircons using the LA-ICP-MS and SHRIMPII methods.A comparison of the volcanic ash beds in three different outcrops of SC during the OST; indicates that relatively large-scale volcanic activity occurred during this period. The newly obtained zircon U–Pb ages show that the starting time of the Ordovician Wufeng Fm. was approximately 449.2 Ma (or 449.3 Ma), the starting time of the Ordovician Guanyingqiao bed (the ending time of the Wufeng Fm.) was approximately 445.6 Ma, and the starting time of the Longmaxi Fm. was approximately 444.2 Ma. In addition, the durations of the Wufeng Fm. and Guanyingqiao bed were 3.6 Ma and 1.4 Ma, respectively, and the duration of the Hirnantian stage in SC was 1.4 Ma. Most of the ages obtained in this study were basically consistent with that of the International Commission on Stratigraphy (GST 2018). These results provide insights into the volcanic activity during the OST in SC as well as age data for a global stratigraphic framework.Duan, S., Gu, M., Tao, M., Xian, X., 2020. Adsorption of methane on shale: Statistical physics model and site energy distribution studies. Energy & Fuels 34, 304-318. behaviors of methane on four Sichuan Basin shales at different temperatures (318, 338, and 358 K) were experimentally investigated. The adsorption equilibrium data were best fitted by using the modified Hill-monolayer model, in which statistical physics theory was used. Four physicochemical parameters of the number of CH4 molecules per site (n), the density of receptors (Nm), total adsorbed quantity (Qa), and energetic parameter (ΔE) were estimated. The thermodynamic potential functions, including entropy (Sa), internal energy of adsorption (Eint), and Gibbs free energy (Ga), were derived. The results showed multianchorage manner occurs during the adsorption process of CH4 on shale, and the interactions between CH4 molecule and shales are Van der waals forces or hydrophobic bond forces. The adsorption of CH4 on shale is spontaneous and globally exothermic. Besides, the analysis of site energy distribution theory based on statistical physical model showed methane molecules first occupied the high-energy adsorption sites and then diffused and adsorbed on the low-energy sites on shale, and the higher temperature resulted in the higher heterogeneity.Dudek, M., Vik, E.A., Aanesen, S.V., ?ye, G., 2020. Colloid chemistry and experimental techniques for understanding fundamental behaviour of produced water in oil and gas production. Advances in Colloid and Interface Science 276, 102105. to increasing volumes of produced water and environmental concerns related to its discharge, water treatment has become a major challenge during the production of crude oil and natural gas. With continuously stricter regulations for discharging produced water to sea, the operators are obliged to look for ways to improve the treatment processes or re-use the water in a beneficial way, for example as a pressure support during oil recovery (produced water re-injection). To improve the knowledge of the underlying phenomena governing separation processes, detailed information of the composition and interfacial properties of produced water is undoubtedly useful and could provide valuable input for better understanding and improving separation models. This review article summarizes knowledge gained about produced water composition and the most common treatment technologies, which are later used to describe the fundamental phenomena occurring during separation. These colloidal interactions, such as coalescence of oil droplets, bubble-droplet attachment or partitioning of components between oil and water, are of crucial importance for the performance of various technologies and are sometimes overlooked in physical considerations of produced water treatment. The last part of the review deals with the experimental methodologies that are available to study these phenomena, provide data for models and support development of more efficient separation processes.Editorial, 2020. The life of archaea. Nature 577, 249. of Asgard archaea brings us closer to understanding how complex life evolved. Hilaire Belloc’s ‘The Microbe’ opens with the words:The microbe is so very small / You cannot make him out at all.The poem lists the wonders of microorganisms, and they continue to reveal their secrets to researchers more than a century after his book The Bad Child’s Book of Beasts (1896) excited and delighted children.In 2015, researchers published the metagenome of a member of the Asgard group of archaea called Lokiarchaeota (A. Spang et al. Nature 521, 173–179; 2015). These are descended from an ancient lineage of archaea, simple cells lacking a nucleus and distinct from bacteria. This discovery was exciting because the genes were found to have similarities with those of eukaryotes — the group of organisms whose cells have nuclei and other structures, and which include plants, fungi, humans and other animals. That suggested a stronger connection between archaea and eukaryotes than had previously been thought.Now, after a heroic effort that took 12 years, researchers led by Hiroyuki Imachi, a microbiologist at the Japan Agency for Marine-Earth Science and Technology, Yokosuka, have successfully grown a new Asgard lineage (H. Imachi et al. Nature ; 2020). This achievement puts to rest concerns that the genes sequenced in 2015 were the result of contamination, or the initial sample being a mix of cells.Imachi and his colleagues grew cells from sediment that had been collected below the sea bed. But why did the cells take so long to grow? The problem in culturing cells from sediment is that most microbes aren’t as obliging as familiar lab workhorses such as Escherichia coli. The researchers took up the challenge and with much patience, trial and error, they found that the cells grew best on a diet of peptides, amino acids and even baby-milk powder.The resulting cells are tiny spheres 300–750 nanometres in diameter, but they often extrude longer, branched filaments that reach out to meet neighbouring bacteria. The researchers think that such a partnership, both biochemical and physical, could tell us more about the processes that led to the eukaryote cell being formed — a question more researchers must surely try to tackle.Despite the promise of what is to come, a degree of caution is needed. Eukaryotes evolved more than two billion years ago, possibly coincident with an episode of global climatic change called the Great Oxidation Event. Nonetheless, the achievement brings us closer to meeting living relatives of our ancestors. We await the next chapter with anticipation.Eguchi, J., Seales, J., Dasgupta, R., 2020. Great Oxidation and Lomagundi events linked by deep cycling and enhanced degassing of carbon. Nature Geoscience 13, 71-76. approximately the first 2?billion years of the Earth’s history, atmospheric oxygen levels were extremely low. It was not until at least half a billion years after the evolution of oxygenic photosynthesis, perhaps as early as 3?billion years ago, that oxygen rose to appreciable levels during the Great Oxidation Event. Shortly after, marine carbonates underwent a large positive spike in carbon isotope ratios known as the Lomagundi event. The mechanisms responsible for the Great Oxidation and Lomagundi events remain debated. Using a carbon–oxygen box model that tracks the Earth’s surface and interior carbon fluxes and reservoirs, while also tracking carbon isotopes and atmospheric oxygen levels, we demonstrate that about 2.5?billion years ago a tectonic transition that resulted in increased volcanic CO2 emissions could have led to increased deposition of both carbonates and organic carbon (organic?C)?via enhanced weathering and nutrient delivery to oceans. Increased burial of carbonates and organic?C would have allowed the accumulation of atmospheric oxygen while also increasing the delivery of carbon to subduction zones. Coupled with preferential release of carbonates at arc volcanoes and deep recycling of organic?C to ocean island volcanoes, we find that such a tectonic transition can simultaneously explain the Great Oxidation and Lomagundi events without any change in the fraction of carbon buried as organic?C relative to carbonate, which is often invoked to explain carbon isotope excursions.El Diasty, W.S., Peters, K.E., Moldowan, J.M., Essa, G.I., Hammad, M.M., 2020. Organic geochemistry of condensates and natural gases in the northwest Nile Delta offshore Egypt. Journal of Petroleum Science and Engineering 187, 106819. recent gas and condensate discoveries have been achieved in the deep ultramarine Nile Delta Basin of northern Egypt, the genetic origin and formation mechanisms of these hydrocarbons remain unclear. Twenty condensate and 34 natural gas samples from Miocene–Pliocene sandstone reservoirs in the northwest Nile Delta offshore Egypt were analyzed to infer their origin, degree of thermal maturity, and extent of alteration.Based on source-related biomarkers, the condensate samples were interpreted to have originated from clay-rich non-marine source rocks, based on high Pr/Ph, high Ts/Tm, low or absent C30 n-propylcholestanes and high hopane/sterane ratios. The environment of deposition of the source rock is expected to be proximal and likely received high influx of terrigenous-dominated organic matter. Chemometrics of 12 source-related biomarker and isotopic ratios identify six genetic families. Geochemical characterization of the families shows that they are broadly similar but differ in terms of source-rock depositional paleoenvironment, organic matter precursors, thermal maturation and microbial degradation. Age and maturity biomarker fingerprints show that these hydrocarbons were generated from at least two active pods of Upper Cretaceous and Oligocene or younger source rocks, as confirmed by high oleananes, bicadinanes, and high C26 24-norcholestane indices.Gas chemical and isotopic compositions of propane, ethane, and methane reveal a mixed microbial and thermogenic origin, where the relative proportion of biogenic component reaches up to ~70%. The thermogenic gas was generated from mixed Type-II/III or Type-II kerogen with a wide range of maturity between 1.0% and 1.5% Ro from primary kerogen cracking to the late stage of gas cracking. Heavier C2+ hydrocarbon isotope signatures and bulk compositions indicate that the shallower gas accumulations are severely biodegraded, unlike that in the deep hydrocarbon reservoirs. The co-occurrence of unaltered gas with biodegraded condensates may indicate different microbial communities involved in these processes, or more likely, the gas arrived in the reservoir as a second charge after biodegradation of the original condensate.Elkahky, S., Lagat, C., Sarmadivaleh, M., Barifcani, A., 2019. A comparative study of density estimation of asphaltene structures using group contribution methods and molecular dynamic simulations for an Australian oil field. Journal of Petroleum Exploration and Production Technology 9, 2699-2708. of the major challenges faced by oil extraction industry is the unstable behavior of asphaltene formation, yet not fully understood. The prediction of asphaltene formation depends on the small changes in chemical characteristics and composition of the crude oil. Consequently, the study of molecular structure and molecular properties such as density is of a great practical interest. Other properties become very complex to assess when the asphaltene fraction contains 105 different molecules. Average molecular parameters are used to obtain information about asphaltenes. The density of the asphaltenes can easily be calculated and, thus, can be used to evaluate predictive capacities of the average structure. This present work of molecular dynamic simulations was carried out to evaluate the asphaltene densities of an Australian oil field. Simulations of molecular dynamics are used to assess the average structure densities representing different asphaltenes in a specific oil field. These simulations assist in predicting the formation of asphaltene structural model. Comparatively, the experimental densities are higher than the calculated ones. However, the calculated values demonstrate the appropriate trend. The chemical structure shows essential accuracy, as evidenced by average structures, which can be used to estimate the densities qualitatively. Hence, systematic study was carried out on the basis of the effects of various structures on the calculated densities of asphaltene. The main characteristics of the molecules which yielded highest densities are those found with low hydrogen–carbon ratio and big condensed aromatic rings. Moreover, better and improved density values were produced by a recently developed group contribution method than simulations of molecular dynamics, which is still being lower than that of experimental values.Elkasabi, Y., Wyatt, V., Jones, K., Strahan, G.D., Mullen, C.A., Boateng, A.A., 2020. Hydrocarbons extracted from advanced pyrolysis bio-oils: Characterization and refining. Energy & Fuels 34, 483-490. fast pyrolysis (CFP) and tail-gas reactive pyrolysis (TGRP) of biomass produce partially deoxygenated bio-oils (10–20 wt % O) which allow for subsequent separation into phenolic and hydrocarbon fractions. The hydrocarbon fraction, while low in oxygen (<2 wt %), still requires further upgrading to become a finished fuel blendstock. In particular, the hydrogen deficiency, molecular weight distribution, and benzene content require further treatment. Specific biomass feedstocks like guayule carry over significant amounts of sulfur (～500 ppm) even after catalytic hydrodeoxygenation. Our strategy was to fractionate the hydrocarbon fraction using distillation and then upgrade each fraction according to its needed product changes, including desulfurization. For each hydrocarbon fraction, sulfur levels ranged from 80–700 ppm, increasing with respect to decreasing volatility. Light fractions contained primarily one-ring aromatics, with heavy fractions increasing to two-ring aromatics. The lightest fraction (<143 °C) contained 6 wt % benzene, and fraction 2 (143–163 °C) required minimal treatment, as it consisted of nearly 100% BTEX (benzene, toluene, ethylbenzene, and xylenes). Sponge nickel catalysis in one step (<80 °C) eliminated sulfur in all fractions down to below 10 ppm with the exception of the hydrocarbon distillation residue, indicating that the sulfur remained labile even after biomass pyrolysis. Catalysis in two stages (80 °C, then 200 °C) eliminated benzene and produced naphtha and/or tetralin, which can be used to improve combustibility of jet fuels.Ellwood, B.B., Nestell, G.P., Lan, L.T.P., Nestell, M.K., Tomkin, J.H., Ratcliffe, K.T., Wang, W.-H., Rowe, H., Nguyen, T.D., Nguyen, C.T., Dang, T.H., 2020. The Permian–Triassic boundary Lung Cam expanded section, Vietnam, as a high-resolution proxy for the GSSP at Meishan, China. Geological Magazine 157, 65-79. Lung Cam expanded stratigraphic succession in Vietnam is correlated herein to the Meishan D section in China, the GSSP for the Permian–Triassic boundary. The first appearance datum of the conodont Hindeodus parvus at Meishan defines the Permian–Triassic boundary, and using published graphic correlation, the Permian–Triassic boundary level has been projected into the Lung Cam section. Using time-series analysis of magnetic susceptibility (χ) data, it is determined that H. parvus arrived at Lung Cam ～18 kyr before the Permian–Triassic boundary. Data indicate that the Lung Cam section is expanded by ～90 % relative to the GSSP section at Meishan. Given the expanded Lung Cam section, it is possible to resolve the timing of significant events during the Permian–Triassic transition with high precision. These events include major stepped extinctions, beginning at ～135 kyr and ending at ～110 kyr below the Permian–Triassic boundary, with a duration of ～25 kyr, followed by deposition of Lung Cam ash Bed + 13, which is equivalent to Siberian Traps volcanism is graphically correlated to a precession Time-series model, placing onset of this major volcanic event at ~242 kyr before the PTB. The Meishan Beds 25 and 26, at ～100 kyr before the Permian–Triassic boundary. In addition, the elemental geochemical, carbon and oxygen isotope stratigraphy, and magnetostratigraphy susceptibility datasets from Lung Cam allow good correlation to other Permian–Triassic boundary succession. These datasets are helpful when the conodont biostratigraphy is poorly known in sections with problems such as lithofacies variability, or is undefined, owing possibly to lithofacies exclusions, anoxia or for other reasons. The Lung Pu Permian–Triassic boundary section, ～45 km from Lung Cam, is used to test these problems.Elmaadawy, K.G., 2020. Thermal maturity modelling for the pre-Miocene source rocks in Ras Garra area, Suez rift Basin, Egypt. Journal of African Earth Sciences 163, 103746. main potential source rocks in the Ras Garra area of the Suez rift Basin are thought to be the pre-Miocene formations, Duwi, Esna, and Thebes, from the oldest to youngest. The total organic carbon content (TOC) ranges from 6.0 to 7.0?wt %, suggesting very good hydrocarbon generative potential. The hydrogen index (HI) ranges from 600 to 700 mg HC/g TOC and the kerogen is of type I/II. Burial and thermal maturity modelling indicates that the pre-Miocene source rocks started the oil generation as early mature stage in Langhian (14.3 Ma), and mid-mature stage in Pleistocene (2.4 Ma). The early mature stage is characterized by the depth to maturity of 1400 m, burial maximum temperature up to 87?°C and vitrinite reflectance (VR) up to 0.7% Ro. The mid-mature stage is characterized by the depth to maturity of 3007 m, burial maximum temperature up to 120?°C and vitrinite reflectance up to 0.75% Ro. The hydrocarbon generation and expulsion history is divided into two phases and Duwi source rock passed the second phase of hydrocarbon generation, and expulsion with transformation ratio (TR) of 29%. From 0.8 Ma until the present, the hydrocarbon generation and expulsion rates have been increased and the generated and expelled hydrocarbons are mainly oil with minor gases. The results show that the most important factor affecting the maturity of the source rocks and hydrocarbon generation and expulsion rates is the durations of early and mid-mature stages.Elsayed, M., Mahmoud, M., El-Husseiny, A., Kamal, M.S., Al-Garadi, K., 2019. A new method to evaluate reaction kinetics of acids with carbonate rocks using NMR diffusion measurements. Energy & Fuels 34, 787-797. this work, a new method to evaluate the reaction kinetics of different stimulation fluids with carbonate rocks was introduced. NMR diffusion measurements were used to determine the acid diffusion coefficient and the acid tortuous path inside carbonate rocks. Reaction kinetics can also be evaluated using rotating disk apparatus (RDA) in which a disc is rotated in the bulk fluid at different rotational speeds. RDA does not represent the actual, restricted acid diffusion that takes place in the porous media because only the surface of the rock is exposed to the reaction and the acid is not confined in the porous media. NMR diffusion measurements can accurately describe and determine the acid restricted diffusion in porous media. The diffusion coefficient of the acid is a crucial term in describing the reaction kinetics of acids with carbonate rocks. It is also used to predict the optimum injection rate required during the acidizing treatment and the soaking time for different fluids required to remove scales and deposits in the wellbore. The restricted diffusion was determined for different fluids such as GLDA chelating agent, HEDTA chelating agent, and EDTA chelating agent. Core flooding experiments for each fluid were conducted to determine the optimum injection rate. NMR restricted diffusion measurements then were conducted to determine the restricted diffusion and in turn to determine the optimum injection rate. The optimum injection rate estimated from the NMR was compared to that from the core flooding experiments. The results were a good match showing that NMR is a suitable, reliable, and robust method to evaluate reaction kinetics of different fluids with carbonate rocks.Enayat, S., Tran, M.K., Salpekar, D., Kabbani, M.A., Babu, G., Ajayan, P.M., Vargas, F.M., 2020. From crude oil production nuisance to promising energy storage material: Development of high-performance asphaltene-derived supercapacitors. Fuel 263, 116641. require the use of electrode materials exhibiting high surface area, thermal and environmental stability, low cost and good conductivity. Asphaltene, an undesired and problematic fraction of crude oil production, is one such cost-effective material that when activated, can provide desirable properties to be used in energy storage devices. In this work, a new and simple method to chemically activate asphaltene was designed using commercially available melamine sponges as a template to form an interconnected porous carbon network. The asphaltene derived carbon showed a surface area as high as 3868?m2g?1, and electrochemical capacitance in a standard aqueous electrolyte as high as 197.3F g?1 has been realized. After testing the asphaltene electrode-based supercapacitor device for 10,000 cycles, 89.9% of its capacitance was retained, indicating good stability for an energy storage device. Additionally, the use of asphaltene electrodes with “water-in-salt” electrolyte showed potential for higher voltage supercapacitors operating up to 2.5?V, with an energy density of 31Wh kg?1. These results suggest that what is currently considered an undesirable fraction of the crude oil, which has a tendency to deposit in wellbores, pipelines, and downstream facilities can be repurposed into a desirable material with remarkable properties for energy storage.Epuh, E.E., Joshua, E.O., 2020. Modeling of porosity and permeability for hydrocarbon exploration: A case study of Gongola arm of the Upper Benue Trough. Journal of African Earth Sciences 162, 103646. water saturation is one of the fundamental parameters in characterizing hydrocarbon formations, playing key role in volumetric and recovery calculations and permeability definition within a reservoir. The determination of the reservoir permeability using the irreducible water saturation in a shaly sand transition zone has been problematic due to the presence of the bound water saturation. In this research, a model was developed based on the Coates and Dagan permeability model formulation using the dual water model parameters. In this model formulation using the three models, a sensitivity coefficient for conditioning the permeability field at the transition zone was introduced. The sensitivity factor is a quotient function of bound water saturation and the total water saturation. The localized nature of the well data in the determination of the depositional architecture (porosity and permeability) were extrapolated away from or interpolated between acquisition locations using the areal coverage provided by seismic data. The analysis of the well information from the Kolmani River showed that the hydrocarbon lies at depth between 2071m and 2194m (Cenomenian-Turonian Yolde formation). The acoustic map within the reservoir shows the occurrence of dense uniform marine shales and sandstones. It also shows the depositional process has been uniform and sequential. High density clastic materials were also discovered within the reservoir. The permeability results obtained by equating the bound water and total water saturations to the irreducible water saturation gave the 26mD and 16mD as the upper (clean sand) and lower (pure shale) limits of the effective permeability values for the reservoir. The result obtained using the new model showed that the effective permeability is 21mD within the transition zone. Other petrophysical results showed that the reservoir has an effective porosity of 20% and effective water saturation of 12%. Based on these reservoir results, it is understood that the well is highly compact and will not flow during production.Erickson, T.M., Kirkland, C.L., Timms, N.E., Cavosie, A.J., Davison, T.M., 2020. Precise radiometric age establishes Yarrabubba, Western Australia, as Earth’s oldest recognised meteorite impact structure. Nature Communications 11, 300. ~70 km-diameter Yarrabubba impact structure in Western Australia is regarded as among Earth’s oldest, but has hitherto lacked precise age constraints. Here we present U–Pb ages for impact-driven shock-recrystallised accessory minerals. Shock-recrystallised monazite yields a precise impact age of 2229?±?5?Ma, coeval with shock-reset zircon. This result establishes Yarrabubba as the oldest recognised meteorite impact structure on Earth, extending the terrestrial cratering record back?>200 million years. The age of Yarrabubba coincides, within uncertainty, with temporal constraint for the youngest Palaeoproterozoic glacial deposits, the Rietfontein diamictite in South Africa. Numerical impact simulations indicate that a 70 km-diameter crater into a continental glacier could release between 8.7?×?1013 to 5.0?×?1015 kg of H2O vapour instantaneously into the atmosphere. These results provide new estimates of impact-produced H2O vapour abundances for models investigating termination of the Paleoproterozoic glaciations, and highlight the possible role of impact cratering in modifying Earth’s climate.Ernst, R.E., Rodygin, S.A., Grinev, O.M., 2020. Age correlation of Large Igneous Provinces with Devonian biotic crises. Global and Planetary Change 185, 103097. Igneous Provinces (LIPs) are emerging as a significant driver of short duration climatic change including mass extinctions. Here we compare the record of LIPs against the timing of Devonian biotic crises that are well recorded in the numerous anoxia events throughout this period. The largest LIPs are two-pulse events at ca. 370 and ca. 360 Ma that are present in both Siberia (Yakutsk-Vilyui LIP) and Baltica (Kola-Dnieper LIP) and correlate with the Kellwasser anoxia events (late Frasnian) and Annulata or Dasberg and Hangenberg anoxia events in the late/latest Famennian. The regionally significant Altai Sayan LIP is only approximately dated at c.400 Ma and within uncertainties could be linked to either (or both?) the c. 405 Ma Chebbi or Atopus anoxia events near the basal Emsian (associated with graptolite extinction) or the c. 385–390 Ma group of anoxia events in the Eifelian or Givetian.Additional magmatic events that are less precisely dated are: 1) the c. 400–345 Ma Kedon magmatism of the Omolon craton, possibly linked with the Yakutsk-Vilyui event, 2) 380–330 Ma Maritimes (Magdalen) basin event of the Appalachian region of eastern Canada and adjacent US, 3) middle-late Devonian Selwyn basin alkaline magmatism of northwestern Canada, and 4) the Ordovician - late Silurian- possibly Devonian Soltan Maidan event Iran. However, more precise dating is required for each of these magmatic events before they can be properly compared with the Devonian biotic crisis record.Escher, B.I., Abagyan, R., Embry, M., Klüver, N., Redman, A.D., Zarfl, C., Parkerton, T.F., 2020. Recommendations for improving methods and models for aquatic hazard assessment of ionizable organic chemicals. Environmental Toxicology and Chemistry 39, 269-286. organic chemicals (IOCs) such as organic acids and bases are an important substance class requiring aquatic hazard evaluation. Although the aquatic toxicity of IOCs is highly dependent on the water pH, many toxicity studies in the literature cannot be interpreted because pH was not reported or not kept constant during the experiment, calling for an adaptation and improvement of testing guidelines. The modulating influence of pH on toxicity is mainly caused by pH‐dependent uptake and bioaccumulation of IOCs, which can be described by ion‐trapping and toxicokinetic models. The internal effect concentrations of IOCs were found to be independent of the external pH because of organisms’ and cells’ ability to maintain a stable internal pH milieu. If the external pH is close to the internal pH, existing quantitative structure–activity relationships (QSARs) for neutral organics can be adapted by substituting the octanol–water partition coefficient by the ionization‐corrected liposome–water distribution ratio as the hydrophobicity descriptor, demonstrated by modification of the target lipid model. Charged, zwitterionic and neutral species of an IOC can all contribute to observed toxicity, either through concentration‐additive mixture effects or by interaction of different species, as is the case for uncoupling of mitochondrial respiration. For specifically acting IOCs, we recommend a 2‐step screening procedure with ion‐trapping/QSAR models used to predict the baseline toxicity, followed by adjustment using the toxic ratio derived from in vitro systems. Receptor‐ or plasma‐binding models also show promise for elucidating IOC toxicity. The present review is intended to help demystify the ecotoxicity of IOCs and provide recommendations for their hazard and risk assessment. Escher, B.I., Stapleton, H.M., Schymanski, E.L., 2020. Tracking complex mixtures of chemicals in our changing environment. Science 367, 388-392. have improved our quality of life, but the resulting environmental pollution has the potential to cause detrimental effects on humans and the environment. People and biota are chronically exposed to thousands of chemicals from various environmental sources through multiple pathways. Environmental chemists and toxicologists have moved beyond detecting and quantifying single chemicals to characterizing complex mixtures of chemicals in indoor and outdoor environments and biological matrices. We highlight analytical and bioanalytical approaches to isolating, characterizing, and tracking groups of chemicals of concern in complex matrices. Techniques that combine chemical analysis and bioassays have the potential to facilitate the identification of mixtures of chemicals that pose a combined risk.Fakher, S., Imqam, A., 2020. Application of carbon dioxide injection in shale oil reservoirs for increasing oil recovery and carbon dioxide storage. Fuel 265, 116944. dioxide (CO2) injection is an enhanced oil recovery method that has the potential to increase oil recovery from unconventional shale reservoirs while also storing a portion of the injected CO2 into the reservoir thus reducing the CO2 environmental impact. This research studies the ability of cyclic CO2 injection to increase oil recovery from shale cores and the impact of different factors on the oil recovery potential. The research then studies the ability to store the injected CO2 in the shale through adsorption and the storage capacity at different reservoir thermodynamic conditions. Oil recovery was impacted significantly by the CO2 injection pressure. The CO2 phase was also found to be a factor related to the CO2 injection pressure and also had a strong impact on oil recovery. Increasing the soaking time of the CO2 increased the oil recovery due to the increase in the interaction time between the CO2 and the crude oil. The storage potential of the CO2 in the shale was influenced significantly by the pressure and temperature. Increasing the CO2 injection pressure increased the CO2 adsorption, while increasing the temperature decreased the adsorption capacity. Based on the experiments conducted, it was found that cyclic CO2 injection could be a means of both increasing oil recovery from shale reservoirs and also for CO2 storage operations to reduce CO2 environmental impact.Fan, J.-x., Shen, S.-z., Erwin, D.H., Sadler, P.M., MacLeod, N., Cheng, Q.-m., Hou, X.-d., Yang, J., Wang, X.-d., Wang, Y., Zhang, H., Chen, X., Li, G.-x., Zhang, Y.-c., Shi, Y.-k., Yuan, D.-x., Chen, Q., Zhang, L.-n., Li, C., Zhao, Y.-y., 2020. A high-resolution summary of Cambrian to Early Triassic marine invertebrate biodiversity. Science 367, 272-277.: One great challenge in understanding the history of life is resolving the influence of environmental change on biodiversity. Simulated annealing and genetic algorithms were used to synthesize data from 11,000 marine fossil species, collected from more than 3000 stratigraphic sections, to generate a new Cambrian to Triassic biodiversity curve with an imputed temporal resolution of 26 ± 14.9 thousand years. This increased resolution clarifies the timing of known diversification and extinction events. Comparative analysis suggests that partial pressure of carbon dioxide (Pco2) is the only environmental factor that seems to display a secular pattern similar to that of biodiversity, but this similarity was not confirmed when autocorrelation within that time series was analyzed by detrending. These results demonstrate that fossil data can provide the temporal and taxonomic resolutions necessary to test (paleo)biological hypotheses at a level of detail approaching those of long-term ecological analyses.Editor's Summary: A finer record of biodiversity. We have pressing, human-generated reasons to explore the influence of environmental change on biodiversity. Looking into the past can not only inform our understanding of this relationship but also help us to understand current change. Paleontological records depend on fossil availability and predictive modeling, however, and thus tend to give us a picture with large temporal jumps, millions of years wide. Such a scale makes it difficult to truly understand the action of environmental forces on ecological processes. Enabled by a supercomputer, Fan et al. used machine learning to analyze a large marine Paleozoic dataset, creating a record with time intervals of only ～26,000 years (see the Perspective by Wagner). This fine-scale resolution revealed new events and important details of previously described patterns.Fan, M., Andrade, G.F.S., Brolo, A.G., 2020. A review on recent advances in the applications of surface-enhanced Raman scattering in analytical chemistry. Analytica Chimica Acta 1097, 1-29. review is focused on recent developments of surface-enhanced Raman scattering (SERS) applications in Analytical Chemistry. The work covers advances in the fabrication methods of SERS substrates, including nanoparticles immobilization techniques and advanced nanopatterning with metallic features. Recent insights in quantitative and sampling methods for SERS implementation and the development of new SERS-based approaches for both qualitative and quantitative analysis are discussed. The advent of methods for pre-concentration and new approaches for single-molecule SERS quantification, such as the digital SERS procedure, has provided additional improvements in the analytical figures-of-merit for analysis and assays based on SERS. The use of metal nanostructures as SERS detection elements integrated in devices, such as microfluidic systems and optical fibers, provided new tools for SERS applications that expand beyond the laboratory environment, bringing new opportunities for real-time field tests and process monitoring based on SERS. Finally, selected examples of SERS applications in analytical and bioanalytical chemistry are discussed.The breadth of this work reflects the vast diversity of subjects and approaches that are inherent to the SERS field. The state of the field indicates the potential for a variety of new SERS-based methods and technologies that can be routinely applied in analytical laboratories.Fang, L., Lee, S., Lee, S.-A., Hahm, D., Kim, G., Druffel, E.R.M., Hwang, J., 2020. Removal of refractory dissolved organic carbon in the Amundsen Sea, Antarctica. Scientific Reports 10, 1213. removal mechanism of refractory deep-ocean dissolved organic carbon (deep-DOC) is poorly understood. The Amundsen Sea Polynya (ASP) serves as a natural test basin for assessing the fate of deep-DOC when it is supplied with a large amount of fresh-DOC and exposed to strong solar radiation during the polynya opening in austral summer. We measured the radiocarbon content of DOC in the water column on the western Amundsen shelf. The radiocarbon content of DOC in the surface water of the ASP reflected higher primary production than in the region covered by sea ice. The radiocarbon measurements of DOC, taken two years apart in the ASP, were different, suggesting rapid cycling of DOC. The increase in DOC concentration was less than expected from the observed increase in radiocarbon content from those at the greatest depths. Based on a radiocarbon mass balance, we show that deep-DOC is consumed along with fresh-DOC in the ASP. Our observations imply that water circulation through the surface layer, where fresh-DOC is produced, may play an important role in global DOC cycling.Farnsworth, K.K., Chevrier, V.F., Steckloff, J.K., Laxton, D., Singh, S., Soto, A., Soderblom, J.M., 2019. Nitrogen exsolution and bubble formation in Titan's lakes. Geophysical Research Letters 46, 13658-13667.: Titan's surface liquids are composed primarily of methane, ethane, and dissolved atmospheric nitrogen. The nitrogen content depends on the alkane composition and temperature, and exsolves as bubbles when these parameters are sufficiently perturbed. Herein, we present an experimental study of nitrogen bubbles in methane–ethane liquids, and propose that both methane and ethane are required for bubbles to form under Titan conditions. Bubbles occur when methane composes 40–95 mol% of the alkanes within the liquid. We identify two mechanisms that produce bubbles: ethane mediated titration and temperature‐induced stratification. Both of these mechanisms produce a metastable nitrogen supersaturation within the liquid; equilibration triggers rapid nitrogen exsolution in the form of bubbles. Such equilibration could cause bubble events in Titan's lakes, possibly explaining the transient “Magic Island” features seen by Cassini RADAR (bubbles within the liquid column), and the presence of deltas in Ontario Lacus.Plain Language Summary: Saturn's largest moon, Titan, has stable lakes on its surface composed of liquid methane, ethane, and dissolved atmospheric nitrogen. While nitrogen can dissolve into the liquid (dissolution), it can also be forced out of the liquid (exsolution). Nitrogen bubbles in Titan's lakes have been hypothesized, but not experimentally measured under Titan surface conditions. Here we create bubbles in a laboratory under Titan conditions using two methods: ethane slowly added to methane (titration) and temperature‐induced methane‐ethane liquid layering (cooling then warming). Both mechanisms create a metastable supersaturation of nitrogen. Once the metastable limit is reached, bubble nucleation occurs, triggering rapid bubble formation. Transient bright structures observed in Titan's lakes by the Cassini RADAR, known as “Magic Islands,” may in fact be bubbles within the liquid column. Bubbles can also form in rivers as they flow into lakes and seas, potentially influencing geologic structures, such as the delta seen in one of Titan's largest lakes, Ontario Lacus.Fayet, A.L., Hansen, E.S., Biro, D., 2020. Evidence of tool use in a seabird. Proceedings of the National Academy of Sciences 117, 1277-1279. novel cases of tool use in wild animals can inform our understanding of the evolutionary drivers of the behavior’s emergence in the natural world. We describe a previously unknown tool-use behavior for wild birds, so far only documented in the wild in primates and elephants. We observed 2 Atlantic puffins at their breeding colonies, one in Wales and the other in Iceland (the latter captured on camera), spontaneously using a small wooden stick to scratch their bodies. The importance of these observations is 3-fold. First, while to date only a single form of body-care-related tool use has been recorded in wild birds (anting), our finding shows that the wild avian tool-use repertoire is wider than previously thought and extends to contexts other than food extraction. Second, we expand the taxonomic breadth of tool use to include another group of birds, seabirds, and a different suborder (Lari). Third, our independent observations span a distance of more than 1,700 km, suggesting that occasional tool use may be widespread in this group, and that seabirds’ physical cognition may have been underestimated.Ferguson, A., Solo-Gabriele, H., Mena, K., 2020. Assessment for oil spill chemicals: Current knowledge, data gaps, and uncertainties addressing human physical health risk. Marine Pollution Bulletin 150, 110746. models are available to estimate human physical health risks (e.g., probability of outcomes such as lung disease, cancer, skin disease) from exposure to chemicals resulting from oil spills that may occur offshore and later impact coastline spills. An approach is presented to assess physical health risks from oil spills that involves establishing a platform capable of assessing aggregate health risk (via inhalation, ingestion, and dermal exposure routes). Gaps include the need to develop models reflecting oil spill concentration distributions given the influence from environmental, physical, biological and chemical factors. Human activities need to be quantified for different populations including emergency response workers, fishermen, shellfish consumers, and children who play at beaches that may be impacted by oil spills. Work is also needed in developing comprehensive toxicological profiles for the majority of chemicals - including dispersants found in oil spills - and to estimate toxicity from mixtures.Fernandes, C., Khandeparker, R.D.S., Shenoy, B.D., 2020. High abundance of Vibrio in tarball-contaminated seawater from Vagator beach, Goa, India. Marine Pollution Bulletin 150, 110773. are semi-solid remnants of crude oil and they are formed in marine environment after oil-spill incidents. They are composed of diverse hydrocarbons; some of which are recalcitrant in nature. Recent studies based on amplicon sequencing of 16S rRNA gene suggested that tarballs support hundreds of bacterial genera and provided insights into their role as hydrocarbon degraders and potential human pathogens. In this study, bacterial composition of tarball-contaminated seawater from Vagator beach, Goa, India was characterized by amplicon sequencing of V3–V4 regions of 16S rRNA gene. The DNA data revealed an unusual surge of Vibrio in sea-water contaminated with tarballs in May 2018 (16.16% OTUs), compared to tarball-free seawater samples collected in March 2018 (no detectable OTUs) and September 2018 (0.17% OTUs). Further studies are required to investigate if Vibrio species form biofilms on tarballs which may act as good reservoirs for their survival and transmission success.Fernandes, G.L., Shenoy, B.D., Damare, S.R., 2020. Diversity of bacterial community in the oxygen minimum zones of Arabian Sea and Bay of Bengal as deduced by Illumina sequencing. Frontiers in Microbiology 10, 3153. doi: 10.3389/fmicb.2019. 03153. Indian Ocean harbors oxygen minimum zones (OMZs) in the Arabian Sea and Bay of Bengal, with dissolved oxygen < 20 μM, located at the mid-depths of the water column. Till date, high-throughput sequence-data on depth-wise distribution of prokaryotic communities have rarely been reported from these OMZs. The present study aimed to characterize the prokaryotic diversity inhabiting Arabian Sea Time Series (ASTS) and India’s Idea 2 (II2) in the Arabian Sea, and Bay of Bengal Time Series (BoBTS) in the Bay of Bengal OMZs based on amplicon sequencing of 16S rRNA gene regions, along six sampled depths in the water column. High prokaryotic richness was observed in the Arabian Sea and Bay of Bengal samples. Operational taxonomic units (OTUs) in the range of 1249–3298 were identified, wherein, less prokaryotic diversity was observed at surface and within oxygen minimum depths. At phylum level, most OTUs were affiliated to Bacteroidetes, Chloroflexi, Cyanobacteria, Marinimicrobia, Planctomycetes, and Proteobacteria. Prokaryotic community differed between ASTS, II2 and BoBTS locations along varying physicochemical conditions. Predictive functional profiling of the bacterial communities suggested the involvement of abundant microbes in nitrogen and sulfur metabolism pathways. Bacterial isolates belonging to genera from the clades, δ-Proteobacteria and γ-Proteobacteria, described previously for their participation in biogeochemical cycling of N-and-S in the OMZs were reported from deoxygenated waters of both the basins. Bacteria involved in anammox such as Candidatus Scalindua were found to be relatively high at ASTS and II2 locations in the Arabian Sea. Further studies are required to ascertain the role of abundant bacteria along the dynamic oceanographic processes in the OMZs.Fernández-Crespo, T., Snoeck, C., Ordo?o, J., de Winter, N.J., Czermak, A., Mattielli, N., Lee-Thorp, J.A., Schulting, R.J., 2020. Multi-isotope evidence for the emergence of cultural alterity in Late Neolithic Europe. Science Advances 6, eaay2169. coexistence of cultural identities and their interaction is a fundamental topic of social sciences that is not easily addressed in prehistory. Differences in mortuary treatment can help approach this issue. Here, we present a multi-isotope study to track both diet and mobility through the life histories of 32 broadly coeval Late Neolithic individuals interred in caves and in megalithic graves of a restricted region of northern Iberia. The results show significant differences in infant- and child-rearing practices, in subsistence strategies, and in landscape use between burial locations. From this, we posit that the presence of communities with distinct lifestyles and cultural backgrounds is a primary reason for Late Neolithic variability in burial location in Western Europe and provides evidence of an early “them and us” scenario. We argue that this differentiation could have played a role in the building of lasting structures of socioeconomic inequality and, occasionally, violent conflict.Forbes, P., 2020. Atmospheric chemistry analysis: A review. Analytical Chemistry 92, 455-472. monitoring of our atmosphere is a vital component of analytical chemistry, on the basis of the fact that air quality has a direct impact on the environment and human health. Air pollution has been shown to be involved in numerous pathologies, typically cardiovascular and respiratory based, but also links to reproductive function have been made.(1) Many impacts of air pollution are complex and result from the chemical and physical interactions of a number of atmospheric species from a plethora of sources.(2) A recent review, for example, explored the interplay of air pollution, food production, and food security, where food production incurs air pollution which in turn negatively impacts food security.(3) It is clear that it is insufficient to merely determine the levels of air pollutants, such as particulate matter of diameter 2.5 μm or less (PM2.5), to estimate human health impacts,(4) as the chemical composition thereof has a great bearing on toxicity, which varies considerably spatiotemporally. The atmosphere is a shared resource; therefore, the scale of air pollution impacts may range from local to transboundary. Many air pollutants are known to incur deleterious effects at trace concentrations, while potential effects of chronic exposure to low concentrations of some species in the atmosphere have not yet been determined. This necessitates the ongoing development of sensitive and selective analytical methods for an ever increasing range of analytes to drive the science forward and allow for a better understanding of this complex field. Studies to monitor the atmosphere differ substantially in terms of geographical and temporal coverage, which have concomitant differing requirements in terms of sampling and analytical approaches. Additional drivers that inform the choice of the analytical approach include target analytes, legislative requirements, and available resources. In this Review, developments over approximately the last two years (methodologies and applications published since 2017, with a few exceptions that deserve mentioning due to their fundamental relevance) in the field of atmospheric chemistry monitoring are explored (Figure 1), covering sampling and analytical approaches, where the latter focuses on laboratory based analyses, although pertinent applications of sensor and remote sensing technologies are described. The Review focuses on recent developments in the monitoring of gas and particle phase atmospheric species and does not include occupational or indoor air quality monitoring (refer to Farmer(5) regarding the latter topic). It should be noted that a significant number of atmospheric chemistry analyses that are published are based on “traditional” or standardized analytical approaches and are therefore outside the ambit of this Review on developments in the field, except where there are new aspects to the methodology or in the application thereof.Recent publications dealing with the monitoring of the atmosphere have covered analytes ranging from those that are commonly regulated, such as inorganic gases (SO2 and NOx), to those that can be considered emerging chemical pollutants (ECPs). These are typically defined as compounds that may have an impact on human health or the environment but do not currently have regulatory status.(6) The compounds thus falling within this definition vary across countries with differing legislative frameworks. On the basis of recent publications, the development of new techniques to monitor atmospheric levels of ammonia, flame retardants, polycyclic aromatic hydrocarbons, bioaerosols, and secondary organic aerosols (SOAs) have received much attention. SOAs are formed through the oxidation of volatile organic compounds and are comprised of thousands of compounds, posing extreme challenges to their characterization. Similarly, methods are being developed for the determination of radical species in the atmosphere, such as the use of fluorescence assay by gas expansion (FAGE) for methyl peroxy (CH3O2) radicals,(7) where the reactivity of these species presents significant challenges in sample handling and analysis. Developments in the field of atmospheric chemistry monitoring have been facilitated by improvements in the selectivity and sensitivity of analytical methods, while time, labor, and cost savings as well as a reduction in environmental impacts (green chemistry approaches) have also stimulated progress.Fouquet, T.N.J., 2019. The Kendrick analysis for polymer mass spectrometry. Journal of Mass Spectrometry 54, 933-947. mass spectrum of a polymer often displays repetitive patterns with peak series spaced by the repeating unit(s) of the polymeric backbones, sometimes complexified with different adducts, chain terminations, or charge states. Exploring the complex mass spectral data or filtering the unwanted signal is tedious whether performed manually or automatically. In contrast, the now 60-year-old Kendrick (mass defect) analysis, when adapted to polymer ions, produces visual two-dimensional maps with intuitive alignments of the repetitive patterns and favourable deconvolution of features overlaid in the one-dimensional mass spectrum. This special feature article reports on an up-to-date and theoretically sound use of Kendrick plots as a data processing tool. The approach requires no prior knowledge of the sample but offers promising dynamic capabilities for visualizing, filtering, and sometimes assigning congested mass spectra. Examples of applications of the approach to polymers are discussed throughout the text, but the same tools can be readily extended to other applications, including the analysis of polymers present as pollutants/contaminants, and to other analytes incorporating a repetitive moiety, for example, oils or lipids. In each of these instances, data processing can benefit from the application of an updated and interactive Kendrick analysis.Francis, S., Passow, U., 2020. Transport of dispersed oil compounds to the seafloor by sinking phytoplankton aggregates: A modeling study. Deep Sea Research Part I: Oceanographic Research Papers 156, 103192. to 20% of the oil spilled as a result of the Deepwater Horizon explosion in the Gulf of Mexico in 2010 was deposited as degraded oil compounds on the seafloor. Much of that deposition was likely due to dispersed oil compounds having been integrated into fast-sinking aggregates, which transported it effectively to depth. Understanding the details of this oil transport mechanism, and predicting its potential magnitude, is important for the management and mitigation of future oil spills.The 1-D model described here simulates a) a diatom bloom and the resulting formation of aggregates via coagulation of cells, b) the scavenging of dispersed oil compounds by these aggregates as they sink through the water column, c) the degradation of diatom carbon and oil carbon during transit, and d) the ultimate deposition of aggregates and oil compounds to the seafloor. The model is parameterized using primarily field- and laboratory-collected data and the model results are compared to sediment trap data. Specifically, one large diatom sedimentation event observed shortly after the Deepwater well was capped was modeled. The comparison of simulation results to field data assesses the model’s ability to explain the observed sedimentation event and tests our understanding of the main mechanisms driving such an event.The model results indicate that diatom carbon and oil compounds captured in the trap were linked to a sedimentation event that reached peak intensity just before the trap was deployed. The model simulations predict the measured sedimentation rates of oil compounds and organic carbon reasonably well, indicating that the key mechanisms driving this process were captured by the model. In the baseline case, which simulates the sedimentation of a large Skeletonema bloom in late August 2010, about 10% of the dispersed oil compounds lingering in the water were deposited to the seafloor. The ability of a sinking diatom bloom to scavenge dispersed oil compounds from the water column and deposit them to depth is a robust result of the model over a range of parameter variations. These results suggest that a model that combines satellite data on phytoplankton blooms with water column dispersed oil concentrations to estimate potential oil compound deposistion rates may be able to provide decision makers with guidance during an oil spill. However, additional, independent validation of the model is necessary before it can be adapted for use in an operational setting.Franklin, H.M., Carroll, A.R., Chen, C., Maxwell, P., Burford, M.A., 2020. Plant source and soil interact to determine characteristics of dissolved organic matter leached into waterways from riparian leaf litter. Science of The Total Environment 703, 134530. of leaf litter accumulated in riparian zones during rainfall events provides pulses of dissolved organic matter (DOM) to rivers. Restoring riparian vegetation aims to reduce sediment and nutrient transport into rivers, however DOM from leaf litter can stimulate phytoplankton growth and interfere with water treatment processes. Improved understanding of the loads and chemical composition of DOM leached from leaf litter of different plant species, and how subsequent leaching through soils affects DOM retention or transformation, is needed to predict the outcomes of riparian revegetation. To investigate this, we simulated rapid leaching of rainfall through the leaf litter of two riparian tree species with and without subsequent leaching through soil, comparing dissolved organic carbon (DOC) and nitrogen (DON) loads, and DOM chemical composition (via spectroscopic and novel NMR-fingerprinting techniques). Plant source affected the load and composition of DOM leaching, with Eucalyptus tereticornis leaching more DOC than Casuarina cunninghamiana. Additionally, E. tereticornis DOM had a higher sugar, myo-inositol, benzoic acid, flavonoid and oxygenated aromatic content. More than 90% of leaf litter DOM was retained in the soil under simulated repeated heavy rainfall. The DOM chemistry of these species determined the total loads and changes in DOM composition leaching through soil. Less E. tereticornis DOM was retained by the soil than C. cunninghamiana DOM, with sugars, myo-inositol and amino acids being poorly retained compared to fatty acids and aromatic compounds. It also appears that DOM from E. tereticornis litter primed the soil, resulting in more DON being leached compared with bare soil. In comparison, C. cunninghamiana litter resulted in greater retention of DON, oxygenated aromatic compounds and the amino acid tryptophan. This study provides new information on how a range of DOM sources and transformations affect the DOM ultimately leached into waterways, key to developing improved models of DOM transformations in catchments.French, D.E., Trexler Jr., J.H., Cashman, P.H., Walker, J.P., Wylie Jr., A.S., 2020. Mississippian mud rocks of the eastern Great Basin: Stratigraphy, tectonic significance, and hydrocarbon potential. American Association of Petroleum Geologists Bulletin 104, 387-410. thick succession of Mississippian mud rocks in the eastern Great Basin has historically been identified as the Chainman Shale and interpreted as a foreland basin deposit associated with the Antler orogeny. Our work shows that this section is two distinct mud-rock units separated by a Late Mississippian unconformity. The Gap Wash Formation is identified as the mud rock below the unconformity, and Chainman Shale is restricted to mud rock above the unconformity. Poor exposure, sparse age control, and limited lithologic contrast have hampered identification and correlation of the mud-rock units. New research identifies subtle differences in rock type, and mineralogical and source-rock analyses show that the two formations have contrasting characteristics. These are associated with petrophysical properties that can be correlated across the region. The data show that the Gap Wash Formation has significantly more organic carbon and better pyrolysis results than the Chainman Shale. The Gap Wash also has mineralogy that could make it more suitable for treatment as a shale reservoir. The new understanding of Mississippian mud rocks in the Great Basin can focus future hydrocarbon exploration. The mud-rock units record regional Mississippian paleogeographic evolution. The Gap Wash Formation was deposited into accommodation space created by the loading of the continental margin during the Antler orogeny. The Chainman Shale was deposited in a successor basin that formed in response to resumed continental margin contraction in the late Meramecian to early Chesterian and is not clearly associated with the Antler orogeny.Fryer, P., Wheat, C.G., Williams, T., Kelley, C., Johnson, K., Ryan, J., Kurz, W., Shervais, J., Albers, E., Bekins, B., Debret, B., Deng, J., Dong, Y., Eickenbusch, P., Frery, E., Ichiyama, Y., Johnston, R., Kevorkian, R., Magalhaes, V., Mantovanelli, S., Menapace, W., Menzies, C., Michibayashi, K., Moyer, C., Mullane, K., Park, J.-W., Price, R., Sissmann, O., Suzuki, S., Takai, K., Walter, B., Zhang, R., Amon, D., Glickson, D., Pomponi, S., 2020. Mariana serpentinite mud volcanism exhumes subducted seamount materials: implications for the origin of life. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20180425. subduction of seamounts and ridge features at convergent plate boundaries plays an important role in the deformation of the overriding plate and influences geochemical cycling and associated biological processes. Active serpentinization of forearc mantle and serpentinite mud volcanism on the Mariana forearc (between the trench and active volcanic arc) provides windows on subduction processes. ?Here, we present (1) the first observation of an extensive exposure of an undeformed Cretaceous seamount currently being subducted at the Mariana Trench inner slope; (2) vertical deformation of the forearc region related to subduction of Pacific Plate seamounts and thickened crust; (3) recovered Ocean Drilling Program and International Ocean Discovery Program cores of serpentinite mudflows that confirm exhumation of various Pacific Plate lithologies, including subducted reef limestone; (4) petrologic, geochemical and paleontological data from the cores that show that Pacific Plate seamount exhumation covers greater spatial and temporal extents; (5) the inference that microbial communities associated with serpentinite mud volcanism may also be exhumed from the subducted plate seafloor and/or seamounts; and (6) the implications for effects of these processes with regard to evolution of life.Fu, L., Li, D., Mi, T., Zhao, J., Liu, C., Sun, C., Zhen, Y., 2020. Characteristics of the archaeal and bacterial communities in core sediments from Southern Yap Trench via in situ sampling by the manned submersible Jiaolong. Science of The Total Environment 703, 134884. hadal environment is the deepest part of the ocean and harbors a significant number of unique microbial communities. Here, we collected core sediment samples of Southern Yap Trench with the deep-sea manned submersible Jiaolong and analyzed the microbial community structure and abundance in the samples through high-throughput sequencing and real-time fluorescence quantitative PCR (qPCR), taking physicochemical parameters into account to explore potential environmental drivers and metabolic pathways therein. Considering the typical “V-shape” topography and frequent sediment collapses on trench walls, the core sediments of Southern Yap Trench harbored distinct microbial populations with fluctuating distributions and metabolic processes dominated by Proteobacteria and Thaumarchaeota. To discover the main potential metabolic processes of microbes, functional genes were detected by qPCR. The abundance of bacteria was greater than that of archaea in Southern Yap Trench sediments. The abundance of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), sulfate-reducing bacteria (SRB) and denitrifying bacteria (denitrifier) decreased with increasing depth and decreasing total organic carbon (TOC%) and total nitrogen (TN%) and showed a positive and significant correlation with TOC% (P?<?0.01), TN% (P?<?0.01), TOC/TN molar ratio (C/N ratio) (P?<?0.01) and median grain size (P?<?0.01). From the perspective of function based on the 16S rRNA gene, aerobic ammonium oxidization, carbon assimilation, and chemoheterotrophic function may be the dominant processes in Southern Yap Trench sediments. Moreover, considering the isolated geomorphological and hydrological characteristics of Southern Yap Trench, we hypothesized that the distinct hadal microbial ecosystem was driven by the endogenous recycling of organic matter in the hadal sediments associated with the trench geomorphology.Fu, Y., Chen, Z., Zhou, S., Wei, S., 2020. Comparative study of the materials and lacquering techniques of the lacquer objects from Warring States Period China. Journal of Archaeological Science 114, 105060. recent decades, a number of important high quality lacquer objects have been excavated from archaeological sites dating to the Warring States Period (481-221 BC), indicating the significance of the lacquer objects in that time. In order to better understand the lacquering techniques in this period, two types of lacquer objects from the Jiuliandun tomb were studied by using thermally assisted hydrolysis–methylation pyrolysis-gas chromatography/mass spectrometry (THM-Py-GC/MS), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy/energy dispersive X-ray spectrometry (SEM-EDS). The results revealed that a multi-layer lacquering technique was used to create the lacquer objects. Urushiol and drying oils were identified in the pigmented surface finish layer and lacquer layer, but different drying oils were identified in the ear cups and box, respectively. In addition, blood was found in the ground layer of ear cups. The results were compared with the lacquer objects from other Chu tomb, indicating that a variety of lacquering techniques were used during the Warring States period, perhaps depending on the different functions of the lacquer objects or simply reflecting different traditions.Gao, P., He, Z., Lash, G.G., Li, S., Zhang, R., 2020. Origin of chert nodules in the Ediacaran Doushantuo Formation black shales from Yangtze Block, South China. Marine and Petroleum Geology 114, 104227. nodules are widely developed in Ediacaran deposits of South China, yet the mechanism responsible for their formation remains disputed. Petrological and geochemical studies of chert nodules and host shale of the Ediacaran Doushantuo Formation of the Yangtze Block, South China, were carried out to more fully assess silicification of these deposits. Doushantuo chert nodules display a concentrically layered internal structure dominated by quartz and lesser concentrations of calcite, carbonate fluorapatite, organic matter, pyrite, and sphalerite. Individual layers become thinner from nodule centers to edges. Our results suggest that (1) Doushantuo host black shale accumulated under persistent anoxic bottom water conditions and (2) chert nodules formed as a consequence of the anaerobic oxidation of methane focused along sulfate-methane transition zones at shallow burial depth. Nodules likely originated from porous proto-nodules that consisted of 13C-depleted authigenic calcite produced by the anaerobic oxidation of methane. Decaying of organic matter within nodules helped to create porosity that was filled by authigenic calcite and also released phosphate and zinc ions to pore water, thus favoring precipitation of carbonate fluorapatite and sphalerite. Silica supplied principally from the diagenesis of clay minerals of the host shale cemented the nodules and replaced early formed calcite. The progressive infilling of residual porosity by 18O-depleted pore fluids associated with increasing burial depth is reflected in the strongly negative δ18Ocarb values documented from the nodules. Thus, the formation of Doushantuo chert nodules reflects a protracted diagenetic history initiated by bacterial sulfate reduction and anaerobic oxidation of methane close to and within the sulfate-methane transition zone and continued in association with the diagenetic release of silica from host shale as well hydrocarbon generation with increasing burial depth.Garwood, R.J., Oliver, H., Spencer, A.R.T., 2020. An introduction to the Rhynie chert. Geological Magazine 157, 47-64. terrestrialization of life has profoundly affected the biosphere, geosphere and atmosphere, and the Geological Magazine has published key works charting the development of our understanding of this process. Integral to this understanding – and featuring in one of the Geological Magazine publications – is the Devonian Rhynie chert Konservat-Lagerst?tte located in Aberdeenshire, Scotland. Here we provide a review of the work on this important early terrestrial deposit to date. We begin by highlighting contributions of note in the Geological Magazine improving understanding of terrestrialization and Palaeozoic terrestrial ecosystems. We then introduce the Rhynie chert. The review highlights its geological setting: the Caledonian context of the Rhynie Basin and its nature at the time of deposition of the cherts which host its famous fossils. There follows an introduction to the development of the half-graben in which the cherts and host sediments were deposited, the palaeoenvironment this represented and the taphonomy of the fossils themselves. We subsequently provide an overview of the mineralization and geochemistry of the deposit, and then the fossils found within the Rhynie chert. These include: six plant genera, which continue to provide significant insights into the evolution of life on land; a range of different fungi, with recent work starting to probe plant–fungus interactions; lichens, amoebae and a range of unicellular eukaryotes and prokaryotes (algae and cyanobacteria); and finally a range of both aquatic and terrestrial arthropods. Through continued study coupled with methodological advances, Rhynie fossils will continue to provide unique insights into early life on land.Gatchell, M., 2020. A new take on circumstellar carbon chemistry. Nature Astronomy 4, 21-22. years, much of our understanding of the formation of circumstellar aromatic molecules has been based on laboratory flame studies. Now, results acquired using a novel experimental technique suggest that circumstellar aromatics might not be formed under the conditions we thought they were.Gautier, T., Danger, G., Mousis, O., Duvernay, F., Vuitton, V., Flandinet, L., Thissen, R., Orthous-Daunay, F.R., Ruf, A., Chiavassa, T., d'Hendecourt, L.S., 2020. Laboratory experiments to unveil the molecular reactivity occurring during the processing of ices in the protosolar nebula. Earth and Planetary Science Letters 531, 116011. laboratory experiments, we investigate the role of photo and thermal degradation in the possible complexification mechanisms of organic matter that may originate from interstellar ices prior to, or during the formation of the Solar System. We perform High Resolution Orbitrap Mass Spectrometry on organic residues formed from the photo- and thermochemical alterations of Interstellar Medium (ISM) dirty ice laboratory analogues. We probe, at the molecular level, the possible effects within the protosolar nebula on the composition and structure of these organic refractory materials obtained from an initial ice composition representative of astrophysical ices. We show that nitrogen incorporation, by competing with the carbon, has a strong influence on the final composition of the residue. NH3 rich ices lead to a group of unsaturated molecules in the final residue, while H2O rich ices lead to saturated ones. Finally, we observe and discuss the strong effect of UV irradiation on the decarboxylation on organic matter and discuss potential implications of this result for the protosolar nebula.Gdara, I., Zrafi, I., Balducci, C., Cecinato, A., Ghrabi, A., 2020. First investigation of seasonal concentration behaviors and sources assessment of aliphatic hydrocarbon in waters and sediments from Wadi El Bey, Tunisia. Archives of Environmental Contamination and Toxicology 78, 1-19. contents, composition profiles, and sources of aliphatic hydrocarbons were examined in surface sediment and water samples collected from Wadi El Bey, in Tunisia, during different year seasons in 14 stations receiving domestic effluent, industrial discharge, and agricultural drainage wastes. The target substances were analyzed by gas chromatography coupled with mass spectrometric detection (GC/MS). Total concentrations of n-alkanes (n-C14-n-C38) ranged from 0.08?±?0.01 to 18.14?±?0.1 ?g/L in waters and 0.22?±?0.04 to 31.9?±?24.6 ?g/g in sediments, while total aliphatic fraction ranged from 0.08?±?0.01 to 196?±?140 ?g/L in waters and 0.22?±?0.04 to 1977?±?1219 ?g/g in sediments, which means that almost all sites were affected by hydrocarbon contents in sediments exceeding the recommended limit (100 ?g/g). Various diagnostic indices (ADIs) were used to identify the hydrocarbon sources, namely the concentration ratios of individual compounds (n-C17/pristane, n-C18/phytane, pristane/phytane, n-C29/n-C17, n-C31/n-C19) as well as cumulative quantities (Carbon Preference Index, natural n-alkanes ratio, terrigenous/aquatic compounds ratio, unresolved complex mixture percentage, low molecular weight vs. high molecular weight homologues, Alkane Proxy and Terrestrial Marine Discriminants). In general, these indexes indicated that the origin of aliphatic hydrocarbons affecting sediments and waters of Wadi El Bey were linked to both biogenic and petrogenic inputs, attesting the impact of plankton and terrestrial plants and of oil contamination, respectively. The average carbon chain length computation (ACL), used to further index the chemical environment, ranged from 25.5 to 31.1 in sediments and 47.9–116 in waters. This finding could depend on the severe disturbances suffered by the ecosystem as a consequence of heavy anthropogenic inputs. Petroleum contamination associated with high eutrophication rates in Wadi El Bey must be strictly controlled, due to possible harmful effects induced on ecosystem and humans.Ge, T., Xue, Y., Jiang, X., Zou, L., Wang, X., 2020. Sources and radiocarbon ages of organic carbon in different grain size fractions of Yellow River-transported particles and coastal sediments. Chemical Geology 534, 119452. elemental (TOC, TN and C/N) and carbon isotope (Δ14C and δ13C) compositions of organic matter were measured in different grain size fractions of particles transported by the Yellow River and surface sediments in the Bohai Sea and the Yellow Sea. In the riverine particle and sediment samples, high OC contents were associated with small grain size fractions consisting mainly of clay minerals. The δ13C and Δ14C values of the bulk riverine particulate organic carbon (POC) collected from the Lijin and Xiaolangdi sites were relatively constant but varied significantly (?21.9‰ to ?26.0‰ and ?325‰ to ?620‰, respectively) among the different size fractions. In comparison, large spatial variations in δ13C (?20.6‰ to ?24.5‰) and Δ14C (?188‰ to ?646‰) values, which increased seaward due to the difference in source carbon, were found for bulk TOC Δ14C preserved in the surface sediments, but no significant differences were observed among the values in the different size fractions in most sediments. The different carbon isotopic values of the riverine POC and sedimentary TOC reflect differences in the sources, degradation and cycling time scales of the OC. The Yellow River exports very old (5220 ± 295 yrs) POC that is much older than the TOC (2457 ± 676 yrs) preserved in the surface sediments in the Bohai and Yellow seas. Calculations using a dual-isotope three end-member model indicate that pre-aged soil OC and ancient fossil OC represent major proportions (57 ± 16% and 30 ± 8%, respectively) of the riverine POC and that terrestrial biomass OC represents a minor proportion (13 ± 11%). The drainage environment of the river plays important roles in controlling the sources and ages of the riverine POC. In contrast, the TOC in the grain size fractions of the surface sediments in the Bohai and Yellow seas is dominated by marine-derived modern OC (47 ± 13%), followed by pre-aged soil OC (29 ± 9%) and ancient fossil OC (25 ± 14%). The ages of the TOC are determined mainly by the source input, rapid sedimentation, sediment minerology and decomposition of OC during early diagenesis in these large river-influenced marginal seas.Ge, X., Shen, C., Selby, D., Feely, M., Zhu, G., 2020. Petroleum evolution within the Tarim Basin, northwestern China: Insights from organic geochemistry, fluid inclusions, and rhenium–osmium geochronology of the Halahatang oil field. American Association of Petroleum Geologists Bulletin 104, 329-355. newly discovered Halahatang oil field in the northern Tarim Basin has a potential resource of more than 70 billion bbl of oil. Oil organic geochemical data from the Halahatang oil field indicate that the oils are of moderate maturity, biodegraded, and represent one oil family, derived from the same Paleozoic marine source. Modeling of coeval aqueous and hydrocarbon-bearing inclusion data provide fluid trapping temperatures and pressures of 100°C to 110°C and approximately 39 to 59 MPa (～5656–8557 psi), respectively. The fluid inclusion data coupled with the previous basin model studies suggest a single prolonged oil migration event during the Permian. The Re–Os isotope data of the oil yields an early Permian Re–Os age of 285 ± 48 Ma. The age agrees with the timing of maturation of the Paleozoic source via burial history modeling but is slightly older (～5–55 m.y.) than the oil migration and accumulation timing implied by the basin modeling coupled with fluid inclusion analysis and the published reservoir illite K–Ar dates. Thus, the oil Re–Os date suggests that oil generation in the Halahatang depression of the Tarim Basin occurred during the early Permian rather than the Silurian as previously proposed, with subsequent oil migration and accumulation occurring during the middle–late Permian as recorded by basin modeling, coupled with fluid inclusion analysis and illite K–Ar dating. In addition to promoting petroleum exploration in the Tarim Basin, this study, which combines crude oil Re–Os isotope dating and traditional analytical methods (organic geochemistry and fluid inclusion analysis) to constrain petroleum evolution, is applicable to hydrocarbon systems worldwide.Ghosh, A.K., Bandopadhyay, A.K., 2020. Formation of thermogenic gases with coalification: FTIR and DFT examination of vitrinite rich coals. International Journal of Coal Geology 219, 103379. evolution of thermogenic gases during coalification has not yet been theoretically attempted. Examinations on Indian Permian vitrinites of various ranks ranging from Cwt% 76 to 92 were performed. Fourier Transform Infra-red spectroscopy (FTIR) provided insight into the structural changes where the aliphatic CH increases with increase in percentage of carbon up to ~85% and then decreases. In contrast, the aromatic CH, the ratio of aromatic CH to aliphatic CH and aromaticity (fa) increase monotonically with the advancement of rank. A relationship between fa and atomic H/C ratio as fa = 1.12–0.45H/C was established to predict fa from elemental analysis. The structural data from FTIR served as an input to construct six representative hypothetical models of coal of varying Cwt% (76, 80, 83, 86, 87 and 89). Density Functional Theory (DFT) has been applied to these coal models and the formation of principal thermogenic gases, viz. CO2 for the low-(76%C)and CH4 for the high-rank (87%C), with simultaneous increase in the rank was demonstrated considering the smaller structural units extracted from the relevant coal models. The suggested reaction pathways are supported by the negative values of changes in free energies of the reactions computed from the Gaussian thermo-chemistry. The studies could, therefore, show that gas evolution as a natural (spontaneous) process with feasibility of rank advancement.Giner, C.R., Pernice, M.C., Balagué, V., Duarte, C.M., Gasol, J.M., Logares, R., Massana, R., 2020. Marked changes in diversity and relative activity of picoeukaryotes with depth in the world ocean. The ISME Journal 14, 437-449. eukaryotes are key components of the ocean plankton. Yet, our understanding of their community composition and activity in different water layers of the ocean is limited, particularly for picoeukaryotes (0.2–3??m cell size). Here, we examined the picoeukaryotic communities inhabiting different vertical zones of the tropical and subtropical global ocean: surface, deep chlorophyll maximum, mesopelagic (including the deep scattering layer and oxygen minimum zones), and bathypelagic. Communities were analysed by high-tthroughput sequencing of the 18S rRNA gene (V4 region) as represented by DNA (community structure) and RNA (metabolism), followed by delineation of Operational Taxonomic Units (OTUs) at 99% similarity. We found a stratification of the picoeukaryotic communities along the water column, with assemblages corresponding to the sunlit and dark ocean. Specific taxonomic groups either increased (e.g., Chrysophyceae or Bicosoecida) or decreased (e.g., Dinoflagellata or MAST-3) in abundance with depth. We used the rRNA:rDNA ratio of each OTU as a proxy of metabolic activity. The highest relative activity was found in the mesopelagic layer for most taxonomic groups, and the lowest in the bathypelagic. Altogether, we characterize the change in community structure and metabolic activity of picoeukaryotes with depth in the global ocean, suggesting a hotspot of activity in the mesopelagic.Ginting, E.L., Kemer, K., Wullur, S., Uria, A.R., 2020. Identification of proteolytic thermophiles from Moinit Coastal Hot-Spring, North Sulawesi, Indonesia. Geomicrobiology Journal 37, 50-58. have isolated thermophilic bacteria from Moinit coastal hot-spring, North Sulawesi, Indonesia. Of 12 seawater samples collected, we obtained 20 thermophilic bacterial isolates. Sixteen of the isolated thermophiles were found to exhibit protein-degrading ability as indicated by the presence of clearing zones surrounding their colonies on skim milk-containing plates at 65?°C. Five of them with larger proteolytic indexes, designated as 2b, 4b, 9a, 9b, and 12L, were selected for further studies. The ability of these five strains to hydrolyze casein at high temperatures was indicated by relatively high activity of their extracellular proteases at 60?°C. Partial protease-encoding genes were amplified from each isolated strain and sequenced. Further bioinformatics analysis suggests that the extracellular proteases that they produced belong to serine proteases. The integrated morphological, biochemical, and genetic analyses showed the identity of the strains 2b, 4b, and 9a as members of Bacillus, 9b as Pseudomonas, and 12L as Aneurinibacillus. To the best of our knowledge, so far thermophilic Pseudomonas and Aneurinibacillus remain poorly investigated in term of extracellular protease production, suggesting the biotechnological potential of the strains 9b and 12L as the producer of a unique extracellular thermostable protease.Gnida, A., 2020. What do we know about the influence of vacuum on bacterial biocenosis used in environmental biotechnologies? Applied Microbiology and Biotechnology 104, 101-106. article aims to show the increased interest in the applications of vacuum in the area of environmental biotechnology and the lack of research related to the effects of vacuum on bacteria and microbial communities. Information on the impact of vacuum on bacteria is limited and often comes from unrelated research fields. In most cases (astrobiology research, food preservation technologies), the exposure of microorganisms in vacuum is permanent for the whole life of a cell. In environmental science applications, the exposure of microorganisms containing media such as sludge or soil in vacuum is rather persistent, and lower values of vacuum are used. Vacuum is used or proposed to be used in wastewater treatment, anaerobic digestion, sludge treatment, soil remediation and mining. Usually, vacuum is used to remove gases from the test medium, so a purely physical process is applied. However, most reports show the influence of vacuum on biological processes and its efficiency, as well as on the community structure.González-Riano, C., Dudzik, D., Garcia, A., Gil-de-la-Fuente, A., Gradillas, A., Godzien, J., López-Gonzálvez, ?., Rey-Stolle, F., Rojo, D., Ruperez, F.J., Saiz, J., Barbas, C., 2020. Recent developments along the analytical process for metabolomics workflows. Analytical Chemistry 92, 203-226. are in the midst of a shift in biological research paradigms from reductionist methodologies that generate a hypothesis and rigorously and quantitatively measure the selected variables to “omics” technologies that measure all of the components in a set in a holistic way and detect variations in compounds between two or more conditions. Among “omics” technologies, metabolomics is one in which analytical developments have had a profound impact due to the diverse physicochemical properties of metabolites and their different concentration ranges, which require more robust analytical strategies. According to the Working Party on Analytical Chemistry of the European Federation of Chemical Societies, “Analytical Chemistry is a scientific discipline that develops and applies methods, instruments, and strategies to obtain information on the composition and nature of matter in space and time”, and the aims of metabolomics fully overlap with the aims of analytical chemistry.(1) However, it seems that metabolomics, and in particular untargeted metabolomics, is disrupting the status quo of the field of analytical chemistry, which for years has focused on developing tools to achieve the most accurate quantification of compounds and is not easily accepting of semiquantitative analyses. In contrast, tools and principles should be developed to make this type of analysis as reliable as possible. Furthermore, quality management, which is broadly adapted from quality assurance (QA) and quality control (QC) guidelines set by analytical chemistry, has already been established as an integral part of metabolomics studies. Our previous work addressed preanalytical, analytical, and postanalytical challenges and provided a comprehensive review of the tools and solutions for controlling every analytical component of untargeted metabolomics workflows.(2) The aim of this review is to follow the main steps of the analytical chemistry process in parallel with recent developments in metabolomics workflows to critically describe how new analytical tools based on separation techniques coupled with mass spectrometry are contributing to both approaches. The first step in every analytical process is developing a clear and complete definition of the objective of the analysis, which will define the type of sample, the number of samples, the groups to be compared, and many other factors. As this step is quite case dependent, we will focus on the following steps: (i) recent developments in sample collection and preparation, (ii) recent developments in analytical tools, and (iii) new trends in data mining strategies and in the identification of compounds. Data interpretation, which is also a key part of both metabolomics and analytical processes, will not be included due to limitations on the length of the manuscript.Goodman, A., Sanguinito, S., Kutchko, B., Natesakhawat, S., Cvetic, P., Allen, A.J., 2020. Shale pore alteration: Potential implications for hydrocarbon extraction and CO2 storage. Fuel 265, 116930. unconventional reservoirs are currently and expected to remain substantial fossil fuel resources in the future. As CO2 is being considered to enhance oil recovery and for storage purposes in unconventional reservoirs, it is unclear how the shale matrix and fractures will react with CO2 and water during these efforts. Here, we examined the Utica Shale and its reactivity with CO2 and water using scanning electron microscopy, N2 and CO2 sorption isotherms, mercury intrusion porosimetry, and X-ray scattering methods. During CO2 exposure, the presence of water can inhibit CO2 migration into the shale matrix, promote carbonate dissolution, and dramatically change the pore scale variability by opening and closing pore networks over the macro- to nano-scale range. These alterations in the shale matrix could impact flow pathways and ultimately, oil recovery factors and carbon storage potential.Goral, J., Panja, P., Deo, M., Andrew, M., Linden, S., Schwarz, J.-O., Wiegmann, A., 2020. Confinement effect on porosity and permeability of shales. Scientific Reports 10, 49. and permeability are the key factors in assessing the hydrocarbon productivity of unconventional (shale) reservoirs, which are complex in nature due to their heterogeneous mineralogy and poorly connected nano- and micro-pore systems. Experimental efforts to measure these petrophysical properties posse many limitations, because they often take weeks to complete and are difficult to reproduce. Alternatively, numerical simulations can be conducted in digital rock 3D models reconstructed from image datasets acquired via e.g., nanoscale-resolution focused ion beam–scanning electron microscopy (FIB-SEM) nano-tomography. In this study, impact of reservoir confinement (stress) on porosity and permeability of shales was investigated using two digital rock 3D models, which represented nanoporous organic/mineral microstructure of the Marcellus Shale. Five stress scenarios were simulated for different depths (2,000–6,000 feet) within the production interval of a typical oil/gas reservoir within the Marcellus Shale play. Porosity and permeability of the pre- and post-compression digital rock 3D models were calculated and compared. A minimal effect of stress on porosity and permeability was observed in both 3D models. These results have direct implications in determining the oil-/gas-in-place and assessing the production potential of a shale reservoir under various stress conditions.Gordin, Y., Hatzor, Y.H., Vinegar, H.J., 2020. Anisotropy evolution during early maturation of organic-rich carbonates. Journal of Petroleum Science and Engineering 188, 106946. organic-rich Late Cretaceous carbonates of the Ghareb and Mishash formations are potentially both self-sourced unconventional reservoirs and high quality source rocks for conventional petroleum systems in the eastern Mediterranean region. In this study we use cores from depths ranging from 340 to 1290 m in the Shefela and Golan Heights basins in Israel, which records the diagenesis and transformation phases of organic-rich chalk into limestone. Understanding such source rocks is complicated by the fact that each formation is unique and heterogeneity is common within each formation. Moreover, in situ samples at various stages of maturation are rarely available. We apply the three-plug measuring technique for a vertical transversely isotropic (VTI) medium to investigate the ultrasonic wave velocity and permeability anisotropies of organic-rich chalks (ORC) within the tested sequence.We propose that in ORC diagenesis, the characteristics and distribution of the organic matter in the rock matrix change significantly throughout burial and thermal maturation, strongly affecting the velocities. Measuring the velocity hysteresis under varying confining pressures revealed that development of soft porosity with preferred orientation plays a crucial role in the early maturation stage (TMAX of 428–434°C), particularly under low effective stresses, while it is absent in the immature stage (TMAX of 403–415°C). The sensitivity of the wave velocities at low effective stresses results in variations in velocity anisotropy, which may potentially be utilized in seismic exploration to delineate the highly-pressured ‘sweet spots’ in unconventional organic-rich carbonates.Gorman, B.L., Kraft, M.L., 2020. High-resolution secondary ion mass spectrometry analysis of cell membranes. Analytical Chemistry 92, 1645-1652. Feature describes the use a Cameca NanoSIMS instrument for directly imaging specific lipid and protein species in the plasma membranes of mammalian cells with approximately 100 nm-lateral resolution and discusses how these analyses have already begun to transform fundamental concepts in the field of membrane biology. Secondary ion generation is discussed with emphasis on the constraints that affect the detection and identification of membrane components, and then the sample preparation methodologies and data analysis strategies that address these constraints are described.Grandy, J.J., Onat, B., Tunnicliffe, V., Butterfield, D.A., Pawliszyn, J., 2020. Unique solid phase microextraction sampler reveals distinctive biogeochemical profiles among various deep-sea hydrothermal vents. Scientific Reports 10, 1360. methods for biochemical and biogeochemical analysis of the deep-sea hydrothermal vent ecosystems rely on water sample recovery, or in situ analysis using underwater instruments with limited range of analyte detection and limited sensitivity. Even in cases where large quantities of sample are recovered, labile dissolved organic compounds may not be detected due to time delays between sampling and preservation. Here, we present a novel approach for in situ extraction of organic compounds from hydrothermal vent fluids through a unique solid phase microextraction (SPME) sampler. These samplers were deployed to sample effluent of vents on sulphide chimneys, located on Axial Seamount in the North-East Pacific, in the Urashima field on the southern Mariana back-arc, and at the Hafa Adai site in the central Mariana back-arc. Among the compounds that were extracted, a wide range of unique organic compounds, including labile dissolved organic sulfur compounds, were detected through high-resolution LC-MS/MS, among which were biomarkers of anammox bacteria, fungi, and lower animals. This report is the first to show that SPME can contribute to a broader understanding of deep sea ecology and biogeochemical cycles in hydrothermal vent ecosystems.Grazhdankin, D.V., Marusin, V.V., Izokh, O.P., Karlova, G.A., Kochnev, B.B., Markov, G.E., Nagovitsin, K.E., Sarsembaev, Z., Peek, S., Cui, H., Kaufman, A.J., 2020. Quo vadis, Tommotian? Geological Magazine 157, 22-34. concept of the Tommotian Regional Stage of the Siberian Platform has been closely linked to the idea of the ‘Cambrian Explosion’ of animals and protists when the entire Earth system shifted rapidly into Phanerozoic mode. We conducted a multidisciplinary study of an informal ‘synstratotype’ of the lower Tommotian boundary in the upper Mattaia Formation, Kessyusa Group in the Olenek Uplift, NE of the Siberian Platform. The Mattaia Formation characterizes an upper shoreface to inner-shelf depositional setting and provides important faunal ties and correlation with carbonate-dominated and aliminosiliciclastic open-shelf areas. A section of the upper Mattaia Formation at Boroulakh, Olenek River is suggested here as a model for the Global Boundary Stratotype Section and Point for the base of the Cambrian Stage 2. This level contains the lowermost occurrence of the cosmopolitan fossil helcionelloid mollusc Aldanella attleborensis. Section global markers near the base of the stage include a positive excursion of δ13C values reaching +5.4‰, a U–Pb zircon date of 529.7 ± 0.3 Ma, massive appearance of diverse small skeletal fossils (including Watsonella crosbyi), a sudden increase in diversity and abundance of trace fossils, as well as a conspicuous increase in depth and intensity of bioturbation. Coincidently, it is this level that has always been regarded as the lower Tommotian boundary on the Olenek Uplift.Gribaldo, S., Brochier-Armanet, C., 2020. Evolutionary relationships between Archaea and eukaryotes. Nature Ecology & Evolution 4, 20-21. phylogenomic re-analysis of sequence data strongly supports the emergence of eukaryotes from within the archaeal radiation and underlines the importance of using the most accurate approaches to reconstruct ancient divergences in the tree of life.Griffiths, W., Wang, Y., 2020. Lipidomics: Current and Emerging Techniques New Developments in Mass Spectrometry. Royal Society of Chemistry, p. 288. is one of the emerging ‘omics’ techniques with growing importance in bioscience. Discussing interesting standard and non-standard techniques relevant to the measurement and analysis of lipids by mass spectrometry, this book will provide a guide to the possibilities of the techniques. It will introduce the reader to exciting new methods that allow isomer differentiation, improve sensitivity, allow spatial location and go beyond annotation of simply matching a mass to a database entry. The book is written and edited by the some of the world leaders in the field of lipid mass spectrometry and will have international appeal in industry and academia for analytical chemists, biochemists and biotechnologists. Furthermore, it will provide a useful resource for anyone interested in lipid structure characterization particularly for graduates and postgraduates who require a starting point for their projects.Chapter 1: Lipidomics Basics. W. J. Griffiths, E. Yutuc, D. Davies, A. Dickson, R. Angelini, D. El Assad, G. Frache and Y. Wang. Pages 1 - 24 Lipidomics can be regarded as the quantitative profiling of the entire lipid composition of a defined system, be that a cell, tissue, biofluid or intact organism. Lipidomics is a descendent of what was previously known as “metabolite profiling” and is a relative of the related “omic” disciplines of genomics, transcriptomics and proteomics. Lipidomics can be regarded as a sub-division of metabolomics. In this chapter we will discuss the current methodologies popular in lipidomics, highlighting gas-chromatography mass spectrometry (GC-MS), liquid-chromatography MS (LC-MS) and direct-infusion, also known as “shotgun” MS (DI-MS). We will also introduce newer methods including low-flow-rate-LC MS, ion mobility MS (IM-MS) and MS imaging (MSI), described in detail in later chapters. Chemical derivatisation is not a new idea to lipidomics; however, its use goes in and out of vogue, hence we also introduce some of its benefits and disadvantages here and in a later chapter.Chapter 2. Multivariate Statistics in Lipidomics. Julian L. Griffin, Sonia Liggi and Zoe Hall. Pages 25 - 48 In lipidomics the aim is to measure the concentration of every lipid above the limit of detection in a biofluid or tissue extract. By its very nature this produces large multivariate datasets where standard univariate statistical tools are inappropriate because of the problems of multiple testing and multiple co-variants. To address this there is increasing interest in the use of multivariate statistics and machine learning approaches to process the datasets obtained. In this chapter we will examine why multivariate statistical tools are often more appropriate than their univariate counterparts, and introduce some common unsupervised and supervised approaches used in lipidomics, including principal components analysis, hierarchical cluster analysis, partial least squares discriminate analysis and machine learning approaches such as random forests. The application of multivariate statistics will then be demonstrated in applications that produce one-dimensional (direct infusion mass spectrometry), two-dimensional (liquid chromatography mass spectrometry) and three-dimensional (mass spectrometry imaging, liquid chromatography ion mobility mass spectrometry) datasets as part of their lipidomic workflows.Chapter 3. Low-flow Rate Separations of Lipids. Hanne Roberg-Larsen and Steven Ray Wilson. Pages 49 - 73 Low-flow rate separation systems (e.g. nano liquid chromatography and capillary electrophoresis) can allow for enhanced sensitivity and/or resolution. Such systems can be used for detecting low-abundant lipids, performing lipidomics of very small amounts of sample, and for studying interactions between lipids and other compounds, e.g. drugs. Low-flow separation systems are highly compatible with mass spectrometry, on-line sample preparation, and multi-dimensional chromatography, for example.Chapter 4. Ion Mobility–Mass Spectrometry for Lipid Analysis. Giuseppe Paglia and Giuseppe Astarita. Pages 74 - 87 Ion mobility (IM) is a post ionization tool that can be used to separate lipid ions in the gas phase according to their charge, shape and size. IM can be combined with mass spectrometry (MS), adding three main benefits to traditional approaches for lipid analysis. First, IM allows determination of the collision cross section of a lipid molecule, a physicochemical property related to the conformational structure, which facilitates lipid identification. Second, IM improves the peak capacity and the signal-to-noise ratio, allowing the separation of interfering isobaric lipid species. Third, IM allows a new set of hybrid fragmentation experiments that combine collision-induced dissociation with gas phase separation, improving the specificity of the tandem MS-based approaches. Here, we review the current applications of IM-MS for lipid analysis.Chapter 5. Mass Spectrometry Imaging of Lipids. Shazia Khan and Ruth Andrew. Pages 88 - 121 Mass Spectrometry Imaging (MSI) has evolved as an exciting technology that can be used to map lipids on tissue surfaces, with many research, industrial and clinical applications. A wide variety of lipids can be spatially localised in both positive and negative modes (e.g. highlighted in cancer, skin and brain) and ionisation approaches such as Matrix-Assisted Laser Desorption/Ionisation (MALDI), Secondary Ion Mass Spectrometry (SIMS) and Desorption Electrospray Ionisation (DESI) bring different strengths and weaknesses, including mass ranges and resolution, fragmentation profiles and spatial resolution. This chapter explores the technical differences of the ionisation types applied to lipid MSI, and offers insight into appropriate choices for spatially profiling specific lipid classes. Novel approaches to enhance ionisation through derivatisation, matrix chemistry and nanomaterials offer the potential to reveal a greater proportion of the lipidome. MSI offers opportunities to profile lipid classes, but in the absence of chromatography cannot yet confidently assign stereochemistry, a weakness that may be addressed using ion mobility. Advances in integrating ion mobility and improvements in handling the large datasets generated, in combination with current methodologies, offer exciting future opportunities to decipher the complex lipid patterns in health and disease.Chapter 6. Derivatisation for Direct Infusion– and Liquid Chromatography–Mass Spectrometry. Y. Wang and W. J. Griffiths. Pages 122 - 147 The concept of derivatisation to enhance the ion signal is almost as old as biological mass spectrometry (MS) itself. In this chapter we will concentrate our attention on derivatisation methods to enhance ion signals in desorption ionisation methods, primarily matrix-assisted laser desorption/ionisation (MALDI) and electrospray ionisation (ESI), both for direct-infusion (DI)-MS and liquid chromatography (LC)-MS. Derivatisation provides advantages in lipidomics, as besides enhancing ion current can add specificity in terms of both solution chemistry and gas-phase ion chemistry via the collision-induced dissociation (CID) process. There are downsides to derivatisation methods, namely in terms of added complexity and time in sample preparation and the often unavoidable issues raised by excess derivatisation reagent and side reactions. As such, derivatisation methods tend to be exploited in groups with a chemistry background; however, the availability of reagents in kit format should facilitate the use of these methods by MS groups in general.Chapter 7. Unsaturated Lipid Analysis via Coupling the Paternò–Büchi Reaction with ESI-MS/MS. Xiaoxiao Ma and Yu Xia. Pages 148 - 174 Unsaturated lipids, which are characterized by the presence of one or multiple carbon–carbon double bonds (C=Cs) in fatty acyl/alkyl chains, constitute a significant proportion of all lipid species. Structural characterization and quantitation of unsaturated lipids, especially the location of unsaturation, is becoming increasingly important in lipid analysis. In this chapter, we introduce the combination of the Paternò–Büchi (PB) reaction, a fast (10–30 s) and highly specific C=C derivatization reaction with subsequent ESI-MS/MS for unsaturated lipid analysis. Upon low energy CID, the PB reaction products produce fragment ions specific to the original location of a C=C, allowing both structural identification and quantitation of unsaturated lipids. Acetone has been employed as the PB reagent throughout these studies, which shows the advantages of good compatibility with ESI as a co-solvent and little interference for MS analysis. Starting with a brief background introduction of the chemistry of the PB reaction, we will discuss the experimental setup for implementing the PB reaction online with ESI-MS, the typical reaction phenomena, MS/MS methods for structural identification and quantitation based on CID of the PB products, using unsaturated standard lipids of fatty acids (FAs), glycerophospholipids (GPs), and cholesteryl esters (CEs) as examples. Applications of PB-MS/MS in shotgun lipid analysis are demonstrated with human plasma, cells, plants and animal tissue samples. The potential of PB-MS/MS in biomedical research is demonstrated by detecting composition changes of lipid C=C location isomers from human prostate cancer cells and mouse breast cancer tissues.Chapter 8. Conventional and Current Methods for the Analysis of Hydroxy Fatty Acids. Nuanyi Liang and Jonathan M. Curtis. Pages 175 - 222 Hydroxy fatty acids (HFAs) are important constituents of cellular structures. They are involved in processes such as the moderation of membrane fluidity, single- or multi-cellular signaling processes and the self-defense of organisms. These bioactivities are often distinct from those of their non-hydroxy metabolic precursors or analogs. Furthermore, their presence is an indicator of the extent of lipid oxidation, metabolic status, disease development and species identification. Due to their low abundance (with a few notable exceptions), and their complexity and susceptibility to isomerize and degrade, HFA profiles can be difficult to determine and quantify. However, such information is critically important to understanding the biological processes in which they participate. This chapter is a summary of the progress that has been made to identify and quantify HFAs. It begins with a description of the biological significance of HFAs, which has stimulated interest in developing novel approaches to the qualitative and quantitative measurement of HFA species and profiles.Chapter 9. Mass Spectrometry of Lipid Vitamins. Jonas Abdel-Khalik. Pages 223 - 262 The deficiency of lipid vitamins is a worldwide issue. Deficiency in these vitamins has been associated with multiple diseases. Thus, there is an increasing interest in the assessment of the status of vitamins A, D, E and K. Usually, serum or plasma levels of one or more vitamin species or metabolites thereof are determined when assessing vitamin status. Lipid vitamins have historically been determined by either immunoassays, or ultraviolet, fluorescence and electrochemical detection. Mass spectrometry combines sensitivity, specificity with structural elucidation and is therefore gaining popularity and becoming the gold standard for analysis of vitamin lipids. This chapter reviews the analysis of lipid vitamins in serum or plasma by liquid chromatography or gas chromatography coupled to mass spectrometry. Sample preparation, the chromatographic setup, ionisation, derivatisation techniques, and common fragments formed during tandem mass spectrometry, are reviewed for each lipid vitamin.Chapter 10. New Scans and Resources in Lipidomics. W. J. Griffiths and Y. Wang. Pages 263 - 282.In the 1970s and 1980s, lipidomics existed but under the guise of “metabolite profiling”, largely performed on gas chromatography – mass spectrometry (GC-MS) instruments or using fast atom bombardment (FAB) ionisation on high-resolution magnetic sector MS instruments. Today, lipidomics has become a field of study in its own right with electrospray as the dominating ionisation mode, i.e. ESI-MS, often linked with online chromatographic separation and tandem mass spectrometry (MS/MS). In this chapter we will discuss some of the newer scan modes available on modern instruments made possible by fast scanning and high-resolution with accurate mass measurement.Grissa, D., Comte, B., Pétéra, M., Pujos-Guillot, E., Napoli, A., 2020. A hybrid and exploratory approach to knowledge discovery in metabolomic data. Discrete Applied Mathematics 273, 103-116. this paper, we propose a hybrid and exploratory knowledge discovery approach for analyzing metabolomic complex data based on a combination of supervised classifiers, pattern mining and Formal Concept Analysis (FCA). The approach is based on three main operations, preprocessing, classification, and postprocessing. Classifiers are applied to datasets of the form individuals × features and produce sets of ranked features which are further analyzed. Pattern mining and FCA are used to provide a complementary analysis and support for visualization. A practical application of this framework is presented in the context of metabolomic data, where two interrelated problems are considered, discrimination and prediction of class membership. The dataset is characterized by a small set of individuals and a large set of features, in which predictive biomarkers of clinical outcomes should be identified. The problems of combining numerical and symbolic data mining methods, as well as discrimination and prediction, are detailed and discussed. Moreover, it appears that visualization based on FCA can be used both for guiding knowledge discovery and for interpretation by domain analysts.Grozeva, N.G., Klein, F., Seewald, J.S., Sylva, S.P., 2020. Chemical and isotopic analyses of hydrocarbon-bearing fluid inclusions in olivine-rich rocks. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20180431. examined the mineralogical, chemical and isotopic compositions of secondary fluid inclusions in olivine-rich rocks from two active serpentinization systems: the Von Damm hydrothermal field (Mid-Cayman Rise) and the Zambales ophiolite (Philippines). Peridotite, troctolite and gabbroic rocks in these systems contain abundant CH4-rich secondary inclusions in olivine, with less abundant inclusions in plagioclase and clinopyroxene. Olivine-hosted secondary inclusions are chiefly composed of CH4 and minor H2, in addition to secondary minerals including serpentine, brucite, magnetite and carbonates. Secondary inclusions in plagioclase are dominated by CH4 with variable amounts of H2 and H2O, while those in clinopyroxene contain only CH4. We determined hydrocarbon abundances and stable carbon isotope compositions by crushing whole rocks and analysing the released volatiles using isotope ratio monitoring—gas chromatography mass spectrometry. Bulk rock gas analyses yielded appreciable quantities of CH4 and C2H6 in samples from Cayman (4–313?nmol?g?1 CH4 and 0.02–0.99?nmol?g?1 C2H6), with lesser amounts in samples from Zambales (2–37?nmol?g?1 CH4 and 0.004–0.082?nmol?g?1 C2H6). Mafic and ultramafic rocks at Cayman exhibit δ13CCH4 values of ?16.7‰ to ?4.4‰ and δ13CC2H6 values of ?20.3‰ to +0.7‰. Ultramafic rocks from Zambales exhibit δ13CCH4 values of ?12.4‰ to ?2.8‰ and δ13CC2H6 values of ?1.2‰ to ?0.9‰. Similarities in the carbon isotopic compositions of CH4 and C2H6 in plutonic rocks, Von Damm hydrothermal fluids, and Zambales gas seeps suggest that leaching of fluid inclusions may provide a significant contribution of abiotic hydrocarbons to deep-sea vent fluids and ophiolite-hosted gas seeps. Isotopic compositions of CH4 and C2H6 from a variety of hydrothermal fields hosted in olivine-rich rocks that are similar to those in Von Damm vent fluids further support the idea that a significant portion of abiotic hydrocarbons in ultramafic-influenced vent fluids is derived from fluid inclusions.Gunsch, M.J., Liu, J., Moffett, C.E., Sheesley, R.J., Wang, N., Zhang, Q., Watson, T.B., Pratt, K.A., 2020. Diesel soot and amine-containing organic sulfate aerosols in an Arctic oil field. Environmental Science & Technology 54, 92-101. rapid decrease in Arctic sea ice is motivating development and increasing oil and gas extraction activities. However, few observations of these local Arctic emissions exist, limiting the understanding of impacts on atmospheric composition and climate. To address this knowledge gap, the chemical composition of atmospheric aerosols was measured within the North Slope of Alaska oil fields during August and September 2016 using an aerosol time-of-flight mass spectrometer (ATOFMS) and a time-of-flight aerosol chemical speciation monitor (ToF-ACSM). Plumes from oil and gas extraction activities were characterized by soot internally mixed with sulfate (matching diesel soot) and organic carbon particles containing aminium sulfate salts. Sea spray aerosol at the coastal site was frequently internally mixed with sulfate and nitrate, from multiphase chemical processing from elevated NOx and SO2 within the oil field. Background (nonplume) air masses were characterized by aged combustion aerosol. No periods of “clean” (nonpolluted) Arctic air were observed. The composition of the nonrefractory aerosol measured with the ACSM was similar during plume and background periods and was consistent with the mass concentrations of nonrefractory particles measured by ATOFMS. Two ultrafine aerosol growth events were observed during oil field background periods and were correlated with fine mode amine-containing particles.Guo, D., Ou, W., Ning, F., Fang, B., Liu, Z., Fang, X., Lu, W., Zhang, L., Ud Din, S., He, Z., 2020. The effects of hydrate formation and dissociation on the water-oil interface: Insight into the stability of an emulsion. Fuel 266, 116980. of the stability of oil-dominated emulsion, such as the oil-based drilling fluids and crude oils, is of great importance to control the gas hydrate risk management when gas hydrates formation and dissociation occurs in the emulsion. Here, a high-pressure optical capillary cell with micro-Raman spectroscopy is utilized to investigate the effects of hydrate formation and dissociation on the stability of a simulated oil-water emulsion and the micro kinetics near the oil/water interface. Both the hydrate formation and dissociation processes are stimulated in water phase near the oil-water interface. The results show that the oil can enter the water phase from the oil phase with the oil-water interface failure when hydrates rapidly growth very close to the water-oil interface, even resulting in a series of oil droplets in the water phase (oil-droplet trajectory). The interesting phenomenon are mainly caused by the concentration gradient of methane and the Marangoni effect. Subsequently, the hydrate phase dissociates, a new stable water-oil interface presents when the system becomes rebalanced. The methane diffusion behavior induced by the chemical potential gradient in hydrate formation and dissociation processes could affect the stability of the emulsion. In addition, a more profound conceptual hydrate-induced destabilization model for different types of oil-water emulsions is proposed. This study can provide a theoretical and experimental basis for the safe implementation for deep-water oil and gas drilling, hydrate drilling in permafrost and multiphase mixing transportation in pipelines.Guo, H., Chen, C., Liang, W., Zhang, Y., Duan, K., Zhang, P., 2020. Enhanced biomethane production from anthracite by application of an electric field. International Journal of Coal Geology 219, 103393. utilization of biogenic coalbed methane (CBM) meets the increasing demand of energy and reduces the impact of greenhouse gases on the environment. Application of an electric field is a promising technology to increase biomethane production from various complex organic compounds. Here, the effects of an applied voltage (0.6 V, 1.2 V, and 1.8 V) on methane production due to coal biodegradation, as well as the structure of microflora and intermediates were studied by anaerobic culture, pyrosequencing, and GC–MS. The maximum methane production was observed at 1.2 V with an average of 63.0 μmol/g of coal, which was 134% higher than the control without electrodes (26.9 μmol/g of coal). The CO2 yield was negatively correlated with the methane yield, suggesting that more carbon in coal has been transferred to methane after application of an electric field. The pyrosequencing results showed that the abundance of bacteria with extracellular electron transfer abilities, such as Soehngenia, Desulfovibrio, and Deferrisoma, increased after applying a 1.2 V electric field. Moreover, the structure of the fungal communities changed significantly, especially the abundance of Mortierella, Thielavia, Humicola, and Plectosphaerella. According to the GC-MS results, most of the products detected at the end of the cultivation period in the control were not detected in the cultures cultivated at 1.2 V. New organic compounds such as alcohols, unsaturated fatty acids, and amines were produced in the cultures cultivated at 1.2 V. These results suggest that application of an electric field changes the structure of the microflora, which promotes extracellular electron transfer and the biodegradation of organic compounds, thus enhancing methane production from coal. Furthermore, the distinct organic products detected after cultivation and the significant changes in microbial communities suggest that the degrading metabolism of organic matter in coal might be altered due to the application of an electric field. Based on the results, a biogenic methane production system implemented by application of an electric field was proposed and described.Guo, Y., Deng, W., Wei, G., Chen, X., Liu, X., Wang, X., Lo, L., Cai, G., Zeng, T., 2020. Exploring the temperature dependence of clumped isotopes in modern Porites corals. Journal of Geophysical Research: Biogeosciences 125, e2019JG005402.: Porites corals are valuable geological archives for reconstructing past sea surface temperature (SST) in tropical oceans. Their clumped isotope compositions (indicated by Δ47 values) provide a potential proxy for SST. The Δ47 value in Porites coral usually departs from thermodynamic equilibrium due to vital effects. To explore the temperature dependence of Δ47 values in corals, we determined δ13C, δ18O, and Δ47 values in two modern Porites corals from the South China Sea. Our results indicate no intercolony or intracolony biases in Δ47 values on annual timescales. However, on seasonal timescales, Δ47 enrichment associated with δ13C depletion is observed at an intracolony level. This cannot be explained by incomplete hydration and/or hydroxylation of metabolic CO2; instead, we interpret this new pattern of isotopic anomalies as a peculiar evidence of vital effects on Δ47 and δ13C fractionation. Although complicated by vital effects, the Δ47 signature in Porites corals still preserved a robust SST dependence, similar to those of recently published Δ47‐T calibrations. The observed Δ47 offset relative to inorganic carbonate due to the vital effects is consistent, and relative variations in seasonal SST can be obtained. This study refines the Δ47 thermometer in Porites corals and strengthens its capacity to be used to reconstruct past SST.Plain Language Summary: Sea surface temperature (SST) is a fundamental parameter of climate variation. Understanding how SST has changed in the past is important to inform climate predictions. One way to do this is by developing a reliable thermometer based on the clumped isotope composition (Δ47) of corals. However, the thermometer based on coral Δ47 values may be complicated by biological factors that affect the Δ47 values as the coral grows. We investigated two modern Porites corals from the South China Sea by measuring their oxygen, carbon, and clumped isotope compositions. By comparing two samples from the same coral colony, we found that the impact of biological factors is significant, causing unusual patterns in the carbon and clumped isotopes. The biological factors also likely lead to differences in the coral Δ47 values from two different colonies. To account for these potential intracolony and intercolony effects, we established a relationship between the Δ47 values and SST based on the two corals. This relationship has the same temperature dependence as other Δ47 thermometers established on synthetic carbonates in which no biological factors are involved and can be used as a thermometer to reconstruct seasonal SST.Guzmán-Trampe, S.M., Ikeda, H., Vinuesa, P., Macías-Rubalcava, M.L., Esquivel, B., Centeno-Leija, S., Tapia-Cabrera, S.M., Mora-Herrera, S.I., Ruiz-Villafán, B., Rodríguez-Sanoja, R., Sanchez, S., 2020. Production of distinct labdane-type diterpenoids using a novel cryptic labdane-like cluster from Streptomyces thermocarboxydus K155. Applied Microbiology and Biotechnology 104, 741-750. mining of the Streptomyces thermocarboxydus K155 genome predicted the presence of four synthases for the production of geosmin, hopene, albaflavenone, and a type B-type A diterpenoid system like that described for labdane-related diterpenoids (LRD). The lrd cluster was comprised by an operon of four genes (lrdABDC). This cluster seemed to be silent in the wild-type strain, as neither labdane nor terpene-like compounds were detected by UPLC-TOF-MS and GC-MS analyses in both culture supernatants and mycelial extracts. Heterologous expression of the lrdABDC cluster in a defective cyslabdan producer (Streptomyces cyslabdanicus K04-0144Δcld) generated 8,17-epoxy-7-hydroxy labda-12,14-diene and cyslabdan. The same cluster expressed in the strains Streptomyces coelicolor M1152, Streptomyces peucetius var. caesius, and Streptomyces avermitilis SUKA22 produced the general intermediary labda-8(17), 12(E),14-triene [(E)-biformene]. Besides (E)-biformene, S. coelicolor M1152 and S. avermitilis SUKA22 produced two and three different labdane-type diterpenoids, underlying the relevance of the genetic background of the Streptomyces host in product formation.Hackbusch, S., Noirungsee, N., Viamonte, J., Sun, X., Bubenheim, P., Kostka, J.E., Müller, R., Liese, A., 2020. Influence of pressure and dispersant on oil biodegradation by a newly isolated Rhodococcus strain from deep-sea sediments of the Gulf of Mexico. Marine Pollution Bulletin 150, 110683. new Rhodococcus strain, capable of degrading crude oil, was isolated from the Gulf of Mexico deep-sea sediment and was investigated for its biodegradation characteristics under atmospheric as well as under deep-sea pressure (1500?m?=?15?MPa). Additionally, the effect of dispersant (Corexit EC9500A) addition was studied. Rhodococcus sp. PC20 was shown to degrade 60.5?±?10.7% of the saturated and aromatic fraction of crude oil at atmospheric pressure and 74.2?±?9.1% at deep-sea level pressure within 96?h. Degradation rates, especially for monoaromatic hydrocarbons, were significantly higher at elevated pressure compared to atmospheric pressure. This study found a growth inhibiting effect at a dispersant to oil ratio of 1:100 and higher. This effect of the dispersant was enhanced when elevated pressure was applied.Hackley, P.C., Araujo, C.V., Borrego, A.G., Bouzinos, A., Cardott, B.J., Carvajal-Ortiz, H., López Cely, M.R., Chabalala, V., Crosdale, P.J., Demchuk, T.D., Eble, C.F., Flores, D., Furmann, A., Gentzis, T., Gon?alves, P.A., Guvad, C., Hámor-Vidó, M., Jelonek, I., Johnston, M.N., Juliao-Lemus, T., Kalaitzidis, S., Knowles, W.R., Kus, J., Li, Z., Macleod, G., Mastalerz, M., Menezes, T.R., Ocubalidet, S., Orban, R., Pickel, W., Ranasinghe, P., Ribeiro, J., Gómez Rojas, O.P., Ruiz-Monroy, R., Schmidt, J.S., Seyedolali, A., Siavalas, G., Suarez-Ruiz, I., Vargas, C.V., Valentine, B.J., Wagner, N., Wrolson, B., Jaramillo Zapata, J.E., 2020. Testing reproducibility of vitrinite and solid bitumen reflectance measurements in North American unconventional source-rock reservoir petroleum systems. Marine and Petroleum Geology 114, 104172. interlaboratory study (ILS) was conducted to test reproducibility of vitrinite and solid bitumen reflectance measurements in six mudrock samples from United States unconventional source-rock reservoir petroleum systems. Samples selected from the Marcellus, Haynesville, Eagle Ford, Barnett, Bakken and Woodford are representative of resource plays currently under exploitation in North America. All samples are from marine depositional environments, are thermally mature (Tmax >445 °C) and have moderate to high organic matter content (2.9–11.6 wt% TOC). Their organic matter is dominated by solid bitumen, which contains intraparticle nano-porosity. Visual evaluation of organic nano-porosity (pore sizes < 100 nm) via SEM suggests that intraparticle organic nano-pores are most abundant in dry gas maturity samples and less abundant at lower wet gas/condensate and peak oil maturities. Samples were distributed to ILS participants in forty laboratories in the Americas, Europe, Africa and Australia; thirty-seven independent sets of results were received. Mean vitrinite reflectance (VRo) values from all ILS participants range from 0.90 to 1.83% whereas mean solid bitumen reflectance (BRo) values range from 0.85 to 2.04% (no outlying values excluded), confirming the thermally mature nature of all six samples. Using multiple statistical approaches to eliminate outlying values, we evaluated reproducibility limit R, the maximum difference between valid mean reflectance results obtained on the same sample by different operators in different laboratories using different instruments. Removal of outlying values where the individual signed multiple of standard deviation was >1.0 produced lowest R values, generally ≤0.5% (absolute reflectance), similar to a prior ILS for similar samples. Other traditional approaches to outlier removal (outside mean ± 1.5*interquartile range and outside F10 to F90 percentile range) also produced similar R values. Standard deviation values < 0.15*(VRo or BRo) reduce R and should be a requirement of dispersed organic matter reflectance analysis. After outlier removal, R values were 0.1%–0.2% for peak oil thermal maturity, about 0.3% for wet gas/condensate maturity and 0.4%–0.5% for dry gas maturity. That is, these R values represent the uncertainty (in absolute reflectance) that users of vitrinite and solid bitumen reflectance data should assign to any one individual reported mean reflectance value from a similar thermal maturity mudrock sample. R values of this magnitude indicate a need for further standardization of reflectance measurement of dispersed organic matter. Furthermore, these R values quantify realistic interlaboratory measurement dispersion for a difficult but critically important analytical technique necessary for thermal maturity determination in the source-rock reservoirs of unconventional petroleum systems.Hakimi, M.H., Al-Matary, A.M., El-Mahdy, O., Hatem, B.A., Kahal, A.Y., Lashin, A., 2020. Organic geochemistry characterization of Late Jurassic bituminous shales and their organofacies and oil generation potential in the Shabwah depression, southeast Sabatayn, Yemen. Journal of Petroleum Science and Engineering 188, 106951. shales of the Late Jurassic Madbi Formation from Shabwah depression in the south-eastern Sabatayn Basin has been collected and analyzed. The organofacies, paleo-sedimentary environmental conditions and oil generation potential are discussed based on combined geochemistry and petrology investigations. Biomarkers indicate that the bituminous-analyzed shales contain mainly marine phytoplankton algae and minor land plants and deposited under reducing environmental conditions. The rich in lipids from phytoplankton algae and land plants suggest high Type II to mixtures of Types II and Type III kerogen as the original organic facies during deposition. This is consistent with significant amounts of alginite and amorphous organic matter, with minor vitrinite land plants observed under microscope and hydrogen index (HI) values of 210–679 mg HC per g TOC and indicated good to excellent oil-source rocks. The presence of the reducing conditions during deposition consequently enhanced the preservation and subsequently gave rise to enrichment of organic matter in the analyzed bituminous shale as indicated by the relatively high TOC values between 1 and 14 wt%.The geochemical maturity indicators show that the analyzed bituminous shales have reached a low maturity stage, and commercial oils have not yet generated. Therefore, the results presented and discussed in this study suggest that the low maturity bituminous shales can be heated to crack the kerogens and subsequently significant amount of oil can be generated. This will lead to a huge alternative potential of unconventional resources and provide a sense of extending the exploration activities for both unconventional and conventional petroleum resources in the whole Basin.Hallmann, C., Nettersheim, B.J., Brocks, J.J., Schwelm, A., Hope, J.M., Not, F., Lomas, M., Schmidt, C., Schiebel, R., Nowack, E.C.M., De Deckker, P., Pawlowski, J., Bowser, S.S., Bobrovskiy, I., Zonneveld, K., Kucera, M., Stuhr, M., 2020. Reply to: Sources of C30 steroid biomarkers in Neoproterozoic–Cambrian rocks and oils. Nature Ecology & Evolution 4, 37-39. Article: Nettersheim, B.J., Brocks, J.J., Schwelm, A., Hope, J.M., Not, F., Lomas, M., Schmidt, C., Schiebel, R., Nowack, E.C.M., De Deckker, P., Pawlowski, J., Bowser, S.S., Bobrovskiy, I., Zonneveld, K., Kucera, M., Stuhr, M., Hallmann, C., 2019. Putative sponge biomarkers in unicellular Rhizaria question an early rise of animals. Nature Ecology & Evolution 3, 577-mented on by: Love, G.D., Zumberge, J.A., Cárdenas, P., Sperling, E.A., Rohrssen, M., Grosjean, E., Grotzinger, J.P., Summons, R.E., 2020. Sources of C30 steroid biomarkers in Neoproterozoic–Cambrian rocks and oils. Nature Ecology & Evolution 4, 34-36.Halloran, P.R., Hall, I.R., Menary, M., Reynolds, D.J., Scourse, J.D., Screen, J.A., Bozzo, A., Dunstone, N., Phipps, S., Schurer, A.P., Sueyoshi, T., Zhou, T., Garry, F., 2020. Natural drivers of multidecadal Arctic sea ice variability over the last millennium. Scientific Reports 10, 688. climate varies due to human activity, natural climate cycles, and natural events external to the climate system. Understanding the different roles played by these drivers of variability is fundamental to predicting near-term climate change and changing extremes, and to attributing observed change to anthropogenic or natural factors. Natural drivers such as large explosive volcanic eruptions or multidecadal cycles in ocean circulation occur infrequently and are therefore poorly represented within the observational record. Here we turn to the first high-latitude annually-resolved and absolutely dated marine record spanning the last millennium, and the Paleoclimate Modelling Intercomparison Project (PMIP) Phase 3 Last Millennium climate model ensemble spanning the same time period, to examine the influence of natural climate drivers on Arctic sea ice. We show that bivalve oxygen isotope data are recording multidecadal Arctic sea ice variability and through the climate model ensemble demonstrate that external natural drivers explain up to third of this variability. Natural external forcing causes changes in sea-ice mediated export of freshwater into areas of active deep convection, affecting the strength of the Atlantic Meridional Overturning Circulation (AMOC) and thereby northward heat transport to the Arctic. This in turn leads to sustained anomalies in sea ice extent. The models capture these positive feedbacks, giving us improved confidence in their ability to simulate future sea ice in in a rapidly evolving Arctic.Hamby, H., Li, B., Shinopoulos, K.E., Keller, H.R., Elliott, S.J., Dukovic, G., 2020. Light-driven carbon?carbon bond formation via CO2 reduction catalyzed by complexes of CdS nanorods and a 2-oxoacid oxidoreductase. Proceedings of the National Academy of Sciences 117, 135-140.: Nature uses enzymes to catalyze a vast array of complex chemical reactions. Enzymes that catalyze reduction reactions require partners that provide the electrons ultimately used in catalysis. In nature, the associated electron transfer sequences can be complicated, energy-inefficient, and rate determining. Here, we employ artificial electron donors, photoexcited semiconductor nanocrystals, to provide the electrons for catalysis. We couple these nanocrystals with an enzyme that catalyzes the formation of carbon?carbon bonds via CO2 reduction. With this architecture, we demonstrate light-driven formation of 2-oxoglutarate, storing some of the photon energy in the chemical product. We examine the role of electron transfer from the nanocrystal to the enzyme in the light-driven chemical conversion and learn that the enzyme modulates this process during catalysis.Abstract: Redox enzymes are capable of catalyzing a vast array of useful reactions, but they require redox partners that donate or accept electrons. Semiconductor nanocrystals provide a mechanism to convert absorbed photon energy into redox equivalents for enzyme catalysis. Here, we describe a system for photochemical carbon?carbon bond formation to make 2-oxoglutarate by coupling CO2 with a succinyl group. Photoexcited electrons from cadmium sulfide nanorods (CdS NRs) transfer to 2-oxoglutarate:ferredoxin oxidoreductase from Magnetococcus marinus MC-1 (MmOGOR), which catalyzes a carbon?carbon bond formation reaction. We thereby decouple MmOGOR from its native role in the reductive tricarboxylic acid cycle and drive it directly with light. We examine the dependence of 2-oxoglutarate formation on a variety of factors and, using ultrafast transient absorption spectroscopy, elucidate the critical role of electron transfer (ET) from CdS NRs to MmOGOR. We find that the efficiency of this ET depends strongly on whether the succinyl CoA (SCoA) cosubstrate is bound at the MmOGOR active site. We hypothesize that the conformational changes due to SCoA binding impact the CdS NR?MmOGOR interaction in a manner that decreases ET efficiency compared to the enzyme with no cosubstrate bound. Our work reveals structural considerations for the nano?bio interfaces involved in light-driven enzyme catalysis and points to the competing factors of enzyme catalysis and ET efficiency that may arise when complex enzyme reactions are driven by artificial light absorbers.Hampton, H.G., Watson, B.N.J., Fineran, P.C., 2020. The arms race between bacteria and their phage foes. Nature 577, 327-336. are under immense evolutionary pressure from their viral invaders—bacteriophages. Bacteria have evolved numerous immune mechanisms, both innate and adaptive, to cope with this pressure. The discovery and exploitation of CRISPR–Cas systems have stimulated a resurgence in the identification and characterization of anti-phage mechanisms. Bacteriophages use an extensive battery of counter-defence strategies to co-exist in the presence of these diverse phage defence mechanisms. Understanding the dynamics of the interactions between these microorganisms has implications for phage-based therapies, microbial ecology and evolution, and the development of new biotechnological tools. Here we review the spectrum of anti-phage systems and highlight their evasion by bacteriophages.Han, H., Pang, P., Zhong, N., Luo, Q., Ma, Y., Gao, Y., 2020. The pore characteristics and gas potential of the Jurassic continental shales in the middle-small basins, northwest China. Journal of Petroleum Science and Engineering 188, 106873. continental shales were extensively developed in the northwest of China. To characterize and analyze the pores and gas potential of these shales, geochemical, mineralogical, petrophysical, and methane adsorption capacity (MAC) experiments were performed on 10 samples. The results indicated that these shales have a high total organic carbon (TOC) content, low porosity and permeability. Interparticle pores between clay platelets are dominant. Organic matter (OM) pores cannot be observed using scanning electron microscope. The methane adsorption capacity is strong, and it is controlled by TOC content. Strong MAC indicated the shales have an excellent capacity of storing gas. In addition, type III organic matters can generate amount of gas at a lowly mature stage. Therefore, it is speculated that the studied shales have a good gas potential, which is supported by canister desorption results.Han, R., Lv, J., Huang, Z., Zhang, S., Zhang, S., 2019. Pathway for the production of hydroxyl radicals during the microbially mediated redox transformation of iron (oxyhydr)oxides. Environmental Science & Technology 54, 902-910. reduction of ferric iron (Fe(III)) to ferrous iron (Fe(II)) by dissimilatory iron-reducing bacteria is widespread in anaerobic environments. The oxidation of Fe(II) in aerobic environments has been found to produce hydroxyl radicals (?OH); however, the role of iron-reducing bacteria in the process has not been well understood. Here, Shewanella oneidensis MR-1-mediated redox transformation of four typical iron (oxyhydr)oxides and the production of reactive oxygen species were investigated. The results showed that the production of ?OH was mainly determined by the insoluble Fe(II) formed during microbially mediated reduction and also mediated by the mineralogical phase. Moreover, this study for the first time observed the exogenetic iron-independent production of ?OH by S. oneidensis MR-1, and the integrated pathway of ?OH generation during the iron redox process was revealed. Superoxide (O2?–) was indicated as a key intermediate species that was produced by both abiotic and biotic pathways, and ?OH was generated by both the exogenetic iron-dependent Fenton-like reaction and exogenetic iron-independent pathways. S. oneidensis MR-1 played a pivotal role in both the reduction of Fe(III) and the production of O2?–. These findings contribute substantially to our understanding of the generation mechanism of reactive oxygen species at oxidation–reduction boundaries in the environment.Han, Y., Poetz, S., Mahlstedt, N., Horsfield, B., 2020. On the release of acidic NSO compounds from the oil-mature Barnett Shale using different solvents. Journal of Petroleum Science and Engineering 185, 106605. transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) is continuing to provide new and important insights into the composition of nitrogen-, sulfur-, and oxygen-containing (NSO) compounds of shale extracts, but its analytical window is principally determined by the polarity of the solvent used for extraction. Here we compare the selectivity with which DM (dichloromethane: methanol, v/v?=?99:1) and an azeotropic solvent mixture ACM (acetone: chloroform: methanol, v/v/v?=?38: 32: 30) release NSO-compounds from the oil-mature Barnett Shale of the Fort Worth Basin (USA). DM extracted less polar and smaller NSO compounds in comparison with ACM, in line with its relatively low polarity. N1, N1O1 and O2 compounds are the dominating species in the DM extracts, whereas the likely more polar compounds such as the N2, N1O2 and N2O1 species are almost un-extracted using DM. Even for the N1, N1O1 and O2 species, their high DBE (double bond equivalent) classes were neither efficiently extracted using DM. Because NSO compounds are fractionated during both primary and secondary migration, and geochemical indices have been developed to address the magnitude of these processes, it is vital that relevant chemical species are recovered from the shale efficiently. The inefficient extraction of DM makes the previous investigations of NSO compounds apparently doubtful. ACM has proved to be by far a better solvent, not only because of its high polarity but also because it is likely to gain access to the components trapped in kerogen by bringing about swelling. The azeotropic solvent mixture ACM is recommended for extracting oil-mature shale for future FT-ICR-MS analysis.Hand, E., 2020. Cheap shots. Science 367, 354-358. reveals exquisite molecular structures—at high cost. A cheaper microscope could bring the resolution revolution to the masses.Hansen, F.A., Pedersen-Bjergaard, S., 2020. Emerging extraction strategies in analytical chemistry. Analytical Chemistry 92, 2-15. in the context of analytical chemistry (analytical-scale extraction) is defined as “the transfer of target analyte from one phase to a different phase where further processing and analysis occurs”.(1) The target analyte is thus isolated from the original sample, and transferred into an extract. In this way, the target analyte is separated from major sample matrix components. The sample is often a liquid, and the target analyte is extracted into (a) another liquid or (b) onto a solid. Extraction according to (a) and (b) are termed liquid–liquid extraction (LLE) and solid-phase extraction (SPE), respectively, and involve partition and mass transfer across liquid–liquid and liquid–solid boundaries. Partition is based on intermolecular forces involving hydrophobic, dispersion, dipole, hydrogen bond, and ionic interactions. The molecular interactions are highly influenced by the chemical properties of the extraction phase (extraction chemistry). In this review, we discuss new extraction phases, which are currently investigated in the scientific literature. In addition, we discuss new technical formats (geometries) for extraction. Emerging extraction strategies, as stated in the review title, are thus defined as new extraction phases and new technical formats in this review. Measurements in analytical chemistry are performed with analytical instruments based on chromatography, electrophoresis, spectroscopy/spectrometry, and electrochemistry. Prior to such measurements, sample preparation is required, and this typically involves extraction. Extraction improves the compatibility of the sample with the analytical instrument. Extraction also cleans up samples and reduces interferences and contamination of the analytical instrument. Finally, extraction may preconcentrate the analyte to lower the limit of detection/quantification. While development of analytical instruments has been a very active field of research for decades, sample preparation and analytical-scale extraction is less developed. Even today, sample preparation is often performed with old LLE and SPE procedures. Fortunately, research on new extraction strategies has increased during the last 2 decades. Solid-phase microextraction (SPME),(2) stir bar sorptive extraction (SBSE),(3) and microextraction by packed sorbent (MEPS)(4) are examples of new techniques derived from this research. They are different miniaturized formats for solid-phase extraction and are commercially available. Thus, SPME, SBSE, and MEPS equipment is standardized and produced industrially, and the techniques are gradually being implemented into routine applications. In parallel to this, new extraction strategies are under development. Largely, this research is conducted in university laboratories, and the scientific papers are focused on proof-of-principle experiments. A Scopus search on “extraction” and “chromatography” provides more than 122?000 research papers, and a similar search on “extraction” and “spectrometry” identifies about 76?000 documents. Among all these papers, about 8?000 were published in 2019. Providing a balanced overview and identifying all major trends among these papers is “mission impossible”. Therefore, in this annual review we have made a selection and focused on new (a) liquid and (b) solid extraction phases and (c) on microextraction systems. Research on (a) and (b) is basically about intermolecular interactions and chemistry. This is of general interest and can be used in many different applications and technical configurations. Research on (c) is about technical configurations and applicability of miniaturized extraction systems, which is a major trend in the field. The purpose is to give a flavor of the research, mainly based on research papers published in 2019. We discuss the principles and the trends, and we highlight selected papers from 2019. For readers interested in more details, dedicated reviews for further reading are provided. The scientific activity level within (a), (b), and (c) has been indicated by the number of papers found in Scopus. These numbers are definitely not exact and are intended as rough estimates only. The selection of highlighted papers was supported by Scopus 2019 citation frequency.Haram, L.E., Carlton, J.T., Ruiz, G.M., Maximenko, N.A., 2020. A Plasticene Lexicon. Marine Pollution Bulletin 150, 110714. plastic pollution in the environment has increased rapidly in the last half century, so too has the study of the effects of plastic on marine, aquatic and terrestrial ecosystems. From this research, a series of new terms has emerged to describe the phenomena unique to the presence of plastic-based materials in nature. In this short note, we bring together disparate neologisms into a single lexicon with the aim to encourage use of a unified vocabulary to describe the new reality of ecological, chemical, and geological systems in the age of plastics.Harper, D.A.T., Cascales-Mi?ana, B., Servais, T., 2020. Early Palaeozoic diversifications and extinctions in the marine biosphere: a continuum of change. Geological Magazine 157, 5-21. review of biodiversity curves of marine organisms indicates that, despite fluctuations in amplitude (some large), a large-scale, long-term radiation of life took place during the early Palaeozoic Era; it was aggregated by a succession of more discrete and regionalized radiations across geographies and within phylogenies. This major biodiversification within the marine biosphere started during late Precambrian time and was only finally interrupted in the Devonian Period. It includes both the Cambrian Explosion and the Great Ordovician Biodiversification Event. The establishment of modern marine ecosystems took place during a continuous chronology of the successive establishment of organisms and their ecological communities, developed during the ‘Cambrian substrate revolution’, the ‘Ordovician plankton revolution’, the ‘Ordovician substrate revolution’, the ‘Ordovician bioerosion revolution’ and the ‘Devonian nekton revolution’. At smaller scales, different regional but important radiations can be recognized geographically and some of them have been identified and named (e.g. those associated with the ‘Richmondian Invasion’ during Late Ordovician time in Laurentia and the contemporaneous ‘Boda event’ in parts of Europe and North Africa), in particular from areas that were in or moved towards lower latitudes, allowing high levels of speciation on epicontintental seas during these intervals. The datasets remain incomplete for many other geographical areas, but also for particular time intervals (e.g. during the late Cambrian ‘Furongian Gap’). The early Palaeozoic biodiversification therefore appears to be a long-term process, modulated by bursts in significant diversity and intervals of inadequate data, where its progressive character will become increasingly clearer with the availability of more complete datasets, with better global coverage and more advanced analytical techniques.Hashemi-Nasab, F.S., Parastar, H., 2020. Pattern recognition analysis of gas chromatographic and infrared spectroscopic fingerprints of crude oil for source identification. Microchemical Journal 153, 104326. this study, a chemometric strategy was developed for analysis of gas chromatographic (GC) and infrared spectroscopic (FT-IR) fingerprints of nine crude oil samples from the main oil wells of Iran to classify them and to find their origins. In this regard, a fractionation method based on saturated, aromatic, resin, and asphaltene (SARA) test was used. Then, these fractions were analyzed by GC-FID and GC-MS. Also, nine crude oil samples were analyzed by FT-IR.The obtained GC fingerprints were aligned using correlation optimized warping (COW) and auto-scaled, and then analyzed using principal component analysis (PCA) and hierarchical cluster analysis (HCA). Evaluation of PCA scores plot (explaining 89.35% of variance for two PCs) and HCA dendrogram showed that aromatic fractions belong to three classes. The clustering results of aliphatic and resin fractions also showed the presence of three clusters but with different samples due to the difference in their composition. The results of unsupervised classification were then used as a starting point for partial least squares-discriminant analysis (PLS-DA) and counter propagation-artificial neural network (CP-ANN).On the other side, FTIR fingerprints of crude oil samples were also clustered using PCA and HCA. Evaluation of PCA scores plot (explaining 95.15% of variance for two PCs) and HCA dendrogram showed that samples belong to three clusters. These initial results were used as a starting point for PLS-DA and CP-ANN. Accuracy of PLS-DA was 0.890 for calibration and 0.818 for test sets. Also, CP-ANN accuracy values were 1.000 and 0.818 for train and test sets, respectively.Heard, A.W., Kite, E.S., 2020. A probabilistic case for a large missing carbon sink on Mars after 3.5 billion years ago. Earth and Planetary Science Letters 531, 116001. has a thin (6 mbar) CO2 atmosphere currently. There is strong evidence for paleolakes and rivers formed by warm climates on Mars, including after 3.5 billion years (Ga) ago, which indicates that a CO2 atmosphere thick enough to permit a warm climate was present at these times. Since Mars no longer has a thick CO2 atmosphere, it must have been lost. One possibility is that Martian CO2 was lost to space. Oxygen escape rates from Mars are high enough to account for loss of a thick CO2 atmosphere, if CO2 was the main source of escaping O. But here, using H isotope ratios, O escape calculations, and quantification of the surface O sinks on Mars, we show for the first time that O escape from Mars after 3.5 Ga must have been predominantly associated with the loss of H2O, not CO2, and therefore it is unlikely that ≥250 mbar Martian CO2 has been lost to space in the last 3.5 Ga, because such results require highly unfavored O loss scenarios. It is possible that the presence of young rivers and lakes on Mars could be reconciled with limited CO2 loss to space if crater chronologies on Mars are sufficiently incorrect that all apparently young rivers and lakes are actually older than 3.5 Ga, or if climate solutions exist for sustained runoff on Mars with atmospheric CO2 pressure <250 mbar. However, our preferred solution to reconcile the presence of <3.5 Gya rivers and lakes on Mars with the limited potential for CO2 loss to space is a large, as yet undiscovered, geological C sink on Mars.Heck, P.R., Greer, J., K??p, L., Trappitsch, R., Gyngard, F., Busemann, H., Maden, C., ?vila, J.N., Davis, A.M., Wieler, R., 2020. Lifetimes of interstellar dust from cosmic ray exposure ages of presolar silicon carbide. Proceedings of the National Academy of Sciences 117, 1884.: Dating of interstellar dust directly with astronomical methods is not possible. Neither is dating based on the decay of long-lived radioactive nuclides, due to current analytical limitations and unknown initial isotopic compositions. Here we present interstellar ages of individual presolar SiC grains from a meteorite. The ages are based on Ne isotopes produced by galactic cosmic rays. Lifetimes of ～60% of our grains are <3 × 108 y, while at least 8% are >109 y, in line with what is expected for large grains. The former could be the end products of stars originating in an enhanced star formation episode. Presolar grains are the oldest datable solid samples available and provide invaluable insight into the presolar chronology of our galaxy.Abstract: We determined interstellar cosmic ray exposure ages of 40 large presolar silicon carbide grains extracted from the Murchison CM2 meteorite. Our ages, based on cosmogenic Ne-21, range from 3.9 ± 1.6 Ma to ～3 ± 2 Ga before the start of the Solar System ～4.6 Ga ago. A majority of the grains have interstellar lifetimes of <300 Ma, which is shorter than theoretical estimates for large grains. These grains condensed in outflows of asymptotic giant branch stars <4.9 Ga ago that possibly formed during an episode of enhanced star formation ～7 Ga ago. A minority of the grains have ages >1 Ga. Longer lifetimes are expected for large grains. We determined that at least 12 of the analyzed grains were parts of aggregates in the interstellar medium: The large difference in nuclear recoil loss of cosmic ray spallation products 3He and 21Ne enabled us to estimate that the irradiated objects in the interstellar medium were up to 30 times larger than the analyzed grains. Furthermore, we estimate that the majority of the grains acquired the bulk of their cosmogenic nuclides in the interstellar medium and not by exposure to an enhanced particle flux of the early active sun.Herber, J., Klotz, F., Frommeyer, B., Weis, S., Straile, D., Kolar, A., Sikorski, J., Egert, M., Dannenmann, M., Pester, M., 2020. A single Thaumarchaeon drives nitrification in deep oligotrophic Lake Constance. Environmental Microbiology 22, 212-228. released during organic matter mineralization is converted during nitrification to nitrate. We followed spatiotemporal dynamics of the nitrifying microbial community in deep oligotrophic Lake Constance. Depth‐dependent decrease of total ammonium (0.01–0.84?μM) indicated the hypolimnion as the major place of nitrification with 15N‐isotope dilution measurements indicating a threefold daily turnover of hypolimnetic total ammonium. This was mirrored by a strong increase of ammonia‐oxidizing Thaumarchaeota towards the hypolimnion (13%–21% of bacterioplankton) throughout spring to autumn as revealed by amplicon sequencing and quantitative polymerase chain reaction. Ammonia‐oxidizing bacteria were typically two orders of magnitude less abundant and completely ammonia‐oxidizing (comammox) bacteria were not detected. Both, 16S rRNA gene and amoA (encoding ammonia monooxygenase subunit B) analyses identified only one major species‐level operational taxonomic unit (OTU) of Thaumarchaeota (99% of all ammonia oxidizers in the hypolimnion), which was affiliated to Nitrosopumilus spp. The relative abundance distribution of the single Thaumarchaeon strongly correlated to an equally abundant Chloroflexi clade CL500‐11 OTU and a Nitrospira OTU that was one order of magnitude less abundant. The latter dominated among recognized nitrite oxidizers. This extremely low diversity of nitrifiers shows how vulnerable the ecosystem process of nitrification may be in Lake Constance as Central Europe's third largest lake.Hiatt, E.E., Pufahl, P.K., Guimar?es da Silva, L., 2020. Iron and phosphorus biochemical systems and the Cryogenian-Ediacaran transition, Jacadigo basin, Brazil: Implications for the Neoproterozoic oxygenation event. Precambrian Research 337, 105533. of the Marinoan Snowball Earth ice age (635 Ma) marked the transition to a greenhouse world. This climate change forever modified the biogeochemical cycling of iron and phosphorus, ended large-scale iron formation deposition, began accumulation of phosphorus on marine shelves, and led to the Ediacaran radiation of eukaryotes. The Jacadigo Basin, Brazil, contains a nearly complete record of this critical transition.Glaciomarine diamictites and iron formation accumulated during two Marinoan ice advances with hydrothermal input of iron delivered via ice-margin upwelling. Biochemically precipitated rhythmites of siderite, sedimentary apatite, and hematite represent microbially mediated, sub-sea ice precipitation. Siderite laminae preserve microbial textures and have a mean ?13C = ?8.80‰, PDB (+/?0.86‰) reflecting degradation of organic matter at the seafloor. These millimeter-scale rhythmites are a sensitive record of sub-ice dynamics because they formed in response to short-term fluctuations of O2 due to seasonal sub-ice photosynthesis. They demonstrate the connection between ice cover, O2, and cycling of iron and nutrient elements such as phosphorus.These biochemical rhythmites suggest that Cryogenian sea ice limited oxygen production prior to the onset of the Neoproterozoic Oxygenation Event. O2 increased enough to concentrate bioavailable phosphorus at the seafloor, which was essential for later diversification of metazoans in the Ediacaran. Such sub-ice Cryogenian biochemical systems may provide Earth-based analogs for life on ice-covered worlds, such as Europa and Enceladus.Hickman-Lewis, K., Foucher, F., Pelletier, S., Messori, F., Westall, F., 2020. Geological appraisals of core samples using the ExoMars 2020 rover instrumentation. Planetary and Space Science 180, 104743. ExoMars 2020 mission will characterise a Martian locality with potential former habitability – Oxia Planum – and attempt to identify preserved morphological and chemical biosignatures. The payload will include a drill retrieving cores from the subsurface (up to 2?m depth), which will be imaged at high resolution by two instruments: the Panoramic Camera High Resolution Camera (PanCam HRC) and CLose UP Imager (CLUPI). These instruments will provide guiding interpretation and govern the approach used by the analytical instruments, which will conduct their analyses after crushing of the core sample. Blind tests using Mars-analogue lithological samples provide valuable mission training in terms of maximising scientific return. Previous blind tests evaluating the abilities of the ExoMars 2020 payload to conduct geological approaches used solid rock hand samples as test specimens. Here, we prepared test samples of ExoMars mission-equivalent shapes and dimensions (3?×?1?cm cores) to evaluate the extent of geological interpretation possible using only the images of the core that will obtained during the mission. In the worst-case scenario, core samples will be different from outcrop rock and these images and associated organogeochemical analyses on crushed powders by the other rover instruments will be the sole basis for their interpretation. Imaging these samples using mission-equivalent original resolutions to avoid image processing artefacts, we found that the difficulty inherent in making definitive geological conclusions using traditional ‘field petrography’ approaches is increased when only limited amounts of core sample are available for observation. Challenges involved in the interpretation of core samples include representativeness problems inherent to small samples, distinction between layer-specific characteristics at the sub-centimetre to centimetre scale, and mechanical effects, such as drill marks and dust covering. These issues vary depending upon the rock type and change as a function of the mechanical properties (and thus composition) of the sample. Despite these challenges, we find that CLUPI and PanCam HRC images alone allow many accurate and detailed geological observations; however, confidence and detail of interpretation are notably increased when additional geochemical data are provided, in this case, Raman spectra reflecting the contribution of the Raman Laser Spectrometer (RLS) instrument. Our results argue for the importance of detailed core imaging during the experimental phase of the rover mission despite the challenges involved in interpretation, since HRC and CLUPI images offer a degree of synergy. Inter-instrumental collaboration will be essential during the ExoMars 2020 rover mission (and indeed in any rover mission), since no single payload instrument is able to perform a comprehensive assessment of a putative biosignature within its geological context, and since the instrument suite provides highly complementary data at multiple scales that are key to maximising scientific return.Hidalgo, K.J., Teramoto, E.H., Soriano, A.U., Valoni, E., Baessa, M.P., Richnow, H.H., Vogt, C., Chang, H.K., Valéria, M.O., 2020. Taxonomic and functional diversity of the microbiome in a jet fuel contaminated site as revealed by combined application of in situ microcosms with metagenomic analysis. Science of The Total Environment 708, 135152. attenuation represents all processes that govern contaminant mass removal, which mainly occurs via microbial degradation in the environment. Although this process is intrinsic its rate and efficiency depend on multiple factors. This study aimed to characterize the microbial taxonomic and functional diversity in different aquifer sediments collected in the saturated zone and in situ microcosms (BACTRAP?s) amended with hydrocarbons (13C-labeled and non-labeled benzene, toluene and naphthalene) using 16S rRNA gene and “shotgun” Illumina high throughput sequencing at a jet-fuel contaminated site. The BACTRAP?s were installed to assess hydrocarbon metabolism by native bacteria. Results indicated that Proteobacteria, Actinobacteria and Firmicutes were the most dominant phyla (~98%) in the aquifer sediment samples. Meanwhile, in the benzene- and toluene-amended BACTRAP?s the phyla Firmicutes and Proteobacteria accounted for about 90% of total community. In the naphthalene-amended BACTRAP?, members of the SR-FBR-L83 family (Order Ignavibacteriales) accounted for almost 80% of bacterial community. Functional annotation of metagenomes showed that only the sediment sample located at the source zone border and with the lowest BTEX concentration, has metabolic potential to degrade hydrocarbons aerobically. On the other hand, in situ BACTRAP?s allowed enrichment of hydrocarbon-degrading bacteria. Metagenomic data suggest that fumarate addition is the main mechanism for hydrocarbon activation of toluene. Also, indications for methylation, hydroxylation and carboxylation as activation mechanisms for benzene anaerobic conversion were found. After 120 days of exposure in the contaminated groundwater, the isotopic analysis of fatty acids extracted from BACTRAP?s demonstrated the assimilation of isotopic labeled compounds in the cells of microbes expressed by strong isotopic enrichment. We propose that the microbiota in this jet-fuel contaminated site has metabolic potential to degrade benzene and toluene by a syntrophic process, between members of the families Geobacteraceae and Peptococcaceae (genus Pelotomaculum), coupled to nitrate, iron and/or sulfate reduction.Hindshaw, R.S., Tosca, R., Tosca, N.J., Tipper, E.T., 2020. Experimental constraints on Mg isotope fractionation during clay formation: Implications for the global biogeochemical cycle of Mg. Earth and Planetary Science Letters 531, 115980. direction and magnitude of magnesium (Mg) isotope fractionation attendant to the formation of clay minerals is fundamental to the use of Mg isotopes to decipher the biogeochemical cycling of Mg in the critical zone and for the oceanic Mg budget. This study provides experimental data on the Mg fractionation factor for two smectite-group minerals (stevensite and saponite) at temperatures relevant for Earth surface processes. The resultant solids were characterised by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR) to confirm the mineralogy and crystallinity of the product. A series of experiments were performed to asses the impact of temperature and pH on isotope fractionation. Bulk solid samples were treated with ammonium chloride to remove exchangeable Mg in order to distinguish the Mg isotopic fractionation between these sites and octahedral sites.All bulk and residual solids were enriched in 24Mg compared to the initial solution and δ26Mg values of the exchangeable pool were lower than, or within error of, the initial solution. Final solutions were either within error of, or enriched in, 26Mg compared to the initial solution, depending on the fraction of Mg removed from solution (fMg). For experiments with small or negligible fMg, increasing the pH resulted in a higher reaction rate and reduced fractionation from the initial solution. This could point to a kinetic effect, but the composition of the residual solid (Mg/(Li+Mg) ratio) was also dependent on pH. The change in the composition was reflected in the wavenumber of the Mg3-OH stretch in FT-IR data, which is a proxy for bond strength, and suggests an equilibrium control. An equilibrium control is further supported by the observation of reduced fractionation compared to the initial solution with increasing temperature. Rayleigh and batch fractionation models were fitted to the data giving fractionation factors of 0.9991 and 0.9990 respectively.We compare our results with existing field and experimental data and suggest that the apparent contradictions surrounding the direction of Mg isotope fractionation into phyllosilicate minerals could be due to the similarity of Mg bond lengths between clay octahedral sites and dissolved Mg. Thus small changes in mineral structure or initial solution conditions may result in a change in bond length sufficient to alter the direction of fractionation, implying that the magnitude and direction of Mg isotope fractionation into clay minerals could be dependent on local field conditions. Alternatively, if the precipitation of secondary clay minerals in the field preferentially incorporates light Mg, as observed in this experimental study, this implies the contribution of carbonate weathering to dissolved Mg fluxes has been underestimated, with major implications for the global biogeochemical cycle of Mg.Hoffmann, R., Bestwick, J., Berndt, G., Berndt, R., Fuchs, D., Klug, C., 2020. Pterosaurs ate soft-bodied cephalopods (Coleoidea). Scientific Reports 10, 1230. evidence of successful or failed predation is rare in the fossil record but essential for reconstructing extinct food webs. Here, we report the first evidence of a failed predation attempt by a pterosaur on a soft-bodied coleoid cephalopod. A perfectly preserved, fully grown soft-tissue specimen of the octobrachian coleoid Plesioteuthis subovata is associated with a tooth of the pterosaur Rhamphorhynchus muensteri from the Late Jurassic Solnhofen Archipelago. Examination under ultraviolet light reveals the pterosaur tooth is embedded in the now phosphatised cephalopod soft tissue, which makes a chance association highly improbable. According to its morphology, the tooth likely originates from the anterior to middle region of the upper or lower jaw of a large, osteologically mature individual. We propose the tooth became associated with the coleoid when the pterosaur attacked Plesioteuthis at or near the water surface. Thus, Rhamphorhynchus apparently fed on aquatic animals by grabbing prey whilst flying directly above, or floating upon (less likely), the water surface. It remains unclear whether the Plesioteuthis died from the pterosaur attack or survived for some time with the broken tooth lodged in its mantle. Sinking into oxygen depleted waters explains the exceptional soft tissue preservation.Hohrenk, L.L., Itzel, F., Baetz, N., Tuerk, J., Vosough, M., Schmidt, T.C., 2020. Comparison of software tools for liquid chromatography–high-resolution mass spectrometry data processing in nontarget screening of environmental samples. Analytical Chemistry 92, 1898-1907. field of high-resolution mass spectrometry has undergone a rapid progress in the last years due to instrumental improvements leading to a higher sensitivity and selectivity of instruments. A variety of qualitative screening approaches, summarized as nontarget screening, have been introduced and have successfully extended the environmental monitoring of organic micropollutants. Several automated data processing workflows have been developed to handle the immense amount of data that are recorded in short time frames by these methods. Most data processing workflows include similar steps, but underlying algorithms and implementation of different processing steps vary. In this study the consistency of data processing with different software tools was investigated. For this purpose, the same raw data files were processed with the software packages MZmine2, enviMass, Compound Discoverer, and XCMS online and resulting feature lists were compared. Results show a low coherence between different processing tools, as overlap of features between all four programs was around 10%, and for each software between 40% and 55% of features did not match with any other program. The implementation of replicate and blank filter was identified as one of the sources of observed divergences. However, there is a need for a better understanding and user instructions on the influence of different algorithms and settings on feature extraction and following filtering steps. In future studies it would be of interest to investigate how final data interpretation is influenced by different processing software. With this work we want to encourage more awareness on data processing as a crucial step in the workflow of nontarget screening.Holakooei, P., Karimy, A.-H., Saeidi-Anaraki, F., Vaccaro, C., Sabatini, F., Degano, I., Colombini, M.P., 2020. Colourants on the wall paintings of a medi?val fortress at the mount Sofeh in Isfahan, central Iran. Journal of Archaeological Science: Reports 29, 102065. on the twelfth century wall paintings excavated at the fortress located on the mount Sofeh in Isfahan, central Iran, were analysed using micro X-ray fluorescence (?-XRF), micro Raman spectroscopy (?-Raman) and high-performance liquid chromatography coupled to electrospray ionization quadropole time-of-flight (HPLC-ESI-Q-TOF). The results of the analyses showed that gypsum, atacamite, carbon black, orpiment and ultramarine blue were used as white, green, black, yellow and blue pigments, respectively. Moreover, three red colourants including red lead, red vermilion and madder red were identified in the wall paintings. Furthermore, possible sources for the colourants are discussed.Holert, J., Brown, K., Hashimi, A., Eltis, L.D., Mohn, W.W., 2020. Steryl ester formation and accumulation in steroid-degrading bacteria. Applied and Environmental Microbiology 86, e02353-19.: Steryl esters (SEs) are important storage compounds in many eukaryotes and are often prominent components of intracellular lipid droplets. Here, we demonstrate that selected Actino- and Proteobacteria growing on sterols are also able to synthesize SEs and to sequester them in cytoplasmic lipid droplets. We found cholesteryl ester (CE) formation in members of the actinobacterial genera Rhodococcus, Mycobacterium, and Amycolatopsis, as well as several members of the proteobacterial Cellvibrionales order. CEs maximally accumulated under nitrogen-limiting conditions, suggesting that steryl ester formation plays a crucial role for storing excess energy and carbon under adverse conditions. Rhodococcus jostii RHA1 was able to synthesize phytosteryl and cholesteryl esters, the latter reaching up to 7% of its cellular dry weight and 69% of its lipid droplets. Purified lipid droplets from RHA1 contained CEs, free cholesterol, and triacylglycerols. In addition, we found formation of CEs in Mycobacterium tuberculosis when it was grown with cholesterol plus an additional fatty acid substrate. This study provides a basis for the application of bacterial whole-cell systems in the biotechnological production of SEs for use in functional foods and cosmetics.Importance: Oleaginous bacteria exhibit great potential for the production of high-value neutral lipids, such as triacylglycerols and wax esters. This study describes the formation of steryl esters (SEs) as neutral lipid storage compounds in sterol-degrading oleaginous bacteria, providing a basis for biotechnological production of SEs using bacterial systems with potential applications in the functional food, nutraceutical, and cosmetic industries. We found cholesteryl ester (CE) formation in several sterol-degrading Actino- and Proteobacteria under nitrogen-limiting conditions, suggesting an important role of this process in storing energy and carbon under adverse conditions. In addition, Mycobacterium tuberculosis grown on cholesterol accumulated CEs in the presence of an additional fatty acid substrate.Holliday, V.T., Bartlein, P.J., Scott, A.C., Marlon, J.R., 2020. Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ～12,800 years ago, Parts 1 and 2: A discussion. The Journal of Geology 128, 69-94. et al. published two papers on the Younger Dryas Impact Hypothesis (YDIH)—the paleoenvironmental effects of a purported cosmic impact at the beginning of the Younger Dryas Chronozone (YDC). Part 1 includes a selective summary of previous discussions of the YDIH but leaves out key reviews, uncritically accepts previous interpretations of purported impact, and fails to take into account abundant criticisms and contradictory data. A discussion of ice-core evidence focuses only on the beginning of the YDC rather than on a longer interval that would allow the context of claimed impact indicators to be evaluated. The exceptionalism claimed for many of the key data points is the result of exaggerations, and the graphical analyses themselves are not reproducible. Part 2 presents data from sedimentary records. The authors assume that impacts triggered widespread fires, but the evidence for such a link between extraterrestrial impacts and wildfires is weak. The presence of charcoal at the beginning of the YDC (YDB) fails to unambiguously support the hypothesis of impact-related fires because there is also a large peak at the end of the YDC. Stratigraphic markers used to argue for widespread burning, such as the Usselo soil of northwest Europe and the black mat of the southwestern United States, were shown by their original investigators to have no plausible link to an impact event. Human population decline in North America is not supported by abundant published archaeological, geochronological, and stratigraphic evidence. Late Pleistocene megafauna extinctions varied in time for individual species across the Americas, Europe, and Asia and thus cannot be accounted for by a single impact. If there was some sort of extraterrestrial YDB-age event, it apparently had negligible terrestrial impact.Discussion of: Wolbach, W.S., Ballard, J.P., Mayewski, P.A., Adedeji, V., Bunch, T.E., Firestone, R.B., French, T.A., Howard, G.A., Israde-Alcántara, I., Johnson, J.R., Kimbel, D., Kinzie, C.R., Kurbatov, A., Kletetschka, G., LeCompte, M.A., Mahaney, W.C., Melott, A.L., Maiorana-Boutilier, A., Mitra, S., Moore, C.R., Napier, W.M., Parlier, J., Tankersley, K.B., Thomas, B.C., Wittke, J.H., West, A., Kennett, J.P., 2018. Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ～12,800 years ago. 1. Ice cores and glaciers. The Journal of Geology 126, 165-184.Wolbach, W.S., Ballard, J.P., Mayewski, P.A., Parnell, A.C., Cahill, N., Adedeji, V., Bunch, T.E., Domínguez-Vázquez, G., Erlandson, J.M., Firestone, R.B., French, T.A., Howard, G., Israde-Alcántara, I., Johnson, J.R., Kimbel, D., Kinzie, C.R., Kurbatov, A., Kletetschka, G., LeCompte, M.A., Mahaney, W.C., Melott, A.L., Mitra, S., Maiorana-Boutilier, A., Moore, C.R., Napier, W.M., Parlier, J., Tankersley, K.B., Thomas, B.C., Wittke, J.H., West, A., Kennett, J.P., 2018. Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ～12,800 years ago. 2. Lake, marine, and terrestrial sediments. The Journal of Geology 126, 185-205.Hou, H., Shao, L., Tang, Y., Zhao, S., Yuan, Y., Li, Y., Mu, G., Zhou, Y., Liang, G., Zhang, J., 2020. Quantitative characterization of low-rank coal reservoirs in the southern Junggar Basin, NW China: Implications for pore structure evolution around the first coalification jump. Marine and Petroleum Geology 113, 104165. assessment of coalbed methane (CBM) reservoirs can provide insights into the evolution of the pore structure systems around the first coalification jump (FCJ). The southern Junggar Basin, a typical low-rank coal-bearing basin in northwestern China, has been of interest to scientists and policy-makers due to its abundance of CBM resources and favourable conditions for CBM enrichment. A total of 28 coal samples from the Middle Jurassic Xishanyao Formation collected from 11 sampling sites in the central segment of the southern Junggar Basin were analyzed in this study. These samples were quantitatively characterized and comprehensively evaluated using macroscopic to nanometer-scale methods including macroscopic coal description, proximate analysis, vitrinite reflectance measurements, maceral analysis, low pressure nitrogen adsorption (LPNA), scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP) and nuclear magnetic resonance (NMR). The results show that the Xishanyao low-rank coals are characterized by low moisture contents, low or low-medium ash yields (eastern and western parts), high volatile matter contents, moderate vitrinite contents, and high inertinite contents. The physical property of the Xishanyao coals generally displays heterogeneity, with the specific surface area, the total pore volume, the air permeability and the transverse relaxation time (T2) ranging from 0.116 to 15.983 m2/g, 0.461 × 10?3 to 13.37 × 10?3 cm3/g, 0.001 to 151.66 mD (0.987 × 10?6 to 0.149 μm2) and 1.44–174.22 ms, respectively. A new parameter, namely micropore volume proportion per unit nano-meter, is proposed. Micropore and transition pore volume per nm, specific surface area, total pore volume, DN1 and DN2 (LPNA fractal dimension) all first increase, then decrease and finally increase with rising coal rank, while the maximum and minimum values of the maximum vitrinite reflectance (Ro, max) occur at 0.58–0.59% and 0.65–0.66%. The boundary of Ro, max corresponding to the FCJ can be further defined from 0.5-0.6% to 0.58–0.59% based on the evolution of adsorption pore structures. Thus, pore structure parameters related to adsorption capacity are controlled predominantly by coal rank. In addition, tectonic deformation has a strong impact on seepage pore structure but only a slight impact on that of adsorption pore, which leads to an ambiguous correlation or a complex trend between mesopore, macropore content, DMIP (fractal dimension of MIP) and coal rank around the FCJ. This study reveals the complex variation of pore structure evolution of low-rank coals and the significant influence of the FCJ on physical properties of coalbed methane reservoirs.Hu, Y., Cai, C., Pederson, C.L., Liu, D., Jiang, L., He, X., Shi, S., Immenhauser, A., 2020. Dolomitization history and porosity evolution of a giant, deeply buried Ediacaran gas field (Sichuan Basin, China). Precambrian Research 338, 105595. deeply buried (>7 km) upper Ediacaran (Sinian) Dengying Formation (ca. 551.1-541 Ma) in the Sichuan Basin, China, is the largest Precambrian dolostone gas reservoir worldwide. Gas exploration from the Dengying Formation, however, is hampered by a limited understanding of its complex dolomitization history and porosity evolution. New petrological, geochemical and petrophysical analyses were performed and are discussed here to develop a better understanding of the formation’s complexities. Microbialite, dolo-grainstone, and crystalline dolostone lithologies from the platform margin have high primary porosities relative to dolo-mudstone and less common microbialite lithologies from the low-energy platform interior. Spatially-variable primary porosity was subsequently overprinted by meteoric dissolution and dolomitization, often inducing secondary porosity. The various forms of dolomitization (sabkha, reflux, and burial dolomitization, and cementation) increased the resistivity of these rocks to chemical and physical compaction and porosity destruction. In the deep burial domain, medium- to coarse-crystalline dolomite cements and saddle dolomite precipitated at fluid temperatures of 120-160℃ and 160-220℃, respectively. The significance of deep burial dissolution is critically discussed and constrained by: (i) corrosion of late diagenetic minerals, (ii) pores cross-cutting (or forming around) stylolites, and (iii) the occurrence of solid bitumen in the center of secondary pores. Vuggy, inter- and intracrystalline pores developed during a late and deep burial stage, and comprise ca. 20% of the overall Dengying reservoir porosity. Mechanisms which induced corrosion at this burial stage include hydrothermal pulses and thermochemical sulfate reduction. Similar to many carbonate reservoirs in the Phanerozoic, this study documents that the platform margin has better porosities and higher gas production compared to the platform interior due to its specific carbonate rock properties and diagenesis. Data shown here document the complex multiphase dolomitization history and high potential for gas production from deeply buried Precambrian dolostone reservoirs.Huang, H., Wang, X., Gong, S., Krake, N., Jin, M., Li, N., Birgel, D., Peckmann, J., Cheng, M., Roberts, H.H., Chen, D., Feng, D., 2020. New constraints on the formation of hydrocarbon-derived low magnesium calcite at brine seeps in the Gulf of Mexico. Sedimentary Geology 398, 105572. brine seeps – representing extreme environments typified by halophilic and chemotrophic organisms – may provide insight into the ecology of microorganisms on an early Earth and possibly other planetary bodies. Authigenic low magnesium calcite (LMC) is common at brine seeps and represents an archive of fluid compositions, fluid origin, and the conditions under which this carbonate mineral formed. Here we present the analysis of authigenic LMC from three hydrocarbon-rich brine seeps (GB260, ~460?m; GB697, ~1280?m; AC601, ~2340?m) from the Gulf of Mexico. The formation of LMC was favored by brine fluids with extremely low Mg/Ca mole ratios (e.g. <2) relative to seawater (Mg/Ca mole ratio of ~5.2). Petrographic observations reveal that the studied LMC is of primary origin. Its δ13C values vary from ?53.5‰ to 14.0‰, indicating variable carbon sources that include 13C-depleted methane, crude oil, seawater dissolved inorganic carbon, and 13C-enriched residual carbonate species reflecting methanogenesis. In contrast, LMC shows predominantly relatively high δ13Corg values (from ?39.0‰ to ?25.7‰), suggesting an unrecognized local source of nutrients fueling the local production of biomass. The δ18O values of LMC (as high as 6.0‰) are too high for precipitation in equilibrium with seawater, probably reflecting the involvement of deep formation fluids. The wide range of 87Sr/86Sr ratios and the enrichment of Sr and Ba in LMC is in accordance with pore fluids deriving from the dissolution of the Louann salt or alteration of silicates in deep sediments. Given the stability of LMC, its petrographic and geochemical characterization achieved in this study can be used to better constrain brine seep activities throughout the geological record.Huang, Z., Zhang, S., Yang, R., Wu, X., Li, R., Zhang, H., Hung, P., 2020. A review of liquid nitrogen fracturing technology. Fuel 266, 117040. fracturing is an efficient stimulation means for the exploitation of unconventional oil/gas resources as well as geothermal energy. However, there are several issues for traditional hydraulic fracturing, e.g. excessive water consumption, formation damage and flow-back-fluid contamination. In recent decades, these problems have led research efforts to investigate waterless fracturing technology as an alternative to traditional hydraulic methods. Liquid nitrogen (LN2) is considered as one of the potential water-free fracturing fluids. Due to its unique low-temperature characteristics, severe thermal stress will be created in the rock under down-hole conditions during the LN2 fracturing process. As a result, not only several primary fractures, but also secondary cracks perpendicular to the primary fractures can be generated in a reservoir, creating a more complicated fracture network than that in conventional hydraulic fracturing. This review aims to outline the current developments of LN2 fracturing technology from several aspects, including the effect of thermal shock on rock physical properties, the heat transfer characteristics of LN2, the rock-breaking performance of an LN2 jet, and the applications and limitations of cryogenic fracturing technology. Simulation studies, laboratory experiments and field application cases are discussed to evaluate the LN2 fracturing technology.Huang, Z., Zhang, Y., Xie, L., Zhao, P., He, B., Ren, L., 2020. Comparative study of porosity test methods for shale. Arabian Journal of Geosciences 13, 94. is important in the assessment of gas shale reservoirs and has been widely tested as a basic characteristic of shale. Different test methods were employed to test the porosity, yet inconsistencies were found among the samples, testing methods, and researches in the Longmaxi Formation of the Sichuan Basin. In this paper, in order to determine the source of the inconsistencies, seven test methods are undertaken and the test results are compared intensely. The results show that the inconsistencies are due to sampling variations, test method limits, and sample sizes. It is suggested to test porosity with a relative big sample and by the method capable of covering a broad test range, to reduce the influence of sampling, testing method limit, and sample size. Furthermore, it needs to notice the test protocol, which can introduce unachieved status. Especially the water saturation has significant effect on shale porosity. In addition, the drying-wetting cycles could induce cracks in shale as well; hence, it is important to store the samples carefully, avoiding artificial porosity.Hull, P.M., Bornemann, A., Penman, D.E., Henehan, M.J., Norris, R.D., Wilson, P.A., Blum, P., Alegret, L., Batenburg, S.J., Bown, P.R., Bralower, T.J., Cournede, C., Deutsch, A., Donner, B., Friedrich, O., Jehle, S., Kim, H., Kroon, D., Lippert, P.C., Loroch, D., Moebius, I., Moriya, K., Peppe, D.J., Ravizza, G.E., R?hl, U., Schueth, J.D., Sepúlveda, J., Sexton, P.F., Sibert, E.C., ?liwińska, K.K., Summons, R.E., Thomas, E., Westerhold, T., Whiteside, J.H., Yamaguchi, T., Zachos, J.C., 2020. On impact and volcanism across the Cretaceous-Paleogene boundary. Science 367, 266-272.: The cause of the end-Cretaceous mass extinction is vigorously debated, owing to the occurrence of a very large bolide impact and flood basalt volcanism near the boundary. Disentangling their relative importance is complicated by uncertainty regarding kill mechanisms and the relative timing of volcanogenic outgassing, impact, and extinction. We used carbon cycle modeling and paleotemperature records to constrain the timing of volcanogenic outgassing. We found support for major outgassing beginning and ending distinctly before the impact, with only the impact coinciding with mass extinction and biologically amplified carbon cycle change. Our models show that these extinction-related carbon cycle changes would have allowed the ocean to absorb massive amounts of carbon dioxide, thus limiting the global warming otherwise expected from postextinction volcanism.Editor's Summary: An impact with a dash of volcanism. Around the time of the end-Cretaceous mass extinction that wiped out dinosaurs, there was both a bolide impact and a large amount of volcanism. Hull et al. ran several temperature simulations based on different volcanic outgassing scenarios and compared them with temperature records across the extinction event. The best model fits to the data required most outgassing to occur before the impact. When combined with other lines of evidence, these models support an impact-driven extinction. However, volcanic gases may have played a role in shaping the rise of different species after the extinction event.Ibrahim, I.M., Konnova, S.A., Sigida, E.N., Lyubun, E.V., Muratova, A.Y., Fedonenko, Y.P., Elbanna, К., 2020. Bioremediation potential of a halophilic Halobacillus sp. strain, EG1HP4QL: exopolysaccharide production, crude oil degradation, and heavy metal tolerance. Extremophiles 24, 157-166. halophilic bacterial strain, EG1HP4QL, was isolated from a salt sample from Lake Qarun, Fayoum Province, Egypt. Morphological, physiological, biochemical, and phylogenetic analyses indicated that the strain belonged to the genus Halobacillus. Strain EG1HP4QL produced an extracellular polysaccharide (EPS), with production peaking (5.9 g L?1) during growth on medium S-G containing 2% (w/v) sucrose at 35 °C (pH 8.0). The EPS had significant emulsifying activity (E24 %) against kerosene (65.7?±?0.8%), o-xylene (64.0?±?1%), and sunflower oil (44.7?±?0.5%). The composition of the EPS included two polymers—a negatively charged and a neutral one (~ 3:1)—in which mannose and glucose were the main neutral monosaccharide constituents. Strain EG1HP4QL was able to utilize crude oil (35.3%) as the sole carbon source within 12 days. The minimum inhibitory concentrations of heavy metals [Zn(II), Cd(II), Pb(II), Ni(II), and Cu(II)] for strain EG1HP4QL were 1.0, 2.0, 2.0, 2.5, and 5 mM, respectively.Igarashi, K., Miyako, E., Kato, S., 2020. Direct interspecies electron transfer mediated by graphene oxide-based materials. Frontiers in Microbiology 10, 3068. doi: 10.3389/fmicb.2019. 03068.. 03068Conductive materials are known to promote direct interspecies electron transfer (DIET) by electrically bridging microbial cells. Previous studies have suggested that supplementation of graphene oxide (GO) based materials, including GO, and reduced GO (rGO), to anaerobic microbial communities, can promote DIET. This promotion mechanism is thought to be involved in electron transfer via rGO or biologically formed rGO. However, concrete evidence that rGO directly promotes DIET is still lacking. Furthermore, the effects of the physicochemical properties of GO-based materials on DIET efficiency have not been elucidated. In the current work, we investigated whether chemically and biologically reduced GO compounds can promote DIET in a defined model coculture system, and also examined the effects of surface properties on DIET-promoting efficiency. Supplementation of GO to a defined DIET coculture composed of an ethanol-oxidizing electron producer Geobacter metallireducens and a methane-producing electron consumer Methanosarcina barkeri promoted methane production from ethanol. X-ray photoelectron spectroscopy revealed that GO was reduced to rGO during cultivation by G. metallireducens activity. The stoichiometry of methane production from ethanol and the isotope labeling experiments clearly showed that biologically reduced GO induced DIET-mediated syntrophic methanogenesis. We also assessed the DIET-promoting efficiency of chemically reduced GO and its derivatives, including hydrophilic amine-functionalized rGO (rGO-NH2) and hydrophobic octadecylamine-functionalized rGO (rGO-ODA). While all tested rGO derivatives induced DIET, the rGO derivatives with higher hydrophilicity showed higher DIET-promoting efficiency. Optical microscope observation revealed that microbial cells, in particular, G. metallireducens, more quickly adhered to more hydrophilic GO-based materials. The superior ability to recruit microbial cells is a critical feature of the higher DIET-promoting efficiency of the hydrophilic materials. This study demonstrates that biologically and chemically reduced GO can promote DIET-mediated syntrophic methanogenesis. Our results also suggested that the surface hydrophilicity (i.e., affinity toward microbial cells) is one of the important determinants of the DIET-promoting efficiencies. These observations will provide useful guidance for the selection of conductive particles for the improvement of methanogenesis in anaerobic digesters.Imachi, H., Nobu, M.K., Nakahara, N., Morono, Y., Ogawara, M., Takaki, Y., Takano, Y., Uematsu, K., Ikuta, T., Ito, M., Matsui, Y., Miyazaki, M., Murata, K., Saito, Y., Sakai, S., Song, C., Tasumi, E., Yamanaka, Y., Yamaguchi, T., Kamagata, Y., Tamaki, H., Takai, K., 2020. Isolation of an archaeon at the prokaryote–eukaryote interface. Nature 577, 519-525. origin of eukaryotes remains unclear. Current data suggest that eukaryotes may have emerged from an archaeal lineage known as ‘Asgard’ archaea. Despite the eukaryote-like genomic features that are found in these archaea, the evolutionary transition from archaea to eukaryotes remains unclear, owing to the lack of cultured representatives and corresponding physiological insights. Here we report the decade-long isolation of an Asgard archaeon related to Lokiarchaeota from deep marine sediment. The archaeon—‘Candidatus Prometheoarchaeum syntrophicum’ strain MK-D1—is an anaerobic, extremely slow-growing, small coccus (around 550 nm in diameter) that degrades amino acids through syntrophy. Although eukaryote-like intracellular complexes have been proposed for Asgard archaea, the isolate has no visible organelle-like structure. Instead, Ca. P. syntrophicum is morphologically complex and has unique protrusions that are long and often branching. On the basis of the available data obtained from cultivation and genomics, and reasoned interpretations of the existing literature, we propose a hypothetical model for eukaryogenesis, termed the entangle–engulf–endogenize (also known as E3) model.Iyer, J., Chen, X., Carroll, S.A., 2020. Impact of chemical and mechanical processes on leakage from damaged wells in CO2 storage sites. Environmental Science & Technology 54, 1196-1203. perceived risk of CO2 leakage through wells has been considered a potential limitation to commercial scale deployment of geologic CO2 storage. However, chemical and mechanical alteration of cement can reduce the permeability of leakage pathways. We conducted 100s of simulations spanning realistic operating conditions and well-damage characteristics to understand (1) under what conditions and time frames do fractures seal and (2) for fractures that do not seal, how quickly and to what extent is the permeability reduced. For the conditions simulated, fractures with apertures in the tens of microns seal while those greater than hundreds of microns may exhibit long-term leakage. Fractures with apertures between 10 and 500 μm took a few days to a couple of years to seal. For non-sealing fractures mechanical deformation of altered asperities can rapidly reduce permeability. A sealing criterion was developed to relate fracture aperture with the cemented length required for self-sealing. Longer cemented intervals can seal large fractures; however, they take longer to seal and leak larger volumes before sealing. While the results presented here are subject to uncertainties, the manuscript provides a framework in which a model can be used to quantitatively answer questions regarding well integrity to facilitate decision making.Jacquemot, P., Viennet, J.-C., Bernard, S., Le Guillou, C., Rigaud, B., Delbes, L., Georgelin, T., Jaber, M., 2019. The degradation of organic compounds impacts the crystallization of clay minerals and vice versa. Scientific Reports 9, 20251. our capabilities to unambiguously identify ancient traces of life in ancient rocks requires laboratory experiments to better constrain the evolution of biomolecules during advanced fossilization processes. Here, we submitted RNA to hydrothermal conditions in the presence of a gel of Al-smectite stoichiometry at 200?°C for 20 days. NMR and STXM-XANES investigations revealed that the organic fraction of the residues is no longer RNA, nor the quite homogeneous aromatic-rich residue obtained in the absence of clays, but rather consists of particles of various chemical composition including amide-rich compounds. Rather than the pure clays obtained in the absence of RNA, electron microscopy (SEM and TEM) and diffraction (XRD) data showed that the mineralogy of the experimental residues includes amorphous silica and aluminosilicates mixed together with nanoscales phosphates and clay minerals. In addition to the influence of clay minerals on the degradation of organic compounds, these results evidence the influence of the presence of organic compounds on the nature of the mineral assemblage, highlighting the importance of fine-scale mineralogical investigations when discussing the nature/origin of organo-mineral microstructures found in ancient rocks.Janssen, D.J., Rickli, J., Quay, P.D., White, A.E., Nasemann, P., Jaccard, S.L., 2020. Biological control of chromium redox and stable isotope composition in the surface ocean. Global Biogeochemical Cycles 34, e2019GB006397. chromium stable isotopes (δ53Cr) have received significant attention for their utility as a tracer of oxygen availability in the distant geological past, a mechanistic understanding of modern oceanic controls on Cr and δ53Cr is still lacking. Here we present total dissolved δ53Cr, concentrations of Cr (III) and total dissolved Cr, and net community productivity (NCP) from the North Pacific. Chromium concentrations show surface depletions in waters with elevated NCP, but not in lower productivity waters. Observed Cr deficits correspond well with calculated Cr export derived from NCP and Cr:C ratios of natural phytoplankton and marine particulates. Chromium (III) concentrations are stable over the diel cycle yet correlate with NCP, with maxima found in highly productive surface waters but not in lower productivity waters, indicating biological control on Cr (III). The relationship between Cr (III) and δ53Cr suggests that δ53Cr distributions may be controlled by the removal of isotopically light Cr (III) at an isotopic enrichment factor (?53Cr) of ?1.08‰ ± 0.25 relative to total dissolved δ53Cr, in agreement with the global δ53Cr‐Cr fractionation factor (?0.82‰ ± 0.05). No perturbation to δ53Cr, Cr, or Cr (III) is observed in oxygen‐depleted waters (~10 μmol/kg), suggesting no strong control by O2 availability, in agreement with other recent studies. Therefore, we propose that biological productivity is the primary control on Cr and δ53Cr in the modern ocean. Consequently, δ53Cr records in marine sediments may not faithfully record oxygen availability in the Late Quaternary. Instead, our data demonstrate that δ53Cr records may be a useful tracer for biological productivity.Jayakumar, A., Ward, B.B., 2020. Diversity and distribution of nitrogen fixation genes in the oxygen minimum zones of the world oceans. Biogeosciences Discussions 2020, 1-28. and community composition of nitrogen fixing microbes in the three main oxygen minimum zones (OMZs) of the world ocean were investigated using operational taxonomic unit (OTU) analysis of nifH clone libraries. Representatives of the all four main clusters of nifH genes were detected. Cluster I sequences were most diverse in the surface waters and the most abundant OTUs were affiliated with Alpha- and Gammaproteobacteria. Cluster II, III, IV assemblages were most diverse at oxygen depleted depths and none of the sequences were closely related to sequences from cultivated organisms. The OTUs were biogeographically distinct for the most part – there was little overlap among regions, between depths or between cDNA and DNA. Only a few cyanobacterial sequences were detected. The prevalence and diversity of microbes that harbour nifH genes in the OMZ regions, where low rates of N fixation are reported, remains an enigma.Jiang, Y., Hu, H., Gluyas, J., Zhao, K., 2019. Distribution characteristics and accumulation model for the coal-formed gas generated from Permo-Carboniferous coal measures in Bohai Bay Basin, China: A review. Acta Geologica Sinica - English Edition 93, 1869-1884.‐formed gas generated from the Permo‐Carboniferous coal measures has become one of the most important targets for deep hydrocarbon exploration in the Bohai Bay Basin, offshore eastern China. However, the proven gas reserves from this source rock remain low to date, and the distribution characteristics and accumulation model for the coal‐formed gas are not clear. Here we review the coal‐formed gas deposits formed from the Permo‐Carboniferous coal measures in the Bohai Bay Basin. The accumulations are scattered, and dominated by middle‐small sized gas fields, of which the proven reserves ranging from 0.002 to 149.4×108 m3 with an average of 44.30×108 m3 and a mid‐point of 8.16×108 m3. The commercially valuable gas fields are mainly found in the central and southern parts of the basin. Vertically, the coal‐formed gas is accumulated at multiple stratigraphic levels from Paleogene to Archaeozoic, among which the Paleogene and Permo‐Carboniferous are the main reservoir strata. According to the transporting pathway, filling mechanism and the relationship between source rocks and reservoir, the coal‐formed gas accumulation model can be defined into three types: “Upward migrated, fault transported gas” accumulation model, “Laterally migrated, sandbody transported gas” accumulation model, and “Downward migrated, sub‐source, fracture transported gas” accumulation model. Source rock distribution, thermal evolution and hydrocarbon generation capacity are the fundamental controlling factors for the macro distribution and enrichment of the coal‐formed gas. The fault activity and the configuration of fault and caprock control the vertical enrichment pattern.Jiao, X., Liu, Y.-q., Yang, W., Zhou, D.-w., Bai, B., Zhang, T.-s., Zhao, M.-r., Li, Z.-x., Meng, Z.-y., Yang, Y.-y., Li, Z.-x., 2020. Fine-grained volcanic-hydrothermal sedimentary rocks in Permian Lucaogou Formation, Santanghu Basin, NW China: Implications on hydrocarbon source rocks and accumulation in lacustrine rift basins. Marine and Petroleum Geology 114, 104201. volcanic-hydrothermal field is a complex hybrid geological system, where sediments originated from volcanic, hydrothermal, lacustrine, terrestrial, and biotic sources are mixed. Recent petrological studies on such sediments have indicated a potential relationship between volcanic-hydrothermal activities and oil generation and accumulation. Here, we explore the mechanisms of sedimentation and oil accumulation in well-laminated organic-rich fine-grained sedimentary rocks in Permian Lucaogou Formation deposited in the lacustrine Santanghu rift basin, NW China. We conducted petrographic, carbon and oxygen isotopic, and organic geochemical analyses of fifty-four core samples from three wells (forty-eight samples from Well W1, two from W2, four from W3) designed for tight oil exploration. Four main observations and interpretations are: 1) The fine-grained sediments are a mixture of volcanic-hydrothermal detrital feldspar grains, authigenic quartz crystals, and primary lacustrine dolomite, forming interbedded tuffaceous shale and dolostone; 2) authigenic quartz crystals were precipitated from acidic hydrothermal fluids, whereas fine-grained angular alkaline feldspars were derived from subaqueous volcanic eruption; 3) the TOC content and oil generation potential increase with increased mixing of feldspars and carbonate minerals. Hence, the dolomite-bearing tuffaceous shale and tuffaceous dolostone are the best source rocks; and 4) the fine-grained sedimentary rocks are interpreted as a subaqueous volcanic-hydrothermal deposit that controls the source potential. The sedimentary processes of an ancient sediment-hosted geothermal system and its implications on hydrocarbon source rocks and accumulation were first identified. Algal bloom induced by subaqueous eruptions is the main cause for episodic deposition of organic matter and extreme heterogeneity in both lithofacies and source-rock distribution. The results suggest that cone-shaped buildups on seismic sections, which were formed by volcanic-hydrothermal deposits and contain highly-mixed feldspar and carbonate sediments, are the best hydrocarbon reservoirs, and demonstrate a strong relationship between volcanic-hydrothermal activities and hydrocarbon accumulation in an extensional tectonic setting.Jin, Y., Kida, M., Yoneda, J., Konno, Y., Oshima, M., Tenma, N., Nagao, J., 2020. Natural gas hydrates recovered from the Umitaka Spur in the Joetsu Basin, Japan: Coexistence of two structure-I hydrates with distinctly different textures and gas compositions within a massive structure. ACS Earth and Space Chemistry 4, 77-85. study evaluated natural gas hydrates recovered from three different wells (J13R, J07RB, and J23R) at the Umitaka Spur in the Joetsu Basin, via Raman spectroscopy. The hydrates in two of the samples (J13R-13P and J07RB-5P) were of the particle displacement type, whereas sample J23R-3P displayed hydrates of the massive type. The hydrate crystals in all three samples contained a structure-I (sI) hydrate that primarily captures methane (CH4) molecules with ethane (C2H6), carbon dioxide (CO2), and/or hydrogen sulfide (H2S), which were observable using powder X-ray diffraction and Raman spectroscopy techniques. In the massive type J23R-3P sample, two hydrate crystals with different textures were found to coexist, with one displaying an icy appearance and the other a columnar shape. Interestingly, the icy J23R-3P crystals were sI hydrates containing mostly CH4 with C2H6, CO2, and H2S, whereas the columnar J23R-3P crystals were sI CH4 hydrates containing few other guest molecules. The coexistence of two different hydrates was not observed in the nodule type sediment (J13R-13P and J07RB-5P). Isotopic results suggested that the CH4 molecules in the icy and columnar J23R-3P crystals originated from different CH4 sources. Different sI crystals coexisting in the same sample would be because of high CH4 flux, a known feature in the Umitaka Spur.Jin, Z., Wang, L., Zuidema, E., Mondal, K., Zhang, M., Zhang, J., Wang, C., Meng, X., Yang, H., Mesters, C., Xiao, F.-S., 2020. Hydrophobic zeolite modification for in situ peroxide formation in methane oxidation to methanol. Science 367, 193-197.: Selective partial oxidation of methane to methanol suffers from low efficiency. Here, we report a heterogeneous catalyst system for enhanced methanol productivity in methane oxidation by in situ generated hydrogen peroxide at mild temperature (70°C). The catalyst was synthesized by fixation of AuPd alloy nanoparticles within aluminosilicate zeolite crystals, followed by modification of the external surface of the zeolite with organosilanes. The silanes appear to allow diffusion of hydrogen, oxygen, and methane to the catalyst active sites, while confining the generated peroxide there to enhance its reaction probability. At 17.3% conversion of methane, methanol selectivity reached 92%, corresponding to methanol productivity up to 91.6 millimoles per gram of AuPd per hour.Editor's summary: Confining peroxide to make methanol. In principle, hydrogen peroxide would be an efficient oxidant for the conversion of methane to methanol under mild conditions. In practice, however, it is currently too expensive to produce the peroxide ahead of time for this purpose. Jin et al. report a catalyst system that generates and concentrates hydrogen peroxide for immediate reaction with methane. A hydrophobically coated zeolite keeps the peroxide close to the gold and palladium active site, where incoming methane is then selectively oxidized to methanol.Jing, Z., Balucan, R.D., Underschultz, J.R., Pan, S., Steel, K.M., 2020. Chemical stimulation for enhancing coal seam permeability: Laboratory study into permeability variation and coal structure examination. International Journal of Coal Geology 219, 103375. potential coalbeds have sub-economic permeability for coal seam gas (CSG) extraction even though all the other key characteristics (gas content, thickness etc.) can meet the requirement for successful production. To enhance coal seam permeability various CSG stimulation techniques, including hydraulic fracturing, cavity well completions and horizontal wells, have been used, but none is ubiquitously successful. The potential of chemical stimulation including both acid (1% HCl) and oxidant (1% NaClO) stimulation are examined in this paper as an alternative method to enhance coal seam permeability. Acid stimulation targets the removal of certain minerals in coal cleats, while the oxidant dissolves the coal matrix, thereby etching pre-existing coal cleats and perhaps forming new ones. The permeability variation during stimulations are measured with core flooding tests and the corresponding coal structural changes are examined using X-ray microcomputed tomography (μCT) technique. The chemical reaction mechanisms are confirmed by elemental analysis via inductively coupled plasma optical emission spectroscopy (ICP-OES) and dissolved organic carbon (DOC) in the effluent.Acid stimulation was performed horizontally with cube samples cut from coal cores (Bowen Basin, Australia) and it exhibited a positive effect on coal permeability, which is proposed to result from demineralisation as shown by before and after CT scanning observations together with high calcium (Ca) content in the effluent. NaClO oxidation was able to etch pre-existing coal cleat surfaces, widen cleat apertures and generate new horizontal fractures and/or void space. These changes were caused primarily by chemical attack, confirmed by the high DOC concentration in the effluent. Oxidant stimulation caused a decrease in vertical permeability and an increase in horizontal permeability for some cores. The decrease in permeability is proposed to be due to a combination of increased void space weakening the coal associated with movement of the coal into newly created space against confining pressure. Minerals in the cleats appear to play a role keeping void space open and preventing collapse under confining pressure. Furthermore, the results for these samples indicate that NaClO oxidation appears to be lithotype independent and preferentially attacks coal sections that have more initial pores or fractures.Joachimski, M.M., Alekseev, A.S., Grigoryan, A., Gatovsky, Y.A., 2019. Siberian Trap volcanism, global warming and the Permian-Triassic mass extinction: New insights from Armenian Permian-Triassic sections. GSA Bulletin 132, 427-443. boundary sections from Armenia were studied for carbon isotopes of carbonates as well as oxygen isotopes of conodont apatite in order to constrain the global significance of earlier reported variations in the isotope proxies and elaborate the temporal relationship between carbon cycle changes, global warming and Siberian Trap volcanism. Carbon isotope records of the Chanakhchi and Vedi II sections show a 3–5‰ negative excursion that start in the Clarkina nodosa (C. yini) conodont Zone (latest Permian) with minimum values recorded in Hindeodus parvus to Isarcicella isarcica conodont zones (earliest Triassic). Sea surface temperatures (SST) reconstructed from oxygen isotopes of conodont apatite increase by 8–10 °C over an extrapolated time interval of ～39 ka with the onset of global warming occurring in the C. iranica (C. meishanensis) Zone of the latest Permian. Climate warming documented in the Armenian sections is comparable to published time-equivalent shifts in SST in Iran and South China suggesting that this temperature change represents a true global signature. By correlating the Armenian and Iranian section with the radiometrically well-dated Meishan GSSP (Global Stratotype Section and Point) section (South China), the negative shift in δ13C is estimated to have occurred 12–128 ka prior to the onset of global warming. This temporal offset is unexpected given the synchrony in changes in atmospheric CO2 and global temperature as seen in Pleistocene ice core records. The negative δ13C excursion is explained by the addition of emission of isotopically light CO2 and CH4 from thermogenic heating of organic carbon-rich sediments by Siberian Trap sill intrusions. However, the observed time lag in the δ13C and δ18O shifts questions the generally assumed cause-effect relationship between emission of thermogenically produced greenhouse gases and global warming. The onset of temperature rise coincides with a significant enrichment in Hg/TOC (total organic carbon) ratios arguing for a major volcanic event at the base of the extinction interval. Whether global warming was a major factor for the Late Permian mass extinction depends on the duration of the extinction interval. Warming only starts at the base of the extinction interval, but with the extinction encompassing a time interval of 60 ± 48 ka, global climate warming in conjunction with temperature-related stressors as hypoxia and reduced nutrient availability may have been one of the major triggers of the most devastating biotic crisis in Earth history.Johannessen, S.C., Greer, C.W., Hannah, C.G., King, T.L., Lee, K., Pawlowicz, R., Wright, C.A., 2020. Fate of diluted bitumen spilled in the coastal waters of British Columbia, Canada. Marine Pollution Bulletin 150, 110691. is public concern about the behaviour of spilled diluted bitumen (dilbit) in marine and estuarine waters. We provide a preliminary assessment of the results of laboratory experiments and models, in the context of environmental conditions in the coastal waters of British Columbia. Most dilbit spilled within this region would likely float at the surface and be transported to shore by winds and currents. Fresh dilbit is too light to sink in coastal waters. Highly weathered dilbit could sink where salinity is less than 14, typically only near river mouths and in the top 1–3?m of fjords after heavy rainfall. Subsurface plumes of weathered dilbit could re-emerge at the surface. Sinking oil-particle aggregates are unlikely to form in coastal waters. However, dilbit could be entrained below the surface by wave mixing during storms and to depths of 150?m by coherent mixing in the Haro Strait tidal convergence zone.Johnsen, U., Sutter, J.-M., Reinhardt, A., Pickl, A., Wang, R., Xiang, H., Sch?nheit, P., 2020. D-Ribose catabolism in archaea: Discovery of a novel oxidative pathway in Haloarcula species. Journal of Bacteriology 202, e00608-19.: The Haloarcula species H. marismortui and H. hispanica were found to grow on d-ribose, d-xylose, and l-arabinose. Here, we report the discovery of a novel promiscuous oxidative pathway of pentose degradation based on genome analysis, identification and characterization of enzymes, transcriptional analysis, and growth experiments with knockout mutants. Together, the data indicate that in Haloarcula spp., d-ribose, d-xylose, and l-arabinose were degraded to α-ketoglutarate involving the following enzymes: (i) a promiscuous pentose dehydrogenase that catalyzed the oxidation of d-ribose, d-xylose, and l-arabinose; (ii) a promiscuous pentonolactonase that was involved in the hydrolysis of ribonolactone, xylonolactone, and arabinolactone; (iii) a highly specific dehydratase, ribonate dehydratase, which catalyzed the dehydration of ribonate, and a second enzyme, a promiscuous xylonate/gluconate dehydratase, which was involved in the conversion of xylonate, arabinonate, and gluconate. Phylogenetic analysis indicated that the highly specific ribonate dehydratase constitutes a novel sugar acid dehydratase family within the enolase superfamily; and (iv) finally, 2-keto-3-deoxypentanonate dehydratase and α-ketoglutarate semialdehyde dehydrogenase catalyzed the conversion of 2-keto-3-deoxypentanonate to α-ketoglutarate via α-ketoglutarate semialdehyde. We conclude that the expanded substrate specificities of the pentose dehydrogenase and pentonolactonase toward d-ribose and ribonolactone, respectively, and the presence of a highly specific ribonate dehydratase are prerequisites of the oxidative degradation of d-ribose in Haloarcula spp. This is the first characterization of an oxidative degradation pathway of d-ribose to α-ketoglutarate in archaea.Importance: The utilization and degradation of d-ribose in archaea, the third domain of life, have not been analyzed so far. We show that Haloarcula species utilize d-ribose, which is degraded to α-ketoglutarate via a novel oxidative pathway. Evidence is presented that the oxidative degradation of d-ribose involves novel promiscuous enzymes, pentose dehydrogenase and pentonolactonase, and a novel sugar acid dehydratase highly specific for ribonate. This is the first report of an oxidative degradation pathway of d-ribose in archaea, which differs from the canonical nonoxidative pathway of d-ribose degradation reported for most bacteria. The data contribute to our understanding of the unusual sugar degradation pathways and enzymes in archaea.Kadoya, S., Krissansen-Totton, J., Catling, D.C., 2020. Probable cold and alkaline surface environment of the Hadean Earth caused by impact ejecta weathering. Geochemistry, Geophysics, Geosystems 21, e2019GC008734.: Constraining the surface environment of the early Earth is essential for understanding the origin and evolution of life. The release of cations from silicate weathering depends on climatic temperature and pCO2, and such cations sequester into carbonate minerals in or on the seafloor, providing a stabilizing feedback on climate. Previous studies have suggested that this carbonate‐silicate cycle can keep the early Earth's surface temperature moderate by increasing pCO2 to compensate for the faint young Sun. However, the Hadean Earth experienced a high meteorite impactor flux, which produced ejecta that is easily weathered by carbonic acid. In this study, we estimated the histories of surface temperature and ocean pH during the Hadean and early Archean using a new model that includes the weathering of impact ejecta, empirically justified seafloor weathering, and ocean carbonate chemistry. We find that relatively low pCO2 and surface temperatures are probable during the Hadean, for example, at 4.3 Ga, (in bar) log10 (pCO2) is 2.21 +3.01 -2.54 and temperature is 259.2 +84.1-14.4 [2σ] K. Such a low would result in a circumneutral to basic pH of seawater, for example, 7.90 +1.21-1.69 [2σ] at 4.3 Ga. A probably cold and alkaline marine environment is associated with a high impact flux. Hence, if there was an interval of an enhanced impact flux, that is, Late Heavy Bombardment, similar conditions may have existed in the early Archean. Therefore, if the origin of life occurred in the Hadean, life likely emerged in a cold global environment and probably spread into an alkaline ocean.Plain Language Summary: The Earth's environment during the Hadean eon, 4.5 to 4 billion years ago, is obscured by a lack of geological evidence. However, life likely arose then, so improving our knowledge of the early environment is essential for understanding the origin and evolution of life. Here, we build a geological carbon cycle model that simulates the early surface environment and generates probability distributions for the level of atmospheric carbon dioxide (CO2), average surface temperature, and ocean pH over time. During the Hadean, CO2 dissolved in water is consumed by reacting with material ejected from meteorite impacts, so CO2 levels tend to be low and the greenhouse effect weak. The consequences are low surface temperature and alkaline seawater. The probability that the surface temperature was lower than the freezing point of water and that seawater pH exceeded 7 is 70% at 4.3 billion years ago. Thus, if life began in the Hadean, it likely emerged in a cold global environment, and early life may have spread into an alkaline ocean.Kalinowski, A.A., Gurba, L.W., 2020. Interpretation of vitrinite reflectance–depth profiles in the Northern Denison Trough, Bowen Basin, Australia. International Journal of Coal Geology 219, 103367. Denison Trough, Bowen Basin, Australia, is a mature hydrocarbon province that contains Permian to Triassic coal and gas bearing sediments deposited in deltaic to shallow marine shelf conditions. The sandstone reservoirs of the Permian Aldebaran Sandstone, Freitag Formation and Catherine Sandstone of the Northern Denison Trough (NDT) were evaluated for their CO2 storage potential as part of the Queensland Government’s ZeroGen CO2 Capture and Storage Project, which found that diagenetic processes acting on the sandstones have resulted in poor permeability and reduced porosity, making them unsuitable for large scale injection and storage in this area.To better understand the factors acting to degrade these reservoirs, the purpose of the current study was to establish a thermal maturity framework for the Permian sandstone reservoirs of the Northern Denison Trough based on vitrinite reflectance measurements of coals and Rock-Eval analysis of coals and shales from the Aldebaran Sandstone through to the Catherine Sandstone.Mean maximum vitrinite reflectance of coals (Rmax) ranges from 0.55% to 0.93%, and estimated maximum burial temperatures calculated from vitrinite reflectance fall between 83 oC – 125 oC. Calculation of palaeotemperatures from vitrinite reflectance data has been hampered by inversions of depth-reflectance profiles at the top of the Aldebaran Sandstone and scatter in vitrinite reflectance data. This has been attributed to depositional effects (including the major marine flooding surfaces at the top of the Aldebaran Sandstone) that have affected vitrinite reflectance evolution in the NDT, producing low reflecting, fluorescing, perhydrous vitrinite near marine flooding surfaces, and subhydrous vitrinite when oxidising conditions prevailed. A vitrinite reflectance difference of up to 0.2% Rmax is detected in an isometamorphic coal, an equivalent palaeotemperature difference of approximately 19 oC. The abundance of perhydrous vitrinite has resulted in largely suppressed vitrinite reflectance throughout the examined Permian interval in the Northern Denison Trough, and the presence of both perhydrous and subhydrous vitrinite introduces an error in palaeotemperature calculation in high volatile bituminous coals.Rock-Eval analysis provides supporting and calibrating maturity data. Tmax over the studied interval ranges from 421 oC to 447 oC, generating a positive, broadly linear correlation between Rmax and Tmax that is applicable specifically to the NDT. Tmax suppression was also detected in perhydrous coals. Hydrogen index serves to evaluate the level of vitrinite reflectance suppression through an inverse relationship between the two parameters. The Rock-Eval data confirms the oil generation potential of coals in the NDT while shales associated with the same stratigraphic intervals have lower hydrocarbon generation potential.This study brings new insights into the thermal maturity framework in the NDT and highlights the importance of reliable vitrinite reflectance data for calculation of maximum burial temperatures, particularly in underexplored or frontier areas.Kang, S., Kim, J.-H., Ryu, J.-S., Shin, K.-H., 2020. Dual carbon isotope (δ13C and Δ14C) characterization of particulate organic carbon in the Geum and Seomjin estuaries, South Korea. Marine Pollution Bulletin 150, 110719. investigated the source, composition, and reactivity of particulate organic carbon (POC) in two contrasting Korean estuary systems, a closed estuary (Geum) (i.e., with an estuary dam at the river mouth) and an open (Seomjin) estuary. A dual isotope (δ13CPOC and Δ14CPOC) approach was applied to surface water samples collected along a salinity gradient in August 2016. Our results indicate that phytoplankton-derived POC was the main contributor to the total POC pool in the reservoir of the Geum estuary, while terrestrial-derived POC predominated the upper Seomjin estuary. A simple binary mixing model using Δ14CPOC revealed a higher modern POC contribution (87–90%) in the Geum estuary reservoir than that (77%) of the upper Seomjin estuary. Accordingly, it appears that an estuary dam can alter the source and reactivity of POC in a reservoir, which can be transferred to the adjacent coastal ecosystem.Kaplitz, A.S., Kresge, G.A., Selover, B., Horvat, L., Franklin, E.G., Godinho, J.M., Grinias, K.M., Foster, S.W., Davis, J.J., Grinias, J.P., 2020. High-throughput and ultrafast liquid chromatography. Analytical Chemistry 92, 67-84. scientists working in many sectors have long expressed the need for increasingly fast chromatographic separations. The pharmaceutical industry, for example, has a growing demand for high-throughput methodologies in order to accelerate the discovery and development of new chemical entities.(1) Analytical toxicology laboratories require fast, robust methods for routine analysis of many clinical and forensic samples.(2) In biomedical research, in-depth proteomic and metabolomic studies of complex biological systems will continue to advance with rapid separation-based techniques.(3) Progress in these areas and others has advanced in parallel with improvements to LC column technology, especially as it relates to smaller packing materials, over the past several decades.(4) Arguably the most impactful result of the steady reduction in the size of chromatographic stationary phase supports is faster LC, run at higher mobile phase velocities without the significant losses in efficiency that are observed on columns packed with larger diameter particles. Both the use of smaller particles and higher mobile phase velocities require higher pressures than achievable with traditional HPLC instruments (400 bar limit), which necessitated the development of ultrahigh pressure liquid chromatography (UHPLC) instrumentation (1000–1500 bar limit). It has been over 20 years since the first demonstration of capillary UHPLC(5?7) and over 15 years since the release of the first commercial UHPLC platform.(8) Since that time, there has been a sharp increase in the use of UHPLC for analytical separations, with continuing trends toward higher speed and higher performance. This review focuses on recent advances that have led to unprecedented increases in method throughput for LC separations, especially as they relate to new developments in instrumentation and column technologies. In general, the descriptions of “high-throughput” and “ultrafast” LC have been defined in the context and limits of enabling technologies and thus continue to evolve. Defining metrics can include individual sample analysis time, full method cycle time, and general daily productivity. Although many papers make claims to fall under the ultrafast/high-throughput regime, the focus in this review is on separations that span the time scale from subsecond to an upper range of 1–2 min. The main emphasis of this review is on work that has been conducted since early 2017, although some older results are discussed for context or significance to a specific topic. Chromatographic theory, as it relates to column and particle design for separations performed at very high mobile phase velocities, is described. In addition, the practical instrumentation and hardware requirements needed to achieve higher throughput for both analytical scale and microscale techniques are discussed. Finally, specific modes of chromatography facilitating ultrafast separations and common application areas employing these techniques are detailed.Kato, K., Shinoda, T., Nagao, R., Akimoto, S., Suzuki, T., Dohmae, N., Chen, M., Allakhverdiev, S.I., Shen, J.-R., Akita, F., Miyazaki, N., Tomo, T., 2020. Structural basis for the adaptation and function of chlorophyll f in photosystem I. Nature Communications 11, 238. (Chl) play pivotal roles in energy capture, transfer and charge separation in photosynthesis. Among Chls functioning in oxygenic photosynthesis, Chl f is the most red-shifted type first found in a cyanobacterium Halomicronema hongdechloris. The location and function of Chl f in photosystems are not clear. Here we analyzed the high-resolution structures of photosystem I (PSI) core from H. hongdechloris grown under white or far-red light by cryo-electron microscopy. The structure showed that, far-red PSI binds 83 Chl a and 7 Chl f, and Chl f are associated at the periphery of PSI but not in the electron transfer chain. The appearance of Chl f is well correlated with the expression of PSI genes induced under far-red light. These results indicate that Chl f functions to harvest the far-red light and enhance uphill energy transfer, and changes in the gene sequences are essential for the binding of Chl f.Katsuta, N., Matsumoto, G.I., Hase, Y., Tayasu, I., Haraguchi, T.F., Tani, E., Shichi, K., Murakami, T., Naito, S., Nakagawa, M., Hasegawa, H., Kawakami, S.-i., 2019. Siberian permafrost thawing accelerated at the B?lling/Aller?d and Preboreal Warm periods during the last deglaciation. Geophysical Research Letters 46, 13961-13971. This study investigated a continuous sediment core, retrieved from the deepest part in Lake Hovsgol, northwestern Mongolia. Its surrounds are occupied by a continuous Siberian permafrost zone. Distinct geochemical and lithological features suggest that the watershed soil was moistened during the last deglaciation, associated with climate amelioration. Especially, the calcareous glacial clay layers (ca 13.7 and ca 11.0 cal. ka BP), with high sulfur content peaks and positive shifts of δ34S values, well correlate with the timing of meltwater pulses 1A and 1B, leading to rapid warming such as B?lling/Aller?d and Preboreal Holocene, respectively. This finding allows our interpretation for the calcareous glacial clay layers produced by landslide-induced debris flow, which resulted from intensive water discharge from rapid thawing of permafrost during the abrupt warming periods. Our correlation with Lake Baikal records suggests that these permafrost thawings have accelerated over the area of the Selenga drainage basin (continental interior Eurasia).Kelso, J.E., Baker, M.A., 2020. Organic matter is a mixture of terrestrial, autochthonous, and wastewater effluent in an urban river. Frontiers in Environmental Science 7, 202. doi: 10.3389/fenvs.2019. 00202.. 00202Terrestrially derived organic matter (OM) is known to dominate the OM pool in reference watersheds. Urban watersheds are known to receive large OM loads compared to reference watersheds, but the proportion of terrestrial, autochthonous, and anthropogenic (e.g., wastewater effluent) sources of OM in urban watersheds remains unknown. Organic matter was identified as a pollutant of concern in the Jordan River, an urban river in the Salt Lake Basin, U.S.A. Our objective was to identify autochthonous, terrestrial, and anthropogenic sources of three size-classes of OM to the Jordan River to inform OM reduction strategies within the watershed. Samples of coarse particulate OM (CPOM), fine particulate OM (FPOM), and dissolved OM (DOM) were analyzed for stable isotopes of carbon, nitrogen, and hydrogen. Stable isotope values of OM were used for Bayesian and graphical gradient-based mixing models to identify autochthonous, terrestrial, and anthropogenic sources. Fluorescent properties of DOM were also used to characterize the sources and composition of DOM. CPOM was primarily terrestrially derived with increased autochthonous inputs from macrophytes in warm months. FPOM was a mixture of terrestrial, autochthonous, and wastewater effluent throughout the year. DOM was primarily from wastewater effluent as well as DOM with isotope signatures unique to DOM from Utah Lake. Characterization of OM in urban rivers will help inform conceptual models of OM dynamics and load management in urban ecosystems.Khan, I., Zhong, N., Luo, Q., Ai, J., Yao, L., Luo, P., 2020. Maceral composition and origin of organic matter input in Neoproterozoic–Lower Cambrian organic-rich shales of Salt Range Formation, upper Indus Basin, Pakistan. International Journal of Coal Geology 217, 103319. appropriate thermal maturity (oil window or lower) of the Neoproterozoic rocks is a prerequisite for preserving robust and primary biological assemblages. The Neoproterozoic–Lower Cambrian organic-rich shales present in the upper part of Salt Range Formation, Pakistan, with abundant organic matter (OM) (total organic carbon (TOC) up to 46%) at relatively low thermal maturity (protobitumen reflectance, BRo?=?0.2–0.4%), represents by far the lowest-thermal maturity Neoproterozoic–Lower Cambrian rocks analyzed to date. The detailed petrographic description of Neoproterozoic–Lower Cambrian organic matter in the current study was lacking from previous source-rock studies of coeval strata from Oman, Eastern Siberia, Australia, and elsewhere. Eight organic-rich shales of the Salt Range Formation from three different outcrops have been analyzed for maceral composition and source rock characterization using organic petrography, scanning electron microscopy and standard source rock assessment techniques. The organic petrography reveals the organic-rich shales are predominantly composed of alginites (lamalginite and telalginite), bituminite, protobitumen, and mineral-bituminous groundmass. Overall, the maceral assemblages suggest the deposition of these shales took place under a salinity-stratified water-column in a shallow restricted basin, where both oxygenic and anoxygenic modes of primary production were operative. The top oxygenated part of the water-column was populated with the phototropic mat-forming cyanobacterium, whereas the lower, low-dissolved oxygen zone was dominated by algal mats and sulphate reduction bacteria. The rare and scattered thucholites present within the Salt Range Formation shales were derived from the radiation-induced polymerization of adjacent OM by the radioactive grains. The heat from the radioactive grains, however, found to have a negligible effect on the overall thermal maturity of these shales.Kim, J., Chhetri, G., Kim, I., Kim, M.K., Seo, T., 2020. Methylobacterium durans sp. nov., a radiation-resistant bacterium isolated from gamma ray-irradiated soil. Antonie van Leeuwenhoek 113, 211-220. gamma radiation-resistant, Gram-stain negative, oxidase and catalase positive, aerobic, flagellated, rod-shaped, methylotrophic and pink-pigmented bacterial strain designated 17SD2-17 T was isolated from gamma-ray-irradiated soil collected in Korea. The 16S rRNA gene sequence analysis showed that strain 17SD2-17 T is phylogenetically related to Methylobacterium organophilum DSM 760 T (97.6%), Methylobacterium oxalidis 35aT (97.4%) and Methylobacterium soli YIM 48816 T (97.0%). The G+C content calculated based on the draft genome sequence is 68.7 mol%. The DNA–DNA hybridisation between 17SD2-17 T and its close relatives was found to be less than 40%. The predominant fatty acid was identified as summed feature 8 (C18:1ω7c and/or C18:1ω6c) and the major respiratory quinone as Q-10. The major polar lipids were found to be diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. On the basis of the data from phenotypic tests and genotypic differences between strain 17SD2-17 T and its close phylogenetic relatives, strain 17SD2-17 T is concluded to represent a new species belonging to the genus Methylobacterium, for which the name Methylobacterium durans sp. nov. (=?KCTC 52908 T?=?NBRC 112876 T) is proposed.King, S.D., 2020. Do impacts impact global tectonics? Geology 48, 205-206. calculations have become an important hypothesis-testing tool when combined with the Precambrian geological record (c.f., van Hunen and Moyen, 2012: O’Neill et al., 2018; Stern and Gerya, 2018). These models are based on basic laws of physics, including the conservation of mass and energy, as well as Newton’s second law, sometimes misleadingly described as the conservation of momentum. To reduce the number of variables and create a set of equations that can be solved, a set of constitutive equations are required. For mantle convection, stress and strain rate are related through the viscosity. The viscosity of silicate minerals depends on temperature, pressure, composition, stress, grain size, water content, and history (c.f., King, 2016). Our understanding of viscosity is limited, in part due to the challenge of measuring the viscosity of silicate minerals at high pressures and temperatures, and the reality that the strain-rates achievable in such laboratory measurements must be extrapolated by orders of magnitude to mantle conditions. Geodynamic calculations are built upon solid physical principles; the calculations are limited in so far as our understanding of mantle viscosity is limited, and the appropriateness of the initial and boundary condition choices.Plate tectonics is the framework through which we understand the large-scale Phanerozoic history of Earth. The question of when and how plate tectonics began remains the subject of debate, in no small part because through subduction, plate tectonics destroys much of the evidence of its earlier activity. Estimates of the onset of plate tectonics vary from the Hadean (Hopkins et al., 2008), to the Archean (Brown, 2006), to the Neoproterozoic (Stern 2005, 2008). There is no rock record from the Hadean, and only a limited rock record from the Archean. Thus, it is unlikely that we will determine whether any deformation recorded during this time period was part of a globally connected plate boundary system or a regional, transient event.Spherule beds are preserved within Archean age rocks in the Barberton greenstone belt, South Africa (Lowe and Byerly, 1986; Lowe et al., 1989) and the Pilbara craton, Australia (Glikson et al., 2016). Archean spherule beds formed from the distal ejecta of large bolide impacts. These beds contain important clues regarding their formation—the thickness of the beds can be used to estimate the size of the impactor (Johnson and Melosh, 2012). Lowe et al. (2014) described four additional spherule beds and placed their formation at the same time as the first major episode of orogeny and crustal deformation in the Barberton greenstone belt (3.26–3.23 Ga). Lowe et al. further suggested that these impacts may have been the trigger that initiated the modern plate tectonic regime. A new contribution by O’Neill et al. (2020, page 174 in this issue) uses the characteristics of these recently described spherule beds to constrain the size and velocity of the impactors that formed them, extending the Archean impact record. They then use the Archean impact record as input to geodynamic models to test Lowe et al.’s hypothesis that these impacts could have initiated a modern style of plate tectonics.Lowe et al. (2014) were not the first to postulate that the Archean greenstone belts record plate tectonic activity. There are multiple lines of evidence that plate tectonics may have been operating in the Archean, including apparent polar wander curves (O’Neill et al., 2007), felsic volcanism consistent with melting of a water-rich source, and isotopic systematics similar to modern-day arcs (Hugh Smithies et al., 2018; O’Neill et al., 2018). The absence of clearly identified fold-and-thrust belts, tectonic mélanges, or ophiolites in the Archaean rock record casts doubts on the subduction interpretation (e.g., Stern, 2005; Moyen and van Hunen, 2012).Geodynamic calculations have become an important hypothesis-testing tool when combined with the Precambrian geological record (c.f., van Hunen and Moyen, 2012: O’Neill et al., 2018; Stern and Gerya, 2018). These models are based on basic laws of physics, including the conservation of mass and energy, as well as Newton’s second law, sometimes misleadingly described as the conservation of momentum. To reduce the number of variables and create a set of equations that can be solved, a set of constitutive equations are required. For mantle convection, stress and strain rate are related through the viscosity. The viscosity of silicate minerals depends on temperature, pressure, composition, stress, grain size, water content, and history (c.f., King, 2016). Our understanding of viscosity is limited, in part due to the challenge of measuring the viscosity of silicate minerals at high pressures and temperatures, and the reality that the strain-rates achievable in such laboratory measurements must be extrapolated by orders of magnitude to mantle conditions. Geodynamic calculations are built upon solid physical principles; the calculations are limited in so far as our understanding of mantle viscosity is limited, and the appropriateness of the initial and boundary condition choices.Several modes of surface behavior are recognized in geodynamic models. In stagnant-lid convection, the lithosphere is immobile with surface heat flow limited by conduction. In mobile-lid convection, the lithosphere is part of the convecting system, cooling as it advects along the surface, and sinking back into the warmer mantle. All other factors being equal, a stagnant-lid planet will have a hotter mantle than a mobile-lid planet. The transition from stagnant-lid to mobile-lid tectonics in geodynamic modeling has enriched our understanding of plate tectonics on Earth. As the mantle becomes hotter than at present day, many models show that plate-like behavior becomes episodic, with alternating periods of mobile-lid and stagnant-lid behavior (c.f., van Hunen and Moyen, 2012). An implication of these models is that evidence for plate tectonics may appear and disappear in the geological record, and subduction may repeatedly fail (O’Neill et al., 2018).The primary force driving plate tectonics is the negative buoyancy in subducted slabs (Forsyth and Uyeda, 1975). It is unclear what additional processes could produce the large forces necessary to initiate subduction on a pre–plate tectonic planet. To identify and test candidate processes, researchers have modeled the arrival of large plumes under the lithosphere (Gerya et al., 2015), magmatic weakening and volcanic loading (Moore and Webb, 2013; Nakagawa and Tackley, 2014), and bolide impacts (O’Neill et al., 2017). In many cases, subduction is transient, with the mantle reverting to a stagnant-lid state after a relatively brief time interval.In a previous study, O’Neill et al. (2017) examined the effect of bolide impacts on a Hadean Earth, finding that the thermal anomalies produced by extremely large impacting bolides (>～700 km in diameter) induce mantle upwellings that are capable of driving transient subduction events. These transient events terminate because the hotter Hadean mantle had a lower viscosity than the present-day mantle, reducing the coupling between the mantle and lithosphere (O’Neill et al., 2007), and the higher temperatures weakened the core of the subducting slab, resulting in necking and breakoff that reduces the slab pull force on the plate (van Hunen and Moyen, 2012).The present O’Neill et al. study (2020) addresses whether the estimated size and frequency of Mesoarchean impacts could have initiated subduction, and whether these events could have developed into a globally connected plate boundary network that continued without interruption to the present. There are several significant differences between the Hadean and Archean environments that will directly impact the geodynamic modeling. The Archean mantle should be cooler than the Hadean mantle (c.f., Christensen, 1985) and there should be smaller, less-frequent bolide impacts in the Archean when compared to the Hadean (Bottke et al. 2012). Thus, it is not possible to rescale the results of O’Neill et al.’s (2017) Hadean Earth study to address impact-induced subduction in the Archean.The two studies by O’Neill et al. (2017, 2020) are among the first studies to model the role of bolide impacts on planet-wide tectonic behavior applied to Earth. Both studies concluded that, if initiated, subduction would be a transient event, lasting only tens of millions of years, and leaving open the question of when plate tectonics (as the globally connected plate boundary network that we recognize today) took hold. The O’Neill et al. (2017, 2020) results are at odds with the results of Foley et al. (2014). The reason for the discrepancy may be that O’Neill et al. used a yield-stress formulation while Foley et al. (2014) used a formulation where the plate boundaries are weakened by grain-size reduction (Bercovici and Ricard, 2014).Foley (2018) suggested that the difference between the two formulations is related to how they respond to changes in lithospheric stress. In yield-stress formulations, when the lithospheric stress decreases, the stress level at the boundaries may no longer exceed the yield stress, resulting in lithospheric stagnation. In contrast, when lithosphere stress drops with increasing mantle temperature or heat production rate, the deformational work, which drives grain-size reduction, increases. Thus, in grain-size reduction formulations, the ability to form weak plate boundaries is not impeded by early Earth thermal conditions. Both formulations are based on sound physical principles. Yet it is not clear how each method applies to the complex environment of subduction zones. Our understanding of subduction initiation is limited by our understanding of the process by which a stagnant lithosphere begins to deform.Some may wonder whether appealing to a bolide impact as a trigger for subduction initiation is truly necessary. It is clear from the other inner Solar System bodies (Mercury, Venus, Mars, and the Moon) that bolide impacts were a significant process in the inner Solar System during the Hadean and Archean (Bottke et al., 2012). Thus, bolide impacts played a significant role in the Hadean and Archean on Earth. Geodynamicists assumed that because Earth’s mantle is convecting well above the critical Rayleigh number, over the course of Earth history the initial state of the mantle will be long forgotten. Weller and Lenardic (2012) showed that models with identical parameters starting from different initial conditions may end up in different states (e.g., stagnant-lid versus mobile-lid convection). When and whether a planet exhibits plate tectonics are likely functions of the initial state and history of the planet.When plate tectonics began has a fundamental control on the thermal evolution of Earth, because planets lose heat more effectively with a mobile lid than a stagnant lid. Thus, the earlier plate tectonics began, the further Earth has cooled from its initial state. The hypothesis that plate tectonics is necessary to create the kind of stable surface environment necessary for a habitable planet is of interest to the exoplanet community (Kasting and Catling, 2003).Kite, E.S., Mischna, M.A., Gao, P., Yung, Y.L., Turbet, M., 2020. Methane release on Early Mars by atmospheric collapse and atmospheric reinflation. Planetary and Space Science 181, 104820. candidate explanation for Early Mars rivers is atmospheric warming due to surface release of H2 or CH4 gas. However, it remains unknown how much gas could be released in a single event. We model the CH4 release by one mechanism for rapid release of CH4 from clathrate. By modeling how CH4-clathrate release is affected by changes in Mars' obliquity and atmospheric composition, we find that a large fraction of total outgassing from CH4 clathrate occurs following Mars' first prolonged atmospheric collapse. This atmosphere-collapse-initiated CH4-release mechanism has three stages. (1) Rapid collapse of Early Mars’ carbon dioxide atmosphere initiates a slower shift of water ice from high ground to the poles. (2) Upon subsequent CO2-atmosphere re-inflation and CO2-greenhouse warming, low-latitude clathrate decomposes and releases methane gas. (3) Methane can then perturb atmospheric chemistry and surface temperature, until photochemical processes destroy the methane.Within our model, we find that under some circumstances a Titan-like haze layer would be expected to form, consistent with transient deposition of abundant complex abiotic organic matter on the Early Mars surface. We also find that this CH4-release mechanism can warm Early Mars, but special circumstances are required in order to uncork 1017?kg of CH4, the minimum needed for strong warming. Specifically, strong warming only occurs when the fraction of the hydrate stability zone that is initially occupied by clathrate exceeds 10%, and when Mars’ first prolonged atmospheric collapse occurs for atmospheric pressure >1?bar.Korf, A., Fouquet, T., Schmid, R., Hayen, H., Hagenhoff, S., 2020. Expanding the Kendrick mass plot toolbox in MZmine 2 to enable rapid polymer characterization in liquid chromatography?mass spectrometry data sets. Analytical Chemistry 92, 628-633. advances in mass spectrometry (MS) toward more accurate and faster data acquisition result in highly informative but also more complex data sets. Especially the hyphenation of liquid chromatography (LC) and MS yields large data files containing a high amount of compound specific information. Using electrospray-ionization for compounds such as polymers enables highly sensitive detection, yet results in very complex spectra, containing multiply charged ions and adducts. Recent years have seen the development of novel or updated data mining strategies to reduce the MS spectra complexity and to ultimately simplify the data analysis workflow. Among other techniques, the Kendrick mass defect analysis, which graphically highlights compounds containing a given repeating unit, has been revitalized with applications in multiple fields of study, such as lipids and polymers. Especially for the latter, various data mining concepts have been developed, which extend regular Kendrick mass defect analysis to multiply charged ion series. The aim of this work is to collect and subsequently implement these concepts in one of the most popular open-source MS data mining software, i.e., MZmine 2, to make them rapidly available for different MS based measurement techniques and various vendor formats, with a special focus on hyphenated techniques such as LC–MS. In combination with already existing data mining modules, an example data set was processed and simplified, enabling an ever faster evaluation and polymer characterization.Koshel, B., Birdsall, R., Chen, W., 2020. Two-dimensional liquid chromatography coupled to mass spectrometry for impurity analysis of dye-conjugated oligonucleotides. Journal of Chromatography B 1137, 121906. liquid chromatography coupled to mass spectrometry (2D-LC/MS) has been successfully implemented for several biopharmaceutical applications, but applications for oligonucleotide analysis have been relatively unexplored. When analyzing oligonucleotides in one-dimension, selecting an ion-pairing agent often requires a balance between acceptable chromatographic and mass spectrometric performance. When oligonucleotides are modified or conjugated to include extremely hydrophobic groups, such as fluorophores, the separation mechanism is further complicated by the impact the fluorophore has on retention. Triethylamine (TEA) buffered in hexafluoroisopropanol (HFIP) is the most commonly used ion-pairing agent for analyses requiring mass spectrometry, but the elution order of dye-conjugated failed sequences relative to the main peak is not length-based compared to what would be predicted for unconjugated oligonucleotides having the same sequence. Hexylammonium acetate (HAA) offers more efficient ion-pairing for a length-based separation, but MS response is compromised due to ion suppression. In this study, 2D-LC/MS is used to show that dye-conjugated oligonucleotide failed sequences can be resolved from the parent oligonucleotide using a strong ion-pairing agent in the first-dimension and further identified using a weaker but MS compatible ion-pairing agent in the second-dimension, results that are not achievable in a one-dimensional analysis. More specifically, a heart-cut configuration using ion-pair reversed-phase chromatography in both the first and second dimension (IP-RP – IP-RP) is used to transfer the n-1 impurity from a length-based separation in the first-dimension to a second-dimension analysis for identity confirmation using a single quadrupole detector. Identical C18 column chemistry is used in both the first and second dimension to exploit changes in selectivity that are due to mobile phase selection. The n-1 impurity from the two-dimensional analysis can be detected at low nanogram levels, comparable to results achieved in a one-dimensional dilution series, which approaches the limit of detection of the instrumentation. This work has future applicability to more complex impurity profiling using high-resolution instrumentation, where a more extensive set of impurities could not be evaluated using one-dimensional techniques.Kou, Y., Zhang, L., Fan, D., Cheng, S., Li, D., Hodel, R.G.J., Zhang, Z., 2019. Evolutionary history of a relict conifer, Pseudotaxus chienii (Taxaceae), in south-east China during the late Neogene: old lineage, young populations. Annals of Botany 125, 105-117. and Aims:Many monotypic gymnosperm lineages in south-east China paradoxically remain in relict status despite long evolutionary histories and ample opportunities for allopatric speciation, but this paradox has received little attention and has yet to be resolved. Here, we address this issue by investigating the evolutionary history of a relict conifer, Pseudotaxus chienii (Taxaceae).Methods:DNA sequences from two chloroplast regions and 14 nuclear loci were obtained for 134 samples. The demographic history was inferred and the contribution of isolation by environment (IBE) in patterning genetic divergence was compared with that of isolation by distance (IBD).Key ResultsThree genetic clusters were identified. Approximate Bayesian computation analyses showed that the three clusters diverged in the late Pliocene (~3.68 Ma) and two admixture events were detected. Asymmetric gene flow and similar population divergence times (~ 3.74 Ma) were characterized using the isolation with migration model. Neither IBD nor IBE contributed significantly to genetic divergence, and the contribution of IBE was much smaller than that of IBD.Conclusions:These results suggest that several monotypic relict gymnosperm lineages like P. chienii in south-east China did not remain in situ and undiversified for millions of years. On the contrary, they have been evolving and the extant populations have become established more recently, having insufficient time to speciate. Our findings provide a new perspective for understanding the formation and evolution of the relict gymnosperm flora of China as well as of the Sino-Japanese Flora.Krause, J.W., Lomas, M.W., 2020. Understanding diatoms’ past and future biogeochemical role in high-latitude seas. Geophysical Research Letters 47, e2019GL085602.: Because cold‐water diatoms’ baseline elemental density (BED) is substantially higher than temperate diatoms, previous polar studies may have underestimated diatoms’ contribution to elemental standing stocks, contribution to particulate organic carbon (POC) export and incorrectly modeled their susceptibility to future warming. We apply cold‐water diatom allometry to Arctic field samples and derive diatom growth rates ranging from 0.01–0.68 day?1, versus unrealistically high rates estimated using temperate diatom allometry. Reanalysis of published Southern Ocean data (Antarctic Environment and Southern Ocean Process Study and European Iron Fertilization Experiment) shows that diatom POC was significantly underestimated and diatoms could have accounted for a majority of POC export. However, during some field programs (Kerguelen Plateau), temperate allometry properly accounted for diatom biomass. We also predict that warming sea surface temperature may alter high‐latitude diatom BED, suggesting that even if abundances do not change with warming, the reduced diatom BED will likely lower the trophic‐transfer efficiency and their total carbon flow to consumers.Plain Language Summary: High‐latitude marine regions are warming faster than other marine systems. We show that the role of diatoms in these systems, already thought to be important, was systematically underestimated in some studies due to insufficient understanding of cold‐water diatoms’ physiology, specifically their high elemental density. When applying cold‐water‐diatom elemental density relationships to original and previously published high‐latitude field data, diatom growth rates were rapid (up to a doubling per day), and they could account for most of the organic carbon standing stock and its export—original publications inferred contributions <20%. We predict that cold‐water diatom elemental density will decline with increasing warming. Such a decline in diatom food quality (less element per volume), even without diatom abundance declines, may reduce transfer of their material to consumers and affect food webs.Kreling, N.E., Zaparoli, M., Margarites, A.C., Friedrich, M.T., Thomé, A., Colla, L.M., 2020. Extracellular biosurfactants from yeast and soil–biodiesel interactions during bioremediation. International Journal of Environmental Science and Technology 17, 395-408. aim of this study was to select cultivation conditions for the production of extracellular biosurfactants from Saccharomyces cerevisiae. This yeast has been recognized due to the production of intracellular biosurfactants, and this work presented a technique to produce extracellular biosurfactants, allowing the reduction in costs with downstream processes. We studied the scale up of production in bioreactors and their effects on bioremediation in soils contaminated with biodiesel. Furthermore, we also evaluated the effects of biosurfactant addition on the adsorption of contaminants in these soils. The concentration and types of inducer (glycerol, soybean oil and diesel oil), pH levels and temperatures were studied to maximize the production through factorial designs. The results that obtained the maximum emulsifying production (6.95 UE d?1) were found in the concentration of 5 g L?1 of glycerol, a pH 5.5 and a temperature of 30 °C. In the scale up of the 5 L bioreactor, the maximum productivity of 3.85 UE d?1 was achieved in 2 days. The addition of 0.05%, 0.1% and 0.5% of biosurfactant in soil contaminated with 20% of biodiesel for 90 days allowed a biodegradation of 56.71% with a 0.5% of biosurfactant. For all evaluated conditions, 25% of the biodegradation value should actually be attributed to the adsorption process. The addition of biosurfactants does not affect the retention of the contaminant in the soil, demonstrating that the biosurfactants improved biodegradation without interfering in the adsorption process of the contaminant in the selected soil, which is important in order to avoid influencing the movement processes of contamination plumes.Kuhry, P., Bárta, J., Blok, D., Elberling, B., Faucherre, S., Hugelius, G., J?rgensen, C.J., Richter, A., ?antr??ková, H., Weiss, N., 2020. Lability classification of soil organic matter in the northern permafrost region. Biogeosciences 17, 361-379. large stocks of soil organic carbon (SOC) in soils and deposits of the northern permafrost region are sensitive to global warming and permafrost thawing. The potential release of this carbon (C) as greenhouse gases to the atmosphere does not only depend on the total quantity of soil organic matter (SOM) affected by warming and thawing, but it also depends on its lability (i.e., the rate at which it will decay). In this study we develop a simple and robust classification scheme of SOM lability for the main types of soils and deposits in the northern permafrost region. The classification is based on widely available soil geochemical parameters and landscape unit classes, which makes it useful for upscaling to the entire northern permafrost region. We have analyzed the relationship between C content and C-CO2 production rates of soil samples in two different types of laboratory incubation experiments. In one experiment, ca. 240 soil samples from four study areas were incubated using the same protocol (at 5?°C, aerobically) over a period of 1 year. Here we present C release rates measured on day 343 of incubation. These long-term results are compared to those obtained from short-term incubations of ca. 1000 samples (at 12?°C, aerobically) from an additional three study areas. In these experiments, C-CO2 production rates were measured over the first 4?d of incubation. We have focused our analyses on the relationship between C-CO2 production per gram dry weight per day (?gC-CO2?gdw?1?d?1) and C content (%C of dry weight) in the samples, but we show that relationships are consistent when using C?∕?N ratios or different production units such as ?gC per gram soil C per day (?gC-CO2?gC?1?d?1) or per?cm3 of soil per day (?gC-CO2?cm?3?d?1). C content of the samples is positively correlated to C-CO2 production rates but explains less than 50?% of the observed variability when the full datasets are considered. A partitioning of the data into landscape units greatly reduces variance and provides consistent results between incubation experiments. These results indicate that relative SOM lability decreases in the order of Late Holocene eolian deposits to alluvial deposits and mineral soils (including peaty wetlands) to Pleistocene yedoma deposits to C-enriched pockets in cryoturbated soils to peat deposits. Thus, three of the most important SOC storage classes in the northern permafrost region (yedoma, cryoturbated soils and peatlands) show low relative SOM lability. Previous research has suggested that SOM in these pools is relatively undecomposed, and the reasons for the observed low rates of decomposition in our experiments need urgent attention if we want to better constrain the magnitude of the thawing permafrost carbon feedback on global warming.Kutchko, B., Sanguinito, S., Natesakhawat, S., Cvetic, P., Culp, J.T., Goodman, A., 2020. Quantifying pore scale and matrix interactions of SCCO2 with the Marcellus shale. Fuel 266, 116928. Shale was investigated as a storage reservoir for CO2, applying CO2 as an enhanced hydrocarbon recovery agent, and examining the CO2 alteration of the shale as a sealing unit. The investigation was comprised of observing the geochemical interaction of CO2 and water with two Marcellus Shale samples (MS-1 [silicate-rich] and MS-4 [carbonate-rich]) using various analytical techniques. In-situ Fourier Transform infrared (FT-IR) spectroscopy at geological storage conditions (high temperature and pressure) was used to examine the geochemical interaction of CO2 (with and without water) and Marcellus Shale. FT-IR results showed that CO2 interacted physically with the clay and kerogen components of dehydrated Marcellus Shale samples while dissolving in the water layer in the hydrated Marcellus Shale samples to promote carbonate dissolution. Feature relocation scanning electron microscopy was utilized to document the physical changes and the pore alterations based on exposure to CO2 with and without water. SEM indicated significant carbonate dissolution to the MS-4 sample after exposure to CO2 and water. Density function theory (DFT) and sorption isotherms were used for pore size analysis and to quantify CO2 sorption. The results were very different for the two Marcellus Shale samples studied. The MS-4 showed dissolution of carbonate to be a major reaction under hydrated conditions with a loss of mesopore volume from 68% to 40%, while MS-1 often showed an opposite trend. Both the MS-1 and MS-4 samples showed that significant volume of macropores larger than 200?nm were present. Isotherm results suggested uptake of CO2 of the MS-4 sample is four times greater than the MS-1 sample.Kwok, H., Yan, J., Brunswick, P., McMaster, M., Evans, M., Kim, M., Helbing, C., van Aggelen, G., Shang, D., 2020. Ultra trace simultaneous determination of 50 polycyclic aromatic hydrocarbons in biota using pMRM GC-MS/MS. Environmental Forensics 21, 87-98.. 1693443A saponification extraction method with gas chromatography pseudo-MRM (pMRM) mass spectrometry detection was developed for the determination of 50 total polycyclic aromatic hydrocarbons (TPAH50, a combination of parent and alkylated homologues) in biota. The method was aimed at monitoring and identification of potential TPAH contaminants in bitumen impacted environments. Alkylated PAHs were determined by multi-level, quantitative calibration using parent PAHs. The developed and thoroughly validated method required only one injection for TPAH50 analysis which represents significant saving of time and expensive authentic alkylated standards. The current method was tested with certified reference mussel tissue NIST 1974c and performed well. In a comparison study, the method reached a limit of quantitation (LOQ) for the TPAH50 between 0.1 and 0.2?ng g?1, while the QuEChERs enhanced matrix removal – lipid (EMR) kit produced by Agilent showed an LOQ of 5–10?ng g?1. The current method relied on response factors (RF) for the quantitation of alkylated PAHs determined against parent PAHs. These RFs were shown to be stable and consistent over the course of 1 year, during which over 200 routine environmental biota monitoring samples were analyzed. The environmental biota monitoring samples analyzed include muscle, carcass and liver, with an average total PAH50 concentration of 13, 90 and 135?ng g?1, respectively. Results show significant differences in the distributions of 1 ringed, 2 ringed, 3 ringed, 4 ringed, and 5+ ringed TPAHs between the types of biota samples.Ladant, J.-B., Poulsen, C.J., Fluteau, F., Tabor, C.R., MacLeod, K.G., Martin, E.E., Haynes, S.J., Rostami, M.A., 2020. Paleogeographic controls on the evolution of Late Cretaceous ocean circulation. Climate of the Past Discussions 2020, 1-65. of the role of ocean circulation on climate during the Late Cretaceous is contingent on the ability to reconstruct its modes and evolution. Geochemical proxies used to infer modes of past circulation provide conflicting interpretations for the reorganization of the ocean circulation through the Late Cretaceous. Here, we present climate model simulations of the Cenomanian (100.5–93.9?Ma) and Maastrichtian (72.1–66.1?Ma) stages of the Cretaceous with the CCSM4 earth system model. We focus on intermediate (500–1500?m) and deep (>?1500?m) ocean circulation, and show that while there is continuous deep-water production in the southwest Pacific, major circulation changes occur between the Cenomanian and Maastrichtian. Opening of the Atlantic and Southern Ocean, in particular, drives a transition from a mostly zonal circulation to enhanced meridional exchange. Using additional experiments to test the effect of deepening of major ocean gateways in the Maastrichtian, we demonstrate that the geometry of these gateways likely had a considerable impact on ocean circulation. We further compare simulated circulation results with compilations of εNd records and show that simulated changes in Late Cretaceous ocean circulation are reasonably consistent with inferences from this proxy. In our simulations, consistency with the geologic history of major ocean gateways and absence of shift in areas of deep-water formation suggest that the Late Cretaceous trend in εNd values in the Atlantic and southern Indian Oceans was caused by the subsidence of volcanic provinces and opening of the Atlantic and Southern Oceans rather than changes in deep-water formation areas and/or reversal of deep-water fluxes. However, the complexity in interpreting Late Cretaceous εNd values underscores the need for new records as well as specific εNd modeling to better discriminate between the various plausible theories of ocean circulation change during this period.Lai, Y.-W., Ridone, P., Peralta, G., Tanaka, M.M., Baker, M.A.B., 2020. Evolution of the stator elements of rotary prokaryote motors. Journal of Bacteriology 202, e00557-19. bacterial flagellar motor is driven by an ion flux that is converted to torque by motor-attendant complexes known as stators. The dynamics of stator assembly around the motor in response to external stimuli have been the subject of much recent research, but less is known about the evolutionary origins of stator complexes and how they select for specific ions. Here, we review the latest structural and biochemical data for the stator complexes and compare these with other ion transporters and microbial motors to examine possible evolutionary origins of the stator complex.Lam, B.R., Barge, L.M., Noell, A.C., Nealson, K.H., 2019. Detecting endogenous microbial metabolism and differentiating between abiotic and biotic signals observed by bioelectrochemical systems in soils. Astrobiology 20, 39-52. detection of chemical and physical signatures of microbial life on Mars or other solar system bodies requires differentiation between signals produced by biotic and abiotic processes; instruments aimed at generalized in situ extant life detection would therefore increase the science return of a life-detection mission. Here, we investigate Bioelectrochemical Systems (BES) as a technique to measure microbial metabolism (which produces electrical current and redox changes) and distinguish between potential abiotic and biotic responses in environmental samples. Samples from inhabited niches should contain everything necessary to produce current, that is, catalysts (microorganisms) and fuel (nutrients). BES can also probe for inactive organisms in less energetically rich areas by adding a fuel to drive metabolism. A commercial potting soil and a Mars simulant soil were inoculated in the anodic chamber of microbial fuel cells, and current was monitored over time. Addition of a fuel (electron donor) source was tested for metabolic stimulation of endogenous microbes. Redox reactions between Mars simulant soil and the introduced electron donor (lactate) produced false-positive results, emphasizing the importance of careful interpretation of signals obtained. The addition of lactate to both soils resulted in enhanced biologically produced current, allowing stimulation and detection of dormant microbes. Our results demonstrate that BES provide an approach to detect metabolism in samples without prior knowledge of the organisms present, and that thorough electrochemical analyses and experimental design are necessary to determine if signals are biotic.Lang, S.Q., Brazelton, W.J., 2020. Habitability of the marine serpentinite subsurface: a case?study of the Lost City hydrothermal field. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20180429. Lost City hydrothermal field is a dramatic example of the biological potential of serpentinization. Microbial life is prevalent throughout the Lost City chimneys, powered by the hydrogen gas and organic molecules produced by serpentinization and its associated geochemical reactions. Microbial life in the serpentinite subsurface below the Lost City chimneys, however, is unlikely to be as dense or active. The marine serpentinite subsurface poses serious challenges for microbial activity, including low porosities, the combination of stressors of elevated temperature, high pH and a lack of bioavailable ∑CO2. A better understanding of the biological opportunities and challenges in serpentinizing systems would provide important insights into the total habitable volume of Earth's crust and for the potential of the origin and persistence of life in Earth's subsurface environments. Furthermore, the limitations to life in serpentinizing subsurface environments on Earth have significant implications for the habitability of subsurface environments on ocean worlds such as Europa and Enceladus. Here, we review the requirements and limitations of life in serpentinizing systems, informed by our research at the Lost City and the underwater mountain on which it resides, the Atlantis Massif.Langer, J., Jimenez de Aberasturi, D., Aizpurua, J., Alvarez-Puebla, R.A., Auguié, B., Baumberg, J.J., Bazan, G.C., Bell, S.E.J., Boisen, A., Brolo, A.G., Choo, J., Cialla-May, D., Deckert, V., Fabris, L., Faulds, K., García de Abajo, F.J., Goodacre, R., Graham, D., Haes, A.J., Haynes, C.L., Huck, C., Itoh, T., K?ll, M., Kneipp, J., Kotov, N.A., Kuang, H., Le Ru, E.C., Lee, H.K., Li, J.-F., Ling, X.Y., Maier, S.A., Mayerh?fer, T., Moskovits, M., Murakoshi, K., Nam, J.-M., Nie, S., Ozaki, Y., Pastoriza-Santos, I., Perez-Juste, J., Popp, J., Pucci, A., Reich, S., Ren, B., Schatz, G.C., Shegai, T., Schlücker, S., Tay, L.-L., Thomas, K.G., Tian, Z.-Q., Van Duyne, R.P., Vo-Dinh, T., Wang, Y., Willets, K.A., Xu, C., Xu, H., Xu, Y., Yamamoto, Y.S., Zhao, B., Liz-Marzán, L.M., 2020. Present and future of surface-enhanced Raman scattering. ACS Nano 14, 28-117. discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article.Larson, B.T., Ruiz-Herrero, T., Lee, S., Kumar, S., Mahadevan, L., King, N., 2020. Biophysical principles of choanoflagellate self-organization. Proceedings of the National Academy of Sciences 117, 1303-1311.: Comparisons among animals and their closest living relatives, the choanoflagellates, have begun to shed light on the origin of animal multicellularity and development. Here, we complement previous genetic perspectives on this process by focusing on the biophysical principles underlying choanoflagellate colony morphology and morphogenesis. Our study reveals the crucial role of the extracellular matrix in shaping the colonies and leads to a phase diagram that delineates the range of morphologies as a function of the biophysical mechanisms at play.Abstract: Inspired by the patterns of multicellularity in choanoflagellates, the closest living relatives of animals, we quantify the biophysical processes underlying the morphogenesis of rosette colonies in the choanoflagellate Salpingoeca rosetta. We find that rosettes reproducibly transition from an early stage of 2-dimensional (2D) growth to a later stage of 3D growth, despite the underlying variability of the cell lineages. Our perturbative experiments demonstrate the fundamental importance of a basally secreted extracellular matrix (ECM) for rosette morphogenesis and show that the interaction of the ECM with cells in the colony physically constrains the packing of proliferating cells and, thus, controls colony shape. Simulations of a biophysically inspired model that accounts for the size and shape of the individual cells, the fraction of ECM, and its stiffness relative to that of the cells suffices to explain our observations and yields a morphospace consistent with observations across a range of multicellular choanoflagellate colonies. Overall, our biophysical perspective on rosette development complements previous genetic perspectives and, thus, helps illuminate the interplay between cell biology and physics in regulating morphogenesis.Laugié, M., Donnadieu, Y., Ladant, J.-B., Green, M., Bopp, L., Raisson, F., 2020. Stripping back the Modern to reveal Cretaceous climate and temperature gradient underneath. Climate of the Past Discussions 2020, 1-39. past geological times, the Earth suffered several intervals of global warmth but their driving factors remain equivocal. A careful appraisal of the main processes involved in those past events is essential to evaluate how they can inform future climates, and thus to provide decision makers with a clear understanding of the processes at play in a warmer world. In this context, the greenhouse Earth of the Cretaceous era, specifically the Cenomanian-Turonian (~?94?Ma), is of particular interest, as it corresponds to a thermal maximum. Here we use the IPSL-CM5A2 Earth System Model to unravel the forcing parameters of the Cenomanian-Turonian greenhouse climate. We perform six simulations with an incremental change in five major boundary conditions in order to isolate their respective role on climate change between the Cretaceous and the preindustrial. Starting with a preindustrial simulation, we implement: (1) the absence of polar ice sheets, (2) the increase in atmospheric pCO2 to 1120?ppm, (3) the change of vegetation and soil parameters, (4) the 1?% decrease in the Cenomanian-Turonian value of the solar constant and (5) the Cenomanian-Turonian paleogeography. Between the first (preindustrial) simulation and the last (Cretaceous) simulation, the model simulates a global warming of more than 11?°C. Most of this warming is driven by the increase in atmospheric pCO2 to 1120?ppm. Paleogeographic changes represent the second major contributor to the global warming while the reduction in the solar constant counteracts most of the geographically-driven global warming. We also demonstrate that the implementation of Cretaceous boundary conditions flattens the temperature gradients compared to the piControl simulation. Interestingly, we show that paleogeography is the major driver of the flattening in the low- to mid-latitudes whereas the pCO2 rise and polar ice sheet retreat dominate the high-latitudes response.Le, T., ?ársk?, V., N?vltová, E., Rada, P., Harant, K., Vancová, M., Verner, Z., Hrd?, I., Tachezy, J., 2020. Anaerobic peroxisomes in Mastigamoeba balamuthi. Proceedings of the National Academy of Sciences 117, 2065-2075.: It is generally accepted that peroxisomes are absent in anaerobic eukaryotes. These organelles have evolved to compartmentalize oxidative pathways and prevent cellular oxidative damage, namely, the β-oxidation of fatty acids that utilizes molecular oxygen and produces hydrogen peroxide. Mitochondria possess a parallel β-oxidation pathway coupled with the respiratory chain. The adaptation of eukaryotes to anaerobiosis is reflected by the reduction of mitochondrial metabolism and, not surprisingly, concomitant loss of peroxisomes. The free-living anaerobic protist Mastigamoeba balamuthi is an organism that contradicts this paradigm. Although Mastigamoeba possesses hydrogenosomes, an anaerobic form of mitochondria, it also harbors peroxisomes. These organelles contain the archetypical Pexs that are required for peroxisomal biogenesis; however, they lack the hallmarks of peroxisomal metabolism, β-oxidation and catalase.Abstract: The adaptation of eukaryotic cells to anaerobic conditions is reflected by substantial changes to mitochondrial metabolism and functional reduction. Hydrogenosomes belong among the most modified mitochondrial derivative and generate molecular hydrogen concomitant with ATP synthesis. The reduction of mitochondria is frequently associated with loss of peroxisomes, which compartmentalize pathways that generate reactive oxygen species (ROS) and thus protect against cellular damage. The biogenesis and function of peroxisomes are tightly coupled with mitochondria. These organelles share fission machinery components, oxidative metabolism pathways, ROS scavenging activities, and some metabolites. The loss of peroxisomes in eukaryotes with reduced mitochondria is thus not unexpected. Surprisingly, we identified peroxisomes in the anaerobic, hydrogenosome-bearing protist Mastigamoeba balamuthi. We found a conserved set of peroxin (Pex) proteins that are required for protein import, peroxisomal growth, and division. Key membrane-associated Pexs (MbPex3, MbPex11, and MbPex14) were visualized in numerous vesicles distinct from hydrogenosomes, the endoplasmic reticulum (ER), and Golgi complex. Proteomic analysis of cellular fractions and prediction of peroxisomal targeting signals (PTS1/PTS2) identified 51 putative peroxisomal matrix proteins. Expression of selected proteins in Saccharomyces cerevisiae revealed specific targeting to peroxisomes. The matrix proteins identified included components of acyl-CoA and carbohydrate metabolism and pyrimidine and CoA biosynthesis, whereas no components related to either β-oxidation or catalase were present. In conclusion, we identified a subclass of peroxisomes, named “anaerobic” peroxisomes that shift the current paradigm and turn attention to the reductive evolution of peroxisomes in anaerobic organisms.Lee, J.E., Edwards, J.S., Schmitt, J., Fischer, H., Bock, M., Brook, E.J., 2020. Excess methane in Greenland ice cores associated with high dust concentrations. Geochimica et Cosmochimica Acta 270, 409-430. core records of atmospheric methane (CH4) and its isotopic composition provide important information about biogeochemical cycles in the past. Interpreting these data requires that they faithfully record the composition of the atmosphere. In this study, we describe anomalies of up to 30–40?ppb CH4 that are only observed in dust-rich (>～60?ng Ca/g ice), glacial-period ice measured with standard melt-refreeze methods. The stable isotopic composition of CH4 is also significantly affected. Results from the GISP2 and NEEM ice cores from Greenland show that excess CH4 is either released or produced in the presence of liquid water in amounts which are highly correlated with the abundance of Ca2+ and mineral dust in the sample. Additional experiments show that excess CH4 is unaffected by the addition of HgCl2 (a microbial inhibitor) and is not related to ice core storage time. Dust concentrations in Antarctic ice cores are an order of magnitude lower than in Greenlandic ice cores and no excess CH4 was observed in samples from the Antarctic WAIS Divide (WD) and South Pole (SPICE) ice cores. While the overall structure of the ice core atmospheric methane history is minimally impacted by excess CH4, the impacts on the isotopic record and on inverse models used to reconstruct CH4 sources are greater. We propose three potential mechanisms to explain the presence of excess CH4: (1) that CH4 is adsorbed on dust particles prior to deposition on the ice sheet and is slowly desorbed during the melt-extraction step of sample analysis; (2) that dust acts as a micro-environment within the ice sheet for methanogenic extremophiles; or (3) that excess CH4 is a product of abiotic degradation of organic compounds during the melt-extraction step of sample analysis.Lee, K.J., 2020. Characterization of kerogen content and activation energy of decomposition using machine learning technologies in combination with numerical simulations of formation heating. Journal of Petroleum Science and Engineering 188, 106860. estimation of organic matter characteristics is essential in source and reservoir rocks evaluation. Their measurement is generally based on well logging and experiments after core sampling. In this study, we present a different approach from these methods to evaluate the characteristics of organic matter, which is based on the numerical simulations in combination with machine learning technologies.Formation heating processes of organic-rich shales and in-situ pyrolysis of kerogen are numerically simulated, where the time-series data of heater temperature are monitored. Here, we consider the whole organic matter composed with kerogen. The monitored heater temperature data are used as an input of inverse modeling by Artificial Neural Network (ANN) and Support Vector Machines (SVM) to figure out the characteristics of kerogen. Heater temperature acts as an indicator of type and maturity of kerogen, since it is affected by the bulk thermal conductivity of formation, which is a function of dynamically changing rock-and-pore composition by kerogen decomposition.We simulate the processes of electrical heating of 300 different formations, containing either one of Type 1, 2, or 3 kerogen with various amounts and activation energies. ANN method is employed to generate a data-driven model to estimate the unknown kerogen content and activation energy using heater temperature as an input data. SVM method, which categorizes dataset into the multiple classes by using hyperplanes, is applied to classify the dataset of heater temperature into different types of kerogens. Developed ANN and SVM models show great performances in the inversion and classification.The suggested characterization method provides a simple tool of estimating reactivity and type of kerogens. It will be used as a proxy for the inverse modeling of geochemical characterization of organic matter coupled with forward numerical simulations, by reducing the number of simulation runs required in the traditional inverse modeling.Lee, S.-A., Kim, T.-H., Kim, G., 2020. Tracing terrestrial versus marine sources of dissolved organic carbon in a coastal bay using stable carbon isotopes. Biogeosciences 17, 135-144. sources of dissolved organic matter (DOM) in coastal waters are diverse, and they play different roles in the biogeochemistry and ecosystems of the ocean. In this study, we measured dissolved organic carbon (DOC) and nitrogen (DON), the stable carbon isotopic composition of dissolved organic carbon (δ13C-DOC), and fluorescent dissolved organic matter (FDOM) in coastal bay waters surrounded by large cities (Masan Bay, Republic of Korea) to determine the different DOM sources in this region. The surface seawater samples were collected in two sampling campaigns (August 2011 and August 2016). The salinities were in the range of 10–21 in 2011 and 25–32 in 2016. In 2011, excess DOC was observed in high-salinity (16–21) waters; the excess DOC source was found to be mainly from marine autochthonous production according to the δ13C-DOC values (?23.7?‰ to ?20.6?‰), the higher concentrations of protein-like FDOM, and the lower DOC∕DON (C∕N) ratios (8–15). In contrast, excess DOC observed in high-salinity waters in 2016 was characterized by low FDOM, more depleted δ13C values (?28.8?‰ to ?21.1?‰), and high C∕N ratios (13–45), suggesting that the source of excess DOC is terrestrial C3 plants by direct land–seawater interactions. Our results show that multiple DOM tracers such as δ13C-DOC, FDOM, and C∕N ratios are powerful for determining different sources of DOM occurring in coastal waters.Lehmer, O.R., Catling, D.C., Buick, R., Brownlee, D.E., Newport, S., 2020. Atmospheric CO2 levels from 2.7 billion years ago inferred from micrometeorite oxidation. Science Advances 6, eaay4644.’s atmospheric composition during the Archean eon of 4 to 2.5 billion years ago has few constraints. However, the geochemistry of recently discovered iron-rich micrometeorites from 2.7 billion–year–old limestones could serve as a proxy for ancient gas concentrations. When micrometeorites entered the atmosphere, they melted and preserved a record of atmospheric interaction. We model the motion, evaporation, and kinetic oxidation by CO2 of micrometeorites entering a CO2-rich atmosphere. We consider a CO2-rich rather than an O2-rich atmosphere, as considered previously, because this better represents likely atmospheric conditions in the anoxic Archean. Our model reproduces the observed oxidation state of micrometeorites at 2.7 Ga for an estimated atmospheric CO2 concentration of >70% by volume. Even if the early atmosphere was thinner than today, the elevated CO2 level indicated by our model result would help resolve how the Late Archean Earth remained warm when the young Sun was ~20% fainter.Lengger, S.K., Rush, D., Mayser, J.P., Blewett, J., Schwartz-Narbonne, R., Talbot, H.M., Middelburg, J.J., Jetten, M.S.M., Schouten, S., Sinninghe Damsté, J.S., Pancost, R.D., 2019. Dark carbon fixation in the Arabian Sea oxygen minimum zone contributes to sedimentary organic carbon (SOM). Global Biogeochemical Cycles 33, 1715-1732.: In response to rising CO2 concentrations and increasing global sea surface temperatures, oxygen minimum zones (OMZ), or “dead zones”, are expected to expand. OMZs are fueled by high primary productivity, resulting in enhanced biological oxygen demand at depth, subsequent oxygen depletion, and attenuation of remineralization. This results in the deposition of organic carbon‐rich sediments. Carbon drawdown is estimated by biogeochemical models; however, a major process is ignored: carbon fixation in the mid‐ and lower water column. Here, we show that chemoautotrophic carbon fixation is important in the Arabian Sea OMZ; and manifests in a 13C‐depleted signature of sedimentary organic carbon. We determined the δ13C values of Corg deposited in close spatial proximity but over a steep bottom‐water oxygen gradient, and the δ13C composition of biomarkers of chemoautotrophic bacteria capable of anaerobic ammonia oxidation (anammox). Isotope mixing models show that detritus from anammox bacteria or other chemoautotrophs likely forms a substantial part of the organic matter deposited within the Arabian Sea OMZ (~17%), implying that the contribution of chemoautotrophs to settling organic matter is exported to the sediment. This has implications for the evaluation of past, and future, OMZs: biogeochemical models that operate on the assumption that all sinking organic matter is photosynthetically derived, without new addition of carbon, could significantly underestimate the extent of remineralization. Oxygen demand in oxygen minimum zones could thus be higher than projections suggest, leading to a more intense expansion of OMZs than expected.Plain Language Summary: Oxygen minimum zones are areas in the ocean in which algae produce large amounts of organic material. When this sinks towards the seafloor, all oxygen at depth is used up. This results in vast “dead zones” where almost no oxygen is available to sustain life. With global warming, and increased nutrients from rivers, dead zones are forecast to expand. Computer models can calculate this, by considering algal production, and the amount of material delivered to the seafloor. However, these models often ignore a major process: anaerobic bacteria in the deeper water column, that can live at the edge or in the middle of these dead zones, which can also produce organic material from the dissolved CO2. In this study, we used the fact that these bacteria add a distinct signature to the organic material, to show that one fifth of the organic matter on the seafloor could stem from bacteria living in these dead zones. Thus, models that have missed out on considering this contribution could have underestimated the extent of oxygen depletion we are to expect in a future, warming world. A more intense expansion of dead zones than expected could have severe ecological, economical (fisheries), and climatic consequences.Levin, S.R., Gandon, S., West, S.A., 2020. The social coevolution hypothesis for the origin of enzymatic cooperation. Nature Ecology & Evolution 4, 132-137. the start of life, the origin of a primitive genome required individual replicators, or genes, to act like enzymes and cooperatively copy each other. The evolutionary stability of such enzymatic cooperation poses a problem, because it would have been susceptible to parasitic replicators that did not act like enzymes but could still benefit from the enzymatic behaviour of other replicators. Existing hypotheses to solve this problem require restrictive assumptions that may not be justified, such as the evolution of a cell membrane before the evolution of enzymatic cooperation. We show theoretically that, instead, selection itself can lead to replicators grouping themselves together in a way that favours cooperation. We show that the tendency to physically associate with others and cooperative enzymatic activity can coevolve, leading to the evolution of physically linked cooperative replicators. Our results shift the empirical problem from a search for special environmental conditions to questions about what types of phenotypes can be produced by simple replicators.Lewis, C.B., Walker, B.D., Druffel, E.R.M., 2020. Isotopic and optical heterogeneity of solid phase extracted marine dissolved organic carbon. Marine Chemistry 219, 103752. dissolved organic carbon (DOC) is the ocean's largest exchangeable reservoir of organic carbon. The biogeochemical cycling of DOC plays an important role in ocean carbon storage on various timescales. Solid-phase extraction (SPE) is a process used to isolate DOC from seawater for biogeochemical analysis. This study examines how DOC isotopic (Δ14C, δ13C) and optical (absorbance) properties of SPE-DOM change as a function of eluent volume (and hydrophobicity). These properties were measured in 28 SPE-DOC fractions incrementally eluted from Bond Elut PPL (styrene-divinylbenzene polymer) cartridges, totaling 32 mL of methanol. We show that the early eluted SPE-DOC has distinctly different ?14C and δ13C values than those eluted later. This study reveals isotopic heterogeneity as a function of SPE-DOC elution volume. These results show a partitioning of two distinct sources of SPE-DOC during elution, indicating a gradual transition from “marine-like” DOC to “terrestrial-like” DOC along a hydrophobicity continuum.Li, C., Busquets, R., Campos, L.C., 2020. Assessment of microplastics in freshwater systems: A review. Science of The Total Environment 707, 135578. reliance on plastic for a vast number of consumer products, many of them single-use, results in their continuous entry into aquatic environments. Plastic waste can fragment into smaller debris, some with a diameter?<?5?mm (microplastics). Microplastics are of growing concern especially since 2014, however to date research on microplastic pollution has mainly focused on marine environments, partly because it has been mistakenly thought that sewage treatment plants could remove all plastic debris. To understand the impact of microplastic pollution in freshwater environments, an assessment of research on the sources, distribution and effects of microplastics, and trends in their analysis and policy has been carried out. Main sources of microplastic found in freshwater environments include synthetic textiles, personal care products, industrial raw materials and the improper disposal of plastic waste. Microplastic pollution is a global issue that presents with a broad range of concentration: for example, 3.5?×?10^3 microplastic units·L?1 were reported in sediment of Lake Huron, in the US and as low as 1.2×10?4?units·L?1 in countries with sparse population such as Mongolia. The main polymer constituents of microplastics found in freshwaters have been identified as polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET), accounting for 70% of the total, each with a very similar frequency of occurrence. Despite microplastics being relatively inert, they are found to cause some effects in aquatic organisms. Future work should focus on monitoring microplastic pollution in regions from where there is currently scarce published data (e.g. South America, Africa and North Asia) and the study of their sources, stability, transport and effects to freshwater ecosystems. The establishment of standardized monitoring methods will allow for the comparison of data from different geographic areas. This information will inform measures to reduce the release and occurrence of microplastics in aquatic environments.Li, D., Shi, Q., Mi, N., Xu, Y., Wang, X., Tao, W., 2020. The type, origin and preservation of organic matter of the fine-grain sediments in Triassic Yanhe Profile, Ordos Basin, and their relation to paleoenvironment condition. Journal of Petroleum Science and Engineering 188, 106875. Chang 7 oil layer in Yanhe Profile develops comprehensive fine-grained sediments, showing great significance to hydrocarbon exploration. Based on nineteen samples, organic elements, maceral identification, vitrinite reflectance (Ro), biomarkers and inorganic elements were tested. The results show that the fine-grain sediments have relatively high clay minerals and are mainly silicate and clay source rocks, showing good-excellent source rock quality at the bottom with the decreasing quality towards the top. The rock pyrolysis, maceral identification and Ro imply that the organic matter (OM) type is Type II with plankton and bacterials as the main organic origin, entering maturity stage. Biomarkers, major and trace elements manifest that the fine-grain sediments deposited in weak oxidizing-weak reducing environment with fresh water. The diagrams of OEP-CPI and C29steraneββ(ββ+αα)-αααC29sterane 20S(20R + 20S) also reflect the maturity stage of organic matter. The Al/Si ratios are relatively big, implying the clay minerals content is high. This is in accordance with XRD analyses. Trace elements results demonstrate the high paleoproductivity, fresh water, and cold and dry weather. The increasing salinity, anoxic condition, and warm and humid climate are in favor of OM enrichment and preservation. This contribution provides systematic geologic foundation for hydrocarbon exploration and development of fine-grained sediments in Ordos Basin.Li, F., Thevenon, A., Rosas-Hernández, A., Wang, Z., Li, Y., Gabardo, C.M., Ozden, A., Dinh, C.T., Li, J., Wang, Y., Edwards, J.P., Xu, Y., McCallum, C., Tao, L., Liang, Z.-Q., Luo, M., Wang, X., Li, H., O’Brien, C.P., Tan, C.-S., Nam, D.-H., Quintero-Bermudez, R., Zhuang, T.-T., Li, Y.C., Han, Z., Britt, R.D., Sinton, D., Agapie, T., Peters, J.C., Sargent, E.H., 2020. Molecular tuning of CO2-to-ethylene conversion. Nature 577, 509-513. electrocatalytic reduction of carbon dioxide, powered by renewable electricity, to produce valuable fuels and feedstocks provides a sustainable and carbon-neutral approach to the storage of energy produced by intermittent renewable sources. However, the highly selective generation of economically desirable products such as ethylene from the carbon dioxide reduction reaction (CO2RR) remains a challenge. Tuning the stabilities of intermediates to favour a desired reaction pathway can improve selectivity, and this has recently been explored for the reaction on copper by controlling morphology, grain boundaries, facets, oxidation state and dopants. Unfortunately, the Faradaic efficiency for ethylene is still low in neutral media (60 per cent at a partial current density of 7 milliamperes per square centimetre in the best catalyst reported so far9), resulting in a low energy efficiency. Here we present a molecular tuning strategy—the functionalization of the surface of electrocatalysts with organic molecules—that stabilizes intermediates for more selective CO2RR to ethylene. Using electrochemical, operando/in situ spectroscopic and computational studies, we investigate the influence of a library of molecules, derived by electro-dimerization of arylpyridiniums11, adsorbed on copper. We find that the adhered molecules improve the stabilization of an ‘atop-bound’ CO intermediate (that is, an intermediate bound to a single copper atom), thereby favouring further reduction to ethylene. As a result of this strategy, we report the CO2RR to ethylene with a Faradaic efficiency of 72 per cent at a partial current density of 230 milliamperes per square centimetre in a liquid-electrolyte flow cell in a neutral medium. We report stable ethylene electrosynthesis for 190 hours in a system based on a membrane-electrode assembly that provides a full-cell energy efficiency of 20 per cent. We anticipate that this may be generalized to enable molecular strategies to complement heterogeneous catalysts by stabilizing intermediates through local molecular tuning.Li, H., Zhang, J., Xu, Q., Hou, C., Sun, Y., Zhuang, Y., Han, S., Wu, C., 2020. Influence of asphaltene on wax deposition: Deposition inhibition and sloughing. Fuel 266, 117047. are the heaviest and most polar constituents of crude oils. The influences of asphaltene on wax deposition were investigated with model oils utilizing a Taylor-Couette device. The composition and rheological properties of the deposits and the chemical properties of the asphaltenes entrained in the deposits were analyzed. Three main observations were obtained: (a) Wax deposition rate decreases in the presence of asphaltenes while the wax content of the deposit increases. The carbon number distribution of the deposit and the critical carbon number of the deposition process were also observed to vary due to the presence of asphaltenes. (b) The asphaltene content of the deposit constantly increases as time elapses and eventually reaches several times higher than that of the original oil. The asphaltenes entrained in the deposits are of higher polarity and molecular weight than the asphaltenes originally present in the oil. (c) When the asphaltene content of the oil is above 0.2?wt%, deposits slough off frequently as asphaltenes alter the microstructure of the deposit and lower its yield strength.Li, J., Roche, B., Bull, J.M., White, P.R., Davis, J.W., Deponte, M., Gordini, E., Cotterle, D., 2020. Passive acoustic monitoring of a natural CO2 seep site – Implications for carbon capture and storage. International Journal of Greenhouse Gas Control 93, 102899. the range at which an acoustic receiver can detect greenhouse gas (e.g., CO2) leakage from the sub-seabed is essential for determining whether passive acoustic techniques can be an effective environmental monitoring tool above marine carbon storage sites. Here we report results from a shallow water experiment completed offshore the island of Panarea, Sicily, at a natural CO2 vent site, where the ability of passive acoustics to detect and quantify gas flux was determined at different distances. Cross-correlation methods determined the time of arrival for different travel paths which were confirmed by acoustic modelling. We develop an approach to quantify vent bubble size and gas flux. Inversion of the acoustic data was completed using the modelled impulse response to provide equivalent propagation ranges rather than physical ranges. The results show that our approach is capable of detecting a CO2 bubble plume with a gas flux rate of 2.3?L/min at ranges of up to 8?m, and determining gas flux and bubble size accurately at ranges of up to 4?m in shallow water, where the bubble sound pressure is 10?dB above that of the ambient noise.Li, J., Zhang, T., Lin, D., Zhang, W., Liu, J., Li, H., Li, Y., 2019. Relation and contribution rate of graptolite to organic matter enrichment in shale: A case study from Well YS118 at the southern margin of the Sichuan Basin. Natural Gas Industry 39, 40-45. Chinese. High-carbon content and graptolite-rich black shale is developed in the Lower Silurian Longmaxi Formation in the southern China. Graptolite acts as important biological inputs to shale, but its effects on organic matter enrichment and its hydrocarbon generation mechanisms are currently less researched. Moreover, no common agreement has been reached in terms of the effects of graptolite on organic matter enrichment. To deal with this situation, this paper analyzed the elemental compositions of graptolite based on the analysis and test results of 124 shale samples taken from the base of the Longmaxi Formation in the typical well YS118 at the southern margin of the Sichuan Basin, including graptolite abundance, whole-rock total organic carbon(TOC), surrounding rock TOC, and energy spectrum of graptolite and surrounding rock. Then, the vertical variation characteristics of graptolite abundance in the high-quality shale interval at the base of the Longmaxi Formation were elucidated. Finally, the correlation between graptolite abundance and organic matter enrichment was explored in the P. persculptus and C. vesiculosus belts to quantitatively characterize the contribution of graptolite abundance to organic matter in different belts. And the following research results were obtained. First, carbon is the main element in the graptolite of the Longmaxi Formation shale, and its content is higher, ranging from 27.23% to 32.25%. Second, graptolite has a higher TOC content and greater carbon enrichment than the surrounding rocks. Third, the whole-rock TOC is obviously higher than the surrounding rock TOC, graptolite abundance is well correlated with the whole-rock TOC, and graptolite is an important contributor to the organic matters of shale. Fourth, the contribution rates of graptolite in the P. persculptus and A. ascensus belts to organic matters are 58.5% and 55.3%, respectively, suggesting that graptolite is the primary source for the organic matters of shale, while those in the P. acuminatus and C. vesiculosus belts are 24.23% and 13.65%, respectively, and the organic matter enrichment is under the joint control of graptolite and other organisms. In conclusion, graptolite abundance can well reflect the enrichment degree of organic matters in shale.Li, K., Rimmer, S.M., Presswood, S.M., Liu, Q., 2020. Raman spectroscopy of intruded coals from the Illinois Basin: Correlation with rank and estimated alteration temperature. International Journal of Coal Geology 219, 103369. spectroscopy was used to evaluate rank for a series of coals collected adjacent to an igneous intrusion. For these intruded coals, Raman parameters for collotelinite and its coked equivalent show complex changes during the transformation from low to very high levels of maturity (with vitrinite reflectance increasing from 0.55% to 5.0%). With increasing coal rank up to anthracite-level reflectance, the Raman spectra show a decrease in both G band full width at half maximum (FWHM) and D band intensity. The D band shape becomes increasingly asymmetric during the bituminization and de-bituminization stages, whereas in the anthracitization stage, the width of the D and G bands continues to decrease while D band intensity increases. In meta-anthracites (as seen in the ancillary Hunan samples), the G band has a low intensity and undergoes an apparent broadening due to the presence of the D2 band that occurs as a shoulder on the G band.Differences in Raman spectral parameters for vitrinite and inertinite macerals suggest differences in molecular structure between the macerals; as such, the heterogeneous nature of coal may affect Raman spectral results significantly if different maceral types are not considered. Within individual samples, Raman spectra indicate a high level of structural homogeneity between and within vitrinite particles, allowing assessment of differences between samples of different ranks.For vitrinite, the Raman spectral parameters G FWHM and DAs/GA (Area(1100-s)/Area(s-1650), s is the saddle point between 1100 cm?1 and 1650 cm?1) are highly correlated (R2 > 0.9) with vitrinite reflectance (Rr) and maximum alteration temperature (Tpeak), and allow establishment of geothermometers over the temperature range of ~70–300 °C that can be used to evaluate temperatures attained in intruded coals.Li, Q., Zhu, J., Li, S., Zhang, R., Xiao, T., Sand, W., 2020. Interactions between cells of Sulfobacillus thermosulfidooxidans and Leptospirillum ferriphilum during pyrite bioleaching. Frontiers in Microbiology 11, 44. doi: 10.3389/fmicb.2020. 00044. and Leptospirillum occur frequently in leaching systems. Here we investigated the effects of cells of L. ferriphilum on biofilm formation and leaching performance by S. thermosulfidooxidans. The effects were caused by the presence of L. ferriphilum or an addition of pyrite leach liquor from L. ferriphilum. Data show that the number of attached S. thermosulfidooxidans on pyrite increases, if the pyrite had been pre-colonized by living biofilms of L. ferriphilum, while it decreases if the pre-colonized biofilms had been inactivated. Coaggregation between S. thermosulfidooxidans and L. ferriphilum occurs during the dual-species biofilm formation, but different effects on bioleaching were noted, if the preculture of L. ferriphilum had been different. If L. ferriphilum had been pre-colonized on a pyrite, significantly negative effect was shown. However, if the two species were simultaneously inoculated into a sterile leaching system, the bioleaching efficiency was better than that of a pure culture of S. thermosulfidooxidans. The effect might be related to a metabolic preference of S. thermosulfidooxidans. If S. thermosulfidooxidans performed leaching in a filtered pyrite leachate from L. ferriphilum, the cells preferred to oxidize RISCs instead of ferrous ion and the number of attached cells decreased compared with the control. This study gives an indication that in a short-term multi-species leaching system the role of S. thermosufidooxidans may be related to the time of its introduction.Li, S., Wang, Q., Zhang, H., Zhang, Y., Wan, X., Martín-Closas, C., 2020. Filling a gap in the evolution of charophytes during the Turonian to Santonian: Implications for modern physiognomy. Review of Palaeobotany and Palynology 274, 104154. fossil record of Turonian to Santonian charophytes is very poor worldwide, probably due to the limited non-marine records from this age, when there was a global high stand in the relative sea level and, thus, a reduction in non-marine habitats. After this gap, the charophyte floras changed to their modern physiognomy, with dominance of the Characeae. Charophytes from the Turonian to Santonian in the Songliao Basin help to fill this significant gap in the evolution of charophytes. The recorded flora is formed by one member of the Clavatoraceae, Atopochara trivolvis var. restricta, and a greater diversity of Characeae, including Nodosochara (Turbochara) heilongjiangensis comb. nov., Lamprothamnium ellipticum, Lychnothamnus barbosai and Lychnothamnus quantouensis comb. nov. These findings showed that the Characeae began to dominate charophyte floras during the global sea level high stand, up to 8 Ma earlier than previously reported. The occurrence of the genus Lychnothamnus in the Turonian in the Songliao Basin represents the oldest record in Eurasia of this still-living genus. The occurrence of A. trivolvis var. restricta in the Turonian to Santonian in China in comparison with its previous records in the Albian?–Cenomanian in Europe indicates that this variety survived as a relict in North China, while the more-derived variety Atopochara trivolvis var. multivolvis had evolved elsewhere. The charophyte flora thrived in large, shallow, permanent freshwater lakes and sometimes in palustrine settings of the Quantou, Qingshankou and Yaojia formations, which explains its higher biodiversity in contrast with the other records that belong mainly to brackish settings.Li, S., Wang, Q., Zhang, K., Li, Z., 2020. Monitoring of CO2 and CO2 oil-based foam flooding processes in fractured low-permeability cores using nuclear magnetic resonance (NMR). Fuel 263, 116648. flooding is an important method in CO2 enhanced oil recovery (EOR) but is usually accompanied by a low efficiency for the fractured low-permeability formation due to CO2 low viscosity and high mobility. In this paper, a comprehensive experimental research effort including flooding and NMR testing is conducted to investigate the oil recovery and mobility control effects of a novel CO2 oil-based foam in fractured low-permeability cores. First, the foaming performance of the compound surfactant SF in crude oil that consists of Span20 and fluorochemical surfactant F-1 is evaluated by the blender stirring method. The surfactant SF exhibits a good foaming performance in crude oil with a foam volume of 290 mL and a half-life of 352 s. The bubble film is notably thickened, which results in a stable oil-based foam. Second, CO2 flooding and CO2 oil-based foam flooding in nonfractured and fractured cores are conducted under reservoir conditions. CO2 oil-based foam flooding can significantly improve the oil recovery and increase the sweep volume of injected CO2. Consequently, the oil recovery in fractured cores increases by 47.8%, and that in nonfractured cores increases by 39.1%. Third, the residual oil saturation in the cores is tested by NMR. The residual oil saturation of fractured and nonfractured cores after CO2 oil-based foam flooding is low and distributed evenly, indicating that CO2 oil-based foam reduces CO2 mobility and yields a relatively uniform displacement throughout the core.Li, Y., Lan, L., Wang, K., Yang, Y., 2019. Differences in lacustrine source rocks of Liushagang Formation in the Beibuwan Basin Acta Petrolei Sinica 40, 1451-1459. Beibuwan Basin is an important oil-rich basin in the offshore area of China. The oil and gas resources are mainly distributed in Weixi'nan sag, Wushi sag and Fushan sag. The proved oil reserves are about 4.05×108t, but the proved oil and gas reserves of each sag are significantly different. The enrichment degree of hydrocarbon in each sag of the Beibuwan Basin is closely related to the difference in lacustrine source rocks. From Weixi'nan sag to Wushi sag, Maichen sag and Fushan sag, the quality of source rocks in the Paleogene Liushagang Formation overall declines, the organic matter abundance of source rocks decreases, the dominant organic matter type changes from the sapropelic type to the mixed type, and the hydrocarbon generation potential of source rocks decreases. The analysis shows that although in the formation period of source rocks in Liushagang Formation, each sag in the Beibuwan Basin generally had high organic matter productivity in ancient lakes, there is still a certain difference in the organic matter sources of each sag, as well as the preservation conditions of organic matters. From Weixi'nan sag to Wushi sag, Maichen sag, Fushan sag and Haizhong sag, the organic matters from lacustrine algae are reduced, the organic matters from terrestrial higher plants are increased, and the preservation conditions of organic matters tend to be worse.Li, Y., Pang, T., Shi, J., Deng, X., Kong, G., Lu, X., 2020. Conversion method for linear retention indices in gas chromatography acquired using n-alkanes and n-fatty acid methyl esters. Chinese Journal of Chromatography 38, 244-249.Retention index (RI) is a powerful tool for gas chromatography-based structure elucidation of various compounds. In this study, linear RIs based on n-alkanes and n-fatty acid methyl esters in different temperature programs were fitted. Nearly identical first-order linearities were acquired with different temperature programs. The linear equations were y=1.0051x+318.51 (r2=1) and y=1.0362x+562.519 (r2=1) for polar (packed with polyethylene glycol) and semi-standard non-polar (packed with 5% diphenyl/95% dimethylpolysiloxane) columns, respectively. The variables x and y in the equations stand for RIs based on n-fatty acid methyl esters and n-alkanes, respectively. The established linearity was then verified using the reference RIs collected in the NIST mass spectral library, Golm metabolite library, and Fiehnmetabolite library. The RI values converted using both the acquired equations finely matched those in the references. The established relationship between the two kinds of RIs can be used to expand the RI references and decrease the number of RI acquisition experiments.Li, Y., Talalay, P.G., Sysoev, M.A., Zagorodnov, V.S., Li, X., Fan, X., 2020. Thermal heads for melt drilling to subglacial lakes: Design and testing. Astrobiology 20, 142-156. subglacial lakes are often considered suitable analogues to extraterrestrial subglacial aqueous environments. Recently, an environmentally friendly RECoverable Autonomous Sonde (RECAS) was designed at the Polar Research Center of Jilin University (JLU) to sample the water of subglacial lakes without contamination. In this regard, the development of a fast-penetration thermal head is the key issue for RECAS. Two different prototypes were designed and tested at the JLU ice-well to determine the optimal design and operation parameters of the thermal heads. Practical top and bottom thermal heads were then designed based on one of the prototypes, which can penetrate ice at an average rate of 1.88?m/h. The test results for the RECAS thermal heads show that the rate of penetration (ROP) can be 1.80–1.95?m/h in ?10°C ice, and the axial load on the thermal head only affects the ROP when it is lower than a specified threshold. The decrease of the ice temperature from ?10°C to ?30°C leads to a decrease of 17% in the ROP. The bottom thermal head can drill into dirty ice, and a simple collector positioned above the head can collect solid particles suspended in the melted ice. The top thermal head exhibited a long lifetime and stable heating performance after being powered in water for 2 weeks. In addition, the ice temperature near the borehole was monitored to evaluate the range of heat disturbance caused by the thermal head.Li, Y., Wang, Y., Wang, J., Pan, Z., 2020. Variation in permeability during CO2–CH4 displacement in coal seams: Part 1 – Experimental insights. Fuel 263, 116666. injection of CO2 into deep coal seams can improve the recovery of CH4 and contribute to the geological sequestration of CO2. To reveal the controlling factors associated with CO2 displacing CH4, experiments were conducted to simulate the process under different confining pressures (8, 12, 16, and 20 MPa) and CO2 injection pressures (1–6 MPa). The results show that coal can adsorb more CO2 than CH4. However, the permeability of CH4 is greater than that of CO2 under inlet gas pressures of 1–5 MPa. For CH4 saturated coals, the CH4 desorption volume is higher under CO2 displacing conditions compared to pure CH4 desorption processes under the same pressures. The coal adsorbed CO2 decreases under high pore and confining pressures, indicating the displacement results may be better in shallow buried coals. The axial, radial, and bulk strains of coal show steady, sharp, and then slow declining trends with decreasing pore pressures, and the inflection points generally occur at 5.25 and 3.25 MPa. Meanwhile, the strain in three directions decreases exponentially with the increase of effective stress, and the radial strain is higher than the axial strain under each confining pressure. With the combined influences of effective stress, matrix swelling/shrinkage, and gas slippage, the permeability decreases first and then increases with the decrease of pore pressure. With the decrease of pore pressure and the increase of confining pressure, the combined influence of the three factors on coal permeability gradually weakens. The results would be beneficial for controlling the injection process and permeability variation predicting during CO2 sequestration and the replacement of CH4 in coals at different burial depths.Li, Z., Huang, H., Zhang, S., 2020. The effect of biodegradation on bound biomarkers released from intermediate-temperature gold-tube pyrolysis of severely biodegraded Athabasca bitumen. Fuel 263, 116669. severely biodegraded Athabasca oil sand bitumens from a single bitumen column have been pyrolyzed in gold tube at 2 °C/h to 300–525 °C with a step of 25 °C and their pyrolysates are geochemically characterized by gas chromatography-mass spectrometry. Sample A situated at the top of bitumen column is less biodegraded than sample B, which is located at the bottom. While newly released biomarkers mixed with preexisted bio-resistant species in pyrolysates makes reaction mechanism elucidation difficult, adsorbed and occluded biomarkers are likely released at intermediate-temperature pyrolysis (<425 °C) but covalently bonded biomarkers are mainly released at high-temperature (≥425 °C). Biodegradation influence on bound biomarkers has been demonstrated for the first time by the absences of regular steranes and diasteranes in both samples and C33–C35 homohopanes in sample B of intermediate-temperature pyrolysates. Unusual variation of C30 17α(H), 21β(H) hopane (C30H) involved ratios in sample B also suggests that bound C30H moiety has been partially biodegraded. Caution should be taken when bound biomarkers are applied to reconstruct original source input or bitumen family classification as these bound compounds may not represent the original signatures in oil before biodegradation. However, no biodegradation influence has been recognized in high-temperature pyrolysates from 425 °C to 525 °C.Li, Z., Li, L., McKenna, K.R., Schmidt, M., Pollet, P., Gelbaum, L., Fernández, F.M., Krishnamurthy, R., Liotta, C.L., 2019. The oligomerization of glucose under plausible prebiotic conditions. Origins of Life and Evolution of Biospheres 49, 225-240. prebiotic origin of polysaccharides, the largest class of biopolymers by mass in extant biology, has seldom been investigated experimentally. Herein, we report on the acid-catalyzed condensation of aqueous solutions of glucose, a model monosaccharide, under plausible prebiotic conditions employing a wet-dry (night-day) protocol with 0.01?M HCl at 50?°C. This protocol leads to the formation of oligosaccharides containing up to eight monomeric units identified by high resolution mass spectrometry. The regio- and stereochemistry of the oligomeric acetal linkages, as well as the quantitative analysis of glucose conversion, are elucidated by combining 1H, 13C and 2D NMR spectroscopy. Ten out of eleven possible acetal linkages, including α- and β- anomers, have been identified with the α- and β- 1,6-acetals being the dominant linkages observed. In addition, the acid-catalyzed oligomerization of several glucose disaccharides such as cellobiose, maltose, and gentiobiose are presented along with an accompanying comparison with the corresponding oligomerization of glucose.Liang, H., Xu, F., Grice, K., Xu, G., Holman, A., Hopper, P., Fu, D., Yu, Q., Liang, J., Wang, D., 2020. Kinetics of oil generation from brackish-lacustrine source rocks in the southern Bohai Sea, East China. Organic Geochemistry 139, 103945. generation (C14+ hydrocarbons) of three Type II kerogen samples isolated from brackish-lacustrine mudstones from Palaeogene strata (Ed3, Es1, Es3) in the southern Bohai Sea was simulated by closed-system gold tube experiments. In addition, a series of complementary analyses (Rock-Eval pyrolysis, total organic carbon, vitrinite reflectance, trace element, X-ray diffraction and flash pyrolysis-gas chromatography–mass spectrometry) were also performed to identify the bulk geochemistry, palaeo-environment and chemical composition of the kerogen. The aim of this study was to achieve a better understanding of the kinetics of oil generation from lacustrine source rocks in the southern Bohai Sea. The results show that the three samples are Type II source rocks deposited in similar palaeo-environments (hot and arid climates, anoxic conditions, and brackish water in shallow to semi-deep lakes) with consequent similarity in the chemical compositions of their kerogens. The organic matter inputs are predominantly composed of lacustrine microalgae, with a relatively small contribution from land plants. The activation energies of oil generation from these samples show a range of 44–52?kcal/mol, with a frequency factor varying from 1.116?×?1014 to 1.274?×?1014 s?1. Due to the similar palaeo-environments and chemical composition, samples in this study exhibit strong consistencies in kinetic parameters. Transformation ratio (TR) evolution curves of oil generation from the three samples, calculated under a linear heating rate (3?K/Ma), exhibit a slight difference, which varies within 4?°C at a given TR. Due to the great similarities of the three kinetic models, an average kinetic model for the Type II brackish-lacustrine source rocks in the southern Bohai Sea was established. This model integrates the characteristics of the three kinetic models and is still dominated by activation energy of 52?kcal/mol. The geological temperature of the oil generation phase for the average model in the southern Bohai Sea is from 92 to 137?°C.Liang, J., Huang, X., Cai, W., Wang, Y., Chen, L., Zhang, Y., 2019. Source-to-sink system and exploration prospects of the Wilcox Formation in Perdido fold belt,Burgos Basin,Mexico Acta Petrolei Sinica 40, 1439-1450. at Wilcox Formation in the Perdido fold belt of the Burgos Basin, Mexico, where double-layered salt rock structures are widely developed, this study explores the history of plate activity and the distribution of major river systems based on logging, core, thin-section and 3D seismic data under limited well control conditions. The provenance direction was determined by the seismic sedimentary filling structure and debris composition; the characteristics of the deepwater sedimentary system were analyzed based on the single well facies, seismic reflections and attributes. The provenance of the Wilcox Formation and the deep-water fan deposition system under its control were comprehensively analyzed, the correlation between source-to-sink elements was explored, and the coupling model was established. The results show that the provenance of Wilcox Formation is mainly from the western Rocky Mountains and is transported to the study area by the two major river systems of Rio Grand and Colorado, characterized by bidirectional provenance. Channelized lobe, proximal lobe and distal lobe are mainly developed in this area. Among them, the channelized lobe is characterized by coarser particles and better reservoir property, and is the most favorable sedimentary facies belt. The overburdened hugely-thick salt rock of Wilcox Formation has low density and high thermal conductivity, and thus can reduce formation temperature, slow down compaction and cementation, which is conducive to the preservation of primary pores in subsalt reservoirs. Extremely favorable conditions for deposition of deep-water fan in the Perdido fold belt are created by abundant sediment supply and an efficient shelf-transportation system. The source-to-sink model is represented by the Rocky Mountains-Rio Grand, Colorado drainage system-shelf edge delta-canyons-deep-water fan mode. In addition to the low degree of exploration, superior source conditions, and extensive sand body distribution in the Perdido fold belt, many favorable conditions are provided by the double-layered salt rock structure for oil and gas accumulation, presenting a broad exploration space and huge potential.Liang, T., Zou, Y.-R., Zhan, Z.-W., Lin, X.-H., Shi, J., Peng, P.a., 2020. An evaluation of kerogen molecular structures during artificial maturation. Fuel 265, 116979. solid-state NMR and XPS techniques were used to investigate structural changes in kerogen during oil generation process across a range of maturity. Kerogen was isolated from an shale rock collected from Well W161 in the Dongying Depression, Bohai, China. An artificial pyrolysis experiment was carried out in a closed gold tube system using a heating rate of 2 ℃/h during which 11 temperature-point samples were collected between 350 ℃ and 450 ℃ (Easy%Ro = 0.80 to 1.98). The initial kerogen was analysed using Rock-Eval and the samples were analysed using X-ray photoelectron spectroscopy (XPS) and solid-state 13C nuclear magnetic resonance (13C NMR) to study their functional groups and chemical structures. Six averaged molecular structure models of the initial kerogen and its residues (can not be dissolved by organic reagent) were established to study the changes occurring during oil and gas generation. The results showed that with an increase in temperature, the proportion of aliphatic carbon declined while aromatic carbon increased. After reaching peak oil maturity, a condensation reaction occurred in the residue; some aromatic carbons cracked from the kerogen and combined with the residue structure. Average aromatic cluster increment was calculated to quantify the increase in the size of aromatic clusters within the structures. It was established to evaluate the changes occurring in the molecular structure of type Ⅰ kerogen during heating. Based on these results, ConU (maximum condensation degree) and ConL (lowest condensation degree) are proposed to estimate the degree of condensation of samples with different maturities.Liao, P.-H., Yang, H.-H., Wu, P.-C., Abu Bakar, N.H., Urban, P.L., 2020. On-line coupling of simultaneous distillation–extraction using the Likens–Nickerson apparatus with gas chromatography. Analytical Chemistry 92, 1228-1235. distillation–extraction (SDE) using the Likens–Nickerson apparatus is a convenient technique used to isolate volatile organic compounds (VOCs) from complex liquid matrices. The technique combines steam distillation with solvent extraction. While analytical extractions are normally followed by off-line separation/detection, it is advantageous to couple extractions on-line with separation and detection systems that are employed in the same analytical workflow. Here, we have coupled the Likens–Nickerson apparatus on-line with a gas chromatograph hyphenated with a mass spectrometer. For that purpose, we have devised an automated liquid transfer setup comprising a peristaltic pump, control unit, customized transfer vial with a drain port, and an autosampler arm to deliver liquid extract aliquots at defined time points. The on-line SDE-GC/MS system enables one to record real-time extraction profiles. These profiles reveal extraction kinetics of various VOCs present in the extracted samples. The data sets were fitted with the first order kinetic equation to obtain numeric values characterizing the extraction process (rate constants ranging from 0.21 to 0.01 min–1 for the ethyl esters from C6 to C19). A comparison of on-line and off-line results reveals that the on-line system is more dependable, while the off-line analysis leads to artifacts. To demonstrate the operation of the on-line SDE-GC/MS system, we performed analyses of selected real samples (beer). The real-time data sets revealed extraction kinetics for VOCs present in these samples. The devised extraction-analysis system allows the analysts to make an evidence-based decision on the extraction time for different groups of analytes in order to maximize extraction yield and minimize analyte losses.Lin, K., Huang, X., Zhao, Y.-P., 2019. Combining image recognition and simulation to reproduce the adsorption/desorption behaviors of shale gas. Energy & Fuels 34, 258-269. gas stored in deep shale is in a supercritical state. Therefore, it is necessary to study the adsorption and desorption properties of supercritical shale gas. To accurately determine the state of methane (CH4) in the pores of deep shale, the fractal characteristics of several shale samples drilled at a depth of 2650 m are analyzed using scanning electron microscopy (SEM) and image analysis. We find nanopores with different fractal features in the shale. The effects of adsorption energy and substrate strain on adsorption capacity are clarified. The virial coefficients of CH4 are obtained by molecular dynamics (MD) simulations and are consistent with the experiment. The adsorption and desorption of CH4 in different fractal nanopores are modeled using grand canonical Monte Carlo (GCMC) simulations at different temperatures and pressures (from capillary condensation to supercritical state). Additionally, the gas-in-place (GIP), excess adsorption, and absolute adsorption isotherms are obtained. We find the crossover of excess adsorption isotherms, which was observed in the experiment, and the absolute adsorption amount increases with the increase in pressure in the case of ultrahigh pressure (>40 MPa). Moreover, we obtain an ultrahigh-pressure dual-site Langmuir equation, and it can accurately describe observed adsorption isotherms from low pressure to ultrahigh pressure. Our study visually reproduces the adsorption/desorption behaviors of CH4 under in situ conditions in deep shale and reveals their microscopic mechanism.Lin, X., Huang, M., Chen, H., Wang, J., Wang, R., 2019. Influence of different polar solvent extraction on pore structure in shale. Acta Petrolei Sinica 40, 1485-1494.'s pore type and structure will directly affect the occurrence and production of gas. To discuss the effect of soluble organic matters in shale on the pore structure, different polar soluble organic matters in the shale are separated and extracted in the order of n-hexane, dichloromethane and tetrahydrofuran. Further, using the field emission scanning electron microscope (FE-SEM)and low-temperature nitrogen adsorption tests, this paper comparatively analyzes the pore structure characteristics of original sample and raffinate, and explores the effects of different polar solvent extraction on the pore structure of shale. The results show that with the increasing of organic solvent polarity, the soluble organic matters in shale are dissolved in the order of saturated hydrocarbons, aromatic hydrocarbons and non-hydrocarbon components. The original pores mainly include four types:intergranular pores, intragranular pores, organic pores and micro-cracks. After the soluble organic matters are dissolved, the pore morphology is more irregular, thus forming more dissolved pores; some intergranular pores are filled with the detached debris. Solvent polarity is enhanced, the area of hysteresis loop is reduced, and the BJH pore volume and average pore size are increased, accompanied by insignificant change in the BET specific surface area. The dissolution of soluble organic matter has the effect of "enhancing pores" and "expanding pores" on shale, with the increased pore content ≤ 2 nm and relatively decreased pore content>2 nm. In the mesopore range, the percentage content of pore volume and specific surface area is decreased in the pores of 2-10 nm, with insignificant change in the pore size range of 10-30 nm and significant increase in the pore size range of 30-50 nm. The modification process of pore morphology is as follows:the "ink bottle" hole with a relatively large aperture ratio of bottle body to bottle neck→the "ink bottle" hole with a relatively small aperture ratio of bottle body to bottle neck→wedge-type hole→parallel plate hole.Liseroudi, M.H., Ardakani, O.H., Sanei, H., Pedersen, P.K., Stern, R.A., Wood, J.M., 2020. Origin of sulfate-rich fluids in the Early Triassic Montney Formation, Western Canadian Sedimentary Basin. Marine and Petroleum Geology 114, 104236. study investigates diagenetic and geochemical processes that control regional distribution and formation of sulfate minerals (i.e., anhydrite and barite) in the Early Triassic Montney Formation in the Western Canadian Sedimentary Basin. The generation of H2S in hydrocarbon reservoirs is often associated with the dissolution of sulfate minerals, as a major source of sulfate required for sulfate-reducing reactions. The formation of pervasive late diagenetic anhydrite and barite in the high H2S zone of the Montney Formation is therefore contrary to the normal paragenetic sequence of sour gas reservoirs.Petrographic observations revealed early and late anhydrite and barite cement. The early fine-crystalline anhydrite cement is dominant in northeastern British Columbia (low H2S zone), while the late-stage coarse-crystalline cement and fracture/vug-filling anhydrite are dominant in Alberta (high H2S zone). The bulk isotopic values (δ34S: +2.9 to +24.7‰ V-CDT, δ18O: ?11.2 to +15.7‰ V-SMOW) suggest that sulfate-rich fluids originated mainly from modified Triassic connate water was the origin of early anhydrite. In contrast, the SIMS isotopic values of late anhydrite (δ34S: +18.5 to +37‰ V-CDT, δ18O: +12 to +22‰ V-SMOW) and barite cement (δ34S: +23.3 to +39‰ V-CDT, δ18O: +13.2 to +18.7‰ V-SMOW) as well as fracture/vug-filling anhydrite (δ34S: +23.5 to +24.7‰ V-CDT, δ18O: +13.3 to +14.7‰ V-SMOW) from Alberta represents a mixed isotopic signature of Triassic connate water and contribution of dissolved sulfate-rich fluids derived from dissolution of Devonian evaporites.The 87Sr/86Sr isotope ratios of the fracture/vug-filling anhydrite (0.7092–0.7102) are highly radiogenic suggesting extensive water/rock interactions between sulfate-rich fluids and siliciclastic and basement rocks. The similar isotopic composition of the late anhydrite/barite and fracture/vug-filling anhydrite in western Alberta with Devonian evaporites isotopic signature, and the highly radiogenic 87Sr/86Sr ratio further supports sulfate-bearing fluids were mainly originated from underlying Devonian evaporites and migrated upwards through deep-seated faults/fractures to the Montney Formation.Liu, F., Li, R., Liu, X., Yang, M., Zhao, B., Wu, X., Qin, X., 2019. Study of gas accumulation under “source control” in western Sulige Gas Field, Ordos Basin Acta Sedimentologica Sinica 37, 1129-1139. sandstone gas reservoirs are distributed over a wide area in the western Sulige gas field,with interconnected and superposed gas-bearing sands. The main gas-bearing sands occur in the eighth member of the Shihezi Formation and the first member of the Shanxi Formation. These are sand bodies of a river delta sedimentary system. In this study,the geochemical characteristics of the gas from the study area were analyzed together with the characteristics of the source rocks and hydrocarbon generation in the basin to determine the gas accumulation characteristics and the extent to which the gas-water relationship is controlled by the source rocks. It is shown that the gas in the study area mainly migrated from SW to NE,from west to east,and from bottom to top. It was found that the study area,which is located within the triangular zone of three high-intensity hydrocarbon generation centers,produces abundant gas, not only from the three hydrocarbon generation areas but also in the study area itself,which is continually producing gas to this day. The effect of the source rocks is that,as the gas migrates and accumulates,it drives formation water northward and upward regionally. The general pattern in the study area is summed up as "southern gas and northern water, more water above and less below".Liu, H., Sun, W.-d., Deng, J., 2020. Statistical analysis on secular records of igneous geochemistry: Implication for the early Archean plate tectonics. Geological Journal 55, 994-1002. recent years, application of statistical analysis to a sufficiently large geochemical database has become more and more popular to reveal the onset and evolution of plate tectonics as a consequence of the development of computer science and storage technology. Here, we introduce a robust statistical method to process a filtered geochemical dataset including predominantly continental basaltic rocks through Earth's history. The results show that the average Sr concentrations gradually increased from 3.8 to 0 Ga, indicating a progressively growing depth of magma source as a result of secular cooling of the mantle. However, the average La/Yb and Sm/Yb ratios only started to increase at ca. 3.0 Ga. Considering the La–Yb and Sm–Yb fractionations are commonly attributed to the residual garnet crystallization, we interpreted that the geotherm of the magma source of continental basaltic rocks before 3.0 Ga might be higher than the stability limit of garnet. As such, there were little or no garnets in the residue during partial melting of the upwelling asthenospheric mantle or mantle plumes before 3.0 Ga, which also implied a higher continental geotherm during that time. Such a high geotherm could not support the formation of contemporaneous high‐pressure or medium‐pressure TTGs (tonalite–trondhjemite–granodiorite) by vertical tectonic models associated with upwelling mantle heating or delaminated lower crust melting in the early Archean. We therefore conclude that the plate tectonics had occurred by ca. 3.8 Ga in a hot subduction style and contributed to the formations of high‐ and medium‐pressure TTGs subsequently.Liu, J., An, Z., 2020. Leaf wax n-alkane carbon isotope values vary among major terrestrial plant groups: Different responses to precipitation amount and temperature, and implications for paleoenvironmental reconstruction. Earth-Science Reviews 202, 103081. focused on field measurements have been conducted to investigate how leaf wax n-alkane δ13C values vary among photosynthetic pathways (C3 vs. C4) or plant types (dicots, monocots, gymnosperms, magnoliids), and how n-alkane δ13C values respond to climate factors (precipitation, temperature). However, a systematic global analysis of plant n-alkane δ13C values with respect to major plant groups is still lacking, and the corresponding mechanism remains unknown. In this study, we compiled globally published n-alkanes δ13C data in modern plants. We find significantly negative correlations between δ13Cwt values and mean annual precipitation (MAP) for C3 plants (R2 = 0.30; p < .05), dicots (R2 = 0.28; p < .05) and magnoliids (R2 = 0.55; p < .05), but non-significant correlation between δ13Cwt values and MAP for C4 plants (R2 = 0.08; p = .12) or monocots (R2 = 0.01; p = .89). However, there are significantly positive correlations between δ13Cwt values and mean annual temperature (MAT) in C4 plants (R2 = 0.33; p < .05) and monocots (R2 = 0.35; p < .05), instead of weak correlations in C3 plants (R2 = 0.09; p < .05), dicots (R2 = 0.03; p < .05) and gymnosperms (R2 = 0.06; p = .06). These results indicate that n-alkane δ13C values in C3 dicots have more potential for paleoprecipitation reconstruction, while those in C4 monocots are more likely to indicate paleotemperature changes. Our study supports use of leaf wax n-alkane δ13C values to gain information about paleoprecipitation and paleotemperature, but only in an appropriate paleoecological context.Liu, P., Wang, X., Lin, Y., Liu, C., Li, X., Liu, W., 2020. Chemical and carbon isotope fractionations of alkane gases desorbed from confined systems and the application toward shale gas reservoir. Marine and Petroleum Geology 113, 104103. and desorption processes of shale gas possess particular characteristics compared to conventional natural gas. Previous studies conducted desorption experiments on fresh core samples to investigate the isotope and chemical fractionations during the desorption process. However, complete chemical and isotope fractionations cannot be obtained due to the loss of gases during the coring process. In this study, we utilized a modified experimental apparatus based on the fixed adsorption bed to conduct systematic desorption experiments in confined systems with different proportions of free and adsorbed gases. The results show that different adsorption capacities and non-synchronous desorption for alkane gas components are leading factors influencing chemical fractionation during the desorption process. Meanwhile, C1/C2 and C1/(C1+C2) vary with different proportions of adsorbed gases in the same adsorption matrix. Generally, isotope fractionation between the adsorbed and free phases during desorption follows the Rayleigh fractionation model. The linear correlations between proportions of adsorbed CH4 and isotope fractionation factors can be applied to predict the proportions of adsorbed gases. Calculations show that on average 55% of hydrocarbon gases exist at adsorbed state in shale gas from Yanchang Formation of Ordos Basin.Liu, S., Zhang, R., 2020. Anisotropic pore structure of shale and gas injection-induced nanopore alteration: A small-angle neutron scattering study. International Journal of Coal Geology 219, 103384. transport in the shale matrix is controlled by pore structure, which can ultimately influence natural gas production potential and carbon sequestration in shale gas reservoirs. In this study, in situ small-angle neutron scattering (SANS) measurements under methane and CO2 injections were employed to investigate two Marcellus Shale thin section samples cut parallel and perpendicular to the bedding. Marcellus Shale nanopores show intrinsic anisotropy over the detected length scale of 5–2000 ?. Microscopic gas transport could be inhibited due to the decrease of accessible porosity with increasing gas pressure. The degree of inhibition may be higher for CO2 than for methane, and for the direction normal to the bedding than in the bedding direction. In addition, under the condition of liquid CO2, higher porosity reduction for the direction normal to the bedding may insight into nanoscale anisotropic wettability in the shale matrix.Liu, W.-W., Pan, J., Feng, X., Li, M., Xu, Y., Wang, F., Zhou, N.-Y., 2020. Evidences of aromatic degradation dominantly via the phenylacetic acid pathway in marine benthic Thermoprofundales. Environmental Microbiology 22, 329-342. (Marine Benthic Group D archaea, MBG‐D) is a newly proposed archaeal order and widely distributed in global marine sediment, and the members in the order may play a vital role in carbon cycling. However, the lack of pure cultures of these oeganisms has hampered the recognition of their catabolic roles. Here, by constructing high‐quality metagenome‐assembled genomes (MAGs) of two new subgroups of Thermoprofundales from hydrothermal sediment and predicting their catabolic pathways, we here provide genomic evidences that Thermoprofundales are capable of degrading aromatics via the phenylacetic acid (PAA) pathway. Then, the gene sequences of phenylacetyl‐CoA ligase (PCL), a key enzyme for the PAA pathway, were searched in reference genomes. The widespread distribution of PCL genes among 14.9% of archaea and 75.9% of Thermoprofundales further supports the importance of the PAA pathway in archaea, particularly in Thermoprofundales where no ring‐cleavage dioxygenases were found. Two PCLs from Thermoprofundales MAGs, PCLM8‐3 and PCLM10‐15, were able to convert PAA to phenylacetyl‐CoA (PA‐CoA) in vitro, demonstrating the involvement of Thermoprofundales in aromatics degradation through PAA via CoA activation. Their acid tolerance (pH 5–7), high‐optimum temperatures (60°C and 80°C), thermostability (stable at 60°C and 50°C for 48?h) and broad substrate spectra imply that Thermoprofundales are capable of transforming aromatics under extreme conditions. Together with the evidence of in situ transcriptional activities for most genes related to the aromatics pathway in Thermoprofundales, these genomic, and biochemical evidences highlight the essential role of this ubiquitous and abundant archaeal order in the carbon cycle of marine sediments.Liu, X.-Q., Li, M., Zhang, C., Fang, R., Zhong, N., Xue, Y., Zhou, Y., Jiang, W., Chen, X.-Y., 2020. Mechanistic insight into the optimal recovery efficiency of CBM in sub-bituminous coal through molecular simulation. Fuel 266, 117137. this study, a newly created Fortran program was used to assist in the constructing of a sub-bituminous coal model (SCM). Followed by grand canonical Monte Carlo simulations, the adsorption behaviors of CBM adsorption on dry-/moisture-SCM systems have been systematically studied at different pressure-temperature conditions. A geological model with typical geothermal and pressure gradients was established to investigate the effect of coupled pressure and temperature on the absorption and recovery. As a result, pure-N2 injection has been confirmed to paly a negative role on CH4 recovery, whereas CO2 could effectively improve the CO2 sequestration and CH4 displacement. Meanwhile, the adsorption percentage (δ) and the recovery efficiency (η) were first put forward in terms of theoretical calculations. The results showed that, the δ was determined by pore size distribution of the SCM, adsorption temperature/pressure, moisture-containing in coal and the types of adsorbates. The value of ηCH4 is 53.07% in dry coal seam, whereas 47.20% is evaluated in moisture coal seam, the corresponding optimum mining depths are 600?m and 800?m, respectively. Remarkably, water-containing in coal seam has an obviously inhibitory effect on simultaneous extraction of coal and gas, and it should be valued in the follow-up studies. Based on this principle, the optimum mining depth for CO2-ECBM was predicted to be ～800?m in actual deep coal seams through our geological model. Our results provide a molecular-scale insight into CBM recovery efficiency in coal at different burial depths, and offer useful guidance for realistic exploitation.Liu, X., Jing, X., Ye, Y., Zhan, J., Ye, J., Zhou, S., 2020. Bacterial vesicles mediate extracellular electron transfer. Environmental Science & Technology Letters 7, 27-34. Gram-negative bacteria are known to release outer membrane vesicles (OMVs) into the surrounding environment during normal growth; OMVs perform diverse biological and environmental functions (e.g., virulence factor transport, horizontal gene transfer, quorum signaling, cellular defense, and cell-to-cell communication). However, the production of OMVs has not been reported in Geobacter species, and their role in extracellular electron transfer (EET) is unknown. Here, we demonstrate, for the first time, that Geobacter sulfurreducens releases OMVs containing abundant cytochromes that can promote EET from microbial cells to an anode. OMVs released by Geobacter cells not only promote exoelectrogen EET (1.73-fold higher current density in Shewanella oneidensis MR-1) but also confer electrogenic ability to non-exoelectrogens (G. sulfurreducens mutant strain ΔomcZ and Escherichia coli). These functions are mainly attributed to the abundance of c-type cytochromes bound on or entrapped in OMVs. Our findings suggest that redox-active OMVs can serve as shared mediators facilitating EET in natural ecosystems, representing an ecologically important but overlooked biological electron transfer process.Liu, X., Lai, J., Fan, X., Shu, H., Wang, G., Ma, X., Liu, M., Guan, M., Luo, Y., 2020. Insights in the pore structure, fluid mobility and oiliness in oil shales of Paleogene Funing Formation in Subei Basin, China. Marine and Petroleum Geology 114, 104228. structure is an important factor influencing reservoir properties of oil shales. Routine core analysis, thin section, scanning electron microscope (SEM), mercury injection capillary pressure (MICP) tests, Nuclear Magnetic Resonance (NMR), and computed tomography (CT) were used to provide insights into the pore throat distribution in oil shales of member 2 of Paleogene Funing Formation (E1f2) in Subei Basin, China, with the special aim to unravel the effect of pore structure on fluid mobility and oiliness. The relationships between NMR parameters, petrophysical property and capillary parameters are investigated. The results show that rock composition in the oil shales consist of quartz, feldspar, carbonate particles, clay minerals and organic matters. Pore systems consist of large-scale interparticle pores, intragranular dissolution pores, and small-scale micropores within clay minerals and the organic matter pores.Four types of pore structure (Type Ⅰ, Type Ⅱ, Type Ⅲ and Type Ⅳ) are divided according to the patterns of capillary curves, capillary parameters, NMR T2 (transverse relaxation time) spectrum and BVI (bulk volume of immovable fluid) values. From Type Ⅰ to Type Ⅳ pore structure, the maximum mercury saturation (SHgmax) and mercury extrusion efficiency are decreasing, and the SHgmax are less than 50% averagely, indicating the oil shales are characterized by very poor pore connectivity. The T2 spectrum changes from bi-modal behavior to uni-modal and the right peaks become lower or even disappearing from Type Ⅰ to Type Ⅳ pore structure. Fluid mobility is not primarily controlled by pore size, but dependent on the content of short T2 components (<1 ms). The micro-fractures as well as particles (mainly dolomites) filling them emit strong blue fluorescence. The edges of particles emit strong blue fluorescences and indicate that the interparticle pores are oil bearing. The carbonate particles are oil-wet, and intragranular dissolution pores within carbonate particles are fluorescent. Authigenic clay minerals are abundant in intercrystalline pores, and organic matters are abundant in organic pores, and they emit scattered strong blue fluorescence.Pore structure controlled fluid mobility and determined the microscopic oiliness and macroscopic oil bearing property or hydrocarbon productivity. The comprehensive study above gains insights into the microscopic pore structure and their controls on fluid mobility and oiliness in shale oil reservoirs, and this may have implications for resource potential evaluation and effective exploitation of oil shales.Liu, X., Tang, D., Ge, C., 2020. Distribution and sources of organic carbon, nitrogen and their isotopic composition in surface sediments from the southern Yellow Sea, China. Marine Pollution Bulletin 150, 110716. southern Yellow Sea (SYS) is a significant repository of sedimentary organic matter (SOM) and has been impacted by green tides since 2007; however, data on the distribution and quantitative contributions of different SOM sources has been scarce. TOC, TN and their δ13C and δ15N values were determined in 38 surface sediments. TOC and TN were high in central mud area and low in sand area. TOC was positively correlated with the abundance of fine-grained sediments, indicating that controlling factors of SOM were the sediment types and circulation system. The SOM included marine and terrestrial organic matter and anthropogenic nutrient inputs according to TOC/TN (5.8–14.3), δ13C (?25.1‰ to ?21.0‰) and δ15N (2.6‰–6.4‰). High terrestrial contributions in northern and western parts of SYS, were influenced by terrestrial materials and eroded substances of the abandoned Yellow River delta, respectively. In the central mud area of SYS, marine organic matter was dominant.Liu, Y., Shan, L., Guo, B., Sun, M., Wang, G., Wang, Q., 2020. Numerical solutions of heat transfer problems in gas production from seabed gas hydrates. Journal of Petroleum Science and Engineering 188, 106824. natural gas in gas hydrates is considered as a major resource of future clean energy. Producing natural gas from gas hydrates at seafloor presents a great challenge to the engineers due to low efficiency in heat transfer processes. A numerical model was developed in this study to investigate the temperature profiles along the hose assembly in the MRM for harvesting the natural gas from hydrates at the seafloor. Sensitivity analyses were carried out to find major factors affecting the delivering water temperature to the gas hydrate deposits. The result shows that decreasing the temperature of the injected water at surface will cause drop in the delivery temperature of water in the pipe. The drop in the surface temperature is transferred almost by the same amount to the drop in the delivering temperature with the pipe insulation used. The temperature of the water delivered to the gas hydrates drops slowly and linearly with water depth at high water injection rate, and sharply and non-linearly with water depth at low water injection rate. The delivery water temperature is strongly controlled by the pipe insulation but insensitive to it when the thermal conductivity of the insulation material is less than 0.0245?W/m-oC. The temperature in the riser annulus is not essentially affected by any of the invested parameters. A comparison between the numerical model and analytical model under the condition of homogeneous mixture flow was performed. The result shows a good agreement between them, which verified the numerical model.Liu, Y., Wang, W., Shah, S.B., Zanaroli, G., Xu, P., Tang, H., 2020. Phenol biodegradation by Acinetobacter radioresistens APH1 and its application in soil bioremediation. Applied Microbiology and Biotechnology 104, 427-437. accounts for a large proportion of the contamination in industrial wastewater discharged from chemical plants due to its wide use as a raw chemical. Residual phenol waste in water and soil significantly endangers human health and the natural environment. In this study, an Acinetobacter radioresistens strain, APH1, was isolated and identified for its efficient capability of utilizing phenol as sole carbon source for growth. A draft genome sequence containing 3,290,330 bases with 45 contigs was obtained, and 22 genes were found to be involved in phenol metabolism and 51 putative drug-resistance genes were annotated by genomic analysis. The optimal conditions for cell culture and phenol removal were determined to be 30?°C, pH 6.0, and a phenol concentration of 500?mg/L; the upper limit of phenol tolerance was 950?mg/L. Based on GC-MS analysis, the key metabolites including cis,cis-muconic acid, catechol, and succinic acid were detected. During bioremediation experiment using 450?mg/kg (dry weight) of phenol-contaminated soil, the strain APH1 removed 99% of the phenol within 3?days. According to microbial diversity analysis, the microbial abundance of Chungangia, Bacillus, Nitrospira, Lysinibacillus, and Planomicrobium increased after the addition of phenol. Furthermore, at day 23, the abundance of strain APH1 was greatly reduced, and the microbial diversity and structure of the whole microbial community were gradually recovered, indicating that strain APH1 would not affect this microbial ecosystem. These findings provide insights into the bioremediation of soil contaminated with phenol.Liu, Y., Ye, Q., Huang, W.-L., Feng, L., Wang, Y.-H., Xie, Z., Yong, S.-S., Zhang, S., Jiang, B., Zheng, Y., Wang, J.-J., 2020. Spectroscopic and molecular-level characteristics of dissolved organic matter in the Pearl River Estuary, South China. Science of The Total Environment 710, 136307. populations are expanding globally, resulting in great anthropogenic impacts on the organic matter in estuaries and regional carbon cycles. However, the molecular-level characteristics of dissolved organic matter (DOM) within highly disturbed estuaries are still not well understood. Here, water samples collected during two seasons (wet and dry) from the subtropical Pearl River Estuary of China were analyzed using absorption and fluorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to determine the spatiotemporal variations in the DOM characteristics. In the seaward direction, the abundances of chromophoric and fluorescent DOM decreased by greater percentages than the bulk dissolved organic carbon concentration. The spectroscopy and FT-ICR MS analyses collectively indicated seaward declines in the aromaticity of DOM and terrestrial DOM contributions from natural terrestrial markers and anthropogenic synthetic surfactants. In particular, the S content in DOM was much higher here than in previously reported estuaries, suggesting a strong anthropogenic impact on the estuarine DOM. Greater terrestrial and anthropogenic signatures in DOM were observed in the wet season than in the dry season. Importantly, this study implies that the terrestrial and anthropogenic contributions to DOM were strongly driven by season in the anthropogenically disturbed subtropical estuary.Liu, Z., Horton, D.E., Tabor, C., Sageman, B.B., Percival, L.M.E., Gill, B.C., Selby, D., 2019. Assessing the contributions of comet impact and volcanism toward the climate perturbations of the Paleocene-Eocene Thermal Maximum. Geophysical Research Letters 46, 14798-14806.: The Paleocene‐Eocene Thermal Maximum is marked by a prominent negative carbon‐isotope excursion, reflecting the injection of thousands of gigatons of isotopically light carbon into the atmosphere. The sources of the isotopically light carbon remain poorly constrained. Utilizing a multiproxy geochemical analysis (osmium isotopes, mercury, sulfur, and platinum group elements) of two Paleocene‐Eocene boundary records, we present evidence that a comet impact and major volcanic activity likely contributed to the environmental perturbations during the Paleocene‐Eocene interval. Additionally, Earth system model simulations indicate that stratospheric sulfate aerosols, commensurate with the impact magnitude, were likely to have caused transient cooling and reduced precipitation.Plain Language Summary: The Paleocene‐Eocene Thermal Maximum (~55.9 Ma) records a period of climate warming associated with the injection of thousands of gigatons of carbon into the atmosphere. However, the sources of the carbon are still unclear. Our study uses geochemical data (osmium isotopes, mercury, sulfur, and platinum group elements) of two North Atlantic Ocean drill cores across the Paleocene‐Eocene interval to suggest that both a comet impact and large‐scale volcanism occurred at that time. The comet is estimated to be small (~3.3 km diameter) with ~0.4 Gt carbon and thus cannot be responsible for the Paleocene‐Eocene Thermal Maximum. However, climate modeling suggests that the comet impact might have caused transient cooling and reduced precipitation.Liu, Z., Liu, D., Cai, Y., Yao, Y., Pan, Z., Zhou, Y., 2020. Application of nuclear magnetic resonance (NMR) in coalbed methane and shale reservoirs: A review. International Journal of Coal Geology 218, 103261. magnetic resonance (NMR) has been applied widely and successfully in conventional and unconventional reservoirs, and can be used to investigate petrophysical properties and fluid flow characteristics. This non-destructive, sensitive, and quick technique has been utilized in determination of pore type, porosity, pore size distribution, permeability prediction, wettability estimation, and fluid type, state and flow behavior.In this paper, the application of NMR to investigate coalbed methane and shale reservoirs is reviewed. Most of the reviewed studies are related to porosity and pore characteristics, which can be determined by analyzing the characteristics of the T2 distribution, allowing for examination of pore type and pore connectivity as well as calculation of total porosity and pore size distribution. Permeability models developed for reservoir rocks and based on porosity determined using NMR are well established and have been extended or modified to evaluate the permeability of coal or shale. Reviewed studies also include wettability investigation by comparing the subtraction of T2 distribution before and after fluid injection. Reviewed recent advances have further discussed the method of distinguishing fluid type, fluid state, and simulating fluid behavior using one-dimensional and two-dimensional NMR methods combined with changes of T2 distribution. The aim of this review is to provide readers with an overview of the capabilities of NMR and its extension to scientific research by improving the parameter optimization of the instrument and establishing the calculation method for effective surface relaxivity for coals or shales.Long, T., Clement, S.W.J., Xie, H., Liu, D., 2020. Design, construction and performance of a TOF-SIMS for analysis of trace elements in geological materials. International Journal of Mass Spectrometry 450, 116289. new TOF-SIMS with high spatial and mass resolution has been constructed and applied to the in-situ micro-scale analysis of trace elements in geological materials with complex structural and chemical features. Double second-order reflectrons without mesh between different electric field regions of achieve greatly improved secondary ion transmission and mass resolution. The new TOF-SIMS can produce an O2- beam of ca. 5 μm diameter with a beam intensity of ca. 5 nA and a secondary ion mass resolution of more than 20,000 (FWHM). Functionality has been demonstrated by the analysis of Ti and rare earth elements in zircon.Lopez Bedogni, G., Massello, L.F., Giaveno, A., Donati, R.E., Urbieta, S.M., 2019. A deeper look into the biodiversity of the extremely acidic Copahue volcano-Río Agrio System in Neuquén, Argentina. Microorganisms 8, 58. Copahue volcano-Río Agrio system, on Patagonia Argentina, comprises the naturally acidic river Río Agrio, that runs from a few meters down the Copahue volcano crater to more than 40 km maintaining low pH waters, and the acidic lagoon that sporadically forms on the crater of the volcano, which is studied for the first time in this work. We used next-generation sequencing of the 16S rRNA gene of the entire prokaryotic community to study the biodiversity of this poorly explored extreme environment. The correlation of the operational taxonomic units (OTUs)s presence with physicochemical variables showed that the system contains three distinct environments: the crater lagoon, the Upper Río Agrio, and the Salto del Agrio waterfall, a point located approximately 12 km down the origin of the river, after it emerges from the Caviahue lake. The prokaryotic community of the Copahue Volcano-Río Agrio system is mainly formed by acidic bacteria and archaea, such as Acidithiobacillus, Ferroplasma, and Leptospirillum, which have been isolated from similar environments around the world. These results support the idea of a ubiquitous acidic biodiversity; however, this highly interesting extreme environment also has apparently autochthonous species such as Sulfuriferula, Acidianus copahuensis, and strains of Acidibacillus and Alicyclobacillus.Love, G.D., Zumberge, J.A., Cárdenas, P., Sperling, E.A., Rohrssen, M., Grosjean, E., Grotzinger, J.P., Summons, R.E., 2020. Sources of C30 steroid biomarkers in Neoproterozoic–Cambrian rocks and oils. Nature Ecology & Evolution 4, 34-36. Article: Nettersheim, B.J., Brocks, J.J., Schwelm, A., Hope, J.M., Not, F., Lomas, M., Schmidt, C., Schiebel, R., Nowack, E.C.M., De Deckker, P., Pawlowski, J., Bowser, S.S., Bobrovskiy, I., Zonneveld, K., Kucera, M., Stuhr, M., Hallmann, C., 2019. Putative sponge biomarkers in unicellular Rhizaria question an early rise of animals. Nature Ecology & Evolution 3, 577-581.Reply to Comment: Hallmann, C., Nettersheim, B.J., Brocks, J.J., Schwelm, A., Hope, J.M., Not, F., Lomas, M., Schmidt, C., Schiebel, R., Nowack, E.C.M., De Deckker, P., Pawlowski, J., Bowser, S.S., Bobrovskiy, I., Zonneveld, K., Kucera, M., Stuhr, M., 2020. Reply to: Sources of C30 steroid biomarkers in Neoproterozoic–Cambrian rocks and oils. Nature Ecology & Evolution 4, 37-39.Lowe, D.R., Bishop, J.L., Loizeau, D., Wray, J.J., Beyer, R.A., 2019. Deposition of >3.7 Ga clay-rich strata of the Mawrth Vallis Group, Mars, in lacustrine, alluvial, and aeolian environments. GSA Bulletin 132, 17-30. presence of abundant phyllosilicate minerals in Noachian (&gt;3.7 Ga) rocks on Mars has been taken as evidence that liquid water was stable at or near the surface early in martian history. This study investigates some of these clay-rich strata exposed in crater rim and inverted terrain settings in the Mawrth Vallis region of Mars. In Muara crater the 200-m-thick, clay-rich Mawrth Vallis Group (MVG) is subdivided into five informal units numbered 1 (base) to 5 (top). Unit 1 consists of interbedded sedimentary and volcanic or volcaniclastic units showing weak Fe/Mg-smectite alteration deposited in a range of subaerial depositional settings. Above a major unconformity eroded on Unit 1, the dark-toned sediments of Unit 2 and lower Unit 3 are inferred to represent mainly wind-blown sand. These are widely interlayered with and draped by thin layers of light-toned sediment representing fine suspended-load aeolian silt and clay. These sediments show extensive Fe/Mg-smectite alteration, probably reflecting subaerial weathering. Upper Unit 3 and units 4 and 5 are composed of well-layered, fine-grained sediment dominated by Al-phyllosilicates, kaolinite, and hydrated silica. Deposition occurred in a large lake or arm of a martian sea. In the inverted terrain 100 km to the NE, Unit 4 shows very young slope failures suggesting that the clay-rich sediments today retain a significant component of water ice. The MVG provides evidence for the presence of large, persistent standing bodies of water on early Mars as well as a complex association of flanking shoreline, alluvial, and aeolian systems. Some of the clays, especially the Fe/Mg smectites in upper units 1 and 2 appear to have formed through subaerial weathering whereas the aluminosilicates, kaolinite, and hydrated silica of units 3, 4, and 5 formed mainly through alteration of fine sediment in subaqueous environments.Lowry, D., Fisher, R.E., France, J.L., Coleman, M., Lanoisellé, M., Zazzeri, G., Nisbet, E.G., Shaw, J.T., Allen, G., Pitt, J., Ward, R.S., 2020. Environmental baseline monitoring for shale gas development in the UK: Identification and geochemical characterisation of local source emissions of methane to atmosphere. Science of The Total Environment 708, 134600. mobile surveys of methane sources using vehicle-mounted instruments have been performed in the Fylde and Ryedale regions of Northern England over the 2016–19 period around proposed unconventional (shale) gas extraction sites. The aim was to identify and characterise methane sources ahead of hydraulically fractured shale gas extraction in the area around drilling sites. This allows a potential additional source of emissions to atmosphere to be readily distinguished from adjacent sources, should gas production take place.The surveys have used ethane:methane (C2:C1) ratios to separate combustion, thermogenic gas and biogenic sources. Sample collection of source plumes followed by high precision δ13C analysis of methane, to separate and isotopically characterise sources, adds additional biogenic source distinction between active and closed landfills, and ruminant eructations from manure.The surveys show that both drill sites and adjacent fixed monitoring sites have cow barns and gas network pipeline leaks as sources of methane within a 1?km range. These two sources are readily separated by isotopes (δ13C of ?67 to ?58‰ for barns, compared to ?43 to ?39‰ for gas leaks), and ethane:methane ratios (<0.001 for barns, compared to >0.05 for gas leaks). Under a well-mixed daytime atmospheric boundary layer these sources are generally detectable as above baseline elevations up to 100?m downwind for gas leaks and up to 500?m downwind for populated cow barns. It is considered that careful analysis of these proxies for unconventional production gas, if and when available, will allow any fugitive emissions from operations to be distinguished from surrounding sources.Lu, G.-Y., Imai, H., Ikeya, K., Sumida, H., Watanabe, A., 2020. Black carbon as a significant component of aromatic carbon in surface soils and its importance is enhanced in volcanic ash soil profiles. Organic Geochemistry 140, 103957. carbon (BC) constitutes a refractory carbon (C) pool in soil and other environments. Estimating the amount and dynamics of BC in soil is important in terms of the global C cycle. The goal of this study was to characterize the contribution of BC to total and aromatic C in a variety of soils using the benzene polycarboxylic acid (BPCA) method and solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Thirteen A-/Ap (plowed layer)-horizon soils that belong to widely distributed soil series (Humic Andosols, Dystric Cambisols, Gleyic Cambisols, Eutric Fluvisols, and Dystric Planosols) under typical land uses (forest, grassland, upland field, and paddy field) in Japan and two Andosol profiles were analyzed. Three humic acid samples including the green fraction, which contains 4,9-dihydroxyperylene-3,10-quinone (DHPQ) as a chromophore and has mycorrhiza as a possible source (referred to as Pg), were also subjected to the BPCA procedure. The BC content in the 13 A-/Ap-horizon soils was 0.3–53 gC kg?1 or 5.7–48% of the total soil C (BC%). The BC content correlated positively with the total C content and with aromatic C content, while the relationship between BC% and soil order or land use was not clear. An analysis of Pg suggested the potential contribution of DHPQ to the yield of benzenehexacarboxylic acid in the BPCA method. The variations in BC content and C composition of two Andosol profiles indicated a greater stability of BC than the other types of C, including monocyclic aromatic C. The contribution of BC to aromatic C in their lower layers was estimated to be ca. 55–70% based on a regression equation when assuming that 70–90% of the BC was aromatic C.Lu, K.-J., van ’t Wout Hofland, N., Mor, E., Mutte, S., Abrahams, P., Kato, H., Vandepoele, K., Weijers, D., De Rybel, B., 2020. Evolution of vascular plants through redeployment of ancient developmental regulators. Proceedings of the National Academy of Sciences 117, 733-740.: Vascular plants contribute to most of the food and feed production on earth and deliver heating and construction materials in the form of wood. Yet, we know very little about how nonvascular plants acquired vascular tissues during evolution. Here, we provide molecular insights into how 2 evolutionarily conserved transcription factors were redeployed to control proliferation of vascular cells. This is an example of a developmental regulator for which the innovations leading to a vascular function are clearly correlated with the emergence of vascular plants. Thus, while cell division alone is likely not the only driver, it might have been an important evolutionary innovation enabling the emergence of vascular plants.Abstract: Vascular plants provide most of the biomass, food, and feed on earth, yet the molecular innovations that led to the evolution of their conductive tissues are unknown. Here, we reveal the evolutionary trajectory for the heterodimeric TMO5/LHW transcription factor complex, which is rate-limiting for vascular cell proliferation in Arabidopsis thaliana. Both regulators have origins predating vascular tissue emergence, and even terrestrialization. We further show that TMO5 evolved its modern function, including dimerization with LHW, at the origin of land plants. A second innovation in LHW, coinciding with vascular plant emergence, conditioned obligate heterodimerization and generated the critical function in vascular development in Arabidopsis. In summary, our results suggest that the division potential of vascular cells may have been an important factor contributing to the evolution of vascular plants.Lu, T., Li, Z., Hou, D., Xu, Z., Ban, X., Zhou, B., 2020. Experimental and numerical evaluation of surfactant-nanoparticles foam for enhanced oil recovery under high temperature. Energy & Fuels 34, 1005-1013. this article, experiments and simulations were conducted to evaluate performance of surfactant-Nanoparticles foam for enhanced oil recovery under high temperature. Experimentally, the displacement behavior of surfactant-Nanoparticles foam for enhanced oil recovery was studied by micromodel tests at 90 °C. The recovery performance of surfactant-Nanoparticles foam flooding was analyzed by sandpack flooding experiments at 150 °C. Theoretically, a mechanistic model of surfactant-Nanoparticles foam flooding was constructed. The micromodel tests indicate that the surfactant-Nanoparticles foam was more stable than that of the surfactant foam in the porous media at 90 °C. The surfactant-Nanoparticles foam could accumulated in the pores with less oil and increase the swept area. The crude oil could be emulsified into oil droplets by surfactant-Nanoparticles foam which can greatly enhance the oil recovery. The sandpack flooding results show that the surfactant-Nanoparticles foam had better recovery performance at 150 °C. Compared with the surfactant foam, the surfactant-Nanoparticles foam produced from the sandpack flooding experiment had a smaller average particle size and higher sphericity. A mechanistic model of surfactant-Nanoparticles foam flooding was constructed. A good match was achieved between the numerical simulation and sandpack flooding experiments in terms of pressure and oil recovery by adjusting the model parameters. The simulation study indicates that the performance of surfactant- Nanoparticles foam flooding is better than that obtained by surfactant foam flooding under high temperature.Luan, Y., Liu, B., Hao, P., Zhan, K., Liu, J., 2020. Oil displacement by supercritical CO2 in a water cut dead-end pore: Molecular dynamics simulation. Journal of Petroleum Science and Engineering 188, 106899. of residual oils from the micro/nanopores in the reservoir is one perpetual goal of Enhancing oil recovery (EOR), which presents a big challenge for both advanced technologies and fundamental theories. In the current study, we make a comprehensive molecular dynamics (MD) simulation on the displacement process of trapped oils inside a water cut dead-end pore driven by supercritical CO2 molecules. Firstly, the whole displacement process is fully demonstrated by snapshots of MD simulation. Next, the collapse details of the water film between carbon dioxide and octane are simulated, where the hydrogen bonds and the evolution of ruptured hole are discussed. Thirdly, the configuration of the oil-water interface is computed and analyzed by the Laplace equation. Fourthly, the displacement mechanism of octane by carbon dioxide is explained according to the energy principle. These findings can strengthen our understandings on the details of the residual oil displacement in rocks, which may provide some inspirations on the oil recovery enhancement.Lupton, N., Connell, L.D., Heryanto, D., Sander, R., Camilleri, M., Down, D.I., Pan, Z., 2020. Enhancing biogenic methane generation in coalbed methane reservoirs – Core flooding experiments on coals at in-situ conditions. International Journal of Coal Geology 219, 103377. of microbial methanogenesis on intact coal under in-situ conditions is demonstrated in a series of 18 anaerobic core flooding experiments. The experiments used core samples from producing coalbed methane fields in the Surat Basin and Bowen Basin, with formation water containing methanogenic microbial consortia sourced from within the matching basin. The formation water was amended with nutrients containing phosphorus and nitrogen before being used in core flooding experiments of between 6 and 20 weeks duration. Since the core floods used degassed coal core at reservoir pressure, gas generated during the core flood could be adsorbed and retained by the coal. Therefore the quantity of methane generated was determined at the end of the experiment by decreasing the pore pressure and measurement of the volume of gas desorbed from the core sample. The amount of methane generated, averaged on a per week basis, varied considerably across the different core floods but was up to 7.75 μmol methane per gram of coal per week, comparable to previous studies where biostimulation experiments were conducted on crushed coal particles. During the core floods, the nutrient concentration was measured periodically in inflow and outflow water samples and the rates of nutrient consumption determined. The concentration of methane dissolved in the water samples was also determined and used as an indicator during a core flood of the relative rate of methanogenesis. Plateaus in gas generation were observed in the majority of core floods despite constant nutrient supply, indicating nutrient availability is not the single limiting factor to sustained methanogenesis. Higher gas generating core floods displayed higher rates of utilisation of phosphorus, underlining its importance in stimulation of microbial activity, while nutrient utilisation and gas generation measured in the absence of continuous nutrient delivery suggests the possibility of injection and production from a single CBM well. Results demonstrate the ability to stimulate gas generation on intact coal under reservoir conditions, an important step in development of technology for increasing gas content in depleted or undersaturated CBM fields.Ma, X., Meng, L., Zhang, H., Zhou, L., Yue, J., Zhu, H., Yao, R., 2020. Sophorolipid biosynthesis and production from diverse hydrophilic and hydrophobic carbon substrates. Applied Microbiology and Biotechnology 104, 77-100. (SLs), mainly synthesized by yeasts, were a sort of biosurfactant with the highest fermentation level at present. In recent years, SLs have drawn extensive attention for their excellent physiochemical properties and physiological activities. Besides, issues such as economics, sustainability, and use of renewable resources also stimulate the shift from chemical surfactants towards green or microbial-derived biosurfactants. SLs’ large-scale production and application were restricted by the relatively high production costs. Currently, waste streams from agriculture, food and oil refining industries, etc., have been exploited as low-cost renewable substrates for SL production. Advanced cultivation method, uncommonly used substrates, and new genetically modified SL-producing mutants were also designed and applied to improve the productivity or the special properties of SLs. In this review, a systematic and detailed description of primary and secondary metabolism pathways involved in SL biosynthesis was summarized firstly. Furthermore, based on the pathways of SL biosynthesis from different carbon substrates, we reviewed the current knowledge and advances in the exploration of cost-effective and infrequently used hydrophilic and hydrophobic substrates for large or specialized SL production.Ma, Y., Zhang, Y., Zhang, R., Guan, F., Hou, B., Duan, J., 2020. Microbiologically influenced corrosion of marine steels within the interaction between steel and biofilms: a brief view. Applied Microbiology and Biotechnology 104, 515-525. is the harshest corrosive environment where almost all marine underwater equipment and facilities undergo corrosion caused by marine microorganisms. With the development of marine resources globally, the marine engineering and relevant infrastructures have increased exponentially. Microbiologically influenced corrosion (MIC) leads to severe safety accidents and great economic losses. The specific aggregation of corrosive microbial communities and their interactions with materials conform to a typical ecological adaptation mechanism. On the one hand, corrosive biofilms in the marine environment selectively colonize on a specific steel substrate by utilizing their complex community composition and various extracellular polymeric substances; on the other hand, the elemental composition and surface microstructure of different engineering steels affect the microbial community and corrosive process. MIC in the marine environment is a dynamic process evolving with the formation of corrosive biofilms and corrosion products. In this mini-review, the interactions between corrosive biofilm and steel substrates are explored and discussed, especially those conducted in situ in the marine environment. Herein, the important role of iron in the dynamic process of marine corrosion is highlighted.MacKenzie, M.D., Dietrich, S.T., 2020. Atmospheric sulfur and nitrogen deposition in the Athabasca oil sands region is correlated with foliar nutrient levels and soil chemical properties. Science of The Total Environment 711, 134737. oil extraction industry and human activity in north eastern Alberta has been growing steadily since the 1960’s and is a source of air pollution. In the late 1990’s the Wood Buffalo Environmental Association was established to monitor air quality for both public and environmental health. A primary environmental concern was soil acidification caused by sulfur (S) and nitrogen (N) deposition. A network of forest health monitoring (FHM) sites was established in dry jack pine ecosystems to serve as an early indicator of negative impacts. A sampling campaign was executed in 2011 and this study examines soil properties and foliar nutrients in the context of measured and modeled acid deposition. Total N (TN), SO42?, pH, base cation to aluminum ratio (BC:Al), and base saturation (% BS) are reported for the organic layer (LFH) and 3 depths in the mineral soil, while foliar nutrients were analysed from current annual growth in jack pine needles. Atmospheric deposition of S, N, BC, and potential acid input (PAI) in the study area was recently provided by Edgerton et al. (2020) and soil and foliar chemistry was evaluated based on deposition estimates and measurements. Inverse distance weighting was used to examine spatial patterns and regression analysis was used to quantify relationships between variables. The results indicated that S deposition is spatially correlated with foliar SO42? concentration, and LFH SO42?, but not mineral topsoil (0–5?cm) SO42?. Nitrogen deposition was spatially correlated with foliar N concentration, but not LFH or topsoil TN indicating potential uptake by the foliage or rapid uptake by roots in the LFH layer. High BC deposition in the same areas with the highest potential acid inputs (PAI) did not correlate significantly with changes in soil pH. However, LFH pH was significantly related to dry NH3 deposition, which has not been reported previously and requires further investigation.Maddahian, R., Farsani, A.T., Ghorbani, M., 2020. Numerical investigation of asphaltene fouling growth in crude oil preheat trains using multi-fluid approach. Journal of Petroleum Science and Engineering 188, 106879. this study, the asphaltene deposition and the fouling layer growth are modeled using the multi-fluid approach. The crude oil is considered as a multi-species fluid which the asphaltene species can deposit on the heat transfer surfaces due to the volume reaction. The effective mechanisms of asphaltene particle transport are the molecular and eddy diffusions. Therefore the species modeling approach is utilized for particles transport by diffusion processes in the carrier phase. To model the fouling layer growth without considering an initial thickness for the deposited layer, extra terms are added to the momentum equations of primary and secondary phases. The results of the numerical model are validated against available experimental data and a good agreement is seen. Finally, the developed model is applied for a specific case and the effect of fouling layer growth on the fluid velocity, the temperature variations, and the heat transfer rate are investigated. The results show that the heat transfer rate decreases during the fouling and the developed model could predict accurately the physics of fouling layer growth.Mahmoud, M., Hamza, A., Hussein, I.A., Eliebid, M., Kamal, M.S., Abouelresh, M., Shawabkeh, R., Al-Marri, M.J., 2020. Carbon dioxide EGR and sequestration in mature and immature shale: Adsorption study. Journal of Petroleum Science and Engineering 188, 106923., CO2 sequestration in different shale formations has become an attractive option owing to the abundance of shale basins. However, these formations have different maturity levels and contain a variety of minerals such as carbonates and clays. The amount of CO2 in shale formations is related to the adsorption capacity of these rocks. In this work, adsorption of CH4 and CO2 on three different shales (mature and immature) is studied at different temperatures (50 °C–150 °C). Increasing the percentage of CO2 in the gas mixture raised the adsorption capacity. The different shale samples behave differently at different temperatures. Two of the investigated shale samples (low and moderate total organic carbon (TOC)) showed an endothermic response from 50 °C to 100 °C with a tremendous increase in the adsorption capacity followed by an exothermic response and significant reduction in the capacity at 150 °C. The third sample, which had the highest TOC, had no CH4 adsorption at 50 °C but showed an endothermic response at high temperature with a significant increase in CH4 adsorption. This temperature dependent adsorption behavior is linked to thermally induced alterations in the crystallinity of clay minerals and the organic material. The thermodynamic analysis reveals that the investigated shales have a high affinity to CO2, while adsorption entropy and enthalpy were less compared to CH4. The adsorption isotherms reveal that adsorption of CH4 and CO2 on the shale best modeled by Freundlich isotherm due to surface heterogeneity of the shale and by BET isotherms due to pore filling at high pressure values.Mahmoud, M., Hussein, I., Carchini, G., Shawabkeh, R., Eliebid, M., Al-Marri, M.J., 2019. Effect of rock mineralogy on Hot-CO2 injection for enhanced gas recovery. Journal of Natural Gas Science and Engineering 72, 103030. gas reservoirs are one of the viable options for CO2 enhanced gas recovery and sequestration. Injection of hot CO2 into depleted reservoirs is expected to improve gas recovery. Static adsorption and core flooding experiments were performed to quantify methane/CO2 adsorption/desorption using different rocks at different temperatures and pressures. Rocks such as shale, tight sandstone, calcite, and dolomite were used. For calcite, theoretical simulations were performed. Though methane desorption has increased when the temperature was raised, the results suggest that the gas recovery has doubled when the temperature has been increased from 50° to 100?°C in conventional reservoirs and from 100° to 150?°C in conventional and unconventional reservoirs. Similar trends were obtained for different rocks with increasing temperature. Core flooding and static adsorption experiments showed matching results. Rock mineralogy affects the adsorption capacity of the rock with shale rock having a 60% higher methane production than sandstone.Maillard, J., Hupin, S., Carrasco, N., Schmitz-Afonso, I., Gautier, T., Afonso, C., 2020. Structural elucidation of soluble organic matter: Application to Titan's haze. Icarus 340, 113627. origin and evolution of organic matter in the solar system intertwines astrobiology and planetary geochemistry issues. To observe the contribution of atmospheric processes in the formation of complex organic matter, one of the most intensively studied objects in the outer solar system is Titan, the largest moon of Saturn. Its reducing atmosphere of methane and nitrogen hosts a thick, permanent, nitrogen-rich, organic haze, whose complex composition remains largely unknown. Due to the measurement of species at large mass-to-charge ratio and infrared information from the Cassini-Huygens mission, polyaromatic hydrocarbons (PAHs) based structure for this haze has been suggested. Here, we propose a snapshot of the global chemical structure based on the analysis of laboratory analogue of Titan's haze with ion mobility spectrometry coupled with mass spectrometry. This robust analysis, validated with other geochemical complex mixtures, such as petroleum, allows for the observation of the size and three-dimensional structure of detected species. By comparison, with standards molecules, we exclude several structures such as pure PolyHCN and pure polycyclic aromatic hydrocarbons to be present in the principal trend of the laboratory tholins. Using theoretical calculations, we propose a plausible structure consistent with our results, which is a branched triazine-pyrazole. We observe that the larger the aerosols molecules are, the more they tend towards a structure containing small aromatics cores linked together by short chains. We suggest that the use of such an analytical approach could help advance our understanding of other complex organic compounds in the Solar System such as soluble organic matter in meteorites.Manda, S., Punekar, J., 2020. Experimental validation of the planktic foraminifera fragmentation index as proxy for the end-Cretaceous Ocean Acidification. Marine Micropaleontology 155, 101821. final ~50 ky of the Maastrichtian leading up to the Cretaceous-Paleogene (K-Pg) boundary mass extinction at Bidart (France) and Gamsbach (Austria) record poor carbonate preservation indicative of ocean acidification preceding the mass extinction. Further evidence includes enhanced planktic foraminifera test fragmentation, anomalously low bulk-rock magnetic susceptibility (acidification) and peak mercury content (toxicity) related to peak Deccan volcanism in India. Here we present new experimental data that validates the Fragmentation Index of planktic foraminifera as a reliable proxy for the end-Cretaceous acidification.Pristine Cretaceous planktic foraminiferal shells (from DSDP 525A, palaeodepth ~1000 m) were exposed to buffers of pH 8.0, 7.5, 7.0 and 6.5 for 15 days each, and their preservation state was quantified as a function of time. The critical variables affecting test taphonomy are morphology, pH and time of exposure. Thin-walled fragile biserial species constitute an average ~60% of typical Late Maastrichtian assemblages (e.g Heterohelix globulosa and H. planata) and are most susceptible to dissolution, followed by simple coiled forms such as Rugoglobigerina sp. (~19% of the assemblage) and Hedbergella sp. (~6% of the assemblage). The globotruncanids (Globotruncana, Globotruncanita, ~12%) are least susceptible to chemical and physical damage. Lower pH conditions render tests more vulnerable to physical fragmentation. Caution is needed to assess taphonomic inflation of morphologically robust yet environmentally sensitive Cretaceous species (e.g. globotruncanids), that may result in an underestimation of the degree/nature of the faunal crisis and tempo of extinctions in the pre-extinction acidification interval.Mansoori Mosleh, F., Mortazavi, Y., Hosseinpour, N., Khodadadi, A.A., 2020. Asphaltene adsorption onto carbonaceous nanostructures. Energy & Fuels 34, 211-224. adsorption of asphaltene onto different carbonaceous nanostructures including reduced graphene oxide (rGO), multiwall carbon nanotubes (MWCNTs), carbon black (CB), and activated carbon (AC) was studied. Graphene oxide was synthesized via Hummers’ method and reduced in a thermal shock to prepare rGO. Asphaltene was extracted from a heavy oil sample and characterized. The textural and structural properties of the carbonaceous nanostructures were characterized by Brunauer–Emmet–Teller surface area measurement, field-emission scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and temperature-programmed desorption. Asphaltene was dissolved in a solution of 37 vol % heptane in toluene (Heptol) to prepare heavy oil model solutions. The carbonaceous nanostructures were added to the model oils, and the kinetics as well as the equilibrium adsorption and desorption of the asphaltene onto the adsorbents were studied. The pseudo-second-order kinetic model best explains the asphaltene adsorption onto the carbonaceous adsorbents. The time required to approach equilibrium adsorption of the asphaltene is 1, 4, 12, and 24 h over rGO, MWCNTs, CB, and AC, respectively. The adsorption isotherm of the asphaltene onto rGO follows Langmuir model, while Freundlich isotherm bets fits the asphaltene equilibrium adsorption onto MWCNTs and CB. Among the carbonaceous adsorbents, the rGO sample exhibits the highest asphaltene adsorption capacity of 640 mg/g, about 5.7, 2.4, and 1.2 times as high as that of AC, CB, and MWCNTs, respectively. The adsorption of the asphaltene onto AC is found to be diffusion-limited. This is ascribed to the micropores present in the AC structure. Water content of the model oils has no effects on the asphaltene adsorption capacity of the carbonaceous adsorbents. The heat of adsorption of the asphaltene is calculated to be in the range of ?11.51 to ?22.49 kJ/mol, indicating strong and nearly irreversible polar, π–π, and π–polar interactions of the asphaltene with the surface sites of the carbonaceous nanostructures.Marcone, G.L., Rosini, E., Crespi, E., Pollegioni, L., 2020. D-amino acids in foods. Applied Microbiology and Biotechnology 104, 555-574. the only exception of glycine, all amino acids exist in two specular structures which are mirror images of each other, called D-(dextro) and L-(levo) enantiomers. During evolution, L-amino acids were preferred for protein synthesis and main metabolism; however, the D-amino acids (D-AAs) acquired different and specific functions in different organisms (from playing a structural role in the peptidoglycan of the bacterial cell wall to modulating neurotransmission in mammalian brain). With the advent of sophisticated and sensitive analytical techniques, it was established during the past few decades that many foods contain considerable amounts of D-AAs: we consume more than 100?mg of D-AAs every day. D-AAs are present in a variety of foodstuffs, where they fulfill a relevant role in producing differences in taste and flavor and in their antimicrobial and antiaging properties from the corresponding L-enantiomers. In this review, we report on the derivation of D-AAs in foods, mainly originating from the starting materials, fermentation processes, racemization during food processing, or contamination. We then focus on leading-edge methods to identify and quantify D-AAs in foods. Finally, current knowledge concerning the effect of D-AAs on the nutritional state and human health is summarized, highlighting some positive and negative effects. Notwithstanding recent progress in D-AA research, the relationships between presence and nutritional value of D-AAs in foods represent a main scientific issue with interesting economic impact in the near future.Marone, F., Schlepütz, C.M., Marti, S., Fusseis, F., Velásquez-Parra, A., Griffa, M., Jiménez-Martínez, J., Dobson, K.J., Stampanoni, M., 2020. Time resolved in situ X-ray tomographic microscopy unraveling dynamic processes in geologic systems. Frontiers in Earth Science 7, 346. doi: 10.3389/feart.2019. 00346. tomographic microscopy is a well-established analysis technique in different fields of the Earth Sciences to access volumetric information of the internal microstructure of a large variety of opaque materials with high-spatial resolution and in a non-destructive manner. Synchrotron radiation, with its coherence and high flux, is required for pushing the temporal resolution into the second and sub-second regime and beyond, and therefore moving from the investigation of static samples to the study of fast dynamic processes as they happen in 3D. Over the past few years, several hardware and software developments at the TOMCAT beamline at the Swiss Light Source contributed to establishing its highly flexible and user-friendly fast tomography endstation, making a large variety of new dynamic in situ and operando investigations possible. Here we present an overview of the different devices, including an in-house developed detector, a new highly efficient macroscope and a programmable fast rotation stage. Their tight interplay and synchronization are key for lifting experimental design compromises and follow dynamic processes with high spatial and temporal resolution unfolding over prolonged periods of time, as often required by many applications. We showcase these new capabilities for the Earth Sciences community by presenting three different geological studies, which make use of different sample environments. With a tri-axial deformation rig, chemo-mechanical-hydraulic feedbacks between gypsum dehydration and halite deformation have been studied, while the spatio-temporal evolution of a solute plume has been investigated for the first time in 3D with a flow cell. A laser-based heating system available at the beamline provides access to the high temperatures required to address bubble growth and collapse as well as bubble-bubble interaction and coalescence in volcanological material. With the integration of a rheometer, information on bubble deformation could also be gained. In the near future, upgrades of most large-scale synchrotron radiation facilities to diffraction-limited storage rings will create new opportunities, for instance through sub-second tomographic imaging capabilities at sub-micron length scales.Martín-Cabello, G., Terrón-González, L., Ferrer, M., Santero, E., 2020. Identification of a complete dibenzothiophene biodesulfurization operon and its regulator by functional metagenomics. Environmental Microbiology 22, 91-106. screening for aromatic ring oxygenases of an oil contaminated soil metagenome identified 25 different clones bearing monooxygenases coding genes. One fosmid bore an operon containing four tightly linked genes coding for a complete dibenzothiophene biodesulfurization pathway, which included the predicted monooxygenases DszC and DszA, the desulfinase DszB, and an FMN‐oxidoreductase designated DszE. The dszEABC operon provided Escherichia coli with the ability to use dibenzothiophene as the only sulfur source. Transcription of the operon is driven from a σN‐dependent promoter and regulated by an activator that was designated dszR. DszR has been purified and characterized in vitro and shown to be a constitutively active σN‐dependent activator of the group IV, which binds to two contiguous sequences located upstream of the promoter. The dsz promoter and dszE and dszR genes have apparently been recruited from an aliphatic sulfonate biodegradation pathway. If transcribed from a heterologous upstream promoter, the σN‐dependent promoter region functions as an ‘insulator’ that prevents translation of dszE, by binding with its ribosome binding site. Translational coupling, in turn, prevents translation of the downstream dszABC genes. The silencer combined with translational coupling thus represents an effective way of preventing expression of operons when spuriously transcribed from upstream promoters.Martínez, L., Santoro, G., Merino, P., Accolla, M., Lauwaet, K., Sobrado, J., Sabbah, H., Pelaez, R.J., Herrero, V.J., Tanarro, I., Agúndez, M., Martín-Jimenez, A., Otero, R., Ellis, G.J., Joblin, C., Cernicharo, J., Martín-Gago, J.A., 2020. Prevalence of non-aromatic carbonaceous molecules in the inner regions of circumstellar envelopes. Nature Astronomy 4, 97-105. stars are foundries of chemical complexity, gas and dust that provide the building blocks of planets and life, and dust nucleation first occurs in their photosphere. The circumstellar regions enveloping these stars, despite their importance, remain hidden to many observations, and dust formation processes are therefore still poorly understood. Laboratory astrophysics provides complementary routes to unveil these chemical processes, but most experiments rely on combustion or plasma decomposition of molecular precursors under physical conditions far removed from those in space. To reproduce and characterize the bottom-up dust formation process, we have built an ultra-high vacuum machine combining atomic gas aggregation with advanced in situ characterization techniques. We show that carbonaceous dust analogues that formed from low-pressure gas-phase condensation of carbon atoms in a hydrogen atmosphere, in a ratio of carbon to molecular hydrogen similar to that reported for evolved stars, lead to the formation of amorphous carbon nanograins and aliphatic carbon clusters. Aromatic species and fullerenes do not form effectively under these conditions, raising implications for a revision of the chemical mechanisms taking place in circumstellar envelopes.Martins, L.L., Schulz, H.-M., Severiano Ribeiro, H.J.P., Nascimento, C.A.d., Souza, E.S.d., Cruz, G.F.d., 2020. Cadalenes and norcadalenes in organic-rich shales of the Permian Irati Formation (Paraná Basin, Brazil): Tracers for terrestrial input or also indicators of temperature-controlled organic-inorganic interactions? Organic Geochemistry 140, 103962., isocadalene and a series of norcadalenes were identified in black shales of the Permian Irati Formation in the northeastern and central eastern Paraná Basin (Brazil). The origin of their α-isomers with an isopropyl substituent is potentially related to higher plants, and likely reflects the spreading of pteridophytes and gymnosperms after the glaciation of southern Gondwana. A general increase in the relative abundance of isocadalene (1,6-dimethyl-3-isopropylnaphthalene, the β-isomer) co-occurs in with increasing thermal maturity at the base of the Amaral Machado Quarry (northeastern basin), and refers to the acid-catalyzed rearrangement of cadalene (1,6-dimethyl-4-isopropylnaphthalene, the α-isomer) due to the presence of montmorillonite, via an organic-inorganic interaction. This localized and incipient maturation can be related to diabase sills of the Serra Geral Formation. Similar maturation due to heating also affected the distribution of the norcadalenes by thermally stabilizing their α-isomers with an isopropyl substituent, in addition to the formation of related compounds with an ethyl substituent. Based on this, a norcadalene ratio is proposed, which is the sum of the 1,6-dimethyl-4-ethylnaphthalene and 1,6-dimethyl-3-ethylnaphthalene over the sum of the 1-isopropyl-4-methylnaphthalene and 1-isopropyl-7-methylnaphthalene. The results of this ratio and the established cadalene ratio resemble each other whereas samples from the S?o Mateus do Sul Quarry (central eastern basin) were not affected by thermal maturation and are characterized by a uniform distribution of the cadalenes and norcadalenes.Martins, L.L., Schulz, H.-M., Severiano Ribeiro, H.J.P., Nascimento, C.A.d., Souza, E.S.d., Cruz, G.F.d., 2020. Organic geochemical signals of freshwater dynamics controlling salinity stratification in organic-rich shales in the Lower Permian Irati Formation (Paraná Basin, Brazil). Organic Geochemistry 140, 103958. Lower Permian Irati Formation in the northeastern and central eastern Paraná Basin (southern Brazil) was investigated in terms of bulk and molecular organic geochemistry in order to enlighten the complex depositional paleoenvironment during deposition of Irati black shales. The geochemical data reflect temporal and spatial variations of freshwater incursions promoting salinity stratification and high primary productivity in surface waters with the establishment of photic zone euxinia. Overall, highly concentrated C17 long-chain alkylnaphthalenes point to algal blooms as a result of freshwater inflows into the Irati Sea, mostly in the central eastern basin segment, and resemble concentration variations of pristane, phytane and nC17. The freshwater inflows were also retraced by increasing chroman ratios toward the top of the investigated units along with the general decrease of further palaeosalinity indicators, e.g., gammacerane, tetracyclic (C24), β-carotane, and the herein suggested γ-carotane and lexane indexes. The existence of a water column stratification promoting organic matter preservation is supported by the detection of tetrahydrophenanthrene at high concentrations, in addition to the known prominent occurrence of gammacerane. The detection of C10 to C31 aryl isoprenoids in addition to C16 and C18 pseudohomologue aryl isoprenoids points to the presence of photic zone euxinia. In general, samples from the central eastern basin were deposited in a deeper marine setting with lower salinity than samples from the northeastern basin, which displays signals of a shallower marine environment with reducing bottom water conditions, both deposited under freshwater influxes.Ma?mig, M., Lüdke, J., Krahmann, G., Engel, A., 2020. Bacterial degradation activity in the eastern tropical South Pacific oxygen minimum zone. Biogeosciences 17, 215-230. minimum zones (OMZs) show distinct biogeochemical processes that relate to microorganisms being able to thrive under low or even absent oxygen. Microbial degradation of organic matter is expected to be reduced in OMZs, although quantitative evidence is low. Here, we present heterotrophic bacterial production (3H leucine incorporation), extracellular enzyme rates (leucine aminopeptidase/β-glucosidase) and bacterial cell abundance for various in situ oxygen concentrations in the water column, including the upper and lower oxycline, of the eastern tropical South Pacific off Peru. Bacterial heterotrophic activity in the suboxic core of the OMZ (at in situ?≤?5??mol?O2?kg?1) ranged from 0.3 to 281??mol?C?m?3?d?1 and was not significantly lower than in waters of 5–60??mol?O2?kg?1. Moreover, bacterial abundance in the OMZ and leucine aminopeptidase activity were significantly higher in suboxic waters compared to waters of 5–60??mol?O2?kg?1, suggesting no impairment of bacterial organic-matter degradation in the core of the OMZ. Nevertheless, high cell-specific bacterial production was observed in samples from oxyclines, and cell-specific extracellular enzyme rates were especially high at the lower oxycline, corroborating earlier findings of highly active and distinct micro-aerobic bacterial communities. To assess the impact of bacterial degradation of dissolved organic matter (DOM) for oxygen loss in the Peruvian OMZ, we compared diapycnal fluxes of oxygen and dissolved organic carbon (DOC) and their microbial uptake within the upper 60?m of the water column. Our data indicate low bacterial growth efficiencies of 1?%–21?% at the upper oxycline, resulting in a high bacterial oxygen demand that can explain up to 33?% of the observed average oxygen loss over depth. Our study therewith shows that microbial degradation of DOM has a considerable share in sustaining the OMZ off Peru.Mateo, P., Keller, G., Adatte, T., Bitchong, A.M., Spangenberg, J.E., Vennemann, T., Hollis, C.J., 2019. Deposition and age of Chicxulub impact spherules on Gorgonilla Island, Colombia. GSA Bulletin 132, 215-232. end-Cretaceous mass extinction (66 Ma) has long been associated with the Chicxulub impact on the Yucatan Peninsula. However, consensus on the age of this impact has remained controversial because of differing interpretations on the stratigraphic position of Chicxulub impact spherules relative to the mass extinction horizon. One side argues that the impact occurred precisely at the Cretaceous-Paleogene boundary, thus coinciding with the mass extinction; the other side argues that the impact predated the Cretaceous-Paleogene boundary, based on the discovery of primary impact spherules deposits in NE Mexico and Texas near the base of planktic foraminiferal zone CF1, dated at 170 k.y. before the Cretaceous-Paleogene boundary. A recent study of the most pristine Chicxulub impact spherules discovered on Gorgonilla Island, Colombia, suggested that they represent a primary impact deposit with an absolute age indistinguishable from the Cretaceous-Paleogene boundary. Here, we report on the Gorgonilla section with the main objective of evaluating the nature of deposition and age of the spherule-rich layer relative to the Cretaceous-Paleogene boundary.The Gorgonilla section consists of light gray-yellow calcareous siliceous mudstones (pelagic deposits) alternating with dark olive-brown litharenites (turbidites). A 3-cm-thick dark olive-green spherule-rich layer overlies an erosional surface separating Maastrichtian and Danian sediments. This layer consists of a clast-supported, normally graded litharenite, with abundant Chicxulub impact glass spherules, lithics (mostly volcanic), and Maastrichtian as well as Danian microfossils, which transitions to a calcareous mudstone as particle size decreases. Mineralogical analysis shows that this layer is dominated by phyllosilicates, similar to the litharenites (turbidites) that characterize the section. Based on these results, the spherule-rich layer is interpreted as a reworked early Danian deposit associated with turbiditic currents. A major hiatus (>250 k.y.) spanning the Cretaceous-Paleogene boundary and the earliest Danian is recorded at the base of the spherule-rich layer, based on planktic foraminiferal and radiolarian biostratigraphy and carbon stable isotopes. Erosion across the Cretaceous-Paleogene boundary has been recorded worldwide and is generally attributed to rapid climate changes, enhanced bottom-water circulation during global cooling, sea-level fluctuations, and/or intensified tectonic activity. Chicxulub impact spherules are commonly reworked and redeposited into younger sediments overlying a Cretaceous-Paleogene boundary hiatus of variable extent in the Caribbean, Central America, and North Atlantic, while primary deposits are rare and only known from NE Mexico and Texas. Because of their reworked nature, Gorgonilla spherules provide no stratigraphic evidence from which the timing of the impact can be inferred.Matsu’ura, S., Kondo, M., Danhara, T., Sakata, S., Iwano, H., Hirata, T., Kurniawan, I., Setiyabudi, E., Takeshita, Y., Hyodo, M., Kitaba, I., Sudo, M., Danhara, Y., Aziz, F., 2020. Age control of the first appearance datum for Javanese Homo erectus in the Sangiran area. Science 367, 210-214.: The chronology of the World Heritage Site of Sangiran in Indonesia is crucial for the understanding of human dispersals and settlement in Asia in the Early Pleistocene (before 780,000 years ago). It has been controversial, however, especially regarding the timing of the earliest hominin migration into the Sangiran region. We use a method of combining fission-track and uranium-lead dating and present key ages to calibrate the lower (older) Sangiran hominin-bearing horizons. We conclude that the first appearance datum for the Sangiran hominins is most likely ~1.3 million years ago and less than 1.5 million years ago, which is markedly later than the dates that have been widely accepted for the past two decades.Editor's summary: Dating the arrival of the first hominins in Java. The World Heritage archaeological site at Sangiran on the island of Java in Indonesia has major importance for the understanding of human arrival and evolution in Asia. However, the timing of the first appearance of Homo erectus at the site has been controversial. Using a combination of dating techniques for hominin-bearing sediments, Matsu'ura et al. resolved the arrival of H. erectus at ～1.3 million years ago (see the Perspective by Brasseur). This dating suggests that the earliest hominins in Sangiran are at least 200,000 years younger than has been thought and may represent an important step to the resolution of the controversy.Matsui, H., Jia, J., Tsuji, T., Liang, Y., Masuda, Y., 2020. Microsecond simulation study on the replacement of methane in methane hydrate by carbon dioxide, nitrogen, and carbon dioxide–nitrogen mixtures. Fuel 263, 116640. of methane (CH4) in CH4 hydrate by carbon dioxide (CO2) can enable recovery of CH4, which is a potential future energy resource, while sequestering CO2 to mitigate the effects of global warming. However, little work has been done to address the effects of impurities on CO2 replacement, and the detailed mechanisms. Here, microsecond molecular dynamics simulations were performed to understand the influence of nitrogen (N2) gas on the process of replacing CH4 in CH4 hydrate with CO2 at 280?K and 6?MPa. The results show that CO2 molecules can penetrate more deeply into CH4 hydrate phase when it is mixed with N2. This is mainly because N2 can favor the decomposition of CH4 hydrate and expand the replacement area of CH4 by guest molecules. We confirm that the replacement of CH4 by CO2 and N2 preferably occurs in large and small cages, respectively. In most cases, a mixture hydrate reforms at the outmost layer of the hydrate surface. The CO2/N2 mixture shows an overall higher replacement efficiency than pure CO2 case. Our work demonstrates that CH4 recovery by CO2 injection in CH4 hydrate can be facilitated by N2. The penetration depth of replacement is sensitive to the ratio of N2 to CO2. The knowledge obtained in this study will be helpful for the effective utilization of CO2/N2 mixtures to maximize the recovery percentage of CH4 from hydrate.Maus, D., Heinz, J., Schirmack, J., Airo, A., Kounaves, S.P., Wagner, D., Schulze-Makuch, D., 2020. Methanogenic Archaea can produce methane in deliquescence-driven Mars analog environments. Scientific Reports 10, 6. current understanding of the Martian surface indicates that briny environments at the near-surface are temporarily possible, e.g. in the case of the presumably deliquescence-driven Recurring Slope Lineae (RSL). However, whether such dynamic environments are habitable for terrestrial organisms remains poorly understood. This hypothesis was tested by developing a Closed Deliquescence System (CDS) consisting of a mixture of desiccated Martian Regolith Analog (MRA) substrate, salts, and microbial cells, which over the course of days became wetted through deliquescence. The methane produced via metabolic activity for three methanogenic archaea: Methanosarcina mazei, M. barkeri and M. soligelidi, was measured after exposing them to three different MRA substrates using either NaCl or NaClO4 as a hygroscopic salt. Our experiments showed that (1) M. soligelidi rapidly produced methane at 4?°C, (2) M. barkeri produced methane at 28?°C though not at 4?°C, (3) M. mazei was not metabolically reactivated through deliquescence, (4) none of the species produced methane in the presence of perchlorate, and (5) all species were metabolically most active in the phyllosilicate-containing MRA. These results emphasize the importance of the substrate, microbial species, salt, and temperature used in the experiments. Furthermore, we show here for the first time that water provided by deliquescence alone is sufficient to rehydrate methanogenic archaea and to reactivate their metabolism under conditions roughly analogous to the near-subsurface Martian environment.Mayhew, L.E., Ellison, E.T., 2020. A synthesis and meta-analysis of the Fe chemistry of serpentinites and serpentine minerals. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20180420. iron chemistry of serpentinites and serpentine group minerals is often invoked as a record of the setting and conditions of serpentinization because Fe behaviour is influenced by reaction conditions. Iron can be partitioned into a variety of secondary mineral phases and undergo variable extents of oxidation and/or reduction during serpentinization. This behaviour influences geophysical, geochemical and biological aspects of serpentinizing systems and, more broadly, earth systems. Iron chemistry of serpentinites and serpentines is frequently analysed and reported for single systems. Interpretations of the controls on, and the implications of, Fe behaviour drawn from a single system are often widely extrapolated. There is a wealth of serpentinite/serpentine chemical composition data available in the literature. Consequently, compilation of a database including potential predictors of Fe behaviour and measures of Fe chemistry enables systematic investigation of trends in Fe behaviour across a variety of systems and conditions. The database presented here contains approximately 2000 individual data points including both bulk rock and serpentine mineral geochemical data which are paired whenever possible. Measures of total Fe and Fe oxidation state, which are more limited, are compiled with characteristics of the systems from which they were sampled. Observations of trends in Fe chemistry in serpentinites and serpentines across the variety of geologic systems and parameters will aid in verifying and strengthening interpretations made on the basis of Fe chemistry.Mayr, M.J., Zimmermann, M., Dey, J., Wehrli, B., Bürgmann, H., 2020. Lake mixing regime selects methane-oxidation kinetics of the methanotroph assemblage. Biogeosciences Discussions 2020, 1-15. freshwater lakes, large amounts of methane are produced in anoxic sediments. Methane-oxidizing bacteria effectively convert this potent greenhouse gas into biomass and carbon dioxide. These bacteria are present throughout the water column where methane concentrations can range from nanomolar to millimolar concentrations. In this study, we tested the hypothesis that methanotroph assemblages in seasonally stratified lakes are adapted to the contrasting methane concentrations in the epi- and hypolimnion. We further hypothesized that lake overturn would change the methane oxidation kinetics as more methane becomes available in the epilimnion. Together with the change of methane oxidation kinetics, we investigated changes in the transcription of genes encoding methane monooxygenase, the enzyme responsible for the first step of methane oxidation, with metatranscriptomics. We show that the half-saturation constant (Km) for methane, obtained from laboratory experiments with the natural microbial community, differed by two orders of magnitude between epi- and hypolimnion during stable stratification. During lake overturn, however, the kinetic constants in the epi- and hypolimnion converged along with a change of the transcriptionally active methanotroph assemblage. Conventional particulate methane monooxygenase appeared to be responsible for methane oxidation under different methane concentrations. Our results suggest that methane availability is important for creating niches for methanotroph assemblages with well-adapted methane-oxidation kinetics. This rapid selection and succession of adapted lacustrine methanotroph assemblages allows high methane removal efficiency of more than 90?% to be maintained even under rapidly changing conditions during lake overturn. Consequently, only a small fraction of methane stored in the anoxic hypolimnion is emitted to the atmosphere.McCaig, A.M., Früh-Green, G.L., Kelemen, P., Teagle, D.A.H., 2020. Serpentinite in the Earth system. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20190332.. 0332Olivine ((MgFe)2SiO4) is the most abundant mineral in the upper mantle, which together with the crust comprises the upper 660?km of Earth. It is also a major component of stony meteorites and planetary bodies including Icy Worlds. When olivine comes into contact with water at temperatures less than 500°C, it alters to serpentine (Mg,Fe)3Si2O5(OH)4. This hydration reaction is often accompanied by a redox reaction producing Fe3+ from Fe2+, and H2 from water. H2 is the first building block of life, and hence there is much attention on environments where H2 and organic compounds can be produced abiotically.Serpentine is also important in the Earth system in several other ways: it is a much weaker mineral than olivine and can facilitate slip on faults. Dehydration of serpentine increases pore water pressure and reduces normal stress on faults, leading to earthquakes in subducting slabs. Dehydration water from serpentine is released into the asthenospheric mantle wedge above the subducting slab, reducing the melting point and causing island arc volcanism. Finally, serpentine can be preserved to considerable depths in subducting slabs and may transfer water to other hydrous minerals where it can be recycled into the deep mantle.Active serpentinization is thought to be occurring in a number of modern environments: 1. In the flow system of submarine vent fields such as the Lost City Hydrothermal Field (LCHF) on the Atlantis Massif west of the Mid-Atlantic Ridge. This is venting alkaline fluids rich in H2, CH4, alkanes and carboxylic acids at temperatures of 40–90°C, and is thought to have been active for at least 100?000 years. Large carbonate-brucite chimneys host microbial communities. Several papers in this volume use data from the Atlantis Massif and the LCHF.2. A second submarine environment is the forearc region of subduction zones where fluid released from down dragged sediments and hydrated ocean crust is released into the overlying mantle. A famous example is the Marianas arc, where huge serpentine ‘volcanos' formed of serpentine mud derived from depths up to 20?km are a major bathymetric feature. These volcanos vent low temperature, high pH fluids rich in H2. Fryer et al. [1] review the results of IODP (International Ocean Discovery Program) expeditions and dredging and highlight the effect of seamount subduction in dragging shallow material to depth and perhaps introducing microbes into deep low-temperature environments.3. The other main environment is subaerial exposure of mantle rocks in ophiolite complexes; in particular, the Oman ophiolite which is famous for highly alkali blue pools. This has recently been the focus of the International Continental Scientific Drilling Program (ICDP) Oman Drilling Project that included drilling boreholes into an active subsurface hydrological system where active serpentinization appears to be occurring at low temperatures due to the presence of H2, high pH and strongly reducing fluids. De Obeso & Kelemen [2] detail alteration in Oman peridotite exposed to low-temperature (60°C) serpentinization, with steep gradients in fO2 and fS2 recorded in mineral assemblages. Such gradients can provide energy for microbial life.Several contributors focus on experimental and mineralogical studies of the generation of H2 and CH4, and on the extent of redox reactions during serpentinization. McCollom et al. [3] detail experiments showing that reaction rates of serpentinization and hydrogen generation are increased under high pH conditions typical of low and moderate temperature serpentinization systems. Grozveya et al. [4] highlight the role of fluid inclusions in olivine as microreactors in natural samples. Fluid inclusions are inferred to have been originally aqueous with dissolved CO2 but now contain serpentine and oxide solid precipitates, with the water consumed and replaced by H2- and CH4-rich fluids. These authors suggest that scavenging of H2 and CH4 from fluid inclusions is an alternative source for these components in hydrothermal fluids, compared to the normal assumption of ongoing redox reactions along the flow path. Mayhew [5] reviews the oxidation state of bulk rock serpentinite and the mineral serpentine in samples from a range of environments, as listed above. Serpentinization is invariably accompanied by an increase in Fe3+ concentrations and Fe3+/Fe2+ ratios. In recent years with the replacement of wet chemical analysis by XRF and ICP-OES/MS, determination of the oxidation state of iron in geochemical analyses has not been routine. This type of measurement has the potential to allow quantification of the bulk flux of H2 associated with serpentinization and associated mineralization. Templeton & Ellison [6] emphasize the role of ferroan brucite (Fe,Mg)(OH)2 in hydrogen generation. Brucite is commonly a primary product of serpentinization reactions and this suppresses the potential for formation of magnetite and Fe oxidation. However, ferroan brucite has the potential to reduce water, carbon dioxide and other species in secondary reactions producing hydrogen and Fe(II/III) oxides and hydroxides. Thus, there are a variety of routes to iron oxidation and hydrogen generation that do not directly involve serpentine.Moving onto more specific effects on microbial activity, Lang & Brazelton [7] review the conditions for subsurface life in the subsurface of the LCHF, concluding that the combination of high pH, high T and lack of bioavailable CO2 is very challenging, with implications for the habitability of the subsurface on ocean worlds such as Europa and Enceladus. Boyd et al. [8] resolve a paradox that early anaerobic autotrophic bacteria apparently used ferredoxins (iron–sulfur proteins) as electron donors despite the fact that the reduction potential of H2 is not generally low enough to efficiently reduce ferredoxins. They show that a combination of high H2 concentration and alkaline pH reduce the reduction potential of H2, an indication that serpentinizing systems are favourable for the emergence of autotrophic life.Looking at astrobiology, Vance [9] reviews evidence for the occurrence of serpentine on Mars, Enceladus, Titan and Europa, and details a model for the rate of advance of a cracking front that predicts the extent of serpentinization and associated hydrogen generation over time as these bodies cooled.Finally, Hansen et al. [10] document experiments on nanoindentation of the serpentine polymorph antigorite indicating that deformation at high pressures is dominated by sliding on shear cracks rather than dislocation movement.McClymont, E.L., Ford, H.L., Ho, S.L., Tindall, J.C., Haywood, A.M., Alonso-Garcia, M., Bailey, I., Berke, M.A., Littler, K., Patterson, M., Petrick, B., Peterse, F., Ravelo, A.C., Risebrobakken, B., De Schepper, S., Swann, G.E.A., Thirumalai, K., Tierney, J.E., van der Weijst, C., White, S., 2020. Lessons from a high CO2 world: an ocean view from ~3 million years ago. Climate of the Past Discussions 2020, 1-27. range of future climate scenarios are projected for high atmospheric CO2 concentrations, given uncertainties over future human actions as well as potential environmental and climatic feedbacks. The geological record offers an opportunity to understand climate system response to a range of forcings and feedbacks which operate over multiple temporal and spatial scales. Here, we examine a single interglacial during the late Pliocene (KM5c, ca. 3.205?±?0.01?Ma) when atmospheric CO2 concentrations were higher than pre-industrial, but similar to today and to the lowest emission scenarios for this century. As orbital forcing and continental configurations were almost identical to today, we are able to focus on equilibrium climate system response to modern and near-future CO2. Using proxy data from 32 sites, we demonstrate that global mean sea-surface temperatures were warmer than pre-industrial, by ~?2.3??C for the combined proxy data (foraminifera Mg/Ca and alkenones), or by ~?3.2??C (alkenones only). Compared to the pre-industrial, reduced meridional gradients and enhanced warming in the North Atlantic are consistently reconstructed. There is broad agreement between data and models at the global scale, with regional differences reflecting ocean circulation and/or proxy signals. An uneven distribution of proxy data in time and space does, however, add uncertainty to our anomaly calculations. The reconstructed global mean sea-surface temperature anomaly for KM5c is warmer than all but three of the PlioMIP2 model outputs, and the reconstructed North Atlantic data tend to align with the warmest KM5c model values. Our results demonstrate that even under low CO2 emission scenarios, surface ocean warming may be expected to exceed model projections, and will be accentuated in the higher latitudes.McCollom, T.M., Klein, F., Solheid, P., Moskowitz, B., 2020. The effect of pH on rates of reaction and hydrogen generation during serpentinization. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20180428. series of three laboratory experiments were conducted to investigate how pH affects reaction pathways and rates during serpentinization. Two experiments were conducted under strongly alkaline conditions using olivine as reactant at 200 and 230°C, and the results were compared with previous studies performed using the same reactants and methods at more neutral pH. For both experiments, higher pH resulted in more rapid serpentinization of the olivine and generation of larger amounts of H2 for comparable reaction times. Proportionally greater amounts of Fe were partitioned into brucite and chrysotile and less into magnetite in the experiments conducted at higher pH. In a third experiment, alkaline fluids were injected into an ongoing experiment containing olivine and orthopyroxene to raise the pH from circumneutral to strongly alkaline conditions. Increasing the pH of the olivine-orthopyroxene experiment resulted in an immediate and steep increase in H2 production, and led to far more extensive reaction of the primary minerals compared to a similar experiment conducted under more neutral conditions. The results suggest that the development of strongly alkaline conditions in actively serpentinizing systems promotes increased rates of reaction and H2 production, enhancing the flux of H2 available to support biological activity in these environments.McMahon, S., 2019. Earth's earliest and deepest purported fossils may be iron-mineralized chemical gardens. Proceedings of the Royal Society B: Biological Sciences 286, 20192410. fossil microorganisms is essential to the study of life's origin and evolution and to the ongoing search for life on Mars. Purported fossil microbes in ancient rocks include common assemblages of iron-mineral filaments and tubes. Recently, such assemblages have been interpreted to represent Earth's oldest body fossils, Earth's oldest fossil fungi, and Earth's best analogues for fossils that might form in the basaltic Martian subsurface. Many of these putative fossils exhibit hollow circular cross-sections, lifelike (non-crystallographic, constant-thickness, and bifurcate) branching, anastomosis, nestedness within ‘sheaths’, and other features interpreted as strong evidence for a biological origin, since no abiotic process consistent with the composition of the filaments has been shown to produce these specific lifelike features either in nature or in the laboratory. Here, I show experimentally that abiotic chemical gardening can mimic such purported fossils in both morphology and composition. In particular, chemical gardens meet morphological criteria previously proposed to establish biogenicity, while also producing the precursors to the iron minerals most commonly constitutive of filaments in the rock record. Chemical gardening is likely to occur in nature. Such microstructures should therefore not be assumed to represent fossil microbes without independent corroborating evidence.Mello, F.d.S., Fria?a, A.C.S., 2020. The end of life on Earth is not the end of the world: converging to an estimate of life span of the biosphere? International Journal of Astrobiology 19, 25-42. conditions have changed in the past of our planet but were not hostile enough to extinguish life. In the future, an aged Earth and a more luminous Sun may lead to harsh or even uninhabitable conditions for life. In order to estimate the life span of the biosphere we built a minimal model of the co-evolution of the geosphere, atmosphere and biosphere of our planet, taking into account temperature boundaries, CO2 partial pressure lower limits for C3 and C4 plants, and the presence of enough surface water. Our results indicate that the end of the biosphere will happen long before the Sun becomes a red giant, as the biosphere faces increasingly more difficult conditions in the future until its collapse due to high temperatures. The lower limit for CO2 partial pressure for C3 plants will be reached in 170(+ 320, ? 110) Myr, followed by the C4 plants limit in 840(+ 270, ? 100) Myr. The mean surface temperature will reach 373 K in 1.63(+ 0.14, ? 0.05) Gyr, a point that would mark the extinction of the biosphere. Water loss due to internal geophysical processes will not be dramatic, implying almost no variation in the surface ocean mass and ocean depth for the next 1.5 billion years. Our predictions show qualitative convergence and some quantitative agreement with results found in the literature, but there is considerable scattering in the scale of hundreds of millions of years for all the criteria devised. Even considering these uncertainties, the end of the biosphere will hardly happen sooner than 1.5 Gyr.Melnikov, A.D., Tsentalovich, Y.P., Yanshole, V.V., 2020. Deep learning for the precise peak detection in high-resolution LC–MS data. Analytical Chemistry 92, 588-592. letter is devoted to the application of machine learning, namely, convolutional neural networks to solve problems in the initial steps of the common pipeline for data analysis in metabolomics. These steps are the peak detection and the peak integration in raw liquid chromatography–mass spectrometry (LC–MS) data. Widely used algorithms suffer from rather poor precision for these tasks, yielding many false positive signals. In the present work, we developed an algorithm named peakonly, which has high flexibility for the detection or exclusion of low-intensity noisy peaks, and shows excellent quality in the detection of true positive peaks, approaching the highest possible precision. The current approach was developed for the analysis of high-resolution LC–MS data for the purposes of metabolomics, but potentially it can be applied with several adaptations in other fields, which utilize high-resolution GC? or LC–MS techniques. Peakonly is freely available on GitHub () under an MIT license.Melosh, H.J., 2020. The Australasian tektite source crater: Found at last? Proceedings of the National Academy of Sciences 117, 1252. on: Sieh, K., Herrin, J., Jicha, B., Schonwalder Angel, D., Moore, J.D.P., Banerjee, P., Wiwegwin, W., Sihavong, V., Singer, B., Chualaowanich, T., Charusiri, P., 2020. Australasian impact crater buried under the Bolaven volcanic field, Southern Laos. Proceedings of the National Academy of Sciences 117, 1346.In PNAS, Sieh et al. (1) present the best candidate yet for the long-sought source crater of the Australasian tektite strewn field. Unlike the other 4 or so tektite strewn fields, each of which can be traced back to a large impact crater, the Australasian field’s source has yet to be definitively located. While this proposal does not fully prove the case, it offers strong evidence implicating a ～15-km-diameter impact crater in Laos that has been hiding in plain sight beneath a mass of younger volcanic rocks. From here, it is clear that the next step in proving its parentage must be drilling through the volcanic rocks into the putative impact rocks below.Tektites are centimeter-scale black or green blobs of glass that have long fascinated humans (2). Moldavites, an Eastern European variety, were found interred with the much more famous Venus of Willendorf, dating back to 30,000 BCE, possibly reflecting our ancestors’ interest in unusual rocks as well as female deities. Individual tektites occur in widely strewn fields of which about 4 are currently known (there are other candidate strewn fields). Each of these fields, which extend over hundreds to thousands of kilometers, is associated with a meteorite impact crater—except one, the biggest of them all, the Australasian strewn field. It ranges south from Southeast Asia, across Australia then south of Tasmania to East Antarctica, with a western extension that crosses over Madagascar and an eastern extension into the western Pacific Ocean, covering about 10% of Earth’s surface. The tektites in this enormous field have been intensively studied using modern analytical methods. They are divided into a number of distinct types, ranging from meter-scale irregular masses of black glass called Muong Nong …Mijnendonckx, K., Van Gompel, A., Coninx, I., Bleyen, N., Leys, N., 2020. Water-soluble bitumen degradation products can fuel nitrate reduction from non-radioactive bituminized waste. Applied Geochemistry 114, 104525. important fraction of the currently stored volume of long-lived intermediate level radioactive waste in Belgium is immobilized as Eurobitum. This type of waste typically contains large amounts of NaNO3 homogeneously dispersed in a hard bituminous matrix. Geological disposal of Eurobitum in a water-saturated sedimentary formation such as Boom Clay will result in the leaching of high concentrations of NaNO3 in the Boom Clay formation. This could cause a geochemical perturbation of the surrounding clay, possibly affecting some of the favorable characteristics of the host formation such as its hydraulic conductivity, sorption potential or the redox conditions. The latter might result in a decrease of its reducing capacity and an increase in the mobility of redox-sensitive radionuclides. Microbial nitrate reduction is a well-known process, which could be stimulated by the chemical and radiolytical water-soluble organic bitumen degradation products. The present study carried out different series of long-term anoxic batch experiments to investigate the ability of the microbial community of Boom Clay borehole water to reduce nitrate, leaching from thermally aged non-radioactive Eurobitum in the presence or absence of acetate, formate and oxalate, being part of the most important organic bitumen degradation products. Obtained results indicate that all three organic bitumen degradation products can be used as electron donor to fuel microbial nitrate reduction, albeit with a different efficiency. The highest nitrate reduction rate was observed in the presence of acetate, while oxalate was the least efficient electron donor for nitrate reduction. Moreover, organic compounds that leached from the Eurobitum during the course of the experiment were used as electron donor for microbial nitrate reduction in all conditions. Furthermore, calcium oxalate crystals were observed, indicating that if oxalate is present, it will probably be less bioavailable compared to other organic compounds.Miranda, M.L., Osterholz, H., Giebel, H.A., Bruhnke, P., Dittmar, T., Zielinski, O., 2020. Impact of UV radiation on DOM transformation on molecular level using FT-ICR-MS and PARAFAC. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 230, 118027. organic matter (DOM) is an omnipresent constituent of natural water bodies. Reuse and transformation of DOM compounds in the water column is driven by physicochemical and biological processes leading to the production of refractory DOM. Typically, breakdown of DOM chemical compounds into smaller or more condensed fragments is triggered by ultraviolet (UV) radiation. Here, we present a study on the photodegradation of DOM produced during an incubation experiment with a natural microbial community. At the end of the first incubation without UV irradiation, the samples from 3 mesocosms were filtered to remove microbes and particles and continuously exposed to UV radiation (280–365?nm). We investigated DOM in depth via monitoring of dissolved organic carbon (DOC) concentrations, DOM molecular characterization by Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS) and excitation emission matrix spectroscopy (EEMS). Analysis of variance indicated no significant differences in the DOC concentration between treatments. Main peaks in the fluorescent DOM (FDOM) were photo-bleached by UV radiation, and an increase in the fluorescent intensity of selected peaks was observed on irradiated samples toward the end of the experiment. Parallel factor analysis (PARAFAC) indicated the presence of three main components in all treatments: C1 (Marine humic M), C2 (Bacterial produced humic C), C3 (Tyrosine), and an additional component in the dark incubation of mesocosm 3, C4 (Tryptophan). Despite an intensive filtration protocol through 0.7, 0.2 and 0.1?μm filters, low bacterial abundances were determined (<2.5?×?10?3 cells mL?1). We observed a direct correlation between structural indices and the intensity of PARAFAC components. Average double bond equivalent and aromaticity were strongly positively correlated with PARAFAC components C1 and C2 for one or more mesocosm. Moreover, FT-ICR-MS showed that under the tested conditions, the recalcitrance of the DOM assessed as the similarity to a deep ocean DOM reference did not increase on molecular level. Thus, mechanisms other than photochemical transformations of relatively recent DOM are likely necessary to facilitate long-term stability of DOM in the oceans.Miyajima, Y., Watanabe, Y., Goto, A.S., Jenkins, R.G., Sakai, S., Matsumoto, R., Hasegawa, T., 2020. Archaeal lipid biomarker as a tool to constrain the origin of methane at ancient methane seeps: Insight into subsurface fluid flow in the geological past. Journal of Asian Earth Sciences 189, 104134. origin of methane discharged at ancient methane seeps is a key to understand subsurface fluid-flow processes in sedimentary basins. The carbon isotopic composition of methane-seep carbonates can be used to estimate the origin of methane, but mixing of multiple carbon sources results in ambiguous interpretation. We here constrained the origin of methane at ancient seeps by using the carbon isotopic composition and the isotope fractionation of lipid biomarkers of anaerobic methane-oxidizing archaea. We estimated the carbon-isotope fractionation between methane and biomarkers as the offset between their δ13C values at modern seep sites in the Japan Sea and other regions of the world. The biomarker pentamethylicosane (PMI) extracted from a modern seep carbonate of the Japan Sea shows a 44‰ offset from the seep methane. On the basis of literature data, we calculated the carbon-isotope offset as mostly ~20–60‰ for PMI at modern seeps across the world. We also assessed the relationship of the δ13C values between methane and biomarkers by regression analysis on the data taken at the modern seeps, obtaining regression formulas to estimate the δ13C values of methane from those of biomarkers. For ancient seeps, we examined Miocene to Pleistocene methane-seep carbonate rocks collected from Japan Sea sediments. PMI extracted from these ancient carbonates have δ13C values ranging from ?137‰ to ?93‰. Using the δ13C values of PMI and the carbon-isotope offset and regression formulas, we estimated that the methane at the ancient seeps was mainly of biogenic origin and migrated from the shallow subsurface.Miyazawa, D., Thanh, L.T.H., Tani, A., Shintani, M., Loc, N.H., Hatta, T., Kimbara, K., 2019. Isolation and characterization of genes responsible for naphthalene degradation from thermophilic naphthalene degrader, Geobacillus sp. JF8. Microorganisms 8, 44. sp. JF8 is a thermophilic biphenyl and naphthalene degrader. To identify the naphthalene degradation genes, cis-naphthalene dihydrodiol dehydrogenase was purified from naphthalene-grown cells, and its N-terminal amino acid sequence was determined. Using a DNA probe encoding the N-terminal region of the dehydrogenase, a 10-kb DNA fragment was isolated. Upstream of nahB, a gene for dehydrogenase, there were two open reading frames which were designated as nahAc and nahAd, respectively. The products of nahAc and nahAd were predicted to be alpha and beta subunit of ring-hydroxylating dioxygenases, respectively. Phylogenetic analysis of amino acid sequences of NahB indicated that it did not belong to the cis-dihydrodiol dehydrogenase group that includes those of classical naphthalene degradation pathways. Downstream of nahB, four open reading frames were found, and their products were predicted as meta-cleavage product hydrolase, monooxygenase, dehydrogenase, and gentisate 1,2-dioxygenase, respectively. A reverse transcriptase-PCR analysis showed that transcription of nahAcAd was induced by naphthalene. These findings indicate that we successfully identified genes involved in the upper pathway of naphthalene degradation from a thermophilic bacterium.Mohammad, S., Fariba, F., Ebrahim, G.-N., Ali, S., Mohsen, Y.-M., Mehdi, S., 2019. Integrated biostratigraphy, depositional setting and geochemical analyses for petroleum potential evaluation of the Lower Cretaceous (Barremian – Albian) Strata of the Koppeh-Dagh Basin, northeastern Iran. Acta Geologica Sinica - English Edition 93, 1885-1899.‐formed gas generated from the Permo‐Carboniferous coal measures has become one of the most important targets for deep hydrocarbon exploration in the Bohai Bay Basin, offshore eastern China. However, the proven gas reserves from this source rock remain low to date, and the distribution characteristics and accumulation model for the coal‐formed gas are not clear. Here we review the coal‐formed gas deposits formed from the Permo‐Carboniferous coal measures in the Bohai Bay Basin. The accumulations are scattered, and dominated by middle‐small sized gas fields, of which the proven reserves ranging from 0.002 to 149.4×108 m3 with an average of 44.30×108 m3 and a mid‐point of 8.16×108 m3. The commercially valuable gas fields are mainly found in the central and southern parts of the basin. Vertically, the coal‐formed gas is accumulated at multiple stratigraphic levels from Paleogene to Archaeozoic, among which the Paleogene and Permo‐Carboniferous are the main reservoir strata. According to the transporting pathway, filling mechanism and the relationship between source rocks and reservoir, the coal‐formed gas accumulation model can be defined into three types: “Upward migrated, fault transported gas” accumulation model, “Laterally migrated, sandbody transported gas” accumulation model, and “Downward migrated, sub‐source, fracture transported gas” accumulation model. Source rock distribution, thermal evolution and hydrocarbon generation capacity are the fundamental controlling factors for the macro distribution and enrichment of the coal‐formed gas. The fault activity and the configuration of fault and caprock control the vertical enrichment pattern.Montas, L., Ferguson, A.C., Mena, K.D., Solo-Gabriele, H.M., 2020. Categorization of nearshore sampling data using oil slick trajectory predictions. Marine Pollution Bulletin 150, 110577. Spill Chemicals (OSCs) represent a risk to the environment and human health, especially in nearshore environments used for recreational purposes. Importantly, the starting point for human health risk assessment is to define the concentration of OSCs at nearshore locations. The objective of this study was to evaluate nearshore sampling data of OSC concentrations in different environmental matrices within time-space specific categories. The categories correspond to OSC concentration values for samples collected prior to nearshore oiling, post nearshore oiling and at no time impacted by oil as predicted by historic oil spill trajectories generated by an Oil Spill Trajectory Model. In general, concentration values for the post category were higher than prior which were higher than unimpacted. Results show differences in PAH concentration patterns within each matrix and for each category. Concentration frequency distributions for most chemicals in each category were log-normally distributed.Moore, J., Rose, A., Anderson, S., Evans, J., Nowell, G., Gr?cke, D.R., Pashley, V., Kirby, M., Montgomery, J., 2020. A multi-isotope (C, N, O, Sr, Pb) study of Iron Age and Roman period skeletons from east Edinburgh, Scotland exploring the relationship between decapitation burials and geographical origins. Journal of Archaeological Science: Reports 29, 102075. excavations at Musselburgh, East Lothian (Scotland) revealed twelve skeletons, radiocarbon dated to the Iron Age and Roman period. The high incidence of skeletal trauma characteristic of decapitation in those of Roman date makes this site unusual. A multi-isotope investigation of seven of these individuals was conducted to explore any link between intrusive burial practices and migration at one of Britain’s most northerly frontiers. Bulk collagen analysis provided a terrestrial, C3, dietary protein signal (mean δ13C ?20.4‰ and δ15N + 11.1‰), consistent with other Romano-British studies. However, the range of δ18O, 87Sr/86Sr and Pb isotopes indicate more diverse origins for the Roman individuals. These results suggest that decapitation burials were afforded to migrants to the Lothian area, but is not indicative of a common origin, implying that something more complex than a shared geographic childhood origin united these individuals. The possible association of these decapitation burials with a nearby 2nd century fort suggests that they may also represent some of the earliest examples of Roman decapitation burials to be found anywhere in Britain.Morgan, V.G., Bastos, T.M., Sad, C.M.S., Leite, J.S.D., Castro, E.R.V., Barbosa, L.L., 2020. Application of low-field nuclear magnetic resonance to assess the onset of asphaltene precipitation in petroleum. Fuel 265, 116955. of the onset of the asphaltene precipitation point is important in preventing pipe clogging and the reduction of productivity. In this study, we propose a new and simple strategy to determine the onset point of asphaltene precipitation by a low-field nuclear magnetic resonance (NMR) technique based on transverse relaxation time (T2) measurements. Six Brazilian crude oil (light, medium, and heavy) samples, with asphaltene contents ranging from 0.10 to 7.10 wt%, were assessed using n-heptane as the precipitant, according to the ASTM D6560 method. The good correlation between T2 and the n-heptane/oil ratio indicated the onset precipitation values between 0.931 and 2.759 mL g?1. NMR results shows agreement with optical microscopy and literature results. We also propose a correlation between asphaltene content and onset of the asphaltene precipitation. This new idea expand the applicability of low-field NMR in crude oil studies, providing an alternative method for asphaltene precipitation under laboratory conditions and opens the possibility to quantifying the asphaltene content in crude oil without the laborious standard ASTM method.Moro, M.K., Neto, ?.C., Lacerda, V., Rom?o, W., Chinelatto, L.S., Castro, E.V.R., Filgueiras, P.R., 2020. FTIR, 1H and 13C NMR data fusion to predict crude oils properties. Fuel 263, 116721. fusion from different analytical sources can be a feasible way to estimate physicochemical properties of petroleum when compared to using a single analytical technique. This occurs because outputs of different instrumental techniques can carry complementary information and act synergistically during calibration. In this paper, we investigate the potential of data fusion strategies for estimating seven crude oil properties: sulphur content (S), total nitrogen content (TN), basic nitrogen content (BN), total acid number (TAN), saturated (SAT), aromatic (ARO) and polar (POL) contents. We used 127 crude oil samples split into 70% for calibration and 30% for prediction. Partial least squares (PLS) regression models were constructed from Fourier transform mid-infrared (FTIR) and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. Data fusion models were built: fused at low and mid-level in different combinations. While mid-level fusion usually increased the accuracy of models, low-level fusion caused insignificant improvements. Using PLS mid-level fusion, we estimated S, TN, BN, TAN, SAT, ARO and POL contents with average prediction errors of 0.064 wt%, 0.049 wt%, 0.0070 wt%, 0.16 mgKOH·g?1, 5.34 wt%, 3.66 wt% and 6.58 wt%, respectively, with coefficients of determination equal to 0.87, 0.78, 0.98, 0.91, 0.79, 0.67 and 0.63 for the prediction set and using 4, 3, 3, 3, 2, 4 and 2 latent variables, respectively. Although promising results were obtained, mid-level fusion demonstrates to be the best strategy usually improving accuracy of models.Mota, A.C.S., Santos, J.M., Pereira, M.S., Ataíde, C.H., 2020. Microwave drying of olefins from drill cuttings and analysis of the organic phase recovered during drying operation. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 75, 1. main objective of the present work was to study the influence of different operating conditions in the microwave drying of drill cuttings and an eventual degradation of the condensed liquid collected during this operation. For this, a Central Composite Design (CCD) was used, considering three independent variables at three levels: initial olefin content (7.5, 10, and 12.5% w/w), power (250, 500, and 750 W), and time (5, 10, and 15 min); the residual olefin content being the response analyzed in the conducted tests without monitoring or control of the cutting’s temperature. All three variables studied were statistically significant, presenting a positive or negative effect on residual olefin content. As expected, the initial olefin content had a negative effect on the response. On the other hand, when considering the applied power and the drying time, the effect on decontamination yield was positive. The results showed that cuttings can be decontaminated at lower levels than those required by environmental legislation (offshore drilling), reaching residual olefin mass contents of less than 1%. Finally, the organic phase of recovered liquids, after the condensation of vapors produced during drying, was analyzed by gas chromatography technique. It was observed greater olefin degradation in the longer and higher power tests, especially in samples of condensed liquid collected inside the microwave oven.Mukhopadhyay, J., 2020. Archean banded iron formations of India. Earth-Science Reviews 201, 102927. banded iron formations (BIFs) are important lithologies for understanding the early Earth processes. Greenstone belts in the four Archean cratonic nucleii of peninsular India, namely, Singhbhum, Bastar, Dharwar, and Bundelkhand host BIF units that can be important candidates for case studies. The BIFs in these greenstone successions represent both Algoma- and Superior-type associations. The oldest record comes from the Paleoarchean Southern, Eastern and Western Iron Group of the Singhbhum craton and the Sargur supracrustals of the Dharwar craton. Mesoarchean and Neoarchean greenstone belts in the Dharwar and Bundelkhand cratons record a number of cycles of BIF deposition in a spectrum of depositional settings from manganiferous arenite-carbonate shelf associations to deep-water volcanics and graywacke associations. The BIFs from the Neoarchean Bailadila Group in the Bastar craton were deposited in siliciclastic shelf association. Compositional variations in major, trace and REE patterns have been evaluated from published data. High-grade iron ores are mainly mined from the BIFs and locally Mn-ores occur in association as well. Microbial carbonates associated with some of the Paleoarchean as well as Neoarchean iron-manganese formations suggest early life activities. The lithological association of the Archean iron formations have been explained in terms of both active margin and passive margin depositional settings. BIFs in association with manganiferous formations as old as Paleoarchean time provide an opportunity to probe into the redox stratification of oceanic hydrosphere and in turn the oxygenation of early atmosphere.Müller, H., Marozava, S., Probst, A.J., Meckenstock, R.U., 2020. Groundwater cable bacteria conserve energy by sulfur disproportionation. The ISME Journal 14, 623-634. bacteria of the family Desulfobulbaceae couple spatially separated sulfur oxidation and oxygen or nitrate reduction by long-distance electron transfer, which can constitute the dominant sulfur oxidation process in shallow sediments. However, it remains unknown how cells in the anoxic part of the centimeter-long filaments conserve energy. We found 16S rRNA gene sequences similar to groundwater cable bacteria in a 1-methylnaphthalene-degrading culture (1MN). Cultivation with elemental sulfur and thiosulfate with ferrihydrite or nitrate as electron acceptors resulted in a first cable bacteria enrichment culture dominated >90% by 16S rRNA sequences belonging to the Desulfobulbaceae. Desulfobulbaceae-specific fluorescence in situ hybridization (FISH) unveiled single cells and filaments of up to several hundred micrometers length to belong to the same species. The Desulfobulbaceae filaments also showed the distinctive cable bacteria morphology with their continuous ridge pattern as revealed by atomic force microscopy. The cable bacteria grew with nitrate as electron acceptor and elemental sulfur and thiosulfate as electron donor, but also by sulfur disproportionation when Fe(Cl)2 or Fe(OH)3 were present as sulfide scavengers. Metabolic reconstruction based on the first nearly complete genome of groundwater cable bacteria revealed the potential for sulfur disproportionation and a chemo-litho-autotrophic metabolism. The presence of different types of hydrogenases in the genome suggests that they can utilize hydrogen as alternative electron donor. Our results imply that cable bacteria not only use sulfide oxidation coupled to oxygen or nitrate reduction by LDET for energy conservation, but sulfur disproportionation might constitute the energy metabolism for cells in large parts of the cable bacterial filaments.Nelson, J.P., 2020. Mythic forecasts: researcher portrayals of extraterrestrial life discovery. International Journal of Astrobiology 19, 16-24. discovery, especially at the boundaries of human observational capacity, is an extended, incremental and sometimes controversy-laden process; but practicing researchers' published statements do not always portray it as such. If extraterrestrial life (ETL) exists, and if we find it, the process of observation, interpretation, understanding and confirmation may take decades. Though it is, thus, likely that scientific consensus will accrue around an ETL interpretation in a gradual and subtle process, the general public and even practicing scientists often discuss ETL discovery as though it will be rapid and dramatic. To illustrate this phenomenon, this review analyses a convenience sample of astronomers', astrobiologists' and astrosociologists' statements and assumptions in scholarly and general-audience media regarding a prospective discovery of ETL. Of 30 surveyed scholarly studies and 37 surveyed general-audience pieces, 24 scholarly and scientists' perspectives in 32 general-audience pieces do not acknowledge the extended nature of scientific discovery; and only three and four, respectively, do so explicitly. These results suggest that ETL researchers' statements could often portray an inaccurate or at least atypical vision of scientific progress in their own studies and to general-audience media outlets.Neupane, B., Zhao, J., Ju, Y., Baral, U., 2020. Occurrence of unconventional hydrocarbon deposits and its structural relation in Nepal Himalaya: implication for future exploration. Arabian Journal of Geosciences 13, 81. to tectonic movement, compressed structures, and mountain upliftment process, several sedimentary basins have evolved in the periphery of the Himalayan orogeny. The evolution of sedimentary basins within the Central Himalaya (i.e., Nepal Himalaya) is quite similar in age (i.e., Eocene–Recent). The sedimentary sequences within this basin are marked by large-scale geological structures (e.g., Main Central Thrust, Main Boundary Thrust, and Main Frontal Thrust). The Lesser Himalayan (Eocene-Miocene) foreland basin in far western Nepal contains various hydrocarbon deposits. Similarly, the shallow marine shale, coal seams numerous fossils, and tight sand layers are the important sources of energy resources. The sedimentary basin, Surkhet Group in the western Nepal, is the prospective area for the unconventional hydrocarbon deposit. Due to active geological structures (such as Ranimatta Thrust, Budar Thrust, Mahabharat Thrust, and Nabi Khola Anticline), oil and gas seem to have migrated upward in the Padukasthan, Nabhisthan, and Sristhan. Therefore, the active oil and gas seepage occur locally in this area. Due to lack of scientific engineering research, the utilization of various energy resources of Central Himalaya (Nepal Himalaya) is important but challenging. There is not much work carried out on this section; the present study discussed about the relationship between the sedimentary structures and the formation of unconventional gas and its prospects in the Nepal Himalaya region.Ngueleu, S.K., Al-Raoush, R.I., Shafieiyoun, S., Rezanezhad, F., Van Cappellen, P., 2019. Biodegradation kinetics of benzene and naphthalene in the vadose and saturated zones of a (semi)-arid saline coastal soil environment. Geofluids 2019, 8124716. is a key process for the remediation of sites contaminated by petroleum hydrocarbons (PHCs), but this process is not well known for the (semi)-arid coastal environments where saline conditions and continuous water level fluctuations are common. This study differs from the limited previous studies on the biodegradation of PHCs in Qatari coastal soils mainly by its findings on the biodegradation kinetics of the selected PHCs of benzene and naphthalene by indigenous bacteria. Soil samples were collected above, across, and below the groundwater table at the eastern coast of Qatar within a depth of 0 to -40?cm. Environmental conditions combining low oxygen and high sulfate concentrations were considered in this study which could favor either or both aerobic and anaerobic bacteria including sulfate-reducing bacteria (SRB). The consideration of SRB was motivated by previously reported high sulfate concentrations in Qatari soil and groundwater. Low- and high-salinity conditions were applied in the experiments, and the results showed the sorption of the two PHCs on the soil samples. Sorption was dominant for naphthalene whereas the biodegradation process contributed the most for the removal of benzene from water. Losses of nitrate observed in the biodegradation experiments were attributed to the activity of nitrate-reducing bacteria (NRB). The results suggested that aerobic, NRB, and most likely SRB biodegraded the two PHCs, where the combined contribution of sorption and biodegradation in biotic microcosms led to considerable concentration losses of the two PHCs in the aqueous phase (31 to 58% after 21 to 35 days). Although benzene was degraded faster than naphthalene, the biodegradation of these two PHCs was in general very slow with rate coefficients in the order of 10-3 to 10-2 day-1 and the applied kinetic models fitted the experimental results very well. It is relevant to mention that these rate coefficients are the contribution from all the microbial groups in the soil and not from just one.Nguyen, T.B., Top?uo?lu, B.D., Holden, J.F., LaRowe, D.E., Lang, S.Q., 2020. Lower hydrogen flux leads to larger carbon isotopic fractionation of methane and biomarkers during hydrogenotrophic methanogenesis. Geochimica et Cosmochimica Acta 271, 212-226. isotopic composition of lipid biomarkers and biomass in sedimentary environments are widely used to infer microbial metabolisms and constrain carbon cycling processes. It has been observed that metabolic energy availability in the form of H2 impacts the stable carbon isotopes of CH4 during hydrogenotrophic methanogenesis, but it is unknown whether this relationship extends to lipids and amino acids. Since lipids and amino acids are long-lived, they can be used to reconstruct past conditions over geologic timescales. Therefore, the controls on their isotopic signatures are important to constrain to better interpret past environments.In this study, the isotopic distributions of carbon metabolized and reduced by the hyperthermophile Methanocaldococcus jannaschii were quantified following growth at 82?°C in a chemostat with high (80–83??M) and low (15–27??M) H2 concentrations. As has been shown previously, the stable carbon isotope fractionation factors for CH4 were >15‰ larger in low H2 experiments than in high H2 experiments. Lipid biomarkers and amino acids were similarly impacted with approximately 10‰ larger fractionation factors under low H2 conditions. The increase in fractionation factors can be related to the lower availability of thermodynamic energy, suggesting that even larger fractionation factors would be observed in methanogens living close to their threshold energy needs, as they do in most environments. The resulting isotopic signatures of long-lived lipid biomarkers synthesized by hydrogenotrophic methanogens may become as ‘superlight’ as those synthesized by archaea carrying out the anaerobic oxidation of methane. These results help to describe the underlying mechanisms that determine the isotopic composition of long-lived biomarkers and provide constraints for interpreting these signatures in the environment.Ni, M., Li, S., 2020. Optical properties as tracers of riverine dissolved organic matter biodegradation in a headwater tributary of the Yangtze. Journal of Hydrology 582, 124497. optical properties can characterize the chemical composition, bioavailability and origins of dissolved organic matter (DOM), and thus indicate its biodegradability in natural waters. However, there remains a large gap in how DOM optical properties (UV-visible and fluorescence spectra) trace and predict the dissolved organic carbon biodegradation (%BDOC) in river systems. Over a 56-day laboratory incubation experiment, we examined the variations of %BDOC and DOM optical properties in a headwater tributary of the upper Yangtze River. We found that DOC biodegradability was significantly higher in the tributaries (20°C: 38.9 ± 19.8%; 30°C: 58.6 ± 19.5%) than that in the main stem (20°C: 26.1 ± 18.2%: 30°C: 41.8 ± 16.3%) (p < 0.001). The %BDOC, exhibiting coincident peaks in the agricultural regions and troughs in the ecologically fragile regions, increased by a factor of two-fold with a temperature gradient of 10℃. The optical properties SUVA254 and S275-295 decreased, while the S350-400, FI and BIX increased after the incubations, implying the synchronous biodegradation and production of young DOMs via microbial respiration. The %BDOC:DOC tightly linked to a254, S275-295, S350-400 and BIX, illustrating that optical properties could predict the riverine %BDOC. The findings demonstrated that optical properties could be regarded as the useful tracers of DOM biodegradation in river systems.Ni, Z., Chen, Z., Li, M., Yang, C., Wen, L., Hong, H., Luo, B., 2020. Trace element characterization of bitumen constraints on the hydrocarbon source of the giant gas field in Sichuan Basin, South China. Geological Journal 55, 317-329. exploration of high production, natural gas wells (>106 m3/d) has been extremely successful in the Gaoshiti and Moxi areas of the Leshan–Longnvsi paleo‐uplift, in the west‐central Sichuan Basin. This paper focuses on the Sinian and Cambrian reservoirs from the Gaoshiti and Moxi areas, where a dataset of new trace elements in bitumen and potential source rock is reported and where hydrocarbon‐source correlation is attempted based on trace elements characteristics of the 12 potential source rocks and 22 bitumen samples. Results show that the bitumen from the three reservoirs can be distinguished from each other using trace element distribution patterns and redox‐ and provenance‐sensitive elemental ratios. Bitumen in the second and fourth members of the Sinian Dengying Formation were derived primarily from the third member of the source rocks of the Dengying Formation, which represents a self‐sourced paleo‐petroleum system. In contrast, bitumen in the reservoirs of the Cambrian Longwangmiao Formation is derived from the Cambrian Qiongzhusi Formation and third member of Dengying Formation. The trace element method used in this study improves our understanding of the complex hydrocarbon–source relation and confirm the potential target for petroleum exploration in the study area.Nielsen, S.D., Koren, K., L?bmann, K., Hinge, M., Scoma, A., Kjeldsen, K.U., R?y, H., 2020. Constraints on CaCO3 precipitation in superabsorbent polymer by aerobic bacteria. Applied Microbiology and Biotechnology 104, 365-375. induced CaCO3 precipitation (MICP) can give concrete self-healing properties. MICP agents are typically bacterial endospores which are coated into shelled granules, infused into expanded clay, or embedded into superabsorbent polymer (SAP). When small cracks appear in the cured concrete, the encapsulation is broken and the metabolic CO2 production from the germinated bacteria causes healing of the cracks by precipitation of CaCO3. Such systems are being tested empirically at large scales, but survival of endospores through preparation and application, as well as germination and growth kinetics of the germinated vegetative cells, remains poorly resolved. We encapsulated endospores of Bacillus subtilis and Bacillus alkalinitrilicus in crosslinked acrylamide-based SAP and quantified their germination, growth, and, in the case of B. alkalinitrilicus, CaCO3 precipitation potential. The endospores survived crosslinking and desiccation inside the polymer matrix. Microcalorimetry and microscopy showed that ~?80% of the encapsulated endospores of both strains readily germinated after rehydration of freeze-dried SAP. Germinated cells grew into dense colonies of cells inside the SAP, and those of B. alkalinitrilicus calcified with up to 0.3 g CaCO3 produced per g desiccated SAP when incubated aerobically. Measurements by planar optodes indicated that the precipitation rates were inherently oxygen limited due to diffusional constraints, rather than limited by electron donor or Ca2+ availability. Such oxygen limitation will limit MICP in all water-saturated and oxygen-dependent systems, and MICP agents based on anaerobic bacteria, e.g., nitrate reducers, should be developed to broaden the applicability of bioactive self-healing concretes to wet and waterlogged environments.Nikolova, C., Gutierrez, T., 2020. Use of microorganisms in the recovery of oil from recalcitrant oil reservoirs: Current state of knowledge, technological advances and future perspectives. Frontiers in Microbiology 10, 2996. doi: 10.3389/fmicb.2019. 02996. depletion of oil resources, increasing global energy demand, the current low, yet unpredictable, price of oil, and increasing maturity of major oil fields has driven the need for the development of oil recovery technologies that are less costly and, where possible, environmentally compatible. Using current technologies, between 20 and 40% of the original oil in a reservoir can be extracted by conventional production operations (e.g., vertical drilling), with secondary recovery methods yielding a further 15–25%. Hence, up to 55% of the original oil can remain unrecovered in a reservoir. Enhanced oil recovery (EOR) is a tertiary recovery process that involves application of different thermal, chemical, and microbial processes to recover an additional 7–15% of the original oil in place (OOIP) at an economically feasible production rate from poor-performing and depleted oil wells. EOR can significantly impact oil production, as increase in the recovery rate of oil by even a small margin could bring significant revenues without developing unconventional resources. Microbial enhanced oil recovery (MEOR) is an attractive, alternative oil recovery approach, which is claimed to potentially recover up to 50% of residual oil. The in situ production of biological surface-active compounds (e.g., biosurfactants) during the MEOR process does not require vast energy inputs and are not affected by global crude oil prices. Compared to other EOR methods, MEOR can be an economically and more environmentally friendly alternative. In this review, the current state of knowledge of MEOR, with insights from discussions with the industry and other stakeholders, is presented and in addition to the future outlook for this technology.Nomchong, B.J., Van Kranendonk, M.J., 2020. Diverse thrombolites from the c. 2.4?Ga Turee Creek Group, Western Australia. Precambrian Research 338, 105593. from a stromatolite-thrombolite reef complex of the c. 2.4?Ga Turee Creek Group, Western Australia, indicate diversity in stromatolite and microfossil morphology, in addition to the appearance of clotted (thrombolite-like) microbialites (Barlow et al., 2016, Barlow and Van Kranendonk, 2018). Here, we document the diverse morphologies and textures of clotted microbialites from the Turee Creek Group reef complex that occur interbedded and interlayered with stromatolites and sediments in the supratidal to subtidal facies. The clotted microbialites consist of four types with distinct gross morphology, mesostructure, and microtextures, including: 1) an aggregate of isolated, millimetre-scale organic-rich clots that accumulated following storm events and were cemented by coarsely crystalline radiating carbonate; 2) domal bioherms composed of a framework of non-laminated branching columns; 3) stratiform clotted microbialites consisting of fine-grained clots that form both an interconnected framework surrounded by coarsely crystalline cement, or comprise a poorly-defined mixture of fine- and coarsely crystalline textural components; and 4) thrombolites that comprise lobate bioherms with non-layered internal textures. Variations in thrombolite texture and morphology are likely driven by a combination of environmental and biological factors, as is the case in modern microbial carbonate environments, such as Shark Bay and the Bahamas. These findings show that the Turee Creek Group clotted microbialites are significantly more diverse than first recognised, adding to previously documented expressions of microbialite complexity from this microbialite reef complex.Norouzi, N., Fani, M., Ziarani, Z.K., 2020. The fall of oil Age: A scenario planning approach over the last peak oil of human history by 2040. Journal of Petroleum Science and Engineering 188, 106827. the late 50s a debate on the Oil depletion has been started which is continuing to the present day. Campbell largely updated Hubert's model with new reserve resources forecast and estimated that the world's oil production would peak around the 2004–2006 and then would decline over the years. Then was Campbell who proposed the term which was later widely used as the “The peak Oil” to define the global maximum of the Oil production Time series. In this paper a scenario planning based on the expert-choices (participated by the OPEC experts and policy makers) combined with the Hubert's forecast method (based on the Monte-Carlo non-linear forecast Regression) is done for the peak-oil forecasting and three high score scenarios have been derived. The “True me”, the “feigned sleep” and the death of the unity in which these scenarios are highly affected by the political environments of each. However, in one of the scenarios because of the tensions in the political environment the peak oil will not occur by 2040 but the other scenarios show that peak oil maybe is sooner than the world expects (the mid-2020s) and energy supply and demand markets must be ready for this phenomena.Nunes, V.O., Silva, R.V.S., Romeiro, G.A., Azevedo, D.A., 2020. The speciation of the organic compounds of slow pyrolysis bio-oils from Brazilian tropical seed cake fruits using high-resolution techniques: GC?×?GC-TOFMS and ESI(±)-Orbitrap HRMS. Microchemical Journal 153, 104514. view of increasing energy needs in modern society and the desire to replace current energy sources with clean and sustainable ones, biomass is now considered to be a renewable energy source with considerable potential. As Brazil is a major agricultural producer, the reuse of its agroindustrial residues is being explored to find ways to utilize this waste. In the current study, soursop seed cake (SSC) and bocaiuva seed cake (BSC) were processed using slow pyrolysis to obtain bio-oil. Comprehensive two-dimensional gas chromatography (GC?×?GC) with time-of-flight (TOF) mass spectrometry (MS) (GC?×?GC-TOFMS), and positive ion and negative ion (±) electrospray ionization (ESI), coupled with Orbitrap high-resolution (HR) mass spectrometry (MS) (HRMS) (i.e., ESI(±)-Orbitrap HRMS), was performed to provide complementary and comprehensive characterization of the bio-oils, without pre-treatment. As a result, 414 and 222 analytes were tentatively identified in the SSC and BSC bio-oils, respectively. The tentatively identified compound classes were acids, esters, ketones, phenols, cyclopentanones, furanes, diols, amides, pyridines, pyrroles, and hydrocarbons. Compounds with molecular weights in the range of m/z 100–300 were detected in the bio-oils using ESI(±)-Orbitrap HRMS. The N2 class was the most abundant in positive ion mode, representing 37% and 48% of relative abundance in the SSC and the BSC bio-oils, respectively. These data support the data obtained using GC?×?GC-TOFMS. The O2 heteroatom class was the most abundant for both types of bio-oil in negative ion mode, which were assigned to the carboxylic acid class previously identified by GC?×?GC-TOFMS. Lauric, palmitic, and oleic acids were found to be in high abundance, similar to the results achieved using GC?×?GC-TOFMS.Nytoft, H.P., Fyhn, M.B.W., Hovikoski, J., Rizzi, M., Abatzis, I., Tuan, H.A., Tung, N.T., Huyen, N.T., Cuong, T.X., Nielsen, L.H., 2020. Biomarkers of Oligocene lacustrine source rocks, Beibuwan-Song Hong basin junction, offshore northern Vietnam. Marine and Petroleum Geology 114, 104196. oil prone source rocks containing sapropelic Type I and mixed Types I and III kerogen are found in 233 m of the 500 m deep, fully cored ENRECA-3 well drilled on Bach Long Vi Island, located at the junction between the Beibuwan and the Song Hong basins offshore northern Vietnam. The cored succession is made up entirely by Oligocene, deep lacustrine deposits. The origin of the organic matter (OM) in 62 samples is evaluated on the basis of gas chromatography-mass spectrometry (GC-MS and GC-MS/MS). OM in 55 samples is sourced primarily from lacustrine organisms and contains abundant 4-methylsteranes, tetracyclic polyprenoids (TPP) and lycopane, and no markers for marine organic matter. The proportion of triterpanes derived from angiosperms is low in most saturated fractions and only traces of gymnosperm diterpanes are detected. In contrast, all aromatic fractions have a high proportion of compounds having an origin from both gymnosperms and angiosperms. Very high concentrations of hopanoids in both fractions suggest significant bacterial alteration of the original OM. Most samples have a high concentration of rare C31 diaromatic 8,14-secohopanes with a fluorene moiety. Low pristane/phytane (Pr/Ph) ratios indicate that anoxic/suboxic bottom water conditions existed during OM accumulation. The presence of β-carotane, gammacerane and traces of arylisoprenoids could indicate a stratified water column.OM in a few samples with lower than average hydrogen index (HI) is mainly of terrestrial origin with a higher proportion of C29 steranes, diterpanes and oleanoids and lower concentrations of both saturated and aromatic hopanes. Higher Pr/Ph, a higher C34 isohopane ratio (IHR34) and a lower homohopane index (HHI) indicate that this low-HI OM was originally deposited under more oxic conditions and subsequently transported to deeper water.Low sterane and hopane isomerization ratios show that no samples have reached the oil-window. Some novel maturity parameters for immature lacustrine samples are proposed.O’Neill, C., Marchi, S., Bottke, W., Fu, R., 2019. The role of impacts on Archaean tectonics. Geology 48, 174-178. evidence from the Pilbara craton (Australia) and Kaapvaal craton (South Africa) indicate that modern tectonic processes may have been operating at ca. 3.2 Ga, a time also associated with a high density of preserved Archaean impact indicators. Recent work has suggested a causative association between large impacts and tectonic processes for the Hadean. However, impact flux estimates and spherule bed characteristics suggest impactor diameters of <100 km at ca. 3.5 Ga, and it is unclear whether such impacts could perturb the global tectonic system. In this work, we develop numerical simulations of global tectonism with impacting effects, and simulate the evolution of these models throughout the Archaean for given impact fluxes. We demonstrate that moderate-size (～70 km diameter) impactors are capable of initiating short-lived subduction, and that the system response is sensitive to impactor size, proximity to other impacts, and also lithospheric thickness gradients. Large lithospheric thickness gradients may have first appeared at ca. 3.5–3.2 Ga as cratonic roots, and we postulate an association between Earth’s thermal maturation, cratonic root stability, and the onset of widespread sporadic tectonism driven by the impact flux at this time.GeoRef SubjectOrsi, W.D., Vuillemin, A., Rodriguez, P., Coskun, ?.K., Gomez-Saez, G.V., Lavik, G., Morholz, V., Ferdelman, T.G., 2020. Metabolic activity analyses demonstrate that Lokiarchaeon exhibits homoacetogenesis in sulfidic marine sediments. Nature Microbiology 5, 248-255. genomes of the Asgard superphylum of Archaea hold clues pertaining to the nature of the host cell that acquired the mitochondrion at the origin of eukaryotes. Representatives of the Asgard candidate phylum Candidatus Lokiarchaeota (Lokiarchaeon) have the capacity for acetogenesis and fermentation, but how their metabolic activity responds to environmental conditions is poorly understood. Here, we show that in anoxic Namibian shelf sediments, Lokiarchaeon gene expression levels are higher than those of bacterial phyla and increase with depth below the seafloor. Lokiarchaeon gene expression was significantly different across a hypoxic–sulfidic redox gradient, whereby genes involved in growth, fermentation and H2-dependent carbon fixation had the highest expression under the most reducing (sulfidic) conditions. Quantitative stable isotope probing revealed that anaerobic utilization of CO2 and diatomaceous extracellular polymeric substances by Lokiarchaeon was higher than the bacterial average, consistent with higher expression of Lokiarchaeon genes, including those involved in transport and fermentation of sugars and amino acids. The quantitative stable isotope probing and gene expression data demonstrate homoacetogenic activity of Candidatus Lokiarchaeota, whereby fermentative H2 production from organic substrates is coupled with the Wood–Ljungdahl carbon fixation pathway. The high energetic efficiency provided by homoacetogenesis8 helps to explain the elevated metabolic activity of Lokiarchaeon in this anoxic, energy-limited setting.Ortega-Hernández, J., Lerosey-Aubril, R., Pates, S., 2019. Proclivity of nervous system preservation in Cambrian Burgess Shale-type deposits. Proceedings of the Royal Society B: Biological Sciences 286, 20192370. Recent investigations on neurological tissues preserved in Cambrian fossils have clarified the phylogenetic affinities and head segmentation in pivotal members of stem-group Euarthropoda. However, palaeoneuroanatomical features are often incomplete or described from single exceptional specimens, raising concerns about the morphological interpretation of fossilized neurological structures and their significance for early euarthropod evolution. Here, we describe the central nervous system (CNS) of the short great-appendage euarthropod Alalcomenaeus based on material from two Cambrian Burgess Shale-type deposits of the American Great Basin, the Pioche Formation (Stage 4) and the Marjum Formation (Drumian). The specimens reveal complementary ventral and lateral views of the CNS, preserved as a dark carbonaceous compression throughout the body. The head features a dorsal brain connected to four stalked ventral eyes, and four pairs of segmental nerves. The first to seventh trunk tergites overlie a ventral nerve cord with seven ganglia, each associated with paired sets of segmental nerve bundles. Posteriorly, the nerve cord features elongate thread-like connectives. The Great Basin fossils strengthen the original description—and broader evolutionary implications—of the CNS in Alalcomenaeus from the early Cambrian (Stage 3) Chengjiang deposit of South China. The spatio-temporal recurrence of fossilized neural tissues in Cambrian Konservat-Lagerst?tten across North America (Pioche, Burgess Shale, Marjum) and South China (Chengjiang, Xiaoshiba) indicates that their preservation is consistent with the mechanism of Burgess Shale-type fossilization, without the need to invoke alternative taphonomic pathways or the presence of microbial biofilms.Oshlag, J.Z., Ma, Y., Morse, K., Burger, B.T., Lemke, R.A., Karlen, S.D., Myers, K.S., Donohue, T.J., Noguera, D.R., 2020. Anaerobic degradation of syringic acid by an adapted strain of Rhodopseudomonas palustris. Applied and Environmental Microbiology 86, e01888-19.: While lignin represents a major fraction of the carbon in plant biomass, biological strategies to convert the components of this heterogeneous polymer into products of industrial and biotechnological value are lacking. Syringic acid (3,5-dimethoxy-4-hydroxybenzoic acid) is a by-product of lignin degradation, appearing in lignocellulosic hydrolysates, deconstructed lignin streams, and other agricultural products. Rhodopseudomonas palustris CGA009 is a known degrader of phenolic compounds under photoheterotrophic conditions via the benzoyl coenzyme A (CoA) degradation (BAD) pathway. However, R. palustris CGA009 is reported to be unable to metabolize meta-methoxylated phenolics, such as syringic acid. We isolated a strain of R. palustris (strain SA008.1.07), adapted from CGA009, which can grow on syringic acid under photoheterotrophic conditions, utilizing it as a sole source of organic carbon and reducing power. An SA008.1.07 mutant with an inactive benzoyl-CoA reductase structural gene was able to grow on syringic acid, demonstrating that the metabolism of this aromatic compound is not through the BAD pathway. Comparative gene expression analyses of SA008.1.07 implicated the involvement of products of the vanARB operon (rpa3619, rpa3620, rpa3621), which has been described as catalyzing aerobic aromatic ring demethylation in other bacteria, in anaerobic syringic acid degradation. In addition, experiments with a vanARB deletion mutant demonstrated the involvement of the vanARB operon in anaerobic syringic acid degradation. These observations provide new insights into the anaerobic degradation of meta-methoxylated and other aromatics by R. palustris.Importance: Lignin is the most abundant aromatic polymer on Earth and a resource that could eventually substitute for fossil fuels as a source of aromatic compounds for industrial and biotechnological applications. Engineering microorganisms for the production of aromatic-based biochemicals requires detailed knowledge of the metabolic pathways for the degradation of aromatics that are present in lignin. Our isolation and analysis of a Rhodopseudomonas palustris strain capable of syringic acid degradation reveal a previously unknown metabolic route for aromatic degradation in R. palustris. This study highlights several key features of this pathway and sets the stage for a more complete understanding of the microbial metabolic repertoire required to metabolize aromatic compounds from lignin and other renewable sources.Osinski, G.R., Grieve, R.A.F., Hill, P.J.A., Simpson, S.L., Cockell, C., Christeson, G.L., Ebert, M., Gulick, S., Melosh, H.J., Riller, U., Tikoo, S.M., Wittmann, A., 2019. Explosive interaction of impact melt and seawater following the Chicxulub impact event. Geology 48, 108-112. impact of asteroids and comets with planetary surfaces is one of the most catastrophic, yet ubiquitous, geological processes in the solar system. The Chicxulub impact event, which has been linked to the Cretaceous-Paleogene (K-Pg) mass extinction marking the beginning of the Cenozoic Era, is arguably the most significant singular geological event in the past 100 million years of Earth’s history. The Chicxulub impact occurred in a marine setting. How quickly the seawater re-entered the newly formed basin after the impact, and its effects of it on the cratering process, remain debated. Here, we show that the explosive interaction of seawater with impact melt led to molten fuel–coolant interaction (MFCI), analogous to what occurs during phreatomagmatic volcanic eruptions. This process fractured and dispersed the melt, which was subsequently deposited subaqueously to form a series of well-sorted deposits. These deposits bear little resemblance to the products of impacts in a continental setting and are not accounted for in current classification schemes for impactites. The similarities between these Chicxulub deposits and the Onaping Formation at the Sudbury impact structure, Canada, are striking, and suggest that MFCI and the production of volcaniclastic-like deposits is to be expected for large impacts in shallow marine settings.Ouyang, G., She, Z., Papineau, D., Wang, X., Luo, G., Li, C., 2020. Dynamic carbon and sulfur cycling in the aftermath of the Lomagundi-Jatuli Event: Evidence from the Paleoproterozoic Hutuo Supergroup, North China Craton. Precambrian Research 337, 105549. unprecedented positive δ13C excursion in carbonates deposited between 2.2 and 2.0 Ga, known as the Lomagundi-Jatuli Event (LJE), has been documented globally and linked to the rise of atmospheric oxygen. Increasing oxidation inevitably changed the atmosphere-hydrosphere system, but few chemostratigraphic or quantitative constraints for the aftermath of this event exists. Here, we describe a ~200 m-thick carbonate succession in the Huaiyincun Formation, Hutuo Supergroup, ~2.0–1.9 Ga, from the North China Craton. There is a lithological transition from pink-purple dolostones to grey dolostones at ca. 91.6 m above the base of the Huaiyincun Formation. The former are more enriched in hematite and detrital minerals, whereas the latter contain more organic matter but almost no detrital phases. Meanwhile, the frequent occurrence of tempesite structures, along with the abrupt decline of stromatolites in the upper Huaiyincun Formation, suggest a storm-dominated environment. These distinct features within the Huaiyincun Formation reveal increased water depth during a transgression event. Two types of Raman spectra of organic matter were found in the lower and upper Huaiyincun Formation, respectively, which is proposed to be the result of variable oxidation.At 65.6 m, 26 m below the lithological transition (~91.6 m), remarkable decreases in both δ13Ccarb and δ34SCAS are observed. This discordance between C-S isotopic excursions and sedimentological and mineralogical variations argues against a seawater depth gradient effect of the δ13Ccarb and δ34SCAS curves. Instead, the decline of δ13Ccarb rather correlates with the negative δ13Ccarb excursions in ca. 2.0 Ga carbonates from Gabon and Russia, known as the Shunga-Francevillian Event (SFE). The result of the quantitatively constrained paleo-seawater [SO42?]sw suggests a crash of the seawater sulfate reservoir compared with that during the preceding LJE. However, the decreased δ34SCAS and increased CAS concentration towards the top of the study unit represent the recovery of seawater sulfate reservoir. The coordinated decline in δ34SCAS and δ13Ccarb values is likely related to enhanced oxidation of continental pyrite and organic matter in the aftermath of the LJE. The Huaiyincun Formation therefore represents a critical interval that recorded dynamic carbon and sulfur cycles after the LJE.Ovchinnikov, D.V., Pokrovskiy, O.I., Kosyakov, D.S., Bogolitsyn, K.G., Ul'yanovskii, N.V., Falev, D.I., 2020. Evaluation of temperature and pressure effects on retention in supercritical fluid chromatography on polar stationary phases. Journal of Chromatography A 1610, 460600. polar stationary phases (ethylene-bridged hybrid silica, cyanopropyl, 2-ethylpyridine, and zwitterionic sulfobetaine) have been characterized in supercritical fluid chromatography (SFC) by linear free energy relationships (LFER) method with an extended set of Abraham's descriptors. Temperature (25–55°C) and pressure (110–180?bar) effects on analyte retention, separation selectivity and LFER-coefficients of chromatographic systems have been studied using the 89 test compounds of various chemical classes and carbon dioxide – methanol (9:1 v/v) binary solvent as a mobile phase.It was found that for the selected stationary phases temperature and pressure had only moderate effects on selectivity. The retention times of all analytes decrease, as can be expected, if the pressure rises at the isothermal conditions due to the increase of the fluid density and its eluting power. The effect of temperature on retention is complicated and depends both on the chemical class of analyzed compounds and the stationary phase type.Temperature and pressure variations lead to small changes in the LFER-coefficients, and general trends observed do not depend much on the stationary phase type. It may be difficult to interpret the LFER-analysis results because of the evident, more significant chromatographic phenomena.Pais, S.C., 2019. The plasma compression fusion device—enabling nuclear fusion ignition. IEEE Transactions on Plasma Science 47, 5119-5124. plasma compression fusion device (PCFD) generates the energy gain by plasma compression-induced nuclear fusion. This concept has the capability of maximizing the product of plasma pressure and energy confinement time to maximize the energy gain, and thus give rise to fusion ignition conditions. The preferred embodiment of this original concept uses a hollow cross-duct configuration of circular cross section in which the concentrated magnetic energy flux from two pairs of opposing curved-headed counter-spinning conical structures (possibly made from an alloy of tungsten with high capacitance) whose outer surfaces are electrically charged compresses a gaseous mixture of fusion fuel into a plasma, heated to extreme temperatures and pressures. The generated high-intensity electromagnetic (EM) radiation heats the plasma and the produced magnetic fields confine it in between the counter-spinning conical structures, named the dynamic fusors (four of them-smoothly curved apex sections opposing each other in pairs). The dynamic fusors can be assemblies of electrified grids and toroidal magnetic coils, arranged within a conical structure whose outer surface is electrically charged. The cross-duct inner surface surrounding the plasma core region is also electrically charged and vibrated in an accelerated mode to minimize the flux of plasma particles (including neutrals) from impacting the PCFD surfaces and initiating a plasma quench. The fusion fuel (preferably deuterium gas) is introduced into the plasma core through the counterspinning conical structures, namely, injected through orifices in the dynamic fusor heads. There is envisioned another even more compact version of this concept, which uses accelerated vibration in a linear-duct configuration (using two counterspinning dynamic fusors only) and would best be suited for fusion power generation on aircraft, or main battle tanks. The concept uses controlled motion of electrically charged matter through accelerated vibration and/or accelerated spin subjected to smooth, yet rapid acceleration transients, to generate extremely high-energy/high-intensity EM radiation (fields of high-energy photons) which not only confines the plasma but also greatly compresses itso as to produce a high power density plasma burn, leading to ignition. The PCFD concept can produce power in the gigawatt to terawatt range (and higher) with input power in the kilowatt to megawatt range and can possibly lead to ignition (selfsustained) plasma burn. Several important practical engineering and operational issues with operating a device such as the PCFD are discussed.Paiste, K., Pellerin, A., Zerkle, A.L., Kirsim?e, K., Prave, A.R., Romashkin, A.E., Lepland, A., 2020. The pyrite multiple sulfur isotope record of the 1.98 Ga Zaonega Formation: Evidence for biogeochemical sulfur cycling in a semi-restricted basin. Earth and Planetary Science Letters 534, 116092. pyrite sulfur isotope record of the 1.98 Ga Zaonega Formation in the Onega Basin, NW Russia, has played a central role in understanding ocean-atmosphere composition and inferring worldwide fluctuations of the seawater sulfate reservoir during the pivotal times of the Paleoproterozoic Era. That, in turn, has led to a concept that Earth's atmospheric oxygen levels underwent global-scale changes. Here we present a steady-state isotope mass-balance model to gain insight into the mechanisms governing the sulfur cycle and sulfate reservoir during deposition of the organic-rich Zaonega Formation. We demonstrate that coupling between high microbial sulfate reduction rates and effective sulfate removal by pyrite precipitation can lead to Rayleigh distillation of the basinal sulfate reservoir and development of high amplitude positive δ34S excursions. This modelling approach illustrates that secular changes in sedimentary pyrite isotope trends can be explained by processes that reflect local (basin-scale) fluctuations in sulfur cycling rather than global mechanisms.Pan, H., Li, H., Chen, J., Zhang, Y., Cai, S., Huang, Y., Zheng, Y., Zhao, Y., Deng, J., 2020. A unified contact cementation theory for gas hydrate morphology detection and saturation estimation from elastic-wave velocities. Marine and Petroleum Geology 113, 104146. knowledge of hydrate morphology and accurate quantification of hydrate saturation are significant for reservoir characterization, resource exploitation and geohazards assessment. Although many of empirical or theoretical models have been developed to detect hydrate morphology and predict hydrate saturation from elastic-wave velocities, they either fail to hold true for complex morphologies or cannot provide accurate hydrate saturation estimate. In this study, we propose a unified contact cementation theory by applying the modified Hashin-Shtrikman upper and lower bounds to an extended cementation theory. By merging the cementation theory and effective medium theory, it can be used to account for four types of hydrate morphologies. Numerical modeling results provide some new insights into effects of normalized thickness of hydrate layer, friction coefficient and effective pressure on elastic-wave velocities for different morphologies, which will be helpful for analyzing the borehole stability and determining optimum production-related strategies. In addition, we propose a hydrate morphology-based inversion method by introducing the ratio of multiple hydrate morphologies from statistical analyses and apply it to the acoustic logs from the Mallik 5L-38 permafrost-related gas hydrate research well in Mackenzie Delta and other three marine wells in Nankai Trough and Hikurangi margin. The velocity-based gas hydrate saturation estimations are in good agreement with those predicted from resistivity log and Nuclear Magnetic Resonance measurement, as well as core data, confirming feasibility and applicability of our theory and inversion method, and indicating its potential in seismic characterization of gas hydrate reservoirs.Pan, Q., Yu, H., Daling, P.S., Zhang, Y., Reed, M., Wang, Z., Li, Y., Wang, X., Wu, L., Zhang, Z., Yu, H., Zou, Y., 2020. Fate and behavior of Sanchi oil spill transported by the Kuroshio during January–February 2018. Marine Pollution Bulletin 152, 110917. fate and behavior of the Sanchi oil spill during January–February 2018 was simulated by coupling an oil spill model and satellite observations with meteo-oceanographic forcing. Extensive validation tests were performed for winds, currents, surface slick, stranded oil and oil fate. A series of hindcast experiments was designed to take into account the uncertainties in oil amount, environmental forcing and model parameters. The simulations confirmed that the stable large-scale Kuroshio acted as the primary driving force. Most oil followed the Kuroshio's large-meander path, rapidly passing through the East China Sea to the waters south of Japan. The wind, appearing as the secondary transport factor, did not change the path of this large-scale current, but did contribute to the drift of surface oil. The different fates for heavy fuel oil and condensate in the accident were also compared quantitatively and discussed in this study.Panagiotopoulos, I.P., Paraschos, F., Rousakis, G., Hatzianestis, I., Parinos, C., Morfis, I., Gogou, A., 2020. Assessment of the eruptive activity and identification of the mud breccia's source in the Olimpi mud volcano field, Eastern Mediterranean. Deep Sea Research Part II: Topical Studies in Oceanography 171, 104701. though the intensity and frequency of the eruptive episodes of deep-sea mud volcanoes (MVs) substantially regulate the methane fluxes into the hydrosphere and the development of the near-seafloor sulfate zone that affects the position of the gas hydrate stability zone, these factors are not yet adequately investigated. Moreover, the evaluation of the eruptive sediment's thermal maturity may provide solid documentation of the petroleum generation potential in high depths below seafloor (bsf). Hence, the present study, through the integration of sedimentary facies analysis with hydrocarbon biomarker analysis (based on the concentrations of long-chain (C25–C35) n-alkanes, hopanes and steranes), supported by swath bathymetry data, examined five sediment cores recovered from the Gelendzhik, Moscow, Milano, Leipzig and Heraklion MVs of the Olimpi mud volcano field (OMVF) on the central Mediterranean Ridge. The main objective of this investigation was to assess the ‘modern’ eruptive activity in the OMVF and identify the mud breccia's origin and mobilization depth (based on its maturity level), and the ages of the source beds. Among the studied MVs, Milano, Leipzig and Heraklion appear ‘recently’ active, while Moscow perhaps remains in dormancy for at least one century. The eruptive activity in the OMVF seems to be, generally, vigorous and persistent, while it is linked with several source beds of variable stratigraphy or environmental condition. The multiple eruptive episodes, occurring as uninterrupted events or via pulses, create conditions that perhaps favour high releases of methane into the water column as well as the growth of the gas hydrate phase near the seafloor. The identified ‘modern’ mudflows appear thermally immature for oil generation, while they most probably originate from terrestrial source beds located not deeper than 2 km bsf. A Messinian age could be suggested for the principal sources of the very soft to soft mud breccias of the OMVF, while stratigraphic horizons of Early-Middle Miocene might be proposed as the likely major sources for the firm to very stiff mud breccias of the area.Pandey, S., Clarke, J., Nema, P., Bonaccorsi, R., Som, S., Sharma, M., Phartiyal, B., Rajamani, S., Mogul, R., Martin-Torres, J., Vaishampayan, P., Blank, J., Steller, L., Srivastava, A., Singh, R., McGuirk, S., Zorzano, M.-P., Güttler, J.M., Mendaza, T., Soria-Salinas, A., Ahmad, S., Ansari, A., Singh, V.K., Mungi, C., Bapat, N., 2020. Ladakh: diverse, high-altitude extreme environments for off-earth analogue and astrobiology research. International Journal of Astrobiology 19, 78-98. paper highlights unique sites in Ladakh, India, investigated during our 2016 multidisciplinary pathfinding expedition to the region. We summarize our scientific findings and the site's potential to support science exploration, testing of new technologies and science protocols within the framework of astrobiology research. Ladakh has several accessible, diverse, pristine and extreme environments at very high altitudes (3000–5700 m above sea level). These sites include glacial passes, sand dunes, hot springs and saline lake shorelines with periglacial features. We report geological observations and environmental characteristics (of astrobiological significance) along with the development of regolith-landform maps for cold high passes. The effects of the diurnal water cycle on salt deliquescence were studied using the ExoMars Mission instrument mockup: HabitAbility: Brines, Irradiance and Temperature (HABIT). It recorded the existence of an interaction between the diurnal water cycle in the atmosphere and salts in the soil (which can serve as habitable liquid water reservoirs). Life detection assays were also tested to establish the best protocols for biomass measurements in brines, periglacial ice-mud and permafrost melt water environments in the Tso-Kar region. This campaign helped confirm the relevance of clays and brines as interest targets of research on Mars for biomarker preservation and life detection.Paricaud, P., Ndjaka, A., Catoire, L., 2020. Prediction of the flash points of multicomponent systems: Applications to solvent blends, gasoline, diesel, biodiesels and jet fuels. Fuel 263, 116534. reformulation and the development of alternative fuels are currently topics of great interest. For example, gasoline can be reformulated for a reduction of emitted toxic pollutants. However, fossil and bio fuels are of complex compositions, and reformulation can dramatically affect the physical, chemical and safety properties of the fuel. Tools that can predict these properties are then of particular importance. In this work, we propose a general approach to accurately predict the flash points of complex fuels such as gasoline, jet fuels, diesels, and biofuels. The predictive method is based on a combination of Catoire – Naudet model with a fully predictive activity coefficient model. Excellent predictions of the flash points of mixtures are obtained for a broad variety of systems, when the COSMO-SAC dsp thermodynamic model is used. It can be used to predict the flash points of mixtures of various types of fuels: ex-fossil, first, second and third generation biofuels and their mixtures. The new approach can take into account the addition of molecules to a complex fuel when experimental measurements are not available, whatever the reasons are. The theoretical predictions confirm the experimental observation that a small amount of volatile compound such as ethanol can dramatically reduce the flash point of multicomponent fuels.Patel, A.K., Choi, Y.Y., Sim, S.J., 2020. Emerging prospects of mixotrophic microalgae: Way forward to sustainable bioprocess for environmental remediation and cost-effective biofuels. Bioresource Technology 300, 122741. bioremediation becoming most fascinating to produce biomass as biofuels feedstock while remediating wastes, also improving carbon-footprint through carbon capturing and utilization (CCU) technology. Non-algae process however offers effective treatment but metabolic CO2 emission is major drawback towards sustainable bioprocess. Mixotrophic cultivation strategy (MCS) enables to treat organic and inorganic wastes which broadly extend microalgae application towards cleaner and sustainable bioeconomy. Latest focus of global think-tanks to encourage bioprocess holding promise of sustainability via CCU ability as important trait. Several high CO2 emitting industries forced to improve their carbon-footprints. MCS driven microalgae treatment could be best solution for those industries. This review covers recent updates on MCS applications for waste-to-value (biofuels) and environment remediation. Moreover, recommendations to fill knowledge gaps, and commercial algal biofuel could be cost-effectiveness and sustainable technology for biocircular economy if fuelled by waste streams from other industries.Paver, S.F., Newton, R.J., Coleman, M.L., 2020. Microbial communities of the Laurentian Great Lakes reflect connectivity and local biogeochemistry. Environmental Microbiology 22, 433-446. Laurentian Great Lakes are a vast, interconnected freshwater system spanning strong physicochemical gradients, thus constituting a powerful natural laboratory for addressing fundamental questions about microbial ecology and evolution. We present a comparative analysis of pelagic microbial communities across all five Laurentian Great Lakes, focusing on Bacterial and Archaeal picoplankton characterized via 16S rRNA amplicon sequencing. We collected samples throughout the water column from the major basins of each lake in spring and summer over 2?years. Two oligotypes, classified as LD12 (Alphaproteobacteria) and acI‐B1 (Actinobacteria), were among the most abundant in every sample. At the same time, microbial communities showed distinct patterns with depth during summer stratification. Deep hypolimnion samples were frequently dominated by a Chloroflexi oligotype that reached up to 19% relative abundance. Stratified surface communities differed between the colder, less productive upper lakes (Superior, Michigan, Huron) and warmer, more productive lower lakes (Erie, Ontario), in part due to an Actinobacteria oligotype (acI‐C2) that averaged 7.7% of sequences in the lower lakes but <0.2% in the upper lakes. Together, our findings suggest that both hydrologic connectivity and local selective pressures shape microbial communities in the Great Lakes and establish a framework for future investigations.Payandi-Rolland, D., Shirokova, L.S., Nakhle, P., Tesfa, M., Abdou, A., Causserand, C., Lartiges, B., Rols, J.-L., Guérin, F., Bénézeth, P., Pokrovsky, O.S., 2020. Aerobic release and biodegradation of dissolved organic matter from frozen peat: Effects of temperature and heterotrophic bacteria. Chemical Geology 536, 119448. the conditions of dissolved organic matter (DOM) release from thawing peat in the Arctic regions and identifying the pathways of processing DOM by soil and aquatic heterotrophic bacteria are critical in the context of rapid climate change. Until now, experimental approaches did not allow quantitative predictions of temperature and biota effects on carbon release from peat in permafrost-affected aquatic environments. In this study, we incubated frozen peat and its aqueous leachate at various temperatures (4, 25 or 45 °C), with and without culturable heterotrophic bacteria Iodobacter sp., extracted from thermokarst lakes, to quantify the release and the removal rate of organic carbon (OC) with time. The metabolic diversity of the native microbial community associated with the substrates involved in OC processing was also characterized. Transmission electron microscopy revealed that, after degradation, the associated bacteria are mostly located in the inner parts of plant cells, and that the degradation of organic matter around bacteria is more pronounced at 4 and 25 °C compared to 45 °C. The metabolic diversity of heterotrophic bacteria was equally high at 4 and 25 °C, but lower at 45 °C. Regardless of the microbial consortium (native community alone or with added culturable heterotrophs), both the OC release from peat and the OC removal from peat leachate by bacteria were similar at 4 and 25 °C. Very low apparent activation energies of DOM biodegradation between 4 and 25 °C (?4.23 ± 12.3 kJ mol?1) suggest that the short-period of surface water warming in summer would have an insignificant effect on DOM microbial processing. Such duration (1–3 weeks) is comparable with the water residence time in peat depressions and permafrost subsidences, where peat degradation and DOM microbial processing occur. This questions the current paradigm of a drastic effect of temperature rise on organic carbon release from frozen peatlands, and should be considered for modelling short-term climate impacts in these regions.Payne, R.C., Brownlee, D., Kasting, J.F., 2020. Oxidized micrometeorites suggest either high pCO2 or low pN2 during the Neoarchean. Proceedings of the National Academy of Sciences 117, 1360.: Paleosols (ancient soils) have been used to estimate CO2 concentrations during the Archean Eon, 4.0 to 2.5 Ga. However, different paleosol studies disagree with each other and with climate model estimates for ancient CO2 levels. Oxidized iron micrometeorites dated at 2.7 Ga represent a new CO2 proxy with which to compare. These meteorites suggest that CO2 constituted 25 to 50% of the atmosphere at that time. This is easiest to explain if the N2 partial pressure was lower than today so that the atmospheric greenhouse effect was modest and the climate was cool, consistent with evidence for contemporaneous glaciation.Abstract: Tomkins et al. [A. G. Tomkins et al., Nature 533, 235–238 (2016)] suggested that iron oxides contained in 2.7-Ga iron micrometeorites can be used to determine the concentration of O2 in the Archean upper atmosphere. Specifically, they argued that the presence of magnetite in these objects implies that O2 must have been near present-day levels (～21%) within the altitude range where the micrometeorites were melted during entry. Here, we reevaluate their data using a 1D photochemical model. We find that atomic oxygen, O, is the most abundant strong oxidant in the upper atmosphere, rather than O2. But data from shock tube experiments suggest that CO2 itself may also serve as the oxidant, in which case micrometeorite oxidation really constrains the CO2/N2 ratio, not the total oxidant abundance. For an atmosphere containing 0.8 bar of N2, like today, the lower limit on the CO2 mixing ratio is ～0.23. This would produce a mean surface temperature of ～300 K at 2.7 Ga, which may be too high, given evidence for glaciation at roughly this time. If pN2 was half the present value, and warming by other greenhouse gases like methane was not a major factor, the mean surface temperature would drop to ～291 K, consistent with glaciation. This suggests that surface pressure in the Neoarchean may need to have been lower—closer to 0.6 bar—for CO2 to have oxidized the micrometeorites. Ultimately, iron micrometeorites may be an indicator for ancient atmospheric CO2 and surface pressure; and could help resolve discrepancies between climate models and existing CO2 proxies such as paleosols.Peng, C., Tang, Y., Yang, H., He, Y., Liu, Y., Liu, D., Qian, Y., Lu, L., 2020. Time- and compound-dependent microbial community compositions and oil hydrocarbon degrading activities in seawater near the Chinese Zhoushan Archipelago. Marine Pollution Bulletin 152, 110907. microorganisms play an irreplaceable role in removing spilled oil. Zhoushan archipelago has one of the busiest ports and oil stockpiles in China. However, little is known about which and how fast oil-degrading microorganisms could biodegrade spilled oil here. By combining 14C-/3H-based radiotracer assays and MiSeq sequencing, we report the successive pattern of microbial oil-degrading activities and community compositions. The biodegradation rates of alkanes and PAHs (Polycyclic Aromatic Hydrocarbons) were significantly stimulated by oil addition, and reached their maximum after incubation for 3 and 7 days, respectively. Meanwhile, the abundances of alkB and phnAc genes increased and the bacterial communities continuously shifted. Potential oil-degrading bacteria Alcanivorax, Erythrobacter were the dominant degraders by day 3, whereas the dominant degraders shifted to C1-B045, Alteromonas, Pseudohongiella in the later period. These results provide valuable insights into the cooperative system of the versatile oil-degrading bacteria in successively biodegrading complex oil hydrocarbons in oil spills.Pereira, E., Meirelles, A.J.A., Maximo, G.J., 2020. Predictive models for physical properties of fats, oils, and biodiesel fuels. Fluid Phase Equilibria 508, 112440. properties determine in large extent the application of fats and oils, considering products’ formulation, and the design of equipment and processes in the food industry. These lipids have also been highly significant in the development of the bioenergy industry due to the increasing demand for biodiesel worldwide, whose physical properties should attend strict standards specifications. Fats, oils, and biodiesel are multicomponent systems which present complex phase equilibrium profile. Thus, the phase equilibrium behavior of these lipids plays a crucial role in their physicochemical properties. In this context, several thermodynamic modeling approaches have been used to predict the behavior of lipids and design products with desired properties. In this paper, we critically review and summarize the current state of knowledge of predictive modeling approaches used for the calculation of physicochemical properties of fats, oils, and biodiesel with a special focus on properties related to product design, such as melting/crystallization behavior and viscosity. The most remarkable publications dealing with predictive modeling are analyzed, and the underlying thermodynamic concepts used in those approaches, as well as their limitations, are assessed. Finally, we discuss future perspectives and indicate challenges to improve the research area.Pérez-Guaita, D., Quintás, G., Kuligowski, J., 2020. Discriminant analysis and feature selection in mass spectrometry imaging using constrained repeated random sampling - Cross validation (CORRS-CV). Analytica Chimica Acta 1097, 30-36. identification of biomarkers through Mass spectrometry imaging (MSI) is gaining popularity in the clinical field. However, considering the complexity of spectral and spatial variables faced, data mining of the hyperspectral images can be troublesome. The discovery of markers generally depends on the creation of classification models which should be validated to ensure the statistical significance of the discriminants m/z detected. Internal validation using resampling methods such as cross validation (CV) are widely used for model selection, the estimation of its generalization performance and biomarker discovery when sample sizes are limited and an independent test set is not available. Here, we introduce for first time the use of Constrained Repeated Random Subsampling CV (CORRS-CV) on multi-images for the validation of classification models on MSI. Although several aspects must be taken into account (e.g. image size, CORRS-CV?value, the similarity across spatially close pixels, the total computation time), CORRS-CV provides more accurate estimates of the model performance than k-fold CV using of biological replicates to define the data split when the number of biological replicates is scarce and holding images back for testing is a waste of valuable information. Besides, the combined use of CORRS-CV and rank products increases the robustness of the selection of discriminant features as candidate biomarkers which is an important issue due to the increased biological, environmental and technical variabilities when analysing multiple images, especially from human tissues collected in clinical studies.Perini, L., Gostin?ar, C., Gunde-Cimerman, N., 2019. Fungal and bacterial diversity of Svalbard subglacial ice. Scientific Reports 9, 20230. composition of fungal and bacterial communities in three polythermal glaciers and associated aquatic environments in Kongsfjorden, Svalbard was analysed using a combination of cultivation and amplicon sequencing. 109 fungal strains belonging to 30 mostly basidiomycetous species were isolated from glacial samples with counts up to 103 CFU/100?ml. Glaciozyma-related taxon and Phenoliferia psychrophenolica were the dominant species. Unexpectedly, amplicon sequencing uncovered sequences of Chytridiomycota in all samples and Rozellomycota in sea water, lake water, and tap water. Sequences of Malassezia restricta and of the extremely halotolerant Hortaea werneckii were also found in subglacial habitats for the first time. Overall, the fungal communities within a glacier and among glaciers were diverse and spatially heterogenous. Contrary to this, there was a large overlap between the bacterial communities of different glaciers, with Flavobacterium sp. being the most frequently isolated. In amplicon sequencing Actinobacteria and Proteobacteria sequences were the most abundant.Petrone, P., Pucci, P., Niola, M., Baxter, P.J., Fontanarosa, C., Giordano, G., Graziano, V., Sirano, F., Amoresano, A., 2020. Heat-induced brain vitrification from the Vesuvius eruption in c.e. 79. New England Journal of Medicine 382, 383-384.: The rapid rise in extreme heat during the Vesuvius eruption in c.e. 79 resulted in the conversion of human tissue to glass (vitrification). Among the recent finds at Herculaneum was tissue residue that could be identified by chemical methods as vitrified brain tissue.Petzold, A., Lu, C.-H., Groves, M., Gobom, J., Zetterberg, H., Shaw, G., O’Connor, S., 2020. Protein aggregate formation permits millennium-old brain preservation. Journal of The Royal Society Interface 17, 20190775.. 0775Human proteins have not been reported to survive in free nature, at ambient temperature, for long periods. Particularly, the human brain rapidly dissolves after death due to auto-proteolysis and putrefaction. The here presented discovery of 2600-year-old brain proteins from a radiocarbon dated human brain provides new evidence for extraordinary long-term stability of non-amyloid protein aggregates. Immunoelectron microscopy confirmed the preservation of neurocytoarchitecture in the ancient brain, which appeared shrunken and compact compared to a modern brain. Resolution of intermediate filaments (IFs) from protein aggregates took 2–12 months. Immunoassays on micro-dissected brain tissue homogenates revealed the preservation of the known protein topography for grey and white matter for type III (glial fibrillary acidic protein, GFAP) and IV (neurofilaments, Nfs) IFs. Mass spectrometry data could be matched to a number of peptide sequences, notably for GFAP and Nfs. Preserved immunogenicity of the prehistoric human brain proteins was demonstrated by antibody generation (GFAP, Nfs, myelin basic protein). Unlike brain proteins, DNA was of poor quality preventing reliable sequencing. These long-term data from a unique ancient human brain demonstrate that aggregate formation permits for the preservation of brain proteins for millennia.Pfeiffer, D., Schüler, D., 2020. Quantifying the benefit of a dedicated “magnetoskeleton” in bacterial magnetotaxis by live-cell motility tracking and soft agar swimming assay. Applied and Environmental Microbiology 86, e01976-19.: The alphaproteobacterium Magnetospirillum gryphiswaldense has the intriguing ability to navigate within magnetic fields, a behavior named magnetotaxis, governed by the formation of magnetosomes, intracellular membrane-enveloped crystals of magnetite. Magnetosomes are aligned in chains along the cell’s motility axis by a dedicated multipart cytoskeleton (“magnetoskeleton”); however, precise estimates of its significance for magnetotaxis have not been reported. Here, we estimated the alignment of strains deficient in various magnetoskeletal constituents by live-cell motility tracking within defined magnetic fields ranging from 50 μT (reflecting the geomagnetic field) up to 400 μT. Motility tracking revealed that ΔmamY and ΔmamK strains (which assemble mispositioned and fragmented chains, respectively) are partially impaired in magnetotaxis, with approximately equal contributions of both proteins. This impairment was reflected by a required magnetic field strength of 200 μT to achieve a similar degree of alignment as for the wild-type strain in a 50-μT magnetic field. In contrast, the ΔmamJ strain, which predominantly forms clusters of magnetosomes, was only weakly aligned under any of the tested field conditions and could barely be distinguished from a nonmagnetic mutant. Most findings were corroborated by a soft agar swimming assay to analyze magnetotaxis based on the degree of distortion of swim halos formed in magnetic fields. Motility tracking further revealed that swimming speeds of M. gryphiswaldense are highest within the field strength equaling the geomagnetic field. In conclusion, magnetic properties and intracellular positioning of magnetosomes by a dedicated magnetoskeleton are required and optimized for bacterial magnetotaxis and most efficient locomotion within the geomagnetic field.Importance: In Magnetospirillum gryphiswaldense, magnetosomes are aligned in quasi-linear chains in a helical cell by a complex cytoskeletal network, including the actin-like MamK and adapter MamJ for magnetosome chain concatenation and segregation and MamY to position magnetosome chains along the shortest cellular axis of motility. Magnetosome chain positioning is assumed to be required for efficient magnetic navigation; however, the significance and contribution of all key constituents have not been quantified within defined and weak magnetic fields reflecting the geomagnetic field. Employing two different motility-based methods to consider the flagellum-mediated propulsion of cells, we depict individual benefits of all magnetoskeletal constituents for magnetotaxis. Whereas lack of mamJ resulted almost in an inability to align cells in weak magnetic fields, an approximately 4-fold-increased magnetic field strength was required to compensate for the loss of mamK or mamY. In summary, the magnetoskeleton and optimal positioning of magnetosome chains are required for efficient magnetotaxis.Pham, H.-T.-T., Kim, H.-W., Han, S., Ryu, B., Doan, T.-P., An, J.-P., Tran, V.-O., Oh, W.-K., 2019. Development of a building block strategy to target the classification, identification, and metabolite profiling of oleanane triterpenoids in Gymnema sylvestre using UHPLC-qTOF/MS. Journal of Natural Products 82, 3249-3266. major class of bioactive metabolites in Gymnema sylvestre, a popular Ayurvedic medicinal plant for the treatment of diabetes mellitus, is oleanane triterpenoids. In this study, a targeted, biosynthesis-inspired approach using UHPLC-qTOF/MS was implemented to elucidate the whole chemical profile of this plant for the standardization of the Vietnamese G. sylvestre variety. The known compounds were first determined to identify the building blocks of the biosynthetic intermediates and the construction rules for synthesizing oleanane triterpenoids in the plant. These blocks were recombined to build a virtual library of all reasonable compounds consistent with the deduced construction rules. Various techniques, including relative mass defect filtering, multiple key ion analysis, mass fragmentation analysis, and comparison with standard references, were applied to determine the presence of these predicted compounds. Conventional isolation and structure elucidation of six of the new compounds were carried out to identify the new building blocks and validate the assignments. Consequently, 119 peaks were quickly assigned to oleanane triterpenoids, and among them, 77 peaks were predicted to be new compounds based on their molecular formulas and mass fragmentation patterns. All the identified metabolites were then classified into different layers to analyze their logical relationships, and a multilayered chemical profile of the oleanane triterpenoids was constructed. This new approach is expected to be practical for characterizing structures of modular secondary metabolites, such as triterpenoid saponins, and for proposing biosynthetic relationships among compounds of the same class of metabolites in medicinal plants.Philips, J., 2020. Extracellular electron uptake by acetogenic bacteria: Does H2 consumption favor the H2 evolution reaction on a cathode or metallic iron? Frontiers in Microbiology 10, 2997. doi: 10.3389/fmicb.2019. 02997. acetogenic bacteria are capable of using solid electron donors, such as a cathode or metallic iron [Fe(0)]. Acetogens using a cathode as electron donor are of interest for novel applications such as microbial electrosynthesis, while microorganisms using Fe(0) as electron donor cause detrimental microbial induced corrosion. The capacity to use solid electron donors strongly differs between acetogenic strains, which likely relates to their extracellular electron transfer (EET) mechanism. Different EET mechanisms have been proposed for acetogenic bacteria, including a direct mechanism and a H2 dependent indirect mechanism combined with extracellular hydrogenases catalyzing the H2 evolution reaction on the cathode or Fe(0) surface. Interestingly, low H2 partial pressures often prevail during acetogenesis with solid electron donors. Hence, an additional mechanism is here proposed: the maintenance of low H2 partial pressures by microbial H2 consumption, which thermodynamically favors the H2 evolution reaction on the cathode or Fe(0) surface. This work elaborates how the H2 partial pressure affects the H2 evolution onset potential and the H2 evolution rate on a cathode, as well as the free energy change of the anoxic corrosion reaction. In addition, the H2 consumption characteristics, i.e., H2 threshold (thermodynamic limit for H2 consumption) and H2 consumption kinetic parameters, of acetogenic bacteria are reviewed and evidence is discussed for strongly different H2 consumption characteristics. Different acetogenic strains are thus expected to maintain different H2 partial pressures on a cathode or Fe(0) surface, while those that maintain lower H2 partial pressures (lower H2 threshold, higher H2 affinity) more strongly increase the H2 evolution reaction. Consequently, I hypothesize that the different capacities of acetogenic bacteria to use solid electron donors are related to differences in their H2 consumption characteristics. The focus of this work is on acetogenic bacteria, but similar considerations are likely also relevant for other hydrogenotrophic microorganisms.Phillips, E., Gilevska, T., Horst, A., Manna, J., Seger, E., Lutz, E.J., Norcross, S., Morgan, S.A., West, K.A., Mack, E.E., Dworatzek, S., Webb, J., Sherwood Lollar, B., 2020. Transformation of chlorofluorocarbons investigated via stable carbon compound-specific isotope analysis. Environmental Science & Technology 54, 870-878. isotope analysis (CSIA) is a valuable tool in contaminant remediation studies. Chlorofluorocarbons (CFCs) are ozone-depleting substances previously thought to be persistent in groundwater under most geochemical conditions but more recently have been found to (bio)transform in some laboratory experiments. To date, limited applications of CSIA to CFCs have been undertaken. Here, biotransformation-associated carbon isotope enrichment factors, εC,bulk for CFC-113 (εC,bulk = ?8.5 ± 0.4‰) and CFC-11 (εC,bulk = ?14.5 ± 1.9‰), were determined. δ13C signatures of pure-phase CFCs and hydrochlorofluorocarbons were measured to establish source signatures. These findings were applied to investigate potential in situ CFC transformation in groundwater at a field site, where carbon isotope fractionation of CFC-11 suggests naturally occurring biotransformation by indigenous microorganisms. The maximum extent of CFC-11 transformation is estimated to be up to 86% by an approximate calculation using the Rayleigh concept. CFC-113 δ13C values in contrast were not resolvably different from pure-phase sources measured to date, demonstrating that CSIA can aid in identifying which compounds may, or may not, be undergoing reactive processes at field sites. Science and public attention remains focused on CFCs, as unexplained source inputs to the atmosphere have been recently reported, and the potential for CFC biotransformation in surface and groundwaters remains unclear. This study proposes δ13C CSIA as a novel application to study the fate of CFCs in groundwater.Phrampus, B.J., Lee, T.R., Wood, W.T., 2020. A global probabilistic prediction of cold seeps and associated SEAfloor FLuid ExpulsionAnomalies (SEAFLEAs). Geochemistry, Geophysics, Geosystems 21, e2019GC008747. newly compiled, open‐source database of focused fluid flow sites (e.g., cold seeps) and associated SEAfloor FLuid Expulsion Anomalies (SEAFLEAs) reveals a variable distribution of anomalies across global continental margins. The SEAFLEA distribution is heavily biased toward North American continental margins, with most observations between 100‐ and 200‐m water depth globally, and with an equal distribution between active and passive margins. Using a machine learning classification methodology based on outlier detection algorithms, we predict the probability of encountering a SEAFLEA globally. Results show the highest probability in regions with multiple SEAFLEA observations and parametrically similar regions concentrated on continental margins. In general, geologic, biologic, and chemical predictors are the best predictors of SEAFLEAs. We validate our results using a random and geospatial validation technique that reveals our methods are robust to random variations in observations, but that certain margins, such as the Svalbard Margin, represent parametrically distinct locals. These distinct regions have control over the global distribution of predicted anomalies due to their unique features. Our final prediction on a global 5 × 5 arc minute grid reveals that the average probability of encountering a SEAFLEA is 33.1 ± 17.7% on active margins and 31.2 ± 18.9% on passive margins, showing equal likelihood of encountering fluid expulsion between passive and active margins. Therefore, the lateral compaction on active margins does not increase the likelihood of fluid expulsion relative to the predominantly vertical compaction on passive margins. These results however say nothing of the fluid flux rates or density of expulsion features.Pichon, V., Delaunay, N., Combès, A., 2020. Sample preparation using molecularly imprinted polymers. Analytical Chemistry 92, 16-33. the advances in the development of new instruments and highly sensitive analytical methods based on gas, liquid, or supercritical fluid chromatography coupled to various detectors including high-resolution mass spectrometry (MS) that can be associated with different ionization sources, a pretreatment is usually necessary in order to extract and isolate the analytes of interest from complex samples before their determination. Solid-phase extraction (SPE) is routinely used for the extraction or purification of compounds from liquid samples or solid matrix extracts. Despite their attractive features, the classical SPE sorbents retain analytes by nonselective hydrophobic (with alkyl-bonded silicas, polymers, carbonaceous sorbents,...) or polar interactions (with silica, amino-bonded silica, alumina,...) that lead to partial coextraction of interfering substances that may cause matrix effects even with a specific detector such as a mass spectrometer. To enhance the extraction selectivity of the target analytes, new materials involving a mechanism of molecular recognition were developed. They include immunosorbents based on the high affinity and selectivity of antigen–antibody interactions allowing a selective extraction of the target analyte and compounds having a similar structure.(1?4) Nevertheless, the development of an immunosorbent is time-consuming and relatively expensive. A similar behavior can also be obtained using aptamers, i.e., DNA or RNA sequences with high specificity toward given compounds. The resulting oligosorbents were recently successfully applied to the selective extraction of different target analytes from biological fluids and food samples.(5?8) Once the sequence is available, the development of an oligosorbent is less expensive than an immunosorbent. However, despite their high potential, a limited number of sequences is, to date, available. An alternative is to develop molecularly imprinted polymers (MIPs). These sorbents are synthetic polymeric materials possessing specific cavities designed for a template molecule involving a retention mechanism based on molecular recognition. The MIPs have been already successfully used in several fields, such as sensors,(9,10) biomimetic catalyst in organic synthesis,(11) drug delivery,(12) and separation of structural analogues or enantiomers(13) in liquid chromatography (LC)(14?16) and capillary electrophoresis.(15?18) The use of MIPs as selective sorbents for sample pretreatment was described for the first time by Sellergren and co-workers in 1994 and concerned the development of a MIP for the solid-phase extraction of pentamidine from urine.(19) Since this pioneer work, there has been a growing interest in these polymers for extraction purposes. Initially mainly developed for the selective recognition of small molecules, such as drugs, pesticides, or other environmental pollutants,(20?23) they are now developed, as illustrated in recent reviews, for the recognition of proteins(24?26) or even microorganisms.(27) While the nature of the targets for which MIPs have been developed has evolved, so has the format of the extraction devices. Indeed, although MIPs have been mainly applied to the selective extraction or cleaning of target analytes from various complex samples by introducing them in a cartridge to carry out off-line SPEs, a strong trend toward miniaturized extraction devices has been observed over the past decade. The tendency is to develop new synthesis pathways to obtain particles of controlled sizes, fibers, stir-bars, or membranes, thus allowing their use in dispersive SPE (dSPE), solid-phase microextraction (SPME), or stir bar sorptive extraction (SBSE). This change of format is not only a reduction in size but also implies changing the polymerization modes which, despite the small size of the devices, must make it possible to maintain sufficient binding capacity. The modification of the polymerization conditions is also required when developing MIPs for proteins because of their lack of stability in conventional polymerization solvents. Based on the works published over the past 2 years for numerous target molecules, as reported in Figure 1, this paper aims to review the new strategies of development of MIPs in different formats dedicated to various extraction methods (whose distribution in terms of published work is given in Figure 2), often treated independently in the previously mentioned reviews, for both small organic molecules and proteins for which there are high expectations for replacing antibodies.Piehowski, P.D., Zhu, Y., Bramer, L.M., Stratton, K.G., Zhao, R., Orton, D.J., Moore, R.J., Yuan, J., Mitchell, H.D., Gao, Y., Webb-Robertson, B.-J.M., Dey, S.K., Kelly, R.T., Burnum-Johnson, K.E., 2020. Automated mass spectrometry imaging of over 2000 proteins from tissue sections at 100-μm spatial resolution. Nature Communications 11, 8. tissues exhibit complex spatial heterogeneity that directs the functions of multicellular organisms. Quantifying protein expression is essential for elucidating processes within complex biological assemblies. Imaging mass spectrometry (IMS) is a powerful emerging tool for mapping the spatial distribution of metabolites and lipids across tissue surfaces, but technical challenges have limited the application of IMS to the analysis of proteomes. Methods for probing the spatial distribution of the proteome have generally relied on the use of labels and/or antibodies, which limits multiplexing and requires a priori knowledge of protein targets. Past efforts to make spatially resolved proteome measurements across tissues have had limited spatial resolution and proteome coverage and have relied on manual workflows. Here, we demonstrate an automated approach to imaging that utilizes label-free nanoproteomics to analyze tissue voxels, generating quantitative cell-type-specific images for >2000 proteins with 100-?m spatial resolution across mouse uterine tissue sections preparing for blastocyst implantation.Pietzsch, R., Tedeschi, L.R., Oliveira, D.M., dos Anjos, C.W.D., Vazquez, J.C., Figueiredo, M.F., 2020. Environmental conditions of deposition of the Lower Cretaceous lacustrine carbonates of the Barra Velha Formation, Santos Basin (Brazil), based on stable carbon and oxygen isotopes: A continental record of pCO2 during the onset of the Oceanic Anoxic Event 1a (OAE 1a) interval? Chemical Geology 535, 119457. study presents new stable carbon and oxygen isotope data from Lower Cretaceous lacustrine carbonate rock samples recovered from a well drilled in the Santos Basin, offshore southeast Brazil. These samples represent a record of a continental environment just prior to the opening of the South Atlantic Ocean and the ultimate break-up of Gondwanaland. The geochemical data, along with carbonate mineralogy, indicate repeated cycles of lake level variation that could be attributed to climatic oscillations. Despite the absence of correlations between δ13C and δ18O values, facies analysis and the isotopic and mineralogical data suggest that lake hydrology was essentially closed for most of the depositional interval studied here. The existence of persisting trends of nearly constant δ13C values with a spread in δ18O values though, suggests long water residence times in the palaeolake, equilibrium between atmosphere and lake water CO2, as well as significant evaporation of water. The overall geological model that emerges unveils a more comprehensive picture of the depositional conditions that favoured the continuity of a significant carbonate factory in the middle of the Gondwanan continent, corroborating previous studies that suggested the lasting existence of a large and somewhat shallow endorheic lake in the area during the Early Cretaceous. As a result of this recorded trend strongly suggesting equilibrium between lake waters DIC (dissolved inorganic carbon) reservoir and atmospheric CO2, the data are most consistent with lacustrine deposition rather than precipitation of travertine, contrasting with some suggestions for the genesis of the carbonates of the Barra Velha Formation. Finally, this apparent equilibrium with the atmosphere likely left a preserved record in the continental carbonates of the final stages that preceded a major global environmental disturbance associated with an increase in atmospheric CO2, known for this time as the Oceanic Anoxic Event (OAE) 1a. If this is correct, it also helps to put further time constraints on this studied interval, which should not be younger than Barremian age, and to provide a regional continental perspective on a global event.Pillot, G., Davidson, S., Auria, R., Combet-Blanc, Y., Godfroy, A., Liebgott, P.-P., 2020. Production of current by syntrophy between exoelectrogenic and fermentative hyperthermophilic microorganisms in heterotrophic biofilm from a deep-sea hydrothermal chimney. Microbial Ecology 79, 38-49. study the role of exoelectrogens within the trophic network of deep-sea hydrothermal vents, we performed successive subcultures of a hyperthermophilic community from a hydrothermal chimney sample on a mix of electron donors in a microbial fuel cell system. Electrode (the electron acceptor) was swapped every week to enable fresh development from spent media as inoculum. The MFC at 80 °C yielded maximum current production increasing from 159 to 247 mA m?2 over the subcultures. The experiments demonstrated direct production of electric current from acetate, pyruvate, and H2 and indirect production from yeast extract and peptone through the production of H2 and acetate from fermentation. The microorganisms found in on-electrode communities were mainly affiliated to exoelectrogenic Archaeoglobales and Thermococcales species, whereas in liquid media, the communities were mainly affiliated to fermentative Bacillales and Thermococcales species. The work shows interactions between fermentative microorganisms degrading complex organic matter into fermentation products that are then used by exoelectrogenic microorganisms oxidizing these reduced compounds while respiring on a conductive support. The results confirmed that with carbon cycling, the syntrophic relations between fermentative microorganisms and exoelectrogens could enable some microbes to survive as biofilm in extremely unstable conditions.Plecerová, A., Kaupová Drtikolová, S., ?merda, J., Stloukal, M., Velemínsk?, P., 2020. Dietary reconstruction of the Moravian Lombard population (Kyjov, 5th–6th centuries AD, Czech Republic) through stable isotope analysis (δ13C, δ15N). Journal of Archaeological Science: Reports 29, 102062. diet of the Lombard (Langobard) population of the Kyjov site (5th-6th centuries AD, Moravia, Czech Republic) was reconstructed from carbon (δ13C) and nitrogen (δ15N) isotopic values in the bone collagen from 73 human and 19 faunal samples. Results indicate that the diet of the Lombard population sample was based on C3 plants and animal proteins. The presence of three outliers with δ13C values above ?18‰, however, suggests that millet was accessible and consumed by at least some members of the community in substantial quantities. Given the dating and exogenous character of the grave goods, these individuals are most probably members of the indigenous population of Moravia who grew millet before the arrival of the Lombards. The Lombard population shows a sex-based difference in the consumption of animal protein, with males on average showing higher values of δ15N than females. These findings match well with the (limited) prior isotopic research into the Central European phase of the Lombard migration. This study thus significantly enhances our knowledge about general trends in the dietary behaviour of Central European Lombards.Pouteau, R., Trueba, S., Isnard, S., 2019. Retracing the contours of the early angiosperm environmental niche. Annals of Botany 125, 49-57. and Aims: Our aim was to understand the environmental conditions of the emergence and radiation of early angiosperms. Such a question has long remained controversial because various approaches applied in the past have drawn conflicting images of early angiosperm ecology.Methods: We provided a new perspective on the question by using support vector machines to model the environmental niche of 51 species belonging to ten genera of extant lineages that diverged early during angiosperm evolution (basal angiosperms). Then, we analysed the resulting pattern of niche overlap and determined whether this pattern deviates from what would be expected on the basis of a null model or whether it might mirror a legacy of a common primitive niche based on a phylogenetic reconstruction.Key Results: The niche of three-quarters of the species and all genera converged towards tropical montane cloud forests (TMCFs). The latitudinal pattern of basal angiosperm richness indeed culminated in the tropics, and the elevational pattern revealed a humpback curve peaking between 2000 m and 3500 m when accounting for the effect of area. At first glance, this diversity pattern does not significantly differ from null predictions. However, we revealed a tendency for the basal-most taxa to occur in TMCFs so that phylogenetic reconstructions indicated that the niche of the common ancestor of the sampled basal angiosperms had a probability of 0.85–0.93 to overlap with TMCFs.Conclusions: Our new approach indicates that the environmental convergence of extant basal angiosperms towards TMCFs would reflect a legacy of an ancestral niche from which the least basal taxa would have diverged following a random pattern under geometric constraints.Preston, L.J., Barcenilla, R., Dartnell, L.R., Kucukkilic-Stephens, E., Olsson-Francis, K., 2019. Infrared spectroscopic detection of biosignatures at Lake Tírez, Spain: Implications for Mars. Astrobiology 20, 15-25. detection of potential biosignatures with mineral matrices is part of a multifaceted approach in the search for life on other planetary bodies. The 2020 ExoMars Rosalind Franklin rover includes within its payload three IR spectrometers in the form of ISEM (Infrared Spectrometer for ExoMars), MicrOmega, and Ma-MISS (Mars Multispectral Imager for Subsurface Studies). The use of this technique in the detection and characterization of biosignatures is of great value. Organic materials are often co-deposited in terrestrial evaporites and as such have been proposed as relevant analogs in the search for life on Mars. This study focuses on Ca-sulfates collected from the hypersaline Tírez Lake in Spain. Mid infrared and visible near infrared analysis of soils, salt crusts, and crystals with green and red layering indicative of microbial colonization of the samples was acquired from across the lake and identified the main mineral to be gypsum with inputs of carbonate and silica. Organic functional groups that could be attributed to amides and carboxylic acids were identified as well as chlorophyll; however, due to the strong mineralogical absorptions observed, these were hard to unambiguously discern. Taxonomical assignment demonstrated that the archaeal community within the samples was dominated by the halophilic extremophile Halobacteriaceae while the bacterial community was dominated by the class Nocardiaceae. The results of this research highlight that sulfates on Mars are a mixed blessing, acting as an effective host for organic matter preservation but also a material that masks the presence of organic functional groups when analyzed with spectroscopic tools similar to those due to fly on the 2020 ExoMars rover. A suite of complementary analytical techniques therefore should be used to support the spectral identification of any candidate extraterrestrial biosignatures.Priharto, N., Ronsse, F., Yildiz, G., Heeres, H.J., Deuss, P.J., Prins, W., 2020. Fast pyrolysis with fractional condensation of lignin-rich digested stillage from second-generation bioethanol production. Journal of Analytical and Applied Pyrolysis 145, 104756. lignin-rich feedstock (i.e. stillage) obtained from bioethanol production was subjected to fast pyrolysis in a modified fluidised bed reactor at 430 °C, 480 °C, and 530 °C. The stillage was pretreated by enzymatic digestion prior to fast pyrolysis. Pyrolysis vapors were collected by fractional condensation to separate the heavy organic and aqueous phase liquids. The intention of this study was to assess the potential utilization of lignin-rich digested stillage as a fast pyrolysis feedstock. Heavy organic and aqueous phase pyrolysis liquids were obtained in yields ranging from 15.1 to 18.1?wt.% and 9.7 to 13.4?wt.% respectively. The rest of the feedstock material was converted to char (37.1 to 44.7?wt.%) and non-condensable gases (27.1 to 31.5?wt.%). Detailed liquid analysis indicated that the heavy organic phase fractions contain compounds arising from the degradation of lignin, residual microbial biomass and remaining polysaccharides. Fast pyrolysis adds 26.8?wt.% to the conversion of this otherwise recalcitrant feedstock material, thereby reducing waste generation and enhancing the value of second-generation bioethanol production.Prokofiev, V.Y., Banks, D.A., Lobanov, K.V., Selektor, S.L., Milichko, V.A., Akinfiev, N.N., Borovikov, A.A., Lüders, V., Chicherov, M.V., 2020. Exceptional concentrations of gold nanoparticles in 1,7 Ga fluid inclusions from the Kola superdeep borehole, northwest Russia. Scientific Reports 10, 1108. the drill core of the Kola super-deep borehole (SG-3, 12,262?m depth) gold-bearing rocks of Archaean age have been located at depths of 9,500 to 11,000?m. In veins, between 9,052 and 10,744?m, within this gold zone, quartz contains fluid inclusions with gold nanoparticles. There are 4 types of fluid inclusions (1) gas inclusions of dense CO2, (2) liquid-vapor two-phase aqueous inclusions, (3) three-phase inclusions with NaCl daughter crystals, and (4) CO2-aqueous inclusions. In all inclusion types, there are extremely high concentrations of gold. The highest gold concentrations were found in the type 3 and 4 fluid inclusions with an average concentration of c. 750 ppm and may be as high as 6,000 ppm. The presence of gold as nanoparticles in the solutions of these fluid inclusions was determined by optical and spectroscopic methods. We suggest that these fluids could be a precursor of “orogenic gold fluids” which, at the gold concentrations determined, would reduce the requirements for large volumes of metamorphic fluids to form orogenic ore deposits. Further, as nanoparticles, gold could be transported in larger amounts than in true solution.Qi, Y., Fu, P., Li, S., Ma, C., Liu, C., Volmer, D.A., 2020. Assessment of molecular diversity of lignin products by various ionization techniques and high-resolution mass spectrometry. Science of The Total Environment 713, 136573. is a highly complex, plant-derived natural biomass component, the analysis of which requires significant demands on the analytical platform. Fourier transform ion cyclotron mass spectrometry (FT-ICR MS) has been shown to be able to readily assess the complexity of lignin and lignin degradation products by assigning tens of thousands of compounds with elemental formulae. Nevertheless, many experimental and instrumental parameters introduce discrimination towards certain components, which limits the comprehensive MS analysis. As a result, a complete characterization of the lignome remains a challenge. The present study investigated a degraded lignin sample using FT-ICR MS and compared several atmospheric pressure ionization methods, e.g., electrospray ionization, atmospheric-pressure chemical ionization, and atmospheric-pressure photoionization. The results clearly show that the number of heteroatoms (e.g., N, S, P) in the sample greatly increases the chemical diversity of lignin, while at the same time also providing potentially useful biomarkers. We demonstrate here that FT-ICR MS was able to directly isolate isotopically pure single components from the ultra-complex mixture for subsequent structural analysis, without the time-consuming chromatographic separation. Capsule Various ionization techniques coupled to FT-ICR MS provide a powerful tool to assess the lignome coverage.Qiao, W., Puentes Jácome, L.A., Tang, X., Lomheim, L., Yang, M.I., Gaspard, S., Avanzi, I.R., Wu, J., Ye, S., Edwards, E.A., 2020. Microbial communities associated with sustained anaerobic reductive dechlorination of α-, β-, γ-, and δ-hexachlorocyclohexane isomers to monochlorobenzene and benzene. Environmental Science & Technology 54, 255-265. historical and worldwide use of pesticide formulations containing hexachlorocyclohexane (HCH) has led to widespread contamination. We derived four anaerobic enrichment cultures from HCH-contaminated soil capable of sustainably dechlorinating each of α-, β-, γ-, and δ-HCH isomers stoichiometrically to benzene and monochlorobenzene (MCB). For each isomer, the dechlorination rates, inferred from production rates of the dechlorinated products, MCB and benzene, increased progressively from <3 to ～12 μM/day over 2 years. The molar ratio of benzene to MCB produced was a function of the substrate isomer and ranged from β (0.77 ± 0.15), α (0.55 ± 0.09), γ (0.13 ± 0.02), to δ (0.06 ± 0.02) in accordance with pathway predictions based on prevalence of antiperiplanar geometry. Data from 16S rRNA gene amplicon sequencing and quantitative PCR revealed significant increases in the absolute abundances of Pelobacter and Dehalobacter, most notably in the α-HCH and δ-HCH cultures. Cultivation with a different HCH isomer resulted in distinct bacterial communities, but similar archaeal communities. This study provides the first direct comparison of shifts in anaerobic microbial communities induced by the dechlorination of distinct HCH isomers. It also uncovers candidate microorganisms responsible for the dechlorination of α-, β-, γ-, and δ-HCH, a key step toward better understanding and monitoring of natural attenuation processes and improving bioremediation technologies for HCH-contaminated sites.Qiu, Y., Wang, X.-L., Liu, X., Cao, J., Liu, Y.-F., Xi, B.-B., Gao, W.-L., 2020. In situ Raman spectroscopic quantification of CH4–CO2 mixture: application to fluid inclusions hosted in quartz veins from the Longmaxi Formation shales in Sichuan Basin, southwestern China. Petroleum Science 17, 23–35. re-evaluate the Raman spectroscopic quantification of the molar ratio and pressure for CH4–CO2 mixtures. Firstly, the Raman quantification factors of CH4 and CO2 increase with rising pressure at room temperature, indicating that Raman quantification of CH4/CO2 molar ratio can be applied to those fluid inclusions (FIs) with high internal pressure (i.e., >?15 MPa). Secondly, the v1(CH4) peak position shifts to lower wavenumber with increasing pressure at constant temperature, confirming that the v1(CH4) peak position can be used to calculate the fluid pressure. However, this method should be carefully calibrated before applying to FI analyses because large discrepancies exist among the reported v1(CH4)-P curves, especially in the high-pressure range. These calibrations are applied to CH4-rich FIs in quartz veins of the Silurian Longmaxi black shales in southern Sichuan Basin. The vapor phases of these FIs are mainly composed of CH4 and minor CO2, with CO2 molar fractions from 4.4% to 7.4%. The pressure of single-phase gas FI ranges from 103.65 to 128.35 MPa at room temperature, which is higher than previously reported. Thermodynamic calculations supported the presence of extremely high-pressure CH4-saturated fluid (218.03–256.82 MPa at 200 °C), which may be responsible for the expulsion of CH4 to adjacent reservoirs.Qiu, Z., Lu, B., Chen, Z., Zhang, R., Dong, D., Wang, H., Qiu, J., 2019. Discussion of the relationship between volcanic ash layers and organic enrichment of black shale: A case study of the Wufeng-Long-maxi gas shales in the Sichuan Basin. Acta Sedimentologica Sinica 37, 1296-1308. studies have shown that the deposition of volcanic ash from modern volcanic activity into seawater can improve marine surface productivity,promote the flourishing of plankton,and facilitate the formation and enrichment of organic matter. However,there are few studies on the relationship between volcanic ash deposition and organic matter enrichment in geological history,which has always been controversial. A large number of volcanic ash layers developed in the gas shales of the Wufeng-Longmaxi Formation during the Ordovician-Silurian transition in South China,providing a typical strata system for this research. Total organic carbon(TOC) content,paleo-productivity, and redox conditions of the shale horizons, including volcanic ash layers and no volcanic ash layers, were comparatively analyzed. The results show that the volcanic ash deposition during the Ordovician-Silurian transition had a relatively weak effect on marine productivity and did not significantly promote the accumulation of organic matter. The redox condition has a close relationship with TOC content,suggesting it could be the main controlling factor. The influence of volcanic activity on the sedimentary environment is a very complicated process. Therefore,in the future, comprehensive studies with higher resolution(such as centimeter-scale and millimeter-scale) should be carried out by using geological,geochemical,and other testing methods to finely analyze the impact of volcanic activity on the formation and enrichment of organic matter. Sediments related to volcanic activity are one of the research targets of unconventional petroleum sedimentology,and the determination of the relationship between them and organic enrichment in shale would have an important role in the exploration and development of unconventional petroleum,such as shale oil and gas.Qiu, Z., Zhang, Y., Zhao, X., He, Q., Chen, Z., Zhao, C., 2019. An experimental study on the optimization of drilling fluid in offshore gas hydrate formations. Natural Gas Industry 39, 104-109. Chinese. In the process of drilling offshore gas hydrate( "hydrate" for short) formations, the invasion of drilling fluid into formations may lead to hydrate decomposition, which will result in borehole instability. In order to solve these difficulties, this paper experimentally studied the decomposition law of methane hydrate under different decomposition modes. Then, the Peng–Robinson equation was introduced to calculate the change of methane gas mole number, and the experimental method for evaluating the inhibition of hydrate decomposition by drilling fluid was optimized. Finally, the effects of the kinetic inhibitor DY-1 and modified lecithin on the decomposition characteristics of hydrate were experimentally analyzed using this method, and the water-based drilling fluid suitable for gas hydrate formations was further optimized. And the following research results were obtained. First, the best way to evaluate the inhibition of drilling fluid on hydrate decomposition is to inject cold solution without relieving the pressure. Second, the DY-1 and modified lecithin can retard hydrate decomposition by adsorbing in hydrate surface to inhibit heat and mass transfer, so they can be used as hydrate decomposition inhibitors of drilling fluid. Third, the optimized drilling fluid system has good low-temperature rheological properties and shale inhibition and lubricity and can inhibit the formation and the decomposition of hydrates, so it can meet the basic requirements of drilling fluid technology for offshore gas hydrate formations. It is concluded that the research results can provide a drilling fluid technical support for the development of hydrates in China.Quarles, B., Barnes, J.W., Lissauer, J.J., Chambers, J., 2019. Obliquity evolution of the potentially habitable exoplanet Kepler-62f. Astrobiology 20, 73-90. in the axial tilt, or obliquity, of terrestrial planets can affect their climates and therefore their habitability. Kepler-62f is a 1.4 R⊕ planet orbiting within the habitable zone of its K2 dwarf host star. We perform N-body simulations that monitor the evolution of obliquity of Kepler-62f for 10-million-year timescales to explore the effects on model assumptions, such as the masses of the Kepler-62 planets and the possibility of outer bodies. Significant obliquity variation occurs when the rotational precession frequency overlaps with one or more of the secular orbital frequencies, but most variations are limited to ?10°. Moderate variations (～10–20°) can occur over a broader range of initial obliquities when the relative nodal longitude (ΔΩ) overlaps with the frequency and phase of a given secular mode. However, we find that adding outer gas giants on long-period orbits (～1000 days) can produce large (～60°) variations in obliquity if Kepler-62f has a very rapid (4?h) rotation period. The possibility of giant planets on long-period orbits impacts the climate and habitability of Kepler-62f through variations in the latitudinal surface flux, where large variations can occur on million year timescales.Quivelli, O., Marino, M., Rodrigues, T., Girone, A., Maiorano, P., Abrantes, F., Salgueiro, E., Bassinot, F., 2020. Surface and deep water variability in the Western Mediterranean (ODP Site 975) during insolation cycle 74: High-resolution calcareous plankton and molecular biomarker signals. Palaeogeography, Palaeoclimatology, Palaeoecology 542, 109583. reconstructed changes in productivity and surface/subsurface and deep-water dynamics in the Western Mediterranean through a multi-proxy study of Ocean Drilling Program Site 975 between late Marine Isotope Stage (MIS) 20 and early interglacial MIS 19. Our high-resolution study (down to ~200-year resolution) combines calcareous plankton assemblages (coccolithophores and foraminifera), biomarkers (C37-alkenones, n-alkanes, n-alcohols) and elemental proxies (total organic carbon, total nitrogen, calcium carbonate). Surface water conditions are derived (i) from high-resolution δ18O and δ13C records obtained from the planktonic foraminifer Globigerina bulloides, and (ii) from summer and winter, foraminifera-based sea surface temperature reconstructions (SSTJAS-foram, SSTJFM-foram) achieved through transfer function. The integration of the whole dataset makes it possible to identify in the Balearic Sea, and to accurately characterize for the first time, an Organic Rich Layer (ORL) during latest MIS 20-early MIS 19, close to i-cycle 74. Its presence is marked firstly by higher values of total nitrogen (TN) and an increase of total C37-alkenone and total organic carbon (TOC) preserved in the sediments. The multi-proxy approach reveals that the deglacial phase played a prominent role for ORL formation that was characterized by centennial scale phases. The alcohol preservation index (API) suggests that the shoaling of the circulation, which boosted marine productivity, started in the deglaciation and, in combination with freshening by Atlantic water inflow/riverine input and surface water buoyancy during sea level rising, culminated during the ORL event. At this time calcareous plankton proliferated on subsurface-surface waters, benefiting from ameliorating conditions, which promoted maximum marine productivity and higher organic matter preservation on the seafloor.Radwan, A.E., Abudeif, A.M., Attia, M.M., Elkhawaga, M.A., Abdelghany, W.K., Kasem, A.A., 2020. Geopressure evaluation using integrated basin modelling, well-logging and reservoir data analysis in the northern part of the Badri oil field, Gulf of Suez, Egypt. Journal of African Earth Sciences 162, 103743. evaluation of pore and fracture pressures represents the gist of well planning and execution in drilling operation and exploration, where accurate pore and fracture pressures modelling enables the oil and gas companies to drill targets safely. The scope of this paper is to evaluate pore and fracture pressures in the northern part of the Badri Field, in the Gulf of Suez, Egypt to determine the convenient pore pressure fracture gradient model (PPFG) and to define the pore pressure regime in the subsurface within the Zeit, South Gharib, Belayim and Kareem formations from the top downwards.The pore pressure and fracture gradient model has been assessed using integrated data that include: burial history, well logs (sonic, resistivity and density), offset wells drilling problems, and reservoir pressure. The Amoco overburden equation and Eaton's sonic and resistivity methods were used to estimate the overburden stress and the pore pressure values respectively, while fracture pressure was calculated using the Eaton method. Results show that the maximum pore pressures is in the South Gharib Formation and the lowest pore pressure is within the reservoir sections. Six abnormal pressure zones were detected, these includes four overpressure zones and two sub-normal pressure zones, where the maximum estimated pore pressure was up to 10.5 pound per gallon (ppg) equivalent gradient, which was recorded in the South Gharib Formation. While the minimum measured pore pressure value was recorded at 4.7 (ppg) in the Kareem sandstone reservoir. The fracture gradient ranged between 11.5 and 13.1 (ppg) equivalent density for both the Belayim (Hammam Faraun Member) and Kareem sandstone reservoirs.The main conclusions of this study are, 1) the pore pressure profile is normal, sub-normal and over-pressurized in the study area, 2) the integration of basin modelling, well-logging, drilling problems and direct measurements allow us to evaluate the geopressures in the subsurface horizons, 3) the use of low mud density while drilling into the depleted reservoir zones is the best solution for fluid losses mitigation, 4) the modified surface, intermediate and production casing seats is adequate for the future planned wells profile. 5) providing insights on downhole pressure behavior across stratigraphy in the area of study, to achieve optimum drilling mud designing and adequate casing seats as well as safe and successful operational planning.Rafter, P.A., Carriquiry, J.D., Herguera, J.-C., Hain, M.P., Solomon, E.A., Southon, J.R., 2019. Anomalous > 2000-year-old surface ocean radiocarbon age as evidence for deglacial geologic carbon release. Geophysical Research Letters 46, 13950-13960.: Geologic carbon from seafloor volcanism may influence late Pleistocene glacial terminations by increasing the global inventory of the greenhouse gas CO2. However, the evidence for geologic carbon flux associated with deep sea volcanism has been, so far, equivocal. Here, we construct a regional, glacial‐deglacial carbon budget of the volcanically active Gulf of California using microfossil 14C measurements and find results consistent with an increased addition of geologic carbon related to local seafloor volcanism during the deglaciation. Our estimates point to enhanced geologic carbon flux both before and during the last deglaciation that generally occur alongside carbonate preservation. This leads us to suggest that the carbon was added in the form of partially neutralized, 14C‐free bicarbonate associated with known Gulf sedimentary processes—a carbon source that would have a minimal effect on atmospheric CO2.Plain Language Summary: We account for the carbon entering and leaving the waters of the Gulf of California since the last ice age. Our results argue for increased supply of geologic carbon alongside enhanced volcanic activity after the last ice age. We argue that this delivery of geologic carbon to Gulf seawater was in the form of bicarbonate, not CO2, which would have a minimal impact on seawater acidity and is consistent with global sedimentary records.Rahi, P., Vaishampayan, P., 2020. Editorial: MALDI-TOF MS application in microbial ecology studies. Frontiers in Microbiology 10, 2954. doi: 10.3389/fmicb.2019. 02954. advancements in high-throughput sequencing, proteomics, metabolomics, and bioinformatics have revolutionized the microbial ecology research and immensely improved our understanding of the microbiome. Metagenomics and other cultivation-independent studies have shown that a diverse population of hundreds of millions of microorganisms habitat various ecosystems of the earth. The majority of these isolates have not yet been cultivated, and their metabolic functions remain unknown. Cultivation of microorganisms holds several essential advantages, which includes the prospection of isolated culture for their potential biotechnological applications. Though it is impossible to cultivate all the microbial community members, cultivation of majority of gut bacterial community members, including several novel taxa has been achieved by using multiple culture conditions approach (Lagier et al., 2016).Such studies involve simulation of culture conditions by mimicking the natural environment and high-throughput cultivation of microorganisms, leading to the development of a new approach known as “Culturomics” (Lagier et al., 2012). A rapid and reliable method for the identification of microorganisms from various ecosystems is critically required to meet the requirements of culturomics. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), based identification of microorganisms, appears the most suitable technique for this role. The ability to generate “portable” data to develop databases holds the key to its successful application in microbial ecology studies. In addition to high-throughput identification, MALDI-TOF MS has also been used for the analysis of microbial function or metabolism at the single organism and/or whole community level by the profiling of various biomolecules like proteins, sugar, and lipids (Clark et al., 2018; Weigt et al., 2018).The articles published under this Research Topic reported application of MALDI-TOF MS for the accurate and fast identification of microorganisms isolated from diverse environments including nosocomial settings (Florio et al.), biofilm habitats (Tuohy et al.), spacecraft and associated surfaces (Seuylemezian et al.), and cellular phones (Kurli et al.). In addition to this, a minireview highlighted the advantages and challenges associated with MALDI-TOF MS based microbial diagnosis and identification (Florio et al.), and an opinion article pointed to toward the collaborative efforts toward curated database especially for fungal community ecology (Lima et al.). In this editorial, we did a critical analysis of each article published under the Research Topic, and propose various solutions to improve the application of MALDI-TOF MS in microbial ecology studies.Recent Advances in MALDI-TOF MS in Microbial IdentificationMALDI-TOF MS is widely used in routine identification of microbial pathogens and has influenced clinical diagnostics and is replacing existing identification methods, including both biochemical and 16S rRNA gene sequencing. The rapid identification of microorganisms causing nosocomial infections, in addition to the knowledge of the antibiotic resistance patterns is highly advantageous especially in terms of morbidity, mortality, and health costs savings (Florio et al.). New perspectives are being explored for MALDI-TOF MS in microbial identification, such as analyzing direct positive blood cultures for identification of pathogens, sub-species and strain typing, detection of drug resistance determinants, and generating specialized metabolite MS profiles to assess bacterial functional traits (Florio et al.; Clark et al., 2018; Ovia?o and Bou, 2018). Most of these applications of MALDI-TOF MS are in the preliminary stage of development and require more standardization to provide reliable solutions. The applications of MALDI-TOF MS in the rapid identification of bacteria from positive blood cultures, which allow identification of infection-causing bacteria instantly (Florio et al.) The impact of sample processing methods on the observed variability incorrect identification rates was discussed in this mini-review, but authors missed to give any recommendations to improve the identifications from positive blood culture. Recently, a small modification in the sample processing allowed identification of Brucella infection directly from positive blood culture with MALDI-TOF MS (Bruker) within 2 h, and saved almost 48 h from positive blood culture to correct identification of pathogen (Guo et al., 2019). The development of MALDI-TOF MS based methods for the assessment of antimicrobial resistance in both bacteria and fungi are also in the early stage of development (Florio et al.) More focused studies on the development and validation of new methods will be necessary before MALDI-TOF MS can be used in routine assays for the diagnosis of antimicrobial resistance.Recently, a MALDI-TOF mass spectrometry data acquisition and bioinformatics pipeline (IDBac) is designed by integrating the data from both intact protein and specialized metabolite spectra directly from bacterial cells grown on agar (Clark et al., 2018). This coupling of MALDI-TOF mass spectrometry protein and specialized metabolite analyses resulted in establishing an instant connection between microbial phylogenetic identities with potential environmental functions. Such innovations allow utilization of full capabilities offered by MALDI-TOF MS for the analyses of microbial metabolites and the identification of microorganisms (Clark et al., 2018). MALDI-TOF MS is also finding applications in removing the redundancy, in big microbial discovery and bioprospection projects. MALDI-TOF MS and the bioinformatics pipeline IDBac offers a cost-effective way to rapidly de-replicate the microbial collection based on both the bacterial identity and the natural product producing capacity of colonies in high-throughput (Costa et al., 2019).MALDI-TOF MS based identification becoming a must for the large-scale culturomics experiments, as it is a fast and cost-effective method to filter out multiple conspecific strains or genetically identical clones (Dumolin et al., 2019). Though, the limited database and bias of commercial databases toward microbes of clinical or food safety relevance restrict the application of MALDI-TOF MS. Methods based on similarity measures combined with the clustering of MALDI-TOF mass spectra have been developed to uncouple dereplication from database based identification. Till recently, the identification of identical strains was done by visual interpretation of dendrograms or by using a distance cutoff value (Strejcek et al.). Recently, an algorithm (SPeDE) has been introduced, which enables the rapid analysis and dereplication of isolates using comparison of MALDI-TOF MS profiles (Dumolin et al., 2019). This approach identifies unique spectral features between pairs of spectra and clusters them into operational isolation units (OIUs).MALDI-TOF MS based clustering has also been used to reveal a potential clonal route of transmission of Enterobacter spp. preferentially between general surgery and geriatric wards, which were different from strains of other wards (Florio et al.). This study represents an important source of information about the spreading of Enterobacter, which is an emergent pathogen for its ability to acquire determinants of antimicrobial resistance and role of MALDI-TOF MS in microbiological surveillance in nosocomial setting (Florio et al.). In addition to microorganisms of clinical origin, MALDI-TOF MS offered a high-resolution approach to differentiate environmental isolates of the genus Deinococcus at the subpopulation level, isolated from a freshwater system from other environmental niches (Tuohy et al.). Though the sample size was small (19 isolates) in the study, still it was able to demonstrate the capability of MALDI-TOF MS as a reliable tool to differentiate Deinococcus aquaticus isolates that originate from specific niches (Tuohy et al.). Use of MALDI-TOF MS data for efficient dereplication of recurrent bacterial isolates for downstream analyses was suggested with minimal loss of unique organisms (Strejcek et al.).Challenges in MALDI-TOF MS in Microbial IdentificationSeveral studies concluded that low reliable identification of microbes from non-clinical ecosystems such as soil, water, spacecraft assembly cleanrooms, is due to the heavy dominance of MS profiles from clinical isolates in the database (Rahi et al., 2016; Seuylemezian et al.; Strejcek et al.). MALDI-TOF MS based microbial identification platforms allow creating and including a custom, user-specific, and transferable database (Rau et al., 2016; Seuylemezian et al.). The development of a custom database of MALDI-TOF MS profiles of bacterial isolates obtained from spacecraft and associated cleanroom environments has led to the successful identification of 454 bacterial isolates in concurrence with their 16S rRNA gene sequence-based classifications (Seuylemezian et al.). In this study, authors also observed that MALDI-TOF MS could resolve strain-level variations, identified potential novel species and distinguished between members of taxonomic groups, which is not possible using conventional 16S rRNA gene sequencing (Seuylemezian et al.). The results of both 16S rRNA gene sequence-based EzBioCloud Identify service (REF/site) and the MALDI Biotyper database corroborated well in identifying the bacterial strains up to the genus-level, except four unreliably identification by the MALDI Biotyper method (Strejcek et al.). The study also highlighted that only ~35% species-level identifications by MALDI Biotyper could coincide with those identified by 16S rRNA gene sequencing analysis, indicating weak species-level identification by MALDI-TOF MS (Strejcek et al.).Insufficient coverage of bacterial species in the databases has been suggested as the primary reason for these discrepancies (Strejcek et al.). Lack of public repository to submit the new spectral references generated by researchers further worsen this problem (Seuylemezian et al.; Strejcek et al.). The problem worsens in the absence of clear standards and tools to verify the accuracy of the reference profiles. However, the attempts are being made to define a universal MALDI spectral database (Rahi et al., 2016). Simultaneous, efforts have been made to develop user-to-user internet platforms like MALDI-UP specifically designed to facilitate the exchange of in-house MALDI spectral database entries (Rau et al., 2016). In addition to this, researchers might be sharing the spectral database formally and informally, and such exercise will help to develop a consensus on the universal codes for the high-quality spectral entries.All the database repository efforts and online user-to-user platforms have hidden challenges of erroneous database entries, the requirement of continuous curation and validation. These challenges could be the bottleneck to spectral data sharing and repository. The deposition of microbial strains with Microbial Biological Resource Centers (mBRCs) to make them accessible to the research community for verifications and validations of the MALDI-TOF MS spectral database could be a solution to this problem. Although the biodiversity laws of several countries do not allow free movement of microbial cultures, hindering such international efforts (Soltanighias et al., 2018). Blind classification of the microbial strains and inter-lab comparisons could help validate the newly generated spectral profiles.The availability of freely accessible, well-curated MALDI-TOF MS spectra database that allows query search using a web-based interface, comparable to BLAST search on the NCBI GenBank website and databases, could help researchers to identify microbial isolates, without adding spectral profiles into their in-house database (Normand et al., 2017). In a collaborative effort, researchers from five laboratories in France and Belgium developed a free access software to scan a fungal database, which includes spectra of strains belonging to 938 species and 246 genera (Normand et al., 2017). Although at present this tool is limited to the identification of fungi, similar tools can be developed for other microbial groups, and here the mBRCs, need to play a significant proactive role as they have extensive collections of well-curated microbial strains.The quality and accuracy of MALDI-TOF MS spectra can be influenced by the sample preparation methods, matrix components, and type of material analyzed (Lima et al.). During the identification of an extensive collection of microorganisms isolated from cellular phone surfaces, it was observed that quality filtering of MALDI-TOF MS spectrum, improving sample processing methods and enriching the spectral database lead to better and highly reliable results for microbial identifications by MALDI-TOF MS (Kurli et al.). In this study, genus-level identity was achieved for nearly 80% isolates (Kurli et al.). Improvements in the quality of MALDI-TOF MS spectrum (i.e., peak number and intensity) can reduce the number of no reliable identification and also lower the number of erroneous identification (Kurli et al.). If we could find feasible solutions for the challenges associated with MALDI-TOF MS, this technique has the potential to become a “golden standard” for the identification of diverse groups of bacteria and fungi (Lima et al.).The development of newer algorithms and sample processing methods will improve the applications of MALDI-TOF MS and increase its relevance in microbial ecology studies. Further standardization and ease of accessibility of the mass spectral libraries from variety of environmental sources, and not just clinical origin, will make it the method of choice for microbial ecology studies. Application of the MALDI-TOF MS in large-scale screening and identification studies will increase in the near future, due to the advances in the automation and de-replication, and lead to the discovery of novel microbial species.ReferencesClark, C. M., Costa, M. S., Sanchez, L. M., and Murphy, B. T. (2018). Coupling MALDI-TOF mass spectrometry protein and specialized metabolite analyses to rapidly discriminate bacterial function. Proc. Natl. Acad. Sci. U.S.A. 115, 4981–4986. doi: 10.1073/pnas.1801247115Costa, M. S., Clark, C. M., ?marsdóttir, S., Sanchez, L. M., and Murphy, B. T. (2019). Minimizing taxonomic and natural product redundancy in microbial libraries using MALDI-TOF MS and the bioinformatics pipeline IDBac. J. Nat. Prod. 82, 2167–2173. doi: 10.1021/acs.jnatprod.9b00168Dumolin, C., Aerts, M., Verheyde, B., Schellaert, S., Vandamme, T., Van der Jeugt, F., et al. (2019). Introducing SPeDE: high-throughput dereplication and accurate determination of microbial diversity from matrix-assisted laser desorption-ionization time of flight mass spectrometry data. mSystems 4:e00437–19. doi: 10.1128/mSystems.00437-19Guo, J., Lai, W., Li, B., Tang, L., Wu, Y., Luo, Y., et al. (2019). Rapid identification of Brucella sepsis/osteomyelitis in a 6-year old febrile patient with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry directly from positive blood culture: a case report. BMC Infect. Dis. 19:240. doi: 10.1186/s12879-019-3864-zLagier, J.-C., Khelaifia, S., Alou, M. T., Ndongo, S., Dione, N., Hugon, P., et al. (2016). Culture of previously uncultured members of the human gut microbiota by culturomics. Nat. Microbiol. 1:16203. doi: 10.1038/nmicrobiol.2016.203Lagier, J. C., Armougom, F., Million, M., Hugon, P., Pagnier, I., Robert, C., et al. (2012). Microbial culturomics: paradigm shift in the human gut microbiome study. Clin. Microbiol. Infect. 18, 1185–1193. doi: 10.1111/1469-0691.12023Normand, A. C., Becker, P., Gabriel, F., Cassagne, C., Accoceberry, I., Gari-Toussaint, M., et al. (2017). Validation of a new web application for identification of fungi by use of matrix-assisted laser desorption ionization-time of flight mass spectrometry. J. Clin. Microbiol. 55, 2661–2670. doi: 10.1128/JCM.00263-17Ovia?o, M., and Bou, G. (2018). Matrix-assisted laser desorption ionization–time of flight mass spectrometry for the rapid detection of antimicrobial resistance mechanisms and beyond. Clin. Microbiol. Rev. 32:e00037–e00018. doi: 10.1128/CMR.00037-18Rahi, P., Prakash, O., and Shouche, Y. S. (2016). Matrix-assisted laser desorption/ionization time-of-flight mass-spectrometry (MALDI-TOF MS) based microbial identifications: challenges and scopes for microbial ecologists. Front. Microbiol. 7:1359. doi: 10.3389/fmicb.2016.01359Rau, J., Eisenberg, T., Wind, C., Lasch, P., and Sting, R. (2016). MALDI-UP – An internet platform for the exchange of MALDI-TOF mass spectra. Asp. Food Control Anim. Heal. J. 1, 1–17. Available online at: , T., Vaid, R. K., and Rahi, P. (2018). “Agricultural Microbial Genetic Resources: Application and Preservation at Microbial Resource Centers,” in Microbial Resource Conservation, eds S. K. Sharma and A. Verma (Cham: Springer), 141–173. doi: 10.1007/978-3-319-96971-8_5Weigt, D., Sammour, D. A., Ulrich, T., Munteanu, B., and Hopf, C. (2018). Automated analysis of lipid drug-response markers by combined fast and high-resolution whole cell MALDI mass spectrometry biotyping. Sci. Rep. 8:1120. doi: 10.1038/s41598-018-29677-zRamírez, D., Vega-Alvarado, L., Taboada, B., Estradas-Romero, A., Soto, L., Juárez, K., 2020. Bacterial diversity in surface sediments from the continental shelf and slope of the North West Gulf of Mexico and the presence of hydrocarbon degrading bacteria. Marine Pollution Bulletin 150, 110590. play an important role in ecological processes in oil contaminated marine sediments. In this work, bacterial diversity studies with surface sediment samples from the NW Gulf of Mexico were performed, two from continental shelf and two from upper slope. The bacterial communities seem significantly influenced by depth, distance from the shoreline, temperature, dissolved oxygen and aluminum. The most abundant Phylum was Proteobacteria, Class Gammaproteobacteria. However, Class Deltaproteobacteria, Order Desulfuromonadales predominated in continental shelf and Order Alteromonadales (Gammaproteobacteria) prevailed in the upper slope sediments. Many potential hydrocarbon degrading bacterial genera were identified, 71 of the assigned genera were associated to hydrocarbon degradation processes. The genera Desulfobulbus and Haliea were confined to continental inner-shelf, while Shewanella and Fusibacter were mostly detected in deeper sediments. The occurrence and abundance of putative hydrocarbon degrading bacteria in this area, could be indicative of an impacted zone caused by the presence hydrocarbons in the environment.Rams?e, A., van Heekeren, V., Ponce, P., Fischer, R., Barnes, I., Speller, C., Collins, M.J., 2020. DeamiDATE 1.0: Site-specific deamidation as a tool to assess authenticity of members of ancient proteomes. Journal of Archaeological Science 115, 105080. is a potential problem in the study of ancient proteins, either from prior handling of the sample, laboratory consumables, or cross-sample carryover from mass spectrometers. Recently, deamidation of glutamine has been proposed as a measure for assessing the degradation of ancient proteins. Here, we present deamiDATE 1.0, a method for the authentication of ancient proteins using measure of site-specific deamidation rates. We test this approach on shotgun proteomic data derived from bone collagen from modern, archaeological and extinct taxa. We further demonstrate how this method may be used to differentiate between modern contaminants and authentic ancient proteins using a case study from Neolithic dental calculus.Ratheesh Kumar, C.S., Renjith, K.R., Joseph, M.M., Salas, P.M., Resmi, P., Chandramohanakumar, N., 2019. Inventory of aliphatic hydrocarbons in a tropical mangrove estuary: a biomarker approach. Environmental Forensics 20, 370-384. hydrocarbons in the sediments of the estuarine mangrove forests of Cochin region, Southwest coast of India were characterized to assess the sources of organic matter (OM) and to validate the effectiveness of the various geochemical indices to identify multiple OM sources and the complex geochemistry of these tropical coastal environments. The total concentration of the n-alkanes varied from 606.39 to 826.25??g/g [dry weight (dw)] in mangrove sediments, to values between 230.10 and 287.67??g/g in estuarine sediments. The n-alkane distribution in the study region indicated a strong odd over even predominance in both mangrove and estuarine sediments. Assessment using terrestrial OM indices such as Carbon Preference Index (CPI), Terrigenous Aquatic Ratio (TAR), and Terrestrial Marine Discriminant (TMD) suggested that a large fraction of OM in the mangrove sediments was derived from mangrove plant litter and a better preservation of mangrove OM in the sedimentary environment has occurred. These findings are supported by the higher content of total lipid, tannin, and lignin, as well as by the depleted δ13C values. Low ratios of CPI, TAR, and TMD at estuarine sites E2 and E3 indicated a mixed origin of OM. Natural or biogenic indices such as natural n-alkanes ratio (NAR), Σn-alkanes/n-C16, n-C29/n-C17, and LMW/HMW revealed that all the mangrove stations and the estuarine station E1 received OM from natural or biogenic sources, whereas a significant anthropogenic input was noticed for estuarine stations E2 and E3. Indices like Pr/Ph, Pr/n-C17, Ph/n-C18 further confirmed the mixed nature of OM accumulated under the anoxic environment.Reid, L.M., Payne, J.L., García-Bellido, D.C., Jago, J.B., 2020. The Ediacara Member, South Australia: Lithofacies and palaeoenvironments of the Ediacara biota. Gondwana Research 80, 321-334. Ediacara Member of the Rawnsley Quartzite in the Flinders Ranges (South Australia) has undergone considerable investigation due to its placement within the package of terminal Ediacaran sediments in the region and as the host sediments of the Ediacara biota fossils. A focus on palaeoenvironment reconstruction and taphonomy has seen a succession of lithofacies models presented. These have evolved with the expansion of recognised Ediacara biota localities and prevailing palaeontological methodologies. Much of the recent descriptive lithofacies work has focused on the Nilpena fossil site in the west of the Flinders Ranges. This location is particularly fossil-rich but does not represent a “typical” section through the Ediacara Member. The Ediacara Member elsewhere in the region contains up to six parasequences with total thicknesses varying from ten to 260?m. With the exclusion of the Ikara-Chace Range region, the majority of studied locations external to Nilpena do not show clear evidence for significant (canyon-scale), intra-member erosional features. In this study we review existing facies models for the Ediacara Member and compile a “best-fit” revised facies model by incorporating the modern facies interpretations (largely based at Nilpena) and previous basin-wide observations, models and stratigraphic sections. The revised model is assessed against a series of newly measured stratigraphic sections from across the basin. We propose the division of the wave-base facies into two facies, representative of the upper and lower storm wave-base environments respectively and the re-inclusion of a facies representative of a shoreface palaeoenvironment. Additional characters and identifiers for the facies have been incorporated to aid field identification, as the ability to identify facies of fossil-bearing isolated hand-specimens can allow fossils found on scree slopes to be traced back to source beds. Likewise, palaeoenvironmental interpretations are critical to the reconstruction of Ediacara biota habitat and preservational environments.Rellegadla, S., Jain, S., Agrawal, A., 2020. Oil reservoir simulating bioreactors: tools for understanding petroleum microbiology. Applied Microbiology and Biotechnology 104, 1035-1053. aspects of the oil fields in terms of microbial activity (souring, biocorrosion, etc.) and oil production (polymer flooding, etc.) have been evaluated through a variety of experiments. The primary step to study these properties in the laboratory requires the construction and operation of up-flow oil reservoir simulating bioreactors (ORSBs) in real time. Souring by reduction of sulfate to sulfide is a major contributor in enhancing corrosion of metal infrastructure used for oil production and processing. Whether the injection of biocides prevents or remediates reservoir souring can be addressed by flooding up-flow ORSBs. The potential of biopolymers/biosurfactants produced by different microbial strains have also been investigated for the role in maintaining additional oil recovery using ORSB. Additionally, key issues of polymer behavior during flooding of reservoirs could be understood during laboratory studies by monitoring the in situ porous medium rheology. Besides, the change in various ORSB parameters helps in adjudging the effect of different biosurfactants/biopolymers in enhancing oil recovery. Parameters such as permeability reduction, adsorption, interaction with porous matrix, and formation damage can be evaluated using ORSB. The analysis of earlier studies indicated that running bioreactors for longer duration of time can help in drawing conclusion with sharpness and less ambiguity. The current review discusses the construction and application of various types of ORSBs including the experimental studies employing ORSBs.Remizovschi, A., Carpa, R., Forray, F.L., Chiriac, C., Roba, C.-A., Beldean-Galea, S., Andrei, A.-?., Szekeres, E., Baricz, A., Lupan, I., Knut, R., Coman, C., 2020. Mud volcanoes and the presence of PAHs. Scientific Reports 10, 1253. mud volcano (MV) is a naturally hydrocarbon-spiked environment, as indicated by the presence of various quantities of PAHs and aromatic isotopic shifts in its sediments. Recurrent expulsion of various hydrocarbons consolidates the growth of hydrocarbonoclastic bacterial communities in the areas around MVs. In addition to the widely-known availability of biologically malleable alkanes, MVs can represent hotbeds of polyaromatic hydrocarbons (PAHs), as well - an aspect that has not been previously explored. This study measured the availability of highly recalcitrant PAHs and the isotopic signature of MV sediments both by GC-MS and δ13C analyses. Subsequently, this study highlighted both the occurrence and distribution of putative PAH-degrading bacterial OTUs using a metabarcoding technique. The putative hydrocarbonoclastic taxa incidence are the following: Enterobacteriaceae (31.5%), Methylobacteriaceae (19.9%), Bradyrhizobiaceae (16.9%), Oxalobacteraceae (10.2%), Comamonadaceae (7.6%) and Sphingomonadaceae (5.5%). Cumulatively, the results of this study indicate that MVs represent polyaromatic hydrocarbonoclastic hotbeds, as defined by both natural PAH input and high incidence of putative PAH-degrading bacterial OTUs.Reymond, C., Dubuis, A., Le Masle, A., Colas, C., Chahen, L., Destandau, E., Charon, N., 2020. Characterization of liquid–liquid extraction fractions from lignocellulosic biomass by high performance liquid chromatography hyphenated to tandem high-resolution mass spectrometry. Journal of Chromatography A 1610, 460569. conversion of lignocellulosic biomass is a major challenge in the field of renewable energies and bio-based chemicals. The diversity of biomasses and processes leads to complex products having a wide range of polarities and molecular weights. Nowadays, the molecular description of these oxygenated matrices is still largely incomplete and new analytical strategies are required to have a better understanding of biomass products properties. The present study proposes a reliable protocol based on successive liquid–liquid extractions prior to high performance liquid chromatography hyphenated to high-resolution tandem mass spectrometry (HPLC/MSn) using a linear ion trap-Fourier transform ion cyclotron resonance mass spectrometer (LTQ/FT-ICR). The protocol allowed to fractionate an industrial sample coming from the sulfuric acid-based pretreatment of a wheat straw into four key chemical families: carbohydrates, organic acids, phenols and neutral compounds. Each fraction was separately analyzed, which limited matrix effects during mass spectrometry ionization step. Electrospray and atmospheric pressure chemical ionization sources were used in both positive and negative modes in order to ionize and detect a maximum of compounds. Thanks to HPLC/MSn, structures of heavy lignin-carbohydrate complexes (LCC) were elucidated (up to 600?g/mol) as well as carbohydrate oligomers having acid functionalities. Mono, di, tri and tetra-aromatic compounds coming from lignin were also detected. The results reported in this paper demonstrate the complexity of pretreated biomass samples and propose an analytical approach from sample simplification to data treatment in order to describe the biomass composition.Rezende, E.L., Bacigalupe, L.D., Nespolo, R.F., Bozinovic, F., 2020. Shrinking dinosaurs and the evolution of endothermy in birds. Science Advances 6, eaaw4486. evolution of endothermy represents a major transition in vertebrate history, yet how and why endothermy evolved in birds and mammals remains controversial. Here, we combine a heat transfer model with theropod body size data to reconstruct the evolution of metabolic rates along the bird stem lineage. Results suggest that a reduction in size constitutes the path of least resistance for endothermy to evolve, maximizing thermal niche expansion while obviating the costs of elevated energy requirements. In this scenario, metabolism would have increased with the miniaturization observed in the Early-Middle Jurassic (~180 to 170 million years ago), resulting in a gradient of metabolic levels in the theropod phylogeny. Whereas basal theropods would exhibit lower metabolic rates, more recent nonavian lineages were likely decent thermoregulators with elevated metabolism. These analyses provide a tentative temporal sequence of the key evolutionary transitions that resulted in the emergence of small, endothermic, feathered flying dinosaurs.Richardson, S.D., Kimura, S.Y., 2020. Water analysis: Emerging contaminants and current issues. Analytical Chemistry 92, 473-505. biennial review covers developments in water analysis for emerging environmental contaminants over the period of October 2017–October 2019. Analytical Chemistry’s policy is to limit reviews to a maximum of ～250 significant references and to mainly focus on new trends. Therefore, only a small fraction of the quality research publications is discussed. The previous Water Analysis review (with Thomas Ternes) was published in 2018.(1) This year, Susana Kimura joined me to cover the section on Pharmaceuticals and Hormones. We welcome any comments you have on this Review. Numerous abstracts were consulted before choosing the best representative ones to present here. Abstract searches were carried out using Web of Science, and in many cases, full articles were obtained. A table of acronyms is provided (Table 1) as a quick reference to the acronyms of analytical techniques and other terms discussed in this Review. Table 2 provides some useful Web sites.Rizal, Y., Westaway, K.E., Zaim, Y., van den Bergh, G.D., Bettis, E.A., Morwood, M.J., Huffman, O.F., Grün, R., Joannes-Boyau, R., Bailey, R.M., Sidarto, Westaway, M.C., Kurniawan, I., Moore, M.W., Storey, M., Aziz, F., Suminto, Zhao, J.-x., Aswan, Sipola, M.E., Larick, R., Zonneveld, J.-P., Scott, R., Putt, S., Ciochon, R.L., 2020. Last appearance of Homo erectus at Ngandong, Java, 117,000–108,000?years ago. Nature 577, 381-385. erectus is the founding early hominin species of Island Southeast Asia, and reached Java (Indonesia) more than 1.5 million years ago. Twelve H. erectus calvaria (skull caps) and two tibiae (lower leg bones) were discovered from a bone bed located about 20 m above the Solo River at Ngandong (Central Java) between 1931 and 1933, and are of the youngest, most-advanced form of H. erectus. Despite the importance of the Ngandong fossils, the relationship between the fossils, terrace fill and ages have been heavily debated. Here, to resolve the age of the Ngandong evidence, we use Bayesian modelling of 52 radiometric age estimates to establish—to our knowledge—the first robust chronology at regional, valley and local scales. We used uranium-series dating of speleothems to constrain regional landscape evolution; luminescence, 40argon/39argon (40Ar/39Ar) and uranium-series dating to constrain the sequence of terrace evolution; and applied uranium-series and uranium series–electron-spin resonance (US–ESR) dating to non-human fossils to directly date our re-excavation of Ngandong. We show that at least by 500 thousand years ago (ka) the Solo River was diverted into the Kendeng Hills, and that it formed the Solo terrace sequence between 316 and 31 ka and the Ngandong terrace between about 140 and 92 ka. Non-human fossils recovered during the re-excavation of Ngandong date to between 109 and 106 ka (uranium-series minimum) and 134 and 118 ka (US–ESR), with modelled ages of 117 to 108 thousand years (kyr) for the H. erectus bone bed, which accumulated during flood conditions. These results negate the extreme ages that have been proposed for the site and solidify Ngandong as the last known occurrence of this long-lived species.Robinson, K.J., Fecteau, K.M., Gould, I.R., Hartnett, H.E., Williams, L.B., Shock, E.L., 2020. Metastable equilibrium of substitution reactions among oxygen- and nitrogen-bearing organic compounds at hydrothermal conditions. Geochimica et Cosmochimica Acta 272, 93-104. abundances of organic compounds can reveal information about the environments in which they formed. Since organic compounds can be mobilized and released from geologic and planetary settings, they have the potential to provide insights into environments that are difficult to observe directly. To advance our understanding of these environments, this study identifies organic reactions that approach metastable equilibrium in experiments, so that future studies can predict geochemical conditions in remote settings (e.g., deep Earth, extraterrestrial bodies) by monitoring reaction ratios of compounds involved in similar organic reactions. At high temperatures organic redox reactions can equilibrate, which allows comparisons with thermodynamic properties to yield estimates of reaction conditions. However, redox reactions may equilibrate too slowly to be applicable to lower temperature systems. To explore metastable equilibria at lower temperatures, we studied substitution reactions that tend to be faster than redox reactions. In this study, we demonstrate that oxygen- and nitrogen-bearing organic compounds at hydrothermal conditions undergo a series of simultaneous substitution reactions that rapidly approach steady-state ratios indicative of metastable equilibrium. Four sets of aqueous experiments were performed at 250?°C and 40?bar, each beginning with a single organic reactant: benzyl alcohol, benzylamine, dibenzylamine, or tribenzylamine. All reactant solutions were prepared with identical bulk elemental compositions by adjusting the concentrations of the starting organic compounds and adding ammonia as needed. After 2?h at hydrothermal reaction conditions, all of the model compounds were detectable in all four sets of experiments, evidence for reversibility of reactions among the compounds. After 72?h, reaction ratios between the model compounds converged in all four sets of experiments, consistent with approaches toward metastable equilibrium. Reaction ratios for ether and aldehyde formation reactions were also observed to group within a relatively small range, but without a clear convergence pattern, suggesting other non-redox reactions may approach metastable equilibrium. The approach to metastable equilibrium among the initial organic reactants could be observed and quantified even in the presence of competing redox reactions whose mechanisms are less understood, including dibenzylimine and toluene formation, which did not appear to reach steady-states. These findings identify classes of organic compounds and reactions that can reflect the conditions at which they last equilibrated and should be targeted for analysis in natural systems.Roebuck, J.A., Seidel, M., Dittmar, T., Jaffé, R., 2020. Controls of land use and the river continuum concept on dissolved organic matter composition in an anthropogenically disturbed subtropical watershed. Environmental Science & Technology 54, 195-206. 250 Tg of dissolved organic carbon are annually transported from inland waters to coastal systems making rivers a critical link between terrestrial and ocean carbon pools. During transport through fluvial systems, various biogeochemical processes selectively remove or transform labile material, effectively altering the composition of dissolved organic matter (DOM) exported to the ocean. The river continuum concept (RCC) has been historically used as a model to predict the fate and quality of organic matter along a river continuum. However, the conversion of natural landscapes for urban and agricultural practices can also alter the sources and quality of DOM exported from fluvial systems, and the RCC may be significantly limited in predicting DOM quality in anthropogenically impacted watersheds. Here, we studied DOM dynamics in the Altamaha River watershed in Georgia, USA, a fluvial system where headwater streams are highly impacted by anthropogenic activities. The primary goal of this study was to quantitatively assess the importance of both the RCC and land use as environmental drivers controlling DOM composition. Land use was a stronger predictor of spatial variation (～50%) in DOM composition defined by both excitation–emission matrix–parallel factor analysis (EEM–PARAFAC) and ultrahigh-resolution mass spectrometry. This is compared to an 8% explained variability that can be attributed to the RCC. This study highlights the importance of incorporating land use among other controls into the RCC to better predict the fate and quality of DOM exported from terrestrial to coastal systems.Rontani, J.-F., Belt, S.T., 2020. Photo- and autoxidation of unsaturated algal lipids in the marine environment: An overview of processes, their potential tracers, and limitations. Organic Geochemistry 139, 103941. paper provides an overview of results obtained in the course of recent studies dealing with abiotic degradation of algal lipids in the marine realm. In the first part, the photooxidation of the main lipid components (chlorophyll phytyl chain, carotenoids, Δ5-sterols, unsaturated fatty acids, alkenones and unsaturated alkenes) in senescent phytoplanktonic cells is examined. Type II photosensitized oxidation processes (i.e. involving singlet oxygen) play a key role in the photooxidation of these compounds. The second part of the paper describes free radical oxidation of the main lipids in senescent phytoplanktonic cells. These processes, which are believed to be induced by homolytic cleavage of photochemically produced hydroperoxides, involve the direct reaction of molecular oxygen in its triplet ground state with organic compounds under relatively mild conditions. Particular attention is given to the characterisation of pathway-specific tracers of the individual abiotic reactions described. Some of these compounds appear to have the potential to provide qualitative or semi-quantitative information about photooxidation, autoxidation, or the total abiotic degradation state of individual or groups of organisms. On the other hand, some other primary oxidation products are likely too susceptible to further degradation to permit reliable quantitative estimates, but can, nonetheless, provide a qualitative indication of photooxidation and autoxidation.Root-Gutteridge, H., Ratcliffe, V.F., Korzeniowska, A.T., Reby, D., 2019. Dogs perceive and spontaneously normalize formant-related speaker and vowel differences in human speech sounds. Biology Letters 15, 20190555. animals have been shown to recognize basic phonemic information from human speech sounds and to recognize familiar speakers from their voices. However, whether animals can spontaneously identify words across unfamiliar speakers (speaker normalization) or spontaneously discriminate between unfamiliar speakers across words remains to be investigated. Here, we assessed these abilities in domestic dogs using the habituation–dishabituation paradigm. We found that while dogs habituated to the presentation of a series of different short words from the same unfamiliar speaker, they significantly dishabituated to the presentation of a novel word from a new speaker of the same gender. This suggests that dogs spontaneously categorized the initial speaker across different words. Conversely, dogs who habituated to the same short word produced by different speakers of the same gender significantly dishabituated to a novel word, suggesting that they had spontaneously categorized the word across different speakers. Our results indicate that the ability to spontaneously recognize both the same phonemes across different speakers, and cues to identity across speech utterances from unfamiliar speakers, is present in domestic dogs and thus not a uniquely human trait.Ruebsam, W., Reolid, M., Schwark, L., 2020. δ13C of terrestrial vegetation records Toarcian CO2 and climate gradients. Scientific Reports 10, 117. Earth’s history, variations in atmospheric CO2 concentration modulated climate. Understanding changes in atmospheric carbon cycle is therefore pivotal in predicting consequences of recent global warming. Here, we report stable carbon isotopes (δ13C) of molecular land plant fossils complemented by bulk organic and inorganic carbon fractions for early Toarcian (Early Jurassic) sediments that coincided with global warming and a carbon cycle perturbation. The carbon cycle perturbation is expressed by a negative excursion in the δ13C records established for the different substrates. Based on differences in the magnitude of the carbon isotope excursion recorded in land plants and marine substrates we infer that the early Toarcian warming was paralleled by an increase in atmospheric CO2 levels from ~500 ppmv to ~1000 ppmv. Our data suggest that rising atmospheric CO2 levels resulted from the injection of 12C-enriched methane and its subsequent oxidation to CO2. Based on the cyclic nature of the CIE we concluded that methane was released from climate sensitive reservoirs, in particular permafrost areas. Moderate volcanic CO2 emissions led to a destabilization of the labile permafrost carbon pool triggering the onset of Toarcian climate change only. The main carbon cycle perturbation then subsequently was driven by a self-sustained demise of a carbon-rich cryosphere progressing from mid to high latitudes as reflected by latitudinal climate gradients recorded in land plant carbon isotopes.Rugenstein, J.K.C., 2020. What goes down must come up. Nature Geoscience 13, 5-7. cycling of carbonate and organic carbon in the mantle may link the Great Oxidation Event and the subsequent increase in carbon isotope values, according to a model that links the Earth’s surface and interior.Approximately 2.5 billion years ago, the concentration of oxygen in the atmosphere rose rapidly. The sediment layers that were deposited after this Great Oxidation Event1 show a pronounced change to highly positive carbon isotope values for hundreds of millions of years during a period that has been termed the Lomagundi event2. The coincidence of these two events, which were followed by a comparatively quiescent period in Earth’s history, has long intrigued geoscientists. Writing in Nature Geoscience, Eguchi et al.3 provide an elegantly simple model that mechanistically links both events to differential cycling of carbon in the mantle. They suggest that it is necessary to account for mantle storage, transport and the release of different forms of carbon to accurately interpret Earth’s carbon isotope record.Carbon isotope compositions (expressed as δ13C) in sediments have been interpreted to reflect the balance between carbon burial as carbonate and as organic matter. For most of Earth’s history, the δ13C of carbonates has varied little around 0‰, which is representative of 20% of carbon buried as organic matter and the remainder as carbonate4. In comparison, the δ13C of carbonate rocks is 8–15‰ across the Lomagundi Event. These anomalously high values require an enormous amount of organic carbon burial relative to carbonate burial. However, as organic carbon production generates oxygen, burial of this quantity of organic carbon would mean oxygen production in volumes that are far greater than the concentrations even in today’s relatively oxygen-rich atmosphere. A number of hypotheses have been proposed to address this seemingly massive oxygen imbalance. These range from the weathering of sulfides5 and/or siderites6 to globally distributed pulses of high-δ13C carbonate production in sediments7; however, these hypotheses either treat the Lomagundi Event as mechanistically unrelated to the Great Oxidation Event (GOE) or rely on a slowly growing atmospheric O2 reservoir that triggers large positive feedbacks in surface oxidation reactions: triggers and feedbacks that remain speculative.In using δ13C as a tracer of organic and carbonate carbon burial, a central assumption is that the δ13C composition of volcanic carbon released to the ocean and atmosphere is invariant at –5‰. However, a compilation of carbon isotope data from volcanic CO2 suggests that this value may change depending on the source of volcanic CO2, which can vary between decarbonized carbonates, oxidized organic matter and primitive mantle8.Eguchi and colleagues build this potential for variable volcanic δ13C composition into a carbon cycle model. Their model tracks how differential cycling of subducted carbonate and organic carbon after the GOE would modify the δ13C of volcanic carbon in the following hundreds of millions of years. They posit that a major tectonic trigger — such as a switch from stagnant-lid to plate tectonics — dramatically increased the volcanic flux of CO2 to the atmosphere9, resulting in a nearly immediate, large increase in the flux of weathered materials to the ocean and increased carbonate burial. Concomitantly, these weathered materials delivered phosphorus to the ocean, spurring primary productivity and increasing the flux of organic carbon that is buried in marine sediments.These carbonate- and organic-carbon-rich sediments would have experienced vastly different trajectories through the mantle as they were subducted (Fig. 1). In the hotter mantle of the Paleoproterozoic Earth, carbonates would have been efficiently decarbonized, with the resulting high-δ13C CO2 returned to the atmosphere along island and continental arcs, thereby explaining the anomalously high carbon isotope values of the Lomagundi event. By contrast, the remaining organic carbon in the slab would be converted to refractory graphite or diamond and transported deeper into the mantle. This carbon would only return to the atmosphere much later, once this slab material has been entrained in deep-seated mantle plumes and the carbon oxidized and emitted at ocean island volcanoes. In Eguchi and colleagues’ framework, the relatively quick return of carbonate carbon in arc volcanoes causes the prolonged period of high δ13C in the ocean–atmosphere carbon reservoir; the δ13C Lomagundi excursion only comes to an end once the lower δ13C organic carbon that is stored in the lower mantle is returned to the atmosphere (on the hundred-million-year timescale of whole mantle mixing).Although simple, the framework proposed by Eguchi and colleagues links the Great Oxidation and Lomagundi events with no assumption regarding the amount of carbonate or organic carbon burial; however, as with any simple model, there remain questions. The envisioned tectonic forcing is enormous and requires a one-thousand-fold increase in volcanic CO2 emissions. Even with an efficient weathering feedback10, such an increase would have dramatically increased the radiative forcing due to CO2, potentially conflicting with evidence for large-scale glaciations shortly after the GOE. Furthermore, the change in radiative forcing during the switch from a reducing to oxidized atmosphere would have probably modified the scaling between silicate weathering and climate, which is difficult to capture in a simple model of the silicate weathering response to climate. Even with this large tectonic forcing, the maximum δ13C excursion that is estimated by this carbon cycle model is 5‰, only one-third of the maximum observed δ13C change that is recorded in sediments. Perhaps additional processes that are not represented in this model further modified δ13C. Finally, the residence time of carbonate and organic carbon in the mantle is treated as a single number, whereas the return of these carbon reservoirs to the atmosphere is probably more accurately described as a distribution that would change the shape of the modelled δ13C excursion.Nevertheless, Eguchi et al. demonstrate that differential cycling of carbonate and organic carbon in the mantle can explain enigmatic spikes in carbon isotope compositions in deep time. The findings build on the increasing recognition that δ13C excursions should not be studied in isolation11, but rather as reflections of whole Earth system processes. For those with a focus on the geologic carbon cycle of Earth’s surface, this study is a reminder that whatever carbon goes down into the mantle must eventually come back up.References1. Lyons, T. W., Reinhard, C. T. & Planavsky, N. J. Nature 506, 307–315 (2014).2. Schidlowski, M., Eichmann, R. & Junge, C. E. Geochim. Cosmochim. Acta 40, 449–455 (1976).3. Eguchi, J., Seales, J. & Dasgupta, R. Nat. Geosci. (2019).4. Kump, L. R. & Arthur, M. A. Chem. Geol. 161, 181–198 (1999).5. Bekker, A. & Holland, H. D. Earth Planet. Sci. Lett. 317–318, 295–304 (2012).6. Bachan, A. & Kump, L. R. Proc. Natl Acad. Sci. USA 112, 6562–6567 (2015).7. Schrag, D. P., Higgins, J. A., Macdonald, F. A. & Johnston, D. T. Science 339, 540–543 (2013).8. Mason, E., Edmonds, M. & Turchyn, A. V. Science 357, 290–294 (2017).9. Marty, B., Bekaert, D. B., Broadley, M. W. & Jaupart, C. Geochemical evidence for high volatile fluxes from the mantle at the end of the Archaean. Nature 575, 485–488 (2019).10. Caves, J. K., Jost, A. B., Lau, K. V. & Maher, K. Earth Planet. Sci. Lett. 450, 152–163 (2016).11. Bachan, A. et al. Am. J. Sci. 317, 641–676 (2017).Rytting, B.M., Harper, M.R., Edmond, K.V., Zhang, Y., Kilpatrick, P.K., 2019. High-purity vanadyl petroporphyrins: Their aggregation and effect on the aggregation of asphaltenes. Energy & Fuels 34, 164-178. neutron scattering (SANS) is used to characterize the aggregation of pure vanadyl petroporphyrins (VOPPs), as well as of asphaltenes mixed with either VOPPs or synthetic porphyrins. Simple VOPPs generally form small nanoaggregates, likely dimers and trimers, and have low solubility in toluene and form precipitates. More-complex VOPPs can form large, asphaltene-like nanoaggregates in toluene. Less-functionalized porphyrins are shown to inhibit asphaltene aggregation. More-functionalized porphyrins, potentially having one or more intermolecular interaction sites outside of the central macrocycle, have a tendency to promote aggregation and/or flocculation of asphaltenes at lower temperatures, but have little or no effect at or above room temperature. Highly functionalized porphyrins (petroleum-based and synthetic) are also shown to facilitate asphaltene aggregation, either through the formation of larger nanoaggregates or flocculation, while simpler porphyrins have a tendency to inhibit asphaltene self-assembly.Sahai, N., Schoonen, M.A., 2019. Accuracy of thermodynamic databases for hydroxyapatite dissolution constant. Astrobiology 20, 157-160. have been noted in the solubility constant values of calcium phosphate minerals between various databases employed in widely used aqueous speciation calculation software programs. This can cause serious errors in the calculated speciation of waters when using these software programs. The aim of this communication was to bring to light these discrepancies. Experimental determinations of the hydroxyapatite (HAP) solubility product vary by as much as 10 orders of magnitude as a result of experimental challenges related to the presence of impurities in the HAP used, incongruent dissolution, and the contamination of solutions with dissolved carbon dioxide. It is suggested that the value used in the database Thermo.dat is consistent with experimental data devoid of common experimental problems, whereas other common databases use values that lead to a vastly overestimated solubility of HAP. Saini, R., Hegde, K., Brar, S.K., Vezina, P., 2020. Advanced biofuel production and road to commercialization: An insight into bioconversion potential of Rhodosporidium sp. Biomass and Bioenergy 132, 105439. recent years, Rhodosporidium sp. has received significant interest in advanced biofuel production due to its ability to accumulate more than 60% lipid of their total dry cell weight. Moreover, it can thrive on a wide variety of substrates, has high inhibitor tolerance, and faster growth rate. Despite these advantages and based on current technological advancement, the true potential of Rhodosporidium sp. as a biofuel producer and its commercialization feasibility is still questionable. Thus, this review aims to illustrate the problems that are associated with Rhodosporidium sp. in the field of biofuel production. Apart from this, information regarding factors affecting lipid accumulation, and the role of genetic and metabolic engineering is presented. Additionally, the economic outlook of microbial lipid-derived using lignocellulosic biomass has also been reviewed. Drop-in oil production and its commercialization needs are discussed to bring Rhodosporidium sp. into the limelight and, eventually, to revolutionize the entire biofuel industry.Saint-Vincent, P.M.B., Pekney, N.J., 2020. Beyond-the-meter: Unaccounted sources of methane emissions in the natural gas distribution sector. Environmental Science & Technology 54, 39-49. United States Environmental Protection Agency maintains an inventory of greenhouse gas emissions in accordance with the Intergovernmental Panel on Climate Change. Methane (CH4), a potent gas with a global warming potential 86–125× that of carbon dioxide (CO2) over a twenty-year period, is the main component of natural gas (NG). As NG becomes an increasingly larger percentage of the energy resources used in the United States, it is ever more important to evaluate the CH4 emissions inventory. However, the inventory also does not account for all possible sources of CH4 leaks, contributing to uncertainty in the national CH4 inventory. Discrepancies between top-down and bottom-up inventories of CH4 emissions imply that there are significant unaccounted-for sources of CH4 leaks, especially over cities. Diffuse CH4 plumes above cities that are not attributable to distribution pipelines or other NG infrastructure suggest many small beyond-the-meter leaks together contribute to large emissions. Here, we evaluate the distribution sector of the CH4 emissions inventory and make suggestions to improve the inventory by analyzing end-user emissions. Preliminary research into beyond-the-meter emissions suggests that while individually small, the appliances and buildings that make up the residential sector could contribute significantly to national scale emissions. Furnaces are the most leak-prone of appliances, contributing to 0.14% of total CH4 emissions from the NG sector in the United States. Combining measurements from whole house emissions and steady-state operation of appliances, we estimate that residential homes and appliances could release 9.1 Gg CH4 yearly in the United States, totaling over 2% of the CH4 released from the NG sector. While factors such as appliance age and usage, climate, and residential setting could influence the emissions profile of individual appliances, these preliminary estimates justify further exploration of beyond-the-meter emissions.Sakamoto, T., Qiu, Z., Inagaki, M., Fujimoto, K., 2020. Simultaneous amino acid analysis based on 19F NMR using a modified OPA-derivatization method. Analytical Chemistry 92, 1669-1673. provide alternative methods of analyzing amino acids without liquid chromatography, 19F NMR based simultaneous and individual detection methods for amino acids using o-phthalaldehyde (OPA) based 19F labeling have been developed. Since the chemical shifts of almost all 19F-labeled amino acids differ from each other, and they can be discriminated on the 19F NMR spectrum, simultaneous detection of amino acids has been successfully demonstrated. The discrimination pattern of the peak identical to that of the 19F labeled amino acids was largely dependent on the chemical structure of the thiols having 19F nuclei, strongly suggesting that there is a large potential for clearer discrimination of amino acids by optimizing the thiol structure and/or combined use of thiols.Sakurai, H., Tokanai, F., Miyake, F., Horiuchi, K., Masuda, K., Miyahara, H., Ohyama, M., Sakamoto, M., Mitsutani, T., Moriya, T., 2020. Prolonged production of 14C during the ~660 BCE solar proton event from Japanese tree rings. Scientific Reports 10, 660. rings record the intensity of cosmic rays (CRs) that had entered into the Earth’s atmosphere. Several rapid 14C increases in the past, such as the 775 CE and 994CE 14C spikes, have been reported to originate from extreme solar proton events (SPEs). Another rapid 14C increase, also known as the ca. 660 BCE event in German oak tree rings as well as increases of 10Be and 36Cl in ice cores, was presumed similar to the 775 CE event; however, as the 14C increase of approximately 10‰ in 660 BCE had taken a rather longer rise time of 3–4 years as compared to that of the 775 CE event, the occurrence could not be simply associated to an extreme SPE. In this study, to elucidate the rapid increase in 14C concentrations in tree rings around 660 BCE, we have precisely measured the 14C concentrations of earlywoods and latewoods inside the annual rings of Japanese cedar for the period 669–633 BCE. Based on the feature of 14C production rate calculated from the fine measured profile of the 14C concentrations, we found that the 14C rapid increase occurred within 665–663.5 BCE, and that duration of 14C production describing the event is distributed from one month to 41 months. The possibility of occurrence of consecutive SPEs over up to three years is offered.Salari, Z., Kazemi, M.J., Shirsalimian, M.S., 2020. Isolation and molecular identification of halophilic microorganisms from around Saghand Uranium Mine, Saghand Desert, Iran. Geomicrobiology Journal 37, 40-49. are a group of microorganisms found in salty environments such as marine ecosystems, salty meat, salt evaporation ponds, and salt mines. The present study aimed to investigate the diversity of halophilic microorganisms in Saghand Desert (Yazd Province, Iran). To this end, water, soil, and salt crystal samples were taken from Saghand Desert. In order to isolate and culture bacteria and archaea, they were separately inoculated in solid 10% Halophiles Moderate (HM) medium and 23% Modified Growth Medium (MGM). After incubation at 37?°C, all obtained halophilic isolates were analyzed in terms of phenotypic, microscopic, and biochemical characteristics. After eliminating repetitive strains, 26 isolates from each representative sample were selected for DNA extraction and molecular studies. Phylogenetic analysis showed that archaeal isolates belonged to genera Natrinema and Haloarcula and bacterial isolates were from genera Halomonas, Bacillus, Staphylococcus, and Gracilibacillus. The isolation of these genera from many regions of Iran and their enzymatic activity indicate the high biodiversity of these microorganisms in Iran and their potentials for use in biotechnology, which should be considered by industries more seriously.Sánchez-Romero, M.A., Casadesús, J., 2020. The bacterial epigenome. Nature Reviews Microbiology 18, 7-20. all domains of life, genomes contain epigenetic information superimposed over the nucleotide sequence. Epigenetic signals control DNA–protein interactions and can cause phenotypic change in the absence of mutation. A nearly universal mechanism of epigenetic signalling is DNA methylation. In bacteria, DNA methylation has roles in genome defence, chromosome replication and segregation, nucleoid organization, cell cycle control, DNA repair and regulation of transcription. In many bacterial species, DNA methylation controls reversible switching (phase variation) of gene expression, a phenomenon that generates phenotypic cell variants. The formation of epigenetic lineages enables the adaptation of bacterial populations to harsh or changing environments and modulates the interaction of pathogens with their eukaryotic hosts.Sandoval, B.A., Hyster, T.K., 2020. Emerging strategies for expanding the toolbox of enzymes in biocatalysis. Current Opinion in Chemical Biology 55, 45-51. the repertoire of reactions available to enzymes is an enduring challenge in biocatalysis. Owing to the synthetic versatility of transition metals, metalloenzymes have been favored targets for achieving new catalytic functions. Although less well explored, enzymes lacking metal centers can also be effective catalysts for non-natural reactions, providing access to reaction modalities that compliment those available to metals. By understanding how these activation modes can reveal new functions, strategies can be developed to access novel biocatalytic reactions. This review will cover discoveries in the last two years which access catalytic reactions that go beyond the native repertoire of metal-free biocatalysts.Sa?é, E., Ingrassia, M., Martorelli, E., Chiocci, F.L., 2020. Amino acids in surface sediments of the Zannone Island shelf (Western Mediterranean Sea): Possible bioindicators of submarine hydrothermal activity. Organic Geochemistry 140, 103960. study shows results from amino acid analysis of seafloor sediment sampled between ~80 and ~130 m depth, within an active hydrothermal field located off Zannone Island (Tyrrhenian Sea). The total hydrolysable amino acid (THAA) content was determined at eight stations, three located within the main hydrothermal depression (i.e. the Zannone Giant Pockmark, ZGP) and five located in the surrounding seafloor. THAA concentration ranged between ~2 and ~11 nmol mg?1 dw and the lowest THAA concentrations were found at stations located within the ZGP. Amino acids resistant to degradation or originating from bacteria (β-alanine, histidine, leucine, arginine and lysine) had higher relative abundances inside the ZGP, whereas amino acids susceptible to degradation or originating from cellular plasma (proline, phenylalanine and tyrosine) showed higher relative abundances outside the ZGP. Degradation and reactivity indices were calculated, and the sedimentary organic matter in the three outside ZGP stations B07, B08 and B09 was found to be the most labile and reactive. Together with THAA concentrations, sediment grain size and carbon percentages were measured at 12 stations, five located within the ZGP and seven located outside the ZGP. At all stations, the percentage of sand was ~75% or higher. Carbon percentages were lower in samples located inside the ZGP than in the surrounding stations. The southern outside ZGP station B12 was found to be similar in terms of amino acids composition to the three inside ZGP stations, suggesting the influence of the hydrothermal fluids at this station.Sankaran, R., Parra Cruz, R.A., Pakalapati, H., Show, P.L., Ling, T.C., Chen, W.-H., Tao, Y., 2020. Recent advances in the pretreatment of microalgal and lignocellulosic biomass: A comprehensive review. Bioresource Technology 298, 122476. and lignocellulosic biomass is the most sumptuous renewable bioresource raw material existing on earth. Recently, the bioconversion of biomass into biofuels have received significant attention replacing fossil fuels. Pretreatment of biomass is a critical process in the conversion due to the nature and structure of the biomass cell wall that is complex. Although green technologies for biofuel production are advancing, the productivity and yield from these techniques are low. Over the past years, various pretreatment techniques have been developed and successfully employed to improve the technology. This paper presents an in-depth review of the recent advancement of pretreatment methods focusing on microalgal and lignocellulosic biomass. The technological approaches involving physical, chemical, biological and other latest pretreatment methods are reviewed.Santana, A., Comas, A., Wise, S., Wilson, W.B., Campiglia, A.D., 2020. Instrumental improvements for the trace analysis of structural isomers of polycyclic aromatic hydrocarbons with molecular mass 302?Da. Analytica Chimica Acta 1100, 163-173. aromatic hydrocarbons (PAHs) are some of the most common environmental pollutants encountered worldwide. Eco-toxicological studies attribute a significant portion of the biological activity of PAH contaminated samples to the presence of high molecular weight PAHs (HMW-PAHs), i.e. PAHs with molecular mass (MM) greater than 300?Da. The research presented here focuses on the analysis of PAH isomers of MM 302?Da. This is not a trivial task. There are 23 isomers with MM 302?Da available to commercial and academic researchers. Many of them are difficult to separate in the chromatographic column and have virtually identical fragmentation patterns. The selectivity of HPLC absorption and fluorescence detectors is modest for resolving co-eluting isomers. Previous work in our lab demonstrated the potential of laser excited time-resolved Shpol’skii spectroscopy (LETRSS) for the analysis of 302?Da isomers in HPLC fractions. The main limitation of the technique was instrumental and due to the narrow range of excitation wavelengths of the tunable dye laser used for sample excitation. Herein, we remove this limitation with an optical parametric oscillator (OPO)-based wavelength tuning laser that covers the whole excitation range of 302?Da isomers. It is possible now to excite each isomer at its excitation wavelength for maximum fluorescence emission and reach limits of detection at the parts-per-trillion level (pg.mL?1). The excitation bandwidth of the OPO laser (0.2?nm) is a good match for the narrow excitation spectra of 302?Da isomers in n-octane. This feature, associated to unique vibrational fluorescence profiles and lifetime decays, allows for the unambiguous identification of co-eluting isomers in RPLC fractions. The same is true for their quantitative analysis in coal tar samples.Santos, S.M., Nascimento, D.C., Costa, M.C., Neto, A.M.B., Fregolente, L.V., 2020. Flash point prediction: Reviewing empirical models for hydrocarbons, petroleum fraction, biodiesel, and blends. Fuel 263, 116375. Point (FP) of fuels is essential to determine the requirements for transportation and storage temperature. FP may be a restriction for incorporating light fractions into final products; therefore, accurate prediction models are necessary. However, finding the most accurate prediction model might be a challenge due to the high variety of methods. Hence, we reviewed empirical correlations, the simplest approach to predict FP of pure hydrocarbons, petroleum fractions, blends and biodiesel-FAME once it does not require complex calculation and known composition. Those correlations originally adjusted for pure hydrocarbons were extended to predict FP of petroleum fractions and, vice-versa, to verify the possibility of extension of the models. In addition, empirical models based on blending indexes were tested to predict FP of blends of diesel-biodiesel and hydrocarbons, which were also compared to Liaw’s model. The empirical models were assessed using experimental data from literature and from Brazilian refineries. As a result, there is not only one reasonable method for FP estimation of those compounds. It depends on the type of hydrocarbons, range of FP, and ideality and volumetric fraction for blending systems. In addition, we obtained a reasonable result for biodiesel FP prediction from specific vegetable oils by applying kinematic viscosity with AAD?=?4.14?K. For petroleum fractions (distillation range from 340?K to 505?K), unexpectedly, a method firstly developed for pure compounds presented the most satisfactory performance with AAD?=?8.11?K. Finally, we developed a new model to estimate flash point of Brazilian diesel fractions S500 with AAD?=?2.11?K.Sanz-Robinson, J., Williams-Jones, A.E., 2020. The solubility of Nickel (Ni) in crude oil at 150, 200 and 250?°C and its application to ore genesis. Chemical Geology 533, 119443. very low solubility of Ni in saline brines and the correspondingly high concentration of Ni in some crude oils raise the possibility that liquid hydrocarbons may be the ore fluids for black-shale-hosted Ni deposits. To test the feasibility of this hypothesis, Ni wires were reacted with three crude oils of differing composition at 150, 200 and 250?°C for up to 30?days, and the concentration of Ni in the oil determined. At 150?°C, Ni concentrations in the three oils remained relatively low. Above 200?°C, however, Ni concentrations were elevated and correlated positively with the thiol content of the oil. Our most thiol-rich oil dissolved 217?±?40.4?ppm Ni after 30?days at 250?°C. X-ray photoelectron spectroscopic (XPS) analyses performed on the residual oil coating the Ni wires after reaction independently corroborate the conclusion that Ni has a strong chemical affinity for thiols in crude oil. In crude oils with no thiols, the Ni reacted with other sulfur compounds (potentially sulfonic acids) to form thiols. Significantly, our XPS analyses show that iron (Fe) from the oil was embedded in the Ni wire synchronously with the attachment of thiols. This suggests that Fe has an affinity for Ni and that the thiolation of Ni by crude oil may depend on the availability of Fe in the oil. In addition to thiols, porphyrins also likely play an important role in the dissolution of Ni, as shown by the fact that the oil in which Ni was most soluble has a high nitrogen content, whereas in the other oil, which is characterized by a high thiol content, the Ni solubility was relatively low and the nitrogen content of this oil was below the detection limit. Immature biodegraded oils that are sourced from carbonate rocks generally tend to be enriched in asphaltenes, Ni and sulfur. Nevertheless, some mature oils acquire anomalously large thiol contents through Thermochemical Sulfate Reduction (TSR), a high temperature (100 to 140?°C) reaction occurring commonly in carbonate reservoirs, which involves the abiotic reduction of sulfate minerals at the expense of oil or bitumen. Thus, given the affinity of Ni for thiols, large volumes of Ni-poor oil can potentially be altered by TSR to produce smaller volumes of residual oil enriched in thiols and Ni.Sardi, S.S., Qurban, M.A., Li, W., Kadinjappalli, K.P., Manikandan, P.K., Hariri, M.M., Tawabini, B.S., Khalil, A.B., El-Askary, H., 2020. Assessment of areas environmentally sensitive to oil spills in the western Arabian Gulf, Saudi Arabia, for planning and undertaking an effective response. Marine Pollution Bulletin 150, 110588. comprehensive environmental sensitivity index was prepared and ESM maps generated. Impact of Gulf War Oil Spill in 1991 impact on a mangrove habitat was assessed using Landsat imageries. Impact probability of oil spill are calculated through General NOAA Operational Modeling Environment/Automated Data Inquiry for Oil Spills (GNOME/ADIOS) model simulation. Areas with the highest priority for protection in case of an oil spill were demarcated for the development of immediate response plans.Sasmito, S.D., Kuzyakov, Y., Lubis, A.A., Murdiyarso, D., Hutley, L.B., Bachri, S., Friess, D.A., Martius, C., Borchard, N., 2020. Organic carbon burial and sources in soils of coastal mudflat and mangrove ecosystems. CATENA 187, 104414. organic carbon is primarily stored in soils, which contain more than two-thirds of total mangrove ecosystem carbon stocks. Despite increasing recognition of the critical role of mangrove ecosystems for climate change mitigation, there is limited understanding of soil organic carbon sequestration mechanisms in undisturbed low-latitude mangroves, specifically on organic carbon burial rates and sources. This study assessed soil organic carbon burial rates, sources and stocks across an undisturbed coastal mudflat and mangrove hydrogeomorphological catena (fringe mangrove and interior mangrove) in Bintuni Bay, West Papua Province, Indonesia. 210Pb radionuclide sediment dating, and mixing model of natural stable isotope signatures (δ 13C and δ15N) and C/N ratio were used to estimate organic carbon burial rates and to quantify proportions of allochthonous (i.e., upland terrestrial forest) and autochthonous (i.e., on-site mangrove forest) organic carbon in the top 50 cm of the soil. Burial rates were in the range of 0.21–1.19 Mg C ha?1 yr?1. Compared to the fringe mangroves, organic carbon burial rates in interior mangroves were almost twice as high. Primary productivity of C3 upland forest vegetation and mangroves induced soil organic carbon burial in interior mangroves and this was consistent with the formation of the largest organic carbon stocks (179 ± 82 Mg C ha?1). By contrast, organic carbon stored in the fringe mangrove (68 ± 11 Mg C ha?1) and mudflat (62 ± 10 Mg C ha?1) soils mainly originated from upland forests (allochthonous origin). These findings clearly indicate that carbon sequestered and cycling in mangrove and terrestrial forest ecosystems are closely linked, and at least a part of carbon losses (e.g., erosion) from terrestrial forests is buried in mangrove ecosystems.Saupe, E.E., Qiao, H., Donnadieu, Y., Farnsworth, A., Kennedy-Asser, A.T., Ladant, J.-B., Lunt, D.J., Pohl, A., Valdes, P., Finnegan, S., 2020. Extinction intensity during Ordovician and Cenozoic glaciations explained by cooling and palaeogeography. Nature Geoscience 13, 65-70. striking feature of the marine fossil record is the variable intensity of extinction during superficially similar climate transitions. Here we combine climate models and species trait simulations to explore the degree to which differing palaeogeographic boundary conditions and differing magnitudes of cooling and glaciation can explain the relative intensity of marine extinction during greenhouse–icehouse transitions in the Late Ordovician and the Cenozoic. Simulations modelled the response of virtual species to cooling climate using a spatially explicit cellular automaton algorithm. We find that palaeogeography alone may be a contributing factor, as identical changes in meridional sea surface temperature gradients caused greater extinction in Late Ordovician simulations than in Cenozoic simulations. Differences in extinction from palaeogeography are significant, but by themselves are insufficient to explain observed differences in extinction intensity. However, when simulations included inferred changes in continental flooding and interval-specific models of sea surface temperature, predicted differences in relative extinction intensity were more consistent with observations from the fossil record. Our results support the hypothesis that intense extinction in the Late Ordovician is partially attributable to exceptionally rapid and severe cooling compared to Cenozoic events.Schena, T., Lazzari, E., Primaz, C., Canielas Krause, L., Machado, M.E., Bastos Caram?o, E., 2020. Upgrading of coconut fibers bio-oil: An investigation by GC×GC/TOFMS. Journal of Environmental Chemical Engineering 8, 103662. of agroindustrial waste is an important way to add value to this material avoiding its discard in the environment. However, when residues are derived from oilseeds or similar, it is possible to find a large amount of fatty acid derivatives in the biomass and later in bio-oil composition. These compounds are not adequately thermo-degraded in pyrolysis processes, reducing the quality. Another common compound class and with a high added value present in bio-oils are phenols. In this work two forms of upgrading processes were performed in coconut fiber pyrolysis process. One of them is the alkaline extraction of coconut fiber bio-oil in order to produce a high acidic and a neutral fraction. The other upgrading process is a biomass pretreatment before the pyrolysis, using two different extraction techniques (Soxhlet and ultrasound). The two processes proved to be efficient and complimentary: in the first case, there was the pre-concentration of the phenols in a single fraction and in the second one, a great part of the fatty acids derivatives were removed from the bi-oil. These results indicate that the two techniques can be used to improve the quality of bio-oil produced by removing the free fatty acids from biomass and isolating compounds with high added value (in the case of phenols).Schiffbauer, J.D., Selly, T., Jacquet, S.M., Merz, R.A., Nelson, L.L., Strange, M.A., Cai, Y., Smith, E.F., 2020. Discovery of bilaterian-type through-guts in cloudinomorphs from the terminal Ediacaran Period. Nature Communications 11, 205. fossil record of the terminal Ediacaran Period is typified by the iconic index fossil Cloudina and its relatives. These tube-dwellers are presumed to be primitive metazoans, but resolving their phylogenetic identity has remained a point of contention. The root of the problem is a lack of diagnostic features; that is, phylogenetic interpretations have largely centered on the only available source of information—their external tubes. Here, using tomographic analyses of fossils from the Wood Canyon Formation (Nevada, USA), we report evidence of recognizable soft tissues within their external tubes. Although alternative interpretations are plausible, these internal cylindrical structures may be most appropriately interpreted as digestive tracts, which would be, to date, the earliest-known occurrence of such features in the fossil record. If this interpretation is correct, their nature as one-way through-guts not only provides evidence for establishing these fossils as definitive bilaterians but also has implications for the long-debated phylogenetic position of the broader cloudinomorphs.Schmieder, M., Kring, D.A., 2019. Earth's impact events through geologic time: A list of recommended ages for terrestrial impact structures and deposits. Astrobiology 20, 91-141.. 2085This article presents a current (as of September 2019) list of recommended ages for proven terrestrial impact structures (n?=?200) and deposits (n?=?46) sourced from the primary literature. High-precision impact ages can be used to (1) reconstruct and quantify the impact flux in the inner Solar System and, in particular, the Earth–Moon system, thereby placing constraints on the delivery of extraterrestrial mass accreted on Earth through geologic time; (2) utilize impact ejecta as event markers in the stratigraphic record and to refine bio- and magneto-stratigraphy; (3) test models and hypotheses of synchronous double or multiple impact events in the terrestrial record; (4) assess the potential link between large impacts, mass extinctions, and diversification events in the biosphere; and (5) constrain the duration of melt sheet crystallization in large impact basins and the lifetime of hydrothermal systems in cooling impact craters, which may have served as habitats for microbial life on the early Earth and, possibly, Mars.Scott, A.C., Collinson, M.E., 2020. A note on the charring of spores and implications for coal petrographic analysis and maceral nomenclature. International Journal of Coal Geology 219, 103361. walls have inherently low reflectance (although this will rise with increasing rank) and are assigned to the liptinite maceral sporinite using a combination of their reflectance properties and their morphology that reflects their botanical origin. However, when fern and lycopod spores are charred their reflectance increases. Charred spores, therefore, should be assigned to the inertinite maceral group based upon reflectance properties. At higher rank levels such as anthracites the distinction of macerals using reflectance would become more problematic. Based on morphology some charred spores could appear to be assignable to the fusinite, semifusinite or funginite macerals, none of which would be correct because they are neither a single plant cell nor fungal in origin. At 500?°C and above Lycopodium spores coalesced resulting in material that would be classified as macrinite, one of the inertinite group macerals, adding yet another possible origin to those already known for that maceral. Experiments on pollen have yet to be undertaken, however spores are a more suitable experimental material being present from Paleozoic to Recent. This research further underlines the complexities of maceral formation and the difficulties of identification linked to the combination of physical and biological properties used in the definitions. It is concluded that maceral analysis may not always be an appropriate or reliable method for interpretation of peat/coal formation and composition.Scott, G.R., Irish, J.D., Martinón-Torres, M., 2020. A more comprehensive view of the Denisovan 3-rooted lower second molar from Xiahe. Proceedings of the National Academy of Sciences 117, 37. et al. (1) describe a lower second molar with 3 roots in a Denisovan hemimandible dated 160,000 ka. The presence of a third root is stated to occur in &amp;lt;3.5% of non-Asians and in up to 40% of Asians and some New World populations. From this, they conclude the feature “provides morphological evidence of a strong link between archaic and recent Asian H[omo] sapiens populations. This link provides compelling evidence that modern Asian lineages acquired the 3-rooted lower molar via introgression from Denisovans” (ref. 1, p. 14806). However, there are 2 problems regarding this statement:1) While the expression of 3-rooted lower first molars (LM1) is more common in Asian and Asian-derived ....Original Article: Bailey, S.E., Hublin, J.-J., Antón, S.C., 2019. Rare dental trait provides morphological evidence of archaic introgression in Asian fossil record, PNAS 116 (30) 14806-14807.Reply to Comment: Bailey, S.E., Kupczik, K., Hublin, J.-J., Antón, S.C., 2020. Reply to Scott et al: A closer look at the 3-rooted lower second molar of an archaic human from Xiahe. Proceedings of the National Academy of Sciences 117, 39.Senatore, G., Mastroleo, F., Leys, N., Mauriello, G., 2020. Growth of Lactobacillus reuteri DSM17938 under two simulated microgravity systems: Changes in reuterin production, gastrointestinal passage resistance, and stress genes expression response. Astrobiology 20, 1-14. factors such as space microgravity, radiation, and magnetic field differ from those that occur on Earth. Microgravity may induce and select some microorganisms for physiological, metabolic, and/or genetic variations. This study was conducted to determine the effects of simulated microgravity conditions on the metabolism and gene expression of the probiotic bacterium Lactobacillus reuteri DSM17938. To investigate microbial response to simulated microgravity, two devices—the rotating wall vessel (RWV) and the random positioning machine (RPM)—were used. Microbial growth, reuterin production, and resistance to gastrointestinal passage were assessed, and morphological characteristics were analyzed by scanning electron microscopy. The expression of some selected genes that are responsive to stress conditions and to bile salts stress was evaluated through real-time quantitative polymerase chain reaction assay. Monitoring of bacterial growth, cell size, and shape under simulated microgravity did not reveal differences compared with 1?×?g controls. On the contrary, an enhanced production of reuterin and a greater tolerance to the gastrointestinal passage were observed. Moreover, some stress genes were upregulated under RWV conditions, especially after 24?h of treatment, whereas RPM conditions seemed to determine a downregulation over time of the same stress genes. These results show that simulated microgravity could alter some physiological characteristics of L. reuteri DSM17938 with regard to tolerance toward stress conditions encountered on space missions and could be useful to elucidate the adaptation mechanisms of microbes to the space environment.Sharma, V., Sircar, A., 2020. Multi-technique characterization of shale reservoir quality parameters. Journal of Natural Gas Science and Engineering 75, 103125. multitechnique characterization approach has been used to quantitatively and qualitatively evaluate all the reservoir quality parameters, crucial for the exploitation and development of unconventional shale plays. Characterization methods, in particular FTIR, XRF, NMR, MICP, HPP, LPP and High Pressure Permeameter were used on selected 20 younger and older shale samples of Cambay to determine their true petrophysics, mineralogy, brittleness and fracability potential with respect to depth. Properties mainly porosity, permeability, pore size distribution, mineralogy, brittleness, pore sizes and fracability were determined. It was found that younger cambay has medium size pores with high porosity, low silica and high clay content. On the contrary, older cambay has good pore connectivity, rich in organic and clay content, fair brittleness index and capable of producing hydrocarbons. The performed multidisciplinary analysis is first of its kind research and will go a long way in shale gas research and development in India at pilot scale. The generated data can be helpful in minimizing the research gap and hence the challenges associated with the commercial development of these prolific shales.Shen, P., Li, G., Li, B., Li, X., Liang, Y., Lv, Q., 2020. Permeability measurement and discovery of dissociation process of hydrate sediments. Journal of Natural Gas Science and Engineering 75, 103155. study on the permeability of methane hydrates in fine quartz sands contributes to the accurate prediction of gas/water production and can effectively express the characteristics of fluid migration. In this study, the water effective permeability (kw) of methane hydrates in three fine quartz sands containing various hydrate saturation (SH) were carried out under steady water injection and production. Experimental results indicated that the effect of particle sizes on kw was significant even though the difference in the average particle size of three fine quartz sands was relatively limited. The differential pressure of the hydrate sediments was completely recorded during permeability measurement, and the stabilization and decomposition process of hydrate could be clearly represented by differential pressure. The kw increased rapidly with the decomposition of hydrate and the appearance of flow channel in the hydrate sediments. Hydrate dissociation process was recorded in situ by Cold Field Emission Scanning Electron Microscopy (CFE–SEM), the dissociation of hydrates in pore space was clearly visible, and the hydrates in pore space were first dissociated into many small regions. A new reduction model between water relative permeability (krw) and SH was proposed on the basis of experimental results, and the experimental data fitted well with hydrates occupying pore centers. The effect of particle sizes on krw was eliminated, the Archie saturation exponent n tended to increase with the increase of SH, and n was recommended between 20 and 30.Shi, D., Bera, G., Knap, A.H., Quigg, A., Al Atwah, I., Gold-Bouchot, G., Wade, T.L., 2020. A mesocosm experiment to determine half-lives of individual hydrocarbons in simulated oil spill scenarios with and without the dispersant, Corexit. Marine Pollution Bulletin 151, 110804., we report results from a 15-day mesocosm experiment examining changes in estimated oil equivalents (EOEs), n-alkanes (n-C10 to n-C35), polycyclic aromatic hydrocarbons (PAHs) and petroleum biomarkers. Water accommodated fractions (WAF) of oil and diluted chemically enhanced WAF (DCEWAF) were prepared and concentrations of oil residues determined on day 0, 3 and 15, respectively. Significant removals of n-alkane and PAHs were observed starting from day 3. The n-C17/pristane and n-C18/phytane ratios suggested that the n-alkane removal was due to biodegradation in the mesocosms. The ratios of C2-dibenzothiophenes/C2-phenanthrenes (D2/P2) and C3-dibenzothiophenes/C3-phenanthrenes (D3/P3) were found to be stable through the experiment. DCEWAF treatment had longer half-lives for most n-alkanes but shorter half-lives for most PAHs than the WAF treatment. Most petroleum biomarkers were stable throughout the experiment. However, depletion of TAS (tricyclic aromatic steroids) was observed on day 15 of DCEWAF treatment.Shi, X., Qiu, X., Cheng, Z., Chen, Q., Rudich, Y., Zhu, T., 2020. Isomeric identification of particle-phase organic nitrates through gas chromatography and time-of-flight mass spectrometry coupled with an electron capture negative ionization source. Environmental Science & Technology 54, 707-713. nitrates (ONs) are an important component of secondary organic aerosols that play significant roles in atmospheric chemical processes such as ozone formation and as a reservoir of nitrogen oxides (NOx). However, hindered by the availability of analytical techniques, characteristics of ON molecules remain unclear in regions influenced by anthropogenic volatile organic compounds (VOCs) and pollution. In this study, we achieved isomeric identification of particle-phase ONs in such regions. Using gas chromatography and time-of-flight mass spectrometry with an electron capture negative ionization source, we established a systematic procedure for screening unknown ONs in fine particulate matter (PM) collected in Beijing based primarily on the characteristic fragment ions of NO2– and [M–NO2]?/[M–NO2–H2]?. We found 78 ON candidates, 12 of which were confirmed using synthesized standards. Seventy-three of these detected ONs might originate from anthropogenic VOC precursors especially alkenes. Significantly, we observed two isomers generated from straight-chain 1-alkenes, namely, 2-hydroxy-1-nitrate and 1-hydroxy-2-nitrate. The signal ratios of the two isomers suggested that these hydroxy nitrates are mainly produced photochemically rather than through nighttime reactions. This study provides a promising method for identifying ONs in atmospheric PM and elucidating their formation pathways.Shoukry, A.E., El-Banbi, A.H., Sayyouh, H., 2020. Enhancing asphaltene precipitation modeling by cubic-PR solid model using thermodynamic correlations and averaging techniques. Petroleum Science 17, 232–241. equation-of-state solid models are one of the most widely used models to predict asphaltene precipitation behavior. Thermodynamic parameters are needed to model precipitation under different pressures and temperatures and are usually obtained through tuning with multi?asphaltene onset experiments. For the purpose of enhancing the cubic Peng–Robinson solid model and reducing its dependency on asphaltene experiments, this paper tests the use of aromatics and waxes correlations to obtain these thermodynamic parameters. In addition, weighted averages between both correlations are introduced. The averaging is based on reported saturates, aromatics, resins, asphaltene (SARA) fractions, and wax content. All the methods are tested on four oil samples, with previously published data, covering precipitation and onset experiments. The proposed wax-asphaltene average showed the best match with experimental data, followed by a SARA-weighted average. This new addition enhances the model predictability and agrees with the general molecular structure of asphaltene molecules.Shu, R., Li, R., Lin, B., Wang, C., Cheng, Z., Chen, Y., 2020. A review on the catalytic hydrodeoxygenation of lignin-derived phenolic compounds and the conversion of raw lignin to hydrocarbon liquid fuels. Biomass and Bioenergy 132, 105432., one of the fossil fuels, is still the main source for liquid fuel production. Lignin derived from renewable biomass has the potential to replace petroleum. The abundance of aromatic units in lignin makes it potential to produce high-value liquid fuel. This review offers a summary of the extensive study that has been devoted to the catalytic hydrodeoxygenation (HDO) of lignin-derived phenolic compounds and the conversion of raw lignin into hydrocarbon liquid fuels. Based on the product classification (cyclohexanes and arenes), different catalytic systems, mainly including catalyst species, solvents and reaction conditions, are analyzed in detail. A model study of lignin-derived compounds (phenolic monomers and dimers) is usually carried out to elaborate on the HDO reaction mechanism. 100% yield of hydrocarbon liquid fuels can be achieved in most tests. With respect to the real lignin-derived bio-oil, however, hydrocarbon yields only reach 16.2%–62.8% due to the various components and high instability of the substrate. The technical barriers and challenges in this part are highlighted throughout. Moreover, the conversion of raw lignin is also comprehensively summarized, which actually combines the depolymerization of lignin and HDO of lignin-derived bio-oil in one pot, and its hydrocarbon yields are generally lower than those of lignin-derived bio-oil. In light of this, the important features of raw lignin that influence the production of hydrocarbon liquid fuels are adequately addressed. Overall, this paper focuses on the scientific and technological advances of hydrocarbon liquid fuel production from lignin, and the potential strategies to produce renewable fuels from lignin are discussed.Sieh, K., Herrin, J., Jicha, B., Schonwalder Angel, D., Moore, J.D.P., Banerjee, P., Wiwegwin, W., Sihavong, V., Singer, B., Chualaowanich, T., Charusiri, P., 2020. Australasian impact crater buried under the Bolaven volcanic field, Southern Laos. Proceedings of the National Academy of Sciences 117, 1346-1353.: A field of black glassy blobs, strewn across about 20% of Earth’s Eastern Hemisphere, resulted from the impact of a large meteorite about 790,000 y ago. The large crater from which these tektites originated has eluded discovery for over a century, although evidence has long pointed to a location somewhere within Indochina, near the northern limit of the strewn field. We present stratigraphic, geochemical, geophysical, and geochronological evidence that the ～15-km diameter crater lies buried beneath a large, young volcanic field in Southern Laos.Abstract: The crater and proximal effects of the largest known young meteorite impact on Earth have eluded discovery for nearly a century. We present 4 lines of evidence that the 0.79-Ma impact crater of the Australasian tektites lies buried beneath lavas of a long-lived, 910-km3 volcanic field in Southern Laos: 1) Tektite geochemistry implies the presence of young, weathered basalts at the site at the time of the impact. 2) Geologic mapping and 40Ar-39Ar dates confirm that both pre- and postimpact basaltic lavas exist at the proposed impact site and that postimpact basalts wholly cover it. 3) A gravity anomaly there may also reflect the presence of a buried ～17 × 13-km crater. 4) The nature of an outcrop of thick, crudely layered, bouldery sandstone and mudstone breccia 10–20 km from the center of the impact and fractured quartz grains within its boulder clasts support its being part of the proximal ejecta blanket.Siqueira, J.G.W., Rodrigues, C., Vandenberghe, L.P.d.S., Woiciechowski, A.L., Soccol, C.R., 2020. Current advances in on-site cellulase production and application on lignocellulosic biomass conversion to biofuels: A review. Biomass and Bioenergy 132, 105419. potential of lignocellulosic feedstock has been widely studied, mainly for biofuels production, which usually requires an enzymatic step on the process. Cellulolytic enzymes have been studied as input for bioconversion and as a product from lignocellulose fermentation. The integration of these two perspectives may lead to an economically viable approach for second generation biofuels production, which is nowadays difficult due to high cost of commercial cellulase. Conversely, enzyme production by fermentation of lignocellulosic substrates is inexpensive and the hydrolytic activity of enzymes produced on these substrates, which are to be hydrolyzed, may be better than those enzymes produced on other materials, such as cellulose. Many studies have defined the ideal conditions for cellulase production and saccharification processes separately. In contrast, few reports have developed a unique and integrated process, based on the same feedstock. This review is focused on current advances and innovation in on-site cellulolytic enzymes production using plant biomass, and application of the enzymes in lignocellulose conversion to fermentable sugars for biofuel production.Siveter, D.J., Briggs, D.E.G., Siveter, D.J., Sutton, M.D., 2020. The Herefordshire Lagerst?tte: fleshing out Silurian marine life. Journal of the Geological Society 177, 1-13. Herefordshire Lagerst?tte (c. 430?Ma) from the UK is a rare example of soft-tissue preservation in the Silurian. It yields a wide range of invertebrates in unparalleled three-dimensional detail, dominated by arthropods and sponges. The fossils are exceptionally preserved as calcitic void infills in early diagenetic carbonate concretions within a volcaniclastic (bentonite) horizon. The Lagerst?tte occurs in an outer shelf/upper slope setting in the Welsh Basin, which was located on Avalonia in the southern subtropics. The specimens are investigated by serial grinding, digital photography and rendering in the round as ‘virtual fossils’ by computer. The fossils contribute much to our understanding of the palaeobiology and early history of the groups represented. They are important in demonstrating unusual character combinations that illuminate relationships; in calibrating molecular clocks; in variously linking with taxa in both earlier and later Paleozoic Lagerst?tten; and in providing evidence of the early evolution of crown-group representatives of several groups.Snyder, G.T., Sano, Y., Takahata, N., Matsumoto, R., Kakizaki, Y., Tomaru, H., 2020. Magmatic fluids play a role in the development of active gas chimneys and massive gas hydrates in the Japan Sea. Chemical Geology 535, 119462. Earth's marine continental margins hold significant amount of carbon in the form of gas hydrate which can interact dynamically with seawater and the atmosphere and potentially influence global climate. It is generally assumed that degradation of organic matter, through either biogenic or thermogenic processes, is responsible for the majority of the gas hydrate presently found in these deposits. We present stable isotope and noble gas results from gas hydrates in the eastern margin of the Japan Sea and compare them with previously published data regarding gases which are found nearby in deep hydrocarbon wells associated with Early Miocene igneous and sedimentary rocks. Our results show that most of the gases which accumulate in the hydrate can be described as a mixture between a deeply-sourced methane-rich thermogenic/crustal source (TC), a methane-rich admixture of biogenic gases with relatively shallow air-saturated seawater (BASW) and a methane-poor magmatic-mantle source (MM). The presence of hydrate with a mantle 3He/4He signatures indicates that fluids enriched in mantle gases are responsible for the mobilization of thermogenic gas within active Japan Sea chimney structures. The growth of primary hydrate at shallow marine sediment depths is ongoing, as is the cycling of gas to hydrate which is eventually buried and dissociated at the base of the gas hydrate stability zone, leading to large pockmark structures.Sojinu, O.S., 2020. Preliminary evaluation of bitumen contamination in environmental samples using comprehensive gas chromatography GC×GC – Time of flight mass spectrometry (GC×GC-TOFMS). Environmental Forensics 21, 79-86. and bitumen impacted soil and water samples were investigated for their relative chemical composition using comprehensive gas chromatography GCxGC - time of flight mass spectrometry (GC×GC-TOFMS). The results reveal the presence of key compounds which could serve as environmental biomarkers for bitumen impacted soils and aquifers. Prominent alkanes such as 3-methylpentane; 2,2,4-trimethylpentane; 1,3,5-trimethyladamantane; 2,6,10-trimethyldodecane; 3-ethyl-2,2-dimethyl pentane were tentatively identified and are likely potent biomarkers in environmental forensic assessment of bitumen contamination while the presence of some aromatic compounds: 1,2-benzenedicarboxylic acid, 1,2-dimethyl-3-propylbenzene; 3,4-bis(methoxycarbonyl)benzoic acid; 1,3-bezenedicarboxylic acid, 1,2-benzenediol; 1,3-dimethylbenzene; 1,2-2-(2-ethylhexoxycarbonyl)benzoic acid; (4-methylpentan-2-yl)benzene; 2,4-dimethyl benzo(H)quinolone will further confirm the bitumen contamination in an area under investigation. A host of additional compounds were tentatively identified, mainly in the bitumen samples. The results obtained in this study provides baseline data for effective monitoring, and source apportionment of oil/oil products spills.S?lling, T.I., Olesen, K.B., Palm-Henriksen, G., Abdel-Azeim, S., Skov, A.B., 2020. Crystalizing the interface – The first X-Ray structure of an oil/surfactant/brine transition layer. Journal of Petroleum Science and Engineering 188, 106953. interfacial phenomena are central in a wide variety of scientific disciplines and encompass down-to-earth aspects such as mayonnaise production, more complex processes in cellular biology and determine what drives the flow below the surface of the earth in an oil reservoir. It is the actual molecular structure at the boundary between two immiscible liquids that determines the interfacial properties. The experimental determination of such a structure has previously been unsuccessful. We have designed an experiment to enable crystallization of the interface between brine and a surfactant/organic phase. A single-crystal structure reveals, for the first time, how the structure and orientation of surfactants impact macroscopic measures such as interfacial tension.Song, D., Tuo, J., Wang, Y., Wu, C., Zhang, M., 2019. Research advances on characteristics of nanopore structure of organic-rich shales. Acta Sedimentologica Sinica 37, 1309-1324. full understanding of the properties of the pore structure in organic-rich shales is beneficial for determining the shale oil and gas accumulation mechanism,and thus is significant in guiding exploration and exploitation. Methods of characterizing the pore structure of organic-rich shales embody quantitative analysis and qualitative description,both of which should be combined during investigations. Factors such as total organic carbon(TOC),thermal maturity,origin of organic matter,mineral constituents and tectonism have considerable impacts on the nature of the pore structure in organic-rich shales. Of these,the origin of organic matter determines the potential for organic pores formation;TOC and mineralogy control the types of nanopores;and thermal maturity influences nanopore evolution. Tectonism has a secondary effect,in that it may modify the nanopore structure. Pyrolysis experiments play a crucial role in investigating the evolution of pore structure in shales,since the factors are controlled artificially;however,experimental conditions should match the actual geological conditions. At present,pore structure evolution in shales is still inconclusive and controversial. Due to the diverse origins of organic matter,the evolution of the pore structure in organic-rich shales may differ from one sedimentary environment to another,and thus require further separate study. Dilemmas such as the impacts of TOC on the characteristics of pores in shales,the mature stage of the development of secondary organic pores and the evolutionary scenarios and mechanisms of pores at the envolution stage (Ro>3%) need to be further explored. In addition,the methods identifying the microscopic compositions of organic matter using scanning electron microscopy need to be established,and the usage of some terminologies should be standardized to reduce the confusion that is currently caused by researchers who engage in different fields.Song, D., Tuo, J., Wu, C., Zhang, M., Su, L., 2020. Comparison of pore evolution for a Mesoproterozoic marine shale and a Triassic terrestrial mudstone during artificial maturation experiments. Journal of Natural Gas Science and Engineering 75, 103153. pyrolysis experiments were performed on a Mesoproterozoic Hongshuizhuang marine shale sample and a Triassic Chang 7 terrestrial mudstone sample, in order to understand the mechanisms of pore evolution in shales with similar organic geochemical characteristics in different depositional environments. The pore characteristics of the solid samples from the thermal maturation experiments were investigated by low-pressure gas (N2 and CO2) sorption isotherms tests and Field Emission - Scattering Electron Microscopy (FE-SEM) imaging. Results indicate the marine shale samples develop more micropores than that of the terrestrial mudstone samples during the artificial maturation. Secondary organic pores are observed in the unheated samples (~0.76% EqRo) for the marine shale, which is earlier than that of in the terrestrial mudstone (observed in the sample at 250?°C, ~0.8% Ro). Significant development of organic pores at 350?°C for both the two shales. And the transformation of smaller pores into larger pores takes place at 450?°C for the marine shale, as well as for the terrestrial mudstone. In highly overmatured shales, the overpressure formed by organic matter cracking to gas can make surrounding interparticle space to vanish. The high content of rigid minerals in the marine shale is more conducive to the preservation of organic pores than the terrestrial mudstone with rich in ductile clay minerals. Therefore, pore increases continuously for the marine shale but decreases for the terrestrial mudstone after 500?°C. Micropores would be generated if a high lithostatic pressure exists under experimental conditions, which may be largely responsible for the disagreement of pore evolution of similar shales in other publications. Finally, a conceptual model of pore evolution for type-II marine and terrestrial shales is proposed. The study reveals that the pore evolution of shales with different sedimentary environments is divergent, and this need to be separately considered in the future work.Song, L., Carr, T.R., 2020. The pore structural evolution of the Marcellus and Mahantango shales, Appalachian Basin. Marine and Petroleum Geology 114, 104226. generation and primary migration of hydrocarbons in organic-rich shale leaves void space in organic matter, which is the porosity associated with organic matter commonly observed under scanning electron microscope (SEM). In this study, Middle Devonian black shale core samples were collected from three wells penetrating the organic-rich Marcellus Shale and the organic-lean Mahantango Formation in Pennsylvania and West Virginia. Pyrolysis, ion milled SEM and low-pressure nitrogen adsorption analysis were conducted to investigate the organic richness and the properties of the pore system. Vitrinite reflectance (Ro) values in the range of 1.36%–2.89% represent a maturity spectrum covering the wet-gas to post-mature zones. In general, the pore system is composed of organic matter-hosted pores and mineral-hosted pores. However, the dominant pore types and pore sizes vary stratigraphically across lithology and abundance of organic matter. All the organic matter observed in this study shows an amorphous occurrence. Pore space between mineral grains (both silt-size and clay-size) can be filled by organic matter, which contains secondary porosity generated by thermal cracking of kerogen. Mineral-hosted pores are concentrated in organic-lean samples in which secondary organic matter could not fill most of the primary pore space. The destruction of primary mineral-hosted pores and the generation of secondary organic matter-hosted pores were observed. TOC values show positive correlations with the porosity, specific surface area, and the abundance of micropores. Increasing thermal maturity correlates with a significant decrease of pore volume and surface area, primarily through diminishing or vanishing of micropores. The richness and thermal maturity of organic matter in organic-rich Devonian shale can be effective parameters for evaluation of reservoir quality and upscaling the appraisal.Sorensen, M.J., Miller, K.E., Jorgenson, J.W., Kennedy, R.T., 2020. Ultrahigh-Performance capillary liquid chromatography-mass spectrometry at 35?kpsi for separation of lipids. Journal of Chromatography A 1611, 460575. in sample preparation, separation, and mass spectrometry continue to expand the coverage in LC-MS based lipidomics. While longer columns packed with smaller particles in theory give higher separation performance compared to shorter columns, the implementation of this technology above commercial limits has been sparse due to difficulties in packing long columns and successfully operating instruments at ultrahigh pressures. In this work, a liquid chromatograph that operates up to 35?kpsi was investigated for the separation and identification of lipid species from human plasma. Capillary columns between 15–50?cm long were packed with 1.7??m BEH C18 particles and evaluated for their ability to separate lipid isomers and complex lipid extracts from human plasma. Putative lipid class identifications were assigned using accurate mass and relative retention time data of the eluting peaks. Our findings indicate that longer columns packed and operated at 35?kpsi outperform shorter columns packed and run at lower pressures in terms of peak capacity and numbers of features identified. Packing columns with relatively high concentration slurries (200?mg/mL) while sonicating the column resulted in 6–34% increase in peak capacity for 50?cm columns compared to lower slurry concentrations and no sonication. For a given analysis time, 50?cm long columns operated at 35?kpsi provided a 20–95% increase in chromatographic peak capacity compared with 15?cm columns operated at 15?kpsi. Analysis times up to 4?h were evaluated, generating peak capacities up to 410?±?5 (n?=?3, measured at 4σ) and identifying 480?±?85 lipids (n?=?2). Importantly, the results also show a correlation between the peak capacity and the number of lipids identified from a human plasma extract. This correlation indicates that ionization suppression is a limiting factor in obtaining sufficient signal for identification by mass spectrometry. The result also shows that the higher resolution obtained by shallow gradients overcomes possible signal reduction due to broader, more dilute peaks in long gradients for improving detection of lipids in LC-MS. Lastly, longer columns operated at shallow gradients allowed for the best separation of both regional and geometrical isomers. These results demonstrate a system that enables the advantages of using longer columns packed and run at ultrahigh pressure for improving lipid separations and lipidome coverage.Sosa-Montes de Oca, C., de Lange, G.J., Martínez-Ruiz, F., Ortega-Huertas, M., Rodríguez-Tovar, F.J., 2020. Microscale trace-element distribution across the Cretaceous/Palaeogene ejecta layer at the Agost section: Constraining the recovery of pre-impact conditions. Chemical Geology 533, 119431. high-resolution, sub-mm scale analysis of the distribution of major and trace elements across the ejecta layer marking the Cretaceous/Palaeogene boundary (KPgB) at the Agost section (SE Spain) was performed using Laser Ablation-Inductivity Coupled Plasma-Mass Spectrometry (LA-ICP-MS). A KPgB interval ≈17?mm thick, has been selected for this study. It includes gray calcareous marl from the uppermost Maastrichtian (Cretaceous), 2.02-mm-thick red clay (the ejecta layer), and blackish-gray clay (boundary clay layer) from the lowermost Danian (Palaeogene). The unconsolidated sediments were resin-embedded under O2-free conditions and analyzed by LA-ICP-MS line continuous scan measurements at 20?μm increments and a laser-beam of 120?μm. These micron-scale analyses show that the anomalous contents of trace and major elements in this boundary are restricted to the ejecta layer, which displays a relatively uniform distribution over its ≈2?mm thickness. Trace and major elemental ratios, such as Ca/Al, Ti/Al, Cr/Al, Fe/Al, Ni/Al, Cu/Al, Zn/Al, As/Al, Sb/Al and Pb/Al have similar values below and above the ejecta layer, consistent with similar palaeoenvironmental conditions prior to and after the impact event. Such element distribution points to anomalies exclusively restricted to the ejecta, thus a nearly instantaneous re-establishment of pre-impact conditions right after the impact event is observed.Sosdian, S.M., Babila, T.L., Greenop, R., Foster, G.L., Lear, C.H., 2020. Ocean carbon storage across the middle Miocene: a new interpretation for the Monterey Event. Nature Communications 11, 134. Miocene Climatic Optimum (MCO, 14–17?Ma) was ~3–4?°C warmer than present, similar to estimates for 2100. Coincident with the MCO is the Monterey positive carbon isotope (δ13C) excursion, with oceans more depleted in 12C relative to 13C than any time in the past 50?Myrs. The long-standing Monterey Hypothesis uses this excursion to invoke massive marine organic carbon burial and draw-down of atmospheric CO2 as a cause for the subsequent Miocene Climate Transition and Antarctic glaciation. However, this hypothesis cannot explain the multi-Myr lag between the δ13C excursion and global cooling. We use planktic foraminiferal B/Ca, δ11B, δ13C, and Mg/Ca to reconstruct surface ocean carbonate chemistry and temperature. We propose that the MCO was associated with elevated oceanic dissolved inorganic carbon caused by volcanic degassing, global warming, and sea-level rise. A key negative feedback of this warm climate was the organic carbon burial on drowned continental shelves.So?nicka, M., Lüders, V., 2020. Fluid inclusion evidence for low-temperature thermochemical sulfate reduction (TSR) of dry coal gas in Upper Permian carbonate reservoirs (Zechstein, Ca2) in the North German Basin. Chemical Geology 534, 119453. Permian Zechstein carbonate Ca2 gas reservoirs in the southern part of the Pompeckj Block in the North German Basin locally contain up to 36?vol% hydrogen sulfide (H2S) produced by thermochemical sulfate reduction (TSR). TSR was triggered by migration of dry to extremely dry coal gas from Upper Carboniferous into the Zechstein carbonate reservoirs. Methane reacted with dissolved sulfate at temperatures of <150?°C, as inferred from fluid inclusions hosted in fracture-filling minerals and cements in the carbonate reservoir rocks. Such low temperatures for methane-dominated TSR are unique and were not observed so far, as it was widely believed that alteration of super dry methane requires much higher temperatures. Here we present detailed compositional and carbon isotope data of reservoir gases as well as those of gases trapped in fluid inclusions hosted in cements and fracture-filling minerals in Zechstein Ca2 carbonate reservoir rocks. We constrained the P-T conditions of gas entrapment, hydrocarbon reactivity and the lower temperature limit for TSR.The results of this study decipher three major stages of gas migration in the Pompeckj Block. Stage I commenced in the Late Triassic during burial when Zechstein Ca2 reservoirs were charged with dry CH4-CO2?±?N2 gas sourced from mature Upper Carboniferous coals. Burial continued through the Jurassic and caused alteration of Ca2 reservoir gas by sulfate reduction reactions due to increasing temperatures. Entrapment of CH4-H2S-CO2-N2 gases in fluid inclusions, hosted in cements and fracture-filling minerals, occurred at temperatures between 100 and 152?°C and was related to Stage II uplift in the Early Lower Cretaceous. In the Late Cretaceous (Stage III) deep burial of the Pompeckj Block led to charge of the Zechstein Ca2 carbonate reservoirs with Upper Carboniferous-derived CH4-CO2?±?N2?±?C2+ coal gas and/or dilution of existing reservoir gas at temperatures of 144–167?°C. Highly variable δ13CCH4 values from ?18.7 to ?8.7‰ and very negative δ13CCO2 values (?22.4 to ?18.9‰) of H2S-rich fluid inclusion gases as well as negative δ13C values (?10.4 to ?4.6‰) of host calcites reveal compelling evidence for participation of methane in TSR. Fluid inclusions imply that CH4-dominated TSR proceeded at Tmin of 135?°C in the presence of catalyzers such as H2S and dissolved Mg2+.This study demonstrates that fluid inclusions serve as an excellent and accurate tool for tracing H2S concentrations in hydrocarbon gases through time and space, which is not possible using the present-day compositions of natural reservoir gases. It also contributes to the understanding of carbonate reservoir-hosted hydrocarbon-bearing fluid systems and processes that significantly control the quality of reservoir gases.Spaak, G., Edwards, D.S., Grosjean, E., Scarlett, A.G., Rollet, N., Grice, K., 2020. Identifying multiple sources of petroleum fluids in Browse Basin accumulations using semi-volatile compounds. Marine and Petroleum Geology 113, 104091. fluid correlation studies often rely on compounds that are source-specific, but only represent a minor fraction of the bulk fluid (e.g. steranes). The correlation in the present study utilises compounds that represent a significant proportion of the bulk fluid (semi-volatile aromatics (SVA)) and diamondoids. Comprehensive two dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC?×?GC-TOFMS) was used to analyse diamondoids and SVA in whole oil/condensate samples from the Browse Basin, North West Shelf, Australia. Together with aromatic maturity ratios and the stable carbon isotopic composition for selected diamondoids and alkylbenzenes, these analyses demonstrate that numerous accumulations within the Browse Basin contain hydrocarbons from mixed sources. The diamondoid and SVA data provides further information on the current hydrocarbon fluid discrimination, which is primarily based on saturated biomarker compositions. Results of this study reveal a complex fill history by identifying the presence of a high maturity fluid(s) in the biodegraded accumulations on the Yampi Shelf, i.e. in the greater Cornea field and at Gwydion-1. This high maturity fluid is most likely derived from the Lower–Middle Jurassic Plover Formation (J10–J20 supersequences) in the greater Cornea area and, in the case of Gwydion-1, additional hydrocarbons may also be derived from the Upper Jurassic Vulcan Formation (J30–K10 supersequences). Other accumulations that comprise mixtures include Mimia-1 and Concerto-1 ST1 Deep, located to the north of the Ichthys field, and could represent charge from several Jurassic source rocks. The most mature fluids analysed in this basin are family II Plover-sourced and reservoired condensates from Kronos-1, Dinichthys North-1 and Gorgonichthys-1, as demonstrated by their elevated concentrations of the methyladamantanes and methyldiamantanes. The Dinichthys North-1 and Gorgonichthys-1 condensates also show a significant enrichment in the δ13C compound-specific values of the di-, tri- and tetra-methylbenzenes, whereas the Kronos-1 condensate does not, suggesting derivation from different source kitchens.Sparkes, R.B., Hovius, N., Galy, A., Liu, J.T., 2020. Survival of graphitized petrogenic organic carbon through multiple erosional cycles. Earth and Planetary Science Letters 531, 115992. forms the endpoint for organic carbon metamorphism; it is extremely resilient to physical, biological and chemical degradation. Carbonaceous materials (CM) contained within sediments, collected across Taiwan and from the Gaoping submarine canyon, were analyzed using Raman spectroscopy to determine the crystallinity. This allowed the erosional and orogenic movements of petrogenic organic carbon (OCpetro) during the Taiwanese orogeny to be deduced. After automatically fitting and classifying spectra, the distribution of four groups of CM within the sediments provides evidence that many forms of OCpetro have survived at least one previous cycle of erosion, transport and burial before forming rocks in the Western Foothills of the island. There is extensive detrital graphite present in rocks that have not experienced high-grade metamorphism, and graphite flakes are also found in recently deposited marine sediments off Taiwan. The tectonic and geological history of the island shows that these graphite flakes must have survived at least three episodes of recycling. Therefore, transformation to graphite during burial and orogeny is a mechanism for stabilizing organic carbon over geological time, removing biospheric carbon from the active carbon cycle and protecting it from oxidation during future erosion events.Spieck, E., Spohn, M., Wendt, K., Bock, E., Shively, J., Frank, J., Indenbirken, D., Alawi, M., Lücker, S., Hüpeden, J., 2020. Extremophilic nitrite-oxidizing Chloroflexi from Yellowstone hot springs. The ISME Journal 14, 364-379. microorganisms occur across a wide temperature range from 4 to 84?°C and previous studies in geothermal systems revealed their activity under extreme conditions. Archaea were detected to be responsible for the first step of nitrification, but it is still a challenging issue to clarify the identity of heat-tolerant nitrite oxidizers. In a long-term cultivation approach, we inoculated mineral media containing ammonium and nitrite as substrates with biofilms and sediments of two hot springs in Yellowstone National Park (USA). The nitrifying consortia obtained at 70?°C consisted mostly of novel Chloroflexi as revealed by metagenomic sequencing. Among these, two deep-branching novel Chloroflexi were identified as putative nitrite-oxidizing bacteria (NOB) by the presence of nitrite oxidoreductase encoding genes in their genomes. Stoichiometric oxidation of nitrite to nitrate occurred under lithoautotrophic conditions, but was stimulated by organic matter. Both NOB candidates survived long periods of starvation and the more abundant one formed miniaturized cells and was heat resistant. This detection of novel thermophilic NOB exemplifies our still incomplete knowledge of nitrification, and indicates that nitrite oxidation might be an ancient and wide-spread form of energy conservation.Sproul, G.D., 2019. Membranes composed of lipopeptides and liponucleobases inspired protolife evolution. Origins of Life and Evolution of Biospheres 49, 241-254. acids and peptides have been demonstrated to form lipoamino acids and lipopeptides under presumed prebiotic conditions, and readily form liposomes. Of the common nucleobases, adenine forms a liponucleobase even below 100?°C. Adenine as well as other nucleobases can also be derivatized with ethylene carbonate (and likely other similar compounds) onto which fatty acids can be attached. The fatty acid tails along with appropriately functionalized nucleobases provide some solubility of liponucleobases in membranes. Such membranes would provide a structure in which three of biology’s major components are closely associated and available for chemical interactions. Nucleobase-to-nucleobase interactions would ensure that the liponucleobases would have a uniquely different head-group relationship than other amphiphiles within a membrane, likely forming rafts due their π-π interactions and providing surface discontinuities that could serve as catalytic sites. The π-π bond distance in aromatic compounds is typically 0.34?nm, commensurate with that of the amine to carboxylate distance in alpha amino acids. This would have provided opportunity for hydrogen bonding between amino acids and the distal primary amines or tautomeric carbonyl/hydroxyl groups of two π-bonded nucleobases. Such bonding would weaken the covalent linkages within the amino acids, making them susceptible to forming peptide bonds with an adjacent amino acid, likely a lipoamino acid or lipopeptide. Were this second lipoamino acid bound to a third π-bonded nucleobase, it could result in orientation, destabilization and peptide formation. The stacked triplet of nucleobases might constitute the primordial codon triplet from which peptides were synthesized: primordial translation.Stacey, R.J., Dunne, J., Brunning, S., Devièse, T., Mortimer, R., Ladd, S., Parfitt, K., Evershed, R., Bull, I., 2020. Birch bark tar in early Medieval England – Continuity of tradition or technological revival? Journal of Archaeological Science: Reports 29, 102118. bark tar is a manufactured product with a history of production and use that reaches back to the Palaeolithic. Its sticky, water resistant and biocidal properties mean that it has a wide range of applications, for example, as a multipurpose adhesive, sealant and in medicine. Archaeological evidence for birch bark tar in the old world covers a broad geographic range from the UK to the Baltic and from the Mediterranean to Scandinavia. In the east and north of this range there is continuity of use to modern times but in western Europe and the British Isles the use of birch bark tar has generally been viewed as limited to prehistory, with gradual displacement by pine tars during the Roman period.Here, we report new finds of birch bark tar from two early Medieval sites in the east of England. Analysis by HT-GC/MS to identify the tars also revealed fatty material, possibly added to modify the tar. The different contexts of the finds point to diverse applications of the material: in one case perhaps a medicine, the other associated with a ceramic container, possibly used for processing the tar. The results present the first identification of birch bark tar from early Medieval archaeological contexts in the UK. Together they indicate a later period of use for birch bark tar in the UK than has been previously observed and raise the question of whether this indicates evidence of a longer continuity of use than hitherto recognised or a later reintroduction of the technology in the Medieval period, in which case the similarities between the find sites, both early Anglo-Saxon cemeteries with comparable assemblages of grave goods, may be significant.Stevenson, D.S., 2020. Phytoclimatic mapping of exoplanets. International Journal of Astrobiology 19, 68-77. concept of exoplanetary habitability is evolving. The driving force is a desire to define the biological potential of planets and identify which can host complex and possibly intelligent life. To assess this in a meaningful manner, climate models need to be applied to realistic surfaces. However, the vast majority of climate models are developed using generic aquaplanet, or swamp planet, scenarios that provide uniform, surface frictional coefficients. However, aside from planets with largely uniform oceans, these models are not obviously useful when it comes to understanding the impact of climate on biodiversity. Here, we show that contrary to expectation, the aquaplanet models can be directly applied to planets with a variety of land areas, with little need for modification. Using this premise, this paper provides a simple mathematical framework that may be applied to more complex planetary surfaces and identifies the majority of the climate-model components that are needed to accurately determine the biological potential of habitable exoplanets. As a proof-of-concept, an available climate model for Proxima b is used to determine its biological potential, given a suitable atmosphere.Stewart, T.A., Lemberg, J.B., Taft, N.K., Yoo, I., Daeschler, E.B., Shubin, N.H., 2020. Fin ray patterns at the fin-to-limb transition. Proceedings of the National Academy of Sciences 117, 1612-1620.: To explain how limbs evolved from fins, paleontologists have traditionally studied the endoskeleton. Here, we provide a comparative analysis of the other skeletal system of fins, the dermal skeleton. We describe dermal ray anatomy for 3 species of tetrapodomorph fishes. These data show that, prior to the origin of digits, dermal rays were simplified, the fin web became reduced in size, and the top and bottom of the fin became more asymmetric. These changes reveal how fins became adapted for interacting with the substrate prior to the fin-to-limb transition and that dorsoventral asymmetry is an important, understudied axis of diversification in paired fins.Abstract: The fin-to-limb transition was marked by the origin of digits and the loss of dermal fin rays. Paleontological research into this transformation has focused on the evolution of the endoskeleton, with little attention paid to fin ray structure and function. To address this knowledge gap, we study the dermal rays of the pectoral fins of 3 key tetrapodomorph taxa—Sauripterus taylori (Rhizodontida), Eusthenopteron foordi (Tristichopteridae), and Tiktaalik roseae (Elpistostegalia)—using computed tomography. These data show several trends in the lineage leading to digited forms, including the consolidation of fin rays (e.g., reduced segmentation and branching), reduction of the fin web, and unexpectedly, the evolution of asymmetry between dorsal and ventral hemitrichia. In Eusthenopteron, dorsal rays cover the preaxial endoskeleton slightly more than ventral rays. In Tiktaalik, dorsal rays fully cover the third and fourth mesomeres, while ventral rays are restricted distal to these elements, suggesting the presence of ventralized musculature at the fin tip analogous to a fleshy “palm.” Asymmetry is also observed in cross-sectional areas of dorsal and ventral rays. Eusthenopteron dorsal rays are slightly larger than ventral rays; by contrast, Tiktaalik dorsal rays can be several times larger than ventral rays, and degree of asymmetry appears to be greater at larger sizes. Analysis of extant osteichthyans suggests that cross-sectional asymmetry in the dermal rays of paired fins is plesiomorphic to crown group osteichthyans. The evolution of dermal rays in crownward stem tetrapods reflects adaptation for a fin-supported elevated posture and resistance to substrate-based loading prior to the origin of digits.Striolo, A., 2019. Clathrate hydrates: recent advances on CH4 and CO2 hydrates, and possible new frontiers. Molecular Physics 117, 3556-3568.. 1646436Gas hydrates continue to attract enormous attention throughout the energy industry, as both a hindrance in conventional production and a substantial unconventional resource. Scientists continue to be fascinated by the hydrates’ ability of sequestering large amounts of hydrophobic gases, unusual thermal transport properties and unique molecular structures. Technologically, clathrate hydrates promise advantages in applications as diverse as carbon sequestration and water desalination. The communities interested in hydrates span traditional academic disciplines, including earth science, physical chemistry and petroleum engineering. The studies on this field are equally diverse, including field expeditions to attempt the production of natural gas from hydrate deposits accumulated naturally on the seafloor, to lab-scale studies to exchange CO2 for CH4 in hydrates; from theoretical studies to understand the stability of hydrates depending on the guest molecules, to molecular simulations probing nucleation mechanisms. This review highlights a few fundamental questions, with focus on knowledge gaps representing some of the barriers that must be addressed to enable growth in the practical applications of hydrate technology, including natural gas storage, water desalination, CO2 – CH4 exchange in hydrate deposits and prevention of hydrate plugs in conventional energy transportation.Su, C., Zhang, M., Lin, L., Yu, G., Zhong, H., Chong, Y., 2020. Reduction of iron oxides and microbial community composition in iron-rich soils with different organic carbon as electron donors. International Biodeterioration & Biodegradation 148, 104881. order to indicate the effect of carbon sources on the composition of dissimilatory iron reducing bacteria (DIRB) and the reduction characteristics of iron oxides in the soils, different carbon sources (glucose, starch, acetate, and plant biomass) were selected and mixed with red soil for anaerobic conservation. During the process, COD, Fe (Ⅱ), and pH were monitored, and the composition of the microbial community was analyzed. The results show that the amount of reducible ferric iron in red soils differed depending on the carbon source. For example, the amount of reducible ferric iron in the plant biomass system was much higher than in the other three. High throughput sequencing results showed that each system had 1–2 dominant species (operational taxonomy units) with relative abundance (>12%) much higher than others. The predominant DIRB in the glucose, starch, and acetic acid systems were the same as found in previous studies. They were Clostridium species in both glucose and starch systems, and was Geobacter in acetic acid systems. However, the dominant species in the plant biomass system, those belonging to Ignavibacteriaceae, are seldom reported DIRB. Although species from the family were reported to have iron reduction ability, they have never been identified as a dominant group in the iron reduction process before.Sun, P., Cai, C., Tang, Y., Tao, Z., Zhao, W., 2020. A new approach to investigate effects of biodegradation on pyrrolic compounds by using a modified Manco scale. Fuel 265, 116937. of pyrrolic compounds which are not in the Peters and Moldowan’s scale (PM level) has been rarely reported. A suite of oil samples produced from the Neogene Guantao (Ng) Formation in the Bohai Bay Basin were analyzed. They have similar maturity and were derived from similar parent organic matter. The oil samples were assorted into different biodegradation degrees by using modified Manco Number 2 (MN2). Carbazole, methylcarbazole and dimethylcarbazole are found to have been biodegraded, resulting in the decrease in their absolute concentrations with increasing MN2. Alkylcarbazoles are found to be more susceptible to biodegradation than benzocarbazoles, among which, benzo[b]carbazole is the most resistant and 3-methylcarbazole is more resistant than other methylcarbazoles, thus both benzocarbazoles/total carbazoles and 3-methylcarbazole/total methylcarbazoles ratios rise with MN2 values. The bio-resistant sequence of dimethylcarbazole(DMC) is N–H[C1]semi-shielded?>?exposed?>?shielded isomers. Compared to the PM level, the Manco scale is more suitable to evaluate the variation patterns of pyrrolic compounds by expressing the level of biodegradation quantitatively with higher resolution than PM level.Sun, Q., Fan, T.W.M., Lane, A.N., Higashi, R.M., 2020. Applications of chromatography-ultra high-resolution MS for stable isotope-resolved metabolomics (SIRM) reconstruction of metabolic networks. TrAC Trends in Analytical Chemistry 123, 115676. is a complex network of compartmentalized and coupled chemical reactions, which often involve transfers of substructures of biomolecules, thus requiring metabolite substructures to be tracked. Stable isotope resolved metabolomics (SIRM) enables pathways reconstruction, even among chemically identical metabolites, by tracking the provenance of stable isotope-labeled substructures using NMR and ultrahigh resolution (UHR) MS. The latter can resolve and count isotopic labels in metabolites and can identify isotopic enrichment in substructures when operated in tandem MS mode. However, MS2 is difficult to implement with chromatography-based UHR-MS due to lengthy MS1 acquisition time that is required to obtain the molecular isotopologue count, which is further exacerbated by the numerous isotopologue source ions to fragment. We review here recent developments in tandem MS applications of SIRM to obtain more detailed information about isotopologue distributions in metabolites and their substructures.Sun, R., Li, Z., Zhao, Z., Yang, H., Wang, X., Zhao, Z., 2020. Characteristics and origin of the Lower Oligocene marine source rocks controlled by terrigenous organic matter supply in the Baiyun Sag, northern South China Sea. Journal of Petroleum Science and Engineering 187, 106821. analyze the dominant factors of the origin of marine source rocks of the northern South China Sea (SCS), this paper focuses on the Lower Oligocene neritic source rocks in the Baiyun Sag of the Pearl River Mouth Basin. This study assesses the source rocks based on the principles and methods of sedimentology, geochemistry, and palynology and data on pyrolysis parameters, biomarker compounds, major and trace elements, and sedimentary organic debris. The paleoproductivity, input of terrigenous organic matter (TOM), redox conditions and sediment flux are characterized by the above parameters. The dominant effects of organic matter (OM) supply, preservation, and dilution on the origin of the source rocks are studied, and a depositional model of the source rocks is established. Finally, the origin of the Lower Oligocene marine source rocks in the northern SCS is clarified. The results show that the main source of the marine source rocks was terrestrial higher plants, while the contribution of planktonic algae was small. The origin of the marine source rocks was strongly controlled by the input of TOM during the depositional period. The source rocks developed in an oxic environment, and the correlation between the redox indices and OM abundance is poor, which indicates that the redox conditions were not the main factor dominating the origin of the source rocks. With an increase in the sediment flux and the barrier formed by low uplifts, the dilution of the OM decreased, and the contact time between OM and oxygen was markedly reduced; therefore, some OM in the oxic bottom water was not oxidized but instead became enriched, thereby forming the source rocks.Sun, R., Li, Z., Zhao, Z., Yang, H., Wang, X., Zhao, Z., 2020. Characteristics and origin of the Lower Oligocene marine source rocks controlled by terrigenous organic matter supply in the Baiyun Sag, northern South China Sea. Journal of Petroleum Science and Engineering 187, 106821. analyze the dominant factors of the origin of marine source rocks of the northern South China Sea (SCS), this paper focuses on the Lower Oligocene neritic source rocks in the Baiyun Sag of the Pearl River Mouth Basin. This study assesses the source rocks based on the principles and methods of sedimentology, geochemistry, and palynology and data on pyrolysis parameters, biomarker compounds, major and trace elements, and sedimentary organic debris. The paleoproductivity, input of terrigenous organic matter (TOM), redox conditions and sediment flux are characterized by the above parameters. The dominant effects of organic matter (OM) supply, preservation, and dilution on the origin of the source rocks are studied, and a depositional model of the source rocks is established. Finally, the origin of the Lower Oligocene marine source rocks in the northern SCS is clarified. The results show that the main source of the marine source rocks was terrestrial higher plants, while the contribution of planktonic algae was small. The origin of the marine source rocks was strongly controlled by the input of TOM during the depositional period. The source rocks developed in an oxic environment, and the correlation between the redox indices and OM abundance is poor, which indicates that the redox conditions were not the main factor dominating the origin of the source rocks. With an increase in the sediment flux and the barrier formed by low uplifts, the dilution of the OM decreased, and the contact time between OM and oxygen was markedly reduced; therefore, some OM in the oxic bottom water was not oxidized but instead became enriched, thereby forming the source rocks.Sun, Y., Gong, S., Li, N., Peckmann, J., Jin, M., Roberts, H.H., Chen, D., Feng, D., 2020. A new approach to discern the hydrocarbon sources (oil vs. methane) of authigenic carbonates forming at marine seeps. Marine and Petroleum Geology 114, 104230. marine hydrocarbon seeps have been discovered in the past three decades, the majority of which are dominated by methane-rich fluids. However, an increasing number of modern oil seeps and a few ancient oil-seep deposits have been recognized in recent years. Oil seepage exerts significant control on the composition of the seep-dwelling fauna and may have impacted the marine carbon cycle through geological time to a greater extent than previously recognized. Yet, distinguishing oil-seep from methane-seep deposits is difficult in cases where δ13Ccarb values are higher than approximately ?30‰ due to mixing of different carbon sources. Here, we present a comparative study of authigenic carbonates from oil-dominated (site GC232) and methane-dominated (site GC852) seep environments of the northern Gulf of Mexico, aiming to determine the geochemical characteristics of the two types of seep carbonates. We analyzed (1) major and trace element compositions of carbonates, (2) total organic carbon (TOC), total nitrogen (TN) and carbon isotope (δ13CTOC) of residue after decalcification, (3) sulfur isotope signatures of chromium reducible sulfur (CRS, δ34SCRS) and residue after CRS extraction (δ34STOS), as well as (4) sulfur contents (TOS) of residue after CRS extraction. Carbonates from the studied oil seep are dominated by aragonite and exhibit lower δ34SCRS values, suggesting carbonate precipitation close to the sediment surface. In addition, oil-seep carbonates are characterized by higher TOC and TOS contents and higher TOC/TN ratios, as well as less negative δ13CTOC values compared to methane-seep carbonates, probably reflecting a contribution of residual crude oil enclosed in oil-seep carbonates. Very low δ13CTOC values (as low as ?68.7‰, VPDB) and low TOC/TN ratios of methane-seep carbonates indicate that the enclosed organic matter is derived mainly from the biomass of methanotrophic biota. This study presents new geochemical data that will allow the discrimination of oil-seep from methane-seep deposits. Although some of the geochemical patterns are likely to be affected by late diagenesis, if applied with caution, such patterns can be used to discern the two end-member types of seepage – oil seeps and methane seeps – in the geological record.?upraha, L., Henderiks, J., 2020. A 15 million-year long record of phenotypic evolution in the heavily calcified coccolithophore Helicosphaera and its biogeochemical implications. Biogeosciences Discussions 2020, 1-26. biogeochemical performance of coccolithophores is defined by their overall abundance in the oceans, but also by a wide range in cell size, degree of calcification and carbon production rates between different species. Species’ sensitivity to environmental forcing has been suggested to relate to their cellular PIC?:?POC ratio and other physiological constraints. Understanding both the short and longer-term adaptive strategies of different coccolithophore lineages, and how these in turn shape the biogeochemical role of the group, is therefore crucial for modeling the ongoing changes in the global carbon cycle. Here we present data on the phenotypic evolution of a large and heavily-calcified genus Helicosphaera (order Zygodiscales) over the past 15 million years (Ma), at two deep-sea drill sites from the tropical Indian Ocean and temperate South Atlantic. The modern species Helicosphaera carteri, which displays eco-physiological adaptations in modern strains, was used to benchmark the use of its coccolith morphology as a physiological proxy in the fossil record.Our results show that, on the single-genotype level, coccolith morphology has no correlation with physiological traits in H. carteri. However, significant correlations of coccolith morphometric parameters with cell size and physiological rates do emerge once multiple genotypes or closely related lineages are pooled together. Using this insight, we interpret the phenotypic evolution in Helicosphaera as a global, resource limitation-driven selection for smaller cells, which appears to be a common adaptive trait among different coccolithophore lineages, from the warm and high-CO2 world of the middle Miocene to the cooler and low-CO2 conditions of the Pleistocene. However, despite a significant decrease in mean size, Helicosphaera kept relatively stable PIC?:?POC (as inferred from the coccolith aspect ratio) and thus highly conservative biogeochemical output on the cellular level. We argue that this supports its status as an obligate calcifier, like other large and heavily-calcified genera such as Calcidiscus and Coccolithus, and that other adaptive strategies, beyond size-adaptation, must support the persistent, albeit less abundant, occurrence of these taxa. This is in stark contrast with the ancestral lineage of Emiliania and Gephyrocapsa, which not only decreased in mean size but also displayed much higher phenotypic plasticity in degree of calcification while becoming globally more dominant in plankton communities.Taenzer, L., Carini, P.C., Masterson, A.M., Bourque, B., Gaube, J.H., Leavitt, W.D., 2020. Microbial methane from methylphosphonate isotopically records source. Geophysical Research Letters 47, e2019GL085872.: Methane is a potent greenhouse gas commonly supersaturated in the oxic surfaces waters of oceans and lakes, yet canonical microbial methanogens are obligate anaerobes. One proposed methane production pathway involves microbial degradation of methylphosphonate (MPn), which can proceed in the presence of oxygen. Directly tracing dissolved methane to its source in oxic waters, however, remains a challenge. To address this knowledge gap, we quantified the carbon isotopic fractionation between substrate MPn and product methane (1.3‰) in lab experiments, which was 1 to 2 orders of magnitude smaller than canonical pathways of microbial methanogenesis (20 to 100‰). Together, these results indicated that microbial catabolism of MPn is a source of methane in surface oceans and lake waters, but to differentiate sources of MPn in nature a further accounting of all sources is necessary. Methane from this pathway must be considered in constraining the marine carbon cycle and methane budget.Plain Language Summary: Each year microbes in the surface of lakes and oceans capture gigatons of carbon dioxide from the atmosphere. Some of this organic carbon is converted to the potent greenhouse gas methane right there in the surface waters, where it may easily escape to the atmosphere. Precisely how much methane is released from one specific microbial pathway that is intimately involved in the cycling of both carbon and phosphorus remains an outstanding question. To enable environmental geoscientists to track this process, we establish isotopic “fingerprint” of this process in the laboratory. Using these lab‐derived constraints, we reinterpreted the limited available C‐isotopic data from methane dissolved in oxygenated ocean and lake waters.Takeya, M., Ubaidah, A., Shimokawara, M., Okano, H., Nawa, T., Elakneswaran, Y., 2020. Crude oil/brine/rock interface in low salinity waterflooding: Experiments, triple-layer surface complexation model, and DLVO theory. Journal of Petroleum Science and Engineering 188, 106913. determination of the electrokinetic properties of crude oil/brine and rock/brine interfaces is necessary to understand and evaluate the low salinity waterflooding (LSWF) effect on wettability alteration and enhanced oil recovery (EOR). The interface properties and characteristics of oil and rock minerals significantly affect LSWF and must be elucidated in detail. Herein, the interaction of crude oil, brine, and rock was studied to elucidate the LSWF effect in carbonate and sandstone reservoirs. A triple-layer surface complexation model was proposed to describe the calcite/brine and kaolinite/brine interfaces and was verified with zeta potential experiments at various pH and calcium, magnesium, and sulphate concentrations. Furthermore, the surface complexation model prediction of zeta potential agreed well with the measured data for the suspension in seawater, formation water, and associated dilutions. The predicted surface potential of crude oil, calcite, and kaolinite was used in Derjaguin-Landau-Verwey-Overbeek (DLVO) theory to estimate the total disjoining pressure as attractive/repulsive forces. The interaction between crude oil and calcite/kaolinite on seawater dilution and in the presence of sulphate in the diluted solution for calcite was evaluated via disjoining pressure. Moreover, the importance of electrokinetic properties on attractive/repulsive forces and the mechanisms for wettability alteration in crude oil-brine-kaolinite due to LSWF as well as in oil-brine-calcite because of sulphate addition are discussed.Taleb, F., Lemaire, M., Garziglia, S., Marsset, T., Sultan, N., 2020. Seafloor depressions on the Nigerian margin: Seabed morphology and sub-seabed hydrate distribution. Marine and Petroleum Geology 114, 104175. hydrate quantification using acoustic data requires proper knowledge of the mineralogy of their host sediment. In this paper, a petrophysical model allowing GH quantification at sites where mineralogy profiles are absent is proposed. This approach is applied to a high gas flux pockmark system in the Gulf of Guinea where in-situ acoustic and geotechnical measurements together with core measurements could have been correlated and tied to seismic data. Projections of the in-situ measurements on seismic profiles have shown that the study area not only accommodates zones of shallow and dense GH; but also zones where solid hydrate and free gas coexist as well as pockets of free gas. Further analysis of several seismic profiles has allowed illustrating the detailed GH occurrence zone within the study area, estimate its volume and its occupancy ratio of the pockmark. Correlations between GH content and 3D bathymetry sections have allowed to draw a link between different GH contents and the morphology of the pockmark, which also shares similarities with the morphology of the GH occurrence zone it accommodates.Tan, J., Sephton, M.A., 2019. Organic records of early life on Mars: The role of iron, burial, and kinetics on preservation. Astrobiology 20, 53-72. that are likely to contain evidence of past life on Mars must have been deposited when and where environments exhibited habitable conditions. Mars analog sites provide the opportunity to study how life could have exploited such habitable conditions. Acidic iron- and sulfur-rich streams are good geochemical analogues for the late Noachian and early Hesperian, periods of martian history where habitable conditions were widespread. Past life on Mars would have left behind fossilized microbial organic remains. These are often-sought diagnostic evidence, but they must be shielded from the harsh radiation flux at the martian surface and its deleterious effect on organic matter. One mechanism that promotes such preservation is burial, which raises questions about how organic biomarkers are influenced by the postburial effects of diagenesis. We investigated the kinetics of organic degradation in the subsurface of Mars. Natural mixtures of acidic iron- and sulfur-rich stream sediments and their associated microbial populations and remains were subjected to hydrous pyrolysis, which simulated the increased temperatures and pressures of burial alongside any promoted organic/mineral interactions. Calculations were made to extrapolate the observed changes over martian history. Our experiments indicate that low carbon contents, high water-to-rock ratios, and the presence of iron-rich minerals combine to provide unfavorable conditions for the preservation of soluble organic matter over the billions of years necessary to produce present-day organic records of late Noachian and early Hesperian life on Mars. Successful sample selection strategies must therefore consider the pre-, syn-, and postburial histories of sedimentary records on Mars and the balance between the production of biomass and the long-term preservation of organic biomarkers over geological time.Tan, N., Contoux, C., Ramstein, G., Sun, Y., Dumas, C., Sepulchre, P., Guo, Z., 2020. Modeling a modern-like pCO2 warm period (Marine Isotope Stage KM5c) with two versions of an Institut Pierre Simon Laplace atmosphere–ocean coupled general circulation model. Climate of the Past 16, 1-16. mid-Piacenzian warm period (3.264 to 3.025?Ma) is the most recent geological period with present-like atmospheric pCO2 and is thus expected to have exhibited a warm climate similar to or warmer than the present day. On the basis of understanding that has been gathered on the climate variability of this interval, a specific interglacial (Marine Isotope Stage KM5c, MIS KM5c; 3.205?Ma) has been selected for the Pliocene Model Intercomparison Project phase 2 (PlioMIP 2). We carried out a series of experiments according to the design of PlioMIP2 with two versions of the Institut Pierre Simon Laplace (IPSL) atmosphere–ocean coupled general circulation model (AOGCM): IPSL-CM5A and IPSL-CM5A2. Compared to the PlioMIP 1 experiment, run with IPSL-CM5A, our results show that the simulated MIS KM5c climate presents enhanced warming in mid- to high latitudes, especially over oceanic regions. This warming can be largely attributed to the enhanced Atlantic Meridional Overturning Circulation caused by the high-latitude seaway changes. The sensitivity experiments, conducted with IPSL-CM5A2, show that besides the increased pCO2, both modified orography and reduced ice sheets contribute substantially to mid- to high latitude warming in MIS KM5c. When considering the pCO2 uncertainties (+/? 50?ppmv) during the Pliocene, the response of the modeled mean annual surface air temperature to changes to pCO2 (+/?50 ?ppmv) is not symmetric, which is likely due to the nonlinear response of the cryosphere (snow cover and sea ice extent). By analyzing the Greenland Ice Sheet surface mass balance, we also demonstrate its vulnerability under both MIS KM5c and modern warm climate.Tanioka, T., Matsumoto, K., 2020. Stability of marine organic matter respiration stoichiometry. Geophysical Research Letters 47, e2019GL085564.: The amount of oxygen consumed during organic matter remineralization critically depends on how much organic carbon is remineralized per unit dissolved oxygen respired (respiratory quotient, RQ) but the global distribution and the mechanisms that control RQ are not well understood. Here we estimate RQ in the surface ocean by using two independent methods, one using satellite‐derived macromolecular composition of phytoplankton and another using objectively gridded nutrient data. Both methods yield mean RQ of ~0.7 with small spatial variability consistent with previous estimates. This pattern is likely to be a result of phytoplankton protein content universally exceeding those of carbohydrates and lipids. At face value, the relative stability of RQ suggests that the remineralization stoichiometry will not affect the ongoing deoxygenation of the world ocean. However, the possibility remains that RQ may increase in the future (e.g., organic matter becoming more carbohydrate‐dominated) and thus ameliorate deoxygenation.Plain Language Summary: Most organic carbon produced by phytoplankton in the surface ocean is decomposed by bacteria using dissolved oxygen. This process is expected to accelerate under global warming leading to a significant loss of oxygen from the marine ecosystem. In order to accurately estimate the total amount of oxygen consumed during the decomposition of organic matter, we require information on how much organic carbon is respired per unit of oxygen consumed (respiratory quotient). Here we estimate respiratory quotient using two independent methods and demonstrate that the estimates agree in showing a nearly uniform value in large parts of the world ocean. We suggest that this is attributable to the fact that globally, the organic matter is largely made of protein which requires more oxygen than other molecules such as lipid and carbohydrate.Tao, H., Qiu, Z., Ji, H., Qiu, J., Allen, M.B., 2020. An integrated approach to understanding the depositional environment and organic matter enrichment factor in Carboniferous source rocks, Junggar Basin, NW China. Geological Journal 55, 31-43. indicators (trace fossils, trace metals, and δ13Corg) are used to assess the depositional environments and controls on organic carbon accumulation in the Lower Carboniferous Nanmingshui Formation, Junggar Basin, NW China. The majority of trace fossils belong to the Nereites ichnofacies, representing low energy, oxygen‐poor, and relatively quiet bottom water environments. However, the shallow water trace fossil Planolites also appears in the strata, possibly reflecting variations in the bottom water oxygen contents of the turbidite succession. Redox proxies Th/U, V/Sc, and V/(V + Ni) reveal variable redox conditions; most of the samples are in the range from suboxic to anoxic depositional conditions. Ni and Cu show a positive correlation with TOC, but U and V have no correlation with TOC, also suggesting the redox conditions were mainly suboxic. The P/Al and Cu/Al ratios of all samples are higher than those of Post‐Archean Australian Shales (PAAS), and about two‐thirds of the samples' Ba/Al and Ni/Al ratios are close to or higher than PAAS, suggesting the Early Carboniferous Junggar Basin had relatively high palaeo‐productivity levels. δ13Corg values average ? 23.75‰, reflecting a mixture of terrestrial organic and marine organic matter. The indexes of Ba/Al, Cu/Al, Ni/Al, and δ13Corg show good positive correlations with TOC, indicating the palaeo‐productivity played an important role for the organic matter accumulation. On the other hand, the TOC correlates inversely with redox proxies (Th/U, V/Sc, and V/(V + Ni)), suggesting the preservation conditions (anoxia) are not the control factor of organic matters accumulation. Using these multiple approaches, our results indicate that productivity was the primary factor controlling organic matter accumulation.Tarnas, J.D., Mustard, J.F., Lin, H., Goudge, T.A., Amador, E.S., Bramble, M.S., Kremer, C.H., Zhang, X., Itoh, Y., Parente, M., 2019. Orbital identification of hydrated silica in Jezero crater, Mars. Geophysical Research Letters 46, 12771-12782. has the highest demonstrated potential of any phase to preserve microfossils on Earth and therefore may host potential biosignatures on Mars. We detected hydrated silica in Jezero crater, the landing site of NASA's Mars 2020 rover mission, by applying Dynamic Aperture Factor Analysis/Target Transformation (DAFA/TT) to images from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). Hydrated silica detections with DAFA/TT were verified using commonly accepted CRISM analysis methods. The morphology of geologic units associated with silica were characterized with high resolution imaging. Several hypotheses are presented for the formation environment of hydrated silica. All are testable via in-situ investigation. We assess the likelihood of silica to preserve biosignatures in these different scenarios based on habitability considerations and biosignature preservation in Earth analog environments and materials. Also reported are possible detections of hydrated silica in the Nili Fossae basement and olivine-rich units, as well as Al-phyllosilicate within Jezero crater.Taylor, R.S., DeMaster, D.J., Burdige, D.J., 2020. Assessing the distribution of labile organic carbon from diverse depositional environments on the West Antarctic Peninsula shelf. Deep Sea Research Part I: Oceanographic Research Papers 156, 103166. seabed distributions of labile organic carbon (LOC), i.e., recently produced organic matter from marine plankton, were studied in a variety of depositional environments on the West Antarctic Peninsula continental shelf using the naturally occurring radioisotopes, 14C, 210Pb and 234Th. The effects of bioturbation on the LOC pool were assessed on short-term (seasonal, using 234Thxs within the upper, 2–5 cm) and long-term (decadal, using 210Pbxs from 3-22 cm) timescales to generate LOC degradation coefficients (k) and mean residence times (MRT or τ-LOC) as a function of depth within the sediment column. Based on 234Th distributions, mixing coefficients (Db) ranged from 2 cm2/y to 36 cm2/y, which resulted in LOC MRT values that varied from 0.8y to 9.8y. Based on 210Pb distributions, Db values at depth ranged from 0.2 cm2/y to 1.8 cm2/y, resulting in MRT values that varied from 32y to 4900y. Along the West Antarctic Peninsula, seabed inventories of LOC varied between 17-70 mg/cm2. Bulk LOC becomes less reactive and ages with time during resuspension and transport across the shelf and as LOC is transported deeper within the sediment column by infaunal feeding activities.Teixeira, L.R., Cordas, C.M., Fonseca, M.P., Duke, N.E.C., Pokkuluri, P.R., Salgueiro, C.A., 2020. Modulation of the redox potential and electron/proton transfer mechanisms in the outer membrane cytochrome OmcF from Geobacter sulfurreducens. Frontiers in Microbiology 10, 2941. doi: 10.3389/fmicb.2019. 02941. monoheme outer membrane cytochrome F (OmcF) from Geobacter sulfurreducens plays an important role in Fe(III) reduction and electric current production. The electrochemical characterization of this cytochrome has shown that its redox potential is modulated by the solution pH (redox-Bohr effect) endowing the protein with the necessary properties to couple electron and proton transfer in the physiological range. The analysis of the OmcF structures in the reduced and oxidized states showed that with the exception of the side chain of histidine 47 (His47), all other residues with protonatable side chains are distant from the heme iron and, therefore, are unlikely to affect the redox potential of the protein. The protonatable site at the imidazole ring of His47 is in the close proximity to the heme and, therefore, this residue was suggested as the redox-Bohr center. In the present work, we tested this hypothesis by replacing the His47 with non-protonatable residues (isoleucine – OmcFH47I and phenylalanine – OmcFH47F). The structure of the mutant OmcFH47I was determined by X-ray crystallography to 1.13 ? resolution and showed only minimal changes at the site of the mutation. Both mutants were 15N-labeled and their overall folding was confirmed to be the same as the wild-type by NMR spectroscopy. The pH dependence of the redox potential of the mutants was measured by cyclic voltammetry. Compared to the wild-type protein, the magnitude of the redox-Bohr effect in the mutants was smaller, but not fully abolished, confirming the role of His47 on the pH modulation of OmcF’s redox potential. However, the pH effect on the heme substituents’ NMR chemical shifts suggested that the heme propionate P13 also contributes to the overall redox-Bohr effect in OmcF. In physiological terms, the contribution of two independent acid–base centers to the observed redox-Bohr effect confers OmcF a higher versatility to environmental changes by coupling electron/proton transfer within a wider pH range.Templeton, A.S., Ellison, E.T., 2020. Formation and loss of metastable brucite: does Fe(II)-bearing brucite support microbial activity in serpentinizing ecosystems? Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20180423. rocks undergo successive stages of hydration and oxidation during water/rock interaction, giving rise to secondary minerals such as brucite, serpentine, magnetite and the production of H2(g). Ferroan brucite (Mg x Fe 2+ (1?x) (OH) 2 ) (MgxFe(1?x)2+(OH)2) often forms under low water/rock ratios early during the ‘serpentinization’ process. The formation of ferroan brucite sequesters Fe(II) and suppresses the production of H2, thereby limiting the flux of reductants suitable for sustaining microbial metabolism. Yet ferroan brucite is a relatively soluble mineral ‘reservoir’ for reactive Fe(II). Brucite is often metastable and can be lost at later stages of peridotite hydration when there is a significant increase in the water/rock ratio or the activity of SiO2 or CO2. The Fe(OH)2 component of brucite has the thermodynamic potential to reduce most aqueous oxidants. Therefore, ferroan brucite may reduce water and/or dissolved carbon, nitrogen and sulfur species, while the Fe(II) is converted into more stable secondary minerals such as Fe(II/III)-oxides and hydroxides (e.g. green-rust, magnetite, iowaite and pyroaurite) and ferric serpentine. The reactivity of ferroan brucite, and the associated rate of Fe solubilization and oxidation in subsurface fluids, could be a key regulator on the rate of electron transfer from serpentinites to the rock-hosted biosphere. Aqueous alteration of ferroan brucite may significantly modulate the H2 activity in fluids circulating within partially serpentinized rocks, and buffer H2 as it is lost by advection or in situ consumption by a hydrogenotrophic microbial community. Moreover, there may be microbial organisms that specifically colonize and use ferroan brucite as an electron donor for their metabolism. The energy fluxes sustained by localized brucite oxidation may often be sufficiently large to sustain abundant microbial communities; water/rock reaction zones where brucite is consumed could serve as environments to search for extant or fossil serpentinite-hosted life.Teng, J., Mastalerz, M., Liu, B., Gognat, T., Hauser, E., McLaughlin, P., 2020. Variations of organic matter transformation in response to hydrothermal fluids: Example from the Indiana part of the Illinois Basin. International Journal of Coal Geology 219, 103410. maturation of organic matter in sedimentary rocks is a complex process controlled by multiple parameters. In this study, we examined the thermal history of one location in the Indiana part of the Illinois Basin. A total of 21 samples spanning the time interval from the Ordovician to the Mississippian were selected for maturity assessment and chemical structure characterization of vitrinite/vitrinite-like particles, solid bitumen, and alginite. The reflectance of vitrinite/vitrinite-like particles (VRo) reveals erratic variations with depth from 0.61% to 1.18%. Solid bitumen reflectance (SBRo), ranging from 0.43 to 0.92%, is slightly lower than VRo across this maturity range in this borehole. In addition to documenting reflectance variations with depth, variations within single organic matter particles were analyzed in the Upper Devonian New Albany Shale and Upper Ordovician Maquoketa Shale samples; these samples were targeted because they contained more organic matter than the samples from other stratigraphic units. SBRo shows significant variations within a single solid bitumen particle with a difference up to 0.81%. Significant maturity-related chemical differences within individual particles of solid bitumen and alginite were also revealed using micro-FTIR technique. An increase in temperature with depth of burial is certainly the key factor in controlling the thermal transformation of organic matter in sedimentary rocks. However, it is apparent that this mechanism alone does not explain the stratigraphic variations of VRo throughout the core and reflectance variations within individual solid bitumen and alginite particles. We suggest that the flow of hydrothermal fluids through the New Albany and Maquoketa Shale caused the observed thermal maturity anomaly. High concentrations of chlorine, vanadium, chromium, and zinc also suggest that organic matter transformation was enhanced by the flow of hydrothermal fluids in the study area.Teunissen van Manen, M.L., Jansen, B., Cuesta, F., León-Yánez, S., Gosling, W.D., 2020. From leaf to soil: n-alkane signal preservation, despite degradation along an environmental gradient in the tropical Andes. Biogeosciences Discussions 2020, 1-31. wax n-alkane biomarkers obtained from ancient soils and sediments have been used to reconstruct past environmental changes. However, the interpretation of these ancient n-alkane patterns relies primarily on our understanding of modern plant wax n-alkane patterns measured from leaves. Very little is known about how n-alkane patterns might be altered during the process of transfer from leaves into soil. Therefore our interpretations of the ancient n-alkane biomarker signal could be confounded by an unobserved bias caused by degradation processes. Here we present the n-alkane patterns extracted from leaves, necromass and soil samples to clarify whether the n-alkane pattern, the n-alkane signal, and the local environmental information reflected in the n-alkane signal degrade, as the plant source material degrades in the tropical Andes. We find that the n-alkane patterns do degrade, but that the n-alkane patterns and signal remain similar across sample types. We find that the n-alkane patterns primarily reflect changes in longer vs. shorter n-alkanes, captured by the average chain length (ACL) and the C31?/?(C29?+?C31) ratio (ratio), regardless of sample type. Additionally, soil sample n-alkanes secondarily reflect changes in carbon preference index (CPI) whereas leaf and necromass n-alkanes do not. We find that in all sample types the primary observed n-alkane signals correlate significantly with the environment, temperature in particular, but that soil n-alkane correlations are muted compared to leaf n-alkanes. The secondary n-alkane signal (CPI) in soils also correlates significantly with the environmental signal, temperature in particular. Our results are an important step towards better understanding the taphonomy of the n-alkane signal in the tropics, and suggest that environmental information is preserved in the n-alkane signal, despite the observed degradation.Theulé, P., Endres, C., Hermanns, M., Bossa, J.-B., Potapov, A., 2020. High-resolution gas phase spectroscopy of molecules desorbed from an ice surface: A proof-of-principle study. ACS Earth and Space Chemistry 4, 86-91. gas phase spectroscopy techniques in the microwave, millimeter-wave, and terahertz spectral ranges can be used to study complex organic molecules desorbed from interstellar ice analogue surfaces with a high sensitivity. High-resolution gas phase spectroscopy gives unambiguous information about the molecular composition, the molecular structure, and transition frequencies needed for their detection by radio telescopes in various interstellar and circumstellar environments. The results will be useful not only for interpreting astronomical spectra and understanding astrophysical processes, but also for more general studies of gas-surface chemistry. This paper presents a new experimental approach based on a combination of a chirped-pulse Fourier transform microwave spectrometer detection and a low temperature surface desorption experiment. The experimental set-up is benchmarked on the desorption of ammonia ice detected by high-resolution gas phase microwave spectroscopy.?orsteinsdóttir, G.V., Blischke, A., Sigurbj?rnsdóttir, M.A., ?skarsson, F., Arnarson, ?.S., Magnússon, K.P., Vilhelmsson, O., 2019. Gas seepage pockmark microbiomes suggest the presence of sedimentary coal seams in the ?xarfj?r?ur graben of northeastern Iceland. Canadian Journal of Microbiology 66, 25-38. gas seepage pockmarks are found off- and onshore in the ?xarfj?r?ur graben, Iceland. The bacterial communities of two onshore seepage sites were analysed by 16S rRNA gene amplicon sequencing; the geochemical characteristics, hydrocarbon content, and the carbon isotope composition of the sites were also determined. While one site was found to be characterised by biogenic origin of methane gas, with a carbon isotope ratio (δ13C (‰)) of ?63.2, high contents of organic matter and complex hydrocarbons, the other site showed a mixed origin of the methane gas (δ13C (‰) = ?26.6) with geothermal characteristics and lower organic matter content. While both sites harboured Proteobacteria as the most abundant bacterial phyla, the Deltaproteobacteria were more abundant at the geothermal site and the Alphaproteobacteria at the biogenic site. The Dehalococcoidia class of phylum Chloroflexi was abundant at the geothermal site while the Anaerolineae class was more abundant at the biogenic site. Bacterial strains from the seepage pockmarks were isolated on a variety of selective media targeting bacteria with bioremediation potential. A total of 106 strains were isolated and characterised, including representatives from the phyla Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. This article describes the first microbial study on gas seepage pockmarks in Iceland.Tian, Y., Wan, Y.-Y., Mu, H.-M., Dong, H.-L., Briggs, B.R., Zhang, Z.-H., 2020. Microbial diversity in high-temperature heavy oil reservoirs. Geomicrobiology Journal 37, 59-66. microbial community in oil reservoirs plays important roles in carbon, sulfur, and nitrogen cycling. We identified the microbial composition, abundance, and diversity in two heavy oil wells (W1 and W2) located at Liaohe oilfield, China, that were flooded with higher temperatures, forming a decreasing gradient-temperature field (DGTF) from the steam chamber to the original surrounding formation. The two wells were connected to each other at a depth of 650?m and with temperatures of 249?°C (W1) and 259?°C (W2) in the steam chamber. Water and oil samples were collected from both wells, and 16S rRNA genes were sequenced using Illumina MiSeq (Illumina, San Diego, CA). The number of operational taxonomic units (OTUs) was 5499 and 5938 for W1 and W2, respectively, at 97% clustering. In both wells, the dominant bacterial phylum was Proteobacteria. Euryarchaeota and Crenarchaeota were the only two archaeal phyla detected. Terrimonas and Fluviicola were more abundant in the water sample W1–W, whereas Thermomonas, Nitrosomonas, and Sphingobacterium were more abundant in the oil sample W2-O. Aquificae was the only phylum detected in these wells that had not been detected in other oilfields. Excluding exogenous contamination, the results of this study showed abundant in-situ microbial diversity. The heavy oil reservoir has a large DGTF in higher temperature heavy oil reservoirs, potentially affecting the inner environment.Tomczyk, J., Regulski, P., Lisowska-Gaczorek, A., Szostek, K., 2020. Dental caries and stable isotopes analyses in the reconstruction of diet in Mesolithic (6815–5900 BC) individuals from Northeastern Poland. Journal of Archaeological Science: Reports 29, 102141. aim of this study was to assess carious lesions in Mesolithic individuals from Northeastern Poland and interpret them in the context of the paleo-diet, using physicochemical analyses. The dental material came from two Mesolithic sites in Northeastern Poland, Pierkunowo-Gi?ycko and Wo?na Wie?. The study focused on four individuals from the Mesolithic period (two adults and two children) with a total of 34 teeth (16 deciduous, 18 permanent teeth). The relationship between the results of the dental caries study and the paleo-diet was examined using stable carbon and nitrogen isotopic analysis.Superficial dental caries was found on only five teeth (from three individuals): four permanent and one deciduous molar. In all cases, the dental caries was located on the occlusal surface. The nitrogen isotopic ratios (δ15N) of the individuals were on average 8‰ higher than the values obtained for local herbivorous animals. Increased values of isotopic nitrogen ratios were probably associated with the consumption of organisms from higher trophic levels, such as predatory freshwater fish. It should be noted that the δ15N of fish from the Mesolithic and Neolithic periods (from 12 to 13‰) was similar to that obtained for the studied individuals.It can be concluded that the paleo-diet of the test individuals was probably based largely on freshwater fish. This kind of diet, even with the participation of other cariogenic products, could have significantly slowed down the development of caries in the examined individuals.Toner, J.D., Catling, D.C., 2020. A carbonate-rich lake solution to the phosphate problem of the origin of life. Proceedings of the National Academy of Sciences 117, 883-888.: Phosphate is crucial for the origin of life because it is ubiquitous in key biomolecules. A major issue is that prebiotic syntheses use concentrated phosphate to incorporate phosphate into biomolecules, whereas natural waters are generally phosphate-poor because phosphate reacts with calcium to form low-solubility apatite minerals. Here we show that carbonate-rich lakes can concentrate phosphate to >1 molal levels by locking up calcium in carbonate minerals, which prevents phosphate removal by apatite precipitation. Phosphate-rich lakes may have preferentially formed on the prebiotic Earth because of carbonic acid weathering under CO2-rich atmospheres and the absence of microbial phosphate consumption. This specifically points to an origin of life in carbonate-rich lakes, and so defines aqueous conditions that prebiotic chemists should consider.Abstract: Phosphate is central to the origin of life because it is a key component of nucleotides in genetic molecules, phospholipid cell membranes, and energy transfer molecules such as adenosine triphosphate. To incorporate phosphate into biomolecules, prebiotic experiments commonly use molar phosphate concentrations to overcome phosphate’s poor reactivity with organics in water. However, phosphate is generally limited to micromolar levels in the environment because it precipitates with calcium as low-solubility apatite minerals. This disparity between laboratory conditions and environmental constraints is an enigma known as “the phosphate problem.” Here we show that carbonate-rich lakes are a marked exception to phosphate-poor natural waters. In principle, modern carbonate-rich lakes could accumulate up to ～0.1 molal phosphate under steady-state conditions of evaporation and stream inflow because calcium is sequestered into carbonate minerals. This prevents the loss of dissolved phosphate to apatite precipitation. Even higher phosphate concentrations (>1 molal) can form during evaporation in the absence of inflows. On the prebiotic Earth, carbonate-rich lakes were likely abundant and phosphate-rich relative to the present day because of the lack of microbial phosphate sinks and enhanced chemical weathering of phosphate minerals under relatively CO2-rich atmospheres. Furthermore, the prevailing CO2 conditions would have buffered phosphate-rich brines to moderate pH (pH 6.5 to 9). The accumulation of phosphate and other prebiotic reagents at concentration and pH levels relevant to experimental prebiotic syntheses of key biomolecules is a compelling reason to consider carbonate-rich lakes as plausible settings for the origin of life.Turon, M., Uriz, M.J., 2020. New insights into the archaeal consortium of tropical sponges. Frontiers in Marine Science 6, 789. doi: 10.3389/fmars.2019. 00789. is a poorly studied domain associated with sponges. Many questions that have been addressed for bacteria still remain largely unknown for archaea. In this study, we analyzed the archaeal communities of 17 tropical sponge species from Nha Trang Bay (Vietnam) using archaea specific primers. We recorded patterns of diversity and spatial stability of these microbial communities and compared the results obtained with the bacterial communities, already reported in our previous study. In our study species, Shannon diversity was always lower for archaeal than for bacterial communities. The differences in alpha diversity as well as the presence of indicator phyla reported for the bacterial domain in High Microbial Abundance (HMA) and Low Microbial Abundance (LMA) could not be confirmed for the archaeal communities. Host identity was the main factor structuring the archaeal assemblages. Sponge archaea core was formed by few but very abundant ZOTUs, which contribute with a high proportion to the relative archaea abundance. The inclusion of the obtained sequences into phylogenetic trees allowed finding out whether or not they belonged to the so-called sponge clusters (SC). Our results showed that most of the Thaumarchaeota and Euryarchaeota sequences were more closely related to environmental samples than to SC, suggesting that they might be acquired from the seawater, which need to be verified. However, representatives of Woesarchaeota, which were major members of the archaea microbiome of two sponge species, formed a monophyletic tree, distantly related to any known environmental sequence.Vaks, A., Mason, A.J., Breitenbach, S.F.M., Kononov, A.M., Osinzev, A.V., Rosensaft, M., Borshevsky, A., Gutareva, O.S., Henderson, G.M., 2020. Palaeoclimate evidence of vulnerable permafrost during times of low sea ice. Nature 577, 221-225. change in the Arctic is occurring rapidly, and projections suggest the complete loss of summer sea ice by the middle of this century. The sensitivity of permanently frozen ground (permafrost) in the Northern Hemisphere to warming is less clear, and its long-term trends are harder to monitor than those of sea ice. Here we use palaeoclimate data to show that Siberian permafrost is robust to warming when Arctic sea ice is present, but vulnerable when it is absent. Uranium–lead chronology of carbonate deposits (speleothems) in a Siberian cave located at the southern edge of continuous permafrost reveals periods in which the overlying ground was not permanently frozen. The speleothem record starts 1.5 million years ago (Ma), a time when greater equator-to-pole heat transport led to a warmer Northern Hemisphere. The growth of the speleothems indicates that permafrost at the cave site was absent at that time, becoming more frequent from about 1.35 Ma, as the Northern Hemisphere cooled, and permanent after about 0.4 Ma. This history mirrors that of year-round sea ice in the Arctic Ocean, which was largely absent before about 0.4 Ma, but continuously present since that date. The robustness of permafrost when sea ice is present, as well as the increased permafrost vulnerability when sea ice is absent, can be explained by changes in both heat and moisture transport. Reduced sea ice may contribute to warming of Arctic air, which can lead to warming far inland. Open Arctic waters also increase the source of moisture and increase autumn snowfall over Siberia, insulating the ground from low winter temperatures. These processes explain the relationship between an ice-free Arctic and permafrost thawing before 0.4 Ma. If these processes continue during modern climate change, future loss of summer Arctic sea ice will accelerate the thawing of Siberian permafrost.van der Meulen, B., Gingerich, P.D., Lourens, L.J., Meijer, N., van Broekhuizen, S., van Ginneken, S., Abels, H.A., 2020. Carbon isotope and mammal recovery from extreme greenhouse warming at the Paleocene–Eocene boundary in astronomically-calibrated fluvial strata, Bighorn Basin, Wyoming, USA. Earth and Planetary Science Letters 534, 116044. addition of isotopically-depleted carbon to the ocean and atmosphere caused a carbon isotope excursion (CIE) and global greenhouse warming during the Paleocene–Eocene Thermal Maximum (PETM) circa 56 million years ago. The body of the CIE is followed by a recovery interval that is key to understanding Earth's capacity for carbon uptake, mechanisms of carbon uptake, and biotic responses following an extreme greenhouse warming event. Expanded terrestrial stratigraphic sections in the Bighorn Basin of Wyoming provide exceptionally high-resolution records of the CIE and can be linked directly to the mammalian fossil record.Here, we provide carbon isotope records of unprecedented resolution measured on in-situ pedogenic carbonate nodules in two parallel 8-km-spaced sections of upper Paleocene and lower Eocene fluvial sediments in the northern Bighorn Basin. We find consistent precession-driven sedimentary cycles in the two sections. Cycle thicknesses show significant lateral, and thus vertical, variation, demonstrating that astronomical age models constructed for fluvial successions require detailed sedimentary facies analysis of parallel sites.Plotting the high-resolution carbon isotope records in time using our astronomical age model for the correlated sections indicates a CIE body duration of 101 ± 9 kyr. The CIE shows an initial recovery step of +2.7 ± 1.0‰. This step occurs across the single, well-developed paleosol marker bed known as Purple-4, which represents a time interval of up to 15 kyr. The rapidity of recovery at the end of the CIE body is remarkable in light of existing hypotheses for carbon removal from the ocean–atmosphere system. Concurrent mammal finds show that the transition from faunal zone Wa-0 to faunal zone Wa-1 occurred in two steps, with a transitional Wa-R fauna preceding the CIE initial recovery step and Wa-1 fauna following the step.van der Reest, A.J., Currie, P.J., 2020. Preservation frequency of tissue-like structures in vertebrate remains from the upper Campanian of Alberta: Dinosaur Park Formation. Cretaceous Research 109, 104370. recent years, several papers have claimed that soft tissue can preserve within bone matrix of extinct vertebrates, some dating back over 100 million years. Work conducted on specimens from Montana suggested sediment type may influence preservation of original tissues and proteins. An alternative hypothesis is that soft tissue preservation may be linked to the time that a specimen is exposed to the environment prior to burial. The time of exposure can be estimated by the degree of disarticulation of a skeleton. A study was conducted to determine if these factors truly contribute to the preservation of soft tissue-like structures in the geological record. This study is not intended to verify the presence of proteins but is simply to determine how common are macrostructures that look like soft tissue preservation. Samples were placed into a 0.5?M solution of (ethylenedinitrilo)tetraacetic acid, disodium salt, dihydrate (EDTA) for two months to dissolve mineral components. All specimens studied were collected from the Dinosaur Park Formation (upper Campanian) to minimize stratigraphic variation that may influence preservation. Dissolution of vertebrate remains sampled indicate an unexpectedly high rate of structural preservation. Fifteen dinosaur, two crocodilian, one fish, and one turtle were sampled for a total of nineteen specimens. Specimens were chosen based on sediment type and degree of articulation. Approximately half of the samples were recovered from sandstones, and the other half originated in mudstones. Additionally, approximately half of the samples were collected from articulated or closely associated skeletons, and the other half were taken from isolated bones or specimens from micro vertebrate sites. Of the nineteen specimens tested, eighteen specimens produced “vessel” structures, eighteen had extracellular organic-like matter, and seven revealed “osteocyte” structures. Although “vessel” and extracellular organic-like structures are not associated to a specific matrix type or degree of association, “osteocyte” structures appear to be associated more often with articulated/associated specimens, especially if they are preserved in sandstones.van Mourik, L.M., Lava, R., O'Brien, J., Leonards, P.E.G., de Boer, J., Ricci, M., 2020. The underlying challenges that arise when analysing short-chain chlorinated paraffins in environmental matrices. Journal of Chromatography A 1610, 460550. short-chain chlorinated paraffins (SCCPs) are listed on several monitoring programs, validated methods are essential. However, their complexity and the lack of commercially available certified reference materials (RMs) hinder a proper validation of methods. Instead, one method is usually ‘validated’ by evaluating performances and results of spiked materials with that of one other method, which could easily lead to unreliable results.This study evaluated four analytical methods with different principles (i.e. comprehensive two dimensional GC coupled to a micro electron capture detector, developed for this study, chloride enhanced atmospheric pressure chemical ionization triple quadrupole time of flight MS (APCI-QToF-HRMS), GC coupled to an electron capture negative ion low resolution MS (GC–ECNI–LRMS) and carbon skeleton GC–MS), investigated the comparability in SCCP determination in spiked and naturally contaminated samples and determined SCCP amounts in candidate RMs for possible certification.The results cast doubt on the use of the most commonly applied method (i.e. GC–ECNI–LRMS), as well as using spiked materials for method validation. The APCI-QToF-HRMS method was found most promising as it achieves the required MS resolution (>21,000), is relatively fast and can detect also other CPs. The suitable identified SCCP levels in the candidate RMs and the agreement in results between the methods bring the first certification of a RM for SCCPs within reach.Vance, S.D., Melwani Daswani, M., 2020. Serpentinite and the search for life beyond Earth. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20180421. from serpentinization is a source of chemical energy for some life forms on Earth. It is a potential fuel for life in the subsurface of Mars and in the icy ocean worlds in the outer solar system. Serpentinization is also implicated in life’s origin. Planetary exploration offers a way to investigate such theories by characterizing and ultimately searching for life in geochemical settings that no longer exist on Earth. At present, much of the current context of serpentinization on other worlds relies on inference from modelling and studies on Earth. While there is evidence from orbital spectral imaging and martian meteorites that serpentinization has occurred on Mars, the extent and duration of that activity has not been constrained. Similarly, ongoing serpentinization might explain hydrogen found in the ocean of Saturn’s tiny moon Enceladus, but this raises questions about how long such activity has persisted. Titan’s hydrocarbon-rich atmosphere may derive from ancient or present-day serpentinization at the bottom of its ocean. In Europa, volcanism or serpentinization may provide hydrogen as a redox couple to oxygen generated at the moon’s surface. We assess the potential extent of serpentinization in the solar system’s wet and rocky worlds, assuming that microfracturing from thermal expansion anisotropy sets an upper limit on the percolation depth of surface water into the rocky interiors. In this bulk geophysical model, planetary cooling from radiogenic decay implies the infiltration of water to greater depths through time, continuing to the present. The serpentinization of this newly exposed rock is assessed as a significant source of global hydrogen. Comparing the computed hydrogen and surface-generated oxygen delivered to Europa’s ocean reveals redox fluxes similar to Earth’s. Planned robotic exploration missions to other worlds can aid in understanding the planetary context of serpentinization, testing the predictions herein.Vane, C.H., Kim, A.W., Moss-Hayes, V., Turner, G., Mills, K., Chenery, S.R., Barlow, T.S., Kemp, A.C., Engelhart, S.E., Hill, T.D., Horton, B.P., Brain, M., 2020. Organic pollutants, heavy metals and toxicity in oil spill impacted salt marsh sediment cores, Staten Island, New York City, USA. Marine Pollution Bulletin 151, 110721. cores from Staten Island's salt marsh contain multiple historical oil spill events that impact ecological health. Microtox solid phase bioassay indicated moderate to high toxicity. Multiple spikes of TPH (6524 to 9586 mg/kg) and Σ16 PAH (15.5 to 18.9 mg/kg) were co-incident with known oil spills. A high TPH background of 400–700 mg/kg was attributed to diffuse sources. Depth-profiled metals Cu (1243 mg/kg), Zn (1814 mg/kg), Pb (1140 mg/kg), Ni (109 mg/kg), Hg (7 mg/kg), Cd 15 (mg/kg) exceeded sediment quality guidelines confirming adverse biological effects. Changes in Pb206/207 suggested three metal contaminant sources and diatom assemblages responded to two contamination events. Organic and metal contamination in Saw Mill Creek Marsh may harm sensitive biota, we recommend caution in the management of the 20–50 cm sediment interval because disturbance could lead to remobilisation of pre-existing legacy contamination into the waterway.Vasilyeva, G., Kondrashina, V., Strijakova, E., Ortega-Calvo, J.-J., 2020. Adsorptive bioremediation of soil highly contaminated with crude oil. Science of The Total Environment 706, 135739. to the extended oil extraction and transportation in Russia and other oil-producing countries, many lands remain contaminated because of accidental spills. This situation requires the cost-effective and efficient remediation of petroleum-contaminated soils. Bioremediation of soils contaminated with high concentrations of crude oil is usually hampered by high toxicity thresholds for microbial degraders. We have performed a two-year microfield experiment on the influence of a mixed adsorbent (ACD) composed of granular activated carbon and diatomite on bioremediation of a grey forest soil contaminated with crude oil at concentrations (5–15 % w/w) that would theoretically not result in a successful pollutant removal due to toxicity. Remediation of these soils was evaluated after treating with the ACD adsorbent (from 4 to 12% w/w) and a biopreparation (BP) containing hydrocarbon-degrading bacteria, separately or in combination. Reduction of total petroleum hydrocarbons content was significantly greater in highly contaminated soils with the combined amendments than in the respective controls (through the activation of indigenous degrading microorganisms by fertilizing and mixing) by 9-10% and 5-8% at the end of the first and second years, respectively, depending on the contamination level. Significantly higher counts of petroleum-degrading microorganisms (as indigenous and introduced by the BP), as well as much less phytotoxicity was detected in the ACD-amended soils, as compared with the samples without adsorbent. In addition, the ACD mixture drastically reduced the wash-out of polar petroleum metabolites (evidently oxidized hydrocarbons) and the phytotoxicity of the lysimetric waters, especially in highly contaminated soils. The results indicate that the mixture of activated carbon and diatomite is a prospective adsorbent for the in situ bioremediation of soils highly contaminated with crude oil.Vaz, E., Penfound, E., 2020. Mars terraforming: A geographic information systems framework. Life Sciences in Space Research 24, 50-63. study has developed a GIS framework that uses spatial environmental and climate data to better understand areas on Earth that share the most environmental similarities to Mars. The purpose of developing this framework is to determine which vegetation is most likely to survive in closed bioregenerative life support systems on Mars, using as many in-situ materials and environmental elements as possible. Using remotely sensed climate data, digital elevation models, and vegetation occurrence data sourced from the Global Biodiversity Information Facility, 2018, Global Biodiversity Information Facility, 2018, Global Biodiversity Information Facility, 2018, three Mars-like study areas on Earth were analysed (the Antarctic Peninsula, Ellesmere Island, and Devon Island). This study found that plants that are part of the Bryophyte and Tracheophyta phyla are worthy of further research in regard to possible vegetation candidates that could be brought to Mars. In addition, the most promising candidate of the entire study is the genus Poa, which is found in the phylum Tracheophyta.Vila, J., Tian, Z., Wang, H., Bodnar, W., Aitken, M.D., 2020. Isomer-selective biodegradation of high-molecular-weight azaarenes in PAH-contaminated environmental samples. Science of The Total Environment 707, 135503. aromatic nitrogen heterocycles, or azaarenes, normally co-occur with polycyclic aromatic hydrocarbons (PAHs) in contaminated soils. We recently reported that nontarget analysis using high resolution mass spectrometry of samples from four PAH-contaminated sites revealed a previously unrecognized diversity and abundance of azaarene isomers and their methylated derivatives. Here we evaluated their biodegradability by natural microbial communities from each site in aerobic microcosm incubations under biostimulated conditions. The removal of total quantifiable azaarenes ranged from 15 to 85%, and was related to the initial degree of weathering for each sample. While three-ring azaarenes were readily biodegradable, the five-ring congeners were the most recalcitrant. Microbial-mediated removal of four-ring congeners varied for different isomers, which might be attributed to the position of the nitrogen atom that also influences the physicochemical properties of azaarenes and possibly the susceptibility to transformation by relevant microbial enzymes. The presence of methyl groups also influenced azaarene biodegradability, which decreased with increasing degree of methylation. Several oxidation products of azaarenes were detected, including ketones and dioxygenated derivatives of three- and four-ring compounds. Our results indicate the susceptibility of some azaarenes to bioremediation, while suggesting the potential implications for risk from the persistence of less-biodegradable isomers and the formation of oxidized-azaarene derivatives.Vo, N.N.Q., Nomura, Y., Muranaka, T., Fukushima, E.O., 2019. Structure–activity relationships of pentacyclic triterpenoids as inhibitors of cyclooxygenase and lipoxygenase enzymes. Journal of Natural Products 82, 3311-3320. triterpenes may be active agents and provide a rich natural resource of promising compounds for drug development. The inhibitory activities of 29 natural oleanane and ursane pentacyclic triterpenes were evaluated against four major enzymes involved in the inflammatory process: 5-LOX, 15-LOX-2, COX-1, and COX-2. It was found that 3-O-acetyl-β-boswellic acid potently inhibited human 15-LOX-2 (IC50 = 12.2 ± 0.47 μM). Analysis of the structure–activity relationships revealed that the presence of a hydroxy group at position 24 was beneficial in terms of both 5-LOX and COX-1 inhibition. Notably, the introduction of a carboxylic acid group at position 30 was important for dual 5-LOX/COX inhibitory activity; furthermore, its combination with a carbonyl group at C-11 considerably increased 5-LOX inhibition. Also, the presence of an α-hydroxy group at C-2 or a carboxylic acid group at C-23 markedly suppressed the 5-LOX activity. The present findings reveal that the types and configurations of polar moieties at positions C-2, -3, -11, -24, and -30 are important structural aspects of pentacyclic triterpenes for their potential as anti-inflammatory lead compounds.Volkov, D.S., Rogova, O.B., Proskurnin, M.A., 2020. Photoacoustic and photothermal methods in spectroscopy and characterization of soils and soil organic matter. Photoacoustics 17, 100151. sums up the application of photoacoustic and photothermal spectroscopies for the analysis and characterization of soils and soil organic matter and discusses the outlooks in this area.von Hegner, I., 2020. Extremophiles: a special or general case in the search for extra-terrestrial life? Extremophiles 24, 167-175. time immemorial life has been viewed as fragile, yet over the past few decades it has been found that many extreme environments are inhabited by organisms known as extremophiles. Knowledge of their emergence, adaptability, and limitations seems to provide a guideline for the search of extra-terrestrial life, since some extremophiles presumably can survive in extreme environments such as Mars, Europa, and Enceladus. Due to physico-chemical constraints, the first life necessarily came into existence at the lower limit of its conceivable complexity. Thus, the first life could not have been an extremophile; furthermore, since biological evolution occurs over time, then the dual knowledge regarding what specific extremophiles are capable of, and to the analogue environment on extreme worlds, will not be sufficient as a search criterion. This is because, even though an extremophile can live in an extreme environment here-and-now, its ancestor however could not live in that very same environment in the past, which means that no contemporary extremophiles exist in that environment. Furthermore, a theoretical framework should be able to predict whether extremophiles can be considered a special or general case in the galaxy. Thus, a question is raised: does Earth’s continuous habitability represent an extreme or average value for planets? Thus, dependent on whether it is difficult or easy for worlds to maintain the habitability, the search for extra-terrestrial life with a focus on extremophiles will either represent a search for dying worlds, or a search for special life on living worlds, focusing too narrowly on extreme values.Voosen, P., 2020. Planetary turmoil unleashed during Solar System infancy. Science 367, 350-351. early maelstrom shaped our Solar System. Sometime after the planets took shape from primordial gas and dust, resonant tugs between the giant planets threw their orbits out of kilter. The gravity of the errant giants blasted Pluto and its many icy neighbors into the far-out Kuiper belt. The instability also scattered oddball moons and asteroids and triggered smaller bodies to pummel the inner planets.Now, that scenario is experiencing some upheaval of its own.Scars on the Moon had convinced many planetary scientists that the storm hit about 3.95 billion years ago, 650 million years after the Solar System formed. But this model has long had a flaw: Mercury, Venus, Earth, and Mars would likely not have survived such a late assault. And over the past few years, a new timeline has begun to emerge, one that shifts the chaos earlier, to less than 100 million years after the system's creation—and perhaps as few as 10 million years. “The tides are moving and people are now more and more convinced that the instability happened early,” says David Nesvorn?, a planetary scientist at the Southwest Research Institute (SwRI) in Boulder, Colorado. Several new papers explore what triggered this early instability and how it can explain a host of Solar System quirks.Two decades ago, scientists recognized that planets must have migrated to create the modern Solar System. A group including Alessandro Morbidelli, a planetary scientist at the University of C?te d'Azur, gathered in Nice, France, for 1 year to hash out the idea, creating what's known as the Nice model (Science, 17 July 2009, p. 262). As the model now goes, after the giant planets formed out of the gas disk, Jupiter drew its fellow giants into a resonant chain of orbits where, for example, Saturn orbited the Sun three times for two turns of Jupiter. The surrounding gas acted as a damping agent, calming any instability like an air conditioner in a room of irritable siblings. But once the gas dissipated, the collective push and pull of giant planets' masses, agitated by nearby planetary building blocks, unleashed chaos.The turmoil came relatively late, suggested lunar rocks collected from impact craters by the Apollo astronauts. The ages of the rocks seemed to indicate that the Moon suffered a cataclysmic assault, dubbed the Late Heavy Bombardment (LHB), 3.95 billion years ago, sandwiched by hundreds of millions of years of quiet. But over the past few years this story has evaporated, says Nicolle Zellner, a lunar geochemist at Albion College. New work suggests rocks collected by astronauts at multiple craters, once believed to represent simultaneous strikes, are instead debris from a single impact, 3.95 billion years ago, that created Imbrium Basin. More precise dating of Apollo samples and meteorites ejected from the Moon shows that the impacts responsible took place as many as 4.3 billion years ago—or well after the supposed LHB. “The idea of a very strong cataclysm has gone away,” Zellner says.Planetary dynamicists have welcomed the LHB's vanishing act. Their models had highlighted a puzzle: A late catastrophe would have either destroyed the rocky planets of the inner Solar System or disrupted their stately, nearly circular orbits, flat with the Solar System's plane. “This was my first red flashing light,” says Kevin Walsh, a planetary scientist at SwRI.Now, in a paper accepted for publication in Icarus, Morbidelli and co-authors show that such a late instability wouldn't work in any case. Their computer modeling indicates that, for a late instability to have created the current Solar System, a large gap would have had to exist between Neptune and the encircling disk of planetary building blocks outside its orbit. But the gap rarely appears in the models. And without the gap, it's impossible to delay the catastrophe, Morbidelli says.Freed from the late constraint, planetary scientists are now exploring how an earlier cataclysm could explain odd features of the Solar System. Over the past few years, Matthew Clement of the Carnegie Institution for Science, Walsh, and others have shown in computer simulations that an instability less than 10 million years after Solar System formation would allow the inner planets to coalesce in peace. An early instability would also scour away planet-forming material near Mars and the asteroid belt, explaining their weirdly low masses. And in a paper published last month in the Monthly Notices of the Royal Astronomical Society: Letters, they show that as Saturn moved away from Jupiter near the end of the instability, a final tug between them might have flung away asteroids in orbits far removed from the orbital plane, giving the asteroid belt its current compact structure. “We kind of simplify the whole story,” Clement says. “We can have one event explain all these problems.”Still, “The details are strongly debated,” says Thomas Kruijer, a geochemist at Lawrence Livermore National Laboratory. There's little direct evidence for such an early instability, and at least two other scenarios that could explain how the rocky planets survived. Clement also has yet to reconcile a similarity between noble gases measured by the Rosetta spacecraft around the comet 67P and features of Earth's atmosphere, which suggests the instability likely caused Earth to be bombarded with a hail of comets after it was solid—not before.But Kruijer says a bombardment within the first 100 million years of the Solar System is plausible. Perhaps the best evidence for it is now found near Jupiter, Nesvorn? adds. There, following Jupiter in its orbit, spins a binary asteroid named Patroclus-Menoetius. The icy composition of its two bodies indicates they formed in the far reaches of the Solar System and were implanted into Jupiter's wake during the instability. In a 2018 paper, Nesvorn? and co-authors showed there's no way the binary would have survived 600 million years in the outer Solar System—collisions would have ground it up after only 100 million years. “That's a very solid constraint” supporting an early instability, Morbidelli says.The hunt is on for more observations that can parse what happened during those first 100 million years, whether from asteroid samples, clusters of primordial asteroid families, or craters on the Moon and Mars. “Now, the question is, was it a few million years after or 80 million years?” Morbidelli says. “Honestly we don't know.”Voskos, I., Vika, E., 2020. Prehistoric human remains reviewed: Palaeopathology and palaeodiet in Neolithic and Chalcolithic Cyprus, Limassol district. Journal of Archaeological Science: Reports 29, 102128. current paper presents the results from the recent reexamination of osteological material deriving from Ceramic Neolithic and Chalcolithic sites of the Limassol district, Cyprus. The available skeletal material was macroscopically examined in order to identify possible palaeopathological lesions, while stable isotope analyses (carbon and nitrogen) were conducted aiming to reconstruct past diets. Although only a small percentage of the samples provided acceptable collagen, this study still offers valuable insights into the economic strategies and everyday practices during the mid-5th to late-4th millennium B.C. It is also noted, that nearly all the available skeletal material from the Ceramic Neolithic period on the island was sampled. This study, therefore, provides a useful basis for future comparative research.Wadley, L., Backwell, L., d’Errico, F., Sievers, C., 2020. Cooked starchy rhizomes in Africa 170 thousand years ago. Science 367, 87-91.: Plant carbohydrates were undoubtedly consumed in antiquity, yet starchy geophytes were seldom preserved archaeologically. We report evidence for geophyte exploitation by early humans from at least 170,000 years ago. Charred rhizomes from Border Cave, South Africa, were identified to the genus Hypoxis L. by comparing the morphology and anatomy of ancient and modern rhizomes. Hypoxis angustifolia Lam., the likely taxon, proliferates in relatively well-watered areas of sub-Saharan Africa and in Yemen, Arabia. In those areas and possibly farther north during moist periods, Hypoxis rhizomes would have provided reliable and familiar carbohydrate sources for mobile groups.Editor's summary: Middle Stone Age cooking. Early evidence of cooked starchy plant food is sparse, yet the consumption of starchy roots is likely to have been a key innovation in the human diet. Wadley et al. report the identification of whole, charred rhizomes of plants of the genus Hypoxis from Border Cave, South Africa, dated up to 170,000 years ago. These archaeobotanical remains represent the earliest direct evidence for the cooking of underground storage organs. The edible Hypoxis rhizomes appear to have been cooked and consumed in the cave by the Middle Stone Age humans at the site. Hypoxis has a wide geographical distribution, suggesting that the rhizomes could have been a ready and reliable carbohydrate source for Homo sapiens in Africa, perhaps facilitating the mobility of human populations.Wagner, P., 2020. High-resolution dating of Paleozoic fossils. Science 367, 249. about the quality of the fossil record frequently focus on completeness—that is, the proportion of species that existed for which scientists have fossil samples. An equally important aspect of quality is how finely the ages of fossils and durations of major evolutionary events can be resolved. Paleontologists and other biologists typically date fossils using the general ages of the chronostratigraphic units assigned to the rock strata yielding the fossils. For example, if a fossiliferous bed comes from the Rhuddanian Gasworks Sandstone, then the ages assigned to the fossils are usually 443.8 to 440.8 million years. On page 272 of this issue, Fan et al. (1) report on their use of constrained optimization (CONOP) (2) in biochronological analyses of fossil-bearing layers containing 11,000+ marine invertebrate species from 3000+ sections of sedimentary rocks, which constrain ages to a fraction of that range.Their data, taken from the Geobiodiversity Database (GBDB) (3), span the Paleozoic through the Early Triassic. Although GBDB data are limited (largely) to China, the different continental plates that compose modern China fortuitously span multiple biogeographic realms throughout most of the Paleozoic. CONOP aligns fossil-bearing beds from different rock sections (e.g., spans of rocks from quarries, road cuts, and natural erosion on hills and mountains) by maximizing sets of species with first and last appearances in the same order in as many sections as possible. By integrating these analyses with radiometric dates and other geological data (4), the authors resolved the age of an average bed (and thus the average first and last appearance times of species) to within 26,000 years. This new level of dating specificity is similar to moving from a system in which all people who lived in the same century are considered to be contemporaries to one in which only people who lived during the same 6-month period are deemed to be contemporaries.Armed with exact first and last appearance dates for thousands of species, the authors then developed what are, as they themselves stress, a set of fairly preliminary analyses of Paleozoic diversity. The authors deliberately eschew sophisticated analyses of origination and extinction dynamics or sampling dynamics used in other works with much coarser temporal resolution than that yielded by CONOP (5, 6). This approach permits contrasting the basic patterns with those that would be implied had the authors chosen to “bin” these data into predefined chronostratigraphic analyses, as nearly all prior diversity studies have done.In doing so, some noteworthy patterns emerge. For example, despite failing to correct for the Signor-Lipps effect (imperfect sampling that causes sudden extinctions to look gradual or rapid radiations to look protracted) (7), CONOP results indicate rapid declines in richness of marine invertebrate species prior to the end-Ordovician and end-Permian extinctions. Similarly, Fan et al. found the rebound after the end-Ordovician extinction to be much more rapid than prior studies suggest. Furthermore, CONOP reconstructions show patterns over hundreds of thousands of years that prior studies, which lumped together occurrences over millions of years, cannot hope to reveal.Analysis of the Great Ordovician Biodiversification Event (GOBE) (8) offered a different type of unexpected result. Fan et al.'s study suggests that the GOBE began 20+ million years earlier than expected, during the late Cambrian. Given that late Cambrian sampling for many marine invertebrates is relatively poor compared to their fossil records earlier in the Cambrian and in the Ordovician (9), one would predict emergence of an opposite pattern: Any late Cambrian diversification should not have appeared until the Ordovician.The CONOP analyses of GBDB data have implications for how organismal biologists and molecular phylogeneticists perform analyses of species, including fossils, in the future. Recent years have seen a proliferation of methods such as tip-data (10) and fossilized birth-death models (11), which include fossilized anatomical data and modern anatomical and molecular data. Accounting for uncertainty in the true ages of first and last appearances can strongly affect the results of such analyses (12). Current approaches for dealing with this uncertainty often assume that uncertainty is large; for example, if a species's first appearance is in the Rhuddanian age, then all dates within the Rhuddanian are equally probable first appearances (13). However, as the new study makes clear, biochronological analyses will make some dates within the Rhuddanian much more probable than others.Of course, many extant organisms do not fossilize as well as shell-bearing marine invertebrates, and their oldest fossil representatives often are known from exceptional preservation in the lagerst?tte sedimentary deposits (14). CONOP and related biochronology methods (15) require species from multiple beds in multiple sections to infer ages for fossil occurrences. However, fossiliferous beds preserving typical assemblages of shell-containing invertebrates usually occur above and below the lagerst?tte. Constraining the ages of those beds will simultaneously constrain the ages of the lagerst?tte. With respect to important evolutionary questions, the development of new datasets and methods of the sort used by Fan et al. will further evolutionary biology as a whole, not just paleontology.References and Notes1. J.-x. Fan et al., Science 367, 272 (2020).2 P. M. Sadler, R. A. Cooper, in High-Resolution Stratigraphic Approaches in Paleontology, P. Harries, Ed. (Plenum, 2003), vol. 21, pp. 49–943. GBDB, .4. P. M. Sadler, Bull. Geosci. 87, 681 (2012).5. M. Foote et al., Proc. Biol. Sci. 285, 20180122 (2018).6. M. Foote et al., J. Geol. Soc. London 176, 1038 (2019).7. P. W. Signor, J. H. Lipps, Spec. Pap. Geol. Soc. Am. 190, 291 (1982).8. T. Servais et al., Palaeogeogr. Palaeoclimatol. Palaeoecol. 294, 99 (2010).9. Y.-D. Zhang et al., Palaeoworld 28, 1 (2019).10. F. Ronquist et al., Syst. Biol. 61, 973 (2012).11. T. A. Heath, J. P. Huelsenbeck, T. Stadler, Proc. Natl. Acad. Sci. U.S.A. 111, E2957 (2014).12. J. Barido-Sottani et al., Proc. Biol. Sci. 286, 20190685 (2019)13. D. Silvestro et al., Paleobiology 45, 546 (2019).14. D. T. Ksepka et al., Syst. Biol. 64, 853 (2015).15. J. Alroy, Paleobiology 20, 191 (1994).Waldrop, M.M., 2020. News Feature: Small-scale fusion tackles energy, space applications. Proceedings of the National Academy of Sciences 117, 1824. are underway to exploit a strategy that could generate fusion with relative ease.On July 14, 2015, nine years and five billion kilometers after liftoff, NASA’s New Horizons spacecraft passed the dwarf planet Pluto and its outsized moon Charon at almost 14 kilometers per second—roughly 20 times faster than a rifle bullet.The images and data that New Horizons painstakingly radioed back to Earth in the weeks that followed revealed a pair of worlds that were far more varied and geologically active than anyone had thought possible. The revelations were breathtaking—and yet tinged with melancholy, because New Horizons was almost certain to be both the first and the last spacecraft to visit this fascinating world in our lifetimes.Unless, that is, Samuel Cohen succeeds with the offbeat fusion reactor that he’s developing at the Princeton Plasma Physics Laboratory in New Jersey.Cohen’s current prototype is a clear plastic cylinder that sits in the middle of his lab amidst a dense mass of cables, magnets, and power supplies, emitting a violet pulse of light every two seconds like a two-meter-long strobe light. “We’re only using hydrogen right now,” Cohen explains, referring to the ionized plasma inside the tube that’s emitting the flashes. So there are no actual fusion reactions taking place; that’s not in his research plan until the mid-2020s, when he hopes to be working with a more advanced prototype at least three times larger than this one.If that hope pans out and his future machine does indeed produce more greenhouse gas–free fusion energy than it consumes, Cohen and his team will have beaten the standard timetable for fusion by about a decade—using a reactor that’s just a tiny fraction of the size and cost of the huge, donut-shaped “tokamak” devices that have long devoured most of the research funding in this field. The flagship of this tokamak approach, the International Thermonuclear Experimental Reactor (ITER) now under construction in France, will be twice as large as any fusion reactor before it, will cost at least $20 billion to build, and isn’t expected to start producing fusion energy until the mid-2030s.If and when Cohen does reach his fusion energy milestone, he will likely have company. His device is just one of a family of small, alternative reactor projects designed to exploit a phenomenon known as the field-reversed configuration (FRC): a dense mass of ionized plasma that holds itself together something like a smoke ring and that could allow researchers to achieve fusion conditions with comparatively little effort. Among the members of this family are some of the best-known fusion upstarts: firms such as TAE Technologies (formerly TriAlpha Energy) in Foothill Ranch, California, and Helion Energy in Redmond, Washington.“There's been a rejuvenation in that whole area” of FRCs, says Stephen Dean, a nuclear engineer who has championed fusion energy for more than 50 years. “All of the projects have good ideas, all of them are doing good work.” But even if some or all of them do end up producing fusion energy in the lab at some point in the 2020s, he says, all of them are eventually going to have to build a real, power-producing test reactor—something that’s not likely to happen for a decade or more.Pluto PowerThat’s why Cohen takes the long view. His goal is an ultra-compact reactor that will use a fuel mix containing helium-3, an isotope that yields a particularly clean form of fusion with minimal radiation risk. But the stuff is exceedingly rare, he says: “So we’re not trying to make power for everybody.” Instead, the goal is niche uses such as spacecraft propulsion, in which the reactor would fire a very tenuous plasma from one end so that it functions as a rocket (1).Such a direct fusion drive (DFD) would produce only the most infinitesimal hint of acceleration, says Cohen—about like pushing an 18-wheel truck with your fingertip. But in space, that push would have nothing to resist it. After a year or two, such a rocket could get a 10-ton spacecraft halfway to Pluto, traveling well over 50 kilometers per second.“Then you’d turn around and decelerate,” says Cohen. “And when you got to Pluto, you’d go into orbit.” At that point, the reactor would turn off the ion rocket and convert itself into a one-megawatt electrical power source. “Some of that power you can use to send high-definition video back,” says Cohen. “And some of it you can beam down to a lander that you've placed on the surface, so it could drive around and drill holes in the ice.”The same type of DFD rockets could also be used to explore the moons of Jupiter and Saturn, says Cohen, or the icy bodies of the Kuiper Belt beyond Pluto, or anywhere else in the outer solar system.Plasma ProblemOf course, there’s a reality check, says Dean: “If you want to make a fusion exhaust system, you still have to be able to make the fusion plasma.” It’s a trick that neither Cohen nor anyone else has yet managed. Researchers have been trying to harness fusion power since the 1920s and 1930s, when they first realized that stars like the sun get their energy from thermonuclear reactions at their core. And yet, as the many delays and cost overruns on ITER have made clear, success is still years away at best.Still, old hands like Cohen know the pitfalls of fusion research as well as anyone. Until the late 1990s, his professional life revolved around ITER, which is supposed to be the ultimate expression of the oldest and most promising approach to fusion energy: magnetic confinement. In theory, this is just a matter of ionizing an appropriate mix of light isotopes, trapping them in a magnetic field, and heating them to millions of degrees while simultaneously squeezing them to densities approximating the sun’s core. The isotopes will then start fusing into larger nuclei while releasing vast amounts of energy.In practice, though, hot, ionized plasma doesn’t like being confined by a magnetic field; it twists and tries to escape like a living thing. Thus the appeal of the tokamak design, which was a major breakthrough when Soviet physicists introduced it in the 1960s. Thanks to strong magnetic fields that guide the ionized isotopes around and around its donut-shaped vacuum chamber, a tokamak could keep the plasma under control better than almost anything else at the time. And thus the funding agencies’ willingness to keep sinking billions of dollars into ITER: a gargantuan tokamak whose 23,000-ton weight will be three times that of the Eiffel Tower, and whose 29 by 29-meter vacuum chamber will be as tall as a seven-story building. This is the scale that a tokamak will need to achieve the elusive goal of “break-even,” in which the plasma produces more fusion energy than the machine requires to operate.Except that to Cohen and an increasing number of other fusion researchers, ITER has laid bare the tokamak’s many drawbacks as a practical power source. These start with the facility's size, cost, and complexity, which are so far beyond what power companies are willing to accept that they have all but given up on fusion, says Dean: “I can’t even talk to anyone in the utilities who knows what a tokamak is anymore.”And then there’s the neutron problem. The physics of tokamaks limits them to burning a mix of the hydrogen isotopes deuterium and tritium. This fuel is by far the easiest to ignite, requiring comparatively low plasma temperatures of about a hundred million degrees Kelvin. But when the two nuclei fuse to form a helium-4 nucleus (two protons plus two neutrons), they eject the leftover neutron at high energy. And because that particle is electrically neutral and can’t be controlled with magnetic fields, it ends up smashing into the tokamak’s inner walls and wreaking havoc with their structural integrity. So the walls will have to be replaced perhaps once per year—a maintenance burden that no power company wants to shoulder.A Different ConfigurationBy the late 1990s such hurdles were spurring Cohen and others to take a fresh look at FRCs, which had been discovered in the 1960s.The key advantage was that an FRC doesn’t keep its plasma in line by brute force, the way a tokamak does. Instead, the FRC plasma is self-organizing. That is, the magnetic fields that hold it together are mostly generated by currents flowing through the plasma itself, rather than in external coils. This self-organizing property can be found in other plasma structures, which have names such as “spheromak” and “dense plasma focus,” says Cohen. But all else being equal, FRC plasmas are much hotter and denser than the others.Once it’s set up, an FRC actually looks less like a smoke ring than an elongated American football, or maybe a short cigar. The “field-reversed” name comes from the way magnetic fields curve around the football’s outside and then loop backward through its long axis. This structure tends to dissipate in less than a millisecond, unfortunately—one big reason why only a handful of researchers stuck with the FRCs after tokamaks came along. But the appeal remained: Find a way to stabilize the FRC, and the reactor wouldn’t have to be much more than a cylindrical vacuum chamber with a comparatively mild magnetic field running down the midline to hold the plasma football in place.Self-organization also should make it comparatively easy for the dense, hot plasma inside the FRC to reach the threshold required for fusion. And not just deuterium-tritium fusion, either: FRCs could potentially reach the much higher temperatures required to burn aneutronic fuels such as deuterium-helium–3 or proton-boron–11. These reactions emit most of their fusion energy in the form of charged particles such as protons or helium-4 nuclei, which—unlike neutrons—can be captured and controlled with magnetic fields. This would make it much easier to extract energy from the fusion products before they can damage the reactor walls, and would allow the reactor to get by with minimal shielding.So in principle, says Cohen, FRC-based reactors could solve the tokamak’s size, complexity, and neutron problems at a stroke. But to make that work in practice, he says, researchers have had to make a series of critical design choices: how to form, stabilize, and control the FRC, how to heat it, what kind of fusion fuel to use, and so on. “You multiply all those options,” he says, “you get roughly 80 different potential FRCs.”TAE has been working on one such option since 1998, when it was founded with the goal of fusing protons with boron-11 nuclei. This pB11 reaction is in some ways the ultimate in neutron-free fusion: Its output is just a triplet of positively charged helium-4 nuclei, which are commonly known as alpha particles (thus the company’s original name, TriAlpha.) But the reaction also has some significant downsides. For example, its multibillion-degree threshold for fusion is about 20 or 30 times higher than the temperatures required for the deuterium-tritium reaction that ITER will use. Also, it has about half as much energy yield per fusion event.So to make pB11 work, TriAlpha’s design has to be correspondingly ambitious (2). The idea is to cap the reactor on each end with two electromagnetic cannons pointed barrel to barrel. To start things off, each cannon fires a ring of plasma into a central chamber, where the rings merge into a single, furiously spinning FRC. From there, a beam of neutral atoms coming in from the side will simultaneously heat the FRC, supply it with fresh pB11 fuel, and stabilize it by keeping the spin rate up.It took TAE until 2012 to demonstrate this whole process in a prototype machine (albeit with a nonfusing hydrogen plasma), says the company’s CEO, Michl Binderbauer. “We showed these beautiful experiments where, if you start with the standard FRC and you don't do anything, it dies,” he says. “But if you start injecting particles, you slow down the decay and expand how long it lives.” Since then, says Binderbauer, the company has shown that this process can sustain the FRC indefinitely—or at least, for the five or 10 milliseconds it takes the 25-megawatt beam to exhaust the energy that researchers are able to store for each shot.In a working reactor, of course, that beam power would come from the fusion reaction itself, so that the beam and the FRC could keep going as long as the researchers want. That’s a milestone TAE hopes to meet with a pB11-burning prototype well before the end of the 2020s, says Binderbauer. This machine will be roughly the size of four double-decker busses parked end to end, he adds—not small, but still just a fraction of the size of ITER.In Bellevue, Washington, meanwhile, another FRC-based reactor is under development at Helion Energy, which was founded by University of Washington researchers in 2013. Company officials are not discussing their plans publicly at the moment, but they have been relatively open about their approach via their website and publications.Helion’s reactor, like TAE’s, will be a linear tube that uses twin plasma guns to form a stationary FRC in the middle. But instead of trying to sustain the FRC, the Helion device will crush it with an ultrastrong magnetic field until the plasma becomes dense enough and hot enough to fuse. The resulting burst of thermonuclear energy will then cause the ball of plasma to explode outward again, pushing back against the magnetic field and allowing the system to harvest that energy. This cycle will then repeat once per second, generating a steady average power output in much the same way that gasoline explosions do in an internal combustion engine.The Helion reactor will also differ from TAE’s in its choice of fuel. Instead of using pB11, it will burn deuterium and helium-3—an isotope often called a “helion.” This reaction requires a temperature of several hundred million degrees, intermediate between deuterium-tritium and pB11. But it, too, is aneutronic: the final products are two charged particles, an alpha and a proton.Or rather, this fuel is almost aneutronic: It’s impossible to keep the deuterium nuclei in the fuel from reacting with each other and producing at least some neutrons. But those neutrons are low energy and comparatively easy to shield against. And for Helion, the deuterium-deuterium side-reactions are a plus: the products are an almost equal mix of a neutron plus helium-3, and a proton plus tritium—a radioactive isotope that will decay into helium-3 with a half-life of 12.3 years. So in principle, Helion’s reactor can make its own helium-3 fuel, which is otherwise available only in trace amounts extracted from natural gas fields, or produced as a byproduct in Canadian CANDU fission reactors.Space ReactorCohen, for his part, has been pursuing his Princeton Field Reversed Configuration (PFRC) design since 2002, with a strong emphasis on simplicity and compactness (3). The cylindrical plastic vacuum chamber of his current device, PFRC-2, is only 88 centimeters long, with not a plasma cannon or neutral beam injector in sight. Instead, the FRC is generated via a technique first explored by Austrian and Australian physicists and then refined by Cohen himself. He points to four rectangular copper coils that surround the middle of the tube: one each on its front, back, top, and bottom. Each rectangle, in turn, is divided into two smaller rectangles. The idea, says Cohen, is to drive oscillating currents through these coils in a way that sets up a rotating magnetic field inside the tube: a loop of flux that whirls through the plasma like a flipped coin and drags the plasma particles around and around the waist of the cylinder. In the process, he says, “the fields create, stabilize, and heat the FRC”—all in a single deft maneuver.Indeed, that’s what Cohen routinely demonstrates in his lab: Every two seconds, the hydrogen plasma inside is whipped into an FRC, causing a flash. Each flash lasts for only about eight milliseconds, says Cohen, mainly because longer pulses risk melting the cables that supply the antennas with power. “So for the next machine,” he says, “we've got to make better cables”—which should keep the FRCs going indefinitely.In the meantime, Cohen and his group are working on the main goal of PFRC-2, which is to improve the antennas’ ability to heat the plasma. This is crucial, notes Binderbauer: “I know Sam well, we root for each other.” But compared with the temperatures that TAE is already working with, he says, “his plasmas are cold.” Also, he says, it remains to be seen how well the rotating magnetic field approach will work in a full-scale reactor. “I'm not trying to say that it can't be done,” says Binderbauer, “but I think those are some of the things that they're going to have to address.”Still, Cohen remains confident. Sometime in the next few years, if things progress as planned, he and his group will replace this machine with PFRC-3: a device twice as large that will hopefully allow them to achieve FRCs lasting as long as 10 seconds, with plasma temperatures on the order of 60 million K. And a few years after that, the plan calls for moving up to PFRC-4, an even larger machine designed to use live fusion fuel at temperatures of 600 million K.That fuel will be deuterium-helium-3, which Cohen calls “the Goldilocks approach” between deuterium-tritium and pB11. Unlike Helion, however, he plans to keep things simple and forgo any attempt to breed new helium-3. Instead, Cohen will just live with the scarcity of helium-3, and focus on niche applications like spacecraft propulsion—an idea that emerged about a decade ago in discussions with Michael Paluszek, president of a space technology company, Princeton Satellite Systems, New Jersey, which is located just a few miles from Cohen’s lab.Of course, it could be another 10 to 15 years before PFRC-based reactors are working reliably enough for a multi-year deep-space mission, assuming that they work at all. But then, much the same could be said about any of the alternative fusion designs—or for that matter, ITER. Taking the long view is pretty much a requirement for fusion energy research. “If you want to do this really ambitious stuff in the 2030s,” Paluszek says, alluding to DFD missions, “you need to be developing new technology now.”References1. S. Thomas, Fusion-enabled Pluto orbiter and lander (NASA, 2016). . H. Gota et al., Formation of hot, stable, long-lived field-reversed configuration plasmas on the C-2W device. Nucl. Fusion 59, 112009 (2019).3. C. Brunkhorst, B. Berlinger, N. Ferraro, S. A. Cohen, The Princeton FRC Rotating-Magnetic-Field-Experiment RF System in 2007 IEEE 22nd Symposium on Fusion Engineering, (2007), pp. 1–4.Wang, C., He, S., Zou, Y., Liu, J., Zhao, R., Yin, X., Zhang, H., Li, Y., 2020. Quantitative evaluation of in-situ bioremediation of compound pollution of oil and heavy metal in sediments from the Bohai Sea, China. Marine Pollution Bulletin 150, 110787. to the semi-enclosed environment of the Bohai Sea, the ecological effects caused by an oil spill would be significant. A typical in- situ bioremediation engineering project for of oil-spilled marine sediments was performed in the Bohai Sea and a quantitative assessment of the ecological restoration was performed. The bioremediation efficiencies of n-alkane and PAHs in the sediment are 32.84?±?21.66% and 50.42?±?17.49% after 70?days of bioremediation, and 60.99?±?10.14% and 68.01?±?18.60% after 210?days, respectively. After 210?days of bioremediation, the degradation rates of two- to three ring PAHs and four-ring PAHs are 84.44?±?23.03% and 26.62?±?43.76%, respectively. In addition, the concentrations of the heavy metals first increased by 6.00% due to oil spill degradation and release, and then decreased by 72.60% with the degradation of oil caused by bioremediation or vertical migration. According to the continuous tracking monitoring, the composition of the microbial community in the restored area was similar to that in the control area and the clean area in Bohai Sea after 210?days of bioremediation. These results may provide some theoretical and scientific data to understand the degradation mechanism and assessing the ecological remediation efficiency for oil spills in open sea areas.Wang, C., Wu, K., Scott, G.G., Akisanya, A.R., Gan, Q., Zhou, Y., 2020. A new method for pore structure quantification and pore network extraction from SEM images. Energy & Fuels 34, 82-94. structure of porous media is complex yet fundamental to the understanding of transport processes, including single and multiphase fluid flow. Pore network modeling is a valuable tool for studying these processes in many diverse porous media. This paper presents a new method of discretizing the pore space into connected pore elements which capture the pore geometry and topology. This method discards the difference between pore bodies and throats; instead, it treats them equally as pore elements that capture the features of pore structure from the widest to the narrowest part of the pore space (pore body to pore throat), honors the topology, and does not oversegment the pore space. The method is a higher-level discretization of the pore space, compared to other traditional methods, which construct pore throats explicitly. Pore networks were extracted from three test images using the method and the computed flow properties are compared with finite element simulation, in terms of absolute permeability. A reasonable agreement with finite element simulation is achieved, demonstrating the value and functionality of the new pore structure quantification method.Wang, H., Ge, D., Cheng, Z., Zhu, N., Yuan, H., Lou, Z., 2020. Improved understanding of dissolved organic matter transformation in concentrated leachate induced by hydroxyl radicals and reactive chlorine species. Journal of Hazardous Materials 397, 121702. leachate (CL) is commonly featured with high salt and dissolved organic matters (DOM). In this study, molecular transformation of DOM was revealed to identify the reactive mechanisms with (non-) radical reactive species in ozonation, electrolysis and E+-ozonation processes. Chlorine ions were efficiently activated into non-radical reactive chlorine species (RCS) with 245.7?mg/L, which was more dominant in electrolysis. Compared to ozonation, C?OH was increased from 2.6?×?10-4 mg/L into 5.8?×?10-4 mg/L and the generation of Cl?/ClO? could be concluded according to the decline of non-radical RCS in E+-ozonation process. For chromophoric and fluorescent DOM, aromatic compounds and polymerization degree dramatically decreased in E+-ozonation. Lipid-like and CRAM/lignin-like compounds were substantially degraded, as ?OH and ClO?/Cl? shows an affinity towards oxygen-containing organic compounds via single electron transfer by attracting O-H bonds. Especially, carbon/hydrogen/oxygen (CHO-containing) compounds were readily to be degraded with the removal efficiency of 92.5%, 97.0% and 98.4% in electrolysis, ozonation and E+-ozonation, respectively. Moreover, nitrogen atoms have a negative effect on DOM degradation, and thus, carbon/hydrogen/nitrogen and carbon/hydrogen/nitrogen/sulfur (CHN- and CHNS-containing) compounds were considered as refractory compounds. This paper is expected to shed light on the synergetic effect in E+-ozonation and transformation of refractory DOM in CL treatment.Wang, H., Li, H., Sun, K., Huang, H., Zhu, P., Lu, Z., 2020. Impact of exogenous nitrogen on the cyanobacterial abundance and community in oil-contaminated sediment: A microcosm study. Science of The Total Environment 710, 136296. pollution caused by oil spills is a global problem, and outbreaks of blue algae in oil-polluted areas are harmful to plankton in the ocean. The ocean is a barren environment limited by low availabilities of nitrogen and other nutrients, and further nitrogen limitation caused by oil contamination is considered one of the important factors leading to outbreaks of cyanobacteria, but the effects of nitrogen amendment in this situation are not well understood. Here, we present the results from nitrogen amendment experiments conducted in oil-contaminated microcosms. Green mats appeared on the sediment surface of each treatment group at different time points. The appearance of cyanobacterial blooms in the oil-contaminated group supplemented with nitrogen was significantly delayed compared with that in the oil-contaminated group without nitrogen addition. Moreover, oil promoted nitrogen fixation and stimulated the growth of nitrogen-fixing cyanobacteria in the oil-contaminated microcosms. Our results suggest that nitrogen limitation is a vital factor for the induction of cyanobacterial blooms in oil-contaminated environments, and the addition of nitrogen reduced the abundance of cyanobacteria by up to approximately 2.5-fold and slowed the bloom process.Wang, J.-Z., Lei, Y., Xiao, Y., He, X., Liang, J., Jiang, J., Dong, S., Ke, H., Leon, P., Zerbe, P., Xiao, Y., Dehesh, K., 2020. Uncovering the functional residues of Arabidopsi isoprenoid biosynthesis enzyme HDS. Proceedings of the National Academy of Sciences 117, 355-361.: The MEP pathway is an essential and evolutionarily conserved metabolic route present in most pathogenic bacteria, plants, and malaria; and hence a target for discovery of agricultural and medical applications, and an engineering template for production of isoprenoids. The essential nature of this pathway and inherent intricacies associated with enzyme activity assays have hampered in vivo structure and functional analyses. Here, we report the suppressor screen leading to identification of 3 functionally conserved amino-acid residues positioned at the active site cavity and cofactor binding domain of the key MEP-pathway enzyme, HDS. The proposed roles of these residues in determining HDS enzyme activity and the MEP-pathway flux offer a platform for rational design of antiinfective drugs and synthetic engineering of isoprenoids.Abstract: The methylerythritol phosphate (MEP) pathway is responsible for producing isoprenoids, metabolites with essential functions in the bacterial kingdom and plastid-bearing organisms including plants and Apicomplexa. Additionally, the MEP-pathway intermediate methylerythritol cyclodiphosphate (MEcPP) serves as a plastid-to-nucleus retrograde signal. A suppressor screen of the high MEcPP accumulating mutant plant (ceh1) led to the isolation of 3 revertants (designated Rceh1–3) resulting from independent intragenic substitutions of conserved amino acids in the penultimate MEP-pathway enzyme, hydroxymethylbutenyl diphosphate synthase (HDS). The revertants accumulate varying MEcPP levels, lower than that of ceh1, and exhibit partial or full recovery of MEcPP-mediated phenotypes, including stunted growth and induced expression of stress response genes and the corresponding metabolites. Structural modeling of HDS and ligand docking spatially position the substituted residues at the MEcPP binding pocket and cofactor binding domain of the enzyme. Complementation assays confirm the role of these residues in suppressing the ceh1 mutant phenotypes, albeit to different degrees. In vitro enzyme assays of wild type and HDS variants exhibit differential activities and reveal an unanticipated mismatch between enzyme kinetics and the in vivo MEcPP levels in the corresponding Rceh lines. Additional analyses attribute the mismatch, in part, to the abundance of the first and rate-limiting MEP-pathway enzyme, DXS, and further suggest MEcPP as a rheostat for abundance of the upstream enzyme instrumental in fine-tuning of the pathway flux. Collectively, this study identifies critical residues of a key MEP-pathway enzyme, HDS, valuable for synthetic engineering of isoprenoids, and as potential targets for rational design of antiinfective drugs.Wang, J., Song, H., Wang, Y., 2020. Investigation on the micro-flow mechanism of enhanced oil recovery by low-salinity water flooding in carbonate reservoir. Fuel 266, 117156. water flooding has become a significant way to develop carbonate reservoirs in recent years. Clarifying the micro-flow mechanism of low-salinity water flooding (LSWF) on enhanced oil recovery (EOR) becomes the focus of this issue. In this paper, firstly, we conducted a series of experiments to prove that LSWF can improve the recovery of carbonate reservoirs. And then, a new relative permeability model and water content calculation model are established considering interface micro-forces and capillary pressure. The result shows that the present model has good agreement with the experimental results, which can characterize the micro-displacement mechanism of LSWF. The recovery rate can be increased by 9% compared with the formation water flooding (FWF). Under low-salinity conditions, the wettability of rock surface is changed by the chemical reaction of divalent ions (Ca2+, Mg2+, SO42?), which shows more hydrophilic. And the optimal salinity of the brine range from 1400 mg/L to 3200 mg/L. Besides, LSWF can reduce the residual oil saturation, which is the macro cause for EOR. This study has provided a quick and reasonable guide to know the micro-flow mechanism of LSWF and theoretical basis for development of carbonate reservoirs by LSWF.Wang, P., Du, Y., Yu, W., Algeo, T.J., Zhou, Q., Xu, Y., Qi, L., Yuan, L., Pan, W., 2020. The chemical index of alteration (CIA) as a proxy for climate change during glacial-interglacial transitions in Earth history. Earth-Science Reviews 201, 103032. glacial-interglacial transitions of ice ages are associated with large, rapid changes in climate, which potentially can be reconstructed from stratigraphic profiles of the chemical index of alteration (CIA). Here, we present a case study based on high-resolution CIA profiles of Neoproterozoic glacial deposits from South China (paleolatitude ~30° N) as a record of the climate transition at the termination of the Sturtian Glaciation (~663 Ma). Drillcore ZK2115 (Gaodi Deposit) exhibits a progressive upsection increase in mean CIA over a ~50-m interval, from 58 (range 52–65; note: all ranges are given as 16th–84th percentiles) in the synglacial upper Tiesi'ao Formation to 67 (range 64–69) in the deglacial basal Datangpo Formation cap carbonates, and to 68 (range 66–70) in the postglacial Datangpo Formation black shales. A coeval section from the Lijiawan Deposit also exhibits an increasing CIA trend upsection within shallow-water Mn-carbonate facies. These CIA patterns show no relationship to lithology and are interpreted to reflect climatic warming and intensified chemical weathering during the Sturtian deglaciation. Similar large increases in postglacial CIA values are seen in Paleoproterozoic and Late Paleozoic successions, and at least moderate increases in CIA values are recorded during warm stages of the late Quaternary (e.g., the B?lling-Aller?d and Holocene) relative to the cold stages (e.g., the Last Glacial Maximum and Younger Dryas). The rapidity of CIA changes in Quaternary systems (~1 to 10 kyr) suggests that weathering intensity may have changed at similarly rapid rates in more poorly dated deep-time glacial successions, with potential implications for Snowball versus Slushball models of Cryogenian glaciations. These examples show that CIA can be a robust proxy for climate changes (i.e., enhanced chemical weathering intensity) during glacial-interglacial transitions of both ancient and recent ice ages.Wang, Q., Yang, S., Lorinczi, P., Glover, P.W.J., Lei, H., 2020. Experimental investigation of oil recovery performance and permeability damage in multilayer reservoirs after CO2 and water–alternating-CO2 (CO2–wag) flooding at miscible pressures. Energy & Fuels 34, 624-636. in reservoirs caused by asphaltene deposits and inorganic interactions is a serious problem that may exacerbate the complexity of displacement characteristics in heterogeneous multilayer sandstone reservoirs and affect crude oil recovery performance during CO2 and CO2–WAG flooding. In this study, experiments of both CO2 and CO2–WAG flooding were carried out on the same multilayer systems under miscible conditions (70 °C, 18 MPa). The two flooding methods were evaluated for oil production performance and reservoir damage. The experimental results indicate that, after CO2 flooding, the entire system has a low oil recovery factor (RF) of 27.6%, and oil is produced mainly from the high permeability layer (91.4%), while the residual oil remains predominantly in the medium and low permeability layers. The injection pressure of CO2–WAG flooding is high, but the timing of CO2 breakthrough (BT) is late, and the oil RF of the entire system reaches 44.5%. The contribution rate of oil production in medium and low permeability layers is improved to 3.8% and 17.1%, respectively. Furthermore, the permeability of the high permeability layer decreases by 16.8% after CO2 flooding, which is mainly due to asphaltene precipitation. However, after CO2–WAG flooding, the permeability of each layer is significantly reduced, namely by 29.4%, 16.8%, and 6.9%, respectively. Asphaltene precipitation is still the main factor, but permeability decline caused by CO2–brine–rock interactions cannot be ignored, especially in the high permeability layer (6.1%). Therefore, for multilayer reservoirs with high heterogeneity, CO2–WAG flooding provides the better oil displacement performance, but prevention and control measures for asphaltene precipitation are more necessary.Wang, S., Li, S., Du, D., Wang, D., Yan, W., 2020. Conjugative transfer of Megaplasmids pND6–1 and pND6–2 enhancing naphthalene degradation in aqueous environment: characterization and bioaugmentation prospects. Applied Microbiology and Biotechnology 104, 861-871.: Naphthalene catabolic strain Pseudomonas putida ND6 harbors two megaplasmids pND6–1 and pND6–2; naphthalene-degrading associated genes are located on pND6–1, while plasmid pND6–2 possesses potential coding genes for conjugative transfer.Methods: In this study, the recombinant ND6 in which pND6–1 and pND6–2 were labeled with gentamicin and kanamycin-encoding genes, respectively, was constructed to investigate the conjugative transfer behavior of the two plasmids in distinct aqueous matrices.Results: The results indicated that both pND6–1 and pND6–2 plasmids could transfer from donor strain ND6 to a recipient strain P. putida KT2440, while the transfer frequency of pND6–2 (1.90?×?10??2) was significantly higher than that of pND6–1 (3.12?×?10??9). Furthermore, the concomitant transfer of pND6–1 and pND6–2 was confirmed at a lower frequency of 10??9 colonies per recipient similar with that of pND6–1. The conjugative transfer efficiency was obviously affected by the initial inoculum and the stability of microbes. Moreover, more than 90% of the transconjugants lost the plasmids after 20 generations cultivation without resistance pressure, suggesting the importance of selective pressure to maintain the plasmid stability. Finally, the naphthalene degradation analysis by mixed ND6 and KT2440 revealed that conjugative transfer of catabolic plasmids contributed to the rapid dispersion of the degradation genes on plasmids and enhanced the naphthalene removal.Wang, S., Luan, H., Liang, X., Wang, L., Guo, Y., 2020. Recognition and characterization of active fractions from petroleum sulfonate. Journal of Petroleum Science and Engineering 187, 106797. sulfonates are widely used in chemical flooding in China. The samples are complicated and not all the fractions are effective. To recognize effective fraction with excellent interfacial activity and emulsifying property, a preparative liquid chromatography technology was adopted to perform the fraction separation for petroleum sulfonate. Structural composition, interfacial activity，emulsifying property and flooding efficiency of obtained fractions were also analyzed and discussed. It was shown that petroleum sulfonate can be effectively separated into different fractions with obvious structural differences, among which one fraction with the most excellent interfacial activity and the emulsifying property was recognized. The average molecular weight and molecular weight distribution range of this active fraction were 455.5 and 428–468, respectively, which are both crucial for activities. Alkylbenzene dicyclohexane sulfonates, alkyl indan sulfonates, and alkyl naphthalene sulfonates are major structure types, and alkyl chain length is mainly distributed between 12–15, 15–17 and 15–17 respectively. Besides, this active fraction is universal, and it can produce ultralow interfacial tension (~10?3?mN/m) and good emulsifying property against different crude oils including Xinjiang, Changqing, Liaohe Oilfields, etc. in China. The developed technology herein can be used to track and confirm the characteristics and/or active fraction in petroleum sulfonate accurately.Wang, T., Cheng, X., Xu, H., Meng, Y., Yin, Z., Li, X., Hang, W., 2020. Perspective on advances in laser-based high-resolution mass spectrometry imaging. Analytical Chemistry 92, 543-553. spectrometry imaging (MSI) has become a powerful tool in diverse fields, such as chemistry, physics, materials, and life science. Although such research is getting more prevalent, it is limited by high-resolution (HR) instrumental development. Recently, unceasing efforts have been made toward taking spatial resolution from the microscale to nanoscale, especially for near-field based techniques. These emerging and unique features behind high-resolution mass spectrometry imaging (HR-MSI) provide new possibilities in various aspects of biological researches. Since many technological advances provided a forefront for HR-MSI, compelling challenges including sensitivity, specificity, multimodal imaging, data acquisition, and processing follow undoubtedly. Gratifyingly, with attempts and experiences in the infancy, the emerging techniques move toward much more mature to deal with underlying conundrums in the future. Not only confined to commercial instruments, this perspective highlights recent innovations covering all emerging HR-MSI (with spatial resolution below 5 μm) techniques. Besides, vital limitations and handicaps at this stage are presented while corresponding schemes are proposed. This perspective also gives the authors’ personal outlooks of developments and applications for HR-MSI in coming years.Wang, X., Jiang, Z., Jiang, S., Chang, J., Li, X., Wang, X., Zhu, L., 2020. Pore evolution and formation mechanism of organic-rich shales in the whole process of hydrocarbon generation: Study of artificial and natural shale samples. Energy & Fuels 32, 332-347. pore evolution has a dramatic influence on gas occurrence and is of great significance for the evaluation of gas shale reservoirs. To better understand the nanopore evolution during the whole hydrocarbon generation process, thermal simulation experiment, gas adsorption (N2 and CO2), and organic geochemistry experiments were carried out. The results show that total pore volume (PV) and specific surface area (SSA) exist in two favorable development periods during the whole hydrocarbon generation process with corresponding vitrinite reflectance (Ro) values of ～1.5–1.8% and ～2.5–3.2%, respectively, which are two peak periods of porosity development. In the two hydrocarbon generation intervals, primary organic matter (OM) and secondary OM crack to gases accompanied by the formation of OM-hosted pores in large quantities, resulting in the increase of porosity. Shale pore formation and evolution are dominantly controlled by hydrocarbon generation as well as diagenesis. Compaction and cementation exert destructive influences on mineral associated pores, especially in the relatively early diagenesis process, resulting in a great decrease of total porosity. Infilling of secondary OM to inorganic interparticle pores also results in the destruction of porosity. OM-hosted pores are documented as a function of thermal maturity, which is significantly related to kerogen and secondary OM cracking to hydrocarbon.Wang, X., Li, W., Zhang, B., Pei, S., Chen, Z., 2019. The formation mechanisms of ultra-tight and overpressured gas reservoir in the third Member of Upper Triassic Xujiahe Formation in the northwestern Sichuan Basin. Natural Gas Industry 39, 25-35. Chinese. More studies have been carried out on the tight and overpressured gas reservoir of the Upper Triassic Xujiahe Formation in the northwestern Sichuan Basin, but the formation mechanisms of tight reservoir, the distribution characteristics and formation mechanisms of abnormal ultra-high pressure and the effects of thermal evolution on large-scale tight gas accumulation have not been researched systematically and thoroughly. To this end, this paper studied the reservoir characteristics and main controlling factors of the third Member of Xujiahe Formation(Xu 3 Member for short) in this area using a large quantity of drilling data obtained recently. And combined with the thermal evolution of the source rocks and the evolution of diagenesis, the reasons for the formation of tight reservoir were analyzed. Then, the formation mechanisms of overpressured gas reservoirs were studied based on tectonic movement after the temperature and pressure characteristics of the fluids in gas reservoirs were analyzed. Finally, the mechanisms of large-scale overpressured natural gas accumulation were analyzed after the characteristics of large-scale overpressured gas reservoirs were summarized. And the following research results were obtained. First, ultra-tight reservoir of Xu 3 Member is the product under the joint effect of strong diagenetic compaction and strong calcareous cementation caused by a large amount of carbonate debris in sediments. Second, the Xu 3 Member reservoir has experienced high thermal evolution in great burial depth. The tightest reservoir is the area with the highest thermal evolution and also the main tight gas development area. The formation of ultra-high pressure tight gas reservoir is obviously affected by the strong diagenesis and the high thermal evolution in the late Cretaceous period. Third, in Jian’ge area, the diagenetic compaction of Xu 3 Member sandstone/glutenite leads to the reduction of porosity by 20%. The important reason for the reservoir densification caused by carbonate cementation is that Anxian tectonic movement leads to the uplifting of Longmenshan Mountain, providing sufficient sources of carbonate rocks for the deposit of Xujiahe Formation. And consequently, the porosity is reduced by 10-20%. Fourth, the formation of abnormal high pressure gas reservoir in the depression zone of this area is not caused by structural compression, but by poor pressure release resulted from fracture underdevelopment, hydrocarbon generation pressurization and tectonic reversal, which leads to the formation of an ultra-high pressure development zone of ultra-tight reservoir. The fracture development in the front margin of Longmenshan and Micangshan fault belts leads to pressure release, so it is a normal pressure zone, whose reservoir physical properties are better than those of the depression zone. It is concluded that the formation mechanisms of large-scale ultra-high pressure tight gas reservoirs in this area are complex with various influencing factors, and the close source-reservoir assemblage relationship, the high thermal evolution and hydrocarbon generation pressurization in the late Cretaceous, the tectonic reversal and stratigraphic uplift and erosion in the Himalayan period, the poor pressure release of ultra-tight reservoir caused by the excellent sealing ability of surrounding rock play a significant role in the large-scale accumulation of abnormal ultra-high pressure natural gas in this area.Wang, X., Liu, L., Wang, Y., Sheng, Y., 2019. High-pressure isothermal methane adsorption characteristic of Longmaxi Formation shale in the southern Sichuan Basin. Natural Gas Industry 39, 32-39. Chinese. Accurate determination of gas content in shale is of great significance to the evaluation and the exploitation of shale gas reservoirs. At present, however, domestic and foreign scholars have different opinions on the model selection, adsorption mode and adsorption characteristics parameter in the isothermal adsorption experiment of shale methane, and the high-pressure isothermal methane adsorption characteristics are less researched. In this paper, the structural characteristics of the pores in the shale of Lower Silurian Longmaxi Formation were analyzed by conducting N2/CO2 low-pressure isothermal adsorption experiments. Then, gravimetric high-pressure isothermal methane adsorption experiments were carried out, and three different adsorption models（SDR, Langmuir and BET） were used to calculate the content of adsorbed methane. Finally, the methane adsorption characteristics of the samples were researched. And the following research results were obtained. First, as for the pores with a size of 0–50 nm, the distribution of specific surface area and pore volume is bimodal and trimodal, respectively. Compared with mesopores, micropores are higher in specific surface area and lower in pore volume and heterogeneity（D1<D2）. Second, among the SDR, Langmuir and BET models, the average error of the first two models is both less than 6%. And methane molecules coexist in shale pores mainly in the adsorption form of monomolelcular layers and micropore filling. Third, in the case of high pressure and great burial depth, temperature is the main factor affecting the adsorption capacity and density of adsorbed methane. In the meantime, the density of the absorbed methane is also affected by thermodynamic parameter, pore structure and heterogeneity. Fourth, methane molecules are mainly adsorbed in the micropores（0.4–0.8 nm） with higher absorption energy and larger specific area in the form of monomolecular layer in a low-pressure phase, and then most of them are adsorbed in micropores and mesopores（1.4–8.0 nm） in the coexistence form of micropore filling and monomolecular layer. In the high-pressure phase, few methane molecules are absorbed in mesopores and macropores in the pattern of multi-molecular layers.Wang, Y., Lian, J., Xue, Y., Liu, P., Dai, B., Lin, H., Han, S., 2020. The pyrolysis of vitrinite and inertinite by a combination of quantum chemistry calculation and thermogravimetry-mass spectrometry. Fuel 264, 116794. this study, pyrolysis behaviour of vitrinite and inertinite from Heidaigou long-flame coal was studied via quantum chemical calculation and TG-MS. Quantum chemical calculation showed that vitrinite contains bonds with long bond length and small bond order, whereas inertinite revealed the opposite. And vitrinite and inertinite presented the same order of breaking bonds, but the numbers of breaking bonds showed differences. Before CO2 release, bond breakages and initial breakdown of macromolecular structure were observed. TG-MS analysis showed that the emissions with the same number of carbon, whether from vitrinite pyrolysis or inertinite pyrolysis, showed the same variation trend. Emissions from both vitrinite and inertinite can be divided into following four types. The first includes CO2, which was detected at 300 °C. The second consists of C1, C2, C3 and C4 compounds, which were observed at 420 °C and showed a fast release rate. The third comprises C6 and C7 compounds and CO, which were also detected at 420 °C with a slow release rate, and the fourth includes H2, which was identified at 500 °C. The escapes of the same substances during pyrolysis of vitrinite and inertinite were compared. Almost all emissions from vitrinite were higher than those from inertinite, but the temperature of maximum CO2 release from vitrinite was lower than that of inertinite.Wang, Z., Chen, C., Wang, J., Suess, E., Chen, X., Ma, X., Wang, G., Xiao, S., 2020. Wide but not ubiquitous distribution of glendonite in the Doushantuo Formation, South China: Implications for Ediacaran climate. Precambrian Research 338, 105586. are pseudomorphs of syndepositional or early authigenic ikaite (CaCO3·6H2O) that often forms at near-freezing temperatures. Silicified glendonite has been reported from inner-shelf deposits of the lower Ediacaran Doushantuo Formation at a single stratigraphic section in South China, where they are stratigraphically associated with the positive δ13C excursion EP1 but predate the negative δ13C excursion EN3 (=Shuram excursion), indicating a period of cool climate somewhere between ~609 Ma and ~551 Ma. This interpretation predicts a wider geographic distribution of Ediacaran glendonites in equivalent strata in the Yangtze Block of South China. To test this prediction, we conducted a regional survey of Doushantuo Formation and found that, although glendonites are not universally present, they occur in expected stratigraphic intervals and in association with EP1 at two new sections representing inner-shelf and intrashelf basin facies. The wide but not ubiquitous distribution of Doushantuo glendonites indicates that ikaite precipitation and glendonite formation was controlled by both regional climatic and local geochemical factors. Glendonites at the new localities are stellate clusters pseudomorphed by calcite spar and sometimes are rimmed with silica. The calcite spar is characterized by highly variable and mostly negative δ13C values as low as ?37‰, indicating that diagenetic transformation of precursor ikaite to calcitic glendonite may be related to anaerobic oxidation of organic matter or methane in sediment. The new data suggest an early Ediacaran cold period prior to EN3 or the Shuram excursion and facilitation of glendonite/ikaite formation by both climatic and local geochemical conditions such as redox conditions and phosphate concentrations.Wang, Z., Nelson, D.D., Dettman, D.L., McManus, J.B., Quade, J., Huntington, K.W., Schauer, A.J., Sakai, S., 2019. Rapid and precise analysis of carbon dioxide clumped isotopic composition by tunable infrared laser differential spectroscopy. Analytical Chemistry 92, 2034-2042. high precision measurement of doubly substituted (“clumped”) isotopologues in CO2 is a topic of significant interest in isotope geochemistry. Here we describe the performance of a new isotope ratio laser spectrometer using tunable infrared laser differential absorption spectroscopy (TILDAS). The TILDAS instrument has two continuous-wave lasers to simultaneously measure the four isotopologues involved in the 12C16O2 + 13C16O18O ? 13C16O2 + 12C16O18O exchange reaction. CO2 samples are trapped in a low volume (～250 mL) optical multipass cell with a path length of 36 m. Each sample is compared to a reference gas, and clumped isotopologue precision of 0.01‰ (SE) is achieved within 20 min for 15 μmol samples. Similar precision is also achieved for bulk isotopic composition. The degree of rare isotope clumping in excess of strictly random distribution (Δ16O13C18O) measured by this TILDAS instrument varies linearly with theoretically calculated values and shows a very weak dependence on bulk isotopic composition.Weber, A.L., Rios, A.C., 2019. Imidazolium-catalyzed synthesis of an imidazolium catalyst. Origins of Life and Evolution of Biospheres 49, 199-211. chemistry of imidazolium-catalyzed imidazolium synthesis was studied as part of an effort to develop a plausible prebiotic synthesis of a small catalytic molecule capable of catalyzing its own synthesis. Specifically, we investigated the one-pot 1-ethyl-3-methylimidazolium acetate (EMIM-Ac) catalyzed synthesis of 1,3-dibutyl-4,5-difuryl-imidazolium acetate (DBDFIM-Ac) from furfural, n-butylamine, formaldehyde, and acetic acid at 80?°C. Liu et al. (2012) had previously demonstrated the first reaction of the synthetic process, the EMIM-Ac catalyzed benzoin condensation of furfural that yields furoin. Our early studies established the second reaction of the synthetic process, the multicomponent reaction of furoin, n-butylamine, formaldehyde, and acetic acid that yields the imidazolium salt, DBDFIM-Ac. Studies of the complete two-reaction process that uses furfural for the synthesis of DBDFIM-Ac showed that the highest yield of DBDFIM-Ac was obtained when the mole ratio of n-butylamine, formaldehyde, and acetic acid relative to furfural was respectively (0.5:0.25:0.25:1.0-furfural), or one-half of the stoichiometric ratio (1.0:0.5:0.5:1.0-furfural). A time course study of the process showed transient formation of furoin, the obligatory reaction intermediate. DBDFIM-Ac and the imidazolium side product, 1,3-dibutyl-4,5-trifuryl-imidazolium acetate (DBTFIM-Ac), were stable under the reaction conditions. Imidazolium products (DBDFIM and DBTFIM) and the furoin intermediate were not formed in control reactions (80?°C, 24?h) in which EMIM catalyst was either absent or replaced with an equal volume of acetonitrile or DMF. The imidazolium product, DBDFIM-Ac, was shown to catalyze the synthesis of structurally similar 1,3-dipentyl-4,5-difuryl-imidazolium acetate (DPDFIM-Ac) from furfural, n-pentylamine, formaldehyde, and acetic acid at 80?°C.Wei, S., Han, G., Chu, X., Song, W., He, W., Xia, J., Wu, H., 2020. Effect of tidal flooding on ecosystem CO2 and CH4 fluxes in a salt marsh in the Yellow River Delta. Estuarine, Coastal and Shelf Science 232, 106512. flooding is the basic hydrological feature of a salt marsh, and controls its ecosystem carbon exchange. However, the response of ecosystem carbon exchange to different stages of tidal flooding remains poorly documented. To further explore this issue, we conducted a field experiment to assess the effect of tidal stages (before flooding stage, rising tide stage, tidal flooding stage and after ebbing stage), water levels (a control, a low water level (LWL), a middle water level (MWL) and a high water level (HWL)) and soil salinity on ecosystem CO2 and CH4 fluxes in a salt marsh in the Yellow River Delta. Our results showed that the rising tide stage significantly inhibited the uptake of CO2 (LWL: 1.49 ± 0.23 μmol m?2 s?1; MWL: 1.10 ± 0.35 μmol m?2 s?1; HWL: 0.54 ± 0.08 μmol m?2 s?1). Meanwhile, the rising tide stage also promoted CH4 emissions of MWL and HWL treatments (MWL: 0.97 ± 0.36 nmol m?2 s?1; HWL: 0.93 ± 0.24 nmol m?2 s?1). CH4 emissions of the after ebbing stage was higher than that of the before flooding stage, and this difference was significant of LWL and MWL treatments (LWL: 0.56 ± 0.12 vs 0.38 ± 0.09 nmol m?2 s?1; MWL: 0.79 ± 0.13 vs 0.40 ± 0.09 nmol m?2 s?1). Moreover, ecosystem CO2 exchange of the HWL treatment was almost completely suppressed during tidal inundation period. During tidal inundation period, net ecosystem CO2 exchange (NEE) was significantly positively correlated with water levels, but CH4 emissions was not significantly affected by water levels. In addition, the rate of CO2 uptake decreased linearly with soil salinity during the non-inundation period. Therefore, it is necessary to analyze the carbon exchange process coupling with the complete tidal flooding process in future researches.Wendruff, A.J., Babcock, L.E., Wirkner, C.S., Kluessendorf, J., Mikulic, D.G., 2020. A Silurian ancestral scorpion with fossilised internal anatomy illustrating a pathway to arachnid terrestrialisation. Scientific Reports 10, 14. are among the first animals to have become fully terrestrialised. Their early fossil record is limited, and fundamental questions, including how and when they adapted to life on land, have been difficult to answer. Here we describe a new exceptionally preserved fossil scorpion from the Waukesha Biota (early Silurian, ca. 437.5–436.5?Ma) of Wisconsin, USA. This is the earliest scorpion yet reported, and it shows a combination of primitive marine chelicerate and derived arachnid characteristics. Elements of the circulatory, respiratory, and digestive systems are preserved, and they are essentially indistinguishable from those of present-day scorpions but share similarities with marine relatives. At this early point in arachnid evolution, physiological changes concomitant with the marine-to-terrestrial transition must have occurred but, remarkably, structural change in the circulatory or respiratory systems appear negligible. Whereas there is no unambiguous evidence that this early scorpion was terrestrial, this evidence suggests that ancestral scorpions were likely capable of forays onto land, a behavior similar to that of extant horseshoe crabs.Williams, T.A., Cox, C.J., Foster, P.G., Sz?ll?si, G.J., Embley, T.M., 2020. Phylogenomics provides robust support for a two-domains tree of life. Nature Ecology & Evolution 4, 138-147. about the origin of eukaryotic cells are classically framed within the context of a universal ‘tree of life’ based on conserved core genes. Vigorous ongoing debate about eukaryote origins is based on assertions that the topology of the tree of life depends on the taxa included and the choice and quality of genomic data analysed. Here we have reanalysed the evidence underpinning those claims and apply more data to the question by using supertree and coalescent methods to interrogate >3,000 gene families in archaea and eukaryotes. We find that eukaryotes consistently originate from within the archaea in a two-domains tree when due consideration is given to the fit between model and data. Our analyses support a close relationship between eukaryotes and Asgard archaea and identify the Heimdallarchaeota as the current best candidate for the closest archaeal relatives of the eukaryotic nuclear lineage.Windirsch, T., Grosse, G., Ulrich, M., Schirrmeister, L., Fedorov, A.N., Konstantinov, P.Y., Fuchs, M., Jongejans, L.L., Wolter, J., Strauss, J., 2020. Organic carbon characteristics in ice-rich permafrost in Alas and Yedoma deposits, Central Yakutia, Siberia. Biogeosciences Discussions 2020, 1-31. ground is one of the largest repositories of stored terrestrial natural carbon and might become a carbon source with ongoing global warming. In particular, syngenetically frozen ice-rich Yedoma deposits originating from the late Pleistocene store a large amount of carbon. This carbon has not yet become part of the recent carbon cycle. With this study of Yedoma and associated Alas deposits in Central Yakutia we aim to understand the local sediment genesis and its effect on permafrost carbon storage. For this purpose, we investigated the Yukechi Alas area (61.76495°?N, 130.46664°?E), a thermokarst landscape degrading into Yedoma in Central Yakutia. Two sediment cores (Yedoma upland, 22.35?m depth, and Alas basin, 19.80?m depth) were drilled in 2015. We analyzed for ice content, total carbon and total nitrogen content, total organic carbon content, stable oxygen and hydrogen isotopes, stable carbon isotopes, mass specific magnetic susceptibility, grain size distribution, and radiocarbon ages. Samples taken from both cores were radiocarbon-dated up to 50,000 years before present. The laboratory analyses of both cores revealed very low carbon contents down to several meters depth. Those core parts holding very little to no detectable carbon consist of coarser sandy material estimated to an age between 39,000 and 18,000 years before present. For this period we assume sediment input of organic-poor material. Water isotope data derived from pore ice within the Yedoma core indicate a continuously cold state of the lower core parts, thereby ruling out a potential theory of Holocene influence. In consequence, we conclude that no strong organic matter decomposition took place in the sediments of the Yedoma core until today. In contrast, the Alas core from an adjacent thermokarst basin was strongly disturbed by lake development and permafrost thaw, and accordingly its sediment and carbon characteristics differed from those of the Yedoma core. The Alas core shows homogeneous ice content and the water isotope characteristics of a slightly more decomposed organic material; the findings of very carbon-poor core sections from the Yedoma core can be duplicated. The Yedoma deposition was likely influenced by fluvial regimes in nearby streams and the Lena River shifting with climate. The low carbon content and the clear stratigraphical layering of different sediment types suggest that the Yedoma deposits in the Yukechi area differ from other Yedoma sites regarding carbon stock and sedimentological composition. We conclude that sedimentary composition and deposition regimes of Yedoma may differ significantly within the Yedoma domain. The resulting heterogeneity should be taken into account for upscaling approaches on the Yedoma carbon stock. The Alas core gives clear insights into the future development of Cenral Yakutian Yedoma deposits.Wisen, J., Chesnaux, R., Werring, J., Wendling, G., Baudron, P., Barbecot, F., 2020. A portrait of wellbore leakage in northeastern British Columbia, Canada. Proceedings of the National Academy of Sciences 117, 913-922.: The possibility of leakage from oil and gas wells has raised environmental concerns. There are 2 major environmental consequences of wellbore leakage: 1) the risk of groundwater contamination from hydrocarbons and brines and 2) the risk of greenhouse gas (GHG) emissions. In this study, oil and gas wellbore leakage data from British Columbia (BC) were analyzed in order to quantify the occurrence and pathways of leakage as well as the contribution to GHG emissions. The key results summarize as follows. 1) In total, 2,329 wells in BC (of 21,525 that have been tested for leakage) have had reported leakage during the lifetime of the well. 2) In total, GHG emissions are estimated to reach about 75,000 metric t/y. The study also underlines that the values of leaky wells are likely underreported.Abstract: Oil and gas well leakage is of public concern primarily due to the perceived risks of aquifer contamination and greenhouse gas (GHG) emissions. This study examined well leakage data from the British Columbia Oil and Gas Commission (BC OGC) to identify leakage pathways and initially quantify incident rates of leakage and GHG emissions from leaking wells. Three types of leakage are distinguished: “surface casing vent flow” (SCVF), “outside the surface casing leakage” (OSCL), and “cap leakage” (CL). In British Columbia (BC), the majority of reported incidents involve SCVF of gases, which does not pose a risk of aquifer contamination but does contribute to GHG emissions. Reported liquid leakage of brines and hydrocarbons is rarer. OSCL and CL of gas are more serious problems due to the risk of long-term leakage from abandoned wells; some were reported to be leaking gas several decades after they were permanently abandoned. According to the requirements of provincial regulation, 21,525 have been tested for leakage. In total, 2,329 wells in BC have had reported leakage during the lifetime of the well. This represents 10.8% of all wells in the assumed test population. However, it seems likely that wells drilled and/or abandoned before 2010 have unreported leakage. In BC, the total GHG emission from gas SCVF is estimated to reach about 75,000 t/y based on the existing inventory calculation; however, this number is likely higher due to underreporting.Wolbach, W.S., Ballard, J.P., Mayewski, P.A., Kurbatov, A., Bunch, T.E., LeCompte, M.A., Adedeji, V., Israde-Alcántara, I., Firestone, R.B., Mahaney, W.C., Melott, A.L., Moore, C.R., Napier, W.M., Howard, G.A., Tankersley, K.B., Thomas, B.C., Wittke, J.H., Johnson, J.R., Mitra, S., Kennett, J.P., Kletetschka, G., West, A., 2020. Extraordinary biomass-burning episode and impact winter triggered by the younger Dryas cosmic impact ～12,800 years ago: A reply. The Journal of Geology 128, 95-107. hypotheses with major multidisciplinary implications, such as the Younger Dryas airburst/impact hypothesis, appropriately face intense testing, and we respect that. However, such criticisms must be based on facts. Instead, many of the assertions made in the discussion by Holliday and coauthors are inaccurate. In this article, we present rebuttals of the most significant of their inaccurate assertions but decline to address unfounded opinions. Most of the following discussion deals with the implications of the Younger Dryas Boundary (YDB) layer, including evidence supporting extensive YDB burning and its proposed age, identification, and context within the chronological record. Other issues include the association of biomass burning with impact-related proxies, megafaunal extinctions, and human population declines. Holliday and coauthors dispute whether impacts, in general, can even cause biomass burning, a long-settled question. These issues are presented mostly in order of appearance with direct quotations from the discussion by Holliday and coauthors in boldface type within quotation marks. Emphasis has been added to some of their statements, as noted.Reply to: Holliday, V.T., Bartlein, P.J., Scott, A.C., Marlon, J.R., 2020. Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ～12,800 years ago, Parts 1 and 2: A discussion. The Journal of Geology 128, 69-94.Original Papers: Wolbach, W.S., Ballard, J.P., Mayewski, P.A., Adedeji, V., Bunch, T.E., Firestone, R.B., French, T.A., Howard, G.A., Israde-Alcántara, I., Johnson, J.R., Kimbel, D., Kinzie, C.R., Kurbatov, A., Kletetschka, G., LeCompte, M.A., Mahaney, W.C., Melott, A.L., Maiorana-Boutilier, A., Mitra, S., Moore, C.R., Napier, W.M., Parlier, J., Tankersley, K.B., Thomas, B.C., Wittke, J.H., West, A., Kennett, J.P., 2018. Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ～12,800 years ago. 1. Ice cores and glaciers. The Journal of Geology 126, 165-184.Wolbach, W.S., Ballard, J.P., Mayewski, P.A., Parnell, A.C., Cahill, N., Adedeji, V., Bunch, T.E., Domínguez-Vázquez, G., Erlandson, J.M., Firestone, R.B., French, T.A., Howard, G., Israde-Alcántara, I., Johnson, J.R., Kimbel, D., Kinzie, C.R., Kurbatov, A., Kletetschka, G., LeCompte, M.A., Mahaney, W.C., Melott, A.L., Mitra, S., Maiorana-Boutilier, A., Moore, C.R., Napier, W.M., Parlier, J., Tankersley, K.B., Thomas, B.C., Wittke, J.H., West, A., Kennett, J.P., 2018. Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact ～12,800 years ago. 2. Lake, marine, and terrestrial sediments. The Journal of Geology 126, 185-205.Woulds, C., Bell, J.B., Glover, A.G., Bouillon, S., Brown, L.S., 2020. Benthic carbon fixation and cycling in diffuse hydrothermal and background sediments in the Bransfield Strait, Antarctica. Biogeosciences 17, 1-12. hydrothermal vents are likely to be widespread compared to hard substrate hot vents. They host chemosynthetic microbial communities which fix inorganic carbon (C) at the seafloor, as well as a wide range of macroinfauna, including vent-obligate and background non-vent taxa. There are no previous direct observations of carbon cycling at a sedimented hydrothermal vent. We conducted 13C isotope tracing experiments at three sedimented sites in the Bransfield Strait, Antarctica, which showed different degrees of hydrothermalism. Two experimental treatments were applied, with 13C added as either algal detritus (photosynthetic C), or as bicarbonate (substrate for benthic C fixation). Algal 13C was taken up by both bacteria and metazoan macrofaunal, but its dominant fate was respiration, as observed at deeper and more food-limited sites elsewhere. Rates of 13C uptake and respiration suggested that the diffuse hydrothermal site was not the hot spot of benthic C cycling that we hypothesised it would be. Fixation of inorganic C into bacterial biomass was observed at all sites, and was measurable at two out of three sites. At all sites, newly fixed C was transferred to metazoan macrofauna. Fixation rates were relatively low compared with similar experiments elsewhere; thus, C fixed at the seafloor was a minor C source for the benthic ecosystem. However, as the greatest amount of benthic C fixation occurred at the “Off Vent” (non-hydrothermal) site (0.077±0.034?mg?C?m?2 fixed during 60?h), we suggest that benthic fixation of inorganic C is more widespread than previously thought, and warrants further study.Wu, Q., Wang, J.-Y., Han, D.-Q., Yao, Z.-P., 2020. Recent advances in differentiation of isomers by ion mobility mass spectrometry. TrAC Trends in Analytical Chemistry 124, 115801. of isomers is an important analytical task in many fields, e.g., chemistry, biology, pharmaceutical science, medicine, environmental science, food science. Ion mobility mass spectrometry (IM-MS) can resolve isobaric ions based on their shape and size and measure the collision cross section (CCS) values of ions to provide information on their intrinsic structures, and is thus a very promising tool for differentiation of isomers. In this review, the applications of IM-MS in differentiation of various isomers including glycans, lipids, amino acids, peptides, proteins, as well as metabolite isomers, chiral isomers, etc. are summarized. Prospects for further development of IM-MS for differentiation of isomers, e.g., improved resolving powers of IM-MS instruments and measurement reproducibility, expanded CCS database and coupling of IM-MS with computational approaches, are also discussed.Xavier, J.C., 2020. The early origin of cooperation. Nature Ecology & Evolution 4, 18-19. physical linkage of the first self-replicating molecules is likely to have been selected based on their capacity to perform cooperative catalysis.Xia, J.-M., Hu, X.-M., Huang, C.-H., Yu, L.-B., Xu, R.-F., Tang, X.-X., Lin, D.-H., 2020. Metabolic profiling of cold adaptation of a deep-sea psychrotolerant Microbacterium sediminis to prolonged low temperature under high hydrostatic pressure. Applied Microbiology and Biotechnology 104, 277-289. most wide-spread “hostile” environmental factor for marine microorganisms is low temperature, which is usually accompanied by high hydrostatic pressure (HHP). Metabolic mechanisms of marine microorganisms adapting to prolonged low temperature under HHP remain to be clarified. To reveal the underlying metabolic mechanisms, we performed NMR-based metabolomic analysis of aqueous extracts derived from a psychrotolerant Microbacterium sediminis YLB-01, which was isolated from deep-sea sediment and possess great biotechnology potentials. The YLB-01 cells were firstly cultivated at the optimal condition (28?°C, 0.1?MPa) for either 18?h (logarithmic phase) or 24?h (stationary phase), then continually cultivated at either 28?°C or 4?°C under HHP (30?MPa) for 7?days. The cells cultivated at low temperature, which experienced cold stress, were distinctly distinguished from those at normal temperature. Cold stress primarily induced metabolic changes in amino acid metabolism and carbohydrate metabolism. Furthermore, the logarithmic and stationary phase cells cultivated at low temperature exhibited distinct metabolic discrimination, which was mostly reflected in the significantly disturbed carbohydrate metabolism. The logarithmic phase cells displayed suppressed TCA cycle, while the stationary phase cells showed decreased pyruvate and increased lactate. In addition, we performed transcriptome analysis for the stationary phase cells to support the metabolomic analysis. Our results suggest that the cold adaptation of the psychrotroph YLB-01 is closely associated with profoundly altered amino acid metabolism and carbohydrate metabolism. Our work provides a mechanistic understanding of the metabolic adaptation of marine psychrotrophs to prolonged low temperature under HHP.Xia, L., Yang, J., Su, R., Zhou, W., Zhang, Y., Zhong, Y., Huang, S., Chen, Y., Li, G., 2020. Recent progress in fast sample preparation techniques. Analytical Chemistry 92, 34-48. preparation prior to instrument analysis plays a significant role in whole analytical process. In modern analytical chemistry, samples with wide varieties and high complexity are receiving increasing attention, which probably contain multiple target analytes and a complex matrix. Moreover, these target analytes may be extremely similar to each other but present a trace amount in the sample matrix. Thus, to eliminate matrix interference, extraction and separation of target analytes as well as concentration of trace level compounds must be accomplished before instrument analysis. Theoretically, sample preparation is the procedure of transferring analytes from a sample matrix to qualitative and quantitative evaluation with better applicability by their differences in the physical, chemical, and biological properties. From chaos to order, this mass transfer procedure cannot occur automatically. Essentially, sample preparation is dealing with how to maximize the spontaneous process of the second law of thermodynamics in the opposite direction. In other words, to achieve enough or even better efficiency of sample preparation, including separation and enrichment processes, additional energy or reduced entropy have to be applied into the mass transfer system. Beyond producing work, changing the distribution of chemical potential in the system, which is caused by the introduction of phase, membrane, and field, turns out to be an alternative approach to reduce system entropy and improve the sample preparation efficiency. Therefore, sample preparation is an important but probably the most time-consuming and labor-intensive part of sample analysis. However, with the development of rapid and sensitive detection systems, accelerating the sample preparation becomes the bottleneck of rapid sample analysis. For example, in point-of-care tests, novel sample pretreatment methods and devices are highly desired to obtain results in a very short of period with acceptable accuracy.(1,2) Practically, four approaches can be used to cut down the time consumed in sample preparation. First, introduction of additional energy into the preparation process can help to accelerate mass transfer and heat exchange. By employing an assisting field, including acoustic wave, microwave, and electrical field, the speed and efficiency of sample preparation can be improved. Second, speeding up mass transfer in the sample preparation process can be realized by adding materials. Four classical materials-based acceleration methods might be used for fast sample preparation; they are phase adsorption or partition, chemical transformation, sized-based recognition, and mass transfer acceleration. Third, size reduction of the sample is a direct way to shorten the period of time needed in preparation procedures. For instance, in electrophoretic separation, less sample injection provides rapid baseline separation.(3,4) Unfortunately, the most commonly used sample preparation devices either cannot handle sample in vary small amounts or suffer from the damage on assay sensitivity and accuracy. This shortcoming is addressed by device miniaturization techniques very well, including microextraction and microfluidics. Fourthly, employing appropriate integration strategies is another useful approach. To simultaneously accomplish preparation procedures for a batch of samples, high-throughput assays could reduce the average preparation period for each sample. In other cases, several preparation procedures were realized in a single step or automatically. In this review, a comprehensive survey on progress in fast sample preparation in the last 2 years has been composed from more than 180 references, and we highlight the most useful acceleration approaches for sample preparation: they are energy exchange, materials, size reduction, and integration.Xiao, W., Xu, Y., Haghipour, N., Montlu?on, D.B., Pan, B., Jia, Z., Ge, H., Yao, P., Eglinton, T.I., 2020. Efficient sequestration of terrigenous organic carbon in the New Britain Trench. Chemical Geology 533, 119446. fate of terrigenous organic carbon (OCterr) in the ocean remains an enigma for four decades. Hadal trenches, the deepest ocean realm (6–11 km deep), were recently proposed to be OC depocenters, but whether and how much OCterr was sequestrated there remain elusive. Here we conducted comprehensive analyses for four sediment cores from the New Britain Trench (NBT) close to Papua New Guinea to assess source, translocation and burial of OC. The bulk and molecular radiocarbon data suggest that the NBT landward slope and axis sediments mainly receive young and biogenic rather than petrogenic OC. The three-endmember mixing model based on Δ14C, δ13C and OC contents reveals that sediments of the NBT axis (8225 m) comprise relatively high OC contents (0.66 ± 0.08%), of which biogenic OCterr accounts for 62 ± 10%. The high proportion of biogenic OCterr was attributed to the selective translocation of OCterr-enriched coarse particles and rapid delivery of sediments supported by unique V-shape feature of the trench. In contrast, the sediment OC at the oceanward slope is primarily of a marine origin, suggesting that OCterr was efficiently trapped in the trench bottom. It is estimated that the burial rate is 2.75 ± 0.32 g C m?2 yr?1 for OC and 1.69 ± 0.41 g C m?2 yr?1 for OCterr in the NBT. Given a fact that many trenches are close to the landmasses, we propose that the hadal trenches may contribute significantly to the burial of OCterr in the ocean.Xie, S.-M., Chen, X.-X., Zhang, J.-H., Yuan, L.-M., 2020. Gas chromatographic separation of enantiomers on novel chiral stationary phases. TrAC Trends in Analytical Chemistry 124, 115808. capillary gas chromatography has been widely applied to separate volatile and thermally stable enantiomers due to its advantages of simplicity, high efficiency, fast analysis, good sensitivity, and absence of liquid mobile phases. In the first part of this article, recent research progress (from 2010 to the present) concerning newly developed chiral stationary phases based on cyclofructan derivatives and chiral porous materials, including metal-organic frameworks, covalent organic frameworks, inorganic mesoporous silicas, and molecular cages for use in gas chromatography, and the synthetic strategies for obtaining chiral porous materials, was reviewed. Finally, we discussed in detail the separation performances and chiral recognition mechanisms of novel chiral recognition materials coated on capillary columns towards various types of enantiomers, namely (1) amino acid derivatives; (2) alcohols, amines, and amino alcohols; (3) organic acids; (4) aldehydes and ketones; (5) ethers and epoxides, and (6) esters and other enantiomers.Xu, H., 2020. Probing nanopore structure and confined fluid behavior in shale matrix: A review on small-angle neutron scattering studies. International Journal of Coal Geology 217, 103325. continued growth in unconventional oil and gas production is generally projected, its long-term growth potential and sustainability have significant uncertainties. A critical problem is the low hydrocarbon recovery rates from shale and other tight formations using the horizontal well drilling and hydraulic fracturing techniques: < 10% for tight oil and ~ 20% for shale gas. Moreover, the production rate for a given well typically declines rapidly within one year. The low recoveries and declining production of shale oil and gas reservoirs are apparently related to the small porosity (a few to a few hundred nm) and low permeability (10?16–10?20?m2) of shale matrix, which make the enclosed hydrocarbon fluids difficult to access. Hence, to enhance the hydrocarbon recovery from shale matrix, it is essential to study its nanopore structure and confined fluid behavior.Small- and ultra-small-angle neutron scattering (SANS and USANS) have emerged as a powerful method for characterizing shale nanopore structure and confined fluid behavior. Owing to neutrons' high penetrating ability and high sensitivity to hydrogen (and its isotope, deuterium), SANS/USANS can probe inside shale samples to characterize nanopores from 1?nm to 10?μm in size and be readily combined with sample environmental cells to examine the fluid (hydrocarbon and water – frack fluid) behavior at relevant pressure-temperature (P-T) conditions. In this review article, an introduction is first given on the characteristics of shale matrix and the uniqueness of SANS/USANS compared with conventional methods. Then current studies on shale nanopore structure and confined fluid properties using SANS/USANS are summarized. Finally, an outlook and perspective on future research in this emerging area will be offered.Xu, L., Huang, S., Liu, Y., Wei, S., Chen, G., Gong, Z., Ouyang, G., 2020. Hollow carbon nanobubbles-coated solid-phase microextraction fibers for the sensitive detection of organic pollutants. Analytica Chimica Acta 1097, 85-93., a novel solid-phase microextraction (SPME)fiber based on hollow carbon nanobubbles was developed for the analysis of persistent organic pollutants. The hollow carbon nanobubbles (HCNBs), derived from the nanoscale zeoliticimidazolate framework (ZIF-8), not only possessed the ZIF-8-like microporous shell but also created an internal space for analytes storage. This architecture was beneficial to accelerating the mass transfer process and enhancing the enrichment capacity towards target analytes. As a result, the sensitivity of this HCNBs based SPME fiber toward analytes (e.g., BTEX, PAHs and PCBs) was 2–180 times higher compared with the commercial fibers (100?μm PDMS, 65?μm PDMS/DVB or 85?μm?PA). In addition, owing to the size-selectivity of the microporous shell, the HCNBs-based SPME fiber showed high extraction ability towards target analytes with low molecule weight. Furthermore, the lifespan of the homemade fiber was evaluated to be more than 100 times attributing to the hard and stable carbon framework. Under optimal working conditions, analytical performance of the fiber towards PCBs with varying chlorination degrees showed a wide linear range (0.05–1000?ng?L?1) and low LODs (0.0017–0.0042?ng?L?1). Finally, the established method was successfully applied to the determinations of PCBs in three environmental water samples with good recoveries (84.5–117.1%).Xu, L., Li, X., Wang, X., Song, A., Han, F., 2020. A feasible strategy based on isotopic fine structures to enhance the reliability of metabolite identification by Fourier transform ion cyclotron resonance mass spectrometry. Rapid Communications in Mass Spectrometry 34, e8560.: In the process of the identification of unknown metabolites, the most important thing is to determine their real chemical formulae according to the accurate masses which are determined by high‐resolution mass spectrometry. However, high mass accuracy alone is not enough to exclude false candidates. Use of isotopic fine structures (IFSs) derived from Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR MS) as a single further constraint could decisively determine the molecular formulae for unknown metabolites.Methods: Gastrodin, an active constituent from Gastrodia elata Bl., which can penetrate through the blood–brain barrier and rapidly decompose to p‐hydroxybenzyl alcohol in the brain, was selected as a model drug. The accurate masses, possible chemical formulae and IFSs of its metabolites in rat plasma were acquired using FT‐ICR MS. Results: Besides gastrodin, a total of eight metabolites including two phase I and six phase II metabolites were detected. Their chemical formulae were decisively determined by IFSs. Furthermore, their chemical structures were identified by comparing their fragment ions with those of gastrodin. Results indicated the metabolic pathways of gastrodin in rats including deglycosylation, oxidation, glucuronidation, sulfate conjugation and glycine conjugation.Conclusions: It is demonstrated that IFSs are effective in unambiguous determination of chemical formulae of metabolites. It could be used as a feasible strategy to enhance the reliability of metabolite identification in drug metabolism studies.Xu, P., Du, H., Peng, X., Tang, Y., Zhou, Y., Chen, X., Fei, J., Meng, Y., Yuan, L., 2020. Degradation of several polycyclic aromatic hydrocarbons by laccase in reverse micelle system. Science of The Total Environment 708, 134970. of polycyclic aromatic hydrocarbons (PAHs) in oily sludge has become the focus of attention. UV spectrophotometer analysis showed that four types of PAHs were found in sample, which including phenanthrene, anthracene, benzo(a)anthracene and benzo(b)fluoranthene. In order to degrade PAH effectively, the laccase reverse micelles system was proposed. The system protects laccase from being affected by organic phase. Reverse micelles were prepared by using isooctane to simulate oil. The optimum water content W0 was 10 by measuring the electrical conductivity of the system. Under this condition, the effects of pH, temperature and ionic strength on the degradation rate of PAHs were investigated. Also, compared with that of non-immobilized laccase, the ratio between the secondary structures of laccase under different conditions was studied. The results showed that the highest laccase activity was obtained at pH 4.2 and 30?°C with 60?mmol/L KCl. Meanwhile, the structure of α-helix accounts for the largest proportion, and the ratio of α-helix in the laccase secondary structure in the laccase-reverse micelle system was higher than that of the non-immobilized one under this condition. Finally, predicting the reactive site of the degradation of polycyclic aromatic hydrocarbons was simulated by ORCA (Version 4.2.0). The application in oily sludge was further conducted. This study provides an effective method and basis for the degradation of PAHs in oily sludge.Xu, S., Gou, Q., Hao, F., Zhang, B., Shu, Z., Lu, Y., Wang, Y., 2020. Shale pore structure characteristics of the high and low productivity wells, Jiaoshiba shale gas field, Sichuan Basin, China: Dominated by lithofacies or preservation condition? Marine and Petroleum Geology 114, 104211. the characteristics of lithofacies and tectonic movements are important factors in controlling the development, destruction, and preservation of pores in shale reservoirs. However, the main factors that control the structure of shale pores are complex and highly disputed, restricting the understanding of the mechanisms that lead to the accumulation of shale gas. In this study, mineral composition and geochemical analyses, high resolution field emission scanning electron microscopy (FE-SEM), and low-pressure gas adsorption (N2 and CO2) were conducted to evaluate the pore systems of different types shale in the Jiaoshiba area, Sichuan Basin. A total of three shale groups, including silica-rich high production shales, clay-rich low production shales, and silica-rich low production shales were identified on the basis of lithofacies and gas-bearing characteristics.The highest values of TOC, pore volume, and specific surface area are found in the silica-rich high production shales, with an average of 4.182%, 33.04 × 10?3 cm3/g, and 38.71 m2/g, respectively. The total pore volume and specific surface area in the clay-rich low production shales are 19.85% and 28.62% lower than that of silica-rich high production shales. This suggests that the types of lithofacies have a more prominent influence on the specific surface area of the shales, while the pore volume plays a smaller role. However, the pressure in silica-rich low production shales is often released due to strong tectonic deformation. The OM pores in the silica-rich low production shales therefore tend to be both compressed and closed, with low surface porosity and of round shape. The total pore volume and specific surface area of silica-rich low production shales are 34.63% and 22.0% lower than that of the silica-rich high production shales. This indicates that tectonic movement has a significant influence on the shale pore volume, while specific surface area has a smaller influence.Xue, P., Zhang, L., Liang, Q., Sun, X., Zhao, Q., Qi, P., 2019. Thermodynamic characteristics of CH4 adsorption by continental shale: A case study of the Upper Triassic Yanchang Shale in the Yanchang Gasfield, Ordos Basin. Natural Gas Industry 39, 64-73. Chinese. In order to improve the calculation method of the isosteric adsorption heat, clarify thermodynamic characteristics of CH4 adsorption by continental shale and reveal the adsorption mechanism, this paper selected shale samples from the seventh Member of Yanchang Formation of Upper Triassic in the Yanchang Gasfield of the Ordos Basin as the research object. The isothermal adsorption experiment was carried out on the CH4 adsorption by continental shale and the excess adsorption curves were plotted. Then, the characteristics of the isosteric adsorption heat of the shale with different types of adsorption capacity were illustrated by analyzing and comparing the difference between excess and absolute adsorption capacity. And the following research results were obtained. First, under the same temperature and pressure, absolute adsorption capacity is higher than the excess values. The difference between them is higher under low temperature and high pressure and it is in the relationship of exponential function with the equilibrium pressure. If excess adsorption capacity is used to evaluate the adsorptive property of shale reservoirs, the evaluation result will be underestimated. Second, for CH4 adsorption by Yanchang Formation shale, the absolute and excess isosteric adsorption heat values have a linear positive correlation with absolute and excess adsorption capacity respectively, and the intermolecular force of adsorbate has a dominant effect on isosteric adsorption heat values. Third, absolute isosteric adsorption heat value is less than the excess heat. The relative error is in the range of 18.18–49.79%, and it is higher in the stage with low adsorption capacity. If excess adsorption capacity is taken as the basic data to calculate initial isosteric adsorption heat values, the calculation result will overvalued, and consequently the evaluation on the intermolecular force of adsorbent and adsorbate is overestimated.Yakubova, S.G., Abilova, G.R., Tazeeva, E.G., Borisova, Y.Y., Milordov, D.V., Mironov, N.A., Yakubov, M.R., 2019. Distribution of vanadium and nickel in the case of two-step solvent fractionation of asphaltenes of heavy oils. Petroleum Chemistry 59, S30-S36. features of the distribution of vanadium and nickel in the products of two-step solvent fractionation of asphaltenes have been using the exampley of heavy crude oils from various fields of the Volga–Urals oil-and-gas basin (Russia). At the first step, during the treatment of a solution of asphaltenes in toluene with an excess of n-hexane, vanadium and nickel are predominantly concentrated in the insoluble fraction that is characterized by increased molecular weight, aromaticity, and degree of condensation with a decreased fraction of heteroatomic sulfur- and oxygen-containing structures. At the second step, during the treatment of the solution of asphaltene fractions in toluene with an excess of dimethylformamide, characteristic features of the distribution of vanadium and nickel in the obtained fractions have been revealed for heavy oils from different fields. As a result, differences in the concentration of metal complexes of vanadyl with asphaltenes have been determined for the heavy oils from Carboniferous and Permian productive sediments.Yamada, Y., Guillemette, R., Baudoux, A.-C., Patel, N., Azam, F., 2020. Viral attachment to biotic and abiotic surfaces in seawater. Applied and Environmental Microbiology 86, e01687-19.: Viruses influence microbial community structure and biogeochemical cycles in marine environments. Viral attachment to nonhost surfaces could influence host viral infection rates; however, the prevalence of such viral attachment is not investigated quantitatively. We used coastal seawater viral assemblages and, as models, marine vibriophage (SIO-2) and enterobacteriophages (T2 and T4) to investigate their attachment to probable nonhost marine bacteria. We also studied viral attachment to colloids and other abiotic surfaces in seawater. Centrifugation experiments with bacterium-virus mixtures showed substantial viral loss in the supernatant presumably due to the viral attachment to bacteria. This attachment (0.04 to 24 viruses μm?2 [bacterial surface area]) varied with bacterium-virus combinations. Surprisingly, filtering seawater on 0.2-μm Anodisc or polycarbonate filters retained ～12 to 84% of viruses presumably attached to ≥0.2-μm-sized particles and/or the filter surface. Enzymatic digestion followed by epifluorescence and atomic force microscopy suggested that 7 to 25% of the total viruses were attached via β-glycosidic linkages. Furthermore, a substantial proportion (7 to 48%) of viruses became attached to model abiotic surfaces (polycarbonate, polypropylene, and glass), and this has significance for laboratory protocols as well as studies of virus ecology in particle-rich marine environments. Substantial attachment of viruses to nonhost surfaces could influence virus-driven biogeochemical cycles and microbial community structure.Importance: Viruses play important roles in altering microbial community structure and biogeochemical cycles in marine environments. Viral attachment to nonhost surfaces can influence host viral infection rates; however, the prevalence of viral attachment to nonhost surfaces and the ratio of attached viruses to total viruses are little known. We used coastal seawater viral assemblages and used marine vibriophage (SIO-2) and enterobacteriophages (T2 and T4) as models to investigate their attachment to abiotic and biotic surfaces in seawater. Viral attachment was observed on several surfaces, such as nonhost bacteria, polymers, filters, cover glasses, and tube surfaces. This study cautions against commonly used protocols that require viral incubation and seawater fractionation. More importantly, these results could influence virus-driven biogeochemical cycles and microbial community structure in the ocean.Yamashita, Y., Yagi, Y., Ueno, H., Ooki, A., Hirawake, T., 2020. Characterization of the water masses in the shelf region of the Bering and Chukchi seas with fluorescent organic matter. Journal of Geophysical Research: Oceans 124, 7545-7556. water is an important nutrient source for sustaining biological production in the Chukchi Sea, western Arctic Ocean, which is one of the productive regions in the world. Therefore, to understand the impacts of future environmental changes on biological production in the sea, it is crucial to understand the origins, modification processes, and spatiotemporal variations of the water masses from the Bering Sea with changes in nutrient concentrations. To improve water mass analysis in the shelf regions of the Bering and Chukchi Seas, we observed levels of humic‐like fluorescent organic matter (FOMH) by using an in situ fluorometer directly connected to a temperature‐salinity sensor during a cruise in the early summer of 2013 and evaluated the potential of FOMH as a third parameter of water mass analysis. The levels of FOMH were different among specific water masses in the region, and FOMH seemed to behave semiconservatively in the shelf regions of the Bering and Chukchi Seas during the early summer of 2013. The distributional pattern of FOMH implies that FOMH estimated by the in situ fluorometer has the potential to (1) separate warm water into riverine‐affected Alaskan Coastal Water and historically photobleached summer Bering Basin Water; (2) distinguish the Anadyr Water, which has low FOMH levels and high nutrient concentrations, from the Bering Shelf Water; and (3) determine different formation/modification processes of dense shelf water that contains high nutrient concentrations.Yang, B., Steiner, M., Schiffbauer, J.D., Selly, T., Wu, X., Zhang, C., Liu, P., 2020. Ultrastructure of Ediacaran cloudinids suggests diverse taphonomic histories and affinities with non-biomineralized annelids. Scientific Reports 10, 535. have long been considered the earliest biomineralizing metazoans, but their affinities have remained contentious and undetermined. Based on well-preserved ultrastructures of two taxa, we here propose new interpretations regarding both their extent of original biomineralization and their phylogenetic affinity. One of these taxa is a new cloudinid from Mongolia, Zuunia chimidtsereni gen. et sp. nov., which exhibits key characteristics of submicrometric kerogenous lamellae, plastic tube-wall deformation, and tube-wall delamination. Multiple carbonaceous lamellae are also discovered in Cloudina from Namibia and Paraguay, which we interpret to have originated from chitinous or collagenous fabrics. We deduce that these cloudinids were predominantly originally organic (chitinous or collagenous), and postmortem decay and taphonomic mineralization resulted in the formation of aragonite and/or calcite. Further, based on our ultrastructural characterization and other morphological similarities, we suggest that the cloudinids should most parsimoniously be assigned to annelids with originally organic tubes.Yang, F., Zhou, X., Peng, Y., Song, B., Kou, X., 2020. Evolution of Neoproterozoic basins within the Yangtze Craton and its significance for oil and gas exploration in South China: An overview. Precambrian Research 337, 105563. on a comprehensive review of published results, the plate tectonic setting of the Neoproterozoic basins in the Yangtze Craton can be summarized as evolving from the Qingbaikou convergent continental margin to the Nanhua-Sinian divergent continental margin. Four phases of basin evolution are identified in the Neoproterozoic Yangtze Craton based on the prototype basin classification scheme: a) the early Qingbaikou period (ca. 1000–820?Ma), with back-arc spreading basins on the western and northern Yangtze margins and the interior, and a retro-arc foreland basin on the southeastern Yangtze margin; b) the late Qingbaikou period (ca. 820–720?Ma), with back-arc spreading basins on the western and northern Yangtze margins and extensional down-faulted basins on the southeastern Yangtze margin and the interior of the carton; c) the Nanhua period (ca. 720–635?Ma), with rift basins on the southeastern, western, and northern Yangtze margins and the interior; and d) the Sinian period (ca. 635–541?Ma), with intracratonic rift basins in the interior of Yangtze Craton and divergent marginal subsidence basins on the southeastern and northern Yangtze margins. The temporal sequence and spatial distribution of the major prototype basins associated with the four stages of basin evolution in the Yangtze Craton were further identified. By comparing the petroleum exploration practices in China and abroad, this paper concludes that the Nanhua rift basins on the southeastern and northern Yangtze margins, the Sinian divergent marginal subsidence basins on the southeastern and northern Yangtze margins and the intracratonic rift basins in the interior Yangtze Craton were most conducive to source rock formation and are target regions for future oil and gas exploration.Yang, H., Zhao, S., Liu, Y., Wu, W., Xia, Z., Wu, T., Luo, C., Fan, T., Yu, L., 2019. Main controlling factors of enrichment and high-yield of deep shale gas in the Luzhou Block, southern Sichuan Basin. Natural Gas Industry 39, 55-63. Chinese. The key to the scale development of deep shale gas lies in a better understanding of the main controlling factors for its enrichment and high-yield. In this regard, the high-quality shale of the Upper Ordovician Wufeng–Longmaxi Formations in the Luzhou Block, southern Sichuan Basin, was taken as the research object. Based on drilling, logging, seismic and analytical test data of a typical core well there, an in-depth study was conducted on the tectonic, sedimentary, and reservoir characteristics and compressibility of shale in this study area. On this basis, combined with production performance, the main controlling factors of a high-yield shale gas well were discussed. The following findings were achieved.（1） There are two sets of type-I reservoirs with high gas saturation, high total gas content and high brittle mineral content vertically. One is S1 l111–3 sub-layers with a thickness of 10–20 m, the other is S1 l114 sub-layer with a thickness of 3–10 m.（2） The thicker the type-I reservoir, the longer the targeted horizontal sections, and the higher initial production rate of a horizontal shale gas well. Under the same scenario, the trial test production rate of a shale gas well in the Luzhou Block is 10–25% higher than that in the Changning and Weiyuan blocks.（3） The deep shelf sedimentary center controls the distribution of high-quality shale in the Luzhou Block, and under the setting of low deep structure and abnormally high pressure, those well-developed high-angle natural fractures are good for the accumulation of free gas, and due to a high brittle material content there, the complex fracture networks are easily formed by fracturing, as a result, a high yield will be easily achieved for a shale gas well in this study area. In conclusion, high-yield and enrichment of shale gas reservoirs should be under such favorable conditions as being located in the deep-water shelf sedimentary center and with well-developed high-angle natural fractures under the setting of low steep structure and abnormally high pressure.Yang, S., 2020. An analytical model for fluid imbibition in organic nanopores. Transport in Porous Media 131, 595-615. the fluid imbibition flow in natural system composed of nanopores is challenging due to the strong fluid/rock molecular scale interaction and the invalidation of the macroscopic thermodynamics treatment. We develop an analytical model for Lennard-Jones fluid imbibition into an organic nanopore considering the phase transition and fluid/rock intermolecular interactions. In addition, we apply the proposed model on octane molecules imbibition into 1–10 nm slit-shape graphite nanopores under the standard and shale reservoir condition. Predicted velocity and density profiles of 2 nm model at the standard condition show that octane molecules first imbibe as vapor phase at around 200–300 m/s and form adsorbed layers near the pore wall. Velocity and density profiles are compared with the molecular dynamic simulation results. Calculated mean velocities of the analytical model and simulation are around 103–104 of those predicted by classical models, which are similar with previous experimental results. Reservoir condition results show octane can fast flow only when the driving pressure is greater than 0.12 MPa when the initial reservoir pressure is 5.72 MPa. Particularly, the impact of the fluid phase transition on the imbibition rate is significant in organic nanopores.Yang, W., He, S., Iglauer, S., Guo, X., Zhai, G., Zhou, Z., Dong, T., Tao, Z., Wei, S., 2020. Porosity characteristics of different lithofacies in marine shale: A case study of Neoproterozoic Sinian Doushantuo formation in Yichang area, China. Journal of Petroleum Science and Engineering 187, 106856. study evaluates the pore network systems in the Neoproterozoic Sinian Doushantuo (Z1d) shale from the Yichang area in the Middle Yangtze region. All samples were classified based on their lithologies and examined by geochemical and petrographic analysis, assisted with carbon dioxide/nitrogen (CO2/N2) adsorption, mercury injection capillary pressure (MICP) and focused ion beam-scanning electron microscopy (FIB-SEM) to fully characterize the nanoscale porosity of the different shale lithofacies. The calcareous shale lithofacies group (I-C), mixed shale lithofacies group (II-M) and siliceous shale lithofacies group (III-S) were identified via ternary mineralogy diagrams. Clearly, different lithofacies had different porosities, pore volume, surface area and pore-size distribution (ranging from 0.3?nm to 36?μm). The mixed shale lithofacies group (II-M) had the highest total pore volumes, followed by the calcareous shale lithofacies group (I-C) and the siliceous shale lithofacies group (III-S). Peak values (2–20?nm, 20–50?nm, 50–60?nm and 90–200?nm) obtained from N2 adsorption were identified as organic matter (OM) pores, dissolution intraparticle (intraP) pores and intercrystalline pores (using SEM images analysis). Porosity shows a non-monotonic trend with TOC content and a maximum at 4.5–5.5?wt% TOC, similar relationships between TOC and mesopore/macropore volumes, due to pore collapse and compaction. The FIB-SEM images revealed solid bitumen and two types of kerogen in the examined shale samples; these different organic matter types had clearly distinct pore characteristics. While the smaller OM particles mobilized and converted into solid bitumen in which OM pores were larger and more abundant, the large-scale OM particles were most likely non-porous inert maceral and sponge-like porous amorphous kerogen. Overall TOC content and organic types are the key controlling factors to the nanoscale porosity development in the Doushantuo Shale, and the Sinian Doushantuo shale (in the Yichang area) has great potential for shale gas exploration and exploitation in South China.Yin, A., Brandl, G., Kr?ner, A., 2019. Plate-tectonic processes at ca. 2.0 Ga: Evidence from >600 km of plate convergence. Geology 48, 103-107. addressed when plate-tectonic processes first started on Earth by examining the ca. 2.0 Ga Limpopo orogenic belt in southern Africa. We show through palinspastic reconstruction that the Limpopo orogen originated from >600 km of west-directed thrusting, and the thrust sheet was subsequently folded by north-south compression. The common 2.7–2.6 Ga felsic plutons in the Limpopo thrust sheet and the absence of an arc immediately predating the 2.0 Ga Limpopo thrusting require the Limpopo belt to be an intracontinental structure. The similar duration (～40 m.y.), slip magnitude (>600 km), slip rate (>15 mm/yr), tectonic setting (intracontinental), and widespread anatexis to those of the Himalayan orogen lead us to propose the Limpopo belt to have developed by continent-continent collision. Specifically, the combined Zimbabwe-Kaapvaal craton (ZKC, named in this study) in the west (present coordinates) was subducting eastward below an outboard craton (OC), which carried an arc equivalent to the Gangdese batholith in southern Tibet prior to the India-Asia collision. The ZKC-OC collision at ca. 2.0 Ga triggered a westward jump in the plate convergence boundary, from the initial suture zone to the Limpopo thrust within the ZKC. Subsequent thrusting accommodated >600 km of plate convergence, possibly driven by ridge push from the west side of the ZKC. As intracontinental plate convergence is a key modern plate-tectonic process, the development of the Limpopo belt implies that the operation of plate tectonics, at least at a local scale, was ongoing by ca. 2.0 Ga on Earth.Yoneda, J., Kida, M., Konno, Y., Jin, Y., Morita, S., Tenma, N., 2019. In situ mechanical properties of shallow gas hydrate deposits in the deep seabed. Geophysical Research Letters 46, 14459-14468. gas hydrates (or methane hydrates) could become a major energy source but could also exacerbate global warming, because as the climate warms, hydrate deposits deep under the oceans or in permafrost may release methane into the atmosphere. There are many shallow deposits of gas hydrates in fine-grained muddy sediments on the seafloor. However, the mechanical properties of these sediments have not yet been investigated because of the engineering challenges in coring and testing at in situ temperatures and pressures. Here we present the first uniaxial and triaxial strength and stiffness measurements of pure massive natural gas hydrates and muddy sediments containing hydrate nodules obtained by pressure coring. As a result, we were able to observe the hydrate undergoing a catastrophic brittle failure. Its strength and deformation moduli were 3 and 300 MPa, respectively. Muddy sediments containing hydrate nodules had the same strength as that of hydrate-free sediments.Yoo, C.G., Meng, X., Pu, Y., Ragauskas, A.J., 2020. The critical role of lignin in lignocellulosic biomass conversion and recent pretreatment strategies: A comprehensive review. Bioresource Technology 301, 122784. and rigidity of lignocellulose causing resistance to its deconstruction have provided technical and economic challenges in the current biomass conversion processes. Lignin has been considered as a crucial recalcitrance component in biomass utilization. An in-depth understanding of lignin properties and their influences on biomass conversion can provide clues to improve biomass utilization. Also, utilization of lignin can significantly increase the economic viability of biorefinery. Recent lignin-targeting pretreatments have aimed not only to overcome recalcitrance for biomass conversion but also to selectively fractionate lignin for lignin valorization. Numerous studies have been conducted in biomass characteristics and conversion technologies, and the role of lignin is critical for lignin valorization and biomass pretreatment development. This review provides a comprehensive review of lignin-related biomass characteristics, the impact of lignin on the biological conversion of biomass, and recent lignin-targeting pretreatment strategies. The desired lignin properties in biorefinery and future pretreatment directions are also discussed.Yu, C., Zhong, R., Bai, R., Wang, Y., Ling, Y., 2020. A method to predict the homogenization temperatures of easily decrepitated fluid inclusions. Ore Geology Reviews 117, 103311. homogenization temperature (Th) is a basic work in fluid inclusion studies. However, the Th of some fluid inclusion is hard to obtain using the traditional microthermometric method, in particular those that is easy to decrepitate upon heating. Such inclusions are common when the host minerals have well-developed cleavages (e.g., calcite and fluorite) and the fluids are enriched in volatile components such as CO2 or CH4. In theory, upon heating of H2O-NaCl and H2O-CO2-NaCl inclusions that tends to homogenize to the liquid phase, their bubble volumes (Vg) will decrease with increasing temperatures (T) following cubic and quartic polynomial Vg-T functions, respectively. A method that can predict inclusion Th without heating it to homogenization is proposed in this study. The core idea is to retrieve the Vg-T function of a given inclusion based on a series of (Vg, T) data points that were measured before total homo genization (or decrepitation of the inclusion), and then calculate the Th based on the function (the temperature at which Vg equals to zero). To test the performance of this method, a total of 14 synthetic and natural fluid inclusions were heated to homogenization (at Th, real) and their changes in Vg were recorded with increasing temperature. It is assumed that the inclusions get decrepitated before homogenization, and their homogenization temperatures were predicted (Th, predicted) using the method proposed by this study. If the inclusions were “decrepitated” at temperatures 40 °C below the Th, real, the differences between the predicted and real homogenization are mostly smaller than 3 °C. This approach provides a quantitative estimation of the Th for inclusions that are easy to decrepitation, and is much more accurate than directly using the temperature of decrepitation as an approximation of Th. This method was programed in two Microsoft EXCEL worksheets that are available in Supplementary Materials for Th calculations of H2O-NaCl and H2O-CO2-NaCl inclusions, respectively.Yu, H., Fan, J., Xia, J., Liu, H., Wu, H., 2020. Multiscale gas transport behavior in heterogeneous shale matrix consisting of organic and inorganic nanopores. Journal of Natural Gas Science and Engineering 75, 103139. complicated nanoporous structure and significant heterogeneity of shale matrix make it challenging to fully understand the gas transport behavior in shale. Towards this end, herein a multiscale approach was presented via coupling molecular dynamics (MD) simulations, analytical model and pore network model (PNM). Using MD simulations, we showed that gas transport in organic nanopores manifests a typical slippage feature whereas gas slippage breaks down in inorganic nanopores, which should be attributed to “rough” potential energy surface (PES) of inorganic walls. Based on the results of MD simulations, a unified gas transport model was derived to describe gas flow behaviors in organic and inorganic pores by integrating continuum flow theory and gas-surface dynamics theory. In particular, gas transport process in heterogeneous shale matrix was performed with the help of pore network model and the influence of multiple factors on the gas permeability of shale matrix were analysed and discussed.Yu, K., Duan, Y., Gan, Y., Zhang, Y., Zhao, K., 2020. Anthropogenic influences on dissolved organic matter transport in high arsenic groundwater: Insights from stable carbon isotope analysis and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. Science of The Total Environment 708, 135162. East and Southeast Asia, the health of over 100 million people is threatened by the consumption of groundwater containing high concentrations of arsenic (> 10 μg L?1), which is released from sediments through reductive dissolution of arsenic-bearing iron/manganese oxides. Dissolved organic matter (DOM) is known to play a crucial role in the process of arsenic mobilization in shallow aquifers, and its availability and reactivity are key factors controlling the variation of arsenic concentrations in groundwater. However, it is unclear how human activities influence the transport of DOM and how the transportation affects the DOM molecular properties in high arsenic groundwater. This study provides insights on the sources and molecular compositions of DOM in groundwater from the Jianghan Plain, central China, a newly discovered area with seasonal fluctuations in arsenic concentrations in shallow groundwater. Monitoring of water levels and stable carbon isotope compositions in groundwater from different depths and canal water over a year indicated that terrestrial DOM was the dominant source, accounting for 54.2%–85.5% of groundwater DOM. Electrospray ionization combined with ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry revealed that canal water infiltration transferred aliphatic, tannin-like and leached aromatic DOM from sediments into groundwater. Therefore, groundwater recharge through irrigation using canal water not only inputs terrestrial DOM, but also accelerates the release of sedimentary DOM. Furthermore, carboxylic-rich alicyclic molecule (CRAM)-like DOM that is derived from biomolecules has the highest proportion (60.1%–65.5%) among the identified DOM structures. And, it might be reused in biochemical processes during arsenic mobilization, suggesting a third source of groundwater DOM in addition to canal water and sediments. The findings in this study advance the understanding on transport processes and molecular properties of DOM in high arsenic groundwater under extensive anthropogenic influences.Yu, X., Millet, D.B., Wells, K.C., Griffis, T.J., Chen, X., Baker, J.M., Conley, S.A., Smith, M.L., Gvakharia, A., Kort, E.A., Plant, G., Wood, J.D., 2020. Top-down constraints on methane point source emissions from animal agriculture and waste based on new airborne measurements in the U.S. Upper Midwest. Journal of Geophysical Research: Biogeosciences 125, e2019JG005429.: Agriculture and waste are thought to account for half or more of the U.S. anthropogenic methane source. However, current bottom‐up inventories contain inherent uncertainties from extrapolating limited in situ measurements to larger scales. Here, we employ new airborne methane measurements over the U.S. Corn Belt and Upper Midwest, among the most intensive agricultural regions in the world, to quantify emissions from an array of key agriculture and waste point sources. Nine of the largest concentrated animal feeding operations in the region and two sugar processing plants were measured, with multiple revisits during summer (August 2017), winter (January 2018), and spring (May–June 2018). We compare the top‐down fluxes with state‐of‐science bottom‐up estimates informed by U.S. Environmental Protection Agency methodology and site‐level animal population and management practices. Top‐down point source emissions are consistent with bottom‐up estimates for beef concentrated animal feeding operations but moderately lower for dairies (by 37% on average) and significantly lower for sugar plants (by 80% on average). Swine facility results are more variable. The assumed bottom‐up seasonality for manure methane emissions is not apparent in the aircraft measurements, which may be due to on‐site management factors that are difficult to capture accurately in national‐scale inventories. If not properly accounted for, such seasonal disparities could lead to source misattribution in top‐down assessments of methane fluxes.Plain Language Summary: Key agricultural methane sources are quantified using new airborne measurements in the U.S. Corn Belt and Upper Midwest. Measurements spanned multiple seasons and targeted nine of the largest concentrated animal feeding operations in the region along with two sugar processing plants. Compared with bottom‐up estimates informed by U.S. Environmental Protection Agency methodology and site‐level animal and management data, top‐down fluxes agree well with bottom‐up estimates for beef but are lower for dairies and sugar plants and suggest a possible mismatch in the timing of emissions.Yu, Y., Li, G., Wu, D., Liu, J., Chen, J., Hu, N., Wang, H., Wang, P., Wu, Y., 2020. Thiol radical-based chemical isotope labelling for sterols quantitation through high performance liquid chromatography-tandem mass spectrometry analysis. Analytica Chimica Acta 1097, 110-119. by the high specificity and reactivity of thiol radical toward allyl, here, we first established a rapid thiol radical-based chemical isotope-labelling (CIL) strategy coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis for the quantitative profiling of sterols. In this strategy, N-(4-(carbazole-9-yl)-phenyl)-N-maleimide labelled derivative of ethylenedithiol (NCPM-d0-SH) and its deuterated analogue NCPM-d2-SH were employed as a novel pair of CIL reagents to efficiently label sterols. Under lighting condition, the thiol radical obtained from NCPM-d0/d2-SH attacks one allyl hydrogen in the B-ring of sterols to produce a reactive radical intermediate which can quickly react with another thiol radical to form the last labelled derivatives. This labelling reaction can rapidly complete only within 1.5 min. Absorbingly, the NCPM-d0-SH and NCPM-d2-SH labelled derivatives of sterols can produce two specific product ions (PIs) containing different isotope tags at m/z of 431.6 and 433.6 via collision induced dissociation, which were employed to develop the multiple reaction monitoring (MRM) mode-based analysis. According to the specific mass differences with a fixed value, the peak pairs with similar retention times can be easily extracted from the two PIs spectrums and designated as the candidates for the identification of sterols. NCPM-d0-SH and NCPM-d2-SH labelled derivatives of sterols can be readily distinguished from their several ion chromatograms. Thus, sterols from two samples labelled by different isotope tags were ionized at the same conditions and measured respectively, providing excellent identification and precise quantitation by compensating the matrix effect and instrument fluctuation during MS-based analysis. The detection sensitivities of thiol-containing drugs improved by 53.5–560.3-fold due to NCPM-labelling. The limits of detection (LODs) and the limits of quantitation (LOQs) were in the range of 0.15–0.40 μg kg?1 and 0.50–1.30 μg kg?1, respectively. Using the developed method, we quantitatively profiled five sterols in vegetable oils with good applicability. As promising, the proposed thiol radical-based CIL strategy is a potential platform for the quantitation of sterols.Yu, Y., Yang, J., Zheng, L.-Y., Sheng, Q., Li, C.-Y., Wang, M., Zhang, X.-Y., McMinn, A., Zhang, Y.-Z., Song, X.-Y., Chen, X.-L., 2020. Diversity of D-amino acid utilizing bacteria from Kongsfjorden, Arctic and the metabolic pathways for seven D-amino acids. Frontiers in Microbiology 10, 2983. doi: 10.3389/fmicb.2019. 02983. acids (DAAs) are an important component of the refractory dissolved organic matter pool in the ocean. Microbes play a vital role in promoting the recycling of DAAs in the ocean. However, the diversity of marine DAA-utilizing bacteria and how they metabolize DAAs are seldom studied. Here, by enrichment culture with DAAs as the sole nitrogen source, bacteria of 12 families from three phyla were recovered from surface seawater and sediment from Kongsfjorden, Arctic, and seven DAA-utilizing bacterial strains were isolated. These strains have different DAA-utilizing abilities. Of the seven DAAs used, Halomonas titanicae SM1922 and Pseudoalteromonas neustonica SM1927 were able to utilize seven and five of them, respectively, while the other strains were able to utilize only one or two. Based on genomic, transcriptional and biochemical analyses, the key genes involved in DAA metabolism in each strain were identified and the metabolic pathways for the seven DAAs in these marine bacteria were identified. Conversion of DAAs into α-keto acids is generally the main pathway in marine DAA-utilizing bacteria, which is performed by several key enzymes, including DAA oxidoreductases/dehydrogenases, D-serine ammonia-lyases, D-serine ammonia-lyase DSD1s and DAA transaminases. In addition, conversion of DAAs into LAAs is another pathway, which is performed by amino acid racemases. Among the identified key enzymes, D-serine ammonia-lyase DSD1 and Asp racemase are first found to be employed by bacteria for DAA utilization. These results shed light on marine DAA-utilizing bacteria and the involved DAA metabolism pathways, offering a better understanding of the DAA recycling in the ocean.Zander, T., Haeckel, M., Klaucke, I., Bialas, J., Klaeschen, D., Papenberg, C., Pape, T., Berndt, C., Bohrmann, G., 2020. New insights into geology and geochemistry of the Kerch seep area in the Black Sea. Marine and Petroleum Geology 113, 104162. 3D seismic data in combination with deep-towed sidescan sonar data and porewater analysis give insights into the seafloor expression and the plumbing system of the actively gas emitting Kerch seep area, which is located in the northeastern Black Sea in around 900?m water depth, i.e. well within the gas hydrate stability zone (GHSZ). Our analysis shows that the Kerch seep consists of three closely spaced but individual seeps above a paleo-channel-levee system of the Don Kuban deep-sea fan. We show that mounded seep morphology results from sediment up-doming due to gas overpressure. Each of the seeps hosts its own gas pocket underneath the domes which are fed with methane of predominantly microbial origin along narrow pipes through the GHSZ. Methane transport occurs dominantly in the form of gas bubbles decoupled from fluid advection. Elevated sediment temperatures of up to 0.3?°C above background values are most likely the result of gas hydrate formation within the uppermost 10?m of the sediment column. Compared to other seeps occurring within the GHSZ in the Black Sea overall only scarce gas indications are present in geoacoustic and geophysical data. Transport-reaction modeling suggests that the Kerch seep is a young seep far from steady state and probably not more than 500 years old.Zayulina, K.S., Kochetkova, T.V., Piunova, U.E., Ziganshin, R.H., Podosokorskaya, O.A., Kublanov, I.V., 2020. Novel hyperthermophilic crenarchaeon Thermofilum adornatum sp. nov. uses GH1, GH3, and two novel glycosidases for cellulose hydrolysis. Frontiers in Microbiology 10, 2972. doi: 10.3389/fmicb.2019. 02972. novel hyperthermophilic, anaerobic filamentous archaeon, Thermofilum adornatum strain 1910bT, is capable of growing with cellulose as its sole carbon and energy source. This strain was isolated from a terrestrial hot spring in Kamchatka, Russia. The isolate 1910bT grew optimally at a temperature of 80°C and a pH of 5.5–6.0, producing cell-bound inducible cellulases. During genome analysis, genes, encoding various glycosidases (GHs) involved in oligo- and polysaccharide hydrolysis and genes for the fermentation of sugars were identified. No homologs of currently known cellulase families were found among the GHs encoded by the 1910bT genome, suggesting that novel proteins are involved. To figure this out, a proteomic analysis of cells grown on cellulose or pyruvate (as a control) was performed. Both in-depth genomic and proteomic analyses revealed four proteins (Cel25, Cel30, Cel40, and Cel45) that were the most likely to be involved in the cellulose hydrolysis in this archaeon. Two of these proteins (Cel30 and Cel45) were hypothetical according to genome analysis, while the other two (Cel25 and Cel40) have GH3 and GH1 domains, respectively. The respective genes were heterologously expressed in Escherichia coli BL21 (DE3), and enzymatic activities of recombinant proteins were measured with carboxymethyl cellulose (CMC), Avicel and cellobiose as substrates. It was revealed that the Cel30 and Cel25 proteins were likely exoglucanases with side beta-glucosidase and endoglucanase activities, that Cel40 was a multifunctional glucanase capable of hydrolyzing beta-1,4-glucosides of various lengths, and that Cel45 was an endoglucanase with side exoglucanase activity. Taking into account that the cellulolytic activity of T. adornatum 1910bT surface protein fractions was inducible, that recombinant Cel25 and Cel30 were much less active than Cel40 and Cel45, and that their gene expressions were (almost) non-induced by CMC, we suggest that Cel40 and Cel45 play a major role in the degradation of cellulose, while Cel25 and Cel30 act only as accessory enzymes.Zhan, S., Wu, J., Wang, J., Jing, M., 2020. Distribution characteristics, sources identification and risk assessment of n-alkanes and heavy metals in surface sediments, Tajikistan, Central Asia. Science of The Total Environment 709, 136278. Asia is the global hotspot resulting from either a scarcity of natural resources or environmental degradation. Tajikistan, however, is called the “central Asian water tower”, is rich in water and minerals and plays a very important role in the ecology of Central Asia. Given the soil contamination issues in Tajikistan, the spatial distributions and sources of n-alkanes and heavy metals in surface sediments of Tajikistan were investigated. The evaluation of n-alkane and elemental indices helped to elucidate the origins of complex pollutants. The n-alkane indices were allowed to identify biogenic and petrogenic sources, and statistical methods were used to identify natural and anthropogenic sources of heavy metals. Enrichment factors were used to assess the contamination statuses of heavy metals. The results indicated that n-alkanes in the cluster I (sample 23) and II (samples 1, 5, 12, 14, 18, 22, 29, and 30) samples were affected by crude oil or incomplete fossil fuel combustion. Biomarker indices indicated strong contributions of petroleum sources to the n-alkanes in samples 14, 18, 23, and 29, but that n-alkanes in the other samples were mainly derived from higher plant waxes. Statistical analyses showed that cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), and zinc (Zn) were originated from industrial activities. Phosphorus (P) was closely related to local agricultural activities. Manganese (Mn) was derived from mining activities and industrial wastewater. The enrichment factors indicated that sediment was zero to minor contamination with Cr, Cu, Ni, and Pb, but moderate contamination with Cd and significant contamination with Zn. Interestingly, the samples contaminated with Cd included the cluster I and II samples, meaning the source of Cd contamination had agreed with the results of n-alkanes. The combined evaluation of n-alkanes and heavy metals suggested that their pollutant sources were crude oil contamination.Zhang, D., Xia, H., Cheng, T., Chen, F., 2020. New portraits of the Denisovans. Science Bulletin 65, 1-3., well known for their high-coverage genetic sequences, are considered to be a new human species genetically distinct from Neanderthals and modern humans [1]. As a close sister group of Neanderthals, Denisovans not only interbred with Neanderthals [2], but they also contributed genetically to extant humans, including modern populations in parts of Oceania and Asia, aboriginal Americans and high-altitude modern Tibetans [3], [4], [5]. This implies that Denisovans probably were once widespread in eastern Eurasia and Oceania, and that they also interbred with modern humans. Therefore, Denisovans probably have played an important role in human evolution in East Asia. However, due to the limited and fragmentary fossil record of Denisovans (Denisova 2, Denisova 3, Denisova 4, Denisova 8) (Fig. 1c), which is found only at Denisova Cave (Altai, Russia; 700?m a.s.l., meters above sea level; Fig. 1a) and obscure chronological issues regarding both human fossils and cave sediments, we know very little about this extinct human species, except for its high resolution genetic information.Two papers published in the January issue of Nature by Jacobs et al. [6] and Douka et al. [8] both aim to establish a reliable chronology for human occupation in Denisova Cave. Based on stratigraphic and site formation analysis and using optical dating of 103 cave sediment samples, Jacobs et al. [6] established a long chronology for the Pleistocene sedimentary sequence and archaeological remains in Denisova Cave, and they also reconstructed the paleoenvironment in the vicinity of the site, since 350?ka (thousand years ago). Combining this chronology with human fossils, archaeological and sedimentary DNA (deoxyribonucleic acid) evidence, they also estimated the timing of the occupation of Denisova Cave by Denisovans and Neanderthals. In addition, Douka et al. [8] built Bayesian models, based on diverse available information including cave sediment stratigraphy, the relative genetic dates of human remains, radiocarbon dates on charcoal, human fossils and animal bone artifacts, and one uranium-series date on human fossils, to estimate the ages of human fossils and the onset of the Upper Paleolithic at Denisova Cave. These two studies together provide reliable age controls for various human activities in Denisova Cave and have laid the foundation for further interpreting the relationships between Denisovans and Neanderthals, or even modern humans, at the site. According to these two studies, the oldest Denisovan fossils may have been as early as 195?ka (Denisova 2) [8], while archaeological remains and sedimentary DNA extracts indicate that the cave may have been occupied by Denisovans since around 300?ka (or, conservatively, around 200?ka) until 50?ka [6], overlapping with occupations of Neanderthals from 193 to 97?ka [8]. Therefore, Denisovans, as well as Neanderthals, in Denisova Cave, were coexisting with various other neighboring unknown species of middle Pleistocene archaic Homo sapiens (around 300–100?ka) [9] in East Asia. The question therefore arises as to the nature of their long coexistence for nearly 200?ka (thousand years). However, without sufficient knowledge of the physical morphological characteristics of Denisovans and genetic data of archaic Homo sapiens in East Asia, this question is difficult to address.A study published in Nature in May of 2019 by us and our co-authors, reported the discovery of the right-half of a hominin mandible (Fig. 1c) found in Baishiya Karst Cave (3200?m a.s.l.; Fig. 1b) (in Xiahe County, Gansu Province) in the northeastern Tibetan Plateau (Fig. 1a). It is identified by palaeoproteomic analysis as Denisovan, or from a Denisovan-related population, and dated to at least 160?ka by the U-series method [7]. As the evidence of the earliest hominin presence on the Tibetan Plateau, the Xiahe mandible shows that Denisovans have occupied the Tibetan Plateau since at least 160?ka, during the penultimate glacial period, 120 ka before the regional arrival of Modern Humans as indicated by the blade industry found at the Nwya Devu site (approximately 40?ka) [10]. We assume that the Xiahe Denisovans may have accumulated adaptive alleles as an adaptation to the extremely cold and hypoxic environments of the Tibetan Plateau, such as EPAS1 (Endothelial PAS domain-containing protein 1) found in both modern high-altitude Himalayans and the Siberian Denisovan genome [3]. More importantly, as the largest Denisovan fossil ever found (Fig. 1c) and the first Denisovan fossil discovered outside Denisova Cave, the Xiahe mandible confirms the hypothesis that Denisovans probably were once widely distributed in East Asia, and it also provides a valuable basis for physical anthropological comparisons between Denisovans and the current known archaic Homo sapiens found in East Asia. Morphological similarities between the Xiahe mandible and archaic Homo sapiens specimens in China, such as Penghu 1 and Xujiayao (Fig. 1a) [7], reveal that at least some of the Denisovan anatomical features occurred in known archaic Homo sapiens specimens in China, implying that some of them may have been Denisovans. Furthermore, the Xiahe mandible, as Denisovan with a 3-rooted lower molar (a specific characteristic commonly occurring in modern Asian populations (more than 40%) and in some Asian human fossils), implies substantial genetic contributions to modern Asian populations by Denisovans [11], consistent with previous genetic studies which traced different degrees of gene flows from Denisovans to modern Asian populations [3], [4], [5]. Therefore, the Xiahe mandible also provides important clues for addressing questions about the origins of Modern Humans in East Asia.In all, these three studies reveal several important details about the enigmatic Denisovans: that Denisovans could have been present in Asia since at least 160?ka or even 200? or 300?ka, during the Middle Pleistocene, co-existing with Neanderthals in western Eurasia and with unknown species of archaic Homo sapiens in eastern Eurasia, and that they persisted in parts of Asia until about 50?ka, contemporary with Modern Humans. There has been a large extension of the spatial distribution of the Denisovans in Asia – from Altai to the Tibetan Plateau – as a result of the discovery of the Xiahe Mandible. More excitingly, the faces of Denisovans are finally possible to be physically reconstructed (Fig. 1 d), aided by the Xiahe Mandible, ten years after the identification of this new human species. A study does paint a possible portrait of a female Denisovan based on skeletal traits derived from ancient DNA [12].However, many questions about the Denisovans still remain or are emerging. Because of the complexity of cave sediments and the limits of each dating method applied, there are several uncertainties regarding the chronological framework of Denisova Cave as established by Jacobs et al. [6] and Douka et al. [8], especially for human remains beyond the limit of the radiocarbon dating method. Moreover, due to the long coexistence of different human groups and the fact that human remains are not present within each layer at Denisova Cave, it is very difficult to determine who produced the near 300-thousand year record of archaeological remains in the cave. Although Jacobs et al. [6] assert that the earliest human occupation in Denisova Cave may have been Denisovans, and Douka et al. [8] claim that the Denisovans may have produced the tooth pendants and bone points in Denisova Cave, hard evidence is needed to confirm these hypotheses. Moreover, for the Xiahe mandible, a direct stratigraphic and archaeological context is still lacking [7], while the current U-series age of the carbonate matrix outside the mandible only provides a minimum age for the fossil. The lack of success in extracting ancient DNA from the Xiahe mandible also makes it difficult to evaluate the relationship among Xiahe Denisovans, Siberian Denisovans, and even modern Tibetans. In addition, the available physical morphological and genetic data are still insufficient to clearly interpret the complex relationships between Denisovans and other archaic Homo sapiens in East Asia.Further excavations and studies in Baishiya Karst Cave, where the Xiahe mandible was discovered, are likely to provide further information about the Xiahe Denisovans. In addition, more Denisovan fossils may be discovered or identified in East Asia in the future, especially in China, given the availability of new technologies including ancient DNA and palaeoproteomic analysis, as well as via physical anthropological morphological comparisons with the Xiahe mandible. These studies will not only help to provide a more detailed portrait of the Denisovans, but they will also contribute substantially to our understanding of human evolution, especially of the origins of Modern Humans in East Asia.References[1] M. Meyer, M. Kircher, M. Gansauge, et al. A high-coverage genome sequence from an archaic Denisovan individual. Science, 338 (2012), pp. 222-226[2] V. Slon, F. Mafessoni, B. Vernot, et al. The genome of the offspring of a Neanderthal mother and a Denisovan father. Nature, 560 (2018), pp. 417-418[3] E. Huerta-Sánchez, X. Jin, B.Z. Asan, et al. Altitude adaptation in Tibetans caused by introgression of Denisovan-like DNA. Nature, 512 (2014), pp. 194-197[4] S.R. Browning, B.L. Browning, Y. Zhou, et al. Analysis of human sequence data reveals two pulses of archaic Denisovan admixture. Cell, 173 (2018), pp. 53-61[5] G.S. Jacobs, G. Hudjashov, L. Saag, et al. Multiple deeply divergent Denisovan ancestries in Papuans. Cell, 177 (2019), pp. 1010-1012[6] Z. Jacobs, B. Li, M.V. Shunkov, et al. Timing of archaic hominin occupation of Denisova Cave in southern Siberia. Nature, 565 (2019), pp. 594-599[7] F.H. Chen, F. Welker, C.C. Shen, et al. A late Middle Pleistocene Denisovan mandible from the Tibetan Plateau. Nature, 569 (2019), pp. 409-412[8] K. Douka, V. Slon, Z. Jacobs, et al. Age estimates for hominin fossils and the onset of the Upper Palaeolithic at Denisova Cave. Nature, 565 (2019), pp. 640-644[9] XJ Wu. Recent research progress and popular issues on Chinese human evolution. Chin Sci Bull, 63 (2018), pp. 2148-2155 (in Chinese)[10] D.J. Zhang, H. Xia, F.H. Chen. Early human occupation of the Tibetan Plateau. Sci Bull, 63 (2018), pp. 1598-1600[11] E.B. Shara, H. Jean-Jacques, C.A. Susan. Rare dental trait provides morphological evidence of archaic introgression in Asian fossil record. Proc Natl Acad Sci USA, 116 (2019), pp. 14806-14807[12] D. Gokhman, N. Mishol, M. de Manuel, et al. Reconstructing Denisovan anatomy using DNA methylation maps. Cell, 179 (2019), pp. 180-192Zhang, F., Dahl, T.W., Lenton, T.M., Luo, G., Shen, S.-z., Algeo, T.J., Planavsky, N., Liu, J., Cui, Y., Qie, W., Romaniello, S.J., Anbar, A.D., 2020. Extensive marine anoxia associated with the Late Devonian Hangenberg Crisis. Earth and Planetary Science Letters 533, 115976. global Hangenberg Crisis near the Devonian-Carboniferous boundary (DCB) represents one of the major Phanerozoic mass extinction events, which shaped the roots of modern vertebrate biodiversity. Marine anoxia has been cited as the proximate kill mechanism for this event. However, the detailed timing, duration, and extent of global marine redox chemistry changes across this critical interval remain controversial because most of the studies to date only constrain changes in local or regional redox chemistry. Thus, opinions on the significance of anoxia as a kill mechanism are variable—from anoxia being a primary driver to being relatively unimportant. In this study, we explore the evolution of global marine redox chemistry using U isotopes of marine limestones. The δ238U trends at Long'an section in South China document systematic oscillations with three negative shifts punctuated by two positive events in between. The magnitude of the δ238U oscillations implies that the sediments do not record contemporaneous seawater with a constant offset at all times. The lack of covariation between δ238U data and diagenetic indicators (e.g., Mn and Sr contents, Mn/Sr ratio, δ18O) suggests that the δ238U trends are not produced by the same post-depositional diagenetic processes. Instead, trace-metal enrichments suggest that more reducing conditions prevailed during the deposition of the two positive events. We present plausible model scenarios that fit the observed δ238U trends in the context of redox-sensitive trace metal data suggesting marine anoxia expanded in the latest Devonian oceans to cover >5% of the continental shelf seafloor area. The rapid expansion of marine anoxia coincident with the onset of the Hangenberg Crisis supports marine anoxia as an important kill mechanism. Biogeochemical modeling of the coupled C-P-U cycles suggests that intensified continental weathering, for example, assisted by the spread of seed plants with deeper root systems at this time, could have triggered expansion of marine anoxia and other global changes (e.g., positive excursion in δ13Ccarb and decrease in sea surface temperature) in the latest Devonian. The anoxic event is inferred to have been transient as climatic cooling would have reduced weathering fluxes.Zhang, H., Diao, R., Mostofi, M., Evans, B., 2019. Monte Carlo simulation of the adsorption and displacement of CH4 by CO2 injection in shale organic carbon slit micropores for CO2 enhanced shale gas recovery. Energy & Fuels 34, 150-163. displacement process of CH4 by the CO2 injection in the shale micropores plays a dominant role in the CO2 enhanced shale gas recovery (CO2-ESGR). In this paper, we have addressed the displacement of CH4 by CO2 in the micropores, and particularly, we have investigated the contribution of each specific pore size from 0.50 to 2.0 nm to the competitive adsorption of CH4 and CO2 in terms of the CH4 recovery and residual CH4 and CO2 adsorption after the displacement. The results showed that the micropores have different contributions to the CH4 recovery depending on the pore size, CO2 ratio, temperature, and pressure. The pores below 0.61 nm make no contribution to CH4 recovery, but the 0.55–0.60 nm pores are beneficial for CO2 storage. The 0.65–0.70 nm pores show the highest CH4 storage capacity and a high selectivity for CO2. As a result, the CH4 recovery reaches the maximum and is not affected by CO2 ratio. Besides, the pores above 1.3 nm provide little to the CH4 recovery at lower pressures, and the injected CO2 ratio changes the optimum pore size in terms of the maximum CH4 recovery. The pore size for the maximum CH4 recovery decreases slightly with the increase of pressure. In addition, the CH4 recovery density is higher at lower temperatures due to higher preadsorption of CH4 and lower residual CH4 capacity. Furthermore, the distribution of the adsorbed CH4 and CO2 after the displacement showed that the residual CH4 distribution is not affected by the injected CO2 and is randomly located among the adsorbed CO2 molecules.Zhang, H., Huang, H., Li, Z., Liu, M., 2020. Comparative study between sequential solvent-extraction and multiple isothermal stages pyrolysis: A case study on Eocene Shahejie Formation shales, Dongying Depression, East China. Fuel 263, 116591. and thermal extractions were performed on a suite of 23 shale core samples, from the Eocene Shahejie Formation of the Dongying Depression, East China, to investigate the Oil-In-Place of shales and the difference among various assessment approaches. The novel multiple isothermal stages (MIS) pyrolysis [Romero-Sarmiento et al., AAPG European Regional Conference & Exhibition. Lisbon; 2015] derives four peaks characterizing the light, light to medium, heavier- and non- hydrocarbons, and the pyrolyzed hydrocarbon (i.e., hydrocarbons derived from thermal decomposition of kerogen), respectively. Compared with standard Rock-Eval pyrolysis on OIP estimation, the MIS pyrolysis provides more specific information concerning gross compositions and physical status of oils, which reduces the impact of the frequently-occurred carryover effect to a certain extent. Systematic variations of molecular compositions especially the light vs. heavy n-alkanes have been elucidated. The mobile oil estimated from MIS pyrolysates is very close to solvent extractable oils (i.e., bitumen). Abnormal increase of pyrolysis hydrocarbons after initial extraction is attributed to the mineral matrix effect. This study demonstrated discrepancies between various approaches in assessment of thermo-vaporizable and pyrolysis hydrocarbons within shale reservoirs and triggered a re-understanding on the application of pyrolysis parameters in shale oil systems.Zhang, H., Jiang, Y., Zhou, K., Fu, Y., Zhong, Z., Zhang, X., Qi, L., Wang, Z., Jiang, Z., 2019. Connectivity of pores in shale reservoirs and its implications for the development of shale gas: A case study of the Lower Silurian Longmaxi Formation in the southern Sichuan Basin. Natural Gas Industry 39, 22-31. Chinese. The unconnected gas-bearing pores in shale gas reservoirs may be transformed into "potential recoverable pores" after largescale hydraulic fracturing. However, the mainstream pore classification methods of shale gas reservoirs, do not take the unconnected pores into account, which impacts the evaluation accuracy of reservoir pore effectiveness. To solve this problem, this paper took the shale of Lower Silurian Longmaxi Formation in the southern Sichuan Basin as the research object to carry out experiments on core porosity, centrifugal + gradual drying NMR after saturated with brine and NMR freeze-thaw using plunger samples and fragmented samples to analyze the volume, main development location and main pore size distribution range of unconnected pores. Then, the pore systems were classified, and the lower limit of effective pore size of connected gas-bearing pores was determined. Finally, the total pore effectiveness of shale gas reservoirs was evaluated, and the influence of unconnected pores on the development of shale gas was discussed. And the following research results were obtained. First, there are a large number of unconnected pores in the shale gas reservoirs of the study area, accounting for 30.23%. Most of them are mainly developed in organic matters and a few are developed in clay minerals. The distribution of pore size ranges from 5 nm to 30 nm. Second, T2 cut-off value of clay bound water in the shale gas reservoirs of the study area is 0.26 ms, whose corresponding pore size is 5.35 nm, which is the lower limit of the effective pore size. Third, large-scale hydraulic fracturing can improve the unconnected pores with the size more than 5.35 nm, so effective development of shale gas will be realized. Fourth, after hydraulic fracturing stimulation, the unconnected pores can increase the storage space of fracturing fluid in the matrix, absorb the fracturing fluid in the fractures, replace the shale gas in the pores and promote the automatic alleviation of water lock in shale gas reservoirs, so the single-well shale gas production will be increased. In conclusion, fluid occurrence and pore system in shale pores can be quantitatively divided by means of centrifugal + gradual temperature drying method combined with NMR experiments, movable water and capillary bound water can be determined by the high speed centrifugal + NMR experiments, and capillary bound water and clay bound water can be determined by the gradual drying + NMR experiments. Zhang, K., Jia, C., Song, Y., Jiang, S., Jiang, Z., Wen, M., Huang, Y., Liu, X., Jiang, T., Peng, J., Wang, X., Xia, Q., Li, B., Li, X., Liu, T., 2020. Analysis of Lower Cambrian shale gas composition, source and accumulation pattern in different tectonic backgrounds: A case study of Weiyuan Block in the Upper Yangtze region and Xiuwu Basin in the Lower Yangtze region. Fuel 263, 115978. shale gas exploration in southern China has successes and failures. Under the condition of great hydrocarbon generation material basis, shale gas wells drilled from some shale gas blocks are rich in methane, while the wells in other shale gas blocks with high nitrogen and low hydrocarbon gas, which indicates that they have different accumulation mechanisms. Therefore, the study of gas composition in shale will help us to figure out the mechanism of shale gas accumulation and loss. In this paper, the Lower Cambrian shale from Wei-201 well in Upper Yangtze Weiyuan Block and Jiangye-1 well from Lower Yangtze Xiuwu Basin are selected as research object, and shale samples are used for tests and experiments including analysis of gas composition and nitrogen isotope, test of porosity and TOC content, overburden permeability test, permeability test before and after methane adsorption under different osmotic pressure, permeability test parallel and vertical to the bedding surface, FIB-SEM (Focus Ion Beam Scanning Electron Microscope) and FIB-HIM (Focused Ion Beam Helium Ion Microscope). Finally, the reasons for the difference in the gas components of the Lower Cambrian shale gas in Weiyuan Block and Xiuwu Basin are studied by means of seismic interpretation, core description and outcrop observation besides the tests and experiments. The results show that the gas components of the Lower Cambrian shale in Weiyuan Block, the Upper Yangtze, mainly consist of methane, derived from liquid hydrocarbon cracking. The sealing capacity of roof and floor, the great self-sealing of shale and the flat anticline structure contribute to the high methane content in shale gas. The Lower Cambrian shale gas in Xiuwu Basin, the Lower Yangtze, is mostly nitrogen, which is derived both from atmosphere and deep crust-upper mantle. The detachment layer at the bottom of the Lower Cambrian, the widely developed deep faults and the Jurassic volcanic activity are the reasons for the high nitrogen and low hydrocarbon of shale gas. Based on the above analysis, the patterns are summarized for shale gas accumulation in the simple anticline background and reservoir destruction in the complex syncline background.Zhang, M., Zhang, W., Cheng, Q., Yuan, Q., 2020. Geochemical characteristics and significances of C19-C26 short-chain steranes in crude oils from the Western Qaidam Basin, China. Arabian Journal of Geosciences 13, 106. on biomarker analysis of crude oils from Western Qaidam Basin, the geochemical characteristics and significances of C19-C26 short-chain steranes were investigated. The oils are characterized by unimodal n-alkane distributions with even (C18-C24) predominance, low Pr/Ph (mostly <?0.5), high concentration of gammacerane, and the C35-hopane over the C34-hopane, suggesting high salinity and anoxic conditions typical of a saline lacustrine sedimentary environment. The short-chain steranes, comprising C19 sterane, C21 pregnane and C22 homopregnane as well as C23-C26 steranes were detected in these crude oils. The relative abundance of these individual compounds showed positive correlations; especially C21 pregnane and C22 homopregnane were found to be closely correlated with other short-chain steranes. On the other hand, the C25 sterane displayed general correlation with other short-chain steranes, whereas the C26 sterane exhibit relatively poor correlation. The study of short-chain sterane distributions and of other aliphatic and aromatic compounds indicated that the relative concentration of short-chain steranes within the study area is controlled by multiple factors such as redox conditions of the depositional environment, water salinity, and thermal maturity of organic matter. Apparently, a weak-reducing environment with brackish water seems to contribute to the formation and enrichment of short-chain steranes. The abundances of these compounds relative to regular steranes increase with the increasing maturity of the oils, which may be possibly attributed to thermal stability reasons. Source-related biomarkers uncover the primary origin of short-chain steranes may be related to algae.Zhang, P., Huang, P., Xu, X., Sun, H., Jiang, B., Liao, Y., 2020. Spectroscopic and molecular characterization of biochar-derived dissolved organic matter and the associations with soil microbial responses. Science of The Total Environment 708, 134619. organic matter (DOM) released from biochar can influence the microbial community structure, but the inherent mechanism associated with the structure of biochar-derived DOM remains insufficiently elucidated. In this study, the spectroscopic characteristics and molecular structures of biochar-derived DOM were studied, and the microbial responses to biochar-derived DOM were explored. With increasing biochar pyrolysis temperature (PT), the molecular weight and proportions of aliphatic and fulvic acid-like compounds in the biochar-derived DOM decrease along with an reduction in the amount of DOM released from the biochars, but the proportions of combustion-derived condensed polycyclic aromatics and humic acid-like and soluble microbial byproduct-like compounds increased. Accordingly, the humification index, H/C and (O+N)/C values also decreased. The spectroscopic characteristics of biochar-derived DOM were distinct from those of natural substrates. Moreover, the DOM extracted from biochar raw materials contained a high proportion of aliphatic compounds, while the DOM derived from high-PT biochars (500 °C) had similar characteristics to fulvic acid-like and soluble microbial byproduct-like compounds. The microbial abundance and community structure varied in different DOM solutions. The relative abundances (RAs) of eight genera (e.g. Dyadobacter, Sphingobacterium and Novosphingobium) had significantly positive correlations with the content of aliphatic compounds, while RAs of seven genera (e.g. Methylotenera, Acinetobacter and Reyranella) had significant positive correlations with the content of high-aromatic combustion-derived condensed polycyclic aromatics. These results are helpful for obtaining a deep understanding of the potential influences of various types of biochar-derived DOM on terrestrial and aquatic microbiology.Zhang, P., Lu, S., Li, J., Chang, X., 2020. 1D and 2D Nuclear magnetic resonance (NMR) relaxation behaviors of protons in clay, kerogen and oil-bearing shale rocks. Marine and Petroleum Geology 114, 104210. 1D T2 and 2D T1-T2 Nuclear magnetic resonance (NMR) studies have focused on oil-bearing shales with complex constituents and a deeper understanding of the NMR relaxation behaviors of oil confined in shale is needed. In this paper, a series of T2 and T1-T2 NMR experiments were performed on oil-bearing shale and its components (clay minerals and kerogen) to obtain the T1-T2 fluid typing chart and analyze the adsorbed and free oil in shale. The results were as follows: five types of water (bound, adsorbed, free, crystal and structural water) in clay minerals were qualitatively identified and described by the specific T2 to T1/T2 ratio values, and T1-T2 maps were used to qualitatively indicate the clay type. The T1-T2 fluid typing chart containing the signatures of 8 proton populations in oil-bearing shale was defined and included bulk liquid, macropore (>1000 nm) oil, nanopore (<1000 nm) oil, and free water in clay minerals or kerogen, shale pore water, bound water in clay minerals, kerogen and crystal water. Adsorbed oil was mainly confined in nanopores, especially micropores smaller than 100 nm, while free oil composed of movable and irreducible oil was predominant in mesopores (100–1000 nm) and macropores. Furthermore, the proportion of irreducible oil gradually decreased and that of movable oil gradually increased from mesopores to macropores. The results demonstrate that the T1-T2 NMR technique may be an effective method for the assessment of fluid distributions and proton mobility and has potential applications for the characterization of shale oil occurrence states.Zhang, Q., Wang, W.-D., Kade, Y., Wang, B.-T., Xiong, L., 2020. Analysis of gas transport behavior in organic and inorganic nanopores based on a unified apparent gas permeability model. Petroleum Science 17, 168–181. from the conventional gas reservoirs, gas transport in nanoporous shales is complicated due to multiple transport mechanisms and reservoir characteristics. In this work, we presented a unified apparent gas permeability model for real gas transport in organic and inorganic nanopores, considering real gas effect, organic matter (OM) porosity, Knudsen diffusion, surface diffusion, and stress dependence. Meanwhile, the effects of monolayer and multilayer adsorption on gas transport are included. Then, we validated the model by experimental results. The influences of pore radius, pore pressure, OM porosity, temperature, and stress dependence on gas transport behavior and their contributions to the total apparent gas permeability (AGP) were analyzed. The results show that the adsorption effect causes Kn(OM)?>?Kn(IM) when the pore pressure is larger than 1 MPa and the pore radius is less than 100 nm. The ratio of the AGP over the intrinsic permeability decreases with an increase in pore radius or pore pressure. For nanopores with a radius of less than 10 nm, the effects of the OM porosity, surface diffusion coefficient, and temperature on gas transport cannot be negligible. Moreover, the surface diffusion almost dominates in nanopores with a radius less than 2 nm under high OM porosity conditions. For the small-radius and low-pressure conditions, gas transport is governed by the Knudsen diffusion in nanopores. This study focuses on revealing gas transport behavior in nanoporous shales.Zhang, S., Li, Y., Pu, H., 2020. Studies of the storage and transport of water and oil in organic-rich shale using vacuum imbibition method. Fuel 266, 117096. inorganic pores, organic pores, and kerogen matrix are important media to store water and oil in shale rocks. We present a vacuum imbibition method to identify the volume of water and oil in these media. Before the experiments, comprehensive rock characterizations were carried out on shale samples from Shahejie Formation combining various methods including N2 adsorption, scanning electron microscope (SEM), X-ray diffraction, and RockEval pyrolysis. Total organic carbon (TOC) accounts for 1.59–5.97% of total rock weight. Kerogen thermal maturity (Ro) of the studied samples is 0.62–1.05%. Then, vacuum imbibition experiments were conducted on shale samples using water and n-dodecane. The accurate volumes of water in organic pores, oil in inorganic pores and organic pores, and the volume of dissolved oil were determined from vacuum imbibition experiments. The effects of Ro on shale storage were analyzed. Furthermore, novel mathematical models of oil and water vacuum imbibition in shale were proposed. The water imbibition in inorganic pores is a capillary flow. The oil imbibition in shale includes capillary flow in pore structures and diffusion in kerogen. The pore-kerogen double diffuse layer (PKDDL) physical model was proposed for the mechanisms of the hydrocarbon mass transfer between pore structures and kerogen. The capillary pressure and the dissolution rate constants were obtained by matching mathematical models with experimental results. This study provides new methods to evaluate the water and oil storage and transfer in organic-rich shale and advances the crucial mechanisms for the evaluation and development of shale reservoirs.Zhang, W., Liang, J., Wei, J., Lu, J.a., Su, P., Lin, L., Huang, W., Guo, Y., Deng, W., Yang, X., Wan, Z., 2020. Geological and geophysical features of and controls on occurrence and accumulation of gas hydrates in the first offshore gas-hydrate production test region in the Shenhu area, Northern South China Sea. Marine and Petroleum Geology 114, 104191. three-dimensional seismic, logging, sediment cores, and geochemical testing data were collected from Guangzhou Marine Geological Survey 3 and 4 hydrate drilling expeditions and used in this study for a comprehensive investigation of the geological and geophysical features and accumulation mechanism of hydrates in the first offshore gas-hydrate production test region (GHPTR) in the Shenhu area of the South China Sea. Seismic signatures indicative of disseminated hydrates and free gas include the bottom simulating reflector (BSR), gas chimney, and mud diapir associated with enhanced seismic reflections, acoustic blanking, masking, and chaotic appearance have been observed. The acoustic travel-time responses, density, and compensated neutron three porosity log analysis, high-precision grid tomography inversion analysis, and constrained sparse spike inversion confirm the presence of free gas below the gas-hydrate-bearing zone (GHBZ). Free-gas-bearing zones have significantly different p-wave impedances and low-velocity anomalies than the overlying GHBZ and surrounding strata. These anomalous zones are controlled by the structural attitude of the reservoir strata, which are characterized as inter-bedded stratigraphic units. Variations in the type and geological characteristics of the hydrocarbon migration pathways were observed between sites W18 and W19 on the western ridge and sites W11 and W17 on the eastern ridge in the GMGS study area. The efficiency of gas migration in the western ridge may be higher than that in the eastern ridge, resulting in variations in hydrate gas types, thickness of the GHBZ, and gas migration flux and accumulation. Except for site W11, hydrates were recovered below the structure I inferred BSR at sites W17, W18, and W19. The gas-hydrate stability zone calculations reveal that the structure I hydrate stability zone differs from the BSR depth and is generally shallower than the base of the logging anomaly, indicating the coexistence of structure I and II hydrates. The BSR is not indicative of the BGHSZ; it is rather regarded as a transitional indicator of structure I and II gas hydrates in the GHPTR. The appearance of free gas and hydrates below the structure I inferred BSR indicates that the Shenhu area is characterized by a complex hydrate formation and accumulation system resulting from the supply of biogenic and thermogenic gases. Despite fine-grained host sediments predominating the GHPTR, the coupling of favorable conditions including efficient hydrocarbon generation, sufficient gas supply, multiple pathways for gas migration, and relatively high reservoir porosity have led to the development of highly saturated gas-hydrate accumulations within relatively thick sedimentary sections, which demonstrates a significant resource potential.Zhang, X., Li, S., Yan, M., Wang, X., Geng, G., 2020. Early Cretaceous black shale in the Fajiaying Formation (Lingshan Island, East China): Terrestrial record of hothouse climate. Journal of Asian Earth Sciences 191, 104200. significance of Cretaceous hothouse climate in terrestrial systems is currently unclear, and its records in terrestrial strata are rarely reported. This study investigated the sedimentary environment of the Fajiaying Formation, characterised by abundant black shale and soft-sediment deformation structures. Five lithofacies have been identified for the Fajiaying Formation, e.g. Facies A: black shale with siltstone inter-bedding, Facies B: black and gray-black shale and siltstone alternations with minor sandstone, Facies C: black and gray-black shale interbedded with gray-black sandstone, Facies D: pebbly sandstone and Facies E: gray-black shale and siltstone. The average TOC content of the shales decreases from facies A (av. 1.32%) to facies E (av. 0.46%) through facies B (av. 0.57%) and facies C (av. 0.40%). The paleosalinity gradually decreases from lithofacies A to lithofacies E, corresponding to the change of paleoclimate. In addition, Bivariate Scatter Plot of SiO2 and Al2O3 + K2O + Na2O and the clay mineral assemblages suggest an arid climate. Combined with distribution characteristics and paleontology of saliferous strata in eastern China, we determine that hothouse climate influenced the salification of lakes located in eastern China during the Early Cretaceous. Furthermore, the Fajiaying Formation in Lingshan Island was deposited in a terrestrial salified lake. Salinization of the sedimentary water bodies of the Fajiaying Formation might be related to an oceanic anoxic event. The black shale developed extensively in the Fajiaying Formation and represents the terrestrial record of hothouse climate.Zhang, X., Mell, A., Li, F., Thaysen, C., Musselman, B., Tice, J., Vukovic, D., Rochman, C., Helm, P.A., Jobst, K.J., 2020. Rapid fingerprinting of source and environmental microplastics using direct analysis in real time-high resolution mass spectrometry. Analytica Chimica Acta 1100, 107-117. are ubiquitous in the aquatic and terrestrial environment. To prevent further contamination, methods to determine their sources are needed. Techniques to quantify and characterize microplastics in the environment are still evolving for polymers and the additives and leachable substances embedded therein, which constitute the “chemical fingerprint” of an environmental microplastic. There is a critical need for analytical methods that yield such diagnostic information on environmental microplastics that enables identification of their composition and sources of pollution. This study reports on a novel approach for rapid fingerprinting of environmental microplastics and the screening of additives using Direct Analysis in Real Time (DART)-high resolution mass spectrometry. A variety of plastic samples were investigated, including virgin pre-production pellets, microbeads from personal care products, microplastics found in the aquatic environment, and synthetic fibers. The resulting mass spectra display ～10,000 discrete peaks, corresponding to plastic additives released by thermal desorption and polymer degradation products generated by pyrolysis. These were used to characterize differences among plastic types, microplastic source materials, and environmental samples. Multivariate statistics and elemental composition analysis approaches were applied to analyze fingerprints from the mass spectra. This promising analytical approach is sensitive, (potentially) high-throughput, and can aid in the elucidation of possible sources of microplastics and perhaps eventually to the analysis of bulk environmental samples for plastics.Zhang, X., Zhou, X., Hu, D., 2020. High-resolution paired carbon isotopic records from the Meishucun section in South China: Implications for carbon cycling and environmental changes during the Ediacaran-Cambrian transition. Precambrian Research 337, 105561. prominent negative carbon isotope (δ13C) excursions are observed during the Ediacaran-Cambrian (E-C) transition, reflecting large perturbations of the carbon cycle in the ocean–atmosphere system. These negative δ13C excursions have been linked to dramatic paleoenvironmental changes and been widely used as regional and global chemostratigraphic correlation tools. However, there is still much debate about their causes and mechanisms. In this study, we report high-resolution δ13C records of both carbonate (δ13Ccarb) and organic carbon (δ13Corg) from the Meishucun section in South China. Combined with lithological variations and intrabasinal correlations, we find that the negative δ13C excursions during the E-C transition in South China are tightly linked with transgressive events. The existence of a large vertical (surface-to-deep water) δ13C gradient in a stratified ocean, and episodic incursions of 13C-depleted anoxic/euxinic deep waters into shallow water environment through enhanced upwelling or shoaling of the chemocline, may have contributed to these negative δ13C excursions. In addition, our results also imply a large reduction in the vertical δ13Corg gradient during the E-C transition, which may reflect the ventilation and oxygenation of the deep ocean. The corresponding expansion of oxic seafloor conditions and a large increase in the extent of habitable space for animals may have facilitated the radiation of metazoans during the Cambrian explosion.Zhang, Y.-Y., Wei, X.-Y., Lv, J.-H., Jiang, H., Liu, F.-J., Liu, G.-H., Zong, Z.-M., 2019. Characterization of nitrogen-containing aromatics in Baiyinhua lignite and its soluble portions from thermal dissolution. Chinese Journal of Chemical Engineering 27, 2783-2787. portions (SPs) 1–4 (SP1-SP4) were afforded from sequentially dissolution and alkanolyses of Baiyinhua lignite (BL) in cyclohexane, CH3OH, CH3CH2OH, and (CH3)2CHOH at 300?°C. They were analyzed with a gas chromatograph/mass spectrometer and quadrupole exactive orbitrap mass spectrometer (QEOTMS) with an atmosphere pressure chemical ionization source in positive-ion mode, while BL was characterized with an X-ray photoelectron spectrometer (XRPES). The results show that the yields of SP2 and SP3 are much higher than those of SP1 and SP4, and the total SP yield is ca. 39.0%. According to the results of the analysis with XRPES, pyrrolic nitrogens are the most abundant nitrogen existing forms in BL. Thousands of nitrogen-containing aromatics (NCAs) were resolved with QEOTMS and their molecular masses are mainly in the range of 200–450 u. The main NCAs are N1O1 and N1O2 class species with double bond equivalent values of 4–18 and carbon number of 7–30. The nitrogen atoms appear in pyridines, quinolines, benzoquinolines or acridine, and dibenzoquinolines or naphthoquinolines, while the oxygen atoms exist in methoxy and furan rings.Zhang, Y., Fang, T., Ding, B., Wang, W., Yan, Y., Li, Z., Guo, W., Zhang, J., 2020. Migration of oil/methane mixture in shale inorganic nano-pore throat: A molecular dynamics simulation study. Journal of Petroleum Science and Engineering 187, 106784. shale reservoirs, crude oil always involves a varying percentage of methane gas that may greatly affect the properties and the migration behavior of crude oil. In this work, to evaluate the effect of methane gas and to clarify the molecular mechanisms, the migration of oil/gas mixture in shale channels was characterized using molecular dynamics (MD) simulations. Specifically, the transport of oil with different methane fractions in a shale inorganic nano-pore throat was simulated. With analyzing the force that the oil undergoes when going across the nano-pore, the oil dynamic transport feature for different methane fractions was clarified. Then, the interfacial tension, the diffusion coefficient, and the interaction energy were calculated to give insights into the methane effects on oil transport. In addition, other oil-associated gases (ethane and propane) and the effect of temperature were studied and discussed. This work expands our knowledge of the oil and gas transport in nano-pore throat at the molecular level, and it is expected to facilitate future studies on the migration of fluids through space-confined channels.Zhang, Y., Yu, J., Su, Y., Du, Y., Liu, Z., 2020. A comparison of n-alkane contents in sediments of five lakes from contrasting environments. Organic Geochemistry 139, 103943. paleolimnology studies, the trajectories of n-alkane abundances and distributions in dated sediments are widely used indicators of changing environmental and ecological status in the overlying water over time. However, the factors contributing to the variable n-alkane profiles of lake systems are not yet fully understood. Here, a comparative study was conducted to examine natural and anthropogenic influences on the sediment n-alkane profiles of five representative lakes in China. Core samples from the deep oligo- mesotrophic lakes Fuxian and Lugu (FX-1 and LG-1 cores), the shallow eutrophic lakes Taibai and Changdang (TB-1 and CD-1 cores) and the alpine Lake Heihai (HH-1 core) were used. While there were striking differences in n-alkane abundances and distributions between the cores, the results suggested that the n-alkanes in all five studied lakes were derived mainly from biogenic sources, rather than from petroleum contamination. The short-chain (<C20) even carbon n-alkanes, assumed to derive from non-photosynthetic bacteria, were especially prevalent in FX-1, reaching 158.3–284.4 μg/g TOC, which might be a result of high levels of bacterial productivity in the deep (average 89.6?m) water column of Lake Fuxian. The contribution of bacterial production diminished in the other four lakes, with <C20 n-alkanes declining to between 21.4 and 60.5 μg/g TOC on average in the studied cores. In the two shallow lakes, abundances of short-chain (<C20) odd carbon n-alkanes were greatly elevated in sediments corresponding to the eutrophic phase; for example, with maximum values of 136.3 μg/g TOC recorded in TB-1. This nutrient-driven effect was less apparent in deep lakes. The >C21 n-alkane profiles of different cores varied significantly. Abundances of long-chain n-alkanes (C29, C31 and C33) in HH-1 were approximately 3–7 times greater than in other cores. Coupled with the lowest Paq (average 0.29) values recorded in the study, this indicates a predominantly terrestrial plant origin for the >C21 n-alkanes, most likely the dense alpine meadow which surrounds the lake. In other cores, however, aquatic macrophytes appear to be more important contributors of the n-alkanes, a result that corresponds with the relatively low density of terrestrial plants in those catchments.Zhao, B., Li, R., Qin, X., Liu, F., Wu, X., Zhao, D., Liu, Q., Zhou, W., 2019. Characteristics of shale reservoirs in the Upper Paleozoic Shanxi Formation, Central Ordos Basin. Acta Sedimentologica Sinica 37, 1140-1151. Formation shale is a stratum of marine-continental transitional facies with potential for shale gas exploration in the Ordos Basin. The petrology, mineralogy,reservoir space,pore structure and reservoir quality of the shale show that Shanxi Formation shale comprises black mud shale,grey-black mudstone and dark grey silty mudstone. It mainly consists of 59.6% clay minerals and 36.9% quartz,on average. Fractures are classified into macroand microfractures;the latter mainly occur in the shale and organic macerals, with an average surface density of 116.6/m. In addition to mineral and diagenetic pores,organic pores occur in organic macerals,formed by hydrocarbon generation as a result of the high degree of thermal evolution. Shanxi Formation mud shale has an average porosity of 0.77% and an average permeability of 0.06×10-3 μm2.A positive correlation was found between total organic carbon (TOC), vitrinite reflectance(Ro) and clay mineral content;quartz content and shale porosity are negatively correlated. The general development of fractures increases the permeability of shale,favorable to the accumulation of shale gas. Comprehensive analysis shows that the geological conditions of the shale gas reservoir in the Shanxi Formation are general and difficult to develop. However,there are good prospects for shale gas in the layers and regions with fractures and associated properties.Zhao, J., Wang, G., Chu, J., Zhuang, Y., 2019. Harnessing microbial metabolomics for industrial applications. World Journal of Microbiology and Biotechnology 36, 1. defines a set of metabolites present in a biological sample, which provides an immediate and dynamic recording of microbes in response to genetic and/or environmental perturbations. In recent years, metabolomics in combination with other omics diagnostic tools such as genomics, transcriptomics and proteomics is focused on addressing open biological questions that accelerate our understanding of the system as a whole and boost the use of systems metabolic engineering tools in industrial settings. In this review article, we summarize the applications of metabolomics to industrial microbial fermentations with respect to the bulk production of organic acids, amino acids, enzymes, antibiotics and therapeutic proteins. In addition, future prospects regarding metabolomics-assisted research are provided.Zhao, P., Fu, J., Shi, Y., Li, G., Ostadhassan, M., Luo, M., Mao, Z., 2020. Hydrocarbon saturation in shale oil reservoirs by inversion of dielectric dispersion logs. Fuel 266, 116934. saturation is an important petrophysical parameter in reservoir evaluation and reserve calculation. Dielectric dispersion logs have been widely used to estimate the hydrocarbon saturation, especially in high salinity shale formations. However, there is still room to improve the accuracy of interpretation of dielectric dispersion logs. In this paper, we used two interpretation models combined four dielectric permittivity and four conductivity logs measured by Array Dielectric Tool (ADT) at four frequencies to predict the hydrocarbon saturation in shale oil reservoirs, Triassic Yanchang Formation, Ordos Basin, China. The logs measured at the highest frequency are interpreted by the Complex Refractive Index (CRIM) model. And the other three frequencies measured logs are processed by the shaly sandstone (SHSD) model. Based on the two models, simulated annealing algorithm is selected to calculate water saturation and rock textual parameter, the dispersive phase fraction, and water salinity. Besides, accurate porosity, dielectric permittivity of rock matrix, and temperature are input information to the proposed method. The proposed method is applied to shale oil reservoirs of Triassic Yanchang Formation in two wells. The effectiveness and reliability of proposed model is verified by synthetic log responses. The mean relative error between synthetic and field logs is small. The predicted hydrocarbon saturation is consistent with core data, and its variation is consistent with characteristics of NMR T2 distributions, verifying the accuracy and reliability of proposed method and inversion results. Our estimated hydrocarbon saturation of the two wells is about 30%, showing a good oil generation potential of the studied shale oil reservoirs.Zhao, Q., Guo, L., Wang, Y., Jin, H., Chen, L., Huang, Z., 2020. Enhanced oil recovery and in situ upgrading of heavy oil by supercritical water injection. Energy & Fuels 34, 360-367. oil accounts for two-thirds of the world oil resources but contributes only one-seventh of the world oil production due to its high oil viscosity and heavy distillates. Steam injection has been widely used for heavy oil recovery by heating up the reservoir to reduce oil viscosity. However, severe carbon loss to coking causes low recovery efficiency and high energy consumption. Here, we report supercritical water injection for heavy oil recovery. Supercritical water is expected to be both a heat carrier and an organic solvent, thereby not only reducing oil viscosity but also dissolving heavy distillates to avoid coking. To test its feasibility, core experiments were first conducted to simulate the recovery process. Results showed that supercritical water flooding improved oil recovery by 17% and reduced heat consumption by 34% versus classsical steam flooding. Further, to clarify its recovery mechanism, a visualization technique and a quantitative method were developed for regulating phase behaviors and upgrading reactions between heavy oil and supercritical water. Results showed that supercritical water has good miscibility with heavy oil, and it is the key to both enhanced oil recovery and in situ upgrading. High miscibility means formation of supercritical water clusters around organic macromolecules, which makes asphaltene difficult to aggregate and polymerize to form coke but easy to decompose to form maltene and recover. Overall, supercritical water injection has made great advances in enhanced oil recovery, energy saving, and in situ upgrading for heavy oil recovery. The work provides a sound basis for its application in oilfields.Zhao, S., Sun, Y., Lü, X., Li, Q., 2020. Energy consumption and product release characteristics evaluation of oil shale non-isothermal pyrolysis based on TG-DSC. Journal of Petroleum Science and Engineering 187, 106812. Scanning Calorimetry Analysis (TG-DSC) was applied to study non-isothermal pyrolysis characteristics of oil shales, such as the starting point, stability, pyrolysis interval and product release using Fuyu and Huadian oil shale samples. Results show that with the increase of heating rate, oil shale pyrolysis moves to higher temperature zone. This trend is more noticeable at higher oil content. The pyrolysis stability of the oil shale is related to oil content and pyrolysis atmosphere. The higher the oil content, the more stable the pyrolysis of the oil shale. Under nitrogen atmosphere, the pyrolysis interval of oil shale is more concentrated, air prolongs the pyrolysis interval, and the pyrolysis stability index decreases. In addition, the increase of heating rate favours the release characteristic index of the product, which is not practically affected by oil content. The release characteristic indices of pyrolysis products from oil shale under nitrogen atmosphere are higher than those under air atmosphere. The optimum heating rate that produces the highest oil product yield for pyrolysis progress of Huadian oil shale is 20?°C/min, and Fuyu oil shale is 40?°C/min.Zheng, M., Liu, T., Jiang, G., Wei, M., Huo, Y., Liu, L., 2020. Large-scale and high-similarity experimental study of the effect of drilling fluid penetration on physical properties of gas hydrate-bearing sediments in the Gulf of Mexico. Journal of Petroleum Science and Engineering 187, 106832. this study, the process of drilling fluid penetrating into gas hydrate-bearing sediments in the Gulf of Mexico Hydrate Joint Industry Project was simulated with conditions similar to in situ drilling process parameters and reservoir temperatures and pressures. Natural sediments were replaced by artificial sediments columns with approximately similar physical properties. The temperature, pressure, and resistivity were measured in real time, and the effects of drilling fluid penetration on the physical properties were analyzed. The hydrate saturation, penetration depth, and influence mechanism of temperature and pressure difference were obtained. By orthogonal analysis, the porosity and resistivity of the artificial sediments columns were found to be optimized closely to natural conditions, with a difference of 1.29% and 4.0%, respectively. During penetration, a positive pressure difference was useful for maintaining hydrate stability, while the temperature difference had an opposite influence. High density, low temperature, and low filtration loss drilling fluid were found to be beneficial for field drilling. Hydrate decomposition gradually occurred with increasing depth, accompanied by reformation. The front edge of resistivity lagged behind the pressure and temperature, with a depth of ~0.65?m. Therefore, for resistivity logging after drilling, logging methods with a coordinated detection depth should be considered; thus, a dual laterolog with deep focused resistivity measurements would be a better choice.Zhou, A., Weber, Y., Chiu, B.K., Elling, F.J., Cobban, A.B., Pearson, A., Leavitt, W.D., 2020. Energy flux controls tetraether lipid cyclization in Sulfolobus acidocaldarius. Environmental Microbiology 22, 343-353. regulate the composition of their membranes in response to environmental cues. Many Archaea maintain the fluidity and permeability of their membranes by adjusting the number of cyclic moieties within the cores of their glycerol dibiphytanyl glycerol tetraether (GDGT) lipids. Cyclized GDGTs increase membrane packing and stability, which has been shown to help cells survive shifts in temperature and pH. However, the extent of this cyclization also varies with growth phase and electron acceptor or donor limitation. These observations indicate a relationship between energy metabolism and membrane composition. Here we show that the average degree of GDGT cyclization increases with doubling time in continuous cultures of the thermoacidophile Sulfolobus acidocaldarius (DSM 639). This is consistent with the behavior of a mesoneutrophile, Nitrosopumilus maritimus SCM1. Together, these results demonstrate that archaeal GDGT distributions can shift in response to electron donor flux and energy availability, independent of pH or temperature. Paleoenvironmental reconstructions based on GDGTs thus capture the energy available to microbes, which encompasses fluctuations in temperature and pH, as well as electron donor and acceptor availability. The ability of Archaea to adjust membrane composition and packing may be an important strategy that enables survival during episodes of energy stress.Zhou, H., Chen, J., Li, H., Quan, K., Zhang, Y., Qiu, H., 2020. Imidazolium ionic liquid-enhanced poly(quinine)-modified silica as a new multi-mode chromatographic stationary phase for separation of achiral and chiral compounds. Talanta 211, 120743. this work, a novel imidazolium ionic liquid-functionalized poly(quinine)-modified silica stationary phase (Sil-PQn-MIm) was successfully synthesized via surface radical chain transfer and nucleophilic substitution reaction. The modified silica was confirmed by series of characterizations including Fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The multi-mode chromatographic performances of the Sil-PQn-MIm column were investigated by anion-exchange mode for separation of aromatic acid samples, hydrophilic interaction mode for separation of nucleosides/nucleobases and sulfanilamides, and reversed-phase mode for separation of alkylbenzenes, benzene and polycyclic aromatic hydrocarbons (PAHs), and the Tanaka test mixtures, respectively. As expected, compared to the Sil-PQn column only with quinine as functional group, the Sil-PQn-MIm column further modified by imidazolium ionic liquid possessed higher separation performance, especially for the separation of nucleosides/nucleobases. The effects including buffer concentration, pH, organic solvent content and column temperature on chromatographic performance were studied, which proved that multiple interactions including electrostatic, hydrophobic and hydrophilic interactions can be simultaneously existed between the stationary phase and the analytes. In addition, reproducibility and efficiency of the Sil-PQn-MIm column were also investigated, the results illustrated that the stationary phase have good enough reproducibility (RSDs 0.15%–0.72%, n?=?7) and high efficiency (plates per meter, ~90000 plates/m). In conclusion, the prepared stationary phase with multiple-mode retention capabilities could realize separation for various types of samples by optimizing chromatographic conditions, even for some chiral compounds.Zhou, J., Yang, K., Tian, S., Zhou, L., Xian, X., Jiang, Y., Liu, M., Cai, J., 2020. CO2-water-shale interaction induced shale microstructural alteration. Fuel 263, 116642. better understand the CO2 enhanced shale gas recovery process, it is of great significance to investigate the CO2-water-shale interaction and its effect on the microstructural alteration in shale. To clarify the microstructural alteration of shale exposure to CO2-water at different CO2 pressures, X-ray diffraction analysis, low-pressure nitrogen gas adsorption (N2GA), nuclear magnetic resonance (NMR) and fractal analysis were carried on shale samples before and after pure water and CO2-water (PCO2 = 6, 10, 14 MPa; T = 45 °C) exposure. After CO2-water exposure, the contents of quartz in shale were increased, while the content of carbonate and clay minerals in shale were decreased with the increase of CO2 pressure. With the increase of CO2 pressure, the total specific surface area (TSSA) in shale were decreased with a maximum reduction of 29.40%, while the porosity was increased from 2.88% to a range of 2.93%-3.16%. The average pore size (Rave) in shale was also increased and the pore connectivity in shale was improved, micropores and mesopores in shale are gradually transferred to macropores. Both the pore surface fractal dimensions obtained from N2GA (DL1) and NMR (DN1), and the pore volume fractal dimensions obtained from N2GA (DL2) and NMR (DN2), were shown a reduction tendency with the increase of CO2 pressure, which reflected that the roughness and complexity of pore structure and morphology in shale decreased. The results indicated that the effect of super-critical CO2 (10 MPa, 14 MPa) on the pore structure alteration was more significant than that of sub-critical CO2 (6 MPa). The fractal dimensions calculated by N2GA and NMR tests had a good consistency, DL1, DN1, and DL2, DN2 shown positive correlations with TSSA and TPV (total pore volume), while shown negative correlations with Rave, which can be used to evaluate the gas adsorption and flow behaviors in shale, respectively.Zhou, K., Zhou, X., Liu, J., Huang, Z., 2020. Application of magnetic nanoparticles in petroleum industry: A review. Journal of Petroleum Science and Engineering 188, 106943. to the exclusive size effect, magnetic nanoparticles (MNPs) exhibit unique chemical, mechanical and considerably different magnetic properties compared with conventional micro and macro materials. Therefore, MNPs are of great significance and interest in biology, medicine and engineering. Recently, MNPs are also found to show great potential in petroleum industry applications, such as targeted adsorption, remote detection, directional transport and local heating. For these specific applications, the dispersity and stability of the MNPs in suspension are of great importance. Although some works have overviewed the use of nanotechnology for oil production, there is no review focusing on the application of MNPs in petroleum industry to date. Thus, recent progress and future developments in this field require for a work to summarize. This review provides an overview on the applications of the MNPs in petroleum industry, including drilling and completion improvement, magnetic separation, reservoir sensing and imaging, enhanced oil recovery, heavy oil recovery, flow assurance and conformance control. The physiochemical properties of MNPs, such as size, surface and magnetic properties, are also introduced. Finally, the main challenges and opportunities regarding the application of the MNPs in this research field are discussed.Zhu, C., Sheng, J.J., Ettehadtavakkol, A., Li, Y., Dong, M., 2020. Numerical and experimental study of oil transfer in laminated shale. International Journal of Coal Geology 217, 103365. is ubiquitous in shale oil reservoirs and significantly influences the oil transfer process. Understanding oil transfer in laminated shale is important for shale oil reservoir development. Therefore, a mathematic model is developed to describe the processes involved in vacuum-imbibition tests. In constructing the mathematic model, viscous flow in inorganic pore, oil adsorption, and absorption in organic matter, and oil diffusion through organic matter surface and interior are considered. In addition, a crucial link between the model and physical characteristics of shale (specific surface area, clay content, and total organic carbon content) is established. The results reveal that the saturation capacities of free oil, adsorbed oil, and absorbed oil in shale depend on the porosity, specific surface area and volume of organic matter, respectively. The oil contents in the adsorption and absorption phase range from 2.2% to 8.3% and 41.8% to 51.4% of the total oil content for the three samples in this study, respectively. When the equilibrium time is used to determine the oil transfer in shale, a larger specific surface area, a smaller thickness of lamination, and smaller volume fractions of organic–clay matrix to total volume of the samples hasten oil transfer. Also, an ideal vacuum-imbibition process of oil in laminated shale is discussed. The results reveal that oil diffusion through the surface of organic matter accelerates the oil transfer in laminated shale. However, the effect of the effectivity diffusion coefficient of oil in the adsorption phase (Ds) on the oil transfer is smaller than that of the effectivity diffusion coefficient of oil in the absorption phase (Dd).Zhu, G., Yan, H., Chen, W., Yan, L., Zhang, K., Li, T., Chen, Z., Wu, G., Santosh, M., 2020. Discovery of Cryogenian interglacial source rocks in the northern Tarim, NW China: Implications for Neoproterozoic paleoclimatic reconstructions and hydrocarbon exploration. Gondwana Research 80, 370-384. Neoproterozoic Earth witnessed major global glaciation events with significant impact on paleoclimate and life evolution. The Tarim Craton in China preserves the records of four glaciation events during the Neoproterozoic which were correlated with the global glaciations, the nature and impact of these with respect to Neoproterozoic paleoclimatic–paleogeographic reconstructions remain unresolved. Here we report the discovery of a suite of source rocks from northeastern Tarim in which the strata formed during 655–635 Ma, corresponding to the interglacial period between the Sturtian and Marinoan diamictites. These source rocks are dominated by black shales and mudstones of up to 300 m thickness, and are characterized by high content of organic matter with TOC (total organic carbon) of 0.46%–3.5% (average 1.64%), vitrinite reflectance Ro of 1.28%–1.60%, and kerogen carbon isotope δ13C value between ?28.58‰ and ?31.89‰. Biomarker compounds indicate that the organic matter in these saprolite source rocks are made up of microorganisms such as algae and bacteria. The Pr and Ph values indicate a weak reducing–oxidizing environment, and most values of CIA (Chemical Index of Alteration) are >68, suggesting an interglacial temperate paleoclimate. The La/Th–Hf and Co/Th–La/Sc relationship suggests that the provenance of these rocks is mainly mixed felsic/mafic rocks. In the Tarim basin, these source rocks comprise an area of up to 90,000 km2 within Cryogenian rifts as inferred from seismic reflection profiles. Based on zircon U-Pb ages of volcanic rocks underlying the shale units, it is inferred the source rock formed during the temperate Sturtian glaciation events with subsequent extensive biotic recovery and high productivity.Zhu, J.-C., Zou, C.-N., Feng, Y.-L., Jiang, S., Wu, W.-A., Zhu, R.-x., Yuan, M., 2020. Distribution and controls of petroliferous plays in subtle traps within a Paleogene lacustrine sequence stratigraphic framework, Dongying Depression, Bohai Bay Basin, Eastern China. Petroleum Science 17, 1-22. characteristics of petroliferous plays in subtle traps within a sequence stratigraphic framework in the Dongying Depression are investigated in this study. Sand bodies within lowstand systems tracts (LSTs) of sequences, comprising incised-channel fills, sublacustrine fans, deltas in LSTs, controlled by syndepositional normal faults, and sand bodies within transgressive systems tracts (TSTs) to early highstand systems tracts (HSTs), consisting of beach bars, and turbidites, controlled by the prodelta slope, paleorelief, and syndepositional normal faults, are good subtle reservoirs. Mudstones and shale of deep lake subfacies in TSTs to early HSTs of sequences are source and cap rocks. Abnormal overpressure is the dominant dynamic factor for hydrocarbon migration from source rock to the subtle traps. Normal faults, sand bodies, and unconformities function as conduit systems. Sand bodies distributed in the abnormal overpressure source rocks within LSTs to early HSTs are petroliferous plays in lithologic traps. The petroliferous plays in stratigraphic traps are controlled by unconformities at margins of the Depression.Zhu, L., Zhang, C., Zhang, C., Zhang, Z., Zhou, X., Liu, W., Zhu, B., 2020. A new and reliable dual model- and data-driven TOC prediction concept: A TOC logging evaluation method using multiple overlapping methods integrated with semi-supervised deep learning. Journal of Petroleum Science and Engineering 188, 106944. total organic carbon content (TOC) is the most important parameter when determining the source rock quality. At present, there are two main types of TOC well logging calculation methods: model-driven and data-driven methods. However, research on the these two types of methods has slowed over the past ten years, and the ongoing research is very limited; thus, it is difficult to improve the TOC calculation accuracy. This paper analyses the advantages and disadvantages of current methods and proposes a new model- and data-driven TOC prediction concept to improve the TOC prediction accuracy. The proposed concept takes the curve obtained with the overlap method as an input instead of using a conventional log curve; we believe that deep learning is best suited to accomplish this task. We propose a new integrated semi-supervised deep learning network—the integrated deep semi-supervised ladder network (IDLN) algorithm—for small-sample well logging interpretation problems based on the proposed approach. A two-step method consisting of intelligent curve overlapping and automatic TOC prediction is employed to better interpret logging data and core data; this method can predict the TOC without manually overlapping curves. Testing the data from 12 wells in 3 blocks revealed that the proposed concept and IDLN algorithm greatly improve the TOC prediction accuracy, and the mean square error was reduced by more than 50%. The new method is also more reasonable for locating non-reservoir segments. Moreover, this novel approach can further enhance the TOC prediction accuracy and may even constitute a new research direction for improving the existing logging interpretation theory. These novel principles can ultimately help evaluate source rock reservoirs.Zhu, Z., Yu, C., Luo, W., Miao, Y., Lu, Z., Liu, L., Yang, J., 2020. Accurate identification of the pastry contained in a ceramic pot excavated from Jurou Li's grave from the Jin dynasty (1115–1234 ce) in Xi'an, Shaanxi, China. Archaeometry 62, 130-140. order to identify accurately the circular object contained in the ceramic pot excavated from Jurou Li's grave of the Jin dynasty (1115–1234 ce) in Xi'an, Shaanxi, China, mass spectrometry was applied to determine the amino acid sequences of the residual proteins extracted from the sample, after preliminary starch grain analysis. The sequences were searched against a standard protein sequence database. The proteins extracted were identified as originating from domesticated barley (Hordeum vulgare), soybean (Glycine max), and fermentative microorganisms (Kluyveromyces lactis, Lipomyces starkeyi, Wickerhamomyces ciferrii, Nadsonia fulvescens and Zygosaccharomyces rouxii). These findings indicate that the extremely degraded object in the ceramic pot was made from barley by fermentation with the addition of soy sauce, providing direct evidence of culinary culture in the Jin dynasty.Ziervogel, K., Arnosti, C., 2020. Substantial carbohydrate hydrolase activities in the water column of the Guaymas Basin (Gulf of California). Frontiers in Marine Science 6, 815. doi: 10.3389/fmars.2019. 00815. Guaymas Basin spreading center situated in the Gulf of California is characterized by a thick layer of organic-rich sediments that are thermally altered by hydrothermal fluids, thereby providing a bottom water source of dissolved organic carbon (DOC) to the water column. The potential for heterotrophic microbial communities in the water column to metabolize this organic matter source has not yet been investigated, however. In order to assess heterotrophic potential in the water column of the Guaymas Basin, we measured the activities of carbohydrate-hydrolyzing extracellular enzymes at the chlorophyll maximum, the oxygen minimum, the deep-water turbidity plume, and bottom waters. These measurements were carried out using water obtained from repeat CTD casts over the course of a week, and from bottom water collected by HOV Alvin at hydrothermally active areas with extensive chemosynthetic microbial mats. Repeat measurements at subsurface depths were very comparable across sampling dates and CTD casts. Exo-acting (terminal-unit-cleaving) monosaccharide hydrolase activities were typically higher in deeper waters than in surface waters, despite colder temperatures. In bottom water, the spectrum of endo-acting (mid-chain-cleaving) polysaccharide hydrolase activities was broader than at shallower depths. The high enzyme activities in Guaymas Basin bottom waters indicate an unusually active heterotrophic community that is responding to influx of DOC and nutrients into bottom waters from the hydrothermally affected sediments, or to the availability of chemosynthetically produced biomass.Zou, J., Rezaee, R., Yuan, Y., Liu, K., Xie, Q., You, L., 2020. Distribution of adsorbed water in shale: An experimental study on isolated kerogen and bulk shale samples. Journal of Petroleum Science and Engineering 187, 106858. shale samples were studied for distribution of adsorbed water using low-pressure nitrogen sorption. By comparing results between dry and wet samples, the distribution of adsorbed water in shale was determined. Two of the isolated kerogen samples show a striking change of pore size distribution (PSD) in large pores (>16?nm), indicating the pronounced distribution of adsorbed water in large pores of organic matter. As for the bulk shale, water can adsorb in both small (<16?nm) and large pores (>16?nm) depending on hydrophilic sites. However, hydrophilic sites in small pores are mainly contributed by inorganic matter, while hydrophilic sites in large pores are composed of inorganic or organic matter. The overall results therefore clarify the contribution of inorganic and organic matter to water adsorption in shale and provide a better understanding of the significance of adsorbed water in shale.Zubrin, R., 2020. Exchange of material between solar systems by random stellar encounters. International Journal of Astrobiology 19, 43-48. is shown that a mechanism involving only random motion of the sun with respect to the surrounding star field can account for the ~1 per 25 Myr characteristic frequency of large cometary impacts on Earth. In the proposed mechanism, the sun travels through the Oort Cloud of an encounter star, most typically a Type M dwarf, while the dwarf flies through the Oort cloud of our Sun. As a result, Oort Cloud objects from our Solar System are precipitated in large numbers to impact planets in the dwarf star system, while the dwarf's Oort Cloud objects are destabilized to impact planets in our Solar System. It is shown that it is this exchange of Oort cloud object between stellar systems, rather than the precipitation of Oort Cloud objects within a stellar system, that can account for the apparent periodicity of mass extinctions. Because the sun is more massive than ~90% of stars, its Oort cloud extends further, resulting in it delivering about a factor of three more bombardments on other solar systems than our Solar System receives. About 60% of the bombardments on our Solar System are found to be delivered by Type M dwarfs, about 20% by type K dwarfs, with the remaining 20% being delivered by stars of type G or larger. Foreign star Oort cloud objects can be captured by our Sun at typical ranges of 10 AU, resulting in a cometary approach to perihelion within a few years. It is found that assuming an effective Oort Cloud radius of 40 000 AU for a star of solar mass, increasing in size with the square root of the mass, accounts for the observed characteristic frequency of mass extinction events on Earth, given the local stellar number density of 0.003 stars per cubic light year. The frequency of mass extinction events in other solar systems would increase or decrease in linear proportion to the local stellar number density. It is shown that this exchange of materials between solar systems during close stellar encounters could be an important mechanism for spreading life throughout the galaxy. Implications for the evolution of life on Earth and in other solar systems are discussed.Zuo, H., Deng, S., Li, H., 2019. Limitations of lattice Boltzmann modeling of micro-flows in complex nanopores. Acta Geologica Sinica - English Edition 93, 1808-1822. multiscale transport mechanism of methane in unconventional reservoirs is dominated by slip and transition flows resulting from the ultra-low permeability of micro/nano-scale pores, which requires consideration of the microscale and rarefaction effects. Traditional continuum-based computational fluid dynamics (CFD) becomes problematic when modeling micro-gaseous flow in these multiscale pore networks because of its disadvantages in the treatment of cases with a complicated boundary. As an alternative, the lattice Boltzmann method (LBM), a special discrete form of the Boltzmann equation, has been widely applied to model the multi-scale and multi-mechanism flows in unconventional reservoirs, considering its mesoscopic nature and advantages in simulating gas flows in complex porous media. Consequently, numerous LBM models and slip boundary schemes have been proposed and reported in the literature. This study investigates the predominately reported LBM models and kinetic boundary schemes. The results of these LBM models systematically compare to existing experimental results, analytical solutions of Navier-Stokes, solutions of the Boltzmann equation, direct simulation of Monte Carlo (DSMC) and information-preservation DSMC (IP_DSMC) results, as well as the numerical results of the linearized Boltzmann equation by the discrete velocity method (DVM). The results point out the challenges and limitations of existing multiple-relaxation-times LBM models in predicting micro-gaseous flow in unconventional reservoirs.Zyakun, A.M., Kochetkov, V.V., Zakharchenko, V.N., Baskunov, B.P., Peshenko, V.P., Laurinavichius, K.S., Siunova, T.V., Anokhina, T.O., Boronin, A.M., 2019. Application of high-performance liquid chromatography/high resolution mass spectrometry to the investigation of the biodegradation and transformation of phenanthrene by a plasmid bearing rhizosphere bacteria Pseudomonas aureofaciens. Journal of Analytical Chemistry 74, 1355-1361. spectrometry was applied to identify metabolites and estimate the efficiency of phenanthrene biodegradation and transformation by rhizosphere bacteria Pseudomonas aureofaciens BS1393. Strains P.?aureofaciens BS1393(pOV17) and P. aureofaciens BS1393(NPL-41) bearing various naphthalene biodegradation plasmids were used in the work. The strain BS1393(pOV17) contains the pOV17 wild type naphthalene biodegradation plasmid that determines the oxidation of naphthalene to Krebs cycle metabolites. The strain BS1393(NPL-41) contains the mutant plasmid NPL-41 governing the initial stages of naphthalene oxidation into salicylic acid. The limiting stages of phenanthrene biodegradation in bacteria with various plasmids have been identified according to the accumulation of intermediates. When bacteria were grown on phenanthrene, the main metabolites were as follows: (a) 2-hydroxy-2H-benzo[h]chromene-2-carboxylic acid/trans-4-(1-hydroxynaph-2-yl)-2-oxobut-3-enoic acid, (b) 1-hydroxy-2-naphthoic acid, and (c) salicylic acid. In the strain BS1393(pOV17), metabolite (а) was observed during 1–14 days of cultivation. Unlike it, in the strain BS1393(NPL-41), an insignificant amount of this metabolite was found after only 14 days. The availability of metabolite (b) in the growth of both strains was an evidence of the limited rate of its further decarboxylation. Metabolite (c) as a final product was found in the growth of the strain BS1393(NPL-41). Contrastingly, in the strain BS1393(pOV17), this metabolite was not found, which indicates the complete oxidation of phenanthrene. ................
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